Clutch device

Abstract

A clutch device 10 comprises: a clutch spring 25 that urges a pressure plate 70 in a first direction D1; and a stopper plate 100 that keeps the pressure plate 70 from separating from a clutch center 40 by a prescribed distance or more in a second direction D2. The stopper plate 100 has a first contact surface 102 that is at a surface 100D1 on the first direction D1 side, is sloped in the circumferential direction S, and contacts an end part 25B in the second direction D2 of the clutch spring 25, and a pressure-side protrusion 88 that can come into surface contact with the stopper plate 100 is provided at a surface 70D2 on the second direction D2 side of the pressure plate 70 and protrudes in the second direction D2.

Description

Clutch device

[0001] The present invention relates to a clutch device.

[0002] Conventionally, vehicles such as motorcycles have been equipped with clutch devices. For example, Patent Document 1 discloses a clutch device including a clutch center that holds an output rotating plate, a pressure plate that is capable of moving toward and away from the clutch center, and a clutch spring that urges the pressure plate toward the clutch center. The clutch spring is housed in a housing formed in the pressure plate. One end of the clutch spring contacts the pressure plate, and the other end of the clutch spring contacts a stopper plate fixed to the clutch center.

[0003] Japanese Patent No. 6894792

[0004] In Patent Document 1, the other end of the clutch spring contacts a surface of the stopper plate perpendicular to the axial direction of the output shaft. In such cases, depending on the vehicle model, the pressure plate may suddenly approach the clutch center, suddenly pressing the input and output rotating plates together. Furthermore, depending on the vehicle model, a free-running sensation may occur during sudden acceleration. That is, the clutch may suddenly engage unintentionally, or a free-running sensation may occur during sudden acceleration. Therefore, the applicant of the present application has been studying ways to prevent the pressure plate from suddenly approaching the clutch center in some models and to reduce the free-running sensation during sudden acceleration in other models by inclining the surface of the stopper plate that contacts the other end of the clutch spring. However, in such a configuration, the pressure plate makes point or line contact with the stopper plate, which applies an excessive load to the stopper plate, potentially resulting in damage (e.g., buckling) of the stopper plate.

[0005] The present invention has been made in consideration of these points, and its purpose is to provide a clutch device that can prevent the pressure plate from suddenly approaching the clutch center, reduce the feeling of free running during sudden acceleration, and prevent damage to the stopper plate.

[0006] The clutch device according to the present invention is a clutch device that transmits or cuts off the rotational driving force of an input shaft to an output shaft, and includes: a clutch center that is accommodated in a clutch housing that holds a plurality of input side rotating plates that are rotationally driven by the rotational drive of the input shaft and that rotates together with the output shaft; a pressure plate that is arranged to be able to approach or move away from the clutch center and to be rotatable relative to the clutch center, that holds a plurality of output side rotating plates that are arranged alternately with the input side rotating plates, and that can press the input side rotating plates and the output side rotating plates; a clutch spring that urges the pressure plate in the first direction when the direction in which the pressure plate approaches the clutch center is defined as a first direction and the direction in which the pressure plate moves away from the clutch center is defined as a second direction; and a clutch spring that is fixed to the clutch center and is arranged to be able to come into contact with the pressure plate, and that urges the pressure plate away from the clutch center. and a stopper plate that prevents the clutch spring from moving away from the pressure plate by more than a predetermined distance in the second direction, wherein an end of the clutch spring in the first direction contacts the pressure plate and an end of the clutch spring in the second direction contacts the stopper plate, the pressure plate is recessed from the second direction toward the first direction and has an accommodating portion that accommodates the clutch spring, the stopper plate is provided on a surface on the first direction side and is inclined circumferentially and has a contact surface that contacts the end of the clutch spring in the second direction, and is provided with a stopper-side protrusion that is provided on the surface on the first direction side of the stopper plate, protrudes in the first direction, and is capable of surface contact with the pressure plate, or a pressure-side protrusion that is provided on the surface on the second direction side of the pressure plate, protrudes in the second direction, and is capable of surface contact with the stopper plate.

[0007] In the clutch device according to the present invention, the contact surface of the stopper plate is inclined in the circumferential direction and contacts the end of the clutch spring in the second direction. This prevents the pressure plate from suddenly approaching the clutch center and reduces the feeling of free running during sudden acceleration. The clutch device also includes a stopper-side protrusion that can come into surface contact with the pressure plate, or a pressure-side protrusion that can come into surface contact with the stopper plate. As a result, the pressure plate and the stopper plate come into surface contact via the stopper-side protrusion or the pressure-side protrusion, which distributes the load applied from the pressure plate to the stopper plate and prevents damage to the stopper plate.

[0008] Another clutch device according to the present invention is a clutch device that transmits or cuts off the rotational drive force of an input shaft to an output shaft, and includes: a clutch center that is accommodated in a clutch housing that holds a plurality of input side rotating plates that are rotationally driven by the rotational drive of the input shaft and that is rotationally driven together with the output shaft; a pressure plate that is arranged to be able to approach or move away from the clutch center and to be rotatable relative to the clutch center, that holds a plurality of output side rotating plates that are arranged alternately with the input side rotating plates, and that is capable of pressing the input side rotating plates and the output side rotating plates; a clutch spring that urges the pressure plate in the first direction, when the direction in which the pressure plate approaches the clutch center is defined as a first direction and the direction in which the pressure plate moves away from the clutch center is defined as a second direction; and a clutch spring that is fixed to the pressure plate and is arranged to be able to come into contact with the clutch center, and that urges the pressure plate against the clutch center. and a stopper plate that prevents the clutch spring from moving away from a clutch center in the second direction by more than a predetermined distance, wherein an end of the clutch spring in the first direction contacts the stopper plate and an end of the clutch spring in the second direction contacts the clutch center, the clutch center is recessed from the first direction toward the second direction and has an accommodating portion that accommodates the clutch spring, the stopper plate is provided on a surface on the second direction side, is inclined circumferentially, and has a contact surface that contacts the end of the clutch spring in the first direction, and is provided with a stopper-side protrusion that is provided on the surface on the second direction side of the stopper plate, protrudes in the second direction, and is capable of surface contact with the clutch center, or a center-side protrusion that is provided on the surface on the first direction side of the clutch center, protrudes in the first direction, and is capable of surface contact with the stopper plate.

[0009] In another clutch device according to the present invention, the contact surface of the stopper plate is inclined in the circumferential direction and contacts the end of the clutch spring in the first direction. This prevents the pressure plate from suddenly approaching the clutch center and reduces the feeling of free running during sudden acceleration. The clutch device also includes a stopper-side protrusion that can come into surface contact with the clutch center or a center-side protrusion that can come into surface contact with the stopper plate. As a result, the clutch center and the stopper plate come into surface contact via the stopper-side protrusion or the center-side protrusion, which distributes the load applied from the clutch center to the stopper plate and prevents damage to the stopper plate.

[0010] According to the present invention, a clutch device can be provided that can prevent the pressure plate from suddenly approaching the clutch center, reduce the feeling of free running during sudden acceleration, and prevent damage to the stopper plate.

[0011] FIG. 1 is a cross-sectional view of a clutch device according to the first embodiment. FIG. 2 is a perspective view of a clutch center according to the first embodiment. FIG. 3 is a plan view of the clutch center according to the first embodiment. FIG. 4 is a perspective view of a pressure plate according to the first embodiment. FIG. 5 is a plan view of the pressure plate according to the first embodiment. FIG. 6 is a perspective view of the pressure plate according to the first embodiment. FIG. 7 is a plan view of the pressure plate according to the first embodiment. FIG. 8 is a side view of the pressure plate according to the first embodiment. FIG. 9 is a perspective view of a stopper plate according to the first embodiment. FIG. 10 is a side view of the stopper plate according to the first embodiment. FIG. 11 is a schematic diagram illustrating the functions of a center-side assist cam surface and a pressure-side assist cam surface. FIG. 12 is a schematic diagram illustrating the functions of a center-side slipper cam surface and a pressure-side slipper cam surface. FIG. 13 is a cross-sectional view showing an assembled state of the clutch center, pressure plate, and stopper plate according to the first embodiment. FIG. 14 is a cross-sectional view showing a contact state between the pressure plate and the stopper plate according to the first embodiment. Fig. 15 is a cross-sectional view showing the assembled state of the clutch center, pressure plate, and stopper plate according to the second embodiment. Fig. 16 is a cross-sectional view showing the assembled state of the clutch center, pressure plate, and stopper plate according to the third embodiment. Fig. 17 is a cross-sectional view showing the assembled state of the clutch center, pressure plate, and stopper plate according to the fourth embodiment. Fig. 18 is a cross-sectional view showing the assembled state of the clutch center, pressure plate, and stopper plate according to the fifth embodiment. Fig. 19 is a cross-sectional view showing the assembled state of the clutch center, pressure plate, and stopper plate according to the sixth embodiment.

