JP2000081107A - Piston for lockup of torque converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve friction performance of a part friction-coupled to the other member, in a piston at which an axially extending cylindrical part is formed at an outer peripheral edge. SOLUTION: A piston 10 is arranged between a front cover of a torque converter and a turbine axially thereof, axially movable due to a change in a hydraulic pressure, and coupled to a driven plate 7 through a torsion spring 4. The piston 10 comprises a disc-form member 2; a retaining plate 3; and an annular member 30. The disc-form member 2 is provided with a disc-form part 11, and an annular part 12 formed on the outer peripheral side of the disc-form part 11 and friction-engaged with other member. The retaining plate 3 is fixed on the surface on the turbine side of the annular part 12 and supports the torsion spring 4. The retaining plate 3 has a cylinder part 18 to support the outside in a radial direction of the torsion spring 4. The annular member 30 is engaged with the outer peripheral surface of the cylindrical part 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock-up piston for a torque converter, and more particularly to a piston using a disk-shaped member having a cylindrical portion extending in the axial direction on the outer periphery.

[0002]

2. Description of the Related Art A torque converter is a device having three types of impellers (impeller, turbine, and stator) inside, and transmitting torque by internal working oil. The impeller is fixed to a front cover connected to the input side rotating body, and torque is transmitted to the output side by hydraulic oil flowing from the impeller to the turbine. The lockup device is arranged between the turbine and the front cover, and is a device for directly transmitting torque from the front cover to the output side member by mechanically connecting the front cover and the turbine.

Normally, this lock-up device includes a piston that can be pressed against the front cover, a retaining plate fixed to the piston, a torsion spring supported by the retaining plate, and a resilient spring that is elastically applied to the piston by the torsion spring. And a driven plate, which is connected to each other. The driven plate is fixed to a turbine connected to the output side rotating body.

[0004] The piston can be moved in the axial direction by a difference in oil pressure on both sides in the axial direction. Then, when the friction facing annularly stretched on the outer peripheral portion of the piston comes into contact with the friction surface of the front cover, the torque of the front cover is transmitted to the lock-up device.

[0005]

It is desirable that the friction surface of the front cover is flat, but in practice, the friction surface may undulate due to welding or the like. In such a case, even if the friction facing of the piston comes into contact with the friction surface of the front cover, the annular portion of the piston cannot follow the change of the friction surface on the front cover side because the rigidity is high,
Therefore, the friction performance decreases. This causes a problem that vibration cannot be sufficiently absorbed and attenuated, for example, when performing the slip control.

On the other hand, in a lock-up device, there is known a structure in which a tubular portion is provided on the outer periphery of a piston, and the tubular portion supports a load when the torsion spring tries to move radially outward due to centrifugal force. ing. In this structure, the rigidity of the annular portion on which the friction facing is stretched by the cylindrical portion is increased. An object of the present invention is to enhance the friction performance of a portion of a piston having a cylindrical portion extending in an axial direction formed on an outer peripheral edge thereof, the portion being frictionally connected to another member.

[0007]

The lock-up piston of the torque converter according to the present invention is disposed between the front cover of the torque converter and the turbine in the axial direction, and is movable in the axial direction by changing the hydraulic pressure. There is a piston that can be connected to an output member via a torsion spring. The piston includes a disk-shaped member, a retaining plate, and an annular member. The disk-shaped member has a disk-shaped portion and an annular portion formed on the outer peripheral side of the disk-shaped portion for frictionally engaging with another member. The retaining plate is a member that is fixed to the turbine-side surface of the annular portion and supports the torsion spring, and has a support portion that supports the torsion spring radially outside.
The annular member engages the outer peripheral surface of the support.

[0008] In the lock-up piston of the torque converter according to the first aspect, the annular member supports the load applied from the torsion spring by engaging with the outer peripheral surface of the support portion. Since this annular member is a member separate from the disk-shaped member, it does not affect the rigidity of the disk-shaped member. That is, the rigidity of the annular portion is lower than that of the conventional disk-shaped member. In this way, the load acting from the torsion spring is sufficiently supported, and the friction performance is improved by reducing the rigidity of the annular portion.

According to a second aspect of the present invention, in the first aspect, the support portion is an annular outer peripheral wall, and the annular member is tightly fitted to the support portion. In the lock-up piston of the torque converter according to the second aspect, the annular member is fixed to the support in a simple manner.

