Clutch device

Abstract

In the present invention, a pressure plate 70 has: an annular wall 74A extending to the first direction D1 side; and a pressure-side fitting part 88 formed on an inner peripheral surface in the radial direction of the annular wall 74A and externally fitted to a center-side fitting part 58 so as to be slidable. An end face 74D on the first direction D1 side of the annular wall 74A is positioned closer to the first direction D1 side than an end 58D in the second direction of the center-side fitting part 58, in a state where the pressure plate 70 is in contact with a stopper plate 100.

Description

Clutch device

[0001] The present invention relates to a clutch device. More specifically, it relates to a clutch device that arbitrarily transmits or blocks the rotational driving force of an input shaft that is rotationally driven by a power source such as an engine to an output shaft.

[0002] Conventionally, vehicles such as motorcycles have a clutch device. The clutch device is disposed between the engine and the drive wheel and transmits or blocks the rotational driving force of the engine to the drive wheel. The clutch device usually includes a plurality of input-side rotating plates that rotate by the rotational driving force of the engine, and a plurality of output-side rotating plates connected to an output shaft that transmits the rotational driving force to the drive wheel. The input-side rotating plates and the output-side rotating plates are alternately arranged in the stacking direction. By pressing and separating the input-side rotating plates and the output-side rotating plates, transmission or interruption of the rotational driving force is performed.

[0003] For example, Patent Document 1 discloses a clutch device including a clutch center and a pressure plate that can approach and separate from the clutch center. The pressure plate is configured to be able to press the input-side rotating plate and the output-side rotating plate. In such a clutch device, the output-side rotating plate is held by the pressure plate.

[0004] Japanese Patent No. 5847551

[0005] In the clutch device as described above, when assembling the clutch center, the pressure plate, the input-side rotating plate, and the output-side rotating plate, there is a possibility that the radial positions of the input-side rotating plate and the output-side rotating plate may shift. Therefore, when assembling the clutch device, it is necessary to align the radial positions of the input-side rotating plate and the output-side rotating plate.

[0006] The present invention has been made in view of this point, and an object thereof is to provide a clutch device in which positioning of the radial positions of the input-side rotating plate and the output-side rotating plate is easy.

[0007] The clutch device according to the present invention is a clutch device for transmitting or interrupting the rotational driving force of an input shaft to an output shaft, comprising: a clutch center housed in a clutch housing that rotates upon receiving the rotational driving force and holds a plurality of input-side rotating plates arranged in the axial direction which is the direction of the axis of the output shaft, and which rotates together with the output shaft; a plurality of output-side rotating plates arranged alternately with the input-side rotating plates in the axial direction; and a component provided to be able to approach and move away from the clutch center in the axial direction and to be rotatable relative to it, and which holds the output-side rotating plates and the input-side rotating plates and the output-side rotating plates The clutch includes a pressure plate that presses against a plate, a clutch spring that biases the pressure plate in the first direction, where the direction in which the pressure plate approaches the clutch center along the axial direction is defined as the first direction, and the direction in which the pressure plate moves away from the clutch center along the axial direction is defined as the second direction, and a stopper plate fixed to the clutch center and in contact with the pressure plate, thereby restricting the pressure plate from moving away from the clutch center by a predetermined distance or more in the second direction. The clutch center has an output shaft holding portion through which the output shaft is inserted, and a center-side fitting portion located radially outside the output shaft than the output shaft holding portion, into which the pressure plate is slidably fitted in the axial direction. The pressure plate has a cylindrical portion formed in a cylindrical shape that extends in the first direction. The cylindrical portion has an annular wall slidably fitted in the axial direction to the center-side fitting portion, and pressure-side fitting teeth that protrude radially from the annular wall and hold the output-side rotating plate. The end of the annular wall in the first direction is located on the first direction side of the center-side fitting portion than the end of the center-side fitting portion in the second direction when the pressure plate is in contact with the stopper plate.

[0008] According to the clutch device of the present invention, when the pressure plate is in contact with the stopper plate, the end of the annular wall on the first direction side is located on the first direction side of the end of the center-side fitting portion on the second direction side. As a result, even when the pressure plate is in contact with the stopper plate, the fitting between the pressure plate and the clutch center does not disengage. Here, the output-side rotating plate is held by the pressure plate. Therefore, even when the pressure plate is in contact with the stopper plate, the radial positional displacement between the input-side rotating plate and the output-side rotating plate is suppressed. As a result, radial positioning between the input-side rotating plate and the output-side rotating plate can be easily performed.

[0009] Another clutch device according to the present invention is a clutch device for transmitting or interrupting the rotational driving force of an input shaft to an output shaft, comprising: a clutch center housed in a clutch housing that rotates upon receiving the rotational driving force and holds a plurality of input-side rotating plates arranged in the axial direction which is the direction of the axis of the output shaft, and which rotates together with the output shaft; a plurality of output-side rotating plates arranged alternately with the input-side rotating plates in the axial direction; and a component provided to be able to approach or move away from the clutch center in the axial direction and to be rotatable relative to it, and which holds the output-side rotating plates and the input-side rotating plates and the output-side rotating plate. The clutch includes a pressure plate that presses against a rolling plate, a clutch spring that biases the pressure plate in the first direction, where the direction in which the pressure plate approaches the clutch center along the axial direction is defined as the first direction, and the direction in which the pressure plate moves away from the clutch center along the axial direction is defined as the second direction, and a stopper plate fixed to the clutch center and in contact with the pressure plate, thereby restricting the pressure plate from moving away from the clutch center by a predetermined distance or more in the second direction. The clutch center has an output shaft holding portion through which the output shaft is inserted, and a center-side fitting portion located radially outside the output shaft than the output shaft holding portion, into which the pressure plate is slidably fitted in the axial direction. The pressure plate is formed in a cylindrical shape extending in the first direction and has an annular wall slidably fitted in the axial direction to the center-side fitting portion, and pressure-side fitting teeth that protrude radially from the annular wall and hold the output-side rotating plate. The end of the annular wall in the first direction is located in the first direction more than the end of the center-side fitting portion in the second direction when the pressure plate is in its furthest position from the clutch center.

[0010] In a clutch device otherwise relating to the present invention, when the pressure plate is at its furthest distance from the clutch center, the end of the annular wall on the first direction side is located on the first direction side more than the end of the center-side fitting portion on the second direction side. As a result, even when the pressure plate is at its furthest distance from the clutch center, the fitting between the pressure plate and the clutch center does not disengage. Here, the output-side rotating plate is held by the pressure plate. Therefore, even if the pressure plate contacts the stopper plate, the radial positional displacement between the input-side rotating plate and the output-side rotating plate is suppressed. As a result, radial positioning of the input-side rotating plate and the output-side rotating plate can be easily performed.

[0011] Another clutch device according to the present invention is a clutch device for transmitting or interrupting the rotational driving force of an input shaft to an output shaft, comprising: a clutch center housed in a clutch housing that rotates upon receiving the rotational driving force and holds a plurality of input-side rotating plates arranged in an axial direction which is the direction of the axis of the output shaft, and which rotates together with the output shaft; a plurality of output-side rotating plates arranged alternately with the input-side rotating plates in the axial direction; a pressure plate provided so as to be able to approach and move away from the clutch center in the axial direction and to be rotatable relative to it, and which holds the output-side rotating plates and presses the input-side rotating plates and the output-side rotating plates; When the direction in which the pressure plate approaches the clutch center along the axial direction is defined as the first direction, and the direction in which the pressure plate moves away from the clutch center along the axial direction is defined as the second direction, the device includes a clutch spring that biases the pressure plate in the first direction, and a stopper plate that is fixed to the clutch center and, by contacting the pressure plate, restricts the pressure plate from moving away from the clutch center by a predetermined distance or more in the second direction. The clutch center includes an output shaft holding portion through which the output shaft is inserted, a center-side fitting portion located radially outward from the output shaft holding portion and into which the pressure plate is slidably fitted in the axial direction, a center-side pressing surface located radially outward from the center-side fitting portion and sandwiching the input-side rotating plate and the output-side rotating plate between itself and the pressure plate, and a plurality of center-side cam portions having center-side assist cam surfaces located radially outward from the output shaft holding portion. The pressure plate has a plurality of pressure cam portions having pressure-side assist cam surfaces facing the center-side assist cam surfaces in the circumferential direction. The pressure-side assist cam surfaces and the center-side assist cam surfaces are configured to increase the pressing force between the input-side rotating plate and the output-side rotating plate by generating a force in a direction that brings the pressure plate closer to the clutch center when the pressure plate rotates relative to the clutch center.When the pressure-side assist cam surface and the center-side assist cam surface are in contact, at least a portion of the pressure plate is located on the first direction side of the center-side pressing surface of the clutch center.

[0012] In another clutch device according to the present invention, when the pressure-side assist cam surface and the center-side assist cam surface are in contact, at least a portion of the pressure plate is located on the first direction side relative to the pressing surface. Therefore, when the pressure-side assist cam surface and the center-side assist cam surface are in contact, the input-side rotating plate and the output-side rotating plate are prevented from coming off the pressure plate. This makes it easier to radially position the input-side rotating plate and the output-side rotating plate.

[0013] According to the present invention, a clutch device is provided that facilitates axial positioning of the input-side rotating plate and the output-side rotating plate.

[0014] Figure 1 is a cross-sectional view of the clutch device according to the first embodiment. Figure 2 is an enlarged view of the area near the output side rotating plate as seen from the first direction. Figure 3 is a perspective view of the clutch center according to the first embodiment. Figure 4 is a plan view of the clutch center according to the first embodiment as seen from the second direction. Figure 5 is a plan view of the clutch center according to the first embodiment as seen from the first direction. Figure 6 is a side view of the clutch center according to the first embodiment. Figure 7 is a perspective view of the pressure plate according to the first embodiment. Figure 8 is a perspective view of the pressure plate according to the first embodiment. Figure 9 is an enlarged view of the area around the protruding part in Figure 1. Figure 10 is a plan view of the pressure plate according to the first embodiment as seen from the first direction. Figure 11 is a side view of the pressure plate according to the first embodiment. Figure 12 is a cross-sectional view of the pressure plate according to the first embodiment. Figure 13A is a schematic diagram illustrating the operation of the center side assist cam surface and the pressure side assist cam surface. Figure 13B is a schematic diagram illustrating the operation of the center-side slipper cam surface and the pressure-side slipper cam surface. Figure 14 is a plan view of the pressure plate according to the first embodiment, viewed from the second direction. Figure 15A is a plan view of the first spring and the second spring. Figure 15B is a side view of the first spring and the second spring. Figure 16 is a plan view showing the clutch center and the pressure plate assembled. Figure 17 is a cross-sectional view of the clutch device when the center-side slipper cam surface and the pressure-side slipper cam surface are in contact. Figure 18 is a cross-sectional view of the clutch device in a half-clutch state. Figure 19 is a cross-sectional view of the clutch device when the pressure plate is in contact with the stopper plate. Figure 20A is a cross-sectional view of the area around the protrusion before the pressure plate is assembled to the clutch center. Figure 20B is a cross-sectional view of the area around the protrusion when the pressure plate is assembled to the clutch center. Figure 20C is a view of Figure 20A from the first direction. Figure 21 is a perspective view of a modified pressure plate. Figure 22 is a perspective view of a modified pressure plate. Figure 23 is a cross-sectional view of a modified pressure plate. Figure 24 is a perspective view of a clutch center according to a second embodiment.Figure 25 is a perspective view of the clutch center according to the second embodiment. Figure 26 is a perspective view of the pressure plate according to the second embodiment. Figure 27 is a plan view of the pressure plate according to the second embodiment. Figure 28 is a cross-sectional view of the clutch device according to the third embodiment. Figure 29 is an enlarged view of the area around the protruding portion in Figure 28.

[0015] Hereinafter, embodiments of the clutch device according to the present invention will be described with reference to the drawings. Naturally, the embodiments described herein are not intended to particularly limit the present invention. Furthermore, the same reference numerals are used for members and parts that perform the same function, and redundant explanations are omitted or simplified as appropriate.

[0016] <First Embodiment> Figure 1 is a cross-sectional view of the clutch device 10 according to this embodiment. The clutch device 10 is installed in a vehicle such as a motorcycle. The clutch device 10 is a device that transmits or interrupts the rotational driving force of the input shaft (e.g., crankshaft) of a power source to the output shaft 15. The power source is, for example, the engine or electric motor of a motorcycle. The clutch device 10 is a device for transmitting or interrupting the rotational driving force of the input shaft to the drive wheel (rear wheel) via the output shaft 15.

[0017] In the following description, the direction in which the pressure plate 70 and the clutch center 40 of the clutch device 10 are aligned is referred to as direction D. In this embodiment, direction D is approximately horizontal. The direction in which the pressure plate 70 approaches the clutch center 40 is referred to as the first direction D1, and the direction in which the pressure plate 70 moves away from the clutch center 40 is referred to as the second direction D2. In this embodiment, the axial direction of the output shaft 15, the axial direction of the clutch housing 30, the axial direction of the clutch center 40, and the axial direction of the pressure plate 70 are the same as direction D. In the following description, unless otherwise specified, "axial direction" refers to the axial direction of the output shaft 15. Furthermore, the circumferential directions of the output shaft 15, the clutch housing 30, the clutch center 40, and the pressure plate 70 are the same, and this is referred to as the circumferential direction S (see Figure 2). With respect to the circumferential direction S, the direction from one pressure-side cam portion 90 to the other pressure-side cam portion 90 is defined as the first circumferential direction S1 (see Figure 7), and the direction from the other pressure-side cam portion 90 to the first pressure-side cam portion 90 is defined as the second circumferential direction S2 (see Figure 7). The pressure plate 70 and the clutch center 40 rotate in the first circumferential direction S1. In this embodiment, the radial directions of the output shaft 15, clutch housing 30, clutch center 40, and pressure plate 70 are the same. In the following description, unless otherwise specified, "radial direction" refers to the radial direction of the output shaft 15. However, the above directions are merely defined for the convenience of explanation and do not limit the installation configuration of the clutch device 10 in any way, nor do they limit the present invention in any way.

[0018] Figure 1 shows the clutch device 10 in the clutch ON state, as described later, with the pressure plate 70 closest to the clutch center 40, and the input side rotating plate 20 and the output side rotating plate 22 pressed against each other. As shown in Figure 1, the clutch device 10 includes an output shaft 15, an input side rotating plate 20, an output side rotating plate 22, a clutch housing 30, a clutch center 40, a pressure plate 70, a clutch spring 25, a stopper plate 100, a judder spring 120, a first spring 130A, and a second spring 130B.

[0019] As shown in Figure 1, the output shaft 15 is a hollow shaft. One end of the output shaft 15 rotatably supports the input gear 35 and clutch housing 30, which will be described later, via a needle bearing 15A. The output shaft 15 is fixed to the clutch center 40 by a nut 15B. The output shaft 15 rotates integrally with the clutch center 40. The other end of the output shaft 15 is connected to, for example, a motorcycle transmission (not shown).

[0020] As shown in Figure 1, the output shaft 15 is equipped with a push rod 16A in its hollow portion 15H and a push member 16B provided adjacent to the push rod 16A. The hollow portion 15H functions as an oil flow passage. The oil flows inside the output shaft 15, i.e., inside the hollow portion 15H. The push rod 16A and the push member 16B are slidably mounted inside the hollow portion 15H of the output shaft 15. One end of the push rod 16A (the left end in the figure) is connected to a motorcycle clutch operating lever (not shown), and when the clutch is disengaged, the operation of the clutch operating lever causes it to slide inside the hollow portion 15H and press the push member 16B in a second direction D2. A part of the push member 16B protrudes outward from the output shaft 15 (in this case, in the second direction D2) and is connected to a release bearing 18 provided on the pressure plate 70. The push rod 16A and other parts of the push member 16B are formed to be thinner than the inner diameter of the hollow portion 15H, ensuring oil flow within the hollow portion 15H. The push rod 16A may, for example, be connected to a clutch operation switch, and pressing the clutch operation switch will cause the push member 16B to be pressed in the second direction D2.

[0021] The clutch housing 30 is made of an aluminum alloy. The clutch housing 30 is formed in a bottomed cylindrical shape. As shown in Figure 1, the clutch housing 30 has a substantially circular bottom wall 31 and a side wall 33 extending in a second direction D2 from the edge of the bottom wall 31. The clutch housing 30 holds a plurality of input-side rotating plates 20.

[0022] As shown in Figure 1, an input gear 35 is provided on the bottom wall 31 of the clutch housing 30. The input gear 35 is fixed to the bottom wall 31 by rivets 35B via a torque damper 35A. The input gear 35 meshes with a drive gear (not shown) that rotates due to the rotational drive of the engine's input shaft. The input gear 35 rotates independently of the output shaft 15 and integrally with the clutch housing 30.

[0023] The input-side rotating plate 20 is rotationally driven by the rotational drive of the input shaft. As shown in Figure 1, the input-side rotating plate 20 is held on the inner circumferential surface 33N of the side wall 33 of the clutch housing 30. In this embodiment, the inner circumferential surface 33N extends radially outward as it moves toward the second direction D2, and is inclined from the axial direction of the output shaft 15. The input-side rotating plate 20 is held by engaging with a notch 30C (see also Figure 2) formed in the side wall 33 of the clutch housing 30. The input-side rotating plate 20 is held in the clutch housing 30 by spline fitting. The input-side rotating plate 20 is provided so as to be displaceable along the axial direction of the clutch housing 30. The input-side rotating plate 20 is provided so as to be rotatable integrally with the clutch housing 30.

[0024] The input-side rotating plate 20 is a component that is pressed against the output-side rotating plate 22. The input-side rotating plate 20 is a flat plate formed in an annular shape. The input-side rotating plate 20 is formed by punching out an annular shape from a thin sheet of SPCC (cold-rolled steel sheet) material. Friction material (not shown) consisting of multiple pieces of paper is attached to the front and back surfaces of the input-side rotating plate 20. Grooves with a depth of several micrometers to tens of micrometers are formed between the friction material to hold oil.

[0025] All output-side rotating plates 22 are held by the pressure plate 70. The output-side rotating plates 22 are held by the pressure-side fitting teeth 77 of the pressure plate 70, which will be described later. The output-side rotating plates 22 are provided so as to be displaceable along the axial direction of the clutch center 40. The output-side rotating plates 22 are provided so as to be rotatable integrally with the clutch center 40.

[0026] The output-side rotating plate 22 is a component that is pressed against the input-side rotating plate 20. The output-side rotating plate 22 is a flat plate formed in an annular shape. The output-side rotating plate 22 is formed by punching out an annular shape from a thin sheet material made of SPCC material. Grooves with a depth of several micrometers to several tens of micrometers are formed on the front and back surfaces of the output-side rotating plate 22 to retain oil. The front and back surfaces of the output-side rotating plate 22 are each subjected to a surface hardening treatment to improve wear resistance. The friction material provided on the input-side rotating plate 20 may be provided on the output-side rotating plate 22 instead of the input-side rotating plate 20, or it may be provided on both the input-side rotating plate 20 and the output-side rotating plate 22.

