Conventional freight railroad cars in North America and other parts of the world typically include a car body and two spaced apart trucks. The car body or car body under frame typically includes two spaced apart center plates that respectively rest on and are rotatably or swivelly received by bolster bowls of the two trucks. The trucks rollingly support the car body along railroad tracks or rails. Each truck typically has a three piece truck configuration that includes two spaced apart parallel side frames and a bolster. The side frames extend in the same direction as the tracks or rails, and the bolster extends transversely or laterally to the tracks or rails. The bolster extends laterally through and between and is supported by the two spaced apart side frames. Each side frame typically defines a center opening and pedestal jaw openings on each side of the center opening. Each end of each bolster is typically supported by a spring group positioned in the center opening of the side frame and supported by the lower portion of the side frame that defines the center opening.
Each truck also typically includes two axles that support the side frames, four wheels, and four roller bearing assemblies respectively mounted on the ends of the axles. The truck further typically includes four bearing adapters respectively positioned on each roller bearing assembly in the respective pedestal jaw opening below the downwardly facing wall of the side frame that defines the top of the pedestal jaw opening. The wheel sets of the truck are thus received in bearing adapters placed in leading and trailing pedestal jaws in the side frames, so that axles of the wheel sets are generally parallel to each other. The bearing adapters permit relatively slight angular displacement of the axles. The spring sets or groups permit the bolster to move somewhat with respect to the side frame, about longitudinal or horizontal, vertical, and transverse axes (and combinations thereof).
Directions and orientations herein refer to the normal orientation of a railroad car in use. Thus, unless the context clearly requires otherwise, the “longitudinal” axis or direction is substantially parallel to straight tracks or rails and in the direction of movement of the railroad car on the track or rails in either direction. The “transverse” or “lateral” axis or direction is in a horizontal direction substantially perpendicular to the longitudinal axis and the straight tracks or rails. “Vertical” is the up-and-down direction, and “horizontal” is a plane parallel to the tracks or rails including the transverse and longitudinal axes. A truck is considered “square” when its wheels are aligned on parallel rails and the axles are parallel to each other and perpendicular to the side frames. The “leading” side of the truck means the first side of a truck of a railroad car to encounter a turn; and the “trailing” side is opposite the leading side.
Existing trucks do not fully address the ever increasing and expected future demands for freight railroad car truck performance in the railroad industry. More specifically, while the various current known and commercially available three piece truck configurations meet current Association of American Railroads (“AAR”) specifications, enhanced specifications are being developed by the AAR and it is expected that the current three piece truck configurations may not meet these new AAR specifications. These AAR enhanced specifications set forth or codify these continuing and ongoing demands in the railroad industry for improved freight railroad car truck performance to: (a) reduce railroad car component wear and damage such as wheel wear and damage; (b) reduce rolling resistance; (c) reduce fuel consumption; (d) reduce the need for and thus cost of railroad track or rail repair (including reducing the cost of rail and tie maintenance); (e) reduce truck hunting and improve high speed stability (“HSS”) for both empty and loaded railroad cars; and (f) improve curving performance for both empty and loaded railroad cars.
Ideally, on straight tracks or straight rails, a three piece truck with parallel side frames and parallel wheel set axles perpendicular to the side frames (i.e., a perfectly “square” truck) rolls without inducing lateral or transverse forces between the wheel tread and the rail. However, at higher speeds, even minor imperfections or perturbations in the tracks or rails or in the equipment can lead to a condition known as “hunting” that refers to a yawing or oscillating lateral movement of the wheel sets along the tracks or rails that causes the railroad car to move side-to-side on the tracks or rails. More than minor imperfections or perturbations in the tracks or rails or in the railroad car equipment or components can lead to greater truck hunting even at lower speeds. Hunting tends to increase wheel wear and damage, increase fuel consumption, increase the need for railroad track or rail repair, and decrease HSS. In certain instances, hunting has also led to derailments, damage to the lading, and damage to the freight railroad cars.
