Track link assembly, track system and construction machine

Abstract

The present disclosure relates to a track link assembly, a track system (110) and a construction machine (100) comprising the track link assembly. The track link assembly comprises a left track link (1), a right track link (2), two bushings (3), and a pin shaft (4) connecting the left track link (1) and the right track link (2). The left track link (1) has a first left hole(ll) and a second left hole (13). The right track link (2) has a first right hole (21) and a second right hole (23). The two bushings (3) are respectively installed in the second left hole (13) and the second right hole (23). The pin shaft (4) comprises a middle section (41) as well as first and second sections (42,43) located at opposite sides of the middle section (41). The first and second sections (42,43) are inserted through the first left hole (11) and the first right hole (21) respectively in an interference fit manner, and are intended to be engaged with two bushings (13) of another track link assembly in a clearance fit manner. The middle section (41) has a protrusion (411) configured to engage with a driving wheel of a construction machine. In the track link assembly of the present disclosure, the protrusion (411) is used to directly engaged with the driving wheel of the construction machine, thus decreasing manufacturing steps of the track system and even of the construction machine, and thereby reducing the manufacturing cost.

Description

[0001] Description

[0002] TRACK LINK ASSEMBLY, TRACK SYSTEM AND CONSTRUCTION MACHINE

[0003] Technical Field

[0004] The present disclosure relates generally to a ground-engaging track / crawler system of a construction machine, and more particularly to a track link assembly for the track system.

[0005] Background Art

[0006] The track or crawler is often used in a construction machine, e.g. a bulldozer or an excavator as a ground-engaging propulsion element. The track typically comprises multiple pairs of track links connected in a ring, and track shoes fixed onto these track links. Each pair of track links includes a left track link and a right track link arranged mirror-symmetrically. The two track links are connected with each other via a pin shaft, and intended to connect an adjacent pair of track links.

[0007] In known track, the symmetrically arranged left track link and right track link are connected at one end via a pin sleeve fixed in their respective pin sleeve holes, and the pin shaft can be inserted through the pin sleeve. The other ends of the left track link and the right track link are respectively provided with a through hole, and the pin shaft extends from opposite ends of the pin sleeve and passes through the through holes for connecting a pair of adjacent track links. However, the structure of track links, pin shaft and pin sleeve can't directly engage with the driving wheel of the construction machine. Rather, an additional component must be provided on the basis of this structure to engage with the driving wheel, making the manufacturing process of the track complicated and resulting in an extremely high cost.

[0008] In addition, in the prior art, the pin sleeve holes penetrate through the left track link and the right track link. As a result, the lubricating oil between the pin sleeve and the pin shaft is easy to run off during long-term use of the track, making the lubricating effect decline over time.

[0009] Summary of the Invention

[0010] It is an object of the present disclosure to solve at least one of the above problems and / or other problems existing in the prior art.

[0011] In one aspect, the present disclosure provides a track link assembly, which comprises a left track link, a right track link, two bushings and a pin shaft connecting the left track link and the right track link. The left track link comprises a first left segment having a first left hole, and a second left segment having a second left hole and connected to the first left segment. The right track link comprises a first right segment having a first right hole, and a second right segment having a second right hole and connected to the first right segment. The left track link and the right track link are configured and arranged in a mirrorimage symmetrical manner such that a distance between the first left segment and the first right segment is smaller than a distance between the second left segment and the second right segment. The two bushings are respectively installed in the second left hole and the second right hole. The pin shaft comprises a middle section, a first section and a second section located at either side of the middle section. The first section and the second section are inserted in the first left hole and the first right hole respectively in an interference fit manner, and are configured to be engaged with two bushings of another track link assembly in a clearance fit manner. The middle section of the pin shaft has a protrusion protruding outward perpendicular to a central axis of the pin shaft, and the protrusion is configured to be engaged with a driving wheel of a construction machine.

