JP3155654B2 - Work machine connection structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting structure of a working machine in which a bracket and a boss are connected by pins, such as a connecting structure of a boom and an arm of a hydraulic shovel.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view showing a connecting structure of a conventional working machine of this kind, for example, a hydraulic shovel. The conventional connection structure shown in FIG. 2 includes, for example, a cylindrical pin 3 for connecting a bracket 1 forming an arm end, a boss 2 forming a boom end, and a connection between the bracket 1 and the boss 2. Sealing means provided in the gap 4 between the opposing end faces to prevent foreign matter such as mud entering from the outside, for example, O-
A ring 5, a pair of bushes 7 fitted in holes 6 formed in the boss 2 and holding the pins 3 so as to be relatively rotatable, and a dust seal 8 mounted outside the ends of these bushes 7. And a shim 9 inserted into the gap 4 described above. At one end of the pin 3 (on the right side in FIG. 2) and the bracket 1, a through hole 10 into which a rotation preventing bolt (not shown) is inserted is provided, and at the other end of the pin 3, a greasing hole 3 a is provided.
Is provided.

[0003] In such a connection structure of a hydraulic excavator,
Since the boss 2 is relatively rotated around the pin 3 as the pin 3 relatively slides on the inner peripheral surface of the bush 7, the boss 2 is rotated from the other end of the pin 3 (the left side in FIG. 2). Lubricating oil such as grease is supplied to the sliding portion of the pin 3 and the bush 7 through the greasing hole 3a, thereby preventing the pin 3 and the bush 7 from being worn or damaged. Further, by attaching an O-ring 5 to the outer periphery of the gap 4 between the opposed end faces of the bracket 1 and the boss 2, foreign matter such as mud is prevented from entering the gap 4 and the dust seal inside the gap 4 is prevented. 8 prevents foreign matter from entering the sliding portions of the pin 3 and the bush 7. By inserting a shim 9 having a predetermined thickness into the gap 4, relative movement of the pin 11 between the bracket 1 and the boss 2 in the axial direction is prevented.

[0004]

In the prior art described above, the load acting in the circumferential direction of the pin 3, for example, in the vertical direction in FIG. No structural consideration is given to the load acting in the direction, that is, the lateral direction in FIG. For this reason,
When an excessively large load is suddenly applied in the axial direction of the pin 3 during the excavation operation performed by the excavator, the end face of the boss 2 is significantly deformed so that normal excavation operation becomes difficult,
Abnormal wear of the end face of the boss 2 causes an axial relative movement between the bracket 1 and the boss 2, that is, a so-called play, which reduces workability and simultaneously generates noise. Was.

In addition, since it is necessary to supply oil from the other end of the pin 3 through the oil supply hole 3a, the operation of supplying oil is complicated and the running cost is increased.
Particularly, in the case of a hydraulic excavator, since there are as many as 10 or more greasing points per unit, the above greasing work is more complicated. Recently, hydraulic excavators are used for road construction, landscaping, and agricultural work in urban areas, causing a large amount of grease adhering to sliding parts of pins and bushes to fall and contaminate the ground. Therefore, there is a demand for non-greasing of the above-mentioned sliding portion.

Further, when the bush 7 is worn,
Maintenance is required to remove the corresponding bush fitted to the boss 2 and insert a new bush into the boss 2 to fit the boss 2. However, since maintenance of the bush is not easy, this maintenance is very difficult. Was troublesome.

The present invention has been made in view of such a situation in the prior art, and has as its object to eliminate the need for lubrication of sliding portions of pins and bushes, and to prevent deformation and abnormal wear of the end faces of bosses. It is an object of the present invention to provide a connection structure of a working machine that can perform the connection.

[0008]

SUMMARY OF THE INVENTION In order to achieve this object, the present invention relates to a pin for connecting a bracket and a boss so as to be relatively rotatable and integrally fixed to the bracket, and a bracket and a boss. And a bush mounted inside the boss and holding the pin so as to be relatively rotatable. In the coupling structure, a first bush in which the bush is fitted inside the boss, and a second bush disposed between the first bush and the pin and movable in a direction along the axial direction of the pin. The first bush and the second bush each have a tapered portion that can abut against each other, and the locking portion that restricts the movement of the second bush at the pin portion. At least a second bush of the first bush and the second bush of the bush is made of a non-greasing material, and the second bush is urged in a direction along the axial direction of the pin. It has a configuration provided with force means.

[0009]

According to the present invention, as described above, since the second bush disposed between the first bush mounted inside the boss and the pin is made of a non-lubricating material, external lubrication is required. The wear of the sliding portion of the pin and the bush can be suppressed without the need.

