Industrial vehicles

Abstract

The present invention provides an industrial vehicle that can absorb an axial gap between the center pin and the axle support that supports the axle using a simple elastic member, thereby suppressing axle movement and improving the reliability of the elastic member. [Solution] The center pin has a shaft portion 32 that is pivotally supported by a center pin support portion via a bush 51, and a flange portion 33 that extends radially outward from the end of the shaft portion and is fixed to the axle, and faces the end face of the center pin support portion in the front-rear direction. It also has an elastic member that eliminates the axial gap between the center pin support portion and the flange portion 33, and a grease supply passage that allows grease to be supplied from the outer circumferential surface of the bush 51 to the elastic member.

Description

Technical Field

[0001] The present invention relates to an industrial vehicle.

Background Art

[0002] As a conventional technique for industrial vehicles, for example, a rear axle support structure for a forklift disclosed in Patent Document 1 is known. In the rear axle support structure for a forklift disclosed in Patent Document 1, fixed shafts fixed to the front and rear of the rear axle that supports the left and right rear wheels at the rear of the vehicle body are supported by bearing portions fixed around the intermediate point between the left and right rear wheels so as to be rotatable in the left-right direction of the vehicle body. A resin spacer is inserted into the gap formed between the vertical surface of the fixed shaft and the vertical surface of the bearing portion.

[0003] Further, as another conventional technique, for example, an axle suspension device for an industrial vehicle disclosed in Patent Document 2 is known. In the axle suspension device for an industrial vehicle disclosed in Patent Document 2, an axle beam is rotatably supported between axle supports hanging down from a vehicle body frame via a cradle pin and a bearing portion. An elastic mount body formed of an elastic material is interposed between the vehicle body frame and the axle beam in a front-rear symmetrical posture. The elastic mount body includes a flat portion interposed in contact between the upper surface of the axle beam and the bottom surface of the vehicle body frame, a cylindrical portion fitted around the cradle pin and interposed between the cradle pin and the bearing portion, and a connecting portion disposed between the front and rear surfaces of the axle beam and the axle support to integrally connect the cylindrical portion and the flat portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of Invention

Problems to be Solved by the Invention

[0005] However, in the rear axle support structure for forklifts disclosed in Patent Document 1, although the resin spacer can reduce noise when the rear axle moves, a gap is created, so the movement of the rear axle cannot be suppressed. In addition, because the spacer is made of resin, there is a risk that the spacer will wear down significantly due to repeated forward and backward movement of the rear axle and repeated left and right rotation of the rear axle. As the wear of the spacer progresses, the amount of forward and backward movement of the rear axle increases, and the spacer becomes more susceptible to damage.

[0006] On the other hand, the elastic mount body for the axle suspension system of an industrial vehicle disclosed in Patent Document 2 has the problem of being structurally complex, lacking versatility, and being expensive to manufacture.

[0007] The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to provide an industrial vehicle that can absorb an axial gap between the center pin and the axle support that supports the axle using a simple elastic member to suppress the movement of the axle, and can also improve the reliability of the elastic member. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides an industrial vehicle having an axle equipped with a pair of left and right wheels, an axle support provided on the vehicle body and supporting the axle, a pair of front and rear center pins provided at the front and rear ends of the central part in the left-right direction of the axle, and a center pin support portion provided on the axle support and having an axle hole through which the center pins can be inserted, wherein the center pin has a shaft portion pivotally supported by the center pin support portion via a bush, a flange portion extending radially outward from the end of the shaft portion and fixed to the axle, and facing the end face of the center pin support portion in the front-rear direction, an elastic member interposed between the center pin support portion and the flange portion, and a grease supply passage that enables grease to be supplied from the outer circumferential surface of the bush to the elastic member.

[0009] In this invention, even if the axle support deflects, the elastic member deforms so as not to create an axial gap between the center pin support and the flange, thus virtually eliminating the risk of the axle beam moving in the axial direction. Furthermore, since a portion of the grease supplied to the bush is supplied to the elastic member through the grease supply passage, the lubrication of the elastic member by the grease is enhanced, improving the reliability of the elastic member.

