JP2005325995A - Piston - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piston which secures a width of contact which is brought into contact with a part to be extruded, and improves quality by making a U-shaped cross section part a separate type. <P>SOLUTION: The piston is provided with a piston body 12, a reinforcing ring 13, and an outer periphery seal lip 14a. The piston body has a clutch extruding part 12d which is provided so that it is brought into contact with a multiple disc clutch 4 on its surface. Then the reinforcing ring is engaged with the periphery of an outer periphery skirt part 12c of the piston body 12, and the outer periphery seal lip 14a, which is provided at a reinforcing ring 13, is brought into hermetic contact with an outer diameter surface of a piston-insertion hole 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a piston applied to, for example, an automatic transmission for automobiles.

  2. Description of the Related Art As an automatic transmission used in an automobile or the like, a technique is widely known in which a multi-plate clutch is controlled by a pressing force of a hydraulic piston that is moved by applying hydraulic pressure in a rotating state to perform shift control. .

  FIG. 4 is a half-sectional view of a schematic configuration for explaining a schematic configuration of a shift switching portion of the automatic transmission.

  As shown in FIG. 4, the inner peripheral surface of the housing 100 and the outer peripheral surface of the shaft 101 are fixed and sealed to each other, and an annular piston insertion hole 102 is formed.

  A multi-plate clutch 103 is provided inside the housing 100, and an annular piston member 104 is disposed in the piston insertion hole 102 so as to be movable in the axial direction.

  An annular spring retainer 105 that restricts axial movement is attached to the outer periphery of the shaft 101. The movement of the spring retainer is restricted by a stopper 106 provided on the shaft 101.

  A seal lip 111 is provided on the inner peripheral surface of the piston member 104 to seal the outer peripheral surface of the shaft 101, and an outer peripheral surface of the piston member 104 is provided on the inner peripheral surface to seal the inner peripheral surface of the housing 100. A sealing lip 112 is provided for sealing contact. Thus, the hydraulic chamber is formed by sealing the piston insertion hole 102 with the seal lips 111 and 112. These seal lips 111 and 112 are made of a rubber-like elastic body.

  In the above configuration, when oil pressure (arrow P) acts and the pressure rises, the piston member 104 strokes against the urging force of the spring 108 toward the spring retainer 105 (downward in the figure), and the outer periphery of the piston member 104 The multi-plate clutch 103 is pressed at the end (R portion) 104b of the U-shaped section 104a on the side. As a result, the clutch plate provided on the housing 100 side comes into 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.

In this manner, the piston member 104 receives the hydraulic pressure and moves in the axial direction, and functions as a so-called bonded piston seal in which the rubber-like elastic body 113 constituting the seal lips 111 and 112 is integrally formed with the base material. ing. Such a piston member is disclosed in Patent Document 1, for example.
Japanese Patent Laid-Open No. 11-351273 Japanese Patent Laid-Open No. 9-257058

By the way, in the piston member 104 as shown in FIG. 4, it is necessary to form a pressing surface between the outer peripheral surface of the shaft 101 and the inner peripheral surface of the housing 100 in the radial direction. A U-shaped section 104 a having a U-shaped cross-section is provided, and the R section 104 b of the U-shaped section 104 a presses the multi-plate clutch (pressed part) 103. Therefore, it is difficult to ensure a sufficient contact width for contacting the multi-plate clutch 103. (If the width of the U-shaped section is increased in the radial direction, it may interfere with the inner peripheral surface of the housing 100 and the retainer 105. Also, a flat surface should be provided at the tip of the U-shaped section. In this case, stress concentration may occur in the portion and the strength may be deteriorated.) For this reason, the contact pressure of the R portion 104b increases, and wear or wear during durability (due to long-term or long-time use) The deformation becomes large, and there is a possibility that a functional problem that a change in the clutch characteristic with time is caused by a change in surface pressure may occur.

  In addition, on the manufacturing side, there is a problem that the ring-making (manufacturing) difficulty of the U-shaped section 104a is high and the number of ring-making steps increases.

  Moreover, in terms of quality, the U-shaped cross section causes a large load on the material during sheet metal bending, and the R portion on the inner peripheral side of the U-shaped section 104a is likely to crack. There is. Furthermore, there is a problem that the R portion on the inner circumferential side of the U-shaped section 104a cannot be sufficiently inspected for appearance.