[0012] In the track link assembly of the present disclosure, the left track link and the right track link are connected by a special-shaped pin shaft with a protrusion formed at its middle section, and the protrusion of the special-shaped pin shaft can be directly engaged with gear teeth of the driving wheel of the construction machine, without the need of providing other features on the track system for engaging with the driving wheel of the construction machine. This will decrease the manufacturing steps of the track system or even of the entire construction machine, thereby reducing the manufacturing cost. This solution is especially suitable for the working conditions of small and medium-sized construction machines, such as excavators.

[0013] In addition, in the disclosed track link assembly, the holes for receiving the two bushings, i.e., the second left hole of the left track link and the second right hole of the right track link, can be constructed as blind holes, thereby end-face enclosed structures can be formed. In this way, after the pin shaft is fitted into the shaft sleeve, a sealed lubrication cavity can be formed by means of a sealing ring, which will reduce the loss of lubrication medium between the pin sleeve and the pin shaft, and avoid deterioration of the lubrication effect.

[0014] In another aspect, the present disclosure provides a track system comprising track link assemblies as described above, which are connected in series with each other.

[0015] In yet another aspect, the present disclosure provides a construction machine, which comprises the track link assembly or track system as described above.

[0016] Brief Description of the Drawings

[0017] The features and advantages of the present disclosure are described in detail below to give a clear interpretation with reference to the accompanying drawings. It will be appreciated that the following drawings are only schematic and not necessarily drawn to scale, and therefore cannot be regarded as limiting the invention.

[0018] Fig. l is a side view of a construction machine according to an exemplary embodiment of the present disclosure.

[0019] Fig. 2 is a perspective view of a track link assembly according to an exemplary embodiment of the present disclosure. Fig. 3 is a perspective view of a pin shaft of a track link assembly shown in fig. 2.

[0020] Fig. 4 is a sectional top view of track link assemblies which are connected in series to form a ring.

[0021] Fig. 5 is a cross-sectional view of the track link assembly shown in fig. 4 taken along a line A-A.

[0022] Detailed Description of the Embodiments

[0023] Embodiments of the present disclosure are described below with reference to the drawings. In the following description, numerous specific details are set forth in order to make those skilled in the art fully understand and implement the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure may be implemented without some of these specific details. Furthermore, it will be appreciated that the present disclosure is not limited to the specific embodiments described. On the contrary, any combination of features and elements described below can be used to implement the invention, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments and advantages are for illustration only, and should not be regarded as elements or limitations of the claims, unless explicitly stated in the claims.

[0024] Terms such as "first" and "second" are used herein to describe the elements of the present disclosure, but they are only used to distinguish individual elements, and are not used to limit the nature, order or number of the elements. The terms "comprise", "include", and “have” are used to indicate an open-ended inclusion, and mean that there may be other elements / components besides the listed elements / components.

[0025] Fig. 1 shows a construction machine 100 including a crawler-type grounded propulsion element. The construction machine 100 is shown as a crawler tractor, but it may also be a crawler excavator, loader or any of a variety of other machines. The construction machine 100 may include a track system 110, and the track system 110 shown in the figure may be one of two separate track systems arranged at two opposite sides of a frame 120 of the construction machine 100 in a conventional manner. The track system 110 may include a track roller frame 130 connected to the frame 120 and a plurality of rotatable track engaging elements 140, 150 and 160. In one embodiment, the track engaging elements 140 and 150 may be rotatable idlers that passively rotate during the operation of the track system 110, and the track engaging element 160 may be a driving wheel for driving the track system 110, which may have teeth for engagement and especially for being inserted between track links of the track system. The track system 110 may also include a plurality of track rollers 170 mounted to the track roller frame 130. The track system 110 may also include a track 180 extending around the track engaging elements 140, 150, and 160 and the track roller 170. The track 180 may include a plurality of paired track links and a plurality of track shoes 181 connected with the paired track links. The track roller 170 may bear against the left track link 1 and / or the right track link 2 adjacent thereto.

[0026] Fig. 2 shows a track link assembly according to one embodiment of the present disclosure. The track link assembly according to this embodiment mainly includes a left track link 1, a right track link 2, two bushings 3, and a pin shaft 4 that connects the left track link 1 and the right track link 2. The track link assembly can be connected with another track link assembly of the same structure via the pin shaft 4. Taking the plane perpendicular to the central axis of the pin shaft 4 as a symmetry plane, the right track link 2 and the left track link 1 are arranged in a mirror-image symmetrical manner.

