JPH0575079U - Tracked tractor suspension - Google Patents

Abstract

(57) [Summary] [Purpose] The equalizer bar type suspension system for bulldozers
When the equalizer bar swings, the track frame toe-in,
Try not to toe out. [Structure] A joint shaft 20 having a spherical surface portion 21 and a taper portion 22 is attached to an end portion of an equalizer bar 10 via a spherical bearing 11. The spherical surface portion 21 is pivotally attached to one boss 3 fixed to the track frame 1 via a spherical bush 12 and the bush 5 having a square hole 6 larger than the tapered portion 22 is press-fitted into the other boss 4 to form a square hole 6 The taper portion 22 is loosely fitted in. In the vehicle body standard state, the taper portion 22 is in contact with the side of the square hole 6 on the track frame 1 side, and there is a gap 23 between the opposite side and the upper side. When the equalizer bar oscillates, the joint shaft 20 oscillates about the spherical surface portion 21, and the taper portion 22 forms the square hole 6.
It slides on the bottom surface of the plate with a small force and moves to the opposite side of the track frame 1. Therefore, track frame 1
Does not toe in or toe out.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a suspension system for a track-type tractor that connects a vehicle body and a track frame.

[0002]

[Prior Art]

 As shown in FIG. 5, a suspension system for a track-type tractor includes a pivot shaft 31 fixed to a vehicle body 30 on which a track frame 1 is swingably mounted, and a lower wheel 35 mounted on the track frame 1. The guide wheel 36 guides the crawler belt 34. The starting wheel 33 is fixed to the starting wheel shaft 32 arranged at a position different from the pivot shaft 31, and transmits power to the crawler belt 34.

As shown in FIG. 6 which is a view from the arrow G in FIG. 5, the equalizer bar 10 is pivotally attached to the vehicle body 30 by a center pin 38, and both ends thereof are attached to the track frame 1 by pins 37. Has been done. When the track frame 1 receives an external force from the lateral direction, the tip of the track frame 1 (the left side in the figure) is moved toward the center of the vehicle around the point N in FIG. , The equalizer bar 10 connects the left and right track frames 1 and the vehicle body 30 with a pin 37 to prevent the track frame from toe-in and toe-out by external force.

When the tractor travels on rough terrain, the truck frame 1 swings up and down along the terrain around the pivot shaft 31 as shown in FIG. 5, so that the body 30 is less swayed.

However, in the above-described suspension device, as shown in FIG. 6, the pin 37 connected to the track frame 1 of the equalizer bar 10 moves on an arc of radius R centered on the center pin 38 and moves to the pin 37. When is displaced by x, the pin 37 is displaced toward the inside of the vehicle body by δ _{1 from the} initial position.

When viewed from the H direction in FIG. 5, the center line K-K of the track frame 1 is δ ₁ on the center line of the equalizer bar 10 with the center N of the pivot shaft 31 as the center, as shown in FIG. The position is shifted by K ₁ -K ₁ , and when the crawler belt 34 is wound around the starting wheel 33, the center of the crawler belt 34 and the center of the starting wheel 33 are shifted by δ ₂ .

In other words, the toe-in causes misalignment, and uneven wear occurs on the tooth side of the starting wheel 33, the side surface of the crawler belt link, the collar of the lower rolling wheel 35, the bush of the crawler belt 34, etc., and the life is shortened. However, there is a problem in that excessive load is applied to the track frame and the pivot shaft at a high frequency and the life is shortened.

Further, when earthmoving work is performed with a bulldozer, as shown in FIG. 8, when the load applied to the earthwork plate 40 is light, the crawler belt 34 has the entire ground contact surface in contact with the ground. When the earthwork plate 40 is pushed down by the hydraulic cylinder 41 and the load is increased, the vehicle body 30 receives the reaction force and rises, the guide wheel 36 also rises, and the contact length of the crawler belt 34 is shortened, and slippage with the ground occurs. Raising it reduces the driving force.

The operator detects a slight lifting of the vehicle body to reduce the load on the earthwork plate and controls so that the crawler belt does not slip. Therefore, it is necessary for the connecting portion between the vehicle body and the truck frame to have appropriate play in the vertical direction.

