Clutch device

Abstract

To provide a clutch device in which sudden connection of the clutch is suppressed. 【Solution means】The clutch device 10 includes a clutch spring 25 that biases the pressure plate 70 in the first direction D1, and a stopper plate 100 fixed to the clutch center 40. The axis 25L of the clutch spring 25 is inclined toward the pressure-side slipper cam surface side 90S from the end 25D1 in the first direction D1 to the end 25D2 in the second direction D2 in a cross-sectional view along the circumferential direction S of the clutch center 40 and the pressure plate 70 when the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are in contact, and is parallel to a straight line extending in the direction D when the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are most separated in the rotational direction S.

Description

Technical Field

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

Background Art

[0002] Conventionally, vehicles such as motorcycles are equipped with a clutch device. For example, Patent Document 1 discloses a clutch device including a clutch center that holds an output-side rotating plate, a pressure plate that is provided so as to be able to approach and separate from the clutch center, and a clutch spring that biases the pressure plate toward the clutch center. The clutch spring is housed in a housing portion 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. Further, the clutch center and the pressure plate of the clutch device of Patent Document 1 each have a center-side assist cam surface and a pressure-side assist cam surface that generate a force in a direction from the pressure plate toward the clutch center when the rotational driving 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 rotation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, when the clutch shifts from the engaged state to the disengaged state, that is, when the center-side assist cam surface and the pressure-side assist cam surface shift from the contacting state to the separated state, the pressure plate moves in a direction away from the clutch center while relatively rotating in the circumferential direction with respect to the clutch center. For this reason, a restoring force (i.e., a restoring force attempting to return to the state where the center-side assist cam surface and the pressure-side assist cam surface are in contact) in a direction from the clutch spring toward the pressure-side assist cam surface can be generated in the clutch spring housed in the housing portion. If such a restoring force is too large, when the clutch shifts from the disengaged state to the engaged state, the center-side assist cam surface and the pressure-side assist cam surface may suddenly come into contact due to the restoring force, and there is a risk that the clutch will suddenly engage.

[0005] The present invention has been made in view of such a point, and an object thereof is to provide a clutch device in which sudden engagement of the clutch is suppressed.

Means for Solving the Problems

[0006] The clutch device according to the present invention is a clutch device that transmits or shuts off the rotational driving force of an input shaft to an output shaft, and is housed in a clutch housing that holds a plurality of input-side rotating plates that are rotationally driven by the rotational driving of the input shaft. It includes a clutch center that rotates together with the output shaft, a plurality of output-side rotating plates that are provided so as to be able to approach or separate from and rotate relative to the clutch center, and are alternately arranged with the input-side rotating plates, and a pressure plate that can press the input-side rotating plates and the output-side rotating plates. When the first direction is the direction in which the pressure plate approaches the clutch center and the second direction is the direction in which the pressure plate separates from the clutch center, it includes a clutch spring that biases the pressure plate in the first direction, a stopper plate that is fixed to the clutch center and suppresses the pressure plate from separating from the clutch center in the second direction by a predetermined distance or more. The end of the clutch spring in the first direction contacts the pressure plate, and the end of the clutch spring in the second direction contacts the stopper plate. The clutch center has a center-side assist cam surface that generates a force in the direction from the pressure plate toward the clutch center in order to increase the pressing force between the input-side rotating plate and the output-side rotating plate when the clutch center rotates relative to the pressure plate. The pressure plate is configured to be able to contact the center-side assist cam surface when rotating relative to the clutch center and has a pressure-side assist cam surface that generates a force in the direction from the pressure plate toward the clutch center in order to increase the pressing force between the input-side rotating plate and the output-side rotating plate, and a housing portion that is arranged side by side with the pressure-side assist cam surface in the rotational direction of the pressure plate and houses the clutch spring. It has a reducing means for reducing the restoring force of the clutch spring in the direction from the clutch spring toward the pressure-side assist cam surface until the center-side assist cam surface and the pressure-side assist cam surface come into contact with each other while being separated from each other in the rotational direction.

[0007] According to the clutch device of the present invention, the reducing means reduces the restoring force in the direction from the clutch spring toward the pressure-side assist cam surface in the clutch spring until the center-side assist cam surface and the pressure-side assist cam surface come into contact with each other while being separated from each other in the rotational direction. In this way, since the restoring force that can be generated in the clutch spring is reduced by the reducing means, it is suppressed that the center-side assist cam surface and the pressure-side assist cam surface come into contact suddenly due to the restoring force. That is, it is possible to suppress the clutch from being suddenly engaged by the reducing means.

[0008] 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 is housed in a clutch housing that holds a plurality of input-side rotating plates that are rotationally driven by the rotational driving of the input shaft. A clutch center that rotates together with the output shaft, and a plurality of output-side rotating plates that are provided so as to be able to approach or separate from and relatively rotate with respect to the clutch center, and are alternately arranged with the input-side rotating plates, and hold the input-side rotating plates and the output-side rotating plates A pressure plate capable of pressing, and when the direction in which the pressure plate approaches the clutch center is the first direction and the direction in which the pressure plate separates from the clutch center is the second direction, a clutch spring that biases the pressure plate in the first direction, and is fixed to the pressure plate, And a lifter plate that suppresses the pressure plate from separating from the clutch center by a predetermined distance or more in the second direction, and an end portion of the clutch spring in the first direction contacts the lifter plate, and the clutch spring The end portion in the second direction contacts the clutch center, and when the clutch center rotates relative to the pressure plate, a center-side assist cam surface that generates a force in a direction from the pressure plate toward the clutch center to increase the pressing force between the input-side rotating plate and the output-side rotating plate, and the center-side assist cam surface in relation to the rotation direction of the clutch center And a housing portion that houses the clutch spring, and the pressure plate is configured to be able to contact the center-side assist cam surface when rotating relative to the clutch center, and the pressure plate generates a force in a direction from the pressure plate toward the clutch center to increase the pressing force between the input-side rotating plate and the output-side rotating plate. And a pressure-side assist cam surface, and reduction means for reducing the restoring force of the clutch spring in a direction from the clutch spring toward the center-side assist cam surface in the clutch spring until the center-side assist cam surface and the pressure-side assist cam surface approach and contact each other in the rotation direction.

[0009] According to another clutch device of the present invention, the reduction means reduces the restoring force in the direction from the clutch spring toward the center side assist cam surface in the clutch spring until the center side assist cam surface and the pressure side assist cam surface come into contact with each other while being separated from each other in the rotational direction. In this way, since the restoring force that can be generated in the clutch spring is reduced by the reduction means, it is possible to suppress the sudden contact between the center side assist cam surface and the pressure side assist cam surface due to the restoring force. That is, it is possible to suppress the sudden connection of the clutch by the reduction means.

Effects of the Invention

[0010] According to the present invention, it is possible to provide a clutch device in which the sudden connection of the clutch is suppressed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8A

Figure 8B

Figure 9

Figure 10A

Figure 10B

Figure 11A

Figure 11B

Figure 12

Figure 13

Figure 14A

Figure 14B

Figure 15A

Figure 15B

DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the clutch device according to the present invention will be described with reference to the drawings. It should be noted that the embodiments described here are not intended to limit the present invention in particular. Also, members and parts having the same function are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified as appropriate.

[0013] <First Embodiment> FIG. 1 is a cross-sectional view of a clutch device 10 according to the present embodiment. The clutch device 10 is provided in a vehicle such as a motorcycle, for example. The clutch device 10 is a device that transmits or interrupts the rotational driving force of the input shaft (crankshaft) of an engine of a motorcycle to the output shaft 15, for example. The clutch device 10 is a device for transmitting or interrupting the rotational driving force of the input shaft to the drive wheel (rear wheel) via the output shaft 15. 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 separates from the clutch center 40 is defined as the direction D (an example of the moving direction), the direction in which the pressure plate 70 approaches the clutch center 40 is defined as the first direction D1, and the direction in which the pressure plate 70 separates from the clutch center 40 is defined as the second direction D2. Also, the rotational direction (i.e., the circumferential direction) of the clutch center 40 and the pressure plate 70 is defined as the rotational direction S, the direction from one pressure-side cam portion 90 to the other pressure-side cam portion 90 with respect to the rotational direction S is defined as the first rotational direction S1 (see FIG. 5), and the direction from the other pressure-side cam portion 90 to one pressure-side cam portion 90 is defined as the second rotational direction S2 (see FIG. 5). In the present 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. Also, the pressure plate 70 and the clutch center 40 rotate in the first rotational direction S1. However, the above directions are merely defined for convenience of explanation and do not limit the installation mode of the clutch device 10 in any way, nor do they limit the present invention in any way.

