JPH07280103A - Seal device - Google Patents

Abstract

PURPOSE:To effectively prevent the occurrence of a seal defect by establishing the prescribed relationship among the breadth of an annular groove, the length of a seal material including a base section and the first lip, and the length of a seal material including the base section, the first lip and a projected section. CONSTITUTION:Regarding two lips 12 and 13 of a seal member 10, a projection 14 of less wall thickness than the first lip 12 for sealing the bottom of an annular groove 22 is formed on the forward end of the lip 12. Also, a relationship of B>A>C is established, provided that the breadth of the groove 22 is A, the axial length of the seal member 10 including a base section 11 and the first lip 12 is C, and the axial length of the seal member 10 including the base section 11, the first lip 12 and the projection 14 is B. As a result, the seal member 10 can be easily mounted on the groove 22, due to the deformation of the projection 14. In addition, the member 10 is supported on the base section 11, the first lip 12 and the projection 14 in the groove 22. Thus, the posture of the member 10 is not collapsed. At the same time, the deformation of the projection 14 has no effect on the first lip 12, thereby providing proper sealing function.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention fits into each other,
First and second members that move relative to each other in the axial direction,
The present invention relates to a sealing device, which is mounted in an annular groove provided on either one of the two members and includes a sealing member that seals the moving surfaces of both members, and particularly, by maintaining the sealing member in the annular groove in a stable posture. , A technique for effectively preventing a sealing failure of a sealing device. This invention is, for example,
It can be used as a sealing technique for a master cylinder or a wheel cylinder used in a brake circuit. Among these, the present invention is particularly useful for a master cylinder that requires not only a sealing function but also liquid replenishment.

[0002]

BACKGROUND OF THE INVENTION and Related Art As one of the sealing devices for sealing a moving part of this type, there is one using a lip type sealing member. The lip-type sealing member includes a thick-walled base portion and two lips extending from one side of the base portion. This lip-type seal member is mounted in an annular groove provided on the outer circumference of the piston of the master cylinder, as described in, for example, Japanese Utility Model Publication No. 4-23720, and the outer circumference of the piston is against the inner circumferential wall surface of the cylinder hole. Will be sealed.

In order to easily mount such a seal member in the annular groove, conventionally, the length of the seal member in the axial direction has been set to be slightly smaller than the width of the annular groove. Therefore, in the mounted state, there was a small clearance between the side wall surface of the annular groove and the end of the seal member. As a result of various studies, it has been found that this clearance causes a deterioration in the sealing property of the sealing member. For example, when the piston moves quickly, such as when a sudden brake is applied, the sliding resistance causes the seal member to move in the annular groove, which may cause the posture to collapse. Along with that, there arises a problem that the lip sealing function is lost. When the liquid replenishment property is required at the same time as the sealing property, the posture is collapsed, which causes a problem that the characteristic for the liquid replenishment becomes unstable.

As a means for solving such a problem, it can be considered to make the axial length of the seal member the same as the width of the annular groove to eliminate the clearance. However, since this seal member is molded by a mold, it is difficult to strictly control the length in the axial direction, and thus it is difficult to realize this.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is easy to mount the seal member in the annular groove, and the sealing member in the annular groove is maintained in a stable posture to provide a sealing device. It is an object of the present invention to provide a technique for effectively preventing a defective seal. Another object of the present invention is to provide a technique that does not impair the liquid replenishment property.

[0006]

[Means for that] As means for achieving the above purpose,
The present invention, as shown with reference to FIG. 1 corresponding to one embodiment, includes two lips 12 of a seal member 10,
A convex portion 14 thinner than the first lip 12 is provided at the tip of the first lip 12 that seals the bottom portion 25 of the annular groove 22 among the first lip 12. The width of the annular groove 22 is A, the axial length of the seal member 10 including the base portion 11 and the first lip 12 is C, and the seal member 10 including the base portion 11, the first lip 12 and the convex portion 14 is formed. Let B be the length of the axis direction of B, and B>A> C. This convex part 1
Usually, 4 is provided over the entire circumference, but a plurality of 4 may be provided with a gap in the circumferential direction so as to be cut out in the middle. The thickness of the convex portion 14 in the direction orthogonal to the axial direction of the seal member 10 is 1/2 or less of the thickness of the first lip 12 (for example, when the thickness of the first lip 12 is 1.8 mm, The thickness of the convex portion 14 is preferably about 1/3, which is about 0.5 mm). This thickness is the sealing member 10
When mounting the inside of the annular groove 22, the convex portion 14 can be easily deformed to be easily mounted, and at the time of mounting, the deformation of the convex portion 14 does not affect the first lip 12 side. It is the result of considering that the convex portion 14 can withstand the axial force due to the sliding resistance at the time of mounting.