[0010] Furthermore, in the industrial vehicle described above, the elastic member may be an O-ring surrounding the center pin, and may be configured to be interposed between the center pin support portion and the flange portion in a state of compression in the axial direction of the center pin. In this case, the elastic member is an O-ring surrounding the center pin. The elastic member is interposed between the center pin support portion and the flange portion in a state of compression in the axial direction of the center pin. Therefore, even if the center pin support portion bends and a gap is created between the center pin and the flange portion, the elastic member can deform to return to its original state and fill the gap.

[0011] Furthermore, in the industrial vehicle described above, the grease supply passage may be configured to have a grease passage formed in the center pin support portion, which allows grease to be supplied from the outer circumferential surface of the bush to the elastic member, and a groove on the outer circumferential surface of the bush, with one opening of the grease passage positioned opposite the groove. In this case, grease is more easily supplied from the grooves on the outer surface of the bush to the grease passage, ensuring that grease is reliably supplied to the elastic member.

[0012] Furthermore, in the industrial vehicle described above, the other opening of the grease passage may be configured to face the flange portion and be located radially closer to the center of the center pin than the elastic member. In this case, some of the grease that lubricates the bush is supplied from the outer surface of the bush through the grease passage to the radially central side of the center pin, beyond the elastic member. The grease supplied to the radially central side of the center pin is less likely to move radially outward due to the elastic member, thus preventing the grease from falling out.

[0013] Furthermore, in the industrial vehicle described above, the axle support has a support base portion connected to the vehicle body so as to extend in the longitudinal direction above the axle, the center pin support portion extends downward from the support base portion, and an annular groove for mounting the O-ring is formed in at least one of the flange portion and the center pin support portion, and the depth of the annular groove may be configured to decrease as it moves away from the support base portion. In this case, when the axle support flexes, a gap is created between the center pin support and the flange. At this time, the gap between the tip of the center pin support and the flange becomes larger than the gap between the base end of the center pin support near the support base and the flange. However, the depth of the annular groove decreases as it moves away from the support base. Therefore, the tip side of the O-ring that is part of the center pin support deforms in a direction that relieves the elastic deformation that was greatly compressed to match the size of the gap. Thus, the O-ring can fill the gap between the tip of the center pin support and the flange, which allows the axle to move in the axial direction. [Effects of the Invention]

[0014] According to the present invention, even if an axial gap occurs between the center pin and the axle support that supports the axle, it is possible to provide an industrial vehicle that can absorb the gap using a simple elastic member to suppress the movement of the axle, while also improving the reliability of the elastic member. [Brief explanation of the drawing]

[0015] [Figure 1] This is a side view of a forklift according to the first embodiment. [Figure 2] This is a rear view showing an overview of a forklift according to the first embodiment. [Figure 3] This is a view along line AA in Figure 2. [Figure 4] (a) is a perspective view of the main part of the forklift according to the first embodiment, and (b) is a perspective view of the bush. [Figure 5] This is an enlarged view showing the main parts of the forklift according to the first embodiment. [Figure 6] This is a cross-sectional view showing a state in which the axle support has deflected, causing the gap S1 to expand into a gap S2. [Figure 7] This is an enlarged view showing the main parts of the forklift according to the second embodiment. [Figure 8](a) is a diagram showing Modification 1, (b) is a diagram showing Modification 2, and (c) is a diagram showing Modification 3. [Mode for Carrying Out the Invention]

[0016] (First Embodiment) Hereinafter, a forklift as an industrial vehicle according to a first embodiment will be described with reference to the drawings. Note that "front-rear", "left-right", and "up-down" that specify directions are defined based on the state where the operator of the forklift is seated on the driver's seat in the driving position and faces the forward side of the forklift.

[0017] As shown in Figure 1, a forklift 10 as an industrial vehicle is provided with a cargo handling device 12 at the front portion of a vehicle body 11. A driver's seat 13 is provided near the center of the vehicle body 11, and an engine 14 is accommodated below the driver's seat 13 in the vehicle body 11. The forklift of the present embodiment is an engine-driven forklift that uses the engine 14 as a travel drive source.

