JP2000266079A - Wet frictional member and frictional disc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the drag torque by forming a wet fcitional member by an annular flat body, and providing the member with a plurality of grooves penetrating from an inner peripheral edge of a surface opposite to a surface fixed to a frictional plate to an outer peripheral edge, and having the even number of bent parts on the way. SOLUTION: A plurality of grooved parts 81 is formed in the circumferential direction on a surface of a first frictional member 46a, the intervals therebetween may be uneven, the hydraulic fluid flows in the radial direction in the connection of a clutch for cooling a frictional surface, and the pressure holding effect can be obtained in the disconnection. The grooved part 81 has too bent parts 85, 86, and formed by a first grooved part 82, a second grooved part 83 and a third grooved part 84, the outer peripheral side ends of the grooved parts 82, 83 are positioned at R2 side in comparison with the inner peripheral side ends, and the grooved part 84 is approximately straightly extended. Whereby the hydraulic fluid mainly flows from the grooved part 82 at the frictional member 46a side, and the hydraulic fluid collides with the bent part 85, by which the pressure is increased and the dynamic pressure is generated. The frictional connecting part of a piston is energized from a frictional surface of a front cover to an axial transmission side, as a result, the drag torque is scarcely generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet friction member and a friction disk using the same.

[0002]

2. Description of the Related Art Generally, a torque converter can smoothly perform acceleration and deceleration because power is transmitted by a fluid. However, slippage of the fluid causes energy loss, resulting in poor fuel economy.

Therefore, some conventional torque converters are provided with a lock-up device for mechanically connecting an input side front cover and an output side turbine.
The lockup device is disposed in a space between the front cover and the turbine. The lock-up device mainly includes a disk-shaped piston that can be pressed against the front cover, a driven plate attached to the back side of the turbine, and a torsion spring that elastically connects the piston and the driven plate in the rotational direction. It is configured. An annular friction member is bonded to the piston at a position facing the flat friction surface of the front cover.

In the conventional lock-up device, the operation of the piston is controlled by hydraulic oil flowing in the torque converter body. Specifically, when the lock-up connection is released, hydraulic oil is supplied between the piston and the front cover from an external hydraulic operating mechanism. This hydraulic oil flows radially outward in the space between the front cover and the piston, and further flows into the torque converter body on the outer peripheral side. At the time of lock-up connection, hydraulic oil in the space between the front cover and the piston is drained from the inner peripheral side, and as a result, the piston moves to the front cover side. As a result, the friction member provided on the piston is pressed against the friction surface of the front cover. Thus, the torque of the front cover is transmitted to the turbine via the lock-up device.

[0005] In a conventional lock-up device, a double disc clutch that uses a plurality of friction plates to secure a plurality of friction surfaces is used in order to secure a sufficient torque transmission capacity.

[0006]

In a conventional lock-up device for a torque converter using a double-plate clutch, for example, a clutch coupling portion has a driven plate and drive plates disposed on both sides of the driven plate. . Wet friction facings are affixed to both sides of the driven plate, forming a friction surface between each drive plate. In such a double-plate clutch coupling portion having a plurality of friction surfaces, there has conventionally been a problem of drag torque. The drag torque refers to a drag torque generated when the drive plate and the driven plate come into contact with each other when the clutch is released due to a decrease in pressure or the like.

An object of the present invention is to reduce drag torque in a wet clutch such as a lock-up device of a torque converter.

[0008]

According to a first aspect of the present invention, there is provided a wet friction member fixed to a friction plate of a wet clutch. The wet friction member comprises an annular and flat body. The main body has a first surface fixed to the friction plate, a second surface on the opposite side, and a plurality of grooves formed on the second surface and penetrating from the inner peripheral edge to the outer peripheral edge and having an even number of curved portions on the way.

[0009] When the clutch is released, the friction plate is rotating relative to the other members adjacent thereto. Therefore, the fluid flows through the plurality of grooves formed on the surface of the wet friction member, and the fluids collide with each other in the curved portion or the fluid collides with the curved portion to generate resistance, and the pressure increases in the curved portion. .
That is, a dynamic pressure is generated between the wet friction member and another member, and the friction plate tends to separate from the other member. for that reason,
Drag torque decreases.

Here, in the case where the wet friction member according to the present invention is used on both surfaces of the friction plate, since the plurality of grooves have an even number of curved portions, the curved portions on both sides in the axial direction where the fluid collides are formed. Are the same. As a result, the dynamic pressure generated on both sides of the friction plate in the axial direction becomes the same, and the friction plate can maintain a predetermined position in the axial direction.

According to a second aspect of the present invention, in the wet friction member according to the first aspect, each groove has two curved portions.

According to a third aspect of the present invention, in the wet friction member according to the second aspect, each groove includes a first groove extending from the outer peripheral edge to the inner peripheral side, a second groove extending from the inner peripheral edge to the outer peripheral side, A third groove that connects the groove and the second groove and forms a curved portion at a joint with each other;

When the wet friction member is fixed to both surfaces of the friction plate, fluid collision occurs in the curved portion formed by the first groove portion and the third groove portion in one wet friction member, and the wet friction member on the opposite side is used. In the friction member, a fluid collision occurs at a curved portion formed by the second groove portion and the third groove portion. As a result, the dynamic pressure generated on both sides of the friction plate becomes equal.