[0027] Figure 2 shows the clutch housing 30, the input-side rotating plate 20, the output-side rotating plate 22, and the protruding portion 75 of the pressure plate 70, which will be described later. The inner circumferential surface 33N of the side wall 33 (see Figure 1) faces radially outward from the protruding portion 75. As shown in Figure 2, the output-side rotating plate 22 has a ring-shaped body portion 22a, a plurality of rotating plate fitting teeth 22b, and a plurality of rotating plate grooves 22c. The rotating plate fitting teeth 22b extend radially inward from the inner circumferential edge 22N of the body portion 22a. Multiple rotating plate fitting teeth 22b are formed in a row in the circumferential direction S. The rotating plate grooves 22c are grooves formed between adjacent rotating plate fitting teeth 22b in the circumferential direction S. The pressure-side fitting teeth 77, which will be described later, fit into the rotating plate grooves 22c. When the rotational axes of the clutch housing 30 and the output-side rotating plate 22 are located coaxially, the radial distance between the inner circumferential surface 33N of the side wall 33 and the outer circumferential edge 22U of the output-side rotating plate 22 is length L20. As shown in Figure 1, length L20 is the narrowest radial distance between the inner circumferential surface 33N and the output-side rotating plate 22 in direction D, that is, the distance closest to the first direction D1.

[0028] The clutch center 40 is housed in the clutch housing 30. The clutch center 40 is positioned concentrically with the clutch housing 30. As shown in Figure 3, the clutch center 40 has a ring-shaped center-side flange 68, a center-side body portion 42 located radially inward of the center-side flange 68, and a center-side recess 59 formed between the center-side body portion 42 and the center-side flange 68. The clutch center 40 is rotationally driven together with the output shaft 15 (see Figure 1).

[0029] As shown in Figure 3, the center-side main body portion 42 comprises an annular boss portion 43, a plurality of center-side cam portions 60 connected to the boss portion 43, and a plurality of center-side fitting portions 58. The radially inner portion of the boss portion 43 constitutes an output shaft holding portion 50 that is held by the output shaft 15. As shown in Figure 4, the radially outer edge portion 43E of the boss portion 43 is connected to the center-side cam portion 60. In this embodiment, a center-side cam portion 60 is connected to each of the three outer edge portions 43E.

[0030] As shown in Figure 3, the output shaft holder 50 has an insertion hole 51 into which the output shaft 15 (see Figure 1) is inserted and spline fitted. Multiple spline grooves are formed on the inner circumferential surface 50A of the output shaft holder 50 along the axial direction. The output shaft 15 is connected to the output shaft holder 50.

[0031] As will be described in detail later, the clutch device 10 is equipped with an assist & slipper (registered trademark) mechanism. The assist & slipper (registered trademark) mechanism is a mechanism that generates assist torque, which is a force that increases the pressing force (contact force) between the input side rotating plate 20 (see Figure 1) and the output side rotating plate 22 (see Figure 1), or slipper torque, which is a force that decreases the pressing force between the input side rotating plate 20 and the output side rotating plate 22. The center side cam portion 60 has cam surfaces 60A and 60S, which are inclined surfaces that constitute the assist & slipper (registered trademark) mechanism. The center side cam portion 60 is connected to the radially outside of the boss portion 43. The center side cam portion 60 protrudes from the boss portion 43 in a second direction D2. As shown in Figure 4, the center side cam portions 60 are arranged at equal intervals in the circumferential direction S of the clutch center 40. In this embodiment, the clutch center 40 has three center side cam portions 60, but the number of center side cam portions 60 is not limited to three.

[0032] As shown in Figure 3, the end 60E of the center cam portion 60 on the first direction D1 side is connected to the center fitting portion 58. As shown in Figure 4, the center cam portion 60 is formed integrally, but here it is assumed to have the following two parts aligned in the circumferential direction S. The center cam portion 60 comprises an assist cam portion 63A having a center assist cam surface 60A, and a slipper cam portion 63S having a center slipper cam surface 60S. The slipper cam portion 63S is aligned with respect to the assist cam portion 63A on the first circumferential direction S1 side. The assist cam portion 63A and the slipper cam portion 63S are formed integrally. As shown in Figure 3, the assist cam portion 63A extends further toward the second direction D2 than the slipper cam portion 63S. The dimension of the assist cam portion 63A in direction D is greater than the dimension of the slipper cam portion 63S in direction D. The assist-side cam portion 63A and the slipper-side cam portion 63S may be formed as separate components.

[0033] In this embodiment, the clutch center 40 rotates in the direction from the assist-side cam portion 63A toward the slipper-side cam portion 63S (i.e., the first circumferential direction S1). The center-side assist cam surface 60A is configured to generate a force in the direction from the pressure plate 70 toward the clutch center 40 in order to increase the pressing force (contact force) between the input-side rotating plate 20 (see Figure 1) and the output-side rotating plate 22 (see Figure 1) when the clutch center 40 rotates relative to the pressure plate 70 (see Figure 1). In this embodiment, when the above force is generated, the position of the pressure plate 70 relative to the clutch center 40 does not change, and the pressure plate 70 does not need to physically approach the clutch center 40. However, the pressure plate 70 may be physically displaced relative to the clutch center 40. The center-side assist cam surface 60A extends toward the second circumferential direction S2 as it goes toward the second direction D2, and is inclined with respect to the axial direction. The center-side slipper cam surface 60S is configured to reduce the pressing force (contact force) between the input-side rotating plate 20 and the output-side rotating plate 22 when the clutch center 40 rotates relative to the pressure plate 70. When the pressing force decreases, the position of the pressure plate 70 changes in the circumferential direction S and the axial direction (direction D) so that it moves away from the clutch center 40. The center-side slipper cam surface 60S extends toward the second circumferential direction S2 as it moves toward the second direction D2, and is inclined with respect to the axial direction. As shown in Figure 4, the center-side assist cam surface 60A of one center-side cam portion 60L and the center-side slipper cam surface 60S of the other center-side cam portion 60M face each other in the circumferential direction S. Note that the cross-sectional view in Figure 1 is a cross-sectional view when the center-side assist cam surface 60A and the pressure-side assist cam surface 90A, which will be described later, are in contact.

[0034] As shown in Figure 3, a stepped portion 60T is formed next to the center slipper cam surface 60S on the center cam portion 60. The stepped portion 60T extends radially. As shown in Figure 4, the radially inner portion of the stepped portion 60T is connected to the boss portion 43. The radially outer portion of the stepped portion 60T is connected to the center fitting portion 58. The stepped portion 60T is also connected to the end of the center slipper cam surface 60S on the second direction D2 side. Furthermore, the stepped portion 60T is located approximately in the center of the center cam portion 60 in direction D.

[0035] A portion of the end face 63E on the second direction D2 side of the assist-side cam portion 63A and a portion of the end face 63F (see Figure 5) on the first direction D1 side of the assist-side cam portion 63A are positioned offset from each other in the circumferential direction S. As shown in Figure 6, the end of the end face 63E on the first circumferential direction S1 side is offset towards the second circumferential direction S2 side than the end of the end face 63F on the first circumferential direction S1 side.

[0036] As shown in Figure 3, the main outer surface 63P is formed by the outer surface of the assist-side cam portion 63A and the outer surface of the slipper-side cam portion 63S. The main outer surface 63P is formed across the assist-side cam portion 63A and the slipper-side cam portion 63S. In addition, the assist-side cam portion 63A has a sub-outer surface 61A that intersects with the main outer surface 63P. The sub-outer surface 61A is connected to the center-side assist cam surface 60A. The sub-outer surface 61A extends radially inward as it moves toward the first direction D1 and is inclined with respect to the axial direction. That is, the sub-outer surface 61A is inclined to move radially inward from the main outer surface 63P as it moves toward the first direction D1. The sub-outer surface 61A may be parallel to the axis of the output shaft 15. Of the main outer peripheral surface 63P, at least the side on the sub outer peripheral surface 61A (i.e., the side on the second circumferential direction S2) is inclined so that it moves radially outward from the sub outer peripheral surface 61A as it moves toward the first direction D1. Therefore, the radial length of the center-side assist cam surface 60A increases toward the second direction D2. Here, as shown in Figure 4, the longest radial length of the center-side assist cam surface 60A is defined as length L1. The longest radial length of the center-side slipper cam surface 60S is defined as length L2. Length L1 is longer than length L2. The radial midpoint position at the end of the second direction D2 of the center-side assist cam surface 60A coincides with the radial midpoint position at the end of the second direction D2 of the center-side slipper cam surface 60S. Arc AR1, centered on axis CL and passing through the midpoint of the radial direction at the end of the second direction D2 of the center-side assist cam surface 60A, also passes through the midpoint of the radial direction at the end of the second direction D2 of the center-side slipper cam surface 60S. Lengths L1 and L2 may be the same. Arc AR1 is located on the outer diameter side of Arc AR2, which is centered on axis CL and passes through the center 54C of the screw portion 54a, which will be described later. As a result, the center-side assist cam surface 60A and the center-side slipper cam surface 60S are located on the radially outer side of the clutch center 40.Therefore, when torque is transmitted by the center-side assist cam surface 60A or the center-side slipper cam surface 60S, the surface pressure applied to the center-side assist cam surface 60A or the center-side slipper cam surface 60S can be reduced.

[0037] If length L1 is made longer than length L2, the position of the inner diameter end of the center-side assist cam surface 60A at the end of the second direction D2 and the position of the inner diameter end of the center-side slipper cam surface 60S at the end of the second direction D2 may be the same in the radial direction. In this case, the arc AR1, which is centered on axis CL and passes through the midpoint of the radial direction at the end of the center-side assist cam surface 60A in the second direction D2, and the arc, which is centered on axis CL and passes through the midpoint of the radial direction at the end of the center-side slipper cam surface 60S in the second direction D2, will be offset in the radial direction. That is, the arc AR1, which is centered on axis CL and passes through the midpoint of the radial direction at the end of the center-side assist cam surface 60A in the second direction D2, is located on the outer diameter side of the arc, which is centered on axis CL and passes through the midpoint of the radial direction at the end of the center-side slipper cam surface 60S in the second direction D2. The radial length of the center-side assist cam surface 60A at the end in the second direction may be the same as the radial length of the center-side slipper cam surface 60S at the end in the second direction. In this case, when viewed in the direction of the axis CL, the arc AR1 centered on the axis CL and passing through the midpoint of the radial direction at the end of the second direction D2 of the center-side assist cam surface 60A may also pass through the midpoint of the radial direction at the end of the second direction D2 of the center-side slipper cam surface 60S. The main outer peripheral surface 63P (see Figure 3) may be inclined radially inward toward the second direction D2 over its entire length.

[0038] The assist-side cam portion 63A extends further toward the second direction D2 than the slipper-side cam portion 63S. Therefore, as shown in Figure 6, the end 67A of the center-side assist cam surface 60A toward the second direction D2 is located further toward the second direction D2 than the end 67S of the center-side slipper cam surface 60S toward the second direction D2. Also, in direction D, the length L3 of the center-side assist cam surface 60A and the length L4 of the center-side slipper cam surface 60S in direction D are different. Here, length L3 is longer than length L4. Furthermore, as described above, the radial length L1 of the center-side assist cam surface 60A (see Figure 4) is longer than the radial length L2 of the center-side slipper cam surface 60S (see Figure 4). Moreover, as shown in Figure 6, the inclined surface length L5 of the center-side assist cam surface 60A is longer than the inclined surface length L6 of the center-side slipper cam surface 60S. Therefore, the center assist cam surface 60A and the center slipper cam surface 60S have different areas. In this case, the area of ​​the center assist cam surface 60A is larger than that of the center slipper cam surface 60S. However, it is not necessary for all three conditions L1 > L2, L3 > L4, and L5 > L6 to be met; it is acceptable for only one or two of these conditions to be met. Even in such a case, the area of ​​the center assist cam surface 60A can be made larger than that of the center slipper cam surface 60S. In this embodiment, the end 67B of the center assist cam surface 60A on the first direction D1 side and the end 67T of the center slipper cam surface 60S on the first direction D1 side are located at approximately the same position in direction D. However, in order to make the area of ​​the center-side assist cam surface 60A larger than that of the center-side slipper cam surface 60S, the end 67B of the center-side assist cam surface 60A on the first direction D1 side may be positioned further towards the first direction D1 than the end 67T of the center-side slipper cam surface 60S on the first direction D1 side.

[0039] As shown in Figure 3, the main inner surface 63N is formed by the inner surface of the assist-side cam portion 63A and the inner surface of the slipper-side cam portion 63S. The main inner surface 63N is formed across the assist-side cam portion 63A and the slipper-side cam portion 63S. The inner portions of the assist-side cam portion 63A and the slipper-side cam portion 63S are connected to the boss portion 43 and integrated with the boss portion 43. Therefore, at least a part of the assist-side cam portion 63A and at least a part of the slipper-side cam portion 63S are integrated with the boss portion 43. More specifically, the portions of the assist-side cam portion 63A and the slipper-side cam portion 63S on the first direction D1 side are connected to the boss portion 43.

[0040] As shown in Figure 4, an inner circumferential recess 63R is formed between the center cam portion 60 and the boss portion 43. The inner circumferential recess 63R is recessed in the direction toward the second circumferential direction S2, that is, from the center slipper cam surface 60S toward the center assist cam surface 60A. The end of the inner circumferential recess 63R toward the second circumferential direction S2 is located toward the first circumferential direction S1 than the assist cam portion 63A. The inner circumferential surface of the slipper cam portion 63S is radially separated from the boss portion 43.

[0041] As shown in Figure 3, the assist-side cam portion 63A has an assist-side recess 65 that is recessed in the first direction D1. As shown in Figure 4, the assist-side recess 65 is formed in a substantially rectangular shape when viewed from direction D (i.e., in the axial direction of the output shaft 15). The assist-side recess 65 has a shape that tapers towards the first direction D1. The opening area of ​​the cross section (hereinafter referred to as the cross section) of the assist-side recess 65 perpendicular to direction D becomes smaller towards the first direction D1. As shown in Figure 6, the bottom surface 65E of the assist-side recess 65 is located on the first direction D1 side of the slipper-side cam portion 63S end surface 63G on the second direction side.

[0042] As shown in Figure 5, the slipper-side cam portion 63S has a slipper-side recess 66 that is recessed in the second direction D2. The slipper-side recess 66 is formed in a roughly rectangular shape when viewed from direction D. The slipper-side recess 66 has a shape that tapers towards the second direction D2. The opening area of ​​the cross-section of the slipper-side recess 66 becomes smaller towards the second direction D2. As shown in Figure 6, the bottom surface 65E of the assist-side recess 65 is located on the first direction D1 side than the bottom surface 66E of the slipper-side recess 66.

[0043] As shown in Figure 3, the clutch center 40 is provided with a plurality (three in this embodiment) of boss portions 54 for supporting the stopper plate 100 (see Figure 1). The plurality of boss portions 54 are arranged at equal intervals in the circumferential direction S. The boss portions 54 are formed in a cylindrical shape. The boss portions 54 are located radially outward from the output shaft holding portion 50. The boss portions 54 extend toward the pressure plate 70 (see Figure 1) (i.e., toward the second direction D2). The boss portions 54 extend toward the second direction D2 than the assist-side cam portion 63A. Part of the boss portion 54 is provided on the assist-side cam portion 63A, and the other part of the boss portion 54 is provided on the slipper-side cam portion 63S. The boss portion 54 is provided across the assist-side cam portion 63A and the slipper-side cam portion 63S. The boss portion 54 penetrates the clutch center 40 in the axial direction (i.e., direction D). As shown in Figure 5, a portion of the boss portion 54 is provided on the end face 63F of the assist-side cam portion 63A.

[0044] As shown in FIG. 3, the center-side fitting portion 58 is located radially outside the output shaft holding portion 50 and the center-side cam portion 60. The center-side fitting portion 58 is located on the first direction D1 side of the center-side cam portion 60. The center-side fitting portion 58 is connected to the center-side cam portion 60 at the end 58D on the second direction D2 side of the center-side fitting portion 58. The end 58E on the first direction D1 side of the center-side fitting portion 58 is located on the first direction D1 side of the center-side pressing surface 69 of the center-side flange 68 described later. The center-side fitting portion 58 is configured to be slidably fitted inside a pressure-side fitting portion 88 (see FIG. 7) described later. The outer diameter of the center-side fitting portion 58 is formed with a fitting tolerance that allows the flow of oil flowing out from the tip portion 15T (see FIG. 1) of the output shaft 15 (see FIG. 1) with respect to the pressure-side fitting portion 88. That is, a gap is formed between the center-side fitting portion 58 and the pressure-side fitting portion 88 described later. In the present embodiment, for example, the center-side fitting portion 58 is formed with an inner diameter that is, for example, 0.1 mm larger than the outer diameter of the pressure-side fitting portion 88.

[0045] As shown in FIGS. 3 and 4, the clutch center 40 has a center-side cam hole 43H that penetrates a part of the center-side main body portion 42. The center-side cam hole 43H is an example of the through hole in the present invention. The center-side cam hole 43H extends from the side of the boss portion 43 to radially outside the center-side fitting portion 58. Each center-side cam hole 43H is formed between adjacent center-side cam portions 60 in the circumferential direction. As shown in FIG. 5, when viewed from the direction D, a part of the center-side assist cam surface 60A is located inside the center-side cam hole 43H. The center-side cam hole 43H has a substantially fan-shaped shape when viewed from the direction D. As shown in FIG. 4, the boss portion 43 forms an inner edge portion 43Ha that partitions the inside in the radial direction of the center-side cam hole 43H. The position inside the center-side cam hole 43H in the radial direction is located radially inside the center-side cam portion 60.

[0046] As shown in Figure 3, the center recess 59 is formed on the radially outer side of the center fitting portion 58. The center recess 59 is connected to the center fitting portion 58 and the center flange 68. In the radial direction, the center recess 59 is formed between the center fitting portion 58 and the center pressing surface 69 of the center flange 68, which will be described later. The center recess 59 is recessed toward the first direction D1. Also, the center recess 59 is recessed toward the first direction D1 relative to the center pressing surface 69 of the center flange 68. In the circumferential direction S, the center recess 59 is formed at the same position as the center fitting portion 58. Viewed from direction D, the circumferential end of the center recess 59 toward the center cam hole 43H is connected to the center cam hole 43H. As shown in Figure 1, the center recess 59 faces the end face 74D of the annular wall 74A of the pressure plate 70 (described later) and the end face 77B of the pressure-side fitting tooth 77 on the first direction D1 side in direction D. As shown in Figure 4, the radial length of the center recess 59 is L14. In this embodiment, the radial length L14 of the center recess 59 is uniform regardless of the position of the center recess 59 in direction D. However, the radial length of the center recess 59 is not limited to this. For example, the radial length of the center recess 59 may become shorter as it moves towards the first direction D1. The radial length L14 of the center recess 59 is uniform regardless of the position of the center recess 59 in the circumferential direction S. However, the radial length of the center recess 59 is not limited to this. For example, the radial length of the center recess 59 may become shorter as it moves towards the first circumferential direction S1. Furthermore, the center-side recess 59 may, for example, have a portion that penetrates in direction D.

