Patent Application
20170014940
The present disclosure relates generally to track shoes for an endless track of a tracked undercarriage and, more particularly, to methods of fabricating a track shoe using friction welding.
Many track-type machines have tracked undercarriages that move along the ground as the machine travels. Examples of track-type machines with tracked undercarriages may include, but are not limited to, excavators, tractors, dozers, and the like. Generally, tracked undercarriages include an endless or continuous track driven around two or more wheels. An endless track can better distribute the force the track-type machine applies to the ground as a result of the large surface area of the track as compared to the wheels alone. This may allow a track-type machine with an endless track to traverse soft ground with lower likelihood of becoming stuck, for example, due to sinking In addition to distributing the force the track-type machine applies to the ground over a wider area, endless tracks may also increase traction and durability of the machine.
The endless track of a tracked undercarriage is often made of modular plates called track shoes. Track shoes are typically made from special rolled sections of steel that require expensive tooling to manufacture. A track shoe may include a grouser, which is a component that protrudes from a surface of the track shoe that increases the traction of the endless track. It is particularly challenging to manufacture a track shoe with a grouser, especially for larger track-type machines.
A method of replacing a wear bar on a crawler using friction welding is disclosed in U.S. Patent Application Publication No. 2008/0309157. However, the method does not alleviate the problem of fabricating a fully formed track shoe with a grouser using friction welding.
In one aspect, the present disclosure describes a method of fabricating a track shoe that comprises friction welding a grouser to a track shoe blank. In another aspect, the present disclosure describes a method of fabricating a track shoe that comprises friction welding a first track shoe portion that includes a grouser to a second track shoe portion. In yet another aspect, the present disclosure describes a track shoe that comprises a track shoe blank and a grouser that protrudes from a flat portion of the track shoe blank and that is fused to the track shoe blank by friction welding. In still another aspect, the present disclosure describes a track shoe that comprises a first track shoe portion that includes a grouser and a second track shoe portion fused to the first track shoe portion by friction welding.
The present disclosure relates to a track shoe and methods of fabricating a track shoe using friction welding.
The undercarriage system 2 supports machine 1 and moves machine 1 along the ground, roads, and other types of terrain. As shown in
Endless track 4 may include a link assembly 11 with a plurality of track shoes 12 secured thereto. Each track shoe 12 on link assembly 11 is adjacent to and in engagement with another track shoe 12 on either side thereof, forming endless track 4. The link assembly 11 forms a flexible backbone of endless track 4, and the track shoes 12 provide traction on the surface on which machine 1 is located, Link assembly 11 extends in an endless track 4 around drive sprocket 6, rollers 8, idler 7, and carriers 10. More specifically, link assembly 11 includes a plurality of links 13 connected to one another at pivot joints 14, with each link 13 including a track shoe 12 attached thereto. Undercarriage system 2 could have other configurations.
A track shoe 12 according to the present disclosure is shown in FIG, 3. Track shoe 12 includes a grouser 15 protruding from flat portion 16. As machine 1 travels on a surface, grouser 15 conies into contact with the surface, increasing the traction of endless track 4. In the embodiment shown, grouser 15 protrudes generally orthogonally from flat portion 16, yet grouser 15 may protrude at other angles with respect to flat portion 16, including acute and obtuse angles. Although grouser 15 is shown as having a generally quadrilateral-type profile, grouser 15 may have a different profile, including a generally triangular profile or a claw-type profile. Track shoe 12 may also have more than one grouser 15 attached thereto.
Track shoe 12 includes a leading edge 17 and a trailing edge 18. Leading edge 17 is tapered and angled with respect to fiat portion 16 of track shoe blank 19 in a direction generally opposite from the direction in which grouser 15 protrudes from track shoe blank 19. Trailing edge 18 is tapered and angled with respect to flat portion 16 of track shoe blank 19 in generally the same direction in which grouser 15 protrudes from track shoe blank 19. In this manner, when a plurality of track shoes 12 are joined together to form endless track 4 on track assembly 3, the leading edge 17 of a first track shoe 12 is proximal to a trailing edge 18 of an adjacent track shoe 12.
Another variation of track shoe 12 according to the present disclosure is shown in
In one embodiment, track shoe 12 is formed from track shoe blank 19.