[0027] Referring to figs. 2 and 4, the left track link 1 may include a first left segment 12 and a second left segment 14 extending in a substantially longitudinal direction (i.e., the traveling direction of the construction machine, the left-right direction in fig. 2). The second left segment 14 is connected to the first left segment 12. The two left segments may be connected by a connecting plate or may be integrally formed. The first left segment 12 and the second left segment 14 are offset with respect to each other in a lateral direction (i.e., the up- and-down direction in fig. 2) perpendicular to the longitudinal direction, so that the left track link 1 as a whole presents a roughly inverted Z-shaped outline. On this basis, the left track link 1 may further include a middle left segment connected between the first left segment 12 and the second left segment 14, and the middle left segment has approximately flat upper and lower surfaces (upward and downward surfaces in fig. 2) to combine with the track roller 170 and the track shoe 181, respectively. The first left segment 12 and the second left segment 14 are respectively provided with a first left hole 11 for the passage of the pin shaft 4 and a second left hole 13 for the passage of a pin shaft 4 of another adjacent track link assembly.

[0028] With continued reference to figs. 2 and 4, the right track link 2 may also include a first right segment 22 and a second right segment 24 extending substantially in the longitudinal direction and connected with each other. Similar to the configurations of the first left segment 12 and the second left segment 14, the first right segment 22 and the second right segment 24 are offset relative to each other in the lateral direction, so that the right track link 2 as a whole presents a roughly Z-shaped outline. Similarly, the right track link 2 may further include a middle right segment connected between the first right segment 22 and the second right segment 24, which has approximately flat upper and lower surfaces to combine with the track roller 170 and the track shoe 181, respectively. The first right segment 22 and the second right segment 24 are respectively provided with a first right hole 21 for the passage of the pin shaft 4 and a second right hole 23 for the passage of a pin shaft 4 of another adjacent track link assembly.

[0029] Heare, it should be pointed out that the left track link 1 and the right track link 2 may also be constructed without the middle left segment and the middle right segment, but only include the first and second left segments 12, 14 as well as the first and second right segments 22, 24, which smoothly extends from the middle part of the respective left and right track links 1, 2 to both of their ends in the longitudinal direction. The first left segment 12 and the second left segment 14 smoothly transition toward and away from the right track link 2 respectively relative to the middle part of the left track link 1; while the first right segment 22 and the second right segment 24 smoothly transition toward and away from the left track link 1 respectively relative to the middle part of the right track link 2.

[0030] As shown in figs. 2 and 4, in the track link assembly of this embodiment, the second left segment 14 of the left track link 1 is offset away from the right track link 2 on the left side of the first left segment 12, while the second right segment 24 of the right track link 2 is offset away from the left track link 1 on the left side of the first right segment 22, so that the distance between the first left segment 12 and the first right segment 22 is smaller than that between the second left segment 14 and the second right segment 24.

[0031] With continued reference to figs. 2 and 4, the first left segment 12 has a first left hole 11, and the second left segment 14 has a second left hole 13. The first right segment 22 has a first right hole 21, and the second right segment 24 has a second right hole 23. The two bushings 3 are installed in the second left hole 13 and the second right hole 23 respectively. When the left track link 1 and the right track link 2 are arranged in a mirror-image symmetrical manner, the second left hole 13 and the second right hole 23 are also in mirror symmetry, and accordingly the two bushings 3 are also in mirror symmetry. The diameters of the second left hole 13 and the second right hole 23 can be designed to allow the bushings 3 to be fixed therein in a press-fit manner. Preferably, axial dimensions of the bushings 3 are less than or equal to those of the corresponding second left hole 13 or the second right hole 23.

