JP6454558B2 - Friction engagement device - Google Patents

Description

  The present invention relates to a friction engagement device such as a clutch or a brake included in a transmission of a vehicle, and more particularly to a friction engagement device having a structure for preventing a plate from coming off.

  An automatic transmission mounted on a vehicle includes a hydraulic friction engagement device (clutch or brake). As this type of friction engagement device, for example, as shown in Patent Document 1, a housing (casing) of the friction engagement device, a plurality of friction plates arranged in the housing, and a stack of the plurality of friction plates. Provided with an end plate arranged at one end in the direction, a hydraulic piston for pressing a plurality of friction plates from the other end in the stacking direction to the end plate, and a return spring installed between the hydraulic piston and the end plate There is. The hydraulic piston presses the friction plate by moving toward the end plate with the hydraulic pressure of the hydraulic oil, and moves in a direction away from the friction plate by the urging force of the return spring.

  Here, when the plurality of friction plates are assembled to the housing together with the end plate, the assemblability is improved by configuring the end plates so that they do not fall out of the housing. In Patent Document 1, a groove for fitting a circlip is formed on the inner periphery of the end portion on the end plate side of the housing, and the circlip is fitted on the inner periphery of the end portion on the end plate side of the housing. It was. By providing the circlip, it is possible to prevent the end plate assembled to the housing from falling off, and to prevent the plate held by the end plate from falling off.

  However, since the circlip is a member arranged to prevent the end plate from falling off during assembly, it becomes an unnecessary part after assembly. In addition, there is a problem in that miniaturization of the housing is hindered by assembling a member unnecessary for driving in the housing in order to ensure assembly. Moreover, if the process of assembling the circlip is essential, the number of man-hours required for assembling will be increased.

JP 2014-185767 A

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a friction engagement device that can achieve assembling performance with a small number of members.

  In order to solve the above problems, a friction engagement device (CR, CL) according to the present invention includes a housing (21), a hub (22) splined inside the housing (21), and an inner periphery of the housing (21). A plurality of circular annular pressure plates (23) formed on the outer periphery, and an outer periphery of the hub (22) are formed on the outer periphery. A plurality of circular annular friction plates (24) having engagement teeth (24a) that engage with the engagement grooves (22a) formed on the inner periphery and interposed between the plurality of pressure plates (23), and pressure The plate (23) and the friction plate (24) are arranged at one end in the stacking direction and are engaged with the engagement groove (21a) of the housing (21) or the engagement groove (22a) of the hub (22). The engagement teeth (25a) are formed. Friction engagement device (CR, CL) comprising a plate plate (25), and a pressing member (33) for pressing the end plate (25) in the laminating direction of the pressure plate (23) and the friction plate (24) The end plate (25) is configured to be rotatable relative to the pressure plate (23) and the friction plate (24), and the engagement grooves (21a, 22a) have engagement teeth of the end plate (25). The restricting portions (21b, 22b) for restricting the movement in the stacking direction of (25a) are formed in a direction orthogonal to the engaging grooves (21a, 22a).

  Thus, the end plate (25) is configured to be rotatable relative to the pressure plate (23) and the friction plate (24), and the restricting portions (21b, 22b) are configured to be engaged with the engaging grooves (21a, 22a). If the engaging teeth (25a) are arranged at positions restricted by the restricting portions (21b, 22b) at the time of assembly, the engaging teeth (25a) in the stacking direction are formed. The movement is restricted and the end plate (25) does not fall out of the housing (21). Further, by rotating the housing (21) after assembly, the engaging teeth (25a) are detached from the restricting portions (21b, 22b) and enter the engaging grooves (21a, 22a). Here, the end plate (25) is a member pressed by the pressing member (33), and is a member used for fastening and releasing of the clutch. As described above, the engagement teeth (25a) of the end plate (25) are used. ) Is movable, it is possible to add an action of preventing falling out. This eliminates the need for a member that is used exclusively to prevent falling out, unlike the conventional circlip, and the number of members can be reduced. Therefore, securing of assembling property can be realized with a small number of members.

