Electric friction clutch device

Abstract

To provide a structure which can accurately adjust a transmission torque capacity and reduce a manufacturing cost.SOLUTION: A cam device 5 includes: a drive cam 36 having a cam face 39 provided on a lateral face on one side in an axial direction and a cam-side stopper face 40 directed in a circumferential direction, the drive cam being supported to a fixed part which does not rotate during use in a rotatable and axially non-displaceable manner; a holder 37 having a holder-side stopper face 53 in contact with the cam-side stopper face 40 in a state where a distance from the drive cam 36 is the most shortened, the holder being supported to the fixed part in an axially displaceable and non-rotatable manner; and a plurality of rotors 38 having a rolling face 61 that rolls and contacts the cam face 39, and held by the holder 37.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present disclosure relates to an electric friction clutch device that switches between a connected mode in which a first member and a second member rotate integrally, and a disconnected mode in which the first member and the second member rotate relative to each other. [Background technology]

[0002] In rotating machinery such as automobiles and machine tools, a transmission is provided between a power source, such as an engine or an electric motor, and a driven object to efficiently utilize the output of the power source. When a gear-type transmission with multiple stages is used as such a transmission, a clutch device is installed between the power source and the transmission to switch between a locked state in which the output torque of the power source can be transmitted to the transmission and an unlocked state in which it cannot be transmitted. Examples of such clutch devices include a friction clutch that transmits power through friction between a pair of opposing friction surfaces, and a dog clutch that transmits power through meshing pawls.

[0003] The friction clutch can switch between a connected mode in which torque can be transmitted and a disconnected mode in which torque cannot be transmitted, regardless of the phase difference or rotational speed difference between a pair of opposing engaging members.

[0004] 27 and 28 show a clutch device 100 described in WO 2008 / 096438. The clutch device 100 is disposed between an input member (rear wheel output shaft) 101 and an output member (sprocket) 102, and switches between a connected mode in which torque is transmitted between the input member 101 and the output member 102, and a disconnected mode in which torque is not transmitted between the input member 101 and the output member 102. The clutch device 100 includes a first member 103, a second member 104, a friction engagement unit 105, a cam device 106, an electric actuator 107, a pressing member 108, a rolling bearing 109, an elastic member 110, and a load detection unit 111.

[0005] The first member 103 is coupled and fixed to the input member 101 and rotates integrally with the input member 101. The first member 103 has a small-diameter cylindrical portion 103a fitted and fixed to the outside of the input member 101, a side plate portion 103b bent radially outward from an end portion on one axial side (left side in FIG. 27) of the small-diameter cylindrical portion 103a, and a large-diameter cylindrical portion 103c protruding toward the other axial side from a radially intermediate portion of a side surface on the other axial side (right side in FIG. 27) of the side plate portion 103b. That is, the first member 103 has a substantially F-shaped cross section.

[0006] The second member 104 is coupled and fixed to the output member 102, and rotates integrally with the output member 102. The second member 104 has a circular ring portion 104a that is fitted and fixed to the outside of the output member 102, and a cylindrical portion 104b that is bent from the radially outer end of the circular ring portion 104a toward the other axial side.

[0007] The friction engagement portion 105 includes a plurality of first friction plates 105a and a plurality of second friction plates 105b stacked alternately in the axial direction. Each first friction plate 105a is fitted externally to the large-diameter cylindrical portion 103c of the first member 103 so as to be displaceable in the axial direction but not to rotate relative thereto. Each second friction plate 105b is fitted internally to the cylindrical portion 104b of the second member so as to be displaceable in the axial direction but not to rotate relative thereto.

[0008] The cam device 106 includes a drive cam 106a, a cam plate 106b, and a plurality of balls 106c.

[0009] The drive cam 106a has a drive-side cam surface 106a1 on its other axial side and a gear portion 106a2 on its outer circumferential surface. The drive cam 106a is disposed around the input member 101 so as to be capable of relative rotation with respect to the input member 101 and of axial displacement.

[0010] Cam plate 106b has a fixed-side cam surface 106b1 on one axial side surface. Cam plate 106b is disposed around input member 101 so as to be capable of rotating relative to input member 101 but not capable of moving in the axial direction.

[0011] Each ball 106c is held between a driving side cam surface 106a1 and a fixed side cam surface 106b1 in a rollable manner.

[0012] The electric actuator 107 rotates and drives the drive cam 106a of the cam device 106. The electric actuator 107 has an electric motor 107a and a reducer 107b that increases the output torque of the electric motor 107a and transmits it to the drive cam 106a. For this purpose, an output gear 107b1 of the reducer 107b is meshed with a gear portion 106a2 provided on the outer circumferential surface of the drive cam 106a.

[0013] The pressing member 108 is disposed opposite to the other axial side of the friction plate that is located furthest on the other axial side among the plurality of first friction plates 105a and second friction plates 105b, and is supported so as to be movable toward and away from the friction plate located furthest on the other axial side. The pressing member 108 is fitted around the periphery of the input member 101 so as to be movable in the axial direction relative to the input member 101.

[0014] The rolling bearing 109 is disposed between the driving cam 106a and the pressing member 108.

[0015] The elastic member 110 is sandwiched between the first member 103 and the pressing member 108 in an elastically compressed state, and elastically biases the pressing member 108 toward the other axial side. The elastic member 110 is made of a compression coil spring.

[0016] When switching the clutch device 100 to the connection mode, the electric actuator 107 rotates the drive cam 106a, and the ball 106c is positioned between the tip surface of the convex portion of the drive-side cam surface 106a1 and the tip surface of the convex portion of the fixed-side cam surface 106b1, thereby widening the gap between the drive cam 106a and the cam plate 106b and pressing the pressing member 108 toward one axial side against the elastic force of the elastic member 110. As a result, the first friction plate 105a and the second friction plate 105b are pressed against each other, thereby connecting the frictional engagement portion 105 and allowing the first member 103 and the second member 104 to rotate integrally.

[0017] When the clutch device 100 is switched to the disengagement mode, the electric actuator 107 rotates the drive cam 106a, and the ball 106c is positioned between the bottom of the recess in the drive-side cam surface 106a1 and the bottom of the recess in the fixed-side cam surface 106b1. The elastic force of the elastic member 110, which tries to return to its original shape, presses the pressing member 108 toward the other axial direction, thereby reducing the gap between the drive cam 106a and the cam plate 106b. As a result, the force pressing the first friction plate 105a and the second friction plate 105b against each other is released, the frictional engagement portion 105 is disengaged, and the first member 103 and the second member 104 begin to rotate relative to each other.

[0018] The load detection unit 111 detects a load in the direction in which the cam plate 106b rotates in a direction in which the gap between the cam plate 106b and the drive cam 106a increases. The load detection unit 111 includes a hydraulic cylinder and a pressure sensor.

[0019] The control device that controls the clutch device 100 controls the electric motor 107 a based on the load detected by the load detection unit 111 .

[0020] Therefore, according to the clutch device 100 described in WO 2008 / 096438, it is possible to accurately adjust the transmission torque capacity, which is the amount of torque that can be transmitted between the first friction plate 105a and the second friction plate 105b without causing slippage. This prevents slippage between the first friction plate 105a and the second friction plate 105b due to a shortage of the transmission torque capacity of the friction engagement portion 105 relative to the torque to be transmitted between the input member 101 and the output member 102, while also preventing excessive loads from being applied to each part due to an unnecessary increase in the amount of rotation of the drive cam 106a by the electric actuator 107. [Prior art documents] [Patent documents]

[0021] [Patent Document 1] International Publication No. 2008 / 096438 Summary of the Invention [Problem to be solved by the invention]

[0022] The clutch device described in WO 2008 / 096438 is provided with a load detection unit 111 that has a hydraulic cylinder and a pressure sensor, which increases manufacturing costs.

[0023] An object of the present disclosure is to realize a structure of an electric friction clutch that can adjust transmission torque capacity with high precision and can reduce manufacturing costs. [Means for solving the problem]

[0024] An electric friction clutch device according to a first aspect of the present disclosure includes a first member, a second member, a friction engagement portion, a cam device, an electric actuator, a pressing member, a rolling bearing, and an elastic member.

