Patent Application
20150183446
The present disclosure relates to railcar trucks, and more particularly to roller bearing adapter and adapter-pad systems that can improve stiffness, damping, and displacement characteristics to satisfy both curving and high speed performance of a three-piece railcar truck.
The conventional railway freight car truck in use in North America for many decades has been the three-piece truck, comprising a pair of parallel side frames connected by a transversely mounted bolster. The bolster is supported on the side frames by spring groups consisting of a number of individual coil springs. The wheelsets of the truck are received in bearing adapters placed in leading and trailing pedestal jaws in the side frames, so that axles of the wheelsets are parallel in a transverse or lateral position relative to the two rails. The railway car is mounted on the center plate of the bolster, which allows the truck to rotate with respect to the car. The spring groups and side frame to bolster clearance stops permit the side frames to move somewhat with respect to the bolster, about the longitudinal, vertical and transverse or lateral axes.
It has long been desired to improve the performance of the three-piece truck. Resistance to lateral and longitudinal loads and truck performance can be characterized in terms of one or more of the following well-known phenomena.
“Parallelogramming” occurs when one side frame moves forward longitudinally with respect to the other, such that the leading and trailing wheel sets remain parallel to each other but they are not perpendicular to the rails, as may happen when a railway car truck encounters a curve. This action of parallelogramming side frames is also referred to as truck warp.
“Hunting” describes an oscillating sinusoidal longitudinal and lateral movement of the wheelsets that causes the railcar body to move side-to-side. This sinusoidal movement is the harmonic oscillation caused by the tapered profile of the wheelset. While the tapered profile promotes natural oscillation of the wheelset, it is also the primary feature that allows the wheelsets to develop a rolling radius difference and negotiate curves. Hunting may be dangerous when the oscillations attain a resonant frequency. Hunting is more likely to occur when there is a lack of proper alignment in the truck as manufactured, or developed over time through various operating conditions such as wear of the truck components. Hunting is also more likely to occur when the railcar is operated at higher speeds. The speed at which hunting is observed to occur is referred to as the “hunting threshold.”
Several approaches have been tried to improve the stability of the standard three-piece truck to prevent parallelogramming and hunting, while at the same time ensuring that the truck is able to develop the appropriate geometry to accommodate the different distances traveled by the wheels on the inside and outside of a turn, respectively. Additional improvement is desired, both to meet truck hunting requirements as well as to simultaneously improve stiffness, damping, and displacement characteristics that yield good high speed and curving performance.
This Summary provides an introduction to some general concepts relating to this invention in a simplified form that are further described below in the Detailed Description.
Aspects of the disclosure herein relate to railcar trucks. In one example, the disclosure provides a railcar truck including a three-piece truck comprising a bolster, a first side frame having a first pedestal of AAR standard geometry and a second pedestal of AAR standard geometry, and a second side frame having a third pedestal of AAR standard geometry and a fourth pedestal of AAR standard geometry, each side frame pedestal defining a first outer side and a second outer side and having a pedestal roof located and extending between the first outer side and the second outer side. The railcar truck can include a first wheelset engaged with a first roller bearing and engaged with a second roller bearing; a second wheelset engaged with a third roller bearing and engaged with a fourth roller bearing; a first roller bearing adapter having AAR standard thrust lug clearances engaged with the first roller bearing, a second roller bearing adapter having AAR standard thrust lug clearances engaged with the second roller bearing, a third roller bearing adapter having AAR standard thrust lug clearances engaged with the third roller bearing, and a fourth roller bearing adapter having AAR standard thrust lug clearances engaged with the fourth roller bearing each roller bearing, each roller bearing adapter symmetrical about a lateral centerline and symmetrical about a longitudinal centerline, and defining a bottom surface and a crowned top surface, the top surface defining opposing first and second vertical shoulders that project upwardly from the top surface on either side of the side frame. The railcar truck can also include a first adapter pad engaged with the first pedestal roof and the first roller bearing adapter, a second adapter pad engaged with the second pedestal roof and the second roller bearing adapter, a third adapter pad engaged with the third pedestal roof and the third roller bearing adapter, a fourth adapter pad engaged with the fourth pedestal roof and the fourth roller bearing adapter, and each adapter pad includes a continuous top plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a continuous bottom plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a first outer elastomeric member disposed between the first lateral flanges of the top and bottom plates, defining a first outer edge, and having a static thickness within the range of 0.15 inches to 0.30 inches; a second outer elastomeric member disposed between the second lateral flanges of the top and bottom plates, defining a second outer edge, and having a static thickness within the range of 0.15 inches to 0.30 inches; a central elastomeric member disposed between the central portion of the top and bottom plates, defining a third outer edge, having a substantially uniform thickness, and having a static thickness within the range of 0.15 inches to 0.25 inches; a first substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the first outer elastomeric member; a second substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the second outer elastomeric member; a first lateral adapter grip disposed between an inside surface of the first vertical shoulder of the engaged roller bearing adapter and the first upturned region of the bottom plate; a second lateral adapter grip disposed between an inside surface of the second vertical shoulder of the engaged roller bearing adapter and the second upturned region of the bottom plate; a first lateral side frame grip disposed between an outer surface of the first upturned region of the top plate and the first outer side of the engaged side frame pedestal; a second lateral side frame grip disposed between an outer surface of the second upturned region of the top plate and the second outer side of the engaged side frame pedestal. The top plate and bottom plate central portions and the central elastomeric member of each adapter pad can be disposed at least in part beneath the engaged pedestal roof, and the first and second laterally projecting flanges of the top plate and the bottom plate and the first and second outer elastomeric members of each adapter pad can be entirely disposed above the vertical shoulders of the engaged roller bearing adapter and outside of the engaged pedestal roof; and the combined top plate, bottom plate, and elastomeric members of each of the adapter pads can provide a longitudinal stiffness of at least 45,000 pounds per inch through a longitudinal displacement of the top plate relative to the bottom plate of up to 0.139 inches from a central position, a lateral stiffness of at least 45,000 pounds per inch through a lateral displacement of the top plate relative to the bottom plate of up to 0.234 inches from the central position, and a rotational stiffness of at least 250,000 pound*inches per radian of rotation through a rotational displacement of the top plate relative to the bottom plate of up to 41 milliradians from the central position when a vertical load of 35,000 pounds is applied to the central portions of the adapter pad.
In another example the disclosure provides railcar truck including a three-piece truck with a bolster and at least one side frame having at least one side frame pedestal defining a first outer side and a second outer side, and a pedestal roof located and extending between the first outer side and the second outer side. The railcar truck can include at least one wheelset positioned transversely with the at least one side frame; at least one roller bearing engaged with the at least one wheelset; at least one roller bearing adapter, defining a bottom surface and a top surface, the bottom surface engaged with the roller bearing, the top surface defining opposing first and second vertical shoulders that project upwardly from the top surface, on either side of the at least one side frame; at least one adapter pad configured to engage with the at least one roller bearing adapter and the pedestal roof, the at least one adapter pad including a top plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a bottom plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a first outer elastomeric member disposed between the first lateral flanges of the top and bottom plates; a second outer elastomeric member disposed between the second lateral flanges of the top and bottom plates; a central elastomeric member disposed between the central portion of the top and bottom plates; a first substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the first outer elastomeric member; a second substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the second outer elastomeric member. The top plate and bottom plate central portions and the central elastomeric member can be disposed at least in part beneath the pedestal roof, and the first and second laterally projecting flanges of the top plate and the bottom plate and the first and second outer elastomeric members can be disposed above the vertical shoulders of the roller bearing adapter and entirely outside of the pedestal roof; and the top plate of the at least one adapter pad can be engaged with the at least one side frame such that movement between the top plate and the at least one side frame is restricted, and wherein the bottom plate of the adapter pad is engaged with the roller bearing adapter such that movement between the bottom plate and the roller bearing adapter is restricted.
In another example, the disclosure provides a railcar truck including a three-piece truck with a bolster; and a side frame having a side frame pedestal defining a first outer side and a second outer side, and a pedestal roof located and extending between the first outer side and the second outer side. The railcar truck can also include a wheelset; a roller bearing engaged with the wheelset; a roller bearing adapter, defining a bottom surface and a top surface, the bottom surface engaged with the roller bearing, the top surface defining opposing first and second vertical shoulders that project upwardly from the top surface on either side of the side frame; and an adapter pad configured to engage with the roller bearing adapter and the pedestal roof. The adapter pad can include a top plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a bottom plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a first outer elastomeric member disposed between the first lateral flanges of the top and bottom plates; a second outer elastomeric member disposed between the second lateral flanges of the top and bottom plates; a central elastomeric member disposed between the central portion of the top and bottom plates. The top plate and bottom plate central portions and the central elastomeric member can be disposed at least in part beneath the pedestal roof, and the first and second laterally projecting flanges of the top plate and the bottom plate and the first and second outer elastomeric members can be disposed above the vertical shoulders of the roller bearing adapter and entirely outside of the pedestal roof; the top plate of the adapter pad can be fixedly engaged with the side frame such that movement between the top plate and the side frame is restricted, and wherein the bottom plate of the adapter pad is fixedly engaged with the roller bearing such that movement between the bottom plate and the roller bearing is restricted; and the combined surface area of the first and second outer elastomeric members at cross-sectional planes through the first and second outer elastomeric members in planes centered between the inner surfaces of the top and bottom plates can be at least 10 percent of the surface area of the central elastomeric member at a cross-section plane through the center of the central elastomeric member in a centered between the inner surfaces of the top and bottom plates.
Aspects of the disclosure herein also relate to adapter pads and adapter pad system. In one example, the disclosure provides a roller bearing adapter pad system configured for use with a three-piece truck having AAR standard geometry including a roller bearing adapter configured to engage a roller bearing. The roller bearing adapter can include a crowned top surface; a bottom surface configured to engage a roller bearing; first and second vertical shoulders that project upwardly from opposite lateral edges of the top surface, each vertical shoulder having a width of at least 0.5 inches; first and second longitudinal stops that project upwardly from opposite longitudinal edges of the top surface. The roller bearing adapter can be symmetrical about a lateral centerline and symmetrical about a longitudinal centerline; the thickness of the roller bearing adapter measured between the crowned top surface and the bottom surface can be less than 0.75 inches as measured at the longitudinal centerline; the roller bearing adapter can have cross-sectional moment of inertia of a cross-section at the longitudinal centerline of the roller bearing adapter around a lateral axis about 5.2 inches above a center axis of an axle that is in the range of about 1.0 in4 to about 2.0 in4; and the roller bearing adapter can have a cross-sectional moment of inertia of a cross-section at the longitudinal centerline of the roller bearing adapter around a vertical axis at the center of the adapter that is in the range of about 50 in4 to about 100 in4. The roller bearing adapter system also can include an adapter pad engaged with the roller bearing adapter and configured to engage a side frame pedestal roof, the adapter pad including a continuous top plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a continuous bottom plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a first outer elastomeric member disposed between the first lateral flanges of the top and bottom plates, having a substantially uniform static thickness within the range of 0.15 inches to 0.30 inches; a second outer elastomeric member disposed between the second lateral flanges of the top and bottom plates, having a static thickness within the range of 0.15 inches to 0.30 inches; a central elastomeric member disposed between the central portion of the top and bottom plates, having a static thickness within the range of 0.15 inches to 0.25 inches; a first substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the first outer elastomeric member; a second substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the second outer elastomeric member; a first lateral adapter grip disposed between an inside surface of the first vertical shoulder of the engaged roller bearing adapter and the first upturned region of the bottom plate; a second lateral adapter grip disposed between an inside surface of the second vertical shoulder of the engaged roller bearing adapter and the second upturned region of the bottom plate; a first lateral side frame grip disposed on an outer surface of the first upturned region of the top plate; a second lateral side frame grip disposed between an outer surface of the second upturned region of the top plate. The first and second laterally projecting flanges of the top plate and the bottom plate and the first and second outer elastomeric members of each adapter pad can be entirely disposed above the vertical shoulders of the roller bearing adapter.