According to a fourth aspect of the present invention, in the wet friction member according to the third aspect, the outer peripheral end of the first groove and the inner peripheral end of the second groove are located at substantially the same circumferential position. The circumferential end and the outer circumferential end of the second groove are at different circumferential positions.

In this wet friction member, the outer peripheral end and the inner peripheral end of the first groove are located at different positions in the circumferential direction, and the inner peripheral end and the outer peripheral end of the second groove are arranged in the circumferential direction. , One of the grooves is open in the rotational direction of the friction plate. For this reason, the flow rate of the fluid flowing into the groove is increased, and the dwelling effect is enhanced.

According to a fifth aspect of the present invention, in the wet friction member according to the third aspect, the first groove portion and the second groove portion extend in a substantially radial direction at different positions in the circumferential direction, and the third groove portion extends in a substantially circumferential direction. ing.

In this wet friction member, since the third groove extends substantially in the circumferential direction, the groove can be provided over a wide range without bending each groove at an acute angle. Since the area of the groove can be increased on the surface of the friction member, the cooling effect is enhanced.

The friction disk according to the present invention is used for a wet clutch, and includes a friction plate and a wet friction member. The friction plate has an annular friction connection. The wet friction member is a pair of members respectively attached to both surfaces of the friction connection part. The wet friction member is one according to any one of claims 1 to 5.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 shows a torque converter 1 in which one embodiment of the present invention is adopted. In FIG. 1, a torque converter 1
Is mainly composed of a front cover 2, a fluid operating section 3 composed of three types of impellers (impeller 10, turbine 11, stator 12) arranged concentrically with the front cover 2, and a front cover 2 and a turbine 11. And a lock-up device 4 arranged in the space C between the axial directions. Front cover 2 and impeller shell 1 of impeller 10
Reference numeral 5 denotes a fluid chamber A whose outer peripheral portion is fixed by welding and which is filled with hydraulic oil. A portion of the impeller shell 15 further extending from the impeller blade 16 is arranged on the outer peripheral side of the turbine 11 and is integrated with the outer peripheral tubular portion 8 of the front cover 2.

The front cover 2 is a member to which torque is input from a crankshaft (not shown) of the engine. The front cover 2 mainly includes a disk-shaped main body 5. A boss 6 is fixed to the center of the main body 5.
A plurality of nuts 7 are fixed to the outer peripheral side of the main body 5 on the side of the engine. An outer peripheral cylindrical portion 8 extending toward the transmission is formed on an outer peripheral portion of the main body 5. Outer cylindrical part 8
Are formed with projections and depressions that alternately project in the radial direction over the entire circumference. A lug or a spline 9 is formed inside the outer peripheral cylindrical portion 8 due to the unevenness. Further, an annular and flat friction surface 70 is formed on the outer peripheral portion inside the main body 5 of the front cover 2. The friction surface 70 faces the transmission side in the axial direction.

The fluid operating section 3 is disposed in the fluid chamber A on the transmission side in the axial direction. Thus, the inside of the fluid chamber A is divided into a fluid working chamber B including the fluid working section 3 and a space C formed between the main body 5 of the front cover 2 and the turbine 11.

The impeller 10 includes an impeller shell 15
A plurality of impeller blades 16 fixed inside the impeller shell 15, an impeller core 17 fixed inside the impeller blade 16, and an impeller hub 18 fixed to the inner peripheral edge of the impeller shell 15. I have.

The turbine 11 is located inside the fluid chamber A in the impeller 1.
0. The turbine 11 includes a turbine shell 20, a plurality of turbine blades 21 fixed to the turbine shell 20, a turbine core 22 fixed inside the turbine blade 21, and a turbine shell 2.
And a turbine hub 23 fixed to the inner peripheral edge of the turbine hub 23. The turbine hub 23 is a cylindrical member, and has a flange 26 on the outer peripheral side. The flange 26 is fixed to the inner peripheral portion of the turbine shell 20 by a plurality of rivets 24. Further, a spline 25 is formed on the inner peripheral edge of the turbine hub 23. The spline 25 is engaged with a shaft (not shown) extending from the transmission side. Thus, the torque from the turbine hub 23 is output to a shaft (not shown).

The stator 12 is disposed between the inner periphery of the impeller 10 and the inner periphery of the turbine 11. Stator 12 is a mechanism for rectifying the flow of hydraulic oil returning from turbine 11 to impeller 10. The stator 12 includes a stator carrier 27, a plurality of stator blades 28 fixed to an outer peripheral surface thereof, and a stator core 29 fixed inside the stator blade 28. Further, the stator carrier 27 is supported by a fixed shaft (not shown) via a one-way clutch 30.

A first thrust bearing 32 is arranged between the main body 5 of the front cover 2 and the turbine hub 23 in the axial direction. A plurality of grooves extending in the radial direction are formed on the end face on the engine side in the axial direction of the turbine hub 23, and these grooves allow hydraulic oil to flow on both radial sides of the first thrust bearing 32. A second thrust bearing 33 is disposed between the turbine hub 23 and the one-way clutch 30. A plurality of grooves extending in the radial direction are formed on a member constituting the one-way clutch 30 on the engine side in the axial direction. These grooves allow the hydraulic oil to flow between both sides in the radial direction of the second thrust bearing 33.

