JP4935360B2 - Power transmission device - Google Patents

Description

  The present invention relates to a power transmission device. In particular, the present invention relates to a torque converter mounted on an automobile.

  The power transmission device is a device for transmitting power from one device to another device. Examples of the power transmission device include an automobile torque converter. A torque converter is a device attached between a drive device such as an engine or a motor and a transmission. The torque converter has a function of transmitting power from the drive device to the transmission.

  Japanese Patent Application Laid-Open No. 2004-132526 discloses a support device that supports a stator of a torque converter. In this support device, an end bearing that holds a gap between the outer race disposed on the inner periphery of the stator and the inner race disposed on the outer periphery of the rotating shaft of the torque converter, and the end race is disposed adjacent to the end race. And a thrust bearing race that restricts the end bearing from moving in the direction of the transmission rotating shaft, and a thrust bearing that is disposed on a transfer surface of the thrust bearing race and supports a load acting on the outer race. Has been.

In Japanese Utility Model Publication No. 63-80361, in a lock-up type torque converter, a thrust receiving portion between a turbine runner and a one-way clutch is constituted by a thrust washer, and a sliding contact portion between the thrust washer and the turbine runner and the one-way clutch is provided. A thrust bearing device for a lockup type torque converter having a lubrication path for guiding a working fluid in a lockup control chamber is disclosed.
JP 2004-132526 A Japanese Utility Model Publication No. 63-80361

  In a power transmission device such as a torque converter, a pump impeller and a turbine runner are disposed so as to face each other, and a working fluid is disposed between the pump impeller and the turbine runner. The driving force of the driving device is input to the pump impeller. When the pump impeller rotates, the working fluid flows toward the turbine runner, and the turbine runner rotates. The turbine runner is connected to the output shaft of the power transmission device. As the turbine runner rotates, the output shaft rotates.

  A stator is disposed between the pump impeller and the turbine runner. The stator is fixed to the fixed shaft via a one-way clutch, for example. The one-way clutch is disposed between a pump impeller support member that supports the pump impeller and a turbine runner support member that supports the turbine runner. For this reason, thrust bearings are disposed between the one-way clutch and the pump impeller and between the one-way clutch and the turbine runner.

  Japanese Utility Model Laid-Open No. 63-80361 discloses disposing a thrust washer between a turbine runner support member for supporting a turbine runner and a one-way clutch, and supplying a working fluid to the thrust washer. Has been. However, even in this structure, there is a problem that resistance is generated as a result of a load applied to the surfaces on both sides of the thrust washer. That is, there is a problem that the performance of the torque converter is lowered because sliding resistance is generated.

  An object of this invention is to provide the power transmission device with small resistance when driving.

The power transmission device in one aspect based on this invention is provided with the pump impeller for inputting the driving force of a drive device, and the turbine runner arrange | positioned so as to oppose the said pump impeller. An output shaft for outputting a driving force is provided. A stator disposed between the pump impeller and the turbine runner; A stator support member for supporting the stator is provided. A turbine runner support member for supporting the turbine runner is provided. The output shaft has a first engagement portion that engages with the turbine runner support member. The first engaging portion has a convex portion formed so as to be fitted to the turbine runner support member. The first engaging portion is formed such that a direction in which the convex portion extends is inclined with respect to a rotation axis of the output shaft when the output shaft is viewed from the side. The direction in which the convex portion inclines is formed such that when the driving force of the driving device is input, the force acts in a direction in which the turbine runner support member is separated from the stator support member. A first washer is provided between the turbine runner support member and the stator support member. A distance between the turbine runner support member and the stator support member is determined by the first washer.

The power transmission device in another aspect based on this invention is provided with the pump impeller for inputting the driving force of a drive device, and the turbine runner arrange | positioned so as to oppose the said pump impeller. A stator disposed between the pump impeller and the turbine runner; A stator support member for supporting the stator is provided. A pump impeller support member for supporting the pump impeller is provided. A fixed shaft for supporting the stator support member is provided. The fixed shaft has a second engagement portion that engages with the stator support member. The second engaging portion has a convex portion formed so as to be fitted to the stator support member. The second engaging portion is formed such that a direction in which the convex portion extends is inclined with respect to the rotation axis of the stator when the fixed shaft is viewed from the side. The direction in which the convex portion inclines is formed such that when the driving force of the driving device is input, the force acts in a direction in which the stator support member is separated from the pump impeller support member. A second washer is provided between the pump impeller support member and the stator support member. The distance between the pump impeller support member and the stator support member is determined by the second washer.