In another example, the disclosure provides a roller bearing adapter pad system configured for use with a three-piece truck having AAR standard geometry including a roller bearing adapter configured to engage a roller bearing. The bearing adapter can include a top surface; a bottom surface configured to engage a roller bearing; first and second vertical shoulders that project upwardly from opposite lateral edges of the top surface, each vertical shoulder having a width of at least 0.5 inches and a height in the range of 0.75 inches to 1.5 inches. The roller bearing adapter system can include an adapter pad engaged with the roller bearing adapter and configured to engage a side frame pedestal roof, the adapter pad including a continuous top plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a continuous bottom plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a first outer elastomeric member disposed between the first lateral flanges of the top and bottom plates, defining a first outer edge; a second outer elastomeric member disposed between the second lateral flanges of the top and bottom plates, defining a second outer edge; a central elastomeric member disposed between the central portion of the top and bottom plates, defining a third outer edge; a first substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the first outer elastomeric member; a second substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the second outer elastomeric member. The first and second laterally projecting flanges of the top plate and the bottom plate and the first and second outer elastomeric members of each adapter pad can be entirely disposed above the vertical shoulders of the roller bearing adapter; the combined surface area of the first and second outer elastomeric members at cross-sectional planes through the first and second outer elastomeric members in planes centered between the inner surfaces of the top and bottom plates can be at least 10 percent of the surface area of the central elastomeric member at a cross-section plane through the center of the central elastomeric member in a centered between the inner surfaces of the top and bottom plates; and the combined top plate, bottom plate, and elastomeric members provide a longitudinal stiffness of at least 45,000 pounds per inch through a longitudinal displacement of the top plate relative to the bottom plate of up to 0.139 inches from a central position, a lateral stiffness of at least 45,000 pounds per inch through a lateral displacement of the top plate relative to the bottom plate of up to 0.234 inches from the central position, and a rotational stiffness of at least 250,000 pound*inches per radian of rotation through a rotational displacement of the top plate relative to the bottom plate of up to 41 milliradians from the central position when a vertical load of 35,000 pounds is applied to the central portions of the adapter pad.
In another example, the disclosure provides a roller bearing adapter pad configured for use with a three-piece truck including a continuous top plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a continuous bottom plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a first outer elastomeric member disposed between the first lateral flanges of the top and bottom plates; a second outer elastomeric member disposed between the second lateral flanges of the top and bottom plates; a central elastomeric member disposed between the central portion of the top and bottom plates; a first substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the first outer elastomeric member; a second substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the second outer elastomeric member. The combined top plate, bottom plate, and elastomeric members of the adapter pad can provide a longitudinal stiffness of at least 45,000 pounds per inch through a longitudinal displacement of the top plate relative to the bottom plate of up to 0.139 inches from a central position, a lateral stiffness of at least 45,000 pounds per inch through a lateral displacement of the top plate relative to the bottom plate of up to 0.234 inches from the central position, and a rotational stiffness of at least 250,000 pound*inches per radian of rotation through a rotational displacement of the top plate relative to the bottom plate of up to 41 milliradians from the central position when a vertical load of 35,000 pounds is applied to the central portions of the adapter pad.
In another example, the disclosure provides a roller bearing adapter pad system configured for use with a three-piece truck having AAR standard geometry. The roller bearing adapter pad system can a roller bearing adapter configured to engage a roller bearing, wherein the roller bearing adapter includes a crowned top surface; a bottom surface configured to engage a roller bearing; wherein the roller bearing adapter has cross-sectional moment of inertia of a cross-section at the longitudinal centerline of the roller bearing adapter around a lateral axis about 5.2 inches above a center axis of an axle that is in the range of about 1.0 in4 to about 2.0 in4; and wherein the roller bearing adapter has a cross-sectional moment of inertia of a cross-section at the longitudinal centerline of the roller bearing adapter around a vertical axis at the center of the adapter that is in the range of about 50 in4 to about 100 in4. The roller bearing adapter pad system can also include an adapter pad engaged with the roller bearing adapter and configured to engage a side frame pedestal roof, wherein the adapter pad includes a continuous top plate; a continuous bottom plate; an elastomeric member disposed between the top and bottom plates, having a static thickness within the range of 0.15 inches to 0.30 inches; and wherein the surface area of the elastomeric member at a cross-sectional plane centered between the inner surfaces of the top and bottom plates is greater than about 50 square inches. The combined top plate, bottom plate, and elastomeric members of the roller bearing adapter pad system can provide a longitudinal stiffness of at least 45,000 pounds per inch through a longitudinal displacement of the top plate relative to the bottom plate of up to 0.139 inches from a central position, a lateral stiffness of at least 45,000 pounds per inch through a lateral displacement of the top plate relative to the bottom plate of up to 0.234 inches from the central position, and a rotational stiffness of at least 250,000 pound*inches per radian of rotation through a rotational displacement of the top plate relative to the bottom plate of up to 41 milliradians from the central position when a vertical load of 35,000 pounds is applied to the central portion of the adapter pad.
Aspects of the disclosure herein also relate to methods for forming railcar trucks, adapter pad systems, and adapter pads. In one example, the disclosure provides a method for forming a railcar truck including providing a three-piece truck. The method can include providing a three-piece truck including a bolster; and a first side frame having a first pedestal of AAR standard geometry and a second pedestal of AAR standard geometry, and a second side frame having a third pedestal of AAR standard geometry and a fourth pedestal of AAR standard geometry, each side frame pedestal defining a first outer side and a second outer side and having a pedestal roof located and extending between the first outer side and the second outer side. The method further can include providing a first wheelset engaged with a first roller bearing and engaged with a second roller bearing; providing a second wheelset engaged with a third roller bearing and engaged with a fourth roller bearing; providing a first roller bearing adapter having AAR standard thrust lug clearances engaged with the first roller bearing, a second roller bearing adapter having AAR standard thrust lug clearances engaged with the second roller bearing, a third roller bearing adapter having AAR standard thrust lug clearances engaged with the third roller bearing, and a fourth roller bearing adapter having AAR standard thrust lug clearances engaged with the fourth roller bearing each roller bearing, each roller bearing adapter symmetrical about a lateral centerline and symmetrical about a longitudinal centerline, and defining a bottom surface and a crowned top surface, the top surface defining opposing first and second vertical shoulders that project upwardly from the top surface on either side of the side frame. The method further can include providing a first adapter pad, a second adapter pad, a third adapter pad, a fourth adapter pad, each adapter pad including a continuous top plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a continuous bottom plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; a first outer elastomeric member disposed between the first lateral flanges of the top and bottom plates, defining a first outer edge, and having a static thickness within the range of 0.15 inches to 0.30 inches; a second outer elastomeric member disposed between the second lateral flanges of the top and bottom plates, defining a second outer edge, and having a static thickness within the range of 0.15 inches to 0.30 inches; a central elastomeric member disposed between the central portion of the top and bottom plates, defining a third outer edge, and having a static thickness within the range of 0.15 inches to 0.25 inches; a first substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the first outer elastomeric member; a second substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the second outer elastomeric member; a first elastomeric lateral adapter grip disposed between an inside surface of the first vertical shoulder of the engaged roller bearing adapter and the first upturned region of the bottom plate; a second elastomeric lateral adapter grip disposed between an inside surface of the second vertical shoulder of the engaged roller bearing adapter and the second upturned region of the bottom plate; a first elastomeric lateral side frame grip disposed between an outer surface of the first upturned region of the top plate and the first outer side of the engaged side frame pedestal; a second elastomeric lateral side frame grip disposed between an outer surface of the second upturned region of the top plate and the second outer side of the engaged side frame pedestal. The method further can include engaging the first adapter pad with the first pedestal roof and the first roller bearing adapter such that movement of the top plate of the first adapter pad relative to the pedestal roof is restricted and that movement between the bottom plate of the first adapter pad relative to the first roller bearing adapter is restricted; engaging the second adapter pad with the second pedestal roof and the second roller bearing adapter such that movement of the top plate of the second adapter pad relative to the pedestal roof is restricted and that movement between the bottom plate of the second adapter pad relative to the second roller bearing adapter is restricted; engaging the third adapter pad with the third pedestal roof and the third roller bearing adapter such that movement of the top plate of the third adapter pad relative to the pedestal roof is restricted and that movement between the bottom plate of the third adapter pad relative to the third roller bearing adapter is restricted; engaging the fourth adapter pad with the fourth pedestal roof and the fourth roller bearing adapter such that movement of the top plate of the fourth adapter pad relative to the pedestal roof is restricted and that movement between the bottom plate of the fourth adapter pad relative to the fourth roller bearing adapter is restricted. The top plate and bottom plate central portions and the central elastomeric member of each adapter pad can be disposed at least in part beneath the engaged pedestal roof, and the first and second laterally projecting flanges of the top plate and the bottom plate and the first and second outer elastomeric members of each adapter pad can be entirely disposed above the vertical shoulders of the engaged roller bearing adapter and outside of the engaged pedestal roof.
In another example, the disclosure provides a method of forming an adapter pad system configured for use with three-piece truck having AAR standard geometry including providing a roller bearing adapter with AAR standard thrust lug clearances engaged with the first roller bearing, the roller bearing adapter symmetrical about a lateral centerline and symmetrical about a longitudinal centerline, and defining a bottom surface and a crowned top surface, the top surface defining opposing first and second vertical shoulders that project upwardly from the top surface, and providing an adapter pad configured to engage a pedestal roof and the roller bearing adapter the adapter pad including providing a continuous top plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; providing a continuous bottom plate having a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; providing a first outer elastomeric member disposed between the first lateral flanges of the top and bottom plates; providing a second outer elastomeric member disposed between the second lateral flanges of the top and bottom plates; providing a central elastomeric member disposed between the central portion of the top and bottom plates; providing a first substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the first outer elastomeric member; providing a second substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the second outer elastomeric member. The method further can include compressing the first and second outer elastomeric members; and engaging the adapter pad with the first roller bearing adapter such that movement of the bottom plate of the first adapter pad with respect to the roller bearing adapter is restricted. The first and second laterally projecting flanges of the top plate and the bottom plate and the first and second outer elastomeric members of each adapter pad can be entirely disposed above the vertical shoulders of the roller bearing adapter.