Curved railroad tracks or rails pose a different set of challenges for the standard three-piece truck. When a railroad car truck encounters a curve or turn, the distance traversed by the wheels on the outside of the curve is greater than the distance traversed by wheels on the inside of the curve, resulting in lateral and longitudinal forces between the respective wheels and the tracks or rails. These wheel forces often cause the wheel set to turn in a direction opposing the curve or turn. On trucks with insufficient rigidity, this can result in a condition variously known as “warping,” “lozenging,” “parallelogramming,” and/or “unsquaring,” wherein the side frames remain parallel, but one side frame moves forward with respect to the other side frame. This condition is referred to herein as warping for brevity.
Another known issue relates to various known three piece railroad truck suspensions that have side frames with flat rectangular surfaces against which friction wedges are pressed to produce frictional (i.e., Coulomb) damping to control vertical bounces and other oscillatory modes. Normally, significant clearance exists between the side frame's column face and nearby surfaces of the bolster to enable assembly and proper relative motion during use. This clearance is undesirable in that it enables the truck assembly to become warped or change shape from the intended parallel and perpendicular arrangement (i.e., to undergo warping).
Such warping (alone or in combination with hunting) can cause increased wear on the tracks or rails and railroad car truck components or equipment. Such warping (alone or in combination with hunting) also tends to increase rolling resistance that increases railroad car fuel consumption, decreases railroad car efficiency, and increases railroad engine pollution.
Accordingly, there is a need to meet these ongoing demands in the railroad industry for improved freight railroad car truck performance that reduces, inhibits, and/or minimizes warping.
Various embodiments of the present disclosure provide a new railroad car, and more particularly a new railroad car truck with warp restraints that minimizes or solves the above warping related problems.
In various embodiments, the railroad car truck with warp restraints of the present disclosure includes a first side frame, a second side frame, a bolster, and a plurality of warp restraints. In various embodiments, each warp restraint includes a first inner bearing race connected to or integrally formed as part of the bolster, a second opposing inner bearing race connected to or integrally formed as part of the side frame, and a roller positioned in a channel formed by and between these first and second opposing bearing races. In various embodiments, the warp restraints including the independent rollers are each positioned at the inner and outer edges of the two column faces of each side frame to co-act to reduce, inhibit, or minimize warping of the railroad car truck of the present disclosure. More specifically, in various embodiments, the railroad car truck of the present disclosure has eight such warp restraints including: (1) a first plurality or set of warp restraints at a first end portion of the bolster and at the first side frame; and (2) a second plurality or set of warp restraints at a second end portion of the bolster and at the second side frame. In the first plurality of warp restraints, each first warp restraint includes a first inner bearing race connected to or integrally formed with a first end portion of the bolster, a second opposing inner bearing race connected to or integrally formed with the first side frame, and a roller positioned in a channel formed by and between these first and second opposing bearing races. In the second plurality of warp restraints, each second warp restraint includes a first inner bearing race connected or integrally formed with a second end portion of the bolster, a second opposing inner bearing race connected to or integrally formed with the second side frame, and a roller positioned in a channel formed by and between these first and second opposing bearing races. The present disclosure contemplates that the rollers may be of different shapes, sizes, and materials as further discussed in more detail below.
The rollers interact with the respective opposing bearing races to apply opposing forces to the side frames and bolster to reduce, inhibit, or minimize warping. More specifically, when the bolster moves from a square or perpendicular position relative to the side frames (or relative to each respective side frame), the respective warp restraints independently and in various groups or combinations co-act to apply opposing biasing forces to the bolster and the side frames to cause the bolster and/or side frames to move in the respective opposing direction and return to their normal square, perpendicular, or substantially perpendicular positions relative to each other, and thus co-act to reduce, inhibit, or minimize warping as further described below. It should also be appreciated that although the rollers or warp restraints of the present disclosure are not primarily intended to produce resistance against other directional movements of the bolster relative to the side frames, in various circumstances and embodiments, the warp restraints of the present disclosure can act or co-act to permit certain directional movements and act or co-act to reduce, inhibit, or minimize certain other directional movements alone or in combination with other components of the railroad car truck (such as friction wedges that provide vertical dampening or gibs that provide lateral restraint).
