JP2008032141A - Automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic transmission having a compact speed change mechanism composed of a plurality of planetary gear sets and a plurality of friction tightening elements. <P>SOLUTION: In a configuration of the automatic transmission provided with the planetary gear sets 22 on which a sun gear 22a is fixed, in which rotation is input from an end on one side of a ring gear 22d, and from which rotation is output through a carrier 22c from an end on the other side and a clutch 33 provided at the outer periphery of the planetary gear set 22 and having a clutch drum 110 and a clutch hub 120, the carrier 22c of the planetary gear set 22 and the clutch hub 120 of the clutch 33 are mutually connected on a side of the end on the other side of the planetary gear set 22, and a hydraulic servo device composed of a piston 140 for tightening the clutch 33 on the clutch hub 120 and an oil pressure chamber 160 is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a structure of an automatic transmission, particularly a mechanical power transmission mechanism thereof, and belongs to the technical field of automobiles.

  An automatic transmission for an automobile is a combination of a torque converter and a transmission gear mechanism, and the power transmission path of the transmission gear mechanism is switched by selective operation of frictional engagement elements such as a plurality of clutches and brakes to obtain a predetermined gear stage. Although it is configured to automatically shift, the number of frictional engagement elements and the number of planetary gear sets constituting the transmission gear mechanism tend to increase with an increase in the number of gears. The issue is how to make it compact.

  For example, Patent Document 1 discloses an automatic transmission that includes a planetary gear set in which a sun gear is fixed, a ring gear is an input element, and a carrier is an output element, and a clutch that connects and disconnects the carrier that is the output element and an output member. In this machine, a structure in which a carrier constituting a planetary gear set and a clutch drum constituting a clutch are connected to each other is disclosed, and Patent Document 2 discloses a reduction planetary gear set similar to the automatic transmission disclosed in Patent Document 1. And a clutch, a configuration in which a planetary gear set carrier and a clutch hub constituting the clutch are connected is disclosed. In any automatic transmission, the axial dimension is shortened by arranging the clutch on the outer periphery of the planetary gear set.

JP 2004-36717 A JP 2002-349647 A

  By the way, as described above, when the ring gear of the planetary gear set is an input element and the carrier is an output element, rotation is input to the ring gear from one end side of the planetary gear set, and the rotation output from the carrier is the planetary gear set. It is taken out from the other end side of the set and inputted to the clutch drum or clutch hub of the clutch.

  In that case, in each of the configurations disclosed in Patent Documents 1 and 2, a hydraulic servo device for fastening the clutch and a balance provided on the opposite side of the hydraulic chamber across the piston of the servo device. Chamber is housed in the clutch drum, so that the clutch drum having a large diameter swells greatly on the other end side of the planetary gear set, that is, on the side from which the output is taken out from the carrier. It is an obstacle to downsizing.

  Therefore, an object of the present invention is to further reduce the size of the transmission in the configuration including the planetary gear set and the clutch as described above.

  In order to solve the above problems, the present invention is configured as follows.

  In the first aspect of the present invention, the sun gear is fixed to a boss portion extending in the axial direction at the shaft center portion of the transmission case, rotation is input from one end of the ring gear, and the carrier is input from the other end. A planetary gear set that outputs rotation via the power, a power transmission member that is disposed on the one end side of the planetary gear set and connected to the output member, and is provided on the outer periphery of the planetary gear set. And a clutch having a hydraulic servo device for fastening a friction plate disposed between them, and the planetary gear set carrier and the clutch clutch on the other end side of the planetary gear set. A hub and a clutch drum of the clutch and the power transmission member. Or characterized in that said the member connected to the clutch hub hydraulic servo device is provided.

  According to a second aspect of the present invention, in the automatic transmission according to the first aspect of the present invention, a disk portion having an outer peripheral portion coupled to the clutch hub on the other end side of the planetary gear set, and the disk A sleeve that is rotatably connected to the boss portion and is connected to the inner peripheral portion of the boss portion, and the inner peripheral portion of the piston constituting the hydraulic servo device is slidably fitted on the outer periphery of the sleeve. And a seal plate that is prevented from moving to the other end side is locked to the other end side, and the outer peripheral portion of the seal plate and the intermediate portion in the radial direction of the piston A sliding contact portion between the two is provided, and a hydraulic chamber constituting the hydraulic servo device is formed by the seal plate, the inner peripheral portion of the piston, and the sleeve.

