Patent Publication Number: US-2019178247-A1

Title: Co-rotating scroll compressor

Description:
TECHNICAL FIELD 
     The present invention relates to a co-rotating scroll compressor. 
     BACKGROUND ART 
     Conventionally, co-rotating scroll compressors have been known (see PTL 1). This includes a driving side scroll and a driven side scroll that rotates synchronously with the driving side scroll, and offsets a driven shaft that supports the rotation of the driven side scroll by a revolute radius, with respect to a drive shaft that rotates the driving side scroll, and rotates the drive shaft and the driven shaft at a same angular velocity in a same direction. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] the Publication of Japanese Patent No. 5443132 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the co-rotating scroll compressor as in PTL 1, deformation is generated by a centrifugal force in a scroll part. In particular, in the case of high-speed rotation, the deformation caused by the centrifugal force can not be ignored. 
     In addition, when a temperature rises during the operation of the co-rotating scroll compressor, thermal stress may be generated in the scroll part. 
     The present invention has been made in view of such circumstances, and an object thereof is to provide a co-rotating scroll compressor capable of alleviating deformation caused by a centrifugal force generated in a scroll part. 
     Another object of the present invention is to provide the co-rotating scroll compressor capable of alleviating thermal stress generated in the scroll part. 
     Solution to Problem 
     To solve the above problem, a co-rotating scroll compressor of the present invention employs the following solutions. 
     The co-rotating scroll compressor according to the present invention includes, a driving side scroll member rotatably driven by a drive part, having a plurality of spiral driving side wall bodies installed with a predetermined angular interval around the center of a driving side end plate, a driven side scroll member installed with the predetermined angular interval around the center of a driven side end plate, having the number of spiral driven side wall bodies corresponding to each of the driving side wall bodies, and forming compression spaces by engaging each of the driven side wall bodies with the corresponding driving side wall bodies, a synchronous driving mechanism transmitting driving force from the driving side scroll member to the driven side scroll member so that the driving side scroll member and the driven side scroll member synchronously revolve, a first driving side bearing and a second driving side bearing rotatably supporting a shaft part at one end side and the other end side in an axial direction of the driving side scroll member, and a first driven side bearing and a second driven side bearing rotatably supporting the shaft part at one end side and the other end side in an axial direction of the driven side scroll member, a preload is applied to the shaft part so that an axial clearance in a second driving side bearing direction is eliminated in the first driving side bearing, and a preload is applied to the shaft part so that an axial clearance in a first driving side bearing direction is eliminated in the second driving side bearing, and/or a preload is applied to the shaft part so that an axial clearance in a second driven side bearing direction is eliminated in the first driven side bearing, and a preload is applied to the shaft part so that an axial clearance in a first driven side bearing direction is eliminated in the second driven side bearing. 
     Each of the driving side wall bodies arranged with the predetermined angular interval around the center of the end plate of the driving side scroll member is engaged with the corresponding driven side wall body of the driven side scroll member. Thereby, a plurality of pairs each including one driving side wall body and one driven side wall body are provided, and a scroll compressor having the wall body formed by a plurality of spirals is constituted. The driving side scroll member is rotatably driven by the drive part, and the driving force transmitted to the driving side scroll member is transmitted to the driven side scroll member via the synchronous driving mechanism. As a result, the driven side scroll member rotates and performs rotation with respect to the driving side scroll member in the same direction at the same angular speed. In this way, the co-rotating scroll compressor is provided in which both the driving side scroll member and the driven side scroll member rotate. 
     In the driving side scroll member, the first driving side bearing and the second driving side bearing rotatably support the shaft parts on one end side and the other end side in the axial direction. The rotation of the driving side scroll member generates a centrifugal force to deform the driving side wall body of the driving side scroll member radially outward. As described above, the radially outward deformation of the outer peripheral side of the driving side scroll member tends to cause the driving side scroll member to deform to decrease a distance to axial direction between the shaft part supported by the first driving side bearing and the shaft part supported by the second driving side bearing. Allowing such deformation further increases the deformation radially outward on the outer peripheral side of the driving side scroll member. Therefore, a preload is applied to the shaft part so that an axial clearance in the second driving side bearing direction is eliminated in the first driving side bearing, and a preload is applied to the shaft part so that an axial clearance in the first driving side bearing direction is eliminated in the second driving side bearing. Thereby, suppression of the deformation in which the distance to axial direction between both the shaft parts supported by each of the driving side bearings decreases, can alleviate stress generated in the driving side scroll member, further suppress leakage of compressed fluid generated by the deformation of the driving side scroll member. 
     Similarly, in the driven side scroll member, the first driven side bearing and the second driven side bearing rotatably support the shaft parts on one end side and the other end side in the axial direction. The rotation of the driven side scroll member generates the centrifugal force to deform the driven side wall body of the driven side scroll member radially outward. As described above, the radially outward deformation of the outer peripheral side of the driven side scroll member tends to cause the driven side scroll member to deform to decrease a distance to axial direction between the shaft part supported by the first driven side bearing and the shaft part supported by the second driven side bearing. Allowing such deformation further increases the deformation radially outward on the outer peripheral side of the driven side scroll member. Therefore, a preload is applied to the shaft part so that an axial clearance in the second driven side bearing direction is eliminated in the first driven side bearing and a preload is applied to the shaft part so that an axial clearance in the first driven side bearing direction is eliminated in the second driven side bearing. Thereby, the suppression of the deformation in which the distance to axial direction between both the shaft parts supported by each of the driven side bearings decreases, can alleviate the stress generated in the driven side scroll member, further suppress the leakage of compressed fluid generated by the deformation of the driven side scroll member. 
     Further, the co-rotating scroll compressor according to the present invention includes a driving side support member arranged via the driven side end plate, fixed to a distal end side in the axial direction of the driving side wall body and rotates together with the driving side scroll member and a driven side support member arranged via the driving side end plate, fixed to a distal end side in the axial direction of the driven side wall body and rotates together with the driven side scroll member, and the first driving side bearing supports the shaft part of the driving side scroll member, the second driving side bearing supports the shaft part of the driving side support member, the first driven side bearing supports a bearing of the driven side support member, and the second driven side bearing supports the shaft part of the driven side scroll member. 
     The shaft part of the driving side scroll member is supported by the first driving side bearing and the shaft part of the driving side support member is supported by the second driving side bearing. Further, as described above, it is constituted that applying a preload to the first driving side bearing and the second driving side bearing suppresses the deformation in which the distance to axial direction between both the shaft parts supported by each of the driving side bearings decreases. Therefore, it is possible to suppress a fixing part of the distal end of the wall body of the driving side scroll member and the driving side support member from being deformed radially outward due to the centrifugal force. 
     The shaft part of the driven side support member is supported by the first driven side bearing and the shaft part of the driven side scroll member is supported by the second driven side bearing. Further, as described above, it is constituted that applying a preload to the first driven side bearing and the second driven side bearing suppresses the deformation in which the distance to axial direction between both the shaft parts supported by each of the driven side bearings decreases. Therefore, it is possible to suppress the fixing part of the distal end of the wall body of the driven side scroll member and the driven side support member from being deformed radially outward due to the centrifugal force. 
     Further, in the co-rotating scroll compressor according to the present invention, the distal end side of the driving side wall body and the driving side support member are fixed to allow displacement in the axial direction, and each of the shaft parts is supported by a first driving side bearing and a second driving side bearing, to allow an increase in the distance between the shaft part supported by the first driving side bearing and the shaft part supported by the second driving side bearing, and/or the distal end of the driven side wall body and the driven side support member are fixed to allow the displacement in the axial direction, and each of the shaft parts is supported by the first driven side bearing and the second driven side bearing, to allow the increase in the distance between the shaft part supported by the first driven side bearing and the shaft part supported by the second driven side bearing. 
     The increase of temperature during the operation in the co-rotating scroll compressor tends to cause the driving side scroll member and the driving support member to thermally expand, and deform to increase the distance to axial direction between both the shaft parts supported by each of the driving side bearings. The restraint of the deformation leads to the increase in thermal stress generated in the driving side scroll member and the driving side support member. Therefore, the distal end side of the driving side wall body and the driving side support member are fixed to allow the displacement in the axial direction, and each of the shaft parts is supported by the first driving side bearing and the second driving side bearing, to allow the increase in the distance between both the shaft parts supported by each of the driving side bearings. As a result, the distance between both the shaft parts supported by each of the driving side bearings can be increased according to the thermal expansion, so that the generation of the thermal stress can be suppressed. 
