Idler height adjustment for undercarriage systems using flowable material displacement

Abstract

An undercarriage system (18) for a track-type machine (10) has piston assemblies (34, 38) supported on a frame (12) on opposite sides thereof and includes an idler height adjustment system (32) in contact with upper and lower sides (75, 77) of an idler support element (44) or block. A conduit (46) connects the piston assemblies (34, 38) and has a fluid exchange valve (48) therein that is adjustable between an open position in which a flowable material, such as grease, is exchanged between the piston assemblies (34, 38) through the conduit (46), and a closed position in which fluid communication between the piston assemblies (34, 38) is blocked and the idler height is fixed.

Description

[Technical Field]

[0001] The present disclosure relates generally to adjusting idler height in an undercarriage system of a track-type machine, and more specifically to an idler height adjustment system in which a conduit fluidly connects an adjustable piston assembly to set the idler height by exchanging a flowable material. [Background technology]

[0002] Tracked machines are used in many applications worldwide, including construction, forestry, landfills, mining, demolition, and a variety of other environments. In a typical design, an endless loop of coupled track links is located on each side of the machine and extends around multiple rotatable track-engaging elements. Tracked machines, particularly the undercarriage systems containing the tracks, can be subjected to extremely harsh conditions. Side loads, bending loads on components, torsional loads, impacts, and various other phenomena can lead to track distortion, wear, and performance degradation. Worksite materials, including hard rock material, sand, clay, landfill debris, and various other materials, can find their way between the components in the track. The movement of components in an undercarriage system against each other tends to wear the materials from which the undercarriage components are made, and that wear can be accelerated or exacerbated by the worksite materials. As a result, machine tracks and associated components are often constructed with a specific service life in mind, utilizing anticipated wear patterns and rates in the basic design of the components.

[0003] Nevertheless, it is typically necessary to repair undercarriage systems, tighten or otherwise adjust tracks, inspect and replace seals, and perform other basic maintenance over the course of a machine's field life. One phenomenon that can require machine downtime relates to addressing changes in idler height in response to wear on undercarriage system components. Idlers are rotatable, track-engaging elements that passively rotate and guide the tracks driven by the drive sprocket. As material wears off the idlers, tracks, and potentially other components, the idler's position relative to the other components can change. If the idler height is too high, the track advancing around the idler may contact the underlying substrate at a location behind the desired location, while if the idler height is too low, the track may contact the substrate at a location ahead of the desired location. Either scenario can adversely affect the machine's ride quality and performance.

[0004] Various techniques have been proposed over the years to allow for idler height adjustment. Shim packs or the like are provided and sometimes transported on the machine, with individual shims movable from a position above the idler to a position below the idler as the idler height gradually decreases over time due to wear on the undercarriage components. Yet another technique involves an idler support block with an off-center hole for the idler shaft. As the idler height changes, the support block can be repositioned to support the idler shaft at a different height. These and other idler height adjustment strategies are labor-intensive, require the destruction of the track, and can result in machine downtime. One known idler height adjustment strategy is described in U.S. Patent No. 7,237,631 to Livesay et al. Summary of the Invention

[0005] In one aspect, an idler height adjustment system for an idler in an undercarriage system of a track-type machine includes: a first piston assembly having a first piston movable between a forward position and a reverse position; a second piston assembly including a second piston movable between a forward position and a reverse position; and a frame supporting the first and second piston assemblies in opposite directions to one another for positioning above and below, respectively, an idler support element in the undercarriage system. The system further includes a conduit connecting the first piston assembly to the second piston assembly, and a fluid exchange valve in the conduit, the fluid exchange valve adjustable from a closed position to an open position for exchanging flowable material through the conduit between the first piston assembly and the second piston assembly.

[0006] In another aspect, an undercarriage system for a track-type machine includes an idler yoke and an idler support element coupled to the idler yoke. The system further includes a first piston assembly and a second piston assembly supported opposite each other in upper and lower positions relative to the idler support element. The system also includes a conduit connecting the first piston assembly to the second piston assembly and a fluid exchange valve in the conduit, the fluid exchange valve being adjustable from a closed position to an open position to fluidly connect the first piston assembly and the second piston assembly.