In another example, the disclosure provides a method for forming an adapter pad including providing a continuous top plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned region, and a second lateral flange projecting outward from the second upturned region; providing a continuous bottom plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned region, and a second lateral flange projecting outward from the second upturned region; inserting a first outer elastomeric member between the first lateral flanges of the top and bottom plates; inserting a second outer elastomeric member between the second lateral flanges of the top and bottom plates; inserting a central elastomeric member between the central portion of the top and bottom plates; forming a first substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the first outer elastomeric member; forming a second substantially hollow portion disposed between the top plate and the bottom plate and between the central elastomeric member and the second outer elastomeric member; compressing the first outer elastomeric members; and compressing the second outer elastomeric members.
In the following description of various example structures according to the invention, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various example devices, systems, and environments in which aspects of the invention may be practiced. It is to be understood that other specific arrangements of parts, example devices, systems, and environments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. Also, while the terms “top,” “bottom,” “front,” “back,” “side,” “rear,” and the like may be used in this specification to describe various example features and elements of the invention, these terms are used herein as a matter of convenience, e.g., based on the example orientations shown in the figures or the orientation during typical use. Additionally, the term “plurality,” as used herein, indicates any number greater than one, either disjunctively or conjunctively, as necessary, up to an infinite number. Nothing in this specification should be construed as requiring a specific three dimensional orientation of structures in order to fall within the scope of this invention. Also, the reader is advised that the attached drawings are not necessarily drawn to scale.
In general, aspects of this invention relate to a railcar truck, and railcar truck roller bearing adapters and adapter pads. According to various aspects and embodiments, the railcar truck and the railcar truck roller bearing adapters and adapter pads may be formed of one or more of a variety of materials, such as metals (including metal alloys), polymers, and composites, and may be formed in one of a variety of configurations, without departing from the scope of the invention. It is understood that the railcar truck roller bearing adapters and adapter pads may contain components made of several different materials. Additionally, the components may be formed by various forming methods. For example, metal components, may be formed by forging, molding, casting, stamping, machining, and/or other known techniques. Additionally, polymer components, such as elastomers, can be manufactured by polymer processing techniques, such as various molding and casting techniques and/or other known techniques.
The various figures in this application illustrate examples of railcar trucks, railcar truck roller bearing adapters, and adapter pads according to this invention. When the same reference number appears in more than one drawing, that reference number is used consistently in this specification and the drawings refer to the same or similar parts throughout.
As shown in
The side frames 4 are arranged longitudinally, e.g., in the direction of the rails upon which the truck sits. The bolster 6 is aligned transversely or laterally with respect to the side frames 4 and extends through the middle of each side frame 4.
The bolster bowl 12 is the round section of the bolster 6 that includes a rim that protrudes upward. The body centerplate of the car body rests in the bolster bowl 12 and acts as a rotation point for the truck and car body. It is at this interface that the majority of the vertical load of the freight car is reacted. Usually, the bolster bowl 12 is equipped with wear plates or a wear liner so that the bolster casting 6 is prevented from wear during the service life of the freight car. Also on the top surface of the bolster 6 and located 25 inches off the centerline are the side bearings 14, which can help stabilize the car body and can provide some prevention of truck hunting if they are of the constant contact type. The side bearings 14 shown in
The bolster 6 rests on top of spring groups 8 that are supported underneath by the spring seat of the side frames. Additional springs, often called snubber or side springs 17, can also be part of the spring group and rest on the spring seat extending upward to the bottom of friction wedges 16 that can be part of the friction damping system.
The friction wedges 16 can be located in pockets at the end of and to each side of the bolster 6. The friction wedge pockets of the bolster can be angled, typically at an angle of about 60° from horizontal matching the angle surface of the friction wedges. The opposite face of a friction wedge 16 is typically vertical and contacts what is called the column face of the side frame. The spring force of the snubber springs 17 pushes the friction wedge 16 against the angled surface of the bolster friction wedge pocket which creates a reaction force against the vertical column face of the side frame.
As the bolster 6 moves up and down under the load from the freight car resting on the truck, the sliding of the friction wedge 16 against the column face can create column friction damping. This damping can provide for a dissipation of energy that prevents the freight car from developing undesired vibrations/oscillations when moving in railroad service. It is also these forces acting between the bolster 6 and side frame 4 through the friction wedges 16 that seeks to prevent the truck from taking on a parallelogram geometry when under operation. Hard stops, such as the gibs and rotation stops, help prevent trucks from taking on an extreme parallel shape. This resistance to parallelogramming is often called warp stiffness.
As shown in
Because the vertical load varies with the lading weight contained in the freight car and with the rocking motion of the freight car on the truck, the frictional forces at the metal adapter crown and steel pedestal roof wear plate can vary considerably and are not controlled in the typical truck. This metal to metal connection requires large wheelset forces to force sliding at the interfacing surface due to the stick-slip nature of metal sliding connections. More recent truck designs, such as those trucks qualified under the American Association of Railroads (“AAR”) M-976 specification, now include an adapter pad at the interface between the steel adapter and the pedestal roof.
Some adapter pad systems have been successful in lowering wheelset forces during railcar curving by allowing low stiffness compliance between the side frame and axle. This added compliance created by the adapter pad also reduces the force it takes to pull or push a railcar through a curve as required in the M-976 specification, which is incorporated herein by reference. Adversely, these designs have lowered the speed at which the car resonates during tangential track travel, otherwise described as lowering the hunting speeds of the cars. Lowering the hunting speed is a disadvantage because it limits the operating speeds of the trains and increases the risk of derailing cars or damaging track. Other designs utilize premium side frame squaring devices such as transoms, frame bracing, steering arms, spring planks, yaw dampers, cross bracing, or additional friction wedges to improve the hunting performance. These systems, generally referred to as premium truck technology, typically increase the wheelset forces and therefore the pulling resistance during curving. In addition to increasing curve resistance, these designs have traditionally increased truck maintenance costs due to the added wear components and system complexity.
Adapter pad system embodiments described herein can meet the curving performance criteria set forth in M-976, without decreasing the critical hunting threshold. The adapter pad systems described herein also do not require any additional side frame squaring devices, such as transoms, frame bracing, steering arms, spring planks, yaw dampers, cross bracing, or additional friction wedges, to be added to a standard 3-piece truck. The resulting truck system described herein can improve the life of the wheelsets, maintain a high hunting threshold, improve the durability of the pad system, and minimize wear and forces exerted on the rails.
By way of background, there are many different rail car types and services native to the North American Rail Industry which require different truck sizes. Cars designed for 70 ton service have a Gross Rail Load of 220,000 lbs., and commonly use 28 inch or 33 inch wheels with 6 inch×11 inch bearings. Cars designed for 100 ton service have a Gross Rail Load of 263,000 lbs., and commonly use 36 inch wheels with 6.5 inch×12 inch bearings. Cars designed for 110 ton service have a Gross Rail Load of 286,000 lbs. and must meet the performance specification M-976 as mentioned above. These 110 ton cars typically use 36 inch wheels with 6.5 inch×9 inch bearings. The final car type typical to North America is designed for 125 ton service and has a Gross Rail Load of 315,000 lbs. This car type typically uses 38 inch wheels with 7 inch×12 inch bearings. The other truck sizes −70 ton, 100 ton, and 125 ton are not subject to the same strict performance standard, and thus have not required the use of pads to date.
The roller bearing adapter and matching adapter pad are the focus of this application. Embodiments of the disclosed adapter and matching adapter pad system can be used with cars designed for 110 ton service and can be scalable for use with and improve the performance of trucks for all car capacities (including 70 ton, 100 ton, 110 ton, and 125 ton), including those trucks that do not require compliance with the M-976 standard.
One embodiment of the adapter pad system 198 is shown in at least
In some embodiments, as shown in at least
It has been determined through testing that the performance of the truck system is highly influenced by the stiffness of the adapter pad 200. More specifically, in certain embodiments, it has been determined that truck performance can be improved with improved adapter pad system performance. The adapter pad system performance can be improved by increasing the stiffness of the adapter pad system 198 (measured in pounds of force per inch of displacement). Additionally, for example, it has been determined that acceptable life expectancy (measured in distance traveled under load of a truck system that includes an adapter pad 200 installed, which a design life has been determined to be 1 million miles of railcar travel) is expected for an adapter pad 200 like embodiments discussed herein when a longitudinal stiffness is at least 45,000 pounds per inch or in the range of about 45,000 pounds per inch to about 80,000 pounds per inch, and/or when a lateral stiffness is at least 45,000 pounds per inch or in the range of about 45,000 pounds per inch to about 80,000 pounds per inch, and/or when a rotational stiffness (i.e. stiffness to resist rotation about the vertical axis) is at least 250,000 pound*inches per radian or in the range of about 250,000 pound*inches per radian to about 840,000 pound*inches per radian (each of these measured when a 35,000 pound vertical load is applied to the central portion of the adapter 200). These unique stiffness combinations can maximize the hunting threshold speed, while still maintaining a curve resistance below 0.40 lbs/ton/degree of curvature as required by the M-976 specification without the use of premium truck technologies utilizing transoms, frame bracing, steering arms, spring planks, yaw dampers, cross bracing, or additional friction wedges to improve performance.
Stiffness of the adapter pad system is quantified by measuring the adapter assembly resistance to relative shear displacement of the top plate (which is engaged with the side frame), and the bottom plate (which is engaged with the roller bearing adapter). To determine the stiffness, the adapter assembly can be displaced relative to the side frame in multiple directions, such as, longitudinal (in the direction of railcar travel), lateral (across the rail tracks), yaw (rotation about a vertical axis and in line with axle center line), and vertical (between side frame pedestal roof and adapter pad top surface). A vertical load of 35,000 should be maintained during shear stiffness testing to simulate a loaded car scenario.
During testing, the force to displace the top plate relative to the bottom plate can be measured using load cells attached to a force actuator. Displacement measurements can be collected with displacement transducers, dial indicators, potentiometers, or other displacement measuring instruments. As described in more detail below, the force and displacement is plotted, with the slope of the hysteresis loop indicating the stiffness in the respective direction. The area contained within the loop is proportional to the energy displaced during the load cycle.
Embodiments of the adapter pad system 198 described herein provide a thrust lug opening width and spacing sufficient to not limit displacement within the AAR values, even with the use of high stiffness shear pads as described herein. The disclosed adapter design may utilize target adapter displacements shown in Table 1 below.
Disclosed embodiments of the adapter pad system 198 with the disclosed longitudinal, lateral, and rotational shear stiffness as described herein can provide an advantageous combination of high speed stability and low curve resistance for the a-piece truck system. Disclosed embodiments of the adapter pad system 198 can increase the warp restraint of the 3-piece truck system as compared to other adapter pad designs. This can allow for increased high speed stability. In addition to improvements in high speed stability, embodiments of the adapter pad system 198 described herein can promote longitudinal displacement of the wheelset during curving, allowing the leading and trailing axle of the truck assembly to develop an inter-axle yaw angle proportional to the curve which can lower wheelset forces. In combination, the adapter pad system 198 promotes lateral wheelset shift to develop an optimal rolling radius difference during curving. The adapter pad system stiffness and displacement ranges disclosed herein can allow for optimal inter-axle yaw angle and lateral wheelset shift, promoting low wheelset force solution through curves. Reduction in curving forces and improved high speed stability can contribute to improvements in wheelset and rail life.
