Piston seal

Abstract

To provide a piston seal which forms a sealed closed space between the piston seal and an annular groove part and reciprocates between a reference surface provided outside the groove part and a clutch member with a simple structure.SOLUTION: A first annular portion 30 forming a closed space 22 with the groove 12, and a second annular portion 40 arranged between the first annular portion 30 and the clutch member 14; And a second annular portion 40 including an intermediate portion 41 in contact with the first annular portion 30, a reference portion 42 capable of coming into contact with and separating from the protruding surface 11c, a clutch contact portion 43 in contact with the clutch member 14 when the reference portion 42 is separated from the protruding surface 11c, the clutch contact portion 43 being separated from the clutch member 14 when the reference portion 42 is in contact with the protruding surface 11c, and an outer edge portion 44 in contact with the biasing portion 15 at a position separated from the reference portion 42 and the clutch contact portion 43 in the radial direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a piston seal. [Background technology]

[0002] In actuators for automatic transmissions or continuously variable transmissions for vehicles such as automobiles, a sealing device having a piston seal as described in Patent Document 1 is employed to switch the operation of a clutch member on and off. The sealing device described in Patent Document 1 is arranged inside a housing so as to be able to reciprocate along the axis while facing the clutch member, and has an annular piston lip made of an elastic body that slides and seals against the inner circumferential surface of the housing along the axis, and is equipped with an annular piston seal that forms a piston hydraulic chamber together with the housing, and a biasing member that biases the piston seal toward the piston hydraulic chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-115689 Summary of the Invention [Problem to be solved by the invention]

[0004] As described in Patent Document 1, conventional piston seals have a structure formed by bending a single panel-like member. However, the positional relationship between the actuator's clutch member, the biasing member, and the reference surface that contacts the piston seal when the clutch member is off is not limited to the embodiment described in Patent Document 1 and can take a variety of patterns depending on the specifications of the actuator. Therefore, depending on the positional relationship between the clutch member, the biasing member, and the reference surface, conventional piston seals may not easily provide all of the functions required of a piston seal, such as sealing performance, durability, and contact with the clutch member and the biasing member, due to structural issues.

[0005] The present disclosure aims to provide a piston seal with a simple configuration that forms a sealed closed space between itself and an annular groove and moves back and forth between a reference surface provided outside the groove and a clutch member. [Means for solving the problem]

[0006] An aspect of the present disclosure is a piston seal that is reciprocable by a biasing portion between a reference surface provided on the outside of an annular groove portion provided around an axis, the reference surface opening toward a first direction along the axis, and a clutch member provided away from the reference surface on the first direction side, a first annular portion concentric with the groove portion and forming a sealed closed space between the groove portion and the first annular portion; a second annular portion disposed between the first annular portion and the clutch member and configured to move integrally with the first annular portion, a first contact portion that contacts the first annular portion; a second contact portion that can be brought into contact with and separated from the reference surface; a third contact portion that contacts the clutch member when the second contact portion is spaced apart from the reference surface, the third contact portion being spaced apart from the clutch member when the second contact portion is in contact with the reference surface; a fourth contact portion that contacts the biasing portion at a position radially spaced apart from the second contact portion and the third contact portion; and a second annular portion having A piston seal having: [Effects of the Invention]

[0007] According to the present disclosure, a piston seal can be provided with a simple configuration that forms a sealed closed space between itself and an annular groove and moves back and forth between a reference surface provided outside the groove and a clutch member. [Brief explanation of the drawings]

[0008] [Figure 1]FIG. 2 is a cross-sectional view of the piston seal and its surroundings of the actuator according to the embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the piston seal and its surroundings of the actuator according to the embodiment. [Figure 3] FIG. 2 is a cross-sectional view of the piston seal according to the embodiment. [Figure 4] FIG. 2 is a cross-sectional view of a first annular portion of the piston seal according to the embodiment. [Figure 5] FIG. 3 is a cross-sectional view of a second annular portion of the piston seal according to the embodiment. [Figure 6] FIG. 10 is a cross-sectional view showing an example of a piston seal according to a comparative embodiment. [Figure 7] FIG. 10 is a cross-sectional view showing an example of a piston seal according to a comparative embodiment. [Figure 8] FIG. 10 is a cross-sectional view of a modified example of the piston seal according to the embodiment. [Figure 9] FIG. 10 is a cross-sectional view of a modified example of the piston seal according to the embodiment. [Figure 10] FIG. 10 is a cross-sectional view of a modified example of the piston seal according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The drawings are not necessarily drawn to scale, and some features may be exaggerated or omitted. In the following description, the direction along the axial direction of the actuator is referred to as the X direction. The direction in which the piston seal approaches the clutch member along the axial direction is referred to as the +X direction. The direction in which the piston seal moves away from the clutch member along the axial direction is referred to as the -X direction. Furthermore, in the radial direction relative to the axial direction, the direction away from the central axis is referred to as the radially outward direction. In the radial direction relative to the axial direction, the direction toward the central axis is referred to as the radially inward direction.

