Patent Publication Number: US-11384824-B2

Title: Lock-up device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2020-095659, filed Jun. 1, 2020. The entire contents of that application are incorporated by reference herein in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to a lock-up device, particularly to a lock-up device for a torque converter transmitting a torque from a front cover to a transmission side member through a turbine. 
     BACKGROUND ART 
     A Torque converter is often provided with a lock-up device for transmitting torque directly from the front cover to a turbine. This lock-up device has a piston that can be frictionally connected to the front cover, an input side plate that is fixed to the piston, multiple torsion springs that are supported by the input side plate, and an output side plate that is elastically connected with the piston and the input side plate in the direction of rotation. The output side plate is fixed to the turbine. 
     In the lock-up device shown in Japan Laid-open Patent Application Publication No. 2017-166669 and Japan Laid-open Patent Application Publication No. 2013-217452, an oil chamber for operating the piston is configured between the piston and the turbine. The oil chamber is composed of a piston and an oil chamber plate. The oil chamber plate is fixed to the sleeve of the lock-up device. The oil chamber plate receives high oil pressure not only from the oil chamber but also from the turbine side. Therefore, high strength is required for the part where the oil chamber plate is fixed to the sleeve. 
     In the lock-up device illustrated in Japan Laid-open Patent Application Publication No. 2017-166669 and Japan Laid-open Patent Application Publication No. 2013-217452, the oil chamber plate is fixed to the sleeve by welding. 
     BRIEF SUMMARY 
     When an oil chamber plate is fixed to a sleeve by welding, lap welding is often used. In the case of this lap welding, the amount of heat required to secure the penetration is large. Therefore, the member is distorted. In particular, in a sleeve, a part that movably supports a piston is provided near a part where an oil chamber plate is fixed. High precision is required for the part that supports this piston. However, when lap welding is performed, distortion may occur in this part as well, and high accuracy may not be obtained. 
     Further, when an oil chamber plate is fixed to a sleeve by welding, it is necessary to suppress generation of welding beads. 
     It is an object of the present invention that welding can be performed with a low amount of heat and generation of welding beads is suppressed in a lock-up device, in which an oil chamber is formed by an oil chamber plate, when the oil chamber plate is fixed by welding. 
     (1) A lock-up device according to the present invention is a lock-up device for a torque converter transmitting a torque from a front cover to a transmission-side member through a turbine of the torque converter. The lock-up device comprises a clutch part, a piston, a sleeve, and an oil chamber plate. The clutch part is disposed between the front cover and the turbine. The piston is movably provided in an axial direction, and the piston brings clutch part into a torque transmission state. The sleeve is fixed to the inner peripheral part of the front cover. The sleeve has a piston support part and a first butt part. The piston support part supports an inner peripheral surface of the piston to be movable in an axial direction. The first butt part is annular and is formed on the outer peripheral surface. The oil chamber plate is provided between the piston and the turbine. The annular oil chamber plate has a second butt part on an inner peripheral surface. The second butt part is butt-welded in contact with the first butt part. The annular oil chamber plate forms an oil chamber, the oil chamber a hydraulic fluid being supplied between the oil chamber and the piston. 
     In this lock-up device, a sleeve and an oil chamber plate have a butt part. That is, the oil chamber plate is fixed to the sleeve by butt welding. Therefore, as compared with lap welding, it is possible to realize the penetration of the member with a lower amount of heat, and it is possible to reduce the distortion of the member. In addition, generation of welding beads can be suppressed. 
     (2) Preferably, the sleeve has a first engaging part. The first engaging part is provided on the front cover side of the first butt part on the outer peripheral surface of the sleeve. The first engaging part is an annular member having a diameter smaller than that of the first butt part. The oil chamber plate has a second engaging part. The second engaging part is provided on the oil chamber side of the second butt part on the inner peripheral surfaces of the oil chamber plate. The second engaging part has a diameter smaller than that of the second butt part and engages with the first engaging part. 
     In this case, the sleeve and the oil chamber plate each have an engaging part. In this case, the oil chamber plate can be supported by the sleeve by the engaging part even when the oil chamber plate receives the oil pressure from the Torque converter side. Therefore, the strength of the welded part can be further strengthened. 
     (3) Preferably, the front cover has a circular opening in the center. The sleeve further has a welded part inserted into the opening of the front cover and laser welded. 