[0015] As shown in FIG. 1, the clutch device 10 includes an output shaft 15, an input-side rotating plate 20, an output-side rotating plate 22, a clutch housing 30, a clutch center 40, a pressure plate 70, a stopper plate 100, a clutch spring 25, and a reducing means 110. The clutch device 10 is a so-called internal cut type clutch device.

[0016] As shown in FIG. 1, the output shaft 15 is a shaft body formed in a hollow shape. One end of the output shaft 15 rotatably supports an input gear 35 and a clutch housing 30, which will be described later, via a needle bearing 15A. The output shaft 15 fixedly supports the 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 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, that is, inside the hollow portion 15H. The push rod 16A and the push member 16B are slidably provided inside 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 (such as a clutch operation lever or an operation button) of a motorcycle, and slides inside the hollow portion 15H by the driver's clutch operation to press the push member 16B in the second direction D2. A part of the push member 16B protrudes outward (here, in the second direction D2) of the output shaft 15 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 thinner than the inner diameter of the hollow portion 15H, and the fluidity of the clutch oil is ensured inside the hollow portion 15H.

[0018] The clutch housing 30 is formed from an aluminum alloy. The clutch housing 30 is formed in a bottomed cylindrical shape. 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 the edge of the bottom wall 31 in the second direction D2. The clutch housing 30 holds a plurality of input-side rotating plates 20.

[0019] 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 by 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.

[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 (i.e., direction D) of the clutch housing 30. 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. A friction material (not shown) made of a plurality of pieces of paper is attached to the front and back surfaces of the input-side rotating plate 20. Grooves with a depth of several hundred μm for holding clutch oil are formed between the friction materials.

[0022] 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 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 a plurality of output-side rotating plates 22 alternately arranged with the input-side rotating plate 20 in the direction D. The clutch center 40 is rotationally driven together with the output shaft 15.

[0023] As shown in FIG. 2, the main body 42 includes an annular base wall 43, an outer peripheral wall 45 located radially outside the base wall 43 and extending toward the second direction D2, an output shaft holding portion 50 provided at 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. An insertion hole 51 into which the output shaft 15 (see FIG. 1) is inserted and spline-fitted is formed in the output shaft holding portion 50. The insertion hole 51 is formed to penetrate the base wall 43. A plurality of spline grooves are formed along the axial direction on the inner peripheral surface 50A of the output shaft holding portion 50 that forms the insertion hole 51. 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 outside 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 plurality of center-side fitting teeth 47 are arranged in the rotational direction S. The plurality of center-side fitting teeth 47 are formed at equal intervals in the rotational direction S. The plurality of center-side fitting teeth 47 are formed in the same shape. The center-side fitting teeth 47 project 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 part of the output-side rotating plate 22 is held by spline fitting with the center-side fitting teeth 47 and the spline grooves 48 of the clutch center 40. Another part of the output-side rotating plate 22 is held by the pressure-side fitting teeth 77 (see FIG. 4) of the pressure plate 70 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.

[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 annularly punching a thin plate material made of SPCC material. Note that 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 each of 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 trapezoidal shape having a cam surface formed of an inclined surface that constitutes an assist & slipper (registered trademark) mechanism that generates an assist torque, which is a force for increasing the pressing force (contact force) between the input side rotating plate 20 and the output side rotating plate 22, or a slipper torque, which is a force for quickly separating the input side rotating plate 20 and the output side rotating plate 22 and shifting to a semi-clutch state. The center side cam portion 60 is formed so as 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 rotation direction S of the clutch center 40. In the present embodiment, the clutch center 40 has three center side cam portions 60, but the number of the 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 outside 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 the direction from the pressure plate 70 toward the clutch center 40 (here, the first direction D1) in order to increase the pressing force (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 present embodiment, when the above force is generated, the position of the pressure plate 70 with respect to the clutch center 40 does not change, and it is not necessary for the pressure plate 70 to physically approach the clutch center 40. Note that the pressure plate 70 may be physically displaced with respect to the clutch center 40. The center side slipper cam surface 60S is configured to separate the pressure plate 70 from the clutch center 40 in order to decrease the pressing force (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 with respect to the rotation 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 to face each other in the rotation direction S.

[0030] As shown in FIG. 2, the clutch center 40 includes a plurality (three in this embodiment) of boss portions 54. The boss portion 54 is a member that supports the stopper plate 100 (see FIG. 1). The plurality of boss portions 54 are arranged at equal intervals in the rotational direction S. The boss portion 54 is formed in a cylindrical shape. The boss portion 54 is located radially outside the output shaft holding portion 50. The boss portion 54 extends toward the pressure plate 70 (i.e., in the second direction D2). The boss portion 54 is provided on the center side cam portion 60. The boss portion 54 is located between the center side assist cam surface 60A and the center side slipper cam surface 60S with respect to the rotational direction S. A screw hole 54H is formed in the boss portion 54. The screw hole 54H extends in the axial direction of the clutch center 40. A bolt 28 (see FIG. 1) used to fix the stopper plate 100 to the clutch center 40 is inserted into the screw hole 54H.

[0031] As shown in FIGS. 2 and 3, the clutch center 40 has a center side cam hole 43H that penetrates a part 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 one center side cam portion 60 and the center side slipper cam surface 60S of the other center side cam portion 60. When viewed from the axial direction of the clutch center 40, a part of the center side assist cam surface 60A overlaps with the center side cam hole 43H.

[0032] As shown in FIG. 1, the pressure plate 70 is provided so as to be able to approach or separate from the clutch center 40 and to be relatively rotatable. The pressure plate 70 is configured to be able to press 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 from the flange 98. The flange 98 is located at the outer diameter end of the pressure plate 70. The flange 98 is located radially outside the cylindrical portion 80 (also see FIG. 4) described later. The pressure plate 70 holds a plurality of output-side rotating plates 22 alternately arranged with the input-side rotating plate 20. The flange 98 is configured to be able to press the input-side rotating plate 20 and the output-side rotating plate 22.

[0033] As shown in FIG. 4, the main body 72 includes a cylindrical portion 80, a plurality of pressure-side cam portions 90, and a spring housing portion 84 (see FIG. 6). The spring housing portion 84 is an example of a housing 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 houses the tip portion 15T (see FIG. 1) of the output shaft 15. The release bearing 18 (see FIG. 1) is housed in the cylindrical portion 80. 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 flowing 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 trapezoidal shape having a cam surface composed 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 so as to protrude in the first direction D1 from the flange 98. As shown in FIG. 5, the pressure-side cam portions 90 are arranged at equal intervals in the rotation direction S of the pressure plate 70. In the present 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 on the outer side in the radial direction 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 in contact with the center-side assist cam surface 60A. When the pressure-side assist cam surface 90A rotates relative to the clutch center 40, it is configured to generate a force in the direction from the pressure plate 70 toward the clutch center 40 in order to increase the pressing force (contact pressure) between the input-side rotating plate 20 and the output-side rotating plate 22. The pressure-side slipper cam surface 90S is configured to be in contact with the center-side slipper cam surface 60S. When the pressure-side slipper cam surface 90S rotates relative to the clutch center 40, it is configured to separate the pressure plate 70 from the clutch center 40 in order to decrease the pressing force (contact pressure) 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 with respect to the rotation 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 to face each other in the rotation direction S.

