JP2016008627A - Multi-plate frictional fastening element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate manufacturability or assemblability with a single plate while eliminating a space in a radial direction.SOLUTION: There are provided a plurality of drive discs 3 spline fitted to a clutch hub 1, a plurality of driven discs 4 spline fitted to a clutch drum 2, and a clutch piston 5 for applying fastening force pressing against the disc sliding surfaces in a group of discs alternatively arranged. This wet multiple disc clutch C is formed in such a way that each of the adjoining disc clearance spaces of the driven discs 4 includes torsion bar springs 6. The torsion bar springs 6 have their circumferential lengths exceeding half of the disc circumferential length, and a point of application of each of the spring loads for pulling away the adjoining driven discs 4 corresponds to opposing spline teeth 4a of the driven discs 4.

Description

  The present invention relates to a multi-plate friction fastening element having an elastic body that equalizes axial spaces of a plurality of friction plates.

  2. Description of the Related Art Conventionally, a multi-plate clutch having elastic spacer means in which a riveted plate spring or rubber is welded to a single driven plate is known (for example, see Patent Document 1). There is also known a wet multi-plate clutch in which an annular wave spring having engaging portions at both ends is engaged with an engaged portion formed on an adjacent driven plate (see, for example, Patent Document 2).

JP 60-78115 A JP-A-4-307122

  However, in the multi-plate clutch described in Patent Document 1, the elastic spacer means is attached to each spline tooth portion called a claw of the driven plate. For this reason, there is a problem that the productivity of the driven plate alone is poor and the assembling property to the unit is also poor. In addition, in the multi-plate clutch described in Patent Document 2, the problem of assembling to the unit is solved, but before assembling to the unit, a plurality of driven plates are engaged with wave springs. Sub assembly to connect is necessary. Further, since the structure is such that the spring load is output by a single wave spring, there is a problem that a radial space for applying the spring load is required in the plate body portion of the driven plate.

  The present invention has been made paying attention to the above-mentioned problem, and provides a multi-plate friction fastening element that can facilitate manufacturability and assemblability of a single plate while eliminating a radial space. Objective.

In order to achieve the above object, a multi-plate friction fastening element according to the present invention includes a first member and a second member arranged to face a power transmission path, a plurality of first friction plates, a plurality of second friction plates, A piston member.
The plurality of first friction plates are spline-fitted to spline teeth formed on the first member.
The plurality of second friction plates are spline-fitted to spline teeth formed on the second member, and are disposed between the adjacent first friction plates.
The piston member is provided at an end position of a plate group in which the first friction plate and the second friction plate are alternately arranged, and provides a fastening force that presses the plate sliding surface.
In this multi-plate friction fastening element, an elastic body is interposed in each of the plate gap spaces adjacent to the second friction plate. The elastic body has a circumferential length that is more than half of the circumferential length of the plate, and the point of action of the spring load that separates the adjacent second friction plates is the spline tooth portion facing the second friction plate. A certain shape.

Therefore, an elastic body is interposed in each plate gap space adjacent to the second friction plate. This elastic body has a shape in which the circumference is more than half of the circumference of the plate, and the point of action of the spring load that separates the adjacent second friction plates is the opposing spline teeth of the second friction plate It is said.
That is, the point of action of the spring load that separates the adjacent second friction plates is a shape that is a spline tooth portion of the second friction plate. For this reason, it is not necessary to secure a radial space for applying a spring load to the plate body portion of the second friction plate.
And it is set as the structure which only inserts an elastic body in the plate gap space which the 2nd friction plate adjoins. For this reason, it is not necessary to fix the elastic body to the single unit of the second friction plate, and when assembling to the unit, it is only necessary to repeat the work of assembling the first friction plate, the second friction plate, and the elastic body in a predetermined order. At the time of this assembling operation, the circumferential length of the elastic body is set to a length exceeding half of the circumferential length of the plate, so that the assembled elastic body is held in the plate gap space without dropping off. Therefore, manufacturability with a single plate is facilitated, and assembly to the unit is facilitated.
As a result, it is possible to facilitate the manufacturability and assemblability of the plate alone while eliminating the need for a radial space.

