JP7481420B2 - Clutch device - Google Patents

Description

The present invention relates to a clutch device. More specifically, the present invention relates to a clutch device that selectively transmits or cuts off the rotational driving force of an input shaft, which is driven by a prime mover such as an engine, to an output shaft.

Traditionally, vehicles such as motorcycles have been equipped with clutch devices. The clutch device is disposed between the engine and the drive wheels, and transmits or blocks the rotational driving force of the engine to the drive wheels. The clutch device usually comprises a number of input side rotating plates that rotate due to the rotational driving force of the engine, and a number of output side rotating plates connected to an output shaft that transmits the rotational driving force to the drive wheels. The input side rotating plates and the output side rotating plates are arranged alternately in the stacking direction, and the transmission or blocking of the rotational driving force is performed by pressing the input side rotating plates and the output side rotating plates together and separating them.

For example, Patent Document 1 discloses a clutch device that includes a clutch center that holds an output rotating plate, and a pressure plate that is arranged so that it can move toward and away from the clutch center. The pressure plate is configured so that it can press against the input rotating plate and the output rotating plate. In this way, the clutch center and pressure plate are assembled together and used in the clutch device.

The clutch center and pressure plate of the clutch device in Patent Document 1 are equipped with an assist cam surface that generates a force in a direction that moves the pressure plate closer to the clutch center when the rotational drive force of the engine can be transmitted to the output shaft, thereby increasing the pressing force between the input side rotating plate and the output side rotating plate, and a slipper cam surface that moves the pressure plate away from the clutch center when the rotational speed of the clutch center exceeds the rotational speed of the pressure plate, thereby reducing the pressing force between the input side rotating plate and the output side rotating plate.

Patent No. 5847551

However, depending on the positions of the assist cam surface and slipper cam surface of the clutch center and the assist cam surface and slipper cam surface of the pressure plate, the cam surfaces of the two may interfere with each other when assembling the clutch center and pressure plate, making assembly difficult.

The present invention was made in consideration of these points, and its purpose is to provide a clutch device that is easy to assemble between the clutch center and the pressure plate.

The clutch device according to the present invention is a clutch device that transmits or interrupts 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, holds a plurality of output side rotating plates that are arranged alternately with the input side rotating plates, and is rotationally driven together with the output shaft, and a pressure plate that is arranged to be able to approach or move away from the clutch center and to rotate relatively thereto, and is able to press the input side rotating plates and the output side rotating plates, and the clutch center is located radially outward of the output shaft holding portion to which the output shaft is connected, and when the clutch center rotates relative to the pressure plate, a center-side assist cam surface that generates a force in a direction that brings the pressure plate closer to the clutch center in order to increase the pressing force between the input side rotating plate and the output side rotating plate, a center-side slipper cam surface that moves the pressure plate away from the clutch center in order to reduce the pressing force between the input side rotating plate and the output side rotating plate, and a center-side top surface that is located between the center-side assist cam surface and the center-side slipper cam surface, and the pressure plate is configured to be able to come into contact with the center-side assist cam surface when rotating relative to the clutch center, and to generate a force in a direction that brings the pressure plate closer to the clutch center in order to increase the pressing force between the input side rotating plate and the output side rotating plate. a pressure-side assist cam surface that generates a force in a direction that moves the pressure plate closer to the clutch center, a pressure-side slipper cam surface that is configured to be able to come into contact with the center-side slipper cam surface and that moves the pressure plate away from the clutch center to reduce the pressing force between the input-side rotating plate and the output-side rotating plate, and a pressure-side top surface that is located between the pressure-side assist cam surface and the pressure-side slipper cam surface; and a plurality of pressure-side cam portions having a movement direction, a direction in which the pressure plate approaches and moves away from the clutch center, a first direction, a second direction, a third direction, and a fourth direction, respectively. When the direction in which the assist plate moves away from the clutch center is defined as a second direction, and the direction from one of the pressure side cam portions to the other of the pressure side cam portions in the circumferential direction is defined as a first circumferential direction, and the direction from the other of the pressure side cam portions to one of the pressure side cam portions is defined as a second circumferential direction, the center side top surface and the pressure side top surface are located at the same position in the moving direction, and the end of the center side assist cam surface in the second direction faces the end of the pressure side assist cam surface in the first direction, the end of the pressure side slipper cam surface in the first direction is located on the first circumferential side of the end of the center side slipper cam surface in the second direction.

According to the clutch device of the present invention, when the center side top surface and the pressure side top surface are located at the same position in the moving direction and the end of the center side assist cam surface in the second direction faces the end of the pressure side assist cam surface in the first direction, the end of the pressure side slipper cam surface in the first direction is located on the first circumferential side of the end of the center side slipper cam surface in the second direction. According to the above aspect, when the pressure plate is assembled to the clutch center, the end of the center side assist cam surface in the second direction and the end of the pressure side assist cam surface in the first direction do not interfere with each other, and the pressure plate can be moved in the first direction relative to the clutch center along the center side slipper cam surface, so that the pressure plate can be easily assembled to the clutch center.