     For example, the distal end side of the driving side wall body and the driving side support member may be slidably fixed by pins to allow the displacement in the axial direction. Further, for example, a preload direction of each driving side bearing may be set to cause the distal end side of the driving side wall body and the driving side support member to be displaceable in a direction in which the distance between both shaft parts supported by each driving side bearing increases. 
     Similarly for the driven side, the increase of temperature during the operation in the co-rotating scroll compressor tends to cause the driven side scroll member and the driven support member to thermally expand, and deform to increase the distance to axial direction between both the shaft parts supported by each of the driven side bearings. The restraint of the deformation leads to the increase in the thermal stress generated in the driven side scroll member and the driven side support member. Therefore, the distal end side of the driven side wall body and the driven side support member are fixed to allow the displacement in the axial direction, and each of the shaft parts is supported by the first driven side bearing and the second driven side bearing, to allow the increase in the distance between both the shaft parts supported by each of the driven side bearings. As a result, the distance between both the shaft parts supported by each of the driven side bearings can be increased according to the thermal expansion, so that the generation of the thermal stress can be suppressed. 
     For example, the distal end side of the driven side wall body and the driven side support member may be slidably fixed by pins to allow the displacement in the axial direction. Further, for example, the preload direction of each driven side bearing may be set to cause the distal end side of the driven side wall body and the driven side support member to be displaceable in a direction in which the distance between both shaft parts supported by each driven side bearing increases. 
     Further, the co-rotating scroll compressor provided with, the driving side scroll member including a first driving side scroll part having the first driving side end plate and the first driving side wall body, driven by the drive part, a second driving side scroll member having a second driving side end plate and a second driving side wall body, and a fixed portion of wall fixing the first driving side wall body and the second driving side wall body in a state in which the distal ends of the first driving side wall body and the second driving side wall body in the axial direction face each other, the driven side scroll member including a first driven side wall body provided on one side face of the driven side end plate, engaged with the first driving side wall body, and a second driven side wall body provided on the other side face of the driven side end plate, engaged with the second driving side wall body, a first support member arranged via the first driving side end plate, fixed to a distal end side in the axial direction of the first driven side wall body and rotating together with the first driven side wall body and a second support member arranged via the second driving side end plate, fixed to the distal end side in the axial direction of the second driven side wall body and rotating together with the second driven side wall body, wherein the first driving side bearing supports a shaft part of the first driving side scroll part, the second driving side bearing supports a shaft part of the second driving side scroll part, the first driven side bearing supports a bearing of the first support member, and the second driven side bearing supports a shaft part of the second support member. 
     The shaft part of the first driving side scroll part is supported by the first driving side bearing and the shaft part of the second driving side scroll part is supported by the second driving side bearing. Further, as described above, it is constituted that applying a preload to the first driving side bearing and the second driving side bearing suppresses the deformation in which the distance to axial direction between both the shaft parts supported by each of the driving side bearings decreases. Therefore, it is possible to suppress the fixed portion of wall of the driving side scroll member from being deformed radially outward due to the centrifugal force. 
     The shaft part of the first support member is supported by the first driven side bearing and the shaft part of the second support member is supported by the second driven side bearing. Further, as described above, it is constituted that applying a preload to the first driven side bearing and the second driven side bearing suppresses the deformation in which the distance to axial direction between both the shaft parts supported by each of the driven side bearings decreases. Therefore, it is possible to suppress the fixing part of the distal end of each driven side wall body and each of the driven side support members from being deformed radially outward due to the centrifugal force. 
     Further, in co-rotating scroll compressor, the fixed portion of wall is fixed to allow the displacement in the axial direction, and each of the shaft parts is supported by a first driving side bearing and a second driving side bearing, to allow the increase in the distance between the shaft part supported by the first driving side bearing and the shaft part supported by the second driving side bearing, and/or the distal end of each of the driven side wall bodies and each of the support members is fixed to allow the displacement in the axial direction, and each of the shaft parts is supported by a first driven side bearing and a second driven side bearing, to allow the increase in the distance between the shaft part supported by the first driven side bearing and the shaft part supported by the second driven side bearing. 
     The increase of temperature during the operation in the co-rotating scroll compressor tends to cause the driving side scroll member to thermally expand, and deform to increase the distance to axial direction between both the shaft parts supported by each of the driving side bearings. The restraint of the deformation leads to the increase in the thermal stress generated in the driving side scroll member. Therefore, the fixed portion of wall is fixed to allow the displacement in the axial direction, and each of the shaft parts is supported by the first driving side bearing and the second driving side bearing, to allow the increase in the distance between both the shaft parts supported by each of the driving side bearings. As a result, the distance between both the shaft parts supported by each of the driving side bearings can be increased according to the thermal expansion, so that the generation of the thermal stress can be suppressed. 
     For example, as for the fixed portion of wall, a pin is used to allow the displacement in the axial direction. Further, for example, the preload direction of each driving side bearing may be set to be displaceable in the direction in which the distance between both shaft parts supported by each driving side bearing increases. 
     Similarly for the driven side, the increase of temperature during the operation in the co-rotating scroll compressor tends to cause the driven side scroll member and the driven side support member to thermally expand, and deform to increase the distance to axial direction between both the shaft parts supported by each of the driven side bearings. The restraint of the deformation leads to the increase in the thermal stress generated in the driven side scroll member and each of the support members. Therefore, the distal end of each driven side wall body and each of the support members are fixed to allow the displacement in the axial direction, and each of the shaft parts is supported by the first driven side bearing and the second driven side bearing, to allow the increase in the distance between both the shaft parts supported by each of the driven side bearings. As a result, the distance between both the shaft parts supported by each of the driven side bearings can be increased according to the thermal expansion, so that the generation of the thermal stress can be suppressed. 
     For example, the distal end of each driven side wall body and each of the support members may be fixed by pins to allow it to displace in the axial direction. Further, for example, the preload direction of each driven side bearing may be set to be displaceable in a direction in which the distance between both shaft parts supported by each driven side bearing increases. 
     Further, the co-rotating scroll compressor according to the present invention includes a first housing having a bearing fixing part to which the first driving side bearing and the first driven side bearing are fixed, and a second housing contacted against and fixed to the first housing in the axial direction, and having a bearing fixing part to which the second driving side bearing and the second driven side bearing are fixed. Contacting the first housing and the second housing each other in the axial direction to be fixed applies a preload to both the driving side bearings and/or both the driven side bearings. 
     Contacting the first housing and the second housing each other in the axial direction to be fixed applies a preload to the bearings, so that it is unnecessary to provide a preload member (such as a nut) for applying a preload. As a result, the number of parts can be reduced, and assembling property is improved. 
     Further, in the co-rotating scroll compressor according to the present invention, the first driving side bearing is provided on the shaft part on the opposite side sandwiching the drive part as seen from the driving side end plate of the driving side scroll member. 
     The first driving side bearing is provided on the shaft part on the opposite side sandwiching the drive part (for example, an electric motor) as seen from the driving side end plate. Thereby, it is not necessary to provide the driving side shaft part between the driving side end plate and the drive part, and the number of parts can be reduced. Even if the driving side shaft part is provided between the driving side end plate and the drive part, applying a preload by the first driving side bearing provided on the opposite side of the drive part can reduce a burden on the driving side shaft part provided between the driving side end plate and the drive part. 
     Advantageous Effects of Invention 
     A preload is applied to the shaft part to eliminate an axial clearance between each of the bearings, so that it is possible to alleviate a change caused by the centrifugal force generated in the scroll member. 
     Fixing to allow the displacement in the axial direction of the fixing part and allowance of the increase in the distance between the shafts supported by each of the bearings can suppress the generation of the thermal stress. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a longitudinal section view showing a co-rotating scroll compressor according to a first embodiment of the present invention. 
         FIG. 2  is a plan view showing a driving side scroll member of  FIG. 1 . 
         FIG. 3  is a plan view showing a driven side scroll member of  FIG. 1 . 
         FIG. 4  is a longitudinal section view showing a contact angle caused by a preload of a bearing shown in  FIG. 1 . 