1 is an overall cross-sectional view showing a wet multi-plate clutch (an example of a multi-plate friction engagement element) according to a first embodiment. It is the sectional view on the AA line of FIG. 1 which shows the torsion bar spring interposed in the driven plate which the wet multi-plate clutch of Example 1 adjoins. It is the B section enlarged view of FIG. 1 which shows the torsion bar spring interposed by the driven plate which the wet multi-plate clutch of Example 1 adjoins. It is a partially expanded perspective view which shows the torsion bar spring interposed in the driven plate which the wet multi-plate clutch of Example 1 adjoins. 3 is a cross-sectional view of a main part showing a multi-plate clutch of Comparative Example 1. FIG. 6 is a cross-sectional view of a main part showing a multi-plate clutch of Comparative Example 2. FIG. It is explanatory drawing which shows the wave spring of the multi-plate clutch of the comparative example 2. It is sectional drawing which shows the other example of the torsion bar spring interposed by the driven plate which the wet multi-plate clutch of Example 1 adjoins.

  Hereinafter, the best mode for realizing the multi-plate friction fastening element of the present invention will be described based on Example 1 shown in the drawings.

First, the configuration will be described.
The configuration of the wet multi-plate clutch C (an example of a multi-plate frictional engagement element) in the first embodiment will be described by dividing it into “overall configuration” and “main configuration”.

[overall structure]
FIG. 1 is an overall cross-sectional view of a wet multi-plate clutch C according to a first embodiment. The overall configuration will be described below with reference to FIG.

  As shown in FIG. 1, the wet multi-plate clutch C includes a clutch hub 1 (first member), a clutch drum 2 (second member), a drive plate 3 (first friction plate), and a driven plate 4 ( A second friction plate), a clutch piston 5 (piston member), and a torsion bar spring 6 (elastic body).

  The clutch hub 1 and the clutch drum 2 overlap in the axial direction in the power transmission path and face each other with a predetermined interval in the radial direction. The clutch hub 1 is connected to the drive source side, and spline teeth 1a are formed by external teeth on a facing surface facing the clutch drum 2 in the radial direction. The clutch drum 2 is connected to the drive wheel side, and spline teeth 2a formed by internal teeth are formed on a facing surface facing the clutch hub 1 in the radial direction.

  The drive plate 3 is a donut-shaped plate prepared in a plurality, and is spline-fitted to the spline teeth 1a formed on the clutch hub 1, and rotates around the rotation center line CL when the clutch hub 1 rotates. . On the inner periphery of the drive plate 3, a spline tooth portion 3a that is fitted to the spline tooth 1a is formed. Clutch facings 3b are affixed to both sides of the drive plate 3 in regions that become power transmission surfaces.

  The driven plate 4 is a donut-shaped plate prepared in plural, and is spline-fitted to the spline teeth 2a formed on the clutch drum 2, and rotates around the rotation center line CL when the clutch drum 2 rotates. . On the outer periphery of the driven plate 4, spline tooth portions 4 a that fit into the spline teeth 2 a are formed. A retainer plate 7 having the same shape as the driven plate 4 but having an increased thickness is disposed at the end opposite to the clutch piston 5 in the axial direction. The retainer plate 7 is formed on the spline teeth 2a. The axial movement is defined by the snap ring 8 provided in the ring groove.

  The clutch piston 5 is provided at an end position of a plate group in which the drive plates 3 and the driven plates 4 are alternately arranged, and applies a fastening force that presses the plate sliding surface to which the clutch facing 3b is attached. The clutch piston 5 is disposed in a piston cylinder portion 2b formed integrally with the clutch drum 2 so as to be capable of reciprocating in the axial direction. The piston end surface 5 a of the clutch piston 5 extends to a position where it comes into contact with the driven plate 4. The clutch piston 5 defines a piston oil chamber 11 by a first oil seal 9 and a second oil seal 10. When the clutch hydraulic oil is supplied to the piston oil chamber 11 from the clutch hydraulic oil hole 12 formed in the piston cylinder portion 2b, the clutch piston 5 strokes in the clutch engagement direction (right direction in FIG. 1). On the other hand, when the clutch hydraulic oil is removed from the piston oil chamber 11, the clutch is returned to the clutch release position by the urging force of the torsion bar spring 6 that also serves as a return spring.

  The torsion bar spring 6 is an elastic body that generates a spring load by using a repulsive force when a twist is applied in the direction around the axis of the metal wire, and as shown in FIG. Is interposed in each of the plate gap spaces S.

[Main part configuration]
2 to 4 show the torsion bar spring 6 interposed in the adjacent driven plate 4 of the wet multi-plate clutch C of the first embodiment. Hereinafter, the configuration of the main part will be described with reference to FIGS.