[0010] A piston seal 20 according to the present disclosure is applied to a clutch piston mechanism of an actuator (not shown) for a vehicle such as an automobile. The actuator is, for example, an automatic transmission. The actuator may also be a continuously variable transmission. The actuator according to the embodiment is a non-rotating type. As shown in FIG. 1, the actuator according to the embodiment includes a housing portion 10, a clutch member 14, a biasing portion 15, and a piston seal 20.

[0011] The housing portion 10 is annular and formed around the X-axis (also referred to as the axis X). The housing portion 10 has a groove-like shape in which the piston seal 20 is fitted. The housing portion 10 has a central portion 11, a groove portion 12, and a port portion 10a.

[0012] The central portion 11 is formed around the X axis and has a cylindrical shape extending along the X direction. The central portion 11 has a base portion 11a and a protruding surface 11c. The base 11a is positioned radially so as to overlap a groove bottom 12a (described later). The central portion 11 protrudes from the base 11a in the +X direction. The +X direction is an example of a first direction. The protruding surface 11c is provided at a position away from the base portion 11a on the +X side and faces the +X direction. The protruding surface 11c is provided on the outside of a groove portion 12, which will be described later. The protruding surface 11c can come into contact with and separate from a reference portion 42 of the piston seal 20 in accordance with the operation of the piston seal 20, which will be described later. As a result, the protruding surface 11c functions as a reference position for the operation of the piston seal 20. The protruding surface 11c is an example of a reference surface.

[0013] The groove portion 12 is an annular groove provided around the central portion 11. That is, the groove portion 12 is provided outside the protruding surface 11c. The groove portion 12 is provided around the axis X. The groove portion 12 opens toward the +X side. The groove portion 12 has a groove bottom 12a, an outer peripheral wall 12b, and an inner peripheral wall 12c. The groove bottom 12a is an annular flat surface facing the +X side. The outer peripheral wall 12b is a wall-like shape that stands in the +X direction from the radially outer edge of the groove bottom 12a. In other words, the outer peripheral wall 12b is a groove wall that stands on the opposite side of the groove bottom 12a from the central portion 11. The outer peripheral wall 12b is an example of an outer groove wall. The inner peripheral wall 12c is made of a cylindrical side wall of the central portion 11. In other words, the inner peripheral wall 12c is a wall-like shape that stands in the +X direction from the radially inner edge of the groove bottom 12a.

[0014] The port portion 10a is a flow path provided in the groove bottom 12a. The port portion 10a is connected to a hydraulic oil tank (not shown). The actuator can supply and suck hydraulic oil H to the groove portion 12 via the port portion 10a. That is, the actuator can supply and suck hydraulic oil H to and from the closed space 22 (described later) via the port portion 10a. The hydraulic oil H is, for example, ATF (Automatic Transmission Fluid). The hydraulic oil H functions as a power source for power FH. The power FH is a force acting on the piston seal 20 in the +X direction. The hydraulic oil H is an example of a fluid that is supplied to or sucked into the closed space 22 via the port portion 10a.

[0015] The clutch member 14 operates the actuator in response to connection with the piston seal 20. The clutch member 14 is, for example, a multi-plate clutch. As shown in FIG. 1, the clutch member 14 is provided away from the housing portion 10 on the +X side. As shown in FIGS. 1 and 2, the clutch member 14 can be brought into contact with and separated from the piston seal 20 in response to the reciprocating motion of the piston seal 20. The clutch member 14 is an example of a connecting body. The clutch member 14 has a clutch plate 14a. The clutch plate 14a is a plate formed around the X-axis. At least a portion of the clutch plate 14a overlaps with the central portion 11 of the housing portion 10 when viewed in the axial direction. The clutch plate 14a overlaps with a portion of the groove bottom 12a of the groove portion 12 when viewed in the axial direction.

[0016] The biasing portion 15 biases the piston seal 20 toward the -X side. As shown in FIG. 1 , the biasing portion 15 is disposed at a position spaced apart radially outward from the clutch member 14. The biasing portion 15 has a retainer 16 and a spring portion 17.

[0017] As shown in FIG. 1 , the spring portion 17 is disposed on the same axial side (+X side) of the piston seal 20 as the clutch member 14. The spring portion 17 is, for example, a compression coil spring standing in the axial direction. The +X side end of the spring portion 17 is supported by a support means of an actuator (not shown). The spring portion 17 applies a biasing force FS to the piston seal 20. The biasing force FS is a force that acts on the piston seal 20 in the −X direction. The spring portion 17 is an example of a biasing means for the piston seal 20.