Some adapter pad designs utilize multiple elastomer layers to reduce shear strain. These multiple layers can add significant thickness to the adapter system and when used in conventional trucks, raise the height of the car. Raising the height of the car creates issues coupling to other cars, as well as raises the center of gravity. As a result some designs required the use of special, non-conventional side frames to minimize the height difference. Embodiments discussed herein can allow for improved dynamic performance, without requiring the use of special, non-conventional truck components.
Embodiments discussed herein can be used with side frames having AAR standard geometry, including AAR standard pedestal geometry and AAR standard thrust lug clearances, as described in the Association of American Railroads Manual of Standards and Recommended Practices, Section SII (Oct. 25, 2010), Specification S-325 (Jun. 11, 2009)—“Side Frame, Narrow Pedestal—Limiting Dimensions” which is incorporated herein by reference. AAR standard pedestal geometry can be described as including nominal longitudinal thrust lug spacing of about 7.25-8.25 inches; nominal thrust lug width of about 3.5-3.75 inches; nominal longitudinal jaw spacing of about 8.88-11.06 inches; and nominal pedestal roof height above the centerline of the axle of about 5.38-6.89 inches. Embodiments of the adapter pad system 198 disclosed herein can be used with existing and/or standard 3 piece truck systems, including truck systems having AAR standard geometry as described in the Association of American Railroads Manual of Standards and Recommended Practices, and more specifically, Section H (Jan. 1, 2012), Specification M-924 (Feb. 1, 2014)—“Journal Roller Bearing Adapters for Freight Cars” which are incorporated herein by reference. AAR standard thrust lug clearance can be found above in Table 1 for new casting manufacturing dimensions. The thrust lug clearance is determined through the distance between the pedestal area and the roller bearing adapter openings. Standard AAR adapter dimensions can include nominal longitudinal thrust lug bearing surface spacing of about 7.156-8.656 inches; and a nominal lateral thrust lug opening of about 3.812-4.062 inches. Embodiments of the adapter pad system 198 described herein can also meet American Association of Railroads (“AAR”) M-976 specification (AAR Manual of Standards and Recommended Practices, Section D (Sep. 1, 2010), Specification M-976 (Dec. 19, 2013)—“Truck Performance for Rail Cars”) which is incorporated herein by reference. For example, embodiments of the adapter pad system 198 can be used in existing and/or standard 3 piece truck systems without the use of additional pieces such as transoms, frame braces, or spring planks. Additionally, for example, adapter pad systems 198 disclosed herein can fit between the roller bearing 5 and the pedestal roof 152 of existing trucks. Thus, adapter pad systems 198 disclosed herein can have a total height measured between an upper surface of the roller bearing 5 and the pedestal roof 152 of about 1.3 inches or in the range of about 1.1 inches to about 1.5 inches. While the embodiments described herein are specific to the 110T truck, the disclosed adapter and matching adapter pad system can be scalable for use with and improve the performance of trucks for all car capacities (70 ton, 100 ton, 110 ton, and 125 ton), including those trucks that do not require compliance with the M-976 standard.
A roller bearing adapter 198 in accordance with the present disclosure is shown in
As shown in
The roller bearing adapter 199 can include features to limit the motion of the adapter pad 200 relative to the roller bearing adapter 199. For example, the roller bearing adapter can include longitudinal adapter pad stops 104. As shown in
Longitudinal stops can be incorporated into other portions of the adapter pad. For example, as shown in
Various other combinations of sizes, shapes, and locations can be utilized for the longitudinal stops 104 in order to provide the desired restraint of movement.
As shown in
The roller bearing adapter 199 can also include features, such as the vertical shoulders 106, to improve the bending strength or cross-sectional moment of inertia of the adapter 199 to minimize distortion of the adapter 199 under the high forces imparted by the adapter pad 200. For example, for the embodiment shown in
The roller bearing adapter 199 may be made from one or more different types of alloys of steel that have suitable strength and other performance characteristics. For example, roller bearing adapter 199 may be manufactured from cast iron of grade ASTM A-220, A-536, or cast or forged steel of grades ASTM A-148, A-126, A-236, or A-201. In some embodiments, the entire roller bearing adapter 199 is formed (cast, machined, pressed or another suitable metal forming operation) from a single monolithic member.
Moving now to the adapter pad 200 of the adapter system 198 which is configured to be disposed between and can engage with the roller bearing adapter 199 and the side frame pedestal roof 152 of the side frame 4. As shown in
Turning first to the central portion 210, which can in some embodiments comprise primarily three parts including the central portion 226 of the top plate, the central portion 246 of the bottom plate and the elastomeric member 360 disposed therebetween. As discussed above, the adapter pad 200 is disposed between the side frame pedestal roof 152, which generally has a substantially flat horizontal engaging surface, and the roller bearing adapter 199 which can generally have a curved or crowned roof. As shown in
In some embodiments, the central section 226 of the top plate 220 can include an outer surface 224 and an inner surface 222 that are substantially horizontal and parallel as shown in
It has been found that an elastomeric section having a uniform thickness can in some circumstances have certain advantages. For example, in certain embodiments, linear thermal shrinkage can be constant along the length and width of the pad if the plurality of elastomer layers have common length and width dimensions among all members. For example, in some embodiments, during molding the rubber forming the elastomeric member can be injected into the mold at around 300 degrees Fahrenheit, and it can subsequently cool to room temperature. Linear thermal shrink normal to the shear plane can be related to the section thickness “T” the change in temperature, and the coefficient of thermal expansion. A non-uniform elastomer thickness can result in non-uniform shrinkage during the cooling process. Non-uniform shrinkage can result in residual tensile stresses in the areas last to cool which can negatively impact fatigue life.
With further reference to
With further reference to
Although the embodiment of the adapter pad 200 shown in at least
The top plate 220 may be made from one or more different types of alloys with suitable strength and other performance characteristics. For example, the top plate 220 may be manufactured from ASTM A36 steel plate, or steels with a strength equivalent to or higher than those specified in ASTM A-572. In some embodiments, the entire top plate 220 is formed (cast, machined, pressed, rolled, stamped, forged or another suitable metal forming operation) from a single monolithic member. In some embodiments, the top plate 220 may be formed from a material with a constant thickness throughout. In other embodiments, the top plate 220 has a variable thickness. For example in some embodiments, the lateral flanges 232, 236 of the top plate 220 can have a thickness that is greater than or less than the thickness of the center portion 226. Similarly and as previously discussed, the bottom plate 240 can have a constant or variable thickness. In some embodiments, one, some, or all of the corners 233 of the top plate 220 may be curved.
In some embodiments, the outer surface 226 of the top plate 220 may receive a coating of an elastomeric material 265 which may be the material that contacts the pedestal roof 152. As discussed elsewhere herein the elastomeric layer 265 may provide dampening and a calibrated flexibility to the pad, as well as a compressible surface to minimize wear between the adapter pad 199 and the pedestal roof 152. The elastomeric coating 265 may be formed with a flat outer surface that follows along the geometric profile of the steel portion of the top plate 220, and can have a uniform thickness, either along the entire top plate 220, or in other embodiments, a uniform thickness within discrete portions of the pad (such as a uniform thickness in the central portion 210, a (potentially different or potentially the same) uniform thickness on one or both of the upper portions lateral flanges 232, 234, a (potentially different or potentially the same) uniform thickness on one or both of the upturned portions 228, 230, and the like.
During use, there can be heat generation in the adaptor pad 200 through friction of the pad 200 and sliding relative to the side frame pedestal roof 152 and/or relative to the bearing adaptor 199; and or the hysteretic damping of the elastomeric member 360 of the adaptor pad 200. These heat sources can cause adaptor pad temperatures to increase, which can result in lower durability and reduced stiffnesses.
In some embodiments, the first and second lateral flanges 216, 218 can include upper and lower surfaces exposed to air outside of the side frame envelope at the pedestal area (when the adapter pad is installed within a pedestal of a truck). The exposed surfaces can readily allow for heat loss from the adapter pad during operation of the railcar (acting as a fin) and can cause net heat flow from the central portion 210 of the adapter pad 200) and toward the lateral flanges 216, 218. As is easily understood, and as discussed below, heat is generated within the adapter pad 200 during railcar operation due to various reasons, such as due to friction that resists relative translation or rotation between the adapter pad 200 and the side frame and between the adapter pad 200 and the bearing adapter 199. Further, because the adapter pad 200 is in surface-to-surface contact with the side frame 4 and the bearing adapter 199, the adapter pad 200 may receive heat that is generated elsewhere and transferred to the adapter pad 200. Also, the cyclic dampening of the elastomeric portion produces heat. This heat must be ultimately removed to avoid a significant increase in the temperature of the components of the adapter pad 200 to increase the life of the components, as well to decrease the possible design constraints that might be necessary if the adapter pad 200 (or portions of the adapter pad 200) continuously operate with higher temperatures absent heat removal. This heat flow out of the adapter pad 200 may assist with the thermal design of the adapter pad 200 and the remainder of the truck system, which can have various design benefits such as broadening the possible elastomeric material choices, as well increasing the life of the elastomeric material by reducing its operating temperature, as other possible benefits.
In some embodiments, the adapter pad 200 can include additional features that can increase its ability to reduce heat in the adapter pad 200. For example, in some embodiments, first and/or second lateral flanges 216, 218 may include a portion that extends laterally from the side walls of the side frame pedestal area. During use, the laterally projecting flanges are in direct contact with airflow generated by the moving car, as opposed to the central portion which is insulated by the metal roller bearing adapter and the steel side frame pedestal region. These laterally projecting flanges can provide free surface area to transfer heat to atmosphere from the adapter pad 200. This can help dissipate heat from the hysteretic cycling of the elastomer, temperature increases of the roller bearing, and any other heat in the adapter pad 200. In certain embodiments, having first and/or second lateral flanges 216, 218 the operating temperature of the adapter pad system 198 can be reduced. For example under normal lateral shear cycling, as described below, the temperature differential between the lateral flanges 216, 218 and the center of the pad using a 5 mph constant velocity airflow over the first and second lateral flanges 216, 218 can be about 15 degrees Fahrenheit or in the range of about 5 degrees Fahrenheit to about 25 degrees Fahrenheit. Increased temperature transfer from the center of the pad to the lateral flanges can allow for further increased heat transfer to atmosphere, and therefore improved durability.
In some embodiments, one or both of the outer surface 224 of the central portion 226, or the inner surface 244 of the central portion 246 may include one or more of various surface features, and in some embodiments a pattern of surface features to make these surfaces non-smooth. For example, the upper surface may include one or more of bumps, ridges and valleys, roughened surfaces, “sticky” surfaces, and the like. These surfaces can be created through a number of methods including shot blasting surface, machining the surface, applying different substances such as different types of rubbers to the surface and the like. These surface features, when provided, may reduce the potential for lateral and/or longitudinal sliding, and/or relative rotation of the adapter pad with respect to the pedestal roof 152, which may improve adapter pad 200 dynamic loading and strength performance, and may also reduce localized heat generation within the adapter pad 800 due to friction between the adapter pad 200 and the pedestal roof 152, which must be removed from the adapter pad 200 (as discussed elsewhere herein). Similarly, a thermal barrier coating such as ceramic or porcelain can be applied to top or bottom plates 220, 240. Optionally, a thermal barrier plate can be used to thermally isolate the heat generated from the frictional sliding during the high amplitudes. This can be done in conjunction with the wear plate that is typically used with the steel-on-steel adapter plates. The plate can be formed such that an air gap is maintained and the contact areas located to the outside edges of the adapter.
