JP2543538B2 - Pin coupling device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pin coupling device used in a construction machine such as a hydraulic shovel, and particularly to a sliding surface between a bush and a connecting pin even when working in seawater or the like. The present invention relates to a pin coupling device that can be lubricated for a long time.

[Conventional technology]

FIGS. 4 and 5 show a pin coupling device according to the prior art, taking a hydraulic shovel as an example.

In the figure, 1 is a lower traveling body, 2 is an upper revolving body rotatably mounted on the lower traveling body 1, and a working unit 3 is provided in front of the upper revolving body 2. The working unit 3 is generally composed of a boom 4, an arm 5 and a bucket 6,
These are operated by a boom cylinder 7, an arm cylinder 8 and a bucket cylinder 9, respectively. Here, the boom 4, the arm 5, the bucket 6, the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9 and the like are connected by pin connecting devices 10, 10, ....

Next, a pin coupling device for coupling between the arm 5 and the bucket 6.
This will be explained using 10 as an example.

In FIG. 5, reference numeral 11 denotes a boss portion provided at the tip of the arm 5 as one member. Inside the boss portion 11, axially opposite sides are provided, and a fitting insertion hole 11A for a bush 12 to be described later is provided. Provided (however, only one is shown in FIG. 5). A large-diameter oil sump 11B is formed in the axially intermediate portion between the fitting insertion holes 11A so as to make the inner peripheral side of the boss portion 11 concave. A seal groove 11C is provided at the axially outer end of each of the fitting insertion holes 11A, and a dust seal 16 described later is mounted in the seal groove 11C. Reference numeral 12 is a cylindrical bush inserted into each of the insertion holes 11A, and a connecting pin 13 described later is slidably inserted into the bush 12.

Reference numeral 13 denotes a connecting pin that rotatably connects the boss portion 11 to a bracket 15 described later through the bush 12, and a large-diameter stop plate 14 is attached to the tip of the connecting pin 13 and Board 14
This prevents the connecting pin 13 from coming off. Reference numeral 15 is a bracket provided on a bucket 6 which is a counterpart member of the arm 5, and the two brackets 15 project from the main body of the bucket 6 at a predetermined interval in the width direction, and both ends of the boss portion 11 in the axial direction. It is disposed on the side with a predetermined gap S (however, only one is shown in FIG. 5). A pin hole 15A is bored in the bracket 15 in the axial direction, and the connecting pin 13 is fitted in the pin hole 15A. In addition, 1
6 is a dust seal mounted in the seal groove 11C, the dust seal 16 is in sliding contact with the outer peripheral surface of the connecting pin 13, rainwater and muddy water from the outside enters the sliding surface of the bush 12 and the connecting pin 13 It is designed to prevent

The hydraulic shovel pin coupling device 10 according to the prior art has the above-described configuration, and the oil reservoir 11B of the boss portion 11 is filled with lubricating oil such as grease.
The lubricating oil in the oil sump 11B is guided to the sliding surface of the bush 12 and the connecting pin 13, and an oil film is formed on this sliding surface to lubricate the sliding surface. .

[Problems to be solved by the invention]

However, in the above-mentioned conventional technique, the seal groove of the boss portion 11 is
Since only the dust seal 16 is provided in 11C, the bush 1
Although it is possible to prevent rainwater, muddy water, etc. from entering the sliding surface of 2 and the connecting pin 13 from the outside, surely prevent the lubricating oil in the oil sump 11B from leaking to the outside via the sliding surface. There is a drawback that you cannot do it. In particular, when the bucket 6 or the tip of the arm 5 is submerged in seawater or the like, for example, when excavating earth and sand or the like from the bottom of the sea and discharging the soil, the lubricating oil in the oil reservoir 11B passes through the sliding surface and the dust seal 16. May leak into seawater, for example, once every half day, the oil sump 11B
There is a drawback that lubricating oil such as grease must be re-injected into the inside. Further, there is a drawback that the leak of the lubricating oil contaminates seawater and the like.