[0047] As shown in Figure 3, the center flange 68 is located radially outward from the center recess 59. The center flange 68 is located radially outward from the center fitting portion 58. The center flange 68 is formed integrally with the center recess 59. The center pressing surface 69, which is the surface of the center flange 68 on the second direction D2 side, sandwiches the input rotating plate 20 (see Figure 1) and the output rotating plate 22 (see Figure 1) between itself and the pressure plate 70 (see Figure 1). The center pressing surface 69 presses the input rotating plate 20 and the output rotating plate 22. The center pressing surface 69 is located on the second direction D2 side of the center recess 59 than the end (bottom surface) of the first direction D1. As shown in Figure 6, in direction D, the length from the center-side pressing surface 69 to the end 67A of the center-side assist cam surface 60A on the second direction D2 side is length L7. Length L7 is longer than the length L15 (see Figure 11) from the pressure-side pressing surface 98A (see Figure 11) to the end face 77B (see Figure 11) of the pressure-side fitting tooth 77 (see Figure 11) (see also Figure 1). Also, as shown in Figure 1, when the pressure plate 70 is closest to the clutch center 40 and the input-side rotating plate 20 and the output-side rotating plate 22 are pressed against each other, length L7 is longer than the length L18 from the center-side pressing surface 69 to the pressure-side pressing surface 98A (see also Figure 1).

[0048] As shown in Figure 1, the pressure plate 70 is provided so as to be able to move toward and away from the clutch center 40 and to be able to rotate relative to it. The pressure plate 70 is configured to be able to press against the input side rotating plate 20 and the output side rotating plate 22. The pressure plate 70 is positioned concentrically with the clutch center 40 and the clutch housing 30. As shown in Figure 7, the pressure plate 70 comprises a pressure side body portion 72, a pressure side recess 85, and a pressure side flange 98. The pressure side flange 98 is connected to the portion of the pressure side body portion 72 on the second direction D2 side and extends radially outward. The pressure side body portion 72 protrudes more than the pressure side flange 98 in the first direction D1. The pressure plate 70 holds a plurality of output side rotating plates 22 (see Figure 1) which are arranged alternately with the input side rotating plate 20 (see Figure 1).

[0049] As shown in FIG. 7, the pressure-side main body portion 72 includes a cylindrical portion 80, an outer peripheral wall 73, a plurality of pressure-side cam portions 90, a pressure-side fitting portion 88, and a spring accommodating portion 84 (see FIG. 8).

[0050] The cylindrical portion 80 is formed in a cylindrical shape. The cylindrical portion 80 is formed integrally with the pressure-side cam portion 90. The cylindrical portion 80 accommodates the tip portion 15T (see FIG. 1) of the output shaft 15. A release bearing 18 (see FIG. 1) is accommodated in the cylindrical portion 80. The cylindrical portion 80 is a portion that receives the pressing force from the push member 16B (see FIG. 1). Further, the cylindrical portion 80 is a portion that receives the oil flowing out from the tip portion 15T of the output shaft 15.

[0051] As shown in FIG. 7, the outer peripheral wall 73 is disposed radially outside the cylindrical portion 80. The outer peripheral wall 73 extends in the first direction D1. The outer peripheral wall 73 has a cylindrical portion 74 formed in a cylindrical shape centered on the axis of the output shaft 15 (see FIG. 1) and a protruding portion 75. The cylindrical portion 74 has an annular wall 74A and a spline fitting portion 74B provided on the radially outer side of the annular wall 74A. The spline fitting portion 74B has a plurality of pressure-side fitting teeth 77 extending in the direction D, a plurality of spline grooves 78 formed between adjacent pressure-side fitting teeth 77, a plurality of tooth missing portions 76 formed between adjacent pressure-side fitting teeth 77, and an oil discharge hole 79. The tooth missing portion 76 has a longer length in the circumferential direction S than the spline groove 78. The pressure-side fitting teeth 77 hold the output-side rotating plate 22 (see FIG. 1). The plurality of pressure-side fitting teeth 77 are arranged in the circumferential direction S. The pressure-side fitting teeth 77 protrude radially outward from the annular wall 74A. No pressure-side fitting teeth 77 are provided in the tooth missing portion 76. Therefore, the circumferential interval in the circumferential direction S between two pressure-side fitting teeth 77 arranged in the circumferential direction S sandwiching the tooth missing portion 76 is longer than the circumferential interval in the circumferential direction S between two pressure-side fitting teeth 77 arranged in the circumferential direction S sandwiching the spline groove 78. In the present embodiment, the tooth missing portions 76 are provided at three equal intervals along the circumferential direction S.

[0052] The oil discharge hole 79 is formed to penetrate the toothless portion 76 radially. The oil discharge hole 79 connects the inside and outside of the pressure plate 70. The oil discharge hole 79 is a hole that discharges oil that has flowed into the pressure plate 70 from the output shaft 15 (see Figure 1) to the outside of the pressure plate 70. In this embodiment, four oil discharge holes 79 are formed in the toothless portion 76. The four oil discharge holes will also be referred to as oil discharge holes 79L, 79M, 79N1, and 79N2. However, when giving a description common to all of the oil discharge holes 79L, 79M, 79N1, and 79N2, the name oil discharge hole 79 will be used as appropriate. The oil discharge hole 79L, oil discharge hole 79M, and oil discharge holes 79N1 and 79N2 are each formed in one of the three aligned toothless portions 76. The oil discharge hole 79 is located close to the pressure-side assist cam surface 90A on the first circumferential direction S1 side. For example, the distance in the circumferential direction S between the pressure-side assist cam surface 90A, which is located on the second circumferential direction S2 side of the oil discharge hole 79L, and the oil discharge hole 79L is shorter than the distance in the circumferential direction S between the pressure-side slipper cam surface 90S, which is located on the first circumferential direction S1 side of the oil discharge hole 79L, and the oil discharge hole 79L. The same applies to the oil discharge holes 79M, 79N1, and 79N2. The number of oil discharge holes 79 formed in a single toothless portion 76 is not particularly limited. For example, two or more oil discharge holes 79 may be formed in a single toothless portion 76 at positions close to the pressure-side assist cam surface 90A.

[0053] As shown in Figure 11, the oil discharge hole 79L overlaps with the first direction D1 end 95B of the pressure-side assist cam surface 90A in direction D. As shown in Figure 7, the oil discharge holes 79L, 79M, 79N1, and 79N2 are formed at positions offset from each other in direction D. However, the position of the oil discharge holes 79 in direction D is not particularly limited. Some of the oil discharge holes 79 may be aligned with each other in direction D, or all of the oil discharge holes 79 may be aligned with each other in direction D. The oil discharge holes 79L, 79M, and 79N1 are arranged at approximately equal intervals along the circumferential direction S. However, the oil discharge holes 79 do not have to be arranged at approximately equal intervals along the circumferential direction S. Some of the pressure-side fitting teeth 77 are arranged at equal intervals. For example, the pressure-side fitting teeth 77 arranged between the oil discharge hole 79L and the oil discharge hole 79M are arranged at equal intervals.

[0054] As shown in Figures 7 and 8, the pressure-side main body portion 72 has through holes 89 located in the missing tooth portion 76 and penetrating in direction D. Three through holes 89 are arranged at equal intervals in the circumferential direction S (see also Figure 10). In plan view, the through holes 89 are formed in the same shape as the pressure-side mating teeth 77. Therefore, the radial length and circumferential length S of the through holes 89 are formed in the same way as the radial length and circumferential length S of the pressure-side mating teeth 77. As shown in Figure 8, the through holes 89 are formed in a substantially trapezoidal shape when viewed from direction D. More specifically, the circumferential length S of the radially inner edge 89a of the through hole 89 is longer than the circumferential length S of the radially outer edge 89b of the through hole 89 (see also Figure 14). Furthermore, as shown in Figure 7, the spacing between adjacent through holes 89 and pressure-side fitting teeth 77 in the circumferential direction S is equal to the spacing between two adjacent pressure-side fitting teeth 77 in the circumferential direction S, separated by a spline groove 78 (see also Figure 10). The through holes 89 are formed in the circumferential direction S at a position that overlaps with at least a portion of the oil discharge holes 79. Therefore, a portion of the oil that flows out from the oil discharge holes 79 lubricates the input-side rotating plate 20 and the output-side rotating plate 22, then passes through the through holes 89 and is discharged to the outside of the pressure plate 70.

[0055] As shown in Figure 7, the pressure plate 70 has a projection 75 that extends in the first direction D1 from the cylindrical portion 74, specifically from the pressure-side fitting teeth 77, and from the end face of the cylindrical portion 74 on the first direction D1 side, specifically from the end face 77B of the pressure-side fitting teeth 77 on the first direction D1 side. The projection 75 is connected to the end face 77B of some of the pressure-side fitting teeth 77 on the first direction D1 side. The end face 77B of the pressure-side fitting teeth 77 on the first direction D1 side refers to the end face on the first direction D1 side of the pressure-side fitting teeth 77 to which the projection 75 is not connected. In this embodiment, the end face 74D of the annular wall 74A on the first direction D1 side and the end face 77B of the pressure-side fitting teeth 77 on the first direction D1 side are flush. Therefore, "the end face of the cylindrical portion 74 on the first direction D1 side" refers to the end face 74D of the annular wall 74A and the end face 77B of the pressure-side fitting tooth 77. However, if the end face 74D of the annular wall 74A and the end face 77B of the pressure-side fitting tooth 77 are offset from each other in direction D, then "the end face of the cylindrical portion 74 on the first direction D1 side" refers to the end face of the annular wall 74A and the end face 77B of the pressure-side fitting tooth 77 that is located on the first direction D1 side. Figure 9 is an enlarged view of the vicinity of the protruding portion 75 in Figure 1. As shown in Figure 9, the annular wall 74A includes a first annular portion 74A1 that forms part of the spring housing portion 84 described later, and a second annular portion 74A2 that extends from the first annular portion 74A1 toward the first direction D1 side. The second annular portion 74A2 is connected to the end of the first annular portion 74A1 on the first direction D1 side and extends further toward the first direction D1 side than the first annular portion 74A1. Pressure-side mating teeth 77 are formed on the first annular portion 74A1 and the second annular portion 74A2. The position of the end face 77B of the pressure-side mating teeth 77 on the first direction D1 side (see also Figure 1) is the same as the position of the end of the second annular portion 74A2 on the first direction D1 side. The position of the end face 77A of the pressure-side mating teeth 77 on the second direction D2 side is the same as the position of the end of the first annular portion 74A1 on the second direction D2 side. As shown in Figure 9, the inner circumferential surface 74C1 of the first annular portion 74A1 is located radially inward than the inner circumferential surface 74C2 of the second annular portion 74A2.As shown in Figure 9, the radial thickness H1 of the first annular portion 74A1 is greater than the radial thickness H2 of the second annular portion 74A2.

[0056] As shown in Figure 7, the protrusions 75 are formed to protrude in the first direction D1 from the end face 77B of the pressure-side fitting teeth 77 and the end face 74D of the annular wall 74A (i.e., the end face of the cylindrical portion 74 on the first direction D1 side). As shown in Figure 10, the protrusions 75 are formed at three locations in the circumferential direction S. The protrusions 75 are arranged at equal intervals in the circumferential direction S. When the clutch center 40 (see Figure 3) and the pressure plate 70 are assembled (see also Figure 16), at least a portion of the protrusions 75 are positioned inside the center-side cam hole 43H (see Figure 5) when viewed from direction D. The protrusions 75 may be formed separately from the cylindrical portion 74. The outer peripheral wall 73 has three protrusions 75, but the number of protrusions 75 is not limited to three. Also, the protrusions 75 do not have to be arranged at equal intervals in the circumferential direction S. The projection 75 may be connected across the end face 74D of the annular wall 74A on the first direction D1 side shown in Figure 7 and the end face 77B of the pressure-side fitting tooth 77 on the first direction D1 side, or it may be connected only to the end face 74D of the annular wall 74A on the first direction D1 side. Furthermore, the radial and circumferential lengths of the end face of the projection 75 on the second direction D2 side are the same as the radial and circumferential lengths of the end face 77B of the pressure-side fitting tooth 77 on the first direction D1 side, but they do not necessarily have to be the same. That is, the radial and / or circumferential lengths of the end face of the projection 75 on the second direction D2 side may be shorter than the radial and / or circumferential lengths of the end face 77B of the pressure-side fitting tooth 77 on the first direction D1 side, so that a step is formed between the end face of the projection 75 on the second direction D2 side and the end face 77B of the pressure-side fitting tooth 77 on the first direction D1 side.

[0057] The projection 75 extends toward the first direction D1 and is a member having a substantially pyramidal shape when viewed from direction D (see also Figure 11). The projection 75 has a shape that tapers towards the first direction D1. As shown in Figure 9, the projection 75 has a slope 75S1. The slope 75S1 forms the radially outer circumferential surface of the projection 75. The slope 75S1 extends from the end face 77B of the pressure-side fitting tooth 77 toward the first direction D1 toward the end face 75A of the projection 75 toward the first direction D1. The slope 75S1 extends radially inward toward the first direction D1 and is inclined with respect to the axial direction. The projection 75 is formed in a shape in which the radial length becomes shorter toward the first direction D1. Also, as shown in Figure 10, the projection 75 has slopes 75S2 and 75S3. The inclined surfaces 75S2 and 75S3 extend from the end face 77B of the pressure-side fitting tooth 77 (see Figure 9) on the first direction D1 side toward the end face 75A of the projection 75 (see Figure 9). The inclined surface 75S2 is located on the first circumferential direction S1 side with respect to the end face 75A of the projection 75. The inclined surface 75S3 is located on the second circumferential direction S2 side with respect to the end face 75A of the projection 75. The projection 75 is formed in a shape in which the length in the circumferential direction S becomes shorter as it approaches the first direction D1 (see also Figure 7). In this embodiment, the end face 75A of the projection 75 is located inside the center-side cam hole 43H (see Figure 16). However, the end face 75A of the projection 75 may be located on the first direction D1 side of the center-side cam hole 43H. As shown in Figure 7, the circumferential length of one projection 75 is formed to be approximately the same as that of one pressure-side mating tooth 77.

[0058] As shown in Figure 2, when the rotational axes of the clutch housing 30, the output rotating plate 22, and the pressure plate 70 are located coaxially (i.e., on the axis CL (see Figure 1)), the radial distance between the edge of the inclined surface 75S1 on the first direction D1 side (see also Figure 9) and the inner peripheral edge 22N of the output rotating plate 22 is distance L21. Distance L21 is longer than the radial distance L20 between the inner peripheral surface 33N of the side wall 33 (see Figure 1) and the outer peripheral edge 22U of the output rotating plate 22. Note that it is not necessary for L21 > L20 to hold for all of the multiple output rotating plates 22. At a minimum, it is sufficient that L21 > L20 holds between the output rotating plate 22 located furthest towards the first direction D1 and the side wall 33. The radial distance between the outer circumferential surface 77U of the pressure-side mating teeth 77 and the inner circumferential edge 22N of the output-side rotating plate 22 is length L22. Length L22 is shorter than the radial distance L20 between the inner circumferential surface 33N of the side wall 33 and the outer circumferential edge 22U of the output-side rotating plate 22, as shown in Figure 2.

[0059] As shown in Figure 10, the circumferential length S of one projection 75 is W1. In this embodiment, the pressure plate 70 has three projections 75, so the total length obtained by summing the circumferential lengths S of the projections 75 is 3 × W1. Here, let W2 be the length of half the circumference of the annular wall 74A. In this case, the total length 3 × W1 obtained by summing the circumferential lengths S of the projections 75 is shorter than the length W2 of half the circumference of the cylindrical portion 74.

[0060] The pressure-side cam portion 90 shown in Figure 7 is formed in a trapezoidal shape with cam surfaces 90A and 90S that are inclined surfaces. The pressure-side cam portion 90, together with the center-side cam portion 60 (see Figure 3), forms an assist & slipper (registered trademark) mechanism that slides against each other to generate assist torque or slipper torque. The pressure-side cam portion 90 protrudes from the pressure-side flange 98 in the first direction D1. The pressure-side cam portions 90 are arranged at equal intervals in the circumferential direction S of the pressure plate 70. In this embodiment, the pressure plate 70 has three pressure-side cam portions 90, but the number of pressure-side cam portions 90 is not limited to three.

[0061] The pressure-side cam portion 90 is located radially outward from the cylindrical portion 80. The pressure-side cam portion 90 includes a pressure-side assist cam portion 91 including a pressure-side assist cam surface 90A, a pressure-side slipper cam portion 92 including a pressure-side slipper cam surface 90S, and a pressure-side cam body portion 93 located between the pressure-side assist cam portion 91 and the pressure-side slipper cam portion 92. The pressure-side assist cam portion 91, the pressure-side cam body portion 93, and the pressure-side slipper cam portion 92 are integrally formed. In this embodiment, the pressure plate 70 rotates in the direction from the pressure-side cam body portion 93 toward the pressure-side assist cam portion 91 (i.e., the first circumferential direction S1). The pressure-side cam body portion 93 is located on the opposite side of the rotation direction of the pressure plate 70 (i.e., the first circumferential direction S1) from the pressure-side assist cam portion 91. The pressure-side cam body portion 93 is located relative to the pressure-side slipper cam portion 92 on the side of the rotational direction of the pressure plate 70 (i.e., the first circumferential direction S1). The pressure-side assist cam surface 90A is configured to be in contact with the center-side assist cam surface 60A (see Figure 3). The pressure-side assist cam surface 90A is configured to generate a force that moves the pressure plate 70 closer to the clutch center 40 in order to increase the pressing force (contact force) between the input-side rotating plate 20 (see Figure 1) and the output-side rotating plate 22 (see Figure 1) when the pressure plate 70 rotates relative to the clutch center 40 (see Figure 3). The pressure-side assist cam surface 90A extends toward the first circumferential direction S1 as it moves toward the first direction D1, and is inclined with respect to the axial direction. The pressure-side slipper cam surface 90S is configured to be in contact with the center-side slipper cam surface 60S (see Figure 3). The pressure-side slipper cam surface 90S is configured to generate a force that separates the pressure plate 70 from the clutch center 40 in order to reduce the pressing force (contact force) between the input-side rotating plate 20 and the output-side rotating plate 22 when the pressure plate 70 rotates relative to the clutch center 40.In adjacent pressure-side cam portions 90 with respect to the circumferential direction S, the pressure-side assist cam surface 90A of one pressure-side cam portion 90L and the pressure-side slipper cam surface 90S of the other pressure-side cam portion 90M are arranged opposite each other in the circumferential direction S. The pressure-side slipper cam surface 90S is located on the opposite side of the pressure-side assist cam surface 90A, with the pressure-side cam body portion 93 in between. The pressure-side slipper cam surface 90S extends toward the first circumferential direction S1 as it moves toward the first direction D1, and is inclined with respect to the axial direction.