[0018] The retainer 16 is disposed between the piston seal 20 and the spring portion 17. The retainer 16 holds the end of the spring portion 17 on the -X side. As shown in FIG. 1, the retainer 16 is in contact with the piston seal 20. This allows the retainer 16 to transmit the biasing force FS from the spring portion 17 to the piston seal 20. As shown in FIGS. 1 and 2, the retainer 16 moves integrally with the piston seal 20 as the piston seal 20 reciprocates. The retainer 16 has a holding portion 16a and a protruding portion 16b.

[0019] The retaining portion 16a is plate-shaped and faces in the X direction. As shown in Fig. 1, the retaining portion 16a has a retaining means capable of retaining the -X side end of the spring portion 17. The retaining means is, for example, a protrusion that can fit into the inner diameter portion of the spring portion 17. The -X side surface of the retaining portion 16a is in surface contact with an outer edge portion 44 of the second annular portion 40, which will be described later.

[0020] The protruding portion 16b extends from the radially inner edge of the retaining portion 16a so as to protrude toward the -X side. Specifically, the protruding portion 16b extends toward a middle portion 41 (described later) of the second annular portion 40. In other words, the retainer 16 extends toward the middle portion 41. The protruding portion 16b is in surface contact with the middle portion 41.

[0021] <Piston Seal 20> As shown in FIGS. 1 and 2, the piston seal 20 is disposed between the housing portion 10 and the clutch member 14. The piston seal 20 is annular and concentric with the groove portion 12. The piston seal 20 is attached to the housing portion 10 so as to be movable in the axial direction. The piston seal 20 can reciprocate between the housing portion 10 and the clutch member 14 by power FH and biasing force FS. The piston seal 20 has a BPS (Bonded Piston Seal) structure. As shown in FIG. 3, the piston seal 20 has a first annular portion 30 and a second annular portion 40.

[0022] <First annular portion 30> 1 and 2, the first annular portion 30 is arranged to be received in the groove portion 12 of the housing portion 10. The first annular portion 30 is annular and concentric with the groove portion 12. As shown in FIG. 4, the first annular portion 30 has a main body portion 32 and a seal portion 34.

[0023] The main body 32 is in the form of a metal panel. The main body 32 preferably has a uniform thickness. As shown in FIG. 4, the main body 32 has a size that can be accommodated in the groove 12. The main body 32 is preferably formed from stainless steel, cold-rolled steel (e.g., SPCC, etc.), or hot-rolled steel (e.g., SPFH, SAFH, etc.). The main body 32 is formed by pressing and / or forging an annular, flat metal material having an inner periphery and an outer periphery. The cross section of the main body 32 is symmetrical about the X-axis. The main body 32 has an opposing portion 32a and a rib portion 32b. The facing portion 32a is annular and flat, facing the groove bottom 12a. The annular facing portion 32a has a central hole through which the central portion 11 of the housing portion 10 can pass. The rib portion 32b stands on the +X side from the outer periphery of the opposing portion 32a along the outer periphery wall 12b of the groove portion 12. The rib portion 32b is formed by bending the outer periphery by pressing and / or forging the metal material of the first annular portion 30 before processing. The cross section of the main body 32 on one side with the axis X as the center line is an L-shape formed by the opposing portion 32a and the rib portion 32b.

[0024] The seal portion 34 is made of an elastomer and is vulcanization-bonded to a portion of the main body portion 32 facing the groove bottom 12a. As shown in FIG. 4, the seal portion 34 is provided in a portion of the main body portion 32 facing the groove bottom 12a (-X side). The seal portion 34 further extends from the -X side to the +X side near the central hole of the main body portion 32. The seal portion 34 is annular and concentric with the groove portion 12. The seal portion 34 is preferably made of nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber (ACM), fluororubber (FKM), silicone rubber, or styrene butadiene rubber (SBR). The seal portion 34 has an outer lip portion 34b and an inner lip portion 34c. The outer lip portion 34b is a part of the outer edge of the seal portion 34 that faces the groove bottom 12a. The outer lip portion 34b is a protrusion formed on the outer edge of the seal portion 34. As shown in FIG. 1, when the piston seal 20 is installed in the housing portion 10, the outer lip portion 34b comes into contact with the outer peripheral wall 12b of the groove portion 12 and is compressively deformed. This allows the outer lip portion 34b to seal between the seal portion 34 and the outer peripheral wall 12b. The inner lip portion 34c is a part of the inner edge portion of the seal portion 34 that faces the groove bottom 12a. The inner lip portion 34c is a protrusion formed on the inner edge portion of the seal portion 34. As shown in FIG. 1, when the piston seal 20 is installed in the housing portion 10, the inner lip portion 34c comes into contact with the inner circumferential wall 12c of the groove portion 12 and is compressively deformed. As a result, the inner lip portion 34c forms a seal between the seal portion 34 and the inner circumferential wall 12c. When the piston seal 20 is mounted in the housing part 10, the seal part 34 is axially slidable relative to the housing part 10 (see FIGS. 1 and 2).