According to a third aspect of the present invention, there is provided a lock-up piston for a torque converter according to the second aspect, wherein an annular main body disposed radially outward of the support portion and first and second abutments on both axial sides of the support portion, respectively. A second contact portion. In the lock-up piston of the torque converter according to the third aspect, the movement of the annular member in the axial direction with respect to the support portion is restricted by the first contact portion and the second contact portion.

According to a fourth aspect of the present invention, in the third aspect, the first contact portion extends from the axial front cover side of the annular main body and contacts the support portion from the axial front cover side. It is a nail part. According to a fifth aspect of the present invention, in the lock-up piston for a torque converter according to the third aspect, the first contact portion is formed on the axial front cover side of the annular main body, and is caulked to contact the support portion from the axial front cover side. Department.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 is a partial longitudinal sectional view of a torque converter 61 which embodiment of the present invention is employed. Here, a sectional view of only the outer peripheral side portion of the torque converter 61 is shown. An engine (not shown) is arranged on the left side of FIG. 1, and a transmission (not shown) is arranged on the right side of FIG. R1 in FIG. 3 is the rotation direction of the torque converter 61 and the lockup device 1.

The torque converter 61 is a mechanism for transmitting torque from a crankshaft on the engine side to a main drive shaft of the transmission, and includes a front cover 62 fixed to an input side member, and three types of impellers. 63, a turbine 67, a stator) and a lock-up device 1. The front cover 62 is a disk-shaped member, and an outer peripheral cylindrical portion 66 protruding toward the transmission in the axial direction is formed on an outer peripheral portion of the front cover 62.
The outer peripheral cylindrical portion 66 is provided with the impeller shell 6 of the impeller 63.
4 Fixed to the outer peripheral edge by welding. Impeller 63
, A plurality of impeller blades 65 are fixed inside the impeller shell 64. The turbine 67 is disposed in the fluid chamber so as to face the impeller 63. The turbine 67 includes a turbine shell 68 and a plurality of turbine blades 69 fixed to a surface of the turbine shell 68 on the impeller side.

The lock-up device 1 includes a front cover 62
And in a space between the turbine 67 and the axial direction.
The lock-up device 1 has a disk shape as a whole, and divides the aforementioned space in the axial direction. The space between the front cover 62 and the lockup device 1 is defined as a first hydraulic chamber A,
The space between the lockup device 1 and the turbine 67 is
Hydraulic chamber B. At the time of disengagement of the clutch, hydraulic oil is supplied to the first hydraulic chamber A from the inner peripheral side, and the hydraulic oil flows outward in the radial direction, then flows to the second hydraulic chamber B, and further, the outlet of the impeller 63 and the inlet of the turbine 67. Flows into the torus space from the gap between the torus. At this time, since the hydraulic pressure in the first hydraulic chamber A becomes higher than the hydraulic pressure in the second hydraulic chamber B, the entire lockup device 1 moves to the axial transmission side (that is, the axial turbine 67 side), and the clutch connection is released. Have been. Subsequently, when the hydraulic oil in the first hydraulic chamber A is drained, the hydraulic pressure in the second hydraulic chamber B becomes higher than the hydraulic pressure in the first hydraulic chamber A, so that the lockup device 1 as a whole is located on the engine side in the axial direction (that is, on the axial side). (The front cover 62 side). As a result, the lock-up device 1 is pressed against the friction surface 70 of the front cover 62, and
Is input to the lock-up device 1.

The other parts of the torque converter 61 not shown in FIG. 1 have a structure common to ordinary torque converters. 2 to 4, the lock-up device 1 mainly includes a disk-shaped member 2, a retaining plate 3, a plurality of torsion springs 4, a driven plate 7, and an annular member 30. Have been.

The disk-shaped member 2 is a member for connecting / disconnecting the clutch, and further functions as an input member in the lock-up device 1. The disk-shaped member 2 has a disk shape with a center hole formed therein. The disk-shaped member 2 is made of a sheet metal material. The disk-shaped member 2 mainly includes a disk-shaped part 11 and an annular part 12 (friction connection part) formed on the outer peripheral side of the disk-shaped part 11. As is apparent from FIG. 2, the disk-shaped portion 11 is subjected to drawing processing having irregularities in the axial direction.
Further, an inner peripheral cylindrical portion 15 extending toward the transmission in the axial direction is formed on the inner peripheral edge of the disk-shaped portion 11. The inner peripheral cylindrical portion 15 is supported, for example, on an outer peripheral surface of a turbine hub (not shown) so as to be relatively rotatable and movable in the axial direction.