[0037] Here, the operations 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, as shown in FIG. 8A, a rotational force in the first rotational direction S1 is applied to the pressure plate 70. For this reason, due to the operations 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. As a result, the pressure plate 70 moves in a direction closer to the clutch center 40 (the first direction D1) to increase the pressing 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 speeds of the input gear 35 and the clutch housing 30 and a back torque occurs, as shown in FIG. 8B, a rotational force in the first rotational direction S1 is applied to the clutch center 40. For this reason, due to the operations of the center-side slipper cam surface 60S and the pressure-side slipper cam surface 90S, the pressure plate 70 is moved in the second direction D2 to release the pressing contact force between the input-side rotating plate 20 and the output-side rotating plate 22. As a result, problems with respect to the engine and the transmission due to the back torque can be avoided.

[0039] As shown in FIGS. 4 and 5, the pressure plate 70 has a pressure-side cam hole 73H that penetrates a part of the main body 72. The pressure-side cam hole 73H is located radially outside the cylindrical portion 80. The pressure-side cam hole 73H extends from the side of the cylindrical portion 80 to radially outside 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 FIGS. 5 and 7, when viewed from the axial direction of the pressure plate 70, a part of the pressure-side assist cam surface 90A overlaps with a part of the pressure-side cam hole 73H. When the clutch center 40 and the pressure plate 70 are combined, the boss portion 54 of the clutch center 40 is located within the pressure-side cam hole 73H.

[0040] As shown in FIG. 4, the pressure plate 70 includes a plurality of pressure-side fitting teeth 77 formed on the outer peripheral 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 on the S1 side in the first direction from the flange 98. The pressure-side fitting teeth 77 are located radially outside the cylindrical portion 80. The pressure-side fitting teeth 77 are located radially outside the pressure-side cam portion 90. The pressure-side fitting teeth 77 are located radially outside the pressure-side cam portion 90. The plurality of pressure-side fitting teeth 77 are arranged in the rotational direction S. The plurality of pressure-side fitting teeth 77 are arranged at equal intervals in the rotational direction S. In this embodiment, since some of the pressure-side fitting teeth 77 are removed, the interval of this part is widened, but the other adjacent pressure-side fitting teeth 77 are arranged at equal intervals.

[0041] As shown in FIGS. 6 and 7, the spring housing portion 84 is formed in the pressure side cam portion 90. The spring housing portion 84 is formed to be recessed from the second direction D2 toward the first direction D1. The spring housing portion 84 is formed in an elliptical shape when viewed from the direction D (see also FIG. 9). The spring housing portion 84 houses the clutch spring 25 (see FIG. 1). The spring housing portion 84 is arranged side by side with the pressure side assist cam surface 90A with respect to the rotation direction S. Note that the term "side by side" does not require the spring housing portion 84 and the pressure side assist cam surface 90A to be adjacent to each other. The spring housing portion 84 and the pressure side assist cam surface 90A may be separated from each other with respect to the rotation direction S, or other elements (e.g., recesses, etc.) integral with the pressure side cam portion 90 may be provided between the spring housing portion 84 and the pressure side assist cam surface 90A with respect to the rotation direction S. The spring housing portion 84 is arranged between the pressure side assist cam surface 90A and the pressure side slipper cam surface 90S with respect to the rotation direction S. As shown in FIG. 1, a first holding groove 115 that is recessed from the second direction D2 toward the first direction D1 is formed in the spring housing portion 84. The first holding groove 115 holds an end portion 25A of the clutch spring 25 in the first direction D1, which will be described later. The first holding groove 115 fixes the end portion 25A in the first direction D1 to the pressure plate 70. The first holding groove 115 is formed in a circular shape when viewed from the direction D. The inner diameter of the first holding groove 115 is the same as or smaller than the outer diameter of the clutch spring 25. By fitting the end portion 25A of the clutch spring 25 in the first direction D1 into the first holding groove 115, the first holding groove 115 fixes the end portion 25A in the first direction D1 to the pressure plate 70. Note that as long as the first holding groove 115 can suppress the end portion 25A in the first direction D1 from relatively moving in the rotation direction S with respect to the pressure plate 70, the first holding groove 115 does not have to be formed in a circular shape when viewed from the direction D (that is, there may be a gap in a part between the inner peripheral surface of the first holding groove 115 and the outer peripheral surface of the clutch spring 25). The first holding groove 115 may be formed, for example, in an elliptical shape or the like when viewed from the direction D.

[0042] As shown in FIGS. 1 and 9, the clutch spring 25 is accommodated in the spring accommodation 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, formed in a cylindrical shape. The end portion 25A of the clutch spring 25 in the first direction D1 is in contact with the pressure plate 70. The end portion 25B of the clutch spring 25 in the second direction D2 is in contact with the stopper plate 100. As shown in FIGS. 10A and 10B, from the state where the center side assist cam surface 60A and the pressure side assist cam surface 90A are separated in the rotational direction S (see FIG. 10A) until they approach and contact each other (see FIG. 10B), the axis 25L of the clutch spring 25 is inclined in the direction from the pressure side assist cam surface 90A toward the clutch spring 25 (i.e., the second rotational direction S2) as it goes from the first direction D1 to the second direction D2 (see FIG. 10B), or is parallel to a straight line extending in the direction D which is the direction in which the pressure plate 70 moves (see FIG. 10A). According to such an aspect, when shifting from the state where the clutch is disengaged (see FIG. 10A) to the state where the clutch is engaged (see FIG. 10B), a restoring force in the direction from the clutch spring 25 toward the pressure side assist cam surface 90A (i.e., the first rotational direction S1) does not occur in the clutch spring 25. The axis 25L of the clutch spring 25 may be inclined in the direction from the pressure side assist cam surface 90A toward the clutch spring 25 (i.e., the second rotational direction S2) as it goes from the first direction D1 to the second direction D2 over the entire state from the state of FIG. 10A to the state of FIG. 10B. That is, in the example shown in FIG. 10A, the axis 25L of the clutch spring 25 is parallel to the straight line extending in the direction D in the state where the clutch is disengaged, but may be inclined in the direction from the pressure side assist cam surface 90A toward the clutch spring 25 (i.e., the second rotational direction S2) as it goes from the first direction D1 to the second direction D2.

[0043] As shown in FIG. 1, the stopper plate 100 is provided so as to be able to contact the pressure plate 70. Note that the stopper plate 100 may be provided so as to be able to contact a member that is movable in the direction D in conjunction with the pressure plate 70. The stopper plate 100 is a member that suppresses the pressure plate 70 from separating from the clutch center 40 by a predetermined distance or more in the second direction D2. 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 bolts 28. The stopper plate 100 is fastened and fixed to the boss portion 54 of the clutch center 40 via the bolts 28 with the clutch spring 25 accommodated in the spring accommodation portion 84. The stopper plate 100 is formed in a ring shape in plan view. A second holding groove 120 that is recessed from the first direction D1 toward the second direction D2 is formed in the stopper plate 100. The second holding groove 120 holds the end portion 25B of the clutch spring 25 in the second direction D2. The second holding groove 120 fixes the end portion 25B in the second direction D2 to the stopper plate 100. The second holding groove 120 is formed in a circular shape when viewed from the direction D. The inner diameter of the second holding groove 120 is the same as or smaller than the outer diameter of the clutch spring 25. By fitting the end portion 25B of the clutch spring 25 in the second direction D2 into the second holding groove 120, the second holding groove 120 fixes the end portion 25B in the second direction D2 to the pressure plate 70. Note that as long as the second holding groove 120 can suppress the end portion 25B in the second direction D2 from moving relatively in the rotational direction S with respect to the pressure plate 70, the second holding groove 120 may not be formed in a circular shape when viewed from the direction D (that is, there may be a gap in a part between the inner peripheral surface of the second holding groove 120 and the outer peripheral surface of the clutch spring 25). The second holding groove 120 may be formed, for example, in an elliptical shape or the like when viewed from the direction D.