[0025] 1, when the piston seal 20 is attached to the housing portion 10, the first annular portion 30 having the seal portion 34 forms a closed space 22 between itself and the groove portion 12. The closed space 22 is sealed by the seal portion 34. The closed space 22 is filled with hydraulic oil H.

[0026] <Second annular portion 40> As shown in FIGS. 1 and 2 , the second annular portion 40 is disposed between the first annular portion 30 and the clutch member 14. The second annular portion 40 is in contact with the first annular portion 30 so as to be attached from the side opposite the groove 12 of the first annular portion 30. The first annular portion 30 and the second annular portion 40 move integrally with each other. That is, when the first annular portion 30 moves, the second annular portion 40 moves integrally with the first annular portion 30. The second annular portion 40 is annular and concentric with the first annular portion 30. The second annular portion 40 is a metal panel. The second annular portion 40 preferably has a uniform thickness. The second annular portion 40 is preferably formed from stainless steel, cold-rolled steel (e.g., SPCC, etc.), or hot-rolled steel (e.g., SPFH, SAFH, etc.). The second annular portion 40 is formed by pressing and / or forging an annular, flat metal material having an inner circumferential portion and an outer circumferential portion. The cross section of the second annular portion 40 is symmetrical about the X-axis. 5, the second annular portion 40 has an intermediate portion 41, a reference portion 42, a clutch contact portion 43, an outer edge portion 44, a bent portion 45, and a bent portion 46. In the second annular portion 40, the reference portion 42, the clutch contact portion 43, the bent portion 45, the intermediate portion 41, the bent portion 46, and the outer edge portion 44 are arranged in this order from the radially inner side to the radially outer side.

[0027] The intermediate portion 41 is provided between the outer edge portion 44 and the reference portion 42 and the clutch contact portion 43. The intermediate portion 41 is a flat plate extending in the radial direction. The intermediate portion 41 is in surface contact with the opposing portion 32a of the first annular portion 30 on the side opposite the groove portion 12 of the first annular portion 30. The intermediate portion 41 is a part of the first contact portion that contacts the first annular portion 30. The power FH is transmitted to the intermediate portion 41 from the first annular portion 30. The intermediate portion 41 is spaced radially outward from the clutch contact portion 43. The intermediate portion 41 is spaced radially outward from the reference portion 42. The intermediate portion 41 is in surface contact with the protruding portion 16b of the retainer 16. The intermediate portion 41 is part of a fourth contact portion that contacts the biasing portion 15. At least a portion of the biasing force FS is transmitted to the intermediate portion 41 from the biasing portion 15. The intermediate portion 41 is in surface contact with both the first annular portion 30 and the urging portion 15. In other words, the first contact portion that contacts the first annular portion 30 and the fourth contact portion that contacts the urging portion 15 overlap in the radial direction.

[0028] The reference portion 42 is provided radially inward of the intermediate portion 41. The reference portion 42 is provided on the side of the second annular portion 40 closest to the X-axis. The reference portion 42 is an inner edge portion of the annular metal material that forms the second annular portion 40. The reference portion 42 is a flat plate extending along the radial direction. The reference portion 42 is arranged on the side closer to the clutch member 14 (+X side) than the intermediate portion 41 in the X-axis direction. The reference portion 42 contacts the protruding surface 11c of the center portion 11 when the piston seal 20 is in a reference state, which will be described later. The reference portion 42 is an example of a second contact portion.

[0029] The clutch contact portion 43 is formed to extend radially outward from the reference portion 42. The clutch contact portion 43 is provided between the reference portion 42 and the intermediate portion 41. The clutch contact portion 43 is a flat plate extending along the radial direction. The clutch contact portion 43 is arranged on the side closer to the clutch portion 14 (+X side) of the reference portion 42 in the X-axis direction. The clutch contact portion 43 comes into contact with the clutch member 14 when the piston seal 20 is in a contact state described below. The clutch contact portion 43 is an example of a third contact portion.