The stator carrier 37 and the impeller hub 1
A third thrust bearing 34 is arranged between the third thrust bearing 34 and the axial direction. A plurality of grooves extending in the radial direction are formed on the transmission side of the stator carrier 27 in the axial direction. These grooves allow hydraulic oil to flow between both sides in the radial direction of the third thrust bearing.

In this embodiment, the impeller hub 1
The first oil passage of the hydraulic operation mechanism is connected between the stator 8 and the stator 12 in the axial direction, and the second oil passage of the hydraulic operation mechanism is connected between the stator 12 and the turbine hub 23 in the axial direction. A third oil passage of the hydraulic operation mechanism is connected to the inner peripheral portion of the front cover 2. The first oil passage and the second oil passage are usually connected to a common hydraulic circuit, and both supply the hydraulic oil to the fluid operating unit 3 or discharge the hydraulic oil from the fluid operating unit. The third oil passage is formed inside the shaft, and is capable of supplying hydraulic oil between the front cover 2 and the turbine hub 23, that is, the inner peripheral portion of the space C, or discharging the hydraulic oil from the space C. .

Next, the space C will be described. The space C is an annular space formed between the main body 5 of the front cover 2 and the turbine 11 in the axial direction. The space C is formed by the main body 5 of the front cover 2 on the engine side in the axial direction and by the turbine shell 20 of the turbine 11 on the transmission side in the axial direction. Further, the outer peripheral side of the space C is mainly formed by the inner peripheral surface of the outer cylindrical portion 8, and the inner peripheral side is formed by the outer peripheral surface of the turbine hub 23. As described above, the space C is connected to an external hydraulic operating mechanism on the inner circumferential side, that is, between the inner circumferential portion of the front cover 2 and the turbine hub 23. Further, the space C communicates with the fluid working chamber B through a gap between the impeller 10 outlet and the turbine 11 inlet at the outer peripheral portion.

The lock-up device 4 is a device that is disposed in the space C and mechanically connects and disconnects the front cover 2 and the turbine 11 by a change in hydraulic pressure in the space C. The lock-up device 4 mainly includes a piston mechanism 41 and a piston 42.

The piston mechanism 41 has a piston function which operates by a change in oil pressure in the space C, and a damper function for absorbing and attenuating torsional vibration in the rotational direction.

The piston mechanism 41 includes a first piston 43 and a damper mechanism 44. First piston 4
Numeral 3 is a disk-shaped member arranged in the space C close to the main body 5 side of the front cover 2. First piston 4
Reference numeral 3 mainly includes a disk-shaped plate 45, and divides the space C into a first space D on the front cover 2 side and a second space E on the turbine 11 side. The outer peripheral portion of the plate 45 has a first frictional coupling portion 49 disposed axially preparative Ransumi <br/> cushion side of the friction surface 70 of the front cover 2. The first friction connecting portion 49 is an annular and flat plate-like portion, and annular friction members 46 are attached to both sides in the axial direction.
The friction member 46 facing the friction surface 70 is a first member.
The friction member 46a is referred to as a second friction member 46b. The inner peripheral cylindrical portion 7 is provided on the inner peripheral edge of the plate 45.
1 is formed. The inner peripheral cylindrical portion 71 extends from the inner peripheral edge of the plate 45 toward the transmission in the axial direction.
The inner peripheral surface of the inner peripheral cylindrical portion 71 is the outer peripheral surface 6 of the turbine hub 23.
5 support the movably in the axial and rotational directions. On the outer peripheral surface of the turbine hub 23, an annular contact portion 4 located on the axial transmission side of the inner cylindrical portion 71.
8 are formed. This restricts the movement of the plate 45 toward the transmission in the axial direction. Note that an annular groove is formed in the outer peripheral surface 65, and a seal ring 57 is disposed in the groove. The seal ring 57 is in contact with the inner peripheral surface of the inner peripheral cylindrical portion 71. The seal ring 57 seals between the first space D and the second space E.

As described above, the inner periphery of the first space D communicates with the third oil passage, and the second space E is formed by the inner periphery of the first piston 43 and the outer peripheral surface 65 of the turbine hub 23.
The outer peripheral portion is cut off from the second space E in a state where the first frictional connection portion 49 is in contact with the friction surface 70 and communicates with the second space E in a state where the first frictional connection portion 49 is away from the second space E.