As shown in
In order to linearly friction weld grouser 15 to track shoe blank 19, track shoe blank 19 is held stationary, for example in a press or a chuck. Grouser 15 is brought within close proximity of a target fusing location 20 on track shoe blank 19 where grouser 15 is to be attached. In the embodiment shown, target fusing location 20 is disposed on flat portion 16 of track shoe blank 19. Target fusing location 20 may be in other locations on track shoe blank 19. When grouser 15 is in close proximity of target fusing location 20, a second abutment surface 22 on grouser 15 contacts a first abutment surface 21 of track shoe blank 19 at an abutment surface interface 25. Grouser 15 is then vibrated back and forth in a direction of vibration 23 that is generally parallel to flat portion 16 of track shoe blank 19 and orthogonal to an upset force 24 that acts on grouser 15 to push second abutment surface 22 into first abutment surface 21 at target fusing location 20. The vibration of grouser 15 in the direction of vibration 23 results in an overall range of movement of grouser 15 in the direction of vibration 23 of a few millimeters. As a result of the upset force 24 pushing second abutment surface 22 of grouser 15 into first abutment surface 21 of track shoe blank 19 and the vibration of grouser 15 with respect to track shoe blank 19, second abutment surface 22 of grouser 15 fuses with first abutment surface 21 of track shoe blank 19 at abutment surface interface 25, creating a track shoe 12 comprising track shoe blank 19 with grouser 15 attached thereto. The linearly friction welded track shoe 12 is shown in
Although
Another embodiment of a method of fabricating a track shoe using linear friction welding is shown in
In order to linear friction weld first track shoe portion 26 to second track shoe portion 27, first track shoe portion 26 is held stationary. Second track shoe portion 27 is brought within close proximity of a target fusing location 20 on first track shoe portion 26 where second track shoe portion 27 is to be attached. In the embodiment shown, target fusing location 20 is disposed adjacent to grouser 15 of first track shoe portion 26. Target fusing location 20 may be in other locations on first track shoe portion 26, When second track shoe portion 27 is in close proximity of target fusing location 20, a second abutment surface 22 on second track shoe portion 27 contacts a first abutment surface 21 of first track shoe portion 26 at an abutment surface 25. Second track shoe portion 27 is then vibrated back and forth in a direction of vibration 23 that is generally parallel to first abutment surface 21 and generally orthogonal to an upset force 24 that acts on second track shoe portion 27 to push second abutment surface 22 into first abutment surface 21. The vibration of second track shoe portion 27 in the direction of vibration 23 results in an overall range of movement of second track shoe portion 27 in the direction of vibration 23 of a few millimeters. As a result of the upset force 24 pushing second abutment surface 22 of second track shoe portion 27 into first abutment surface 21 of first track shoe portion 26 and the vibration of second track shoe portion 27 with respect to first track shoe portion 26, second abutment surface 22 of second track shoe portion 27 fuses with first abutment surface 21 of first track shoe portion 26 at abutment surface interface 25, creating a track shoe 12 comprising first track shoe portion 26 and second track shoe portion 27. The linearly friction welded track shoe 12 is shown in
Yet another embodiment of a method of fabricating a track shoe using linear friction welding is shown in
In another embodiment, track shoe blank 19 may be a second track shoe portion 27 and grouser 15 may be disposed on a first track shoe portion 26. First track shoe portion 26 may be friction welded to second track shoe portion 27 to fabricate a track shoe 12 comprising the first track shoe portion 26 with grouser 15 and the second track shoe portion 27.
Although
In linear friction welding, typically the more massive component of the two components to be fused to together (that is track shoe blank 19 rather than grouser 15 and first track shoe portion 26 rather than second track shoe portion 27) is held stationary while the less massive component is vibrated and subjected to an upset force. It is also contemplated, however, that the less massive component (i.e., grouser 15 rather than track shoe blank 19 and second track shoe portion 27 rather than first track shoe portion 26) can be held stationary while the more massive component is vibrated and subjected to an upset force.
Orbital friction welding is another friction welding technique contemplated in the present disclosure. In orbital friction welding, a first abutment surface of a first component is brought within close proximity of a second abutment surface of a second component such that the first abutment surface contacts the second abutment surface at an abutment surface interface. Initially, the first component is displaced from the second component along the plane of the abutment surface interface by a small distance, or offset, such that the first abutment surface is not aligned, or is not congruent, with the second abutment surface. The offset is typically one or a few millimeters. The first component is then rotated with respect to the second component, or, alternatively, the second component is rotated with respect to the first component, along a small circular or elliptical path, or orbit, while both the first component and the second component are subjected to equal and opposite upset forces that push the first abutment surface into the second abutment surface, creating welding heat at the abutment surface interface. As the rotation along the orbit continues, the magnitude of each upset force is held constant or increased and the offset is continually decreased until it becomes zero, at which point the first abutment surface becomes aligned, or congruent, with the second abutment surface. The first abutment surface of the first component is then fused to the second abutment surface of the second component at the abutment surface interface, creating a single piece comprising the first component orbitally friction welded to the second component. Excess flash or waste material produced near the abutment surface interface can be removed, for example with a laser.