Another 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, holds a plurality of output side rotating plates that are arranged alternately with the input side rotating plates, and is rotationally driven together with the output shaft, and a pressure plate that is provided so as to be able to approach or move away from the clutch center and to rotate relatively thereto, and can press the input side rotating plates and the output side rotating plates. The clutch center includes an output shaft holding portion to which the output shaft is connected, a center side assist cam surface that is located radially outward of the output shaft holding portion and that, when rotated relative to the pressure plate, generates a force in a direction that brings the pressure plate closer to the clutch center in order to increase the pressing force between the input side rotating plate and the output side rotating plate, and a pressure plate that is provided so as to be able to press the input side rotating plate and the output side rotating plate in order to increase the pressing force between the input side rotating plate and the output side rotating plate. and a boss portion located radially outward from the output shaft holding portion and extending toward the pressure plate, and the pressure plate has a pressure-side assist cam surface configured to be capable of contacting the center-side assist cam surface when rotating relative to the clutch center, and a pressure-side slipper cam surface configured to be capable of contacting the center-side slipper cam surface and to generate a force in a direction that brings the pressure plate closer to the clutch center in order to increase the pressing force between the input side rotating plate and the output side rotating plate, and a pressure-side slipper cam surface configured to be capable of contacting the center-side slipper cam surface and to move the pressure plate away from the clutch center in order to reduce the pressing force between the input side rotating plate and the output side rotating plate, and a plurality of pressure-side cam portions having pressure-side top surfaces located between the cam surfaces, and a pressure-side top surface located between the cam surfaces, wherein a direction in which the pressure plate approaches and moves away from the clutch center is defined as a movement direction, 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 direction in a circumferential direction from one of the pressure-side cam portions to the other of the pressure-side cam portions is defined as a first circumferential direction, and a direction from the other of the pressure-side cam portions to one of the pressure-side cam portions is defined as a second circumferential direction, the pressure plate is formed in the pressure-side cam portion so as to be recessed from the second direction to the first direction, and is provided with a spring accommodating portion that accommodates a pressure spring that urges the pressure plate in the first direction, and a ring-shaped spring seat accommodated in the spring accommodating portion, an insertion hole is formed through the spring accommodating portion, and the boss portion is configured to be configured to engage with the insertion hole. In a cross-sectional view taken along a plane passing through the boss portion and extending in the circumferential direction and the axial direction of the output shaft, when the center side top surface and the pressure side top surface are positioned at the same position in the moving direction, the total length of the first length, which is the circumferential distance between the end of the center side assist cam surface in the second direction and the end of the pressure side assist cam surface in the first direction, and the second length, which is the circumferential distance between the end of the center side slipper cam surface in the second direction and the end of the pressure side slipper cam surface in the first direction, is longer than the third length, which is the circumferential distance between the first inner edge and the second inner edge when the spring seat is located at the furthest position on the second circumferential side in the spring accommodating portion, the first inner edge, which is the inner edge of the spring seat on the first circumferential side, contacts the boss portion, and the second inner edge, which is the inner edge of the insertion hole on the first circumferential side, does not contact the boss portion.

According to another clutch device of the present invention, in a cross-sectional view taken along a plane passing through the axis of the boss and extending in the circumferential direction and in the axial direction of the output shaft, when the center-side top surface and the pressure-side top surface are located at the same position in the moving direction, the total length of the first length, which is the circumferential distance between the end of the center-side assist cam surface in the second direction and the end of the pressure-side assist cam surface in the first direction, and the second length, which is the circumferential distance between the end of the center-side slipper cam surface in the second direction and the end of the pressure-side slipper cam surface in the first direction, is longer than the third length, which is the circumferential distance between the first inner edge and the second inner edge when the spring seat is located at the second circumferential side of the spring seat in the spring accommodating section, the first inner edge, which is the inner edge of the first circumferential side of the spring seat, contacts the boss, and the second inner edge, which is the inner edge of the first circumferential side of the insertion hole, does not contact the boss. According to the above aspect, even when the spring seat is accommodated in the spring accommodating section, the pressure plate and the clutch center can be easily assembled. For example, if the total length is shorter than the third length, when attempting to assemble the pressure plate to the clutch center with the spring seat housed in the spring housing portion, the end of the center side assist cam surface in the second direction and the end of the pressure side assist cam surface in the first direction will interfere with each other, so the spring seat must be housed in the spring housing portion after the pressure plate is assembled to the clutch center, making the assembly process cumbersome.

The present invention provides a clutch device that is easy to assemble between the clutch center and the pressure plate.

FIG. 1 is a cross-sectional view of a clutch device according to one embodiment. FIG. 2 is a perspective view of a clutch center according to one embodiment. FIG. 3 is a plan view of the clutch center according to one embodiment. FIG. 4 is a perspective view of a pressure plate according to one embodiment. FIG. 5 is a plan view of a pressure plate according to one embodiment. FIG. 6 is a perspective view of a pressure plate according to one embodiment. FIG. 7 is a plan view of a pressure plate according to one embodiment. FIG. 8 is an enlarged side view of a portion of the pressure-side cam portion according to one embodiment. FIG. 9 is an enlarged perspective view of a portion of a pressure plate according to an embodiment. FIG. 10 is a plan view showing a state in which the clutch center and the pressure plate according to one embodiment are combined. FIG. 11A is a schematic diagram for explaining the action of the center side assist cam surface and the pressure side assist cam surface. FIG. 11B is a schematic diagram for explaining the action of the center-side slipper cam surface and the pressure-side slipper cam surface. FIG. 12 is an enlarged cross-sectional view of a portion of the pressure plate and the clutch center according to one embodiment. FIG. 13 is an enlarged cross-sectional view of a portion of a pressure plate and a clutch center according to another embodiment.

Below, an embodiment of the clutch device according to the present invention will be described with reference to the drawings. Note that the embodiment described here is, of course, not intended to limit the present invention in any particular way. In addition, the same reference numerals are used for components and parts that perform the same function, and duplicate descriptions will be omitted or simplified as appropriate.

Figure 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 an engine of a 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.

