Patent Publication Number: US-2023150349-A1

Title: Vehicle drive device

Description:
TECHNICAL FIELD 
     The present disclosure relates to a vehicle drive device including an input member drivingly connected to an internal combustion engine, an output member drivingly connected to wheels, a rotary electric machine that functions as a driving force source for the wheels, a transmission that changes the speed of rotation transmitted from the rotary electric machine side and transmits the rotation to the output member side, and a case that houses the rotary electric machine and the transmission. 
     BACKGROUND ART 
     An example of such a vehicle drive device is disclosed in Patent Document 1 below. In the following descriptions of “Background Art” and “Problem to be Solved by the Invention”, reference numerals in Patent Document 1 are quoted in parentheses. 
     The vehicle drive device of Patent Document 1 includes a first bearing ( 51 ) that supports a rotor support member ( 3 ) that supports a rotor (Ro) of a rotary electric machine (MG) so that the rotor support member ( 3 ) is rotatable relative to a case ( 2 ), and a second bearing ( 53 ) that supports an input member (I) so that the input member (I) is rotatable relative to the case ( 2 ). Each of these bearings ( 51 ,  53 ) is directly supported on the case ( 2 ). 
     RELATED ART DOCUMENTS 
     Patent Documents 
     Patent Document 1: WO 2019/187597 ( FIG.  4   ) 
     SUMMARY OF THE DISCLOSURE 
     Problem to be Solved by the Disclosure 
     In the above configuration, portions of the case ( 2 ) for supporting the two bearings ( 51 ,  53 ) are arranged side by side in a radial direction (R). Therefore, the size of the vehicle drive device in the radial direction (R) tends to increase. 
     In view of the above, it is desirable to realize a vehicle drive device whose radial dimension can be reduced easily. 
     Means for Solving the Problem 
     As the characteristic configuration of the vehicle drive device in view of the above, the vehicle drive device includes: 
     an input member drivingly connected to an internal combustion engine; 
     an output member drivingly connected to a wheel; 
     a rotary electric machine including a rotor and functioning as a driving force source for the wheel; 
     a transmission configured to change a speed of rotation transmitted from the rotary electric machine side and transmit the rotation to the output member side; and 
     a case that houses the rotary electric machine and the transmission, in which 
     the input member or a member that rotates integrally with the input member is defined as a first rotary member, and the rotor or a member that rotates integrally with the rotor is defined as a second rotary member, 
     the vehicle drive device includes:
     a first bearing that supports the second rotary member on the first rotary member so that the second rotary member rotates relative to the first rotary member; and   

     a second bearing that supports the first rotary member on the case so that the first rotary member rotates relative to the case, 
     the case includes a support that supports the second bearing, 
     the first rotary member has a support outer peripheral surface that faces an outer side in a radial direction, and a first radial support surface that faces one side in the radial direction, 
     the second rotary member has a support inner peripheral surface that faces an inner side in the radial direction, 
     the support has a second radial support surface that faces the first radial support surface in the radial direction, 
     the first bearing is arranged between the support outer peripheral surface and the support inner peripheral surface in the radial direction, 
     the second bearing is arranged between the first radial support surface and the second radial support surface in the radial direction, and 
     the first bearing is arranged on the inner side in the radial direction with respect to the rotor at a position where the first bearing overlaps the rotor in a radial view along the radial direction. 
     According to this characteristic configuration, the second rotary member is supported so as to be rotatable relative to the case via the first bearing, the first rotary member, and the second bearing. Therefore, the second radial support surface for supporting the second bearing is formed on the case, whereas a surface for supporting the first bearing is not formed on the case. The support outer peripheral surface for supporting the first bearing is formed on the first rotary member. Thus, it is possible to avoid a configuration in which a portion for supporting the first bearing and a portion for supporting the second bearing are arranged side by side in the radial direction on the case. 
     As a result, it is easy to reduce the radial dimension of the vehicle drive device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic view showing a schematic configuration of a vehicle drive device according to a first embodiment. 
         FIG.  2    is a partial sectional view of the vehicle drive device according to the first embodiment. 
         FIG.  3    is a partially enlarged sectional view of the vehicle drive device according to the first embodiment. 
         FIG.  4    is a partial sectional view of a vehicle drive device according to a second embodiment. 
         FIG.  5    is a partially enlarged sectional view of the vehicle drive device according to the second embodiment. 
         FIG.  6    is a partial sectional view of a vehicle drive device according to another embodiment. 
     
    
    
     MODES FOR CARRYING OUT THE INVENTION 
     1. First Embodiment 
     Hereinafter, a vehicle drive device  100  according to an embodiment will be described with reference to the drawings. The vehicle drive device  100  according to the present embodiment is mountable on an FF (front engine-front drive) vehicle. 
     As shown in  FIG.  1   , the vehicle drive device  100  is a device for driving a vehicle (hybrid vehicle) using either one or both of an internal combustion engine EG and a rotary electric machine MG as a driving force source for wheels W. That is, the vehicle drive device  100  is structured as a drive device for a so-called one-motor parallel hybrid vehicle. 
     In the following description, unless otherwise specified, an “axial direction L”, a “radial direction R”, and a “circumferential direction” are defined with reference to a rotation axis of the rotary electric machine MG. In the axial direction L, the side where the rotary electric machine MG is arranged with respect to the internal combustion engine EG will be referred to as “first side L 1  in axial direction”, and the opposite side will be referred to as “second side L 2  in axial direction”. In the radial direction R, the rotation axis side of the rotary electric machine MG will be referred to as “inner side R 1  in radial direction”, and the opposite side will be referred to as “outer side R 2  in radial direction”. The direction of each member represents a direction of the member that is assembled to the vehicle drive device  100 . In addition, terms related to the direction, the position, and the like of each member represent concepts that include a state in which there is a difference due to an error that is allowed in manufacturing. 
     The rotary electric machine MG functions as a driving force source for the wheels W. The rotary electric machine MG includes a stator St and a rotor Ro. The rotary electric machine MG has a function as a motor (electric motor) that receives supply of electric power to generate driving force, and a function as a generator (electric power generator) that receives supply of driving force to generate electric power. Therefore, the rotary electric machine MG is electrically connected to a power storage device (battery, capacitor, and the like). The rotary electric machine MG receives electric power supplied from the power storage device to perform power running, or supplies electric power generated with torque of the internal combustion engine EG or inertial force of the vehicle to the power storage device to cause the power storage device to store the electric power. 
     The internal combustion engine EG functions as a driving force source for the wheels W, similarly to the rotary electric machine MG. The internal combustion engine EG is a motor (gasoline engine, diesel engine, and the like) that is driven by combustion of fuel to take out driving force. 
     As shown in  FIG.  1   , the vehicle drive device  100  includes an input member  1 , output members  2 , a transmission  3 , and a case  4  in addition to the rotary electric machine MG. In the present embodiment, the vehicle drive device  100  further includes a fluid coupling  5 , a disconnecting engagement device  6 , a counter gear mechanism CG, and a differential gear mechanism DF. 
     The input member  1  is drivingly connected to the internal combustion engine EG. In the present embodiment, the input member  1  is drivingly connected to an output shaft of the internal combustion engine EG via a damper device DP (see  FIG.  2   ) that damps fluctuation in transmitted torque. 
     In the present application, “drivingly connected” refers to a state in which two rotation elements are connected so that a driving force can be transmitted, and includes a state in which the two rotation elements are connected so as to rotate integrally or a state in which the two rotation elements are connected so as to be able to transmit a driving force via one or two or more transmitting members. Such transmitting members include various members that transmit rotation at the same speed or at a changed speed, such as a shaft, a gear mechanism, a belt, and a chain. The transmitting members may include an engagement device that selectively transmits rotation and driving force, such as a friction engagement device and an intermeshing engagement device. 
     The disconnecting engagement device  6  is arranged in a power transmission path between the input member  1  and the rotary electric machine MG. The disconnecting engagement device  6  corresponds to a “first engagement device CL 1 ” that connects or disconnects power transmission between the input member  1  and the rotary electric machine MG. 
     The transmission  3  changes the speed of rotation transmitted from the rotary electric machine MG side and transmits the rotation to the output member  2  side. In the present embodiment, the transmission  3  includes a transmission input shaft  31  serving as an input element of the transmission  3 , and a transmission output gear  32  serving as an output element of the transmission  3 . As the transmission  3 , various known automatic transmissions are used, such as a stepped automatic transmission capable of switching a plurality of shift speeds, and a continuously variable automatic transmission capable of steplessly changing the speed ratio. 
     The fluid coupling  5  is arranged in a power transmission path between the rotary electric machine MG and the transmission  3 . The fluid coupling  5  includes a rotary housing  51 . In the present embodiment, the fluid coupling  5  is a torque converter including a pump impeller  52 , a turbine runner  53 , and a lockup clutch  54  in addition to the rotary housing  51 . 
     The rotary housing  51  is connected to the rotor Ro of the rotary electric machine MG so as to rotate integrally with the rotor Ro. The rotary housing  51  houses the pump impeller  52  and the turbine runner  53 . The pump impeller  52  and the turbine runner  53  are arranged so as to face each other in the axial direction L. In the present embodiment, the pump impeller  52  is arranged so as to face the turbine runner  53  on the first side L 1  in the axial direction. The pump impeller  52  and the turbine runner  53  are supported so as to rotate relative to each other. The pump impeller  52  is connected to the rotary housing  51  so as to rotate integrally with the rotary housing  51 . The turbine runner  53  is connected to the transmission input shaft  31  of the transmission  3  so as to rotate integrally with the transmission input shaft  31 . 
     The lockup clutch  54  is configured to selectively set the pump impeller  52  and the turbine runner  53  in a direct connection engaged state. That is, the lockup clutch  54  is configured to switch a state in which the rotary housing  51  that rotates integrally with the rotor Ro of the rotary electric machine MG is brought into direct connection engagement with the transmission input shaft  31  of the transmission  3  and a state in which power is transmitted via a fluid between the pump impeller  52  and the turbine runner  53 . Thus, the lockup clutch  54  corresponds to a “second engagement device CL 2 ” that connects or disconnects power transmission between the rotary electric machine MG and the transmission  3 . 