[0062] As shown in Figure 7, a main inner surface 93N is formed on the pressure-side cam body 93. A sub-inner surface 91A is formed on the pressure-side cam portion 90. The sub-inner surface 91A is connected to the pressure-side assist cam surface 90A. The sub-inner surface 91A extends radially inward as it moves toward the first direction D1 and is inclined with respect to the axial direction. That is, the sub-inner surface 91A is inclined to move radially outward from the main inner surface 93N as it moves toward the second direction D2. The sub-inner surface 91A may also be parallel to the axis of the output shaft 15. Of the main inner surface 93N, at least the side facing the sub-inner surface 91A (i.e., the side facing the first circumferential direction S1) is inclined to move radially inward from the sub-inner surface 91A as it moves toward the second direction D2. Therefore, the radial length of the pressure-side assist cam surface 90A increases as it moves toward the first direction D1. Here, as shown in Figure 10, the longest radial length of the pressure-side assist cam surface 90A is defined as length L8. The longest radial length of the pressure-side slipper cam surface 90S is defined as length L9. Length L8 is the same as length L9. The midpoint in the radial direction at the end of the first direction D1 of the pressure-side assist cam surface 90A coincides with the midpoint in the radial direction at the end of the first direction D1 of the pressure-side slipper cam surface 90S. The arc AR3, centered on axis CL and passing through the midpoint in the radial direction at the end of the first direction D1 of the pressure-side assist cam surface 90A, also passes through the midpoint in the radial direction at the end of the first direction D1 of the pressure-side slipper cam surface 90S. Note that lengths L8 and L9 may be different. Length L8 may be longer than length L9. If length L8 is longer than length L9, the inner diameter end of the pressure-side assist cam surface 90A at the end of the first direction D1 may be positioned on the inner diameter side of the pressure-side slipper cam surface 90S at the end of the first direction D1.In this case, the arc AR3, which is centered on axis CL and passes through the midpoint in the radial direction at the end of the first direction D1 of the pressure-side assist cam surface 90A, and the arc, which is centered on axis CL and passes through the midpoint in the radial direction at the end of the first direction D1 of the pressure-side slipper cam surface 90S, may be offset in the radial direction. That is, the arc AR3, which is centered on axis CL and passes through the midpoint in the radial direction at the end of the first direction D1 of the pressure-side assist cam surface 90A, may be located on the inner diameter side of the arc, which is centered on axis CL and passes through the midpoint in the radial direction at the end of the first direction D1 of the pressure-side slipper cam surface 90S. The radial length of the end of the first direction D1 of the pressure-side assist cam surface 90A may be the same as the radial length of the end of the first direction D1 of the pressure-side slipper cam surface 90S. In this case, when viewed in the direction of the axis CL, the arc AR3, centered on the axis CL and passing through the midpoint in the radial direction at the end of the first direction D1 of the pressure-side assist cam surface 90A, may also pass through the midpoint in the radial direction at the end of the first direction D1 of the pressure-side slipper cam surface 90S.

[0063] As shown in Figure 12, the pressure-side assist cam surface 90A extends in direction D to the second direction D2 side beyond the pressure-side flange 98. More specifically, the pressure-side assist cam surface 90A extends to the second direction D2 side beyond the outer surface 98B, which will be described later. That is, the end 95 of the pressure-side assist cam surface 90A on the second direction D2 side is located on the second direction D2 side beyond the pressure-side flange 98. As described above, the pressure-side fitting teeth 77 are provided on the pressure-side main body portion 72 which extends in the first direction D1 side beyond the pressure-side flange 98. Therefore, the end 95 of the pressure-side assist cam surface 90A is located on the second direction D2 side beyond the end face 77A of the pressure-side fitting teeth 77 on the second direction D2 side. Furthermore, as shown in Figure 1, the end 95 of the pressure-side assist cam surface 90A on the second direction D2 side is located on the second direction D2 side of the input-side rotating plate 20A, which is the input-side rotating plate 20 located furthest to the second direction D2 among the input-side rotating plates 20, and the outermost output-side rotating plate 22A, which is the output-side rotating plate 22 located furthest to the second direction D2 among the output-side rotating plates 22. That is, the end 95 of the pressure-side assist cam surface 90A is located on the second direction D2 side of the rotating plate (output-side rotating plate 22 in Figure 1) located furthest to the second direction D2 among the multiple input-side rotating plates 20 and multiple output-side rotating plates 22. On the other hand, as shown in Figure 12, the pressure-side slipper cam surface 90S is located on the first direction D1 side of the pressure-side flange 98 in direction D. Therefore, the end 95 of the pressure-side assist cam surface 90A is located on the second direction D2 side of the pressure-side slipper cam surface 90S than the end 96 on the second direction D2 side. Also, the end 95 of the pressure-side assist cam surface 90A is connected to the end surface 90D (see Figure 8) of the pressure-side cam portion 90 on the second direction D2 side. In other words, the end 95 of the pressure-side assist cam surface 90A is the end of the pressure-side cam portion 90 on the second direction D2 side.

[0064] In direction D, the length L10 of the pressure-side assist cam surface 90A and the length L11 of the center-side slipper cam surface 60S are different. Here, length L10 is longer than length L11. Also, as shown in Figure 12, the length L12 of the pressure-side assist cam surface 90A in the inclined surface direction is longer than the length L19 of the pressure-side slipper cam surface 90S in the inclined surface direction. Therefore, the areas of the pressure-side assist cam surface 90A and the pressure-side slipper cam surface 90S are different. Here, the area of ​​the pressure-side assist cam surface 90A is larger than that of the pressure-side slipper cam surface 90S. However, it is not necessary for both conditions L10 > L11 and L12 > L19 to be met; only one of the conditions may be met. Even in such a case, the area of ​​the pressure-side assist cam surface 90A can be made larger than the area of ​​the pressure-side slipper cam surface 90S. In this embodiment, the end 95B of the pressure-side assist cam surface 90A on the first direction D1 side and the end 96B of the pressure-side slipper cam surface 90S on the first direction D1 side are located in approximately the same position in direction D. However, in order to make the area of ​​the pressure-side assist cam surface 90A larger than that of the pressure-side slipper cam surface 90S, the end 95B of the pressure-side assist cam surface 90A on the first direction D1 side may be positioned closer to the first direction D1 than the end 96B of the pressure-side slipper cam surface 90S on the first direction D1 side.

[0065] Here, the operation of the center-side cam portion 60 (see Figure 3) and the pressure-side cam portion 90 will be explained. When the engine speed increases and the clutch is turned ON, the push member 16B shown in Figure 1 moves to the first direction D1, and the input-side rotating plate 20 and the output-side rotating plate 22 are pressed against each other, and the rotational driving force of the input shaft is transmitted to the output shaft 15. At this time, the pressure plate 70 is in the state where it has moved to the first direction D1, that is, the state where it is closest to the clutch center 40. Also at this time, the center-side assist cam surface 60A of the center-side cam portion 60 (see Figure 3) and the pressure-side assist cam surface 90A of the pressure-side cam portion 90 (see Figure 7) are in contact with each other. When the clutch is ON, the rotational driving force input to the input gear 35 and clutch housing 30 shown in Figure 1 can be transmitted to the output shaft 15 via the clutch center 40. At this time, as shown in Figure 13A, a first rotational force in the circumferential direction S1 is applied to the pressure plate 70. As a result, due to the action of the center-side assist cam surface 60A and the pressure-side assist cam surface 90A, a force in the first direction D1 is generated on the pressure plate 70. This increases the pressure contact force between the input-side rotating plate 20 and the output-side rotating plate 22.

[0066] On the other hand, when the rotational speed of the output shaft 15 shown in Figure 1 exceeds the rotational speed of the input gear 35 and the clutch housing 30, back torque is generated. In this case, as shown in Figure 13B, a first circumferential rotational force S1 is applied to the clutch center 40. As a result, the contact force between the input side rotating plate 20 (see Figure 1) and the output side rotating plate 22 (see Figure 1) is released by the action of the center side slipper cam surface 60S and the pressure side slipper cam surface 90S. This makes it possible to avoid malfunctions in the engine and transmission caused by back torque.

[0067] As shown in Figure 7, the pressure-side fitting portion 88 is located radially outward from the pressure-side cam portion 90. The pressure-side fitting portion 88 is located on the first direction D1 side of the pressure-side cam portion 90. As shown in Figure 9, the pressure-side fitting portion 88 is the portion of the second annular portion 74A2 of the annular wall 74A that extends from the end on the first direction D1 side to the second direction D2. The second annular portion 74A2 extends from the bottom surface 84A of the spring housing portion 84, which will be described later, to the first direction D1 side. The spring housing portion 84 houses the clutch spring 25, which will be described later. Therefore, the pressure-side fitting portion 88 is located on the first direction D1 side of the bottom surface 84A of the spring housing portion 84 and the end 25A of the clutch spring 25 on the first direction D1 side. The pressure-side fitting portion 88 is configured to be externally fitted to the center-side fitting portion 58 so as to be slidable in direction D. The cylindrical portion 74 is externally fitted to the center-side fitting portion 58. However, the pressure-side fitting portion 88 may also be internally fitted to the center-side fitting portion 58.

[0068] In the radial direction of the pressure plate 70, the length from the spline groove 78 (see Figure 9) to the outer circumferential surface 77U of the pressure-side fitting teeth 77, i.e., the height of the pressure-side fitting teeth 77, is length L13. The radial length of the cylindrical portion 74 is length L26. The radial length L14 of the center-side recess 59 is longer than lengths L13 and L26.

[0069] As shown in Figure 14, a spring-side recess 94 is formed in the pressure-side cam portion 90. The spring-side recess 94 is formed on the second direction D2 side of the pressure-side slipper cam surface 90S of the pressure-side cam portion 90 (see also Figure 8). The spring-side recess 94 is formed in connection with the pressure-side cam hole 73H, which will be described later, and the spring housing portion 84, which will be described later. The spring-side recess 94 is connected to the spring housing portion 84 on the first circumferential direction S1 side and to the pressure-side cam hole 73H on the second circumferential direction S2 side. The spring-side recess 94 has a shape that is cut out from the end face 90D on the second direction D2 side of the pressure-side cam portion 90 toward the first direction D1 side, and is a recessed portion toward the first direction D1 side. The radial length of the spring-side recess 94 is formed to be shorter than the radial length of the spring housing portion 84, which will be described later. Furthermore, the length of the spring-side recess 94 in direction D is less than half the length of the clutch spring 25 in direction D, which will be described later.

[0070] As shown in Figure 7, the pressure-side recess 85 is formed radially outward from the outer edge of the outer peripheral wall 73. The pressure-side recess 85 is connected to the outer peripheral wall 73 and the pressure-side flange 98. The pressure-side recess 85 is recessed toward the second direction D2 side than the pressure-side pressing surface 98A of the pressure-side flange 98, which will be described later. The pressure-side recess 85 is formed over the circumferential direction S. As shown in Figure 1, a judder spring 120 is housed in the pressure-side recess 85. The judder spring 120 is held by the pressure plate 70. The inner peripheral edge of the judder spring 120 abuts against the outer peripheral surface of the pressure-side mating teeth 77 and is held by the pressure-side mating teeth 77. The judder spring 120 is held so as to be movable relative to the pressure-side mating teeth 77 in direction D and relative to the circumferential direction S. The judder spring 120 is aligned in direction D with the output-side rotating plate 22 held by the pressure plate 70. The judder spring 120 is provided so as to be in contact with the output-side rotating plate 22 held by the pressure plate 70. In this embodiment, the judder spring 120 is positioned between the outermost output-side rotating plate 22A of the output-side rotating plates 22 held by the pressure plate 70 and the pressure-side flange 98. An iron sheet material 122 is positioned between the judder spring 120 and the pressure-side flange 98. As a result, the judder spring 120 does not directly contact the pressure-side flange 98, thereby suppressing wear of the pressure-side flange 98, which is made of aluminum alloy. The judder spring 120 may be, for example, a disc spring or a wave spring.

[0071] As shown in Figure 7, the pressure-side flange 98 is connected to the pressure-side recess 85 and is located radially outward from the pressure-side body portion 72. The pressure-side flange 98 is integrally formed with the pressure-side body portion 72 and the pressure-side recess 85. That is, the pressure-side flange 98 is connected to the pressure-side body portion 72 via the pressure-side recess 85. The pressure-side pressing surface 98A, which is the surface of the pressure-side flange 98 on the first direction D1 side, presses against the output-side rotating plate 22 (see Figure 1). The outer surface 98B (see Figure 11), which is the surface of the pressure-side flange 98 on the second direction D2 side, is formed parallel to the pressure-side pressing surface 98A in direction D. As shown in Figure 11, the length from the pressure-side pressing surface 98A to the end face 77B of the pressure-side fitting tooth 77 on the first direction side in direction D is length L15. The pressure-side flange 98 may also be directly connected to the pressure-side main body 72.

[0072] As shown in Figure 14, the pressure plate 70 has a pressure-side cam hole 73H that penetrates a part of the pressure-side main body portion 72 in direction D. The pressure-side cam hole 73H is located radially outward from the cylindrical portion 80. The pressure-side cam hole 73H is formed between the pressure-side assist cam surface 90A and the pressure-side slipper cam surface 90S of adjacent pressure-side cam portions 90. As shown in Figure 14, when viewed from direction D, a part of the pressure-side assist cam surface 90A is located inside the pressure-side cam hole 73H. The pressure-side cam hole 73H has a first portion 73HA and a second portion 73HB. The first portion 73HA is located on the first circumferential direction S1 side of the pressure-side cam hole 73H from a position approximately midway in the circumferential direction S. The second portion 73HB is located on the second circumferential direction S2 side of the first portion 73HA. The first portion 73HA has a radially inner edge 74N and a radially outer edge 74U. In the radial direction, the distance between edge 74N and edge 74U is length L16. The second portion 73HB has a radially inner edge 75N and a radially outer edge 75U. In the radial direction, the distance between edge 75N and edge 75U is length L17. Edge 75N of the second portion 73HB is located inward of edge 74N of the first portion 73HA in the radial direction of the pressure plate 70. Edge 75U of the second portion 73HB is located outward of edge 74N of the first portion 73HA in the radial direction of the pressure plate 70. Therefore, the radial length L17 of the second portion 73HB is longer than the radial length L16 of the first portion 73HA.

[0073] As shown in Figures 8 and 14, the spring housing portion 84 is formed in a cylindrical shape that is recessed in the first direction D1 from the end face 90D of the pressure-side cam portion 90. As shown in Figure 9, the inner circumferential surface 74C1 of the first annular portion 74A1 constitutes the portion of the inner circumferential surface of the spring housing portion 84 that is located radially outward. The spring housing portion 84 is formed in a substantially circular shape when viewed from direction D (see Figure 14). The spring housing portion 84 is the portion that houses the clutch spring 25. As shown in Figure 14, the spring housing portion 84 is connected to the spring-side recess 94. As described above, the spring-side recess 94 has a shape that is cut out toward the first direction D1. Therefore, the portion of the spring housing portion 84 that is connected to the spring-side recess 94 is formed to be shorter in length in direction D compared to the other portions of the spring housing portion 84. The spring housing portion 84 is connected to the pressure-side cam hole 73H via the spring-side recess 94. As shown in Figure 9, the spring housing portion 84 has a bottom surface 84A. The bottom surface 84A is located on the side of the first direction D1 than the intermediate position 77P in direction D of the pressure-side mating teeth 77.

[0074] The clutch spring 25 is housed in the spring housing 84. The clutch spring 25 biases the pressure plate 70 toward the clutch center 40 (i.e., toward the first direction D1). The clutch spring 25 is, for example, a coil spring made of spring steel wound in a spiral shape. The end 25A of the clutch spring 25 toward the first direction D1 is in contact with the bottom surface 84A of the spring housing 84. This biases the pressure plate 70 toward the clutch center 40.

[0075] As shown in Figure 1, the first spring 130A and the second spring 130B are expandable and contractible relative to direction D and are held by the pressure plate 70. In this embodiment, as shown in Figures 15A and 15B, the first spring 130A and the second spring 130B are, for example, wave springs, but are not limited to wave springs and may be elastic members such as rubber or springs such as disc springs. As shown in Figure 1, the first spring 130A is positioned between adjacent output-side rotating plates 22 held by the pressure plate 70. The first spring 130A is provided so as to be in contact with the output-side rotating plates 22 held by the pressure plate 70. Here, as shown in Figure 9, the output-side rotating plate 22 held by the pressure plate 70 that is in contact with the first spring 130A and is located on the first direction D1 side of the first spring 130A is referred to as the output-side rotating plate 22PA. The input side rotating plate 20, which is adjacent to the output side rotating plate 22PA and located on the second direction D2 side of the output side rotating plate 22PA, is designated as the input side rotating plate 20PA. The first spring 130A is configured to prevent the output side rotating plate 22PA and the input side rotating plate 20PA from coming into contact when the center side assist cam surface 60A (see Figure 1) and the pressure side assist cam surface 90A (see Figure 1) come into contact (for example, when the clutch has moved from a disengaged state to a partial clutch state). That is, the first spring 130A creates a gap between the output side rotating plate 22PA and the input side rotating plate 20PA when the center side assist cam surface 60A and the pressure side assist cam surface 90A come into contact. The term "half-clutch state" refers to a state in which the driver operates the clutch by gripping the clutch lever or pressing a shift button, causing slippage between the input-side rotating plate 20 and the output-side rotating plate 22, and the rotational driving force transmitted from the input shaft to the output shaft 15 (see Figure 1) is greater than 0% but less than 100% of the rotational driving force transmitted to the input shaft. The term "at least a part of the half-clutch state" refers to, for example, the region in which the rotational driving force transmitted from the input shaft to the output shaft 15 is greater than 0% but 50% or less (for example, 80% or less) of the rotational driving force transmitted to the input shaft.When the center-side assist cam surface 60A and the pressure-side assist cam surface 90A come into contact, the output-side rotating plate 22, which is located on the second direction D2 side of the output-side rotating plate 22PA, and the input-side rotating plate 20, which is located between them, are pressed against each other, allowing power to be transmitted from the input-side rotating plate 20 to the output-side rotating plate 22. The first spring 130A gradually releases, for example, the clutch lever held by the driver, and when the set load of the clutch spring 25 exceeds the set load of the first spring 130A, it allows contact between the output-side rotating plate 22PA and the input-side rotating plate 20PA.

[0076] The second spring 130B is positioned between the output-side rotating plate 22 held by the pressure plate 70 and the pressure plate 70. The second spring 130B is positioned between adjacent output-side rotating plates 22 held by the pressure plate 70. The second spring 130B is held by the pressure plate 70 and is provided to be in contact with the output-side rotating plate 22 located furthest towards the second direction D2 and the output-side rotating plate 22 located further towards the first direction D1. Here, the output-side rotating plate 22 held by the pressure plate 70 that is in contact with the second spring 130B and located further towards the first direction D1 than the second spring 130B is referred to as the output-side rotating plate 22PB. The input-side rotating plate 20 adjacent to the output-side rotating plate 22PB and located further towards the second direction D2 than the output-side rotating plate 22PB is referred to as the input-side rotating plate 20PB. The second spring 130B is configured to prevent contact between the output-side rotating plate 22PB and the input-side rotating plate 20PB when the center-side assist cam surface 60A and the pressure-side assist cam surface 90A come into contact. That is, the second spring 130B creates a gap between the output-side rotating plate 22PB and the input-side rotating plate 20PB when the center-side assist cam surface 60A and the pressure-side assist cam surface 90A come into contact. The second spring 130B allows contact between the output-side rotating plate 22PB and the input-side rotating plate 20PB when, for example, the driver gradually releases the clutch lever they are holding and the set load of the clutch spring 25 exceeds the set load of the second spring 130B. Note that the clutch device 10 (see Figure 1) may be equipped with only one of the first spring 120A and the second spring 130B.

[0077] In the above configuration, since the contact between at least a portion of the output-side rotating plate 22 held by the pressure plate 70 and the input-side rotating plate 20 is suppressed, it is possible to suppress the sudden application of cam thrust to the input-side rotating plate 20 and the output-side rotating plate 22. As a result, it is possible to suppress a sudden increase in the contact force between the input-side rotating plate 20 and the output-side rotating plate 22.