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 (an example of a moving direction), 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. The circumferential direction of the clutch center 40 and the pressure plate 70 is referred to as the circumferential direction S, the direction from one pressure side cam portion 90 to the other pressure side cam portion 90 in the circumferential direction S is referred to as the 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 the 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, and the axial direction of the pressure plate 70 are the same as the direction D. Additionally, the pressure plate 70 and the clutch center 40 rotate in a first circumferential direction S1. However, the above direction is merely determined for the convenience of explanation, and does not limit the installation mode of the clutch device 10 or the present invention in any way.

As shown in FIG. 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, and a stopper plate 100.

As shown in FIG. 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. In other words, 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.

As shown in FIG. 1, the output shaft 15 is provided 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 a flow passage for clutch oil. The clutch oil flows inside the output shaft 15, i.e., inside the hollow portion 15H. The push rod 16A and the push member 16B are provided so as to be slidable inside the hollow portion 15H of the output shaft 15. One end (the end on the left side in the figure) of the push rod 16A is connected to a clutch operation lever (not shown) of the motorcycle, and slides inside the hollow portion 15H by operating the clutch operation lever to press the push member 16B in the second direction D2. A part of the push member 16B protrudes outward from the output shaft 15 (here, 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 be smaller than the inner diameter of the hollow portion 15H, ensuring the flow of clutch oil within the hollow portion 15H.

The clutch housing 30 is made of an aluminum alloy. The clutch housing 30 is formed in 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 from an edge of the bottom wall 31 in the second direction D2. The clutch housing 30 holds a plurality of input side rotating plates 20.

As shown in FIG. 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 due to the rotational drive of the input shaft of the engine. The input gear 35 rotates integrally with the clutch housing 30 independently of the output shaft 15.

The input side rotating plate 20 is rotated 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. The input side rotating plate 20 is provided so as to be rotatable integrally with the clutch housing 30.

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 a flat plate formed into an annular shape. The input side rotating plate 20 is formed by punching a thin plate made of SPCC (cold rolled steel plate) material into an annular shape. 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 μm to several tens of μm deep are formed between the friction materials to hold clutch oil.

As shown in FIG. 1, the clutch center 40 is housed in the clutch housing 30. The clutch center 40 is arranged concentrically with the clutch housing 30. The clutch center 40 has a cylindrical body 42 and a flange 68 extending radially outward from the outer periphery of the 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 the direction D. The clutch center 40 is driven to rotate together with the output shaft 15.

As shown in FIG. 2, the main body 42 includes an annular base wall 43, an outer peripheral wall 45 located radially outward from the base wall 43 and extending in the second direction D2, an output shaft holder 50 provided in the center of the base wall 43, a plurality of center side cam portions 60 connected to the base wall 43 and the outer peripheral wall 45, and a center side fitting portion 58.

The output shaft holding portion 50 is formed in a cylindrical shape. The output shaft holding portion 50 has an insertion hole 51 into which the output shaft 15 is inserted and spline-fitted. The insertion hole 51 is formed through the base wall 43. The 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.

As shown in FIG. 2, the outer peripheral wall 45 of the clutch center 40 is disposed radially outward from 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, 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, and an oil discharge hole 49. The center side fitting teeth 47 hold the output side rotating plate 22. The center side fitting teeth 47 are arranged 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 oil discharge holes 49 are formed penetrating the outer peripheral wall 45 in the radial direction. The oil discharge holes 49 are formed between the adjacent center side fitting teeth 47. That is, the oil discharge holes 49 are formed in the spline grooves 48. The oil discharge holes 49 are formed on the side of the center side cam portion 60. The oil discharge holes 49 are formed on the side of the center side slipper cam surface 60S of the center side cam portion 60. The oil discharge holes 49 are formed on the second circumferential direction S2 side of the center side slipper cam surface 60S. The oil discharge holes 49 are formed on the first circumferential direction S1 side of the boss portion 54 described later. In this embodiment, the oil discharge holes 49 are formed in threes at three positions in the circumferential direction S of the outer peripheral wall 45. The oil discharge holes 49 are arranged at equal intervals in the circumferential direction S. The oil discharge holes 49 communicate the inside and the outside of the clutch center 40. The oil drain hole 49 is a hole that drains the clutch oil that has flowed out from the output shaft 15 into the clutch center 40 to the outside of the clutch center 40.

The output side rotating plate 22 is held by the splined engagement portion 46 of the clutch center 40 and the pressure plate 70. A part of the output side rotating plate 22 is held by the center side engagement teeth 47 and the spline grooves 48 of the clutch center 40 through spline engagement. Another part of the output side rotating plate 22 is held by the pressure side engagement 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 a member 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 a thin plate material made of SPCC material into an annular shape. Grooves having a depth of several μm to several tens of μm are formed on the front and back surfaces of the output side rotating plate 22 to hold clutch 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 may be provided on both the input side rotating plate 20 and the output side rotating plate 22.

The center side cam portion 60 is formed in a platform shape having a cam surface made 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 causes the input side rotating plate 20 and the output side rotating plate 22 to separate early and 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.

As shown in FIG. 3, the center side cam portion 60 is located radially outward from the output shaft holding portion 50. The center side cam portion 60 has a center side assist cam surface 60A, a center side slipper cam surface 60S, and a center side top surface 60C. The center side assist cam surface 60A is configured to generate a force in a direction that moves the pressure plate 70 closer to the clutch center 40 in order to increase 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 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. 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. The center-side top surface 60C is located between the center-side assist cam surface 60A and the center-side slipper cam surface 60S. More specifically, the center-side top surface 60C is located between the center-side assist cam surface 60A and the center-side slipper cam surface 60S in the circumferential direction S. The center-side top surface 60C is continuous with the center-side assist cam surface 60A and the center-side slipper cam surface 60S. The connection between the center top surface 60C and the center assist cam surface 60A, and the connection between the center top surface 60C and the center slipper cam surface 60S are curved surfaces.