     The counter gear mechanism CG includes a counter input gear G 1  serving as an input element of the counter gear mechanism CG, and a counter output gear G 2  serving as an output element of the counter gear mechanism CG. The counter input gear G 1  meshes with the transmission output gear  32  of the transmission  3 . The counter output gear G 2  is connected to the counter input gear G 1  so as to rotate integrally with the counter input gear G 1 . In the present embodiment, the counter input gear G 1  and the counter output gear G 2  are connected so as to rotate integrally via a counter shaft CS extending along the axial direction L. 
     The differential gear mechanism DF includes a differential input gear G 3  that meshes with the counter output gear G 2  of the counter gear mechanism CG. The differential gear mechanism DF distributes the rotation of the differential input gear G 3  serving as an input element of the differential gear mechanism DF to the pair of output members  2 . 
     The output members  2  are drivingly connected to the wheels W. In the present embodiment, each of the pair of output members  2  is drivingly connected to the wheel W via a drive shaft DS. 
     The case  4  houses the rotary electric machine MG and the transmission  3 . In the present embodiment, the case  4  also houses the fluid coupling  5 , the disconnecting engagement device  6 , the counter gear mechanism CG, and the differential gear mechanism DF. 
     As shown in  FIG.  2   , the stator St of the rotary electric machine MG includes a stator core Stc fixed to a non-rotary member (in this case, the case  4 ). The rotor Ro of the rotary electric machine MG includes a rotor core Roc that rotates relative to the stator St. 
     In the present embodiment, the rotary electric machine MG is an inner rotor-type rotary electric machine. Therefore, the rotor core Roc is arranged on the inner side R 1  in the radial direction with respect to the stator core Stc. 
     In the present embodiment, the rotary electric machine MG is a revolving field-type rotary electric machine. Therefore, a stator coil is wound around the stator core Stc such that coil end portions Ce are formed so as to protrude from the stator core Stc to both sides in the axial direction L (first side L 1  in the axial direction and second side L 2  in the axial direction). The rotor core Roc includes permanent magnets (not shown). 
     As shown in  FIG.  2   , the vehicle drive device  100  includes a first bearing B 1  that supports a second rotary member RT 2  on a first rotary member RT 1  so that the second rotary member RT 2  rotates relative to the first rotary member RT 1 , and a second bearing B 2  that supports the first rotary member RT 1  on the case  4  so that the first rotary member RT 1  rotates relative to the case  4 . 
     The first rotary member RT 1  is the input member  1  or a member that rotates integrally with the input member  1 . In the present embodiment, the first rotary member RT 1  is the input member  1 . 
     The second rotary member RT 2  is the rotor Ro or a member that rotates integrally with the rotor Ro. In the present embodiment, the second rotary member RT 2  is the rotary housing  51  of the fluid coupling  5  or a member that rotates integrally with the rotary housing  51 . In this example, the second rotary member RT 2  is the rotary housing  51 . 
     As shown in  FIG.  3   , the input member  1  has a support outer peripheral surface  11   a  that faces the outer side R 2  in the radial direction, and a first radial support surface  13   a  that faces one side in the radial direction R. The rotary housing  51  has a support inner peripheral surface  51   a  that faces the inner side R 1  in the radial direction. In the present embodiment, the rotary housing  51  further has a rotor support surface  51   b  that faces the outer side R 2  in the radial direction. The rotor support surface  51   b  is formed so as to support the rotor Ro of the rotary electric machine MG from the inner side R 1  in the radial direction. That is, the rotor support surface  51   b  is formed in contact with the inner peripheral surface of the rotor Ro. 
     The case  4  includes a first support  41 . The first support  41  is a “support” that supports the second bearing B 2 . The first support  41  has a second radial support surface  41   a  that faces the first radial support surface  13   a  in the radial direction R. 
     The first bearing B 1  is arranged between the support outer peripheral surface  11   a  and the support inner peripheral surface  51   a  in the radial direction R. In the present embodiment, the first bearing B 1  is arranged such that the inner peripheral surface of the first bearing B 1  is in contact with the support outer peripheral surface  11   a  and the outer peripheral surface of the first bearing B 1  is in contact with the support inner peripheral surface  51   a . In the present embodiment, the first bearing B 1  is a radial bearing that supports the rotary housing  51  on the input member  1  in the radial direction R. In this example, the first bearing B 1  is a radial ball bearing. 
     The second bearing B 2  is arranged between the first radial support surface  13   a  and the second radial support surface  41   a  in the radial direction R. In the present embodiment, the second bearing B 2  is arranged such that the outer peripheral surface of the second bearing B 2  is in contact with the first radial support surface  13   a  and the inner peripheral surface of the second bearing B 2  is in contact with the second radial support surface  41   a . In the present embodiment, the second bearing B 2  is a radial bearing that supports the input member  1  on the case  4  in the radial direction R. In this example, the second bearing B 2  is a radial ball bearing. 
     The first bearing B 1  is arranged on the inner side R 1  in the radial direction with respect to the rotor Ro of the rotary electric machine MG at a position where the first bearing B 1  overlaps the rotor Ro in a radial view along the radial direction R. In the present embodiment, both the first bearing B 1  and the second bearing B 2  are arranged on the inner side R 1  in the radial direction with respect to the rotor Ro of the rotary electric machine MG at positions where the first bearing B 1  and the second bearing B 2  overlap the rotor Ro in the radial view. 
     In the present embodiment, the first bearing B 1  and the second bearing B 2  are arranged so as to overlap each other in the radial view along the radial direction R. It is preferable that more than a half of the area of the first bearing B 1  in the axial direction L overlap the second bearing B 2  in the radial view and more than a half of the area of the second bearing B 2  in the axial direction L overlap the first bearing B 1  in the radial view. In this example, three-fourths or more of the areas of the first bearing B 1  and the second bearing B 2  in the axial direction L overlap each other in the radial view. In the illustrated example, the dimension of the first bearing B 1  in the axial direction L is substantially equal to the dimension of the second bearing B 2  in the axial direction L. In the present embodiment, the first bearing B 1  is arranged on the outer side R 2  in the radial direction with respect to the second bearing B 2  at a position where the first bearing B 1  overlaps the second bearing B 2  in the radial view along the radial direction R. Regarding the arrangement of two elements, the phrase “overlap when viewed in a specific direction” means that, when a virtual straight line parallel to the line-of-sight direction is moved in directions orthogonal to the virtual straight line, an area where the virtual straight line intersects both the two elements is present at least in part. 
     According to this configuration, the dimension of the vehicle drive device  100  in the axial direction L can be reduced compared to a configuration in which the first bearing B 1  and the second bearing B 2  are arranged side by side in the axial direction L. 
     In the present embodiment, both the first bearing B 1  and the second bearing B 2  are arranged on the inner side R 1  in the radial direction with respect to the rotary electric machine MG at the positions where the first bearing B 1  and the second bearing B 2  overlap the rotary electric machine MG in the radial view along the radial direction R. In this example, the range of overlap with the rotary electric machine MG in the radial view is a range in the axial direction L from the end on the first side L 1  in the axial direction to the end on the second side L 2  in the axial direction in the stator St including the coil end portions Ce (see  FIG.  2   ). 
     According to this configuration, the dimension of the vehicle drive device  100  in the axial direction L can be reduced compared to a configuration in which at least one of the first bearing B 1  and the second bearing B 2  is arranged on one side in the axial direction L with respect to the rotary electric machine MG. 
     Further, in this example, both the first bearing B 1  and the second bearing B 2  are arranged at the positions where the first bearing B 1  and the second bearing B 2  overlap the rotor Ro in the radial view along the radial direction R. In this example, the range of overlap with the rotor Ro in the radial view is a range in the axial direction L from the end on the first side L 1  in the axial direction to the end on the second side L 2  in the axial direction in the rotor Ro (in this case, the rotor core Roc). 
     According to this configuration, the dimension of the vehicle drive device  100  in the axial direction L can be reduced compared to a configuration in which at least one of the first bearing B 1  and the second bearing B 2  is arranged on one side in the axial direction L with respect to the rotor Ro of the rotary electric machine MG. 
     In the present embodiment, the first radial support surface  13   a  is formed so as to face the inner side R 1  in the radial direction. 
     The second radial support surface  41   a  is formed so as to face the outer side R 2  in the radial direction. 
     According to this configuration, a space for arranging a member between the first rotary member RT 1  and the first support  41  in the radial direction R can easily be secured on the inner side R 1  in the radial direction with respect to the second radial support surface  41   a  of the first support  41  in the case  4 . That is, the configuration is such that the member to be arranged between the first rotary member RT 1  and the first support  41  in the radial direction R can easily be arranged on one side in the radial direction R with respect to the first bearing B 1  and the second bearing B 2 . As a result, the dimension of the vehicle drive device  100  in the axial direction L can easily be reduced even in a case where a predetermined member is arranged between the first rotary member RT 1  and the first support  41  in the radial direction R. 
     In the present embodiment, as shown in  FIG.  2   , the vehicle drive device  100  includes a third bearing B 3  and a fourth bearing B 4  that support the rotary housing  51  so that the rotary housing  51  is rotatable relative to the case  4 . 
     The third bearing B 3  is a radial bearing that supports the rotary housing  51  on the case  4  in the radial direction R. In the present embodiment, the third bearing B 3  supports an axially extending portion  517  of the rotary housing  51  on a second support  42  of the case  4  in the radial direction R. In this example, the third bearing B 3  is a radial roller bearing. 
     The axially extending portion  517  has a tubular shape having an axis along the axial direction L. The axially extending portion  517  is arranged so as to cover the transmission input shaft  31  on the outer side R 2  in the radial direction. The third bearing B 3  is movable in the axial direction L relative to at least one of the axially extending portion  517  and the second support  42 . As a result, the axially extending portion  517  is allowed to move in the axial direction L even if the dimension of the rotary housing  51  in the axial direction L varies due to, for example, expansion (so-called ballooning) of the rotary housing  51  caused by a hydraulic pressure inside the rotary housing  51 . 
     The fourth bearing B 4  is a thrust bearing that supports the rotary housing  51  on the case  4  in the axial direction L. In the present embodiment, the fourth bearing B 4  supports a radially extending portion  518  of the rotary housing  51  on the second support  42  of the case  4  in the axial direction L. In this example, the fourth bearing B 4  is a thrust roller bearing. 