[0044] As shown in FIG. 1, the reduction means 110 of the present embodiment includes a first holding groove 115 and a second holding groove 120. As shown in FIGS. 10A and 10B, the reduction means 110 reduces the restoring force in the direction from the clutch spring 25 toward the pressure-side assist cam surface 90A (i.e., the first rotation direction S1) in the clutch spring 25 from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S (see FIG. 10A) until they approach and contact each other (see FIG. 10B). In the present embodiment, the reduction means 110 reduces the restoring force in the direction from the clutch spring 25 toward the pressure-side assist cam surface 90A (i.e., the first rotation direction S1) in the clutch spring 25 from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S (see FIG. 10A) until they approach and contact each other (see FIG. 10B) by the first holding groove 115 and the second holding groove 120.

[0045] As shown in FIGS. 10A and 10B, the reducing means 110 suppresses (e.g., regulates) the relative movement of the end 25A of the clutch spring 25 in the first direction D1 in the rotational direction S with respect to the pressure plate 70 and the relative movement of the end 25B of the clutch spring 25 in the second direction D2 in the rotational direction S with respect to the stopper plate 100 from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotational direction S (see FIG. 10A) until they approach and contact each other (see FIG. 10B). In the present embodiment, the reducing means 110 suppresses (e.g., regulates) the relative movement of the end 25A of the clutch spring 25 in the first direction D1 in the rotational direction S with respect to the pressure plate 70 and the relative movement of the end 25B of the clutch spring 25 in the second direction D2 in the rotational direction S with respect to the stopper plate 100 from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotational direction S (see FIG. 10A) until they approach and contact each other (see FIG. 10B) by the first holding groove 115 and the second holding groove 120. Note that the reducing means 110 slightly allows the relative movement of the end 25A of the clutch spring 25 in the first direction D1 in the rotational direction S with respect to the pressure plate 70 and the relative movement of the end 25B of the clutch spring 25 in the second direction D2 in the rotational direction S with respect to the stopper plate 100 as long as the restoring force can be reduced.

[0046] As shown in FIGS. 10A and 10B, the reducing means 110 fixes the end 25A of the clutch spring in the first direction D1 to the pressure plate 70 and fixes the end 25B of the clutch spring 25 in the second direction D2 to the stopper plate 100. In the present embodiment, the reducing means 110 fixes the end 25A of the clutch spring 25 in the first direction D1 to the pressure plate 70 by the first holding groove 115 and fixes the end 25B of the clutch spring 25 in the second direction D2 to the stopper plate 100 by the second holding groove 120.

[0047] Next, the operation of the clutch device 10 of the present embodiment will be described. As described above, the clutch device 10 is disposed between the engine and the transmission of the motorcycle, and when the driver performs a clutch operation (for example, operating an operation lever or pressing an operation button), the rotational driving force of the engine is transmitted to and cut off from the transmission.

[0048] When the driver of the motorcycle does not perform a clutch operation, the clutch release mechanism (not shown) of the clutch device 10 does not press the push rod 16A, so the pressure plate 70 presses the input-side rotating plate 20 by the biasing force (elastic force) of the clutch spring 25. As a result, the clutch center 40 is in a state where the input-side rotating plate 20 and the output-side rotating plate 22 are pressed against each other and frictionally connected (that is, the clutch is connected) and rotates driven. Thereby, the rotational driving force of the engine is transmitted to the clutch center 40 and the output shaft 15 rotates driven.

[0049] On the other hand, when the driver of the motorcycle performs a clutch operation while the clutch device 10 is in a state where the clutch is connected, the clutch release mechanism (not shown) presses the push rod 16A, so the pressure plate 70 moves in a direction away from the clutch center 40 (the second direction D2) against the biasing force of the clutch spring 25. As a result, the clutch center 40 is in a state where the frictional connection between the input-side rotating plate 20 and the output-side rotating plate 22 is released (that is, the clutch is disengaged), so that the rotational driving of the output shaft 15 is attenuated or the rotational driving stops. Thereby, the rotational driving force of the engine is cut off from the clutch center 40. Note that until the state where the clutch is connected (see FIG. 10B) shifts to the state where the clutch is disengaged (see FIG. 10A), the reduction means 110 reduces the restoring force in the direction from the clutch spring 25 toward the pressure-side assist cam surface 90A (that is, the first rotational direction S1) in the clutch spring 25. Here, the above restoring force does not occur in the clutch spring 25.

[0050] And when the driver releases the clutch operation (for example, releases the operation of the operation lever or releases the pressing of the operation button) in the state where the clutch is disengaged (see FIG. 10A), the pressing of the pressure plate 70 via the push member 16B by the clutch release mechanism (not shown) is released. Therefore, the pressure plate 70 is displaced in the direction (the first direction D1) approaching the clutch center 40 by the biasing force of the clutch spring 25. From the state where the clutch is disengaged (see FIG. 10A) to the state where it is engaged (see FIG. 10B), the reducing means 110 reduces the restoring force in the direction from the clutch spring 25 toward the pressure-side assist cam surface 90A (that is, the first rotational direction S1) in the clutch spring 25. Here, the above restoring force does not occur in the clutch spring 25. For this reason, it is suppressed that the center-side assist cam surface 60A and the pressure-side assist cam surface 90A come into sudden contact with each other.

[0051] As described above, according to the clutch device 10 of the present embodiment, the reducing means 110 reduces the restoring force in the direction from the clutch spring 25 toward the pressure-side assist cam surface 90A (that is, the first rotational direction S1) in the clutch spring 25 until the center-side assist cam surface 60A and the pressure-side assist cam surface 90A approach and contact each other while being separated in the rotational direction S. In this way, since the restoring force that can be generated in the clutch spring 25 is reduced by the reducing means 110, it is suppressed that the center-side assist cam surface 60A and the pressure-side assist cam surface 90A come into sudden contact with each other due to the restoring force. That is, the reducing means 110 can suppress the clutch from suddenly engaging.

[0052] In the clutch device 10 of the present embodiment, during the period from when the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated from each other in the rotational direction S until they approach and contact each other, the end portion 25A of the clutch spring 25 in the first direction D1 relatively moves in the rotational direction S with respect to the pressure plate 70, and the end portion 25B of the clutch spring 25 in the second direction D2 relatively moves in the rotational direction S with respect to the stopper plate 100 are suppressed. During the period from when the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated from each other in the rotational direction S until they approach and contact each other, the axis 25L of the clutch spring 25 is inclined in the direction from the first direction D1 to the second direction D2 toward the clutch spring 25 from the pressure-side assist cam surface 90A (that is, the second rotational direction S2), or is parallel to a straight line extending in the direction D which is the direction in which the pressure plate 70 moves. According to the above aspect, a restoring force in the direction from the clutch spring 25 toward the pressure-side assist cam surface 90A does not occur in the clutch spring 25.

[0053] In the clutch device 10 of the present embodiment, the reduction means 110 fixes the end portion 25A of the clutch spring 25 in the first direction D1 to the pressure plate 70 and fixes the end portion 25B of the clutch spring 25 in the second direction D2 to the stopper plate 100. According to the above aspect, the movement of the clutch spring 25 with respect to the pressure plate 70 and the stopper plate 100 can be more reliably suppressed. Thereby, a restoring force in the direction from the clutch spring 25 toward the pressure-side assist cam surface 90A does not occur in the clutch spring 25.

[0054] In the clutch device of the present embodiment, the reduction means 110 is formed in the pressure plate 70, recessed from the second direction D2 toward the first direction D1, and holds the end portion D1 of the clutch spring 25 in the first direction D1. The reduction means 110 includes a first holding groove 115. The reduction means 110 is also formed in the stopper plate 100, recessed from the first direction D1 toward the second direction D2, and holds the end portion 25B of the clutch spring 25 in the second direction D2. The reduction means 110 includes a second holding groove 120. According to the above aspect, the clutch spring 25 can be more easily fixed to the pressure plate 70 and the stopper plate 100.

