JPH0194128A - Pin connector - Google Patents

Abstract

PURPOSE:To prevent the leakage of lubricating oil in an oil trap by providing a double-lip type seal between a boss and a connecting pin, a dust discharge path formed in the boss, and a relief valve to be opened when the internal pressure of the oil trap exceeds a given pressure. CONSTITUTION:A pin connector device consists of the boss 21 of one part, a bush 22 positioned on both sides of the radial direction, a connecting pin 13 to rotatably connect the boss 21 to the counter part through the bush 22, and an oil trap 21B provided in the boss 21 between the bushes 22, together with an oil path 23 to direct lubricating oil in the oil sump 21B to the slide face between the bush 22 and the pin 13 and a seal 24 consisting of an oil seal 24A and a dust seal 24B between the inner surface of the boss 21 and the periphery of the pin 13. A dust discharge path 25 connecting the oil path 23 to the outside through the oil seal 24A side and a relief valve 26 to be opened when the internal pressure of the trap 21B exceeds a given one are also provided. The lubricating face can thus be well lubricated even in sea water for long periods of time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pin coupling device used in construction machinery such as a hydraulic excavator, and in particular, the sliding surface of the bush and the connecting pin can be easily maintained even when working in seawater or the like. This invention relates to a pin coupling device that is capable of lubricating the body over a long period of time.

[Conventional technology]

FIGS. 4 and 5 show a conventional pin coupling device using a hydraulic excavator 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 part 3 is provided at the front part of the upper revolving body 2. The working section 3 is connected to a boom 4. It is roughly composed of an arm 5 and a packet 6,
These are operated by a boom cylinder 7, an arm cylinder 8 and a packet cylinder 9, respectively. Here, the boom 4, arm 5, packet 6, boom cylinder 7, arm cylinder 8, bucket cylinder 9, etc. are connected to pin coupling devices 10.10.・・・・・・・・・
They are each connected by...

Next, arm 5. A pin coupling device 10 that couples packets 6 will be described 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, there are insertion holes 11A for bushings 12, which will be described later, located on both sides in the axial direction. (However, only one is shown in FIG. 5).

A large-diameter oil reservoir 11B is formed at an axially intermediate portion between each of the insertion holes 11A so as to be recessed on the inner peripheral side of the boss part 1. Further, a seal #11C is provided at the outer end in the axial direction of each of the insertion holes 11A, and the seal groove 1
A dust seal 16, which will be described later, is attached to 1C. Reference numeral 12 denotes a cylindrical bushing inserted into each of the fitting holes IIA, and a connecting pin 13, which will be described later, is slidably inserted into the bushing 12.

Reference numeral 13 denotes a connecting pin which rotatably connects the boss portion 11 to a bracket 15 (described later) via the bush 12;
A large diameter stop plate 14 is attached to the tip of the connecting pin 13, and the stop plate 14 prevents the connecting pin 13 from coming off. Reference numeral 15 denotes a bracket provided on the packet 6 which is the counterpart member of the arm 5. Two of the brackets 15 protrude from the main body of the packet 6 at a predetermined interval in the width direction. They are arranged with a predetermined gap S in between (however, only one is shown in FIG. 5). The bracket 15 has a pin hole 1 in the axial direction.
5A is drilled, and the connecting pin 13 is inserted into the bottle hole 15A.
is inserted. Furthermore, 16 is the seal groove 11c.
The dust seal 16 slides on the outer peripheral surface of the connecting pin 13 and prevents rainwater, muddy water, etc. from entering the sliding surface of the bushing 12 and the connecting pin 13 from outside. ing.