  The torsion bar spring 6 applies a spring load that separates the adjacent driven plates 4, and as shown in FIG. 2, the torsion bar spring 6 has an annular shape extending over the entire circumference of the plate circumference. As shown in FIGS. 3 and 4, the point of action of the spring load that separates the adjacent driven plates 4 is the opposing spline teeth 4 a of the driven plate 4.

  As shown in FIG. 3, the torsion bar spring 6 is formed of a wire-like wire (metal wire) having a circular cross section made of spring steel or the like. And it is formed in the circumferential direction by the tooth surface of the spline teeth 2a formed on the clutch drum 2, the outer peripheral end surface of the drive plate 3, and the axially opposed surface of the spline tooth portion 4a of the adjacent driven plate 4. It is positioned along the plate gap space S. That is, the torsion bar spring 6 is set in a plate gap space S that does not reach the plate body 4 b of the driven plate 4.

  As shown in FIG. 4, the torsion bar spring 6 includes a torsion wire portion 6a, a first contact wire portion 6b, and a second contact wire portion 6c which are integrally formed. The twisted wire portion 6a is a position that connects adjacent spline teeth 4a of the driven plate 4 in the circumferential direction, and is disposed in the plate gap space S along the circumferential direction. The first contact wire portion 6b is formed by bending in a trapezoidal shape, and applies a spring load to one tooth portion 4a of the spline tooth portions 4a and 4a 'of the driven plates 4 and 4' opposed in the axial direction. The second contact wire portion 6c is formed to be bent in a trapezoidal shape, and applies a spring load to the other tooth portion 4a ′ of the spline tooth portions 4a and 4a ′ of the driven plates 4 and 4 ′ facing in the axial direction. . Of the first contact wire portion 6b bent in a trapezoidal shape, the wire portion on the side corresponding to the upper base becomes the first spring load applying portion SF1. Similarly, of the second contact wire portion 6c bent in a trapezoidal shape, the wire portion on the side corresponding to the upper base becomes the second spring load applying portion SF2. Furthermore, the first contact wire portion 6b and the second contact wire portion 6c bent in a trapezoidal shape are alternately arranged in the circumferential direction with respect to the torsion wire portion 6a along the top of the spline tooth portion 2a of the clutch drum 2. Be placed.

Next, the operation will be described.
The operation of the wet multi-plate clutch C according to the first embodiment will be described by dividing it into “technical background”, “characteristic operation of the wet multi-plate clutch C”, and “other characteristic operations of the wet multi-plate clutch C”.

[Technical background]
In order to reduce friction loss, a technique has been proposed in which an elastic body is provided between the driven plates to ensure a uniform drive plate space. Among the proposed technologies, as shown in FIG. 5, a driven plate having an elastic body function obtained by welding a leaf spring or rubber riveted to a single driven plate is referred to as Comparative Example 1 (for example, JP, 60-78115, A, etc.).

In the case of this comparative example 1, there are problems as listed below.
(a) It is necessary to attach an elastic body to each tooth of the claw-like spline tooth portion, and a large number of manufacturing steps are required.
(b) When the elastic body attached to each spline tooth portion reaches the position of the main body portion of the driven plate as shown by L1 in FIG. 5, the space on the sliding surface is sacrificed.
(c) When an elastic body made of an organic material such as synthetic rubber is used, if the clutch generates heat, it cannot withstand the high heat. In particular, when the clutch is used in a drive system of a hybrid vehicle and is used as a starting clutch that is slip-engaged when the vehicle starts, the clutch heat generation amount is large and cannot be applied.

  Further, as shown in FIGS. 6 and 7, a comparative example 2 is obtained by engaging an annular wave spring having engaging portions at both ends with an engaged portion formed on an adjacent driven plate. (For example, see JP-A-4-307122).

In Comparative Example 2, the problem of manufacturability by itself is solved, but there are problems listed below.
(a) The assembling property at the time of sub-assembly becomes difficult. That is, before assembling the clutch, the driven plate with the drive plate sandwiched between them must be coupled with the elastic body, and the prior assembly performance is poor.
(b) The structure is such that a load is applied by one winding wave spring, and a space is required in the radial direction as indicated by L2 in FIG. For this reason, as shown in FIG. 7, a part of the main body portion of the driven plate is occupied by the wave spring, and the space of the sliding surface is sacrificed.
(c) Since the one-turn wave spring is not a perfect ring, it does not have a separation force enough to return the piston and requires a space for the return spring.