[0055] <Second Embodiment> FIGS. 11A and 11B are cross-sectional views showing a part of the clutch device 210 according to the second embodiment. The clutch device 210 includes an output shaft 15, an input-side rotating plate 20, an output-side rotating plate 22, a clutch housing 30, a clutch center 40, a pressure plate 270, a stopper plate 300, a clutch spring 225, and a reduction means 310.

[0056] As shown in FIGS. 11A and 12, the pressure plate 270 includes a spring housing portion 284 that houses the clutch spring 225. The spring housing portion 284 is an example of a housing portion. The spring housing portion 284 is formed in the pressure-side cam portion 90. The spring housing portion 284 is formed to be recessed from the second direction D2 toward the first direction D1. The spring housing portion 284 is partitioned by a partition wall 284W. The spring housing portion 284 is formed in a circular shape when viewed in the direction D (see also FIG. 12). The spring housing portion 284 is formed such that the inner diameter increases as it goes from the first direction D1 to the second direction D2. The spring housing portion 284 is arranged side by side with the pressure-side assist cam surface 90A with respect to the rotation direction S. Note that "side by side" does not necessarily mean that the spring housing portion 284 and the pressure-side assist cam surface 90A are adjacent to each other. The spring housing portion 284 and the pressure-side assist cam surface 90A may be separated from each other with respect to the rotation direction S, or another element (for example, a recess or the like) integral with the pressure-side cam portion 90 may be provided between the spring housing portion 284 and the pressure-side assist cam surface 90A with respect to the rotation direction S. The spring housing portion 2"84 is arranged between the pressure-side assist cam surface 90A and the pressure-side slipper cam surface 90S with respect to the rotation direction S.

[0057] As shown in FIGS. 11A and 12, the clutch spring 225 is accommodated in the spring housing portion 284. The clutch spring 225 is in contact with the inner peripheral surface 284P of the partition wall 284W over the entire partition wall 284W (i.e., over the entire direction D of the partition wall 284W). The clutch spring 225 is, for example, a conical spring formed by spirally winding spring steel. The clutch spring 225 is formed in a frustum shape, for example, such that the outer diameter increases from the first direction D1 to the second direction D2. The clutch spring 225 biases the pressure plate 270 toward the clutch center 40. That is, the clutch spring 225 biases the pressure plate 270 in the first direction D1. The end portion 225A of the clutch spring 225 in the first direction D1 is in contact with the pressure plate 270. The end portion 225A in the first direction D1 is provided so as not to be slidable with respect to the pressure plate 270. The end portion 225B of the clutch spring 225 in the second direction D2 is in contact with the stopper plate 300. The end portion 225B in the second direction D2 is provided so as to be slidable with respect to the stopper plate 300. As shown in FIGS. 11A and 11B, from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotational direction S (see FIG. 11A) to the state where they approach and contact each other (see FIG. 11B), the axis 225L of the clutch spring 225 is parallel to a straight line extending in the direction D, which is the direction in which the pressure plate 270 moves. That is, the clutch spring 225 does not tilt. According to such an aspect, a restoring force in the direction from the clutch spring 225 toward the pressure-side assist cam surface 90A (i.e., the first rotational direction S1) does not occur in the clutch spring 225. Note that FIG. 11A shows the state where the clutch is disengaged, and FIG. 11B shows the state where the clutch is engaged.

[0058] As shown in FIG. 11A, the stopper plate 300 has the same configuration as the stopper plate 100 except that the second holding groove 120 (see FIG. 10A) is not formed.

[0059] As shown in FIG. 11A, the reduction means 310 of the present embodiment is the partition wall 284W that partitions the spring housing portion 284. As shown in FIGS. 11A and 11B, the reduction means 310 reduces the restoring force in the direction from the clutch spring 225 toward the pressure-side assist cam surface 90A (i.e., the first rotation direction S1) of the clutch spring 225 from a state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S (see FIG. 11A) until they approach and contact each other (see FIG. 11B). In the present embodiment, the reduction means 310 suppresses the inclination of the clutch spring 225 accommodated in the spring housing portion 284 in the rotation direction S from a state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S (see FIG. 11A) until they approach and contact each other (see FIG. 11B). In the present embodiment, from a state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S (see FIG. 11A) until they approach and contact each other (see FIG. 11B), the clutch spring 225 is in contact with the inner peripheral surface 284P of the partition wall 284W over the entire partition wall 284W (i.e., over the entire direction D of the partition wall 284W). For this reason, the clutch spring 225 does not tilt, and the restoring force in the direction from the clutch spring 225 toward the pressure-side assist cam surface 90A (i.e., the first rotation direction S1) in the clutch spring 225 is not generated.

[0060] In the clutch device 210 of the present embodiment, the reduction means 310 suppresses the inclination of the clutch spring 225 accommodated in the spring housing portion 284 in the rotation direction S from a state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S until they approach and contact each other. According to the above aspect, since the inclination of the clutch spring 225 in the rotation direction S is suppressed by the reduction means 310, the restoring force in the direction from the clutch spring 225 toward the pressure-side assist cam surface 90A in the clutch spring 225 is not generated.

[0061] In the clutch device 210 of the present embodiment, the reduction means 310 is the partition wall 284W that partitions the spring accommodation portion 284, and the clutch spring 225 is in contact with the inner peripheral surface 284P of the partition wall 284W over the entire partition wall 284W. According to the above aspect, since the clutch spring 225 does not tilt in the rotational direction S, no restoring force in the direction from the clutch spring 225 toward the pressure-side assist cam surface 90A is generated in the clutch spring 225.

[0062] In the clutch device 210 of the present embodiment, the spring accommodation portion 284 is formed such that the inner diameter increases from the first direction D1 to the second direction D2, and the clutch spring 225 is formed in a frustum shape. According to the above aspect, since the clutch spring 225 does not tilt in the rotational direction S, no restoring force in the direction from the clutch spring 225 toward the pressure-side assist cam surface 90A is generated in the clutch spring 225.

[0063] <Third Embodiment> FIG. 13 is a cross-sectional view of a clutch device 410 according to the third embodiment. As shown in FIG. 13, the clutch device 410 includes an output shaft 15, an input-side rotating plate 20, an output-side rotating plate 22, a clutch housing 30, a clutch center 440, a pressure plate 470, a lifter plate 500, a clutch spring 25, and a reduction means 510. The clutch device 410 is a so-called externally disengaged type clutch device.

[0064] As shown in FIG. 13, the side wall 33 of the clutch housing 30 extends in the first direction D1 from the edge of the bottom wall 31.

[0065] As shown in FIG. 13, the pressure plate 470 includes a plurality (three in this embodiment) of boss portions 554. The boss portion 554 is a member that supports the lifter plate 500. The plurality of boss portions 554 are arranged at equal intervals in the rotational direction S. The boss portion 554 is formed in a cylindrical shape. The boss portion 554 extends toward the clutch center 440 (i.e., in the first direction D1). The boss portion 554 is provided on the pressure-side cam portion 90. As shown in FIGS. 14A and 14B, the boss portion 554 is located between the pressure-side assist cam surface 90A and the pressure-side slipper cam surface 90S with respect to the rotational direction S. A screw hole 554H is formed in the boss portion 554. The screw hole 554H extends in the axial direction of the pressure plate 470. A bolt 28 (see FIG. 13) used to fix the lifter plate 500 to the pressure plate 470 is inserted into the screw hole 554H.

