Link device and crawler

Abstract

To provide a link device which can form a link at low costs and properly seal a lubricant, and to provide a crawler including the link device.SOLUTION: In a link device 12, a fitting part 45 to which a seal member 43 is fitted is formed in at least one of an end part of a bush 21 and an area around a second hole part 36 of a link 20 which faces the end part of the bush 21 while forming a gap 46 therebetween. Deformation in an axial direction of the seal member 43 fitted in the fitting part 45 allows the end part of the bush 21 to be supported by a support member which is harder than the seal member 43.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a link device in which a plurality of links are connected via bushes and pins, and to a crawler belt including the link device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in crawlers used in crawler vehicles such as hydraulic excavators, a link device is used in which a plurality of links are endlessly connected via bushes and pins (see, for example, Patent Documents 1 and 2).

[0003] In order to extend the life of the link device, it is common to fill the gap between the pin and the bush with a lubricant such as grease or lubricating oil. In order to prevent soil contamination due to leakage of the lubricant, it is necessary to provide a sealing means at the end of the contact surface between the pin and the bush.

[0004] A typical sealing means, as described in Patent Document 1, for example, involves providing a countersunk portion with a larger diameter than the pin on the inner periphery of the pin hole in the link, attaching a seal member with a W-shaped cross section to the countersunk portion, and positioning the entire end of the bushing so that it comes into contact with the seal member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-86317 [Patent Document 2] Japanese Patent Application Publication No. 8-324466 Summary of the Invention [Problem to be solved by the invention]

[0006] In the above structure, a depth is required for the countersunk portion in which the bushing is to be mounted, and a pin press-fit allowance is required for press-fitting the pin into the link, so thickness is required around the pin hole in the link.

[0007] For example, as in the configuration described in Patent Document 1, when the base material of the link is manufactured by a method such as forging or casting, it is possible to form a mountain-shaped boss portion in which the area around the pin hole is partially thick, but when the link is manufactured from rolled material as in Patent Document 2, it is not possible to thicken only the area around the pin hole, and the rolled material as a whole becomes thick, which increases the volume of the base material and increases the cost. In addition, in the case of a seal member with a W-shaped cross section, the structure is such that it bears all the load in the direction of the rotation axis of the link, so not only is it unavoidable for it to be large, but the seal member is also susceptible to wear, which is one of the factors that affect the life of the link device.

[0008] The present invention has been made in consideration of the above-mentioned points, and has an object to provide a link device that enables links to be formed at low cost and that can adequately seal lubricant, and a crawler belt including the link device. [Means for solving the problem]

[0009] The invention described in claim 1 is a link device comprising: a plurality of links formed from rolled material and having a plurality of holes; a bushing pressed into the hole of the links; a pin that connects one link to another by being pressed into the hole of the other link through the bushing pressed into the hole of the first link; and an annular sealing member that seals in lubricant interposed between the pin and the bushing, wherein an attachment portion into which the sealing member is fitted is formed in at least one of the end of the bushing and the periphery of the hole of the link facing the end of the bushing across a gap, and the end of the bushing can be supported by a support member harder than the sealing member due to axial deformation of the sealing member fitted into the attachment portion.

[0010] The invention as set forth in claim 2 provides a link device as set forth in claim 1, wherein the fitting portion is a groove portion formed on at least one of an end face of the bush and a side surface portion around the hole portion of the link.

[0011] The invention recited in claim 3 provides the link device recited in claim 1, wherein the fitting portion is a chamfered portion formed on at least one of an edge of a hole in the bush and an edge of a hole in the link.

[0012] The invention described in claim 4 is a crawler belt comprising a link device described in any one of claims 1 to 3 in which a plurality of links are endlessly connected via bushes and pins, and shoes attached to each link of the link device. Effect of the Invention

[0013] According to the invention as recited in claim 1, the link can be formed at low cost and the lubricant can be appropriately sealed.

[0014] According to the invention described in claim 2, the fitting portion can be easily formed, and by setting the shape of the fitting portion and the allowable deformation amount of the sealing member, a configuration can be easily realized in which the end of the bush and the support member can be brought into contact by axial deformation of the sealing member fitted into the fitting portion.

[0015] According to the invention described in claim 3, the fitting portion can be easily formed, and by setting the shape of the fitting portion and the allowable deformation amount of the sealing member, a configuration can be easily realized in which the end of the bush and the support member can be brought into contact by axial deformation of the sealing member fitted into the fitting portion.