2, the clutch center 40 has a plurality of boss portions 54 (three in this embodiment). The boss portions 54 are members that support the pressure plate 70. 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 (i.e., toward the second direction D2). The boss portions 54 are provided on the base wall 43. The boss portions 54 have a screw hole 54H formed therein, into which the bolt 28 (see FIG. 1) is inserted. The screw hole 54H extends in the axial direction of the clutch center 40.

2, the center side fitting portion 58 is located radially outward from the output shaft holding portion 50. The center side fitting portion 58 is located radially outward from the center side cam portion 60. The center side fitting portion 58 is located on the second direction D2 side from the center side cam portion 60. The center side fitting portion 58 is formed on the inner peripheral surface of the outer peripheral wall 45. The center side fitting portion 58 is configured to be slidably fitted onto the pressure side fitting portion 88 (see FIG. 4) described later. The inner diameter of the center side fitting portion 58 is formed with a fitting tolerance that allows the clutch oil flowing out from the tip portion 15T of the output shaft 15 to flow 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 this embodiment, for example, the center side fitting portion 58 is formed with an inner diameter that is 0.1 mm larger than the outer diameter of the pressure side fitting portion 88. The dimensional tolerance between the inner diameter of the center side fitting portion 58 and the outer diameter of the pressure side fitting portion 88 is set appropriately according to the amount of clutch oil to be circulated, but is, for example, 0.1 mm or more and 0.5 mm or less.

As shown in Figures 2 and 3, the clutch center 40 has a center-side cam hole 43H that penetrates a portion of the base wall 43. The center-side cam hole 43H extends 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 the center-side assist cam surface 60A of the center-side cam portion 60 and the boss portion 54. When viewed from 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.

As shown in FIG. 1, the pressure plate 70 is provided so as to be capable of approaching or separating from the clutch center 40 and of rotating relative thereto. The pressure plate 70 is configured so as to be capable of pressing the input side rotating plate 20 and the output side rotating plate 22. The pressure plate 70 is arranged 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 is connected 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 pressure plate 70 holds a plurality of output side rotating plates 22 arranged alternately with the input side rotating plates 20.

As shown in FIG. 4, the main body 72 includes a cylindrical portion 80, a plurality of pressure side cam portions 90, a pressure side fitting portion 88, and a spring housing portion 84 (see also FIG. 6).

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.

The pressure side cam portion 90 is formed in a platform shape having a cam surface made of an inclined surface that constitutes an Assist & Slipper (registered trademark) mechanism that slides against the center side cam portion 60 to generate an assist torque or a slipper torque. The pressure side cam portion 90 is formed so as to protrude in the first direction D1 beyond the flange 98. As shown in FIG. 5, the pressure side cam portions 90 are disposed 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.

As shown in FIG. 5, the pressure side cam portion 90 is located radially outward from the cylindrical portion 80. The pressure side cam portion 90 has a pressure side assist cam surface 90A (see also FIG. 7 and FIG. 9), a pressure side slipper cam surface 90S, and a pressure side top surface 90C. 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 that brings the pressure plate 70 closer to the clutch center 40 in order to increase 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 clutch center 40. 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 separate the pressure plate 70 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 clutch center 40. 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. The pressure-side top surface 90C is located between the pressure-side assist cam surface 90A and the pressure-side slipper cam surface 90S. More specifically, the pressure-side top surface 90C is located between the pressure-side assist cam surface 90A and the pressure-side slipper cam surface 90S in the circumferential direction S. The pressure side top surface 90C is continuous with the pressure side assist cam surface 90A and the pressure side slipper cam surface 90S. The connection between the pressure side top surface 90C and the pressure side assist cam surface 90A, and the connection between the pressure side top surface 90C and the pressure side slipper cam surface 90S are curved surfaces.

As shown in FIG. 8, a chamfered portion 90AP is formed at the end in the circumferential direction S of the pressure-side assist cam surface 90A of the pressure-side cam portion 90. The corner of the chamfered portion 90AP (the corner on the first direction D1 and first circumferential direction S1 side) is a right angle. More specifically, the chamfered portion 90AP is formed at the end 90AB of the pressure-side assist cam surface 90A in the first circumferential direction S1.

Here, the action of the center side cam portion 60 and the pressure side cam portion 90 will be explained. 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, as shown in FIG. 11A, a rotational force in the first circumferential direction S1 is applied to the pressure plate 70. Therefore, 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.

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, as shown in FIG. 11B, a rotational force in the first circumferential direction S1 is applied to the clutch center 40. Therefore, 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 malfunctions of the engine and transmission due to back torque.

As shown in FIG. 4, 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 second direction D2 side from the pressure side cam portion 90. The pressure side fitting portion 88 is configured to be slidably fitted into the center side fitting portion 58 (see FIG. 2).

As shown in Figures 4 and 5, the pressure plate 70 has a pressure side cam hole 73H that penetrates the main body 72 and a portion of the flange 98. The pressure side cam hole 73H is located radially outward from the cylindrical portion 80. The pressure side cam hole 73H extends from the side of the cylindrical portion 80 to a position radially outward from the pressure side fitting portion 88. 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 the adjacent pressure side cam portion 90. As shown in Figures 5 and 7, when viewed from 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.