  The engaging teeth (25a) are located at the restriction position (L1) where the movement in the axial direction is restricted by the restriction portions (21b, 22b) when the pressure plate (23) and the friction plate (24) are assembled. It is good also as moving to the engaging position (L2) engaged with an engaging groove (21a, 22a) by (21) and a hub (22) rotating relatively. In this way, if the housing (21) and the hub (22) are rotated relative to each other to change the position of the engaging teeth (25a), the housing (21) and the hub (22) rotate relative to each other after assembly. Then, the engagement tooth (25a) can be brought into the engagement position (L2), and the number of assembly steps can be reduced.

Further, the engaging tooth (25a) is moved from the restricting position (L1) to the engaging position (L2) by the relative rotation of the housing (21) and the hub (22), and by the pressing member (33). If it is configured to press in the stacking direction, the pressing member (33) continues to press the end plate (25) at the engaging position (L2), so that the engaging teeth (25a) are irreversibly engaged with the engaging groove (21a). , 22a). Thereby, it is possible to reliably prevent the end plate (25) from coming off from the housing (21) and the hub (22).
In addition, the code | symbol in said parenthesis has shown the code | symbol of the corresponding component of embodiment mentioned later as an example of this invention.

  According to the friction engagement device according to the present invention, it is possible to ensure assembling performance with a small number of members.

1 is a main cross-sectional view showing a driving force transmission device having a clutch according to an embodiment of the present invention. It is an expanded sectional view showing detailed composition around a clutch (right clutch). It is a perspective view which shows the external appearance of a clutch (left clutch). It is a perspective view of a clutch housing, (a) is a whole perspective view, (b) is an enlarged view (Z view) which shows the relationship between a spline inner groove | channel and a control part. It is sectional drawing of a clutch housing, (a) is whole sectional drawing, (b) is an expanded sectional view. It is an expansion perspective view which shows the positional relationship of a pressure plate and an end plate, (a) is a figure which shows the state in which the phase of the engagement tooth of a pressure plate and an end plate was equal, (b) is a pressure plate and an end It is a figure which shows the state from which the phase of the engagement tooth of the plate differed. It is a figure which shows the engagement state of an end plate at the time of plate assembly | attachment, and a clutch housing, (a) has just inserted the plate in the clutch housing, (b) has shown the state which took the measure of prevention. It is a figure which shows the engagement state of the end plate at the time of torque transmission, and a clutch housing, (a) shows the state of prevention of a disconnection, (b) shows the state where cancellation | release of the prevention of release was performed. It is an expanded sectional view of the clutch periphery which concerns on other embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a main cross-sectional view showing a driving force transmission device having clutches CR and CL (friction engagement devices) according to an embodiment of the present invention. In the present embodiment, an example in which the clutches CR and CL are applied to the driving force transmission device 1 is shown. The driving force transmission device 1 includes a pinion shaft 2 connected to a propeller shaft (not shown) that is rotationally driven by a driving force transmitted from an engine (not shown), and a pinion formed at the tip of the pinion shaft 2 A gear 3 and a ring gear 4 meshing with the pinion gear 3 are provided. The ring gear 4 is attached to the outer periphery of a hollow rotary input shaft 5 that is arranged coaxially with the left axle 6L and the right axle 6R. Accordingly, when the pinion shaft 2 is rotationally driven via the engine and the propeller shaft, the driving force is transmitted to the rotational input shaft 5 via the pinion gear 3 and the ring gear 4 so that the rotational input shaft 5 rotates. It has become.

  In the rotation input shaft 5, a left clutch CL that transmits driving force between the rotation input shaft 5 and the left axle 6 </ b> L is provided at an end portion on the side where the ring gear 4 is attached. Is provided with a right clutch CR that transmits a driving force between the rotary input shaft 5 and the right axle 6R. The rotation of the rotation input shaft 5 is transmitted to the left clutch CL and the right clutch CR. A gear chamber 15 is formed in the casing 10 of the driving force transmission device 1 and is arranged at the center in the axial direction of the rotary input shaft 5. In addition, a pair of right clutch chamber 16 and left clutch chamber 17 disposed on both sides of the gear chamber 15 are formed on the left and right sides of the casing 10, respectively. Thus, the casing 10 of the driving force transmission device 1 has a three-divided chamber structure including the gear chamber 15, the pair of right clutch chambers 16, and the left clutch chamber 17.

