Clutch device

Abstract

To further efficiently supply clutch oil to an output-side rotating plate and an input-side rotating plate.SOLUTION: A clutch device 10 comprises: a clutch center 40 having a plurality of center-side fitting teeth 47 for holding an output-side rotating plate 22; and a pressure plate 70 having a plurality of pressure-side fitting teeth 77 for holding the output-side rotating plate 22, and capable of pressing the input-side rotating plate 20 and the output-side rotating plate 22. The pressure-side fitting teeth 77 are located outside the center-side fitting teeth 47 in a radial direction, end parts 77T of the pressure-side fitting teeth 77 in a first direction D1 are located at the first direction D1 side rather than end parts 47T of the center-side fitting teeth 47 in a second direction D2, a part of the pressure-side fitting teeth 77 is at least partially overlapped on the center-side fitting teeth 47 in the radial direction, and the other part of the pressure-side fitting teeth 77 is not at least partially overlapped on the center-side fitting teeth 47.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a clutch device, and more particularly to a clutch device that selectively transmits or cuts off the rotational driving force of an input shaft, which is rotationally driven by a prime mover such as an engine, to an output shaft. [Background technology]

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

[0003] For example, Patent Document 1 discloses a clutch device that includes a clutch center (clutch member) that holds an output side rotating plate (driven side clutch plate) and a pressure plate (pressure member) that is provided so as to be able to approach and separate from the clutch center. The pressure plate is configured so as to be able to press the input side rotating plate and the output side rotating plate. In this way, the clutch center and the pressure plate are assembled together and used in the clutch device.

[0004] In the clutch device of Patent Document 1, the clutch center has center-side fitting teeth (an outer peripheral wall on which a spline is formed) and the pressure plate has pressure-side fitting teeth as portions for holding the output-side rotating plate. When the clutch center and the pressure plate are assembled, the center-side fitting teeth and the pressure-side fitting teeth are configured to overlap in the radial direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent No. 6903020 Summary of the Invention [Problem to be solved by the invention]

[0006] However, oil that has flowed out from the inside of the clutch center to the outside tends to accumulate in the area where the center-side mating teeth and the pressure-side mating teeth overlap in the radial direction. It is desirable for the clutch oil to be supplied in a balanced manner to the entire output-side rotating plate held by the clutch center and the pressure plate, and the input-side rotating plate located between the output-side rotating plates.

[0007] The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to provide a clutch device that can more effectively supply clutch oil to the output side rotating plate and the input side rotating plate. [Means for solving the problem]

[0008] The clutch device according to the present invention is a clutch device for transmitting or interrupting the rotational driving force of an input shaft to an output shaft, and includes a clutch housing for holding a plurality of input side rotating plates that are rotationally driven by the rotational driving of the input shaft, a clutch center housed in the clutch housing, holding a plurality of output side rotating plates arranged alternately with the input side rotating plates, and rotating 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 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, an outer peripheral wall located radially outward from the output shaft holding portion, a plurality of center side fitting teeth that hold the output side rotating plates and are formed so as to protrude radially outward from the outer peripheral surface of the outer peripheral wall, and a plurality of spline grooves formed between adjacent center side fitting teeth. The pressure plate holds the output side rotating plate and includes a plurality of pressure side fitting teeth that are circumferentially arranged. The pressure-side fitting teeth are located radially outward of the center-side fitting teeth. When a direction in which the pressure plate approaches the clutch center is defined as a first direction and a direction in which the pressure plate moves away from the clutch center is defined as a second direction, an end of the pressure-side fitting teeth in the first direction is located closer to the first direction than an end of the center-side fitting teeth in the second direction. Of the multiple pressure-side fitting teeth, some of the pressure-side fitting teeth at least partially overlap with the center-side fitting teeth in the radial direction, and other of the pressure-side fitting teeth at least partially do not overlap with the center-side fitting teeth in the radial direction.

[0009] According to the clutch device of the present invention, the clutch oil flowing out from the output shaft or the like is discharged to the outside of the clutch center through the oil discharge hole or the like. Here, since the input side rotating plate and the output side rotating plate are held outside the clutch center, when the pressure plate and the clutch center are rotating, a part of the clutch oil is supplied to the input side rotating plate and the output side rotating plate. Furthermore, the pressure side fitting teeth are located radially outward from the center side fitting teeth. And, the end of the pressure side fitting teeth in the first direction is located on the first direction side from the end of the center side fitting teeth in the second direction. Here, among the multiple pressure side fitting teeth, some of the pressure side fitting teeth at least partially overlap with the center side fitting teeth in the radial direction. Therefore, in that part, even when the pressure plate and the clutch center are rotating, a part of the clutch oil does not scatter to the outside and the clutch oil can be retained. As a result, the clutch oil can be supplied little by little to the output side rotating plate and the input side rotating plate near the pressure plate. On the other hand, among the multiple pressure side fitting teeth, some of the pressure side fitting teeth do not overlap at least partially with the center side fitting teeth in the radial direction. Therefore, in that portion, when the pressure plate and the clutch center rotate, the clutch oil is scattered to the outside, so that the clutch oil can be immediately supplied to the output side rotating plate and the input side rotating plate. Effect of the Invention