[0016] According to the invention as recited in claim 4, it is possible to provide a highly reliable crawler which is inexpensive and capable of maintaining its performance for a long period of time. [Brief description of the drawings]

[0017] [Figure 1] 1 is a vertical sectional front view showing a first embodiment of a link device and a crawler belt including the link device according to the present invention. [Diagram 2] 4A is an enlarged longitudinal sectional front view of a portion of the link device, and FIG. 4B is a longitudinal sectional front view showing a state in which a bush and a support member come into contact with each other due to deformation of a seal member. [Diagram 3]FIG. 2A is a perspective view showing the link from one side, and FIG. 2B is a perspective view showing the link from the other side. [Figure 4] FIG. [Diagram 5] FIG. 4 is a perspective view showing an example of a rolled material forming the link. [Figure 6] FIG. [Figure 7] FIG. 2 is a side view showing a tracked vehicle equipped with the track. [Figure 8] FIG. 6 is a vertical sectional front view showing a part of a second embodiment of a link device according to the present invention. [Figure 9] FIG. 11 is a vertical sectional front view showing a part of a third embodiment of a link device according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the present invention will be described in detail based on a first embodiment shown in FIGS. 1 to 7, a second embodiment shown in FIG. 8, and a third embodiment shown in FIG.

[0019] First, the embodiment shown in FIGS. 1 to 7 will be described.

[0020] In Fig. 7, reference numeral 1 denotes a tracked vehicle. In this embodiment, a hydraulic excavator, which is a work machine, is taken as an example of the tracked vehicle 1. In the tracked vehicle 1, an upper rotating body 3 is provided rotatably with respect to a lower traveling device 2, and a work device 4, a cab 5 in which an operator sits, and the like are mounted on the upper rotating body 3.

[0021] The traveling device 2 has a track frame 6 provided on the left and right sides of the body, one end of which is supported by a sprocket 7 driven by a traveling motor, and the other end of which is supported by an idler 8 for free rotation, and the lower part is supported by a plurality of lower rollers 9 for free rotation, and the upper part is supported by a plurality of upper rollers 10 for free rotation, and a track 11 is wrapped around the sprockets 7, idlers 8, lower rollers 9 and upper rollers 10 on the left and right sides of the body.

[0022] As shown in Fig. 6, the crawler belt 11 is configured by hanging and attaching a shoe (shoe plate) 13, which is a rotating member, across an endless link device 12 that is configured symmetrically or approximately symmetrically. The shoe 13 is configured to be rotated by the link device 12.

[0023] The link device 12 is configured by connecting a plurality of plate-like links (track links) 20 by cylindrical bushes 21 and columnar pins 22. In this embodiment, the plurality of links 20 are connected in sequence at both ends of the bushes 21 and the pins 22. Thus, one link 20, 20 forming a left-right pair is connected to another link 20, 20 forming a left-right pair by the bushes 21 and the pins 22. That is, in the illustrated example, one row of link devices 12 is set for each shoe 13 in the center of the shoe 13 in the left-right direction.

[0024] The link 20 shown in FIG. 3(a) and FIG. 3(b) is arranged with the thickness direction as the left-right direction, the longitudinal direction as the front-rear direction, and the short side direction or width direction as the up-down direction. The link 20 has a flat link body 24 having the greatest thickness, and a flat first connecting portion 25 and a second connecting portion 26 having a thickness smaller than that of the link body 24. The first connecting portion 25 and the second connecting portion 26 are located on opposite sides of each other with respect to the link body 24. The first connecting portion 25 constitutes one end of the link 20, and the second connecting portion 26 constitutes the other end of the link 20. In this embodiment, the first connecting portion 25 is offset in a step-like manner to one side in the thickness direction with respect to the link body 24, and the second connecting portion 26 is offset in a step-like manner to the other side in the thickness direction. That is, the first connecting portion 25 and the second connecting portion 26 are alternately arranged in the thickness direction with respect to the link body 24. The link 20 is vertically symmetrical or approximately symmetrical, and the left and right links 20 are formed to have the same shape.