         FIG. 5  shows deformation caused by centrifugal force of the driving side scroll member, wherein  FIG. 5( a )  is a schematic diagram showing a longitudinal section view according to a reference example, and  FIG. 5( b )  is a schematic diagram showing a longitudinal section view according to the first embodiment. 
         FIG. 6  shows deformation caused by a thermal expansion of the driving side scroll member,  FIG. 6( a )  is a schematic view showing a longitudinal section view according to a reference example, and  FIG. 6( b )  is a schematic view showing a longitudinal section view according to the first embodiment. 
         FIG. 7  is a longitudinal section view showing a co-rotating scroll compressor according to a second embodiment of the present invention. 
         FIG. 8  is a longitudinal section view showing Modification 1 of how a preload is applied to bearings of a co-rotating scroll compressor. 
         FIG. 9  is a longitudinal section view showing an example in which a position of a preload member is changed with respect to  FIG. 8 . 
         FIG. 10  is a longitudinal section view showing an example in which the position of the preload member is changed with respect to  FIG. 8 . 
         FIG. 11  is a table showing a combination of fitting of the respective bearings and presence or absence of the preload member of Modification 1. 
         FIG. 12  is a longitudinal section view showing Modification 2 of how a preload is applied to the bearings of the co-rotating scroll compressor. 
         FIG. 13  is a table showing a combination of fitting of the respective bearings and presence or absence of the preload member of Modification 2. 
         FIG. 14  is a longitudinal section view showing Modification 3 of how a preload is applied to the bearings of the co-rotating scroll compressor. 
         FIG. 15  is a table showing a combination of fitting of the respective bearings and presence or absence of the preload member of Modification 3. 
         FIG. 16  is a longitudinal section view showing Modification 4 of how a preload is applied to the bearings of the co-rotating scroll compressor. 
         FIG. 17  is a table showing a combination of fitting of the respective bearings and presence or absence of the preload member of Modification 4. 
         FIG. 18  is a longitudinal section view showing Modification 5 of how a preload is applied to the bearings of the co-rotating scroll compressor. 
         FIG. 19  is a table showing a combination of fitting of the respective bearings and presence or absence of the preload member of Modification 5. 
         FIG. 20  is a longitudinal section view showing Modification 6 of how a preload is applied to the bearings of the co-rotating scroll compressor. 
         FIG. 21  is a table showing a combination of fitting of the respective bearings and presence or absence of the preload member of Modification 6. 
         FIG. 22  is a longitudinal section view showing Modification 7 of how a preload is applied to the bearings of the co-rotating scroll compressor. 
         FIG. 23  is a table showing a combination of fitting of the respective bearings and presence or absence of the preload member of Modification 7. 
         FIG. 24  is a longitudinal section view showing Modification 8 of the co-rotating scroll compressor of  FIG. 1 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
     Hereinafter, a first embodiment of the present invention will be described with reference to  FIG. 1  or the like. 
       FIG. 1  shows a co-rotating scroll compressor  1 A. The co-rotating scroll compressor  1 A can be used as a supercharger for compressing combustion air (fluid) supplied to an internal combustion engine such as vehicle engines. 
     The co-rotating scroll compressor  1 A includes a housing  3 , a motor (drive part)  5  housed on one end side of the housing  3 , a driving side scroll member  70  and a driven side scroll member  90  housed on the other end side of the housing  3 . 
     The housing  3  has a substantially cylindrical shape and includes a motor housing part (first housing)  3   a  housing the motor  5  and a scroll housing part (second housing)  3   b  housing the scroll members  7  and  9 . 
     Cooling fins  3   c  cooling the motor  5  are provided on the outer periphery of the motor housing part  3   a . A discharge port  3   d  discharging compressed air is formed at an end part of the scroll housing part  3   b . Although not shown in  FIG. 1 , the housing  3  is provided with an air intake port for drawing in air. 
     The scroll housing part  3   b  of the housing  3  is divided by a dividing face P positioned substantially at the center in the axial direction of the scroll members  70  and  90 . As shown in  FIG. 4  to be described later, the housing  3  is provided with a flange part (fastening part)  30  protruding outward at a predetermined position in a circumferential direction. Bolts  32  as fastening means are fixed trough the flange part  30  so that the dividing face P is fastened. 
     The electric power supplied from the power supply source which is not shown drives the motor  5 . An instruction from a control unit which is not shown controls rotation of the motor. A stator  5   a  of the motor  5  is fixed to the inner peripheral side of the housing  3 . A rotor  5   b  of the motor  5  rotates around a driving side rotation axis CL 1 . A drive shaft  6  extending on the driving side rotation axis CL 1  is connected to the rotor  5   b . The drive shaft  6  is connected to a first driving side shaft part  7   c  of the driving side scroll member  70 . 
     At the rear end (right end in  FIG. 1 ) of the drive shaft  6 , that is, the end part of the drive shaft  6  opposite to the driving side scroll member  70 , a rear end bearing  17  that rotatably supports the drive shaft  6  between the drive shaft  6  and the housing  3  is provided. 
     The driving side scroll member  70  includes a first driving side scroll part  71  on the motor  5  side and a second driving side scroll part  72  on the discharge port  3   d  side. 
     The first driving side scroll part  71  includes a first driving side end plate  71   a  and a first driving side wall body  71   b.    
     The first driving side end plate  71   a  is connected to the first driving side shaft part  7   c  connected to the drive shaft  6 , and extends in a direction orthogonal to the driving side rotation axis CL 1 . The first driving side shaft part  7   c  is rotatably provided with respect to the housing  3  via a first driving side bearing  11  which is an angular ball bearing. 
     The first driving side end plate  71   a  has a substantially disk shape in a plan view. As shown in  FIG. 2 , three, that is, triple spirals of the first driving side wall bodies  71   b  which are formed to spiral are provided on the first driving side end plate  71   a . The first driving side wall bodies  71   b  having triple spirals are arranged at equal intervals around the driving side rotation axis CL 1 . Winding end parts  71   e  of the first driving side wall bodies  71   b  are not fixed to the other wall parts, but are independent from each other. That is, no wall part is provided to reinforce the first driving side wall bodies  71   b  by connecting the winding end parts  71   e  together. 
     As shown in  FIG. 1 , the second driving side scroll part  72  includes a second driving side end plate  72   a  and a second driving side wall body  72   b . The second driving side wall body  72   b  has triple spirals similarly to the above-described first driving side wall body  71   b  (see  FIG. 2 ). 
     A second driving side shaft part  72   c  extending in a direction of the driving side rotation axis CL 1  is connected to the second driving side end plate  72   a . The second driving side shaft part  72   c  is rotatably provided with respect to the housing  3  via a second driving side bearing  14  which is the angular ball bearing. On the side of the inner ring of the second driving side bearing  14 , a preload member  14   a  such as a nut, a disk spring is provided. The preload member  14   a  is attached to the second driving side shaft part  72   c  and is fixed to press the inner ring of the second driving side bearing  14  toward the first driving side bearing  11  side. As a result, an axial clearance between the enlarged diameter shoulder part of the second driving side shaft part  72   c  and the side face of the second driving side bearing  14  is made zero. 
     A discharge port  72   d  is formed on the second driving side shaft part  72   c  along the driving side rotation axis CL 1 . 
     The first driving side scroll part  71  and the second driving side scroll part  72  are fixed in a state in which the distal ends (free ends) of the wall bodies  71   b  and  72   b  face each other. The first driving side scroll part  71  and the second driving side scroll part  72  are fixed to each other by pins (fixed portion of wall)  31  fastened to the flange parts  73  provided at a plurality of positions in the circumferential direction to protrude outward in the radial direction. Fixing by the pin  31  allows the first driving side scroll part  71  and the second driving side scroll part  72  to move in the direction away from each other along the axial direction (horizontal direction in  FIG. 1 ). 
     The driven side scroll member  90  has a driven side end plate  90   a  provided substantially at the center in the axial direction (horizontal direction in the drawing). A through hole  90   h  is formed in the center of the driven side end plate  90   a  so that the compressed air flows to the discharge port  72   d.    