[0010] According to the present invention, it is possible to provide a clutch device capable of more effectively supplying clutch oil to the output side rotating plate and the input side rotating plate. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view of a clutch device according to one embodiment. [Diagram 2] FIG. 2 is a perspective view of the clutch center according to one embodiment. [Diagram 3] FIG. 3 is a plan view of the clutch center according to one embodiment. [Figure 4]FIG. 4 is a perspective view of a pressure plate according to one embodiment. [Diagram 5] FIG. 5 is a plan view of a pressure plate according to one embodiment. [Figure 6] FIG. 6 is a perspective view of a pressure plate according to one embodiment. [Figure 7] FIG. 7 is a plan view of a pressure plate according to one embodiment. [Figure 8] FIG. 8 is an enlarged side view of a part of the pressure-side cam portion according to one embodiment. [Figure 9] FIG. 9 is an enlarged perspective view of a portion of a pressure plate according to one embodiment. [Figure 10] FIG. 10 is a plan view showing a state in which the clutch center and the pressure plate according to one embodiment are combined. [Figure 11A] FIG. 11A is a schematic diagram for explaining the action of the center side assist cam surface and the pressure side assist cam surface. [Figure 11B] FIG. 11B is a schematic diagram for explaining the action of the center-side slipper cam surface and the pressure-side slipper cam surface. [Figure 12] FIG. 12 is a cross-sectional view of a clutch center and a pressure plate according to one embodiment. [Figure 13] FIG. 13 is a side view of the clutch center and the pressure plate according to one embodiment. [Figure 14] FIG. 14 is a side view of the clutch center and the pressure plate when the pressure-side slipper cam surface and the center-side slipper cam surface are in contact with each other. [Figure 15] FIG. 15 is a side view of the clutch center and pressure plate when the pressure-side slipper cam surface and the center-side slipper cam surface are not in contact and the pressure-side assist cam surface and the center-side assist cam surface are not in contact. [Figure 16] FIG. 16 is a side view of the clutch center and the pressure plate when the pressure-side assist cam surface and the center-side assist cam surface come into contact with each other. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of a clutch device according to the present invention will be described with reference to the drawings. Note that the embodiment described here is not intended to limit the present invention in any particular way. In addition, the same reference numerals are used for members and parts that perform the same functions, and duplicated descriptions will be omitted or simplified as appropriate.

[0013] 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 the motorcycle to an output shaft 15. The clutch device 10 is a device that transmits or cuts off the rotational driving force of the input shaft to a driving wheel (rear wheel) via the output shaft 15. The clutch device 10 is disposed between the engine and the transmission.

[0014] In the following description, the direction in which the pressure plate 70 and the clutch center 40 of the clutch device 10 are aligned is defined as direction D, the direction in which the pressure plate 70 approaches the clutch center 40 is defined as a first direction D1, and the direction in which the pressure plate 70 moves away from the clutch center 40 is defined as a second direction D2. The circumferential direction of the clutch center 40 and the pressure plate 70 is defined as 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 defined as a first circumferential direction S1 (see FIG. 5), and the direction from the other pressure side cam portion 90 to one pressure side cam portion 90 is defined as a second circumferential direction S2 (see FIG. 5). In this embodiment, the axial direction of the output shaft 15, the axial direction of the clutch housing 30, the axial direction of the clutch center 40, and the axial direction of the pressure plate 70 are the same as direction D. Furthermore, the pressure plate 70 and the clutch center 40 rotate in a first circumferential direction S1. However, the above direction is merely a direction 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.

[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, and a stopper plate 100.

[0016] As shown in Fig. 1, the output shaft 15 is a shaft body formed into a hollow shape. One end of the output shaft 15 rotatably supports an input gear 35 and a clutch housing 30 (described later) via a needle bearing 15A. The output shaft 15 fixedly supports a clutch center 40 via a nut 15B. That is, the output shaft 15 rotates integrally with the clutch center 40. The other end of the output shaft 15 is connected to, for example, a transmission (not shown) of a motorcycle.

[0017] As shown in FIG. 1, the output shaft 15 includes a push rod 16A in a hollow portion 15H thereof 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 slidably 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 have a smaller inner diameter than the inner diameter of the hollow portion 15H, ensuring the flow of clutch oil within the hollow portion 15H.

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

[0019] As shown in Fig. 1, an input gear 35 is provided on a 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 is rotated 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 circumferential surface of a 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.

[0021] The input side rotating plate 20 is a member pressed against the output side rotating plate 22. The input side rotating plate 20 is a flat plate formed in an annular shape. The input side rotating plate 20 is formed by punching out a thin plate made of SPCC (cold rolled steel plate) material into an annular shape. Friction materials (not shown) made of multiple pieces of paper are 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.

[0022] As shown in Fig. 1, the clutch center 40 is accommodated in the clutch housing 30. The clutch center 40 is disposed concentrically with the clutch housing 30. The clutch center 40 has a cylindrical main body 42 and a flange 68 extending radially outward from the outer circumferential edge of the main body 42. The clutch center 40 holds an input side rotating plate 20 and a plurality of output side rotating plates 22 arranged alternately in direction D. The clutch center 40 is a member that is rotated 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 outward of the base wall 43 and extending toward the second direction D2, an output shaft holding portion 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.

[0024] The output shaft holding portion 50 is formed in a cylindrical shape. An insertion hole 51 into which the output shaft 15 is inserted and spline-fitted is formed in the output shaft holding portion 50. The insertion hole 51 is formed penetrating the base wall 43. An inner circumferential surface 50A of the output shaft holding portion 50 that forms the insertion hole 51 has a plurality of spline grooves formed along the axial direction. The output shaft 15 is connected to the output shaft holding portion 50.