[0025] The second member is supported coaxially with the first member and rotatable relative to the first member.

[0026] The friction engagement portion has at least one, and preferably a plurality of, first and second friction plates that are supported to allow relative displacement in the axial direction.

[0027] The cam device includes a drive cam, a holder, and a plurality of rolling elements.

[0028] The drive cam has a cam surface provided on one side in the axial direction and a cam side stopper surface facing in the circumferential direction, and is supported so that it can rotate relative to a fixed part that does not rotate even when in use, but cannot move in the axial direction.

[0029] The holder has a holder-side stopper surface that abuts against the cam-side stopper surface when the distance between the holder and the drive cam is at its shortest, i.e., when the axial dimension of the cam device is at its smallest, and is supported so as to be able to move axially relative to the fixed member but not to rotate.

[0030] The rolling element has a rolling surface that comes into rolling contact with the cam surface, and is held by the holder.

[0031] The electric actuator rotates the drive cam.

[0032] The pressing member is disposed opposite the side surface on the other axial side of the friction plate that is located furthest on the other axial side among the first friction plate and the second friction plate, and is supported so as to be movable toward and away from the friction plate located furthest on the other axial side in the axial direction.

[0033] The rolling bearing is disposed between the holder and the pressing member.

[0034] The elastic member elastically biases the pressing member toward the other axial side.

[0035] The electric friction clutch device of the first aspect of the present disclosure switches to a connection mode in which the first member and the second member rotate as a unit by displacing the holder in a direction in which the distance between the holder and the drive cam increases, i.e., in a direction in which the axial dimension of the cam device increases, by rotating the drive cam using the electric actuator, and by pressing the first friction plate and the second friction plate against each other, and by displacing the holder in a direction in which the distance between the holder and the drive cam decreases, i.e., in a direction in which the axial dimension of the cam device decreases, by releasing the force pressing the first friction plate and the second friction plate against each other, and by displacing the holder in a direction in which the distance between the holder and the drive cam decreases, i.e., in a direction in which the axial dimension of the cam device decreases, the force pressing the first friction plate and the second friction plate against each other is released, and the electric friction clutch device switches to a disconnection mode in which the first member and the second member rotate relative to each other.

[0036] In a second aspect of the electric friction clutch device of the present disclosure, in the electric friction clutch device of the first aspect of the present disclosure, a plurality of reference surfaces formed by flat surfaces perpendicular to the central axis of the drive cam and a plurality of convex portions protruding toward one axial side from the reference surfaces are alternately arranged in the circumferential direction. In this case, the cam-side stopper surface is provided on a side surface of at least one of the plurality of convex portions that faces the rotation direction of the drive cam when the gap between the drive cam and the holder is reduced.

[0037] In the electric friction clutch device of the third aspect of the present disclosure, in the electric friction clutch device of the first or second aspect of the present disclosure, the holder has a plurality of holding portions arranged at multiple locations in the circumferential direction and holding the multiple rolling elements rotatably, and a plurality of connecting portions connecting two circumferentially adjacent holding portions among the multiple holding portions.

[0038] In an electric friction clutch device of a fourth aspect of the present disclosure, in the electric friction clutch device of the third aspect of the present disclosure, each of the plurality of retaining portions has a portion that protrudes in the other axial direction beyond the side surface on the other axial side of the plurality of connecting portions. In this case, the holder-side stopper surface is provided on a portion of at least one of the plurality of retaining portions that protrudes in the other axial direction beyond the side surface on the other axial side of the plurality of connecting portions, and is located circumferentially opposite the cam-side stopper surface.

[0039] In the electric friction clutch device of a fifth aspect of the present disclosure, in the electric friction clutch device of either the third or fourth aspect of the present disclosure, the fixed portion is provided with a support member at one axial end having at least one engagement notch that engages with a part of the holder to allow relative axial displacement but not allow relative circumferential displacement, and including a fixed cylindrical portion that is fitted into the holder to allow relative axial displacement.

[0040] In the electric friction clutch device of the sixth aspect of the present disclosure, in the electric friction clutch device of the fifth aspect of the present disclosure, the holder has at least one engaging protrusion that protrudes radially inward from the radial inner surface of at least one of the plurality of retaining portions or the radial inner surface of at least one of the plurality of connecting portions, and engages with the at least one engaging notch portion to enable relative axial displacement but not to enable relative circumferential displacement.

[0041] In a seventh aspect of the electric friction clutch device of the present disclosure, in the electric friction clutch device of the fifth aspect of the present disclosure, the at least one engagement notch is configured by a plurality of engagement notches, and in this case, the plurality of engagement notches engage with the plurality of holding portions.

[0042] In an electric friction clutch device of an eighth aspect of the present disclosure, in an electric friction clutch device of any of the third to seventh aspects of the present disclosure, when the holder is viewed from the axial direction, the radially outer surfaces of the plurality of connecting portions are located radially inward of the circumscribing circle of the plurality of retaining portions. [Effects of the Invention]

[0043] According to the electric friction clutch device of the present disclosure, it is possible to adjust the transmission torque capacity with high precision and reduce manufacturing costs. [Brief explanation of the drawings]

[0044] [Figure 1] FIG. 1 is an end view of an electric friction clutch device according to a first example of an embodiment of the present disclosure, as viewed from one axial side. [Figure 2] FIG. 2 is an end view of the electric friction clutch device of the first example, as viewed from the other axial side. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. 1, with the second member omitted. [Figure 4] FIG. 4 is an exploded perspective view showing the electric friction clutch device of the first example. [Figure 5] FIG. 5 is a perspective view of the electric friction clutch device of the first example, seen from one axial side, with the second member omitted. [Figure 6] FIG. 6 is a perspective view of the electric friction clutch device of the first example, seen from the other axial side, with the second member omitted. [Figure 7] FIG. 7 is a perspective view showing the first member. [Figure 8] FIG. 8 is a cross-sectional view showing the first member. [Figure 9] FIG. 9 is a perspective view showing the support member. [Figure 10] FIG. 10 is a side view showing the cam device. [Figure 11] Figure 11 is a diagram equivalent to an enlarged view of the central portion of Figure 10, in which (A) is a diagram showing the state in which the cam side stopper surface and the holder side stopper surface are in contact, (B) is a diagram showing the state in which the rolling body is positioned on the reference surface, and (C) is a diagram showing the state in which the rolling body has climbed onto the inclined surface portion. [Figure 12] FIG. 12 is a perspective view showing the drive cam and the worm. [Figure 13] FIG. 13 is an end view of the holder and rolling elements assembled together, as viewed from the other axial side. [Figure 14] FIG. 14 is a cross-sectional view taken along the line BB in FIG. [Figure 15] FIG. 15 is an exploded perspective view showing the assembly of the rolling elements to the holder. [Figure 16] FIG. 16 is a diagram showing a schematic diagram of the relationship between the rotation angle of the drive cam and the transmission torque capacity of the friction engagement portion. [Figure 17] FIG. 17 is a cross-sectional view of an electric friction clutch device according to a second example of an embodiment of the present disclosure. [Figure 18] FIG. 18 is an exploded perspective view showing a holder, rolling elements, and support members that constitute an electric friction clutch device according to a third embodiment of the present disclosure. [Figure 19] FIG. 19 is a perspective view showing the third example in a state where the rolling elements are assembled to the holder. [Figure 20] FIG. 20 is a view similar to FIG. 13 for the third example. [Figure 21] FIG. 21 is an end view of the support member of the third example, as viewed from one axial side. [Figure 22] Figure 22 is a diagram showing a holder constituting an electric friction clutch device of a fourth example of an embodiment of the present disclosure with rolling elements assembled thereto, where (A) is an oblique view seen from the other axial side, and (B) is an oblique view seen from one axial side. [Figure 23] FIG. 23 is an end view of the fourth example, seen from the other axial side, showing the state in which the rolling elements are assembled to the holder. [Figure 24] FIG. 24 is an end view of the holder in the fourth example, as viewed from the other axial side. [Figure 25] FIG. 25 is a side view showing a holder, rolling elements, and support members that constitute an electric friction clutch according to a fifth example of an embodiment of the present disclosure. [Figure 26] FIG. 26 is an exploded perspective view of the holder, the rolling elements, and the support member in the fifth example. [Figure 27] FIG. 27 is a cross-sectional view showing an example of a clutch device having a conventional structure. [Figure 28] FIG. 28 is an end view that schematically shows a drive cam, a cam plate, a reducer, and a load detector that constitute a clutch device of a conventional structure. DETAILED DESCRIPTION OF THE INVENTION

[0045] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to Figures 1 to 16. An electric friction clutch device 1 of this example includes a first member 2, a second member 3, a friction engagement portion 4, a cam device 5, an electric actuator 6, a pressing member 7, a rolling bearing 8, and an elastic member 9.