The bottom plate 240 may be formed from a similar construction and materials as the top plate 220. Similarly, the outer surface 244 of the bottom plate can include surface treatments and coatings of an elastomeric material 265 as the top member.
In some embodiments the entire or a majority of adapter pad 200 can include a coating of an elastomeric material 265, as shown for example in
In some embodiments, it may be possible to use an electrically conductive additive in the elastomeric materials discussed herein to provide electrical conductivity and shunting ability through the top and bottom plates 220, 240. These additive particles may include materials such as nickel plated graphite, silver plated aluminum, or silver plated copper. The quantity of these additives may be as little as 0.5% of the total elastomer volume to provide sufficient electrical conductivity. Similarly, to create an electrical connection between the truck side frame to the adapter, a flexible conductor can be molded into the elastomeric pad connecting the upper pad plate to the bottom plate. The encasement of the conductor can protect the conductor from environmental corrosion. Its flexibility allows it to flex as the elastomeric (e.g., rubber) material strains. In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, the outer lateral edges 281, 282 of the lateral flanges of the top and bottom plates 220,240 are each aligned along the same vertical plane, as best shown in
Exemplary dimensions of the adapter pad 200 are shown and described in this application; however, other dimensions may be used for portions of the adapter pad, depending upon the fixed dimensions of the side frame and the bearings used with the particular railcar truck system.
The adapter pad 200 can, in some embodiments, as shown for example in FIGS. 3 and 11-11C, also include pads or grips on top and bottom plates 220, 240 of the adapter pad which can be configured to position the adapter pad 200 relative to the side frame pedestal roof 152 and the bearing adapter 199 and also engage and restrict movement of the adapter pad 200 relative to the pedestal roof 152 and the bearing adapter 199 which can focus movement (i.e. shear) of the adapter pad 200 to the elastomeric member 360. The assembly of the adapter pad 200 to the roller bearing adapter 199 can force the adapter pad 200 to be reasonably centered with regard to the roller bearing adapter 199, and the bearing by the use of the vertical shoulders 106 and including grips. Further, the adapter pad system 198 promotes the return of the adapter 200 and wheelset to a centered, or near zero force center position.
For example, the adapter pad 200 can include a first lateral adapter grip 270 disposed between the first vertical shoulder 106 of the adapter 199 and the first upturned region 248 of the bottom plate 240; and a second lateral adapter grip 271 disposed between the second vertical shoulder 106 of the adapter 199 and the second upturned region 250 of the bottom plate 240. The lateral adapter grips 270, 271 can run the entire longitudinal length of the adapter pad 200 or a portion of the longitudinal length of the adapter pad 200. In other embodiments, the lateral adapter grips 270, 271 can comprise a plurality of lateral adapter grips that run the entire lateral length of the adapter pad 200 or any portion thereof.
The lateral adapter pad grips 270, 271 can be integrally formed with the bottom plate 240, including with being integrally formed with any elastomeric coating 265 on the adapter pad 200. In other embodiments the lateral adapter pad grips 270, 271 can be integrally formed with the adapter 199. In still other embodiments, the lateral adapter pad grips 270, 271 can be attached to the adapter 199 and/or adapter pad 200 through use of adhesives or other known methods.
The adapter pad 200 can also include a first lateral side frame grip 272 disposed on the outer surface 224 of the first upturned region 228 of the top plate 220; and a second lateral side frame grip 273 disposed on the outer surface 224 of the second upturned region 230 of the top plate 220. In some embodiments, the first lateral side frame grip 272 can be disposed on the outer surface 224 of the first lateral flange 232 of the top plate 220; and the second lateral side frame grip 273 is disposed on the outer surface 224 of the second lateral flange 234 of the top plate 220. The lateral side frame grips 272, 273 can run the entire longitudinal length of the adapter pad 200 or a portion of the longitudinal length of the adapter pad 200. In other embodiments, the lateral adapter grips 272, 273 can comprise a plurality of lateral adapter grips that run the entire lateral length of the adapter pad 200 or any portion thereof.
The grips 270, 271, 272, 273 can be formed of an elastomeric material or any other suitable material and can in certain embodiments act to properly position the adapter pad 200 with respect to the side frame pedestal 152 and the adapter 199. Additionally, the first and second lateral adapter grips 270, 271 can be configured to reduce or eliminate sliding between the adapter 199 and the bottom plate 240 of the adapter pad 200. Similarly, the first and second lateral side frame grips 272, 273 can be configured to reduce or eliminate sliding between the outer surface 224 of the top plate 220 and the pedestal 152. This can in certain embodiments, reduce or eliminate sliding between the mating surfaces of adapter 199 and the adapter pad 200, and between mating surfaces of the side frame pedestal roof 199 and the adapter pad 200 during operation of the system. Additionally, this reduction of sliding between the contacting surfaces can in some embodiments reduce heat generated by any such sliding.
As discussed above, the grip features can significantly reduce relative motions between the horizontal surfaces of the adapter pad system by maintaining close-fitting contact between the vertical mating surfaces of the adapter pad assembly. Reduction of relative motions between the side frame pedestal 152 and the adapter pad 200 can improve the stiffness behavior of the adapter pad 200. As shown in
In certain embodiments, heat can be generated by movement of the adapter pad 200 relative to the roller bearing adapter 199 and the pedestal roof 152. This heat is generated by the hysteresis of the elastomer material cycling in shear displacement. As discussed above, excess heat can negatively affect the performance of the elastomeric member 360, and decrease the durability of the adapter pad. As shown in
As discussed above, and as shown primarily in
In general the elastomeric member 360 can be attached to the top and bottom plates 220, 240 through injection molding. Generally the top and bottom plates 220, 240 can be placed within the mold. In some embodiments, portions of the top and bottom plates 220, 240 can be coated with adhesive to allow the elastomeric member 360 to adhere to the plates. Additionally, in some embodiments, spacers can be placed within the mold in certain areas where the elastomeric material is not needed. Once setup is complete, elastomeric material can be heated and inserted into the mold, and the elastomeric material can flow throughout the mold cavity, adhering to the areas applied with adhesive. The elastomeric can then undergo vulcanization and/or curing.
The elastomeric member 360 may provide for dampening within the adapter pad 200, allow for discrete changes in stiffness and/or flexibility within the adapter pad 200, and to allow for differences in the dampening, stiffness, flexibility or other parameters within the different portions of the adapter pad 200 to allow for a suitable design.
As shown in
As best shown in
The central elastomeric portion 362 can be primarily disposed in the central portion 210, but in some embodiments can also be disposed in the first and second upturned regions 212, 214, as shown in
As best shown in
In some embodiments, the outer edge 374, 376 may be a longitudinal outer edge (374a, 376a) (i.e. may extend generally in the longitudinal direction when the adapter pad 200 is installed within a truck system) and may include a curved portion that is not in the same shape and alignment with the outer longitudinal edge of the top and/or bottom plates 220, 240. While the term “longitudinal outer edge” is used, this is meant to define the portion of the outer edge that extends between the opposed lateral edges 280, 282 (i.e. the two edges that extend laterally between the first and second lateral flanges 216, 218 and through the central portion 210), and as discussed herein may be curved with each portion of the curve including at least a vector component that faces in the lateral direction (i.e. perpendicular to the direction of motion of the truck that receives the adapter pad 200).
For example, at least a portion 374R, 376R of the outer edge 374, 376 may be formed with a continuous radius (R) with respect to a geometric center of the adapter pad, as annotated as “C” on
In some embodiments, the lateral edges 380, 382 and the longitudinal outer edges 374a, 376a, and any other edge of the elastomeric portion 360 may include an internally recessed contour 381, as best depicted in
As can be appreciated, and discussed elsewhere herein, the elastomeric member 360 compresses and deforms under load and the elastomeric material presses radially outward proximate to the outer edges. The internally recessed contour 381 minimizes or eliminates the deformation of the elastomeric member 360 beyond the nominal outer edge of the member 360, which can in certain embodiments enhance the fatigue life of the adapter pad 200.
The internally recessed contour 381 may include a first portion 383 that generally extends downward from a lower surface of the top plate 220, a second portion 385 that generally extends upward from the upper surface of the bottom plate 240, and a transition 384 therebetween. In some embodiments, one or both of the first and second portions 383, 385 may be planar (along a straight portion of the elastomeric portion) or linear (along curved portions of the elastomeric portion) (collectively a linear portion) that extends from the respective surface of the top and bottom plates 220, 240 at angles α, and β.
In some embodiments, the first and second portions 383, 385 may extend at the same relative angle, while in other embodiments, the first and second portions 383, 385 may extend at differing relative angles. In some embodiments, the angle(s) may be about 30 degrees to the neighboring surface of the top or bottom plate 220, 240, such as an angle within the range of between about 15 and about 45 degrees, inclusive of all angles within this range. As shown in
As best shown in
The hollow portion 372 can function to limit the bending stresses in the top and bottom plates 220, 240. The hollow portion 372 may be about 0.25 inches. At the about 0.25 inch motion range, the upturned regions of the top and bottom plate 220, 240 can engage and prevent further relative motion. This can put an upper limit on the elastomer strain in the lateral direction and the metal stress.
As will be discussed in more detail below, the elastomeric member 360 and particularly the outer elastomeric members 364, 366 can be configured in such a manner that the elastomer's rotational shear stresses, through a displacement of up to 41 milliradians, are no greater than the elastomer's lateral and longitudinal shear stresses through a displacement of up to 0.23 inches laterally and of up to 0.14 inches longitudinally. For example, the outer elastomeric members 364, 366 can be configured such that any point on curves 374R, 376R has less than or equal rotational shear displacement as the lateral or longitudinal shear displacements. And because shear strain is directly proportional to shear displacement, all points along the curve 374R, 376R can be subject to the same strain.
The elastomeric member 360 can be measured in a cross-sectional plane through about the center of the elastomeric material 360 centered between the inner surfaces of the top and bottom plates 220, 240. In embodiments where there are a plurality of elastomeric members each member can be measured separately and each member can be added together to determine the measurements of the entire elastomeric member 360. In some embodiments, the total shear width, or length in the lateral direction, of the elastomeric member 360 can be about 9.6 inches or in the range of about 6 inches to about 14 inches. Similarly, the total shear length, or length in the longitudinal direction, of the elastomeric member 360 can be about 6.9 inches or in the range of about 6 inches to about 10 inches. The composite shear perimeter, or perimeter of all portions of the elastomeric member can be about 51.70 inches or in the range of about 35 inches to about 75 inches. In some embodiments the total surface area of the elastomeric member 360 in the shear plane can be about 55.5 square inches or in the range of about 50 square inches to about 70 square inches. The total surface area of the elastomeric member 360 outside of the central portion can be about 15.5 square inches or in the range of about 5 square inches to about 30 square inches, or greater than 5 square inches. Thus, the surface area of the elastomeric member in the lateral flanges 216, 218 can be about 7.75 square inches each or in the range of about 2.5 square inches to about 15 square inches, or greater than 2.5 square inches.