[0007] In yet another aspect, a method for adjusting an idler height in an undercarriage system of a track-type machine includes opening a fluid exchange valve in a conduit extending between a first piston assembly supported on an upper side of an idler support element in the undercarriage system and a second piston assembly supported on a lower side of the idler support element. The method further includes repositioning the idler support element relative to a track roller frame in the undercarriage system while the fluid exchange valve is open, and co-displacing the positions of the pistons in the first piston assembly and the second piston assembly based on the repositioning of the idler support element. The method further includes displacing a flowable material through the conduit based on the co-displacement of the piston positions, and closing the fluid exchange valve to set the idler height after the displacement of the flowable material. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 illustrates a partially opened view of a track-type machine having an undercarriage system, according to one embodiment. [Figure 2] FIG. 1 illustrates a perspective view of an idler height adjustment system according to one embodiment. [Figure 3] FIG. 1 is a partial cross-sectional side view of an undercarriage system having an idler located at a first elevation. [Figure 4] FIG. 4 is a partial cross-sectional side view of the undercarriage system of FIG. 3 with an idler located at a second elevation. [Figure 5] FIG. 1 is a diagram of an undercarriage system as it appears positioned for idler height adjustment according to the present disclosure.

[0009] Referring to FIG. 1 , a track-type machine according to one embodiment is shown and includes a machine frame 12 having a cab 14 mounted thereon. A mounting system 16 is supported by the frame 12, and an undercarriage system 18 is provided for machine propulsion. The machine 10 is shown in the context of a track-type tractor; however, in other embodiments, the machine 10 may include a track loader, an excavator, or even a half-track machine. The undercarriage system 18 includes a track 20 disposed on a first side of the machine 10 and typically includes an identical track on the opposite side of the machine 10. The track 20 includes an endless loop of track links coupled together with track shoes attached to the track links, and extends around a plurality of rotatable track-engaging elements, including a drive sprocket 24, an idler 30, a carrier roller 26, and a plurality of track rollers 28 structured to carry a majority of the machine 10's weight. The track 20 is shown in an oval track configuration; however, in other embodiments, the track 20 may be configured with the undercarriage system 18 in a so-called high-drive configuration. The undercarriage system 18 further includes an idler height adjustment system 32 for the idler 30 in the undercarriage system 18. The idler height adjustment system 32 (hereinafter "system 32") includes a first piston assembly 34 and a second piston assembly 38, and a conduit 46 connecting the first piston assembly 34 to the second piston assembly 38. As will become more apparent from the description below, the system 32 is uniquely configured for idler height adjustment in a fast and efficient manner without having to destroy the track 20, for example, in response to wear of components in the undercarriage system 18.

[0010] 2 and 3, the first piston assembly 34 includes a first piston 36 movable between an advanced position and a retracted position, and the second piston assembly 38 includes a second piston 40 movable between an advanced position and a retracted position. The system 32 also includes a frame 42 that supports the first piston assembly 34 and the second piston assembly 36 at upper and lower positions, respectively, relative to an idler support element 44. As configured in the system 32, the first piston assembly 34 and the second piston assembly 38 are positioned opposite each other and above and below the idler support element 44 in the undercarriage system 18. The idler support element 44 may include an idler support block. An idler yoke 50 is provided and is coupled to the idler yoke 50 in a generally conventional manner.