As shown in FIG. 4, the pressure plate 70 has a plurality of pressure side mating teeth 77 arranged on a flange 98. The pressure side mating teeth 77 hold the output side rotating plate 22. The pressure side mating teeth 77 protrude from the flange 98 in a first direction D1. The pressure side mating teeth 77 are located radially outward from the cylindrical portion 80. They are located radially outward from the pressure side cam portion 90. The pressure side mating teeth 77 are located radially outward from the pressure side cam portion 90. The pressure side mating teeth 77 are located radially outward from the pressure side mating portion 88. The pressure side mating teeth 77 are aligned in the circumferential direction S. The pressure side mating teeth 77 are arranged at equal intervals in the circumferential direction S. In this embodiment, some of the pressure side mating teeth 77 have been removed, so the spacing between those teeth is wider, but the other adjacent pressure side mating teeth 77 are spaced equally apart.

As shown in Figures 6 and 7, the spring accommodating portion 84 is formed in the pressure side cam portion 90. The spring accommodating portion 84 is formed so as to be recessed from the second direction D2 to the first direction D1. The spring accommodating portion 84 is formed in an elliptical shape. The spring accommodating portion 84 accommodates the pressure spring 25 (see Figure 1). An insertion hole 84H into which the boss portion 54 (see Figure 2) is inserted is formed through the spring accommodating portion 84. That is, the insertion hole 84H is formed through the pressure side cam portion 90. The insertion hole 84H is formed in an elliptical shape.

As shown in FIG. 1, the pressure spring 25 is housed in the spring housing 84. The pressure spring 25 is held by the boss 54 inserted into the insertion hole 84H of the spring housing 84. The pressure spring 25 biases the pressure plate 70 toward the clutch center 40 (i.e., toward the first direction D1). The pressure spring 25 is, for example, a coil spring made of spring steel wound in a spiral shape.

Figure 10 is a plan view showing the state in which the clutch center 40 and the pressure plate 70 are combined. In the state shown in Figure 10, the pressure side assist cam surface 90A and the center side assist cam surface 60A are not in contact, and the pressure side slipper cam surface 90S and the center side slipper cam surface 60S are not in contact. At this time, the pressure plate 70 is closest to the clutch center 40. This state is the normal state of the clutch device 10. As shown in Figure 10, the distance L5 in the circumferential direction S between the boss portion 54 and the end 84HA on the pressure side assist cam surface 90A side (i.e., the first circumferential direction S1 side) of the insertion hole 84H in the normal state is longer than the distance L6 in the circumferential direction S between the boss portion 54 and the end 84HB on the pressure side slipper cam surface 90S side (i.e., the second circumferential direction S2 side) of the insertion hole 84H in the normal state.

Figure 12 is a cross-sectional view of an enlarged portion of the pressure plate 70 and the clutch center 40. Figure 12 is a cross-sectional view taken along XII-XII in Figure 10. That is, Figure 12 is a cross-sectional view taken along a plane passing through the axis 54C of the boss portion 54 and extending in the circumferential direction S and the axial direction of the output shaft 15. As shown in Figure 12, when the center side top surface 60C and the pressure side top surface 90C are located at the same position with respect to the direction D and the end 60AA of the center side assist cam surface 60A in the second direction D2 faces the end 90AA of the pressure side assist cam surface 90A in the first direction D1, the end 90SA of the pressure side slipper cam surface 90S in the first direction D1 is located on the first circumferential direction S1 side of the end 60SA of the center side slipper cam surface 60S in the second direction D2. A gap is formed between the end 60SA and the end 90SA in the circumferential direction S. When the center side top surface 60C and the pressure side top surface 90C are located at the same position in the moving direction D and the end 84HA on the pressure side assist cam surface 90A side of the insertion hole 84H is in contact with the boss portion 54, the end 60AA of the center side assist cam surface 60A in the second direction D2 is located closer to the first circumferential direction S1 side than the end 90AA of the pressure side assist cam surface 90A in the first direction D1. A gap is formed between the end 60AA and the end 90AA in the circumferential direction S. The center side top surface 60C and the pressure side top surface 90C being located at the same position in the direction D means that the center side top surface 60C and the pressure side top surface 90C are in contact with each other when the center side top surface 60C and the pressure side top surface 90C are located at the same position in the circumferential direction S.

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 a member that prevents the pressure plate 70 from moving away from the clutch center 40 by more than a predetermined distance in the second direction D2. The stopper plate 100 is fixed to the boss portion 54 of the clutch center 40 by the bolt 28. The pressure plate 70 is fixed by tightening the bolt 28 to the boss portion 54 via the stopper plate 100 with the boss portion 54 of the clutch center 40 and the pressure spring 25 arranged in the spring accommodating portion 84. The stopper plate 100 is formed in a substantially triangular shape in a plan view.

Here, when the pressure plate 70 contacts the stopper plate 100, the pressure side slipper cam surface 90S and the center side slipper cam surface 60S are in contact with each other over 50% to 90% of the area of the pressure side slipper cam surface 90S and over 50% to 90% of the area of the center side slipper cam surface 60S. Also, when the pressure plate 70 contacts the stopper plate 100, the pressure spring 25 is separated from the side wall of the spring housing portion 84. That is, the pressure spring 25 is not sandwiched between the boss portion 54 and the spring housing portion 84, and excessive stress is prevented from being applied to the boss portion 54.