The present invention has been made in view of the above-mentioned drawbacks of the prior art. The present invention uses a double lip type seal composed of an oil seal and a dust seal to prevent the lubricating oil in the oil sump from accidentally leaking to the outside. In addition, the sliding surface of the bush and the connecting pin can be lubricated for a long time even when working in seawater, and when the lubricating oil is injected into the oil sump, it must be checked whether this lubricating oil is sufficiently filled. The object is to provide a pin coupling device that allows the user to easily check whether or not it is.

[Means for solving problems]

The feature of the configuration adopted by the present invention to solve the above-mentioned problems is that an oil provided between the bush and the connecting pin is introduced to guide the lubricating oil in the oil sump to the sliding surface of the bush and the connecting pin. And a double lip type seal formed of an oil seal and a dust seal provided between the inner peripheral side of the boss portion and the outer peripheral surface of the connecting pin located on the outer side in the axial direction of the bush, and the oil seal of the double lip type seal. A dust discharge passage formed in the boss portion so as to communicate the oil passage with the outside via a side, and a relief valve provided in the dust discharge passage and opened when the pressure in the oil sump exceeds a predetermined pressure. Is equipped with.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those of the prior art shown in FIG. 4 and FIG.
The description will be omitted.

In the figure, reference numeral 21 denotes a boss portion provided at the tip of the arm 5 as one member. The boss portion 21 is formed in substantially the same manner as the boss portion 11 used in the prior art, and a bushing described later is provided on the inner peripheral side. Fitting holes 21A, 21A, oil sump 21B and seal groove for 22
21C and 21C are provided respectively. Also, the boss portion 21
In order to inject a lubricating oil such as grease into the oil sump 21B in the radial direction, a nipple 21E is provided through an injection hole 21D. 22 and 22 are bushes used in the present embodiment which are fitted and inserted in the respective fitting holes 21A, and 23 and 23 are oil passages for guiding the lubricating oil in the oil sump 21B to the sliding surfaces of the bush 22 and the connecting pin 13. The oil passages 23 are provided on the inner peripheral surface of the bush 22 over the entire axial length thereof.

Reference numerals 24 and 24 are double lip type seals mounted in the respective seal grooves 21C. The double lip type seals 24 are, as shown in FIG. 2, an oil seal 24A located axially inside and a dust seal located axially outside. 24B and each seal 24
It consists of a holding member 24C that stores A and 24B in each seal groove 21C, and the lip part of each seal 24A and 24B is the connecting pin 1
It is in sliding contact with the outer peripheral surface of 3. Here, the dust seal 2
In 4B, rainwater or muddy water from the outside is pushed through the gap S.
22 is prevented from entering the sliding surface of the connecting pin 13.
On the other hand, the oil seal 24A forms a back pressure chamber 24D between the oil seal 24A and the end face of the bush 22, and the inside of the back pressure chamber 24D communicates with the oil sump 21B via the oil passage 23. Then, the lip portion of the oil seal 24A is pressed against the outer peripheral surface of the connecting pin 13 by the pressure of the lubricating oil flowing into the back pressure chamber 24D from the oil sump 21B, and this lubricating oil is prevented from leaking to the outside. To prevent.
Further, a dust discharge hole 24E is provided on the base end side of the oil seal 24A so as to penetrate the holding member 24C.
Connects the back pressure chamber 24D to a dust discharge passage 25 described later.

25 and 25 are oil seals 24A of each double lip type seal 24
Is a dust discharge passage formed in the boss portion 21 so as to communicate the oil passages 23 with the outside through the side, and the dust discharge passages 25 are formed in the circumferential wall of the boss portion 21 in the radial direction and the axial direction by substantially L. It extends in the next shape, and its base end side communicates with the inside of the back pressure chamber 24D through the dust discharge hole 24E on the oil seal 24A side.
The tip end side of each dust discharge passage 25 is a dust discharge portion 25A, 25A having a relatively large diameter, and the tip end of each dust discharge portion 25A is located on the inner surface of each bracket 15 through each gap S. The bosses 21 are open at both axial end surfaces thereof so as to face them.