[0011] In the illustrated embodiment, the frame 42 includes a support frame having an upper arm 56 that contacts the first piston assembly 44, a lower arm 58 that contacts the second piston assembly 38, and a U-bend 60 connecting the upper and lower arms 56, 58. The U-bend 60 can have a generally U-shaped configuration, although various shapes that are not exactly close to a "U" can be functionally and structurally similar to the configuration shown in the drawings. The frame 42 has a plurality of bolt holes 62 formed therein that each receive a bolt for bolting the frame 42 to the track roller frame 22 in the undercarriage system 18. Additionally, the upper arm 56 forms a first receptacle 64, and the lower arm 58 forms a second receptacle 66, which receive the first and second piston assemblies 34, 38, respectively. The idler shaft 54 ​​extends within the idler support element 44, and the idler yoke 50 generally supports the idler 30 for rotation. The idler yoke 50, in some embodiments, may be coupled with an idler reaction system (not shown), such as one or more mechanical or gas springs. It will be understood that the system 32 includes substantially identical, but potentially mirror-image, components on each side of the idler 30. In particular, the first piston assembly 34 and the second piston assembly 38 may be disposed on a first side of the track roller frame 22, while the third piston assembly, the fourth piston assembly, and a second conduit connecting the third piston assembly to the fourth piston assembly may be disposed on a second side of the track roller frame 22. Descriptions and discussions herein of components on one side of the track roller frame 22 shown in the side views of FIGS. 3 and 4 should be understood to refer by analogy to components on the second side of the track roller frame 22. In some instances, the components forming system 32 on either side of track roller frame 22 may be understood as separate, independent systems. In still other embodiments, the components may be integrated into a single system or even a single assembly.

[0012] It is recalled that the conduit 46 connects the first piston assembly 34 to the second piston assembly 38. The fluid exchange valve 48 is disposed within the conduit 46 and is adjustable from a closed position to an open position to exchange flowable material through the conduit 46 between the first piston assembly 34 and the second piston assembly 38. A second conduit and second fluid exchange valve, configured in a similar manner, may be disposed on a second side of the track roller frame 32. In the illustrated embodiment, the conduit 46 extends through each of the upper and lower arms 56 and 58 to supply flowable material to and from the first and second piston assemblies 34 and 38. In FIG. 3 , the frame 42 is shown having a bore 68 formed in the upper arm 56 and another bore 70 formed in the lower arm 58. In other embodiments, the conduit 46 may extend around the sides of the frame 42 structure and otherwise fluidly connect the piston assemblies 34 and 38. The fluid exchange valve 48 is shown disposed approximately centrally in the conduit 46 between the first piston assembly 34 and the second piston assembly 38. The fluid exchange valve 48 may be disposed in other locations in other embodiments. Also, in the illustrated embodiment, the fluid exchange valve 48 includes a mechanically actuated valve having an external handle 72. The conduit 46 may be a closed conduit, meaning that the conduit 46 does not connect to, or is not connectable to, other fluid circuits in the machine 10, such as an onboard hydraulic system. Nevertheless, it is contemplated that the conduit 46, and other components of the system 32, may be part of a resident machine hydraulic system.

[0013] As described above, the conduit 46 conveys a flowable material between the first piston assembly 34 and the second piston assembly 38. The fluid exchange valve 48 has a closed position to block fluid communication between the first piston assembly 34 and the second piston assembly 38 and may be moved to an open position to fluidly connect the first piston assembly 34 and the second piston assembly 38, the significance of which will become more apparent from the following description. It should be further understood that the exchange of flowable material between the first piston assembly 34 and the second piston assembly 38 via the conduit 46 should not be interpreted as meaning that fluid within one of the piston assemblies necessarily flows to the other piston assembly when an exchange of flowable material occurs. In other words, the open fluid exchange valve 46 may be understood to fluidly connect the two sides of the system 32 such that a flowable material from one side passes to the other side, even if the material is not literally exchanged between the piston assemblies.

[0014] In a practical implementation strategy, the flowable material includes a grease-filled conduit 46. Grease contemplated herein would typically be a semi-solid or semi-fluid composition, such as one obtained by mixing oil and a thickening agent, such as soap. However, oil alone can be used; greases such as mineral oil grease or vegetable oil grease provide a practical implementation strategy. The system 32 can include a grease port 86 at a location fluidly between the first piston 36 and the second piston 40. A closure 88 blocks the grease port 86.