[0030] The bent portion 45 connects the clutch contact portion 43 and the intermediate portion 41. The bent portion 45 extends in the axial direction from the end of the clutch contact portion 43 opposite the reference portion 42 toward the intermediate portion 41. The bent portion 45 has a thin-walled hollow cylindrical shape with the axis X as its center line. The bent portion 45 is formed by bending the portion between the clutch contact portion 43 and the intermediate portion 41 in the metal material of the second annular portion 40 before processing by pressing and / or forging. The bent portion 45 is an example of a connecting portion.

[0031] The outer edge portion 44 is provided on the side of the second annular portion 40 farthest from the X-axis. The outer edge portion 44 is a flat plate extending in the radial direction. The outer edge portion 44 is disposed on the side closer to the clutch member 14 (+X side) than the intermediate portion 41 in the X-axis direction. The outer edge portion 44 is disposed away from the rib portion 32b of the first annular portion 30 in the X-axis direction and closer to the clutch member 14. The outer edge portion 44 is disposed on the side farther from the clutch member 14 than the clutch contact portion 43 in the X-axis direction. The outer edge portion 44 is disposed on the radially opposite side of the intermediate portion 41 from the reference portion 42 and the clutch contact portion 43. In other words, the outer edge portion 44 is spaced radially outward from the reference portion 42 and the clutch contact portion 43. The outer edge portion 44 overlaps with the rib portion 32b when viewed radially. The outer edge portion 44 is in surface contact with a portion of the retaining portion 16a of the cage 16 facing the -X side. The outer edge portion 44 is a part of the fourth contact portion. At least a portion of the biasing force FS is transmitted to the outer edge portion 44 from the biasing portion 15.

[0032] The bent portion 46 connects the intermediate portion 41 and the outer edge portion 44. The bent portion 46 extends in the axial direction from the end of the intermediate portion 41 opposite the bent portion 45 toward the outer edge portion 44. The bent portion 46 has a thin-walled hollow cylindrical shape with the axis X as its center line. The bent portion 46 is formed by bending the portion between the intermediate portion 41 and the outer edge portion 44 of the metal material of the second annular portion 40 before processing by pressing and / or forging. The bent portion 46 contacts a portion of the rib portion 32b of the first annular portion 30 facing radially inward. In other words, the bent portion 46 contacts the rib portion 32b on the side opposite the groove portion 12 of the first annular portion 30. The bent portion 46 is part of the first contact portion. The second annular portion 40 is attached to the first annular portion 30 such that the bent portion 46 fits into the rib portion 32b.

[0033] A cross section of the second annular portion 40 on one side with the axis X as the center line includes a U-shaped cross section that stands parallel to the axis X. The U-shaped cross section is formed by an intermediate portion 41 and bent portions 45 and 46. The U-shaped cross section is open toward the +X side. The outer edge portion 44 extends radially outward from the radially outer open end of the U-shaped cross section. The clutch contact portion 43 extends radially inward from the radially inner open end of the U-shaped cross section. In other words, the U-shaped cross section protrudes toward the -X side with respect to the outer edge portion 44 and the clutch contact portion 43.

[0034] <Operation of the piston seal 20> Next, the operation of the piston seal 20 will be described. As shown in FIG. 1 , when the reference portion 42 of the piston seal 20 contacts the protruding surface 11c of the housing portion 10, the piston seal 20 and the biasing portion 15 are in a reference state. The closed space 22 of the piston seal 20 in the reference state is filled with a first amount of hydraulic oil H at a predetermined pressure. At this time, the hydraulic oil H in the closed space 22 applies a force FH to the first annular portion 30, pushing it toward the +X direction. In the piston seal 20 in the reference state, the force FH acts to balance the biasing force FS by the biasing portion 15 in the reference state. The value of the force FH acting on the piston seal 20 in the reference state (and the biasing force FS by the biasing portion 15 in the reference state) is an example of a first threshold value. That is, when the force FH is equal to or less than the first threshold value, the piston seal 20 contacts the protruding surface 11c at the reference portion 42, thereby entering the reference state. When the piston seal 20 is in the reference state, the piston seal 20 does not contact the clutch member 14. That is, when the reference portion 42 is in contact with the protruding surface 11c, the clutch contact portion 43 is separated on the −X side from the clutch member 14. At this time, the actuator is in a non-operating state.