Here, the length L1 (see FIG. 5) in the circumferential direction S from the end 90AA in the first direction D1 of the pressure side assist cam surface 90A located on the first circumferential direction S1 side of one pressure side cam portion 90L among the pressure side cam portions 90 adjacent to each other in the circumferential direction S to the end 90SA in the first direction D1 of the pressure side slipper cam surface 90S located on the second circumferential direction S2 side of the other pressure side cam portion 90M is longer than the length L2 (see FIG. 3) in the circumferential direction from the end 60AA in the second direction D2 of the center side assist cam surface 60A of one center side cam portion 60 to the end 60SA in the second direction D2 of the center side slipper cam surface 60S.

In addition, when viewed from the axial direction of the output shaft 15, the angle θ1 (see FIG. 5) between the center of the pressure plate 70 (here, the center 80C of the cylindrical portion 80) and the end 90AB in the first circumferential direction S1 of the pressure side assist cam surface 90A located on the first circumferential direction S1 side of one of the pressure side cam portions 90L adjacent to each other in the circumferential direction S, and the end 90SB in the first circumferential direction S1 of the pressure side slipper cam surface 90S located on the second circumferential direction S2 side of the other pressure side cam portion 90M is greater than the angle θ2 (see FIG. 3) between the center 50C of the output shaft holding portion 50 and the end 60AB in the second circumferential direction S2 of the center side assist cam surface 60A of one center side cam portion 60, and the end 60SB in the second circumferential direction S2 of the center side slipper cam surface 60S. Angle θ1 is the angle between a line passing through center 80C and end 90AB of tubular portion 80 and a line passing through center 80C and end 90SB. Angle θ2 is the angle between a line passing through center 50C and end 60AB of output shaft holding portion 50 and a line passing through center 50C and end 60SB.

In addition, the length L3 (see FIG. 3) in the circumferential direction S from the end 60AA in the second direction D2 of the center-side assist cam surface 60A to the boss portion 54 is longer than the length L4 (see FIG. 5) in the circumferential direction S from the end 90AA in the first direction D1 of the pressure-side assist cam surface 90A to the insertion hole 84H.

Also, when viewed from the axial direction of the output shaft 15, the angle θ3 (see FIG. 3) between the center 50C of the output shaft holding portion 50, the end 60AB in the second circumferential direction S2 of the center side assist cam surface 60A of the center side cam portion 60, and the axis 54C of the boss portion 54 is greater than the angle θ4 (see FIG. 5) between the center of the pressure plate 70 (here, the center 80C of the cylindrical portion 80), the end 90AB in the first circumferential direction S1 of the pressure side assist cam surface 90A, and the center 84HC of the insertion hole 84H. The angle θ3 is the angle between a straight line passing through the center 50C and the end 60AB of the output shaft holding portion 50 and a straight line passing through the center 50C and the axis 54C of the boss portion 54. The angle θ4 is the angle between a straight line passing through the center 80C of the cylindrical portion 80 and the end portion 90AB, and a straight line passing through the center 80C and the center 84HC of the insertion hole 84H.

The clutch device 10 is filled with a predetermined amount of clutch oil. The clutch oil flows through the hollow portion 15H of the output shaft 15 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 the oil discharge hole 49. The clutch oil absorbs heat and prevents wear of the friction material. The clutch device 10 of this embodiment is a so-called wet-type multi-plate friction clutch device.

Next, the operation of the clutch device 10 of this embodiment will be described. As described above, the clutch device 10 is disposed between the engine and the transmission of the motorcycle, and the driver operates the clutch operating lever to transmit or cut off the rotational driving force of the engine to the transmission.

When the rider of the motorcycle does not operate the clutch operating lever, the clutch release mechanism (not shown) does not press the push rod 16A, and the pressure plate 70 presses the input side rotating plate 20 by the biasing force (elastic force) of the pressure spring 25. As a result, the clutch center 40 is in a clutch-on state in which the input side rotating plate 20 and the output side rotating plate 22 are pressed against each other and frictionally connected, and the clutch center 40 rotates. In other words, the rotational driving force of the engine is transmitted to the clutch center 40, and the output shaft 15 rotates.

When the clutch is ON, the clutch oil that flows through the hollow portion H of the output shaft 15 and flows out from the tip end 15T of the output shaft 15 falls or flies into the cylindrical portion 80 and adheres thereto (see arrow F in FIG. 1). The clutch oil that adheres to the cylindrical portion 80 is guided into the clutch center 40. As a result, the clutch oil flows out of the clutch center 40 through the oil discharge hole 49. The clutch oil also flows out of the clutch center 40 through the gap between the center side fitting portion 58 and the pressure side fitting portion 88. The clutch oil that flows out of the clutch center 40 is then supplied to the input side rotating plate 20 and the output side rotating plate 22.

On the other hand, when the rider of the motorcycle operates the clutch operating lever while the clutch is in the clutch ON state, the clutch release mechanism (not shown) presses the push rod 16A, displacing the pressure plate 70 in a direction (second direction D2) away from the clutch center 40 against the biasing force of the pressure spring 25. As a result, the clutch center 40 enters a clutch OFF state in which the frictional connection between the input side rotating plate 20 and the output side rotating plate 22 is released, and the rotational drive is attenuated or stopped. In other words, the rotational drive force of the engine is cut off from the clutch center 40.

In the clutch OFF state, the clutch oil that flows inside the hollow portion H of the output shaft 15 and flows out from the tip portion 15T of the output shaft 15 is guided into the clutch center 40, just as in the clutch ON state. At this time, the pressure plate 70 is separated from the clutch center 40, so the amount of engagement between the center side fitting portion 58 and the pressure side fitting portion 88 decreases. As a result, the clutch oil in the cylindrical portion 80 flows out more actively to the outside of the clutch center 40 and to various places inside the clutch device 10. In particular, the clutch 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.