[0015] Referring also to FIG. 4 , note that the idler support element 44 is trapped between the first piston assembly 34 and the second piston assembly 38. The system 32 also includes a first block contact plate 74 abutting the first piston 36 and structured to contact an upper side 75 of the idler support element, and a second block contact plate 76 contacting the second piston 40 and structured to contact an underside 77 of the idler support element 44. The first block contact plate 74 and the second block contact plate 76 may each include horizontal surfaces 78 and 80 in a fixed contact pattern with a corresponding one of the first piston 36 and the second piston 40. The first block contact plate 74 and the second block contact plate 76 may each include vertical guide surfaces 82 and 84, respectively, having a sliding pattern of contact with the frame 42. FIG. 3 illustrates the idler 30 and system 18 as they might appear when the idler support element 44 and idler 30 are fully raised to substantially the maximum idler height. FIG. 4 illustrates these components as they might appear when they are fully lowered to substantially the minimum idler height. It can also be seen that the block contact plates 74 and 76 are structured to be guided while moving up and down relative to the frame 42. In particular, the first block contact plate 74 is shown as comprising legs 90 that extend generally vertically and are received in slots 92 formed in the frame 42. Pads 94 or the like may be positioned vertically between the legs 90 and the frame 42. The pads 94 may provide for cushioning, but may also have a thickness that aids in setting the idler height. Thus, different pads may be interchanged to vary the relative adjustment of the idler height that can be obtained using the system 18.

[0016] Industrial Applicability Referring generally to the drawings, and now also to FIG. 5 , it is recalled that various known idler height adjustment strategies require disruption of the track to allow for repositioning, rotation, etc. of components. The present disclosure provides a simplified adjustment system with an infinite range of idler heights that can be obtained, compared to known strategies that use shims, rotating support blocks, or other strategies. According to the present disclosure, adjusting the height of the idler 30 in the undercarriage system 18 can include opening a fluid exchange valve 48 in a conduit 46 to establish a fluid connection between the first piston assembly 34 and the second piston assembly 38. With the fluid exchange valve 48 open, the idler support element 44 can be repositioned relative to the track roller frame 22. Repositioning the idler support element 44 can displace grease through the conduit 46 between the first piston assembly 34 and the second piston assembly 38. Because system 32 is a generally closed system, moving one of pistons 36 or 40 tends to move the other of pistons 36 and 40 in response to the displacement of grease through conduit 46. The positions of pistons 36 and 40 can best be understood as co-displacement. For example, as piston 36 advances, second piston 40 retracts a similar amount due to the fluid communication of motion between first piston assembly 34 and second piston assembly 38. After displacing grease with fluid exchange valve 48 open, fluid exchange valve 48 can be closed to set the height of idler 30.

[0017] With continued reference to FIG. 5 , adjustment of the idler height can be performed by placing the machine 10 on a substantially level, typically rigid, substrate with a calibration block 110 positioned below the idler 30 and resting on the substrate. The machine 10 can be operated to drive on the calibration block 110 below the carriage system 18, particularly the track 20. With the track 20 positioned on or above the calibration block 110, the fluid exchange valve 48 can be opened to allow the idler support element 44 in the undercarriage system 18 to be lowered, or the track roller frame 22 to be lowered, under gravity, toward the calibration block 110. Also shown in FIG. 5 is a contact point 120, which can be approximately midway between the rotation axis 100 of the idler 30, which is located vertically above the calibration block 110, and the first track roller 28 in the undercarriage system 18. It is generally desirable for the grouser of the track 20 to contact the underlying substrate approximately at such point 120. If the idler height is too low, the track 20 may contact the substrate at a position forward of point 120; if the idler height is too high, the track 20 may contact the substrate at a position behind point 120. If the idler height is too high as the track 20 moves forward with the machine 10 and is positioned on the calibration support block 110, opening the fluid exchange valve 48 may allow the idler 30 and idler support element 52 to sink downward under gravity so that the track 20 rests on the calibration block 110. In such an example, if the idler height is too low, opening the fluid exchange valve 48 may allow the track roller frame 22 to sink downward under gravity, allowing the idler 30 and idler support element 44 to rise relative to the track roller frame 22. In one embodiment, the calibration block 110 may be approximately 10 millimeters thick, although the disclosure is not limited thereto.