[0078] Figure 16 shows the clutch center 40 and the pressure plate 70 assembled. In the state shown in Figure 16, the pressure-side fitting portion 88 (see Figure 7) is fitted onto the center-side fitting portion 58 (see Figure 3). At this time, the pressure-side assist cam surface 90A and the center-side assist cam surface 60A are in contact. When the pressure-side assist cam surface 90A and the center-side assist cam surface 60A are in contact, the pressure plate 70 is positioned closest to the first direction D1. As shown in Figure 16, when the clutch center 40 and the pressure plate 70 are assembled, at least a portion of the spline groove 78 is positioned to overlap with the center-side cam hole 43H when viewed from direction D (here, the first direction D1). At this time, when viewed from direction D, the protruding portion 75 of the pressure plate 70 is positioned inside the center-side cam hole 43H. In this embodiment, all of the protrusions 75 are located inside the center-side cam hole 43H, but a portion of the protrusions 75 may also be located inside the center-side cam hole 43H.

[0079] When the pressure-side assist cam surface 90A and the center-side assist cam surface 60A are in contact, as shown in Figure 9, the end face 75A of the protrusion 75 on the first direction D1 side is located on the first direction D1 side of the center-side pressing surface 69. Therefore, a portion of the protrusion 75 is located on the first direction D1 side of the center-side pressing surface 69, and the other portion of the protrusion 75 is located on the second direction D2 side of the center-side pressing surface 69. In other words, a portion of the protrusion 75, which is part of the outer peripheral wall 73, is positioned to overlap with a portion of the center-side recess 59 in the radial direction. Also, a portion of the protrusion 75 overlaps with the center-side cam hole 43H in the radial direction. Since the center-side recess 59 is located on the first direction D1 side of the center-side cam portion 60 (see Figure 3) and the center-side fitting portion 58, as shown in Figure 1, a part of the outer peripheral wall 73 is located on the first direction D1 side of the end 60E of the center-side cam portion 60 on the first direction D1 side. Also, of the outer peripheral wall 73, all but a part of the protruding portion 75 are located on the second direction D2 side of the center-side pressing surface 69.

[0080] The length L7 from the center-side pressing surface 69 to the second-direction D2 end 67A of the center-side assist cam surface 60A is longer than the length L15 from the pressure-side pressing surface 98A to the first-direction end face 77B of the pressure-side fitting tooth 77. Therefore, when the clutch center 40 and the pressure plate 70 are assembled, the second-direction D2 end 67A of the center-side assist cam surface 60A is located on the first-direction D1 side of the pressure-side pressing surface 98A. Here, when the pressure-side assist cam surface 90A and the center-side assist cam surface 60A are in contact, the second-direction D2 end 67A of the center-side assist cam surface 60A, when viewed along the axis of the output shaft 15, coincides with the pressure-side cam hole 73H (see also Figure 14) and is located on the second-direction D2 side of the outer surface 98B of the pressure-side flange 98. Furthermore, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is positioned further to the second direction D2 than the end face 77A of the pressure-side fitting tooth 77 on the second direction D2 side. Also, in this case, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is positioned further to the second direction D2 than the outermost input-side rotating plate 20A and the outermost output-side rotating plate 22A. That is, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is positioned further to the second direction D2 than the rotating plate (output-side rotating plate 22 in Figure 1) that is located furthest to the second direction D2 among the multiple input-side rotating plates 20 and multiple output-side rotating plates 22.

[0081] Furthermore, the position of the pressure plate 70 and the clutch center 40 in direction D when the pressure-side slipper cam surface 90S (see Figure 17) and the center-side slipper cam surface 60S (see Figure 17) begin to make contact does not change from the position when the pressure-side assist cam surface 90A and the center-side assist cam surface 60A make contact. Figure 17 is a cross-sectional view of the clutch device 10 when the pressure-side slipper cam surface 90S and the center-side slipper cam surface 60S begin to make contact. As shown in Figure 17, when the pressure-side slipper cam surface 90S and the center-side slipper cam surface 60S begin to come into contact, and when the pressure plate 70 is moving in the second direction D2 due to the action of the pressure-side slipper cam surface 90S and the center-side slipper cam surface 60S, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is positioned further to the second direction D2 than the end face 77A of the pressure-side fitting tooth 77 on the second direction D2 side. Also, at this time, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is positioned further to the second direction D2 than the outermost input-side rotating plate 20A and the outermost output-side rotating plate 22A. In other words, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is located on the second direction D2 side of the multiple input-side rotating plates 20 and multiple output-side rotating plates 22 that is located furthest to the second direction D2 side (in Figure 17, the output-side rotating plate 22).

[0082] Figure 18 is a cross-sectional view of the clutch device 10 in a half-clutch state. When the clutch device 10 is in a "half-clutch state," the pressure plate 70 is located in a second direction D2 side than the state in which it is closest to the clutch center 40 and pressing against the input-side rotating plate 20 and the output-side rotating plate 22, and is located in a first direction D1 side than the state in which it is in contact with the stopper plate 100. As shown in Figure 18, in the half-clutch state, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is located in a second direction D2 side than the end face 77A of the pressure-side fitting teeth 77 on the second direction D2 side. Also, at this time, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is located in a second direction D2 side than the outermost input-side rotating plate 20A and the outermost output-side rotating plate 22A. In other words, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is located further towards the second direction D2 than the rotating plate (in Figure 18, the output-side rotating plate 22) among the multiple input-side rotating plates 20 and multiple output-side rotating plates 22.

[0083] The stopper plate 100 is provided so as to be in contact with the pressure plate 70. The stopper plate 100 is a member that prevents the pressure plate 70 from moving away from the clutch center 40 in a second direction D2 by a predetermined distance or more. The stopper plate 100 is fixed to the boss portion 54 of the clutch center 40 by bolts 28. A threaded portion 54a into which the bolts 28 are screwed is formed on the inside of the boss portion 54. The pressure plate 70 is attached to the clutch center 40 by tightening the stopper plate 100 to the boss portion 54 with bolts 28 while the clutch spring 25 is arranged in the spring housing portion 84. The stopper plate 100 is formed in a substantially triangular shape in plan view.

[0084] Figure 19 is a cross-sectional view of the clutch device 10 when the pressure plate 70 is in contact with the stopper plate 100. When the pressure plate 70 moves in the second direction, with the pressure-side slipper cam surface 90S and the center-side slipper cam surface 60S in contact, the pressure plate 70 comes into contact with the stopper plate 100. Even when the pressure plate 70 is in contact with the stopper plate 100, the pressure-side slipper cam surface 90S and the center-side slipper cam surface 60S remain in contact. In the state shown in Figure 19, the pressure plate 70 is furthest from the clutch center 40 in the second direction D2. When the pressure plate 70 is in contact with the stopper plate 100, the end face 74D of the annular wall 74A of the pressure plate 70 is located on the first direction D1 side of the end 58D of the center-side fitting portion 58 on the second direction D2 side. At this time, the end face 74D of the annular wall 74A of the pressure plate 70 is located on the second direction D2 side than the center side pressing surface 69 of the center side flange 68. Therefore, the cylindrical portion 74 is located on the second direction D2 side than the center side pressing surface 69. Also, at this time, the end 88E of the pressure side fitting portion 88 on the first direction D1 side is located on the first direction D1 side than the end 58D of the center side fitting portion 58 on the second direction D2 side.

[0085] Furthermore, when the pressure plate 70 is in contact with the stopper plate 100, a portion of the protrusion 75 is located on the first direction D1 side of the center-side pressing surface 69, and the other portion of the protrusion 75 is located on the second direction D2 side of the center-side pressing surface 69. At this time, the end face of the cylindrical portion 74 on the first direction D1 side (here, the end face 74D of the annular wall 74A and the end face 77B of the pressure-side fitting teeth 77) is located on the second direction D2 side of the center-side pressing surface 69. A portion of the protrusion 75 is positioned to overlap with a portion of the center-side recess 59 when viewed along the axis of the output shaft 15. The center-side recess 59 is located on the first direction D1 side of the center-side cam portion 60 and the center-side fitting portion 58 (see also Figure 7). A portion of the outer peripheral wall 73 is located on the first direction D1 side of the end 60E of the center-side cam portion 60 on the first direction D1 side. Even when the pressure plate 70 is located furthest to the first direction D1 side, a portion of the outer peripheral wall 73 and a portion of the pressure-side fitting teeth 77 are located furthest to the first direction D1 side of the end 60E of the center-side cam portion 60 on the first direction D1 side. Therefore, in all states from the state in which the pressure plate 70 is located furthest to the first direction D1 side to the state in which the pressure plate 70 is located furthest to the second direction D2 side, at least a portion of the outer peripheral wall 73 and at least a portion of the pressure-side fitting teeth 77 are located furthest to the first direction D1 side of the end 60E of the center-side cam portion 60 on the first direction D1 side.

[0086] Furthermore, when the pressure plate 70 is in contact with the stopper plate 100, the end face 74D of the annular wall 74A is located on the second direction D2 side of the center-side recess 59. The end face 74D of the annular wall 74A is located on the first direction D1 side of the center-side cam portion 60E on the first direction D1 side. At this time, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is located on the second direction D2 side of the pressure-side fitting tooth 77A on the second direction D2 side. Also, at this time, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is located on the second direction D2 side of the outermost input-side rotating plate 20A and the outermost output-side rotating plate 22A. In other words, the end 67A of the center-side assist cam surface 60A on the second direction D2 side is located on the second direction D2 side of the multiple input-side rotating plates 20 and multiple output-side rotating plates 22 that is located furthest to the second direction D2 side (the output-side rotating plate 22 in Figure 19).

[0087] Here, the assembly of the clutch center 40 and the pressure plate 70 will be described. The clutch center 40 and the pressure plate 70 are assembled, for example, to an engine installed in a motorcycle. The clutch housing 30 and the clutch center 40 are attached to an output shaft 15 that extends horizontally (direction D). The input side rotating plate 20 and the output side rotating plate 22 are attached to the clutch housing 30. The input side rotating plate 20 is attached to the clutch housing 30 by inserting a claw portion formed on its outer edge so as to protrude radially outward into a notch 30C in the clutch housing 30. The pressure plate 70 is assembled by moving toward the clutch center 40, as shown in Figures 20A and 20B. In Figure 20A, since the pressure plate 70 is not assembled to the clutch center 40, the output side rotating plate 22 is biased downward due to its own weight. The downward direction is an example of the first radial direction in the present invention. Figure 20C is a view of Figure 20A from the first direction D1. As shown in Figure 20C, the upper part of the output-side rotating plate 22 is spaced downward from the upper part of the clutch housing 30, and the lowest end 22D of the output-side rotating plate 22 is supported by the inner circumferential surface 33N of the lower part of the clutch housing 30. Figure 20C shows a straight line SL1 passing through the lowest end 22D of the output-side rotating plate 22 and the axis CL of the output shaft 15 (see Figure 1), and a straight line SL2 perpendicular to the straight line SL1 and passing through the axis CL. Among the rotating plate grooves 22c of the output-side rotating plate 22, the rotating plate groove 22cU that passes through the straight line SL1 and is located on the opposite side of the lowest end 22D (in this case, upward) relative to the straight line SL2 is located radially inward among the multiple rotating plate grooves 22c. Upward is an example of the second radial direction in the present invention. Here, the rotating plate groove 22cU is located at the uppermost position among the multiple rotating plate grooves 22C. At this time, the projection 75 is also located on the opposite side of the lowest end 22D with respect to the straight line SL2. When the rotational centers of the clutch housing 30 and the pressure plate 70 are located coaxially (i.e., on the axis CL), the edge 75E on the first direction D1 side of the inclined surface 75S1 (see Figure 20B) is located inward from the rotating plate groove 22cU.Thus, with the lowest end 22D of the output-side rotating plate 22 supported by the inner circumferential surface 33N of the lower part of the clutch housing 30, and with the rotational axes of the clutch housing 30 and the pressure plate 70 located coaxially (i.e., on the axis CL), the edge 75E of the inclined surface 75S1 on the first direction D1 side is located inward from the rotating plate groove 22cU located on the opposite side (in this case, upward) from the lowest end 22D with respect to the straight line SL2. Therefore, the pressure plate 70 can be easily assembled to the input-side rotating plate 20 and the output-side rotating plate 22 attached to the clutch housing 30. This is because, as shown in Figure 20A, when the input-side rotating plate 20 and the output-side rotating plate 22 are attached to the clutch housing 30, if the operator moves the pressure plate 70 toward the first direction D1, the projection 75 comes into contact with the inner peripheral edge 22N of the output-side rotating plate 22, as shown in Figure 20B, and the inclined surface 75S1 can push up the output-side rotating plate 22. By the operator moving the pressure plate 70 toward the first direction D1, all of the output-side rotating plates 22 are pushed up by the inclined surface 75S1, and the pressure-side fitting teeth 77 can be inserted into the inner diameter side of the input-side rotating plate 20 and the output-side rotating plate 22. This allows the clutch housing 30, clutch center 40, pressure plate 70, input-side rotating plate 20, and output-side rotating plate 22 to be attached to the engine.

[0088] As shown in Figure 2, when the rotational axes of the clutch housing 30, the output rotating plate 22, and the pressure plate 70 are located coaxially (i.e., on the axis CL (see Figure 1)), the radial distance L21 between the edge 75E (see also Figure 9) on the first direction D1 side of the inclined surface 75S1 and the inner peripheral edge 22N of the output rotating plate 22 is longer than the radial distance L20 between the inner peripheral surface 33N of the side wall 33 and the outer peripheral edge 22U of the output rotating plate 22. The output rotating plate 22 attached to the clutch housing 30 can move radially by up to a distance L20 (see also Figure 20B) due to its own weight, etc. Since the distance L21 is longer than the distance L20, even if the output rotating plate 22 moves radially, the edge 75E of the inclined surface 75S1 is located radially inward from the inner peripheral edge 22N of the output rotating plate 22. At this time, the input-side rotating plate 20 is held in the clutch housing 30 (see Figure 1). In this state, when the operator moves the pressure plate 70 toward the first direction D1, the projection 75 comes into contact with the inner peripheral edge 22N of the output-side rotating plate 22, as shown in Figure 20B, and the output-side rotating plate 22 is pushed up. By the operator moving the pressure plate 70 toward the first direction D1, all of the output-side rotating plates 22 are pushed up by the inclined surface 75S1, and the pressure-side fitting teeth 77 can be easily inserted into the inner diameter side of the input-side rotating plate 20 and the output-side rotating plate 22. This makes it easy and reliable to assemble the clutch housing 30, clutch center 40, pressure plate 70, input-side rotating plate 20, and output-side rotating plate 22. Making the gap L21 longer than the gap L20 is effective in facilitating assembly even when the clutch housing 30 is removed from the engine and the rotational axes of the clutch housing 30, the output-side rotating plate 22, and the pressure plate 70 are extended vertically.

[0089] Oil is supplied to the clutch device 10. The oil flows through the hollow portion 15H of the output shaft 15 shown in Figure 1 into the clutch center 40 and the pressure plate 70, and is then supplied to the input side rotating plate 20 and the output side rotating plate 22 through the gap between the center side fitting portion 58 and the pressure side fitting portion 88, and through the oil discharge hole 79 (see Figure 7). The oil absorbs heat and suppresses wear of the friction material. The clutch device 10 of this embodiment is a so-called wet multi-plate friction clutch device.

[0090] Next, the operation of the clutch device 10 in this embodiment will be described. As described above, the clutch device 10 is positioned between the engine and the transmission of the motorcycle, and the driver operates the clutch lever to transmit and interrupt the rotational driving force of the engine to the transmission.

[0091] In the clutch device 10, if the motorcycle operator does not operate the clutch lever, the clutch release mechanism (not shown) does not press the push rod 16A, so the pressure plate 70 presses the input side rotating plate 20 and the output side rotating plate 22 by the biasing force (elastic force) of the clutch spring 25. As a result, the clutch device 10 enters a state where the input side rotating plate 20 and the output side rotating plate 22 are pressed against each other by the clutch center 40 and the pressure plate 70, that is, the clutch is frictionally coupled and in the ON state. When the clutch is in the ON state, the rotational driving force of the engine is transmitted to the output shaft 15.

[0092] When the clutch is ON, the oil flowing through the hollow portion 15H of the output shaft 15 and flowing out from the tip portion 15T of the output shaft 15 falls or splashes into the cylindrical portion 80 and adheres to it (see arrow F in Figure 1). The oil adhering to the cylindrical portion 80 is guided into the pressure plate 70. As a result, the oil flows out to the outside of the pressure plate 70 through the oil discharge hole 79. The oil also flows out to the outside of the pressure plate 70 through the gap between the center-side fitting portion 58 and the pressure-side fitting portion 88. The oil that flows out to the outside of the pressure plate 70 is then supplied to the input-side rotating plate 20 and the output-side rotating plate 22.

[0093] On the other hand, when the clutch is ON and the motorcyclist operates the clutch lever, the clutch release mechanism (not shown) presses the push rod 16A, causing the pressure plate 70 to be displaced in a direction away from the clutch center 40 (second direction D2) against the biasing force of the clutch spring 25. As a result, the clutch center 40 enters the OFF state, where the frictional connection between the input side rotating plate 20 and the output side rotating plate 22 is released, causing the rotational drive of the output shaft 15 to be dampened or stopped. In other words, the transmission of the engine's rotational driving force to the output shaft 15 is interrupted.

[0094] In the clutch-off state, the oil flowing within the hollow portion 15H of the output shaft 15 and flowing out from the tip portion 15T of the output shaft 15 is guided into the pressure plate 70, similar to the clutch-on state. At this time, the pressure plate 70 is separated from the clutch center 40, so the amount of engagement with the center-side fitting portion 58 and the pressure-side fitting portion 88 is reduced. As a result, the oil in the cylindrical portion 80 flows more actively to the outside of the pressure plate 70 and flows to various parts inside the clutch device 10. In particular, oil can be actively guided between the input-side rotating plate 20 and the output-side rotating plate 22, which are separated from each other.

[0095] Furthermore, when the driver releases the clutch operating lever while the clutch is OFF, the pressure on the pressure plate 70 via the push member 16B by the clutch release mechanism (not shown) is released, and the pressure plate 70 is displaced in a direction (first direction D1) that approaches the clutch center 40 by the biasing force of the clutch spring 25.

[0096] As described above, according to the clutch device 10 of this embodiment, as shown in Figure 19, when the pressure plate 70 is in contact with the stopper plate 100, the end face 74D of the annular wall 74A of the pressure plate 70 is located on the first direction D1 side than the end 58D on the second direction D2 side of the center-side fitting portion 58. As a result, even when the pressure plate 70 is in contact with the stopper plate 100, the fitting between the pressure plate 70 and the clutch center 40 does not come undone. Here, the output-side rotating plate 22 is held by the pressure plate 70. Therefore, even when the pressure plate 70 is in contact with the stopper plate 100, the radial positional displacement of the input-side rotating plate 20 and the output-side rotating plate 22 is suppressed. As a result, the radial positioning of the input-side rotating plate 20 and the output-side rotating plate 22 can be easily performed. In the clutch device 10 of this embodiment, the state in which the pressure plate 70 is in contact with the stopper plate 100 is the state in which the pressure plate 70 is furthest away from the clutch center 40 in the second direction D2. Therefore, when the pressure plate 70 is furthest away from the clutch center 40 in the second direction D2, the radial positioning of the input side rotating plate 20 and the output side rotating plate 22 can be easily performed.

[0097] In the clutch device 10 of this embodiment, the annular wall 74A is fitted onto the center-side fitting portion 58. Therefore, the portion of the annular wall 74A that is fitted onto the center-side fitting portion 58 (in this case, the pressure-side fitting portion 88) and a part of the pressure-side fitting teeth 77 can be arranged to overlap radially. This makes the pressure plate 70 more compact.