  The gear chamber 15 is provided with the pinion gear 3 and the ring gear 4 described above. The right clutch chamber 16 has a right clutch CR, and the left clutch chamber 17 has a left clutch CL. Further, the right clutch chamber 16 is provided with a hydraulic oil supply unit 50 including a valve body 51 and a linear solenoid valve 52 for supplying hydraulic oil to the left clutch CL and the right clutch CR. The hydraulic fluid is supplied to the valve body 51 from an oil pump 54 that operates by driving a motor 53. Further, a hydraulic oil passage 55 is formed for guiding hydraulic oil from the valve body 51 and the linear solenoid valve 52 to the right clutch CR. The hydraulic oil passage 55 is formed to guide the hydraulic oil discharged from the valve body 51 and the linear solenoid valve 52 to the right clutch CR through the shaft of the rotary input shaft 5. Although illustration is omitted, the hydraulic oil that has flowed out of the valve body 51 and the linear solenoid valve 52 passes through the shaft of the rotary input shaft 5 and is also guided to the left clutch CL.

  An oil strainer 57 is installed in the gear chamber 15. The oil strainer 57 has a suction port (not shown) for sucking the working oil on the lower surface, and sucks the working oil accumulated in the gear chamber 15 from the suction port.

  FIG. 2 is an enlarged cross-sectional view showing a detailed configuration around the clutch (right clutch CR). FIG. 2 shows an enlarged view of the front half of the right clutch CR. The right clutch CR includes a substantially cylindrical clutch housing 21 (housing) coupled to the end of the rotary input shaft 5 and a clutch hub 22 (hub) splined to the end of the right axle 6R inside the clutch housing 21. ), And a pressure plate 23 and a friction plate 24, which are friction materials in which a plurality of layers are alternately stacked in the axial direction in the clutch housing 21. The pressure plate 23 has spline external teeth 23 a (engagement teeth) at the outer peripheral end, and the spline external teeth 23 a are connected to the spline inner grooves 21 a (engagement grooves) formed on the inner periphery of the clutch housing 21. Match. On the other hand, the friction plate 24 has spline inner teeth 24a (engagement teeth) at the inner peripheral end, and the spline inner teeth 24a are in contact with the spline outer grooves 22a (engagement grooves) formed on the outer periphery of the clutch hub 22. The spline is engaged.

  An end plate 25 is installed at the end of the cylinder piston 33 (pressing member) side in the stacking direction of the pressure plate 23 and the friction plate 24. The end plate 25 is disposed at one end in the stacking direction in which the pressure plate 23 and the friction plate 24 are stacked, and spline external teeth 25 a (engaging teeth) that engage with the spline inner grooves 21 a of the clutch housing 21 are formed. . The clutch housing 21 has an opening 21A at the end on the cylinder piston 33 side in the axial direction. A restriction groove 21b (regulation portion) formed in a direction orthogonal to the spline inner groove 21a is provided at the end of the opening 21A side of the inner spline groove 21a. This will be described in detail later. A clutch bearing 26 is installed between the clutch housing 21 and the clutch hub 22 so as to support them in a relatively rotatable manner.

  The cylinder piston 33 installed facing the opening 21 </ b> A is accommodated in the piston housing 41. The piston housing 41 is provided with a substantially circular opening 41d at the center thereof, and a cylindrical flange 41c projecting toward the right clutch CR along the axial direction is provided around the opening 41d. Is formed.

  An accommodating portion 43 that accommodates the cylinder piston 33 is formed on the outer diameter side of the flange portion 41c. The accommodating portion 43 is a circular annular recess formed by recessing the surface on the pressure plate 23 and friction plate 24 side of the piston housing 41 in the axial direction. The cylinder piston 33 is a plate-like member having a circular annular outer shape installed in the housing portion 43. A thrust needle bearing 29 is interposed between the cylinder piston 33 and the end plate 25, and the cylinder piston 33 and the end plate 25 are capable of relative rotation and can be moved integrally in the axial direction. A piston chamber 42 for generating hydraulic pressure by hydraulic oil is defined in the gap between the inner surface of the accommodating portion 43 of the piston housing 41 and the cylinder piston 33. Although not shown, the piston chamber 42 communicates with an oil passage through which hydraulic oil from an oil pump 54 (see FIG. 1) is introduced.