  According to a third aspect of the present invention, in the automatic transmission according to the second aspect of the present invention, a cylindrical portion that extends the clutch hub to the other end side is provided, and the cylindrical portion and the piston A sliding contact portion is provided between the cylindrical portion, the piston, the disc portion, and the sleeve to form a balance chamber.

  Furthermore, the invention according to claim 4 is the automatic transmission according to claim 2 or claim 3, wherein the disk portion and the sleeve are integrated to form the carrier, and the clutch A hub is provided integrally.

  The invention according to claim 5 is the automatic transmission according to any one of claims 1 to 4, further comprising a brake for fixing the clutch drum of the clutch to the transmission case, The brake is provided on the outer periphery of the clutch so as to overlap in the axial direction.

  With the above configuration, according to each invention of the present application, the following effects can be obtained.

  First, according to the first aspect of the present invention, rotation is input to the ring gear from one end side of the planetary gear set to which the sun gear is fixed, and this rotation is decelerated and output from the other end side of the carrier. The rotation is input to a clutch arranged on the outer periphery of the planetary gear set. And when this clutch is fastened, it transmits to an output member via the power transmission member arrange | positioned at the one end side of the said planetary gear set.

  In this case, according to the present invention, a carrier and a clutch hub are connected on the other end side of the planetary gear set, and a hydraulic servo device is provided for fastening the clutch to the clutch hub or a member connected to the clutch hub. Therefore, the space on the other end side of the planetary gear set for installing the hydraulic servo device can be reduced compared with the case where the hydraulic servo device is housed in a clutch drum having a large diameter, and the transmission can be made compact. It is done.

  According to the second aspect of the present invention, a sleeve connected to the clutch hub via a disk portion on the other end side of the planetary gear set, a seal plate locked to the sleeve, and a piston Since the hydraulic chamber is formed by the inner peripheral portion from the radially intermediate portion, the hydraulic chamber can be configured more compactly compared to the case where the hydraulic chamber is provided in a clutch drum having a large diameter. Further downsizing will be achieved.

  According to the third aspect of the present invention, since the balance chamber is formed inside the cylindrical portion obtained by extending the clutch hub to the other end side, the balance chamber is provided in the clutch drum having a large diameter. The structure can be made more compact than the case, and this also makes the transmission more compact.

  Furthermore, according to the invention described in claim 4, since the clutch hub is integrated in addition to the disk portion and the sleeve constituting the carrier, the number of parts and the number of assembly steps can be reduced. Become.

  According to the fifth aspect of the present invention, when a brake for fixing the clutch drum of the clutch to the transmission case is provided, the brake is provided so as to overlap the outer periphery of the clutch in the axial direction. Therefore, the axial dimension of the transmission is shortened as compared with the case where these are provided in the axial direction.

  Embodiments of the present invention will be described below.

  First, the overall mechanical configuration of the automatic transmission 1 according to the present embodiment will be described with reference to FIG. 1. The automatic transmission 1 is applied to a horizontal engine, and the main component is an engine. It has a driven torque converter 10 and a transmission mechanism 20 to which the output rotation of the torque converter 10 is input. The output rotation of the transmission mechanism 20 is input to the differential device 60 via the intermediate transmission mechanism 50. It is like that.

  The torque converter 10 includes a case 11 connected to the engine output shaft 2, a pump 12 fixed in the case 11, and a pump 12 disposed facing the pump 12 via hydraulic oil. A turbine 13 to be driven, a stator 15 interposed between the pump 12 and the turbine 13 and supported by the transmission case 3 via a one-way clutch 14 to increase torque, and the case 11 The lockup clutch 16 is provided between the turbine 13 and directly connects the engine output shaft 2 and the turbine 13 via the case 11. The rotation of the turbine 13 is output to the transmission mechanism 20 via the turbine shaft 17.

  An oil pump 18 that is driven by the engine output shaft 2 via a case 11 of the torque converter 10 is disposed on the opposite side of the torque converter 10 from the engine.

  The transmission mechanism 20 includes a first planetary gear set 21 disposed on the torque converter 10 side, a second planetary gear set 22 disposed on the anti-torque converter 10 side, and third and third planets disposed between them. The first planetary gear sets 23 and 24 are arranged in order from the torque converter 10 side as a plurality of frictional engagement elements such as clutches and brakes for switching the power transmission paths of the planetary gear sets 21 to 24. ~ The third clutches 31 to 33 and the first and second brakes 41 and 42 arranged in order from the torque converter 10 side as well, so that forward 1st to 6th speed and reverse speed can be obtained. Yes.