When the driver releases the clutch operating lever in the clutch-off state, the pressure applied to the pressure plate 70 by the clutch release mechanism (not shown) via the push member 16B is released, and the pressure plate 70 is displaced in a direction approaching the clutch center 40 (first direction D1) by the biasing force of the pressure spring 25.

As described above, according to the clutch device 10 of this embodiment, when the center side top surface 60C and the pressure side top surface 90C are located at the same position with respect to direction D and the end 60AA in the second direction D2 of the center side assist cam surface 60A faces the end 90AA in the first direction D1 of the pressure side assist cam surface 90A, the end 90SA in the first direction D1 of the pressure side slipper cam surface 90S is located on the first circumferential direction S1 side of the end 60SA in the second direction D2 of the center side slipper cam surface 60S. According to the above aspect, when the pressure plate 70 is assembled to the clutch center 40, the end 60AA in the second direction D2 of the center side assist cam surface 60A and the end 90AA in the first direction D1 of the pressure side assist cam surface 90A do not interfere with each other, and the pressure plate 70 can be moved in the first direction D1 relative to the clutch center 40 along the pressure side slipper cam surface 90S along the center side slipper cam surface 60S, so that the pressure plate 70 and the clutch center 40 can be easily assembled.

In the clutch device 10 of this embodiment, when the center-side top surface 60C and the pressure-side top surface 90C are located at the same position in the direction D and the end 84HA of the pressure-side assist cam surface 90A side of the insertion hole 84H is in contact with the boss portion 54, the end 60AA of the center-side assist cam surface 60A in the second direction D2 is located closer to the first circumferential direction S1 than the end 90AA of the pressure-side assist cam surface 90A in the first direction D1. According to the above aspect, when the pressure plate 70 is assembled to the clutch center 40, interference between the end 60AA of the center-side assist cam surface 60A in the second direction D2 and the end 90AA of the pressure-side assist cam surface 90A in the first direction D1 can be more reliably suppressed.

Second Embodiment
FIG. 13 is a cross-sectional view of a part of the pressure plate 70 and the clutch center 40 according to the second embodiment, which is enlarged. FIG. 13 corresponds to a cross-sectional view cut by a plane passing through the axis 54C of the boss portion 54 and extending in the circumferential direction S and the axial direction of the output shaft 15. As shown in FIG. 13, the pressure plate 70 includes a ring-shaped spring seat 85 housed in a spring housing portion 84. The ring-shaped spring seat 85 includes, for example, an O-shape (O-ring) and a C-shape (C-ring). The spring seat 85 is formed in an elliptical shape. The spring seat 85 is arranged so as to be movable in the circumferential direction S within the spring housing portion 84. In the example shown in FIG. 13, the spring seat 85 is located closest to the second circumferential direction S2 in the spring housing portion 84. That is, an end portion 85A of the spring seat 85 in the second circumferential direction S2 contacts an inner wall 84A of the spring housing portion 84. The boss portion 54 penetrates the spring seat 85. The pressure spring 25 is disposed on a surface 85M of the spring seat 85 facing the second direction D2.

13, when the center-side top surface 60C and the pressure-side top surface 90C are located at the same position in the moving direction D, the sum of the first length LS1 and the second length LS2 is longer than the third length LS3. That is, (LS1 + LS2) > LS3 is established. Here, the first length LS1 is the distance in the circumferential direction S between the end 60AA of the center-side assist cam surface 60A in the second direction D2 and the end 90AA of the pressure-side assist cam surface 90A in the first direction D1. The second length LS2 is the distance in the circumferential direction S between the end 60SA of the center-side slipper cam surface 60S in the second direction D2 and the end 90SA of the pressure-side slipper cam surface 90S in the first direction D1. The third length LS3 is the distance in the circumferential direction S between the first inner edge 85HA and the end 84HA when the spring seat 85 is located closest to the second circumferential direction S2 side in the spring accommodating portion 84, the first inner edge 85HA, which is the inner edge of the spring seat 85 on the first circumferential direction S1 side, is in contact with the boss portion 54, and the end 84HA, which is the inner edge of the insertion hole 84H on the first circumferential direction S1 side, is not in contact with the boss portion 54. The end 84HA is an example of the first inner edge.

As described above, according to the clutch device 10 of this embodiment, in a cross-sectional view taken along a plane that passes through the axis 54C of the boss portion 54 and extends in the circumferential direction S and the axial direction of the output shaft 15, when the center-side top surface 60C and the pressure-side top surface 90C are positioned at the same position with respect to the direction D, the first length LS1, which is the distance in the circumferential direction S between the end 60AA in the second direction D2 of the center-side assist cam surface 60A and the end 90AA in the first direction D1 of the pressure-side assist cam surface 90A, and the first length LS2, which is the distance in the circumferential direction S between the end 60SA in the second direction D2 of the center-side slipper cam surface 60S and the end 90SA in the first direction D1 of the pressure The total length (LS1 + LS2) of the spring seat 85 and the second length LS2 which is the distance in the circumferential direction S from the end 90SA of the clutch-side slipper cam surface 90S in the first direction D1 is longer than a third length LS3 which is the distance in the circumferential direction S between the first inner edge 85HA and the end 84HA when the spring seat 85 is located closest to the second circumferential direction S2 side in the spring accommodating portion 84, the first inner edge 85HA which is the inner edge of the spring seat 85 on the first circumferential direction S1 side is in contact with the boss portion 54, and the end 84HA which is the inner edge of the insertion hole 84H on the first circumferential direction S1 side is not in contact with the boss portion 54. According to the above aspect, even when the spring seat 85 is accommodated in the spring accommodating portion 84, the pressure plate 70 and the clutch center 40 can be easily assembled. For example, if the total length (LS1 + LS2) is shorter than the third length, when attempting to assemble the pressure plate 70 to the clutch center 40 with the spring seat 85 housed in the spring housing portion 84, the end 60AA of the center side assist cam surface 60A in the second direction D2 and the end 90AA of the pressure side assist cam surface 90A in the first direction D1 will interfere with each other, so the spring seat 85 must be housed in the spring housing portion 84 after the pressure plate 70 is assembled to the clutch center 40, making the assembly process complicated.