[0018] The driver's seat 13 in the vehicle body 11 is provided with a driver's seat 15 on which an operator can sit. A steering wheel 16 is provided at the front portion of the driver's seat 13. The steering wheel 16 is for steering rear wheels 22 to be described later. The cargo handling device 12 includes a mast 17, and a pair of left and right forks 19 are provided on the mast 17 via a lift bracket 18. A counterweight 20 is provided at the rear portion of the vehicle body 11.

[0019] Front wheels 21, which are drive wheels, are provided at the front portion of the vehicle body 11 via a front axle (not shown). The front axle is fixed to the vehicle body 11. The front axle is provided with a power transmission mechanism (not shown) that transmits the rotation of the output shaft of the engine 14 to the front wheels 21.

[0020] As shown in Figure 2, the rear of the vehicle body 11 is equipped with rear wheels 22, which are the steering wheels, via a rear axle 23. The rear axle 23, as an axle, is equipped with a base plate 24 that extends in the left-right direction. An upper plate 25 is provided on the upper part of the base plate 24, and a lower plate 26 is provided on the lower part of the base plate 24. The upper plate 25 and the lower plate 26 are fixed to the base plate 24 by welding. A connecting plate 27 is provided at the rear of the base plate 24, connecting the upper plate 25 and the lower plate 26. The longitudinal direction of the rear axle 23 coincides with the width direction. The area near the left-right center of the base plate 24 and the connecting plate 27 correspond to the central part of the rear axle.

[0021] As shown in Figure 3, the center of the substrate 24 in the width direction is provided with a front center pin 28 that protrudes forward. The front center pin 28 has a shaft portion 29 and a flange portion 30 that extends radially outward from the end of the shaft portion 29. The flange portion 30 is welded to the substrate 24. On the other hand, the center of the connecting plate 27 in the width direction is provided with a rear center pin 31 that protrudes backward. The rear center pin 31 has a shaft portion 32 that protrudes backward coaxially with the shaft portion 29 and a flange portion 33 that extends radially outward from the end of the shaft portion 32. The flange portion 33 is welded to the connecting plate 27.

[0022] The front center pin 28 and the rear center pin 31 are rotatably supported by an axle support 40 provided on the vehicle body 11, allowing the vehicle body 11 to tilt from side to side while the wheels are in contact with the ground. The axle support 40 will be described later. The front center pin 28 and the rear center pin 31 correspond to a pair of front and rear center pins. The axis P of the front center pin 28 and the axis Q of the rear center pin 31 extend in the front-rear direction and are substantially coaxial with each other.

[0023] As shown in Figure 2, the rear axle 23 houses a hydraulic cylinder 34 for steering. The hydraulic cylinder 34 is a double-acting hydraulic cylinder that operates by receiving hydraulic fluid from a hydraulic circuit (not shown). The cylinder body 35 of the hydraulic cylinder 34 is fixed to the base plate 24 by bolts (not shown) or the like. The inside of the cylinder body 35 is divided into two chambers by a piston (not shown). Rods 36, 36 are connected to the piston, extending to the left and right from the piston and protruding to the left and right from the cylinder body 35, respectively. The rods 36 are displaced in the left and right directions by the operation of the hydraulic cylinder 34. The tip of each rod 36 is pivotally attached to the inner end of a tie rod 37. The outer end of the tie rod 37 is rotatably connected to a steering knuckle 38.

[0024] Steering knuckles 38 are supported at the left and right ends of the rear axle 23 so as to be rotatable to the left and right. The steering knuckle 38 has a kingpin (not shown) pivotally supported so as to have its axis in the vertical direction, and a wheel spindle (not shown) that protrudes from the kingpin outward in the left and right directions from the vehicle body 11. The rear wheel 22 is rotatably supported on the wheel spindle.

[0025] Next, the axle support 40 will be described. The axle support 40 is provided at the rear of the vehicle body 11. As shown in Figure 4, the axle support 40 has a support base portion 41, a front center pin support portion 42, and a rear center pin support portion 43. The support base portion 41 is a plate member that protrudes toward the rear and forms part of the rear frame of the vehicle body 11. A stopper member 44 is attached to the lower surface of the support base portion 41. The stopper member 44 restricts excessive lateral tilting of the rear axle 23 relative to the vehicle body 11. The front center pin support portion 42 and the rear center pin support portion 43 correspond to center pin support portions.

