JP2005265073A - Piston device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a structure capable of preventing drop of pressure resistance and durability by securing a predetermined stiffness of a piston seal 13 irrespective of size of piston main body 11 and a seal diameter of the piston seal 13 formed as one piece with the same. <P>SOLUTION: The piston seal 13 made of rubber like elastic material is formed as one piece with the piston main body 11. An attachment ring 12 is fixed on the piston main body 11 by press fitting or the like, and a base part 13b of the piston ring 13 is connected to both of the piston main body 11 and the attachment ring 12. An end part of the attachment ring 12 reaches a root of a seal lip 13a of the piston seal 13. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a piston device that integrally has a piston seal, such as a clutch piston that is mounted on an automatic transmission of an automobile and performs a clutch switching operation.

In some automatic transmissions of automobiles, a clutch piston that operates in a cylinder by hydraulic pressure causes the drive plate on the drive shaft side and the driven plate on the driven shaft side to contact and separate from each other, thereby switching the clutch. In this clutch piston, for example, as disclosed in Patent Document 1 below, a piston seal made of a rubber-like elastic material is integrally formed.
Japanese Patent Laid-Open No. 9-210088

  FIG. 4 is a half sectional view showing a conventional piston device (clutch piston) described in Patent Document 1 cut along a plane passing through the axis O together with a part of the automatic transmission. That is, the clutch piston 101 is displaced downward in the figure against the urging force of the return spring 105 supported by the canceller 104 when the oil chamber 103 between the clutch piston 102 and the clutch cylinder 102 is pressurized. The pressing portion formed at the lower end of the outer peripheral cylinder portion 101a presses the drive plate 106a of the multi-plate clutch 106 against the driven plate 106b to frictionally engage the driving torque of the drive shaft with the clutch cylinder 102, the multi-plate clutch 106, and It is transmitted to the driven shaft via the clutch hub 107.

By the way, the clutch piston 101 is provided integrally with the outer peripheral portion thereof, and the seal diameter d ₁ of the piston seal 108 that is in close contact with the inner peripheral surface of the outer peripheral cylindrical portion 102a of the clutch cylinder 102 (the inner diameter of the outer peripheral cylindrical portion 102a of the cylinder 102). ), The position of the pressing portion of the outer peripheral cylindrical portion 101 a of the clutch piston 101 with respect to the multi-plate clutch 106, and the inner peripheral surface of the outer peripheral cylindrical portion 101 a of the clutch piston 101 provided integrally with the outer periphery of the canceller 104 that supports the spring 105. The seal diameter d ₂ of the canceller seal 109 that is in close contact with the inner diameter of the canceller seal 109 (the inner diameter of the outer peripheral cylinder portion 101a of the clutch piston 101) and the like are determined by the layout of the peripheral parts, the required performance, and the like. For this reason, depending on the positional relationship between the multi-plate clutch 106 and the clutch piston 101, the difference between the seal diameters d ₁ and d ₂ may be large. In such a case, the outer cylinder portion 101a of the clutch piston 101 This is dealt with by thickening the rubber layer 108a, on which the piston seal 108 is formed, in the radial direction.

  However, if the rubber layer 108 a on which the piston seal 108 is formed is thickened in the radial direction, the deformation of the piston seal 108 due to the hydraulic pressure introduced into the oil chamber 103 becomes large, and the inner periphery of the outer peripheral cylindrical portion 102 a of the cylinder 102 is increased. Problems such as early wear of the piston seal 108 due to an increase in the contact area with the surface and the contact load, and a decrease in pressure resistance and durability of the piston seal 108 due to spot wear are caused.

  The present invention has been made in view of the above points, and the technical problem thereof is that the piston seal can be used regardless of the size of the piston body and the seal diameter of the piston seal formed integrally therewith. It is intended to have a structure that can prevent early wear due to increase in contact area and contact load, and deterioration in pressure resistance and durability.

  As a means for effectively solving the above-mentioned technical problem, the piston device according to the invention of claim 1 is a piston device in which a piston seal made of a rubber-like elastic material is integrally formed on a piston body. An attachment ring is fixed to the main body, the piston seal is joined to both the piston main body and the attachment ring, and an end portion of the attachment ring extends to a base of a seal lip in the piston seal.

  According to the piston device of the first aspect of the present invention, a part of the rubber layer at the base of the piston seal is replaced with an attached ring having a higher rigidity, and one end thereof is at the root of the seal lip of the piston seal. Therefore, regardless of the size of the piston body and the seal diameter of the piston seal formed integrally with it, the required rigidity of the piston seal is ensured, and premature wear and erosion due to the solid contact of the seal lip of the piston seal Abrasion can be prevented and pressure resistance and durability can be maintained.