[0012] Hereinafter, an embodiment of a clutch device according to the present invention will be described with reference to the drawings. It should be noted that the embodiment described here is not intended to limit the present invention in any way. Furthermore, the same reference numerals are used to designate components and parts that perform the same functions, and redundant descriptions will be omitted or simplified as appropriate.

[0013] <First embodiment> Fig. 1 is a cross-sectional view of a clutch device 10 according to this embodiment. The clutch device 10 is provided on a vehicle such as a motorcycle. The clutch device 10 is a device that transmits or cuts off the rotational driving force of an input shaft (crankshaft) of a driving source such as an engine of the motorcycle to an output shaft 15. The clutch device 10 is a device that transmits or cuts off the rotational driving force of the input shaft to a driving wheel (rear wheel) via the output shaft 15. The clutch device 10 is disposed between the engine and the transmission.

[0014] In the following description, the direction in which the pressure plate 70 of the clutch device 10 approaches and moves away from the clutch center 40 is referred to as direction D, the direction in which the pressure plate 70 approaches the clutch center 40 is referred to as a first direction D1, and the direction in which the pressure plate 70 moves away from the clutch center 40 is referred to as a second direction D2. The circumferential direction (i.e., the rotational direction) of the clutch center 40 and the pressure plate 70 is referred to as a circumferential direction S, the direction from one pressure side cam portion 90 to the other pressure side cam portion 90 with respect to the circumferential direction S is referred to as a first circumferential direction S1 (see FIG. 5), and the direction from the other pressure side cam portion 90 to one pressure side cam portion 90 is referred to as a second circumferential direction S2 (see FIG. 5). 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, the axial direction of the pressure plate 70, and the axial direction of the stopper plate 100 are the same as direction D. The pressure plate 70 and the clutch center 40 rotate in a first circumferential direction S1. However, this direction is merely defined for the convenience of explanation and does not limit the installation mode of the clutch device 10 or the present invention in any way.

[0015] 1, the clutch device 10 includes an output shaft 15, an input rotating plate 20, an output rotating plate 22, a clutch housing 30, a clutch center 40, a pressure plate 70, a stopper plate 100, and a clutch spring 25. The clutch device 10 is a so-called internal-disengagement type clutch device.

[0016] As shown in Figure 1, the output shaft 15 is a hollow shaft body. One end of the output shaft 15 rotatably supports an input gear 35 and a clutch housing 30 (described later) via a needle bearing 15A. The output shaft 15 fixedly supports a clutch center 40 via a nut 15B. That is, 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 transmission (not shown) of a motorcycle.

[0017] As shown in FIG. 1 , the output shaft 15 includes a hollow portion 15H containing a push rod 16A and a push member 16B adjacent to the push rod 16A. The hollow portion 15H functions as a clutch oil passage. Clutch oil flows through the output shaft 15, i.e., the hollow portion 15H. The push rod 16A and the push member 16B are slidably disposed within the hollow portion 15H of the output shaft 15. One end (the left end in the figure) of the push rod 16A is connected to a clutch mechanism (e.g., a clutch operating lever or operating button) of the motorcycle. When the rider operates the clutch, the push rod 16A slides within the hollow portion 15H and presses the push member 16B in the second direction D2. A portion 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 the push member 16B are formed to have a smaller inner diameter than the hollow portion 15H, ensuring the flow of clutch oil within the hollow portion 15H.

[0018] The clutch housing 30 is made of an aluminum alloy and has a cylindrical shape with a bottom. As shown in FIG. 1 , the clutch housing 30 has a bottom wall 31 formed in a substantially circular shape and a side wall 33 extending in the second direction D2 from an edge of the bottom wall 31. The clutch housing 30 holds a plurality of input side rotating plates 20.

[0019] 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 a rivet 35B via a torque damper 35A. The input gear 35 meshes with a drive gear (not shown) that rotates when the input shaft of the engine is rotated. The input gear 35 rotates integrally with the clutch housing 30, independently of the output shaft 15.

[0020] The input side rotating plate 20 is rotationally driven by the rotational drive of the input shaft. As shown in Fig. 1, the input side rotating plate 20 is held on the inner peripheral surface of 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 (i.e., direction D). The input side rotating plate 20 is provided so as to be rotatable integrally with the clutch housing 30.

[0021] The input side rotating plate 20 is a member that is pressed against the output side rotating plate 22. The input side rotating plate 20 is formed in an annular shape. The input side rotating plate 20 is formed by aluminum die-casting. Friction material (not shown) made of multiple pieces of paper is attached to the front and back surfaces of the input side rotating plate 20. Grooves several hundred microns deep are formed between the friction material to retain clutch oil.

[0022] As shown in FIG. 1 , the clutch center 40 is housed in the clutch housing 30. The clutch center 40 is disposed concentrically with the clutch housing 30. The clutch center 40 has a cylindrical main body 42 and a flange 68 extending radially outward from the outer peripheral edge of the main body 42. The clutch center 40 holds the input side rotating plate 20 and a plurality of output side rotating plates 22 arranged alternately in direction D. The clutch center 40 is driven to rotate together with the output shaft 15.

[0023] As shown in Figure 2, the main body 42 includes an annular base wall 43, an outer peripheral wall 45 located radially outward of the base wall 43 and extending in the second direction D2, an output shaft holding portion 50 provided in the center of the base wall 43, and a plurality of center side cam portions 60 connected to the base wall 43 and the outer peripheral wall 45.

[0024] As shown in Fig. 2, the output shaft holding portion 50 is formed in a cylindrical shape. The output shaft holding portion 50 is formed with an insertion hole 51 into which the output shaft 15 (see Fig. 1) is inserted and spline-fitted. The insertion hole 51 is formed to penetrate the base wall 43. An inner circumferential surface 50A of the output shaft holding portion 50 that forms the insertion hole 51 has a plurality of spline grooves formed along the axial direction. The output shaft 15 is connected to the output shaft holding portion 50 (see Fig. 1).

[0025] As shown in FIG. 2 , the outer peripheral wall 45 of the clutch center 40 is disposed radially outward of the output shaft holding portion 50. A spline fitting portion 46 is provided on the outer peripheral surface of the outer peripheral wall 45. The spline fitting portion 46 has a plurality of center-side fitting teeth 47 extending in the axial direction of the clutch center 40 along the outer peripheral surface of the outer peripheral wall 45, and a plurality of spline grooves 48 formed between adjacent center-side fitting teeth 47 and extending in the axial direction of the clutch center 40. The center-side fitting teeth 47 hold the output-side rotating plate 22. The center-side fitting teeth 47 are aligned in the circumferential direction S. The center-side fitting teeth 47 are formed at equal intervals in the circumferential direction S. The center-side fitting teeth 47 are formed in the same shape. The center-side fitting teeth 47 protrude radially outward from the outer peripheral surface of the outer peripheral wall 45. The outer peripheral surface of the center-side fitting teeth 47 is formed substantially parallel to the axis of the output shaft 15 .

[0026] The output side rotating plate 22 is held by the spline fitting portion 46 of the clutch center 40 and the pressure plate 70. A portion of the output side rotating plate 22 is held by the center side fitting teeth 47 and the spline grooves 48 of the clutch center 40 through spline fitting. Another portion of the output side rotating plate 22 is held by the pressure side fitting teeth 77 (see FIG. 4 ) of the pressure plate 70, which will be described later. The output side rotating plate 22 is provided so as to be displaceable along the axial direction of the clutch center 40. The output side rotating plate 22 is provided so as to be rotatable integrally with the clutch center 40. The output side rotating plate 22 is provided so as to be displaceable along the axial direction of the pressure plate 70. The output side rotating plate 22 is provided so as to be rotatable integrally with the pressure plate 70.

[0027] The output side rotating plate 22 is a member that is pressed against the input side rotating plate 20. The output side rotating plate 22 is formed in an annular shape. The output side rotating plate 22 is formed by punching out an SPCC thin plate into an annular shape. 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 may be provided on both the input side rotating plate 20 and the output side rotating plate 22.