[0018] As explained above, performance, such as grading performance and ride quality, of a track-type tractor or certain other machine can depend substantially on the relationship between idler height and roller height. This relationship changes over time due to component wear. Therefore, it will be appreciated that the present disclosure provides a system and a repeatable method that is much more easily adjusted than certain other approaches. In the illustrated embodiment, an operator or technician can operate the external handle 72 of the fluid exchange valve 48 to allow grease to flow within the conduit 46. In other examples, rather than a manual operation system, height monitoring or ride quality monitoring, or monitoring and analysis of other parameters, can be used with an electronic control system that selectively electromechanically opens and closes the fluid exchange valve, generally similar to the manual operation discussed herein.

[0019] This description is for illustrative purposes only and should not be construed to narrow the breadth of the present disclosure in any way. Accordingly, those skilled in the art will appreciate that various modifications can be made to the presently disclosed embodiments without departing from the full and fair scope and spirit of the present disclosure. Other aspects, features, and advantages will become apparent from an examination of the accompanying drawings and the appended claims. 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." When only one item is intended, the term "one" or similar language is used. Also, as used herein, the terms "has," "have," "having," and the like are intended to be open-ended terms. Furthermore, the phrase "based on" is intended to mean "based at least in part on," unless expressly stated otherwise.

Claims

1. 1. An idler height adjustment system (32) for an idler (30) in an undercarriage system (18) of a track-type machine (10), comprising: a first piston assembly (34) including a first piston (36) movable between an advanced position and a retracted position; a second piston assembly (38) including a second piston (40) movable between an advanced position and a retracted position; a frame (42) supporting the first piston assembly (34) and the second piston assembly (38) in opposite directions to each other for placement above and below, respectively, an idler support element (44) in the undercarriage system (18); a conduit (46) connecting the first piston assembly (34) to the second piston assembly (38); a fluid transfer valve (48) in the conduit (46), the fluid transfer valve (48) being adjustable from a closed position to an open position for flowing a flowable material through the conduit (46) between the first piston assembly (34) and the second piston assembly (38); the frame (42) engages the first piston assembly (34) and the second piston assembly (38); the first piston (36) of the first piston assembly (34) engages an upper portion of the idler support element (44), and the second piston (40) of the second piston assembly (38) engages a lower portion of the idler support element (44); An idler height adjustment system (32) in which, when the first piston (36) of the first piston assembly (34) advances or retreats, the second piston (40) of the second piston assembly (38) advances or retreats a similar amount, thereby moving the idler support element (44) by a similar amount due to fluid communication of motion between the first piston assembly (34) and the second piston assembly (38).

2. The frame (42) an upper arm (56) in contact with the first piston assembly (34), a lower arm (58) in contact with the second piston assembly (38), and a U-bend (60) connecting the upper arm (56) to the lower arm (58); the fluid transfer valve (48) comprises a mechanically actuated valve having an external handle (72); the conduit (46) is a closed conduit; the flowable material includes grease filling the conduit (46), and the idler height adjustment system (32) further includes a grease port (86) at a location fluidly between the first piston (36) and the second piston (40), and a closure (88) blocking the grease port (86); 2. The idler height adjustment system of claim 1, further comprising: a first block contact plate that abuts the first piston and is structured to contact an upper side of the idler support element; and a second block contact plate that contacts the second piston and is structured to contact a lower side of the idler support element.