[0066] As shown in FIG. 13, the clutch center 440 includes a spring housing portion 484. The spring housing portion 484 is an example of a housing portion. The spring housing portion 484 is formed in the main body 42. The spring housing portion 484 is formed in the center side cam portion 60. The spring housing portion 484 is formed to be recessed from the first direction D1 toward the second direction D2. The spring housing portion 484 is formed in an elliptical shape when viewed from the direction D. The spring housing portion 484 houses the clutch spring 25. As shown in FIGS. 14A and 14B, the spring housing portion 484 is arranged side by side with the center side assist cam surface 60A with respect to the rotation direction S. Note that "side by side" does not necessarily mean that the spring housing portion 484 and the center side assist cam surface 60A are adjacent to each other, and the spring housing portion 484 and the center side assist cam surface 60A may be separated from each other with respect to the rotation direction S, or other elements (for example, recesses, etc.) integral with the center side cam portion 60 may be provided between the spring housing portion 484 and the center side assist cam surface 60A with respect to the rotation direction S. The spring housing portion 484 is arranged between the center side assist cam surface 60A and the center side slipper cam surface 60S with respect to the rotation direction S. A first holding groove 515 that is recessed from the first direction D1 toward the second direction D2 is formed in the spring housing portion 484. The first holding groove 515 holds the end portion 25B of the clutch spring 25 in the second direction D2. The first holding groove 515 fixes the end portion 25B in the second direction D2 to the clutch center 440. The first holding groove 515 has the same configuration as the first holding groove 115.

[0067] As shown in FIG. 13, the clutch spring 25 is accommodated in the spring accommodating portion 484. The end portion 25B of the clutch spring 25 in the second direction D2 is in contact with the clutch center 440. The end portion 25A of the clutch spring 25 in the first direction D1 is in contact with the lifter plate 500. As shown in FIGS. 14A and 14B, from the state where the center side assist cam surface 60A and the pressure side assist cam surface 90A are separated in the rotation direction S (see FIG. 14A) to the state where they approach and contact each other (see FIG. 14B), the axis 25L of the clutch spring 25 is inclined in the direction from the center side assist cam surface 60A toward the clutch spring 25 (i.e., the first rotation direction S1) as it goes from the second direction D2 to the first direction D1 (see FIG. 14B), or is parallel to a straight line extending in the direction D which is the direction in which the pressure plate 470 moves (see FIG. 14A). According to such an aspect, when shifting from the state where the clutch is disengaged (see FIG. 14A) to the state where the clutch is engaged (see FIG. 14B), no restoring force in the direction from the clutch spring 25 toward the center side assist cam surface 60A (i.e., the second rotation direction S2) is generated in the clutch spring 25. The axis 25L of the clutch spring 25 may be inclined in the direction from the center side assist cam surface 60A toward the clutch spring 25 (i.e., the first rotation direction S1) as it goes from the second direction D2 to the first direction D1 over the entire state from the state of FIG. 14A to the state of FIG. 14B.

[0068] As shown in FIG. 13, the lifter plate 500 is provided so as to be in contact with the clutch center 40. Note that the lifter plate 500 may be provided so as to be in contact with a member that is rotatable in conjunction with the clutch center 400. The lifter plate 500 is a member for displacing the pressure plate 470 in the direction D. The lifter plate 500 is a member that suppresses the pressure plate 70 from being separated from the clutch center 40 by a predetermined distance or more in the second direction D2. The lifter plate 500 is fixed to the pressure plate 470. The lifter plate 500 is fixed to the boss portion 554 of the pressure plate 470 by bolts 28. The lifter plate 500 rotates integrally with the pressure plate 470. The lifter plate 500 moves in the direction D with respect to the clutch center 440 and rotates relative to the clutch center 440. The lifter plate 500 is formed in a disc shape. A release bearing 503 is provided on the lifter plate 500. The release bearing 503 is a member that is pressed by a release fork 512 of a clutch release mechanism (not shown). Here, the clutch release mechanism is a mechanical device that presses the release bearing 503 toward the output shaft 15 side (i.e., the second direction D2 side) via the release fork 512 by an operation of a clutch operation lever (not shown) of a driver in a vehicle such as a motorcycle equipped with the clutch device 410. The lifter plate 500 supports the clutch spring 25 housed in the spring housing portion 484 of the clutch center 440. An insertion hole 504H into which the bolts 28 for fixing the lifter plate 500 to the pressure plate 470 are inserted is formed in the lifter plate 500. A second holding groove 520 that is recessed from the second direction D2 toward the first direction D1 is formed in the lifter plate 500. The second holding groove 520 holds the end portion 25A of the clutch spring 25 in the first direction D1. The second holding groove 520 fixes the end portion 25A in the first direction D1 to the lifter plate 500. The second holding groove 520 has the same configuration as the second holding groove 120.

[0069] As shown in FIG. 13, the reduction means 510 of the present embodiment includes a first holding groove 515 and a second holding groove 520. As shown in FIGS. 14A and 14B, the reduction means 510 reduces the restoring force in the direction from the clutch spring 25 toward the center-side assist cam surface 60A (i.e., the second rotation direction S2) in the clutch spring 25 from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S (see FIG. 14A) until they approach and contact each other (see FIG. 14B). In the present embodiment, the reduction means 510 reduces the restoring force in the direction from the clutch spring 25 toward the center-side assist cam surface 60A (i.e., the second rotation direction S2) in the clutch spring 25 from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S (see FIG. 14A) until they approach and contact each other (see FIG. 14B) by the first holding groove 515 and the second holding groove 520.

[0070] As shown in FIGS. 14A and 14B, the reduction means 510 suppresses the relative movement of the end portion 25B of the clutch spring 25 in the second direction D2 in the rotational direction S with respect to the clutch center 440 and the relative movement of the end portion 25A of the clutch spring 25 in the first direction D1 in the rotational direction S with respect to the lifter plate 500 from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotational direction S (see FIG. 14A) until they approach and contact each other (see FIG. 14B). In the present embodiment, the reduction means 510, by the first holding groove 515 and the second holding groove 520, suppresses the relative movement of the end portion 25B of the clutch spring 25 in the second direction D2 in the rotational direction S with respect to the clutch center 440 and the relative movement of the end portion 25A of the clutch spring 25 in the first direction D1 in the rotational direction S with respect to the lifter plate 500 from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotational direction S (see FIG. 14A) until they approach and contact each other (see FIG. 14B). Note that the reduction means 510 slightly allows the relative movement of the end portion 25B in the second direction D2 in the rotational direction S with respect to the clutch center 440 and the relative movement of the end portion 25A in the first direction D1 in the rotational direction S with respect to the lifter plate 500 as long as the reduction means 510 can reduce the above-described restoring force.

[0071] As shown in FIGS. 14A and 14B, the reduction means 510 fixes the end portion 25B of the clutch spring 25 in the second direction D2 to the clutch center 440 and fixes the end portion 25A of the clutch spring 25 in the first direction D1 to the lifter plate 500. In the present embodiment, the reduction means 510 fixes the end portion 25B of the clutch spring 25 in the second direction D2 to the clutch center 440 by the first holding groove 515 and fixes the end portion 25A of the clutch spring 25 in the first direction D1 to the lifter plate 500 by the second holding groove 520.

[0072] As described above, according to the clutch device 410 of the present embodiment, the reducing means 510 reduces the restoring force in the direction from the clutch spring 25 toward the center side assist cam surface 60A (i.e., the second rotation direction S2) in the clutch spring 25 until the center side assist cam surface 60A and the pressure side assist cam surface 90A come close to and contact each other in the rotation direction S. In this way, since the restoring force that can be generated in the clutch spring 25 is reduced by the reducing means 510, it is possible to suppress the sudden contact between the center side assist cam surface 60A and the pressure side assist cam surface 90A due to the restoring force. That is, it is possible to suppress the sudden connection of the clutch by the reducing means 510.

[0073] In the clutch device 410 of the present embodiment, the reducing means 510 suppresses the relative movement of the end portion 25B of the clutch spring 25 in the second direction D2 in the rotation direction S with respect to the clutch center 440 and the relative movement of the end portion 25A of the clutch spring 25 in the first direction D1 in the rotation direction S with respect to the lifter plate 500 until the center side assist cam surface 60A and the pressure side assist cam surface 90A come close to and contact each other in the rotation direction S. Until the center side assist cam surface 60A and the pressure side assist cam surface 90A come close to and contact each other in the rotation direction S, the axis 25L of the clutch spring 25 inclines in the direction from the second direction D2 to the first direction D1 in the direction from the center side assist cam surface 60A toward the clutch spring 25 (i.e., the first rotation direction S1), or is parallel to a straight line extending in the direction D which is the direction in which the pressure plate 70 moves. According to the above aspect, no restoring force in the direction from the clutch spring 25 toward the center side assist cam surface 60A is generated in the clutch spring 25.