  ADVANTAGE OF THE INVENTION According to this invention, a power transmission device with small resistance when driving can be provided.

(Embodiment 1)
The power transmission device in the first embodiment will be described with reference to FIGS. 1 to 5. The power transmission device in the present embodiment is a torque converter mounted on an automobile. The torque converter has a function of transmitting a driving force of a driving device such as an engine to a transmission or the like.

  FIG. 1 is a schematic cross-sectional view of the torque converter in the present embodiment. The engine is arranged on the left side of the page of FIG. 1, and the transmission is arranged on the right side of the page of FIG.

  The torque converter 1 transmits torque from the crankshaft of the engine to the input shaft 6 of the transmission. In the present embodiment, the output shaft for outputting the driving force of the torque converter is the input shaft of the transmission.

  In the present embodiment, the rotation shaft of the input shaft 6 of the transmission is the rotation shaft 80 of the torque converter 1. In the present embodiment, when the rotational force of the engine is input to the front cover 3, the front cover 3 rotates in the direction indicated by the arrow 90. The rotational force of the front cover 3 is transmitted, and the input shaft 6 of the transmission rotates in the direction indicated by the arrow 91.

  The torque converter 1 includes a turbine runner 40 and a pump impeller 30 as three impellers. The torque converter 1 includes a stator 23. The torque converter 1 includes a lockup mechanism 70.

  A disc-shaped front cover 3 is disposed on the engine side of the torque converter 1. The front cover 3 is formed to extend outward from the rotating shaft, that is, to extend in the radial direction. The front cover 3 functions as a front case of the torque converter 1.

  A pump shell 33 is fixed to the front cover 3. A predetermined space is formed by the front cover 3 and the pump shell 33. Various elements of the torque converter 1 are arranged in this space. The space surrounded by the front cover 3 and the pump shell 33 is a substantially sealed space. In this space, automatic transmission fluid (ATF) as a working fluid is enclosed.

  The pump impeller 30 includes a pump shell 33. The pump shell 33 is a component member outside the pump impeller 30. When power is input from the engine to the front cover 3, the front cover 3 rotates and this rotational force is transmitted to the pump shell 33.

  The pump impeller 30 can rotate around the rotation shaft 80. The pump impeller 30 has a blade 31 shaped to push the working fluid toward the turbine runner 40. As the pump impeller 30 rotates, the working fluid in the vicinity of the pump impeller 30 is pushed out toward the turbine runner 40 by the blade 31. The pump impeller 30 is supported by a pump impeller support member 34.

  The stator 23 is a blade for rectifying the flow of the working fluid returning from the turbine runner 40 to the pump impeller 30. The stator 23 is made of resin or aluminum alloy. The stator 23 is disposed between the pump impeller 30 and the turbine runner 40. The stator 23 functions to change the flow direction of the working fluid flowing from the turbine runner 40 to the pump impeller 30.

  The torque converter 1 in the present embodiment includes a one-way clutch 51 as a stator support member for supporting the stator 23. The stator 23 is attached to the fixed shaft 39 via a one-way clutch 51. The fixed shaft 39 is fixed without rotating. The one-way clutch 51 is formed so that the stator 23 rotates only in one direction. As the one-way clutch 51, a structure using a roller, a sprag, a ratchet, or the like can be adopted. One-way clutch 51 in the present embodiment includes sprags 56.

  The turbine runner 40 includes a turbine shell 43 that forms a space for circulating a working fluid. The turbine runner 40 is disposed so as to face the pump impeller 30. The turbine runner 40 includes a blade 41 having a shape that rotates in response to the working fluid from the pump impeller 30. The turbine runner 40 receives the working fluid sent out by the pump impeller 30 as indicated by an arrow 92, and a rotational force is applied by the working fluid. The working fluid sent to the turbine runner 40 moves to the inner peripheral side and is sent to the pump impeller 30 via the stator 23. The turbine runner 40 can rotate independently of the pump impeller 30.

  The pump impeller 30 rotates integrally with the front cover 3, while the turbine runner 40 rotates integrally with the lockup piston 4. A transmission member 77 is arranged so as to come into contact with the turbine shell 43. The transmission member 77 is integrated with the turbine shell 43 with fasteners such as rivets or bolts. The transmission member 77 rotates together with the turbine shell 43.