In order to orbitally friction weld grouser 15 to track shoe blank 19, grouser 15 is brought within close proximity of track shoe blank 19 such that a first abutment surface 21 of track shoe blank 19 contacts a second abutment surface 22 of grouser 15 at an abutment surface interface 25. Initially, track shoe blank 19 is displaced from grouser 15 along a plane of abutment surface interface 25 by offset O, such that first abutment surface 21 is not aligned, or is not congruent, with second abutment surface 22. Grouser 15 is then rotated with respect to track shoe blank 19 or, alternatively, track shoe blank 19 is rotated with respect to grouser 15, along orbit 28 in direction of rotation 29, while both track shoe blank 19 and grouser 15 are subjected to equal and opposite upset forces 24 that push first abutment surface 21 into second abutment surface 22, creating welding heat at the abutment surface interface 25. As the rotation along orbit 28 continues, the magnitude of each upset force 24 is held constant or increased and offset O is continually decreased until it becomes zero, at which point first abutment surface 21 becomes aligned, or congruent, with second abutment surface 22. First abutment surface 21 of track shoe blank 19 is then fused to second abutment surface 22 of grouser 15 at abutment surface interface 25, creating a track shoe 12 comprising the grouser 15 orbitally friction welded to the track shoe blank 19.
Although
The method shown in
Referring again to
Although
First track shoe portion 26 and second track shoe portion 27 may be of a standardized form, meaning that a large number of first track shoe portions 26 and second track shoe portions 27 can be readily obtained in large quantities from any number of suppliers and/or that first track shoe portion 26 and second track shoe portion 27 do not require significant manufacturing expense to produce. For example, first track shoe portion 26 shown in
While first track shoe portion 26 and second track shoe portion 27 of
In orbital friction welding, typically the more massive component of the two components to be fused together (i.e., track shoe blank 19 rather than grouser 15 and first track shoe portion 26 rather than second track shoe portion 27) is held stationary while the less massive component is rotated with respect to the more massive component. It is also contemplated, however, that the less massive component (i.e., grouser 15 rather than track shoe blank 19 and second track shoe portion 27 rather than first track shoe portion 26) can be held stationary while the more massive component is rotated with respect to the less massive component.
It is also contemplated that one or more of track shoe blank 19, grouser 15, first track shoe portion 26, and second track shoe portion 27 may be comprised of two or more components that have already been friction welded together, whether by linear friction welding or orbital friction welding. For example, referring to
It is further contemplated that first abutment surface 21 and second abutment surface 22 may each be comprised of a number of discrete surfaces. For example, while
In general, the methods and track shoes of the present disclosure are applicable for use in various industrial applications, such as earthmoving, construction, landscaping, forestry, and agricultural machines. In particular, the disclosed methods and resulting track shoes may be used on any machine with an endless track on the tracked undercarriage, such as earth-moving vehicles, excavators, tractors, dozers, loaders, backhoes, agricultural equipment, material handling equipment, and the like.
Fabricating a track shoe according to the methods of the present disclosure may provide a less costly and more efficient alternative to current fabrication techniques, which require expensive tooling and extrusion procedures. More specifically, current fabrication techniques typically require extruding a lengthy rectangular beam of steel into a desired track shoe shape, cutting the extruded piece material into appropriately sized sections, punching a hole in each section where a grouser is to be attached, and attaching the grouser to the cut section. Fabricating a track shoe according to the methods of the present disclosure, in contrast, may allow for the fabrication of a track shoe using friction welding, which may reduce fabrication complexity and result in lower fabrication costs. The disclosed methods may also limit the need for the expensive tooling and extrusion procedures of current fabrication techniques. In particular, the methods of the present disclosure may be used to fabricate a smaller number of track shoes, to fabricate track shoes for legacy machines for which replacement parts may be difficult to find, and to fabricate track shoes that include grousers for larger machines.
This disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.