     The radially extending portion  518  extends along the radial direction R so as to connect the axially extending portion  517  and a pump housing portion  519  that surrounds an outer side of the pump impeller  52  in the rotary housing  51 . In the present embodiment, the radially extending portion  518  is formed so as to connect the end of the pump housing portion  519  on the inner side R 1  in the radial direction and the end of the axially extending portion  517  on the second side L 2  in the axial direction. 
     In the present embodiment, the first bearing B 1  and the second bearing B 2  are arranged on the second side L 2  in the axial direction with respect to the pump impeller  52  and the turbine runner  53  of the fluid coupling  5 . The third bearing B 3  and the fourth bearing B 4  are arranged on the first side L 1  in the axial direction with respect to the pump impeller  52  and the turbine runner  53  of the fluid coupling  5 . As described above, in the present embodiment, each of the first bearing B 1 , the second bearing B 2 , and the third bearing B 3  is the radial bearing. Therefore, in the present embodiment, the rotary housing  51  is supported on the case  4  in the radial direction R via the two bearings B 1  and B 2  on the second side L 2  in the axial direction with respect to the pump impeller  52  and the turbine runner  53 , and is supported on the case  4  in the radial direction R via the one bearing B 3  on the first side L 1  in the axial direction with respect to the pump impeller  52  and the turbine runner  53 . Thus, in the present embodiment, the rotary housing  51  can be supported on the case  4  in the radial direction R with high support accuracy. 
     In the present embodiment, an elastic member  10  having elasticity in the axial direction L is provided between the fourth bearing B 4  and the radially extending portion  518  in the axial direction L. As the elastic member  10 , various elastic members can be used, such as a compression coil spring, a disc spring, and a washer made of rubber or synthetic resin. When the elastic member  10  is elastically deformed in the axial direction L, the radially extending portion  518  is allowed to move in the axial direction L even if the dimension of the rotary housing  51  in the axial direction L varies due to, for example, expansion (so-called ballooning) of the rotary housing  51  caused by the hydraulic pressure inside the rotary housing  51 . That is, the radially extending portion  518  is allowed to move in the axial direction L while being supported in the axial direction L by the fourth bearing B 4  and the elastic member  10 . Instead of arranging the elastic member  10  between the fourth bearing B 4  and the radially extending portion  518  in the axial direction L, the elastic member  10  may be arranged between the fourth bearing B 4  and the second support  42  of the case  4  in the axial direction L. 
     As shown in  FIG.  3   , in the present embodiment, the vehicle drive device  100  further includes a seal member S that seals the space between the input member  1  and the first support  41  in an oil-tight manner. 
     In the present embodiment, the input member  1  has a sealing outer peripheral surface  12   a  that faces the outer side R 2  in the radial direction. In the present embodiment, the first support  41  has a sealing inner peripheral surface  41   b  that faces the inner side R 1  in the radial direction. The seal member S is arranged between the sealing outer peripheral surface  12   a  and the sealing inner peripheral surface  41   b  in the radial direction R. In the present embodiment, the seal member S is arranged on the inner side R 1  in the radial direction with respect to the second bearing B 2 . 
     Thus, in the present embodiment, the vehicle drive device  100  further includes the seal member S that seals the space between the first rotary member RT 1  (in this case, the input member  1 ) and the first support  41  in an oil-tight manner. 
     The first rotary member RT 1  has the sealing outer peripheral surface  12   a  that faces the outer side R 2  in the radial direction. 
     The first support  41  has the sealing inner peripheral surface  41   b  that faces the inner side R 1  in the radial direction. The seal member S is arranged between the sealing outer peripheral surface  12   a  and the sealing inner peripheral surface  41   b  in the radial direction R. 
     With this configuration, it is possible to appropriately avoid outflow of oil from the space between the first rotary member RTI and the first support  41 . With this configuration in the present embodiment, the seal member S can be arranged on one side in the radial direction R (in this case, the inner side R 1  in the radial direction) with respect to the first bearing B 1  and the second bearing B 2 . As a result, the dimension of the vehicle drive device  100  in the axial direction L can easily be reduced even in the configuration in which the seal member S is arranged between the first rotary member RT 1  and the first support  41  in the radial direction R. 
     In the present embodiment, the input member  1  includes an outer tubular portion  11 , an inner tubular portion  12 , and a connecting portion  13 . The outer tubular portion  11  has a tubular shape having an axis along the axial direction L. The inner tubular portion  12  has a tubular shape having an axis along the axial direction L. The inner tubular portion  12  is arranged on the inner side R 1  in the radial direction with respect to the outer tubular portion  11 . The connecting portion  13  is formed so as to extend along the radial direction R. The connecting portion  13  is formed so as to connect the outer tubular portion  11  and the inner tubular portion  12 . In the illustrated example, the outer tubular portion  11  is formed so as to extend to the first side L 1  in the axial direction from the end of the connecting portion  13  on the outer side R 2  in the radial direction. The inner tubular portion  12  is formed so as to extend to the second side L 2  in the axial direction from the end of the connecting portion  13  on the inner side R 1  in the radial direction. 
     In the present embodiment, the support outer peripheral surface  11   a  is formed on the outer peripheral surface of the outer tubular portion  11 . The sealing outer peripheral surface  12   a  is formed on the outer peripheral surface of the inner tubular portion  12 . The connecting portion  13  has a stepped surface that faces the inner side R 1  in the radial direction, and this stepped surface is the first radial support surface  13   a . Specifically, the connecting portion  13  includes a first step portion  131  that forms the first radial support surface  13   a  serving as the stepped surface that faces the inner side R 1  in the radial direction. In the illustrated example, the first step portion  131  is formed so as to bend to the second side L 2  in the axial direction from a portion of the connecting portion  13  on the inner side R 1  in the radial direction with respect to the first step portion  131  and bend to the first side L 1  in the axial direction from a portion of the connecting portion  13  on the outer side R 2  in the radial direction with respect to the first step portion  131 . The inner peripheral surface of the portion extending in the axial direction L in the first step portion  131  is the first radial support surface  13   a  serving as the stepped surface. 
     As described above, in the present embodiment, the first rotary member RT 1  (in this case, the input member  1 ) includes the outer tubular portion  11  having the tubular shape having the axis along the axial direction L, the inner tubular portion  12  having the tubular shape having the axis along the axial direction L and arranged on the inner side R 1  in the radial direction with respect to the outer tubular portion  11 , and the connecting portion  13  that extends along the radial direction R and connects the outer tubular portion  11  and the inner tubular portion  12 . 
     The support outer peripheral surface  11   a  is formed on the outer peripheral surface of the outer tubular portion  11 . 
     The sealing outer peripheral surface  12   a  is formed on the outer peripheral surface of the inner tubular portion  12 . 
     The connecting portion  13  has the stepped surface that faces the inner side R 1  in the radial direction. 
     The stepped surface is the first radial support surface  13   a.    
     According to this configuration, the support outer peripheral surface  11   a , the first radial support surface  13   a , and the sealing outer peripheral surface  12   a  can appropriately be formed on the first rotary member RT 1 . 
     In the present embodiment, as shown in  FIG.  2   , the case  4  includes the second support  42  and a tubular body  43  in addition to the first support  41  described above. The tubular body  43  has a tubular shape having an axis along the axial direction L. Each of the first support  41  and the second support  42  is formed so as to extend along the radial direction R. The first support  41  and the second support  42  are arranged apart from each other in the axial direction L. In the present embodiment, the second support  42  is arranged on the first side L 1  in the axial direction with respect to the first support  41 . The first support  41  and the second support  42  are connected to the tubular body  43  so as to extend to the inner side R 1  in the radial direction from the tubular body  43 . In the present embodiment, the rotary electric machine MG, the fluid coupling  5 , and the disconnecting engagement device  6  are arranged in a space surrounded by the first support  41 , the second support  42 , and the tubular body  43 . 
     As shown in  FIG.  3   , in the present embodiment, the first support  41  includes a tubular support portion  411  having a tubular shape having an axis along the axial direction L, and a radially extending portion  412  extending to the outer side R 2  in the radial direction from the tubular support portion  411 . In the present embodiment, the tubular support portion  411  is formed so as to cover the inner tubular portion  12  of the input member  1  on the outer side R 2  in the radial direction. The radially extending portion  412  extends along the radial direction R so as to connect the tubular support portion  411  and the tubular body  43 . In the present embodiment, the radially extending portion  412  and the connecting portion  13  of the input member  1  are arranged side by side in the axial direction L. In this case, the radially extending portion  412  and the connecting portion  13  are arranged so as to face each other in the axial direction L in a state in which no other member is interposed therebetween in the axial direction L. In the illustrated example, the radially extending portion  412  is arranged to adjoin the connecting portion  13  on the second side L 2  in the axial direction. 
     The radially extending portion  412  and the connecting portion  13  are arranged parallel to each other. 
     In the present embodiment, the second radial support surface  41   a  is formed on the outer peripheral surface of the tubular support portion  411 . The sealing inner peripheral surface  41   b  is formed on the inner peripheral surface of the tubular support portion  411 . 
     As described above, in the present embodiment, the first support  41  includes the tubular support portion  411  having the tubular shape having the axis along the axial direction L, and the radially extending portion  412  extending to the outer side R 2  in the radial direction from the tubular support portion  411 . 
     The second radial support surface  41   a  is formed on the outer peripheral surface of the tubular support portion  411 . 
     The sealing inner peripheral surface  41   b  is formed on the inner peripheral surface of the tubular support portion  411 . The radially extending portion  412  and the connecting portion  13  are arranged side by side in the axial direction L. 
     According to this configuration, the second radial support surface  41   a  and the sealing inner peripheral surface  41   b  can appropriately be formed on the first support  41  of the case  4 . Since the radially extending portion  412  of the first support  41  and the connecting portion  13  of the first rotary member RT 1  (in this case, the input member  1 ) are arranged side by side in the axial direction L, the arrangement areas of the radially extending portion  412  and the connecting portion  13  in the axial direction L can be reduced easily and, by extension, the dimension of the vehicle drive device  100  in the axial direction L can be reduced easily. 
     As described above, in the present embodiment, the vehicle drive device  100  further includes the fluid coupling  5  arranged in the power transmission path between the rotary electric machine MG and the transmission  3 . 