Other objects, features, and advantages of the present disclosure will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts.
Referring now to the drawings and particularly to
Referring now to
In this illustrated example embodiment of the present disclosure, as best shown in
It should be appreciated that each of the warp restraints 100, 200, 300, 400, 500, 600, 700, and 800 can be generally identical (except for positioning and arrangement of their connectors to, connections with, or formations with the side frames and the bolster). Therefore, warp restraint 100 is primarily discussed in further detail below. However, it should be appreciated that these warp restraints do not need to be identical and can vary based on the respective positions and connections to or formations with the side frames and the bolster. For example, the two bearing races of any single warp restraint may be different and specifically may have walls with different angles. This is somewhat illustrated when the example warp restraints of
More specifically, example warp restraint 100 includes a first inner bearing race 110 integrally formed with the first end portion of the bolster 40, a second opposing outer bearing race 140 integrally formed with the first side frame 60, and a roller 180 positioned in a channel formed by and between the first and second opposing bearing races 110 and 140. It should be appreciated that the first inner bearing race 110 may be connected to the bolster 40 by a suitable first bearing race connector (not shown). It should also be appreciated that the second inner bearing race 140 may be connected to the bolster 40 by a suitable second bearing race connector such as connector 104 (best shown in
As best shown in
Similarly, as best shown in
The first inner bearing race 110 and the second opposing outer bearing race 140 also form a V-shaped channel (when viewed from the side as best shown in
In certain embodiments, the slope of the bottom surfaces 146 of the outer bearing races 140, for example, may be at an angle C (shown in
It should be appreciated that in various embodiments, one or more members (that may or may not include one or more springs) will be employed to maintain the roller in the V-shaped channel.
It should also be appreciated that in various embodiments, one or more of the walls of the bearing races may be formed with one or more protrusions or inwardly protruding members employed to maintain the roller in the V-shaped channel.
It should also be appreciated that in other alternative embodiments, the channel is inverted such that it is wider at the bottom. In such alternative embodiments, one or more members (that may or may not include one or more springs) will be employed to maintain the roller in the channel.
It should further be appreciated that in other alternative embodiments, the walls of the channel are parallel or substantially parallel, and that one or more members (that may or may not include one or more springs) will be employed to maintain the roller in the channel.
The configuration of the warp restraint 100, and specifically the configuration of the first inner bearing race 110, the second opposing outer bearing race 140, and the roller 180 positioned in a channel formed by and between the first and second opposing bearing races 110 and 140 bias or co-act to provide biasing forces on the bolster 40 and the side frame 60 toward the normal square position to reduce, inhibit, or minimize warping.
More specifically, when warping occurs as shown in
Likewise, If the warping shown on the left end of the bolster in
It should also be appreciated that if the warping was reversed such that the left side frame 60 was ahead of the right side frame 60 in the truck 50 of the present disclosure, the warp restraints 200 and 300 would both act or co-act to apply biasing forces to the right end portion of the bolster 40 to cause the bolster 40 to return to its normal or square position and thus co-act to reduce, inhibit, or minimize warping. In other words, the opposite corner rollers 280 and 380 of the opposite corner warp restraints 200 and 300 would be compressed and would exert opposing forces.
Likewise, it should also be appreciated that if the warping was reversed such that the left side frame 80 was ahead of the right side frame 60 in the truck 50 of the present disclosure, the warp restraints 500 and 800 would both act or co-act to apply biasing forces to the left end portion of the bolster 40 to cause the bolster 40 to return to its normal or square position and thus co-act to reduce, inhibit, or minimize warping. In other words, the opposite corner rollers 580 and 880 of the opposite corner warp restraints 500 and 800 would be compressed and would exert opposing forces.