[0098] However, due to aging and deterioration, the input-side rotating plate 20 and / or the output-side rotating plate 22 may wear down and become thinner. In this case, the amount by which the input-side rotating plate 20 and / or the output-side rotating plate 22 have become thinner increases the distance that the pressure plate 70 can travel in the first direction D1, and there is a possibility that the pressure plate 70 will come into contact with the clutch center 40. However, according to this embodiment, the end face 74D of the annular wall 74A of the pressure plate 70 and the end face 77B of the pressure-side fitting teeth 77 face the center-side recess 59 of the clutch center 40 in direction D. Since the center-side recess 59 is recessed in the first direction D1, there is a gap between the end face 74D of the annular wall 74A and the center-side recess 59. Therefore, since the end face 74D of the annular wall 74A is prevented from contacting the center-side recess 59, the pressure plate 70 is less likely to come into contact with the clutch center 40.

[0099] In the clutch device 10 of this embodiment, as shown in Figure 9, in the radial direction of the pressure plate 70, the radial length L14 of the center-side recess 59 is longer than the radial length L13 of the pressure-side fitting teeth 77 and the radial length L26 of the cylindrical portion 74. Therefore, when the pressure plate 70 moves radially, it is possible to suppress the pressure plate 70 from contacting the clutch center 40.

[0100] According to the clutch device 10 of this embodiment, as shown in Figure 19, when the pressure plate 70 is in contact with the stopper plate 100, the end face 74D of the annular wall 74A on the first direction D1 side and the end face 77B of the pressure-side fitting teeth 77 on the first direction D1 side are located on the second direction D2 side of the center-side pressing surface 69 of the center-side flange 68. The protrusion 75 extends from the pressure-side fitting teeth 77 in the first direction D1. Therefore, when the pressure plate 70 is in contact with the stopper plate 100, it is possible to suppress the pressure plate 70 from contacting the clutch center 40.

[0101] In the clutch device 10 of this embodiment, when the clutch center 40 and the pressure plate 70 are assembled, as shown in Figure 20B, the protrusion 75 pushes up the output side rotating plate 22, thereby attaching the output side rotating plate 22 to the pressure side fitting teeth 77. At least a portion of the protrusion 75 of the pressure plate 70, specifically the end face 75A on the first direction D1 side, is positioned to overlap with the center side recess 59 when viewed along the axis of the output shaft 15. Therefore, when the clutch center 40 and the pressure plate 70 are assembled, it is possible to prevent the protrusion 75 from coming into contact with the clutch center 40.

[0102] In the clutch device 10 of this embodiment, as shown in Figure 1, the output-side rotating plate 22 is held by the pressure plate 70. As shown in Figure 16, when the pressure-side assist cam surface 90A and the center-side assist cam surface 60A are in contact, at least a portion of the protrusion 75 is positioned inside the center-side cam hole 43H when viewed from direction D (when viewed in the axial direction of the output shaft 15). Therefore, when assembling the clutch center 40 and the pressure plate 70, contact between the protrusion 75 and the clutch center 40 is prevented.

[0103] In the clutch device 10 of this embodiment, as shown in Figure 7, the protrusion 75 is formed in a shape in which its length in the circumferential direction S decreases as it approaches the first direction D1. In this embodiment, the protrusion 75 has inclined surfaces 75S2 and 75S3. As shown in Figures 20A and 20B, when assembling the pressure plate 70 to the clutch center 40, the pressure plate 70 and the output side rotating plate 22 may be rotated relative to each other in the circumferential direction S. For example, when an operator rotates the pressure plate 70 in the circumferential direction S while moving the pressure plate 70 in the first direction D1 to assemble it to the clutch center 40. In such a case, the output side rotating plate 22 rotates relative to the pressure plate 70. At this time, the output side rotating plate 22 can rotate relative to the pressure plate 70 along the inclined surface 75S2 or the inclined surface 75S3. Therefore, the output side rotating plate 22 is prevented from getting caught on the protrusion 75 and becoming difficult to rotate in the circumferential direction S. This makes it easier to position the input-side rotating plate 20 and the output-side rotating plate 22 in the circumferential direction S.

[0104] In the clutch device 10 of this embodiment, as shown in Figure 9, the projection 75 is formed in a shape in which its radial length decreases as it approaches the first direction D1. In this embodiment, the projection 75 has an inclined surface 75S1. The inclined surface 75S1 extends radially inward as it approaches the first direction D1 and is inclined with respect to the axial direction. As shown in Figure 20B, when the pressure plate 70 is attached while the projection 75 pushes up the input side rotating plate 20 and the output side rotating plate 22, the output side rotating plate 22 can move radially inward to radially outward along the inclined surface 75S1. This makes it easy to insert the pressure side fitting teeth 77 into the rotating plate groove 22c of the output side rotating plate 22, and also makes it easy to position the input side rotating plate 20 and the output side rotating plate 22 radially.

[0105] In the clutch device 10 of this embodiment, as shown in Figure 2, the radial distance L21 between the edge 75E on the first direction D1 side of the inclined surface 75S1 of the protruding portion 75 and the inner peripheral edge 22N of the output side rotating plate 22 is longer than the radial distance L20 between the inner peripheral surface 33N of the side wall 33 (see Figure 1) and the outer peripheral edge 22U of the output side rotating plate 22. Therefore, as shown in Figure 20A, when the pressure plate 70 is not assembled to the clutch center 40 and the output side rotating plate 22 falls due to its own weight, the output side rotating plate 22 can fall by a maximum length L20 (see Figure 20B). Because the radial distance L21 between the edge 75E of the protrusion 75 and the inner peripheral edge 22N of the output-side rotating plate 22 is longer than L20, even when the output-side rotating plate 22 is in a fallen state, the edge 75E of the inclined surface 75S1 is positioned radially inward from the inner peripheral edge 22N of the output-side rotating plate 22. Therefore, when assembling the pressure plate 70 to the clutch center 40, the output-side rotating plate 22 can be pushed up by the protrusion 75 simply by moving the pressure plate 70 in direction D. Thus, the radial positioning of the output-side rotating plate 22 can be more favorably achieved.

[0106] In the clutch device 10 of this embodiment, as shown in Figure 20B, the radial distance L22 between the outer peripheral surface 77U of the pressure-side fitting teeth 77 and the inner peripheral edge 22N of the output-side rotating plate 22 is shorter than the radial distance L20 between the inner peripheral surface 33N of the side wall 33 (see Figure 1) shown in Figure 2 and the outer peripheral edge 22U of the output-side rotating plate 22. Therefore, as shown in Figure 20B, when the output-side rotating plate 22 is pushed up by the protrusion 75, contact between the output-side rotating plate 22 and the inner peripheral surface 33N of the side wall 33 is prevented. This allows the pressure plate 70 to be assembled to the clutch center 40 more smoothly.

[0107] In the clutch device 10 of this embodiment, as shown in Figure 20C, when the output-side rotating plate 22 is supported by the inner circumferential surface 33N, the edge 75E of the inclined surface 75S1 (see Figure 20B) is located inside the rotating plate groove 22cU, which is the innermost in the radial direction among the multiple rotating plate grooves 22c. Therefore, as shown in Figure 20B, when the pressure plate 70 is moved in direction D, the edge 75E of the inclined surface 75S1 is prevented from contacting the output-side rotating plate 22. This allows the pressure-side fitting teeth 77 to be easily inserted into the rotating plate groove 22c of the output-side rotating plate 22, and also facilitates the radial positioning of the output-side rotating plate 22. In this embodiment, direction D is substantially horizontal. However, even if direction D is vertical, for example, if the output-side rotating plate 22 is radially offset, the radial positioning of the output-side rotating plate 22 can be similarly facilitated.

[0108] When the pressure plate 70 is in contact with the stopper plate 100 (see Figure 19), for example, if the end face 74D of the annular wall 74A is located inside the center-side recess 59, the distance between the end face 74D of the annular wall 74A and the center-side recess 59 becomes relatively close when the pressure plate 70 is not in contact with the stopper plate 100. Therefore, as described above, when wear occurs on the input-side rotating plate 20 and / or the output-side rotating plate 22, the pressure plate 70 may come into contact with the clutch center 40. However, in this embodiment, when the pressure plate 70 is in contact with the stopper plate 100, the end face 74D of the annular wall 74A is located on the second direction D2 side of the center-side recess 59. Therefore, the structure is such that it is relatively unlikely to come into contact with the clutch center 40.

[0109] In the clutch device 10 of this embodiment, as shown in Figure 19, when the pressure plate 70 is in contact with the stopper plate 100, the end face 74D of the annular wall 74A is positioned on the first direction D1 side of the end 60E of the center-side cam portion 60 on the first direction D1 side. That is, a part of the cylindrical portion 74 is positioned on the first direction D1 side of the center-side cam portion 60. As a result, when the pressure plate 70 is in contact with the stopper plate 100, the input-side rotating plate 20 and the output-side rotating plate 22 are prevented from falling and, for example, becoming caught and held by the center-side cam portion 60. Therefore, even when the pressure plate 70 is in contact with the stopper plate 100 during assembly of the clutch device 10, the radial positional displacement of the input-side rotating plate 20 and the output-side rotating plate 22 is prevented.

[0110] In the clutch device 10 of this embodiment, as shown in Figure 9, the end 58E of the center-side fitting portion 58 on the first direction D1 side is located on the first direction D1 side of the center-side pressing surface 69 of the center-side flange 68. The input-side rotating plate 20 and the output-side rotating plate 22 are pressed against the center-side pressing surface 69. If the end 58E of the center-side fitting portion 58 on the first direction D1 side is located on the second direction D2 side of the center-side pressing surface 69, it would be necessary to extend the center-side fitting portion 58 on the second direction D2 side in order to set the axial length of the center-side fitting portion 58 to a predetermined value. However, according to this embodiment, the extension of the center-side fitting portion 58 on the second direction D2 side is suppressed. Therefore, the clutch center 40 can be made more compact and lighter.

[0111] In the clutch device 10 of this embodiment, the pressure-side fitting portion 88 is the portion of the annular wall 74A that extends from the end in the first direction D1 to the second direction D2. The pressure-side fitting portion 88 is slidably fitted with the center-side fitting portion 58 in direction D. Therefore, the center-side fitting portion 58 of the clutch center 40 fits with the pressure plate 70 at the end of the annular wall 74A of the pressure plate 70 on the first direction D1 side. In this embodiment, the extension of the center-side fitting portion 58 to the second direction D2 is suppressed. Therefore, the clutch center 40 can be made more compact and lighter.

[0112] In the clutch device 10 of this embodiment, the pressure-side fitting portion 88 is located on the first direction D1 side of the end 25A of the clutch spring 25. In this embodiment, the entirety of the pressure-side fitting portion 88 is located on the first direction D1 side of the end 25A of the clutch spring 25. Therefore, there is no need to extend the center-side fitting portion 58 on the second direction D2 side. The length of the clutch center 40 in direction D is suppressed. Consequently, the clutch center 40 can be made more compact and lighter.

[0113] In the clutch device 10 of this embodiment, the pressure-side fitting portion 88 is the portion of the annular wall 74A that extends from the end in the first direction D1 to the second direction D2. The pressure-side fitting portion 88 is slidably fitted with the center-side fitting portion 58 in direction D. As shown in Figure 19, when the pressure plate 70 is at its furthest distance from the clutch center 40, the end 88E of the pressure-side fitting portion 88 in the first direction D1 is located on the first direction D1 side of the center-side fitting portion 58, rather than the end 58D of the center-side fitting portion 58 in the second direction D2. Therefore, even when the pressure plate 70 is at its furthest distance from the clutch center 40, the pressure-side fitting portion 88 is fitted with at least a part of the center-side fitting portion 58, and the pressure plate 70 does not come off the clutch center 40. This suppresses misalignment of the radial positions of the input-side rotating plate 20 and the output-side rotating plate 22, and also allows for accurate radial positioning of the pressure plate 70 relative to the clutch center 40, even when the pressure plate 70 is at its furthest distance from the clutch center 40.

[0114] In the clutch device 10 of this embodiment, as shown in Figure 1, when the pressure-side assist cam surface 90A and the center-side assist cam surface 60A are in contact, the end face 75A of the projection 75 extending from the pressure-side fitting teeth 77 on the first direction D1 side is located on the first direction D1 side than the center-side pressing surface 69. A part of the projection 75 is located on the first direction D1 side than the center-side pressing surface 69, and the other part of the projection 75 is located on the second direction D2 side than the center-side pressing surface 69. Here, the output-side rotating plate 22 is held by the outer peripheral wall 73 of the pressure plate 70 (in this case, the pressure-side fitting teeth 77). Therefore, if the protrusion 75 is located on the second direction D2 side of the center-side pressing surface 69 (i.e., the outer peripheral wall 73 is located on the second direction D2 side of the center-side pressing surface 69), the output-side rotating plate 22 may detach from the outer peripheral wall 73 of the pressure plate 70, potentially causing a misalignment of the output-side rotating plate 22 in the axial direction. However, according to this embodiment, when the pressure-side assist cam surface 90A and the center-side assist cam surface 60A are in contact, the detachment of the output-side rotating plate 22 from the pressure plate 70 is suppressed. Therefore, when assembling the pressure plate 70, the positioning of the input-side rotating plate 20 and the output-side rotating plate 22 can be easily facilitated. Furthermore, in this embodiment, as shown in Figure 19, even when the pressure plate 70 is in contact with the stopper plate 100, the end face 75A of the protrusion 75 on the first direction D1 side is located on the first direction D1 side of the center-side pressing surface 69. Even when the pressure plate 70 is separated from the clutch center 40 and in contact with the stopper plate 100, the output side rotating plate 22 is prevented from coming off the pressure plate 70.

[0115] In the clutch device 10 of this embodiment, as shown in Figure 10, multiple (in this case, three) protrusions 75 are provided in the circumferential direction. The total length 3 × W1, which is the sum of the lengths S in the circumferential direction of the protrusions 75, is shorter than the half-circumferential length W2 of the cylindrical portion 74. In this embodiment, since the overall volume of the protrusions 75 is relatively small, the pressure plate 70 can be made lighter.

[0116] In the clutch device 10 of this embodiment, in all states from the state in which the pressure plate 70 is positioned furthest toward the first direction D1 (see Figure 1) to the state in which the pressure plate 70 is positioned furthest toward the second direction D2 (see Figure 19), a part of the outer peripheral wall 73 (here, the end face 75A of the protruding portion 75 in the first direction) is located toward the first direction D1 than the center-side pressing surface 69, and the other part of the outer peripheral wall 73 is located toward the first direction D1 than the end 60E of the center-side cam portion 60 in the first direction D1. Therefore, in all states when the pressure plate 70 moves in direction D, a part of the outer peripheral wall 73 is always located toward the first direction D1 than the center-side pressing surface 69. As a result, when the pressure plate 70 moves in direction D, the output-side rotating plate 22 is prevented from disengaging from the outer peripheral wall 73 of the pressure plate 70 (here, the pressure-side fitting teeth 77). Therefore, even if the pressure plate 70 moves in direction D during the assembly of the clutch device 10, the positioning of the input-side rotating plate 20 and the output-side rotating plate 22 can be easily performed.

[0117] Figure 21 is a perspective view showing a modified pressure plate 370. As shown in Figure 21, the pressure plate 370 has three oil discharge holes 79L, 79M, and 79N1. Similar to the pressure plate 70 (see Figure 7), the oil discharge holes 79L, 79M, and 79N1 are each formed in one of the three aligned toothed portions 76. The oil discharge holes 79L, 79M, and 79N1 are arranged at approximately equal intervals in the circumferential direction S. The oil discharge holes 79L, 79M, and 79N1 are arranged at offset positions from each other in direction D.

[0118] In the modified pressure plate 370, a through hole 389 is formed in the pressure-side main body portion 72 instead of the through hole 89 (see Figure 8). The through hole 389 is formed in a substantially rectangular shape when viewed from direction D (see also Figure 22). A notch 387 is formed in the toothless portion 76 of the pressure plate 370. The notch 387 is a hole for discharging oil blocked by the pressure-side assist cam surface 90A to the outside of the pressure plate 70. As shown in Figure 22, the notch 387 is formed so as to be recessed from the end face 72D on the second direction D2 side of the pressure-side main body portion 72 toward the first direction D1. The notch 387 and the through hole 389 are in communication. The length of the notch 387 in the circumferential direction S is substantially the same as the length of the through hole 389 in the circumferential direction S. As shown in Figure 21, three notches 387 are formed along the circumferential direction S. The three notches 387 will also be referred to as notches 387L, 387M, and 387N. However, the name notch 387 will be used appropriately when it is common to all three notches 387L, 387M, and 387N. Notch 387L is formed in the toothed portion 76 in which the oil discharge hole 79L is formed, among the three toothed portions 76. Similarly, notches 387M and 387N are formed in the toothed portions 76 in which the oil discharge holes 79M and 79N1 are formed, among the three toothed portions 76. Notch 387 is located on the second direction D2 side of the oil discharge hole 79. As shown in Figure 23, the edge 387A of notch 387 on the first direction D1 side is located on the first direction D1 side of the end 95 of the pressure-side assist cam surface 90A on the second direction D2 side. The notch 387 is located close to the pressure-side assist cam surface 90A on the first circumferential direction S1 (rotational direction of the pressure plate 370) side. For example, as shown in Figure 21, the distance in the circumferential direction S between the pressure-side assist cam surface 90A, which is located on the second circumferential direction S2 side of the notch 387L, and the notch 387L is shorter than the distance in the circumferential direction S between the pressure-side slipper cam surface 90S, which is located on the first circumferential direction S1 side of the notch 387L, and the notch 387L. The same applies to the distances between the notches 387M and 387N and the pressure-side assist cam surface 90A.

[0119] As shown in Figure 23, the circumferential distance S between the notch 387 and the pressure-side assist cam surface 90A is approximately the same as the circumferential distance S between the oil discharge hole 79 and the pressure-side assist cam surface 90A. Here, the pressure-side assist cam surface 90A extends toward the first circumferential direction S1 as it moves toward the first direction D1, and is inclined with respect to the axial direction. For this reason, for example, the notch 387N is shifted toward the second circumferential direction S2, in the direction toward the oil discharge hole 79N1 where the pressure-side assist cam surface 90A is inclined. In this case, the distance between the notch 387N and the pressure-side assist cam surface 90A is approximately the same as the distance between the oil discharge hole 79N1 and the pressure-side assist cam surface 90A. The same applies to the oil discharge hole 79L and notch 387L shown in Figure 21, and the oil discharge hole 79L and notch 387M. In addition, with respect to the circumferential direction S, the oil discharge hole 79 and the notch 387 may be provided at the same position.

[0120] Here, for example, when the engine speed increases and the pressure plate 370 rotates in the first circumferential direction S1, oil flows out from the output shaft 15 (see Figure 1) into the pressure plate 370. At this time, the oil flows in the opposite direction to the rotation direction S1, i.e., in the rotation direction S2, and a portion of the oil is blocked by the pressure-side assist cam surface 90A. The oil blocked by the pressure-side assist cam surface 90A flows along the pressure-side assist cam surface 90A in the second direction D2. According to the above embodiment, the oil blocked by the pressure-side assist cam surface 90A is discharged to the outside of the pressure plate 70 through the notch 387. Furthermore, according to the above embodiment, as shown in Figure 23, since the edge 387A of the notch 387 is located on the first direction D1 side than the end 95 of the pressure-side assist cam surface 90A, the oil blocked by the pressure-side assist cam surface 90A can be discharged to the outside of the pressure plate 70 more reliably. Moreover, since the circumferential distance S between the oil discharge hole 79 and the pressure-side assist cam surface 90A and the circumferential distance S between the notch 387 and the pressure-side assist cam surface 90A are substantially the same, the oil blocked by the pressure-side assist cam surface 90A can be reliably discharged to the outside of the pressure plate 70 by the oil discharge hole 79 and the notch 387.