[0046] The electric friction clutch device 1 is disposed, for example, in a portion of the drive system of an automobile between a drive source such as an electric motor or an engine and a transmission, or between the transmission and a differential. However, the electric friction clutch device of the present disclosure can be disposed between a pair of rotating members or between a rotating member and a fixed member in various mechanical devices, regardless of the drive system of the automobile.

[0047] In the following description, unless otherwise specified, the axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction of the first member 2. One axial side refers to the left side in Fig. 3, and the other axial side refers to the right side in Fig. 3.

[0048] The first member 2 is rotatably supported by a support member 10 that forms a fixed portion that does not rotate even during use. The first member 2 is connected to a first rotating member (not shown) such as the output shaft of a drive source or the output shaft of a transmission so as to be able to transmit torque.

[0049] In this example, the support member 10 includes a fixed cylindrical portion 11 and a flange portion 12 bent radially outward from the other axial end of the fixed cylindrical portion 11.

[0050] The fixed cylinder portion 11 has a male spline portion 13 on the outer peripheral surface of one end portion in the axial direction.

[0051] The flange portion 12 has a plurality of through holes 14a, 14b penetrating in the axial direction at a plurality of positions in the circumferential direction. In this example, of the plurality of through holes 14a, 14b, the inner diameter of one through hole 14a is larger than the inner diameter of the remaining through hole 14b.

[0052] The support member 10 is positioned relative to the fixed part by inserting a pin portion protruding from a fixed part such as a housing into one of the through holes 14a, and is then supported and fixed to the fixed part by a bolt inserted through the remaining through hole 14b, so that it does not rotate or displace even during use.

[0053] In this example, the first member 2 includes a flange member 15 and a shaft body 16, as shown in FIGS.

[0054] The flange member 15 has a first cylindrical portion 17 and a circular ring portion 18 bent radially inward from one axial end of the first cylindrical portion 17. In this example, the flange member 15 is made by pressing a metal plate having sufficient strength and rigidity, such as a steel plate, and then nitriding the surface.

[0055] The first cylindrical portion 17 has an inner diameter side uneven portion 19 on its outer peripheral surface, in which recesses and protrusions are alternately arranged in the circumferential direction. The first cylindrical portion 17 also has outer side oil passage holes 79 that penetrate the first cylindrical portion 17 in the radial direction, at multiple locations in the circumferential direction.

[0056] Shaft body 16 is joined and fixed to the inner circumferential surface of circular ring portion 18 of flange member 15. Shaft body 16 has a substantially cylindrical tubular portion 20, and a hollow circular plate-like outward flange portion 21 that bends radially outward from one axial end of tubular portion 20. Shaft body 16 is made by forging a hard metal material such as medium carbon steel, and then nitriding the surface.

[0057] The cylindrical portion 20 has a locking groove 22 formed around the entire circumference on the outer peripheral surface of the other axial side portion, and a female spline portion 23 formed on the inner peripheral surface of the other axial side end portion. The cylindrical portion 20 also has inner-side oil holes 80 that penetrate radially at multiple locations around the circumference of the one axial side portion.

[0058] First member 2 is constructed by fitting the outer peripheral surface of outward flange portion 21 of shaft body 16 into the inner peripheral surface of circular ring portion 18 of flange member 15, and then joining and fixing flange member 15 and shaft body 16 together by welding. First member 2 is connected to the first rotating member so as to be able to transmit torque by spline-engaging a male spline portion provided on the first rotating member with a female spline portion 23.

[0059] In this example, the first member 2 is rotatably supported relative to the support member 10 by a radial rolling bearing 24.

[0060] The radial rolling bearing 24 includes an inner ring 25, an outer ring 26, and a plurality of rolling elements 27 disposed between the inner ring 25 and the outer ring 26 so as to be freely rollable.

[0061] The inner ring 25 is fitted onto the other axial side portion of the cylindrical portion 20 and is prevented from being displaced toward the other axial side by a retaining ring 28 engaged with the engaging groove 22 .

[0062] The outer ring 26 is fitted into the other axial side portion of the fixed cylindrical portion 11 and is provided on the inner surface of the axial middle portion of the fixed cylindrical portion 11, and displacement to one axial side is prevented by a step surface 29 facing the other axial side.

[0063] The radial rolling bearing 24 in this example is a single-row angular contact ball bearing that uses balls as rolling elements 27 and has a contact angle. However, the radial rolling bearing for rotatably supporting the first member relative to the fixed member is not particularly limited as long as it can support radial and thrust loads, and can also be a single-row deep groove ball bearing or a tapered roller bearing.

[0064] The second member 3 is supported coaxially with the first member 2 and capable of relative rotation with respect to the first member 2. The second member 3 is connected to a second rotating member (not shown) such as an input shaft of a transmission or an input shaft of a differential device so as to be capable of transmitting torque. In this example, the second member 3 has a second tubular portion 30.

[0065] The second cylindrical portion 30 has an outer diameter side concave-convex portion 31 on its inner circumferential surface, in which concave portions and convex portions are alternately arranged in the circumferential direction.

[0066] The friction engagement portion 4 has at least one, and preferably multiple, first friction plates 32 and second friction plates 33 that are supported so as to be capable of relative axial displacement. In this example, the friction engagement portion 4 is formed by alternately stacking five first friction plates 32 and five second friction plates 33.

[0067] Each of the first friction plates 32 is configured in a substantially hollow circular plate shape. By engaging the outer diameter side uneven portion provided on the inner circumferential surface of each of the first friction plates 32 with the inner diameter side uneven portion 19 of the first member 2, the first friction plates 32 are supported so as to be able to move in the axial direction with respect to the first cylindrical portion 17 but not to rotate relative to the first cylindrical portion 17.

[0068] Each second friction plate 33 is configured in a substantially hollow circular plate shape. By engaging an inner diameter side uneven portion provided on the outer circumferential surface of each second friction plate 33 with an outer diameter side uneven portion 31 of the second member 3, the second friction plate 33 is supported so as to be able to move in the axial direction with respect to the second cylindrical portion 30 but not to rotate relative to the second cylindrical portion 30.

[0069] The side surface on one axial direction of the first friction plate 32, which is located furthest to one axial direction among the five second friction plates 33, abuts or closely faces the side surface on the other axial direction of a spacer 34 fitted onto the one axial side portion of the first cylindrical portion 17. The spacer 34 is prevented from displacing to one axial side by a retaining ring 35 engaged with the outer peripheral surface of the one axial side portion of the first cylindrical portion 17.

[0070] The frictional engagement portion 4 may include a return spring that elastically biases the first friction plate 32 and the second friction plate 33 in a direction that separates them from each other.

[0071] The cam device 5 includes a drive cam 36, a holder 37, and a plurality of rolling elements 38 (three in the illustrated example).

[0072] The drive cam 36 has, on one axial side thereof, a cam surface 39 which is an uneven surface in the circumferential direction, and a cam-side stopper surface 40 facing in the circumferential direction. The cam-side stopper surface 40 faces the rotation direction of the drive cam 36 when the gap between the drive cam 36 and the holder 37 is reduced, i.e., when the axial dimension L (see FIG. 10) of the cam device 5 is reduced. The drive cam 36 is supported so as to be rotatable relative to a fixed portion which does not rotate even during use, but so as not to be displaceable in the axial direction.

[0073] In this example, the drive cam 36 has a main body 41 formed in a hollow circular shape, and a substantially sector-shaped protrusion 42 protruding radially outward from one circumferential position of the main body 41.