[0026] The front center pin support portion 42 is a member that extends downward from the front of the support base portion 41. The front center pin support portion 42 comprises a support body 45 welded to the lower surface of the base end portion, which is the front of the support base portion 41, and a bracket 46 fixed to the support body 45 by bolts 47. The front center pin support portion 42 has an axial hole 48 formed therein that allows the front center pin 28 to be inserted. The axial hole 48 is formed by the support body 45 and the bracket 46.

[0027] A bolt hole (not shown) into which a bolt 47 can be screwed is formed on the lower surface of the support body 45. The bracket 46 has a through hole (not shown) for inserting a bolt that matches the position of the bolt hole in the support body 45. With the bracket 46 removed, the front center pin 28 with the bush 51 attached is aligned with the shaft hole 48 of the support body 45, and then the bracket 46 is fixed to the support body 45, thereby pivotally supporting the front center pin 28 on the front center pin support 42.

[0028] As shown in Figure 4(a), the bush 51 is a cylindrical member. The bush 51 is fitted onto the shaft portion 29. Grease enhances the sliding properties between the shaft portion 29 and the front center pin support portion 42. Annular grooves 52 are formed near both ends of the outer circumferential surface of the bush 51, and a straight groove 53 is formed connecting the annular grooves 52. The annular grooves 52 and groove 53 are formed to facilitate the spreading of grease across the outer circumferential surface.

[0029] The rear center pin support portion 43 is a member that extends downward from the rear of the support base portion 41. The rear center pin support portion 43 comprises a support body 55 welded to the lower surface of the tip portion, which is the rear of the support base portion 41, and a bracket 56 fixed to the support body 55 by bolts 47. The rear center pin support portion 43 has an axial hole 57 formed therein that allows the rear center pin 31 to be inserted. The axial hole 57 is formed by the support body 55 and the bracket 56. The center of the axial hole 57 is approximately the same as the center of the axial hole 48.

[0030] A bolt hole (not shown) is formed on the lower surface of the support body 55 into which a bolt 47 can be screwed. The bracket 56 has a through hole (not shown) for inserting a bolt, which is aligned with the position of the bolt hole in the support body 55. With the bracket 56 removed, the rear center pin 31 with the bush 51 attached is aligned with the shaft hole 57 of the support body 55, and then the bracket 56 is fixed to the support body 55, thereby pivotally supporting the rear center pin 31 on the rear center pin support 43. The support body 55 has a bolt hole 60 for fixing the counterweight 20. The bolt hole 60 is located above the shaft hole 57.

[0031] As shown in Figure 4(a), a retaining plate 61 for preventing the bush 51 from coming loose is fixed to the rear surface of the bracket 56 by welding so as to cross a portion of the shaft hole 57. A grease injection passage 62 is formed in the bracket 56, penetrating from the side of the bracket 56 to the shaft hole 57. A grease nipple 63 is attached to the opening of the grease injection passage 62 on the side of the bracket 56. Thus, the grease nipple 63 and the grease injection passage 62 allow grease to be supplied to the bush 51 from the outside. Although not shown, a grease injection passage is also formed in the bracket 46 of the front center pin support portion 42, and a grease nipple is attached to the opening of the grease injection passage.

[0032] In this embodiment, an O-ring 65, which serves as an annular elastic member, is interposed between the front surface of the rear center pin support portion 43 and the rear surface of the flange portion 33. The O-ring 65 has a circular cross-section and is made of hard rubber. The hard rubber is, for example, nitrile rubber (NBR), which has high oil resistance. An annular groove 66 is formed across the front surfaces of the support portion body 55 and the bracket 56, allowing the O-ring 65 to be installed. The annular groove 66 is formed to surround the shaft hole 57. When the O-ring 65 is installed in the annular groove 66, it is compressed in the front-rear direction and becomes elastically deformed. With the O-ring 65 installed, the axial gap between the support portion body 55 and the flange portion 33 is S1 (see Figure 3).

