JP2003329143A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device which prevents a seal lip from abutting surface-to-surface. <P>SOLUTION: This sealing device is provided with a metal ring 14 comprising an outer peripheral part 14a and a flange part 14b, and a seal lip 11a. The root of the seal lip is fixed to the metal ring so that it covers the outer peripheral part 14a. A part 12a of a surface extending toward the root covering the outer peripheral part 14a from the tip of the seal lip enters into the inner diameter side of a surface 13a which extends from the surface of the root of the seal lip in an axial direction. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device used for reducing the influence of centrifugal oil pressure acting on a hydraulic piston of an automatic transmission for automobiles and the like.

[0002]

2. Description of the Related Art In an automatic transmission used for an automobile or the like, a CVT (multi-disc clutch is controlled by a pressing force of a hydraulic piston which is moved by applying hydraulic pressure in a rotating state to perform shift control. Continuously Va
The riable transmission is widely known.

The schematic structure of the shift switching portion of the CVT will be briefly described with reference to FIG. FIG. 4 is a semi-sectional view of a schematic configuration of the gear shift unit, showing only one side (the right side is omitted in FIG. 4) of the rotary shaft 101 inserted into the housing 100. The inner peripheral surface of the housing 100 and the outer peripheral surface of the rotary shaft 101 form an annular piston chamber 102.

A multi-plate clutch 103 is provided inside the housing 100, and a cylindrical piston member 104 having a bottom is arranged in the piston chamber 102 so as to be axially strokeable. Further, a cancel plate 105 is attached to the outer circumference of the rotary shaft 101 as an annular restriction member that restricts movement in the axial direction. The cancel plate has a protrusion 105a on the inner periphery thereof, and a stopper 106 provided on the rotating shaft 101 is positioned on the inner periphery side of the protrusion 105a to restrict movement.

Further, a seal lip 107 as a seal member is provided on the outer peripheral surface of the cancel plate 105, and the seal lip 107 is in sealing contact with the inner peripheral surface of the outer peripheral side cylindrical portion 104a of the piston member 104.

Between the cancel plate 105 and the piston member 104, a plurality of coil springs 108 for urging the piston member 104 away from the cancel plate 105 are arranged in the circumferential direction.

The piston member 104 biased by the spring 108 comes into contact with the end surface 100a of the housing 100 through the rubber-like elastic body 110 and stands still.

Further, a seal lip is used as a sealing member which is in sealing contact with the respective outer peripheral surfaces of the piston member 104 so as to seal the outer peripheral surface of the rotary shaft 101 and the outer peripheral surface thereof to seal the inner peripheral surface of the housing 100. 111,112
Is provided.

In this way, the pressure chamber X and the oil chambers Y and Z are formed in the housing 100 separately.

In the above structure, when the hydraulic pressure (arrow P) acts on the pressure chamber X and the pressure rises, the piston member 104
Strokes against the urging force of the spring 108 toward the cancel plate 105 (downward in the figure), and presses the multi-plate clutch 103 at the end of the outer peripheral side cylindrical portion 104a of the piston member 104. As a result, the clutch plate provided on the housing 100 side makes frictional contact with the clutch plate on the output shaft (not shown) side, and the rotational driving force of the housing 100 is transmitted to the output shaft.

When the transmission of power by the multi-plate clutch 103 is released, the pressure in the pressure chamber X is lowered and
By supplying oil to the oil chamber Y, the piston member 104 is stroked toward the end surface 100a of the housing 100 by the biasing force of the spring 108.

As described above, the piston member 104 and the cancel plate 105 rotate and move in the axial direction by receiving the hydraulic pressure, and the seal lip 107, the seal lips 111, 112, etc. are integrally formed on the base material. It functions as a so-called bonded piston seal (sealing device) 1.