The eight warp restraints 100, 200, 300, 400, 500, 600, 700, and 800 of this illustrated example embodiment thus co-act in opposing or transverse groups to bias the bolster toward the square positions relative to the side frames 60 and 80 such that the centerline or center plane of the bolster (that extends transversely relative to straight tracks) is perpendicular or substantially perpendicular to the centerlines or center planes of the respective side frames 60 and 80 (that extend longitudinally relative to straight tracks).
In various embodiments and in various circumstances, the eight warp restraints 100, 200, 300, 400, 500, 600, 700, and 800 may also act to provide other biasing forces to the bolster relative to the side frames and/or may co-act with one or more other components of the railroad car truck to provide other biasing forces to the bolster relative to the side frames. These other biasing effects of the warp restraints of the present disclosure can be considered as secondary potential biasing effects.
More specifically, known prior art railroad cars trucks typically generally have bolsters that have free lateral or transverse movement relative to the side frames of around +/−½ inches, where the end of that lateral or transverse travel is limited by or arrested by stopping members that are often called “Gibs”. Gibs are the physical blocks that prevent movement beyond this travel allowance. These Gibs are generally shown in
In the case where the warp restraints of the present disclosure replace the Gibs, the outer walls of the bearing races can perform the function of the Gibs. In the case where the warp restraints of the present disclosure do not replace the Gibs, the warp restraints will allow for limited lateral movement of the bolster relative to the side frames. In certain embodiments, depending upon: (a) the position, shape, and angles of the bearing races; and (b) the shape, size, and elasticity of the rollers, the warp restraints may assist or help to limit the lateral movement of the bolster relative to the side frames.
In another example of possible secondary biasing forces provided by the warp restraints of the present disclosure, the warp restraints 100, 200, 300, 400, 500, 600, 700, and 800 may co-act with the springs or spring groups of the truck to provide other biasing forces to the bolster relative to the side frames. The lateral or transverse movement of the bolster relative to the side frames is partially controlled by the equilibrium preference of the spring group on which the bolster rides. In other words, the spring groups provide lateral as well as vertical elasticity to the interaction between the bolster and the springs. More specifically, in certain embodiments of the warp restraints such as the embodiments with purely cylindrical rollers such as shown in
This is generally shown in
In other embodiments of the present disclosure where the rollers are not purely cylindrical, but rather are more curved or radiused such as the alternative embodiment roller 2180 shown in
Thus, in certain circumstances and certain embodiments of the present disclosure, if the bolster 40 moves laterally or transversely outwardly relative to the side frame 60, the warp restraints may be expected to exert certain biasing forces on those respective bearing races that will in turn transfer such forces to the bolster 40 and the side frame 60 to cause the bolster 40 to move in an opposite direction laterally or transversely inwardly relative to the side frame 60 and return to its normal position. Likewise, in certain circumstances and embodiments of the present disclosure, if the bolster 40 moves laterally or transversely inwardly relative to the side frame 60, the warp restraints may be expected to exert certain biasing forces on those respective bearing races that will in turn transfer such forces to the bolster 40 and the side frame 60 to cause the bolster 40 to move in an opposite direction laterally or transversely outwardly relative to the side frame 60 and return to its normal position.
The warp restraints of certain embodiments of the present disclosure can also reduce, inhibit, or minimize longitudinally movement of the bolsters relative to the side frames depending upon: (a) the shape and angles of the bearing races; and (b) the shape, size, and elasticity of the rollers. For example, if the bolster 40 begins to move forward longitudinally relative to the side frame 60, the roller 180 between the bearing races 110 and 140 will be squeezed and may be expected to exert biasing forces on those respective bearing races 110 and 140, that will in turn transfer such forces to the bolster 40 and the side frame 60 to cause the bolster 40 to move in an opposite direction rearwardly longitudinally relative to the side frame 60 and return to its normal position. Likewise, if the bolster 40 begins to move rearward longitudinally relative to the side frame 60, the roller 280 between the bearing races 210 and 240 will be squeezed and may be expected to exert biasing forces on those respective bearing races 210 and 240 that will in turn transfer such forces to the bolster 40 and the side frame 60 to cause the bolster 40 to move in an opposite direction forwardly longitudinally relative to the side frame 60 and return to its normal position.