[0028] As shown in FIG. 2 , the center-side cam portion 60 is formed in a platform shape with a cam surface made up of an inclined surface that constitutes an Assist & Slipper (registered trademark) mechanism that generates an assist torque, which is a force that increases the pressing force (pressure contact force) between the input-side rotating plate 20 and the output-side rotating plate 22, or a slipper torque, which is a force that quickly separates the input-side rotating plate 20 and the output-side rotating plate 22, resulting in a transition to a half-clutch state. The center-side cam portion 60 is formed to protrude from the base wall 43 in the second direction D2. As shown in FIG. 3 , 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.

[0029] As shown in FIG. 3 , the center-side cam portion 60 is located radially outward of the output shaft holding portion 50. The center-side cam portion 60 has a center-side assist cam surface 60A and a center-side slipper cam surface 60S. The center-side assist cam surface 60A is configured to generate a force in a direction from the pressure plate 70 toward the clutch center 40 (here, the first direction D1) when rotating relative to the pressure plate 70 in order to increase the pressing force (pressure contact force) between the input side rotating plate 20 and the output side rotating plate 22. In this embodiment, when the 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. Note that the pressure plate 70 may be physically displaced relative to the clutch center 40. The center-side slipper cam surface 60S is configured to move the pressure plate 70 away from the clutch center 40 in order to reduce the pressing force (pressure contact force) between the input-side rotating plate 20 and the output-side rotating plate 22 when rotating relative to the pressure plate 70. In the center-side cam portions 60 adjacent to each other in the circumferential direction S, 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 are arranged opposite each other in the circumferential direction S.

[0030] As shown in FIG. 2 , the clutch center 40 has multiple boss portions 54 (three in this embodiment). The boss portions 54 are members that support the stopper plate 100 (see FIG. 1 ). The multiple 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 (i.e., toward the second direction D2). The boss portions 54 are provided on the center-side cam portion 60. The boss portions 54 are located between the center-side assist cam surface 60A and the center-side slipper cam surface 60S in the rotational direction S. A threaded hole 54H is formed in the boss portion 54. The threaded hole 54H extends in the axial direction of the clutch center 40. The bolts 28 (see FIG. 1) used to fix the stopper plate 100 to the clutch center 40 are inserted into the screw holes 54H.

[0031] 2 and 3, the clutch center 40 has a center-side cam hole 43H that penetrates a portion of the base wall 43 in the axial direction of the output shaft 15. The center-side cam hole 43H extends radially from the side of the output shaft holding portion 50 to the outer peripheral wall 45. The center-side cam hole 43H is formed between a center-side assist cam surface 60A of one center-side cam portion 60 and a center-side slipper cam surface 60S of the other center-side cam portion 60. When viewed in the axial direction of the clutch center 40, the center-side assist cam surface 60A and a portion of the center-side cam hole 43H overlap.

[0032] As shown in FIG. 1 , the pressure plate 70 is disposed so as to be able to move toward or away from the clutch center 40 and 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 disposed concentrically with the clutch center 40 and the clutch housing 30. The pressure plate 70 has a main body 72 and a flange 98 that connects to the outer peripheral edge of the main body 72 on the second direction D2 side and extends radially outward. The main body 72 protrudes in the first direction D1 beyond the flange 98. The flange 98 is located at the outer diameter end of the pressure plate 70. The flange 98 is located radially outward beyond a cylindrical portion 80 (see also FIG. 4 ), which will be described later. The pressure plate 70 holds a plurality of output side rotating plates 22 that are arranged alternately with the input side rotating plates 20. The flange 98 is configured to be able to press against the input side rotating plate 20 and the output side rotating plate 22.

[0033] 4, the main body 72 includes a cylindrical portion 80, a plurality of pressure-side cam portions 90, and a spring accommodating portion 84 (see FIG. 6). The spring accommodating portion 84 is an example of an accommodating portion.

[0034] 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. The cylindrical portion 80 accommodates the release bearing 18 (see FIG. 1). The cylindrical portion 80 is a portion that receives the pressing force from the push member 16B. The cylindrical portion 80 is a portion that receives the clutch oil that flows out from the tip portion 15T of the output shaft 15.

[0035] As shown in FIG. 4 , the pressure-side cam portion 90 is formed in a platform shape having a cam surface made up of an inclined surface that constitutes an Assist & Slipper (registered trademark) mechanism that slides on the center-side cam portion 60 to generate assist torque or slipper torque. The pressure-side cam portion 90 is formed to protrude in the first direction D1 beyond the flange 98. As shown in FIG. 5 , 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.

[0036] As shown in FIG. 5 , the pressure-side cam portion 90 is located radially outward of the cylindrical portion 80. The pressure-side cam portion 90 has a pressure-side assist cam surface 90A (see also FIGS. 6 and 7 ) and a pressure-side slipper cam surface 90S. The pressure-side assist cam surface 90A is configured to be able to come into contact with the center-side assist cam surface 60A. The pressure-side assist cam surface 90A is configured to generate a force in a direction from the pressure plate 70 toward the clutch center 40 (here, the first direction D1) to increase the pressing force (pressure 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 during acceleration, etc. The pressure-side slipper cam surface 90S is configured to be able to come into contact with the center-side slipper cam surface 60S. The pressure-side slipper cam surface 90S is configured to move the pressure plate 70 away from the clutch center 40 when the pressure plate 70 rotates relative to the clutch center 40 during deceleration, etc., in order to reduce the pressing force (pressure contact force) between the input-side rotating plate 20 and the output-side rotating plate 22. In the pressure-side cam portions 90 adjacent to each other in 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.

[0037] Here, the action of the center-side cam portion 60 and the pressure-side cam portion 90 will be described. When the engine speed increases and the rotational driving force input to the input gear 35 and the clutch housing 30 can be transmitted to the output shaft 15 via the clutch center 40, a rotational force in the first circumferential direction S1 is applied to the pressure plate 70, as shown in FIG. 11 . Therefore, a force in the first direction D1 is generated on the pressure plate 70 due to the action of the center-side assist cam surface 60A and the pressure-side assist cam surface 90A. As a result, the pressure plate 70 moves in a direction (first direction D1) that brings it closer to the clutch center 40, thereby increasing the pressure contact force between the input-side rotating plate 20 and the output-side rotating plate 22.

[0038] On the other hand, when the rotational speed of the output shaft 15 exceeds the rotational speed of the input gear 35 and the clutch housing 30 and back torque is generated, a rotational force in the first circumferential direction S1 is applied to the clutch center 40, as shown in Figure 12. As a result, the action of the center-side slipper cam surface 60S and the pressure-side slipper cam surface 90S moves the pressure plate 70 in the second direction D2, releasing the pressure contact force between the input-side rotating plate 20 and the output-side rotating plate 22. This makes it possible to avoid problems with the engine and transmission due to back torque.

[0039] As shown in Figures 4 and 5, the pressure plate 70 has a pressure-side cam hole 73H that penetrates a portion of the main body 72 in the axial direction of the output shaft 15. The pressure-side cam hole 73H is located radially outward of the cylindrical portion 80. The pressure-side cam hole 73H extends radially from the side of the cylindrical portion 80 to a position radially outward of the pressure-side cam portion 90. 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 Figures 5 and 7, when viewed in the axial direction of the pressure plate 70, the pressure-side assist cam surface 90A and a portion of the pressure-side cam hole 73H overlap. When the clutch center 40 and the pressure plate 70 are combined, the boss portion 54 of the clutch center 40 is positioned within the pressure-side cam hole 73H when viewed in the axial direction of the pressure plate 70. The pressure-side cam hole 73H is an example of a through hole.

[0040] As shown in FIG. 4 , the pressure plate 70 has a plurality of pressure-side fitting teeth 77 formed on the outer circumferential surface of the main body 72. The pressure-side fitting teeth 77 hold at least one output-side rotating plate 22. The pressure-side fitting teeth 77 are located closer to the first direction D1 than the flange 98. The pressure-side fitting teeth 77 are located radially outward from the cylindrical portion 80. The pressure-side fitting teeth 77 are located radially outward from the pressure-side cam portion 90. The pressure-side fitting teeth 77 are located radially outward from the pressure-side cam portion 90. The pressure-side fitting teeth 77 are aligned in the circumferential direction S. The pressure-side fitting teeth 77 are arranged at equal intervals in the circumferential direction S. Note that in this embodiment, some of the pressure-side fitting teeth 77 have been removed, increasing the spacing between the removed portions, but the remaining adjacent pressure-side fitting teeth 77 are arranged at equal intervals.