Further, in order to make the mounting of the seal member 10 easier, it is preferable to provide a taper portion 15 between the first lip 12 and the convex portion 14. The tapered portion 15 needs to have a certain length, but the tapered portion 15 can be made smaller by providing a taper at the corner of the inner circumference of the base portion 11. Further, in order to bring the first lip 12 and the second lip 13 into contact with the side of the first or second member and to generate a more reliable sealing action, the annular groove 22
Before putting it on the two lips 12,13
It is preferable that each of them has an inclination so as to approach a member in contact with each other from the side of the base portion 11 toward the tip side.

[0008]

When the seal member 10 is mounted in the annular groove 22 provided on the outer peripheral wall surface 21 of the piston 20, the convex portion 14 comes into contact with the end portion of the annular groove 22 due to the above-mentioned dimensional relationship. . However, the convex portion 14 has the annular groove 2
The seal member 10 is smoothly mounted in the annular groove 22 because the seal member 10 is easily deformed by being compressed by the second side wall surface 24. That is, the length B of the seal member 10 shown in FIG.
The portion larger than the width A of 2 (the portion B-A) is the convex portion 1.
When 4 is compressed and deformed, it is as if absorbed by the convex portion 14. Moreover, the deformation of the convex portion 14 causes the second
Of course, it does not affect the lip 13 side,
There is almost no influence on the side of the first lip 12.
In this way, the seal member 10 is easily mounted in the annular groove 22 despite the presence of the protrusion 14. In the annular groove 22, the seal member 10 has a base portion 11 that contacts the side wall surface 26 on one side of the annular groove 22, a first lip 12 that contacts the bottom portion 25 of the annular groove 22, and the annular groove 2.
Side wall surface 24 on the side opposite to the side where the second base portion 11 is in contact
It is supported by the convex portion 14 that presses against. Therefore, since the seal member 10 has a small sliding resistance, it does not move in the annular groove 22 due to the axial force due to the sliding resistance, and maintains a stable posture even when the piston 20 moves. Therefore, the sealing device including such a sealing member 10 can surely obtain the sealing performance by the first and second lips 12 and 13. Further, when such a sealing device is used for the master cylinder, the posture of the sealing member 10 is stable, so that the liquid replenishment property is not impaired at the same time as the sealing property.

[0009]

1 is a half sectional view of a sealing member 10 which is a main part of a sealing device according to a first embodiment of the present invention. The seal member 10 is, for example, an annular groove 22 cut in the outer peripheral wall surface 21 of the piston 20 of the master cylinder.
It is installed inside. In FIG. 1, the annular groove 22 is shown by a dotted line so that the magnitude relationship between the axial length of the seal member 10 and the width of the annular groove 22 can be easily understood. In FIG. 1, the annular lip-type seal member 10 is
It includes two lips 12, 13 each extending from one side of the thick base portion 11. Of these, the first lip 12 located on the inner peripheral side is inclined so as to approach the bottom portion 25 of the annular groove 22 of the piston 20 as it goes toward the tip thereof.
Further, the second lips 13 located on the outer peripheral side each have an inclination so as to approach the inner peripheral wall surface of the cylinder (not shown) toward the tip thereof. This first lip 1
A convex portion 14 is provided on the tip portion of the entire circumference of 2.
Further, a taper portion 15 is provided between the first lip 12 and the convex portion 14 for facilitating mounting of the seal member 10 in the annular groove 22. Particularly, in the seal member 10 according to the first embodiment, the taper portion 15 is provided up to the tip of the convex portion 14, and the thickness becomes thinner toward the tip, so that the seal member 10 can be more easily mounted in the annular groove 22. It will be easy. FIG. 2 is an enlarged cross-sectional view showing how the seal member 10 is mounted in the annular groove 22. As shown in this figure, the seal member 10 is easily mounted in the annular groove 22 by the deformation of the convex portion 14, and in the annular groove 22, the base portion 11,
The posture is not disturbed by being supported by the first lip 12 and the convex portion 14. Moreover, the deformation of the convex portion 14 does not affect the first lip 12, and a reliable sealing property can be obtained.

FIG. 3 is a second embodiment of the present invention, and is a half sectional view of a seal member 100 mounted on, for example, the piston 20 of the master cylinder, as in the first embodiment. This figure also shows the magnitude relationship between the axial length of the seal member 100 and the width of the annular groove 22. Figure 4
FIG. 6 is an enlarged cross-sectional view showing a state where the seal member 100 is mounted in the annular groove 22. The major difference between the second embodiment and the first embodiment is the convex portion 140. Since the other parts are almost the same as those shown in the first embodiment, in FIGS. 3 and 4, the same parts are shown by the same numbers as in the first embodiment. Particularly, in the seal member 100 according to the second embodiment, the convex portion 1
The cross-sectional shape of 40 was set to be substantially rectangular so as to maintain a more stable posture when attached. When the seal member 100 is mounted in the annular groove 22, the deformation of the convex portion 140 substantially follows the axial direction of the piston 20, so that the force due to the deformation acts on the side wall surface 24 in the axial direction. . Therefore, the deformation of the convex portion 140 causes the first lip 12 to deform.
Almost no adverse effect is exerted on the sealing action due to.