The damper mechanism 44 is a mechanism for transmitting torque from the first piston 43 to the turbine 11 and for absorbing and attenuating torsional vibration. The damper mechanism 44 is disposed between the inner periphery of the first piston 43 and the inner periphery of the turbine shell 20 in the second space E. The damper mechanism 44 mainly includes a drive member 50, a driven member 51, and a torsion spring 52. The drive member 50 is firmly fixed to the first piston 43. The driven member 51 can output torque to the turbine 11. The torsion spring 52 elastically connects the drive member 50 and the driven member 51 in the rotational direction. More specifically,
The drive member 50 includes a first drive plate 54 and a second drive plate 55. Both drive plates 54 and 55 are plates formed in an annular shape, and are arranged side by side in the axial direction. The first drive plate 54 is arranged close to the plate 45 of the first piston 43 on the axial transmission side. The second drive plate 55 is arranged on the transmission side of the first drive plate 54 in the axial direction. The outer peripheral portions of both drive plates 54 and 55 are fixed to the first piston 43 by a plurality of rivets 56. The inner peripheral portions of the first drive plate 54 and the second drive plate 55 are arranged apart from each other in the axial direction. Further, a plurality of square windows 35 and 36 with which the torsion spring 52 is engaged are formed in both the drive plates 54 and 55. The second drive plate 55 is provided with a rivet 5 as shown in FIG.
6 outer peripheral portion 55a fixed to the first piston 43
And a tubular portion 55b extending from the outer peripheral portion 55a toward the transmission in the axial direction, and an annular portion 55c extending radially inward from the tubular portion 55b. The aforementioned square windows 35 and 36 are formed in the annular portion 55c. Driven member 5
Reference numeral 1 denotes an annular plate whose outer peripheral portion is disposed between the drive plates 54 and 55 in the axial direction. Window holes 58 are formed in the driven member 51 at positions corresponding to the square windows of the drive plates 54 and 55. Window hole 58
A torsion spring 52 is disposed inside. The torsion spring 52 is a coil spring extending in the rotation direction. The rotation direction of the torsion spring 52 is supported by the window hole 58 and the square windows 35 and 36 described above. Further, the axial movement of the torsion spring 52 is restricted by the square windows 35, 36 of the drive plates 54, 55. A cylindrical portion 38 extending toward the transmission in the axial direction is formed on an inner peripheral portion of the driven member 51. A plurality of claws 59 are formed on the cylindrical portion 38 and extend further from the front end toward the transmission in the axial direction.

The damper mechanism 44 further has a claw member 53. The claw member 53 is a member that is firmly fixed to the turbine 11 and rotates integrally with the turbine 11. The claw member 53 is a member that allows relative rotation with respect to the driven member 51 and movement in the axial direction. The claw member 53 has an annular portion 60 fixed to the turbine hub 23 together with the turbine shell 20 by the rivets 24. A claw portion 61 extending radially inward from the inner peripheral edge of the annular portion 60 is formed. The claw portion 61 is a driven member 51
Are engaged with each other. In this state, the driven member 51 cannot rotate relative to the turbine 11 and can move in the axial direction. In addition, at the engagement portion between the claw portion 61 and the claw 59, a gap communicating in the axial direction in the radial direction is secured.

The outer peripheral surface of the cylindrical portion 38 of the driven member 51 contacts the inner peripheral surface of the second driven plate 55 and is supported in the radial direction. Thus, the driven member 51 is centered with respect to the turbine hub 23 via the second drive plate 55 and the first piston 43.

As described above, since it is not necessary to directly position the driven member 51 with respect to the turbine hub 23 in the radial direction, it is necessary to form a spline on the turbine hub 23 in the engagement between the piston mechanism 41 and the turbine 11. Absent. As a result, the overall processing cost is reduced.

The piston 42 is moved in the first space
The piston 43 is disposed on the transmission side in the axial direction of the outer peripheral portion and on the outer peripheral side of the damper mechanism 44. The piston 42 is an annular plate.
9 has a second friction coupling portion 68 adjacent to the axial transmission side. As shown in FIG. 2, the second friction coupling portion 68 has an annular and flat shape, and has a pressing surface 69 on the engine side in the axial direction. The pressing surface 69 faces the second friction member 46b in the axial direction. Piston 42
An outer peripheral cylindrical portion 62 extending toward the transmission in the axial direction is formed on the outer peripheral edge of the transmission. The outer cylindrical portion 62 is disposed close to the inner peripheral surface of the outer cylindrical portion 8 of the front cover 2. The outer cylindrical portion 62 is formed with teeth 64 projecting alternately on both sides in the radial direction. Teeth 64 are front cover 2
Lugs or splines 9 formed on the outer peripheral cylindrical portion 8 of the diaper. By this engagement, the piston 42 is not rotatable relative to the front cover 2 and is movable in the axial direction. An annular groove is formed in a portion of the lug or spline 9 on the transmission side in the axial direction.
A wire ring 67 is arranged in the groove. The axial transmission end face of the outer peripheral cylindrical portion 62 of the piston 42 abuts on the wire ring 67, thereby restricting the movement of the piston 42 toward the axial transmission. A gap is formed in the engagement portion between the tooth 64 and the lug or spline 9 so that the hydraulic oil can move in the axial direction.

An inner peripheral cylindrical portion 63 extending toward the transmission in the axial direction is formed on the inner peripheral edge of the piston 42. The inner peripheral edge of the inner peripheral cylindrical portion 63 is the second drive plate 5
5 is supported by the outer peripheral surface 73 of the cylindrical portion 55b, is positioned in the radial direction, and is movable in the rotation direction and the axial direction. Further, an annular groove is formed in the outer peripheral surface 73, and a seal ring 66 is disposed therein. The seal ring 66 is in contact with the inner peripheral surface of the inner cylindrical portion 63. This seal ring 66 allows the piston 4
The spaces on both sides in the axial direction are sealed from each other at the inner peripheral edge of 2. Thus, the third space F is formed mainly between the outer peripheral portion of the first piston 43 and the piston 42 in the axial direction. The third space F is isolated from other parts of the second space E by the above-described seal ring 66.
Further, the third space F is closed on the outer peripheral side when the first frictional connection portion 49 and the second frictional connection portion 68 are in contact with each other, and is open when the two are away from each other. Third
Since the space F is formed between the piston 42 and the plate 45, the number of parts is reduced and the structure is simplified. Further, the first frictional connection portion 4
A plurality of holes 47 penetrating in the axial direction are formed in a radially inner portion of the nozzle 9. This hole 47 allows the first space D
And the third space F communicate with each other.