     The fluid coupling  5  includes the rotary housing  51  that rotates integrally with the rotor Ro, and the lockup clutch  54  that is the second engagement device CL 2 . 
     The second rotary member RT 2  is the rotary housing  51  or a member that rotates integrally with the rotary housing  51 . 
     According to this configuration, the support inner peripheral surface  51   a  can appropriately be formed by using the rotary housing  51  of the fluid coupling  5  or the member that rotates integrally with the rotary housing  51 . 
     In the present embodiment, the rotary housing  51  includes a tubular portion  511  having a tubular shape having an axis along the axial direction L. In the illustrated example, the tubular portion  511  is formed so as to protrude to the second side L 2  in the axial direction from the end of a turbine housing portion  520  on the inner side R 1  in the radial direction. The turbine housing portion  520  is a portion surrounding an outer side of the turbine runner  53  in the rotary housing  51 . In the present embodiment, the support inner peripheral surface  51   a  is formed on the inner peripheral surface of the tubular portion  511 . Further, the rotor support surface  51   b  is formed on the outer peripheral surface of the tubular portion  511 . 
     As described above, in the present embodiment, the second rotary member RT 2  has the rotor support surface  51   b  that is formed so as to face the outer side R 2  in the radial direction and supports the rotor Ro from the inner side R 1  in the radial direction. 
     The rotary housing  51  includes the tubular portion  511  having the tubular shape having the axis along the axial direction L. 
     The support inner peripheral surface  51   a  is formed on the inner peripheral surface of the tubular portion  511 . 
     The rotor support surface  51   b  is formed on the outer peripheral surface of the tubular portion  511 . 
     According to this configuration, the rotor Ro of the rotary electric machine MG and the first bearing B 1  can be arranged side by side in the radial direction R with the tubular portion  511  of the rotary housing  51  interposed therebetween. Therefore, the dimension of the vehicle drive device  100  in the axial direction L can be reduced easily. 
     In the present embodiment, the seal member S is arranged so as to overlap, in the radial view along the radial direction R, at least one of the first bearing B 1 , the second bearing B 2 , a first support portion SP 1 , a second support portion SP 2 , a third support portion SP 3 , and a fourth support portion SP 4 . In the illustrated example, the seal member S is arranged so as to overlap the first bearing B 1 , the first support portion SP 1 , the second support portion SP 2 , and the fourth support portion SP 4  in the radial view. 
     The first support portion SP 1  is a portion that forms a surface of the first rotary member RT 1  in contact with the first bearing B 1 . As described above, in the present embodiment, the outer tubular portion  11  of the input member  1  that is the first rotary member RT 1  has the support outer peripheral surface  11   a  in contact with the first bearing B 1  from the inner side R 1  in the radial direction. In the present embodiment, the outer tubular portion  11  has, in addition to the support outer peripheral surface  11   a , a first side surface  11   b  in contact with the first bearing B 1  from the first side L 1  in the axial direction. Therefore, in the present embodiment, the first support portion SP 1  is a portion of the outer tubular portion  11  that forms the support outer peripheral surface  11   a  and the first side surface  11   b . In this case, the portion that forms the support outer peripheral surface  11   a  and the first side surface  11 is not only an area that extends along the support outer peripheral surface Ila and the first side surface  11   b  and is in contact with the first bearing B 1 , but also a portion including the entire area in a thickness direction from the support outer peripheral surface  11   a  and the first side surface  11   b  to a surface that faces the opposite side to those for the respective surfaces. 
     The second support portion SP 2  is a portion that forms a surface of the second rotary member RT 2  in contact with the first bearing B 1 . As described above, in the present embodiment, the tubular portion  511  of the rotary housing  51  that is the second rotary member RT 2  has the support inner peripheral surface  51   a  in contact with the first bearing B 1  from the outer side R 2  in the radial direction. Therefore, in the present embodiment, the second support portion SP 2  is a portion of the tubular portion  511  that forms the support inner peripheral surface  51   a . In this case, the portion that forms the support inner peripheral surface  51   a  is not only an area that extends along the support inner peripheral surface  51   a  and is in contact with the first bearing B 1 , but also a portion including the entire area in the thickness direction from the support inner peripheral surface  51   a  to a surface that faces the opposite side to that for this surface. 
     The third support portion SP 3  is a portion that forms a surface of the first rotary member RT 1  in contact with the second bearing B 2 . As described above, in the present embodiment, the first step portion  131  formed on the connecting portion  13  of the input member  1  that is the first rotary member RT 1  has the first radial support surface  13   a  in contact with the second bearing B 2  from the outer side R 2  in the radial direction. In the present embodiment, the first step portion  131  has, in addition to the first radial support surface  13   a , a second side surface  13   b  in contact with the second bearing B 2  from the first side L 1  in the axial direction. Therefore, in the present embodiment, the third support portion SP 3  is a portion of the first step portion  131  that forms the first radial support surface  13   a  and the second side surface  13   b . In this case, the portion that forms the first radial support surface  13   a  and the second side surface  13   b  is not only an area that extends along the first radial support surface  13   a  and the second side surface  13   b  and is in contact with the second bearing B 2 , but also a portion including the entire area in the thickness direction from the first radial support surface  13   a  and the second side surface  13   b  to a surface that faces the opposite side to those for the respective surfaces. 
     The fourth support portion SP 4  is a portion that forms a surface of the first support  41  in contact with the second bearing B 2 . As described above, in the present embodiment, the tubular support portion  411  of the first support  41  has the second radial support surface  41   a  in contact with the second bearing B 2  from the inner side R 1  in the radial direction. In the present embodiment, the tubular support portion  411  has, in addition to the second radial support surface  41   a , a support side surface  41   c  in contact with the second bearing B 2  from the second side L 2  in the axial direction. Therefore, in the present embodiment, the fourth support portion SP 4  is a portion of the tubular support portion  411  that forms the second radial support surface  41   a  and the support side surface  41   c . In this case, the portion that forms the second radial support surface  41   a  and the support side surface  41   c  is not only an area that extends along the second radial support surface  41   a  and the support side surface  41   c  and is in contact with the second bearing B 2 , but also a portion including the entire area in the thickness direction from the second radial support surface  41   a  and the support side surface  41   c  to a surface that faces the opposite side to those for the respective surfaces. 
     As described above, in the present embodiment, the portion of the first rotary member RT 1  (in this case, the input member  1 ) that forms the surface in contact with the first bearing B 1  is defined as the first support portion SP 1 , the portion of the second rotary member RT 2  (in this case, the rotary housing  51 ) that forms the surface in contact with the first bearing B 1  is defined as the second support portion SP 2 , the portion of the first rotary member RT 1  that forms the surface in contact with the second bearing B 2  is defined as the third support portion SP 3 , and the portion of the first support  41  that forms the surface in contact with the second bearing B 2  is defined as the fourth support portion SP 4 . 
     The seal member S is arranged so as to overlap, in the radial view along the radial direction R, at least one of the first bearing B 1 , the second bearing B 2 , the first support portion SP 1 , the second support portion SP 2 , the third support portion SP 3 , and the fourth support portion SP 4 . 
     According to this configuration, the dimension of the vehicle drive device  100  in the axial direction L can be reduced compared to a configuration in which the seal member S is arranged on one side in the axial direction L with respect to the first bearing B 1 , the second bearing B 2 , the first support portion SP 1 , the second support portion SP 2 , the third support portion SP 3 , and the fourth support portion SP 4 . 
     As shown in  FIG.  3   , in the present embodiment, the disconnecting engagement device  6  serving as the first engagement device CL 1  includes a first friction member  61 , a first piston portion  62  that presses the first friction member  61  in the axial direction L, and a first hydraulic oil chamber  63  to which oil for operating the first piston portion  62  is supplied. 
     The first friction member  61  includes a first inner friction material  611  and a first outer friction material  612 . The first inner friction material  611  and the first outer friction material  612  both have an annular plate shape, and are arranged such that their rotation axes coincide with each other (coaxially). A plurality of the first inner friction materials  611  and a plurality of the first outer friction materials  612  are provided, and these are arranged alternately along the axial direction L. Either the first inner friction materials  611  or the first outer friction materials  612  may be friction plates and the remaining may be separate plates. 
     The first outer friction materials  612  are supported from the outer side R 2  in the radial direction by a first friction material support portion  14  of the input member  1 . The first friction material support portion  14  has a tubular shape having an axis along the axial direction L. In the present embodiment, the first friction material support portion  14  is connected to the outer tubular portion  11  so as to rotate integrally with the outer tubular portion  11 . In the illustrated example, the first friction material support portion  14  is formed so as to extend to the first side L 1  in the axial direction from the outer tubular portion  11 . In the illustrated example, the first friction material support portion  14  is formed integrally with the outer tubular portion  11 . In the present embodiment, the first friction material support portion  14  is arranged on the inner side R 1  in the radial direction with respect to the tubular portion  511  of the rotary housing  51 . 
     In this example, a plurality of spline grooves extending in the axial direction 
     L is formed in the outer peripheral portions of the first outer friction materials  612  so as to be distributed in the circumferential direction. Similar spline grooves are also formed in the inner peripheral portion of the first friction material support portion  14  so as to be distributed in the circumferential direction. When the spline grooves are engaged with each other, the first outer friction materials  612  are supported by the first friction material support portion  14  from the outer side R 2  in the radial direction. In this way, the first outer friction materials  612  are supported so as to be slidable in the axial direction L with their rotation relative to the first friction material support portion  14  being restricted. 
     The first inner friction materials  611  are supported from the inner side R 1  in the radial direction by a second friction material support portion  512  of the rotary housing  51 . The second friction material support portion  512  has a tubular shape having an axis along the axial direction L. In the present embodiment, the second friction material support portion  512  is formed by a part of the rotary housing  51  and connected to the tubular portion  511  so as to rotate integrally with the tubular portion  511 . In the illustrated example, the second friction material support portion  512  is formed so as to extend to the inner side R 1  in the radial direction from the end of the tubular portion  511  on the first side L 1  in the axial direction and further extend to the second side L 2  in the axial direction. 