  Hereinafter, a preferred embodiment of a piston device according to the present invention will be described with reference to the drawings. First, FIG. 1 is a half sectional view showing an embodiment in which a piston device of the present invention is applied to a clutch piston 1 of an automatic transmission of an automobile, cut along a plane passing through an axis O together with a part of the automatic transmission. .

  That is, the clutch piston 1 corresponds to the piston device according to claim 1, and includes a piston body 11, an attachment ring 12 fixed to the piston body 11, and both the piston body 11 and the attachment ring 12. And a piston seal 13 integrally formed on the outer peripheral portion thereof.

  The piston body 11 is manufactured by punching and stamping a metal plate, and has an inner cylinder part 11a, a flange part 11b developed from one end thereof in a radial direction, and an outer periphery opposite to the inner cylinder part 11a. An intermediate tube portion 11c extending to the side, an end plate portion 11d extending in the radial direction from the end portion, an outer tube portion 11e extending from the outer periphery in the same direction as the intermediate tube portion 11c, and a tip of the outer tube portion 11e It consists of a hook-shaped clutch pressing portion 11f bent to the outer periphery. The attachment ring 12 is manufactured by pressing a metal plate or cutting a metal pipe, and is press-fitted to the outer peripheral surface of the outer cylinder portion 11e of the piston body 11 with an appropriate tightening margin.

  The piston seal 13 is made of a rubber-like elastic material, and has a seal lip 13a facing away from the multi-plate clutch 5 described later, and its base portion 13b is external to the end plate portion 11d of the piston body 11. The outer surface of the bent portion to the cylindrical portion 11e and the attached ring 12 press-fitted to the outer cylindrical portion 11e are integrally vulcanized and bonded. One end of the attachment ring 12 in the axial direction reaches the root portion of the seal lip 13 a of the piston seal 13.

  That is, the piston seal 13 is set in a predetermined rubber vulcanization molding die by setting the piston main body 11 in which the attachment ring 12 is press-fitted into the outer cylinder portion 11e and the vulcanizing adhesive is applied in advance. An unvulcanized rubber material is filled in an annular cavity defined between the piston body 11 and the attached ring 12 and the inner surface of the mold by tightening, and heated and pressurized simultaneously with vulcanization molding. The piston body 11 and the attached ring 12 are vulcanized and bonded.

  Reference numeral 2 is a clutch cylinder. The clutch cylinder 2 accommodates the clutch piston 1 so as to be axially displaceable, and is formed in an inner surface shape substantially similar to the piston main body 11, and the inner peripheral end is coupled and fixed to the drive shaft 3 side. It is provided integrally. And the inner cylinder part 11a of the piston main body 11 (clutch piston 1) is extrapolated to the drive shaft 3 side through an O-ring 31 made of a rubber-like elastic material so as to be movable in the axial direction. The outer periphery of the tip of the seal lip 13a is slidably in close contact with the inner peripheral surface 2a of the outer peripheral portion of the clutch cylinder 2. A plurality of lubricating grooves extending in the circumferential direction are formed on the sliding surface of the seal lip 13a with the clutch cylinder 2.

  Reference numeral 4 is a clutch hub coupled to a driven shaft (not shown), and reference numeral 5 is a multi-plate clutch. The multi-plate clutch 5 includes a plurality of drive plates 51 that are axially movable on the inner periphery of the clutch housing cylinder 2b of the clutch cylinder 2 and locked in a non-rotating state, and are axially movable and non-rotating on the clutch hub 4. A plurality of driven plates 52 locked in a state are arranged alternately in the axial direction and have a structure in which they are prevented from being detached by a retainer (not shown).

  Reference numeral 6 is a return spring that urges the clutch piston 1 away from the multi-plate clutch 5. The return spring 6 is a coil spring and is compressed between a canceller 7 fixed to the drive shaft 3 via a stop ring 71 and the clutch piston 1 in the circumferential direction. Has been placed. Reference numerals 61 and 62 are spring holders that hold both ends of the return spring 6.

  Specifically, the canceller 7 is manufactured by punching and press-molding a metal plate, from the inner peripheral flange portion 7a and the outer periphery thereof to the outer peripheral position of the intermediate cylinder portion 11c in the piston main body 11 of the clutch piston 1. An intermediate cylindrical portion 7b extending toward the outer peripheral portion, and an outer peripheral flange portion 7c that expands from the end portion toward the outer peripheral side and is opposed to the inner peripheral surface of the outer cylindrical portion 11e in the piston main body 11 in close proximity. A canceller seal 72 made of a rubber-like elastic material is integrally formed at the outer peripheral end portion of the outer peripheral flange portion 7c, and the outer periphery of the seal lip 72a facing away from the multi-plate clutch 5 is in the piston main body 11. The outer cylindrical portion 11e is slidably in close contact with the inner peripheral surface.