[0041] As shown in FIGS. 6 and 7 , the spring accommodating portion 84 is formed in the pressure-side cam portion 90. The spring accommodating portion 84 is recessed from the second direction D2 toward the first direction D1. The spring accommodating portion 84 is circular when viewed from the direction D. The spring accommodating portion 84 accommodates the clutch spring 25 (see FIG. 1 ). The spring accommodating portion 84 is aligned with the pressure-side assist cam surface 90A in the circumferential direction S. The spring accommodating portion 84 is positioned between the pressure-side assist cam surface 90A and the pressure-side slipper cam surface 90S in the circumferential direction S. As shown in FIG. 13 , the spring accommodating portion 84 holds the end 25A of the clutch spring 25 in the first direction D1 (described later). The spring accommodating portion 84 has a holding surface 84A that holds the end 25A in the first direction D1. The holding surface 84A is perpendicular to the axial direction of the output shaft 15. The spring accommodating portion 84 fixes the end 25A in the first direction D1 to the pressure plate 70.

[0042] As shown in FIG. 6 , the pressure plate 70 includes a pressure-side protrusion 88. The pressure-side protrusion 88 is provided so as to be able to come into surface contact with the stopper plate 100. The pressure-side protrusion 88 is provided so as to be able to come into surface contact with a first contact surface 102 (see FIG. 14 ) of the stopper plate 100. The pressure-side protrusion 88 is provided on a surface 70D2 of the pressure plate 70 on the second direction D2 side. Here, the pressure-side protrusion 88 is provided on a portion of the surface 70D2 of the pressure plate 70 on the second direction D2 side that is adjacent to the spring accommodating portion 84. The pressure-side protrusion 88 is formed integrally with the die-cast pressure plate 70. Note that the pressure-side protrusion 88 may be provided separately from the pressure plate 70 and attached to the pressure plate 70. The pressure-side protrusion 88 is located between the spring accommodating portion 84 and the pressure-side cam hole 73H in the circumferential direction S. The pressure-side protrusion 88 is located closer to the first circumferential direction S1 than the pressure-side cam hole 73H. The pressure-side protrusion 88 is located closer to the spring accommodating portion 84 in the second circumferential direction S2. The pressure-side protrusion 88 is located radially outward from the cylindrical portion 80. The pressure-side protrusion 88 is located radially inward from the flange 98. As shown in FIG. 7 , the pressure-side protrusion 88 is formed in a substantially rectangular shape. The pressure-side protrusion 88 may also be formed in a circular or elliptical shape. When viewed in the axial direction of the output shaft 15, the radial length LP1 of the pressure-side protrusion 88 is longer than the length LP2 of the pressure-side protrusion 88 in the circumferential direction S. When viewed in the axial direction of the output shaft 15, a circle CL1 whose center is the axis 15C of the output shaft 15 and which passes through the center 84C of the spring accommodating portion 84 overlaps with the pressure-side protrusion 88. As shown in FIG. 5 , the distance in the circumferential direction S between the pressure-side protrusion 88 and the pressure-side slipper cam surface 90S is shorter than the distance in the circumferential direction S between the pressure-side protrusion 88 and the pressure-side assist cam surface 90A. In other words, the pressure-side protrusion 88 is located closer to the pressure-side slipper cam surface 90S than the pressure-side assist cam surface 90A. When viewed in the axial direction of the output shaft 15, at least a portion of the pressure-side protrusion 88 overlaps with the pressure-side cam portion 90.When viewed in the axial direction of the output shaft 15, at least a portion of the pressure-side protrusion 88 overlaps with the pressure-side slipper cam surface 90S. As shown in FIG. 8 , the pressure-side protrusion 88 protrudes in the second direction D2 from the surface 70D2 on the second direction D2 side. The surface 88D2 on the second direction D2 side of the pressure-side protrusion 88 is perpendicular to the axial direction of the output shaft 15. The surface 88D2 on the second direction D2 side is flat. The surface 88D2 on the second direction D2 side is formed so as to be able to come into surface contact with the stopper plate 100 (more specifically, a second contact surface 104, which will be described later). Note that the surface 88D2 on the second direction D2 side may be inclined with respect to the axial direction of the output shaft 15 or may have a groove formed thereon.

[0043] As shown in FIG. 1 , the clutch spring 25 is accommodated in the spring accommodating portion 84. The clutch spring 25 biases the pressure plate 70 toward the clutch center 40. That is, the clutch spring 25 biases the pressure plate 70 in the first direction D1. The clutch spring 25 is, for example, a coil spring formed by spirally winding spring steel. The clutch spring 25 is, for example, cylindrical. An end 25A of the clutch spring 25 in the first direction D1 contacts the pressure plate 70. More specifically, the end 25A in the first direction D1 contacts the holding surface 84A of the spring accommodating portion 84. An end 25B of the clutch spring 25 in the second direction D2 contacts the stopper plate 100. More specifically, the end 25B in the second direction D2 contacts a first contact surface 102 (described later) of the stopper plate 100. 13 , end 25B in second direction D2 is in contact with first contact surface 102 that inclines in second direction D2 from pressure-side assist cam surface 90A to pressure-side slipper cam surface 90S, so that a force in the direction of arrow F1 in Fig. 13 is applied to pressure plate 70. This prevents pressure plate 70 from suddenly approaching clutch center 40 when the clutch changes from a clutch-off state (clutch disengaged state), i.e., a state in which input side rotating plate 20 and output side rotating plate 22 are separated and the rotational drive force of the input shaft is not transmitted to output shaft 15, to a clutch-on state (clutch engaged state), i.e., a state in which input side rotating plate 20 and output side rotating plate 22 are in pressure contact and the rotational drive force of the input shaft is transmitted to output shaft 15. In the clutch device 10 according to this embodiment, the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are prevented from suddenly contacting each other, thereby preventing the clutch from suddenly engaging. This also applies to the third, fifth, and sixth embodiments described below.

[0044] As shown in FIG. 1 , the stopper plate 100 is provided so as to be able to come into contact with the pressure plate 70. The stopper plate 100 is formed by bending a steel plate of uniform thickness. The stopper plate 100 is a member that prevents the pressure plate 70 from moving away from the clutch center 40 in the second direction D2 by more than a predetermined distance. For example, when the pressure plate 70 moves away from the clutch center 40 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 due to deceleration, or when the pressure plate 70 is moved in the second direction D2 by the driver's clutch operation, the pressure plate 70 comes into contact with the stopper plate 100. Furthermore, when the pressure plate 70 comes into contact with the stopper plate 100, the pressure-side protrusion 88 comes into contact with the stopper plate 100 first. The stopper plate 100 is fixed to the clutch center 40. The stopper plate 100 is fixed to the boss portion 54 of the clutch center 40 by the bolt 28. The stopper plate 100 is fastened and fixed to the boss portion 54 of the clutch center 40 via the bolt 28 with the clutch spring 25 accommodated in the spring accommodating portion 84. The stopper plate 100 is formed in a ring shape in a plan view.

[0045] As shown in FIGS. 9 and 10 , the stopper plate 100 includes an inclined portion 101 and a flat portion 103. The inclined portions 101 and the flat portions 103 are alternately arranged in the circumferential direction S. In this embodiment, three inclined portions 101 and three flat portions 103 are alternately arranged in succession. As shown in FIG. 13 , the inclined portion 101 has a first contact surface 102 provided on a surface 100D1 on the first direction D1 side of the stopper plate 100. The first contact surface 102 is an example of a contact surface. The first contact surface 102 is inclined in the circumferential direction S. The first contact surface 102 is formed so as to incline in the second direction D2 from the pressure-side assist cam surface 90A to the pressure-side slipper cam surface 90S. The first contact surface 102 contacts the end 25B of the clutch spring 25 in the second direction D2. 14 , the flat surface 103 has a second contact surface 104 provided on a surface 100D1 on the first direction D1 side of the stopper plate 100. The second contact surface 104 is perpendicular to the axial direction of the output shaft 15. The second contact surface 104 is provided to be able to come into surface contact with the pressure-side protrusion 88 of the pressure plate 70. In this way, when the pressure plate moves in the second direction D2 and comes into contact with the stopper plate 100, the pressure-side protrusion 88 of the pressure plate 70 comes into surface contact with the second contact surface 104 of the stopper plate 100, so that the load applied from the pressure plate 70 to the stopper plate 100 is dispersed.

[0046] As shown in FIG. 9 , the stopper plate 100 is formed with first through holes 111 and second through holes 112. The first through holes 111 and the second through holes 112 are arranged alternately in the circumferential direction S. In the present embodiment, three first through holes 111 and three second through holes 112 are arranged alternately. The diameter of the first through holes 111 is larger than the diameter of the second through holes 112. The first through holes 111 are holes for inserting a jig to prevent the clutch center 40 from rotating together with the nut 15B when the clutch center 40 is assembled to the output shaft 15 and the nut 15B is tightened. The second through holes 112 are holes for inserting the bolts 28.