Further, the first bush and the second bush have a tapered portion which can abut against each other, the first bush is fitted to the boss and locked immovably, and the second bush is fixed. Although it is movable in the axial direction of the pin, its movement is locked by locking to the locking portion of the pin. Since the pin is provided integrally with the bracket, the first bush and the second bush are provided. Although relative rotation between the pins is allowed, movement of the pins in the axial direction is basically restricted. Therefore, even when an excessively large load is suddenly applied in the axial direction of the pin, basically there is no relative movement in the axial direction of the pin between the bracket and the boss, and the gap between the end face of the bracket and the boss is reduced. Can be kept constant.

If the tapered portion of each of the first bush and the second bush is worn due to the relative rotation between the pin and the bush repeated for a long period of time, the tapered portion caused by the wear is provided. Only the second bush can be moved in the direction along the axial direction of the pin by the urging means so that the gap between the portions is eliminated,
Thus, the gap between the opposed end faces of the bracket and the boss can be kept constant.

Thus, it is possible to prevent backlash between the end faces of the bracket and the boss.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of a connection structure of a working machine according to the present invention. FIG. 1 is a sectional view showing one embodiment of a connection structure of a working machine according to the present invention. This embodiment is also applied to a hydraulic excavator, for example. In FIG. 1, the same components as those shown in FIG. 2 described above are denoted by the same reference numerals. That is, 1 is a bracket forming an arm end, 2 is a boss forming a boom end, 4 is a gap formed between an end face of the bracket 1 and an end face of the boss 2, and 5 is a gap 4. An O-ring, 6 is a hole formed inside the boss 2, and 8 is a dust seal.

In this embodiment, in particular, as shown in FIG. 1, a flanged cylindrical pin 11 for connecting the bracket 1 and the boss 2 is opposed to the inside of the boss 2 with a predetermined gap therebetween. A pair of bushings 12, 1
3 and an automatic biasing means 14 for automatically keeping the size of the gap 4 between the opposed end faces of the bracket 1 and the boss 2 constant.
And

The above-mentioned pin 11 is integrally provided on the bracket 1 by a locking bolt (not shown) inserted into a flange portion 15 and a through hole 16 penetrating the bracket 1. The above-mentioned through hole 16 is formed in a long hole shape in consideration of the fact that the pin 11 may move in the circumferential direction and may be difficult to attach when the pin 11 is attached.

The above-described bush 12 is fitted into the hole 6 of the boss 2 and is locked immovably with a first bush 17.
Inserted between the first bush 17 and the pin 11,
A second bush that is movable in a direction along the axial direction of the pin 11, and is restricted from moving by being locked by a locking portion of the pin 11, that is, a bush retainer 21 described later mounted on the pin 11. 18 and has a two-layer structure. On the inner peripheral side of the first bush 17, a tapered portion 17a whose inner diameter gradually increases toward the end is provided.
The outer peripheral side of the second bush 18 has the above-described tapered portion 17.
and a taper portion 18a that comes into contact with a. These bushes 17 and 18 have, for example, different wear coefficients, the second bush 18 is made of a non-greasing material such as an oil-containing bush, and the first bush 17 is made of a material made of iron.

The other bush 13 has the same structure as the bush 12, and is fitted into the hole 6 of the boss 2 and is locked immovably. It is inserted between the pin 11 and is movable in a direction along the axial direction of the pin 11, and the movement is restricted by being locked by a locking portion of the pin 11, that is, a collar 15 of the pin 11. The second bush 20 has a two-layer structure. Further, the inner peripheral side of the first bush 19 has a tapered portion 1 whose inner diameter gradually increases toward the end.
9a is provided on the outer peripheral side of the second bush 20.
A tapered portion 20a that contacts the above-described tapered portion 19a is provided. These bushes 19 and 20 also have different wear coefficients, for example, and the second bush 20 is made of a non-lubricating material such as an oil-impregnated bush.
Is made of iron material.

The above-mentioned automatic urging means 14 is provided at one end of the pin 11 (the side opposite to the flange 15). The automatic biasing means 14 is inserted into the hole 1 a formed in the bracket 1, and has a cylindrical bush retainer 21 to which one end of the second bush 18 is engaged as described above, and is attached to one end of the bush retainer 21. The plate body 22 to be inserted and the plate body 22
It comprises a pair of bolts 23 screwed to one end of the pin 12 and an elastic body 24 such as a spring interposed between the head of the bolt 23 and the plate 22.

In this embodiment, a part of the bushes 12, 13 mounted inside the boss 2, that is, the second bushes 18, 20 are made of a non-greasing material.
Wear of the sliding portions of the pin 11 and the bushes 12, 13 is suppressed without requiring external greasing. Therefore, running costs associated with lubrication can be reduced.