In any of the embodiments, the seal member 1
The relationship between 0, 100 and the annular groove 22 is that the width of the annular groove 22 is A, the axial length of the seal member 10, 100 including the base portion 11 and the first lip 12 is C, the base portion 11, the first portion. B>A> C, where B is the axial length of the seal member 10, 100 including the lip 12 and the protrusions 14, 140.
Is set.

According to the results of research, this seal member 1
Maximum error in the molding process of 0,100 is ± 0.2mm
Therefore, the height (the length in the axial direction) of the convex portions 14 and 140 is preferably about 0.3 mm in consideration of this error. By doing so, even if an error occurs in the molding process, it is possible to always provide the sealing members 10 and 100 with a tightening margin of 0.1 mm or slightly exceeding it. Note that the seal members 10 and 100 are rubber molded products, and the protrusions 14 and 140 can be formed integrally with the first lip 12 by molding.

Further, in both the first and second embodiments, the seal members 10 and 100 can be mounted relatively easily, so that the seal members 10 and 100 are mounted in the annular groove 22 cut in the outer peripheral wall surface 21 of the piston 20. I'm doing this piston 2
It may be provided on an inner peripheral wall surface in a cylinder hole (not shown) that moves relative to zero.

[0014]

The sealing device according to the present invention is, for example, a sealing member 10, 100 fitted in an annular groove 22 cut in an outer peripheral wall surface 21 of a piston 20 of a master cylinder.
At the tip of the first lip 12 that is in contact with the bottom portion 25 of the annular groove 22, the convex portions 14 and 140 are provided, the width of the annular groove 26 is A, and the seal member 10 and 100 including the base portion 11 and the first lip 12 are provided. The axial length is C, the base portion 11,
Assuming that the axial length of the seal member 10, 100 including the first lip 12 and the convex portions 14, 140 is B, B>A>
By setting the relationship of C, the mounting in the annular groove 22 is facilitated, and the annular groove 22 of the seal member 10, 100 is provided.
By maintaining a stable posture inside, seal failure is effectively prevented. In particular, even when liquid replenishment is required, the sealing device according to the present invention does not impair the liquid replenishment characteristics.

[Brief description of drawings]

FIG. 1 is a half sectional view of a seal member according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing how the seal member shown in FIG. 1 is attached.

FIG. 3 is a half sectional view of a seal member according to a second embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view showing how the seal member shown in FIG. 3 is attached.

[Explanation of symbols]

 10,100 Seal member 11 Base portion 12 First lip 13 Second lip 14,140 Convex portion 15 Tapered portion 22 Annular groove 25 Bottom portion

Claims (5)

[Claims] 1. A first member and a second member which are fitted into each other and relatively move in the axial direction, and both members which are mounted and moved in an annular groove (22) provided in either one of the first and second members. An annular seal member (10, 1) that seals between the
00), wherein the sealing member (10, 100) respectively extends from a thick base portion (11) and one side of the base portion (11), and the annular groove (22). First lip (12) contacting the bottom (25) of the
In addition, the annular groove (2
In the one including a second lip (13) which is in contact with the side of the member different from the member provided with 2), the first lip (1
2) A convex portion (14, 140) thinner than that of 2) is provided, and the convex portion (14, 140), the first lip (12) and the base portion (11), and the annular groove (22). The seal device is characterized in that the dimensional relationship along the axial direction with the width of the seal is set as follows. The annular groove (2
The width of 2) is A, the base portion (11) and the first lip (1
2) The length of the seal member (10, 100) including and is C,
There is a relationship of B>A> C, where B is the length of the seal member (10, 100) including the base portion (11), the first lip (12) and the convex portion (14, 140). 2. The sealing device according to claim 1, wherein the convex portions (14, 140) are provided on the entire circumference of the first lip (12). 3. The sealing device according to claim 1, wherein the thickness of the protrusions (14, 140) is not more than 1/2 of the thickness of the first lip (12). 4. The seal member (1) is provided between the first lip (12) and the tip of the convex portion (14, 140).
The sealing device according to any one of claims 1 to 3, wherein a taper portion (15) is provided for facilitating mounting of (0, 100) in the annular groove (22). 5. The first and second lips (12, 13) of the seal member (10, 100) before being mounted in the annular groove (22) have the base portion (11).
The sealing device according to any one of claims 1 to 4, wherein the sealing device has an inclination so as to approach members contacting each other from the side toward the tip side of each lip (12, 13).