  The turbine runner 40 is supported by a turbine hub 7 as a turbine runner support member. Both the transmission member 77 and the turbine shell 43 are fixed to the turbine hub 7. The transmission member 77 and the turbine shell 43 can rotate with the turbine hub 7 about the input shaft 6 as a rotation axis.

  The turbine hub 7 is fitted to the input shaft 6 by a spline. The turbine hub 7 is disposed on the outer peripheral surface of the input shaft 6. The turbine hub 7 connects the input shaft 6 and the turbine runner 40. The turbine hub 7 serves to transmit the rotational force input to the turbine runner 40 to the input shaft 6.

  When the torque amplifying action of the torque converter is required, the turbine runner 40 is rotated by the flowing working fluid as indicated by an arrow 92. The rotational force of the turbine runner 40 is transmitted to the input shaft 6 via the turbine hub 7.

  Next, the lockup mechanism 70 will be described. The lockup mechanism 70 is a device for directly transmitting the rotational force of the front cover 3 to the input shaft 6. The lock-up mechanism 70 includes a facing 76 as a friction member. When the facing 76 contacts the inner peripheral surface of the front cover 3, the rotational force of the front cover 3 is transmitted to the input shaft 6. The lockup mechanism 70 has a lockup piston 4 for attaching a facing 76.

  The lockup piston 4 is formed so as to be movable in the axial direction of the input shaft 6. The lockup piston 4 enables the facing 76 to abut against the front cover 3. The lock-up piston 4 is formed in a disk shape extending in the radial direction (radial direction) of rotation. The lockup piston 4 is disposed so as to face the front cover 3. The facing 76 is disposed on the outer peripheral side of the lockup piston 4. The lockup piston 4 is fixed to the turbine hub 7.

  In the present embodiment, the space between the front cover 3 and the lockup piston 4 is the first hydraulic chamber 10a. A space between the lockup piston 4 and the transmission member 77 is the second hydraulic chamber 10b. The first and second hydraulic chambers 10a and 10b are filled with working fluid. By changing the oil pressure in the first and second hydraulic chambers 10a and 10b, the lockup piston 4 can be moved in a direction approaching the front cover 3 and a direction away from the front cover 3.

  The lockup mechanism 70 is provided with a lockup damper 74. The lockup damper 74 plays a role of mitigating input fluctuations. The lockup damper 74 includes a spring member. The lock-up damper 74 has a function of reducing fluctuations by the action of a spring member when torque is applied. The lockup damper 74 is disposed between the lockup piston 4 and the transmission member 77.

  The operation of the lock-up mechanism 70 will be described. When the torque amplifying action of the torque converter 1 is not necessary, the rotational force of the front cover 3 is directly transmitted to the input shaft 6 by bringing the facing 76 into direct contact with the front cover 3. Specifically, the working fluid in the first hydraulic chamber 10 a is discharged through a through hole 6 h formed in the input shaft 6. As a result, the hydraulic pressure in the first hydraulic chamber 10a is lower than the hydraulic pressure in the second hydraulic chamber 10b. As a result, the lockup piston 4 moves in a direction approaching the front cover 3. The facing 76 contacts the front cover 3. As a result, the power of the front cover 3 is transmitted to the input shaft 6 via the facing 76, the lockup piston 4 and the turbine hub 7. In this state, power loss due to the torque converter 1 can be avoided.

  When the torque amplification action of the torque converter 1 is required, the working fluid is sent into the first hydraulic chamber 10a through the through hole 6h. Thereby, the pressure in the first hydraulic chamber 10a increases. The lockup piston 4 is pushed back in a direction away from the front cover 3. A gap is generated between the front cover 3 and the facing 76. In this state, it can be avoided that the rotational force of the front cover 3 is directly transmitted to the facing 76.

  The stator 23 is supported on the fixed shaft 39 via the one-way clutch 51. The one-way clutch 51 is disposed on the inner peripheral surface of the stator 23. One-way clutch 51 in the present embodiment includes an outer race 52, an inner race 55, and a sprag 56.