3. the frame (42) has a plurality of bolt holes (62) formed therein for bolting the frame (42) to a track roller frame (22) of the undercarriage system (18); 3. The idler height adjustment system (32) of claim 2, wherein the upper arm (56) defines a first receptacle (64) and the lower arm (58) defines a second receptacle (66), the first receptacle (64) and the second receptacle (66) receiving the first piston assembly (34) and the second piston assembly (38), respectively.

4. 4. The idler height adjustment system (32) of claim 2 or 3, wherein the first block contact plate (74) and the second block contact plate (76) each include horizontal surfaces (78, 80) with a fixed pattern that contact the corresponding ones of the first piston (36) and the second piston (40), and vertical guide surfaces (82, 84) with a sliding pattern that contact the frame (42).

5. An undercarriage system (18) for a track-type machine (10), comprising: Idler yoke (50), an idler support element (44) coupled to the idler yoke (50); a first piston assembly (34) and a second piston assembly (38) supported opposite each other at upper and lower positions relative to said idler support element (44); a conduit (46) connecting the first piston assembly (34) to the second piston assembly (38); a fluid transfer valve (48) in the conduit (46), the fluid transfer valve (48) being adjustable from a closed position to an open position to fluidly connect the first piston assembly (34) and the second piston assembly (38); a track roller frame (22); and a frame (42) attached to the track roller frame (22) and supporting the first piston assembly (34) and the second piston assembly (38) at the upper and lower positions; the frame (42) engages the first piston assembly (34) and the second piston assembly (38); a first piston (36) of the first piston assembly (34) engages an upper portion of the idler support element (44), and a second piston (40) of the second piston assembly (38) engages a lower portion of the idler support element (44); An undercarriage system (18) in which, when the first piston (36) of the first piston assembly (34) advances or retreats, the second piston (40) of the second piston assembly (38) retreats or advances a similar amount, thereby moving the idler support element (44) due to fluid communication of motion between the first piston assembly (34) and the second piston assembly (38).

6. The undercarriage system (18) of claim 5, wherein the conduit (46) is a closed conduit and further comprises grease filling the conduit.

7. the idler support element (44) includes an idler support block trapped between the first piston assembly (34) and the second piston assembly (38); the frame (42) includes an upper arm (56) supporting the first piston assembly (34) and a lower arm (58) supporting the second piston assembly (38); the upper arm (56) forms a first receptacle (64), the lower arm (58) forms a second receptacle (66), the first receptacle (64) and the second receptacle (66) receive the first piston assembly (34) and the second piston assembly (38), respectively; The undercarriage system (18) of claim 6, wherein the conduit (46) extends through each of the upper arm (56) and the lower arm (58).

8. A method for adjusting the height of an idler (30) in an undercarriage system (18) according to any one of claims 5 to 7, comprising: opening a fluid transfer valve (48) in a conduit (46) extending between a first piston assembly (34) supported on an upper side (75) of the idler support element (44) of the undercarriage system (18) and a second piston assembly (38) supported on a lower side (77) of the idler support element (44); repositioning the idler support element (44) relative to a track roller frame (22) in the undercarriage system (18) while the fluid transfer valve (48) is open; co-varying positions of pistons (36, 40) in the first piston assembly (34) and the second piston assembly (38) based on repositioning of the idler support element (44); displacing a flowable material through the conduit (46) based on the co-variation of the positions of the pistons (36, 40); and closing the fluid movement valve (48) to set the height of the idler (30) along with the displacement of the flowable material.

9. further comprising positioning a track (20) of the undercarriage system (18) on a calibration block (110) placed on a base plate such that the rotation axis of the idler (30) is positioned vertically above the idler support block; the conduit (46) is a closed conduit and displacing the flowable material comprises displacing grease; 9. The method of claim 8 when dependent on claim 7, wherein opening the fluid transfer valve (48) and closing the fluid transfer valve (48) includes adjusting the fluid transfer valve (48) using an external handle (72).

10. 10. The method of claim 9, wherein repositioning the idler support element (44) comprises lowering the idler support block in the undercarriage system (18) or lowering a track roller frame (22) under gravity toward the calibration block (110).

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