[0047] As described above, in the clutch device 10 of this embodiment, the first contact surface 102 of the stopper plate 100 is inclined in the circumferential direction S and contacts the end 25B of the clutch spring 25 in the second direction D2. This prevents the pressure plate 70 from suddenly approaching the clutch center 40 and reduces the feeling of free running during sudden acceleration. The clutch device 10 also includes a pressure-side protrusion 88 that can come into surface contact with the stopper plate 100. This allows the pressure plate 70 and the stopper plate 100 to come into surface contact via the pressure-side protrusion 88, dispersing the load applied from the pressure plate 70 to the stopper plate 100 and preventing damage to the stopper plate 100. Furthermore, since the pressure-side protrusion 88 is provided on the pressure plate 70, it is easy to form the pressure-side protrusion 88.

[0048] In the clutch device 10 of this embodiment, the pressure-side protrusion 88 is provided on a portion of the surface 70D2 on the second direction D2 side of the pressure plate 70 that is adjacent to the spring accommodating portion 84. According to the above aspect, damage to the stopper plate 100 can be more reliably suppressed.

[0049] In the clutch device 10 of this embodiment, when viewed in the axial direction of the output shaft 15, at least a portion of the pressure-side protrusion 88 overlaps with the pressure-side cam portion 90. According to the above aspect, the rigidity of the pressure-side protrusion 88 is increased.

[0050] In the clutch device 10 of this embodiment, at least a portion of the pressure-side protruding portion 88 overlaps with the pressure-side slipper cam surface 90S when viewed in the axial direction of the output shaft 15. According to the above aspect, the rigidity of the pressure-side protruding portion 88 is increased.

[0051] In the clutch device 10 of this embodiment, the pressure-side protrusion 88 is located between the spring accommodating portion 84 and the pressure-side cam hole 73H in the circumferential direction S. According to the above aspect, the space between the spring accommodating portion 84 and the pressure-side cam hole 73H in the circumferential direction S can be effectively utilized, and the pressure-side protrusion 88 can be arranged compactly.

[0052] In the clutch device 10 of this embodiment, when viewed in the axial direction of the output shaft 15, the radial length LP1 of the pressure-side protrusion 88 is longer than the circumferential length LP2 of the pressure-side protrusion 88 in the circumferential direction S. According to the above aspect, the pressure-side protrusion 88 can be arranged compactly while increasing the contact area between the pressure-side protrusion 88 and the stopper plate 100.

[0053] In the clutch device 10 of this embodiment, the first contact surface 102 is formed to incline in the second direction D2 from the pressure-side assist cam surface 90A to the pressure-side slipper cam surface 90S. According to the above aspect, when changing from the clutch-off state to the clutch-on state, the component force F1 of the clutch spring 25 can prevent the pressure plate 70 from suddenly approaching the clutch center 40, and can also prevent the center-side assist cam surface 60A and the pressure-side assist cam surface 90A from suddenly contacting each other, causing the clutch to suddenly engage.

[0054] In the clutch device 10 of this embodiment, the distance in the circumferential direction S between the pressure-side protrusion 88 and the pressure-side slipper cam surface 90S is shorter than the distance in the circumferential direction S between the pressure-side protrusion 88 and the pressure-side assist cam surface 90A. According to the above aspect, the load applied from the pressure plate 70 to the stopper plate 100 is dispersed, and damage to the stopper plate 100 can be suppressed.

[0055] In the clutch device 10 of this embodiment, the surface 88D2 of the pressure-side protrusion 88 on the second direction D2 side is perpendicular to the axial direction of the output shaft 15. According to the above aspect, the load applied to the stopper plate 100 from the pressure plate 70 is mainly in the axial direction of the output shaft 15, and damage to the stopper plate 100 can be more reliably suppressed.

[0056] In the clutch device 10 of this embodiment, when viewed in the axial direction of the output shaft 15, a circle CL1 that is centered on the axis 15C of the output shaft 15 and passes through the center 84C of the spring accommodating portion 84 overlaps with the pressure-side protrusion 88. According to the above aspect, the pressure-side protrusion 88 can be arranged compactly.

[0057] Second Embodiment Figure 15 is a cross-sectional view showing an assembled state of a clutch center 40, a pressure plate 270, and a stopper plate 200 according to a second embodiment. As shown in Figure 15, the distance in the circumferential direction S between the pressure-side protrusion 88 and the pressure-side assist cam surface 90A is shorter than the distance in the circumferential direction S between the pressure-side protrusion 88 and the pressure-side slipper cam surface 90S. That is, the pressure-side protrusion 88 is positioned closer to the pressure-side assist cam surface 90A than the pressure-side slipper cam surface 90S. The pressure-side protrusion 88 is positioned closer to the second circumferential direction S2 than the pressure-side cam hole 73H. The pressure-side protrusion 88 is positioned closer to the first circumferential direction S1 than the spring accommodating portion 84. In this embodiment, the first contact surface 102 is formed so as to incline in the second direction D2 from the pressure-side slipper cam surface 90S to the pressure-side assist cam surface 90A.

[0058] As shown in Figure 15, end 25B in the second direction D2 is in contact with first contact surface 102 that slopes in second direction D2 from pressure-side slipper cam surface 90S to pressure-side assist cam surface 90A, so that a force is applied to pressure plate 270 in the direction of arrow F2 in Figure 15. As a result, during sudden acceleration, component force F2 of clutch spring 25 moves pressure-side assist cam surface 90A closer to center-side assist cam surface 60A, thereby reducing the feeling of free running. The same applies to the fourth embodiment, which will be described later.

[0059] In the clutch device 10 of this embodiment, the first contact surface 102 may be formed to incline in the second direction D2 from the pressure-side slipper cam surface 90S to the pressure-side assist cam surface 90A. According to the above aspect, during sudden acceleration, the component force F2 of the clutch spring 25 causes the pressure-side assist cam surface 90A to approach the center-side assist cam surface 60A, thereby reducing the feeling of free running. This configuration and effect are preferable for models that require good acceleration.

[0060] In the clutch device 10 of this embodiment, the distance in the circumferential direction S between the pressure-side protrusion 88 and the pressure-side assist cam surface 90A is shorter than the distance in the circumferential direction S between the pressure-side protrusion 88 and the pressure-side slipper cam surface 90S. According to the above aspect, the load applied from the pressure plate 270 to the stopper plate 200 is dispersed, and damage to the stopper plate 200 can be suppressed.

[0061] Third Embodiment Figure 16 is a cross-sectional view showing an assembled state of a clutch center 40, a pressure plate 370, and a stopper plate 300 according to a third embodiment. As shown in Figure 16, the stopper plate 300 includes a stopper-side protrusion 388. The stopper-side protrusion 388 is provided so as to be able to come into surface contact with the pressure plate 370. The stopper-side protrusion 388 is provided so as to be able to come into surface contact with a surface 70D2 of the pressure plate 370 on the second direction D2 side. When the pressure plate 370 contacts the stopper plate 300, the stopper-side protrusion 388 comes into contact with the pressure plate 370 first. The stopper-side protrusion 388 is provided on a surface 100D1 of the stopper plate 300 on the first direction D1 side. Here, the stopper-side protrusion 388 is provided on a portion of the surface 100D1 of the stopper plate 300 on the first direction D1 side, adjacent to the first contact surface 102. The stopper-side protrusion 388 is provided on the flat surface portion 103. The stopper-side protrusion 388 is located closer to the pressure-side cam hole 73H in the first circumferential direction S1. The stopper-side protrusion 388 is located closer to the spring accommodating portion 84 in the second circumferential direction S2. The stopper-side protrusion 388 is formed, for example, in a substantially rectangular shape. The stopper-side protrusion 388 may also be formed in a circular or elliptical shape. When viewed in the axial direction of the output shaft 15, for example, the radial length of the stopper-side protrusion 388 is longer than the length of the stopper-side protrusion 388 in the circumferential direction S. When viewed in the axial direction of the output shaft 15, a circle CL1 centered on the axis 15C of the output shaft 15 and passing through the center 84C of the spring accommodating portion 84 overlaps with the stopper-side protrusion 388. The distance in the circumferential direction S between the stopper-side protrusion 388 and the pressure-side slipper cam surface 90S is shorter than the distance in the circumferential direction S between the stopper-side protrusion 388 and the pressure-side assist cam surface 90A. That is, the stopper-side protrusion 388 is positioned closer to the pressure-side slipper cam surface 90S than the pressure-side assist cam surface 90A. When viewed in the axial direction of the output shaft 15, at least a portion of the stopper-side protrusion 388 overlaps with the pressure-side cam portion 90. When viewed in the axial direction of the output shaft 15, at least a portion of the stopper-side protrusion 388 overlaps with the pressure-side slipper cam surface 90S.The stopper-side protrusion 388 protrudes in the first direction D1. The stopper-side protrusion 388 protrudes from a surface 100D1 on the first direction D1 side toward the first direction D1. The surface 388D1 on the first direction D1 side of the stopper-side protrusion 388 is perpendicular to the axial direction of the output shaft 15. The surface 388D1 on the first direction D1 side is a flat surface. The surface 388D1 on the first direction D1 side is formed so as to be able to come into surface contact with the pressure plate 370. Note that the surface 388D1 on the first direction D1 side may be inclined with respect to the axial direction of the output shaft 15. Note that, unlike the pressure plate 70, the pressure plate 370 does not include a pressure-side protrusion 88.