  In the above configuration, working oil pressure is introduced through an oil passage (not shown) into an oil chamber A defined between the inner surface of the clutch cylinder 2 and the clutch piston 1 and sealed by the O-ring 31 and the piston seal 13. When the oil chamber B defined between the clutch piston 1 and the canceller 7 and sealed by the canceller seal 72 is opened through another oil passage (not shown), the clutch piston 1 compresses the return spring 6 and moves downward in FIG. The clutch pressing portion 11f in the piston main body 11 presses the drive plate 51 in the multi-plate clutch 5 against the driven plate 52 to cause frictional engagement. Therefore, the multi-plate clutch 5 is in a connected state, and the drive torque of the drive shaft 3 is transmitted from the clutch cylinder 2 to the driven shaft (not shown) via the multi-plate clutch 5 and the clutch hub 4.

  Further, when the hydraulic pressure in the oil chamber A is released and hydraulic oil is supplied to the oil chamber B, the clutch piston 1 reduces the volume of the oil chamber A due to the repulsion of the compressed return spring 6 in FIG. Since it is displaced upward and the pressure on the drive plate 51 is released, the multi-plate clutch 5 is cut off, and transmission of drive torque from the drive shaft 3 to the driven shaft is cut off.

Here, the clutch piston 1 is designed so that the inner diameter 2a of the outer peripheral portion of the clutch cylinder 2 to which the piston seal 13 is in close contact, that is, the seal diameter d13 of the piston seal ₁₃ and the piston main body 11 to which the canceller seal 72 is in close contact. the inner diameter of the outer tubular portion 11e, that is, become a relatively large difference between the sealing diameter d ₇₂ of canceller seal 72. Therefore, the difference Δd between the sealing diameter d ₁₃ of the outer diameter and the piston seal 13 of the outer cylindrical portion 11e is also made large.

However, according to this embodiment, since the attachment ring 12 is fitted on the outer peripheral surface of the outer cylinder portion 11 e of the piston body 11, the outer diameter of the attachment ring 12 is substantially equal to the piston seal 13. It becomes the backup diameter. In other words, a part of the rubber layer 13c extending from the base portion 13b of the piston seal 13 is replaced with an attachment ring 12 made of a sufficiently large metal having rigidity, and one end of the rubber layer 13c is connected to the piston seal 13. It reaches the base of the seal lip 13a. Thus, the piston seal 13, or by increasing the protruding length of the seal lip 13a in accordance with the difference Δd between the sealing diameter d ₁₃ of the outer diameter and the piston seal 13 of the outer tubular portion 11e of the piston body 11, rubber layer 13c It is not necessary to increase the thickness in the radial direction, and the required rigidity of the seal lip 13a and the base portion 13b is ensured.

  Accordingly, in order to displace the clutch piston 1 downward and bring the multi-plate clutch 5 into the connected state, when the oil chamber A is made high by introducing the hydraulic pressure, the oil pressure in the oil chamber A causes the piston seal 13 The seal lip 13a can be prevented from sticking to the inner peripheral surface 2a of the outer peripheral portion of the clutch cylinder 2, and as a result, premature wear of the piston seal 13 due to an increase in contact area and contact load, Generation | occurrence | production can be prevented and pressure resistance and durability can be maintained.

  Next, FIGS. 2 and 3 are half sectional views showing another embodiment in which the piston device according to the present invention is applied to the clutch piston 1 of the automatic transmission of an automobile, cut along a plane passing through the axis O. It is.

  The clutch piston 1 shown in FIG. 2 and FIG. 3 is joined to both the disc-shaped piston main body 11, the attached ring 12 fixed to the outer periphery thereof, and both the piston main body 11 and the attached ring 12. A piston seal 13 integrally formed on the outer peripheral portion and an inner peripheral seal 14 provided integrally on the inner peripheral portion of the piston main body 11 are provided. The clutch piston 1 according to this embodiment is basically displaced downward in the figure against the urging force of the return spring supported by the canceller by the hydraulic pressure introduced into the oil chamber, as in the embodiment of FIG. Then, the clutch pressing portion 11f presses the drive plate of the multi-plate clutch against the driven plate and frictionally engages it.

  The piston main body 11 is manufactured into a flat disk shape by punching and pressing a metal plate. The piston main body 11 has an inner peripheral flange portion 11g and an intermediate portion that is radially expanded on the outer periphery via an intermediate step portion 11h. It consists of a flange portion 11i and a hook-shaped clutch pressing portion 11f formed on the outer periphery of the flange portion 11i via an outer peripheral step portion 11j. The attachment ring 12 is also manufactured by punching and pressing a metal plate, and is press-fitted with an appropriate tightening margin to the outer peripheral surface of the outer peripheral step portion 11j which is a short cylindrical shape of the piston body 11. Yes.