In order to solve the above problems, Japanese Utility Model Laid-Open No. 3-109986 as shown in FIG. 10 has been proposed. FIG. 10 is a cross-sectional view of the connecting portion between the equalizer bar and the track frame, and the spherical bearing 11 attached to the equalizer bar 10 is equipped with a joint shaft 60.

A spherical portion 61 at one end of the joint shaft 60 is pivotally attached to one boss 51 of the bracket 50 welded to the track frame 1 via a spherical bush 52. The cylindrical portion 62 at the other end of the joint shaft 60 is loosely fitted in a tapered hole 54 provided in the other boss 53 of the bracket 50 and having a diameter larger than that of the cylindrical portion 62.

In the standard state of the vehicle body, the cylindrical portion 62 of the joint shaft 60 is in contact with the track frame 1 side of the tapered hole 54 of the boss 53, as shown in FIG. 11 showing the ZZ cross section of FIG. There is a gap 63 on the opposite side.

When the equalizer bar 10 swings and the center of the joint shaft 60 moves up and down by x as shown in FIG. 12, the center of the joint shaft 60, that is, the center of the spherical bearing 11 shifts by δ ₁ . The joint shaft 60 swings around the spherical surface portion 61, and the cylindrical portion 62 abuts on the opposite side of the taper hole 54 from the track frame 1 as shown in FIG. 13, so that a gap 63 exists on the track frame side. ..

Therefore, the bending force on the track frame 1 is reduced, and even when a load is applied to the earthwork plate, there is a gap in the upward direction, so that the operator can deal with the slip.

[0015]

[Problems to be solved by the device]

 However, according to the above configuration, the cylindrical portion of the joint shaft is inserted into the taper hole having a large diameter and is loosely fitted. Therefore, as shown in FIG. The center B of the cylindrical portion 62 (two-dot chain line) in (1) moves to the center line C-C of the tapered hole 54 (solid line), and the track frame 1 is toe out by a.

When the equalizer bar 10 swings, the center of the joint shaft 60 shifts by δ ₁ as shown in FIG. 12, and the cylindrical portion 62 moves from the position indicated by the two-dot chain line in FIG. 15 to the position indicated by the dotted line b. However, the center portion B of the cylindrical portion 62 rises to the position of B ₁ while receiving the load W as described above. A force larger than the frictional resistance force μW between the cylindrical portion 62 and the tapered hole 54 in the L 2 direction is required. Therefore, the cylindrical portion 62 does not move to the point B ₁ and the track frame 1 is displaced in the L direction and toes in.

The present invention has been made in view of the above-mentioned problems, and an appropriate play can be vertically provided at the connecting portion between the equalizer bar and the track frame without toe-in and toe-out even when the equalizer bar swings. It is an object of the present invention to provide a suspension system of a tracked tractor having the same.

[0018]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, in the suspension system for a track-type tractor according to the present invention, one end of the suspension system for a track-type tractor that is swingably attached to a vehicle body and has an equalizer bar that connects both ends to a track frame is used. A joint shaft having a spherical portion on the other end and a taper portion on the other end is mounted on both ends of the equalizer bar via spherical bearings, and the spherical surface of the joint shaft is attached to one of a pair of bosses fixed to the track frame. It is characterized in that the taper portion of the joint shaft is pivotally attached, and the other boss is provided with a square hole larger than the tapered portion of the joint shaft so that the taper portion of the joint shaft is loosely fitted.

[0019]

[Action]

 According to the above configuration, the spherical surface portion of one end of the joint shaft swingably mounted on the equalizer bar is pivotally attached to the boss of the track frame, and the tapered portion of the other end is larger than the tapered portion provided on the boss. Since it fits loosely in the hole, the taper can slide on the flat surface of the square hole with a small force, and the equalizer bar secures both left-right escape and vertical play without great resistance to the track frame. it can.

[0020]

【Example】

 An embodiment of a suspension system for a track-type tractor according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a plan cross-sectional view of the joint portion between the equalizer bar and the track frame. The equalizer bar 10 has a spherical portion 21 at one end and a joint shaft 20 having a tapered portion 22 at the other end, and a spherical bearing. It is mounted so that it can swing freely via 11.