It should also be appreciated that most movements of the bolster 40 relative to the side frames 60 and 80 will likely be in a direction that may be a combination of different directions. In such cases, the warp restraints 100, 200, 300, 400, 500, 600, 700, and 800 can act in combination or co-act with one or more other components of the truck to cause the bolster 40 and side frames 60 and 80 to move in opposing directions to return to their normal positions thus co-act to reduce, inhibit, or minimize warping while also possibly applying other additional secondary forces as explained above.
Additionally, it should be appreciated that the warp restraints of the present disclosure can be employed to take up clearance between the side frame and bolster, thereby producing more resistance to truck warping.
In various embodiments, the rollers are made of a suitable material with lower hardness than the truck castings (e.g., the side frame and bolster castings), and such that the rollers are somewhat sacrificial. It is expected that these sacrificial rollers will need to be replaced periodically once substantial wear of the roller has reduced the effectiveness of that roller.
In the illustrated embodiment of
Thus, it should be appreciated that the roller employed in certain preferred embodiments of the present disclosure will likely be generally cylindrical with rounded or radiused edges such as the roller 2180 shown in
As mentioned above, it should be appreciated that the rollers of the warp restraints may be differently formed and in particular the rollers may not be cylindrical (as shown in
In other example embodiments of the present disclosure, the roller is in the form of a spherical ball. In the spherical ball alternative shape, the roller facilitates vertical motion of the bolster relative to the side frame by rolling about the central laterally extending axis of the roller. This alternative roller also provides a certain amount of resistance or bias against lateral movement since it can roll perpendicular to its central laterally extending axis. In certain instances, this would be functionally less ideal since the Gib function at the end of the lateral travel would be reduced to point contacts.
In other alternative example embodiments of the present disclosure, the rollers are trapezoidal shaped or triangular, wherein the tapered or narrower end is positioned toward the bottom sections of the bearing races and the wider end is positioned toward the top sections of the bearing races. In such embodiments, the rollers can be made from a relatively hard plastic material with self-lubricating characteristics such as from a DELRIN material.
It should further be appreciated that over the expected life of each roller or as each roller wears, it is expected that the diameter of the roller will decrease due to: (1) abrasion against the surfaces upon which the roller rolls (i.e., the surfaces of the bearing races); (2) plastic deformation of the roller due to compression; (3) corrosion; and/or (4) other degenerative processes. In the case of vertical, finite, reciprocal motion, this reduction in roller diameter is accounted for by aligning the bearing race surfaces at slight inward angles relative to the direction of displacement. Thus, as the roller diameter becomes smaller, the roller proceeds along the line of action as the distance between the contact points between each bearing race and the roller surface tend to become nearer. In other words, as the roller becomes smaller, its axis of rotation relative to the bearing race will be relatively lower or closer to the tracks or rails, and thus provide substantially the same relative forces on the bearing races. In such cases, the worn roller (such as the roller shown in
It should also be appreciated that as the roller wears down, the rounded, radius, or curved outer bearing race engagement surface of the roller (such as the roller in
It should further be appreciated that the warp restraints of the present disclosure require relatively little material to provide additional stiffness.
It should be appreciated that in various embodiments, one or more of the surfaces of the bearing race do not need any lubrication.
It should be appreciated that in various embodiments, one or more of the surfaces of the bearing race are self-lubricating.
Referring now to the
In this illustrated embodiment, the torsion bar 1900 includes a tubular body 1910 and two spaced apart arms 1920 and 1940. One end of arm 1920 is connected to the tubular body 1910 and the opposite end is connected to roller 1180. Likewise, one end of arm 1940 is connected to the tubular body 1910 and the opposite end is connected to roller 1280. It should be appreciated that any suitable connectors may be employed in accordance with the present disclosure. The torsion bar 1900 is configured to assist in automatically returning the roller 1180 and 1280 to equal vertical alignment that in turn assists in forcing the bolster back to the center or central position.