[0035] When a user (not shown) performs an operation to activate an actuator that is in an inactive state, hydraulic oil H is supplied from the port portion 10a. When hydraulic oil H is supplied from the port portion 10a, the amount of hydraulic oil H in the closed space 22 formed between the piston seal 20 and the groove portion 12 in the reference state increases. As hydraulic oil H is supplied from the port portion 10a, the hydraulic oil H in the closed space 22 acts to push the first annular portion 30 toward the +X side relative to the reference state in order to maintain the pressure in the closed space 22 at a predetermined pressure value. In other words, as hydraulic oil H is supplied from the port portion 10a, the hydraulic oil H in the closed space 22 increases the power FH. Thereafter, as hydraulic oil H is further supplied from port 10a, the power FH exceeds the biasing force FS of biasing portion 15 in the reference state, and the first annular portion 30 and the second annular portion 40 (i.e., piston seal 20) move toward the +X side. Specifically, when the power FH is greater than the biasing force FS of biasing portion 15 in the reference state, reference portion 42 moves away from protruding surface 11c toward the +X side. At this time, as piston seal 20 moves toward the +X side, spring portion 17 of biasing portion 15 contracts. At this time, spring portion 17 contracts until the biasing force FS of biasing portion 15 increases to balance with the increased power FH. In this way, reference portion 42 can move toward and away from protruding surface 11c.

[0036] Thereafter, as hydraulic oil H is further supplied from the port portion 10a, the power FH further exceeds the biasing force FS of the biasing portion 15, and the piston seal 20 moves further toward the +X side, bringing the clutch contact portion 43 into contact with the clutch member 14 and entering a contact state (see FIG. 2). The closed space 22 of the piston seal 20 in the contact state is filled with a second amount of hydraulic oil H at a predetermined pressure value. The value of the power FH acting on the piston seal 20 in the contact state is greater than that in the reference state. The value of the power FH acting on the piston seal 20 in the contact state is an example of a second threshold value. That is, the piston seal 20 comes into contact with the clutch member 14 when the power FH is equal to or greater than the second threshold value. At this time, the actuator enters an actuated state.

[0037] When a user performs an operation to deactivate an actuator that is in an activated state, hydraulic oil H is sucked from the port portion 10a. When hydraulic oil H is sucked from the port portion 10a, the amount of hydraulic oil H in the closed space 22 formed between the piston seal 20 in contact with the groove portion 12 decreases. When the amount of hydraulic oil H in the closed space 22 decreases compared to when the piston seal 20 is in contact with the groove portion 12, the power FH decreases compared to when the piston seal 20 is in contact with the protruding surface 11c of the center portion 11 and becomes smaller than the biasing force FS in the contact state. As a result, the piston seal 20 in contact with the protruding surface 11c of the center portion 11 moves toward the -X side until it contacts the protruding surface 11c of the center portion 11 (see FIG. 1). In other words, when the power FH is smaller than the biasing force FS by the biasing portion 15 in the contact state, the clutch contact portion 43 moves away from the clutch member 14 toward the -X side.

[0038] (Action and effect) Next, the operation and effect of the piston seal 20 of the embodiment will be described. In this description, piston seal G20 and piston seal H20 will be described as comparative examples to the embodiment, with reference to Figures 6 and 7. In the description of piston seals G20 and H20, when parts similar to those of the piston seal 20 of the embodiment are used, the reference numerals and names of those parts will be used as they are.

[0039] 6, the piston seal G20 of the first comparative embodiment has a main body portion G40 and a seal portion G34. The main body portion G40 has a structure similar to that of the second annular portion 40 of the embodiment. The main body portion G40 has an intermediate portion G41, a reference portion G42, a clutch contact portion G43, an outer edge portion G44, a bent portion G45, and a bent portion G46. The seal portion G34 is made of an elastomer and is vulcanized and bonded to a portion of the main body portion G40 facing the groove bottom 12a. The seal portion G34 is formed from the clutch contact portion G43 to the outer edge portion G44 of the main body portion G40. The seal portion G34 has an outer lip portion G34b and an inner lip portion G34c. The thickness of the seal portion G34 between the bent portion G45 and the inner circumferential wall 12c of the housing portion 10 is greater than the thickness of the seal portion G34 between the inner edge portion of the main body portion 32 and the inner circumferential wall 12c in the embodiment. The piston seal G20 has the seal portion G34, which forms a sealed closed space G22 between the groove portion 12. The contact surface of the clutch contact portion G43 with the clutch member 14 is the same as the contact surface of the clutch contact portion 43 with the clutch member 14 in the embodiment. The main body portion G40 is formed by pressing and / or forging a single panel-shaped member. That is, the piston seal G20 of the first comparative embodiment is formed from a single panel-shaped member and the seal portion G34.