  Each of the first to fourth planetary gear sets 21 to 24 includes a sun gear 21a to 24a, a plurality of pinions 21b to 24b respectively meshed with the sun gears 21a to 24a, and a carrier that supports the pinions 21b to 24b. 21c to 24c and ring gears 21d to 24d meshed with the pinions 21b to 24b.

  In the first planetary gear set 21, the sun gear 21a is fixed to the transmission case 3, the carrier 21c is connected to the drum side of the first clutch 31, and the ring gear 21d is connected to the turbine shaft 17 and the drum side of the second clutch. Yes.

  In the second planetary gear set 22, the sun gear 22 a is fixed to the transmission case 3, the ring gear 22 d is connected to the turbine shaft 17, and the carrier 22 c is connected to the hub side of the third clutch 33.

  In the third planetary gear set 23, the sun gear 23a is connected to the drum side of the third clutch 33 and the second brake 42, and the carrier 23c is connected to the hub side of the second clutch 32 and the first brake 41, The ring gear 23 d is connected to the carrier 24 c of the fourth planetary gear set 24.

  Further, in the fourth planetary gear set 24, the sun gear 24a is connected to the hub side of the first clutch 31, the ring gear 24d is connected to the carrier 23c of the third planetary gear set 23, and is connected to the first brake 41, and the carrier 24c. Is coupled to the ring gear 23d of the third planetary gear set 23 and coupled to the output gear 25 to the intermediate transmission mechanism 50.

  The rotation of the output gear 25 is input to the differential device 60 via the intermediate transmission mechanism 50 and drives the left and right axles 61 and 62.

  Here, the relationship between the operating states of the clutches 31 to 33 and the brakes 41 and 42 and the shift speed is shown in Table 1.

Next, the configuration of the second planetary gear set 22 and the third clutch 33 disposed at the end of the transmission gear mechanism 20 on the side opposite to the engine, which is a characteristic part of the present invention, and the periphery thereof will be described in detail.

  As shown in FIG. 2, the opening of the transmission case 3 on the side opposite to the engine (hereinafter referred to as “rear side”) is closed by an end cover 4 that constitutes the transmission case together with the case 3. The shaft center portion is provided with a boss portion 4a extending along the axis toward the engine side (hereinafter referred to as “front side”), and a sleeve member 5 for forming an oil passage is fitted to the base portion of the boss portion 4a. Is fixed. A sun gear 22a of the second planetary gear set 22 is splined and fixed to the front end of the boss portion 4a.

  A disc-shaped first connecting member 22e extending to the inner peripheral side is joined to the front end side of the ring gear 22d of the second planetary gear set 22, and a second connecting member 22f is connected to the inner peripheral portion of the first connecting member 22e. Are joined, and the inner peripheral portion of the second connecting member 22f is spline-fitted to the turbine shaft 17, whereby the rotation of the turbine shaft 17 is input to the ring gear 22d.

  Further, a sleeve 22c ″ extending rearward is integrally formed on the inner peripheral portion of the disc portion 22c ′ on the rear side of the carrier 22c that supports the pinion 22b of the second planetary gear set 22, and this sleeve 22c ″. Is rotatably fitted on the sleeve member 5, whereby the carrier 22c is rotatably supported.

  Thereby, the rotation input from the turbine shaft 17 to the ring gear 22d is decelerated by the second planetary gear set 22 and output from the carrier 22c.

  The third clutch 33 is disposed on the outer periphery of the ring gear 22d of the second planetary gear set 20.

  The third clutch 33 includes a bottomed cylindrical clutch drum 110 that is open at one end, and a cylindrical clutch hub 120 that is disposed inside the drum 110 so as to be relatively rotatable concentrically with the drum 110. And have. The inner peripheral surface of the outer peripheral portion of the drum 110 and the outer peripheral surface of the hub 120 facing the drum 110 are respectively formed with splines of internal teeth and external teeth, and a plurality of frictional teeth having teeth on the outer peripheral side are formed on these splines. The plates 131... 131 and the plurality of friction plates 132... 132 having teeth on the inner peripheral side are alternately engaged.

  The clutch hub 120 of the third clutch 33 is connected to the outer periphery of the disc portion 22c ′ of the carrier 22c constituting the second planetary gear set 22, and is formed integrally with the disc portion 22c ′. The hub 120 is provided with an extended cylindrical portion 121 extending rearward from the connecting portion with the disk portion 22c ′.