The annular portion 12 has an annular shape having a predetermined width in the radial direction, and has a planar shape in which both surfaces in the axial direction are surfaces perpendicular to the axial direction. A friction facing 6 is adhered to the front cover side of the annular portion 12. The friction facing 6 faces the friction surface 70 of the front cover 62. As described above, the annular portion 12 has an annular flat plate shape having a predetermined length in the radial direction, and has no projection or wall of any shape formed on the outer peripheral edge thereof. For this reason, the rigidity of the annular portion 12 is significantly reduced as compared with the conventional annular portion if the same material and the same plate thickness are used. For example, it is known by calculation that the rigidity is reduced to 20% as compared with the conventional case.

The retaining plate 3 is arranged on the transmission side of the annular portion 12 in the axial direction. The retaining plate 3 is an annular member made of sheet metal. The function of the retaining plate 3 is to hold a torsion spring 4 described later. Retaining plate 3
The main body portion 17 has an inner peripheral portion fixed to the disk-shaped member 2 by a plurality of rivets 5. On the outer peripheral edge of the main body 17,
A cylindrical portion 18 (support portion) extending toward the transmission in the axial direction is formed. The cylindrical portion 18 is an annular wall. The distal end portion of the cylindrical portion 18 is slightly bent radially inward. The outer peripheral side cut-and-bent portion 21 is formed in the cylindrical portion 18 at equal intervals in the circumferential direction. Outer side cutting and bending part 2
Reference numeral 1 denotes a portion obtained by cutting the tip of the cylindrical portion 18 inward and bending it.
It extends radially inward. Further, a first inner peripheral side cut-and-raised portion 22 is formed in the main body 17 corresponding to the outer peripheral side cut and bent portion 21. The first inner circumferential cut-and-raised portion 22 is a portion cut and raised from the main body portion 17 and extends toward the transmission in the axial direction. A hole 25 is formed in the main body 17 by the first inner circumferential cut-and-raised portion 22. Further, in the main body 17, second inner peripheral side cut-and-raised portions 19 are formed at positions corresponding to circumferential positions of the respective first inner peripheral side cut-and-raised portions 22. The second inner circumferential cut-and-raised portion 19 is cut and raised from the main body portion 17 and extends toward the transmission in the axial direction. A slit 20 is formed in the cylindrical portion 18 at a portion between the outer circumferential cutout bent portion 21 and the first inner circumferential cutout portion 22 in the circumferential direction, that is, at a portion corresponding to the second inner circumferential cutout portion 19. This slit 2
The circumferential width of 0 is smaller than the linear shape of the torsion spring 4 described later. Further, the slit 20 is connected to a hole 26 formed by cutting and raising the second inner circumferential side cutting and raising portion 19.

The torsion spring 4 is used for the disc-shaped member 2.
And the driven plate 7 are elastically connected in the rotation direction. Each torsion spring 4 is disposed between each pair of the first inner circumferential cut-and-raised portion 22 and the outer cut-out bent portion 21 of the retaining plate 3 in the circumferential direction. As a result, both ends in the circumferential direction of the torsion spring 4 are in contact with and supported by the outer-side cut-out bent portion 21 and the first inner-side cut-and-raised portion 22 as a torque transmission engaging portion. Further, the radially outer side of the torsion spring 4 is supported by a cylindrical portion 18 as an outer peripheral wall, and the radially inner side is supported by a second inner peripheral side cut-and-raised portion 19. In this manner, the torsion spring 4 is supported by the retaining plate 3 on both sides in the radial direction and on the engine side in the axial direction, and further on both ends in the circumferential direction.

Each torsion spring 4 is a coil spring composed of a combination of a large coil spring and a small coil spring. The small coil spring is disposed inside the large coil spring, and has a circumferential length shorter than that of the large coil spring. As a result, when the torsion spring 4 is compressed in the rotation direction, a two-stage torsional characteristic can be realized. Spring seats 9 are arranged at both circumferential ends of each torsion spring 4. The spring seat 9 is engaged with the outer peripheral side cut-and-bent portion 21, the first inner peripheral side cut-and-raised portion 22, and the claw 8 (described later) so as to be able to transmit torque.

The driven plate 7 is a disk-shaped member, and is disposed between the disk-shaped member 2 and the turbine 67 in the axial direction. The driven plate 7 has a claw 8 on an outer peripheral edge thereof that comes into contact with both circumferential ends of each torsion spring 4. The claw 8 extends in the axial direction from a gap between the outer peripheral cutout bent portion 21 and the first inner peripheral cutout portion 22. The driven plate 7 has an inner peripheral edge having an inner peripheral cylindrical portion 15 of the disc-shaped member 2.
It extends to the vicinity. The driven plate 7 has an inner peripheral portion fixed to a turbine hub (not shown). Further, the driven plate 7 may be of a type fixed to the turbine shell on the outer peripheral side.

