JPH0341167Y2 - - Google Patents

Description

[Detailed Description of the Invention] a. Field of Industrial Application The present invention relates to an improvement in the grease groove of a piston disposed in a hydraulic cylinder portion of a clutch actuator.

b. Prior Art As shown in FIG. 6, a clutch actuator 1 is mainly composed of a power cylinder section 1 and a hydraulic cylinder section 2, and a power piston 3 is activated by supplying and discharging compressed air to and from the power cylinder section 1. is reciprocated, and this movement is transmitted to the output rod 6 via the first piston 4 and second piston 5 of the hydraulic cylinder section 2, so that the clutch is operated to open or disconnect. An oil chamber 7 is formed between the first piston 4 and the second piston 5, and this oil chamber 7 allows the first piston 4 to
The distance between the second piston 5 and the second piston 5 is regulated. That is, the oil chamber 7 is normally connected to the oil reservoir 9 through the passage 8 of the first piston 4.
However, when the power piston 3 moves forward, the valve body 10 closes the passage 8 and seals the oil chamber 7, thereby reducing the distance between the first piston 4 and the second piston. are becoming regulated. Since the passage 8 is normally open, the output rod 6 is allowed to retreat to the left in FIG. 6 due to wear of the clutch plate, thereby preventing the clutch release position from shifting.

By the way, as shown in FIG. 7, two seal rings 13 and 14 are provided on the outer peripheral surface of the second piston 5.
These seal rings 13 and 14 prevent oil from leaking from the oil chamber 7 or air from entering the oil chamber 7. Specifically, one seal ring 13 has a U-shaped cross section, and is designed to mainly prevent oil leakage. Also,
The other seal ring 14 has an X-shaped cross section, and is designed to mainly prevent air from entering.

The seal ring 14 has a pair of left and right lip portions 1.
4a and 14b, and these pair of lip portions 14
a, 14b are in sliding contact with the inner circumferential surface of the cylinder 1, thereby preventing air from entering the oil chamber 7.
However, the inner circumferential surface of the cylinder where the pair of lip portions 14a, 14b are in sliding contact is a so-called dry sliding surface with almost no oil attached, and therefore damage caused by friction between the pair of lip portions 14a, 14b is a problem. Especially the outer lip part 14b
Since it is directly exposed to the air, there is a risk of friction damage in a relatively short period of time.

Therefore, conventionally, a pair of annular grease grooves 15 and 16 are formed adjacent to the left and right sides of the seal ring 14.
The lip portions 14a and 14b of the seal ring 14 are lubricated by the grease groove 17 filled in the pair of grease grooves 15 and 16.

c Problems to be solved by the invention The grease grooves 15 and 16 of the second piston 5 of the conventional hydraulic cylinder section 2 are constructed as described above, but among these grease grooves 15 and 16, especially the outer grease groove Regarding No. 16, the following problems have been pointed out. That is, since the outer grease groove 16 is directly exposed to the air, the grease 17 filled in this groove 16 may dry and shrink in a relatively short period of time, or the clutch actuator may be damaged. The grease 17 exhibits excessive fluidity due to the thermal influence of the exhaust pipe of an engine routed nearby, and as a result, there is a risk that the grease 17 will leak out to the outside and disappear within a relatively short period of time. If the grease shrinks or disappears in this manner, the outer lip portion 14b of the seal ring 14, in particular, will be damaged due to friction with the inner peripheral surface of the cylinder.

The present invention has been devised to effectively solve the above-mentioned problems, and its purpose is to provide a grease groove for a piston in which the lubricating action of grease can work satisfactorily over a long period of time. .

d Means for Solving the Problems In order to solve the above-mentioned problems, the present invention covers the opening of the grease groove with a cylindrical lid member, and also connects the inside of the grease groove to the vicinity of the seal ring through a narrow passage. It is connected.

e. Effect In the present invention configured as described above, the grease groove is covered with the lid member, so the grease in the groove is difficult to dry, and even if the grease exhibits excessive fluidity due to the influence of heat, it can easily flow outside. The grease in the groove continues to seep into the vicinity of the seal ring for a long period of time through the narrow passage without fear of seepage, thereby maintaining the lubrication of the seal ring for a long period of time and increasing the life of the ring.

f Example An example of the present invention will be described below based on the drawings.

1 to 5 show different embodiments of the present invention, and FIG. 1 shows a grease groove 1.
6 is covered with a ring-shaped lid member 19. Specifically, the lid member 19 is formed by processing a band-shaped sheet metal or plastic material into a ring shape, and its width is slightly narrower than the width of the opening 18, so that the opening 18 and the lid member 19 are
A narrow gap 20 is formed between them.