     In this example, a plurality of spline grooves extending in the axial direction L is formed in the inner peripheral portions of the first inner friction materials  611  so as to be distributed in the circumferential direction. Similar spline grooves are also formed in the outer peripheral portion of the second friction material support portion  512  so as to be distributed in the circumferential direction. When the spline grooves are engaged with each other, the first inner friction materials  611  are supported by the second friction material support portion  512  from the inner side R 1  in the radial direction. In this way, the first inner friction materials  611  are supported so as to be slidable in the axial direction L with their rotation relative to the second friction material support portion  512  being restricted. 
     The first piston portion  62  is configured to press the first friction member  61  with a pressure corresponding to a hydraulic pressure supplied to the first hydraulic oil chamber  63 . In the present embodiment, the first piston portion  62  includes a first sliding portion  621  and a first pressing portion  622 . 
     In the present embodiment, the connecting portion  13  of the input member  1  includes a second step portion  132  that forms a stepped surface  132   a  that faces the outer side R 2  in the radial direction. In the illustrated example, the second step portion  132  is formed so as to protrude to the first side L 1  in the axial direction. The first sliding portion  621  is configured to slide in the axial direction L between the stepped surface  132   a  of the second step portion  132  and an inner peripheral surface  11   c  of the outer tubular portion  11  of the input member  1 . That is, in the present embodiment, the second step portion  132  and the outer tubular portion  11  form a cylinder portion on which the first sliding portion  621  slides. The first sliding portion  621  has a bottomed double cylinder shape including an annular plate-shaped portion extending along the radial direction R and the circumferential direction, and two tubular portions extending in the axial direction L from the end of the annular plate-shaped portion on the inner side R 1  in the radial direction and the end of the annular plate-shaped portion on the outer side R 2  in the radial direction. 
     The first pressing portion  622  presses the first friction member  61  in the axial direction L. In the present embodiment, the first pressing portion  622  is arranged to adjoin the first friction member  61  on the second side L 2  in the axial direction. In the illustrated example, the first pressing portion  622  is formed so as to extend from the first sliding portion  621  to the first side L 1  in the axial direction and further extend to the outer side R 2  in the radial direction. 
     The first hydraulic oil chamber  63  is arranged to adjoin the first piston portion  62  in the axial direction L. In the present embodiment, the first hydraulic oil chamber  63  is defined by the first sliding portion  621 , the outer tubular portion  11 , the second step portion  132 , and a part of the connecting portion  13  between the outer tubular portion  11  and the second step portion  132 . 
     In the present embodiment, at least one of the first piston portion  62  and the first hydraulic oil chamber  63  is arranged between the first bearing B 1  and the second bearing B 2  in the radial direction R at a position where the at least one of the first piston portion  62  and the first hydraulic oil chamber  63  overlaps at least one of the first bearing B 1  and the second bearing B 2  in the radial view along the radial direction R. In the illustrated example, both the first piston portion  62  and the first hydraulic oil chamber  63  are arranged so as to overlap both the first bearing B 1  and the second bearing B 2  in the radial view. 
     Thus, in the present embodiment, the first engagement device CL 1  (in this case, the disconnecting engagement device  6 ) that connects or disconnects the power transmission between the input member  1  and the rotary electric machine MG is further provided. 
     The first engagement device CL 1  includes the first friction member  61 , the first piston portion  62  that presses the first friction member  61  in the axial direction L, and the first hydraulic oil chamber  63  to which the oil for operating the first piston portion  62  is supplied. 
     At least one of the first piston portion  62  and the first hydraulic oil chamber  63  is arranged between the first bearing B 1  and the second bearing B 2  in the radial direction R at the position where the at least one of the first piston portion  62  and the first hydraulic oil chamber  63  overlaps at least one of the first bearing B 1  and the second bearing B 2  in the radial view along the radial direction R. 
     According to this configuration, the dimension of the vehicle drive device  100  in the axial direction L can be reduced compared to a configuration in which both the first piston portion  62  and the first hydraulic oil chamber  63  are arranged on one side in the axial direction L with respect to the first bearing B 1  and the second bearing B 2 . 
     In the present embodiment, the first piston portion  62  is arranged between the first bearing B 1  and the second bearing B 2  in the radial direction R at a position where the first piston portion  62  overlaps at least one of the first bearing B 1  and the second bearing B 2  in the radial view along the radial direction R. In the illustrated example, the first piston portion  62  is arranged so as to overlap both the first bearing B 1  and the second bearing B 2  in the radial view. 
     According to this configuration, the dimension of the vehicle drive device  100  in the axial direction L can be reduced compared to a configuration in which the first piston portion  62  is arranged on one side in the axial direction L with respect to the first bearing B 1  and the second bearing B 2 . 
     In the present embodiment, a first elastic body  64  having an annular shape extending along the circumferential direction and having elasticity in the axial direction L is arranged between a pair of first outer friction materials  612  adjacent to each other in the axial direction L out of the plurality of first outer friction materials  612 . The first elastic body  64  separates the adjacent first outer friction materials  612  away from each other in the axial direction L by its elastic force when the hydraulic pressure supplied to the first hydraulic oil chamber  63  is lower than a predetermined value. As a result, a releasing operation of the disconnecting engagement device  6  is appropriately performed, thereby reducing a drag torque between the friction materials and avoiding a case where the disconnecting engagement device  6  is engaged unintendedly due to a centrifugal hydraulic pressure or the like. For example, a wave spring can be used as the first elastic body  64 . 
     As shown in  FIG.  3   , in the present embodiment, the lockup clutch  54  serving as the second engagement device CL 2  includes a second friction member  55 , a second piston portion  56  that presses the second friction member  55  in the axial direction L, and a second hydraulic oil chamber  57  to which oil for operating the second piston portion  56  is supplied. 
     The second friction member  55  includes a second inner friction material  551  and a second outer friction material  552 . The second inner friction material  551  and the second outer friction material  552  both have an annular plate shape, and are arranged such that their rotation axes coincide with each other (coaxially). A plurality of the second inner friction materials  551  and a plurality of the second outer friction materials  552  are provided, and these are arranged alternately along the axial direction L. Either the second inner friction materials  551  or the second outer friction materials  552  may be friction plates and the remaining may be separate plates. 
     The second outer friction materials  552  are supported from the outer side R 2  in the radial direction by the second friction material support portion  512 . In this example, a plurality of spline grooves extending in the axial direction L is formed in the outer peripheral portions of the second outer friction materials  552  so as to be distributed in the circumferential direction. Similar spline grooves are also formed in the inner peripheral portion of the second friction material support portion  512  so as to be distributed in the circumferential direction. When the spline grooves are engaged with each other, the second outer friction materials  552  are supported by the second friction material support portion  512  from the outer side R 2  in the radial direction. In this way, the second outer friction materials  552  are supported so as to be slidable in the axial direction L with their rotation relative to the second friction material support portion  512  being restricted. 
     The second inner friction materials  551  are supported by a support member  7 . The support member  7  is connected to the turbine runner  53  of the fluid coupling  5  and the transmission input shaft  31  of the transmission  3  so as to rotate integrally with the turbine runner  53  and the transmission input shaft  31 . In the present embodiment, the transmission input shaft  31  includes a connecting portion  311  extending to the outer side R 2  in the radial direction. The end of the turbine runner  53  on the inner side R 1  in the radial direction and the end of the support member  7  on the inner side R 1  in the radial direction overlap, in the axial direction L, the end of the connecting portion  311  on the outer side R 2  in the radial direction, and these ends are integrally connected. 
     The support member  7  includes a third friction material support portion  71 . The third friction material support portion  71  has a tubular shape having an axis along the axial direction L. The third friction material support portion  71  is formed so as to extend to the second side L 2  in the axial direction from a part of the support member  7  connected to the transmission input shaft  31 . 
     In this example, a plurality of spline grooves extending in the axial direction L is formed in the inner peripheral portions of the second inner friction materials  551  so as to be distributed in the circumferential direction. Similar spline grooves are also formed in the outer peripheral portion of the third friction material support portion  71  so as to be distributed in the circumferential direction. When the spline grooves are engaged with each other, the second inner friction materials  551  are supported by the third friction material support portion  71  from the inner side R 1  in the radial direction. In this way, the second inner friction materials  551  are supported so as to be slidable in the axial direction L with their rotation relative to the third friction material support portion  71  being restricted. 
     The second piston portion  56  is configured to press the second friction member  55  with a pressure corresponding to a hydraulic pressure supplied to the second hydraulic oil chamber  57 . In the present embodiment, the second piston portion  56  includes a second sliding portion  561  and a second pressing portion  562 . 
     The second sliding portion  561  is configured to slide inside a cylinder portion formed by a cylinder forming portion  513  of the rotary housing  51 . The second sliding portion  561  has an annular plate shape extending along the radial direction R and the circumferential direction. 
     The cylinder forming portion  513  includes an outer peripheral portion  514 , an inner peripheral portion  515 , and a connecting portion  516 . The outer peripheral portion  514  has a tubular shape having an axis along the axial direction L. The inner peripheral portion  515  has a tubular shape having an axis along the axial direction L. The inner peripheral portion  515  is arranged on the inner side R 1  in the radial direction with respect to the outer peripheral portion  514 . The connecting portion  516  is formed so as to extend along the radial direction R. The connecting portion  516  is formed so as to connect the outer peripheral portion  514  and the inner peripheral portion  515 . In the illustrated example, the outer peripheral portion  514  is formed so as to extend to the first side L 1  in the axial direction from the end of the connecting portion  516  on the outer side R 2  in the radial direction. The inner peripheral portion  515  is formed so as to extend to the first side L 1  in the axial direction from the end of the connecting portion  516  on the inner side R 1  in the radial direction. The outer peripheral portion  514 , the inner peripheral portion  515 , and the connecting portion  516  formed as described above form the cylinder portion on which the second sliding portion  561  slides. 
     The second pressing portion  562  presses the second friction member  55  in the axial direction L. In the present embodiment, the second pressing portion  562  is arranged to adjoin the second friction member  55  on the second side L 2  in the axial direction. In the illustrated example, the second pressing portion  562  is formed so as to protrude to the first side L 1  in the axial direction from a part of the second sliding portion  561  on the outer side R 2  in the radial direction. 