The pin coupling device 1 for a hydraulic excavator according to the prior art has the above-mentioned configuration.
The interior is filled with lubricating oil such as grease. The lubricating oil in the oil reservoir JIB is
is guided to the sliding surface of the connecting pin 13, and an oil film is formed on this sliding surface to lubricate this sliding surface.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional technology, since only the dust seal 16 is provided in the seal groove 11G of the boss portion 11, it is possible to prevent rainwater, muddy water, etc. from entering the sliding surfaces of the bushing 12 and the connecting pin 13 from the outside. However, there is a drawback that it is not possible to reliably prevent the lubricating oil in the oil reservoir IIB from leaking to the outside via the sliding surface. In particular, when submerging the tip side of the packet 6 or arm 5 in seawater or the like to allocate and remove earth and sand from the seabed, the lubricating oil in the oil reservoir IIB flows through the sliding surface and the dust seal 16. There is a drawback that it may leak into seawater, and lubricating oil such as grease must be re-injected into the oil reservoir IIB about once every half day, for example. Furthermore, there is a drawback that the leakage 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 seal consisting of an oil seal and a dust seal to prevent lubricating oil in the oil reservoir from inadvertently leaking to the outside. It is possible to prevent this from occurring, and the sliding surfaces of the bushing and connecting pin can be lubricated for a long time even when working in seawater, etc., and when injecting lubricating oil into the oil reservoir,
It is an object of the present invention to provide a pin coupling device in which it is possible to easily check from the outside whether or not the lubricating oil is sufficiently filled.

[Means for solving problems]

The feature of the configuration adopted by the present invention in order to solve the above-mentioned problems is that the lubricating oil in the oil reservoir is provided between the bushing and the connecting pin in order to guide the lubricating oil to the sliding surface of the bushing and the connecting pin. a double-lip type seal consisting of an oil seal and a dust seal located on the axially outer side of the bushing and provided between the inner circumferential side of the boss portion and the outer circumferential surface of the connecting pin; A dust discharge passage formed in the boss portion so as to communicate the oil passage with the outside through the oil seal side, and a relief provided in the dust discharge passage that opens when the pressure inside the oil reservoir exceeds a predetermined pressure. This is because it is equipped with a valve.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3. In the embodiment, the same components as those of the prior art shown in FIGS. 4, 5, and 5 are given the same reference numerals, and their explanations will be omitted.

In the figure, reference numeral 21 denotes a boss portion provided at the tip of the arm 5 as one member, and the boss portion 21 is formed almost in the same way as the boss portion 11 used in the prior art. Insertion holes 21A, 21A for 22, oil reservoir 21
B and seal grooves 21C, 21C are provided, respectively. Further, a nipple 21B is provided in the radial direction of the boss portion 21 via an injection hole 21D in order to inject lubricating oil such as grease into the oil reservoir 21B. Reference numerals 22 and 22 denote bushings used in this embodiment that are fitted into the respective fitting holes 21A, and 23 and 23 are oil passages for guiding the lubricating oil in the oil reservoir 21B to the sliding surfaces of the bushings 22 and the connecting pin 13. Each of the oil passages 23 is recessed in the inner peripheral surface of the bushing 22 over the entire length in the axial direction.

24.24 is a double lip type seal installed in each of the seal grooves 2IC, and each of the double lip type seals 24 is an oil seal 2 located on the inside in the axial direction as shown in FIG.
4A, and a dust seal 24B located on the outer side in the axial direction,
Each seal 24A.

24B in each seal groove 21C.
4C, and the lip portion of each seal 24A, 24B is in sliding contact with the outer peripheral surface of the connecting pin 13. Here, the dust seal 24B prevents rainwater, muddy water, etc. from entering from outside into the sliding surfaces of the bushing 22 and the connecting pin 13 through the gap S. On the other hand, the oil seal 24A
forms a back pressure chamber 24D between the bushing 22 and the end surface of the bushing 22;
The inside of the back pressure chamber 24D is connected to an oil reservoir 21B via the oil passage 23.
It communicates with 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 reservoir 21B, thereby preventing this lubricating oil from leaking to the outside. ing. Further, a dust discharge hole 24E is provided at the base end side of the oil seal 24A, passing through the holding member 24C, and the dust discharge hole 24E communicates a back pressure chamber 24D with a dust discharge passage 25, which will be described later.