The spherical portion 21 of the joint shaft 20 is pivotally attached to one boss 3 of the bracket 2 welded to the track frame 1 via a spherical bush 12 and the lid 13 is fastened with a bolt 14. A bush 5 having a square hole 6 larger than the tapered portion 22 of the joint shaft 20 is press-fitted and fixed to the other boss 4 of the bracket 2, and the tapered portion 22 is loosely fitted in the square hole 6.

FIG. 2 is a sectional view taken along the line XX of FIG. 1. In the standard state, the tapered portion 22 is in contact with the lower side of the square hole 6 on the track frame side as shown in FIG. There is a gap 23 on the side. The degree of taper of the taper portion is determined so that the taper portion 22 makes line contact with the square hole 6.

When the equalizer bar 10 swings, the joint shaft 20 moves by δ ₁ as shown in FIG. As shown in FIG. 3, the joint shaft 20 swings around the spherical surface portion 21, and the taper portion 22 abuts on the lower side of the square hole 6 opposite to the track frame as shown in FIG. A gap 23 is formed in this.

In this case, the force in the L direction required for the paper portion 22 to move laterally is such that the taper portion 22 horizontally moves on the bottom surface of the square hole 6 and therefore the load W and the friction coefficient applied to the taper portion 22. The product of μ is μW, and the force in the L direction is small. Therefore, the track frame 1 does not move in the L direction, and the track frame 1 does not toe in.

Further, as shown in FIG. 2, an upward gap 24 is provided between the tapered portion 22 and the square hole 6 so that when the earthwork plate of the bulldozer is loaded, the operator does not slip It can cope with the occurrence sufficiently.

[0026]

[Effect of the device]

 As described in detail above, the present invention relates to an equalizer bar-type track-type tractor suspension device having both ends connected to a track frame, and a joint shaft having a spherical portion at one end and a taper portion at the other end at both ends of the equalizer bar. Via a spherical bearing, the spherical part of the joint shaft is pivotally attached to one of a pair of bosses fixed to the track frame, and the tapered part is inserted into a square hole larger than the tapered part provided on the other boss. Since it is fitted, the taper part can slide in the square hole with a small force, and the track frame does not toe in and out when the equalizer bar swings. Further, since the clearance is provided in the upward direction, the crawler type tractor suspension device can be obtained in which the operator can easily deal with slips during earthwork work of the bulldozer.

[Brief description of drawings]

FIG. 1 is a plan sectional view of a joint portion of the present invention in a standard state.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a plan sectional view of the joint portion of the present invention when the equalizer bar is swung.

4 is a cross-sectional view taken along line YY of FIG.

FIG. 5 is a side view of a crawler type tractor.

FIG. 6 is a front view of the suspension device viewed from G in FIG. 5;

FIG. 7 is a plan view of the underbody device seen from H in FIG. 5;

FIG. 8 is a state diagram of the bulldozer during light load work.

FIG. 9 is a state diagram of the bulldozer during heavy load work.

FIG. 10 is a plan sectional view of a conventional joint portion.

11 is a sectional view taken along line ZZ of FIG.

FIG. 12 is an explanatory diagram when the equalizer bar swings.

13 is a ZZ cross-sectional view of FIG. 10 when the equalizer bar is swung.

FIG. 14 is an explanatory diagram of a standard state of a conventional joint shaft cylindrical portion.

FIG. 15 is an explanatory diagram of a state where the equalizer bar of the conventional joint shaft cylindrical portion is swung.

[Explanation of symbols]

 1 Track Frame 2 Bracket 3,4 Boss 5 Bushing 6 Square Hole 10 Equalizer Bar 11 Spherical Bearing 12 Spherical Bushing 20 Joint Shaft 21 Spherical Part 22 Tapered Part 23, 24 Gap

Claims (1)

[Scope of utility model registration request] 1. A suspension system for a track-type tractor, which is pivotally mounted on a vehicle body and has both ends connected to a track frame, and is a suspension device for a track-type tractor. A shaft is swingably attached to both ends of the equalizer bar via spherical bearings, and a spherical portion of the joint shaft is pivotally attached to one of a pair of bosses fixed to the track frame, and the joint shaft is attached to the other boss. A suspension device for a crawler belt-type tractor, characterized in that a square hole having a diameter larger than the diameter of the tapered portion is provided, and the tapered portion of the joint shaft is loosely fitted.