     On both sides of the driven side end plate  90   a , driven side wall bodies  91   b  and  92   b  are provided, respectively. The first driven side wall body  91   b  installed on the motor  5  side from the driven side end plate  90   a  is engaged with the first driving side wall body  71   b  of the first driving side scroll part  71 , and the second driven side wall body  92   b  installed on the discharge port  3   d  side from the driven side end plate  90   a  is engaged with the second driving side wall body  72   b  of the second driving side scroll part  72 . 
     As shown in  FIG. 3 , three, that is, triple spirals of the first driven side wall bodies  91   b  having the outer peripheral end part  91   e  are provided. The driven side wall bodies  9   b  having triple spirals are arranged at equal intervals around the driven side rotation axis CL 2 . The second driven side wall body  92   b  has also the same configuration. 
     A first support member  33  and a second support member  35  are provided on both ends of the driven side scroll member  90  in the axial direction (horizontal direction in the drawing). The first support member  33  is arranged on the motor  5  side and the second support member  35  is arranged on the discharge port  3   d  side. The first support member  33  is fixed to the distal end (free end) of the first driven side wall body  91   b  by a pin  25   a , and the second support member  35  is fixed to the distal end (free end) of the second driven side wall body  92   b  by a pin  25   b . Fixing the pins  25   a  and  25   b  causes the wall bodies  91   b  and  92   b  and the support members  33  and  35  to move in the direction away from each other along the axial direction (horizontal direction in  FIG. 1 ). 
     On the center shaft side of the first support member  33 , there is provided a first support member shaft part  33   a , which is fixed to the housing  3  via a first support member bearing (first driven side bearing)  37  which is the angular ball bearing. On the center shaft side of the second support member  35 , there is provided a second support member shaft part  35   a , which is fixed to the housing  3  via a second support member bearing (second driven side bearing)  38  which is the angular ball bearing. As a result, the driven side scroll member  90  rotates around the driven side rotation axis CL 2  via each of the support members  33  and  35 . 
     A pin ring mechanism (synchronous driving mechanism)  15  is provided between the first support member  33  and the first driving side end plate  71   a . That is, a ring member  15   a  is provided on the first driving side end plate  71   a , and a pin member  15   b  is provided on the first support member  33 . The pin ring mechanism  15  is used as the synchronous driving mechanism transmitting driving force from the driving side scroll member  70  to the driven side scroll member  90  so that both the scroll members  70  and  90  synchronously revolve. 
     A pin ring mechanism (synchronous driving mechanism)  15  is provided between the second support member  35  and the second driving side end plate  72   a . That is, a ring member  15   a  is provided on the second driving side end plate  72   a , and a pin member  15   b  is provided on the second support member  35 . The pin ring mechanism  15  is used as the synchronous driving mechanism transmitting the driving force from the driving side scroll member  70  to the driven side scroll member  90  so that both the scroll members  70  and  90  synchronously revolve. 
     In  FIG. 4 , preload directions of each of the bearings  11 ,  14 ,  37  and  38  are shown. The preload direction (contact angle caused by a preload) is indicated by black thick solid lines on the bearings  11 ,  14 ,  37  and  38 . 
     In the second driving side bearing  14 , a preload is applied to the second driving side shaft part  72   c  by the preload member  14   a  so that the clearance on the inner ring side of the first driving side bearing  11  side (right side in  FIG. 4 ) becomes zero. That is, the right side face of the inner ring of the second driving side bearing  14  contacts against the left side face of the enlarged diameter part of the second driving side shaft part  72   c.    
     In the first driving side bearing  11 , a preload is applied to the first driving side shaft part  7   c  so that the clearance on the inner ring side of the second driving side bearing  14  side (left side in  FIG. 4 ) becomes zero. That is, the left side face of the inner ring of the first driving side bearing  11  contacts against the right side face of the enlarged diameter part of the first driving side shaft part  7   c.    
     Therefore, the first driving side bearing  11  and the second driving side bearing  14  are in a DB (back surface combination) preloading relation. As described above, the restraint in the axial direction of the driving side scroll member  70  by each of the inner rings of the first driving side bearing  11  and the second driving side bearing  14  suppresses deformation in the direction in which the first driving side shaft part  7   c  and the second driving side shaft part  72   c  of the driving side scroll member  70  approaches each other. 
     Further, as described above, the application of the DB preload allows the deformation in the direction in which the distance between the inner ring of the first driving side bearing  11  and the inner ring of the second driving side bearing  14  increases. 
     A preload is applied to the first support member shaft part  33   a  so that the outer ring is urged toward the second support member bearing  38  (left direction in  FIG. 4 ) in the first support member bearing  37 . A preload is applied to the second support member shaft part  35   a  so that the outer ring is urged toward the first support member bearing  37  (right direction in  FIG. 4 ) in the second support member bearing  38 . In this manner, the first support member bearing  37  and the second support member bearing  38  are in a DF (front face combination) preloading relation. A preload is applied to the first support member bearing  37  and the second support member bearing  38  when the motor housing part  3   a  of the housing  3  and the scroll housing part  3   b  are assembled by the bolts  32 . That is, when the motor housing part  3   a  and the scroll housing part  3   b  are contacted each other in the axial direction and tightened by the bolts  32 , a preload is applied by displacing the outer rings of both bearings  37  and  38  fixed on the housing  3  side to approach each other. 
     The co-rotating scroll compressor  1 A having the above configuration operates as follows. 
     The rotation of the drive shaft  6  around the driving side rotation axis CL 1  by the motor  5  also rotates the first driving side shaft part  7   c  connected to the drive shaft  6  so that the driving side scroll member  70  rotates around the driving side rotation axis CL 1 . The rotation of the driving side scroll member  70  transmits the driving force from each of the support members  33  and  35  to the driven side scroll member  90  via the pin ring mechanism  15  and rotates the driven side scroll member  90  around the driven side rotation axis CL 2 . At this time, the movement of the pin member  15   b  of the pin ring mechanism  15  in contact with the ring member  15   a  causes both the scroll members  70  and  90  to relatively revolve. 
     The revolving motion of both the scroll members  70  and  90  causes the air sucked from the suction port of the housing  3  to be sucked from the outer peripheral sides of both the scroll members  70  and  90  and taken into the compression chambers formed by both the scroll members  70  and  90 . The compression chamber formed by the first driving side wall body  71   b  and the first driven side wall body  91   b , and the compression chamber formed by the second driving side wall body  72   b  and the second driven side wall body  92   b  are compressed separately. As the taken air moves toward the center side in each compression chamber, the volume decreases, and accordingly the air is compressed. The air compressed by the first driving side wall body  71   b  and the first driven side wall body  91   b  passes through the through hole  90   h  formed in the driven side end plate  90   a , and combines with the air compressed by the second driving side wall body  72   b  and the second driven side wall body  92   b . The combined air passes through the discharge port  72   d , and is discharged from the discharge port  3   d  of the housing  3  to the outside. The discharged compressed air is guided to an internal combustion engine which is not shown and is used as combustion air. 
     According to the present embodiment, the following operational effects are obtained. 
     In the driving side scroll member  70 , the first driving side bearing  11  and the second driving side bearing  14  rotatably support each of the shaft parts  7   c  and  72   c . The rotation of the driving side scroll member  70  generates a centrifugal force to deform the driving side wall bodies  71   b  and  72   b  of the driving side scroll member  70  radially outward (see  FIG. 5 ). As described above, the radially outward deformation of the outer peripheral side of the driving side scroll member  70  tends to cause the driving side scroll member  70  to deform to decrease a distance to axial direction between the shaft part  7   c  supported by the first driving side bearing  11  and the shaft part  72   c  supported by the second driving side bearing  14 , as shown by a broken line in  FIG. 5( a ) . Such allowance of the deformation further increases the deformation radially outward on the outer peripheral side of the driving side scroll member  70 . 
     Therefore, in the present embodiment, a preload is applied to the first driving side shaft part  7   c  so that an axial clearance in the second driving side bearing  14  direction is eliminated in the first driving side bearing  11  and a preload is applied to the second driving side shaft part  72   c  so that an axial clearance in the first driving side bearing  11  direction is eliminated in the second driving side bearing  14 . Thereby, as shown in  FIG. 5( b ) , suppression of the deformation in which a distance to axial direction between the shaft parts  7   c  and  72   c  supported by each of the driving side bearings  11  and  14  decreases, can alleviate the stress generated in the driving side scroll member  70  and further suppress leakage of the compressed air generated by the deformation of the driving side scroll member  70 . 