With the above description summarized, the clutch connecting portion 40 of the lockup device 4 will be described. The clutch connecting portion 40 includes a friction surface 70 of the front cover 2, a first friction connecting portion 49 of the first piston 43, and a piston 42.
And the pressing surface 69 of the second friction coupling portion 68. Thus, the clutch connecting portion 40 has two friction surfaces. Note that the piston 42 and the second drive plate 55 rotate relative to each other in a state where the clutch connecting portion 40 is disconnected. However, in the state where the clutch connecting portion 40 is connected, the two rotate integrally, and the inner peripheral cylindrical portion 63 and the cylindrical portion 55b
Does not slide in the direction of rotation.

Here, since the first friction connecting portion 49 and the second friction connecting portion 68 are pistons which move in the axial direction by themselves, the first piston is provided between the friction surface 70 and the friction member 46. 43, the friction member 4
The pressing force from the piston 42 acts between 6 and the pressing surface 69.

In the clutch connecting portion 40, the piston 4
2 is the inner diameter of the first piston 43 (ID2).
1) When the inner diameter of the piston 42 is greater than the first pressure,
It is smaller than when it is equal to the inner diameter of the piston 43. Therefore, a smaller pressing force can be generated as compared with the case where the friction surface is simply doubled, and wear and breakage of the friction member 46 and the like can be suppressed. Further, by changing the size of the piston 42, the pressing force acting on the clutch connecting portion 40 can be easily changed. The inner diameter of the piston 42 can be said to be greater than the inner diameter of the piston mechanism 4 1. Such a structure exhibits the above-described excellent effects when the piston mechanism 41 is not provided with the damper mechanism 44.

Since the piston 42 is arranged on the outer peripheral side of the damper mechanism 44 as an input member which rotates integrally with the front cover 2, more specifically, the inner diameter of the piston 42 is larger than the outer diameter of the damper mechanism 44 and Are arranged on the outer periphery of the damper mechanism 44, so that the space on one side in the axial direction of the damper mechanism 44 is not restricted.
Therefore, the axial dimension of the torsion spring 52 in the damper mechanism 44 can be increased. Thereby, the design becomes easy, and the high functionality of the torsion spring 52 such as lower rigidity can be realized.

Further, the piston 42 as a piston member which moves in the axial direction by itself is supported in a radial direction by a part of the damper mechanism 44, in particular, by the second drive plate 55 constituting a drive member.
This eliminates the need to provide a special member or configuration for supporting the lockup device, thereby simplifying the structure of the lockup device 4 as a whole.

Next, the operation will be described. In the clutch disengaged state, hydraulic oil is supplied from the third oil passage to the inner peripheral side of the first space D. The hydraulic oil in the first space D flows radially outward, flows between the friction surface 70 and the first friction member 46a, and further passes through the gap between the lug or spline 9 and the teeth 64, and the second space E. Flows to the outer periphery side of. The hydraulic oil in the second space E includes the impeller shell 15 and the turbine shell 20.
Flows into the fluid working chamber B from the gap between the impeller 10 outlet and the turbine 11 inlet. Also, the first
The hydraulic oil moving in the space D flows into the third space F through a hole 47 formed in the first piston 43. The hydraulic oil in the third space F flows radially outward between the pressing surface 69 and the second friction member 46b. The hydraulic oil also flows to the outer peripheral side of the second space E through the gap between the lug or spline 9 and the teeth 64.

Here, the first piston 43 and the piston 4
2 function as pistons that move in the axial direction due to changes in oil pressure in the space C, so that the axial movement of both members is stable. Therefore, the clutch connecting portion 40
, Each member is difficult to contact with each other. Specifically, the movement of the piston 42 toward the transmission in the axial direction is restricted by the wire ring 67, and the movement of the first piston 43 in the axial direction is restricted by the turbine hub 23. As a result, as shown in FIG.
A predetermined clearance is secured between the friction member 46a and between the second friction member 46b and the pressing surface 69.

Next, the clutch connecting operation will be described. The hydraulic oil in the first space D is drained from the third oil passage.
Thus, the hydraulic oil in the first space D flows toward the inner peripheral side, and the hydraulic oil in the third space F flows into the first space D through the hole 47. As a result, the first piston 43 moves to the engine side in the axial direction, and the first frictional connecting portion 49 is moved to the front cover 2.
Abuts on the friction surface 70. Further, the piston 42 also moves toward the engine side in the axial direction, and the pressing surface 69 moves to the second friction member 46.
b. Thus, the first space D is formed by the hole 47.
And the third space F communicate with each other, whereby the operation of the piston 42 becomes smooth.

Next, the clutch release operation will be described.
When the hydraulic oil is supplied from the third oil passage into the first space D, the hydraulic oil moves to the outer peripheral side, and further passes through the hole 47 to the third oil passage.
It flows into the space F. As a result, the first piston 43 and the piston 42 move toward the transmission in the axial direction. Thus, the operation of the piston 42 is smoothened by the hole 47. [Holding Effect by Friction Facing Groove in Clutch Connection] The first friction connection 49 of the first piston 43 has an annular and flat shape, and friction members 46 are affixed on both axial sides. The first piston 43 functions as a friction disk for a wet clutch including a friction plate and friction members stuck on both sides thereof.