Reference numerals 26 and 26 denote relief valves installed in the dust discharge portion 25A of each dust discharge passage 25. The relief valves 26 are provided on the end face of the dust discharge portion 25A on the base end side, as shown in FIG. Valve seat 26A and the dust discharge passages that are seated on and away from the valve seat 26A.
Ball 26B that opens and closes 25A to the outside, and ball 26B
The spring 26C for constantly urging the valve 26 in the valve closing direction is composed of a plug 26D screwed to the inner circumference of the tip end side of each dust discharge part 25A in order to hold the spring 26C. A small diameter dust discharge hole 26E is formed in the direction. Then, each of the relief valves 26 injects a lubricating oil such as grease into the oil reservoir 21B, opens when the pressure in the oil reservoir 21B becomes a predetermined pressure or more, and closes when the pressure falls below a predetermined pressure. There is.

Next, the operation of the pin coupling device configured as described above will be described.

First, when injecting a lubricating oil such as grease into the oil sump 21B, the lubricating oil such as grease is injected into the oil sump 21B from the nipple 21E using, for example, a grease gun. The lubricating oil injected into the oil sump 21B is
It is guided to the sliding surface of each bush 22 and the connecting pin 13 through the oil passage 23, and an oil film is formed on this sliding surface, and at the same time, the oil seal 24A of each double lip type seal 24 and each bush 1
It flows into the back pressure chamber 24D between the second end face and the end face of the second end face, and its oil pressure presses the lip portion of the oil seal 24A against the outer peripheral face of the connecting pin 13. As a result, the oil seal 24A can reliably prevent the lubricating oil in the oil sump 21B from leaking outside along the outer peripheral surface of the connecting pin 13.

Next, when the back pressure chambers 24D are filled with the lubricating oil from the oil sump 21B, the lubricating oil is filled with the oil seals.
It flows out into each dust discharge passage 25 through the dust discharge hole 24E on the 24A side, and presses the ball 26B of each relief valve 26 located at the tip end side of each duct discharge passage 25 against the spring 26C.
Then, when the oil sump 21B becomes a predetermined pressure or more due to the injection of the lubricating oil, each relief valve 26 is caused by the pressure at this time.
The valve is opened, and a part of the lubricating oil is discharged from each dust discharge portion 25A through the dust discharge hole 26E of each plug 26D into each gap S between the boss portion 21 and each bracket 15. Gap S
The lubrication oil can be stored in the oil reservoir 21B
It is possible to easily confirm from outside whether or not the filling is sufficiently performed, and the injection work can be immediately terminated.

On the other hand, abrasion powder, air, etc. accumulated in the oil sump 21B, the sliding surfaces of the bushes 22 and the connecting pins 13, the back pressure chamber 24D, etc. are discharged from the duct discharge passages 25 to the relief valves by the lubricating oil injection work. It will be discharged to the outside through 26, and it is possible to prevent abrasion powder and the like from remaining on the oil sump 21B and the sliding surface,
The sliding surface and the like can be cleaned each time the injection work is performed.

Thus, according to the present embodiment, when injecting the lubricating oil such as grease, it is possible to easily confirm from the outside whether or not the lubricating oil is sufficiently filled in the oil sump 21B and the like. Oil seal 24A on the outer peripheral surface and dust discharge passage 25
It is possible to surely seal by means of the relief valve 26, and it is possible to surely prevent the lubricating oil from accidentally leaking to the outside. Therefore, even when the bucket 6 or the tip side of the arm 5 is submerged in water or seawater, it is possible to reliably prevent the lubricating oil from leaking into the water or seawater, and to connect it to each bush 22. The sliding surface of the pin 13 can be lubricated for a long time. In addition, it is possible to prevent contamination of foreign countries and water by the lubricating oil, and prevent intrusion of seawater etc. by the dust seal 24B.