[0121] The number of notches 387 is not particularly limited. For example, two or more notches 387 may be formed in one toothed portion 76 (see Figure 21). Also, the shape of the notches 387 is not limited to the above-described modifications. In the modified example, the notches 387 were located on the second direction D2 side of the oil discharge hole 79, but for example, the notches 387 may extend to the first direction D1 side of the oil discharge hole 79.

[0122] <Second Embodiment> Figure 24 is a perspective view of the clutch center 140 according to the second embodiment. The clutch center 140 is housed in the clutch housing 30 (see Figure 1). The clutch center 140 is arranged concentrically with the clutch housing 30. As shown in Figure 24, the clutch center 140 has a center-side main body portion 142, a center-side recess 59, and a center-side flange 68. The center-side main body portion 142 includes an annular boss portion 143, an output shaft holding portion 50 provided in the center of the boss portion 143, a plurality of center-side cam portions 160 connected to the boss portion 143, and a housing portion recess 145. Three center-side cam portions 160 are arranged at equal intervals in the circumferential direction of the clutch center 140.

[0123] The center cam portion 160 is located radially outward from the output shaft holding portion 50. The center cam portion 160 has a center assist cam surface 160A and a center slipper cam surface 160S. A boss portion 54 is erected on the center cam portion 160.

[0124] The center cam portion 160 is provided with a protrusion 164. The protrusion 164 is formed on the radially inner portion of the center cam portion 160. The protrusion 164 is formed on the first circumferential direction S1 side and the second circumferential direction S2 side of the center cam portion 160, respectively. The protrusion 164 formed on the first circumferential direction S1 side will also be referred to as the first protrusion 164A, and the protrusion 164 formed on the second circumferential direction S2 side will also be referred to as the second protrusion 164B. The first protrusion 164A extends to the first circumferential direction S1 side. In the circumferential direction S, the first protrusion 164A extends to approximately the same position as the position on the center slipper cam surface 160S closest to the first circumferential direction S1. The second protrusion 164B, provided on the second circumferential direction S2 side, extends to the second circumferential direction S2 side. The second protrusion 164B extends in the circumferential direction S to approximately the same position as the second circumferential direction S2 side position of the center-side assist cam surface 160A. By providing the protrusion 164 on the center-side cam portion 160, the durability of the center-side cam portion 160 can be improved when the center-side assist cam surface 160A and the pressure-side assist cam surface 190A (see Figure 26), which will be described later, are in contact with each other and act together.

[0125] A stepped portion 165 is formed between the main inner surface 163A, which is the inner surface of the center cam portion 160, and the boss portion 143. The stepped portion 165 extends in the circumferential direction S. The stepped portion 165 is formed from the first end of the first convex portion 164A on the first circumferential direction S1 side to the second end of the second convex portion 164B on the second circumferential direction S2 side.

[0126] The housing recess 145 is formed between adjacent center-side cam portions 160 with respect to the circumferential direction S. The housing recess 145 is the portion into which the spring housing portion 184 (see Figure 26) of the pressure plate 170 (see Figure 26), which will be described later, is inserted. The housing recess 145 has a wall surface 146 and a bottom surface 147. The housing recess 145 may penetrate in direction D. The wall surface 146 is connected to the second protrusion 164B of one center-side cam portion 160L, the first protrusion 164A of the other center-side cam portion 160M, and the boss portion 143. The wall surface 146 is formed in a substantially C shape in plan view. The bottom surface 147 is the surface connected to the first direction D1 side of the wall surface 146. The wall surface 146 is located on the first direction D1 side of the end 158D of the center-side fitting portion 158 on the second direction D2 side. Parts of the wall surface 146 and the bottom surface 147 on the first circumferential direction S1 side are connected to the center-side cam hole 143H. When the spring housing portion 184 is inserted into the housing portion recess 145, there may be a gap between the wall surface 146 and the wall surface 185 of the spring housing portion 184 (described later), or there may be no gap (i.e., the wall surface 146 and the wall surface 185 may be fitted together).

[0127] As shown in Figure 25, a cam-side recess 166 is formed on the end face 160D of the center-side cam portion 160 on the first direction D1 side. The cam-side recess 166 is formed to recess toward the second direction D2 side. The cam-side recess 166 is formed on the center-side cam portion 160 toward the first circumferential direction S1 side than the boss portion 54. The cam-side recess 166 is formed in a substantially fan shape in plan view. The cam-side recess 166 is connected to the boss portion 143 on the radially inward side. The cam-side recess 166 is connected to the center-side cam hole 143H on the first circumferential direction S1 side. The formation of the cam-side recess 166 makes it possible to reduce the weight of the clutch center 140.

[0128] As shown in Figures 24 and 25, the clutch center 140 has a center-side cam hole 143H that penetrates a portion of the center-side main body portion 142. The center-side cam hole 143H extends from the boss portion 143 to the radially outward side of the center-side fitting portion 158. The center-side cam hole 143H is formed adjacent to the center-side assist cam surface 160A on the second circumferential direction S2 side. Viewed from direction D, a portion of the center-side assist cam surface 160A is located inside the center-side cam hole 143H.

[0129] Figure 26 is a perspective view of a pressure plate 170 according to a second embodiment. The pressure plate 170 is provided so as to be able to approach and move away from the clutch center 140 and to be able to rotate relative to it. The pressure plate 170 shown in Figure 26 is configured to be able to press the input side rotating plate 20 (see Figure 1) and the output side rotating plate 22 (see Figure 1). The pressure plate 170 is arranged concentrically with the clutch center 140 (see Figure 25) and the clutch housing 30 (see Figure 1). As shown in Figure 26, the pressure plate 170 comprises a pressure side body portion 172 and a pressure side flange 98. The pressure side body portion 172 protrudes from the pressure side flange 98 in a first direction D1. The pressure plate 70 holds a plurality of output side rotating plates 22 that are arranged alternately with the input side rotating plate 20.

[0130] The pressure-side main body portion 172 comprises a cylindrical portion 80, an outer peripheral wall 173, a plurality of pressure-side cam portions 190, a pressure-side fitting portion 88, and a spring housing portion 184.

[0131] The outer peripheral wall 173 is positioned radially outward from the cylindrical portion 80. The outer peripheral wall 173 extends in a first direction D1. The outer peripheral wall 173 has an annular wall 174A and a spline fitting portion 174B provided radially outward from the annular wall 174A. The spline fitting portion 174B has a plurality of pressure-side fitting teeth 177 extending in direction D and a plurality of spline grooves 178 formed between adjacent pressure-side fitting teeth 177. The pressure-side fitting teeth 177 hold the output-side rotating plate 22. The plurality of pressure-side fitting teeth 177 are aligned in the circumferential direction S. The plurality of pressure-side fitting teeth 177 are formed in the same shape. The pressure-side fitting teeth 77 protrude radially outward from the annular wall 174A.

[0132] The pressure-side cam portion 190 shown in Figure 26 is formed in a trapezoidal shape having cam surfaces 190A and 190S which are inclined surfaces. The pressure-side cam portion 190 is formed to protrude in the first direction D1 from the pressure-side flange 98. The pressure-side cam portions 190 are arranged at equal intervals in the circumferential direction S of the pressure plate 170. In this embodiment, the pressure plate 170 has three pressure-side cam portions 190, but the number of pressure-side cam portions 90 is not limited to three.

[0133] The pressure-side cam portion 190 is located radially outward from the cylindrical portion 80. The pressure-side cam portion 190 includes a pressure-side assist cam portion 191 including a pressure-side assist cam surface 190A, a pressure-side slipper cam portion 192 including a pressure-side slipper cam surface 190S, and a pressure-side cam body portion 193 located between the pressure-side assist cam portion 191 and the pressure-side slipper cam portion 192. The pressure-side assist cam portion 191, the pressure-side cam body portion 193, and the pressure-side slipper cam portion 192 are integrally formed.

[0134] As shown in Figure 27, the pressure-side cam portion 190 is connected to the pressure-side cam hole 173H, which will be described later, at its end on the second circumferential direction S2 side. As shown in Figure 26, the pressure-side cam portion 190 and the pressure-side cam hole 173H are connected on the second direction D2 side of the pressure-side slipper cam surface 190S.

[0135] The pressure plate 170 has a pressure-side cam hole 173H that penetrates a portion of the pressure-side main body portion 172 in direction D. The pressure-side cam hole 173H is located radially outward from the cylindrical portion 80. The pressure-side cam hole 173H is formed between the pressure-side assist cam surface 190A and the pressure-side slipper cam surface 190S of the adjacent pressure-side cam portion 190. As shown in Figure 27, when viewed from direction D, a portion of the pressure-side assist cam surface 190A is located inside the pressure-side cam hole 173H.

[0136] The pressure-side cam hole 173H has a cam hole recess 174. The cam hole recess 174 is formed on the first circumferential direction S1 side of the pressure-side cam hole 173H. The cam hole recess 174 is a recessed portion of the pressure-side cam hole 173H on the first circumferential direction S1 side. The cam hole recess 174 is connected to the pressure-side cam portion 190. The radial length of the cam hole recess 174 is formed to be approximately the same as the radial length of the pressure-side cam portion 190. When the pressure plate 170 and the clutch center 140 are assembled, the boss portion 54 (see Figure 24) is inserted into the area inside the cam hole recess 174. Therefore, the cam hole recess 174 prevents the boss portion 54 from interfering with the pressure plate 170.

[0137] As shown in Figure 27, the spring housing portion 184 is formed on the end face 190D of the pressure-side cam portion 190 on the second direction D2 side. The spring housing portion 184 is formed to be recessed from the end face 190D of the pressure-side cam portion 190 toward the first direction D1 side. When viewed from direction D, the spring housing portion 184 is formed in a substantially circular shape. The spring housing portion 184 is the part that houses the clutch spring 25 (see Figure 1).

[0138] As shown in Figure 26, the spring housing portion 184 has a wall surface 185 and a bottom surface 186. The wall surface 185 is a wall surface that surrounds the clutch spring 25 (see Figure 1) in the circumferential direction. The wall surface 185 extends from the end surface 190E on the first direction D1 side of the pressure-side cam portion 190 to the first direction D1. The wall surface 185 is also connected to the cylindrical portion 80 on the radially inner side. The bottom surface 186 is connected to the end of the wall surface 185 on the first direction D1 side. The bottom surface 186 is formed in a circular shape in plan view. When the pressure plate 170 is assembled to the clutch center 140 (see Figure 24), the portion of the spring housing portion 184 that is on the first direction D1 side of the pressure-side cam portion 190 is inserted into the housing recess 145 (see Figure 24) of the clutch center 140. Furthermore, at this time, the bottom surface 186 of the spring housing portion 184 is positioned to face the bottom surface 147 (see Figure 24) of the housing portion recess 145. By inserting the spring housing portion 184 into the housing portion recess 145 of the clutch center 140, the dimensions of the clutch device 10 in direction D can be made more compact.

[0139] <Third Embodiment> Figure 28 is a cross-sectional view of a clutch device 210 according to the third embodiment. As shown in Figure 28, the clutch device 210 includes an output shaft 15, an input side rotating plate 20, an output side rotating plate 22, a clutch housing 30, a clutch center 240, a pressure plate 270, a clutch spring 25, and a lifter plate 300. The clutch device 210 is a so-called external-cutting type clutch device in which the pressure plate 270 is located between the clutch center 240 and the clutch housing 230.

[0140] As shown in Figure 28, the clutch housing 30 supports the input side rotating plate 20. The pressure plate 270 supports all of the output side rotating plates 22. When the rotational axes of the clutch housing 30 and the output side rotating plates 22 are located coaxially (i.e., on axis CL), as shown in Figure 29, the radial distance between the inner circumferential surface 33N of the side wall 33 of the clutch housing 30 and the outer circumferential edge 22U of the output side rotating plate 22 is length L23. As shown in Figure 28, the clutch spring 25 is in contact with the clutch center 240. The clutch center 240 has a spring housing portion formed to be recessed from a first direction D1 to a second direction D2, for example. The clutch spring 25 is housed in this spring housing portion.

[0141] The lifter plate 300 is a component for displacing the pressure plate 270 in direction D. The lifter plate 300 is fixed to the pressure plate 270. The lifter plate 300 is fixed to a boss portion 254 formed on the pressure plate 270 by bolts 28. The lifter plate 300 rotates integrally with the pressure plate 270. The lifter plate 300 moves in direction D relative to the clutch center 240 and rotates relative to the clutch center 240. The lifter plate 300 is formed in a disc shape. Although not shown in the figures, the lifter plate 300 is provided with, for example, a release bearing. The release bearing is a component that is pressed by the release fork of a clutch release mechanism (not shown). Here, the clutch release mechanism is a mechanical device in a vehicle such as a motorcycle equipped with a clutch device 210 that presses the release bearing toward the output shaft 15 side (i.e., the second direction D2 side) via a release fork when the driver operates the clutch operation lever (not shown). The lifter plate 300 supports the clutch spring 25. The lifter plate 300 has insertion holes 304H into which bolts 28 that fix the lifter plate 300 to the pressure plate 270 are inserted.

[0142] The pressure plate 270 is provided by the lifter plate 300 so as to be able to move toward and away from the clutch center 240 and to rotate relative to it. The pressure plate 270 has a pressure-side body portion 72, similar to the pressure plate 70 (see Figure 7) according to the first embodiment. The pressure-side body portion 72 has a projection 75 and pressure-side fitting teeth 77, similar to the first embodiment. The projection 75 is formed in a shape in which its radial length decreases as it moves toward the first direction D1. An inclined surface 75S1 is formed on the outer circumferential surface of the projection 75, extending radially inward toward the end face 75A of the projection 75 on the first direction D1 side. As shown in Figure 29, when the rotational axes of the clutch housing 30, the output rotating plate 22, and the pressure plate 270 are located coaxially (i.e., on axis CL (see Figure 28)), the radial distance between the edge 75E on the first direction D1 side of the inclined surface 75S1 and the inner peripheral edge 22N of the output rotating plate 22 is length L24. Length L24 is longer than the radial distance L23 between the inner peripheral surface 33N of the side wall 33 and the outer peripheral edge 22U of the output rotating plate 22. The radial distance between the outer peripheral surface 77U of the pressure-side fitting teeth 77 and the inner peripheral edge 22N of the output rotating plate 22 is length L25. Length L25 is shorter than length L23. In the clutch device 210 according to the third embodiment, as with the clutch device 10 according to the first embodiment (see Figure 1), when the pressure plate 270 is not assembled to the clutch center 240, the output-side rotating plate 22 falls due to its own weight and is supported by the inner circumferential surface 33N of the clutch housing 30. When the output-side rotating plate 22 is supported by the inner circumferential surface 33N, the edge 75E of the inclined surface 75S1 can be located radially inward from the inner circumferential edge 22N of the output-side rotating plate 22. Therefore, in the clutch device 210 according to the third embodiment, as with the clutch device 10 according to the first embodiment (see Figure 1), the radial positioning of the output-side rotating plate 22 can be suitably achieved. Furthermore, when the output-side rotating plate 22 is pushed up by the protrusion 75, contact between the output-side rotating plate 22 and the inner circumferential surface 33N of the side wall 33 is prevented.Therefore, in the clutch device 210 according to the third embodiment, similar to the clutch device 10 according to the first embodiment, the pressure-side fitting teeth 77 can be easily inserted into the inner diameter side of the input-side rotating plate 20 and the output-side rotating plate 22. This allows the pressure plate 270 to be assembled to the clutch center 240 more smoothly.

[0143] Preferred embodiments of the present invention have been described above. However, the embodiments described above are merely illustrative, and the present invention can be implemented in various other forms.

[0144] In the embodiments described above, only the pressure plate held the output-side rotating plate 22, but this is not limited to this. The clutch center may also hold a portion of the output-side rotating plate 22.

[0145] In the embodiments described above, the clutch center had a center-side cam portion and the pressure plate had a pressure-side cam portion, but the invention is not limited to these. The present invention can also be applied to clutch devices that do not have a center-side cam portion or a pressure-side cam portion.

[0146] 10 Clutch device 15 Output shaft 20 Input side rotating plate 22 Output side rotating plate 25 Clutch spring 30 Housing 40 Clutch center 43H Center side cam hole 50 Output shaft holding part 58 Center side fitting part 60 Center side cam part 60A Center side assist cam surface 60S Center side slipper cam surface 70 Pressure plate 73 Outer peripheral wall 74 Cylindrical part 74D End face 84 Spring housing part 88 Pressure side fitting part 90 Pressure side cam part 90A Pressure side assist cam surface 90S Pressure side slipper cam surface 100 Stopper plate D1 First direction D2 Second direction

Claims

1. A clutch device for transmitting or interrupting the rotational driving force of an input shaft to an output shaft, comprising: a clutch center housed in a clutch housing that rotates upon receiving the rotational driving force and holds a plurality of input-side rotating plates arranged in an axial direction which is the direction of the axis of the output shaft, and which rotates together with the output shaft; a plurality of output-side rotating plates arranged alternately with the input-side rotating plates in the axial direction; a pressure plate that is movable toward and toward the clutch center in the axial direction, holds the output-side rotating plates, and presses the input-side rotating plates and the output-side rotating plates; and a clutch spring that biases the pressure plate in the first direction, when the direction in which the pressure plate approaches the clutch center along the axial direction is defined as the first direction, and the direction in which the pressure plate moves toward the clutch center along the axial direction is defined as the second direction. A clutch device comprising: a stopper plate fixed to the clutch center and in contact with the pressure plate, thereby restricting the pressure plate from moving away from the clutch center by a predetermined distance or more in the second direction; the clutch center having an output shaft holding portion through which the output shaft is inserted; and a center-side fitting portion located radially outward from the output shaft holding portion and into which the pressure plate is slidably fitted in the axial direction; the pressure plate having a cylindrical portion having an annular wall formed in a cylindrical shape extending in the first direction and pressure-side fitting teeth protruding radially from the annular wall and holding the output-side rotating plate; and the end of the annular wall in the first direction being located on the first direction side of the center-side fitting portion in the second direction when the pressure plate is in contact with the stopper plate.

2. The clutch device according to claim 1, wherein the annular wall of the pressure plate is fitted onto the center-side fitting portion.

3. The clutch device according to claim 1, wherein the clutch center comprises a center-side pressing surface that sandwiches the input-side rotating plate and the output-side rotating plate between itself and the pressure plate, and a center-side recess formed on the radially inward side of the center-side pressing surface and recessed or penetrating in the first direction relative to the center-side pressing surface, and at least a portion of the end face on the first direction side of the cylindrical portion faces the center-side recess in the axial direction.

4. The clutch device according to claim 3, wherein at least a portion of the end face on the first direction side of the pressure-side mating tooth faces the center-side recess in the axial direction.

5. The clutch device according to claim 3, wherein the radial length of the center recess is longer than the radial length of the pressure-side mating teeth.