As will be discussed in more detail below, the elastomer layers 364, 366 outside of the central area 210 can contribute to the overall stiffness of the adapter pad 200. For example in some embodiments, the elastomeric member 360 outside of the central area 210 can contribute about 15%, or in the range of about 5% to about 30%, of the total lateral and longitudinal stiffness of the adapter pad, and 33%, or in the range of about 15% to about 60%, of the rotational stiffness of the adapter pad 200.
As previously discussed, the elastomeric member 360 of the adapter pad 200 provides shear resistance during loading in the lateral, longitudinal, and rotational directions under a vertical load. This shear resistance is caused by relative movement between the top and bottom plates 220, 240 reacted through the elastomeric member 360. Simple shear strain is defined as d/t where d=displacement of the elastomeric member and t=thickness of the elastomeric member. In some embodiments, the shear strain can reach values greater than 100% under maximum displacement conditions. For example, in some embodiments, lateral strain achieves 110% or 120% or 130%. In some embodiments shear strain does not exceed 105%, 110%, 115%, or 120%, or 130% under maximum displacement.
To reduce the stresses in the elastomeric member 360 under maximum shear displacement, it can be beneficial to provide normal stress, or compression, to the elastomeric member 360 during shear loading. In some embodiments, vertical loading of adapter pads is transferred through the pedestal roof 152 of the side frame, to the central area 210. Additionally, although the top and bottom plates 220, 240 can contact the vertical shoulders of the adapter, in some embodiments, the top and bottom plates 220, 240 are flexible and the vertical load on the central region 210 is not transferred equally to the lateral flanges 216, 218 and can create a non-uniform distribution of the vertical load to the elastomeric member 360. This can result in less compression of the elastomeric member 360 outside of the area under the pedestal roof 152. Various methods can be used that can increase the normal stress or compression in the elastomeric member 360 outside of the pedestal roof 152, for example, in the lateral flanges 216, 218.
In embodiments, the elastomeric member 360, outside the pedestal roof 152 area can be compressed greater than 0.020 inches, or greater than 7% of the static thickness of the elastomeric member 360. In certain embodiments, pre-compression of this magnitude allows for improved fatigue life of the elastomeric member 360. Additionally, in embodiments discussed herein about 10 percent to 30 percent of vertical force can be distributed to each of the adapter pad lateral flanges 216, 218 when a vertical force is applied to the central portion 210 of the adapter pad 200. And in embodiments discussed herein the reaction of the vertical load at the vertical shoulders 106 can provide a vertical force greater than 3000 pounds to precompress the elastomeric member.
In some embodiments, as shown primarily in
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, as shown in
As best shown in
In some embodiments as shown in
In some embodiments, and as depicted in
In other embodiments depicted in
As best shown in
Additionally, other methods that can increase the compression of the elastomeric member 360 in the lateral flanges 216, 218 exist. For example, as shown in
In still other embodiments, for example, compression in the lateral flanges 216, 218 can be induced by manufacturing the lateral flanges 216, 218 of the top and bottom plates 220, 240 to angle towards each other and then mold the flanges to a generally parallel position. For example, the top plate 220 can be manufactured such that the lateral flanges 232, 234 are angled outward and downward and the bottom plate 240 lateral flanges 252, 254 are angled outward and upward prior to assembling the adapter pad 200. Thus, when originally manufactured, the lateral flanges of the top and bottom plates are not parallel and instead are angled towards each other. The plates 220, 240 are then assembled with the elastomeric section 360 and the lateral flanges 232, 234, 252, 254 are forced to elastically bend to a generally parallel alignment with each other. In some embodiments, this step can be accomplished, using an injection molding machine wherein the elastic member 360 is injected into the mold. Once the adapter pad is cured, there can be an elastic strain in the laterally projecting flanges that applies a normal load to the outer elastomer layers 364, 366 that can create compressive strain.
In still other embodiments, as shown in
As shown, for example, in
As shown in
To apply the upper or lower adapter pad compression shims 291, shown in
As discussed above, it has been determined through testing that the performance of the adapter pad system 198 is a function of the stiffness of the adapter pad 200. More specifically in certain embodiments, it has been determined that adapter pad performance, including design life, can be improved by increasing the stiffness of the adapter pad system 198 (measured in pounds of force per inch of deformation).
Physical measurement of the pad stiffness can be determined by cycling the adapter pad 200 in three principal directions: laterally, longitudinally, and rotationally; while withstanding a constant vertical load on the pad, typically of 35,000 pounds. The force to displace the pad relative to the distance the pad displaces is recorded throughout the measurement test. The data from the test can then be collected and plotted on force vs. displacement plots, an example of which is shown in
The target damping value for embodiments disclosed herein is 0.10 to 0.30 tan δ with a rubber/elastomeric material durometer target of 60 A to 80 A. Tan δ is a measure of the material damping when subjected to cyclic loads, defined as the ratio of the out-of-phase load (90 degrees on a sinusoidal load) to the in-phase load (0 degrees). Typical values for elastomers can be 0.04 to 0.35.
A more direct measure of the energy absorption for an adapter pad is the area of the hysteresis loop per cycle. For the embodiments described herein, the hysteretic energy absorption can be estimated by π3GTan δε2 where G is the shear modulus of ˜360 psi, Tan δ˜0.3 and ε the strain during hunting at ˜100%=1. At 4 Hz, the energy absorption would be about 4,070 in-lb./sec. A reasonable range may be +/−25%.
As discussed herein, certain embodiments include elastomeric member 360 (portions 364, and 366) in shear, outside of the area beneath the pedestal roof 152. In such embodiments, there can be more elastomeric material than can be used in shear than in a typical adapter pad. This can allow the adapter pad 200 to achieve increased stiffness without decreasing the shear thickness, or increasing elastomer durometer. Decreasing the shear thickness and/or increasing the elastomer durometer which can increase the strain and reduce the useful life of the pad. Thus, the adapter pad 200 can increase the stiffness of the adapter pad system 198 which can improve railcar overall performance while increasing the useful life of the adapter pad 200. The outer elastomer layers 364, 366 can increase the rotational stiffness of the adapter pad 200 by providing additional elastomer at a distance farther from the axis of rotation. In some embodiments, for example, the outer elastomeric layers 364, 366 can account for about 15% or about 10% to about 20%, or greater than 10% of the total lateral and longitudinal stiffness of the adapter pad 200, and can account for about 33% or about 25% to about 40%, or greater than 25% of the rotational stiffness of the adapter pad 200.
Embodiments disclosed herein can have high lateral and longitudinal stiffness, without having high force vs. displacement hysteresis. Hysteresis is proportional to energy dissipated through the displacement cycles, and can be lost in the form of heat or noise. Generally, the higher the hysteresis, the greater the temperature rise in the adapter pad 200, and the lower the fatigue life. Embodiments disclosed herein attain high stiffness of the adapter pad, while improving fatigue life by minimizing hysteresis and allowing the pad to displace to maximum magnitudes set by the AAR: 41 milliradians rotationally, 0.23 inches laterally, and 0.14 inches longitudinally.
Embodiments disclosed herein may require increasing amounts of force to displace the top plate 220 relative to the bottom plate 240 with higher magnitudes. The thickness, length, and amount of elastomeric material in the hollow section 372 can be adjusted to change the slope, and shape of the force vs. displacement graphs. In some embodiments, it is possible to have different stiffness properties for the elastomeric material of the pad located adjacent to the upturned adapter wings compared to the properties of the elastomeric material located in the central area of the adapter pad.
Using the above described test methods, exemplary measurements and testing results of embodiments disclosed herein are shown below in Table 2. It is understood that these embodiments are examples, and that other structural embodiments with other testing results can exist.
In one example an adapter pad system configured to be disposed between a wheelset roller bearing and side frame pedestal roof of a railcar truck is disclosed. The adapter pad system can include a roller bearing adapter having first and second vertical shoulders that project upward from a top surface of the adapter. The adapter pad system can also include an adapter pad configured to interface with the roller bearing adapter with a top plate having inner and outer surfaces, a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned region, and a second lateral flange projecting outward from the second upturned region; a bottom plate having inner and outer surfaces, a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned region, and a second lateral flange projecting outward from the second upturned region. The first and second laterally projecting flanges of the top plate and the bottom plate of the adapter pad system can be disposed above the vertical shoulders of the roller bearing adapter.
The roller bearing adapter of the adapter pad system can be cast or forged. The adapter pad can be engaged with the side frame and engaged with the roller bearing adapter. The top plate of the adapter pad can be engaged with the side frame such that movement between the top plate and the side frame is restricted. The bottom plate of the adapter pad can be engaged with the roller bearing adapter such that movement between the bottom plate and the roller bearing adapter is restricted. The roller bearing adapter can include longitudinal stops configured to restrict longitudinal movement of the bottom plate with respect to the roller bearing adapter. The vertical shoulders can be configured to restrict lateral movement of the bottom plate with respect to the roller bearing adapter. The roller bearing adapter top surface can include a crowned surface. The longitudinal stops and vertical shoulders can be configured to restrict rotational movement of the bottom plate with respect to the roller bearing adapter. The roller bearing adapter can be symmetrical about a lateral centerline. The roller bearing adapter can be symmetrical about a longitudinal centerline. The top plate of the roller bearing adapter can be continuous. The bottom plate of the roller bearing adapter can be continuous.
The adapter pad system can include an elastomeric member disposed between the inner surfaces of the top plate and the bottom plate. The elastomeric member disposed between the top plate and the bottom plate can be a plurality of elastomeric members. The plurality of elastomeric members can include a first outer elastomeric member disposed between the first lateral flanges of the top and bottom plates, a second outer elastomeric member disposed between the second lateral flanges of the top and bottom plates, and a central elastomeric member disposed between the central portion of the top and bottom plates. A first hollow portion can be disposed between the central elastomeric member and the first outer elastomeric member and a second hollow portion can be disposed between the central elastomeric member and the second outer elastomeric member. The first and second hollow portions can be about 0.25 inches wide. The first and second hollow portions can be configured to limit bending stresses in the top and bottom plates. The outer elastomeric members can be in compression. The thickness of the outer elastomeric members can be compressed at least 0.020 inches from a static state. The thickness of the outer elastomeric members can be compressed at least 7% from a static state. The first outer elastomeric member, second outer elastomeric member, and central elastomeric member can each be substantially planar and each can be substantially horizontal when the adapter pad is disposed below a side frame pedestal roof of a railcar truck. The elastomeric material can be positioned normal to the direction of lateral displacement to increase compression stiffness. The elastomeric material can be positioned normal to the direction of longitudinal displacement to increase compression stiffness. The elastomeric material can be positioned normal to the direction of rotational displacement to increase compression stiffness. The elastomeric material can be positioned normal to the direction of vertical displacement to increase compression stiffness.