[Characteristic action of wet multi-plate clutch C]
In the first embodiment, the torsion bar spring 6 is interposed in each of the adjacent plate gap spaces S of the driven plate 4. The torsion bar spring 6 has a shape in which the circumference is the entire circumference of the plate circumference, and the point of action of the spring load that separates the adjacent driven plate 4 is the opposing spline tooth portion 4 a of the driven plate 4. It is said.

  That is, the action point of the spring load that separates the adjacent driven plates 4 is a shape that is the spline tooth portion 4 a of the driven plate 4. For this reason, it is not necessary to secure a radial space for applying a spring load to the plate body 4b of the driven plate 4. In other words, when arranging the torsion bar spring 6, as shown by L3 in FIG. A length L3 is sufficient. Therefore, unlike the comparative example 2, the main body of the driven plate is not occupied by the elastic body, and the space of the sliding surface by the clutch facing 3b is not sacrificed as shown in FIG. In other words, it is not necessary to increase the number of plates in order to achieve the design value of the transmission torque capacity, and can be easily applied to an existing wet multi-plate clutch.

  And it is set as the structure which only inserts the torsion bar spring 6 which is an elastic body in the plate clearance space S which the driven plate 4 adjoins. For this reason, unlike Comparative Example 1, it is not necessary to fix the elastic body to each of the driven plates 4 alone. Further, when assembling the unit, the sub-assembly is not required as in the second comparative example, and the operation of assembling the drive plate 3, the driven plate 4, and the torsion bar spring 6 according to a predetermined order may be repeated. For example, the assembly operation can be completed simply by repeating the assembly in the order of driven plate 4 → drive plate 3 → torsion bar spring 6. In this assembling operation, the torsion bar spring 6 is formed in an annular shape, so that the assembled elastic body is held in the plate gap space S without dropping off. Therefore, manufacturability with a single plate is facilitated, and assembly to the unit is facilitated.

  As a result, the problems of Comparative Examples 1 and 2 are solved such that the productivity and assemblability of the plate alone can be facilitated while eliminating the radial space.

[Other characteristic actions of wet multi-plate clutch C]
In the first embodiment, the torsion bar spring 6 is made of a metal wire and positioned along the plate gap space S. Here, the plate gap space S is defined by the tooth surfaces of the spline teeth 2 a formed on the clutch drum 2, the outer peripheral end surface of the drive plate 3, and the axially opposed surfaces of the spline tooth portions 4 a of the adjacent driven plate 4. It is formed in the circumferential direction.
That is, the torsion bar spring 6 is positioned and arranged using the plate gap space S that is not used in the wet multi-plate clutch.
Therefore, by using the unused plate gap space S, the mountability of the torsion bar spring 6 that is an elastic body can be improved.

In the first embodiment, the elastic body is configured as a torsion bar spring 6 that generates a spring load by using a repulsive force when a twist is applied in the direction around the axis of the metal wire.
That is, when the elastic body has a torsion spring configuration, a large reaction force can be generated while being able to be provided in a small space. In other words, the return spring function can be provided by the high separation force of the torsion bar spring 6.
Therefore, by eliminating the return spring from the clutch piston 5, a space for installing the return spring can be eliminated.

In the first embodiment, the torsion bar spring 6 is formed of a wire-like wire having a circular cross section, and a torsion wire portion 6a, a first contact wire portion 6b that applies a spring load to the spline tooth portion 4a, and a spline tooth portion 4a ′. And a second contact wire portion 6c that applies a spring load to the body.
That is, since the torsion bar spring 6 has an integral structure, the torsional reaction force at the torsion wire portion 6a is efficiently converted into spring loads from the first contact wire portion 6b and the second contact wire portion 6c. And this spring load can be provided so that the spline tooth part 4a and spline tooth part 4a 'adjacent to an axial direction may be pulled apart.
Therefore, the torsion bar spring 6 that generates a high separating force by a large spring load can be obtained while using a wire-like wire that can be disposed in a small space.