The shape of the first friction member 46a will be described with reference to FIG. The main body of the first friction member 46a has an annular and flat plate shape, and is fixed to the side surface of the first friction connection portion 49 in the axial direction of the engine. The first surface of the first friction member 46a is affixed to the first friction coupling portion 49 with an adhesive or the like,
The second surface faces the friction surface 70. This second surface is a friction engagement surface.

On the second surface of the first friction member 46a, a plurality of grooves 75 are formed in a circumferential direction. Groove 75
When the clutch is engaged, the hydraulic oil flows in the radial direction to cool the friction surface, and when the clutch is disengaged, a pressure retention effect described later is obtained. In FIG. 4, the grooves 75 are arranged at equal intervals in the circumferential direction, but may be at irregular intervals. As shown in FIG. 5, each portion 74 divided in the circumferential direction by the groove 75 serves as the above-described friction engagement surface.

The shape of each groove 75 will be described. Each groove portion 75 is a groove penetrating from the inner peripheral edge to the outer peripheral edge of the first friction member 46a, and has a curved portion 78 in the middle. The term “curved portion” as used herein refers to a portion where the direction of the groove changes midway, and refers to a portion where the fluid flowing up to that collides with the wall surface. Each groove 75 includes a first groove 76 extending from the outer peripheral edge to the inner peripheral side, and a second groove 77 extending from the inner peripheral edge to the outer peripheral side. The outer peripheral end of the first groove portion 76 is located on the R2 side relative to the inner peripheral end. The second groove 77 has an inner peripheral end located closer to the R2 side than an outer peripheral end. The outer peripheral end of the first groove 76 and the inner peripheral end of the second groove 77 are located at substantially the same position in the circumferential direction. That is, the groove 75 has a V-shape that opens toward the arrow R2.

The depth of the groove portion 75 does not reach the first frictional connection portion 49, and the first frictional connection portion 49 is not exposed on the friction surface 70 side. However, a groove in which the first friction coupling portion 49 is exposed may be formed by, for example, arranging a plurality of friction facing pieces in a ring shape.

With the clutch connecting portion 40 disconnected, the piston 42 rotates integrally with the front cover 2, and the first piston 43 rotates integrally with the turbine 11. Here, since there is a speed difference between the impeller 10 and the turbine 11, the first piston 43 rotates relative to the front cover 2 and the piston 42. That is, in each of the gap X between the friction surface 70 and the first friction member 46a and the gap Y between the second friction member 46b and the pressing surface 69,
The members on both sides are rotating relative to each other. Note that an arrow R1 in FIG. 4 is a rotation direction of the first piston 43, and an arrow R2.
Is the rotation direction of the first piston 43 with respect to the front cover 2 at the time of clutch release.

In the first friction member 46a, the first groove 7
Hydraulic oil flows between 6 and the inside of the second groove 77, and the hydraulic oil collides at the curved portion 78. The pressure increases at the curved portion 78, and as a result, the first
A dynamic pressure is generated on the surface of the friction member 46a. Therefore, the first friction connecting portion 43 of the first piston 43 is urged from the friction surface 70 of the front cover 2 toward the transmission in the axial direction, and as a result, drag torque is hardly generated.

When the relative rotation direction of the first piston is on the arrow R1 side, each groove 75 is formed by the V open to the R1 side.
It needs to be in the shape of a letter.

The angle θ formed between the first groove 76 and the second groove 77 is 120 ° in FIG. This angle θ is desirably 90 ° to 140 °. If the angle is 90 ° or less, the durability of the first friction member 46a decreases. On the other hand, when the angle exceeds 140 °, the pressure holding effect due to the collision of the hydraulic oil decreases.

The plurality of grooves 7 are formed on the surface of the second friction member 46b.
5 may be formed. It is preferable that those grooves are also V-shaped open in the rotation direction. In this case, a pressure-holding effect is obtained in the gap Y. Second Embodiment A plurality of grooves 81 are formed on the surface of a first friction member 46a shown in FIG. In FIG. 6, the grooves 81 are arranged at equal intervals in the circumferential direction, but may be at irregular intervals. The groove 81 cools the friction surface by flowing the hydraulic oil in the radial direction when the clutch is connected, and obtains a pressure holding effect described later when the clutch is released.

The shape of each groove 81 will be described. Each groove portion 81 has an even number, specifically, two curved portions 85 and 86. Each groove portion 81 includes a first groove portion 82 extending from the outer peripheral edge to the inner peripheral side, and a second groove portion 83 extending from the inner peripheral edge to the outer peripheral side.
And a third groove 84 connecting the first groove 82 and the second groove 83. The outer peripheral end of the first groove portion 82 is located on the R2 side relative to the inner peripheral end. Second groove 83
The outer peripheral end is located on the R2 side as compared with the inner peripheral end.
The third groove 84 extends substantially linearly. As a result, the first groove 82 and the third groove 84 form a curved portion 85 opened to the R2 side, and the second groove 83 and the third groove 84 A curved portion 86 opened to the R1 side is formed. The first
The outer peripheral end of the groove 82 and the inner peripheral end of the first groove 82 are arranged at substantially the same position in the circumferential direction. The angle θ1 formed by the first groove 82 and the third groove 84 is 120 °,
The angle θ2 formed by the second groove 83 and the third groove 84 is 120 °.