[0025] 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 number of the center side fitting teeth 47 may be a multiple of the number of the center side cam portions 60. In this embodiment, as described later, the number of the center side cam portions 60 is three, and the number of the center side fitting teeth 47 is 30. The number of the center side fitting teeth 47 does not have to be a multiple of the number of the center side cam portions 60. As shown in FIG. 3, the center side fitting teeth 47 include a pair of side surfaces 47P extending in the radial direction and a top surface 47Q connecting the radially outer ends of the pair of side surfaces 47P. The side surfaces 47P are an example of a first side surface. The top surface 47Q is an example of a first top surface. The top surface 47Q extends in the circumferential direction S. The oil discharge hole 49 is formed penetrating the outer peripheral wall 45 in the radial direction. The oil discharge hole 49 is formed between the adjacent center side fitting teeth 47. That is, the oil discharge hole 49 is formed in the spline groove 48. The oil discharge hole 49 is formed on the side of the center side cam portion 60. The oil discharge hole 49 is formed on the side of the center side slipper cam surface 60S of the center side cam portion 60. The oil discharge hole 49 is formed on the second circumferential direction S2 side of the center side slipper cam surface 60S. The oil discharge hole 49 is formed on the first circumferential direction S1 side of a boss portion 54 described later. In this embodiment, the oil discharge holes 49 are formed in threes at three locations in the circumferential direction S of the outer peripheral wall 45. The oil discharge holes 49 are arranged at positions equally spaced apart in the circumferential direction S. The oil discharge holes 49 communicate between the inside and the outside of the clutch center 40.The oil drain hole 49 is a hole for draining 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 .

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

[0027] 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 out 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 for holding clutch oil. The front and back surfaces of the output side rotating plate 22 are each subjected to a surface hardening treatment in order 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.

[0028] The center cam portion 60 is formed in a platform shape having a cam surface made of an inclined surface constituting 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 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 cam portions 60 are disposed at equal intervals in the circumferential direction S of the clutch center 40. In this embodiment, the clutch center 40 has three center cam portions 60, but the number of center 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 a direction that moves the pressure plate 70 closer to the clutch center 40 in order to increase the pressing force (pressing force) between the input side rotating plate 20 and the output side rotating plate 22 when the center-side assist cam surface 60A rotates 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 disposed opposite each other in the circumferential direction S.

[0030] As shown in FIG. 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 disposed 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 are formed with a screw hole 54H into which the bolt 28 (see FIG. 1) is inserted. The screw hole 54H extends in the axial direction of the clutch center 40.

[0031] As shown in FIG. 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 a 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 appropriately set according to the amount of clutch oil to be circulated, and is, for example, not less than 0.1 mm and not more than 0.5 mm.

[0032] 2 and 3, the clutch center 40 has a center-side cam hole 43H penetrating 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 with each other.

[0033] 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 relatively 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 circumferential 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 that are arranged alternately with the input side rotating plate 20.

[0034] 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 accommodating portion 84 (see also FIG. 6).

[0035] 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 a 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.

[0036] The pressure-side cam portion 90 is formed in a platform shape having a cam surface made of an inclined surface constituting an Assist & Slipper (registered trademark) mechanism that slides on 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 a 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.

[0037] As shown in FIG. 5, the pressure-side cam portion 90 is located radially outside 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) and a pressure-side slipper cam surface 90S. The pressure-side assist cam surface 90A is configured to be able to come into contact with the center-side assist cam surface 60A. The pressure-side assist cam surface 90A is configured to generate a force in a direction that moves the pressure plate 70 closer to the clutch center 40 in order to increase the pressing force (pressing 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 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 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 disposed opposite each other in the circumferential direction S.

[0038] As shown in Fig. 8, a chamfered portion 90AP is formed by linearly chamfering an end portion 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 an end portion 90AB in the first circumferential direction S1 of the pressure-side assist cam surface 90A.

[0039] Here, the action of the center side cam portion 60 and the pressure side cam portion 90 will be described. When the engine speed increases and the rotational driving force input to the input gear 35 and the clutch housing 30 can be transmitted to the output shaft 15 via the clutch center 40, a rotational force in the first circumferential direction S1 is applied to the pressure plate 70 as shown in Fig. 11A. Therefore, a force in the first direction D1 is generated on the pressure plate 70 due to the action of the center side assist cam surface 60A and the pressure side assist cam surface 90A. This increases the pressing force between the input side rotating plate 20 and the output side rotating plate 22.

[0040] On the other hand, when the rotation speed of the output shaft 15 exceeds the rotation speed of the input gear 35 and the clutch housing 30 and back torque is generated, a rotational force in the first circumferential direction S1 is applied to the clutch center 40 as shown in Fig. 11B. 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 to release 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.

[0041] 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).

[0042] As shown in Figs. 4 and 5, the pressure plate 70 has a pressure-side cam hole 73H penetrating a part of the main body 72 and 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 Figs. 5 and 7, when viewed from the axial direction of the pressure plate 70, the pressure-side assist cam surface 90A and a part of the pressure-side cam hole 73H overlap each other.