  A plurality of sprags 56 are disposed between the outer race 52 and the inner race 55. Further, an end bearing 54 is disposed between the outer race 52 and the inner race 55. The end bearing 54 keeps the distance between the outer race 52 and the inner race 55 constant. Further, the end bearing 54 restricts the movement of the sprag 56. A thrust bearing race 53 is disposed adjacent to both end faces of the outer race 52. The thrust bearing race 53 regulates the movement of the end bearing 54 and the inner race 55.

  A thrust bearing 61 is disposed on the side surface of the one-way clutch 51 on the transmission side. The thrust bearing 61 is an interposed member between the one-way clutch 51 and the pump impeller support member 34, and determines the distance between the one-way clutch 51 and the pump impeller support member 34. The surface of the thrust bearing race 53 is subjected to surface processing or surface treatment so that rolling elements (rollers, balls, etc.) of the bearing roll smoothly. The thrust bearing 61 is disposed adjacent to the thrust bearing race 53.

  In the present embodiment, a washer 62 as a first washer is disposed on the engine side surface of the one-way clutch 51. A washer 62 is arranged between the turbine hub 7 and the one-way clutch 51 as an interposed member that determines the distance between the turbine hub 7 and the one-way clutch 51.

  In FIG. 2, the schematic perspective view of the front-end | tip of the input shaft in this Embodiment is shown. The input shaft 6 is formed in a cylindrical shape. A spline portion 6 a as a first engaging portion is formed at the tip of the input shaft 6. The spline portion 6a has a plurality of convex portions. The spline portion 6a is formed so as to be splined with the turbine hub 7.

  On the fitting surface of the turbine hub 7, a spline part is formed so as to be fitted with the spline part 6 a of the input shaft 6. The spline portion 6a in the present embodiment is formed to have a twist angle.

  In FIG. 3, the side view of the front-end | tip of the input shaft in this Embodiment is shown. Referring to FIGS. 1 and 3, spline portion 6 a is formed so that the extending direction of the convex portion is inclined with respect to the rotation axis of input shaft 6 when viewed from the side.

  Referring to FIGS. 1 to 3, spline portion 6 a is formed such that a force acts in a direction in which turbine hub 7 indicated by arrow 93 moves away from one-way clutch 51 when engine driving force is input. ing. For example, when the engine speed is increasing or when the engine speed is constant, a force acts on the turbine hub 7 in a direction away from the one-way clutch 51.

  When engine driving force is input, the working fluid flows in the direction indicated by the arrow 92. At this time, a force acts on the turbine runner 40 in a direction approaching the pump impeller 30. That is, the turbine runner 40 tends to move in the direction indicated by the arrow 94. Thus, the force in the direction along the rotation axis of the input shaft 6 acts on the turbine runner 40. However, in the present embodiment, since the input shaft 6 and the turbine hub 7 are fitted by a spline having an inclined convex portion, the force acts in a direction to cancel this force. That is, a force acts in the direction indicated by the arrow 93.

  For this reason, it can suppress that force is added to the interposition member for determining the distance between the one-way clutch 51 and the turbine hub 7. As a result, the sliding resistance between the one-way clutch 51 and the interposed member, or between the turbine hub 7 and the interposed member can be reduced, and the performance of the torque converter can be improved.

  Further, it is not necessary to use a thrust bearing as the interposed member disposed between the one-way clutch 51 and the turbine hub 7, and the washer 62 can be disposed. Even if a washer is used as the interposition member, the sliding resistance can be reduced. Moreover, wear of the washer can be suppressed. As described above, the torque converter according to the present embodiment does not need to use an expensive thrust bearing having a complicated structure, and can simplify the configuration.

  Even when a thrust bearing is disposed as an interposed member between the one-way clutch 51 and the turbine hub 7, the load applied to the thrust bearing can be reduced, and the resistance during rotation can be further reduced. .

  Next, the twist angle of the convex part of the spline part in this Embodiment is demonstrated. Referring to FIG. 3, the convex portion of spline portion 6a in the present embodiment extends at twist angle θ.

  FIG. 4 is a graph showing the relationship between turbine torque and thrust load applied in the thrust direction. The horizontal axis represents the turbine torque, and the vertical axis represents the thrust load acting in the axial direction. As shown in FIG. 4, the turbine torque and the thrust load have a proportional relationship.

  Here, when the turbine torque is Tt, the axial thrust load F is given by the following equation (1).

F = a × Tt (1)
Here, a is a proportionality constant.