In FIG. 7, the first friction member 46a and the second friction member 46a
The arrangement of the grooves 81 when the same friction facing is used for the friction member 46b is shown. On the first friction member 46a side and the second friction member 46b side, the inclination of the first groove 82, the second groove 83, and the third groove 84 in each groove 81 is opposite.

The depth of the groove portion 81 does not reach the first frictional connection portion 49, and the first frictional connection portion 49 is not exposed on the friction surface 70 side. However, the groove 81 in which the first friction coupling portion 49 is exposed may be formed by, for example, arranging a plurality of friction facing pieces in an annular shape.

When the clutch connecting portion 40 is disconnected, the piston 42 rotates integrally with the front cover 2, and the first piston 43 rotates integrally with the turbine 11. Here, since there is a speed difference between the impeller 10 and the turbine 11, the first piston 43 rotates relative to the front cover 2 and the piston 42. That is, the members on both sides are relatively rotated by the gap X between the friction surface 70 and the first friction member 46a and the gap Y between the second friction member 46b and the pressing surface 69. The arrow R1 in FIG.
Is the rotation direction of the first piston 43, and the arrow R2 is the rotation direction of the first piston 43 with respect to the front cover 2 at the time of clutch release.

On the first friction member 46a side, hydraulic oil mainly flows from the first groove portion 82, and the hydraulic oil collides with the curved portion 85. The pressure increases at the curved portion 85, and as a result, a dynamic pressure is generated on the surface of the first friction member 46a. Therefore, the first friction connecting portion 43 of the first piston 43 is urged from the friction surface 70 of the front cover 2 toward the transmission in the axial direction, and as a result, drag torque is hardly generated.

On the second friction member 46b side, the working oil mainly flows from the second groove 83, and the working oil collides with the curved portion 86. The pressure increases at the curved portion 86, and as a result, a dynamic pressure is generated on the surface of the second friction member 46b. Therefore, the first frictional connection portion 43 of the first piston 43 is urged from the pressing surface 69 of the piston 42 toward the engine in the axial direction, and as a result, drag torque hardly occurs.

As described above, since the hydraulic oil collides with one curved portion on each side of the first frictional connection portion 49 in the axial direction, the dynamic pressure generated on both axial sides of the first frictional connection portion 49 is substantially the same. become. As a result, the first piston 43 can maintain a substantially neutral position in the axial direction.

In this way, good results can be obtained even if one type of friction facing is applied to both sides. As a result,
It is not necessary to prepare two patterns of friction facing, and the cost is reduced. Third Embodiment On the surface of a first friction member 46a shown in FIG. 8, a plurality of grooves 88 are formed in a circumferential direction. In FIG. 8, the grooves 88 are arranged at equal intervals in the circumferential direction, but may be at irregular intervals. The groove portion 88 cools the friction surface by flowing the hydraulic oil in the radial direction when the clutch is connected, and obtains a pressure holding effect described later when the clutch is released.

The shape of each groove 88 will be described. Each groove portion 88 has an even number, specifically, two curved portions 93 and 94. Each groove 88 includes a first groove 90 extending from the outer peripheral edge to the inner peripheral side, and a second groove 9 extending from the inner peripheral edge to the outer peripheral side.
1, a third groove 92 connecting the first groove and the second groove 91
It is composed of Each of the first groove portion 90 and the second groove portion 91 is a groove extending substantially in the radial direction. Second groove 91
Are formed on the R2 side with respect to the first groove portion 90. The third groove 92 extends substantially in the circumferential direction. A curved portion 93 is formed by the R1 end of the third groove 92 and the inner peripheral end of the first groove 90, and a curved portion 94 is formed by the R2 end of the third groove 92 and the outer peripheral end of the second groove 91. Is formed. An angle θ3 formed by the first groove 90 and the third groove 92 is substantially 90 °, and an angle θ4 formed by the second groove 91 and the third groove 92 is substantially 90 °. In this embodiment, the first groove portion 90 and the second groove portion 91 are further separated in the circumferential direction, and the third groove portion 92 is made longer in the circumferential direction, so that the angle of each curved portion is not acute. The area occupied by the surface 88 on the friction surface can be increased. Thereby, the clutch cooling effect is improved. Note that the sharper the angle of each curved portion, the lower the durability of the friction member.

FIG. 9 shows the position of each groove 88 when this friction facing is fixed to the first friction member 46a and the second friction member 46b. On the second friction member 46b side, the first groove 90 is located on the R2 side with respect to the second groove 91.

The effect of reducing the drag torque due to the collision of the hydraulic oil is the same as in the above embodiment.

The depth of the groove portion 81 does not reach the first frictional connection portion 49, and the first frictional connection portion 49 is not exposed on the friction surface 70 side. However, the groove 81 in which the first friction coupling portion 49 is exposed may be formed by, for example, arranging a plurality of friction facing pieces in an annular shape.