     The second hydraulic oil chamber  57  is arranged to adjoin the second piston portion  56  in the axial direction L. In the present embodiment, the second hydraulic oil chamber  57  is defined by the second sliding portion  561 , the outer peripheral portion  514 , the inner peripheral portion  515 , and the connecting portion  516 . 
     In the present embodiment, the second sliding portion  561  of the second piston portion  56  is urged to the first side L 1  in the axial direction by a plurality of urging members  58  distributed in the circumferential direction. The urging members  58  move the second piston portion  56  away from the second friction member  55  to the first side L 1  in the axial direction by its urging force when the hydraulic pressure supplied to the second hydraulic oil chamber  57  is lower than a predetermined value. As a result, a releasing operation of the lockup clutch  54  can appropriately be performed. Further, it is possible to avoid a case where the lockup clutch  54  is engaged unintendedly due to a centrifugal hydraulic pressure or the like. For example, a compression coil spring can be used as the urging member  58 . 
     In the present embodiment, a second elastic body  59  having an annular shape extending along the circumferential direction and having elasticity in the axial direction L is arranged between a pair of second outer friction materials  552  adjacent to each other in the axial direction L out of the plurality of second outer friction materials  552 . The second elastic body  59  separates the adjacent second outer friction materials  552  away from each other in the axial direction L by its elastic force when the hydraulic pressure supplied to the second hydraulic oil chamber  57  is lower than a predetermined value. As a result, a releasing operation of the lockup clutch  54  is appropriately performed, thereby reducing a drag torque between the friction materials and avoiding a case where the lockup clutch  54  is engaged unintendedly due to a centrifugal hydraulic pressure or the like. For example, a wave spring can be used as the second elastic body  59 . 
     In the present embodiment, the lockup clutch  54  is arranged on the inner side R 1  in the radial direction with respect to the disconnecting engagement device  6  at a position where the lockup clutch  54  overlaps the disconnecting engagement device  6  in the radial view along the radial direction R. In the illustrated example, the second friction member  55  of the lockup clutch  54  is arranged on the inner side R 1  in the radial direction with respect to the first friction member  61  of the disconnecting engagement device  6  at a position where the second friction member  55  overlaps the first friction member  61  in the radial view along the radial direction R. As described above, this structure is realized by the second friction material support portion  512  supporting the first inner friction materials  611  of the first friction member  61  from the inner side R 1  in the radial direction and supporting the second outer friction materials  552  of the second friction member  55  from the outer side R 2  in the radial direction. 
     In the present embodiment, the first piston portion  62  and the second hydraulic oil chamber  57  are arranged so as to overlap each other in the radial view along the radial direction R. In the present embodiment, both the disconnecting engagement device  6  and the lockup clutch  54  are arranged on the inner side R 1  in the radial direction with respect to the rotor Ro of the rotary electric machine MG at positions where the disconnecting engagement device  6  and the lockup clutch  54  overlap the rotor Ro in the radial view. 
     Thus, in the present embodiment, the second engagement device CL 2  (in this case, the lockup clutch  54 ) that connects or disconnects the power transmission between the rotary electric machine MG and the transmission  3  is further provided. 
     The second engagement device CL 2  includes the second friction member  55 , the second piston portion  56  that presses the second friction member  55  in the axial direction L, and the second hydraulic oil chamber  57  to which the oil for operating the second piston portion  56  is supplied. 
     The second engagement device CL 2  is arranged on the inner side R 1  in the radial direction with respect to the first engagement device CL 1  (in this case, the disconnecting engagement device  6 ) at a position where the second engagement device CL 2  overlaps the first engagement device CL 1  in the radial view along the radial direction R. 
     The first piston portion  62  and the second hydraulic oil chamber  57  are arranged so as to overlap each other in the radial view. 
     Both the first engagement device CL 1  and the second engagement device CL 2  are arranged on the inner side R 1  in the radial direction with respect to the rotor Ro at positions where the first engagement device CL 1  and the second engagement device CL 2  overlap the rotor Ro in the radial view. 
     According to this configuration, the dimension of the vehicle drive device  100  in the axial direction L can be reduced compared to a configuration in which the second engagement device CL 2  is arranged on one side in the axial direction L with respect to the first engagement device CL 1 . 
     In the present embodiment, both the first engagement device CL 1  (in this case, the disconnecting engagement device  6 ) and the second engagement device CL 2  (in this case, the lockup clutch  54 ) are arranged on the inner side R 1  in the radial direction with respect to the rotary electric machine MG at the positions where the first engagement device CL 1  and the second engagement device CL 2  overlap the rotary electric machine MG in the radial view along the radial direction R. 
     According to this configuration, the dimension of the vehicle drive device  100  in the axial direction L can be reduced compared to a configuration in which at least one of the first engagement device CL 1  and the second engagement device CL 2  is arranged on one side in the axial direction L with respect to the rotary electric machine MG. 
     In this example, the first engagement device CL 1  (in this case, the disconnecting engagement device  6 ) and the second engagement device CL 2  (in this case, the lockup clutch  54 ) are arranged at the positions where the first engagement device CL 1  and the second engagement device CL 2  overlap the rotor Ro in the radial view along the radial direction R. In the illustrated example, the entire first engagement device CL 1  and the entire second engagement device CL 2  are arranged so as to overlap the rotor Ro in the radial view. 
     According to this configuration, the dimension of the vehicle drive device  100  in the axial direction L can be reduced compared to a configuration in which at least one of the first engagement device CL 1  and the second engagement device CL 2  is arranged on one side in the axial direction L with respect to the rotor Ro. 
     2. Second Embodiment 
     Hereinafter, a vehicle drive device  100  according to a second embodiment will be described with reference to the drawings. The present embodiment differs from the first embodiment in that the fourth bearing B 4  and the elastic member  10  are not provided and a fixing member  20  and a guide member  30  are provided. In the present embodiment, the support structure for the rotor Ro is different from that in the first embodiment. The differences from the first embodiment will mainly be described below. Points that are not particularly described are the same as those in the first embodiment. 
     As shown in  FIG.  4   , in the present embodiment, the fixing member  20  is provided instead of providing the fourth bearing B 4  and the elastic member  10 . The fixing member  20  is a member that restricts movement of the second bearing B 2  in the axial direction L. In the present embodiment, the fixing member  20  restricts movement of the second bearing B 2  in the axial direction L relative to the tubular support portion  411  of the first support  41  in the case  4 . In the illustrated example, the fixing member  20  is a snap ring having an annular shape and fitted into grooves formed in the inner peripheral surface of the second bearing B 2  and the outer peripheral surface of the tubular support portion  411 . 
     Thus, in the present embodiment, the fixing member  20  restricts the movement of the second bearing B 2  in the axial direction L relative to the tubular support portion  411  of the first support  41 . Therefore, the second bearing B 2  hardly detaches from the tubular support portion  411  even if the first support  41  of the case  4  is deformed so as to be displaced in the axial direction L because the dimension of the rotary housing  51  in the axial direction L varies due to, for example, expansion (so-called ballooning) of the rotary housing  51  caused by the hydraulic pressure inside the rotary housing  51 . 
     In the present embodiment, the rotary housing  51  does not have the tubular portion  511 . A rotor support member  9  is connected to the rotary housing  51  so as to rotate integrally with the rotary housing  51 . The rotor support member  9  is a member that supports the rotor Ro from the inner side R 1  in the radial direction. In the present embodiment, the rotor support member  9  functions as the second rotary member RT 2 . As shown in  FIG.  5   , in the present embodiment, the rotor support member  9  includes an outer peripheral support portion  91 , an inner peripheral support portion  92 , and a fixing portion  93 . 
     The outer peripheral support portion  91  has a tubular shape having an axis along the axial direction L. In the present embodiment, the rotor support surface  51   b  is formed on the outer peripheral surface of the outer peripheral support portion  91 . The support inner peripheral surface  51   a  is formed on the inner peripheral surface of the outer peripheral support portion  91 . Therefore, in the present embodiment, a part of the outer peripheral support portion  91  function as the second support portion SP 2  that forms the surface of the second rotary member RT 2  (in this case, the rotor support member  9 ) in contact with the first bearing B 1 . 
     The inner peripheral support portion  92  has a tubular shape having an axis along the axial direction L. The inner peripheral support portion  92  is arranged on the inner side R 1  in the radial direction with respect to the outer peripheral support portion  91 . In the present embodiment, the second friction material support portion  512  does not support the first inner friction materials  611 , and the inner peripheral support portion  92  supports the first inner friction materials  611  from the inner side R 1  in the radial direction. In this example, a plurality of spline grooves engaged with the plurality of spline grooves formed in the inner peripheral portions of the first inner friction materials  611  is formed in the outer peripheral portion of the inner peripheral support portion  92  so as to extend in the axial direction L and to be distributed in the circumferential direction. When the spline grooves of the first inner friction materials  611  and the spline grooves of the inner peripheral support portion  92  are engaged with each other, the first inner friction materials  611  are supported so as to be slidable in the axial direction L with their rotation relative to the inner peripheral support portion  92  being restricted. In the present embodiment, the second friction material support portion  512  is formed so as to extend to the second side L 2  in the axial direction from the turbine housing portion  520  of the rotary housing  51 . The second friction material support portion  512  is connected to the turbine housing portion  520  so as to rotate integrally with the turbine housing portion  520 . In this example, the turbine housing portion  520  extends up to the inner side R 1  in the radial direction with respect to the first friction member  61  of the disconnecting engagement device  6 , and the end of the turbine housing portion  520  on the inner side R 1  in the radial direction and the end of the second friction material support portion  512  on the first side L 1  in the axial direction are connected by welding. 
     The fixing portion  93  is connected to the turbine housing portion  520  so as to rotate integrally with the turbine housing portion  520 . In the illustrated example, the fixing portion  93  is connected to the turbine housing portion  520  with rivets while being in abutment against the turbine housing portion  520  from the second side L 2  in the axial direction. The fixing portion  93  extends along the radial direction R so as to connect the outer peripheral support portion  91  and the inner peripheral support portion  92 . In the present embodiment, the fixing portion  93  is formed so as to connect the end of the outer peripheral support portion  91  on the first side L 1  in the axial direction and the end of the inner peripheral support portion  92  on the first side L 1  in the axial direction. 