[0032] According to an exemplary embodiment of the present disclosure, as shown in figs. 2 to 4, the pin shaft 4 includes a middle section 41, and a first section 42 and a second section 43 located at either side of the middle section 41. Outer diameters of the first section 42 and the second section 43 can be slightly larger than inner diameters of the bushings 3, so that two bushings 3 of another track link assembly can be engaged with the first section 42 and the second section 43 in a clearance fit manner.

[0033] Advantageously, the middle section 41 of the pin shaft 4 has a protrusion 411 protruding outward and perpendicular to the central axis of the pin shaft 4, and the protrusion 411 is configured to be engaged with the driving wheel of the construction machine. In this case, the middle section 41 further includes a groove 412 located opposite the protrusion 411, which can be positioned on the same diameter of the pin shaft 4 as the protrusion 411.

[0034] Preferably, the groove 412 and the protrusion 411 are formed by forging the middle section 41 in a direction perpendicular to the central axis of the pin shaft 4. To this end, the pin shaft 4 can be placed between an upper and lower anvils of a forging device, and an external force perpendicular to the central axis of the pin shaft 4 can be directly applied to the pin shaft 4, so that the middle section 41 of the pin shaft 4 can form a groove 412 and a protrusion 411 along the direction in which the external force is applied. This can also be called free forging process. In this embodiment, the teeth of the driving wheel can be engaged in the groove 412 in one-to-one correspondence, or two adjacent teeth can be engaged with the protrusion 411.

[0035] Alternatively, the groove 412 and the protrusion 411 can be formed not to be aligned on the same diameter of the pin shaft 4, while the formation of the protrusion 411 and the groove 412 includes but is not limited to the forging process described above.

[0036] Preferably, the first section 42 of the pin shaft 4 may include a first inner section and a first outer section which are successively connected, in which the first inner section is adjacent to the middle section 41 and used for interference-fit connection with the first left segment 12 of one track link assembly, and the first outer section is used for clearance-fit connection with the bushing 3 in the second left hole 13 of another track link assembly. Accordingly, diameters of the first inner section and the second inner section depend on the diameter of the first left hole of the left track link 1 and the inner diameter of the bushing 3 in the second left hole. The first inner section and the first outer section may have the same or different diameters. Similarly, the second section 43 may include a second inner section and a second outer section which are connected. Having a similar structure with the first section 42, it is not described in detail below. In a more preferred embodiment of the present disclosure, the second left hole 13 and the second right hole 23 are both configured as blind holes. The open end of the second left hole 13 faces the right track link 2, and the open end of the second right hole 23 faces the left track link 1. In this way, when the first section 42 and the second section 43 of the pin shaft 4 are inserted through the first left hole 11 and the first right hole 21 respectively to connect the left track link 1 and the right track link 2 so as to form a track link assembly, and are inserted into the second left hole and the second right hole of another track link assembly adjacent to said track link assembly (especially inserted into bushings 3 in these holes), closed gaps will be formed in the respective second left hole and second right hole. The gaps can be used to accommodate lubricating medium so as to lubricate the bushings 3 and the pin shaft 4 which can rotate relative to each other.

[0037] In a further preferred embodiment, the track link assembly further comprises two sealing rings 5. As shown in figs. 4 and 5, one sealing ring 5 (located on the left in fig. 5) is arranged at an axial end of the second left hole 13 facing the second right hole 23, and the other sealing ring 5 (located on the right in fig. 5) is arranged at an axial end of the second right hole 23 facing the second left hole 13. The two sealing rings 5 provided can seal the aforementioned gaps formed in the second left hole 13 and the second right hole 23 to prevent the lubricating medium in the gaps from escaping.

[0038] In a further preferred embodiment, with continued reference to figs. 4 and 5, the second left segment 14 of the left track link 1 is provided with a left sealing groove 141 for installing the sealing ring 5 at a position corresponding to the axial end of the second left hole 13, and the left sealing groove 141 is annular and coaxial with the second left hole 13. The sealing ring 5 can be made of silica gel, plastic or the like, and preferably has a W-shaped cross section, which may facilitate the elastic expansion and contraction along its axial direction. When the sealing ring 5 is disposed in the sealing groove, it will be deformed by the pressure from the first left segment (for the left track link) of another adjacent track link assembly, thereby ensuring reliable sealing. Similarly, the second right segment 24 is provided with a right sealing groove 241 for accommodating another sealing ring 5 at a position corresponding to the axial end of the second right hole 23. The structure of the right sealing groove 241 is similar to that of the left sealing groove 141, and will not be described in detail below.