  FIG. 5 shows a schematic cross-sectional view of the spline portion of the input shaft. The length indicated by the arrow 95 is a line connecting the midpoints of the convex portions of the spline portion 6a. The size of this diameter is called PCD (pitch circle diameter). When the PCD of the spline portion 6a is D, the upper limit of the twist angle θ is expressed by the following equation.

tan θ = F / (Tt (D / 2)) (2)
The spline portion has an effect of reducing the thrust load even at an angle equal to or smaller than the twist angle θ represented by the above formula (2). By forming the spline portion having the torsion angle θ, it is possible to cancel the thrust load at each turbine torque. As a result, the thrust load applied to the washer arranged between the one-way clutch and the turbine hub can be minimized. As a result, for example, the wear of the washer can be further suppressed, and the performance deterioration of the torque converter can be further suppressed.

  In the present embodiment, a thrust bearing 63 is disposed between the front cover 3 and the turbine hub 7. When engine driving force is not input, force is applied to the turbine hub 7 in the direction indicated by the arrow 93. That is, a force toward the front cover 3 acts on the turbine hub 7. However, in this embodiment, since the input shaft 6 and the turbine hub 7 are fitted by a spline having a torsion angle, when no engine driving force is input, the turbine hub is oriented in the direction indicated by the arrow 94. A force acts on 7. For this reason, it is possible to suppress the turbine hub 7 from approaching the front cover 3. As a result, the thrust bearing 63 can be eliminated. Alternatively, the thrust bearing 63 can be replaced with a washer.

  In the present embodiment, the torque converter connected to the transmission of the automobile has been described as an example of the power transmission device. However, the present invention is not limited to this embodiment, and the present invention is applied to any power transmission device. Can do.

(Embodiment 2)
With reference to FIG. 6 and FIG. 7, the power transmission device in the present embodiment will be described. The power transmission device in the present embodiment is a torque converter mounted on an automobile.

  FIG. 6 is a schematic cross-sectional view of the torque converter in the present embodiment. In the torque converter 2 according to the present embodiment, a one-way clutch 51 as a stator support member and a fixed shaft 39 are fitted by a spline.

  The fixed shaft 39 has a spline portion 39a as a second engagement portion formed so as to be spline-fitted with the one-way clutch 51. The axis of the fixed shaft 39 in the present embodiment is the same as the rotating shaft 80 of the torque converter 2.

  A spline portion is formed on the inner surface of the one-way clutch 51 so as to be fitted to the spline portion 39 a of the fixed shaft 39. In the present embodiment, a spline portion is formed on the inner surface of the inner race 55.

  In the present embodiment, a thrust bearing 65 that is an interposed member is disposed between the one-way clutch 51 and the turbine hub 7. Between the one-way clutch 51 and the pump impeller support member 34, a washer 64 as a second washer that is an interposed member is disposed.

  In FIG. 7, the schematic perspective view of the front-end | tip of the fixed shaft 39 in this Embodiment is shown. The fixed shaft 39 in the present embodiment is formed in a cylindrical shape. The spline portion 39 a is formed so as to extend along the axial direction of the fixed shaft 39. The spline portion 39a has a plurality of convex portions.

  6 and 7, the plurality of convex portions of the spline portion 39a are formed such that the extending direction is inclined with respect to the axial direction of the fixed shaft when the fixed shaft 39 is viewed from the side. Yes. The spline portion 39a is formed such that a force is applied in a direction in which the one-way clutch 51 is separated from the pump impeller support member 34 when an engine driving force is input. That is, the spline portion 39a is formed such that a force acts on the one-way clutch 51 in the direction indicated by the arrow 93 when the driving force of the engine is input.

  When the driving force of the engine is input, the working fluid flows from the pump impeller 30 toward the turbine runner 40 as indicated by an arrow 92. Due to the action of the one-way clutch 51, the stator 23 does not rotate and is fixed when the rotation speed of the pump impeller 30 is low. On the other hand, when the rotation speed of the pump impeller 30 is high, the stator 23 is in a rotating state that rotates in the same direction as the engine rotates. A force is applied to the stator 23 in the direction indicated by the arrow 94 regardless of whether the stator 23 is fixed or rotated. A force acts on the one-way clutch 51 in a direction toward the pump impeller support member 34.