     An increase of temperature during the operation in the co-rotating scroll compressor  1 A tends to cause the driving side scroll member  70  to thermally expand, and deform to increase a distance to axial direction between both the shaft parts  7   c  and  72   c  supported by each of the driving side bearings  11  and  14 . The restraint of the deformation leads to the increase in the thermal stress generated in the driving side scroll member  70  as shown in  FIG. 6( a ) . 
     Therefore, the distal ends of the first driving side wall body  71   b  and the second driving side wall body  72   b  is fixed to each other by the pin  31  to allow displacement in the axial direction, and both the shaft parts  7   c  and  72   c  are supported by each of the driving side bearings  11  and  14  to allow the increase in the distance between both the shaft parts  7   c  and  72   c  supported by the driving side bearings  11  and  14 , that is, to allow the increase in the distance between the inner ring of the first driving side bearing  11  and the inner ring of the second driving side bearing  14 . As a result, as shown in  FIG. 6( b ) , the distance between both the shaft parts  7   c  and  72   c  supported by each of the driving side bearings  11  and  14  can be increased according to the thermal expansion, so that the generation of the thermal stress can be suppressed. 
     Contacting the motor housing part  3   a  and the scroll housing part  3   b  of the housing  3  each other in the axial direction to be fixed by the bolts  32  applies a preload to the first support member bearing  37  and the second support member bearing  38 , so that it is unnecessary to provide the preload member for applying a preload. As a result, the number of parts can be reduced, and assembling property is improved. 
     As for the driven side scroll member  90 , similarly to the driving side scroll member  70 , in order to alleviate the deformation caused by the centrifugal force and the thermal stress, the preload directions of the first support member bearing  37  and the second support member bearing  38  may be set. 
     Second Embodiment 
     Next, a second embodiment of the present invention will be described with reference to  FIG. 7 . 
     In the first embodiment described above, double tooth, that is, two wall bodies of  71   b ,  72   b ,  91   b  and  92   b  are provided for each of the driving side scroll member  70  and the driven side scroll member  90 , but in this embodiment, it is different in that one tooth, that is, one wall body is provided for each of the driving side scroll member  7  and the driven side scroll member  9 . The same reference numerals are given to the same configurations as those of the first embodiment, and the description thereof is omitted. 
     The co-rotating scroll compressor  1 B includes a driving side scroll member  7  housed in a motor housing part  3   a  of the housing  3  and a driven side scroll member  9  housed in the scroll housing part  3   b.    
     The driving side scroll member  7  has a driving side end plate  7   a  and a spiral driving side wall body  7   b  installed on one side of the driving side end plate  7   a . The driving side end plate  7   a  is connected to the driving side shaft part  7   c  connected to the drive shaft  6  and extends in the direction orthogonal to the driving side rotation axis line CL 1 . The driving side shaft part  7   c  is rotatably provided with respect to the housing  3  via a driving side bearing  11  which is the angular ball bearing. 
     The driving side end plate  7   a  has a substantially disk shape in a plan view. Like the first driving side wall body  71   b  shown in  FIG. 2 , the driving side scroll member  7  provided with three, that is, triple spirals of the driving side wall bodies  7   b  which are formed to spiral. The driving side wall bodies  7   b  having triple spirals are arranged at equal intervals around the driving side rotation axis CL 1 . 
     The driven side scroll member  9  is arranged to engage with the driving side scroll member  7 , and has a driven side end plate  9   a  and a spiral shaped driven side wall body  9   b  installed on one side of the driven side end plate  9   a . A driven side shaft part  9   c  extending in the direction of the driven side rotational axis CL 2  is connected to the driven side end plate  9   a . The driven side shaft part  9   c  is rotatably provided with respect to the housing  3 , via a driven side bearing  13  which is the angular ball bearing. 
     The driven side end plate  9   a  has a substantially disk shape in a plan view. Like the first driven side wall body  91   b  shown in  FIG. 3 , the driven side scroll member  9  is provided with three, that is, triple spirals of the driven side wall bodies  9   b  which are formed to spiral. The driven side wall bodies  9   b  having triple spirals are arranged at equal intervals around the driven side rotation axis CL 2 . A discharge port  9   d  discharging the compressed air is formed substantially at the center of the driven side end plate  9   a . The discharge port  9   d  communicates with a discharge port  3   d  formed in the housing  3 . 
     A driving side support member  20  is fixed to the distal end (free end) of the driving side wall body  7   b  of the driving side scroll member  7  via a pin  24   a . A driven side scroll member  9  is sandwiched between the driving side support member  20  and the driving side scroll member  7 . Therefore, the driven side end plate  9   a  is arranged to face the driving side support member  20 . 
     The driving side support member  20  has a driving side support member shaft part  20   a  on the center side, which is rotatably attached to the housing  3  via a driving side support member bearing  26  which is the angular ball bearing. As a result, the driving side support member  20  rotates around the driving side rotation axis CL 1  like the driving side scroll member  7 . 
     A pin ring mechanism  15  is provided between the driving side support member  20  and the driven side end plate  9   a . The pin ring mechanism  15  is used as the synchronous driving mechanism transmitting the driving force from the driving side scroll member  7  to the driven side scroll member  9  so that both the scroll members  7  and  9  synchronously revolve. 
     A driven side support member  22  is fixed to the distal end (free end) of the driven side wall body  9   b  of the driven side scroll member  9  via a pin  24   b . A driving side scroll member  7  is sandwiched between the driven side support member  22  and the driven side scroll member  9 . Therefore, the driving side end plate  7   a  is arranged to face the driven side support member  22 . 
     The driven side support member  22  has a driven side support member shaft part  22   a  on the center side, which is rotatably attached to the housing  3  via a driven side support member bearing  28  which is the angular ball bearing. As a result, the driven side support member  22  rotates around the driven side rotation axis CL 2  like the driven side scroll member  9 . 
     A pin ring mechanism  15  is provided between the driven side support member  22  and the driving side end plate  7   a . The pin ring mechanism  15  is used as the synchronous driving mechanism transmitting the driving force from the driving side scroll member  7  to the driven side scroll member  9  so that both the scroll members  7  and  9  synchronously revolve. 
     In  FIG. 7 , the preload directions of each of the bearings  11 ,  13 ,  26  and  28  are shown. The preload direction (contact angle caused by a preload) is indicated by black thick solid lines on the bearings  11 ,  13 ,  26  and  28 . 
     In the driven side bearing  13 , a preload is applied to the driven side shaft part  9   c  by the preload member  14   a  so that the clearance on the inner ring side of the driven side support member bearing  28  side (right side in  FIG. 7 ) becomes zero. That is, the right side face of the inner ring of the driven side bearing  13  contacts against the left side face of the enlarged diameter part of the driven side shaft part  9   c.    
     In the driven side support member bearing  28 , a preload is applied to the driven side support member shaft part  22   a  so that the clearance on the inner ring side on the driven side bearing  13  side (left side in  FIG. 7 ) becomes zero. That is, the left side face of the inner ring of the driven side support member bearing  28  contacts against the right side face of the enlarged diameter part of the driven side support member shaft part  22   a.    
     Therefore, the driven side bearing  13  and the driven side support member bearing  28  are in a DB (back surface combination) preloading relation. As described above, the restraint in the axial direction of the driven side scroll member  9  by each of the inner rings of the driven side bearing  13  and the driven side support member bearing  28  suppresses the deformation in the direction in which the driven side shaft part  9   c  of the driven side scroll member  9  and the driven side support member shaft part  22   a  approaches each other. 
     Further, as described above, the application of the DB preload allows the deformation in the direction in which the distance between the inner ring of the driven side bearing  13  and the inner ring of the driven side support member bearing  28  increases, according to the axial deformation of the driven side scroll member  9 . 
     In the driving side bearing  11 , a preload is applied to the driving side shaft part  7   c  so that the inner ring is urged in the direction of the driving side support member bearing  26  (left direction in  FIG. 7 ). In the driving side support member bearing  26 , a preload is applied to the driving side support member shaft part  20   a  so that the inner ring is urged in the outward direction of the housing  3  (left direction in  FIG. 7 ). 