25.25 is a dust discharge passage formed in the boss portion 21 so as to communicate each oil passage 23 with the outside via the oil seal 24A side of each double lip type seal 24, and each dust discharge passage 25 is connected to the boss portion 21. The circumferential wall of the portion 21 extends in the radial and axial directions, and the base end thereof is connected to the back pressure chamber 2 through the dust discharge hole 24E on the oil seal 24A side.
It communicates with 4D. The tip side of each dust discharge passage 25 is a dust discharge part 2 formed with a relatively large diameter.
5. A, 25A, and the tips of each dust discharge part 25A are open at both axial end faces of the boss part 21 so as to face the inner surface of each bracket 15 through each gap S.

26.26 is the dust discharge part 25 of each dust discharge passage 25
As shown in FIG. 3, each of the relief valves 26 has a valve seat 26A provided on the proximal end surface of each dust discharge part 25A, and a relief valve installed in the valve seat 26A. A ball 26B that seats and separates from each other to open and close each dust discharge passage 25A to the outside, and a spring 26C that always biases the ball 26B in the valve closing direction are attached to each dust discharge portion 25A in order to hold the spring 26C. A dust discharge hole 26E having a small diameter is bored in the center of the plug 26D in the axial direction. Each relief valve 26 injects lubricating oil such as grease into the oil reservoir 21B, opens when the pressure inside the oil reservoir 21B exceeds a predetermined pressure, and closes when the pressure drops below a predetermined pressure. There is.

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

First, when injecting lubricating oil such as grease into the oil reservoir 21B, the lubricating oil such as grease is injected into the oil reservoir 21B from the nipple 21E using, for example, a grease gun. The lubricating oil injected into the oil reservoir 21B is guided to the sliding surface between each bushing 22 and the connecting pin 13 through the oil passage 23 of each bushing 22, and forms an oil film on this sliding surface. , a back pressure chamber 24D between the oil seal 24A of each double lip type seal 24 and the end face of each bushing 12;
The oil flows into the oil seal 24A due to its hydraulic pressure.
The lip portion of the connecting pin 13 is pressed against the outer peripheral surface of the connecting pin 13. As a result, the oil seal 24A can reliably prevent the lubricating oil in the oil reservoir 21B from leaking to the outside along the outer peripheral surface of the connecting pin 13.

Next, when each back pressure chamber 24D is filled with lubricating oil from the oil reservoir 21B, this lubricating oil flows out to each dust exhaust passage 25 via the dust exhaust hole 24E on each oil seal 24A side. Then, the spring 2 holds the pole 26B of each relief valve 26 located at the tip side of each dust discharge passage 25.
Press against 6C. When the oil reservoir 21B reaches a predetermined pressure or higher due to the injection of lubricating oil, each relief valve 26 is opened by the pressure at this time, and a part of the lubricating oil is discharged from each dust discharge part 25A to the dust of each plug 26D. The lubricating oil is released into each gap S between the boss portion 21 and each bracket 15 through the hole 26B, and the gap S can be lubricated. It is possible to easily check from the outside whether or not the injection process is complete.

On the other hand, abrasion powder and air remaining in the oil reservoir 21B1, the sliding surfaces of each bush 22 and the connecting pin 13, the back pressure chamber 24D, etc. are removed from each dust discharge passage 25 by the lubricating oil injection operation.
The oil is then discharged to the outside via each relief valve 26, which prevents abrasion particles from remaining in the oil reservoir 21B, sliding surfaces, etc., and cleans the sliding surfaces, etc. every time injection work is performed. can be converted into

Thus, according to this embodiment, when injecting lubricating oil such as grease, it is possible to easily check from the outside whether or not the lubricating oil is sufficiently filled in the oil reservoir 21B, etc. The outer peripheral surface and the dust discharge passage 25 can be reliably sealed by the oil seal 24A and the relief valve 26, and the lubricating oil can be reliably prevented from inadvertently leaking to the outside. Therefore, even when working with the packet 6 or the tip end of the arm 5 submerged in water or seawater, it is possible to reliably prevent lubricating oil from leaking into the water or seawater.
The sliding surfaces of 2 and the connecting pin 13 can be lubricated for a long time. In addition to preventing contamination of foreign countries and water by the lubricating oil, the dust seal 24B can prevent seawater and the like from entering.