[0074] <Fourth Embodiment> FIG. 15A and FIG. 15B are cross-sectional views showing a part of the clutch device 610 according to the fourth embodiment. The clutch device 610 includes an output shaft 15, an input-side rotating plate 20, an output-side rotating plate 22, a clutch housing 30, a clutch center 540, a pressure plate 470, a lifter plate 600, a clutch spring 225, and a reducing means 710.

[0075] As shown in FIGS. 15A and 15B, the clutch center 540 includes a spring housing portion 584 that houses the clutch spring 225. The spring housing portion 584 is an example of a housing portion. The spring housing portion 584 is formed in the center-side cam portion 60. The spring housing portion 584 is formed to be recessed from the first direction D1 toward the second direction D2. The spring housing portion 584 is partitioned by a partition wall 584W. The spring housing portion 584 is formed in a circular shape when viewed in the direction D. The spring housing portion 584 is formed such that the inner diameter increases as it goes from the second direction D2 to the first direction D1. The spring housing portion 584 is arranged side by side with the center-side assist cam surface 60A with respect to the rotation direction S. Note that "side by side" does not necessarily mean that the spring housing portion 584 and the center-side assist cam surface 60A are adjacent to each other. The spring housing portion 584 and the center-side assist cam surface 60A may be separated from each other with respect to the rotation direction S, or other elements (for example, recesses, etc.) integral with the center-side cam portion 60 may be provided between the spring housing portion 584 and the center-side assist cam surface 60A with respect to the rotation direction S. The spring housing portion 584 is arranged between the center-side assist cam surface 60A and the center-side slipper cam surface 60S with respect to the rotation direction S.

[0076] As shown in FIGS. 15A and 15B, the clutch spring 225 is accommodated in the spring housing portion 584. The clutch spring 225 is in contact with the inner peripheral surface 584P of the partition wall 584W over the entire partition wall 584W (i.e., over the entire direction D of the partition wall 584W). The clutch spring 225 biases the pressure plate 470 toward the clutch center 540. That is, the clutch spring 225 biases the pressure plate 470 in the first direction D1. The end portion 225B of the clutch spring 225 in the second direction D2 is in contact with the clutch center 540. The end portion 225B in the second direction D2 is provided so as not to be slidable with respect to the clutch center 540. The end portion 225A of the clutch spring 225 in the first direction D1 is in contact with the lifter plate 600. The end portion 225A in the first direction D1 is provided so as to be slidable with respect to the lifter plate 600. From the state where the center side assist cam surface 60A and the pressure side assist cam surface 90A are separated from each other in the rotational direction S (see FIG. 15A) until they approach and contact each other (see FIG. 15B), the axis 225L of the clutch spring 225 is parallel to a straight line extending in the direction D in which the pressure plate 270 moves. That is, the clutch spring 225 does not tilt. According to such an aspect, no restoring force is generated in the clutch spring 225 in the direction from the clutch spring 225 toward the center side assist cam surface 60A (i.e., the second rotational direction S2). Note that FIG. 15A shows a state where the clutch is disengaged, and FIG. 15B shows a state where the clutch is engaged.

[0077] As shown in FIG. 15A, the lifter plate 600 has the same configuration as the lifter plate 500 except that the second holding groove 520 (see FIG. 14A) is not formed.

[0078] As shown in FIG. 15A, the reduction means 710 of the present embodiment is a partition wall 584W that partitions the spring housing portion 584. As shown in FIGS. 15A and 15B, the reduction means 710 reduces the restoring force in the direction from the clutch spring 225 toward the center-side assist cam surface 60A (i.e., the second rotation direction S2) in the clutch spring 225 from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S (see FIG. 15A) until they approach and contact each other (see FIG. 15B). In the present embodiment, the reduction means 710 suppresses the inclination of the clutch spring 225 accommodated in the spring housing portion 584 in the rotation direction S from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S (see FIG. 15A) until they approach and contact each other (see FIG. 15B). In the present embodiment, from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S (see FIG. 15A) until they approach and contact each other (see FIG. 15B), the clutch spring 225 is in contact with the inner peripheral surface 584P of the partition wall 584W over the entire partition wall 584W (i.e., over the entire direction D of the partition wall 584W). For this reason, the clutch spring 225 does not tilt, and the restoring force in the direction from the clutch spring 225 toward the center-side assist cam surface 60A (i.e., the second rotation direction S2) does not occur in the clutch spring 225.

[0079] In the clutch device 610 of the present embodiment, the reduction means 710 suppresses the inclination of the clutch spring 225 accommodated in the spring housing portion 584 in the rotation direction S from the state where the center-side assist cam surface 60A and the pressure-side assist cam surface 90A are separated in the rotation direction S until they approach and contact each other. According to the above aspect, since the inclination of the clutch spring 225 in the rotation direction S is suppressed by the reduction means 710, the restoring force in the direction from the clutch spring 225 toward the center-side assist cam surface 60A does not occur in the clutch spring 225.

[0080] In the clutch device 610 of the present embodiment, the reduction means 710 is the partition wall 584W that partitions the spring housing portion 584, and the clutch spring 225 is in contact with the inner peripheral surface 584P of the partition wall 584W over the entire partition wall 584W. According to the above aspect, since the clutch spring 225 does not tilt in the rotational direction S, a restoring force in the direction from the clutch spring 225 toward the center side assist cam surface 60A does not occur in the clutch spring 225.

[0081] As described above, the preferred embodiments of the present invention have been described. However, the above-described embodiments are merely examples, and the present invention can be implemented in various other forms.

[0082] In the above-described first embodiment, the end portion 25A of the clutch spring 25 in the first direction D1 is fixed to the pressure plate 70 by the first holding groove 115, but the fixing method is not limited to this. For example, the end portion 25A in the first direction D1 may be fixed by attaching it to the pressure plate 70, a member with high friction may be arranged at the contact portion between the pressure plate 70 and the end portion 25A in the first direction D1 to fix them to each other, or the end portion 25A in the first direction D1 may be fixed to the pressure plate 70 by a protrusion or the like. The end portion 25B of the clutch spring 25 in the second direction D2 may also be fixed by the same method. Also, in the third embodiment, the fixing method for fixing the end portion 25B of the clutch spring 25 in the second direction D2 to the clutch center 440 and the fixing method for fixing the end portion 25A of the clutch spring 25 in the first direction D1 to the lifter plate 500 may be the same method.

[0083] In the above-described second embodiment, the clutch spring 225 suppressed the inclination of the clutch spring 225 by contacting the inner peripheral surface 284P of the partition wall 284W over the entire partition wall 284W, but the present invention is not limited thereto. For example, the inclination of the clutch spring 225 may be suppressed by a protrusion or the like protruding from the inner peripheral surface 284P of the partition wall 284W toward the clutch spring 225. Further, in the fourth embodiment, for example, the inclination of the clutch spring 225 may be suppressed by a protrusion or the like protruding from the inner peripheral surface 584P of the partition wall 584W toward the clutch spring 225.

[0084] In the above-described second embodiment, the clutch spring 225 suppressed the inclination of the clutch spring 225 by contacting the inner peripheral surface 284P of the partition wall 284W over the entire partition wall 284W. However, as long as the restoring force can be reduced, a slight gap may be provided between the outer peripheral surface of the clutch spring 225 and the inner peripheral surface of the partition wall 284W over the entire partition wall 284W or partially. The same applies to the fourth embodiment.

[0085] In the first to fourth embodiments described above, the clutch centers 40, 440, 540 held the output-side rotating plate 22, but the clutch centers 40, 440, 540 do not necessarily have to hold the output-side rotating plate 22. That is, all the output-side rotating plates 22 may be held by the pressure plates 70, 270, 470, and the clutch centers 40, 440, 540 do not have to hold even a single output-side rotating plate 22.