[0062] According to the clutch device 10 of this embodiment, the first contact surface 102 of the stopper plate 300 is inclined in the circumferential direction S and contacts the end 25B of the clutch spring 25 in the second direction D2. This prevents the pressure plate 370 from suddenly approaching the clutch center 40. The clutch device 10 also includes a stopper-side protrusion 388 that can come into surface contact with the pressure plate 370. This allows the pressure plate 370 and the stopper plate 300 to come into surface contact via the stopper-side protrusion 388, dispersing the load applied from the pressure plate 370 to the stopper plate 300 and preventing damage to the stopper plate 300. Furthermore, since the stopper-side protrusion 388 is provided on the stopper plate 300, the weight of the pressure plate 370 can be reduced compared to when a protrusion is provided on the pressure plate 370, and the movement speed of the pressure plate 370 in the circumferential direction S and the axial direction can be improved.

[0063] In the clutch device 10 of this embodiment, the stopper-side protrusion 388 is provided on a portion of the surface 100D1 on the first direction D1 side of the stopper plate 300 that is adjacent to the first contact surface 102. According to the above-described aspect, damage to the stopper plate 300 can be more reliably suppressed.

[0064] In the clutch device 10 of this embodiment, the distance in the circumferential direction S between the stopper-side protrusion 388 and the pressure-side slipper cam surface 90S is shorter than the distance in the circumferential direction S between the stopper-side protrusion 388 and the pressure-side assist cam surface 90A. According to the above aspect, the load applied from the pressure plate 370 to the stopper plate 300 is dispersed, and damage to the stopper plate 300 can be suppressed.

[0065] In the clutch device 10 of this embodiment, the surface 388D1 of the stopper-side protrusion 388 on the first direction D1 side is perpendicular to the axial direction of the output shaft 15. According to the above-described aspect, the load applied to the stopper plate 300 from the pressure plate 370 is mainly in the axial direction of the output shaft, and damage to the stopper plate 300 can be more reliably suppressed.

[0066] In the clutch device 10 of this embodiment, when viewed in the axial direction of the output shaft 15, a circle CL1 that is centered on the axis of the output shaft 15 and passes through the center 84C of the spring accommodating portion 84 overlaps with the stopper-side protrusion 388. According to the above aspect, the stopper-side protrusion 388 can be arranged compactly.

[0067] <Fourth Embodiment> Figure 17 is a cross-sectional view showing the assembled state of the clutch center 40, pressure plate 370, and stopper plate 400 according to the fourth embodiment. As shown in Figure 17, the distance in the circumferential direction S between the stopper-side protrusion 388 and the pressure-side assist cam surface 90A is shorter than the distance in the circumferential direction S between the stopper-side protrusion 388 and the pressure-side slipper cam surface 90S. That is, the stopper-side protrusion 388 is positioned closer to the pressure-side assist cam surface 90A than the pressure-side slipper cam surface 90S. The stopper-side protrusion 388 is positioned closer to the second circumferential direction S2 than the pressure-side cam hole 73H. The stopper-side protrusion 388 is positioned closer to the first circumferential direction S1 than the spring accommodating portion 84.

[0068] In the clutch device 10 of this embodiment, the distance in the circumferential direction S between the stopper-side protrusion 388 and the pressure-side assist cam surface 90A is shorter than the distance in the circumferential direction S between the stopper-side protrusion 388 and the pressure-side slipper cam surface 90S. According to the above aspect, the load applied from the pressure plate 370 to the stopper plate 400 is dispersed, and damage to the stopper plate 400 can be suppressed.

[0069] 18 is a cross-sectional view showing an assembled state of a clutch center 540, a pressure plate 570, and a stopper plate 500 according to a fifth embodiment. The clutch device 10 according to the fifth embodiment is a so-called external disconnection type clutch device.

[0070] As shown in Figure 18, the clutch center 540 is located closer to the first direction D1 than the pressure plate 570. The clutch center 540 is located between the pressure plate 570 and the stopper plate 500 in the direction D. The clutch center 540 has a spring accommodating portion 584. The spring accommodating portion 584 is formed in the center-side cam portion 60. The spring accommodating portion 584 is formed so as to be recessed from the first direction D1 toward the second direction D2. The spring accommodating portion 584 is an example of an accommodating portion.

[0071] As shown in FIG. 18 , the clutch center 540 has a center-side protrusion 548. The center-side protrusion 548 is provided so as to be able to come into surface contact with the stopper plate 500. The center-side protrusion 548 is provided so as to be able to come into surface contact with the second contact surface 504 of the stopper plate 500. The center-side protrusion 548 is provided on a surface 540D1 on the first direction D1 side of the clutch center 540. Here, the center-side protrusion 548 is provided on a portion of the surface 540D1 on the first direction D1 side of the clutch center 540 that is adjacent to the spring accommodating portion 584. The center-side protrusion 548 is located between the spring accommodating portion 584 and the center-side cam hole 43H in the circumferential direction S. The center-side protrusion 548 is located closer to the second circumferential direction S2 than the center-side cam hole 43H. The center-side protrusion 548 is located closer to the first circumferential direction S1 than the spring accommodating portion 584. The center-side protrusion 548 is located radially outward than the output shaft holding portion 50. The center-side protrusion 548 is located radially inward than the flange 68. The position and shape of the center-side protrusion 548 are similar to those of the pressure-side protrusion 88. The distance in the circumferential direction S between the center-side protrusion 548 and the center-side slipper cam surface 60S is shorter than the distance in the circumferential direction S between the center-side protrusion 548 and the center-side assist cam surface 60A. In other words, the center-side protrusion 548 is located closer to the center-side slipper cam surface 60S than the center-side assist cam surface 60A. When viewed in the axial direction of the output shaft 15, at least a portion of the center-side protrusion 548 overlaps with the center-side cam portion 60. When viewed in the axial direction of the output shaft 15, at least a portion of the center-side protrusion 548 overlaps with the center-side slipper cam surface 60S. The center-side protrusion 548 protrudes in the first direction D1. The center-side protrusion 548 protrudes in the first direction D1 from the surface 540D1 on the first direction D1 side. The surface 548D1 on the first direction D1 side of the center-side protrusion 548 is perpendicular to the axial direction of the output shaft 15. The surface 548D1 on the first direction D1 side is a flat surface. The surface 548D1 on the first direction D1 side is formed to be able to come into surface contact with the stopper plate 500. Note that the surface 548D1 on the first direction D1 side may be inclined with respect to the axial direction of the output shaft 15.

[0072] 18 , the pressure plate 570 has a boss portion 554. The boss portion 554 extends toward the clutch center 540 (i.e., toward the first direction D1). The boss portion 554 is provided on the pressure-side cam portion 90. The boss portion 554 is located between the pressure-side assist cam surface 90A and the pressure-side slipper cam surface 90S in terms of the rotational direction S.

[0073] 18 , the end 25A of the clutch spring 25 in the first direction D1 contacts the stopper plate 100. More specifically, the end 25A in the first direction D1 contacts the first contact surface 502 of the stopper plate 100. The end 25B of the clutch spring 25 in the second direction D2 contacts the clutch center 540. More specifically, the end 25B in the second direction D2 contacts the retaining surface 84A of the spring accommodating portion 584.

[0074] As shown in Figure 18, the stopper plate 500 is located closer to the first direction D1 than the clutch center 540. The stopper plate 500 is provided so as to be able to come into contact with the clutch center 540. The stopper plate 500 is a member that prevents the pressure plate 570 from moving away from the clutch center 540 in the second direction D2 by more than a predetermined distance. The stopper plate 500 is fixed to the pressure plate 570. The stopper plate 500 is fixed to the boss portion 554 of the pressure plate 570 by the bolt 28. The stopper plate 500 is fixed by tightening it to the boss portion 554 of the pressure plate 570 via the bolt 28 with the clutch spring 25 accommodated in the spring accommodating portion 584.