     (4) Preferably, the sleeve has an oil passage to provide hydraulic fluid to the oil chamber. An opening of the oil passage is formed between the piston support part and the first butt part in an axial direction. 
     In this case, an oil passage opening is provided between the piston support part and the first butt part in an axial direction. That is, the piston support part that requires high precision on the outer peripheral surface and the first butt part that is welded (that is, exposed to high heat) are axially separated from each other. Therefore, it is possible to prevent the outer peripheral surface of the piston support part (that is, the piston support surface) from being affected by heat and the accuracy from being lowered. 
     In the present invention as described above, in the lock-up device in which the oil chamber is formed by the oil chamber plate, when the oil chamber plate is fixed by welding, welding can be performed with a low amount of heat and the generation of welding beads can be suppressed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-partial view of a torque converter provided with a lock-up device according to an embodiment of the present invention. 
         FIG. 2  is a figure which extracts and shows the lock-up device of  FIG. 1 . 
         FIG. 3  is a perspective view of a damper part according to an embodiment of the present invention. 
         FIG. 4  is a front view of a damper part according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a partial cross-partial view of a torque converter  1  having a lock-up device  4  according to an embodiment of the present invention. An engine (not illustrated) is provided on the left side of  FIG. 1 , and a transmission (not illustrated) is provided on the right side of the figure. The O-O illustrated in  FIG. 1  is a rotation axis of the torque converter  1  and the lock-up device  4 . Further, in the following, the direction away from the rotation axis is referred to as a “radial direction”, and the direction along the rotation axis is referred to as an “axial direction”. 
     [Entire Configuration of Torque Converter  1 ] 
     The torque converter  1  is a device for transmitting torque from a crankshaft (not illustrated) on the engine side to an input shaft of a transmission. As illustrated in  FIG. 1 , a torque converter  1  includes a front cover  2 , a torque converter main body  3 , and the lock-up device  4 . 
     The front cover  2  is fixed to the member on the input side. The front cover  2  is a substantially disc-shaped member, and has a disc part  2   a  and an outer peripheral tubular part  2   b  formed on the outer peripheral part of the disc part  2   a  so as to project toward the transmission side. 
     [Torque Converter Main Body  3 ] 
     The torque converter main body  3  has an impeller  10 , a turbine  11 , and a stator  12 . The impeller  10  has an impeller shell  15  fixed to the outer peripheral tubular part  2   b  of the front cover  2  by welding. The turbine  11  is provided in a fluid chamber so as to face the impeller  10 . The turbine  11  has a turbine shell  16  that constitutes an outer shell. A turbine hub  17  is provided on the inner peripheral part of the turbine shell  16 . The turbine hub  17  has a hub  17   a  provided at the center and a flange  17   b  extending radially outward from the outer circumference of the hub  17   a . The flange  17   b  is fixed to the inner peripheral part of the turbine shell  16  by a rivet  18 . Further, a spline hole  17   c  with which an input shaft (not illustrated) of the transmission is engaged is formed in the inner peripheral part of the hub  17   a . The stator  12  is provided between the inner peripheral parts of the impeller  10  and the turbine  11  and rectifies the hydraulic fluid returning from the turbine  11  to the impeller  10 . The stator  12  is supported by a fixed shaft via a one-way clutch  20 . A first thrust bearing  21  and a second thrust bearing  22  are provided between the stator  12  and the impeller  10 ; and the stator  12  and the turbine hub  17 , respectively. 
     [Lock-Up Device  4 ] 
     As illustrated in  FIGS. 1 and 2 , the lock-up device  4  is provided in the space between the front cover  2  and the torque converter main body  3 . The lock-up device  4  transmits torque from the front cover  2  to the member on the transmission side via the turbine  11  of the torque converter  1 . The lock-up device  4  includes a clutch part  24 , a clutch operating part  27  including a piston  25 , and a damper part  28 . 
     &lt;Clutch Part  24 &gt; 
     As illustrated in  FIGS. 1 and 2 , the clutch part  24  is provided between the front cover  2  and the turbine  11 . Clutch part  24  transmits or block torque. 
     Clutch part  24  is a multi-plate type clutch. Clutch part  24  has an inner peripheral drum  30 , an outer peripheral drum  31 , and a plurality of first clutch plates  32  and second clutch plates  33 , respectively. 