     In the present embodiment, an oil passage P 1  is formed between the inner peripheral support portion  92  and the second friction material support portion  512  in the radial direction R. In this example, a plurality of spline grooves engaged with the plurality of spline grooves formed in the outer peripheral portion of the second friction material support portion  512  is formed in the inner peripheral portion of the inner peripheral support portion  92  so as to extend in the axial direction L and to be distributed in the circumferential direction. The oil passage P 1  is formed between the spline grooves of the second friction material support portion  512  and the spline grooves of the inner peripheral support portion  92 . Although illustration is omitted, in the present embodiment, a through hole P 2  extending through the inner peripheral support portion  92  in the radial direction R is formed so as to communicate with the oil passage P 1 . As a result, oil supplied to the oil passage P 1  flows to the first friction member  61  of the disconnecting engagement device  6  through the through hole P 2  in the inner peripheral support portion  92 . Thus, the first friction member  61  can be lubricated appropriately. 
     In the present embodiment, the guide member  30  is provided to guide the oil to the oil passage P 1 . In the present embodiment, the guide member  30  has a tubular shape having an axis along the axial direction L so as to extend from the first piston portion  62  toward the oil passage P 1 . In the illustrated example, the guide member  30  is connected to the first sliding portion  621  of the first piston portion  62  so as to rotate integrally with the first sliding portion  621  while being in contact with, from the inner side R 1  in the radial direction, a part of the first sliding portion  621  that extends along the axial direction L. In the present embodiment, along with rotation of the transmission input shaft  31  having a tubular shape having an axis along the axial direction L, the oil is supplied to a space between the cylinder forming portion  513  of the rotary housing  51  and each of the connecting portion  13  of the input member  1  and the first piston portion  62  from the inside of the transmission input shaft  31  through a radial communication hole P 3 . Then, the oil flows through the space between the cylinder forming portion  513  and each of the connecting portion  13  and the first piston portion  62  to the outer side R 2  in the radial direction, and reaches the guide member  30 . The oil that has reached the guide member  30  flows along the inner peripheral surface of the guide member  30  to the first side L 1  in the axial direction, and is supplied to the oil passage P 1  formed between the inner peripheral support portion  92  and the second friction material support portion  512  in the radial direction R. 
     Although illustration and description are omitted in the first embodiment, as shown in  FIG.  4   , the vehicle drive device  100  includes a rotation sensor  8  that detects the rotation of the rotor Ro of the rotary electric machine MG. In the present embodiment, the rotation sensor  8  includes a fixed body  81  and a rotary body  82 . 
     The fixed body  81  is fixed to the case  4 . In the present embodiment, the fixed body  81  is supported by the second support  42  of the case  4 . The rotary body  82  is connected to the rotor Ro or the member that rotates integrally with the rotor Ro so as to rotate integrally with the rotor Ro or the member. In the present embodiment, the rotary body  82  is connected to the rotary housing  51  so as to rotate integrally with the rotary housing  51 . 
     In the present embodiment, the rotary body  82  has an annular plate shape, and has a plurality of teeth distributed in the circumferential direction. The fixed body  81  detects the plurality of teeth of the rotary body  82  as a detection target, and outputs a signal based on the detection target. In the illustrated example, the plurality of teeth is formed on the inner peripheral portion of the rotary body  82 . The outer peripheral portion of the rotary body  82  is supported by the pump housing portion  519  of the rotary housing  51 . In the illustrated example, the pump housing portion  519  has a shape that bulges to the first side L 1  in the axial direction with respect to the radially extending portion  518 , and the rotary body  82  is arranged on the inner side R 1  in the radial direction with respect to the pump housing portion  519  at a position where the rotary body  82  overlaps the pump housing portion  519  in the radial view along the radial direction R. The fixed body  81  is arranged so as to face the rotary body  82  from the first side L 1  in the axial direction. 
     In this example, an inductive sensor (inductive proximity sensor) is used as the rotation sensor  8 . The type of the rotation sensor  8  is not limited to the above. The rotation sensor  8  may be provided by using various sensors such as a resolver, a Hall element sensor, an encoder, and a magnetic rotation sensor. 
     3. Other Embodiments 
     (1) In the first embodiment, description has been given of the exemplary configuration in which the seal member S is arranged between the tubular support portion  411  of the first support  41  in the case  4  and the inner tubular portion  12  of the input member  1  in the radial direction R. The size of the space between the tubular support portion  411  and the inner tubular portion  12  in the radial direction R where the seal member S is arranged is not particularly limited. For example, as shown in  FIG.  6   , the distance in the radial direction R between the tubular support portion  411  and the inner tubular portion  12  may be larger than that in the first embodiment. The seal member S used in this case has a larger thickness in the radial direction R (difference between the outside diameter and the bore diameter) than that in the first embodiment. In the example shown in  FIG.  6   , the seal member S is arranged so as to overlap the second bearing B 2  in the radial view. 
     (2) In the above embodiments, description has been given of the exemplary configuration in which the first radial support surface  13   a  is formed so as to face the inner side R 1  in the radial direction and the second radial support surface  41   a  is formed so as to face the outer side R 2  in the radial direction. However, the present disclosure is not limited to such a configuration. The first radial support surface  13   a  may be formed so as to face the outer side R 2  in the radial direction, and the second radial support surface  41   a  may be formed so as to face the inner side R 1  in the radial direction. 
     (3) In the above embodiments, description has been given of the exemplary configuration in which the first bearing B 1  and the second bearing B 2  are arranged so as to overlap each other in the radial view along the radial direction R. However, the present disclosure is not limited to such a configuration. The first bearing B 1  may be arranged on one side in the axial direction L with respect to the second bearing B 2 . 
     (4) In the above embodiments, description has been given of the exemplary configuration in which the input member  1  includes the outer tubular portion  11 , the inner tubular portion  12 , and the connecting portion  13 , the support outer peripheral surface  11  a is formed on the outer tubular portion  11 , the sealing outer peripheral surface  12   a  is formed on the inner tubular portion  12 , and the first radial support surface  13   a  is formed on the connecting portion  13 . However, the present disclosure is not limited to such a configuration. For example, the input member  1  need not include the outer tubular portion  11 , and the support outer peripheral surface  11   a  may be formed on the connecting portion  13 . 
     (5) In the above embodiments, description has been given of the exemplary configuration in which the first support  41  of the case  4  includes the tubular support portion  411  and the radially extending portion  412  and both the second radial support surface  41   a  and the sealing inner peripheral surface  41   b  are formed on the tubular support portion  411 . However, the present disclosure is not limited to such a configuration. For example, the first support  41  may further include an inner tubular support portion having a tubular shape and arranged on the inner side R 1  in the radial direction with respect to the tubular support portion  411 , the sealing inner peripheral surface  41   b  may be formed on the inner tubular support portion, and the second radial support surface  41   a  may be formed on the tubular support portion  411 . 
     (6) In the second embodiment, description has been given of the exemplary configuration in which the rotor support member  9  functioning as the second rotary member RT 2  is connected to the rotary housing  51  of the fluid coupling  5  so as to rotate integrally with the rotary housing  51 . However, the present disclosure is not limited to such a configuration. For example, the fluid coupling  5  need not be provided, and the rotor support member  9  may drivingly be connected to the transmission input shaft  31  via the second engagement device CL 2 . 
     (7) In the above embodiments, description has been given of the exemplary configuration in which at least one of the first piston portion  62  and the first hydraulic oil chamber  63  of the disconnecting engagement device  6  is arranged between the first bearing B 1  and the second bearing B 2  in the radial direction R at the position where the at least one of the first piston portion  62  and the first hydraulic oil chamber  63  overlaps at least one of the first bearing B 1  and the second bearing B 2  in the radial view along the radial direction R. However, the present invention is not limited to such a configuration. Both the first piston portion  62  and the first hydraulic oil chamber  63  may be arranged so as to overlap neither the first bearing B 1  nor the second bearing B 2  in the radial view. 
     (8) In the above embodiments, description has been given of the exemplary configuration in which the first piston portion  62  of the disconnecting engagement device  6  is arranged between the first bearing B 1  and the second bearing B 2  in the radial direction R at the position where the first piston portion  62  overlaps at least one of the first bearing B 1  and the second bearing B 2  in the radial view along the radial direction R. However, the present disclosure is not limited to such a configuration. The first piston portion  62  may be arranged so as to overlap neither the first bearing B 1  nor the second bearing B 2  in the radial view. 
     (9) In the above embodiments, description has been given of the exemplary configuration in which the lockup clutch  54  serving as the second engagement device CL 2  is arranged on the inner side R 1  in the radial direction with respect to the disconnecting engagement device  6  serving as the first engagement device CL 1  at the position where the lockup clutch  54  overlaps the disconnecting engagement device  6  in the radial view along the radial direction R. However, the present disclosure is not limited to such a configuration. The second engagement device CL 2  may be arranged on one side in the axial direction L with respect to the first engagement device CL 1 . 
     (10) In the above embodiments, description has been given of the exemplary configuration in which both the disconnecting engagement device  6  serving as the first engagement device CL 1  and the lockup clutch  54  serving as the second engagement device CL 2  are arranged on the inner side R 1  in the radial direction with respect to the rotor 
     Ro of the rotary electric machine MG at the positions where the disconnecting engagement device  6  and the lockup clutch  54  overlap the rotor Ro in the radial view along the radial direction R. However, the present disclosure is not limited to such a configuration. For example, only one of the first engagement device CL 1  and the second engagement device CL 2  may be arranged at a position where the engagement device overlaps the rotor Ro in the radial view. Both the first engagement device CL 1  and the second engagement device CL 2  may be arranged so as not to overlap the rotor Ro but overlap the stator St in the radial view along the radial direction R. Alternatively, both the first engagement device CL 1  and the second engagement device CL 2  may be arranged so as not to overlap the rotary electric machine MG in the radial view along the radial direction R. 
     (11) In the above embodiments, description has been given of the exemplary configuration in which both the first bearing B 1  and the second bearing B 2  are arranged on the inner side R 1  in the radial direction with respect to the rotor Ro of the rotary electric machine MG at the positions where the first bearing B 1  and the second bearing B 2  overlap the rotor Ro in the radial view along the radial direction R. However, the present disclosure is not limited to such a configuration. For example, only the first bearing B 1  may be arranged at a position where the first bearing B 1  overlaps the rotor Ro in the radial view, and the second bearing B 2  may be arranged at a position where the second bearing B 2  does not overlap the rotor Ro in the radial view. In this case, the second bearing B 2  may be arranged so as not to overlap the rotor Ro but overlap the stator St in the radial view. Alternatively, the second bearing B 2  may be arranged so as not to overlap the rotary electric machine MG in the radial view. 