[0043] As shown in FIG. 4, the pressure plate 70 includes a plurality of pressure side fitting teeth 77 arranged on a flange 98, and a plurality of through-holes 78 formed in the flange 98. The pressure side fitting teeth 77 hold the output side rotating plate 22. The pressure side fitting teeth 77 protrude from the flange 98 in a first direction D1. The pressure side fitting teeth 77 are located radially outward from the cylindrical portion 80. The pressure side fitting teeth 77 are located radially outward from the pressure side cam portion 90. The pressure side fitting teeth 77 are located radially outward from the pressure side fitting portion 88. The pressure side fitting teeth 77 are aligned in the circumferential direction S. The pressure side fitting teeth 77 are arranged at equal intervals in the circumferential direction S. As shown in FIG. 5, the pressure side fitting tooth 77 has a pair of side surfaces 77P extending in the radial direction and a top surface 77Q connecting the radially outer ends of the pair of side surfaces 77P. The side surfaces 77P are an example of a second side surface. The top surface 77Q is an example of a second top surface. The top surface 77Q extends in the circumferential direction S. Note that in this embodiment, some of the pressure side fitting teeth 77 are removed, so the intervals between the removed portions are wider, but the other adjacent pressure side fitting teeth 77 are arranged at equal intervals. The through portions 78 are formed between the adjacent pressure side fitting teeth 77. The through portions 78 penetrate in the radial direction. The through portions 78 open in the radial direction and the first direction D1.

[0044] As shown in FIG. 12, the pressure side fitting teeth 77 are located radially outward of the center side fitting teeth 47 so as to be spaced apart from the center side fitting teeth 47 in the radial direction of the output shaft 15. A gap is formed between the pressure side fitting teeth 77 and the center side fitting teeth 47 in the radial direction. As shown in FIG. 13, when the center side assist cam surface 60A and the pressure side assist cam surface 90A contact each other, the end 77T of the pressure side fitting teeth 77 in the first direction D1 is located closer to the first direction D1 than the end 47T of the center side fitting teeth 47 in the second direction D2. Note that FIGS. 12 to 16 are diagrams showing the relationship between the clutch center and the pressure plate, and for convenience of explanation, the input side rotating plate 20 and the output side rotating plate 22 are omitted from the drawings. In addition, the overlap state between the pressure side engaging teeth 77 and the center side engaging teeth 47 described later is the same when the input side rotating plate 20 and the output side rotating plate 22 are attached to the clutch center 40 and the pressure plate 70, and when the input side rotating plate 20 and the output side rotating plate 22 are not attached to the clutch center 40 and the pressure plate 70.

[0045] 12, when the clutch device 10 is in a normal state (i.e., when the pressure-side assist cam surface 90A and the center-side assist cam surface 60A are in contact with each other), some of the pressure-side fitting teeth 77 at least partially overlap with the center-side fitting teeth 47 when viewed from the radial direction of the output shaft 15. Here, the pressure-side fitting teeth 77 and the center-side fitting teeth 47 overlap when viewed from the radial direction of the output shaft 15 means, for example, that the top surface 77Q of the pressure-side fitting tooth 77 and the top surface 47Q of the center-side fitting tooth 47 overlap when viewed from the radial direction of the output shaft 15. Further, the pressure side fitting teeth 77 at least partially overlap with the center side fitting teeth 47 when viewed from the radial direction of the output shaft 15 means that 50% to 100%, preferably 60% to 100%, of the area of ​​the top face 77Q of the pressure side fitting teeth 77 overlaps with the top face 47Q of the center side fitting teeth 47. Further, of the multiple pressure side fitting teeth 77, some of the pressure side fitting teeth 77 overlap with the center side fitting teeth 47 by more than half of the length of the pressure side fitting teeth 77 in the circumferential direction S when viewed from the radial direction of the output shaft 15. In this embodiment, the length of the top face 47Q in the circumferential direction S is longer than the length of the top face 77Q in the circumferential direction S. For example, the pressure-side fitting tooth 77A, which is one of the pressure-side fitting teeth 77, overlaps with the center-side fitting tooth 47A over the entire length in the circumferential direction S of the pressure-side fitting tooth 77A when viewed from the radial direction of the output shaft 15. Furthermore, in the normal state of the clutch device 10, at least a portion of at least one through-portion 78A of the multiple through-portions 78 overlaps with the center-side fitting tooth 47 when viewed from the radial direction of the output shaft 15. Furthermore, in the normal state of the clutch device 10, at least a portion of a top surface 77Q of a part of the pressure-side fitting tooth 77 out of the multiple pressure-side fitting teeth 77 overlaps with the top surface 47Q of the center-side fitting tooth 47 when viewed from the radial direction of the output shaft 15.

[0046] 12, in the normal state of the clutch device 10, some of the pressure side fitting teeth 77 do not at least partially overlap with the center side fitting teeth 47 when viewed from the radial direction of the output shaft 15. Here, the pressure side fitting teeth 77 and the center side fitting teeth 47 do not overlap when viewed from the radial direction of the output shaft 15 means, for example, that the top surface 77Q of the pressure side fitting teeth 77 and the top surface 47Q of the center side fitting teeth 47 do not overlap when viewed from the radial direction of the output shaft 15. In addition, the pressure side fitting teeth 77 do not at least partially overlap with the center side fitting teeth 47 when viewed from the radial direction of the output shaft 15 means that 50% to 100%, preferably 60% to 100%, of the area of ​​the top surface 77Q of the pressure side fitting teeth 77 does not overlap with the top surface 47Q of the center side fitting teeth 47. Further, among the multiple pressure side fitting teeth 77, some other pressure side fitting teeth 77 do not overlap with the center side fitting teeth 47 over a portion of half or more of the length in the circumferential direction S of the pressure side fitting teeth 77 when viewed from the radial direction of the output shaft 15. For example, the pressure side fitting tooth 77B, which is one of the pressure side fitting teeth 77, does not overlap with the center side fitting teeth 47B and the center side fitting teeth 47C over a portion of half or more of the length in the circumferential direction S of the pressure side fitting teeth 77B when viewed from the radial direction of the output shaft 15. Further, in the normal state of the clutch device 10, the top surface 77Q of some other pressure side fitting teeth 77 among the multiple pressure side fitting teeth 77 does not overlap at least a portion with the top surface 47Q of the center side fitting tooth 47 when viewed from the radial direction of the output shaft 15.