[0025] As shown in FIG. 4, the link body 24 is a portion that connects the link device 12 or the link 20 to the shoe 13. In this embodiment, the link 20 and the shoe 13 are connected to each other by a mounting bolt 27 that is a connecting member. For example, the link body 24 is formed with a bolt hole 28 having a threaded portion therein, into which the mounting bolt 27 is screwed, from the bottom to the top along the vertical direction that is a direction perpendicular to the rotation axis direction of the link 20. In the illustrated example, the bolt hole 28 is formed on the first connecting portion 25 side, i.e., one end side, and the second connecting portion 26 side, i.e., the other end side, of the link body 24. The mounting bolt 27 is inserted from a mounting hole 29 formed in the shoe 13 and inserted into the bolt hole 28 and screwed, thereby connecting the link 20 and the shoe 13 to each other. The connecting structure between the link 20 and the shoe 13 can be configured arbitrarily, and is not limited to the one that uses the mounting bolt 27 for connection, but may be, for example, a one that is connected by welding or the like.

[0026] 3(a), 3(b) and 6, the first connecting portion 25 is also called an inner connecting portion and is located on the inner side in the thickness direction of the multiple links 20 that are connected to each other. The second connecting portion 26 is also called an outer connecting portion and is located on the outer side in the thickness direction of the multiple links 20 that are connected to each other. In other words, among the connected links 20, the second connecting portion 26 of one link 20 is located on the outer side of the first connecting portion 25 of the other link 20, overlapping each other.

[0027] A first hole 35, into which the bushing 21 is press-fitted, is formed in the first connecting portion 25. The first hole 35 is formed in a circular shape and penetrates the first connecting portion 25 in the thickness direction. The first hole 35 has a slight press-fit allowance with respect to the outer diameter of the bushing 21. In other words, the first connecting portion 25 is formed to a thickness that ensures a press-fit allowance for the bushing 21, and has a substantially constant thickness.

[0028] The second connecting portion 26 is formed with a second hole portion 36, which is a hole portion into which the pin 22 is press-fitted. The second hole portion 36 is formed in a circular shape and penetrates the second connecting portion 26 in the thickness direction. The second hole portion 36 has a slight press-fit allowance with respect to the outer diameter of the pin 22. In other words, the second connecting portion 26 is formed with a thickness that can ensure the press-fit allowance of the pin 22, and has a substantially constant thickness. In this embodiment, the thickness of the second connecting portion 26 is set to be larger than the thickness of the first connecting portion 25.

[0029] The second hole 36 is formed with a smaller diameter than the first hole 35. Around the second hole 36, a recess 38 into which the end of the bush 21 is inserted is formed in a stepped shape. The recess 38 is formed along the outer periphery of the second hole 36 on the inside of the second connecting portion 26, that is, on the side facing the first connecting portion 25 of the other link 20. The outer diameter of the recess 38 is formed slightly larger than the outer diameter of the bush 21. A bottom surface portion 39 of the recess 38 constitutes the side portion of the link 20 facing the end of the bush 21.

[0030] In this embodiment, the link 20 is formed by cutting out from a long rolled material 40 shown in Fig. 5. The step shape in the thickness direction between the link main body 24 and the first connecting portion 25 and second connecting portion 26 (Fig. 3(a)) is formed by rolling when the rolled material 40 is formed. The overall shape F of the link 20 can be obtained by simply cutting out only the peripheral portions from this rolled material 40 by laser cutting or punching, each of which corresponds to the height of the link 20 (Fig. 3(a)).

[0031] 3(a) and 3(b) may be machined before or after the link 20 is cut out from the rolled material 40 (FIG. 5). The bolt hole 28 shown in FIG. 4 is machined after the link 20 is cut out from the rolled material 40 (FIG. 5).

[0032] 1 is press-fitted across the first hole portions 35 of the left and right links 20. Both ends of the bush 35 protrude from the outer surfaces of the left and right links 20 and are inserted into the side portions of the links 20 that are overlapped on the outside of the links 20, that is, into recesses 38 in this embodiment.

[0033] The pin 22 is press-fitted between the second hole portions 36 of the links 20 that are stacked on the outside of the left and right links 20 through bushes 21 press-fitted into those links 20. The pin 22 is fitted into the bushes 21 with a gap therebetween, and a lubricant 42 such as grease or lubricating oil is interposed in the gap, and the gap is sealed with a seal member 43 to seal in the lubricant 42.

[0034] 1 and 2(a) is a seal ring formed into an annular shape by an elastic member. The seal member 43 is sandwiched between the end of the bush 21 and the periphery of the second hole 36 of the link 20, that is, the bottom surface 39 of the recess 38 in this embodiment.