In this embodiment, since the bushing presser 21 is pressed rightward in FIG. 1 via the plate 22 by the elastic force of the elastic body 24, the second bush 18 also moves rightward in FIG. When pressed, the taper portions 17a and 18a are urged to abut each other. At the same time, the second bush 20 comes into contact with the flange 15 of the pin 11, and the first bush 17,
Since the boss 19 is fitted to the boss 2, that is, provided integrally, the taper portions 19 a and 20 a on the bush 13 side are urged by the above-described urging force so as to abut each other. As a result, the boss 2 is pressed by the pair of second bushes 18 and 20 via the first bushes 17 and 19.
Therefore, for example, even when an excessively large load is suddenly applied in the axial direction of the pin 11 during excavation work performed by the hydraulic excavator, the contact between the first bush 17 and the second bush 18, and The relative movement of the pin 11 between the bracket 1 and the boss 2 in the axial direction does not basically occur due to the contact between the first bush 19 and the second bush 20, and between the end faces of the bracket 1 and the boss 2. The gap size can be kept constant.

Also, suppose that the pins 11 and the bushes 12, 13
Between the tapered portion 17a of the first bush 17 and the tapered portion 18a of the second bush 18, or the tapered portion of the first bush 19 with the relative rotation repeated for a long time between When the wear occurs between the tapered portion 19a and the tapered portion 20a of the second bush 20 and a gap due to the wear is generated in the tapered portion, the plate 22 and the bush retainer 21 are moved by the elastic force of the elastic body 24. Through the second bush 1 in a direction along the axial direction of the pin 11.
8 or the second bush 20 is moved, and thereby, between the taper portions 17a and 18a or the taper portion 19a.
A gap is not formed between the brackets 1 and 20a, and accordingly, the gap between the mutually facing end faces of the bracket 1 and the boss 2 is automatically kept constant.

As described above, when an excessively large load is suddenly applied in the axial direction of the pin 11, play occurs between the end faces of the bracket 1 and the boss 2, or the taper 17 a, The occurrence of backlash due to wear occurring between 18a and between the tapered portions 19a and 20a can be prevented, so that the end face of the boss 2 can be prevented from being deformed or abnormally worn, and the relative rotation between the bracket 1 and the boss 2 can be prevented. The operation, that is, the relative rotation operation between the arm and the bracket (not shown) can always be satisfactorily performed, so that workability can be improved, and at the same time, generation of noise can be suppressed.

When the tapered portions 17a to 20a are considerably worn, the bolts 23 are appropriately tightened to form the tapered portions 17a and 18a and the tapered portions 19a and 20a.
a The contact force between the members can be adjusted. Also, the tapered portion 17a
When the degree of wear of the second bushing 18 to 20a becomes significant and the elastic force of the elastic body 24 cannot be obtained any more,
Only 0 needs to be exchanged. At this time, the second bush 1
8 and 20 are movable, that is, neither the pin 11 nor the first bushes 17 and 19 are fitted.
It can be easily attached and detached, and excellent maintainability can be secured.

In the above embodiment, the first bush 1
Although 7 and 19 are made of iron, they may be made of a non-greasing material as in the case of the second bushes 18 and 20.

In the above description, the automatic biasing means 14 having the elastic body 24 is provided.
It is also possible to adopt a configuration in which the second bushes 18 and 20 are urged simply by a manual bolting operation.

[0026]

Since the present invention is constructed as described above, it is possible to eliminate the need for lubrication at the sliding portions of the pins and bushes, without the need for external greasing, and to reduce the running cost as compared with the prior art. Can be reduced.

Further, since deformation and abnormal wear of the end face of the boss can be prevented, relative rotation between the bracket and the boss can always be performed favorably, thereby improving workability as compared with the prior art. Can be improved, and at the same time, generation of noise can be suppressed.

Further, since the second bush can be easily attached and detached, maintenance can be performed more easily than in the prior art.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a connection structure of a working machine according to the present invention.

FIG. 2 is a cross-sectional view showing a connection structure of a conventional working machine.

[Explanation of symbols]

 Reference Signs List 1 bracket 2 boss 4 gap 5 O-ring (seal means) 11 pin 12, 13 bush 14 automatic biasing means 17a to 20a taper portion 17, 19 first bush 18, 20 second bush 21 bush retainer 22 plate 23 bolt 24 elastic body

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E02F 9/00 E02F 3/38 E02F 3/40

Claims (3)

(57) [Claims] 1. A bracket and a boss are rotatably connected to each other and arranged between a pin fixed integrally to the bracket and opposed end faces of the bracket and the boss, and enter from the outside. In a coupling structure for a working machine, comprising a sealing means for preventing foreign matter and a bush mounted inside the boss and holding the pin so as to be relatively rotatable, the bush is fitted inside the boss. A first bush, and a second bush disposed between the first bush and the pin, the second bush being movable in a direction along the axial direction of the pin. A first bush and a second bush of the bush are provided with a taper portion capable of abutting each other on each of the bushes; and a locking portion for restricting movement of the second bush at the pin portion. At least a second bush of the bush is made of a non-lubricating material, and is provided with an urging means for urging the second bush in a direction along an axial direction of the pin. Connection structure. 2. The connecting structure for a working machine according to claim 1, wherein the first bush and the second bush have different wear coefficients. 3. The working machine according to claim 1, wherein said urging means is an automatic urging means for automatically urging said second bush by an elastic force of an elastic body. Connection structure.