[0047] As shown in FIG. 14, when the pressure side slipper cam surface 90S and the center side slipper cam surface 60S are in contact with each other, some of the pressure side fitting teeth 77 (e.g., the top surfaces 77Q of the pressure side fitting teeth 77) among the multiple pressure side fitting teeth 77 at least partially overlap with the center side fitting teeth 47 (e.g., the top surfaces 47Q of the center side fitting teeth 47) when viewed from the radial direction of the output shaft 15, and some of the other pressure side fitting teeth 77 (e.g., the top surfaces 77Q of the pressure side fitting teeth 77) do not at least partially overlap with the center side fitting teeth 47 (e.g., the top surfaces 47Q of the center side fitting teeth 47) when viewed from the radial direction of the output shaft 15. In addition, in a state where the pressure-side slipper cam surface 90S and the center-side slipper cam surface 60S are in contact with each other, at least one of the through-holes 78A among the plurality of through-holes 78 at least partially overlaps with the center-side fitting tooth 47 when viewed from the radial direction of the output shaft 15. In addition, in a state where the pressure-side slipper cam surface 90S and the center-side slipper cam surface 60S are in contact with each other, among the plurality of pressure-side fitting teeth 77, the top surfaces 77Q of some of the pressure-side fitting teeth 77 at least partially overlap with the top surfaces 47Q of the center-side fitting teeth 47 when viewed from the radial direction of the output shaft 15, and the top surfaces 77Q of the other pressure-side fitting teeth 77 do not at least partially overlap with the top surfaces 47Q of the center-side fitting teeth 47 when viewed from the radial direction of the output shaft 15.

[0048] When the pressure plate 70 approaches the clutch center 40 by a predetermined distance from the state shown in Figure 14, the pressure side slipper cam surface 90S and the center side slipper cam surface 60S do not come into contact, and the pressure side assist cam surface 90A and the center side assist cam surface 60A do not come into contact (see Figure 15). As shown in FIG. 15, when the pressure side slipper cam surface 90S and the center side slipper cam surface 60S are not in contact and the pressure side assist cam surface 90A and the center side assist cam surface 60A are not in contact, some of the pressure side fitting teeth 77 (e.g., the top surface 77Q of the pressure side fitting teeth 77) among the multiple pressure side fitting teeth 77 at least partially overlap with the center side fitting teeth 47 (e.g., the top surface 47Q of the center side fitting teeth 47) when viewed from the radial direction of the output shaft 15, and some of the other pressure side fitting teeth 77 (e.g., the top surface 77Q of the pressure side fitting teeth 77) among the multiple pressure side fitting teeth 77 do not at least partially overlap with the center side fitting teeth 47 (e.g., the top surface 47Q of the center side fitting teeth 47) when viewed from the radial direction of the output shaft 15. Furthermore, when the pressure side slipper cam surface 90S and the center side slipper cam surface 60S are not in contact and the pressure side assist cam surface 90A and the center side assist cam surface 60A are not in contact, at least one of the multiple through portions 78A overlaps at least partially with the center side engaging tooth 47 when viewed from the radial direction of the output shaft 15. In addition, when the pressure side slipper cam surface 90S and the center side slipper cam surface 60S are not in contact and the pressure side assist cam surface 90A and the center side assist cam surface 60A are not in contact, the top surfaces 77Q of some of the pressure side fitting teeth 77 among the multiple pressure side fitting teeth 77 at least partially overlap with the top surfaces 47Q of the center side fitting teeth 47 when viewed from the radial direction of the output shaft 15, and the top surfaces 77Q of the other pressure side fitting teeth 77 do not at least partially overlap with the top surfaces 47Q of the center side fitting teeth 47 when viewed from the radial direction of the output shaft 15.

[0049] When the pressure plate 70 approaches the clutch center 40 by a predetermined distance from the state shown in FIG. 15, the pressure-side assist cam surface 90A and the center-side assist cam surface 60A come into contact with each other (see FIG. 16). As shown in FIG. 16, when the pressure side assist cam surface 90A and the center side assist cam surface 60A are in contact (i.e., under normal conditions), some of the pressure side fitting teeth 77 (e.g., top surfaces 77Q of the pressure side fitting teeth 77) among the multiple pressure side fitting teeth 77 at least partially overlap with the center side fitting teeth 47 (e.g., top surfaces 47Q of the center side fitting teeth 47) when viewed from the radial direction of the output shaft 15, and some of the other pressure side fitting teeth 77 (e.g., top surfaces 77Q of the pressure side fitting teeth 77) do not at least partially overlap with the center side fitting teeth 47 (e.g., top surfaces 47Q of the center side fitting teeth 47) when viewed from the radial direction of the output shaft 15.