  Further, the piston 140 constituting the hydraulic servo device of the third clutch 33 includes an inner pressure receiving portion 141 located immediately after the disc portion 22c ′ of the carrier 22c, and a tip portion of the piston 140 which is the friction plate 131, The outer peripheral friction plate pressing portion 142 is located immediately after the 132 row, and the cylindrical portion 143 is provided between them and extends from the outer peripheral end of the pressure receiving portion 141 to the rear side.

  In addition, a disc-shaped seal plate 150 is disposed immediately after the piston 140, and the rear end portion of the sleeve 22c ″ of the carrier 22c is prevented from coming out rearward by a snap ring 151. It is locked with.

  A seal member 152 formed of a lip seal attached to the outer peripheral portion of the seal plate 150 is in sliding contact with the inner peripheral surface of the cylindrical portion 143 of the piston 140, whereby the seal plate 150 and the sleeve of the carrier 22c. 22c ″ and the pressure receiving portion 141 and the cylindrical portion 143 of the piston 140 define a hydraulic chamber 160 constituting a hydraulic servo device, and an oil passage 161 provided in the end cover 4 is formed in the hydraulic chamber 160. Oil pressure is supplied through an oil passage 162 provided in the sleeve member 5 and an oil passage 163 provided in the sleeve 22c ″.

  Further, between the pressure receiving portion 141 of the piston 140 and the disc portion 22c ′ of the carrier 22c, the piston is operated in the direction opposite to the direction in which the hydraulic pressure supplied to the hydraulic chamber 160 is applied (clutch engagement direction) (clutch release direction). A return spring 170 that biases 140 is attached.

  Further, an inner peripheral side sealing member 144 formed of a lip seal that is in sliding contact with the outer peripheral surface of the sleeve 22c ″ of the carrier 22c is mounted on the inner peripheral portion of the pressure receiving portion 141 of the piston 140, and the outer periphery of the pressure receiving portion 141 is also provided. The outer peripheral side sealing member 145 made of the same lip seal that is slidably in contact with the inner peripheral surface of the extension cylindrical portion 121 of the hub 120 is attached to the portion, whereby the pressure receiving portion 141 of the piston 140 and the disc portion of the carrier 22c. The balance chamber 180 is defined by 22c ′ and the sleeve 22c ″ and the extended cylindrical portion 121 of the hub 120.

  Then, hydraulic oil is supplied to the balance chamber 180 through the oil passage 181 provided in the end cover 4, the oil passage 182 provided in the sleeve member 5, the oil passage 183 provided in the sleeve 22c ″ of the carrier 22c, and the like. When a hydraulic pressure is not supplied to the hydraulic chamber 160, a force in the clutch fastening direction that acts on the piston 140 due to the centrifugal force that acts on the hydraulic oil remaining in the hydraulic chamber 160 is introduced into the balance chamber 180. It cancels out by the force in the clutch release direction due to the centrifugal force of the working oil.

  Further, a disc portion 111 extending inwardly is integrally formed at the front end portion of the clutch drum 110 of the third clutch 33, and the inner peripheral portion of the disc portion 111 is connected to the power transmission member 112. It is connected. The power transmission member 112 extends forward and is connected to the sun gear 23a of the third planetary gear set 23 shown in FIG. 1, and the transmission gear mechanism 20 is connected via the third planetary gear set 23 and the fourth planetary gear set 24. It is led to the output gear 25 which takes out power from the.

  Further, in this embodiment, the second brake 42 is disposed on the outer periphery of the third clutch 33.

  The second brake 42 extends from the outer periphery of the end cover 4 to the front side and is housed inside a cylindrical fitting portion 4b fitted inside the rear end opening of the transmission case 3. A plurality of friction plates 42a... 42a having teeth on the outer peripheral side in splines respectively formed on the inner peripheral surface of the fitting portion 4b and the outer peripheral surface of the clutch drum 33a of the third clutch 33 opposed thereto. The plurality of friction plates 42b... 42b having teeth on the inner peripheral side are alternately engaged.

  A piston 42c is disposed on the front surface of the outer peripheral portion of the end cover 4, and two internal and external hydraulic chambers 42d and 42e are supplied with hydraulic pressure from an oil passage (not shown) between the piston 42c and the front surface of the end cover 4. Is provided. Further, the cylindrical fitting portion 4b is provided with notches at a plurality of locations in the circumferential direction, and the return spring 42f of the piston 42c is accommodated.