Explanation of Signs

[0086] 10 Clutch device 15 Output shaft 20 Input-side rotating plate 22 Output-side rotating plate 25 Clutch spring 25A End portion in the first direction 25B End portion in the second direction 25L Axis 40 Clutch center 54 boss part 60 center side cam part 60A center side assist cam surface 60S center side slipper cam surface 70 pressure plate 84 spring housing part (housing part) 90 pressure side cam part 90A pressure side assist cam surface 90S pressure side slipper cam surface 100 stopper plate 110 reduction means 115 first holding groove 120 second holding groove

Claims

1. A clutch device that transmits or blocks the rotational driving force of an input shaft to an output shaft, accommodated in a clutch housing that holds a plurality of input-side rotating plates that are rotationally driven by the rotational driving of the input shaft, and a clutch center that is rotationally driven together with the output shaft, provided so as to be able to approach or separate from and relatively rotate with respect to the clutch center, and holding at least one of a plurality of output-side rotating plates arranged alternately with the input-side rotating plates, and a pressure plate capable of pressing the input-side rotating plates and the output-side rotating plates, a clutch spring that biases the pressure plate in the first direction when the direction in which the pressure plate approaches the clutch center is defined as the first direction and the direction in which the pressure plate separates from the clutch center is defined as the second direction, a stopper plate fixed to the clutch center and suppressing the pressure plate from separating from the clutch center by a predetermined distance or more in the second direction, the end of the clutch spring in the first direction contacts the pressure plate, and the end of the clutch spring in the second direction contacts the stopper plate, the clutch center has a plurality of center-side cam portions having a center-side assist cam surface that generates a force in the direction from the pressure plate toward the clutch center to increase the pressing force between the input-side rotating plate and the output-side rotating plate when relatively rotating with respect to the pressure plate, and a center-side slipper cam surface that separates the pressure plate from the clutch center to decrease the pressing force between the input-side rotating plate and the output-side rotating plate, the pressure plate has a plurality of pressure-side cam portions having a pressure-side assist cam surface that is configured to be able to contact the center-side assist cam surface and generates a force in the direction from the pressure plate toward the clutch center to increase the pressing force between the input-side rotating plate and the output-side rotating plate when relatively rotating with respect to the clutch center, and a pressure-side slipper cam surface that separates the pressure plate from the clutch center to decrease the pressing force between the input-side rotating plate and the output-side rotating plate, It is arranged side by side with the presser-side assist cam surface with respect to the rotation direction of the pressure plate, and has a housing portion for housing the clutch spring. It is formed in the housing portion and has a first fixing portion that suppresses the movement in the rotation direction of the end portion of the clutch spring in the first direction. The stopper plate is formed with a second fixing portion that suppresses the movement in the rotation direction of the end portion of the clutch spring in the second direction. When the direction from the presser-side slipper cam surface to the presser-side assist cam surface of one of the presser-side cam portions with respect to the rotation direction is defined as the first rotation direction, and the direction from the presser-side assist cam surface to the presser-side slipper cam surface of one of the presser-side cam portions is defined as the second rotation direction, the pressure plate and the clutch center are configured to rotate in the first rotation direction. A clutch device in which a part of the end portion of the clutch spring on the second fixing portion side is located on the second rotation direction side rather than the end portion of the clutch spring on the first fixing portion side in a state where the center-side assist cam surface and the presser-side assist cam surface are in contact with each other in a cross-sectional view along the circumferential direction of the clutch center and the pressure plate.

2. In the cross-sectional view along the circumferential direction of the clutch center and the pressure plate, in a state where the center-side slipper cam surface and the presser-side slipper cam surface are in contact with each other, the end portion of the first fixing portion on the first rotation direction side and the end portion of the second fixing portion on the first rotation direction side are at the same position with respect to the rotation direction, and the end portion of the first fixing portion on the second rotation direction side and the end portion of the second fixing portion on the second rotation direction side are at the same position. The clutch device according to claim 1.

3. The first fixing portion is a first holding groove that is formed so as to be recessed from the second direction to the first direction and fixes the end portion of the clutch spring in the first direction. The second fixing portion is a second holding groove that is formed so as to be recessed from the first direction to the second direction and fixes the end portion of the clutch spring in the second direction. The clutch device according to claim 1.

4. A clutch device that transmits or shuts off the rotational driving force of an input shaft to an output shaft. It is housed 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 a clutch center that is rotationally driven together with the output shaft, At least one of a plurality of output-side rotating plates that are provided so as to be able to approach or separate from and rotate relative to the clutch center, and are alternately arranged with the input-side rotating plates, and hold the input-side rotating plates and the output-side rotating plates A pressure plate capable of pressing, When the first direction is the direction in which the pressure plate approaches the clutch center and the second direction is the direction in which the pressure plate separates from the clutch center, a clutch spring that biases the pressure plate in the first direction, A lifter plate that is fixed to the pressure plate and suppresses the pressure plate from separating from the clutch center by a predetermined distance or more in the second direction, The end portion of the clutch spring in the first direction contacts the lifter plate, and the end portion of the clutch spring in the second direction contacts the clutch center, The clutch center is, When rotating relative to the pressure plate, a center-side assist cam surface that generates a force in the direction from the pressure plate toward the clutch center to increase the pressing force between the input-side rotating plate and the output-side rotating plate, and the input-side rotating plate and the output-side rotating plate And a plurality of center-side cam portions having a center-side slipper cam surface for separating the pressure plate from the clutch center in order to reduce the pressing force of the output-side rotating plate, An accommodating portion that is arranged side by side with the center-side assist cam surface with respect to the rotation direction of the clutch center and accommodates the clutch spring, A first fixing portion that is formed in the accommodating portion and suppresses the movement of the end portion of the clutch spring in the second direction in the rotation direction, The pressure plate is, When rotating relative to the clutch center, a pressure plate side assist cam surface that is configured to be contactable with the center side assist cam surface and generates a force in a direction from the pressure plate toward the clutch center to increase the pressing force between the input side rotating plate and the output side rotating plate, and a plurality of pressure plate side cam portions having a pressure plate side slipper cam surface for separating the pressure plate from the clutch center to reduce the pressing force between the input side rotating plate and the output side rotating plate. On the lifter plate, a second fixing portion is formed to suppress the movement in the rotational direction of the end portion of the clutch spring in the first direction. When the direction from the pressure plate side slipper cam surface to the pressure plate side assist cam surface of one of the pressure plate side cam portions with respect to the rotational direction is defined as the first rotational direction, and the direction from the pressure plate side assist cam surface to the pressure plate side slipper cam surface of one of the pressure plate side cam portions is defined as the second rotational direction, the pressure plate and the clutch center are configured to rotate in the first rotational direction. A part of the end portion of the clutch spring on the second fixing portion side is located on the first rotational direction side of the end portion of the clutch spring on the first fixing portion side in a cross-sectional view along the circumferential direction of the clutch center and the pressure plate when the center side assist cam surface and the pressure plate side assist cam surface are in contact, a clutch device.

5. In a cross-sectional view along the circumferential direction of the clutch center and the pressure plate, when the center side slipper cam surface and the pressure plate side slipper cam surface are in contact, the end portion of the first fixing portion on the first rotational direction side and the end portion of the second fixing portion on the first rotational direction side are at the same position with respect to the rotational direction, and the end portion of the first fixing portion on the second rotational direction side and the end portion of the second fixing portion on the second rotational direction side are at the same position, the clutch device according to claim 4.

6. The first fixing portion is formed to be recessed from the first direction to the second direction, and is a first holding groove for fixing the end portion of the clutch spring in the second direction. The clutch device according to claim 4, wherein the second fixing portion is formed to be recessed from the second direction toward the first direction, and is a second holding groove that fixes an end portion of the clutch spring in the first direction.

Images