6. The clutch device according to claim 3, wherein the pressure plate has a plurality of pressure-side cam portions having a pressure-side assist cam surface, the clutch center is located radially outward from the output shaft holding portion and has a plurality of center-side cam portions having a center-side assist cam surface facing the pressure-side assist cam surface in the circumferential direction of the output shaft, the pressure-side assist cam surface and the center-side assist cam surface are configured to increase the pressing force between the input-side rotating plate and the output-side rotating plate by generating a force in a direction that brings the pressure plate closer to the clutch center when the pressure plate rotates relative to the clutch center, and when the pressure plate is in contact with the stopper plate, the end of the annular wall in the first direction is located on the second direction side of the center-side pressing surface.

7. The clutch device according to claim 6, wherein the pressure plate has a projection extending from the cylindrical portion in the first direction beyond the end of the cylindrical portion in the first direction, and when the pressure plate is in contact with the stopper plate, the end of the cylindrical portion in the first direction is located on the second direction side of the center-side pressing surface.

8. The clutch device according to claim 7, wherein the projection extends from the pressure-side fitting tooth in a first direction beyond the first end of the pressure-side fitting tooth in the first direction, and when the pressure plate is in contact with the stopper plate, the first end of the pressure-side fitting tooth is located on the second direction side of the center-side pressing surface.

9. The clutch device according to claim 3, wherein the pressure plate has a projection extending from the cylindrical portion beyond the end of the cylindrical portion in the first direction, and at least a portion of the projection is configured to overlap the center-side recess when viewed along the axis.

10. The clutch device according to claim 9, wherein when the pressure plate is in its closest position to the clutch center, at least a portion of the protrusion is configured to overlap with the center-side recess when viewed along the axis.

11. The clutch device according to claim 9, wherein the pressure plate has a plurality of pressure-side cam portions having a pressure-side assist cam surface, the clutch center has a plurality of center-side cam portions having a center-side assist cam surface facing the pressure-side assist cam surface, the pressure-side assist cam surface and the center-side assist cam surface are configured to increase the pressing force between the input-side rotating plate and the output-side rotating plate by generating a force in a direction that brings the pressure plate closer to the clutch center when the pressure plate rotates relative to the clutch center, and when the pressure-side assist cam surface and the center-side assist cam surface are in contact, at least a part of the protruding portion is configured to overlap with the center-side recess when viewed along the axis.

12. The clutch device according to claim 9, wherein the pressure plate has a plurality of pressure-side cam portions having pressure-side slipper cam surfaces, the clutch center has a plurality of center-side cam portions having center-side slipper cam surfaces facing the pressure-side slipper cam surfaces, the pressure-side slipper cam surfaces and the center-side slipper cam surfaces are configured to reduce the pressing force between the input-side rotating plate and the output-side rotating plate when the pressure plate rotates relative to the clutch center, and at least a portion of the protrusion is configured to overlap with the center-side recess when viewed along the axis when the center-side slipper cam surface and the pressure-side slipper cam surface are in contact.

13. The clutch device according to claim 9, wherein the projection extends from the pressure-side fitting tooth and beyond the first end of the pressure-side fitting tooth in the first direction, and at least a portion of the projection is configured to overlap with the center-side recess when viewed along the axis.

14. The clutch device according to claim 13, wherein when the pressure plate is in its closest position to the clutch center, at least a portion of the protrusion is configured to overlap with the center-side recess when viewed along the axis.

15. The clutch device according to claim 13, wherein the pressure plate has a plurality of pressure-side cam portions having a pressure-side assist cam surface, the clutch center has a plurality of center-side cam portions having a center-side assist cam surface facing the pressure-side assist cam surface in the circumferential direction, the pressure-side assist cam surface and the center-side assist cam surface are configured to increase the pressing force between the input-side rotating plate and the output-side rotating plate by generating a force in a direction that brings the pressure plate closer to the clutch center when the pressure plate rotates relative to the clutch center, and when the pressure-side assist cam surface and the center-side assist cam surface are in contact, at least a part of the protrusion is configured to overlap with the center-side recess when viewed along the axis.

16. The clutch device according to claim 13, wherein the pressure plate has a plurality of pressure-side cam portions having pressure-side slipper cam surfaces, the clutch center has a plurality of center-side cam portions having center-side slipper cam surfaces facing the pressure-side slipper cam surfaces, the pressure-side slipper cam surfaces and the center-side slipper cam surfaces are configured to reduce the pressing force between the input-side rotating plate and the output-side rotating plate when the pressure plate rotates relative to the clutch center, and at least a portion of the protrusion is configured to overlap with the center-side recess when viewed along the axis when the center-side slipper cam surface and the pressure-side slipper cam surface are in contact.

17. The clutch center has a through hole formed radially outward from the output shaft and penetrating in the axial direction of the output shaft; the pressure plate has a plurality of pressure-side cam portions having a pressure-side assist cam surface; the clutch center has a plurality of center-side cam portions located radially outward from the output shaft holding portion and having a center-side assist cam surface facing the pressure-side assist cam surface in the circumferential direction; the pressure-side assist cam surface and the center-side assist cam surface are configured to increase the pressing force between the input-side rotating plate and the output-side rotating plate by generating a force in a direction that brings the pressure plate closer to the clutch center when the pressure plate rotates relative to the clutch center; the pressure plate has a projection extending from the cylindrical portion in the first direction beyond the end of the cylindrical portion in the first direction; The clutch device according to claim 1, wherein when the pressure-side assist cam surface and the center-side assist cam surface are in contact, at least a portion of the protrusion is positioned inside the through hole when viewed in the axial direction.

18. The clutch device according to claim 17, wherein the projection extends from the pressure-side fitting tooth and from the end of the pressure-side fitting tooth in the first direction beyond that end.

19. The clutch device according to claim 9 or 17, wherein the protrusion is formed in such a shape that its length in the circumferential direction of the output shaft decreases as it approaches the first direction.

20. The clutch device according to claim 1, wherein the pressure plate has a projection extending from the cylindrical portion in the first direction beyond the end of the cylindrical portion in the first direction, and the projection has an outer peripheral surface that extends inward in the radial direction as it approaches the first direction.

21. The clutch device according to claim 20, wherein the projection extends from the pressure-side fitting tooth and from the end of the pressure-side fitting tooth in the first direction in the first direction.

22. The clutch device according to claim 20, wherein the protruding portion is formed in such a shape that its radial length decreases as it approaches the first direction.

23. The clutch device according to claim 1, further comprising the clutch housing, wherein the pressure plate has a projection extending from the cylindrical portion in a first direction beyond the first end of the cylindrical portion, the projection has an outer peripheral surface extending inward in the radial direction as it approaches the first direction, the clutch housing has a side wall located radially outward from the projection and extending in a second direction, the side wall of the clutch housing has an inner peripheral surface facing the projection in the radial direction, and when the clutch housing and the pressure plate are arranged coaxially, the radial distance between the edge of the outer peripheral surface of the projection on the first direction side and the inner peripheral edge of the output side rotating plate is longer than the radial distance between the outer peripheral edge of the output side rotating plate and the inner peripheral surface of the clutch housing.

24. The clutch device according to claim 23, wherein the radial distance between the pressure-side mating teeth and the inner peripheral edge of the output-side rotating plate is shorter than the radial distance between the outer peripheral edge of the output-side rotating plate and the inner peripheral surface of the clutch housing.

25. The clutch housing further comprises the pressure plate having a projection from the cylindrical portion that extends in the first direction beyond the first end of the cylindrical portion, the projection having an outer peripheral surface that extends inward in the radial direction as it approaches the first direction, the clutch housing having a side wall located radially outward from the projection and extending in the second direction, the side wall of the clutch housing having an inner peripheral surface facing the projection in the radial direction, the output side rotating plate being formed in an annular shape, the output side rotating plate being formed to project radially inward from the inner peripheral surface of the output side rotating plate and having a plurality of rotating plate fitting teeth arranged in the circumferential direction of the output shaft, and rotating plate grooves formed between adjacent rotating plate fitting teeth, The clutch device according to claim 1, wherein when the output rotating plate is offset with respect to the axis in a first radial direction, the edge of the outer circumferential surface of the protrusion located on the second radial direction side opposite to the first radial direction is positioned radially inward from the rotating plate groove located on the second radial direction side.

26. The clutch device according to claim 3, wherein the end of the annular wall in the first direction is located on the second direction side of the center-side recess when the pressure plate is in contact with the stopper plate.

27. The clutch device according to claim 1, wherein the pressure plate has a plurality of pressure-side cam portions having a pressure-side assist cam surface, the clutch center is located radially outward from the output shaft holding portion and has a plurality of center-side cam portions having a center-side assist cam surface facing the pressure-side assist cam surface in the circumferential direction of the output shaft, the pressure-side assist cam surface and the center-side assist cam surface are configured to increase the pressing force between the input-side rotating plate and the output-side rotating plate by generating a force in a direction that brings the pressure plate closer to the clutch center when the pressure plate rotates relative to the clutch center, and the end of the annular wall in the first direction is located on the first direction side of the end of the center-side cam portion in the first direction when the pressure plate is in contact with the stopper plate.

28. The clutch device according to claim 1, wherein the clutch center is located radially outward from the center-side fitting portion and has a center-side pressing surface that sandwiches the input-side rotating plate and the output-side rotating plate between itself and the pressure plate, and the end of the center-side fitting portion in the first direction is located on the first direction side of the center-side pressing surface.

29. The clutch device according to claim 1, wherein the portion of the annular wall extending from the end of the annular wall in the first direction in the second direction constitutes a pressure-side fitting portion that is slidably fitted with the center-side fitting portion in the axial direction.

30. The clutch device according to claim 29, wherein at least a portion of the pressure-side fitting portion is located on the first direction side of the end of the clutch spring in the first direction.

31. The clutch device according to claim 30, wherein all of the pressure-side fitting portions are located on the first direction side of the end of the clutch spring in the first direction.

32. The clutch device according to claim 1, wherein the pressure plate holds all of the plurality of output-side rotating plates.

33. The clutch device according to claim 1, wherein the pressure plate has a projection extending from the cylindrical portion in a first direction beyond the end of the cylindrical portion in the first direction, the clutch center has a center-side pressing surface that sandwiches the input-side rotating plate and the output-side rotating plate between itself and the pressure plate, and the end of the projection in the first direction is located on the side of the center-side pressing surface in the first direction when the pressure plate is in contact with the stopper plate.

34. The clutch device according to claim 33, wherein the projection extends in the first direction from the end face in the first direction of the pressure-side mating tooth.

35. A clutch device for transmitting or interrupting the rotational driving force of an input shaft to an output shaft, comprising: a clutch center housed in a clutch housing that rotates upon receiving the rotational driving force and holds a plurality of input-side rotating plates arranged in an axial direction which is the direction of the axis of the output shaft, and which rotates together with the output shaft; a plurality of output-side rotating plates arranged alternately with the input-side rotating plates in the axial direction; a pressure plate that can approach or move away from the clutch center in the axial direction, holds the output-side rotating plates, and presses the input-side rotating plates and the output-side rotating plates; a clutch spring that biases the pressure plate in the first direction, where the direction in which the pressure plate approaches the clutch center along the axial direction is defined as the first direction, and the direction in which the pressure plate moves away from the clutch center along the axial direction is defined as the second direction; A clutch device comprising: a stopper plate fixed to the clutch center and in contact with the pressure plate to restrict the pressure plate from moving away from the clutch center by a predetermined distance or more in the second direction, wherein the clutch center has an output shaft holding portion through which the output shaft is inserted, and a center-side fitting portion located radially outward from the output shaft holding portion and into which the pressure plate is slidably fitted in the axial direction, wherein the pressure plate has a cylindrical portion having an annular wall formed in a cylindrical shape extending in the first direction, and pressure-side fitting teeth protruding radially from the annular wall and holding the output-side rotating plate, and the end of the annular wall in the first direction is located in the first direction more than the end of the center-side fitting portion in the second direction when the pressure plate is in its furthest distance from the clutch center.

36. The clutch device according to claim 35, wherein the annular wall of the pressure plate is fitted onto the center-side fitting portion.

37. The clutch device according to claim 35, wherein the portion of the annular wall extending from the end of the annular wall in the first direction in the second direction constitutes a pressure-side fitting portion that is slidably fitted with the center-side fitting portion in the axial direction, and the end of the pressure-side fitting portion in the first direction is located on the first direction side of the center-side fitting portion than the end of the center-side fitting portion in the second direction when the pressure plate is in the state furthest distance from the clutch center.

38. The clutch device according to claim 35, wherein the pressure plate holds all of the plurality of output-side rotating plates.

39. The clutch device according to claim 35, wherein the pressure plate has a projection extending from the cylindrical portion in a first direction beyond the end of the cylindrical portion in the first direction, the clutch center has a center-side pressing surface that sandwiches the input-side rotating plate and the output-side rotating plate between itself and the pressure plate, and the end of the projection in the first direction is located on the side of the center-side pressing surface in the first direction when the pressure plate is in contact with the stopper plate.

40. The clutch device according to claim 39, wherein the projection extends in the first direction from the end face in the first direction of the pressure-side mating tooth.

41. A clutch device for transmitting or interrupting the rotational driving force of an input shaft to an output shaft, comprising: a clutch center housed in a clutch housing that rotates upon receiving the rotational driving force and holds a plurality of input-side rotating plates arranged in an axial direction which is the direction of the axis of the output shaft, and which rotates together with the output shaft; a plurality of output-side rotating plates arranged alternately with the input-side rotating plates in the axial direction; a pressure plate provided so as to be able to approach and move away from the clutch center in the axial direction and to be rotatable relative to the clutch center, and which holds the output-side rotating plates and presses the input-side rotating plates and the output-side rotating plates; a clutch spring that biases the pressure plate in the first direction, where the direction in which the pressure plate approaches the clutch center along the axial direction is defined as the first direction, and the direction in which the pressure plate moves away from the clutch center along the axial direction is defined as the second direction; The clutch center comprises a stopper plate fixed to the clutch center and in contact with the pressure plate, thereby restricting the pressure plate from moving away from the clutch center by a predetermined distance or more in the second direction, the clutch center comprises an output shaft holding portion through which the output shaft is inserted, a center-side fitting portion located radially outward from the output shaft holding portion and into which the pressure plate is slidably fitted in the axial direction, a center-side pressing surface located radially outward from the center-side fitting portion and sandwiching the input-side rotating plate and the output-side rotating plate between itself and the pressure plate, and a plurality of center-side cam portions having center-side assist cam surfaces located radially outward from the output shaft holding portion, the pressure plate comprises a plurality of pressure cam portions having pressure-side assist cam surfaces facing the center-side assist cam surfaces in the circumferential direction. The pressure-side assist cam surface and the center-side assist cam surface are configured to increase the pressing force between the input-side rotating plate and the output-side rotating plate by generating a force in a direction that brings the pressure plate closer to the clutch center when the pressure plate rotates relative to the clutch center.A clutch device in which, when the pressure-side assist cam surface and the center-side assist cam surface are in contact, at least a portion of the pressure plate is located on the first direction side of the center-side pressing surface of the clutch center.

42. The clutch device according to claim 41, wherein the pressure plate has a cylindrical portion comprising a cylindrical annular wall extending in the first direction and pressure-side fitting teeth projecting radially from the annular wall and holding the output-side rotating plate, and a projection extending from the cylindrical portion in the first direction beyond the end of the cylindrical portion in the first direction, wherein the end of the projection in the first direction is located on the side of the center-side pressing surface in the first direction when the pressure plate is in contact with the stopper plate.

43. The clutch device according to claim 42, wherein the projection extends in the first direction beyond the end of the pressure-side mating tooth in the first direction.

44. The clutch device according to claim 42, wherein the annular wall is located on the second direction side of the center-side pressing surface when the pressure plate is in contact with the stopper plate.

45. The clutch device according to claim 44, wherein a plurality of protrusions are provided in the circumferential direction of the output shaft, and the total length obtained by summing the circumferential lengths of the plurality of protrusions is shorter than the length of half the circumference of the annular wall.

46. ​​The clutch device according to claim 42, wherein the protruding portion is formed in such a shape that its length in the circumferential direction of the output shaft decreases as it approaches the first direction.

47. The clutch device according to claim 42, wherein the protruding portion has an outer peripheral surface that extends inward in the radial direction as it approaches the first direction.

48. The clutch device according to claim 47, wherein the protruding portion is formed in such a shape that its radial length decreases as it approaches the first direction.

49. The clutch device according to claim 42, wherein the projection extends in the first direction from the end face in the first direction of the pressure-side fitting tooth.

50. The clutch device according to claim 41, further comprising the clutch housing, wherein the pressure plate has a cylindrical portion having a cylindrical annular wall extending in the first direction and pressure-side fitting teeth projecting radially from the annular wall and holding the output-side rotating plate, and a projection from the cylindrical portion extending in the first direction beyond the end of the cylindrical portion in the first direction, the projection having an outer peripheral surface that extends radially inward as it approaches the first direction, the clutch housing has a side wall located radially outward from the projection and extending in the second direction, the side wall of the clutch housing has an inner peripheral surface facing radially from the projection, and when the clutch housing and the pressure plate are arranged coaxially, the radial distance between the edge of the outer peripheral surface of the projection on the first direction side and the inner peripheral edge of the output-side rotating plate is longer than the radial distance between the outer peripheral edge of the output-side rotating plate and the inner peripheral surface of the clutch housing.

51. The clutch device according to claim 50, wherein the radial distance between the pressure-side mating teeth and the inner peripheral edge of the output-side rotating plate is shorter than the radial distance between the outer peripheral edge of the output-side rotating plate and the inner peripheral surface of the clutch housing.

52. The clutch housing further comprises the pressure plate having a cylindrical portion having a cylindrical annular wall extending in the first direction and pressure-side fitting teeth projecting radially from the annular wall and holding the output-side rotating plate, and a projection from the cylindrical portion extending in the first direction beyond the end of the cylindrical portion in the first direction, the projection having an outer peripheral surface that extends radially inward as it approaches the first direction, the clutch housing has a side wall located radially outward from the projection and extending in the second direction, the side wall of the clutch housing has an inner peripheral surface facing radially from the projection, the output-side rotating plate is formed in an annular shape, the output-side rotating plate has a plurality of rotating plate fitting teeth arranged in the circumferential direction of the output shaft and formed to project radially inward from the inner peripheral surface of the output-side rotating plate, and rotating plate grooves formed between adjacent rotating plate fitting teeth, The clutch device according to claim 41, wherein when the output rotating plate is offset with respect to the axis in a first radial direction, the edge of the outer circumferential surface of the protrusion located on the second radial direction side opposite to the first radial direction is positioned radially inward from the rotating plate groove located on the second radial direction side.

53. The clutch device according to claim 42, wherein the end of the protruding portion in the first direction is located on the side of the center pressing surface in the first direction when the pressure plate is in contact with the stopper plate.

54. The clutch device according to claim 41, wherein when the pressure plate is in contact with the stopper plate, at least a portion of the pressure plate is located on the side in the first direction of the end of the center-side cam portion in the first direction.

55. The clutch device according to claim 54, wherein in all states from the state in which the pressure plate is positioned furthest to the first direction to the state in which the pressure plate is positioned furthest to the second direction, at least a portion of the pressure plate is positioned furthest to the first direction than the end of the center-side cam portion in the first direction.

56. The clutch device according to claim 41, wherein the pressure plate holds all of the plurality of output-side rotating plates.

Images