  Here, as described above, the member to be braked of the second brake 42 also serves as the drum 110 of the third clutch 33. Therefore, the drum 110 of the third clutch 33 is fixed when the brake 42 is operated. Accordingly, the sun gear 23a of the third planetary gear set 23 shown in FIG. 1 is fixed.

  Next, the operation of this embodiment will be described.

  As described above, the rotation of the turbine shaft 17 that extracts the output of the torque converter 10 is input to the ring gear 22d of the second planetary gear set 22 via the second connecting member 22f and the first connecting member 22e. Since the sun gear 22a of the planetary gear set 22 is fixed to the boss portion 4a of the end cover 4, the rotation input to the ring gear 22d is decelerated and output to the carrier 22c.

  Then, if the third clutch 33 is engaged and the second brake 42 is released, the rotation output to the carrier 22c is transmitted from the hub 120 of the third clutch 33 to the drum 110 and the power transmission member 112. Is transmitted to the sun gear 23a of the third planetary gear set 23, and according to the state of the other friction elements, as shown in Table 1, the third speed, the fifth speed, and the reverse speed are realized, and the difference from the output gear 25 is achieved. It is output to the moving device 60 side.

  In that case, according to the above configuration, the rotation of the turbine shaft 17 is input from the front side of the second planetary gear set 22 to the ring gear 22d and output from the rear side via the carrier 22c, and this output rotation is also transmitted to the planetary gear. This is input to the clutch hub 120 of the third clutch 33 arranged on the outer periphery of the set 22. That is, the rotation of the third clutch 33 is input from the rear side to the clutch hub 120 and output from the clutch drum 110 to the front side.

  Then, on the rear side of the second planetary gear set 22, the disk portion 22c ′ and the sleeve 22c ″ of the carrier 22c and the clutch hub 120 are integrated, and the sleeve 22c ″ of the integrated member, A hydraulic chamber 160 is configured by the seal plate 150 locked to the sleeve 22c ″ and the pressure receiving portion 141 on the inner peripheral portion of the piston 140 slidably fitted to the sleeve 22c ″. The hydraulic servo device is provided on the 120 side.

  Accordingly, the space on the rear side of the second planetary gear set 22 can be reduced as compared with the case where the piston is housed in the clutch drum having a large diameter or the hydraulic chamber is provided, and the rear side of the transmission (the anti-engine side). ) Is configured compactly.

  Further, since the balance chamber 180 is formed inside the extended cylindrical portion 121 obtained by extending the clutch hub 120 to the rear side, the balance chamber can be configured more compactly than the case where the balance chamber is provided in a clutch drum having a large diameter. This also makes the transmission more compact.

  Further, in addition to the disk portion 22c ′ and the sleeve 22c ″ constituting the carrier 22c, including the clutch hub 120, these are integrated, so that the number of parts and assembly man-hours are reduced, and The second brake 42 for fixing the clutch drum 110 of the three clutch 33 to the transmission case 3 is provided so as to overlap the outer periphery of the third clutch 33 in the axial direction. In comparison, the axial dimension of the transmission is shortened.

  Next, another embodiment of the seal structure of the hydraulic chamber and balance chamber of the present invention will be described.

  First, in the embodiment shown in FIG. 3, an O-ring 251 is attached as a seal member to the outer peripheral end of the seal plate 250, and this O-ring 251 is a cylindrical portion provided at the radial intermediate portion of the piston 240. By sliding contact with the outer peripheral surface of 241, the outer peripheral portion of the hydraulic chamber 260 is sealed.

  In the embodiment shown in FIG. 4, a lip seal 341 is attached as a sealing member to the intermediate portion in the radial direction of the piston 340, and the lip seal 341 is a cylindrical portion 351 provided at the outer peripheral end of the seal plate 350. The outer peripheral portion of the hydraulic chamber 360 is sealed by being in sliding contact with the inner peripheral surface.

  Further, in the embodiment shown in FIG. 5, an O-ring 441 is mounted as a seal member at the intermediate portion in the radial direction of the piston 440, and this O-ring 441 is a cylindrical portion 451 provided at the outer peripheral end of the seal plate 450. The outer peripheral portion of the hydraulic chamber 460 is sealed by being in sliding contact with the outer peripheral surface.