[0039] The present disclosure also provides a track system and a construction machine comprising the track link assembly. The track system may include a plurality of track link assemblies as described above. These track link assemblies can be connected in series with each other. As shown in Fig. 4, the pin shaft 4 of the first track link assembly on the left is connected with the second left segment 14 and the second right segment 24 of the second track link assembly on the right adjacent to the first track link assembly, so as to form a long-chain track 180 rather than an annular track.

[0040] It should be emphasized that fig. 4 shows the configuration of joints of the long-chain annular track 180 at its both ends. The figure shows three pin shafts arranged from left to right, and the pin shaft in the middle is still constituted by a conventional pin shaft with a pin sleeve. The left track link and the right track link on opposite ends of this pin shaft may be in conventional structures (i.e., the second left hole of the left track link and the second right hole of the right track link are constructed as through holes). The conventional pin shaft can completely penetrate through the second left hole and the second right hole, then it easy for the disclosed left and right track links adjacent the center to be connected to the conventional pin sleeves, and the second left hole of the left track link and the second right hole of the right track link on the right to be aligned with the holes of the conventional pin sleeves, so that the pin shaft 4 can be directly pressed into the pin sleeve from the upper or lower side of fig. 4, and the long-chain track 180 can be conveniently constructed into an annular track 180. Industrial Applicability

[0041] The track link assembly according to the present disclosure is applicable to track-type construction machines, especially crawler-type tractors, excavators, loaders and other various construction machines that have to walk with the aid of a track system.

[0042] In the prior art, the pin shaft is arranged in the bushing between the first left segment and the first right segment, so that the pin shaft cannot directly engage with the driving wheel of the construction machine. In the present application, however, the first left segment 12 and the first right segment 22 are respectively fixed with the first section 42 and the second section 43 of the pin shaft 4 in an interference fit manner. With the bushing 3 arranged between the second left segment 14 and the pin shaft 4 and between the second right segment 24 and the pin shaft 4, the second left segment 14 and the second right segment 24 in the middle shown in fig. 4 can be respectively connected via the bushing 3 to the first section 42 and the second section 43 of an adjacent track link assembly on the left in a clearance fit manner. In this way, the track 180 can have a certain degree of freedom, and a space can be saved from the middle section 41 of the pin shaft 4, where a protrusion 411 and a groove 412 can be formed. One of the groove 412 and protrusion 411 is used for meshing with the teeth of the driving wheel to meet the rotation of the track. With the pin shaft and pin sleeve in the prior art replaced by this structure, the manufacturing steps can be decreased and the manufacturing cost can be reduced.

[0043] According to the present disclosure, the holes (i.e., the second left hole 13 and the second right hole 23) of the track link for accommodating the bushings are constructed as blind holes, thereby after the bushings 3 are installed in the holes in a press-fit manner and the pin shaft 4 is inserted into the bushing 3, spaces or gaps for accommodating the lubricating medium can be formed in these holes, so that the relatively rotatable bushing and pin shaft can be lubricated. Moreover, the sealing ring 5 ensures airtightness of the gaps, leading to a longterm lubrication effect on the bushings 3 and pin shaft 4. When the track 180 is assembled, a first track link assembly can be assembled first. That is to say, the protrusion 411 or groove 412 of the pin shaft 4 is oriented toward the teeth where a driving wheel needs to be connected, and the left track link 1 and the right track link 2 are respectively connected to the first section 42 and the second section 43 in an interference fit manner.