     The inner peripheral drum  30  has a fixed part  30   a  and an inner peripheral tubular part  30   b . The fixing part  30   a  is formed of a disk in an annular shape, and is fixed to the side surface of the front cover  2  by welding. The inner peripheral tubular part  30   b  is formed by bending the outer peripheral part of the fixed part  30   a  toward the turbine  11 . A plurality of grooves are formed in the inner peripheral tubular part  30   b  at predetermined intervals in the circumferential direction. 
     The outer peripheral drum  31  has a connecting part  31   a  and an outer peripheral tubular part  31   b . The connecting part  31   a  is formed of a disk in an annular shape. The outer peripheral tubular part  3 l b  is formed by bending the inner peripheral part of the connecting part  31   a  toward the front cover  2 . The outer peripheral tubular part  31   b  is provided so as to face the inner peripheral tubular part  30   b  of the inner peripheral drum  30  in the radial direction. A plurality of grooves are formed in the outer peripheral tubular part  31   b  at predetermined intervals in the circumferential direction. 
     The plurality of first clutch plates  32  and the second clutch plates  33  are formed in a disk shape and are provided alternately in the axial direction. A plurality of teeth are formed on the inner peripheral part of the first clutch plate  32 , and are slidably engaged with the groove of the inner peripheral tubular part  30   b  of the inner peripheral drum  30 . Therefore, the first clutch plate  32  cannot rotate relative to the inner peripheral drum  30 , and is movable in the axial direction. Further, the second clutch plate  33  has a friction material fixed on both sides. A plurality of teeth are formed on the outer peripheral part of the second clutch plate  33 , and are slidably engaged with the groove of the outer peripheral tubular part  31   b  of the outer peripheral drum  31 . Therefore, the second clutch plate  33  cannot rotate relative to the outer peripheral drum  31 , and is movable in the axial direction. 
     &lt;Clutch Operating Part  27 &gt; 
     The clutch operating part  27  is a mechanism for turning the clutch part  24  on (lock-up on state, that is, power transmission state) or off (lock-up off state, that is, power transmission release state), and includes a piston  25 , a sleeve  35 , and an oil chamber plate  36 . 
     —Piston  25 — 
     The piston  25  is formed in an annular shape and is provided on the transmission side of the front cover  2 . The piston  25  is supported by the sleeve  35  so as to be movable in the axial direction. The piston  25  puts the clutch part into a torque transmission state. 
     The piston  25  has a disk part  25   a , an inner peripheral tubular part  25   b , and an outer peripheral tubular part  25   c . The outer peripheral part of the disk part  25   a  bulges toward the front cover  2  side, and can press the first clutch plate  32  of the clutch part The inner peripheral tubular part  25   b  is formed so as to project from the inner peripheral end part of the disc part  25   a  toward the front cover  2 . The outer peripheral tubular part  25   c  is formed so as to project from the outer peripheral end part of the disk part  25   a  toward the turbine  11 . 
     —Sleeve  35 — 
     The sleeve  35  is a member extending in the axial direction and has a space in the center. The engine side of the sleeve  35  is inserted into the inner peripheral opening Q of the front cover  2  and fixed to the front cover  2  by welding. Further, the sleeve  35  has a piston support part  35   a , a first butt part  35   b , a first engaging part  35   c , and a welded part on the turbine  11  side of the front cover  2 . 
     The piston support part  35   a  supports the inner peripheral surface of the piston  25  so as to be movable in the axial direction on the outer peripheral surface. The first butt part  35   b  is formed in an annular shape on the outer peripheral surface of the piston support part  35   a  on the turbine  11  side. The first engaging part  35   c  is formed on the piston support part  35   a  side of the first butt part  35   b  adjacent to the first butt part  35   b . The first engaging part  35   c  is annular and has a smaller diameter than the first butt part  35   b . That is, a step is formed between the first butt part  35   b  and the first engaging part  35   c . The welded part is laser welded. 
     —Oil Chamber Plate  36 — 
     The oil chamber plate  36  has a disk shape. The oil chamber plate  36  is provided between the piston  25  and the turbine  11 . The oil chamber plate  36  forms an oil chamber C, to which a hydraulic fluid is supplied, between itself and the piston  25 . A seal member  38  is provided on the outer peripheral surface of the piston support part  35   a , and the space between the piston support part  35   a  and the inner peripheral tubular part  25   b  of the piston  25  is sealed. Further, a sealing member  39  is provided on the outer peripheral surface of the oil chamber plate  36 , and the space between the oil chamber plate  36  and the outer peripheral tubular part  25   c  of the piston  25  is sealed. With these configurations, the oil chamber C is sealed. 