[0033] In this embodiment, as shown in Figure 5, a grease passage 68 is formed in the support body 55. The grease passage 68 has a radial hole drilled from the shaft hole 57 of the support body 55 toward the radially outward direction of the shaft hole 57, and an axial hole drilled from the surface of the support body 55 facing the flange portion 33, substantially parallel to the shaft hole 57. The radial hole and the axial hole of the grease passage 68 are in communication with each other. The grease passage 68 is a passage for supplying grease to the O-ring 65 to smooth the sliding of the bush 51. In other words, the grease passage 68 is formed in the rear center pin support portion 43, enabling grease to be supplied from the outer circumferential surface of the bush 51 to the elastic O-ring 65.

[0034] The opening on the shaft hole 57 side of the radial hole of the grease passage 68 is formed in a position opposite to the annular groove 52 on the outer circumferential surface of the bush 51. This makes it easier for grease to enter the grease passage 68. The grease passage 68 and the annular groove 52 correspond to the grease supply passage. The opening in the radial hole of the grease passage 68 opposite the flange portion 33 is formed radially on the rear center pin 31 side of the annular groove 66 in which the O-ring 65 is fitted. This makes it difficult for grease discharged from the grease passage 68 to move outside the O-ring 65, and prevents grease from falling off the support body 55.

[0035] Next, the operation of the forklift 10 of this embodiment will be described. The rear axle 23 is supported by the axle support 40. Specifically, the front center pin 28 of the rear axle 23 is pivotally supported by the front center pin support 42 via a bush 51, and the rear center pin 31 of the rear axle 23 is pivotally supported by the rear center pin support 43 via a bush 51. As a result, the vehicle body 11 can tilt in the left and right directions when the rear wheels 22 are in contact with the ground. The front center pin 28 is pivotally supported by the front center pin support 42 so as little gap as possible is created between the flange portion 30 and the support body 45. Similarly, the rear center pin 31 is pivotally supported by the rear center pin support 43 so as little gap as possible is created between the flange portion 33 and the support body 55, but the O-ring 65 fills the small gap S1 that remains.

[0036] The forklift 10 is equipped with a counterweight 20 at the rear of the vehicle body 11, and the axle support 40 flexes under the load of the counterweight 20. This flexing widens the gap between the rear center pin support 43 and the flange portion 33 of the rear center pin 31. For example, the gap S1 between the rear center pin support 43 and the flange portion 33 of the rear center pin 31, as shown in Figure 3, widens to a gap S2 as shown in Figure 6 due to the flexing. In this embodiment, even if the gap S1 widens to a gap S2 due to the flexing of the axle support 40, the O-ring 65, which is pre-compressed and installed, fills the deformed and widened gap S2, thereby suppressing axial movement of the rear axle 23.

[0037] Grease is spread over the bush 51, and frictional wear is suppressed by the grease. The grease is injected from the grease nipple 63 using a grease gun, passes through the grease injection passage 62, and spreads to the outer surface of the bush 51. The grease also spreads to the entire outer surface of the bush 51 through the annular groove 52 and groove 53. A portion of the grease on the outer surface of the bush 51 enters the grease passage 68 upon injection into the grease nipple and is discharged radially inward of the O-ring 65. The grease discharged from the grease passage 68 reduces friction and wear of the O-ring 65 and improves the reliability of the O-ring 65.

[0038] The forklift 10 according to this embodiment provides the following effects. (1) Even if the axle support 40 bends, the O-ring 65, acting as an elastic member, deforms to fill the axial gap between the rear center pin support 43 and the flange portion 33, so there is virtually no risk of the rear axle 23 moving in the axial direction. In addition, some of the grease supplied to the bush 51 is supplied to the O-ring 65 through the grease passage 68, which increases the lubrication of the O-ring 65 by the grease and improves the reliability of the O-ring 65.

[0039] (2) The elastic member is an O-ring 65 that surrounds the rear center pin 31. The O-ring 65 is interposed between the rear center pin support portion 43 and the flange portion 33 in a state of compression in the axial direction of the rear center pin 31. Therefore, even if the rear center pin support portion 43 bends and a gap is created between the rear center pin 31 and the flange portion 33, the O-ring 65 deforms to return to its original state and fill the gap. As a result, axial movement of the rear axle 23 can be suppressed.