By the way, in an oil chamber whose outer peripheral side is hermetically sealed like the high-pressure oil chamber X, a centrifugal force acts on the hydraulic oil when the housing 100 rotates, and a centrifugal hydraulic pressure is applied to the piston member 104 in addition to the hydraulic pressure. The phenomenon that "acts" occurs. This centrifugal hydraulic pressure increases in proportion to the square of the distance from the center of rotation of the housing 100, so that a non-uniform force that increases toward the outer peripheral side acts on the piston member 104. This phenomenon not only makes it difficult to control the operating oil pressure, but also affects the operation of the piston member 104 and causes damage to the piston 104.

The above-mentioned bonded piston seal 1 is
It is provided in order to reduce the influence of the centrifugal oil pressure acting on the piston member 104.

That is, by forming the oil chamber Y on the low-pressure oil chamber Z side of the piston member 104 by the bonded piston seal 1, centrifugal oil pressure due to the rotation of the housing 100 is also generated in this oil chamber Y. The centrifugal oil pressure in the oil chamber Y acts as a force for urging the piston member 104 toward the high pressure oil chamber X side, so that the centrifugal oil pressure on the high pressure oil chamber X side can be offset.

In this structure, when the hydraulic pressure (arrow P) acts on the high-pressure oil chamber X, a pressure of about 2 MPa is applied to the piston member in the high-pressure oil chamber X, so that the seal lips 111, 112 provided on the piston member are deformed. However, there has been a concern that the inner peripheral surface of the housing or the outer peripheral surface of the rotating shaft, which is the contacted portion, may be clogged with a sticking material, which may cause abnormal wear of the seal lip.

As a countermeasure to this, the rigidity of the seal lip is increased so that the seal lip is not deformed even when an extremely high pressure is applied to prevent sticking.

However, when the seal lip having the increased rigidity is used, the sliding resistance between the seal lip and the contacted member increases, which hinders the smooth movement of the piston member. Was there. Therefore, when low sliding resistance is required, the rigidity of the seal lip is lowered in order to reduce the sliding resistance.

[0019]

However, in the case of the above-mentioned prior art, in order to reduce the sliding resistance between the housing 100 and the piston member 104, the seal lip 111 and the rotating shaft which are in contact with the inner peripheral wall surface of the housing are reduced. Since the rigidity of the seal lip 112 that contacts the outer peripheral surface is low,
When the hydraulic pressure (arrow P) acts on the high-pressure oil chamber X and the high-pressure oil chamber X becomes a high pressure and a high pressure is applied to the seal lip, FIG.
As shown in FIG.
It causes a clinging to the inside of the body and causes problems such as abnormal wear of the seal lip.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a sealing device which prevents sticking and improves the performance of a seal lip. .

[0021]

In order to achieve the above object, in the present invention, a metal ring disposed in an annular gap between the housing and the shaft so as to be reciprocally movable in the axial direction, and an inner peripheral wall surface of the housing. A seal lip that slidably and slidably contacts
In the sealing device provided with, the metal ring has an outer peripheral portion extending in the axial direction and a flange portion extending in the inner diameter direction from the end portion of the outer peripheral portion, and the root of the seal lip is an inner peripheral wall surface of the housing. Is fixed to the metal ring so as to cover the surface of the outer peripheral portion opposite to, and a part of the surface extending from the tip of the seal lip toward the root covering the outer peripheral portion extends the root surface of the seal lip in the axial direction. It is characterized in that it enters the inner diameter side of the surface.

Since a part of the surface extending from the tip of the seal lip toward the root covering the outer peripheral portion enters the inner diameter side of the surface extending the axial direction of the root surface of the seal lip, a high pressure is applied to the seal lip. Even if such a problem occurs, the contact area between the seal lip and the inner peripheral wall surface of the housing can be reduced, and sticking can be prevented.

Further, in a sealing device provided with a metal ring disposed in the annular gap between the housing and the shaft so as to reciprocate in the axial direction, and a seal lip slidably sealingly contacting an outer peripheral wall surface of the shaft, The metal ring has an outer peripheral portion extending in the axial direction and a flange portion extending in the inner diameter direction from the end portion of the outer peripheral portion, and the root of the seal lip is formed on the metal ring so as to cover the end surface of the flange portion. A part of the surface fixed from the tip of the seal lip toward the root covering the end surface of the flange portion is located outside the surface of the root surface of the seal lip extending in the axial direction. To do.