     Here, the disk part  25   a  of the piston  25  is provided with a plurality of concave part  25   d  concaved on the front cover  2  side. Further, the oil chamber plate  36  is provided with a plurality of convex parts  36   a  that are inserted into and engaged with the concave part  25   d  of the piston  25 . Therefore, the piston  25 , the oil chamber plate  36 , and the front cover  2  cannot rotate relative to each other, so they rotate integrally with each other. 
     The oil chamber plate  36  has a second butt part  36   b  and a second engaging part  36   c  on the inner peripheral surface. The second butt part  36   b  is in contact with the first butt part  35   b  of the sleeve  35  and is butt welded. The second engaging part  36   c  is annular and is formed on the oil chamber side of the second butt part  36   b . The second engaging part  36   c  has a smaller diameter than the second butt part  36   b.    
     In such a configuration, since the sleeve  35  and the oil chamber plate  36  are butt-welded, both members  35  and  36  can be connected with a lower amount of heat and also beads are reduced as compared with welding by other lap welding or the like. 
     Further, on the oil chamber side of each of the butt parts  35   b  and  36   b , a first engaging part  35   c  and a second engaging part  36   c  having a diameter smaller than that of the butt parts  35   b  and  36   b  are provided, and these engaging parts  35   c  and  36   c  are engaged. Therefore, even if the oil pressure of the oil chamber C becomes high and the oil chamber plate  36  is pressed toward the turbine  11 , the second engaging part  36   c  of the oil chamber plate  36  is supported by the first engaging part  35   c  of the sleeve  35 , so the joint strength between the sleeve  35  and the oil chamber plate  36  can be maintained high. 
     —Oil Channel— 
     A first oil passage P 1  and a second oil passage P 2  are formed in the sleeve  35 . 
     The first oil passage P 1  connects the inner circumference of the sleeve  35  and the oil chamber C. The radial outer opening of the first oil passage P 1  is formed between the outer peripheral surface of the piston support part  35   a  and the first butt part  35   b  in the axial direction. Here, an opening of the first oil passage P 1  is provided between the piston support part  35   a  and the first butt part  35   b  in the axial direction. That is, the piston support part  35   a , which requires high precision on the outer peripheral surface, and the first butt part  35   b  to be welded (that is, exposed to high heat) are axially separated from each other. Therefore, it is possible to prevent the outer peripheral surface (that is, the piston support surface) of the piston support part  35   a  from being affected by heat and the accuracy from being lowered. 
     The second oil passage P 2  connects the inner circumference of the sleeve  35  and the space between the front cover  2  and the piston  25 . 
     &lt;Damper Part  28 &gt; 
     The Damper part  28  is provided on the outer peripheral side part of the lock-up device  4 . The damper part  28  transmits torque from the clutch part  24  to the turbine  11 , and absorbs and dampens torsional vibration. 
     As illustrated in  FIGS. 1 to 4 , the damper part  28  has a retaining plate  45  fixed to the connecting part  31   a  of the outer drum  31 , a plurality of torsion springs  46 , a driven plate  47 , and a support plate  50 . 
     —Retaining Plate  45  (Input Member)— 
     The retaining plate  45  is formed in a disk shape. The retaining plate  45  is provided between the front cover  2  and the driven plate  47  in the axial direction. The retaining plate  45  is connected to the clutch part  24 . The retaining plate  45  supports a plurality of torsion springs  46  in the axial direction and the radial direction, and is engaged with the plurality of torsion springs  46  in the rotational direction. 
     The retaining plate  45  has an input side connecting part  451 , an accommodating part  452 , and a facing part  453 . 
     The input side connecting part  451  is a part on the inner peripheral side of the retaining plate  45 . The input side connecting part  451  is fixed to the connecting part  31   a  of the clutch part  24  by a rivet  19 . 
     The plurality of accommodating parts  452  have a C-shaped cross section that bulges toward the front cover  2 . The accommodating part  452  further extends from the outer peripheral side end of the input side connecting part  451  to the outer peripheral side. The plurality of accommodating parts  452  are provided side by side in the circumferential direction, and a torsion spring  46  is accommodated therein. In the present embodiment, the number of accommodating parts  452  is three. 
     The facing part  453  is formed so as to extend from the end part on the inner peripheral side of the input side connecting part  451  toward the turbine  11  side, and the tip thereof can come into contact with the driven plate  47 . 