[0040] (3) A portion of the grease that lubricates the bush 51 is supplied from the outer surface of the bush 51 through the grease passage 68 to the radially central side of the rear center pin 31 beyond the O-ring 65. The grease supplied to the radially central side of the rear center pin 31 is blocked by the O-ring 65 and has difficulty moving radially outward, thus preventing the grease from falling out.

[0041] (4) Since the opening of the grease passage 68 on the side of the shaft hole 57 is formed in a position opposite to the annular groove 52 on the outer surface of the bush 51, grease can easily enter the grease passage 68 from the annular groove 52. There is virtually no risk of insufficient grease for the O-ring 65.

[0042] (5) Even if the axle support 40 is deflected, the O-ring 65, acting as an elastic member, deforms to fill the axial gap between the rear center pin support 43 and the flange portion 33, thus eliminating the need for adjustment work to eliminate the gap using shims and reducing the burden on the worker. In addition, the damping function of the O-ring 65 prevents the generation of knocking noises even if the rear axle 23 moves in the axial direction.

[0043] (Second embodiment) Next, a forklift according to the second embodiment will be described. In this embodiment, the configuration of the annular groove into which the O-ring, as an elastic member, is fitted differs from that of the first embodiment. In this embodiment, the same configuration as in the first embodiment will be referred to in the description of the first embodiment, and the same reference numerals will be used.

[0044] In the forklift 70 shown in Figure 7, an annular groove 71 is formed across the front surfaces of the support body 55 and the bracket 56, allowing an O-ring 65 to be fitted. The annular groove 66 is formed to surround the shaft hole 57. When the O-ring 65 is fitted in the annular groove 71, it is compressed in the front-rear direction and becomes elastically deformed. With the O-ring 65 fitted, the axial gap between the support body 55 and the flange portion 33 is S1 (see Figure 3).

[0045] In this embodiment, the annular groove 71 is formed such that the groove depth decreases as it moves away from the support base portion 41 located at the top. As shown in Figure 7, at the highest position in the annular groove 71 closest to the support base portion 41, the groove depth is D1, which is the maximum. As you move downwards from the highest position in the annular groove 71, the groove depth gradually decreases. At the lowest position in the annular groove 71 furthest from the support base portion 41, the groove depth is D2, which is the minimum. Since the gap between the support body 55 and the flange portion 33 is S1, at groove depth D2, the O-ring 65 is compressed and elastically deformed to a greater extent compared to the elastic deformation at groove depth D1.

[0046] In this embodiment, the same effects as those of the first embodiment are achieved. Furthermore, in this embodiment, when the axle support 40 flexes, a gap is created between the rear center pin support portion 43 and the flange portion 33. At this time, the gap between the tip (lower end) of the rear center pin support portion 43 and the flange portion 33 is larger than the gap between the base end (upper end) of the rear center pin support portion 43 near the support base portion 41 and the flange portion 33. However, the depth of the annular groove 71 decreases as it moves away from the support base portion 41. Therefore, the tip side of the O-ring 65 over the rear center pin support portion 43 deforms in a direction that restores the elastic deformation that was greatly compressed to match the size of the gap. Thus, the O-ring 65 can fill the gap between the tip of the rear center pin support portion 43 and the flange portion 33, which allows the rear axle 23 to move in the axial direction.

[0047] (modified version) Next, we will describe modified examples 1 to 3. In modified example 1 shown in Figure 8(a), not only is the rear center pin support portion 43 provided with an annular groove 66, but an annular groove 81 opposite to the annular groove 66 is also formed on the rear surface of the flange portion 33. By fitting the O-ring 65 into the annular groove 66 of the rear center pin support portion 43 and the annular groove 81 of the rear center pin 31, the O-ring 65 becomes less likely to fall off.

[0048] Figure 8(b) shows Modification 2, an example in which two O-rings 65 are used. The rear center pin support portion 43 is provided with an annular groove 66 for the O-ring 65 to be mounted on the rear center pin support portion 43. On the other hand, an annular groove 82 for the O-ring 65 to be mounted on the rear center pin 31 is formed on the rear surface of the flange portion 33. The annular groove 82 faces the annular groove 66 in the axial direction. Therefore, the two O-rings 65, which have been pre-compressed and elastically deformed in the axial direction, overlap. By using two O-rings 65, the gap between the tip of the rear center pin support portion 43 and the flange portion 33, which allows the rear axle 23 to move in the axial direction, can be filled.