[0035] The seal member 43 is fitted and held in the fitting portion 45. The fitting portion 45 is formed on at least one of the end of the bush 21 and the periphery of the second hole portion 36 of the link 20 facing the end of the bush 21 with a gap 46 therebetween, that is, the bottom surface portion 39 of the recess 38. For example, the fitting portion 45 is a groove portion formed on at least one of the end face of the bush 21 and the bottom surface portion 39 of the recess 38, which is the side surface portion around the second hole portion 36 of the link 20. In the illustrated example, the fitting portion 45 is formed on the end face of the bush 21. Also, the fitting portion 45 is recessed into the axial hole edge of the bush 21. Therefore, in this embodiment, one end of the seal member 43 fitted into the fitting portion 45 contacts the end or end face of the bush 21, the other end contacts the bottom surface portion 39 of the recess 38, and the inner peripheral portion contacts the outer peripheral surface of the pin 22.

[0036] When an axial load L is applied to a portion of the track 11, the sealing member 43 fitted into the fitting portion 45 deforms in the axial direction, causing the bushing 21 to shift laterally together with the link 20 by the amount of gap 46, so that, as shown in FIG. 2(b), the end or end face of the bushing 21 can come into contact with a support member other than the sealing member 43, such as, in this embodiment, the bottom portion 39 of the recess 38 around the second hole portion 36 of the link 20.

[0037] Therefore, the seal member 43 preferably has a cross-sectional shape with a large allowable deformation amount (crush allowance). For example, in the present embodiment, the seal member 43 has an O-shaped cross section. However, the seal member 43 may have a D-shaped or X-shaped cross section.

[0038] The depth and width of the fitting portion 45 are sized to fully allow the deformation of the fitted seal member 43. For example, if the depth of the fitting portion 45 is too large, the seal member 43 does not properly contact the end or end face of the bush 21 and the bottom surface portion 39 of the recess 38, and the sealability cannot be maintained. If the width of the fitting portion 45 is insufficient, the deformation of the seal member 43 is limited, and the seal member 43 cannot be sufficiently crushed when an axial force is applied to the crawler belt 11, and the end of the bush 21 cannot be brought into contact with the bottom surface portion 39 of the recess 38. In this embodiment, the gap 46 is set to, for example, about 0.5 mm. Therefore, the shape of the seal member 43 and the fitting portion 45 is set so that the allowable axial deformation of the seal member 43 is 0.5 mm or more.

[0039] In this manner, in this embodiment, the fitting portion 45 into which the annular seal member 43 that seals the lubricant 42 interposed between the pin 22 and the bush 21 is fitted is formed in at least one of the end of the bush 21 and the periphery of the second hole portion 36 of the link 20 that faces the end of the bush 21 via a gap 46, and the end or end face of the bush 21 can be supported in the axial direction by a support member harder than the seal member 43, for example, the periphery of the second hole portion 36 of the link 20, due to the axial deformation of the seal member 43 fitted into the fitting portion 45. Since the link 20 does not have substantial elasticity, in this embodiment, the contact between the end or end face of the bush 21 and the periphery of the second hole portion 36 of the link 20 is non-elastic contact. However, the support member may have elasticity as long as it is harder than the seal member 43 and less likely to deform than the seal member 43.

[0040] Therefore, when the load L is applied to the link device 12 or the crawler belt 11 in the axial direction, the load L is not received by the seal member 43 alone, so that the seal member 43 does not wear out even when it rotates in that state, and the lubricant 42 can be appropriately sealed while the seal member 43 can be made small. Therefore, there is no need to form a thick mountain-shaped boss part partially around the second hole part 36 of the link 20 to hold the seal member 43, and the sealing function of the seal member 43 can be maintained for a long period of time, and the link 20 can be formed to be thin and lightweight overall. Therefore, the link 20 can be formed using the rolled material 39 as the base material, so that durability and productivity can be improved, processing costs can be suppressed, and the rolled material 39 can be made thin, so that the material costs can be suppressed, and therefore a low-cost link 20 can be provided.

[0041] Furthermore, by using a sealing member 43 having an O-shaped, D-shaped, X-shaped or other cross section which has a larger crushing allowance compared to a W-shaped cross section, even when an axial load L is applied, the sealing member 43 will not reach the allowable deformation and wear out before the end of the bush 21 comes into contact with the periphery of the second hole portion 36 of the link 20.