Next, FIG. 2 shows a ring-shaped lid member 2 in the opening 18.
1 are fitted together without any gaps, and a large number of small holes 22 are formed in this lid member 21.

Next, FIG. 3 shows a ring-shaped lid member 23 having an L-shaped cross section fitted into the grease groove 16.
The width of this lid member 23 is made slightly narrower than the width of the opening 18, so that the opening 18 and the lid member 2
3, a narrow gap 24 is formed between the two.

Next, FIG. 4 shows a ring-shaped lid member 2 in the opening 18.
The grease groove 16 and the fitting groove 26 of the seal ring 14 are connected through a plurality of small holes 27.

Next, FIG. 5 shows a ring-shaped lid member 28 having an L-shaped cross section fitted into the grease groove 16.
The width of this lid member 28 is made slightly narrower than the width of the opening 18, so that the opening 18 and the lid member 2
8, a narrow gap 29 is formed between the two. Furthermore, the grease groove 16 communicates with the atmosphere-side end surface 31 of the second piston 5 through a plurality of small holes 30 .

In FIGS. 1 to 5, the configurations of other parts are the same as those of the conventional device shown in FIG. 6, and therefore their explanations will be omitted.

The grease groove 16 of the second piston 5 is constructed as described above, and in the case of the grease groove 16 shown in FIGS. It passes through the cylinder and gradually seeps into the sliding surface of the cylinder. On the other hand, since the grease groove 17 within the groove 16 is covered with the lid members 19, 21, and 23, it is extremely difficult to dry, and there is no risk of the grease 17 shrinking in a short period of time as in the conventional case.

Further, in the case of the grease groove 16 shown in FIG. 4, the grease 17 in the groove 16 gradually leaks out to the side of the outer lip portion 14b of the seal ring 14 through the small hole 27. In this case as well, since the grease 17 in the groove 16 is covered with the lid member 25, it is difficult to dry or shrink.

Furthermore, in the case of the grease groove shown in FIG. 5, the grease 17 in the groove 16 gradually seeps out through the gap 29. At this time, when the exhaust pressure during the backward movement of the power piston acts on the atmospheric side end surface 31 of the second piston 5, this pressure passes through the small hole 30 and into the groove 16.
It acts on the grease 17 inside and forcibly pushes the grease 17 out through the gap 29. Therefore, the grease 17 in the groove 16 can be used up to the end,
Lubrication life can be significantly improved. The passage route of the exhaust pressure will be explained with reference to FIG. 6. This exhaust pressure is transmitted from the power cylinder section 1 through a valve (not shown), through the inlet of the atmospheric valve 32, and further through the tube 33 into the waterproof boot 34. It is introduced and acts on the atmosphere side end surface 31 of the second piston 5.

Although one embodiment of the present invention has been described above, the present invention is limited to the above-mentioned embodiment because the present invention basically requires that the grease groove 16 be closed and the inside thereof communicated with the cylinder sliding surface through a narrow passage. Various modifications are possible without modification.

g. Effects of the invention As mentioned above, in this invention, since the grease groove is covered with a cover member, there is no problem such as the grease drying out or shrinking in a short period of time. Even in the case of excessive fluidity, it seeps into the cylinder sliding surface little by little over a long period of time through narrow passages, which maintains the lubrication of the seal ring for a long period of time and extends the life of the ring. In addition, the maintenance burden of this type of device can be reduced.

[Brief explanation of the drawing]

1 to 5 are sectional views of pistons according to embodiments of the present invention, respectively. 6 is a longitudinal sectional view of a conventional clutch actuator, and FIG. 7 is a sectional view of the same actuator similar to FIG. 1. 13, 14... Seal ring, 15, 16...
Grease groove, 17... Grease, 18... Opening, 19, 21, 23, 25, 28... Lid member,
20, 24, 29... Gap (narrow passage), 22,
27...Small hole (narrow passage).

Claims (1)

[Scope of utility model registration request] In an annular grease groove formed adjacent to the seal ring of the piston that makes sliding contact with the dry sliding surface of the cylinder and filled with grease for lubricating the seal ring, the opening of the grease groove is covered with a ring-shaped lid. A grease groove for a piston, characterized in that the grease groove is covered with a member and the inside of the grease groove is communicated with the vicinity of the seal ring through a narrow passage.