In the first embodiment, the torsion bar springs 6 are arranged at positions where the adjacent spline teeth 4a of the driven plate 4 are connected in the circumferential direction, and the torsion wire springs 6a are alternately arranged in the circumferential direction with respect to the torsion wire parts 6a. The first contact wire portion 6b and the second contact wire portion 6c are arranged.
That is, the spring load is equally applied at equal intervals from the first contact wire portion 6b and the second contact wire portion 6c arranged at the alternate positions.
Therefore, the circumferential distribution of the separating force with respect to the driven plate 4 adjacent in the axial direction can be equalized, and dragging at the time of release can be stably prevented.

Next, the effect will be described.
In the wet multi-plate clutch C of the first embodiment, the effects listed below can be obtained.

(1) a first member (clutch hub 1) and a second member (clutch drum 2) disposed opposite to the power transmission path;
A plurality of first friction plates (drive plates 3) that are spline-fitted to spline teeth 1a formed on the first member (clutch hub 1);
A plurality of second friction plates (driven plates 4) which are spline-fitted to the spline teeth 2a formed on the second member (clutch drum 2) and disposed between adjacent first friction plates (drive plates 3); ,
A piston member (clutch) that is provided at an end position of a plate group in which the first friction plate (drive plate 3) and the second friction plate (driven plate 4) are alternately arranged, and that provides a fastening force that presses the plate sliding surface. Piston 5),
In a multi-plate friction engagement element (wet multi-plate clutch C) with
An elastic body (torsion bar spring 6) is interposed in each plate gap space adjacent to the second friction plate (driven plate 4),
The elastic body (torsion bar spring 6) has a circumferential length that exceeds half of the circumferential length of the plate, and the point of action of the spring load that separates the adjacent second friction plate (driven plate 4) is the second friction. It was made the shape which is the spline tooth | gear part 4a which the plate (driven plate 4) opposes (FIG. 1).
For this reason, it is possible to facilitate the manufacturability and assemblability of the plate alone while eliminating the radial space.

(2) The elastic body (torsion bar spring 6) is made of a metal wire, and has a tooth surface of spline teeth 2a formed on the second member (clutch drum 2) and the outer periphery of the first friction plate (drive plate 3). Positioning and positioning were performed along the plate gap space S formed in the circumferential direction by the end surface and the axially opposed surface of the spline tooth portion 4a of the adjacent second friction plate (driven plate 4) (FIG. 3).
For this reason, in addition to the effect of (1), the mountability of the elastic body (torsion bar spring 6) can be improved by utilizing the unused plate gap space S.

(3) The elastic body is a torsion bar spring 6 that generates a spring load by using a repulsive force when a twist is applied around the axis of the metal wire (FIG. 4).
For this reason, in addition to the effect of (2), the space for installing the return spring can be eliminated by eliminating the return spring from the piston member (clutch piston 5).

(4) The torsion bar spring 6 is formed of a wire-like wire having a circular cross section, and a torsion wire portion 6a disposed in the plate gap space S along the circumferential direction, and spline teeth portions 4a, 4a opposed in the axial direction. A first contact wire portion 6b that applies a spring load to one tooth portion 4a of 'and a second that applies a spring load to the other tooth portion 4a' of spline tooth portions 4a and 4a 'facing in the axial direction. The contact wire portion 6c is integrally provided (FIG. 4).
For this reason, in addition to the effect of (3), the torsion bar spring 6 that generates a high separation force by a large spring load can be obtained while using a wire-like wire rod that can be arranged in a small space.

(5) The torsion bar spring 6 has a twisted wire portion 6a disposed at a position connecting the adjacent spline teeth 4a of the second friction plate (driven plate 4) in the circumferential direction, and is circumferential with respect to the twisted wire portion 6a. The first contact wire portion 6b and the second contact wire portion 6c are arranged at alternate positions (FIG. 4).
For this reason, in addition to the effect of (4), the circumferential distribution of the separating force with respect to the driven plate 4 adjacent in the axial direction can be equalized, and dragging at the time of release can be stably prevented.

  As mentioned above, although the multi-plate friction fastening element of this invention has been demonstrated based on Example 1, it is not restricted to this Example 1 about a concrete structure, The invention which concerns on each claim of a claim Design changes and additions are permitted without departing from the gist of the present invention.

  In the first embodiment, an example in which the torsion bar spring 6 having a shape in which the acting point of the spring load that separates the adjacent driven plates 4 is the opposing spline tooth portion 4a of the driven plate 4 is used as the elastic body. However, the elastic body is not limited to the torsion bar spring as long as the point of action of the spring load that separates the adjacent second friction plates is a shape that is the spline tooth portion opposed to the second friction plate. .