[0075] As shown in FIG. 18 , the stopper plate 500 includes an inclined portion 501 and a flat portion 503. The inclined portions 501 and the flat portions 503 are alternately arranged in the circumferential direction S. In this embodiment, three inclined portions 501 and three flat portions 503 are alternately arranged in succession. The inclined portion 501 has a first contact surface 502 provided on a surface 500D2 on the second direction D2 side of the stopper plate 500. The first contact surface 502 is an example of a contact surface. The first contact surface 502 is inclined in the circumferential direction S. The first contact surface 502 is formed so as to incline in the first direction D1 from the center-side assist cam surface 60A to the center-side slipper cam surface 60S. The first contact surface 502 contacts the end 25A of the clutch spring 25 in the first direction D1. The flat surface 503 has a second contact surface 504 provided on a surface 500D2 on the second direction D2 side of the stopper plate 500. The second contact surface 504 is perpendicular to the axial direction of the output shaft 15. The second contact surface 504 is provided to be able to come into surface contact with the center-side protrusion 548 of the clutch center 540. In this way, when the pressure plate moves in the second direction D2 and the stopper plate 500 and the clutch center 540 come into contact, the center-side protrusion 548 of the clutch center 540 comes into surface contact with the second contact surface 504 of the stopper plate 500, so that the load applied from the clutch center 540 to the stopper plate 500 is dispersed.

[0076] As described above, according to the clutch device 10 of this embodiment, the first contact surface 502 of the stopper plate 500 is inclined in the circumferential direction S and contacts the end 25A of the clutch spring 25 in the first direction D1. This makes it possible to prevent the pressure plate 570 from suddenly approaching the clutch center 540 and reduce the feeling of free running during sudden acceleration. The clutch device 10 also includes a center-side protrusion 548 that can come into surface contact with the stopper plate 500. As a result, the clutch center 540 and the stopper plate 500 come into surface contact via the center-side protrusion 548, which distributes the load applied from the clutch center 540 to the stopper plate 500 and prevents damage to the stopper plate 500.

[0077] The clutch device 10 of this embodiment includes the center-side protrusion 548. According to the above aspect, the pressure plate 570 is prevented from suddenly approaching the clutch center 540, and damage to the stopper plate 500 can be suppressed.

[0078] In the clutch device 10 of this embodiment, the center-side protrusion 548 is provided on a portion of the surface 540D1 on the first direction D1 side of the clutch center 540 that is adjacent to the spring accommodating portion 584. According to the above-described aspect, damage to the stopper plate 500 can be more reliably suppressed.

[0079] Sixth Embodiment FIG. 19 is a cross-sectional view showing an assembled state of a clutch center 640, a pressure plate 570, and a stopper plate 600 according to a sixth embodiment. As shown in FIG. 19 , the stopper plate 600 includes a stopper-side protrusion 688. The stopper-side protrusion 688 is provided to be capable of surface contact with the clutch center 640. The stopper-side protrusion 688 is provided to be capable of surface contact with a surface 540D1 of the clutch center 640 on the first direction D1 side. The stopper-side protrusion 688 is provided on a surface 500D2 of the stopper plate 600 on the second direction D2 side. Here, the stopper-side protrusion 688 is provided on a portion of the surface 500D2 of the stopper plate 600 on the second direction D2 side, adjacent to the first contact surface 502. The stopper-side protrusion 688 is provided on the flat surface portion 503. The stopper-side protrusion 688 is formed, for example, in a substantially rectangular shape. The stopper-side protrusion 688 may be formed in a circular or elliptical shape. When viewed in the axial direction of the output shaft 15, for example, the radial length of the stopper-side protrusion 688 is longer than the length of the stopper-side protrusion 688 in the circumferential direction S. When viewed in the axial direction of the output shaft 15, a circle CL1 centered on the axis 15C of the output shaft 15 and passing through the center 84C of the spring accommodating portion 584 overlaps with the stopper-side protrusion 688. The distance in the circumferential direction S between the stopper-side protrusion 688 and the center-side slipper cam surface 60S is shorter than the distance in the circumferential direction S between the stopper-side protrusion 688 and the center-side assist cam surface 60A. In other words, the stopper-side protrusion 688 is located closer to the center-side slipper cam surface 60S than the center-side assist cam surface 60A. When viewed in the axial direction of the output shaft 15, at least a portion of the stopper-side protrusion 688 overlaps with the center-side cam portion 60. When viewed from the axial direction of the output shaft 15, at least a portion of the stopper-side protrusion 688 overlaps with the center-side slipper cam surface 60S. The stopper-side protrusion 688 protrudes in the second direction D2. The stopper-side protrusion 688 protrudes in the second direction D2 from the surface 500D2 on the second direction D2 side. The surface 688D2 on the second direction D2 side of the stopper-side protrusion 688 is perpendicular to the axial direction of the output shaft 15. The surface 688D2 on the second direction D2 side is a flat surface. The surface 688D2 on the second direction D2 side is formed to be able to come into surface contact with the clutch center 640.The surface 388D1 on the first direction D1 side may be inclined with respect to the axial direction of the output shaft 15. Unlike the clutch center 540, the clutch center 640 does not include a center-side protrusion 548.

[0080] As described above, according to the clutch device 10 of this embodiment, the first contact surface 502 of the stopper plate 600 is inclined in the circumferential direction S and contacts the end 25A of the clutch spring 25 in the first direction D1. This makes it possible to prevent the pressure plate 570 from suddenly approaching the clutch center 540. The clutch device 10 also includes a stopper-side protrusion 688 that can come into surface contact with the clutch center 540. As a result, the clutch center 540 and the stopper plate 600 come into surface contact via the stopper-side protrusion 688, so that the load applied from the clutch center 540 to the stopper plate 600 is dispersed, making it possible to prevent damage to the stopper plate 600.

[0081] The clutch device 10 of this embodiment includes the stopper-side protrusion 688. According to the above aspect, it is possible to prevent the pressure plate 570 from suddenly approaching the clutch center 540 and also to prevent damage to the stopper plate 600.

[0082] In the clutch device 10 of this embodiment, the stopper-side protrusion 688 is provided on a portion of the surface 500D2 on the second direction D2 side of the stopper plate 600 that is adjacent to the first contact surface 502. According to the above-described aspect, damage to the stopper plate 600 can be more reliably suppressed.

[0083] Although the preferred embodiments of the present invention have been described above, the above-described embodiments are merely examples, and the present invention can be embodied in various other forms.

[0084] In the first and second embodiments described above, the pressure-side protrusion 88 is adjacent to a portion of the first contact surface 102 that is farthest from the pressure-side protrusion 88 in the direction D. However, for example, the pressure-side protrusion 88 may be adjacent to a portion of the first contact surface 102 that is closest to the pressure-side protrusion 88 in the direction D. For example, as shown in FIG. 13 , the pressure-side protrusion 88 may be located closer to the spring accommodating portion 84 in the first circumferential direction S1.

[0085] In the third and fourth embodiments described above, the stopper-side protrusion 388 is adjacent to a portion of the first contact surface 102 that is farthest from the first contact surface 102 in the direction D. However, for example, the stopper-side protrusion 388 may be adjacent to a portion of the first contact surface 102 that is closest to the first contact surface 102 in the direction D. For example, as shown in Fig. 16 , the stopper-side protrusion 388 may be located closer to the spring accommodating portion 84 in the first circumferential direction S1.

[0086] In the fifth embodiment described above, the center-side protrusion 548 is adjacent to the portion of the first contact surface 502 that is farthest from it in the direction D. However, for example, it may be adjacent to the portion of the first contact surface 502 that is closest to it in the direction D. For example, as shown in FIG. 18 , the center-side protrusion 548 may be located closer to the spring accommodating portion 584 in the second circumferential direction S2.

[0087] In the sixth embodiment described above, the stopper-side protrusion 688 is adjacent to a portion of the first contact surface 502 that is farthest from the first contact surface 502 in the direction D. However, for example, the stopper-side protrusion 688 may be adjacent to a portion of the first contact surface 502 that is closest to the first contact surface 502 in the direction D. For example, as shown in Fig. 19 , the stopper-side protrusion 688 may be located closer to the spring accommodating portion 584 in the second circumferential direction S2.