  The structure of the clutch housing 21 and the end plate 25 of the clutch will be described in detail. First, the external appearance around the clutch housing 21 will be described. FIG. 3 is a perspective view showing an appearance of the clutch (left clutch CL). Although the left clutch CL is illustrated in FIG. 3, the right clutch CR has the same configuration and only the rotation direction is different. As shown in FIG. 3, a clutch housing 21 is disposed outside the clutch, and a clutch hub 22 is disposed in the center of the opening 21A. A plurality of circular annular pressure plates 23 and friction plates 24 are alternately inserted on the inner peripheral side of the clutch housing 21 and on the outer peripheral side of the clutch hub 22 (see FIGS. 1 and 2). In this case, as described above, the pressure plate 23 engages with the spline inner groove 21 a of the clutch housing 21, and the friction plate 24 engages with the spline outer groove 22 a of the clutch hub 22. A spline outer tooth 25 a of the end plate 25 is engaged with a spline inner groove 21 a of the clutch housing 21 at the front end of the opening 21 </ b> A of the clutch housing 21.

  Further, since the end plate 25 is configured to be rotatable relative to the clutch housing 21, the end plate 25 can rotate in the directions of arrows Ra and Rb shown in FIG. For example, the clutch housing 21 rotates in the direction of the arrow R1 at the time of main input of the driving force. In this case, the end plate 25 rotates in the direction of the arrow Ra that is relatively opposite to the direction of the arrow R1.

  A configuration of the clutch housing 21 to which the pressure plate 23 and the end plate 25 are assembled will be described. FIG. 4 is a perspective view of the clutch housing 21, (a) is an overall perspective view, and (b) is an enlarged view (Z view) showing the relationship between the spline inner groove 21 a and the regulation groove 21 b. FIG. 4A shows a state in which the clutch hub 22 and the end plate 25 of FIG. 3 are removed and the pressure plate and the friction plate are omitted. As shown in FIG. 4 (a), the direction in which the pressure plate 23 and the friction plate 24 are assembled to the entire inner circumference on the outer peripheral side of the clutch housing 21 having the opening 21A and formed in a substantially cylindrical shape (see FIG. (In the direction of arrow D1), an in-spline groove 21a is formed. Since the width of each spline inner groove 21a is equal to the width of the spline outer teeth 23a of the pressure plate 23, the clutch housing 21 and the pressure plate 23 are spline engaged.

  Further, as shown in FIG. 4B, each spline inner groove 21a has a restriction groove 21b at the end on the opening 21A side of the clutch housing 21 in a direction perpendicular to the spline inner groove 21a. It is formed. As will be described later, when the spline external teeth 25a of the end plate 25 enter, the regulation groove 21b is parallel to the stacking direction of the pressure plate 23 and the friction plate 24 (the assembly direction and the direction of the arrow D1 in FIG. 4A). Direction) will be restricted. Details of the movement of the end plate 25 will be described later. FIG. 5 is a cross-sectional view of the clutch housing 21, (a) is an overall cross-sectional view, and (b) is an enlarged cross-sectional view. The cross sections in FIGS. 5A and 5B correspond to the AA cross section in FIG. As shown in FIG. 5A, when the clutch housing 21 is viewed from the opening 21 </ b> A side, the regulation groove 21 b is formed adjacent to the spline inner groove 21 a over the entire circumference of the clutch housing 21.

  The positional relationship between the spline external teeth 25a of the end plate 25 and the spline external teeth 23a of the pressure plate 23 will be described. FIG. 6 is an enlarged perspective view showing the positional relationship between the pressure plate 23 and the end plate 25, and (a) is a diagram showing a state in which the phases of the engaging teeth of the pressure plate 23 and the end plate 25 are aligned, (B) is a figure which shows the state from which the phase of the engagement tooth of the pressure plate 23 and the end plate 25 differed. The spline external teeth 23a formed on the plurality of pressure plates 23 are assembled in the spline inner groove 21a (see FIG. 5) of the clutch housing 21 in the direction of the arrow D1 in the figure, and all are connected to the spline inner groove 21a. Since they are engaged, the phases of the spline external teeth 23a of the plurality of pressure plates 23 are always aligned as shown in FIGS. 6 (a) and 6 (b). On the other hand, the end plate 25 is configured to be rotatable relative to the pressure plate 23 and the friction plate 24 as described above. Thereby, the spline external teeth 25a of the end plate 25 rotate relative to the spline external teeth 23a of all the pressure plates 23. The friction plate 24 is engaged with the spline outer groove 22a of the clutch hub 22 by spline inner teeth 24a (see FIG. 2), and the phases of all the spline inner teeth 24a are aligned.