[0074] The cam surface 39 is provided on one axial side surface of the main body portion 41 .

[0075] 12, cam surface 39 is formed by circumferentially arranging a plurality of reference surfaces 43, each made of a flat surface perpendicular to the central axis of drive cam 36, and a plurality of protrusions 44 protruding from reference surfaces 43 to one axial side, alternately. Cam-side stopper surface 40 is provided on the circumferential side surface of at least one of the plurality of protrusions 44, facing the rotation direction when axial dimension L of cam device 5 is reduced.

[0076] In this example, the cam surface 39 has three reference surfaces 43 and three protrusions 44, and the cam side stopper surfaces 40 are provided on the circumferential side surfaces of all the protrusions 44 facing the rotation direction when reducing the axial dimension L of the cam device 5.

[0077] Each reference surface 43 has a fan-shaped surface shape when viewed from one axial side.

[0078] Each protrusion 44 has a flat surface portion 45 on its tip surface, a cam side stopper surface 40 on one circumferential side surface facing the rotation direction when reducing the axial dimension L of the cam device 5, and an inclined surface portion 46 on the other circumferential side surface facing the rotation direction when increasing the axial dimension L of the cam device 5.

[0079] The flat surface portion 45 is formed by a flat surface that is perpendicular to the central axis of the drive cam 36, and has a fan-shaped surface shape when viewed from one axial side.

[0080] The cam side stopper surface 40 is formed of a flat surface perpendicular to the flat surface portion 45.

[0081] The inclined surface portion 46 is inclined in a direction toward one axial side as it goes toward the rear side with respect to the rotation direction when the axial dimension L of the cam device 5 is increased, and connects the reference surface 43 and the flat surface portion 45.

[0082] In this example, the inclined surface portion 46 is configured by a plane whose inclination angle with respect to an imaginary plane perpendicular to the central axis of the cam device 5 is constant in the circumferential direction. However, the inclined surface portion 46 may also be configured by a curved surface or a composite surface made up of a plurality of flat and / or curved surfaces.

[0083] That is, cam surface 39 is configured by arranging reference surface 43, inclined surface portion 46, flat surface portion 45, and cam-side stopper surface 40 in this order multiple times (three times in the illustrated example) in the circumferential direction. Of cam surface 39, flat surface portion 45 is located closest to one axial side, and reference surface 43 is located closest to the other axial side.

[0084] The protrusion 42 has a gear portion 47 on its radially outer surface. In this example, the gear portion 47 is configured as a helical gear. However, the gear portion 47 may also be configured as a spur gear.

[0085] The drive cam 36 is supported by a radial rolling bearing 48 so as to be rotatable relative to the support member 10 but so as not to be displaced in the axial direction. The radial rolling bearing 48 is disposed between the inner peripheral surface of the main body 41 and the outer peripheral surface of the other axial end of the fixed cylinder 11.

[0086] The radial rolling bearing 48 includes an inner ring 49, an outer ring 50, and a plurality of rolling elements 51 disposed between the inner ring 49 and the outer ring 50 so as to be freely rollable.

[0087] The inner ring 49 is fitted onto the end portion on the other axial side of the fixed cylindrical portion 11, and the side surface on the other axial side abuts against the side surface on one axial side of the flange portion 12.

[0088] The outer ring 50 is fitted into the main body 41, and one axial side of the outer ring 50 abuts against a stepped surface 52 provided on the inner circumferential surface of the main body 41 and facing the other axial side.

[0089] Radial rolling bearing 48 uses balls as rolling elements 51 and is configured as a single-row angular contact ball bearing with a contact angle. However, radial rolling bearing 48 for rotatably supporting drive cam 36 relative to support member 10 is not particularly limited as long as it can support radial loads and thrust loads, and can also be configured as a single-row deep groove ball bearing, tapered roller bearing, etc.

[0090] Holder 37 is supported so as to be unable to rotate but movable in the axial direction relative to support member 10. Holder 37 has holder-side stopper surface 53 that abuts against cam-side stopper surface 40 when the distance between holder 37 and drive cam 36 is at its shortest, i.e., when axial dimension L of cam device 5 is at its smallest.

[0091] 13 to 15, the holder 37 includes a plurality of holding portions 54 arranged at a plurality of locations in the circumferential direction and rotatably holding a plurality of rolling elements 38, and a plurality of connecting portions 55 connecting two of the plurality of holding portions 54 that are adjacent in the circumferential direction. Each of the plurality of holding portions 54 has a portion that protrudes in the other axial direction beyond the side surface on the other axial side of the plurality of connecting portions 55. The holder-side stopper surface 53 is a portion that protrudes in the other axial direction from the side surface on the other axial side of the plurality of connecting portions 55 of at least one of the plurality of holding portions 54, and is provided at a portion that faces the cam-side stopper surface 40 in the circumferential direction.

[0092] Each of the holding portions 54 has a generally rectangular cylindrical shape. Specifically, the holding portion 54 has a pair of support plate portions 56a and 56b and a pair of connecting plate portions 57a and 57b.

[0093] The pair of support plates 56a, 56b are each configured as a substantially rectangular flat plate and are arranged parallel to each other while being spaced apart in the radial direction. Support plates 56a, 56b each have support holes 58a, 58b. Support holes 58a, 58b each penetrate support plates 56a, 56b in the radial direction and are formed as circular holes that are coaxial with each other.

[0094] Of the pair of support plate portions 56a, 56b, the radially inner support plate portion 56a has a locking hole 59 that passes through in the axial direction at a portion of the support plate portion 56a that is off the circumferential center position.

[0095] Each of the pair of connecting plates 57a, 57b is configured in a substantially rectangular flat plate shape. The pair of connecting plates 57a, 57b connects both circumferential ends of the pair of support plates 56a, 56b. The outer circumferential side surfaces of the pair of connecting plates 57a, 57b, specifically, the one circumferential side surface of the connecting plate 57a on one circumferential side and the other circumferential side surface of the connecting plate 57b on the other circumferential side, are parallel to each other and are configured as flat surfaces perpendicular to an imaginary plane perpendicular to the central axis of the holder 37.

[0096] Each of the connecting portions 55 connects two of the plurality of holding portions 54 that are adjacent to each other in the circumferential direction.

[0097] In this example, each connecting portion 55 is formed of a flat plate having a generally fan-shaped end face when viewed in the axial direction. One circumferential end of each connecting portion 55 is connected to one axial end of a side surface on the other circumferential side of a connecting plate portion 57b on the other circumferential side of one of the two circumferentially adjacent holding portions 54, and the other circumferential end of each connecting portion 55 is connected to one axial end of a side surface on one circumferential side of a connecting plate portion 57a on the one circumferential side of the other of the two circumferentially adjacent holding portions 54. This gives the holder 37 a generally annular shape as a whole.

[0098] Each of the connecting portions 55 also has a female spline portion 60 on its radially inner surface.

[0099] The holder 37 is supported so as to be unable to rotate relative to the support member 10 but to be able to move axially by spline-engaging the female spline portion 60 with the male spline portion 13 of the support member 10, allowing relative axial movement.

[0100] In addition, in this example, the holder side stopper surface 53 is provided on the portion of the side surface on the other circumferential side of the connecting plate portion 57b on the other circumferential side of all the holding portions 54 that protrudes in the other axial direction from the side surface on the other axial side of the connecting portion 55.

[0101] Each rolling body 38 has a rolling surface 61 on its outer surface that is in rolling contact with the cam surface 39, and is held in the holder 37 so as to be able to freely rotate (spin) around its own central axis (spinning axis) C, which is arranged in a radial direction around the central axis of the holder 37.

[0102] In this example, each rolling element 38 is configured as a cylindrical roller and is rotatably supported relative to the holder 37 by a columnar support shaft 62 and a plurality of rollers 63. Specifically, the rolling elements 38 are arranged around an axial middle portion of the support shaft 62 (a middle portion of the support shaft 62 in the radial direction about the central axis of the holder 37), and each roller 63 is arranged to roll freely between the outer circumferential surface of the support shaft 62 and the inner circumferential surface of the rolling elements 38. Furthermore, both axial end portions of the support shaft 62, i.e., both radial end portions of the support shaft 62 about the central axis of the holder 37, are fitted into the support holes 58a, 58b of the support plate portions 56a, 56b.