  In addition, an adhesive treatment for baking the rubber-like elastic body on the piston member 104 is necessary, but in order to ensure the adhesive strength of the adhesive, it is necessary to perform sufficient washing in the previous process. In particular, when the gap between the valleys (inner side) of the U-shaped section 104a is narrow, the cleaning becomes insufficient, so that the rubber-like elastic body is not sufficiently bonded, and peeling may occur. is there.

  Further, when the rubber-like elastic body must be poured into the valley (inner side) of the U-shaped section 104a, an excessive amount of the rubber-like elastic body is required, and the rubber-like elastic body does not flow well. There is a risk of molding defects.

  The present invention has been made to solve the above-described problems of the prior art, and ensures a contact width that comes into contact with the pressed portion, and further improves quality by making the U-shaped cross section a separation type. An object is to provide a piston.

In order to achieve the above object, in the piston according to the present invention,
It is provided in the annular hole so as to be movable in the axial direction, and extends in the radial direction, from the outer diameter end portion of the radial direction portion to the axial direction one side, and to the axial direction one side end portion of the axial direction portion A piston body having an outer diameter side radial portion extending from the outer diameter side to the outer diameter side;
A reinforcing member fitted to the outer periphery of the axial portion of the piston body;
A sealing member provided on the reinforcing member and sealingly contacting the outer peripheral surface of the annular hole;
It is characterized by providing.

  Thereby, when a piston moves to an axial direction, a to-be-pressed part can be pressed by low surface pressure with sufficient contact width by the outer diameter side radial direction part provided in the piston main body. Therefore, even when used for a long period of time or for a long period of time, it becomes possible to suppress wear and deformation as compared with the conventional case, and it is possible to suppress a change with time in the clutch characteristics due to a change in surface pressure. In addition, the length (width) of the outer diameter side radial direction portion may be appropriately set so as to have a contact width sufficient to press the pressed portion according to the specifications of the piston. Moreover, the occurrence of various problems due to the conventional U-shaped section can be suppressed by making the U-shaped section used in the conventional piston a separate type (separate).

  In the above configuration, it is also preferable that the reinforcing member is positioned on the outer diameter side radial direction portion of the piston main body and fitted over the entire area of the axial direction portion. In particular, the reinforcing member may be positioned on the end surface on the other axial side of the outer diameter side radial portion.

  Thus, by positioning the reinforcing member in contact with the outer radial side portion of the piston body, the sealing performance of the sealing member provided on the reinforcing member can be further stabilized, and the outer diameter side diameter can be further stabilized. The pressing force when the direction portion presses the pressed portion can be stabilized. In addition, since the strength of the fitting portion can be increased by fitting the reinforcing member over the entire area in the axial direction, the sealing performance of the sealing member provided on the reinforcing member can be stabilized.

  In the above configuration, when the piston main body moves to one side in the axial direction, the outer diameter side radial direction portion presses a pressed portion provided in the vicinity of the outer peripheral surface of the annular hole in a planar shape. Is also preferable.

Further, in the above-described configuration, the piston body further includes an inner circumferential side seal member that is in sealing contact with the inner circumferential surface of the annular hole,
It is also preferable that the seal member and the inner peripheral side seal member are integrally formed with the piston body into which the reinforcement member is fitted, after the reinforcement member is fitted into the piston body.

In the above configuration, the seal member is formed integrally with the reinforcing member,
It is also preferable that the reinforcing member is fitted into the piston body after the sealing member is integrally formed.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the piston which ensured the contact width which contacts a to-be-pressed part, and also implement | achieved the improvement of quality by making a cross-sectional U-shaped part into a separation type.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the scope to the following embodiments.

(Embodiment 1)
FIG. 1 is a half sectional view of a schematic configuration showing a piston 11 according to Embodiment 1 of the present invention. FIG. 2 is a half sectional view of a schematic configuration for explaining a schematic configuration of a shift switching unit to which the bonded piston seal 1 configured by the piston 11 according to Embodiment 1 of the present invention is applied.

  As shown in the figure, the shift switching portion is provided with a shaft 2 and a housing 3 provided on the outer peripheral side of the shaft 2 and having an approximately L-shaped inner cross section.

  The housing 3 has a radial portion 31 and a circular portion 32. A multi-plate clutch (pressed portion) 4 is accommodated on the inner peripheral side of the circular portion 32. The sealing device according to the present embodiment may be used as a brake plate for a brake ON / OFF device.

  An annular piston insertion hole (annular hole) 5 is formed between the inner peripheral surface of the circular portion 32 and the outer peripheral surface of the shaft 2, and the piston 11 extends in the axial direction in the piston insertion hole 5. It is inserted freely. The inner peripheral surface of the circular portion 32 can also be referred to as the outer peripheral surface of the piston insertion hole 5, and the outer peripheral surface of the shaft 2 can also be referred to as the inner peripheral surface of the piston insertion hole 5.