     A preload is applied to the driving side bearing  11  and the driving side support member bearing  26  when the motor housing part  3   a  and the scroll housing part  3   b  of the housing  3  are assembled by the bolts  32 . That is, a preload is applied when the motor housing part  3   a  and the scroll housing part  3   b  are contacted each other in the axial direction and tightened by the bolts  32 . 
     The co-rotating scroll compressor  1 B having the above configuration operates as follows. 
     The rotation of the drive shaft around the driving side rotation axis CL 1  by the motor also rotates the driving side shaft part  7   c  connected to the drive shaft so that the driving side scroll member  7  rotates around the driving side rotation axis CL 1 . The rotation of the driving side scroll member  7  transmits the driving force from the driving side end plate  7   a  to the driven side support member  22  via the pin ring mechanism  15 . In addition, the driving force is transmitted from the driving side support member  20  to the driven side end plate  9   a  via the pin ring mechanism  15 . As a result, the driving force is transmitted to the driven side scroll member  9 , and the driven side scroll member  9  rotates around the driven side rotation axis CL 2 . At this time, the movement of the pin member  15   b  of the pin ring mechanism  15  in contact with the ring member  15   a  causes both the scroll members  7  and  9  to relatively revolve. 
     The revolving motion of both the scroll members  7  and  9  causes the air sucked from the suction port of the housing  3  to be sucked from the outer peripheral sides of both the scroll members  7  and  9 , and taken into the compression chambers formed by both the scroll members  7  and  9 . As the taken air moves toward the center side in the compression chamber, the volume decreases, and accordingly the air is compressed. The compressed air in this way passes through the discharge port  9   d  of the driven side scroll member  9 , and is discharged to the outside from the discharge port  3   d  of the housing  3 . The discharged compressed air is guided to an internal combustion engine which is not shown and used as combustion air. 
     The operational effects according to the present embodiment are as follows. 
     In the driven side scroll member  9  and the driven side scroll support member  22 , the driven side bearing  13  and the driven side support member bearing  28  rotatably support each of the shaft parts  9   c  and  22   a . The rotation of the driven side scroll member  9  generates the centrifugal force to deform the driven side wall bodies  9   b  of the driven side scroll member  9  radially outward (see, for example, the deformation shown in  FIG. 5 ). As described above, the radially outward deformation of the outer peripheral side of the driven side scroll member  9  tends to cause the driven side scroll member  9  to deform to decrease a distance to axial direction between the shaft part  9   c  supported by the driven side bearing  13  and the shaft part  22   a  supported by the driven side support member bearing  28  (see the broken line shown in  FIG. 5( a ) , for example). Such allowance of the deformation further increases the deformation radially outward on the outer peripheral side of the driven side scroll member  9 . 
     Therefore, in the present embodiment, a preload is applied to the driven side shaft part  9   c  so that an axial clearance in the driven side support member bearing  28  direction is eliminated in the driven side bearing  13  and a preload is applied to the driven side support member shaft part  22   a  so that an axial clearance in the driven side bearing  13  direction is eliminated in the driven side support member bearing  28 . Thereby, for example, similarly to the deformation shown in  FIG. 5( b ) , the suppression of the deformation in which a distance to axial direction between both the shaft parts  9   c  and  22   a  supported by each of the bearings  13  and  28  decreases, can alleviate the stress generated in the driven side scroll member  9 , further suppress the leakage of the compressed air generated by the deformation of the driven side scroll member  9 . 
     The increase of temperature during the operation in the co-rotating scroll compressor  1 B tends to cause the driven side scroll member  9  to thermally expand, and deform to increase a distance to axial direction between both the shaft parts  9   c  and  22   a  supported by each of the bearings  13  and  28 . The restraint of the deformation leads to the increase in the thermal stress generated in the driven side scroll member  9  as shown in  FIG. 6( a ) , for example. 
     Therefore, the distal ends of the driven side wall body  9   b  and the driven side support member  22  are fixed by the pin  24   b  to allow the displacement in the axial direction, and both the shaft parts  9   c  and  22   a  are supported by each of the bearings  13  and  28  to allow the increase in the distance between both the shaft parts  9   c  and  22   a  supported by each of the bearings  13  and  28 , that is, to allow the increase in the distance between the inner ring of the driven side bearing  13  and the inner ring of the driven side support member bearing  28 . As a result, for example, similarly to the deformation shown in  FIG. 6( b ) , the distance between both the shaft parts  9   c  and  22   a  supported by each of the bearings  13  and  28  can be increased according to the thermal expansion, so that the generation of the thermal stress can be suppressed. 
     Contacting the motor housing part  3   a  and the scroll housing part  3   b  of the housing  3  each other in the axial direction to be fixed by the bolts  32  applies a preload to the driving side bearing  11  and the driving side support member bearing  26 , so that it is unnecessary to provide the preload member for applying a preload. As a result, the number of parts can be reduced, and assembling property is improved. 
     As for the driving side scroll member  7 , similarly to the driven side scroll member  9 , in order to alleviate the deformation caused by the centrifugal force and the thermal stress, the preload directions of the driving side bearing  11  and the driven side support member bearing  26  may be set. 
     [Modification of how to Apply Preload] 
     In  FIG. 8  to  FIG. 23 , there is shown a modification of how a preload is applied to the bearings of the co-rotating scroll compressor  1 A shown in the first embodiment described above, that is, the modification of how a preload is applied to the both co-rotating scroll compressor of double-teeth with two wall bodies of  71   b ,  72   b ,  91   b  and  92   b  provided for each of the driving side scroll member  70  and the driven side scroll member  90 . Therefore, the same reference numerals are given to the same configurations as those of the co-rotating scroll compressor  1 A of the first embodiment, and the description thereof is omitted. 
     &lt;Modification 1&gt; 
       FIG. 8  shows a modification of how a preload is applied to the drive shaft  6  side, for the first embodiment. 
     In the second driving side bearing  14 , an inner ring is loosely fitted to be fixed to be movable in the axial direction with respect to the second drive shaft part  72   c , and the outer ring is tightly fitted to be fixed not to move in the axial direction with respect to the housing  3 . 
     In the first driving side bearing  11 , an inner ring is loosely fitted to be fixed to be movable in the axial direction with respect to the first drive shaft part  7   c  and the outer ring is tightly fitted to be fixed not to move in the axial direction with respect to the housing  3 . 
     In the rear end bearing  17  provided at the rear end (the right end in  FIG. 8 ) of the drive shaft  6 , the inner ring is loosely fitted to be fixed to be movable in the axial direction with respect to the drive shaft  6 , and the outer ring is tightly fitted to be fixed not to move in the axial direction with respect to the housing  3 . On the right side of the rear end bearing  17 , a preload member  17   a  pressing the inner ring of the rear end bearing  17  toward the driving side scroll member  70  side is provided. The preload member  17   a  is a nut or the like, and is screwed to the drive shaft  6 . The application of a preload to the inner ring of the rear end bearing  17  by the preload member  17   a  causes a load to be applied from the right side of the inner ring to the left side of the outer ring, as shown by the thick solid line in the figure. 
     The preload direction of the second driving side bearing  14  is the direction from the right side of the inner ring to the left side of the outer ring and the preload direction of the first driving side bearing  11  is the direction from the left side of the inner ring to the right side of the outer ring. A preload is applied to the second driving side bearing  14  and the first driving side bearing  12  when the motor housing part  3   a  and the scroll housing part  3   b  of the housing  3  are contacted to be fixed by the bolts  32  in the axial direction. 
     According to such a configuration, the preload member is provided only on the rear end bearing  17 , and it is not necessary to provide the preload member on the first driving side bearing  11  and the second driving side bearing  14 , so that the number of parts can be reduced. 
       FIG. 11  shows a combination of fitting of each bearing  11 ,  14  and  17  and presence or absence of the preload member. In the same figure, the configuration described above is referred to as Modification 1-1. 
     As shown in Modification 1-2, the fitting between the second driving side bearing  14  and the first driving side bearing  11  may be a movable loose in the axial direction for both the inner ring and the outer ring. Thereby, the attachment of the bearings  14  and  11  is facilitated and the assembling property improved. 
     In Modification 1-3, the inner ring of the second driving side bearing  14  is set to loose and the outer ring of the second driving side bearing  14  is set to tight, and the inner ring and the outer ring of the first driving side bearing  11  are set to tight. In this way, making the inner ring of the first driving side bearing  11  tight also reduces the misalignment amount around the driving side rotation axis CL 1 . In addition, the first driving side bearing  11  is attached to the same motor housing part  3   a  as the motor  5 , so that it is possible to reliably determine the positional relation with the motor  5 . 