[0103] Furthermore, in this example, the cam device 5 is provided with a retaining member 64 that prevents the support shaft 62 from being displaced in the axial direction of the support shaft 62 relative to the holder 37 (in the radial direction about the central axis of the holder 37). In this example, the retaining member 64 is configured as a cylindrical pin. Both axial ends of the retaining member 64 are press-fitted into the locking holes 59, and the axial middle portion of the retaining member 64 is disposed inside a locking groove 73 that is formed around the entire circumference of the support shaft 62 on the inner side in the radial direction of the holder 37. This prevents the support shaft 62 from falling off the holder 37.

[0104] In the cam device 5, as the drive cam 36 rotates, the amount by which the rolling element 38 rides up from the reference surface 43 of the cam surface 39 increases or decreases, thereby displacing the holder 37 in the axial direction.

[0105] There are no particular limitations on the materials that make up the drive cam 36, holder 37, and rolling elements 38, but for example, the drive cam 36 and / or holder 37 can be made as a single unit from sintered metal, which allows drive cams 36 and / or holders 37 with complex shapes to be manufactured at low cost.

[0106] The electric actuator 6 rotates the drive cam 36. In this example, the electric actuator 6 includes an electric motor (not shown) and a reducer 65. The reducer 65 is configured by meshing a worm 66, which is rotated by the electric motor, with the gear portion 47 of the drive cam 36.

[0107] The pressing member 7 faces the friction plate that is located furthest on the other axial side among the first friction plate 32 and the second friction plate 33, i.e., the first friction plate 32 that is furthest on the other axial side in this example, and is arranged so that it can move toward and away from the first friction plate 32 that is furthest on the other axial side in the axial direction.

[0108] In this example, the pressing member 7 is formed by bending a metal plate having sufficient strength and rigidity, such as a steel plate, into a generally crank-shaped cross section. Specifically, the pressing member 7 has a hollow circular plate-like side plate portion 67, a cylindrical portion 68 bent from the radially outer end of the side plate portion 67 toward the other axial side, and a pressing plate portion 69 bent from the axially outer end of the cylindrical portion 68 toward the radially outer side.

[0109] Side plate portion 67 is fitted onto first member 2 so as to allow relative displacement in the axial direction. Specifically, side plate portion 67 is fitted onto one axial side portion of tubular portion 20 of shaft body 16 without rattle and so as to allow relative displacement in the axial direction. In this way, pressing member 7 is supported onto first member 2 so as to allow relative displacement in the axial direction.

[0110] The pressing plate portion 69 has a generally S-shaped cross section, and one axial side surface of the radially outer portion faces the other axial side surface of the first friction plate 32 closest to the other axial side.

[0111] The rolling bearing 8 is disposed between the holder 37 and the pressing member 7 .

[0112] In this example, the rolling bearing 8 is a single-row angular contact ball bearing capable of supporting radial and thrust loads. That is, the rolling bearing 8 includes an outer ring 70, an inner ring 71, and balls 72 arranged to roll freely between the outer ring 70 and the inner ring 71. The rolling bearing 8 is sandwiched between a side surface on one axial side of the holder 37 and a side surface on the other axial side of the side plate portion 67 of the pressing member 7. In other words, the side surface on one axial side of the outer ring 70 abuts against the side surface on the other axial side of the side plate portion 67, and the side surface on the other axial side of the inner ring 71 abuts against the side surface on one axial side of the holder 37.

[0113] When implementing the present disclosure, the rolling bearing disposed between the holder and the pressing member is not limited to an angular contact ball bearing, and various rolling bearings can be used as long as they can support thrust loads. For example, the rolling bearing can be a deep groove ball bearing capable of supporting radial loads and thrust loads, or a thrust needle bearing or thrust ball bearing capable of supporting only thrust loads.

[0114] The elastic member 9 elastically biases the pressing member 7 toward the other axial side. For this reason, the elastic member 9 is sandwiched in an elastically compressed state between the pressing member 7 and the first member 2. As a result, regardless of the axial dimension of the cam device 5, a preload is applied to the rolling elements 38 of the cam device 5 and the rolling bearings 8, 24, 48, preventing harmful slippage at the rolling contact portions.

[0115] In this example, the elastic member 9 is made up of one disc spring, but the elastic member may also be made up of a plurality of disc springs.

[0116] In the electric friction clutch device 1 of this example, the elastic member 9, a portion of the pressing member 7, and the rolling bearing 8 are arranged radially inside the first cylindrical portion 17 of the first member 2, regardless of the axial dimension of the cam device 5.

[0117] In this example, even when the rolling element 38 is positioned on the reference plane 43 and the axial dimension of the cam device 5 is at its smallest, the elastic member 9, the one axial side portion and side plate portion 67 of the cylindrical portion 68 of the pressing member 7, the rolling bearing 8, and the one axial side portion of the holder 37 are positioned radially inside the first cylindrical portion 17. More specifically, in the electric friction clutch device 1 of this example, the rolling bearing 8 and the one axial side portion of the holder 37 are disposed radially inside the cylindrical portion 68 of the pressing member 7, and the first cylindrical portion 17 is disposed around the one axial side portion and side plate portion 67 of the cylindrical portion 68, and the elastic member 9.

[0118] The electric friction clutch device 1 of this example controls the supply of electricity to the electric motor that constitutes the electric actuator 6 and adjusts the rotational phase of the drive cam 36 of the cam device 5, thereby switching between a connection mode in which the first member 2 and the second member 3 rotate together, and a disconnection mode in which the first member 2 and the second member 3 rotate relative to each other.

[0119] To switch the electric friction clutch device 1 to the engagement mode, the drive cam 36 is rotated by energizing the electric motor, thereby positioning the rolling elements 38 on the flat surface portion 45 or increasing the amount of movement of the rolling elements 38 onto the inclined surface portion 46. This displaces the holder 37 toward one axial side, which is a direction in which the axial distance from the drive cam 36 increases, and presses the pressing member 7 and the rolling bearing 8 toward one axial side against the elastic force of the elastic member 9. Furthermore, the pressing member 7 presses the first friction plate 32, which is closest to the other axial side, toward one axial side against the elastic forces of the elastic member 9 and the return spring. This presses the first friction plate 32 and the second friction plate 33 against each other, connecting the friction engagement portions 4, and the first member 2 and the second member 3 rotate integrally.

[0120] On the other hand, to switch the electric friction clutch device 1 to the disengagement mode, the drive cam 36 is rotated by energizing the electric motor, thereby positioning the rolling elements 38 on the reference surface 43 or reducing the amount of lift of the rolling elements 38 onto the inclined surface portion 46. This displaces the holder 37 toward the other axial side, which is a direction in which the axial distance between the holder 37 and the drive cam 36 decreases, thereby reducing the force pressing the pressing member 7 toward the one axial side. When the force pressing the pressing member 7 toward the one axial side decreases, the elastic restoring force of the elastic member 9 primarily presses the pressing member 7 and the rolling bearing 8 toward the other axial side. As a result, the force pressing the first friction plate 32 and the second friction plate 33 against each other gradually decreases due to the action of the return spring. Eventually, a gap is formed between the first friction plate 32 and the second friction plate 33, and the force pressing the first friction plate 32 and the second friction plate 33 against each other is lost, i.e., released. As a result, by cutting the frictional engagement portion 4, the first member 2 and the second member 3 can rotate relative to each other.

[0121] When the electric friction clutch device 1 is in use, lubricating oil is pumped in from the radially inner side of the cylindrical portion 20 of the first member 2, and supplied to the cam device 5, rolling bearing 8, etc. through the inner side oil passage 80, and further supplied to the friction engagement portion 4 through the outer side oil passage 79.

[0122] In the electric friction clutch device 1 of this example, the number of input pulses to the electric motor is adjusted to adjust the rotation angle θ of the drive cam 36, thereby controlling the transmission torque capacity T, which is the magnitude of torque that can be transmitted between the first friction plates 32 and the second friction plates 33 without causing slippage. For this purpose, a torque capacity characteristic, which is the relationship between the rotation angle θ of the drive cam 36 and the transmission torque capacity T, is determined in advance. Specifically, for example, a test is conducted to determine the torque capacity characteristic for each product during shipping inspection before the electric friction clutch device 1 is shipped from a manufacturing factory.