     (12) The configurations disclosed in the above embodiments can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction. Regarding the other configurations, the embodiments disclosed herein are merely exemplary in all respects. Thus, various modifications can be made as appropriate without departing from the scope of the present disclosure. 
     [Summary of Embodiments] 
     Hereinafter, the outline of the vehicle drive device ( 100 ) described above will be described. 
     A vehicle drive device ( 100 ) includes: 
     an input member ( 1 ) drivingly connected to an internal combustion engine (EG); 
     an output member ( 2 ) drivingly connected to a wheel (W); 
     a rotary electric machine (MG) including a rotor (Ro) and functioning as a driving force source for the wheel (W); 
     a transmission ( 3 ) configured to change a speed of rotation transmitted from the rotary electric machine (MG) side and transmit the rotation to the output member ( 2 ) side; and 
     a case ( 4 ) that houses the rotary electric machine (MG) and the transmission ( 3 ), in 
     which 
     the input member ( 1 ) or a member that rotates integrally with the input member ( 1 ) is defined as a first rotary member (RT 1 ), and the rotor (Ro) or a member that rotates integrally with the rotor (Ro) is defined as a second rotary member (RT 2 ), 
     the vehicle drive device ( 100 ) includes:
     a first bearing (B 1 ) that supports the second rotary member (RT 2 ) on the first rotary member (RT 1 ) so that the second rotary member (RT 2 ) rotates relative to the first rotary member (RT 1 ); and   

     a second bearing (B 2 ) that supports the first rotary member (RT 1 ) on the case ( 4 ) so that the first rotary member (RT 1 ) rotates relative to the case ( 4 ), 
     the case ( 4 ) includes a support ( 41 ) that supports the second bearing (B 2 ), 
     the first rotary member (RT 1 ) has a support outer peripheral surface ( 11   a ) that faces an outer side (R 2 ) in a radial direction (R), and a first radial support surface ( 13   a ) that faces one side in the radial direction (R), 
     the second rotary member (RT 2 ) has a support inner peripheral surface ( 51   a ) that faces an inner side (R 1 ) in the radial direction (R), 
     the support ( 41 ) has a second radial support surface ( 41   a ) that faces the first radial support surface ( 13   a ) in the radial direction (R), 
     the first bearing (B 1 ) is arranged between the support outer peripheral surface ( 11   a ) and the support inner peripheral surface ( 51   a ) in the radial direction (R), 
     the second bearing (B 2 ) is arranged between the first radial support surface ( 13   a ) and the second radial support surface ( 41   a ) in the radial direction (R), and 
     the first bearing (B 1 ) is arranged on the inner side (R 1 ) in the radial direction (R) with respect to the rotor (Ro) at a position where the first bearing (B 1 ) overlaps the rotor (Ro) in a radial view along the radial direction (R). 
     According to this configuration, the second rotary member (RT 2 ) is supported so as to be rotatable relative to the case ( 4 ) via the first bearing (B 1 ), the first rotary member (RT 1 ), and the second bearing (B 2 ). Therefore, the second radial support surface ( 41   a ) for supporting the second bearing (B 2 ) is formed on the case ( 4 ), whereas a surface for supporting the first bearing (B 1 ) is not formed on the case ( 4 ). The support outer peripheral surface ( 11   a ) for supporting the first bearing (B 1 ) is formed on the first rotary member (RT 1 ). Thus, it is possible to avoid a configuration in which a portion for supporting the first bearing (B 1 ) and a portion for supporting the second bearing (B 2 ) are arranged side by side in the radial direction (R) on the case ( 4 ). As a result, it is easy to reduce the dimension of the vehicle drive device in the radial direction (R). 
     It is preferable that both the first bearing (B 1 ) and the second bearing (B 2 ) be arranged on the inner side (R 1 ) in the radial direction (R) with respect to the rotor (Ro) at positions where the first bearing (B 1 ) and the second bearing (B 2 ) overlap the rotor (Ro) in the radial view, and 
     it is preferable that the first bearing (B 1 ) and the second bearing (B 2 ) be arranged so as to overlap each other in the radial view. 
     According to this configuration, the dimension of the vehicle drive device ( 100 ) in the axial direction (L) can be reduced compared to a configuration in which the first bearing (B 1 ) and the second bearing (B 2 ) are arranged side by side in the axial direction (L). 
     It is preferable that the vehicle drive device ( 100 ) further include a first engagement device (CL 1 ) configured to connect or disconnect power transmission between the input member ( 1 ) and the rotary electric machine (MG), 
     it is preferable that the first engagement device (CL 1 ) include a first friction member ( 61 ), a first piston portion ( 62 ) configured to press the first friction member ( 61 ) in the axial direction (L), and a first hydraulic oil chamber ( 63 ) to which oil for operating the first piston portion ( 62 ) is supplied, and 
     it is preferable that at least one of the first piston portion ( 62 ) and the first hydraulic oil chamber ( 63 ) be arranged between the first bearing (B 1 ) and the second bearing (B 2 ) in the radial direction (R) at a position where the at least one of the first piston portion ( 62 ) and the first hydraulic oil chamber ( 63 ) overlaps at least one of the first bearing (B 1 ) and the second bearing (B 2 ) in the radial view. 
     According to this configuration, the dimension of the vehicle drive device ( 100 ) in the axial direction (L) can be reduced compared to a configuration in which both the first piston portion ( 62 ) and the first hydraulic oil chamber ( 63 ) are arranged on one side in the axial direction (L) with respect to the first bearing (B 1 ) and the second bearing (B 2 ). 
     In the configuration including the first engagement device (CL 1 ), it is preferable that the vehicle drive device ( 100 ) further include a second engagement device (CL 2 ) configured to connect or disconnect power transmission between the rotary electric machine (MG) and the transmission ( 3 ), 
     it is preferable that the second engagement device (CL 2 ) include a second friction member ( 55 ), a second piston portion ( 56 ) configured to press the second friction member ( 55 ) in the axial direction (L), and a second hydraulic oil chamber ( 57 ) to which oil for operating the second piston portion ( 56 ) is supplied, 
     it is preferable that the second engagement device (CL 2 ) be arranged on the inner side (R 1 ) in the radial direction (R) with respect to the first engagement device (CL 1 ) at a position where the second engagement device (CL 2 ) overlaps the first engagement device (CL 1 ) in the radial view, 
     it is preferable that the first piston portion ( 62 ) and the second hydraulic oil chamber ( 57 ) be arranged so as to overlap each other in the radial view, and 
     it is preferable that both the first engagement device (CL 1 ) and the second engagement device (CL 2 ) be arranged on the inner side (R 1 ) in the radial direction (R) with respect to the rotor (Ro) at positions where the first engagement device (CL 1 ) and the second engagement device (CL 2 ) overlap the rotor (Ro) in the radial view. 
     According to this configuration, the dimension of the vehicle drive device ( 100 ) in the axial direction (L) can be reduced compared to a configuration in which the second engagement device (CL 2 ) is arranged on one side in the axial direction (L) with respect to the first engagement device (CL 1 ). 
     In the configuration including the first engagement device (CL 1 ) and the second engagement device (CL 2 ), 
     it is preferable that the vehicle drive device ( 100 ) further include a fluid coupling ( 5 ) arranged in a power transmission path between the rotary electric machine (MG) and the transmission ( 3 ), 
     it is preferable that the fluid coupling ( 5 ) include a rotary housing ( 51 ) configured to rotate integrally with the rotor (Ro), and a lockup clutch ( 54 ) that is the second engagement device (CL 2 ), and 
     it is preferable that the second rotary member (RT 2 ) be the rotary housing ( 51 ) or a member that rotates integrally with the rotary housing ( 51 ). 
     According to this configuration, the support inner peripheral surface ( 51   a ) can appropriately be formed by using the rotary housing ( 51 ) of the fluid coupling ( 5 ) or the member that rotates integrally with the rotary housing ( 51 ). 
     It is preferable that the first radial support surface ( 13   a ) be formed so as to face the inner side (R 1 ) in the radial direction (R), and 
     it is preferable that the second radial support surface ( 41   a ) be formed so as to face the outer side (R 2 ) in the radial direction (R). 
     According to this configuration, a space for arranging a member between the first rotary member (RT 1 ) and the first support ( 41 ) in the radial direction (R) can easily be secured on the inner side (R 1 ) in the radial direction with respect to the second radial support surface ( 41   a ) of the first support ( 41 ) in the case ( 4 ). That is, the configuration is such that the member to be arranged between the first rotary member (RT 1 ) and the first support ( 41 ) in the radial direction (R) can easily be arranged on one side in the radial direction (R) with respect to the first bearing (B 1 ) and the second bearing (B 2 ). As a result, the dimension of the vehicle drive device ( 100 ) in the axial direction (L) can easily be reduced even in a case where a predetermined member is arranged between the first rotary member (RT 1 ) and the first support ( 41 ) in the radial direction (R). 
     INDUSTRIAL APPLICABILITY 
     The technology according to the present disclosure is applicable to a vehicle drive device including an input member drivingly connected to an internal combustion engine, an output member drivingly connected to wheels, a rotary electric machine that functions as a driving force source for the wheels, a transmission that changes the speed of rotation transmitted from the rotary electric machine side and transmits the rotation to the output member side, and a case that houses the rotary electric machine and the transmission. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
       100 : vehicle drive device,  1 : input member,  11   a : support outer peripheral surface,  13   a : first radial support surface,  2 : output member,  3 : transmission,  4 : case,  41 : first support (support),  41   a : second radial support surface,  51   a : support inner peripheral surface, RT 1 : first rotary member, RT 2 : second rotary member, B 1 : first bearing, B 2 : second bearing, MG: rotary electric machine, Ro: rotor, EG: internal combustion engine, W: wheel, R: radial direction, R 1 : inner side in radial direction, R 2 : outer side in radial direction