A part of the surface extending from the tip of the seal lip toward the root covering the end surface of the flange portion is located on the outer diameter side of the surface extending in the axial direction of the root surface of the seal lip, whereby the seal is formed. Even if a high pressure is applied to the lip, the contact area between the seal lip and the outer peripheral surface of the shaft can be reduced, and sticking can be prevented.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions of the components described in this embodiment,
Unless otherwise specified, the material, the shape, the relative arrangement, and the like are not intended to limit the scope of the present invention thereto.

A sealing device according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a half sectional view of a bonded piston seal 1 as a sealing device according to an embodiment of the present invention.

The bonded piston seal 1 is, for example,
It is used to reduce the influence of centrifugal oil pressure acting on a hydraulic piston used in an automatic transmission for automobiles such as CVT.

The structure of the gear shift portion of the automatic transmission to which the bonded piston seal 1 is applied is substantially the same as the structure described in the above-mentioned prior art, and therefore its detailed description is omitted here. However, in order to facilitate understanding of the present embodiment, the same members as those in the conventional configuration shown in FIG. 4 will be described using the same member numbers in the following description.

(First Embodiment) The piston member 2 of the bonded piston seal 1 shown in FIG. 1 is composed of a metal ring 14 and an elastic body 11, and the metal ring 14 presses a metal plate material. The outer peripheral portion 14a is formed by processing or the like and extends in the axial direction, and the flange portion 14b extending in the inner diameter direction from the end portion of the outer peripheral portion on the fluid to be sealed side.

The elastic body 11 is a high pressure oil chamber X of the metal ring 14.
Side surface and outer peripheral portion 14a are formed by fixing rubber or the like to the metal ring 14 by baking or bonding so as to cover the surface facing the housing 100, and slidably seal the inner peripheral wall surface of the housing 100. And a sealing lip 11b slidably sealingly contacting the outer peripheral wall surface of the rotating shaft 101.

The root of the seal lip 11a is a surface substantially parallel to the inner peripheral wall surface of the housing 100,
It is fixed to the metal ring 14 so as to cover the surface of the outer peripheral portion 14a facing the housing.

Then, as shown in FIG. 2A, a part 12a of the surface extending from the tip of the seal lip 11a toward the root covering the outer peripheral portion 14a of the metal ring 14 covers the outer peripheral portion 14a of the metal ring. The surface of the root of the seal lip is located inside the surface 13a extending in the axial direction.

FIG. 2B shows a shape in which the pressure is increased by the hydraulic pressure (arrow P) acting on the pressure chamber X and the seal lip 11a is deformed under the high pressure in the above structure. . In this way, on the surface extending from the tip of the seal lip 11a toward the root that covers the outer peripheral portion 14a of the metal ring 14, the surface inside the seal lip root that covers the outer peripheral portion 14a of the metal ring is extended inside the surface 13a. By providing the part 12a which is embedded, the area in which the seal lip 11a and the inner peripheral wall surface of the housing 100 are in contact can be reduced as compared with the conventional example FIG. You can

Further, the part 12a which has entered is the metal ring 1.
The length L3 of the minimum cross-sectional area of the root of the seal lip of the conventional example and the length L3 of the present embodiment are substantially lower than the surface of the elastic body 11 that covers the flange portion 14b of No. 4 and near the metal ring 14. The lengths L1 can be made equal, that is, the rigidity of the seal lip can be made equal to that of the conventional example, and the contact area can be reduced while ensuring the rigidity as compared with the conventional example. From the above, by making the seal lip such a shape, even if the seal lip has low rigidity used to meet the demand for low sliding resistance,
It is possible to prevent stickiness.

(Second Embodiment) In the first embodiment, the seal lip 11a is in contact with the inner peripheral wall surface of the housing 100, but in the present embodiment, the outer peripheral surface of the rotating shaft 101 is used. It is applied to the seal lip 11b that contacts the.

The base of the seal lip 11b is the rotary shaft 10.
It is fixed so as to cover the end surface 14c of the flange portion 14b of the metal ring 14, which is a surface that is substantially parallel to the outer peripheral surface of 1.