[0123] In the test for determining the torque capacity characteristics, first, by energizing the electric motor, the drive cam 36 is rotated in a direction that reduces the axial dimension L of the cam device 5, and the cam-side stopper surface 40 of the drive cam 36 is brought into contact with the holder-side stopper surface 53 of the holder 37. Whether the cam-side stopper surface 40 and the holder-side stopper surface 53 have come into contact can be determined, for example, based on the current value of the electric motor. Alternatively, whether the cam-side stopper surface 40 and the holder-side stopper surface 53 have come into contact may be determined using a pressure sensor or visually.

[0124] Next, the state where the cam side stopper surface 40 and the holder side stopper surface 53 are in contact is set as the reference position (θ=0°), and the transmission torque capacity T is measured while the electric motor is used to rotate the drive cam 36 in a direction that increases the axial dimension L of the cam device 5, thereby determining the torque capacity characteristics as shown schematically in Figure 16.

[0125] The rotation angle θ of the drive cam 36 can be detected, for example, by an encoder attached to the drive cam 36 or the output shaft of the electric motor. Alternatively, the rotation angle θ of the drive cam 36 can be calculated based on the number of pulses input to the electric motor and the reduction ratio of the reducer 65. The torque capacity characteristic can also be found as the relationship between the number of pulses input to the electric motor and the transmission torque capacity T.

[0126] The transmission torque capacity T is expressed as the product of the friction force acting on the friction engagement portions 4 and the average diameter of the friction engagement portions 4. The average diameter of the friction engagement portions 4 can be calculated based on the inner diameter and outer diameter of the first friction plates 32 and the inner diameter and outer diameter of the second friction plates 33.

[0127] The friction force acting on the friction engagement portion 4 can be calculated based on the friction coefficient of the first friction plate 32 and the second friction plate 33 and the surface pressure at the contact portion between the first friction plate 32 and the second friction plate 33. The friction coefficient of the first friction plate 32 and the second friction plate 33 is determined by the type of metal material that constitutes the first friction plate 32 and the second friction plate 33.

[0128] The surface pressure at the contact portion between the first friction plate 32 and the second friction plate 33 can be measured, for example, by a pressure sensor sandwiched between the first friction plate 32 and the second friction plate 33. Alternatively, the surface pressure at the contact portion between the first friction plate 32 and the second friction plate 33 can be calculated based on a measurement value of a load sensor that measures the pressing load of the holder 37 or the pressing member 7. Alternatively, the surface pressure at the contact portion between the first friction plate 32 and the second friction plate 33 can be calculated based on the rotation angle θ of the drive cam 36, the circumferential width of each portion that constitutes the cam surface 39, the inclination angle of the inclined surface portion 46, the gap between the pressing member 7 and the first friction plate 32 that is closest to the other axial side, and the gap between the first friction plate 32 and the second friction plate 33, etc.

[0129] The electric friction clutch device 1, whose torque capacity characteristics have been determined, is shipped from the manufacturing factory, transported to an automobile assembly factory, and assembled into a vehicle at the automobile assembly factory.

[0130] While the vehicle is traveling, the electric friction clutch device 1 is controlled using the torque capacity characteristics determined in advance. Specifically, by adjusting the rotation angle of the drive cam 36 according to the traveling state of the vehicle, the transmission torque capacity of the friction engagement portion 4 is adjusted so that the surface pressure between the first friction plate 32 and the second friction plate 33 does not become excessive, within a range that can prevent slippage between the first friction plate 32 and the second friction plate 33.

[0131] However, in the electric friction clutch device 1 of this example, if slippage occurs at the rolling contact portion between the cam surface 39 of the drive cam 36 and the rolling surface 61 of the rolling element 38, an error may occur in the transmission torque capacity of the friction engagement portion 4, which is calculated based on the rotation angle θ of the drive cam 36. Such an error increases over time.

[0132] Therefore, in the electric friction clutch device 1 of this embodiment, the cam-side stopper surface 40 of the drive cam 36 is brought into contact with the holder-side stopper surface 53 of the holder 37 at approximately regular intervals, thereby correcting the reference position (θ=0°) of the drive cam 36. Therefore, with the electric friction clutch device 1 of this embodiment, it is possible to suppress an increase in error in the transmission torque capacity of the friction engagement unit 4, which is determined based on the rotation angle θ of the drive cam 36, and it is possible to accurately adjust the transmission torque capacity of the friction engagement unit 4 over a long period of time.

[0133] The timing for bringing the cam side stopper surface 40 and the holder side stopper surface 53 into contact with each other can be any timing as long as it does not affect the use of the electric friction clutch device 1. For example, the cam side stopper surface 40 and the holder side stopper surface 53 can be brought into contact with each other every time the electric friction clutch device 1 is switched to the disengagement mode. And / or the cam side stopper surface 40 and the holder side stopper surface 53 can be brought into contact with each other immediately after the power to the mechanical device in which the electric friction clutch device 1 is incorporated is turned on.

[0134] When the electric friction clutch device 1 is incorporated into a vehicle for use, the cam-side stopper surface 40 and the holder-side stopper surface 53 can be brought into contact with each other at any timing that does not impede the running of the vehicle. More specifically, for example, the cam-side stopper surface 40 and the holder-side stopper surface 53 can be brought into contact with each other immediately after the ignition switch is turned on.

[0135] The electric friction clutch device 1 of this example uses a torque capacity characteristic that is determined in advance to adjust the transmission torque capacity of the friction engagement unit 4. Therefore, the electric friction clutch device 1 of this example does not need to provide a load detection unit 111 that detects the load in the rotational direction of the cam plate 106b, as in the clutch device described in WO 2008 / 096438, and therefore manufacturing costs can be reduced.

[0136] In particular, in the electric friction clutch device 1 of this embodiment, the cam-side stopper surface 40 of the drive cam 36 is brought into contact with the holder-side stopper surface 53 of the holder 37 at approximately regular intervals, thereby correcting the reference position (θ=0°) of the drive cam 36. Therefore, even if slippage occurs between the cam surface 39 of the drive cam 36 and the rolling surface 61 of the rolling element 38, it is possible to prevent the error due to this slippage from increasing over time.

[0137] Incidentally, it is also possible to consider the state in which the cam side stopper surface provided on the drive cam abuts against a stopper surface provided on a fixed part such as the body of an automobile in which the electric friction clutch device is incorporated as the reference position of the drive cam (θ=0°).

[0138] However, in this case, the clutch capacity characteristics of the electric friction clutch device can only be determined after the electric friction clutch device is attached to the vehicle body. In other words, the electric friction clutch device must be shipped from its manufacturing plant, transported to an automobile assembly plant, and attached to the vehicle body on the automobile assembly line, and then testing to determine the clutch capacity characteristics of the electric friction clutch device must be performed on the assembly line, which may reduce the efficiency of automobile assembly work and increase automobile manufacturing costs.

[0139] Alternatively, it is conceivable that the clutch capacity characteristics of the electric friction clutch device can be determined in advance at a manufacturing plant for the electric friction clutch device by using the state in which the cam-side stopper surface of the drive cam abuts against a stopper surface of a testing device as the reference position of the drive cam. However, in this case, depending on the shape accuracy of the stopper surface of the fixed part, there is a possibility that the error in the calculated value of the transmission torque capacity based on the previously determined clutch capacity characteristics will be large.

[0140] In contrast, in the electric friction clutch device 1 of this example, the reference position of the drive cam 36 is corrected by abutting the cam-side stopper surface 40 of the drive cam 36 and the holder-side stopper surface 53 of the holder 37, both of which are components of the electric friction clutch device 1. This makes it possible to conduct a test to determine the clutch capacity characteristics at the time of shipping inspection when the electric friction clutch device 1 is shipped from the manufacturing factory, before the electric friction clutch device 1 is attached to the vehicle body. This makes it possible to prevent a decrease in the efficiency of assembly work for automobiles incorporating the electric friction clutch device 1, and to suppress an increase in error in the calculated value of the transmission torque capacity.

