Patent Application
20220194495
The present disclosure relates to an idler used to guide a track chain assembly of an endless undercarriage drive employed by earth moving, construction and mining equipment and the like. Specifically, the present disclosure relates to such an idler that is assembled using idler segments that may decrease the likelihood of scalloping developing on the links of the track chain assembly.
Earth moving, construction and mining equipment and the like are often used in rough, off-road terrain. These machines often employ an endless drive with track shoes that is better able to propel the machines in such environments over obstacles and uneven terrain, etc. The track chain assemblies, which include shoes, are held together by a series of interconnected track links, pins and bushings that are supported on the drive sprocket, idler and support rollers of the machine. The drive sprocket, is so called, as it may drive or convey power to the track chain assembly, causing it to revolve about the idler wheels, resulting in linear motion of the machine. The idler wheels provide guidance to the track chain assembly, helping to keep the track chain assembly on the undercarriage.
Heavy loads are often exerted on the idler, which is typically round, that contacts the flat surfaces of the links of the track chain assembly. Over time, scalloping may occur on the links of the track chain assembly at the interface between the round idler and the links. This scalloping may cause an uneven ride and eventually results in unwanted maintenance and downtime for the machine.
For example, the links and/or track chain assembly as a whole may need to be replaced or repaired.
An idler assembly according to an embodiment of the present disclosure may comprise a cylindrical hub defining an axis of rotation, a radial direction, and a circumferential direction, and may include a stepped circumferential surface having a first radially inner face, and a radially outer cylindrical face. A plurality of mounting holes may extend radially into the radially outer cylindrical face. The idler assembly may also have a first idler segment including an at least partially flat body having a first planar chain link contacting surface. The cylindrical hub may have a first set of metallurgical properties that is different than the second set of metallurgical properties of the first idler segment.
An idler segment according to an embodiment of the present disclosure may comprise an at least partial flat body including defining a longitudinal direction, a lateral direction that is perpendicular to the longitudinal direction, and a vertical direction that is perpendicular to the lateral direction and the vertical direction. The body may further define a first longitudinal end, a second longitudinal end, a first lateral end, a second lateral end, a first vertical extremity, and a second vertical extremity. A first flat rail surface may extend laterally from the first lateral end toward the second lateral end, while a second flat rail surface may extend laterally from the second lateral end toward the first lateral end. A guide ridge may laterally connect the first flat rail surface to the second flat rail surface.
An idler segment according to another embodiment of the present disclosure may comprise an at least a partial body of revolution including defining a circumferential direction, a radial direction, and an axis of rotation. A guide ridge may extend axially, radially, and circumferentially, while a first planar contact surface may extend axially from the guide ridge on one side and a second planar contact surface may extending axially from the guide ridge on the other side. The first planar contact surface may comprise a first material zone with a first property, and a remaining portion of the at least partial body of revolution comprises a second material zone with a second property that is different than the first property.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure. In the drawings:
Reference will now be made in detail to embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. In some cases, a reference number will be indicated in this specification and the drawings will show the reference number followed by a letter for example, 100a, 100b or by a prime for example, 100′, 100″ etc. It is to be understood that the use of letters or primes immediately after a reference number indicates that these features are similarly shaped and have similar function as is often the case when geometry is mirrored about a plane of symmetry. For ease of explanation in this specification, letters and primes will often not be included herein but may be shown in the drawings to indicate duplications of features, having similar or identical function or geometry, discussed within this written specification.
An undercarriage assembly that may use an idler assembly or an idler segment according to various embodiments of the present disclosure will now be described.
While the arrangement is illustrated in connection with a bull dozer, the arrangement disclosed herein has universal applicability in various other types of machines commonly employ track systems, as opposed to wheels. The term “machine” may refer to any machine that performs some type of operation associated with an industry such as mining, earth moving or construction, or any other industry known in the art. For example, the machine may be an excavator, a wheel loader, a cable shovel, a track type tractor, a hydraulic mining shovel, or dragline or the like. Moreover, one or more implements may be connected to the machine. Such implements may be utilized for a variety of tasks, including, for example, lifting and loading.
As shown in
Its undercarriage structure includes a supporting structure that supports the track system 102 utilized for movement of the machine 100. The track system 102 may include first and second track roller frame assemblies 116, which are spaced from and adjacent respective first and second sides of the undercarriage assembly. It will be appreciated that only one of the track roller frame assemblies 116 is visible in
Each of the track roller frame assemblies 116 carries a front idler wheel 120, a drive sprocket assembly 122, and a plurality of track guiding rollers 124. The drive sprocket assembly 122, is powered in forward and reverse directions by the machine 100. An endless track chain assembly 126 encircles each drive sprocket assembly 122, the front idler wheel 128, rear idler wheel assembly (e.g., see 200) and the track guiding rollers 124. The track chain assembly 126 includes a plurality of interconnected track links 110 and track shoes 112. The track guiding rollers 124 and idlers 120, 200 guide the track links 110 as the track chain assembly 126 is driven by the drive sprocket wheel assembly 122. The track chain assembly 126 may have any track chain member, track pin retention device, and/or track chain assembly. A power source 130 supplies the power to drive the track chain assembly 126 via the sprocket assembly 122, as the lugs of the drive sprocket assembly 122 engage the various track bushings (not shown in
Power source 130 may drive the sprocket assembly 122 of machine 100 at a range of output speeds and torques. Power source 130 may be an engine such as, for example, a diesel engine, a gasoline engine, a gaseous fuel-powered engine, or any other suitable engine. Power source 130 may also be a non-combustion source of power such as, for example, a fuel cell, a power storage device, or any other source of power known or that will be devised in the art.