[0042] Furthermore, by making the link 20 symmetrical or nearly symmetrical from top to bottom, except for the bolt hole portions 28 which can be post-machined, it is possible to process both the left and right links 20 from the same rolled material 39. This eliminates the need to prepare dedicated rolled materials for each of the left and right links 20, further reducing costs.

[0043] By making the fitting portion 45 a groove portion formed in at least one of the end face of the bushing 21 and the bottom surface portion 39 of the recess 38 around the second hole portion 36 of the link 20, the fitting portion 45 can be easily formed, and by setting the shape of the fitting portion 45 and the allowable deformation amount of the sealing member 43, a configuration can be easily realized in which the axial deformation of the sealing member 43 fitted into the fitting portion 45 allows contact between the end or end face of the bushing 21 and the periphery of the second hole portion 36 of the link 20.

[0044] Furthermore, by providing the crawler belt 11 with the above-mentioned link device 12 and shoes 13 attached to each link 20 of the link device 12, it is possible to provide a crawler belt 11 that is inexpensive, can maintain its performance over a long period of time, and is highly reliable.

[0045] In addition, in a typical link, a mud drain hole is provided in the center of the link body, a bolt insertion hole is provided that penetrates to the mud drain hole, and a mounting bolt for fixing the shoe is inserted into the mounting hole in the shoe and the bolt insertion hole in the link, and a nut is fastened at the mud drain hole portion, but while a mud drain hole can be easily provided by punching or the like in a link for a relatively small tracked vehicle due to its thickness, punching is difficult to use in the case of a link for a relatively large tracked vehicle due to its thickness. In this embodiment, a bolt hole portion 28 is formed in a direction perpendicular to the rotation axis direction of the link 20, and a mounting bolt 27 inserted from a mounting hole 29 in the shoe 13 is screwed into the bolt hole portion 28, so that the shoe 13 can be easily attached to the link 20 even in a track 11 for a large tracked vehicle for which it is difficult to punch a mud drain hole in the link 20.

[0046] Next, an embodiment shown in Fig. 8 will be described. Note that the same parts as those in the embodiment shown in Fig. 1 to Fig. 7 are given the same reference numerals and the description will be simplified.

[0047] In this embodiment, the fitting portion 45 is a groove portion formed around the second hole portion 36 of the link 20, i.e., on the bottom surface portion 39 of the recess 38. The fitting portion 45 is located at a position radially spaced apart from the periphery of the shaft hole of the bushing 21 and the edge of the second hole portion 36.

[0048] In this way, the fitting portion 45 into which the annular sealing member 43 that seals the lubricant 42 interposed between the pin 22 and the bush 21 is fitted is formed in at least one of the end of the bush 21 and the periphery of the second hole portion 36 of the link 20 that faces the end of the bush 21 via a gap 46, and the end of the bush 21 can be supported by the periphery of the second hole portion 36 of the link 20 by axial deformation of the sealing member 43 fitted into the fitting portion 45. By having a configuration similar to that of the first embodiment, the link 20 can be formed at low cost and the same effects as the first embodiment can be achieved, such as being able to properly seal the lubricant 42.

[0049] Next, a description will be given of the embodiment shown in Fig. 9. Note that the same parts as those in the respective embodiments are given the same reference numerals and the description will be simplified.

[0050] In this embodiment, the fitting portion 45 is a chamfered portion formed on at least one of the edge of the hole of the bushing 21 and the edge of the second hole portion 36 of the link 20. In the example shown in the figure, the fitting portion 45 is formed mainly as a large chamfered portion on the edge of the hole of the bushing 21 and a small chamfered portion on the edge of the second hole portion 36 of the link 20, and these are connected to form a triangular cross section.

[0051] Thus, the seal member 43 comes into contact at three positions: the chamfered surface of the edge of the second hole portion 36 of the link 20 and the end face of the bush 21, the side surface around the second hole portion 36 of the link 20 and the chamfered surface of the shaft hole edge of the bush 21, or the chamfered surface of the edge of the second hole portion 36 of the link 20 and the chamfered surface of the shaft hole edge of the bush 21, and any of these with the outer circumferential surface of the pin 22. The size of the triangular gap created by the chamfering of the fitting portion 45 is set to a dimension that sufficiently allows deformation of the fitted seal member 43.