  The piston 11 includes a piston main body 12, a reinforcing ring 13, and a seal main body 14 made of a rubber-like elastic body.

  The piston main body 12 is a metal ring of a thin steel plate (for example, SAPH440), and has a washer-like end wall 12a facing the end face of the radial portion 31 of the housing 3 and an outer diameter side from the outer diameter end of the end wall 12a. An inclined portion 12b extending obliquely toward the axial multi-plate clutch 4 side, an outer peripheral skirt portion 12c extending from the outer diameter end portion of the inclined portion 12b toward the axial multi-plate clutch 4 side, and an axis of the outer peripheral skirt portion 12c A clutch pressing portion 12d extending from the end portion on the directional multi-plate clutch 4 side to the outer diameter side, and an inner peripheral skirt portion 12e extending from the inner diameter end portion of the end wall 12a to the inner diameter direction and toward the axial multi-plate clutch 4 side. Has been. The piston main body 12 is formed by mold forming (for example, press molding).

  Here, the outer peripheral skirt portion 12c constitutes an axial portion according to the present invention, and the end wall 12a and the inclined portion 12b constitute a radial portion according to the present invention. Further, the clutch pressing portion 12d constitutes an outer diameter side radial direction portion according to the present invention, and is provided so as to contact the multi-plate clutch 4 in a planar shape.

  The reinforcing ring 13 includes an axial part 13a and a radial part 13b extending from the end of the axial part 13a on the radial part 31 side of the housing 3 to the outer diameter side.

  The reinforcing ring 13 is fitted and attached to the piston main body 12 by fitting the axial direction portion 13 a to the outer periphery of the outer peripheral skirt portion 12 c of the piston main body 12. After the reinforcing ring 13 is fitted and attached to the piston main body 12, the seal main body 14 is baked (integrally molded) on the reinforcing ring 13 and the piston main body 12 in the axial direction and on the radial portion 31 side of the housing 3. ) Here, the reinforcing ring 13 constitutes a reinforcing member according to the present invention. The reinforcing ring 13 may be attached to the piston body 12 by welding, for example.

  The seal body 14 includes an outer peripheral seal lip 14 a that is in slidable sealing contact with the inner peripheral surface of the circular portion 32, and an inner peripheral seal lip 14 b that is slidably sealed in contact with the outer peripheral surface of the shaft 2. Here, the outer peripheral seal lip 14a constitutes a seal member according to the present invention, and the inner peripheral seal lip 14b constitutes an inner peripheral side seal member according to the present invention.

  The outer peripheral seal lip 14a extends from the outer diameter end of the radial portion 13b of the reinforcing ring 13 to the outer diameter side and inclines toward the radial portion 31 of the housing 3, and the inner peripheral seal lip 14b The inner circumferential skirt portion 12e extends at an inner diameter side and inclines toward the radial direction portion 31 side of the housing 3.

  In this manner, the pressure chamber X is formed between the piston 11 and the housing 3 via the outer peripheral seal lip 14a and the inner peripheral seal lip 14b.

  A spring retainer 8 is provided on the outer peripheral side of the shaft 2 facing the piston 11 as an annular restricting member that restricts axial movement. The spring retainer 8 is a metal ring of a thin steel plate (for example, SAPH440), and has an inner diameter that is detachable with respect to the shaft 2. The spring retainer 8 is moved axially by the stopper 9, specifically, away from the piston 11. It is regulated.

  The outer diameter of the spring retainer 8 is smaller than the inner diameter of the outer peripheral skirt portion 12 c of the piston 11.

Between the spring retainer 8 and the piston 11, a plurality of springs 10 are provided in the circumferential direction as urging means for urging the piston 11 away from the spring retainer 8. The shaft 2 is provided with a hydraulic pressure supply passage 22 communicating with the pressure chamber X.

  In the above configuration, when the line pressure does not act on the pressure chamber X, the biasing force of the spring 10 is applied to the piston member 11, so that the stopper 14 c (positioning projection) is the radial portion of the housing 3. By contacting 31, the piston 11 is stationary.

  When the hydraulic pressure P acts on the pressure chamber X via the hydraulic pressure supply passage 22 of the shaft 2 and the pressure rises, the piston member 11 moves to the axial multi-plate clutch 4 side against the biasing force of the spring 10. The multi-plate clutch 4 is pushed by the clutch pressing portion 12d of the piston 11 to transmit power.