[0040] 7, the piston seal H20 of the second comparative embodiment has a main body portion H40 and a seal portion H34. By having the seal portion H34, the piston seal H20 forms a sealed closed space H22 between itself and the groove portion 12. The main body portion H40 has an intermediate portion H41, a clutch contact portion H43, and a bent portion H45, instead of the intermediate portion G41, the clutch contact portion G43, and the bent portion G45 of the first comparative embodiment. The intermediate portion H41 extends radially inward more than the intermediate portion G41 of the first comparative embodiment. The bent portion H45 is disposed radially inward more than the bent portion G45 of the first comparative embodiment. The clutch contact portion H43 is contracted radially inward more than the clutch contact portion G43 of the first comparative embodiment. The contact surface of the clutch contact portion H43 with the clutch member 14 is smaller than the contact surface of the clutch contact portion 43 with the clutch member 14 of the embodiment. The main body portion H40 is formed by pressing and / or forging a single panel-shaped member. That is, the piston seal H20 of the second comparative embodiment is formed from a single panel-shaped member and the seal portion H34.

[0041] The comparative piston seals G20 and H20 can reciprocate between the housing portion 10 and the clutch member 14 using the protruding surface 11c of the central portion 11 of the housing portion 10 as a reference by the power FH and the biasing force FS. However, in the case of the piston seal G20 of the first comparative embodiment, the thickness of the seal portion G34 between the bent portion G45 and the inner circumferential wall 12c of the housing portion 10 is greater than the thickness of the seal portion 34 between the inner edge of the main body portion 32 and the inner circumferential wall 12c in the embodiment. Therefore, the sealing performance, durability, and vulcanization adhesion to the main body portion G32 of the seal portion G34 of the piston seal G20 are insufficient to meet the functions required of a piston seal for an actuator. Furthermore, because the seal portion G34 of the piston seal G20 is formed across the clutch contact portion G43, it is susceptible to the effects of the engagement and disengagement operation of the clutch contact portion G43 and the clutch member 14. In the case of the piston seal H20 of the second comparative embodiment, the contact surface of the clutch contact portion H43 with the clutch member 14 is smaller than the contact surface of the clutch contact portion 43 with the clutch member 14 of the embodiment. Therefore, the contact property of the piston seal H20 with the clutch member 14 is not sufficient to fulfill the function required of a piston seal for an actuator. In addition, since the seal portion H34 of the piston seal H20 is formed across the clutch contact portion H43, it is easily affected by the contact and separation operation between the clutch contact portion H43 and the clutch member 14. In this way, when operating based on the protruding surface 11c provided on the central portion 11 of the housing portion 10, a piston seal formed from a single panel-like member cannot easily provide all of the functions required of a piston seal due to structural issues.

[0042] On the other hand, the piston seal 20 of the embodiment is formed from a first annular portion 30 and a second annular portion 40. Specifically, the piston seal 20 has the functions of forming the closed space 22 and contacting the reference surface, contact body, and biasing portion of the actuator, respectively, shared between the first annular portion 30 and the second annular portion 40. As a result, the thickness of the seal portion 34 between the inner edge portion of the main body portion 32 of the first annular portion 30 and the inner circumferential wall 12c can be made thinner than in the first comparative embodiment. Therefore, the piston seal 20 of the embodiment has excellent sealing properties, durability, and vulcanization adhesion to the main body portion 32. Furthermore, because the seal portion 34 of the first embodiment is separated from the clutch contact portion 43 in the axial direction, it is less susceptible to the influence of the engagement and disengagement operation of the clutch contact portion 43 and the clutch member 14. Furthermore, the contact surface of the clutch contact portion 43 of the second annular portion 40 with the clutch member 14 is larger than that of the second comparative embodiment, so the piston seal 20 of this embodiment has excellent contact with the clutch member 14. Both the first annular portion 30 and the second annular portion 40 can be easily formed by pressing and / or forging a single panel-shaped member. Therefore, according to the embodiment of the piston seal 20, a piston seal can be provided with a simple configuration that forms a sealed closed space 22 between the groove portion 12 and moves back and forth between the protruding surface 11c provided outside the groove portion 12 and the clutch member.

[0043] The first annular portion 30 of the embodiment has a facing portion 32a and a rib portion 32b. That is, the first annular portion 30 has an L-shaped cross section formed by press working and / or forging. The second annular portion 40 of the embodiment has an intermediate portion 41 and a bent portion 46 that contact the facing portion 32a and the rib portion 32b, respectively. That is, the second annular portion 40 has a U-shaped cross section that follows the L-shaped cross section of the first annular portion 30 and is formed by press working and / or forging. Therefore, according to the piston seal 20 of the embodiment, the first annular portion 30 and the second annular portion 40 can be brought into contact with each other with a simple configuration.

[0044] The second annular portion 40 having the bent portion 45 of the embodiment is a panel-shaped portion formed by pressing and / or forging. Therefore, according to the piston seal 20 of the embodiment, the second annular portion 40 having the bent portion 45 can be easily formed by pressing and / or forging a flat metal material.