  The attached ring 12 according to the embodiment of FIG. 2 has an inner peripheral edge press-fitted to the outer circumferential step portion 11j of the piston main body 11 and a radial direction portion 12a abutted against the clutch pressing portion 11f of the piston main body 11, and an outer periphery thereof. The clutch pressing portion 11f and the axial portion 12b bent to the opposite side have a substantially L-shaped cross section. Further, the attached ring 12 according to the embodiment of FIG. 3 includes an inner circumferential axial portion 12c press-fitted to the outer circumferential step portion 11j of the piston body 11, and a radial direction extending from one end thereof and contacting the clutch pressing portion 11f. It has a substantially U-shaped cross section having a portion 12d and an outer peripheral axial direction portion 12e bent from the outer periphery to the side opposite to the clutch pressing portion 11f.

  The piston seal 13 is made of a rubber-like elastic material and has a seal lip 13a facing the opposite side of the multi-plate clutch 5 of FIG. 1 described above, and its base 13b is the outer periphery of the piston body 11. Both the outer surface of the stepped portion 11j and the attached ring 12 press-fitted to the outer circumferential stepped portion 11j are integrally vulcanized and bonded. The axial portion 12 b of the attachment ring 12 according to the configuration of FIG. 2 or the outer peripheral axial direction portion 12 e of the attachment ring 12 according to the configuration of FIG. 3 reaches the root portion of the seal lip 13 a of the piston seal 13.

  On the other hand, the inner peripheral seal 14 is made of the same rubber-like elastic material as the piston seal 13, and is continuous with the piston seal 13 through the film portion 15, and the inner peripheral end of the inner peripheral flange portion 11 g in the piston main body 11. Is vulcanized and bonded. This inner peripheral seal 14 has a seal lip 14a facing the opposite side to the multi-plate clutch 5 shown in FIG. 1 described above, and like the O-ring 31 in the embodiment of FIG. The side is sealed.

  The piston seal 13 and the inner peripheral seal 14 are set in a predetermined rubber vulcanization molding die by setting the piston main body 11 in which the attached ring 12 is press-fitted into the outer peripheral step portion 11j and vulcanized adhesive is applied in advance. Then, an unvulcanized rubber material is filled in an annular cavity defined between the inner peripheral portion of the piston body 11 and the inner ring 12 and the inner surface of the mold by clamping. By pressing, it is vulcanized and bonded simultaneously with vulcanization molding.

  2 or 3, the axial portion 12b or the outer peripheral axial portion 12e of the attachment ring 12 fixed to the piston body 11 reaches the root portion of the seal lip 13a of the piston seal 13. The required rigidity of the seal lip 13a and the base portion 13b is ensured. Therefore, it is possible to prevent the seal lip 13a of the piston seal 13 from sticking to the inner peripheral surface of the outer peripheral portion of the clutch cylinder by the operating hydraulic pressure. As a result, the piston seal 13 of the piston seal 13 is increased due to an increase in contact area and contact load. It is possible to prevent pressure wear and durability by preventing the occurrence of premature wear and spot wear.

  In each of the above-described embodiments, the attachment ring 12 is fixed to the piston main body 11 by press fitting. However, the attachment ring 12 may be fixed to the piston main body 11 by means other than press fitting, such as welding or brazing. . Further, the sectional shape of the attachment ring 12 is appropriately determined in consideration of the size of the base portion 13b of the piston seal 13 and the like, and is not particularly limited to the illustrated one.

1 is a half cross-sectional view showing an embodiment in which a piston device according to the present invention is applied to a clutch piston of an automatic transmission of an automobile, cut along a plane passing through an axis O together with a part of the automatic transmission. FIG. 6 is a half sectional view showing another embodiment in which the piston device according to the present invention is applied to a clutch piston of an automatic transmission of an automobile, cut along a plane passing through an axis O. FIG. 6 is a half sectional view showing another embodiment in which the piston device according to the present invention is applied to a clutch piston of an automatic transmission of an automobile, cut along a plane passing through an axis O. FIG. 6 is a half sectional view showing a conventional piston device cut along a plane passing through an axis O together with a part of an automatic transmission.

Explanation of symbols

1 Clutch piston (piston device)
11 Piston body 12 Attached ring 13 Piston seals 13a, 14a Seal lip 14 Inner peripheral seal 15 Membrane 2 Clutch cylinder 3 Drive shaft 4 Clutch hub 5 Multi-plate clutch 6 Return spring 7 Canceller 71 Retaining ring 72 Canceller seal A, B Oil chamber

Claims (1)

  In the piston device (1) in which a piston seal (13) made of a rubber-like elastic material is integrally formed with the piston body (11), an attachment ring (12) is fixed to the piston body (11), and the piston seal (13) is joined to both the piston body (11) and the attachment ring (12), and the end of the attachment ring (12) extends to the base of the seal lip (13a) in the piston seal (13). A piston device characterized by that.

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