     —Driven Plate  47 — 
     The driven plate  47  has a substantially disk shape and is rotatable relative to the retaining plate  45 . 
     The driven plate  47  has a disk part  471 , an output side support part  472 , and a plurality of engaging parts  473 . 
     The inner peripheral part of the disk part  471  is fixed to the outer peripheral part of the turbine shell  16  of the turbine  11  and the turbine hub  17  by the rivet  18 . 
     The output side support part  472  is formed in a tubular shape having a predetermined width in the axial direction in the radial intermediate part of the disk part  471 . 
     The plurality of engaging parts  473  are formed so as to extend outward in the radial direction from the outer peripheral end part of the disc part  471 . The outer periphery of the engaging part  473  is bent toward the retaining plate  45 . This bent part is engaged with the end face of the torsion spring  46 . 
     —Torsion Spring  46 — 
     The plurality of torsion springs  46  are accommodated in the accommodating part  452  of the retaining plate  45 . In this embodiment, the number of torsion springs  46  is three. 
     The torsion spring  46  elastically connects the retaining plate  45  and the driven plate  47  in the rotational direction. 
     The circumferential end of the torsion spring  46  engages the outer peripheral part of the engaging part  473  of the driven plate  47 . 
     —Support Plate  50 — 
     The support plate  50  has a substantially disk shape, and has a plurality of connecting parts  51  (support parts), a regulating part  52  (annular part), and a plurality of stopper parts  53  (contact parts). 
     A plurality of connecting parts  51  are disposed between the retaining plate  45  and the driven plate  47  in the axial direction. Each connecting part  51  is connected to the retaining plate  45  by the rivet  19 . 
     The regulating part  52  is formed in an annular shape and is provided between the driven plate  47  and the turbine  11 . The regulating part  52  is provided to sandwich the driven plate  47  between it and a part of the retaining plate  45  in the axial direction. The regulating part  52  is axially faced to the facing part  453  of the retaining plate  45 . Further, the inner peripheral end surface of the regulating part  52  is supported by the output side supporting part  472  of the driven plate  47 . As a result, the support plate  50  is radially positioned by the driven plate  47 . 
     The stopper part  53  is provided between the plurality of connecting parts  51  and the regulating part  52  so as to connect them. The circumferential length of the stopper part  53  is shorter than the circumferential length of the connecting part  51 . More specifically, the stopper part  53  is formed so as to extend from the radially inner end part of the connecting part  51  toward the turbine  11  side in the axial direction. The regulating part  52  extends radially inward from the end part on the turbine  11  side in the axial direction of the stopper part  53 . The stopper part  53  is a part where the support plate  50  and the driven plate  47  intersect in the axial direction. 
     The stopper part  53  can come into contact with the inner peripheral part (more specifically, the end face in the circumferential direction of the engaging part  473 ) of the engaging part  473  of the driven plate  47 . The stopper part  53  prohibits the retaining plate  45  and the driven plate  47  from rotating relative to each other by a predetermined angle or more. 
     The support plate  50  further has a plurality of support parts  54 . The support part  54  is provided on the outer peripheral part of the connecting part  51 . The support part  54  is a part in which the outer peripheral part of the connecting part  51  is bent toward the turbine  11 . The support part  54  supports the inner peripheral surface of the torsion spring  46 . In the present embodiment, the number of support parts  54  is three. 
     The circumferential length of each of the plurality of support parts  54  is longer than the circumferential length of the stopper part  53 , as described above. The circumferential length of each of the plurality of support parts  54  is 30% or more of the circumferential length of the elastic member. 
     [Actions] 
     First, the operation of the torque converter main body  3  will be described. When the front cover  2  and the impeller  10  are rotating, the hydraulic fluid flows from the impeller  10  to the turbine  11 , and further flows to the impeller  10  via the stator  12 . As a result, torque is transmitted from the impeller  10  to the turbine  11  via hydraulic fluid. The torque transmitted to the turbine  11  is transmitted to the input shaft of the transmission via the turbine hub  17 . 
     When the speed ratio of the torque converter  1  increases and the input shaft reaches a determined rotation speed, the hydraulic fluid is supplied to the oil chamber C via the first oil passage P 1 . Also hydraulic fluid in the space between the front cover  2  and the piston  25  is discharged through the second oil passage P 2 . As a result, the piston  25  moves to the front cover  2  side. As a result, the pressing part of the piston  25  presses the first clutch plate  32  and the second clutch plate  33  against the side surface of the front cover  2  to enter a lock-up state (clutch-on state). 