In a state where the clutch connecting portion 40 is disconnected, the piston 42 rotates integrally with the front cover 2, and the first piston 43 rotates integrally with the turbine 11. Here, since there is a speed difference between the impeller 10 and the turbine 11, the first piston 43 rotates relative to the front cover 2 and the piston 42. That is, the members on both sides are relatively rotated by the gap X between the friction surface 70 and the first friction member 46a and the gap Y between the second friction member 46b and the pressing surface 69. The arrow R1 in FIG.
Is the rotation direction of the first piston 43, and the arrow R2 is the rotation direction of the first piston 43 with respect to the front cover 2 at the time of clutch release.

The hydraulic oil flows through the third groove 92 to the R2 side in the first friction member 46a and collides at the curved portion 94. The pressure increases at the curved portion 94, and as a result, the first friction member 46
A dynamic pressure is generated on the surface of a. Therefore, the first friction connecting portion 43 of the first piston 43 is urged from the friction surface 70 of the front cover 2 toward the transmission in the axial direction,
As a result, drag torque hardly occurs.

On the second friction member 46b side, the hydraulic oil flows through the third groove portion 92 to the R2 side and collides with the hydraulic oil at the curved portion 93. The pressure increases at the curved portion 93, and as a result, a dynamic pressure is generated on the surface of the second friction member 46b. Therefore, the first friction connecting portion 43 of the first piston 43
Is pressed toward the engine side in the axial direction from the pressing surface 69, and as a result, drag torque hardly occurs.

As described above, since the hydraulic oil collides at one curved portion on each side of the first frictional connection portion 49 in the axial direction, the dynamic pressure generated on both axial sides of the first frictional connection portion 49 is substantially the same. become. As a result, the first piston 43 can maintain a substantially neutral position in the axial direction.

In this way, good results can be obtained even if one type of friction facing is applied to both sides. As a result,
It is not necessary to prepare two patterns of friction facing, and the cost is reduced. [Other Embodiments] The friction member according to the present invention or the friction disk for a wet clutch using the same is not limited to the structure of the first piston 43 in the present embodiment. For example, it can be applied to a clutch plate having no piston function. The wet clutch to which the present invention is applied is not limited to the lock-up device, but may be a power cut-off clutch. Further, the wet clutch to which the present invention is applied is not limited to a torque converter, and may be, for example, a transmission multi-plate clutch.

In the second and third embodiments, if the number of curved portions in each groove is an even number, substantially the same dynamic pressure can be obtained on both axial sides of the friction disk. If the number of songs is four,
There are two curved portions where the hydraulic oil mainly collides on one side, and two curved portions where the hydraulic oil mainly collide on the other side. Also in this case, there is no need to prepare two patterns of friction facing,
Cost is reduced.

[0075]

In the friction disk according to the present invention, since the plurality of grooves have an even number of curved portions, the number of curved portions where fluid collision occurs on both sides in the axial direction is the same. As a result,
The dynamic pressure generated on both sides in the axial direction of the friction plate becomes the same, and the friction plate can maintain a predetermined position in the axial direction.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a torque converter to which an embodiment of the present invention is applied.

FIG. 2 is a partially enlarged view of FIG. 1, showing a clutch connecting portion of the lock-up device.

FIG. 3 is a partially enlarged view of FIG. 1, showing support of a piston by a damper mechanism.

FIG. 4 is a partial plan view for explaining a groove shape of friction facing.

FIG. 5 is a view taken in the direction of the arrow V in FIG. 4;

FIG. 6 is a partial plan view for explaining a groove shape of the friction facing.

FIG. 7 is a partial plan view for explaining a groove shape of the friction facing.

FIG. 8 is a partial plan view for explaining a groove shape of friction facing.

FIG. 9 is a partial plan view for explaining the groove shape of the friction facing.

[Explanation of symbols]

 46a First friction member 81 Groove 82 First groove portion 83 Second groove portion 84 Third groove portion 85 Curved portion 86 Curved portion 88 Groove 90 First groove portion 91 Second groove portion 92 Third groove portion 93 Curved portion 94 Curved portion

Claims (6)

[Claims] 1. A wet friction member fixed to a friction plate of a wet clutch, comprising a ring-shaped and flat main body, wherein the main body has a first surface fixed to the friction plate and a second surface opposite to the first surface. A wet friction member comprising: a surface; and a plurality of grooves formed on the second surface and penetrating from an inner peripheral edge to an outer peripheral edge and having an even number of curved portions on the way. 2. The wet friction member according to claim 1, wherein each of said grooves has two of said curved portions. 3. Each of the grooves connects a first groove extending from the outer peripheral edge to the inner peripheral side, a second groove extending from the inner peripheral edge to the outer peripheral side, and the first groove and the second groove. 3. The wet friction member according to claim 2, further comprising a third groove that forms the curved portion at a joint portion with each other. 4. 4. An outer peripheral end of the first groove and an inner peripheral end of the second groove are located at substantially the same circumferential position, and an inner peripheral end of the first groove and an outer peripheral side of the second groove. 4. The wet friction member of claim 3, wherein the ends are at different circumferential positions. 5. The wet friction of claim 3, wherein said first groove and said second groove extend substantially radially at different circumferential positions, and said third groove extends substantially circumferentially. Element. 6. A friction disc used in a wet clutch, comprising: a friction plate having an annular friction connection portion; and a pair of friction plates respectively attached to both surfaces of the friction connection portion. And a wet friction member according to any one of claims 1 to 4.