  In the first embodiment, as the torsion bar spring 6, an example in which the circumference of the torsion bar spring 6 is an annular shape extending over the entire circumference of the plate circumference is shown. However, as the torsion bar spring, for example, as shown in FIG. 8, the torsion bar spring may be one having a circumference exceeding half (180 degrees) of the plate circumference. When the circumferential length of the torsion bar spring is more than half of the circumferential length of the plate, the assembled torsion bar spring is held in the plate gap space without falling off during the assembling operation.

  In the first embodiment, the first contact wire portion 6b and the second contact wire portion 6c bent in a trapezoidal shape are circumferentially arranged with respect to the twisted wire portion 6a along the top of the spline tooth portion 2a of the clutch drum 2. The example which arrange | positions in an alternating position was shown. However, the first contact wire portion and the second contact wire portion bent in a trapezoidal shape may be disposed one after another in the circumferential direction with respect to the torsion wire portion and arranged at alternate positions. It may be an example in which two parts are skipped in the circumferential direction and arranged at alternate positions. Furthermore, it is good also as an example which arrange | positions two contact wire parts by a random pattern in the circumferential direction.

  In Example 1, the example which applies the multi-plate friction fastening element of this invention to the wet multi-plate clutch C was shown. However, the multi-plate friction engagement element of the present invention can also be applied to a dry multi-plate clutch. Furthermore, the present invention can also be applied to a wet multi-plate brake and a dry multi-plate brake that are fixed to a stationary member by fastening. In short, any multi-plate friction fastening element that is fastened by a fastening force applied from the outside, such as a multi-plate clutch or a multi-plate brake that is applied to a drive system of a vehicle, can be applied.

C Wet multi-plate clutch (multi-plate friction fastening element)
1 Clutch hub (first member)
1a Spline teeth 2 Clutch drum (second member)
2a Spline teeth 3 Drive plate (first friction plate)
3a Spline tooth portion 3b Clutch facing 4 Driven plate (second friction plate)
4a Spline tooth part 4b Plate body part 5 Clutch piston (piston member)
6 Torsion bar spring (elastic body)
6a Twisted wire portion 6b First contact wire portion 6c Second contact wire portion

Claims (5)

A first member and a second member disposed opposite to the power transmission path;
A plurality of first friction plates that are spline-fitted to spline teeth formed on the first member;
A plurality of second friction plates that are spline-fitted to spline teeth formed on the second member and disposed between the adjacent first friction plates;
A piston member that is provided at an end position of a plate group in which the first friction plate and the second friction plate are alternately arranged, and that provides a fastening force that presses the plate sliding surface;
In a multi-plate friction fastening element with
An elastic body is interposed in each of the adjacent plate gap spaces of the second friction plate,
The elastic body has a circumferential length that is more than half of the circumferential length of the plate, and the point of action of the spring load that separates the adjacent second friction plates is the spline tooth portion facing the second friction plate. A multi-plate friction fastening element characterized by having a certain shape. The multi-plate friction fastening element according to claim 1,
The elastic body is made of a metal wire, and the spline tooth surface formed on the second member, the outer peripheral end surface of the first friction plate, and the axial direction of the adjacent spline tooth portion of the second friction plate A multi-plate frictional fastening element characterized by being positioned and disposed along a plate gap space formed in a circumferential direction by an opposing surface. The multi-plate friction fastening element according to claim 2,
A multi-plate friction fastening element, wherein the elastic body is a torsion bar spring that generates a spring load by using a repulsive force when a twist is applied in a direction around an axis of a metal wire. The multi-plate friction fastening element according to claim 3,
The torsion bar spring is formed by a wire-like wire having a circular cross section, and a tooth wire portion disposed in the plate gap space along the circumferential direction and one tooth portion among the spline tooth portions facing in the axial direction. A first contact wire portion for applying a spring load to the first contact wire portion and a second contact wire portion for applying a spring load to the other tooth portion of the spline tooth portions facing in the axial direction are integrally provided. Multi-plate friction fastening element. The multi-plate friction fastening element according to claim 4,
The torsion bar spring has the torsion wire portion arranged at a position that connects adjacent spline teeth portions of the second friction plate in the circumferential direction, and the first contact at an alternating position in the circumferential direction with respect to the torsion wire portion. A multi-plate friction fastening element, wherein a wire portion and the second contact wire portion are disposed.