[0045] The second annular portion 40 of the embodiment has an outer edge portion 44 that comes into contact with the retainer 16 of the biasing portion 15. Therefore, according to the piston seal 20 of the embodiment, the biasing force FS of the spring portion 17 can be efficiently transmitted to the piston seal 20.

[0046] The second annular portion 40 of the embodiment has an intermediate portion 41 that comes into contact with the protruding portion 16b of the retainer 16 of the biasing portion 15. This increases the contact area between the second annular portion 40 and the biasing portion 15 compared to when the retainer 16 does not come into contact with the intermediate portion 41. Therefore, according to the piston seal 20 of the embodiment, the biasing force FS of the spring portion 17 can be transmitted to the piston seal 20 more efficiently.

[0047] As described above, an embodiment of the present invention has been described as an example, but the present invention is not limited to the above embodiment, and various modifications, changes, and improvements are possible within the scope of the technical concept of the present invention.

[0048] In the above-described embodiment, the piston seal 20 contacts both the retaining portion 16a and the protruding portion 16b of the retainer 16 at the outer edge portion 44 and the intermediate portion 41. However, the piston seal 20 according to the present disclosure may contact only one of the retaining portion 16a or the protruding portion 16b, as shown in Figures 8 and 9, as long as the piston seal 20 can sufficiently transmit the biasing force of the biasing portion 15. Furthermore, the piston seal 20 according to the present disclosure may directly contact the spring portion 17 without the retainer 16, as shown in Figure 10, as long as the piston seal 20 can sufficiently transmit the biasing force of the biasing portion 15.

[0049] The piston seal 20 of the embodiment is applied to a clutch piston mechanism of a non-rotary actuator for a vehicle. However, the application of the piston seal according to the present disclosure is not limited to the clutch piston mechanism of a non-rotary actuator for a vehicle. The piston seal according to the present disclosure may also be applied to a rotary actuator. Furthermore, the piston seal according to the present disclosure may also be applied to general-purpose machinery such as vehicle accessories, general industrial machinery, and construction machinery. [Explanation of symbols]

[0050] 10 Housing 11 Central part 11c Protruding surface (example of reference surface) 12 Groove 12a groove bottom 12b Outer wall (example of outer groove wall) 14 Clutch member 15. Actuation section 16 Cage 16a Holding part 17a Protrusion 17 Spring section 20 Piston seal 22 Closed space 30 First annular portion 32 Main body 32a Opposite part 32b Rib section 34 Seal part 40 Second annular section 41 Intermediate portion (part of the first contact portion) (part of the fourth contact portion) 42 Reference portion (an example of a second contact portion) 43 Clutch contact portion (an example of a third contact portion) 44 Outer edge (part of the fourth contact) 45 Bent section (example of connection section) 46 Bending portion (part of first contact portion) FH power FS biasing force H Hydraulic oil

Claims

1. A piston seal that is reciprocable by a biasing portion between a reference surface provided on the outside of an annular groove portion that is provided around an axis and that opens toward a first direction along the axis, and a clutch member that is provided away from the reference surface on the first direction side, a first annular portion concentric with the groove portion and forming a sealed closed space between the groove portion and the first annular portion; a second annular portion disposed between the first annular portion and the clutch member and configured to move integrally with the first annular portion, a first contact portion that contacts the first annular portion; a second contact portion that is capable of coming into contact with and separating from the reference surface; a third contact portion that comes into contact with the clutch member when the second contact portion is spaced apart from the reference surface, the third contact portion being spaced apart from the clutch member when the second contact portion is in contact with the reference surface; a fourth contact portion that contacts the biasing portion at a position radially spaced apart from the second contact portion and the third contact portion; and a second annular portion having A piston seal having

2. The groove portion is a groove bottom facing the first direction; an outer groove wall standing from a radially outer edge of the groove bottom; and The first annular portion includes: an opposing portion opposing the groove bottom; a rib portion extending from an outer periphery of the opposing portion toward the first direction along the outer groove wall; and The piston seal according to claim 1 , wherein the first contact portion contacts the opposing portion and the rib portion on a side opposite to the groove portion.

3. the second annular portion has, in order from a radially inner side to a radially outer side, the second contact portion, the third contact portion, and the first contact portion, the second annular portion is panel-shaped, 3. The piston seal according to claim 1, wherein the second annular portion has a connecting portion that is bent to connect the first contact portion and the third contact portion.

4. the biasing portion includes a spring portion and a retainer that holds one end of the spring portion and receives the biasing force; 4. The piston seal according to claim 1, wherein the fourth contact portion is in surface contact with the cage.

5. the retainer extends toward the first contact portion, The piston seal according to claim 4 , wherein the fourth contact portion overlaps the first contact portion in the radial direction.

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