  The engagement of the end plate 25 with the clutch housing 21 during assembly will be described with reference to FIGS. 7A and 7B are diagrams showing the engagement state of the end plate 25 and the clutch housing 21 when the plate is assembled. FIG. 7A shows a state in which the plate has just been inserted into the clutch housing 21, and FIG. Indicates the taken state. First, when the pressure plate 23, the friction plate 24, and the end plate 25 are assembled to the clutch housing 21, the pressure plate 23 and the friction plate 24 are alternately stacked, and the assembly direction (the arrow D1 in FIG. 6A). Direction). In this case, since the spline external teeth 23a of the pressure plate 23 and the spline external teeth 25a of the end plate 25 are both assembled along the spline internal groove 21a of the clutch housing 21, the phase of the spline external teeth 23a and the spline external teeth 25a Are the aligned state (the state of FIG. 6A). In this state, the spline outer teeth 25a of the end plate 25 are engaged with the spline inner grooves 21a of the clutch housing 21 like the spline outer teeth 23a, as shown in FIG. This is the engagement position L2 at which the spline outer teeth 25a engage with the spline inner groove 21a.

  Here, as shown in FIG. 7B, when the end plate 25 is rotated in the direction of the arrow Rb, the spline external teeth 25a of the end plate 25 are rotated in the direction of the arrow Rb, and are fitted into the restriction grooves 21b of the clutch housing 21. Get stuck. Since the regulation groove 21b is formed only in the direction orthogonal to the spline inner groove 21a, the spline external teeth 25a fitted in the regulation groove 21b move in the assembly direction (the direction of arrow D1 in FIG. 6A). There is no. This is defined as a restriction position L1 where movement of the spline outer teeth 25a in the assembly direction is restricted. Thus, by restricting the movement of the end plate 25 on the end side of the opening 21A of the clutch housing 21 in the assembling direction, the pressure plate 23 and the friction plate 24 assembled so as to be alternately stacked are used as the end plate. 25 and prevents the pressure plate 23 and the friction plate 24 from coming off.

  The engagement of the end plate 25 with the clutch housing 21 during torque transmission will be described with reference to FIGS. FIGS. 8A and 8B are diagrams showing an engagement state between the end plate 25 and the clutch housing 21 during torque transmission. FIG. 8A shows a state in which the end plate is prevented, and FIG. 8B shows a state in which the release prevention is released. In a state in which measures for preventing the disconnection are taken, as shown in FIG. 8A, the spline outer teeth 25a remain at the restriction position L1.

  Here, when the rotation input shaft 5 (see FIG. 1) rotates (main rotation), as shown in FIG. 8B, the clutch housing 21 rotates in the arrow R1 direction during torque transmission. Along with this, the pressure plate 23 and the friction plate 24 engaged with the clutch housing 21 also rotate in the arrow R1 direction. Here, although the end plate 25 is pressed by the cylinder piston 33 (see FIG. 2) and does not move, the end plate 25 rotates relative to the clutch housing 21 in the direction of the arrow Ra. As a result, the spline outer teeth 25a move to the engagement position L2 that engages with the spline inner groove 21a of the clutch housing 21. Further, since the end plate 25 is pressed by the cylinder piston 33 as described above, the pressure plate 23 and the friction plate 24 are stacked after moving to the engagement position L2 shown in FIG. Pressed in the direction.

  As described above, in the clutches CR and CL of the present embodiment, the end plate 25 is configured to be rotatable relative to the pressure plate 23 and the friction plate 24, and the regulation groove 21b is orthogonal to the spline inner groove 21a. Therefore, if the spline external teeth 25a are arranged at the positions restricted by the restriction grooves 21b during assembly, the movement of the spline external teeth 25a in the stacking direction is restricted, and the end plate 25 becomes the clutch. It does not fall out of the housing 21. Further, by rotating the clutch housing 21 after the assembly, the spline outer teeth 25a are detached from the restriction grooves 21b and enter the spline inner grooves 21a. Here, the end plate 25 is a member that is pressed by the cylinder piston 33, and is a member that is used for fastening and releasing of the clutch. By making the spline external teeth 25a of the end plate 25 movable as described above. In addition, it is possible to add an action for preventing dropout. This eliminates the need for a member that is used exclusively to prevent falling out, unlike the conventional circlip, and the number of members can be reduced. Therefore, securing of assembling property can be realized with a small number of members.