[0141] Furthermore, in the electric friction clutch device 1 of this example, the plurality of rolling elements 38 that make up the cam device 5 are rotatably held in the holder 37. Therefore, even if slippage occurs between the cam surface 39 of the drive cam 36 and the rolling surface 61 of the rolling element 38, there is no variation in the amount of ride-up of the cam surface 39 from the reference surface 43 among the plurality of rolling elements 38. Therefore, the amount of axial displacement of the holder 37 can be sufficiently and reliably ensured, and the amount of expansion / contraction of the axial dimension of the cam device 5 can be sufficiently and reliably ensured.

[0142] Therefore, when the electric friction clutch device 1 is switched to the connection mode, a sufficient pressing force between the first friction plates 32 and the second friction plates 33 can be ensured, and a sufficient fastening force can be ensured for the friction engagement portion 4. Furthermore, when the electric friction clutch device 1 is switched to the disconnection mode, the first friction plates 32 and the second friction plates 33 can be sufficiently separated from each other, that is, a gap can be reliably formed between the first friction plates 32 and the second friction plates 33, thereby preventing the occurrence of drag.

[0143] In this example, cylindrical rollers are used as the rolling elements 38. Therefore, slippage can be suppressed compared to when balls 106c are used as the rolling elements of the cam device 106, as in the clutch device 100 described in WO 2008 / 096438.

[0144] Furthermore, in the electric friction clutch device 1 of this example, a retaining member 64 is press-fitted into a locking groove 73 provided in the support shaft 62 and into a locking hole 59 that axially penetrates the support plate portion 56b on the radially inner side of the holder 37. This makes it possible to prevent the support shaft 62 from being accidentally displaced relative to the holder 37 in its axial direction (the radial direction centered on the central axis of the holder 37).

[0145] According to the electric friction clutch device 1 of this embodiment, the manufacturing cost of the first member 2 that supports the first friction plate 32 can be reduced.

[0146] In the clutch device 100 described in WO 2008 / 096438, the first member 103 is formed as a single unit, and includes a small-diameter cylindrical portion 103a that is fitted and fixed to the input member 101, and a large-diameter cylindrical portion 103c that has a first friction plate 105a that is fitted thereon so as to be movable in the axial direction. If a forging process is used to produce the first member 103 having such a generally F-shaped cross section, the processing load will be large, which may increase manufacturing costs.

[0147] In contrast, in this example, the first member 2 having the first cylindrical portion 17 that supports the first friction plate 32 is formed by joining and fixing the flange member 15, which is a pressed product, and the shaft body 16, which is a forged product. This makes it possible to reduce the manufacturing cost of the first member 2.

[0148] Furthermore, in the clutch device 100 described in WO 2008 / 096438, the pressing member 108, the rolling bearing 109, and the drive cam 106a are arranged side by side between the first member 103 and the cam plate 106b in the axial direction. As a result, the clutch device 100 with the conventional structure has a large axial dimension.

[0149] In contrast to this, in this example, the elastic member 9, a part of the pressing member 7, and the rolling bearing 8 are arranged radially inside the first cylindrical portion 17 of the first member 2, regardless of the axial dimension of the cam device 5. Therefore, according to the electric friction clutch device 1 of this example, the axial dimension can be reduced compared to the clutch device 100 of the conventional structure.

[0150] In this example, the pressing plate portion 69 of the pressing member 7 has a substantially S-shaped cross section. That is, the portion of the pressing member 7 that presses the side surface on the other axial side of the first friction plate 32 that is closest to the other axial side has a convex curved surface. This makes it possible to prevent excessive sensitivity to changes in the pressing force of the pressing member 7 that change in accordance with the axial displacement of the holder 37, thereby improving the controllability of the electric friction clutch device 1.

[0151] In addition, in this example, the elastic member 9 is configured as a disc spring, which makes it easier to reduce the axial dimension compared to when a compression coil spring is used as the elastic member that elastically presses the pressing member toward the other axial side. Furthermore, because disc springs have nonlinear spring characteristics, they can prevent excessive loads from being applied to the rolling bearings 8, 24, 48 and the meshing portion between the gear portion 47 and the worm 66, thereby improving durability. However, when implementing the present disclosure, a compression coil spring can also be used as the elastic member.

[0152] [Example 2] A second example of an embodiment of the present disclosure will be described with reference to Fig. 17. In an electric friction clutch device 1a of this example, the second member 3a has a side plate portion 74 in the shape of a substantially hollow circular plate that is bent radially inward from one axial end of the second tubular portion 30, and a substantially cylindrical small-diameter tubular portion 75 that is bent axially from the radially inner end of the side plate portion 74.

[0153] The small-diameter cylindrical portion 75 has a female spline portion 76 on its inner circumferential surface. The second member 3a is connected to a second rotating member such as an input shaft of a transmission or an input shaft of a differential device by spline-engaging the female spline portion 76 with a male spline portion provided on the second rotating member so as to be able to transmit torque to the second rotating member.

[0154] The configuration and effects of other parts of the second example are the same as those of the first example.

[0155] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to Figures 18 to 21. In this example, the structure of the engagement portion between the holder 37a and the support member 10a is changed from that of the first example.

[0156] In this example, the support member 10a does not have the male spline portion 13 that was provided on the support member 10 of the first example. Instead, in this example, the support member 10a has an engagement notch portion 77 at one axial end of the fixed cylindrical portion 11a.

[0157] The engagement cutout portion 77 opens on one axial end face, inner peripheral face, and outer peripheral face of the fixed cylinder portion 11a. The engagement cutout portion 77 has a substantially rectangular opening shape when viewed from the radial direction.

[0158] In this example, the engagement notch 77 is provided at one location in the circumferential direction on one axial end of the fixed cylinder 11a. However, when implementing the present disclosure, engagement notches may be provided at multiple locations in the circumferential direction on one axial end of the support member.

[0159] Furthermore, in this example, the holder 37a does not have the female spline portion 60 that was provided in the holder 37 of the first example. Instead, in this example, the holder 37a has an engaging protrusion 78 that protrudes radially inward from the radially inner surface of the connecting portion 55.

[0160] The engaging protrusion 78 engages with the engaging notch 77. In other words, the engaging protrusion 78 is disposed inside the engaging notch 77. This allows the support member 10a and the holder 37a to be combined in a manner that allows relative axial displacement but prevents relative rotation.

[0161] The engaging protrusion 78 has a substantially rectangular side shape when viewed from the radial direction, and has a circumferential width that is smaller than the circumferential width of the engaging cutout 77 .

[0162] In this example, the engaging protrusion 78 is provided to protrude radially inward from the radially inner surface of one of the multiple connecting portions 55 that make up the holder 37a. However, if the support member has multiple engaging cutout portions, the holder may have multiple engaging protrusions.

[0163] According to this example, the manufacturing costs of the support member 10a and the holder 37a can be reduced compared to the structure in the first example in which the support member 10 and the holder 37 are combined by spline engagement, allowing relative axial displacement but not allowing relative rotation.

[0164] The configuration and effects of other parts of the third example are the same as those of the first example.

[0165] [Example 4] A fourth example of the embodiment of the present disclosure will be described with reference to Figures 22(A) to 24. In this example, the shape of the connecting portions 55a that constitute the holder 37b is changed from that of the third example. In this example, when viewed in the axial direction, the radially outer surface of each connecting portion 55a is located radially inward of an imaginary circle α (see Figure 24) that is centered on the central axis of the holder 37b and tangent to the radially outer surface of the holding portion 54.

[0166] Specifically, the holder 37b has an end face shape that is substantially triangular when viewed from the axial direction.

[0167] More specifically, when viewed from the axial direction, the radial outer surface of each of the connecting portions 55a that make up the holder 37b has a compound curved contour shape in which two straight line portions are smoothly connected by an arc portion having a radius of curvature smaller than the radius of the imaginary circle α.

[0168] However, when implementing the present disclosure, the contour shape of the radially outer surface of the connecting portion can be any shape, as long as at least a portion of the radially outer surface of the connecting portion is centered on the central axis of the holder and located radially inward of an imaginary circle tangent to the radially outer surface of the holding portion.