The annular member 30 is arranged on the outer peripheral side of the cylindrical portion 18 of the retaining plate 3. The annular member 30 is a member for supporting the outer peripheral side of the cylindrical portion 18 to support the load acting on the radially outer side by the torsion spring 4. The whole annular member 30 is plate-shaped and cylindrical. The plate thickness of the annular member 30 is smaller than the plate thickness of the disk-shaped member 2. The annular member 30 has a main body 31 that comes into contact with the outer peripheral surface of the cylindrical portion 18. The main body 31 is tightly fitted to the cylindrical portion 18. An inclined portion 32 bent inward is formed on the axial transmission side of the main body 31, and further a tip portion 33 extending radially inward from the inclined portion 32.
Are formed. The inclined portion 32 is in contact with the slightly bent tip of the tubular portion 18, and the tip 33 is located on the axial transmission side of the tip of the tubular portion 18. Thus, the annular member 30 cannot move toward the engine side in the axial direction with respect to the retaining plate 3. Moreover,
A plurality of claws 34 are formed in the circumferential direction on the axial engine side of the main body 31. The claw 34 is bent inwardly and is in close contact with the surface of the cylindrical portion 18 on the engine side in the axial direction.

As described above, in the annular member 30, the inclined portion 32 and the tip portion 33 (second contact portion) abut on the axial transmission side of the cylindrical portion 18, and the pawl 34 (first contact portion). ) Is in contact with the cylinder portion 18 on the engine side in the axial direction. In other words, the annular member 30 is engaged with both surfaces in the axial direction of the cylindrical portion 18 and is not movable in the axial direction with respect to the cylindrical portion 18, that is, the retaining plate 3.

As described above, the annular member 30 for supporting the radially outward load from the torsion spring 4 is a member separate from the disk-shaped member 2. Are not in contact or engaged. Therefore, a structure that supports the load from the torsion spring 4 and does not increase the rigidity of the annular portion 12 is realized. The structure of the lockup device 1 will be described from another angle. The disk-shaped member 2, the retaining plate 3, the annular member 30 and the like form a piston 10 which is a member that rotates integrally. The piston 10 functions as an input member of the lockup device 1 as a damper. The driven plate 7 functions as an output member of the damper. The torsion spring 4 functions as an elastic member that connects the input member and the output member in the rotation direction in the damper.

Next, the operation will be described. The torque of the crankshaft from the engine is input to the front cover 62 via a flexible plate (not shown). As a result, the impeller 63 rotates and hydraulic oil flows from the impeller 63 to the turbine 67. The turbine 67 is rotated by the flow of the hydraulic oil, and the torque of the turbine 67 is output to a main drive shaft (not shown).

The speed ratio of the torque converter 61 increases,
When the rotation speed of the main drive shaft is constant, the first hydraulic chamber A between the disc-shaped member 2 and the front cover 62
Hydraulic fluid is drained through the interior of the main drive shaft. As a result, the disc-shaped member 2 is moved toward the front cover 62 due to the difference in hydraulic pressure between the first hydraulic chamber A and the second hydraulic chamber B. As a result, the friction facing 6 is pressed against the friction surface 70 of the front cover 62. As a result, the torque of the front cover 62 is
Is transmitted to the driven plate 7 via the retaining plate 3 and the torsion spring 4. Further, the torque is output from the driven plate 7 to a main drive shaft (not shown). That is, the front cover 62
Are mechanically connected to the turbine 67 and the front cover 6
2 is output directly to the main drive shaft (not shown) via the turbine 67.

At this time, the lock-up device 1 transmits torque and absorbs and attenuates torsional vibration input from the front cover 62. Specifically, when torsional vibration is input to the lock-up device 1 from the front cover 62, the torsion spring 4 is compressed between the retaining plate 3 and the driven plate 7. More specifically, the torsion spring 4 is compressed in the circumferential direction between the outer circumferential cutout bent portion 21 and the first inner circumferential cutout portion 22 and the claw 8 on the opposite side in the circumferential direction. After being compressed, the torsion spring 4 returns to its original state and repeats the above operations.

As described above, when the torsional vibration is input and the torsion spring 4 repeatedly compresses and expands, the torsion spring 4 moves radially outward by centrifugal force, and the cylindrical portion 18 of the retaining plate 3 And is sliding. That is, a force acts on the cylindrical portion 18 from the inside in the radial direction. The portion corresponding to the torsion spring 4 in the cylindrical portion 18 is divided into two in the circumferential direction by the slit 20. For this reason, the concentration of stress when receiving a force is reduced. As a result, the life of the retaining plate 3 can be maintained longer even if the plate thickness is made thinner than in the past. That is, the weight of the lockup device 1 is reduced.