[0050] 12, in the normal state of the clutch device 10, the spline groove 48 in which the oil discharge hole 49 is formed does not overlap at least a part with the pressure side fitting tooth 77 when viewed from the radial direction of the output shaft 15. Here, the spline groove 48 in which the oil discharge hole 49 is formed and the pressure side fitting tooth 77 do not overlap when viewed from the radial direction of the output shaft 15 means, for example, that a part of the top surface 77Q of the pressure side fitting tooth 77 and a part of the outer peripheral surface 45S of the outer peripheral wall 45 in which the oil discharge hole 49 is formed do not overlap when viewed from the radial direction of the output shaft 15. In addition, the spline groove 48 does not overlap at least a part with the pressure side fitting tooth 77 when viewed from the radial direction of the output shaft 15 means that 50% to 100%, preferably 60% to 100%, of the area of ​​the top surface 77Q of the pressure side fitting tooth 77 does not overlap with the outer peripheral surface 45S of the outer peripheral wall 45. As shown in FIGS. 12 and 14, for example, the spline groove 48A does not overlap with the pressure side fitting teeth 77C and the pressure side fitting teeth 77D by 60% when viewed from the radial direction of the output shaft 15.

[0051] As shown in Figs. 6 and 7, the spring accommodating portion 84 is formed in the pressure-side cam portion 90. The spring accommodating portion 84 is 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 Fig. 1). An insertion hole 84H into which the boss portion 54 (see Fig. 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.

[0052] 1, the pressure spring 25 is accommodated in the spring accommodating portion 84. The pressure spring 25 is held by the boss portion 54 inserted into the insertion hole 84H of the spring accommodating portion 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 formed by winding spring steel in a spiral shape.

[0053] FIG. 10 is a plan view showing a state in which the clutch center 40 and the pressure plate 70 are assembled. In the state shown in FIG. 10, the pressure side assist cam surface 90A and the center side assist cam surface 60A are not in contact with each other, and the pressure side slipper cam surface 90S and the center side slipper cam surface 60S are not in contact with each other. At this time, the pressure plate 70 is closest to the clutch center 40. This state is defined as the normal state of the clutch device 10. As shown in FIG. 10, the distance L5 in the circumferential direction S between the boss portion 54 and the end 84HA of the insertion hole 84H on the pressure side assist cam surface 90A side (i.e., the first circumferential direction S1 side) in the normal state is shorter than the distance L6 in the circumferential direction S between the boss portion 54 and the end 84HB of the insertion hole 84H on the pressure side slipper cam surface 90S side (i.e., the second circumferential direction S2 side) in the normal state.

[0054] 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 in the second direction D2 by more than a predetermined distance. 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 in a state in which the boss portion 54 of the clutch center 40 and the pressure spring 25 are arranged in the spring accommodating portion 84. The stopper plate 100 is formed in a substantially triangular shape in a plan view.

[0055] 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, respectively. Also, when the pressure plate 70 contacts the stopper plate 100, the pressure spring 25 is separated from the side wall of the spring accommodating portion 84. That is, the pressure spring 25 is not sandwiched between the boss portion 54 and the spring accommodating portion 84, and excessive stress is prevented from being applied to the boss portion 54.

[0056] Here, the circumferential length L1 (see Figure 5) 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 of 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 circumferential length L2 (see Figure 3) 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.

[0057] Furthermore, when viewed from the axial direction of the output shaft 15, the angle θ1 (see Figure 5) formed by 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 of the pressure side cam portions 90 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 Figure 3) formed by 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 the center 80C and end 90AB of the cylindrical portion 80 and a line passing through the center 80C and end 90SB. Angle θ2 is the angle between a line passing through the center 50C and end 60AB of the output shaft holding portion 50 and a line passing through the center 50C and end 60SB.

[0058] In addition, the length L3 (see Figure 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 Figure 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.

[0059] Also, as viewed from the axial direction of the output shaft 15, an 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 center 54C of the boss portion 54 is larger than an 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 an 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 center 54C of the boss portion 54. The angle θ4 is an angle between a straight line passing through the center 80C and the end 90AB of the cylindrical portion 80 and a straight line passing through the center 80C and the center 84HC of the insertion hole 84H.

[0060] As shown in FIG. 12 , when viewed from the axial direction of the output shaft 15 (i.e., direction D), a straight line passing through the center 80C of the cylindrical portion 80 (i.e., center 15C of the output shaft 15) and an end 77SA on the first circumferential direction S1 side of one pressure-side fitting tooth 77E of the pressure-side fitting teeth 77 adjacent to the center 80C of the cylindrical portion 80 in the circumferential direction S, and an end 77SA on the second circumferential direction S2 side of the other pressure-side fitting tooth 77F of the pressure-side fitting teeth 77 adjacent to the center 80C of the cylindrical portion 80 are aligned along a line extending from the center 80C of the cylindrical portion 80 to the end 77SA on the second circumferential direction S2 side of the other pressure-side fitting tooth 77F of the pressure-side fitting teeth 77 adjacent to the center 80C of the cylindrical portion 80. The smallest angle θ5 among the angles formed with the line passing through the center 50C of the output shaft holding portion 50 and the end 47SA on the first circumferential direction S1 side of one center-side fitting tooth 47D of the center-side fitting teeth 47 adjacent to each other in the circumferential direction S is larger than an angle θ6 formed with a line passing through the center 50C of the output shaft holding portion 50 and the end 47SB on the second circumferential direction S2 side of the other center-side fitting tooth 47E of the center-side fitting teeth 47 adjacent to each other in the circumferential direction S. Note that the angle θ5 may be smaller than the angle θ6. In this embodiment, since some of the pressure side fitting teeth 77 have been removed, for example, the angle θ7 between a straight line passing through the center 80C of the tubular portion 80 and the end portion 77SA on the first circumferential direction S1 side of one pressure side fitting tooth 77G of the adjacent pressure side fitting teeth 77 in the circumferential direction S, and a straight line passing through the center 80C of the tubular portion 80 and the end portion 77SB on the second circumferential direction S2 side of the other pressure side fitting tooth 77H of the adjacent pressure side fitting teeth 77 in the circumferential direction S, is larger than θ5 and θ6.