[0169] In this example, the radially inner surface of each of the connecting portions 55a has an arc-shaped contour centered on the central axis of the holder 37b when viewed from the axial direction. Therefore, in this example, the radial width of each of the connecting portions 55a increases from the circumferential center toward both circumferential ends.

[0170] When viewed from the axial direction, holder 37b of this example has a thinner wall than holder 37a of the third example because the radially outer surfaces of each connecting portion 55a are located radially inward of imaginary circle α. This allows the amount of metal material constituting holder 37b to be reduced, thereby reducing the manufacturing cost of holder 37b.

[0171] The configuration and effects of other parts of the fourth example are the same as those of the first and third examples.

[0172] [Example 5] A fifth example of the embodiment of the present disclosure will be described with reference to Figures 25 and 26. In this example, the structure of the engagement portion between the holder 37c and the support member 10b is changed from that in the third example.

[0173] In this example, the holder 37c does not have the engaging protrusion 78 that the holder 37a of the third example has. That is, the inner peripheral surface of the holder 37c is configured to have a substantially cylindrical surface shape.

[0174] In this example, the fixed cylinder portion 11b constituting the support member 10b has an inner diameter and an outer diameter larger than the inner diameter and outer diameter of the fixed cylinder portion 11a constituting the support member 10a of Example 3. In addition, the fixed cylinder portion 11b has engagement notches 77a at multiple locations in the circumferential direction at one end on one axial side.

[0175] Each engagement cutout 77a has a circumferential width slightly larger than the circumferential width of the retaining portion 54, and engages with a radially outer portion of the retaining portion 54. Specifically, the radially outer support plate portion 56b of each retaining portion 54 is disposed inside the engagement cutout 77a. This allows the support member 10b and holder 37c to be combined in a manner that allows relative axial displacement but prevents relative rotation.

[0176] The configuration and effects of other parts of the fifth example are similar to those of the first, third, and fourth examples. [Explanation of symbols]

[0177] 1, 1a Electric friction clutch device 2 First member 3, 3a Second member 4 Friction engagement part 5 Cam device 6 Electric Actuators 7 Pressing member 8. Rolling bearings 9 Elastic member 10, 10a, 10b Support members 11, 11a, 11b Fixed cylinder part 12 Flange 13 Male spline part 14a, 14b through hole 15 Flange member 16 axis body 17 First cylinder part 18 Circular part 19 Inner diameter uneven part 20 Cylindrical part 21 Outward flange 22 Locking groove 23 Female spline part 24 Radial rolling bearing 25 Inner Circle 26 Outer ring 27 Rolling elements 28 Retaining ring 29 Step surface 30 Second cylinder part 31 Outer diameter side uneven part 32 1st friction plate 33 Second friction plate 34 spacer 35 retaining ring 36 Drive cam 37, 37a, 37b, 37c holder 38 Rolling elements 39 Cam surface 40 Cam side stopper surface 41 Main body 42 Protrusion 43 Reference plane 44 Convex part 45 Flat surface section 46 Slope section 47 Gear section 48 Radial Rolling Bearing 49 Inner Circle 50 outer ring 51 rolling elements 52 Step surface 53 Holder side stopper surface 54 Holding part 55, 55a connection part 56a, 56b Support plate part 57a, 57b connecting plate part 58a, 58b support hole 59 Locking hole 60 Female spline part 61 rolling surface 62 Support shaft 63 Around 64 Anti-slip member 65 Reducer 66 Warm 67 Side plate part 68 Cylindrical part 69 Pressure plate 70 outer ring 71 Inner circle 72 balls 73 Locking groove 74 Side plate part 75 Small diameter cylinder part 76 Female spline part 77, 77a Engagement notch 78 Engagement protrusion 79 Outer oil passage 80 Inner oil passage 100 Clutch device 101 Input member 102 Output member 103 First member 103a Small diameter cylinder part 103b Side plate part 103c Large diameter cylinder 104 Second member 104a Circular part 104b Cylindrical part 105 Friction engagement part 105a 1st friction plate 105b 2nd friction plate 106 Cam device 106a Drive cam 106a1 Drive side cam surface 106a2 Gear section 106b Cam plate 106b1 Fixed side cam surface 106c ball 107 Electric Actuator 107a Electric motor 107b Reducer 107b1 Output gear 108 Pressing member 109 Rolling bearings 110 Elastic member 111 Load detection unit

Claims

1. A first member; a second member supported coaxially with the first member and capable of relative rotation with respect to the first member; a friction engagement portion having at least one first friction plate and one second friction plate supported so as to be capable of relative displacement in the axial direction; a cam device including: a drive cam having a cam surface provided on a side surface on one axial side and a cam side stopper surface facing in the circumferential direction, the drive cam being rotatable relative to a fixed portion that does not rotate even when in use but supported so as not to be displaced in the axial direction; a holder having a holder side stopper surface that abuts against the cam side stopper surface when the distance between the drive cam and the holder is shortest, the holder being supported so as to be displaceable in the axial direction but not to be rotated; and a plurality of rolling elements held by the holder, the rolling elements having rolling surfaces that come into rolling contact with the cam surface; an electric actuator that rotates the drive cam; a pressing member that faces a side surface on the other axial side of the friction plate that is located furthest on the other axial side among the first friction plate and the second friction plate, and is supported so as to be movable toward and away from the friction plate located furthest on the other axial side in the axial direction; a rolling bearing disposed between the holder and the pressing member; an elastic member that elastically biases the pressing member toward the other axial side; Equipped with By driving the drive cam to rotate with the electric actuator, the holder is displaced in a direction that widens the gap between it and the drive cam, and the first friction plate and the second friction plate are pressed together, thereby switching to a connection mode in which the first member and the second member rotate together; and by displacing the holder in a direction that narrows the gap between it and the drive cam, the force pressing the first friction plate and the second friction plate together is released, thereby switching to a disconnection mode in which the first member and the second member rotate relatively. Electric friction clutch device.

2. The cam surface is formed by alternately arranging a plurality of reference surfaces, each of which is formed by a flat surface perpendicular to the central axis of the drive cam, and a plurality of protrusions, each of which protrudes toward one axial side from the reference surfaces, in a circumferential direction, the cam-side stopper surface is provided on a side surface of at least one of the plurality of protrusions, the side surface facing the rotation direction of the drive cam when the gap between the drive cam and the holder is reduced.

2. The electric friction clutch device according to claim 1.

3. The holder has a plurality of holding portions arranged at a plurality of locations in the circumferential direction and rotatably holding the plurality of rolling elements, and a plurality of connecting portions connecting two of the plurality of holding portions adjacent to each other in the circumferential direction.

2. The electric friction clutch device according to claim 1.

4. each of the plurality of holding portions has a portion that protrudes toward the other axial direction beyond a side surface of the plurality of connecting portions on the other axial direction; the holder-side stopper surface is a portion of at least one of the plurality of holding portions that protrudes toward the other axial direction beyond a side surface of the plurality of connecting portions on the other axial direction, and is provided at a portion that faces the cam-side stopper surface in the circumferential direction.

4. The electric friction clutch device according to claim 3.

5. the fixed portion has at least one engagement notch at one axial end that engages with a part of the holder to allow relative axial displacement but not allow relative circumferential displacement, and the fixed portion includes a support member including a fixed cylindrical portion that is fitted into the holder to allow relative axial displacement.

4. The electric friction clutch device according to claim 3.

6. the holder has at least one engaging protrusion that protrudes radially inward from a radially inner surface of at least one holding portion among the plurality of holding portions or a radially inner surface of at least one connecting portion among the plurality of connecting portions, and that engages with the at least one engaging notch portion to enable relative displacement in the axial direction but prevent relative displacement in the circumferential direction; 6. The electric friction clutch device according to claim 5.

7. the at least one engagement notch is constituted by a plurality of engagement notches, the plurality of engagement notches engage with the plurality of holding portions; 6. The electric friction clutch device according to claim 5.

8. When the holder is viewed from the axial direction, radially outer surfaces of the plurality of connecting portions are located radially inward of the circumscribed circles of the plurality of holding portions.

4. The electric friction clutch device according to claim 3.

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