[0049] In the modified example 3 shown in Figure 8(c), the opening of the grease passage 83 on the flange portion 33 side is located radially outside the annular groove 66. Even with the grease passage 83 of modified example 3, it is possible to supply grease to the O-ring 65.

[0050] It should be noted that the present invention is not limited to the above embodiments (including modified examples), and various modifications are possible within the scope of the spirit of the invention. For example, it may be modified as follows.

[0051] ○ In the above embodiments (including modifications), an O-ring was used as an example to describe the elastic member, but it is not limited to this. The elastic member can be any member that is elastically deformable and can fill the gap between the tip of the center pin support portion that allows the axle to move in the axial direction and the flange portion of the center pin. Furthermore, when the elastic member is an O-ring, there are no particular restrictions on the cross-sectional shape of the O-ring, and it may be a polygon such as a square, for example. ○ In the above embodiments (including modifications), the bush is provided with a pair of annular grooves and grooves connecting the annular grooves on its outer circumferential surface, but it is not limited thereto. For example, the bush may have only one annular groove on its outer circumferential surface. Alternatively, it may be a bush without an annular groove, provided with a through hole that penetrates from the outer circumferential surface to the inner circumferential surface. ○ In the above embodiments (including modifications), a rear axle mounted on the rear of the vehicle body was used as an example, but the axle is not limited to this. The axle may be, for example, a front axle mounted on the front of the vehicle body. ○ In the above embodiments (including modifications), a forklift was used as an example of an industrial vehicle, but it is not limited to this. The industrial vehicle may be, for example, a towing tractor, a towing vehicle, or an automated guided vehicle. [Explanation of Symbols]

[0052] 10, 70 forklifts 11 Car body 12. Cargo handling equipment 13. Driver's seat 15. Driver's seat 17 Mast 19 Forks 20 counterweights 21 Front Wheel 22 Rear wheels 23 Rear axle (axle) 28 Front center pin (center pin) 29, 32 Shaft section 30, 32 Flange section 31 Rear center pin (center pin) 34 Hydraulic Cylinder 40 Axle Supports 41 Support base 42 Front center pin support section 43 Rear center pin support section 51 Bush 52 Ring groove 53 Groove 65 O-ring (elastic component) 66 Annular groove 68 Grease passage 71, 81, 82, 83 Annular groove P, Q axis center

Claims

1. an axle equipped with a pair of wheels on the left and right, An axle support provided on the vehicle body and supporting the axle, A pair of front and rear center pins are provided at the front and rear ends of the central part of the axle in the left-right direction, In an industrial vehicle having a center pin support portion provided on the axle support and having an axle hole that allows the insertion of the center pin, The aforementioned center pin is A shaft portion that is pivotally supported by the center pin support portion via a bushing, It has a flange portion that extends radially outward from the end of the shaft portion and is fixed to the axle, and that faces the end face in the front-rear direction of the center pin support portion, An elastic member interposed between the center pin support portion and the flange portion, An industrial vehicle characterized by having a grease supply passage that enables grease lubrication from the outer circumferential surface of the bush to the elastic member.

2. The industrial vehicle according to claim 1, characterized in that the elastic member is an O-ring surrounding the center pin, and is interposed between the center pin support portion and the flange portion in a state of being compressed in the axial direction of the center pin.

3. The grease supply passage is, A grease passage is formed in the center pin support portion, which allows grease to be supplied from the outer surface of the bush to the elastic member, The bush has grooves on its outer circumferential surface, The industrial vehicle according to claim 1 or 2, characterized in that one opening of the grease passage is provided at a position opposite to the groove.

4. The industrial vehicle according to claim 3, characterized in that the other opening of the grease passage faces the flange portion and is located radially closer to the center of the center pin than the elastic member.

5. The axle support has a support base portion that is connected to the vehicle body so as to extend in the front-rear direction above the axle, The center pin support portion extends downward from the support base portion, An annular groove for mounting the O-ring is formed in at least one of the flange portion and the center pin support portion. The industrial vehicle according to claim 2, characterized in that the depth of the annular groove decreases as it moves away from the support base portion.

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