  On the other hand, regarding the seal structure of the balance chamber, in the embodiment shown in FIG. 6, an O-ring 542 as a seal member is attached to the inner peripheral portion of the friction plate pressing portion 541 in the piston 540, and this is the clutch hub 520. The outer peripheral portion of the balance chamber 580 is sealed by being in sliding contact with the outer peripheral surface of the extended cylindrical portion 521.

  Further, in the embodiment shown in FIG. 7, an O-ring 622 as a seal member is mounted on the inner peripheral surface of the extension cylindrical portion 621 of the clutch hub 620, and this is used for sealing the hydraulic chamber at the radial intermediate portion of the piston 640. The outer peripheral portion of the balance chamber 680 is sealed by sliding contact with the outer peripheral surface of the cylindrical portion 641.

  Further, in the embodiment shown in FIG. 8, an O-ring 722 as a seal member is mounted on the outer peripheral surface of the extended cylindrical portion 721 of the clutch hub 720, and this is the directly inner peripheral side of the friction plate pressing portion 741 in the piston 740. The outer peripheral portion of the balance chamber 780 is sealed by being in sliding contact with the inner peripheral surface of the cylindrical portion 742 provided on the outer periphery.

  As described above, since the automatic transmission according to the present invention is configured in a compact manner, the automatic transmission may be suitably used in the field of manufacturing automobile automatic transmissions.

1 is a skeleton diagram showing an overall mechanical configuration of an automatic transmission according to an embodiment of the present invention. It is sectional drawing of the principal part of the embodiment. It is sectional drawing of other embodiment of the seal structure of a hydraulic chamber. It is sectional drawing of other embodiment of the seal structure of a hydraulic chamber. It is sectional drawing of other embodiment of the seal structure of a hydraulic chamber. It is sectional drawing of other embodiment of the seal structure of a balance chamber. It is sectional drawing of other embodiment of the seal structure of a balance chamber. It is sectional drawing of other embodiment of the seal structure of a balance chamber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic transmission 33 3rd clutch 22 2nd planetary gear set 22c Carrier 22c 'Disk part 22c "Sleeve 110 Clutch drum 120 Clutch hub 140 Piston 150 Seal plate 160 Hydraulic chamber 180 Balance chamber

Claims (5)

A planetary gear set in which a sun gear is fixed to a boss portion extending in the axial direction at the shaft center portion of the transmission case, rotation is input from one end of the ring gear, and rotation is output from the other end via a carrier;
A power transmission member disposed on the one end side of the planetary gear set and connected to an output member;
An automatic transmission provided on the outer periphery of the planetary gear set, and including a clutch drum, a clutch hub, and a clutch having a hydraulic servo device that fastens a friction plate disposed therebetween,
A carrier of the planetary gear set and a clutch hub of the clutch are coupled on the other end side of the planetary gear set;
And the clutch drum of the clutch and the power transmission member are connected,
The automatic transmission, wherein the hydraulic servo device is provided on the clutch hub or a member connected to the clutch hub. The automatic transmission according to claim 1,
On the other end side of the planetary gear set, a disc portion whose outer peripheral portion is connected to the clutch hub, and a sleeve connected to the inner peripheral portion of the disc portion and rotatably disposed on the boss portion Is provided,
An inner periphery of a piston constituting the hydraulic servo device is slidably fitted to the outer periphery of the sleeve,
On the other end side, a seal plate that is prevented from moving to the other end side is locked,
And between the outer peripheral portion of the seal plate and the intermediate portion in the radial direction of the piston, both sliding contact portions are provided,
An automatic transmission characterized in that a hydraulic chamber constituting the hydraulic servo device is formed by the seal plate, an inner peripheral portion of a piston, and the sleeve. The automatic transmission according to claim 2, wherein
A cylindrical portion that extends the clutch hub to the other end side is provided,
A sliding contact portion is provided between the cylindrical portion and the piston;
An automatic transmission characterized in that a balance chamber is formed by the cylindrical portion, the piston, the disc portion, and the sleeve. In the automatic transmission according to claim 2 or 3,
The automatic transmission, wherein the disk portion and the sleeve are integrated to form the carrier, and the clutch hub is provided integrally therewith. In the automatic transmission according to any one of claims 1 to 4,
A brake for fixing the clutch drum of the clutch to the transmission case;
An automatic transmission characterized in that the brake is provided so as to overlap the outer periphery of the clutch in the axial direction.

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