[0061] A predetermined amount of clutch oil is filled inside the clutch device 10. 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 suppresses wear of the friction material. The clutch device 10 of this embodiment is a so-called wet-type multi-plate friction clutch device.

[0062] 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 transmits or cuts off the rotational driving force of the engine to the transmission when the rider operates the clutch operating lever.

[0063] In the clutch device 10, 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 is driven to rotate. That is, the rotational driving force of the engine is transmitted to the clutch center 40, and the output shaft 15 is driven to rotate.

[0064] In the clutch ON state, the clutch oil that flows inside the hollow portion H of the output shaft 15 and flows out from the tip end 15T of the output shaft 15 drops or flies into the cylindrical portion 80 and adheres thereto (see arrow F in FIG. 1). The clutch oil that adheres to the inside of the cylindrical portion 80 is guided into the clutch center 40. As a result, the clutch oil flows out to the outside of the clutch center 40 through the oil discharge hole 49. The clutch oil also flows out to the outside 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 to the outside of the clutch center 40 is then supplied to the input side rotating plate 20 and the output side rotating plate 22.

[0065] On the other hand, when the rider of the motorcycle operates the clutch operating lever in the clutch ON state, the clutch release mechanism (not shown) presses the push rod 16A, and the pressure plate 70 is displaced 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.

[0066] 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 led 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 of the clutch center 40 more actively and flows to various places inside the clutch device 10. In particular, the clutch oil can be actively led between the input side rotating plate 20 and the output side rotating plate 22, which are separated from each other.

[0067] 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 force of the pressure spring 25.

[0068] As described above, according to the clutch device 10 of this embodiment, the clutch oil flowing out from the output shaft 15, etc. is discharged to the outside of the clutch center 40 through the oil discharge hole 49, etc. Here, since the input side rotating plate 20 and the output side rotating plate 22 are held outside the clutch center 40, when the pressure plate 70 and the clutch center 40 are rotating, a part of the clutch oil is supplied to the input side rotating plate 20 and the output side rotating plate 22. Furthermore, the pressure side fitting teeth 77 are located radially outward from the center side fitting teeth 47. And, the end 77T of the pressure side fitting teeth 77 in the first direction D1 is located on the first direction D1 side from the end 47T of the center side fitting teeth 47 in the second direction D2. Here, among the multiple pressure side fitting teeth 77, some of the pressure side fitting teeth 77 at least partially overlap with the center side fitting teeth 47 in the radial direction. Therefore, in this portion, even when the pressure plate 70 and the clutch center 40 are rotating, a part of the clutch oil does not scatter to the outside, and the clutch oil can be retained. This allows the clutch oil to be supplied little by little to the output side rotating plate 22 and the input side rotating plate 20 near the pressure plate 70. Meanwhile, among the multiple pressure side fitting teeth 77, some of the other pressure side fitting teeth 77 do not overlap at least partially with the center side fitting teeth 47 in the radial direction. Therefore, in this portion, when the pressure plate 70 and the clutch center 40 rotate, the clutch oil scatters to the outside, and therefore the clutch oil can be immediately supplied to the output side rotating plate 22 and the input side rotating plate 20.

[0069] In the clutch device 10 of this embodiment, among the multiple pressure side fitting teeth 77, some of the pressure side fitting teeth 77 overlap with the center side fitting teeth 47 in the radial direction by more than half of the length of the pressure side fitting teeth 77 in the circumferential direction S, and some of the other pressure side fitting teeth 77 do not overlap with the center side fitting teeth 47 in the radial direction by more than half of the length of the pressure side fitting teeth 77 in the circumferential direction S. According to the above aspect, it is possible to achieve a good balance between the retention of clutch oil and its scattering to the outside in the pressure side fitting teeth 77.

[0070] In the clutch device 10 of this embodiment, the clutch center 40 is located radially outside the output shaft holding portion 50, and has a plurality of center-side cam portions 60 having a center-side assist cam surface 60A that generates a force in a direction that moves the pressure plate 70 closer to the clutch center 40 in order to increase the pressing force between the input side rotating plate 20 and the output side rotating plate 22 when the clutch center 40 rotates relative to the pressure plate 70, and a center-side slipper cam surface 60S that moves the pressure plate 70 away from the clutch center 40 in order to reduce the pressing force between the input side rotating plate 20 and the output side rotating plate 22, and an oil discharge hole 49 is formed on each of the sides of the plurality of center-side cam portions 60, and the number of center-side fitting teeth 47 is a multiple of the number of center-side cam portions 60. According to the above aspect, the positional relationship between the center-side cam portions 60 and the oil discharge holes 49 can be made the same. Therefore, the variation in the amount of clutch oil discharged to the outside from each of the oil discharge holes 49 is reduced.

[0071] In the clutch device 10 of this embodiment, the number of center-side cam portions 60 is three, and the number of center-side fitting teeth 47 is a multiple of 3. According to the above aspect, when the clutch center 40 rotates relative to the pressure plate 70, an increase and decrease in the pressing force between the input side rotating plate 20 and the output side rotating plate 22 can be achieved in a well-balanced manner.

[0072] In the clutch device 10 of this embodiment, the spline grooves 48 in which the oil drain holes 49 are formed do not radially overlap at least partially with the pressure-side fitting teeth 77. According to the above aspect, the clutch oil that has flowed out of the clutch center 40 from the oil drain holes 49 can be effectively supplied to the input side rotating plate 20 and the output side rotating plate 22.