In the above embodiment, the oil passages 23 were recessed in the inner circumferential surface of each bushing 22, but instead of this, the connecting pins 1
The oil passage 23 may be recessed in the outer circumferential surface of 3. Moreover, since there is a substantially small gap between each bushing 22 and the connecting pin 13, this gap itself may be used as an oil passage.

Further, in the above embodiment, each dust discharge passage 25 is omitted and is described as extending in the following shape, but each dust discharge passage 25 is connected to the oil seal 2 of each double lip type seal 24.
4. Each oil passage 23 may be formed to communicate with the outside via the A side, for example, the oil passage 23 on the right side in FIG. 1 is connected to the right relief valve 26, and the oil passage 23 on the left side is connected to the left relief valve 26 may be communicated with each other through the oil seal 24A side. On the other hand, it is not always necessary to provide two relief valves 26, and each dust discharge passage 25 may be communicated in the middle, and a single relief valve 26 may be opened and closed.

Further, in the above embodiment, the arm 5 of the hydraulic excavator. Although the description has been given using a pin coupling device between packets 6 as an example, the present invention is not limited to this, and may be applied to various pin coupling devices.

〔Effect of the invention〕

According to the present invention described above, a double-lip type seal consisting 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 bushing. A dust discharge passage is formed in the boss portion so that the oil passage between the bushing and the connecting pin communicates with the outside through the oil seal side of the mold seal, and the dust discharge passage has an oil reservoir whose pressure is higher than a predetermined pressure. We installed a relief valve that opens when the oil reservoir is filled with lubricating oil such as grease, and when the pressure inside the core oil reservoir exceeds a predetermined pressure, the relief valve opens and some of the lubricating oil is released. This allows it to be discharged to the outside, making it easy to check from the outside whether the lubricating oil is sufficiently filled in the oil reservoir, etc., and also to discharge wear particles and the like at the same time. Furthermore, since a double lip type seal is used, it is possible to prevent lubricating oil from inadvertently leaking into seawater and the like, thereby eliminating seawater contamination.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention, in which FIG. 1 is a vertical sectional view of a pin coupling device, FIG. 2 is an enlarged sectional view showing the double lip type seal etc. of FIG. 1, and FIG. is an enlarged sectional view showing the relief valve etc. in Fig. 1, Figs. 4 and 5 show the prior art, Fig. 4 is an overall view of the hydraulic excavator, and Fig. 5 is an arm and packet in Fig. 4. FIG. 13......Connection pin, 15...
...Bracket, 21...Boss part, 21
A......Insert hole, 21B...
・Oil reservoir, 21C...Seal groove, 22・
...... Bush, 23... Oil passage, 24... Double lip type seal, 2
4A・・・・・・Oil seal, 24B・・・・
...Dust seal, 24C...Holding member, 24D...Back pressure chamber, 24E...
・・・・・・Dust discharge hole, 25・・・・・・・・・
Dust discharge passage, 26...Relief valve. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] a boss portion of one member; a bush located on both sides of the boss portion in the axial direction and provided within the boss portion; and a connecting pin rotatably connecting the boss portion to the other member via the bush; In a pin coupling device comprising an oil reservoir located between the bushes and provided in the boss portion, the bush and the coupling pin are connected to each other in order to guide lubricating oil in the oil reservoir to the sliding surfaces of the bush and the coupling pin. a double lip type seal consisting of an oil passage provided between the bushing and an oil seal and a dust seal located on the axially outer side of the bush and provided between the inner peripheral side of the boss portion and the outer peripheral surface of the connecting pin; a dust discharge passage formed in the boss portion so as to communicate the oil passage with the outside via the oil seal side of the double lip seal; and a dust discharge passage provided in the dust discharge passage;
A pin coupling device comprising a relief valve that opens when the pressure inside the oil reservoir reaches a predetermined pressure or higher.