  Further, the spline outer teeth 25a are located at the restriction position L1 where the movement in the axial direction is restricted by the restriction groove 21b when the pressure plate 23 and the friction plate 24 are assembled, and the clutch housing 21 and the clutch hub 22 rotate relative to each other. It is good also as moving to the engaging position L2 engaged with the groove | channel 21a in a spline. As described above, if the clutch housing 21 and the clutch hub 22 are rotated relative to each other to change the position of the spline external teeth 25a, the spline external teeth can be rotated if the clutch housing 21 and the clutch hub 22 rotate relative to each other after assembly. 25a can be set to the engagement position L2, and the number of assembling steps can be reduced.

  Further, the spline external teeth 25a are moved from the restricting position L1 to the engaging position L2 by the relative rotation of the clutch housing 21 and the clutch hub 22, and pressed in the stacking direction by the cylinder piston 33. Since the cylinder piston 33 continues to press the end plate 25 at the engagement position L2, the spline outer teeth 25a are irreversibly kept in the spline inner groove 21a. Thereby, the end plate 25 can be reliably prevented from coming off from the clutch housing 21.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Deformation is possible.

  For example, although the end plate 25 is engaged with the clutch housing 21 in the above-described embodiment, it may be performed with respect to the clutch hub 22. FIG. 9 is an enlarged cross-sectional view of the periphery of a clutch according to another embodiment. As shown in FIG. 9, the spline inner groove 25a of the end plate 25 is formed in the spline outer groove 22a of the clutch hub 22, and the restriction groove 22b (regulator) for restricting the movement in the stacking direction is replaced with the spline outer groove 22a. It is good also as forming in the direction orthogonal to.

DESCRIPTION OF SYMBOLS 1 ... Driving force transmission device 2 ... Pinion shaft 3 ... Pinion gear 4 ... Ring gear 5 ... Rotation input shaft 6L ... Left axle 6R ... Right axle 16 ... Right clutch chamber 17 ... Left clutch chamber 21 ... Clutch housing 21A ... Opening 21a ... Spline inner groove (engagement groove)
21b ... Restriction groove 22 ... Clutch hub 22a ... Spline outer groove (engagement groove)
22b ... Regulator 23 ... Pressure plate 23a ... Spline external teeth (engagement teeth)
24 ... friction plate 24a ... spline internal teeth (engaging teeth)
25 ... End plate 25a ... Spline external teeth (engaging teeth)
25b ... Spline internal teeth (engagement teeth)
29 ... Thrust needle bearing 33 ... Cylinder piston 41 ... Piston housing CL ... Left clutch CR ... Right clutch D1 ... Assembly direction (stacking direction of pressure plate 23 and friction plate 24)
L1 ... Restriction position L2 ... Engagement position

Claims (2)

A housing;
A hub that is splined inside the housing, and a plurality of circular annular pressure plates that are formed on the outer periphery with engaging teeth that engage with an engaging groove formed on the inner periphery of the housing;
A plurality of circular annular friction plates having engagement teeth that engage with engagement grooves formed on the outer periphery of the hub and are interposed between the plurality of pressure plates;
An end plate that is disposed at one end in the stacking direction in which the pressure plate and the friction plate are stacked, and in which an engagement tooth that engages with the engagement groove of the housing or the engagement groove of the hub is formed;
A friction engagement device comprising: a pressure member that presses the end plate in the stacking direction of the pressure plate and the friction plate;
The end plate is configured to be rotatable relative to the pressure plate and the friction plate,
In the engagement groove, a restricting portion for restricting movement of the engagement teeth of the end plate in the stacking direction is formed in a direction orthogonal to the engagement groove ,
The engagement teeth of the end plate are positioned at a restriction position where movement in the axial direction is restricted by the restriction portion when the pressure plate and the friction plate are assembled, and the housing and the hub rotate relative to each other. A friction engagement device, wherein the friction engagement device moves to an engagement position to engage with an engagement groove . The engagement teeth of the end plate are moved from the restriction position to the engagement position by the relative rotation of the housing and the hub, and are pressed in the stacking direction by the pressing member. The friction engagement device according to claim 1, wherein:

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