     In Modification 1-4, instead of tightening the inner ring of the first driving side bearing  11  as in Modification 1-3, the inner ring of the rear end bearing  17  is set to tight. Even with such a configuration, it is possible to reduce the misalignment amount around the driving side rotation axis CL 1 . In this case, as shown in  FIG. 9 , a preload member  11   a  pressing the inner ring of the first driving side bearing  11  toward the right side (rear end bearing  17  side) is provided without providing the preload member  17   a  with respect to the rear end bearing  17 . 
     Further, as shown in  FIG. 10 , the preload member  14   a  pressing the inner ring of the second driving side bearing  14  toward the left side (side opposite to the motor  5 ) may be provided. 
     &lt;Modification 2&gt; 
     As shown in  FIG. 12 , in Modification 2, the preload direction of the rear end bearing  17  is different from that in Modification 1 described above, and the other preload directions are the same. 
     On the left side of the rear end bearing  17 , the preload member  17   a  pressing the inner ring of the rear end bearing  17  toward the right side (in the direction opposite to the driving side scroll member  70  side) is provided. The application of a preload to the inner ring of the rear end bearing  17  by the preload member  17   a  causes the load to be applied from the left side of the inner ring to the right side of the outer ring, as shown by the thick solid line in the figure. 
     In addition, the preload member  11   a  pressing the inner ring of the first driving side bearing  11  toward the right side (the rear end bearing  17  side) is provided. 
       FIG. 13  shows a combination of fitting of each of the bearings  11 ,  14  and  17  and presence or absence of the preload member. 
     In Modification 2-1, the inner rings of each of the bearings  11 ,  14  and  17  are set to loose and the outer ring is set to tight. And fixing the preload members  11   a  and  17   a  and the housing  3  causes a preload to be applied to each of the bearings  11 ,  14  and  17 . 
     In Modification 2-2, setting the inner ring of the second driving side bearing  14  to tight reduces the misalignment amount around the driving side rotation axis CL 1 . 
     In Modification 2-3, setting the inner ring of the first driving side bearing  11  to tight reduces the misalignment amount around the driving side rotation axis CL 1 . 
     In Modification 2-4, setting all the inner rings and outer rings of each of the bearings  11 ,  14  and  17  to loose facilitates the attachment of each of the bearings  11 ,  14 , and  17 , thereby improving assembling property. 
     For each of Modifications 2-1 to 2-4, the preload member  14   a  pressing the inner ring of the second driving side bearing  14  toward the left side (side opposite to the motor  5 ) may be provided as shown in  FIG. 10 . 
     &lt;Modification 3&gt; 
     As shown in  FIG. 14 , in Modification 3, the preload directions of the first driving side bearing  11  and the second driving side bearing  14  are different from those of Modification 1 described above, and the preload direction of the rear end bearing  17  is the same. 
     In Modification 3-1, the preload members  11   a ,  14   a  and  17   a  are provided for each of the bearings  11 ,  14 , and  17 . 
     On the left side of the second driving side bearing  14 , the preload member  14   a  pressing the inner ring of the second driving side bearing  14  to the right side (direction toward the driving side scroll member  70  side) is provided. The application of a preload to the inner ring of the second driving side bearing  14  by the preload member  14   a  causes the load to be applied from the left side of the inner ring toward the right side of the outer ring, as shown by the thick solid line in the figure. 
     On the right side of the first driving side bearing  11 , the preload member  11   a  pressing the inner ring of the first driving side bearing  11  toward the left side (the direction toward the driving side scroll member  70  side) is provided. The application of a preload to the inner ring of the first driving side bearing  11  by the preload member  11   a  causes the load to be applied from the right side of the inner ring to the left side of the outer ring, as shown by the thick solid line in the figure. 
     On the right side of the rear end bearing  17 , the preload member  17   a  pressing the inner ring of the rear end bearing  17  toward the left side (direction toward the driving side scroll member  70  side) is provided. The application of a preload to the inner ring of the rear end bearing  17  by the preload member  17   a  causes the load to be applied from the right side of the inner ring to the left side of the outer ring, as shown by the thick solid line in the figure. 
       FIG. 15  shows a combination of fitting of each of the bearings  11 ,  14  and  17  and presence or absence of the preload member. 
     In Modification 3-2, the preload member  14   a  of the second driving side bearing  14  of Modification 3-1 described above is omitted, and the inner ring of the second driving side bearing  14  is set to tight. As a result, the number of parts is reduced, and the misalignment amount around the driving side rotation axis CL 1  is reduced. 
     In Modification 3-3, the preload member  11   a  of the first driving side bearing  11  of Modification 3-1 described above is omitted, and the inner ring of the first driving side bearing  11  is set to tight. As a result, the number of parts is reduced, and the misalignment amount around the driving side rotation axis CL 1  is reduced. 
     In Modification 3-4, the preload member  17   a  of the rear end bearing  17  of Modification 3-1 described above is omitted, and the inner ring of the rear end bearing  17  is set to tight. As a result, the number of parts is reduced, and the misalignment amount around the driving side rotation axis CL 1  is reduced. 
     &lt;Modification 4&gt; 
     As shown in  FIG. 16 , in Modification 4, the preload direction of the rear end bearing  17  is different from that of Modification 3 described above, and the other preload directions are the same. 
     In Modification 4-1, on the left side of the rear end bearing  17 , the preload member  17   a  pressing the inner ring of the rear end bearing  17  toward the right side (in the direction opposite to the driving side scroll member  70  side) is provided. The application of a preload to the inner ring of the rear end bearing  17  by the preload member  17   a  causes the load to be applied from the left side of the inner ring to the right side of the outer ring, as shown by the thick solid line in the figure. 
       FIG. 17  shows a combination of fitting of each of the bearings  11 ,  14  and  17  and presence or absence of the preload member. 
     In Modification 4-2, the preload member  14   a  of the second driving side bearing  14  of Modification 4-1 described above is omitted, and the inner ring of the second driving side bearing  14  is set to tight. As a result, the number of parts is reduced, and the misalignment amount around the driving side rotation axis CL 1  is reduced. 
     In Modification 4-3, the preload member  11   a  of the first driving side bearing  11  of Modification 4-1 described above is omitted, and the inner ring of the first driving side bearing  11  is set to tight. As a result, the number of parts is reduced, and the misalignment amount around the driving side rotation axis CL 1  is reduced. 
     In Modification 4-4, the preload member  17   a  of the rear end bearing  17  of Modification 4-1 described above is omitted, and the inner ring of the rear end bearing  17  is set to tight. As a result, the number of parts is reduced, and the misalignment amount around the driving side rotation axis CL 1  is reduced. 
     &lt;Modification 5&gt; 
       FIG. 18  shows a modification of how a preload is applied to the support member bearings  37  and  38  on the driven side, for the first embodiment. 
     In the second support member bearing  38 , the inner ring is loosely fitted to be fixed to be movable in the axial direction with respect to the second support member shaft part  35   a , and the outer ring is tightly fitted to be fixed not to move in the axial direction with respect to the housing  3 . On the left side of the second support member bearing  38 , a preload member  38   a  pressing the inner ring of the second support member bearing  38  toward the driven side scroll member  90  side is provided. The preload member  38   a  is a nut or the like, and is screwed to the second support member shaft part  35   a . The application of a preload to the inner ring of the second support member bearing  38  by the preload member  38   a  causes the load to be applied from the left side of the inner ring to the right side of the outer ring, as shown by the thick solid line in the figure. 
     In the first support member bearing  37 , the inner ring is loosely fitted to be fixed to be movable in the axial direction with respect to the first support member shaft part  33   a , and the outer ring is tightly fitted to be fixed not to move in the axial direction with respect to the housing  3 . On the right side of the first support member bearing  37 , the preload member  37   a  pressing the inner ring of the first support member bearing  37  toward the driven side scroll member  90  side is provided. The preload member  37   a  is a nut or the like, and is screwed to the first support member shaft part  33   a . The application of a preload to the inner ring of the first support member bearing  37  by the preload member  37   a  causes the load to be applied from the right side of the inner ring to the left side of the outer ring, as shown by the thick solid line in the figure. 