[0073] In the clutch device 10 of this embodiment, the spline grooves 48 in which the oil drain holes 49 are formed do not radially overlap with the pressure-side fitting teeth 77. According to the above-described aspect, the clutch oil that has flowed out of the clutch center 40 from the oil drain holes 49 can be more effectively supplied to the input side rotating plate 20 and the output side rotating plate 22.

[0074] In the clutch device 10 of this embodiment, when viewed from the axial direction of the output shaft 15 (i.e., direction D), a straight line passing through the center 15C of the output shaft 15 and an end 77SA on the first circumferential direction S1 side of one pressure-side fitting tooth 77E of the pressure-side fitting teeth 77 adjacent to the center 15C of the output shaft 15 in the circumferential direction S, and an end 77SB on the second circumferential direction S2 side of the other pressure-side fitting tooth 77F of the pressure-side fitting teeth 77 adjacent to the center 15C of the output shaft 15 in the circumferential direction S, are The smallest angle θ5 among the angles formed with a straight line passing through the center 50C of the output shaft holding portion 50 and the end 47SA on the first circumferential direction S1 side of one center-side fitting tooth 47D of the center-side fitting teeth 47 adjacent to each other in the circumferential direction S is smaller than an angle θ6 formed between a straight line passing through the center 50C of the output shaft holding portion 50 and the end 47SB on the second circumferential direction S2 side of the other center-side fitting tooth 47E of the center-side fitting teeth 47 adjacent to each other in the circumferential direction S. According to the above embodiment, it is possible to achieve a good balance between retention of clutch oil and scattering to the outside in the pressure-side fitting tooth 77.

[0075] In the clutch device 10 of this embodiment, the clutch center 40 is provided with an oil drain hole 49 formed in a spline groove 48 penetrating the outer peripheral wall 45 and draining the clutch oil flowing out from the output shaft 15 to the outside of the clutch center 40, the pressure plate 70 is provided with a cylindrical portion 80 that accommodates the tip end 15T of the output shaft 15, and the pressure side fitting teeth 77 are located radially outward of the cylindrical portion 80. According to the above aspect, the clutch oil that flows out from the tip end 15T of the output shaft 15 to the cylindrical portion 80 through the oil drain hole 49 can be efficiently discharged to the outside of the clutch center 40.

[0076] Although the preferred embodiments of the present invention have been described above, the above-described embodiments are merely examples, and the present invention can be embodied in various other forms.

[0077] The overlapping state between the pressure side fitting teeth and the center side fitting teeth as defined in the claims does not matter whether the input side rotating plate and the output side rotating plate are attached to the clutch center and the pressure plate. In other words, if the overlapping state between the pressure side fitting teeth and the center side fitting teeth is as defined in the claims when the input side rotating plate and the output side rotating plate are not attached to the clutch center and the pressure plate, it is included in the scope of the claims. [Explanation of symbols]

[0078] 10 Clutch device 15 Output shaft 20 Input side rotating plate 22 Output side rotating plate 40 Clutch center 45 Outer wall 47 Center side mating teeth 47T End of second direction 48 Spline groove 49 Oil drain hole 50 Output shaft holder 58 Center side fitting part 60 Center side cam part 60A Center side assist cam surface 60S Center side slipper cam surface 70 Pressure Plate 77 Pressure side mating teeth 77T End in the first direction 78 Penetration 80 Cylindrical part 88 Pressure side fitting part 90 Pressure side cam part 90A Pressure side assist cam surface 90S Pressure side slipper cam surface D1 First direction D2 Second 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 which 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 a member that 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 is capable of pressing 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; an outer circumferential wall located radially outward of the output shaft holding portion; a plurality of center side fitting teeth arranged in a circumferential direction, the center side fitting teeth being arranged to hold the output side rotating plate and protruding radially outward from an outer circumferential surface of the outer circumferential wall; a plurality of spline grooves formed between adjacent center side fitting teeth; an oil drain hole formed in the spline groove so as to penetrate the outer peripheral wall and configured to drain clutch oil flowing out from the output shaft to the outside of the clutch center; a center-side cam portion having a center-side assist cam surface that is located radially outside the output shaft holding portion and 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 when the center-side cam portion rotates relative to the pressure plate, and 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, The pressure plate is a plurality of pressure side fitting teeth arranged in a circumferential direction and holding the output side rotating plate; a plurality of pressure-side cam portions each having a pressure-side assist cam surface that generates 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 pressure plate rotates relative to the clutch center, and a pressure-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; a plurality of inter-tooth portions formed between adjacent pressure-side fitting teeth and holding the output-side rotating plate together with the pressure-side fitting teeth; A clutch device in which, between a state in which the center side assist cam surface and the pressure side assist cam surface are in contact with each other and a state in which the center side slipper cam surface and the pressure side slipper cam surface are in contact with each other, when viewed from the radial direction of the output shaft, there exist a state in which a straight line passing through the center of the oil drain hole and parallel to the output shaft passes through the pressure side engaging tooth, and a state in which the straight line passes through the inter-tooth portion.

2. 2. The clutch device according to claim 1, wherein when a direction in which the pressure plate approaches the clutch center is defined as a first direction and a direction in which the pressure plate moves away from the clutch center is defined as a second direction, the clutch center is provided with the oil drain hole located on the first direction side of an edge portion of the pressure side engaging tooth on the first direction side.

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