The surface area of the first outer elastomeric member at a cross-sectional plane through the first outer elastomeric member centered between the inner surfaces the top and bottom plates can be greater than 2.5 square inches. The surface area of the second outer elastomeric member at a cross-sectional plane through second outer elastomeric member in a plane centered between the inner surfaces of the top and bottom plates can be greater than 2.5 square inches. The combined surface area of the first and second outer elastomeric members at cross-sectional planes through the first and second outer elastomeric members in planes centered between the inner surfaces of the top and bottom plates can be greater than 5 square inches. The combined surface area of the first and second outer elastomeric members at cross-sectional planes through the first and second outer elastomeric members in planes centered between the inner surfaces of the top and bottom plates can be at least 10 percent of the surface area of the central elastomeric member at a cross-section plane through the center of the central elastomeric member in a centered between the inner surfaces of the top and bottom plates.
The central elastomeric member can define a plurality of gaps that establish a plurality of discontinuities within the elastomeric member disposed between the central portion of the top plate and the central portion of the bottom plate. The plurality of gaps can be a thickness less than a total distance between the top plate and the bottom plate, with a portion of the elastomeric member being vertically disposed with respect to the one or more of the plurality of gaps and contacting one or both of the top and bottom plates.
The central elastomeric member can define an outer edge, wherein one or more portions of the outer edge is curved from a top view. At least a portion of the outer edge of the central elastomeric portion can define an internally recessed contour. The first and second outer elastomeric members can define an outer edge, wherein one or more portions of the outer edge is curved from a top view. One or more portions of outer edges of elastomeric members can include a continuous radius measured from a center point of the central portion of the top plate. Any edge of the elastomeric member can define an internally recessed contour.
One or both of the first and second outer elastomeric members can define an outer edge, wherein one or both of the first and second lateral flanges of the top and bottom plates extend outward past at least a portion of the outer edge within the respective first and second lateral flanges.
The adapter pad can include an elastomeric support disposed between the outer surfaces of the first and second lateral flanges of the bottom plate and the vertical shoulders of the roller bearing adapter.
At least a portion of an outer edge of the elastomeric members can define an internally recessed contour. The internally recessed contour can be defined by a first linear portion that extends from proximate to the inner surface of the top plate and a second linear portion that extends from proximate to the inner surface of the bottom plate. The first and second linear portions can be connected with a transition as it extends between the first and second linear portions. The first and second linear portions can each extend from the neighboring respective top or bottom plate at an angle within the range of about 25 degrees to about 35 degrees to a plane through the surface of the respective top or bottom plate from which the respective linear portion extends.
The first and second outer elastomeric members can be the same or greater thickness than the central elastomeric member. The thickness of the first and second outer elastomeric members can be within the range of about 0.15 inches to about 0.30 inches. The thickness of the central elastomeric member can be within the range of about 0.15 inches to about 0.25 inches. The thickness of the adapter pad can be within the range of about 0.4 inches to about 0.8 inches.
The adapter pad system can also include an elastomeric layer disposed above an outer surface of the top plate and/or can include an elastomeric layer disposed below an outer surface of the bottom plate. The elastomeric layer can cover all or portions of the outer surface of the adapter pad. The top and bottom plates of the adapter pad can be of non-uniform thickness. The top and bottom plates can be of uniform thickness. The top plate can have a non-uniform thickness. The top plate can have a uniform thickness. The bottom plate can have a non-uniform thickness. The bottom plate can have a uniform thickness.
The adapter pad system can be configured to return to a neutral or central position within the side frame pedestal after removal of a load placed thereon.
The first and second lateral flanges of the top plate can include a planar outer surface that can be parallel to the outer surface of the central portion of the top plate.
The inner surfaces of each of the first and second upturned regions of the first and second plates of the adapter pad can include a planar portion. The inner surfaces of each of the first and second upturned regions of the first and second plates of the adapter pad can include a curved portion. The first and second upturned regions of the first and second plates of the adapter pad can include at least a portion that extends at an obtuse angle to a plane through the outer surface of the central portion of the top plate.
The first and second lateral flanges of the top plate of the adapter pad can include exposed outer surfaces when the adapter pad contacts a side frame pedestal. The first and second lateral flanges can contact air outside of the envelope of the side frame at the pedestal opening. The first and second lateral flanges can be configured to reduce heat of the adapter pad. The first and second lateral flanges can be configured to reduce heat of the adapter pad system.
The adapter pad can include a lateral length of the central portion that can be equal to the distance between the sidewalls of at the pedestal roof surface. The lateral length of the central portion can be about 0.125 inches greater than the length between the side walls of the side frame at the pedestal roof surface. The overall lateral length of the top plate can be at least 7.5 inches.
The adapter pad system can also include a first lateral adapter grip disposed between an inside surface of the first vertical shoulder of the roller bearing adapter and the first upturned region of the bottom plate; and a second lateral adapter grip disposed between an inside surface of the second vertical shoulder of the roller bearing adapter and the second upturned region of the bottom plate. The first and second lateral adapter grips can be formed of an elastomeric material. The first and second lateral adapter grips can be configured to limit sliding or relative movement between the roller bearing adapter and the outer surface of the bottom plate of the adapter pad. The first and second lateral adapter grips can be configured to center the bottom plate of the adapter pad on the roller bearing adapter.
The adapter pad system can also include a first lateral side frame grip disposed on the outer surface of the first upturned region of the top plate; and a second lateral side frame grip disposed on the outer surface of the second upturned region of the top plate. The first lateral side frame grip can be disposed between the outer surface of the first lateral flange of the top plate and a side frame pedestal, and the second lateral side frame grip can be disposed between the outer surface of the second lateral flange of the top plate and a side frame pedestal. The first and second lateral side frame grips can be formed of an elastomeric material. The first and second lateral side frame grips can be configured to limit sliding or relative movement between an outer surface of the top plate and the side frame immediately above the pedestal area.
In some examples, the adapter pad system can be configured to restrict the elastomer temperatures below the degradation temperature of the specific elastomeric and/or adhesive material used in pad construction. The adapter pad system can also be configured to reduce melting of the elastomeric member.
The adapter pad system can include a first adapter compression shim disposed between an upper surface of the first vertical shoulder of the roller bearing adapter and the outer surface of the first lateral flange of the bottom plate. The adapter pad system can also include a second adapter compression shim is disposed between an upper surface of the second vertical shoulder of the roller bearing adapter and the outer surface of the second lateral flange of the bottom plate. The thickness of the first and second adapter compression shims can be within the range of about 0.06 inches to about 0.18 inches.
The adapter pad can include a lower first adapter pad compression shim disposed between the elastomeric member and the first lateral flange of the bottom plate. The adapter pad can also include a second lower adapter pad compression shim is disposed between the elastomeric member and the second lateral flange of the bottom plate. The thickness of the first and second lower adapter pad compression shims can be within the range of about 0.06 inches to about 0.18 inches.
The adapter pad can include a first upper adapter pad compression shim disposed between the first lateral flange of the top plate and the first outer elastomeric member. The adapter pad can also include a second upper adapter pad compression shim is disposed between the second lateral flange of the top plate and the second outer elastomeric member. The thickness of the first and second upper adapter pad compression shims can be within the range of about 0.06 inches to about 0.18 inches.
The compression shims can be configured to provide at least 3000 pounds of vertical compressive load into the outer elastomeric members when a vertical load of 35,000 pounds is applied to the central portions of the adapter pad. The compression shims can be rectangular. The compression shims can have a rectangular cross-section shape, a curved cross-sectional shape, a triangular cross-sectional shape, or a trapezoidal cross-sectional shape. The compression shims can include a raised portion. The compression shims can include a hollow portion. The compression shims can comprise a plurality of compression shims.
The lateral flanges of the adapter pad can be vertically supported by the vertical shoulders of the roller bearing adapter. About 10 percent to 30 percent of vertical force can be distributed to each of the adapter pad lateral flanges when a vertical force is applied to the central portions of the adapter pad. The reaction of the vertical load at the vertical shoulders can provide a vertical force of at least 3000 pounds to precompress the elastomeric member.
The combined top plate, bottom plate, and elastomeric member of the adapter can pad provide a longitudinal stiffness that can be at least 45,000 pounds per inch through a longitudinal displacement of the top plate relative to the bottom plate of up to 0.139 inches from a central position, when a vertical load of 35,000 pounds is applied to the central portions of the adapter pad. The longitudinal hysteresis of the adapter pad system can be less than about 1500 lbs.
The combined top plate, bottom plate, and elastomeric member of the adapter pad can provide a lateral stiffness that can be at least 45,000 pounds per inch through a lateral displacement of the top plate relative to the bottom plate of up to 0.234 inches from a central position, when a vertical load of 35,000 pounds is applied to the central portions of the adapter pad. The lateral displacement hysteresis of the adapter pad system can be less than about 6,000 lbs.
The top plate, bottom plate, and elastomeric member of the adapter pad can provide a rotational stiffness that can be at least 250,000 pound*inches per radian of rotation through a rotational displacement of the top plate relative to the bottom plate of up to 41 milliradians from a central position when a vertical load of 35,000 pounds is applied to the central portions of the adapter pad. The twist hysteresis can be less than about 16,000 lbs.*in.
The top plate, bottom plate, and elastomeric member of the adapter pad can provide a vertical stiffness that can be at least 5,000,000 pounds per inch through a vertical displacement of 0.05 inches. Vertical displacement can be non-linear and can range from 5,000,000 pounds per inch to 30,000,000 pounds per inch depending on variations in durometer, thickness tolerances, and non-linearity of the compression stiffness.
The combined top plate, bottom plate, and elastomeric member of the adapter pad can provide a lateral stiffness that is within about ten percent of a longitudinal stiffness when a vertical load is applied to the central portions of the adapter pad.
The combined top plate, bottom plate, and elastomeric member of the adapter pad can provide a lateral strain in the elastomeric member that is substantially similar throughout the elastomeric member when a vertical load is applied to the central portions of the adapter pad.
The combined top plate, bottom plate, and elastomeric member of the adapter pad can provide a longitudinal strain in the elastomeric member that is substantially similar throughout the elastomeric member when a vertical load is applied to the central portions of the adapter pad.
The combined top plate, bottom plate, and elastomeric member of the adapter pad can provide a rotational strain in the elastomeric member that can be substantially similar throughout the elastomeric member when a vertical load is applied to the central portions of the adapter pad.
The combined top plate, bottom plate, and elastomeric member of the adapter pad can provide a rotational strain that is less than or equal to the lateral strain at any point in the elastomeric member when a vertical load is applied to the central portions of the adapter pad.
The combined top plate, bottom plate, and elastomeric member of the adapter pad can provide shear strain that does not exceed 120% under maximum displacement
The thickness of the central portion of the bottom plate of the adapter pad can be non-uniform. The thickness of the central portion of the bottom plate can be greater at the lateral edges than at the center of the central portion.
The thickness of the elastomeric member disposed between the central portions of the top and bottom plate can be substantially uniform.
In another example a method for forming an adapter pad can include providing a top plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned lateral portion, and a second lateral flange projecting outward from the second upturned lateral portion; providing a bottom plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned lateral portion, and a second lateral flange projecting outward from the second upturned lateral portion; inserting an elastomeric member between the top plate and the bottom plate wherein a first outer elastomeric member is disposed between the first lateral flanges, a second outer elastomeric member is disposed between the second lateral flanges, and a central elastomeric member is disposed between the central portions; and compressing the first lateral flange of the top plate and the first lateral flange of the bottom plate towards each other; and compressing the second lateral flange of the top plate and the second lateral flange of the bottom plate towards each other.