[0052] In this way, the fitting portion 45 into which the annular sealing member 43 that seals the lubricant 42 interposed between the pin 22 and the bush 21 is fitted is formed in at least one of the end of the bush 21 and the periphery of the second hole portion 36 of the link 20 that faces the end of the bush 21 via a gap 46, and the end of the bush 21 can be supported by the periphery of the second hole portion 36 of the link 20 by axial deformation of the sealing member 43 fitted into the fitting portion 45. By having a configuration similar to that of the first embodiment, the link 20 can be formed at low cost and the same effects as the first embodiment can be achieved, such as being able to properly seal the lubricant 42.

[0053] Furthermore, by making the fitting portion 45 a chamfered portion formed on at least one of the edge of the hole portion of the bushing 21 and the edge of the second hole portion 36 of the link 20, the fitting portion 45 can be easily formed, and by setting the shape of the fitting portion 45 and the allowable deformation amount of the sealing member 43, a configuration can be easily realized in which the axial deformation of the sealing member 43 fitted into the fitting portion 45 allows contact between the end or end face of the bushing 21 and the periphery of the second hole portion 36 of the link 20.

[0054] In addition to the above-described embodiments, the fitting portion 45 may be formed into any shape that allows the fitted sealing member 43 to contact the end of the bush 21 and the periphery of the second hole portion 36 of the link 20, and that allows the sealing member 43 to deform sufficiently in the axial direction so that the end of the bush 21 can be supported by the periphery of the second hole portion 36 of the link 20 due to an axial load L.

[0055] Furthermore, the support member that supports the end of the bushing 21 when the seal member 43 is deformed by the axial load L does not have to be the link 20, and may be, for example, a separate washer disposed around the second hole 36 of the link 20, as long as it is a member harder than the seal member 43, i.e., does not substantially deform significantly due to the load L. In other words, the configuration is not limited to the periphery of the second hole 36 of the link 20 directly contacting and supporting the end of the bushing 21, and the periphery of the second hole 36 of the link 20 may indirectly support the end of the bushing 21 via the support member. By making the support member a member harder than the seal member 43 and contacting the end of the bushing 21 when the seal member 43 is deformed by the axial load L, it is possible to achieve the same effects as those of the respective embodiments.

[0056] Furthermore, the link device 12 is formed endless by sequentially connecting links 20 of the same shape, but this is not limiting, and one link 20 to which the bush 21 is fitted and another link 20 to which the pin 22 is press-fitted may be formed separately. In this case, the first link 20 has a plurality of first holes 35 formed therein, and the other link 20 has a plurality of second holes 36 formed therein.

[0057] Furthermore, the shoe 13 and the link 20 may be connected by fastening with nuts using mounting bolts through typical mud drainage holes and bolt insertion holes, or by welding.

[0058] The link device 12 is suitable for the crawler belt 11, but can also be applied to other than crawler belts. For example, a conveyor device can be configured by attaching rotating members such as a conveyor plate and a conveyor bar to the links 20 of the link devices 12 connected in an endless manner. [Industrial Applicability]

[0059] The present invention can be utilized in industries that manufacture and sell tracks and link devices used in tracked vehicles such as work machines. [Explanation of symbols]

[0060] 11 Tracks 12 Link device 13. Shoe 20 Links 21 Bush 22 pin 35 First hole portion 36 Second hole part 40 Rolled material 42 Lubricants 43 Sealing material 45 Fitting part 46 Gap

Claims

1. A plurality of links formed from a rolled material and having a plurality of holes; A bushing is press-fitted into the hole of the link; a pin that is press-fitted into a hole of one link through a bush that is press-fitted into a hole of the other link, thereby connecting the first link and the other link; an annular seal member that seals in the lubricant between the pin and the bush; a fitting portion into which a seal member is fitted is formed on at least one of an end portion of the bush and a periphery of a hole portion of the link facing the end portion of the bush with a gap therebetween; The end of the bushing can be supported by a support member that is harder than the seal member due to axial deformation of the seal member that is fitted in the fitting portion. A link device comprising:

2. The fitting portion is a groove formed on at least one of the end face of the bush and the side surface around the hole of the link.

2. The link device according to claim 1.

3. The fitting portion is a chamfered portion formed on at least one of the edge of the hole of the bush and the edge of the hole of the link.

2. The link device according to claim 1.

4. 4. A link device according to claim 1, in which a plurality of links are connected in an endless manner via bushes and pins; A shoe attached to each link of the link device; A track comprising:

Images