     According to such a configuration, similarly to the deformation shown in  FIG. 5( b ) , the suppression of the deformation in which a distance to axial direction between both the shaft parts  33   a  and  35   a  supported by each of the bearings  37  and  38  decreases, can alleviate the stress generated in the driven side scroll member  90 , further suppress the leakage of the compressed air generated by the deformation of the driven side scroll member  90 . 
     Further, for example, similarly to the deformation shown in  FIG. 6( b ) , the distance between both the shaft parts  33   a  and  35   a  supported by each of the bearings  37  and  38  can be increased according to the thermal expansion, so that the generation of the thermal stress can be suppressed. 
     In  FIG. 19 , a combination of fitting of each of the bearings  37  and  38  and presence or absence of the preload member is shown. In the same figure, the above-described configuration is Modification 5-1. 
     In Modification 5-2, the inner ring of the second support member bearing  38  is set to tight with respect to Modification 5-1. Thereby, it is possible to reduce the misalignment amount around the driven side rotation axis CL 2 . In this case, the preload member  38   a  of the second support member bearing  38  can be omitted, and the number of parts can be reduced. 
     In Modification 5-3, the inner ring of the first support member bearing  37  is set to tight with respect to Modification 5-1. Thereby, it is possible to reduce the misalignment amount around the driven side rotation axis CL 2 . In this case, a preload member  37   a  of the first support member bearing  37  can be omitted, and the number of parts can be reduced. 
     &lt;Modification 6&gt; 
     As shown in  FIG. 20 , in Modification 6, the preload directions of each of the bearings  37  and  38  are different from those of Modification 5 described above. 
     On the right side of the second support member bearing  38 , the preload member  38   a  pressing the inner ring of the second support member bearing  38  toward the left side (opposite direction to the driven side scroll member  90  side) is provided. The application of a preload to the inner ring of the second support member bearing  38  by the preload member  38   a  causes the load to be applied from the right side of the inner ring to the left side of the outer ring, as shown by the thick solid line in the figure. 
     On the left side of the first support member bearing  37 , the preload member  37   a  pressing the inner ring of the first support member bearing  37  toward the right side (opposite direction to the driven side scroll member  90  side) is provided. The application of a preload to the inner ring of the first support member bearing  37  by the preload member  37   a  causes the load to be applied from the left side of the inner ring to the right side of the outer ring, as shown by the thick solid line in the figure. 
     A preload is applied to each of the bearing  37  and  38  when the motor housing part  3   a  and the scroll housing part  3   b  of the housing  3  are contacted to be fixed by the bolts  32  in the axial direction, it is possible to omit the preload members  37   a  and  38   a.    
     In  FIG. 21 , the fitting combination of each of the bearings  37  and  38  is shown. The preload members  37   a  and  38   a  can be omitted if a preload is applied when the motor housing part  3   a  and the scroll housing part  3   b  of the housing  3  are contacted to be fixed by the bolts  32  in the axial direction. 
     In Modification 6-1, the inner ring of each of the bearings  37  and  38  is set to be loose and the outer ring is set to tight. 
     In Modification 6-2, the outer rings of both the bearings  37  and  38  are set to loose with respect to Modification 6-1. Thereby, the attachment of each of the bearings  37  and  38  is facilitated and the assembling property improved. 
     In Modification 6-3, the inner ring of the second support member bearing  38  is set to tight with respect to Modification 6-1. Thereby, it is possible to reduce the misalignment amount around the driven side rotation axis CL 2 . 
     In Modification 6-4, the inner ring of the first support member bearing  37  is set to tight with respect to Modification 6-1. Thereby, it is possible to reduce the misalignment amount around the driven side rotation axis CL 2 . 
     &lt;Modification 7&gt; 
     As shown in  FIG. 22 , Modification 7 is different from the above Modification 5 in that the preload members  37   a  and  38   a  are omitted, and the preload direction is the same. In addition, this modification is different from Modification 5 in that the shaft part  33   a  of the first support member  33  is fitted to the outer ring of the first support member bearing  37 , and the housing  3  is fitted to the inner ring of the first support member bearing  37 . Similarly, this modification is different from Modification 5 in that the shaft part  35   a  of the second support member  35  is fitted to the outer ring of the second support member bearing  38 , and the inner ring of the second support member bearing  38  is fitted to the housing  3 . 
     A preload is applied to each of the bearing  37  and  38  when the motor housing part  3   a  and the scroll housing part  3   b  of the housing  3  are contacted to be fixed by the bolts  32  in the axial direction. 
     In  FIG. 23 , a combination of fitting of each of the bearings  37  and  38  is shown. 
     In Modification 7-1, the inner ring of each of the bearings  37  and  38  is set to loose and the outer ring is set to tight. 
     In Modification 7-2, the outer rings of both the bearings  37  and  38  are set to loose with respect to Modification 7-1. Thereby, the attachment of each of the bearings  37  and  38  is facilitated and the assembling property is improved. 
     In Modification 7-3, the inner ring of the second support member bearing  38  is set to tight with respect to Modification 7-1. Thereby, it is possible to reduce the misalignment amount around the driven side rotation axis CL 2 . 
     In Modification 7-4, the inner ring of the first support member bearing  37  is set to tight with respect to Modification 7-1. Thereby, it is possible to reduce the misalignment amount around the driven side rotation axis CL 2 . 
     &lt;Modification 8&gt; 
     As shown in  FIG. 24 , the first driving side bearing  11  may be omitted, and the second driving side bearing  14  and the rear end bearing  17  may support the rotation around the driving side rotation axis CL 1 . As a result, the number of parts can be reduced. In addition, as for a preload, as shown in  FIG. 24 , applying a preload by the rear end bearing  17  instead of the first driving side bearing  11  can obtain the same effect as in the first embodiment. 
     In each of the above-described embodiments and modifications, the co-rotating scroll compressor is used as a supercharger, but the present invention is not limited to this, and it can be widely used as long as it compresses a fluid, and it can also be used as a refrigerant compressor used in, for example, an air conditioner. 
     REFERENCE SIGNS LIST 
     
         
           1 A,  1 B,  1 C Co-rotating scroll compressor 
           3  Housing 
           3   a  Motor housing part (first housing) 
           3   b  Scroll housing part (second housing) 
           3   c  Cooling fin 
           3   d  Discharge port 
           5  Motor (drive part) 
           5   a  Stator 
           5   b  Rotor 
           6  Drive shaft 
           7  Driving side scroll member 
           7   a  Driving side end plate 
           7   b  Driving side wall body 
           7   c  First driving side shaft part (driving side shaft part) 
           9  Driven side scroll member 
           9   a  Driven side end plate 
           9   b  Driven side wall part 
           9   c  Driven side shaft part 
           11  First driving side bearing 
           11  Preload member 
           14  Second driving side bearing 
           14   a  Preload member 
           13  Driven side bearing 
           15  Pin ring mechanism (synchronous driving mechanism) 
           15   a  Ring member 
           15   b  Pin member 
           17  Rear end bearing 
           17   a  Preload member 
           20  Driving side support member 
           20   a  Driving side support member shaft part 
           22  Driven side support member 
           22   a  Driven side support member shaft part 
           24   a  Pin 
           24   b  Pin 
           25   a  Pin 
           25   b  Pin 
           26  Driving side support member bearing 
           28  Driven side support member bearing 
           31  Pin (fixed portion of wall) 
           32  Bolt 
           33  First support member 
           33   a  First support member shaft part 
           35  Second support member 
           35   a  Second support member shaft part 
           37  First support member bearing (first driven side bearing) 
           38  Second support member bearing (second driven side bearing) 
           70  Driving side scroll member 
           71  First driving side scroll part 
           71   a  First driving side end plate 
           71   b  First driving side wall body 
           72  Second driving side scroll part 
           72   a  Second driving side end plate 
           72   b  Second driving side wall body 
           72   c  Second driving side shaft part 
           72   d  Discharge port 
           73  Flange part 
           90  Driven side scroll member 
           90   a  Driven side end plate 
           90   h  Through hole 
           91   b  First driven side wall body 
           92   b  Second driven side wall body 
         CL 1  Driving side rotation axis 
         CL 2  Driven side rotation axis 
         P Dividing face