[0044] Then the second track link is assembled directly on the first track link assembly. That is, the second left hole 13 of the left track link 1 and the second right hole 23 of the right track link 2 of a second track link assembly are aligned with the first section 42 and the first section 42 of the pin shaft 4 of the first track link assembly respectively, and meanwhile the first section 42 of the pin shaft 4 of the second track link assembly is aligned with the first left hole 11 and the first right hole 21 of this track link assembly. A press machine is used to press the left track link 1 and right track link 2 onto the pin shaft 4 of the first track link assembly, and press the left track link 1 and right track link 2 onto the pin shaft 4 of the second track link assembly. In this way, a plurality of track link assemblies are connected to form a long-chain track 180. The last track link assembly of the track 180 has a conventional structure, that is, the second left hole of the left track link and the second right hole of the right track link are through holes, and the left track link and the right track link of the track link assembly are respectively connected with the pin sleeve in an interference fit manner, as shown in fig. 4.

[0045] Finally, the long-chain track 180 is used to form an annular track 180. The second left hole 13 and the second right hole 23 of the first track link assembly are aligned with the pin sleeve of the last conventional track link assembly. The conventional pin shaft is pressed, by a press machine, through the second left hole, the pin sleeve, and the second right hole of the first track link assembly sequentially, so that the conventional pin shaft is connected with the last conventional left track link and right track link in an interference fit manner, the pin sleeve is connected with the first pair of left track link and right track link in an interference fit manner, and the pin sleeve and pin shaft are connected in a clearance fit manner to ensure the degree of freedom of the track 180 in this connection.

[0046] Those skilled in the art can make various modifications and variations to the embodiments disclosed herein without departing from the scope or spirit of the present disclosure. Other embodiments of the invention will be apparent to those skilled in the art according to the practice of the invention disclosed in this specification. This specification and the examples disclosed herein are considered to be illustrative only, and the true scope of the invention is determined by the appended claims and their equivalents.

Claims

Claims1. A track link assembly, comprising: a left track link including a first left segment having a first left hole, and a second left segment having a second left hole and connected to the first left segment; a right track link including a first right segment having a first right hole, and a second right segment having a second right hole and connected to the first right segment, wherein the left track link and the right track link are configured and arranged in mirror-symmetry such that a distance between the first left segment and the first right segment is smaller than a distance between the second left segment and the second right segment; two bushings respectively installed in the second left hole and the second right hole; and a pin shaft connecting the left track link and the right track link, wherein the pin shaft comprises a middle section, and a first section and a second section located at opposite sides of the middle section, and wherein the first section and the second section are inserted through the first left hole and the first right hole respectively in an interference fit manner, and are configured to be engaged with two bushings of another track link assembly in a clearance fit manner, wherein the middle section has an outward protruding protrusion perpendicular to a central axis of the pin shaft, and the protrusion is configured for engaging with a driving wheel of a construction machine.

2. The track link assembly according to claim 1, characterized in that the middle section is further provided with a groove located opposite to the protrusion in a radial direction of the pin shaft.

3. The track link assembly according to claim 2, characterized in that the protrusion and the groove are formed by forging the middle section along a direction perpendicular to the central axis of the pin shaft.

4. The track link assembly according to any one of claims 1 to 3, characterized in that the second left hole and the second right hole are configured as blind holes.

5. The track link assembly according to claim 4, characterized in that the two bushings are respectively installed in the second left hole and the second right hole in a press-fit manner, and the axial dimensions of the two bushings are less than or equal to those of the corresponding second left hole or second right hole.

6. The track link assembly according to claim 5, characterized by further comprising two sealing rings, which are respectively arranged at a first left axial end of the second left hole toward the second right hole, and at a first right axial end of the second right hole toward the second left hole, so that sealed gaps are formed in the second left hole and the second right hole.

7. The track link assembly according to claim 6, characterized in that the second left segment is provided with a left sealing groove for installing one of the sealing rings at the first left axial end, and the second right segment is provided with a right sealing groove for installing the other sealing ring at the first right axial end.

8. The track link assembly according to claim 6, characterized in that the gaps are filled with lubricating medium.

9. A track system comprising a plurality of track link assemblies according to any one of claims 1 to 8, which are connected in series with each other.

10. A construction machine comprising a track link assembly according to any one of claims 1 to 8 or a track system according to claim 9.

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