  When releasing the power transmission, the pressure supply of the pressure chamber X is turned off, and the piston 11 is moved to the radial portion 31 side of the axial housing 3 by the urging force of the spring 10. As a result, the piston 11 returns to the original position.

  As described above, in the present embodiment, the clutch pressing portion 12d is provided so as to come into contact with the multi-plate clutch 4 in a planar shape, so that the R portion of the U-shaped section in the conventional piston is a multi-plate. It is possible to suppress an increase in contact pressure and a change in surface pressure as in the case of contact with the clutch.

  And since the axial direction part 13a of the reinforcement ring 13 provided separately from the piston main body 12 is fitted to the outer peripheral skirt part 12c of the piston main body 12, the strength of the clutch pressing part 12d can be increased. Further, it is possible to more effectively suppress the contact pressure from increasing and the change in surface pressure from occurring.

  Furthermore, since the strength of the clutch pressing portion 12d can be increased, the size of the flat portion of the clutch pressing portion 12d can be increased, resulting in an increase in contact pressure and a change in surface pressure. Can be more effectively suppressed.

  And since it can suppress that a contact pressure becomes high, it can suppress that wear and a deformation | transformation become large by a long-term use for a long time. Moreover, since it can suppress that a surface pressure change arises, the temporal change of the clutch characteristic which arises by a surface pressure change can be suppressed. Therefore, it is possible to suppress the occurrence of functional problems that have been a concern.

  Moreover, since the piston 11 does not include a conventional U-shaped section that is difficult to produce a ring as in the prior art, there has been a concern that the number of processes for producing a ring has increased. It does not occur that the R portion of the U-shaped portion is easily cracked and that the appearance inspection of the R portion of the U-shaped cross section cannot be sufficiently performed. And by suppressing the increase in the number of steps in the ring production, it is possible to improve work efficiency and reduce costs.

  Further, since the piston 11 does not have a narrow gap that exists in the U-shaped section as in the prior art, the piston 11 can be sufficiently washed to ensure the adhesive strength of the adhesive. Therefore, it is possible to suppress the occurrence of peeling due to insufficient adhesion of the rubber-like elastic body.

Further, since the piston 11 does not have a U-shaped section, the rubber-like elastic body is not poured into the valley portion of the U-shaped section, and an excessive amount of rubber-like elasticity as in the prior art. The body is not what you need. Further, since the rubber-like elastic body is not poured into the concave portion such as the valley portion of the U-shaped section, it is possible to prevent the rubber-like elastic body from flowing well and causing molding defects.

  The axial portion 13 a of the reinforcing ring 13 provided separately from the piston body 12 is positioned by the clutch pressing portion 12 d of the piston body 12. Thereby, since the relative position (how much it is made to fit) when fitting the reinforcement ring 13 with the piston main body 12 can be determined easily, workability | operativity can be improved. Further, the sealing performance of the outer peripheral seal lip 14a can be further stabilized by bringing the axial portion 13a of the reinforcing ring 13 into contact with the clutch pressing portion 12d of the piston main body 12.

  Furthermore, the pressing force when the piston 11 presses the multi-plate clutch 4 can be stabilized by bringing the axial portion 13 a of the reinforcing ring 13 into contact with the clutch pressing portion 12 d of the piston main body 12. Therefore, the clutch pressing portion 12d comes into contact with the multi-plate clutch 4 in a more stable manner, and more effectively suppresses the contact pressure from being increased or the contact pressure from being changed. Can do. As a result, the operation of the automatic transmission can be further stabilized.

  In addition, when the seal lip is provided in the outer peripheral skirt portion in the prior art, when the piston 11 moves in the axial direction, the sealing performance of the seal lip is deteriorated due to the behavior of the outer peripheral skirt portion due to deformation caused by the movement. There is concern about becoming stable. In the present embodiment, the axial direction portion 13a and the outer peripheral skirt portion 12c are fitted by fitting the axial portion 13a of the reinforcing ring 13 provided separately from the piston main body 12 to the outer peripheral skirt portion 12c of the piston main body 12. The strength of the fitting portion can be increased. Therefore, the sealing performance of the outer peripheral seal lip 14a provided on the reinforcing ring 13 can be stabilized.

  Further, the length of the fitting portion between the axial direction portion 13a of the reinforcing ring 13 provided separately from the piston main body 12 and the outer peripheral skirt portion 12c of the piston main body 12 is made longer, so that the multi-plate clutch 4 It is possible to increase the strength of the clutch pressing portion 12d that contacts the surface and to stabilize the sealing performance of the outer peripheral seal lip 14a.