In the clutch device 10 of this embodiment, the connection between the pressure side slipper cam surface 90S and the pressure side top surface 90C is a curved surface. According to the above aspect, when assembling the pressure plate 70 to the clutch center 40, it becomes easier to slide the pressure plate 70 on the center side slipper cam surface 60S, so that the pressure plate 70 and the clutch center 40 can be easily assembled.

The above describes a preferred embodiment of the present invention. However, the above embodiment is merely an example, and the present invention can be implemented in various other forms.

10 Clutch device 15 Output shaft 20 Input side rotating plate 22 Output side rotating plate 25 Pressure spring 30 Clutch housing 40 Clutch center 50 Output shaft holding portion 54 Boss portion 54C Shaft center 60 Center side cam portion 60A Center side assist cam surface 60AA End portion in second direction 60C Center side top surface 60S Center side slipper cam surface 60SA End portion in second direction 70 Pressure plate 84 Spring accommodating portion 84H Insertion hole 85 Spring seat 90 Pressure side cam portion 90A Pressure side assist cam surface 90AA End portion in first direction 90C Pressure side top surface 90S Pressure side slipper cam surface 90SA End portion in first direction D1 First direction D2 Second direction S1 First circumferential direction S2 Second circumferential direction

Claims (1)

A clutch device that transmits or cuts off the rotational driving force of an input shaft to an output shaft,
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, holds a plurality of output side rotating plates that are arranged alternately with the input side rotating plates, and is rotationally driven together with the output shaft;
a pressure plate that is provided so as to be capable of approaching or separating from the clutch center and rotatable relative to the clutch center and that can press the input side rotating plate and the output side rotating plate,
The clutch center is
an output shaft holding portion to which the output shaft is connected;
a plurality of center side cam portions each having a center side assist cam surface located radially outward of the output shaft holding portion and generating a force in a direction that moves the pressure plate closer to the clutch center in order to increase the pressing force between the input side rotating plate and the output side rotating plate when the center side cam portions rotate relative to the pressure plate, a center side slipper cam surface that moves the pressure plate away from the clutch center in order to decrease the pressing force between the input side rotating plate and the output side rotating plate, and a center side top surface located between the center side assist cam surface and the center side slipper cam surface;
a boss portion located radially outward from the output shaft holding portion and extending toward the pressure plate,
The pressure plate is
a plurality of pressure-side cam portions each having a pressure-side assist cam surface configured to be capable of contacting the center-side assist cam surface when rotating relative to the clutch center, and generating a force in a direction that brings the pressure plate closer to the clutch center in order to increase the pressing force between the input side rotating plate and the output side rotating plate, a pressure-side slipper cam surface configured to be capable of contacting the center-side slipper cam surface, and moving the pressure plate away from the clutch center in order to reduce the pressing force between the input side rotating plate and the output side rotating plate, and a pressure-side top surface located between the pressure-side assist cam surface and the pressure-side slipper cam surface;
a spring accommodating portion that is formed in the pressure side cam portion so as to be recessed from the second direction to the first direction, when a direction in which the pressure plate approaches and moves away from the clutch center is defined as a movement direction, 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 that accommodates a pressure spring that urges the pressure plate in the first direction;
A ring-shaped spring seat is accommodated in the spring accommodating portion,
The spring accommodating portion has an insertion hole through which the boss portion is inserted,
a first circumferential direction is a direction from one of the pressure side cam portions to the other of the pressure side cam portions, and a second circumferential direction is a direction from the other of the pressure side cam portions to one of the pressure side cam portions, the clutch center and the pressure plate are configured to rotate in the first circumferential direction,
In a state in which the center-side top surface and the pressure-side top surface are located at the same position with respect to the moving direction, the end of the center-side assist cam surface in the second direction faces the end of the pressure-side assist cam surface in the first direction with respect to the circumferential direction, and the second circumferential end of the spring seat and the second circumferential end of the spring accommodating portion abut against each other, the boss portion is disposed to penetrate the insertion hole and the spring seat , the boss portion contacts the first circumferential end of the inner edge of the spring seat, and the first direction end of the pressure-side assist cam surface abuts against the center-side top surface and the second circumferential end of the spring seat and the second circumferential end of the spring accommodating portion. a first circumferential direction end of the pressure-side slipper cam surface is located on the second circumferential direction side of the second direction end of the pressure-side assist cam surface, the first direction end of the pressure-side slipper cam surface is located on the first circumferential direction side of the second direction end of the center-side slipper cam surface, a gap is formed in the circumferential direction between the first circumferential direction end of the inner edge of the insertion hole and the boss portion, and the circumferential distance between the second direction end of the center-side slipper cam surface and the first direction end of the pressure-side slipper cam surface is longer than the circumferential distance between the first circumferential direction end of the inner edge of the insertion hole and the boss portion .

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