Turning now to
An idler assembly 200 may comprise a cylindrical hub 202 defining an axis of rotation 204, a radial direction 206, and a circumferential direction 208. As best seen in
The cylindrical hub 202 may have a first set of metallurgical properties that is different than a second set of metallurgical properties of the first idler segment.
More particularly, there may be a difference between the first set of metallurgical properties of the cylindrical hub 202, and the second set of metallurgical properties of the first idler segment 300 that includes at least one of the following: a material composition, a hardness, a coating, or a distribution of the material composition, the hardness, or the coating.
In some embodiments of the present disclosure, the first idler segment 300 has a different material composition than the cylindrical hub 202. For example, the first idler segment 300 may be made from steel while the cylindrical hub 202 may be made from iron, grey-cast iron, etc. Or, the first idler segment may be at least partially hardened to a higher hardness than the cylindrical hub. Or, a coating may be applied to the first planar chain link contacting surface to increase hardness and/or reduce wear. This coating may be omitted from the cylindrical hub. Any combination of these differences may be employed, etc.
Focusing on the geometry shown in
As best seen in
Looking at
Similarly, the stepped circumferential surface 210 of the cylindrical hub 202 may include a second radially inner face 212a (see
As can be best understood by looking at
Next, an idler segment that may be used to assemble the idler assembly 200 as just described herein, or as a replacement part will now be described with reference to
Starting with
A first flat rail surface (e.g., see 302) may extend laterally from the first lateral end 326 toward the second lateral end 328, while a second flat rail surface (e.g., see 302a) extending laterally from the second lateral end 328 toward the first lateral end 326. A guide ridge (e.g., see 306) may extend laterally connecting the first flat rail surface to the second flat rail surface.
This guide ridge may include a convex arcuate surface (e.g., see 312) that defines the first vertical extremity 330. In some embodiments, a first concave arcuate surface 334 may be disposed vertically below the first flat rail surface (e.g., see 302), and that defines the second vertical extremity 332. Alternatively, a first parallel flat surface 344 (see
In like fashion, a second concave arcuate surface may be disposed vertically below the second flat rail surface (e.g., see 302a) and that is coextensive with the first concave arcuate surface. That is to say, they would form the same cylindrical surface if not interrupted by the guiding ridge. Alternatively, another parallel flat surface 344a (see
In
Another idler segment 300 constructed according to another embodiment of the present disclosure for use with the idler assembly 200 may be characterized as follows.
Looking at
A guide ridge (e.g., see 306) may extend axially, radially, and circumferentially to the circumferential extremities (e.g., see 322 and 324) of the idler segment 300. A first planar contact surface (e.g., see 302) may extend axially from the guide ridge to an axial extremity (e.g., see 326) of the idler segment (300), and a second planar contact surface (e.g., see 302a) may extend axially from the guide ridge to the opposite axial extremity (e.g., see 328).
In certain embodiments of the present disclosure, the first planar contact surface (e.g., see 302) comprises a first material zone 336 (see
For example, the first property may be a first material, and the second property may be a second material that is different than the first. Or, the first property is a coating, and the second property is a lack of coating. Or, the first property is a first material hardness, and the second property is a second material hardness that is different than the first material hardness, etc.
Focusing on
In
The first planar contact surface, the first radially extending surface, the radially outer circumferential surface, the second radially extending surface, and the second planar contact surface may share the same first material zone 336 that extends axially, and circumferentially to include an entirety of the first planar contact surface, the first radially extending surface, the radially outer circumferential surface, the second radially extending surface, and the second planar contact surface in some embodiments of the present disclosure.
Any of the aforementioned features may be differently configured or dimensioned than what has been specifically described herein in various embodiments of the present disclosure.
For many embodiments, the idler segment and/or hub may be cast using iron, grey-iron, steel or other suitable materials. Other manufacturing processes may be used such as any type of machining, forging, etc. For example, steel or “tough steel” may be used to create the idler segments. Idler segments may also be coated, heat treated, etc. to provide suitable characteristics for various applications.
In practice, an idler assembly, an idler segment, and an undercarriage assembly according to any embodiment described herein may be sold, bought, manufactured or otherwise obtained in an OEM (original equipment manufacturer) or after-market context.
The various embodiments of the idler segments may help to share the loads between adjacent segments, reducing the load borne by any single segment or its fasteners, etc. Also, the width of the idler segments may be varied to provide versatility to accommodate different track chain assemblies.
As used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.” Where only one item is intended, the term “one” or similar language is used. Also, as used herein, the terms “has”, “have”, “having”, “with” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.
It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the apparatus and methods of assembly as discussed herein without departing from the scope or spirit of the invention(s). Other embodiments of this disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the various embodiments disclosed herein. For example, some of the equipment may be constructed and function differently than what has been described herein and certain steps of any method may be omitted, performed in an order that is different than what has been specifically mentioned or in some cases performed simultaneously or in sub-steps. Furthermore, variations or modifications to certain aspects or features of various embodiments may be made to create further embodiments and features and aspects of various embodiments may be added to or substituted for other features or aspects of other embodiments in order to provide still further embodiments.
Accordingly, it is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention(s) being indicated by the following claims and their equivalents.