The compressing steps can create deformation of the first and second lateral flanges after the molding operation is complete. This deformation can result in preloading of the outer elastomeric members. The compressing steps can apply greater than 3000 pounds force of compression in the outer elastomer members. The compressing steps can compress the outer elastomeric member at least 0.02 inches of a static thickness of the outer elastomeric members. The compressing steps compress the outer elastomeric member greater than 7 percent of a static thickness of the outer elastomeric members.
In another example a method for forming an adapter pad can include providing a top plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward and downward from the first upturned lateral portion, and a second lateral flange projecting outward and projecting downward from the second upturned lateral portion; providing a bottom plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward and upward from the first upturned lateral portion, and a second lateral flange projecting outward and projecting upward from the second upturned lateral portion; inserting an elastomeric member between the top plate and the bottom plate; and compressing the top plate and the bottom plate such that the lateral portions of the top and bottom plates are substantially parallel.
The compressing steps can compress the outer elastomeric member at least 0.02 inches of a static thickness of the outer elastomeric members. The compressing steps can compress the outer elastomeric member greater than 7 percent of a static thickness of the outer elastomeric members.
In another example a method for forming an adapter pad can include providing a top plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned lateral portion, and a second lateral flange projecting outward from the second upturned lateral portion; providing a bottom plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned lateral portion, and a second lateral flange projecting outward from the second upturned lateral portion; inserting a first outer elastomeric member between the first lateral flange of the top plate and the first lateral flange of the bottom plate; and inserting a second outer elastomeric member between the second lateral flange of the top plate and the second lateral flange of the bottom plate; and inserting a central elastomeric member between the central region of the top plate and the central region of the bottom plate
The thickness of the central elastomeric member can be less than or equal to the thickness of the first and second outer elastomeric members.
In another example a method for forming an adapter pad can include providing a top plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned lateral portion, and a second lateral flange projecting outward from the second upturned lateral portion; providing a bottom plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned lateral portion, and a second lateral flange projecting outward from the second upturned lateral portion; inserting a first outer elastomeric member between the first lateral flange of the top plate and the first lateral flange of the bottom plate; and inserting a second outer elastomeric member between the second lateral flange of the top plate and the second lateral flange of the bottom plate; and inserting a central elastomeric member between the central region of the top plate and the central region of the bottom plate; compressing the first and second lateral flanges of the top plate and the bottom plate together; and bonding the top plate to the first outer elastomeric member, the second outer elastomeric member, and the central elastomeric member.
The thickness of the central elastomeric member can be less than the thickness of the first and second outer elastomeric members.
The compressing steps can compress the outer elastomeric member at least 0.02 inches of a static thickness of the outer elastomeric members. The compressing steps compress the outer elastomeric member greater than 7 percent of a static thickness of the outer elastomeric members.
In another example, an adapter pad system for use between a railcar side frame pedestal and a rail car axle roller bearing adapter is disclosed. The side frame pedestal can define a first outer side, an opposite second outer side, and a pedestal roof located and extending between the first outer side and the second outer side. The adapter pad system can include a bearing adapter defining a bottom surface and a top surface, the bottom surface mounted to the railcar axle roller bearing, the top surface defining opposing first and second vertical shoulders that project upwardly from the top surface, on either side of the side frame just above the pedestal roof. The adapter pad system can include an adapter pad configured to interface with the bearing adapter including a top plate having inner and outer surfaces, a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region; and a bottom plate having inner and outer surfaces, a central portion, first and second upturned regions projecting upwardly from opposite edges of the central portion, a first lateral flange projecting outwardly from the first upturned region, and a second lateral flange projecting outwardly from the second upturned region.
The top plate and bottom plate central portions can be disposed beneath the pedestal roof of the side frame pedestal, and the first and second laterally projecting flanges of the top plate and the bottom plate can be disposed above the vertical shoulders of the roller bearing adapter and outside of the pedestal roof of the side frame pedestal and along the first and second outer sides of the side frame pedestal.
In another example, an adapter pad configured to be disposed between an adapter and a side frame pedestal roof of a railcar truck is disclosed. The adapter pad can include a top plate having inner and outer surfaces, a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned region, and a second lateral flange projecting outward from the second upturned region; and a bottom plate having inner and outer surfaces, a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned region, and a second lateral flange projecting outward from the second upturned region.
The outer surfaces of the first and second laterally projecting flanges of the bottom plate can be vertically higher than the outer surface of the central portion of the top plate.
In another example, a method for forming an adapter pad can include providing a top plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned lateral portion, and a second lateral flange projecting outward from the second upturned lateral portion; providing a bottom plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned lateral portion, and a second lateral flange projecting outward from the second upturned lateral portion; inserting a first outer elastomeric member between the first lateral flange of the top plate and the first lateral flange of the bottom plate; inserting a second outer elastomeric member between the second lateral flange of the top plate and the second lateral flange of the bottom plate; inserting a central elastomeric member between the central region of the top plate and the central region of the bottom plate; vulcanizing or curing the elastomeric members; inserting a first compression shim in the first lateral flange; and inserting a second compression shim in the second lateral flange. In some embodiments compression shims can be added after vulcanization or curing of the elastomer is complete.
In another example, a method for forming an adapter pad can include, providing a top plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned lateral portion, and a second lateral flange projecting outward from the second upturned lateral portion; providing a bottom plate having a central portion, first and second upturned regions projecting upward from opposite edges of the central portion, a first lateral flange projecting outward from the first upturned lateral portion, and a second lateral flange projecting outward from the second upturned lateral portion; inserting a first outer elastomeric member between the first lateral flange of the top plate and the first lateral flange of the bottom plate; and inserting a second outer elastomeric member between the second lateral flange of the top plate and the second lateral flange of the bottom plate; and inserting a central elastomeric member between the central region of the top plate and the central region of the bottom plate; curing the elastomeric members; inserting a first compression shim in the first lateral flange; and inserting a second compression shim in the second lateral flange. The steps of inserting the first and second compression shims can be performed after curing the elastomeric members.
The compressing steps can compress the outer elastomeric member at least 0.02 inches of a static thickness of the outer elastomeric members. The compressing steps compress the outer elastomeric member greater than 7 percent of a static thickness of the outer elastomeric members.
In another example, an adapter pad system for use between a railcar side frame pedestal and a rail car axle roller bearing is disclosed. The side frame pedestal can define a first outer side, an opposite second outer side, and a pedestal roof located and extending between the first outer side and the second outer side. The adapter pad system can include a bearing adapter defining a bottom surface and a top surface, the bottom surface mounted to the railcar axle roller bearing. The adapter pad can be configured to interface with the bearing adapter and can further include a top plate having inner and outer surfaces, a central portion, and outer portions; a bottom plate having inner and outer surfaces, a central portion, and outer portions, and an elastomeric member having a central portion and outer portions disposed between the inner surfaces of the top and bottom plates.
The top plate and bottom plate central portions can be disposed beneath the pedestal roof of the side frame pedestal, and the outer portions of the top and bottom plate can be disposed outside of the pedestal roof of the side frame pedestal.
The adapter pad system can include a continuous top plate. The adapter pad system can include a continuous bottom plate.
The combined surface area of the outer portions of the elastomeric member at cross-sectional planes through the outer portions of the elastomeric members in planes centered between the inner surfaces of the top and bottom plates can be greater than 5 square inches.
The combined surface area of the outer portions of the elastomeric members at cross-sectional planes through the outer portions of the elastomeric members in planes centered between the inner surfaces of the top and bottom plates can be at least 10 percent of the surface area of the central portion of the elastomeric member at a cross-sectional plane through the center of the central portion of the elastomeric member in a plane centered between the inner surfaces of the top and bottom plates.
The central portion of the elastomeric member can be in a different plane than the outer portions of the elastomeric member. The central portion of the elastomeric member can be in a parallel plane with the outer portions of the elastomeric member. The outer portions can be vertically spaced from the central portions.
The top plate can be engaged with the side frame, and the bottom plate can be engaged with the roller bearing adapter.
In another example, an adapter pad system for use between a railcar side frame pedestal and a rail car axle roller bearing is disclosed. The side frame pedestal can define a first outer side, an opposite second outer side, and a pedestal roof located and extending between the first outer side and the second outer side. The adapter pad system can include a bearing adapter defining a bottom surface and a top surface, the bottom surface mounted to the railcar axle roller bearing. The adapter pad system can include an adapter pad configured to interface with the bearing adapter that includes a top plate having inner and outer surfaces, a central portion, and outer portions; a bottom plate having inner and outer surfaces, a central portion, and outer portions, and an elastomeric member having a central portion and outer portions disposed between the inner surfaces of the top and bottom plates.
The top plate and bottom plate central portions can be disposed beneath the pedestal roof of the side frame pedestal, and the outer portions of the top and bottom plate can be disposed outside of the pedestal roof of the side frame pedestal.
The outer portions of the top and bottom plates can be configured to accept about 10 percent to 30 percent of vertical force applied to the central portions.
The outer portions of the adapter pad can be supported by vertical shoulders of the bearing adapter.
In another example, a roller bearing adapter configured to be disposed between a roller bearing and an adapter pad of a railcar truck is disclosed. The roller bearing adapter can have a bearing surface, an adapter crown surface, a longitudinal centerline, and first and second vertical shoulders that project upward from the pedestal crown surface of the adapter. The thickness of the center section of the roller bearing adapter can be less than 0.75 inches as measured at the longitudinal centerline from a bearing surface to a pedestal crown surface of the adapter.
The thickness of the roller bearing adapter can be between approximately 0.60 and 0.75 inches as measured at the longitudinal centerline from a bearing surface to a pedestal crown surface of the adapter. The width of the vertical shoulders can be at least 0.5 inches.
The roller bearing adapter can have a cross-sectional moment of inertia of a cross-section at the longitudinal centerline of the roller bearing adapter around a lateral axis about 5.2 inches above a center axis of an axle that is about 1.4 in4, or in the range of about 1.0 to about 2.0 in4. The lateral axis can be between about 5.0 inches and 5.5 inches from the center axis of the axle. The roller bearing adapter can have a cross-sectional moment of inertia of a cross-section at the longitudinal centerline of the roller bearing adapter around a vertical axis at the center of the adapter that can be about can be about 86.8 in4, or in the range of about 50 to about 100 in4.
The present invention is disclosed above and in the accompanying drawings with reference to a variety of examples. The purpose served by the disclosure, however, is to provide examples of the various features and concepts related to the invention, not to limit the scope of the invention. The terms and descriptions used herein are set forth by way of illustration only and are not meant as limitations. One skilled in the relevant art will recognize that numerous variations and modifications may be made to the examples described above without departing from the scope of the present invention. For example, the steps of the methods need not be executed in a certain order, unless specified, although they may have been presented in that order in the disclosure.
This patent application claims the benefit of U.S. Provisional Patent Application No. 61/921,961, filed Dec. 30, 2013, entitled Railcar Truck Roller Bearing Adapter-Pad Systems, and U.S. Provisional Patent Application No. 62/065,438, filed Oct. 17, 2014, entitled Railcar Truck Roller Bearing Adapter-Pad Systems which are incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62065438 | Oct 2014 | US | |
| 61921961 | Dec 2013 | US |