  However, since the fixed shaft 39 and the one-way clutch 51 are fitted by the spline portion having the inclined convex portion, at least a part of this force and the force due to the spline fitting is offset. For this reason, the force added to the interposition member interposed between the one-way clutch 51 and the pump impeller support member 34 can be reduced. As a result, the sliding resistance on the surface of the interposed member can be reduced, and the performance of the torque converter can be improved. Further, as in the present embodiment, a washer 64 can be disposed as an interposition member between the one-way clutch 51 and the pump impeller support member 34 instead of the thrust bearing.

  In the present embodiment, the thrust bearing is arranged between the one-way clutch and the turbine hub. However, the present invention is not limited to this configuration, and as shown in the first embodiment, the input shaft and the turbine hub are connected to the convex portion. The washer may be disposed between the one-way clutch and the turbine hub by fitting with an inclined spline. Further, the thrust bearing disposed between the front cover and the turbine hub may be eliminated, or a washer may be disposed in place of the thrust bearing.

  Other configurations, operations, and effects are the same as those in the first embodiment, and thus description thereof will not be repeated here.

  In the respective drawings described above, the same or corresponding parts are denoted by the same reference numerals.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic cross-sectional view of a torque converter in a first embodiment. 2 is a schematic perspective view of a tip end of an input shaft in Embodiment 1. FIG. 3 is a schematic side view of a tip end of an input shaft in Embodiment 1. FIG. 4 is a graph for explaining a relationship between turbine torque and thrust load in the first embodiment. It is a schematic sectional drawing explaining PCD of a spline. FIG. 5 is a schematic cross-sectional view of a torque converter in a second embodiment. FIG. 10 is a schematic perspective view of the tip of a fixed shaft in the second embodiment.

Explanation of symbols

  1, 2 Torque converter, 3 Front cover, 4 Lock-up piston, 6 Input shaft, 6a Spline part, 6h Through hole, 7 Turbine hub, 10a First hydraulic chamber, 10b Second hydraulic chamber, 23 Stator, 30 Pump impeller, 31 Blade, 33 Pump shell, 34 Pump impeller support member, 39 Fixed shaft, 39a Spline part, 40 Turbine runner, 41 Blade, 43 Turbine shell, 51 One-way clutch, 52 Outer race, 53 Thrust bearing race, 54 End bearing, 55 Inner Race, 56 sprag, 61, 63, 65 Thrust bearing, 62, 64 washer, 70 Lock-up mechanism, 74 Lock-up damper, 76 facing, 77 Transmission member, 80 rotations Axis, 90-95 arrows.

Claims (2)

A pump impeller for inputting the driving force of the driving device;
A turbine runner arranged to face the pump impeller;
An output shaft for outputting a driving force;
A stator disposed between the pump impeller and the turbine runner;
A stator support member for supporting the stator;
A turbine runner support member for supporting the turbine runner,
The output shaft has a first engagement portion that engages with the turbine runner support member,
The first engaging portion has a convex portion formed so as to be fitted to the turbine runner support member,
The first engaging portion is formed such that a direction in which the convex portion extends is inclined with respect to a rotation axis of the output shaft when the output shaft is viewed from a side.
The direction in which the convex portion inclines is formed such that when the driving force of the driving device is input, the force acts in a direction in which the turbine runner support member is separated from the stator support member,
A first washer disposed between the turbine runner support member and the stator support member;
The power transmission device , wherein a distance between the turbine runner support member and the stator support member is determined by the first washer . A pump impeller for inputting the driving force of the driving device;
A turbine runner arranged to face the pump impeller;
A stator disposed between the pump impeller and the turbine runner;
A stator support member for supporting the stator;
A pump impeller support member for supporting the pump impeller;
A fixed shaft for supporting the stator support member,
The fixed shaft has a second engagement portion that engages with the stator support member;
The second engaging portion has a convex portion formed so as to be fitted to the stator support member,
The second engaging portion is formed so that a direction in which the convex portion extends is inclined with respect to a rotation axis of the stator when the fixed shaft is viewed from a side.
The direction in which the convex portion inclines is formed such that when the driving force of the driving device is input, the force acts in a direction in which the stator support member is separated from the pump impeller support member,
A second washer disposed between the pump impeller support member and the stator support member;
The power transmission device , wherein a distance between the pump impeller support member and the stator support member is determined by the second washer .

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