Then, as shown in FIG. 3A, from the tip of the seal lip 11b to the end surface 14 of the flange portion 14b.
A part 12b of the surface that faces the root covering c is located inside the inner diameter side of a surface 13b that axially extends the surface of the root of the seal lip that covers the end surface 14c of the flange portion.

FIG. 3 (b) shows a shape in which the pressure is increased by the hydraulic pressure (arrow P) acting on the pressure chamber X in the above-mentioned structure, and the seal lip 11b is deformed under high pressure. . In this way, from the tip of the seal lip 11b toward the root that covers the end surface 14c of the flange portion 14b, on the outer diameter side of the surface 13b that extends the axial surface of the root surface of the seal lip that covers the end surface 14c of the flange portion. By providing the recessed portion 12b, the area in contact with the outer peripheral surface of the rotating shaft 101 can be reduced, and sticking can be prevented.

The part 12b that has entered is the root of the seal lip 11b and is the flange portion 14 of the metal ring 14.
Since it is near b, the contact area can be reduced without changing the length L2 of the minimum cross-sectional area portion of the root of the seal lip, that is, the rigidity of the seal lip can be secured, and the low sliding resistance can be achieved. Even in the case of the seal lip having a low rigidity used to meet the demand, stickiness can be prevented.

In the above embodiment, the seal lip of the piston member of the bonded piston seal is described, but it goes without saying that the present invention can be applied to seal lips of other pressure resistant seal members in general.

[0041]

As described above, according to the present invention,
Even if a high pressure is applied to the seal lip, the contact area between the seal lip and the contacted body can be reduced, and sticking can be prevented.

[Brief description of drawings]

FIG. 1 is a half sectional view of a sealing device (bonded piston seal) according to an embodiment of the present invention.

2A is an enlarged view of a portion A of FIG. 1, and FIG. 2B is a cross-sectional view showing a sliding state of the portion A under high pressure.

3A is an enlarged view of a B part in FIG. 1, and FIG. 3B is a sectional view showing a sliding state of the B part under a high pressure.

FIG. 4 is a half sectional view of a conventional sealing device.

5A is an enlarged view of a portion A in FIG. 4, and FIG. 5B is a sectional view showing a sliding state (a solid contact) of the portion A under a high pressure.

[Explanation of symbols]

1 Bonded piston seal (sealing device) 2 Piston member 11 elastic body 11a, 11b Seal lip 14 Metal ring 14a Outer periphery of metal ring 14b Metal ring flange 14c End face of flange 100 housing 101 rotation axis X High pressure oil chamber Y oil chamber Z low pressure oil chamber

Claims (2)

[Claims] 1. A sealing device comprising a metal ring disposed in an annular gap between a housing and a shaft so as to reciprocate in the axial direction, and a seal lip slidably sealingly contacting an inner peripheral wall surface of the housing. The metal ring has an outer peripheral portion extending in the axial direction and a flange portion extending in the inner diameter direction from the end portion of the outer peripheral portion, and the root of the seal lip is the outer peripheral portion facing the inner peripheral wall surface of the housing. Is fixed to the metal ring so as to cover the surface of the seal lip, and a part of the surface extending from the tip of the seal lip toward the root covering the outer peripheral portion is located on the inner diameter side of the surface extending the axial direction of the root surface of the seal lip. Sealing device characterized by being embedded. 2. A sealing device comprising: a metal ring disposed in an annular gap between a housing and a shaft so as to reciprocate in the axial direction; and a seal lip slidably sealingly contacting an outer peripheral surface of the shaft. The metal ring has an outer peripheral portion extending in the axial direction and a flange portion extending in the inner diameter direction from the end portion of the outer peripheral portion, and the root of the seal lip is formed on the metal ring so as to cover the end surface of the flange portion. It is characterized in that a part of the surface fixed from the tip of the seal lip toward the root covering the end surface of the flange portion is located on the outer diameter side of the surface extending the axial direction of the root surface of the seal lip. Sealing device.