[0088] In the fifth and sixth embodiments described above, the first contact surface 502 is formed so as to incline in the first direction D1 as it moves from the center-side assist cam surface 60A to the center-side slipper cam surface 60S, but this is not limiting. For example, the first contact surface 502 may be formed so as to incline in the first direction D1 as it moves from the center-side slipper cam surface 60S to the center-side assist cam surface 60A. In this case, the center-side protrusion 548 and the stopper-side protrusion 688 may be located closer to the center-side assist cam surface 60A (e.g., closer to the second circumferential direction S2 than the spring accommodating portion 584).

[0089] In each of the above-described embodiments, a portion of the output side rotating plate 22 is held by spline engagement with the center side fitting teeth 47 and spline grooves 48 of the clutch center 40, and another portion of the output side rotating plate 22 is held by the pressure side fitting teeth 77 of the pressure plate 70, but this is not limiting. For example, the pressure side fitting teeth 77 may be configured to hold all of the output side rotating plate 22. In this case, for example, the clutch center 40 does not include a member equivalent to the center side fitting teeth 47.

[0090] REFERENCE SIGNS LIST 10 Clutch device 15 Output shaft 20 Input side rotating plate 22 Output side rotating plate 25 Clutch spring 25A End in first direction 25B End in second direction 30 Clutch housing 40 Clutch center 60 Center side cam portion 60A Center side assist cam surface 60S Center side slipper cam surface 70 Pressure plate 73H Pressure side cam hole (through hole) 84 Spring accommodating portion (accommodating portion) 88 Pressure side protrusion 90 Pressure side cam portion 90A Pressure side assist cam surface 90S Pressure side slipper cam surface 100 Stopper plate 102 First contact surface (contact surface) 104 Second contact surface

Claims

1. A clutch device which transmits or cuts off the rotational driving force of an input shaft to an output shaft, comprising: a clutch center housed in a clutch housing which holds a plurality of input side rotating plates which are rotationally driven by the rotational drive of the input shaft and which is rotationally driven together with the output shaft; a pressure plate which is arranged to be able to approach or move away from the clutch center and to be rotatable relative to the clutch center, which holds a plurality of output side rotating plates which are arranged alternately with the input side rotating plates and which is capable of pressing the input side rotating plates and the output side rotating plates; a clutch spring which urges the pressure plate in a first direction, when a direction in which the pressure plate approaches the clutch center is defined as a first direction and a direction in which the pressure plate moves away from the clutch center is defined as a second direction; and a stopper plate which is fixed to the clutch center and arranged to be able to come into contact with the pressure plate, and which prevents the pressure plate from moving away from the clutch center in the second direction by more than a predetermined distance. a clutch device in which an end of the clutch spring in the first direction contacts the pressure plate and an end of the clutch spring in the second direction contacts the stopper plate, the pressure plate having a accommodating portion recessed from the second direction towards the first direction and accommodating the clutch spring, the stopper plate having a contact surface provided on a surface on the first direction side and inclined circumferentially and contacting the end of the clutch spring in the second direction, and a stopper side protrusion provided on the first direction side surface of the stopper plate, protruding in the first direction and capable of surface contact with the pressure plate, or a pressure side protrusion provided on the second direction side surface of the pressure plate, protruding in the second direction and capable of surface contact with the stopper plate.

2. A clutch device according to claim 1, further comprising the pressure side protrusion.

3. The clutch device according to claim 2, wherein the pressure side protrusion is provided on a portion of the surface of the pressure plate facing the second direction, the portion being adjacent to the housing portion.

4. A clutch device as described in claim 2 or 3, wherein the pressure plate is provided with a plurality of pressure side cam portions having a pressure side assist cam surface which generates a force in a direction from the pressure plate towards the clutch center in order to increase 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 a pressure side slipper cam surface which separates the pressure plate from the clutch center in order to reduce the pressing force between the input side rotating plate and the output side rotating plate, and at least a portion of the pressure side protrusion overlaps with the pressure side cam portion when viewed in the axial direction of the output shaft.

5. The clutch device according to claim 4, wherein at least a portion of said pressure-side protrusion overlaps with said pressure-side slipper cam surface when viewed in the axial direction of said output shaft.

6. A clutch device as set forth in claim 2 or 3, wherein the pressure plate has a through hole penetrating in the axial direction of the output shaft, and the pressure side protrusion is located between the accommodation portion and the through hole in the circumferential direction.

7. The clutch device according to claim 6, wherein, when viewed in the axial direction of the output shaft, the radial length of the pressure side protrusion is longer than the circumferential length of the pressure side protrusion.

8. A clutch device according to claim 1, further comprising the stopper side protrusion.

9. The clutch device according to claim 8, wherein said stopper-side projection is provided on a portion of said surface of said stopper plate on said first direction side, said portion being adjacent to said contact surface.

10. A clutch device as described in claim 1, wherein the pressure plate comprises a plurality of pressure side cam portions having a pressure side assist cam surface which generates a force in a direction from the pressure plate towards the clutch center in order to increase 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 a pressure side slipper cam surface which separates the pressure plate from the clutch center in order to reduce the pressing force between the input side rotating plate and the output side rotating plate, the accommodating portion is formed in the pressure side cam portion, and the contact surface is formed so as to incline in the second direction as it goes from the pressure side slipper cam surface to the pressure side assist cam surface.

11. A clutch device as described in claim 10, wherein the circumferential distance between the stopper side protrusion or the pressure side protrusion and the pressure side assist cam surface is shorter than the circumferential distance between the stopper side protrusion or the pressure side protrusion and the pressure side slipper cam surface.

12. A clutch device as described in claim 1, wherein the pressure plate comprises a plurality of pressure side cam portions having a pressure side assist cam surface which generates a force in a direction from the pressure plate towards the clutch center in order to increase 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 a pressure side slipper cam surface which separates the pressure plate from the clutch center in order to reduce the pressing force between the input side rotating plate and the output side rotating plate, the accommodating portion is formed in the pressure side cam portion, and the contact surface is formed so as to incline in the second direction as it goes from the pressure side assist cam surface to the pressure side slipper cam surface.

13. A clutch device as described in claim 12, wherein the circumferential distance between the stopper side protrusion or the pressure side protrusion and the pressure side slipper cam surface is shorter than the circumferential distance between the stopper side protrusion or the pressure side protrusion and the pressure side assist cam surface.

14. A clutch device as described in claim 1, wherein, when the pressure side protrusion is provided, the second direction side surface of the pressure side protrusion is perpendicular to the axial direction of the output shaft, and when the stopper side protrusion is provided, the first direction side surface of the stopper side protrusion is perpendicular to the axial direction of the output shaft.

15. A clutch device as set forth in claim 1, wherein, when viewed in the axial direction of the output shaft, a circle centered on the axis of the output shaft and passing through the center of the accommodating portion overlaps with the pressure side protrusion or the stopper side protrusion.

16. A clutch device for transmitting or interrupting the rotational driving force of an input shaft to an output shaft, comprising: a clutch center accommodated in a clutch housing holding a plurality of input side rotating plates which are rotationally driven by the rotational drive of the input shaft and which is rotationally driven together with the output shaft; a pressure plate which is arranged to be able to approach or move away from the clutch center and to be rotatable relative to the clutch center, holds a plurality of output side rotating plates arranged alternately with the input side rotating plates, and is capable of pressing the input side rotating plates and the output side rotating plates; a clutch spring which urges the pressure plate in a first direction, when a direction in which the pressure plate approaches the clutch center is defined as a first direction and a direction in which the pressure plate moves away from the clutch center is defined as a second direction; and a stopper plate which is fixed to the pressure plate, is arranged to be able to come into contact with the clutch center, and prevents the pressure plate from moving away from the clutch center in the second direction by more than a predetermined distance, a clutch device in which an end of the clutch spring in the first direction contacts the stopper plate and an end of the clutch spring in the second direction contacts the clutch center, the clutch center having a accommodating portion recessed from the first direction toward the second direction and accommodating the clutch spring, the stopper plate having a contact surface provided on a surface on the second direction side, inclined circumferentially, and contacting the end of the clutch spring in the first direction, and a stopper side protrusion provided on the surface on the second direction side of the stopper plate, protruding in the second direction and capable of surface contact with the clutch center, or a center side protrusion provided on the surface on the first direction side of the clutch center, protruding in the first direction, and capable of surface contact with the stopper plate.

17. A clutch device as set forth in claim 16, further comprising the center side protrusion.

18. A clutch device according to claim 17, wherein the center-side protrusion is provided on a portion of the face of the clutch center on the first direction side that is adjacent to the housing portion.

19. The clutch device according to claim 16, further comprising the stopper side protrusion.

20. A clutch device according to claim 19, wherein the stopper-side protrusion is provided on a portion of the surface of the stopper plate facing the second direction, the portion being adjacent to the contact surface.

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