(Embodiment 2)
FIG. 3 is a schematic half sectional view of the piston 21 according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected about the component similar to Embodiment 1 mentioned above, and the description is abbreviate | omitted. Here, in the piston 21, as shown in FIG. 3, a stopper (positioning projection) 12 f is provided on the end wall 12 a to bring the piston 21 into a stationary state by contacting the radial portion 31 of the housing 3. Yes.

  In the first embodiment, the reinforcing ring 13 is fitted into the piston body 12 and then the seal body 14 is integrally formed. However, in the present embodiment, the outer peripheral seal lip 14a is integrally formed with the reinforcing ring 13. After the molding, the reinforcing ring 13 in which the outer peripheral seal lip 14a is integrally molded is fitted to the piston body 12.

  In the present embodiment, since the outer peripheral seal lip 14a is integrally formed with the reinforcing ring 13 and then fitted to the piston body 12, the seal lip can be configured with a smaller amount of rubber-like elastic body. Further, as shown in the figure, in the axial portion 13a of the reinforcing ring 13, the fitting portion between the reinforcing ring 13 and the piston body 12 is stabilized by molding the fitting portion with the piston body 12 with a rubber-like elastic body. In addition, it is not necessary to strictly limit the dimensional tolerance like fitting between metal rings.

  Here, the inner peripheral seal lip 14b is preferably formed integrally with the piston main body 12. However, the means for sealing the annular gap between the piston main body 12 and the outer peripheral surface of the shaft 2 is not limited to the inner peripheral seal lip 14b. Absent. For example, an O-ring is provided on the outer peripheral surface (groove) of the shaft 2, and the O-ring is slidable on an axial portion (a portion provided substantially linearly in the axial direction) provided on the inner peripheral skirt portion 12e. It may be configured to be brought into hermetic contact. In this case, since it is not necessary to integrally mold the rubber-like elastic body on the piston body 12, the manufacturing process can be reduced and the cost can be reduced.

1 is a schematic half sectional view showing a piston according to a first embodiment of the present invention. FIG. 2 is a half sectional view of a schematic configuration for explaining a schematic configuration of a shift switching unit to which a bonded piston seal configured by a piston according to Embodiment 1 of the present invention is applied. FIG. 3 is a schematic half sectional view showing a piston according to Embodiment 2 of the present invention. FIG. 4 is a schematic configuration diagram of a shift switching unit to which a piston according to the prior art is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bonded piston seal 11, 21 Piston 12 Piston main body 12a End wall 12b Inclined part 12c Outer peripheral skirt part 12d Clutch press part 12e Inner peripheral skirt part 12f Stopper (positioning equidistant projection)
13 Reinforcement ring 13a Axial portion 13b Radial portion 14 Seal body 14a Outer peripheral seal lip 14b Inner peripheral seal lip 14c Stopper (positioning equidistant protrusion)
2 shaft 22 hydraulic supply passage 3 housing 31 radial portion 32 circular portion 4 multi-plate clutch 5 piston insertion hole 8 spring retainer 9 stopper (snap ring)
10 Spring

Claims (5)

It is provided in the annular hole so as to be movable in the axial direction, and extends in the radial direction, from the outer diameter end portion of the radial direction portion to the axial direction one side, and to the axial direction one side end portion of the axial direction portion A piston body having an outer diameter side radial portion extending from the outer diameter side to the outer diameter side;
A reinforcing member fitted to the outer periphery of the axial portion of the piston body;
A sealing member provided on the reinforcing member and sealingly contacting the outer peripheral surface of the annular hole;
A piston comprising:   2. The piston according to claim 1, wherein the reinforcing member is positioned on the outer diameter side radial direction portion of the piston main body and is fitted over the entire area of the axial direction portion.   The said outer diameter side radial direction part presses the to-be-pressed part provided in the outer peripheral surface vicinity of the said annular hole planarly when the said piston main body moves to the axial direction one side. Or the piston according to 2; An inner circumferential side sealing member provided on the piston main body and sealingly contacting the inner circumferential surface of the annular hole;
The said sealing member and the said inner peripheral side sealing member are integrally molded by the said piston main body by which the said reinforcement member was fitted, after the said reinforcement member was fitted by the said piston main body. The piston according to any one of 1 to 3. The seal member is formed integrally with the reinforcing member,
The piston according to any one of claims 1 to 3, wherein the reinforcing member is fitted into the piston main body after the sealing member is integrally formed.

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