In the above embodiment, the oil passage is provided on the inner peripheral surface of each bush 22.
Although the recess 23 is provided, instead of this, the oil passage 23 may be recessed on the outer peripheral surface of the connecting pin 13. Also, each bush 22
Since a substantially small gap is present between the connection pin 13 and the connecting pin 13, this gap itself may be used as an oil passage.

Further, in the above-described embodiment, each dust discharge passage 25 is described as extending in a substantially L-shaped manner, but each dust discharge passage 25 is provided with an oil passage 23 via the oil seal 24A side of each double lip type seal 24. May be formed so as to communicate with the outside. For example, the oil passage 23 on the right side in FIG. 1 is connected to the relief valve 26 on the right side, the oil passage 23 on the left side to the relief valve 26 on the left side via the oil seal 24A side, respectively. You may make it connect by communicating. On the other hand, it is not always necessary to provide two relief valves 26, and each dust discharge passage 25 may be connected in the middle to open and close a single relief valve 26.

Furthermore, in the above-described embodiment, the pin connecting device between the arm 5 and the bucket 6 of the hydraulic shovel is described as an example, but the present invention is not limited to this and may be applied to various pin connecting devices.

〔The invention's effect〕

According to the present invention described above, a double lip type seal formed of an oil seal and a dust seal is provided between the inner peripheral side of the boss portion and the outer peripheral surface of the connecting pin located on the axially outer side of the bush, and the double lip type seal is provided. When a dust discharge passage is formed in the boss so that the oil passage between the bush and the connecting pin communicates with the outside through the oil seal side of, when the pressure in the oil sump exceeds a predetermined pressure in the dust discharge passage. Since a relief valve that opens is provided, when the lubricating oil such as grease is filled in the oil reservoir and the pressure in the oil reservoir exceeds a predetermined pressure, the relief valve opens and a part of the lubricating oil is discharged to the outside. As a result, it is possible to easily confirm from the outside whether or not the lubricating oil is sufficiently filled in the oil sump and the like, and at the same time, abrasion powder and the like can be discharged. Further, since the double lip type seal is used, it is possible to prevent the lubricating oil from inadvertently leaking into seawater or the like, and to eliminate the pollution of seawater.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a vertical sectional view of a pin coupling device, FIG. 2 is an enlarged sectional view showing a double lip type seal and the like of FIG. 1, and FIG. An enlarged sectional view showing a relief valve and the like in FIG. 1, FIGS. 4 and 5 show a conventional technique, FIG. 4 is an overall view of a hydraulic shovel, and FIG. 5 shows an arm and a bucket in FIG. It is a longitudinal cross-sectional view which shows the principal part of the pin coupling device which couple | bonds. 13 …… Connecting pin, 15 …… Bracket, 21 …… Boss part, 21
A: Fitting hole, 21B: Oil sump, 21C: Seal groove, 22 ...
… Bush, 23 …… oil passage, 24 …… double lip type seal, 24A …… oil seal, 24B …… dust seal, 24C
…… Holding member, 24D …… Back pressure chamber, 24E …… Dust discharge hole,
25 …… Dust discharge passage, 26 …… Relief valve.

Claims (1)

(57) [Claims] 1. A boss portion of one member, a bush provided on both axial sides of the boss portion and provided in the boss portion, and the boss portion being rotatable with respect to a mating member through the bush. In a pin coupling device consisting of a coupling pin to be coupled and an oil reservoir provided in the boss located between the bushes, in order to guide the lubricating oil in the oil reservoir to the sliding surface of the bush and the coupling pin, From an oil passage provided between the bush and the connecting pin, and an oil seal and a dust seal located axially outside of the bush between the inner peripheral side of the boss and the outer peripheral surface of the connecting pin. And a dust discharge passage formed in the boss so as to communicate the oil passage with the outside through the oil seal side of the double lip seal, and the oil discharge passage provided in the dust discharge passage. Pin coupling device, wherein a and a relief valve which opens when equal to or greater than a predetermined pressure within Ri.