     In the clutch-on state as described above, the torque is transmitted from the front cover  2  to the torque converter main body  3  via the Lock-up device  4 . That is, the torque input to the front cover  2  is output to the turbine hub  17  via the clutch part  24  and the damper part  28 . In this clutch-on state, the torque fluctuation is attenuated by damper part  28  of the lock-up device  4 . 
     [Features] 
     When the lockup is turned off (clutch off state) from the lockup state, the oil chamber C is connected to the drain. As a result, the hydraulic fluid oil chamber C is discharged through the first oil passage P 1 . Then, the piston  25  moves to the turbine  11  side, and the pressure of the piston  25  on the first clutch plate  32  and the second clutch plate  33  is released. As a result, the clutch is off. 
     In the lock-up device  4 , the sleeve  35  and the oil chamber plate  36  have butt parts  35   b  and  36   b . That is, the oil chamber plate  36  is fixed to the sleeve  35  by butt welding. Therefore, the sleeve  35  and the oil chamber plate  36  can be welded with a lower amount of heat as compared with the case where they are fixed by lap welding, and the generation of welding beads can be suppressed. 
     In this lock-up device  4 , a support plate  50  is provided separately from the member to which the torsion spring  46  is attached, and the support plate  50  supports the inner peripheral surface of the torsion spring  46 . Therefore, in the retaining plate  45 , it is not necessary to form a cut-up part or the like on the member to which the torsion spring  46  is attached, and the strength of the member to which the torsion spring  46  is attached does not decrease. Further, since the support plate  50  is a separate member, the circumferential length of the part supporting the torsion spring  46  can be increased. As a result, operation of the torsion spring  46  is stabilized. 
     In this lock-up device  4 , the driven plate  47  is sandwiched between a pair of input side members (retaining plate  45  and support plate  50 ), so that they cannot move relative to each other in the axial direction. Further, in the lock-up device  4 , the support plate  50  and the driven plate  47  are brought into contact with each other in the circumferential direction to form a stopper mechanism for regulating the twisting angle. That is, the stopper mechanism is composed of the support plate  50  and the driven plate  47 , which cannot move relative to each other in the axial direction. Therefore, the problem in the conventional stopper mechanism, that is, the disengagement between the claw and the engagement hole (disengagement of the stopper mechanism) is eliminated. 
     Other Preferred Embodiments 
     The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention. 
     (a) In the above embodiment, on the outer circumference of the sleeve  35 , each butt portion  35   b ,  36   b  was disposed on the turbine  11  side and each engagement portion  35   c ,  36   c  was disposed on the front cover  2  side, but these can be reversed. In other words, each of the butt portions  35   b ,  36   b  can be placed on the front cover  2  side and each of the engagement portions  35   c ,  36   c  can be placed on the turbine  11  side. 
     (b) The first engaging part  35   c  and the second engaging part  36   c  need only contact each other in the axial direction on each side face, and the outer surface of the first engagement portion  35   c  and the inner surface of the second engagement portion  36   c  can be in contact with each other or can be separated from each other. 
     (c) In the above embodiment, the support plate  50  and the retaining plate  45  are made immovable relative to each other in the axial direction, and the stopper mechanism is formed by these plates, but the member on the input side is not limited to the support plate  50 , and the member on the output side is not limited to the retaining plate  45 . If the input side member and the output side member are made relatively immovable in the axial direction and the stopper mechanism is configured by them, the same operation and effect as those of the above-described embodiment can be obtained. 
     (d) The configuration of the stopper part  53  of the support plate  50  is not limited to the above embodiment. For example, the stopper part  53  can be formed by bending a part of the support plate  50  in the axial direction. 
     (e) The configuration of the clutch part  24  and the damper part  28  is not limited to the above embodiment. For example, the present invention can be applied in the same way to a single plate type clutch part  24 . Further, the present invention can be similarly applied to the lock-up device  4  in which the damper part  28  is not provided. 
     REFERENCE SIGNS LIST 
     
         
           1  Torque converter 
           2  Front cover 
           4  Lock-up device 
           24  Clutch part 
           25  Piston 
           35  Sleeve 
           35   a  Piston support part 
           35   b  First butt part 
           35   c  First engaging part 
           36  Oil chamber plate 
           36   b  Second butt part 
           36   c  Second engaging part 
         C Oil chamber 
         P 1  First oil passage