The outer peripheral side of the cylindrical portion 18 is supported by an annular member 30. That is, the radial load applied from the torsion spring 4 is supported by the annular member 30 via the cylindrical portion 18. As described above, the annular member 30 supports the load applied from the torsion spring 4 by engaging with the outer peripheral surface of the cylindrical portion 18. Since this annular member 30 is a member separate from the disk-shaped member 2 (it rotates integrally but does not have a continuous portion),
It hardly affects the rigidity of the disk-shaped member 2. That is, the rigidity of the annular portion 12 is lower than that of a conventional disk-shaped member (having a cylindrical portion extending in the axial direction from the outer peripheral edge of the annular portion). In this way, the load acting from the torsion spring 4 is sufficiently supported, and the rigidity of the annular portion 12 is reduced to improve the friction performance.

Second Embodiment In the lock-up device 1 shown in FIGS. 5 and 6, an annular member 37 is tightly fitted on the outer peripheral surface of the cylindrical portion 18. The effect obtained by this annular member 37 is the same as in the above-described embodiment. The main body 38 of the annular member 37 has a cylindrical shape and is in close contact with the outer peripheral surface of the cylindrical portion 18. In this embodiment, the thickness of the main body 38 is substantially the same as the thickness of the disc-shaped member 2. On the transmission side of the body 38 in the axial direction, an engaging portion 39 protruding inward is formed. The engagement portion 39 is the cylindrical portion 1
8 is in contact with the bent tip. Also, body 3
A caulking portion 40 is formed on the inner peripheral side of the engine 8 in the axial direction. A plurality of caulking portions 40 are formed side by side in the circumferential direction. The caulked portion 40 protrudes from the main body 38 toward the inner peripheral side, and is strongly pressed against the cylinder portion 18 toward the engine in the axial direction. Thus, the annular member 37
Since the engaging portion 39 and the caulking portion 40 abut on both sides in the axial direction of the cylindrical portion 18, it is difficult to move in the axial direction with respect to the cylindrical portion 18.

[0031]

According to the lock-up piston of the torque converter according to the present invention, since the annular member is a member separate from the disk-shaped member, it does not affect the rigidity of the disk-shaped member. The rigidity of the annular portion is lower than that of the plate-like member. In this way, the load acting from the torsion spring is sufficiently supported, and the friction performance is improved by reducing the rigidity of the annular portion.

[Brief description of the drawings]

FIG. 1 is a schematic partial longitudinal sectional view of a torque converter employing a lock-up clutch as a first embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional view of a lock-up device.

FIG. 3 is a plan view of the lockup device.

FIG. 4 is a partial instruction of a lock-up device.

FIG. 5 is a schematic longitudinal sectional view of a lockup device according to a second embodiment.

FIG. 6 is a plan view of a lockup device according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lock-up apparatus 2 Disc-shaped member 3 Retaining plate 4 Torsion spring 10 Piston 11 Disc-shaped part 12 Annular part 18 Tubular part 30 Annular member

Claims (5)

[Claims] 1. A piston which is disposed between a front cover of a torque converter and a turbine in an axial direction, is movable in an axial direction by a change in oil pressure, and is connectable to an output member via a torsion spring. A disk-shaped member having a plate-shaped portion and an annular portion formed on the outer peripheral side of the disk-shaped portion for frictionally engaging with another member; and the disk-shaped member being fixed to a surface of the annular portion on the turbine side. A torque converter comprising: a member for supporting a torsion spring; and a retaining plate having a support portion for supporting a radially outer side of the torsion spring; and an annular member engaged with an outer peripheral surface of the support portion. Lock-up piston. 2. The torque converter lock-up piston according to claim 1, wherein said support portion is an annular outer peripheral wall, and said annular member is tightly fitted to said support portion. 3. The annular member has an annular main body disposed radially outward of the support portion, and first and second contact portions that respectively contact axially opposite sides of the support portion. ,
A lock-up piston for the torque converter according to claim 2. 4. The torque converter lock according to claim 3, wherein said first contact portion is a claw portion extending from an axial front cover side of said annular body and abutting against said support portion from said axial front cover side. Up piston. 5. The torque converter according to claim 3, wherein the first contact portion is a caulked portion formed on the axial front cover side of the annular body and abutting on the support portion from the axial front cover side. Lock-up piston.