In this alternative embodiment, to further reduce, inhibit, or minimize warping, pairs of rollers are employed. Each individual roller of a roller pair is allowed to move vertically in an independent manner, and under certain circumstances is forced to be re-aligned with one another. The torsion bar is provided to enable ongoing independent movement as needed, while also assuring that both rollers return to their nominal relative alignment.
If the railroad car truck with the warp restraints manages (against considerable resistance from the rollers) to become displaced into a warped condition where the rollers actually tend to retain the truck in that warped configuration, the torsion bars will function to cause the rollers to return to their desired positions.
Referring now to
Like the above embodiment, in this illustrated example embodiment of the present disclosure, the railroad car truck with warp restraints 5050 includes: (1) a first plurality or set of warp restraints (which are only partially shown); and (2) a second plurality or set of warp restraints (which are only partially shown). Only warp restraints 5200 and 5400 are discussed herein as examples of the inner and outer warp restraints of this alternative example embodiment of the present disclosure.
More specifically, in this illustrated embodiment, (a) example warp restraint 5200 includes a first inner bearing race 5210 integrally formed at and extending from the first end portion of the bolster 5040, a second opposing outer bearing race 5240 integrally formed at and extending from the first side frame 5060, and a roller 5280 positioned in a channel formed by and between the first and second opposing bearing races 5210 and 5240; and (b) warp restraint 5400 includes a first inner bearing race 5410 integrally formed at and extending from the first end portion of the bolster 5040, a second opposing outer bearing race 5440 integrally formed at and extending from the first side frame 5060, and a roller 5480 positioned in a channel formed by and between the first and second opposing bearing races 5410 and 5440. Thus, other warp restraints of this alternative example embodiment are similarly formed as these warp restraints.
In this illustrated example embodiment, the first inner bearing race 5210 of warp restraint 5200 is connected to the first end portion of the bolster 5040 by generally or substantially vertically extending race bearing side connectors 5212 and 5214 that are each integrally connected by welding to the bolster 5040 and to opposite outer surfaces of the opposing side walls of the bearing race 5210.
In this illustrated example embodiment (as best shown in
In this illustrated example embodiment (as best shown in
In this illustrated example embodiment, the second outer bearing race 5440 of warp restraint 5400 is connected to the first side frame 5060 by a generally or substantially vertically extending race bearing side connector 5448 integrally connected by welding to the side frame 5060 and to outer surface of the outer side wall of the bearing race 5440. In this illustrated example embodiment, the second outer bearing race 5440 of warp restraint 5400 is also connected to the first side frame 5060 by the two spaced apart generally or substantially horizontally extending race bearing side connectors 5242 and 5244 integrally connected by welding to the side frame 5060 and to outer surface of the center wall of the bearing race 5440. In this illustrated example embodiment, an additional angled race bearing side connector 5442 is integrally connected by welding to the side frame 5060 and to the race bearing side connectors 5242 and 5244.
It should be appreciated from above and from the example embodiment of
It should also be appreciated from above that in various alternative embodiments of the present disclosure, the angles of the channels and the outer diameters of the respective rollers may vary.
It should also be appreciated that in various alternative embodiments of the present disclosure, one or more attachment mechanisms such as one or more hooks (not shown) can be attached to the roller to maintain the roller between the two opposing bearing races.
It should further be appreciated that in various alternative embodiments of the present disclosure, one or more of the rollers are trapezoidal shaped (not shown) or are in a trapezoidal shape form (not shown) that is positioned between the two opposing bearing races. In certain such embodiments, the trapezoidal member has a smaller width at its bottom portion and tapers to a larger width at its top portion, The taper is continuous in various embodiments and non-continuous in other embodiments. In certain such non-continuous embodiments, the taper is stepped.
It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention, and it is understood that this application is to be limited only by the scope of the claims.
This application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 62/270,331, filed Dec. 21, 2015, entitled RAILROAD CAR TRUCK WITH WARP RESTRAINTS, the entire contents of which are incorporated herein by reference.
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20170174232 A1 | Jun 2017 | US |
Number | Date | Country | |
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62270331 | Dec 2015 | US |