Clutch device and motorized two-wheeler

Abstract

The present invention relates to a clutch device and a two-wheeled motor vehicle. The clutch device includes: a clutch center portion; and a pressure plate that is arranged so as to be able to approach or separate from the clutch center portion and rotate relative thereto, and is capable of pressing an input-side rotating piece and an output-side rotating piece. The clutch center portion includes: a plurality of center-portion side fitting teeth arranged in the circumferential direction, which hold the input-side rotating piece and the output-side rotating piece and are formed so as to project radially outward from the outer peripheral surface of the outer peripheral wall; and an oil flow path formed at an end portion in a second direction of the center-portion side fitting teeth, and the oil flow path discharges at least the clutch oil flowing on the inner peripheral surface side of the outer peripheral wall to the outside of the clutch center portion.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority based on Japanese Patent Application No. 2022 - 145633 filed on September 13, 2022, and the entire content of the application is incorporated herein by reference into this specification. Technical field

[0003] The present invention relates to a clutch device and a two - wheeled motor vehicle. More specifically, it relates to a clutch device that arbitrarily transmits or cuts off the rotational driving force of an input shaft that is rotationally driven by a prime mover such as an engine, and a two - wheeled motor vehicle equipped with such a clutch device. Background art

[0004] Conventionally, vehicles such as two - wheeled motor vehicles are equipped with a clutch device. The clutch device is disposed between an engine and a drive wheel, and transmits or cuts off the rotational driving force of the engine. The clutch device generally 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 that are connected to an output shaft that transmits the rotational driving force to the drive wheel. The input - side rotating plates and the output - side rotating plates are alternately arranged in the stacking direction, and the transmission or cut - off of the rotational driving force is performed by pressing and separating the input - side rotating plates and the output - side rotating plates.

[0005] For example, Japanese Patent No. 6894972 discloses a clutch device that includes a clutch center portion (clutch member) that holds an output - side rotating plate (passive - 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 portion. The pressure plate is configured to be able to press the input - side rotating plate and the output - side rotating plate. In this way, in the clutch device, the clutch center portion and the pressure plate are assembled and used.

[0006] In addition, in the clutch device of Japanese Patent No. 6894972, as a portion that holds the output - side rotating plate, the clutch center portion has a center - portion side fitting tooth (an outer peripheral wall formed with a spline), and the pressure plate has a pressure - side fitting tooth. In a state where the clutch center portion and the pressure plate are assembled, it is configured such that the center - portion side fitting tooth and the pressure - side fitting tooth overlap in the radial direction.

[0007] Clutch oil flowing out from the output shaft circulates inside the clutch center portion. A part of the clutch oil flows between the clutch center portion and the pressure plate and flows to the outside of the clutch center portion. Here, the input - side rotating plate and the output - side rotating plate held by the center - portion side fitting tooth are disposed outside the clutch center portion. Therefore, it is desired to efficiently flow the clutch oil from the inside of the clutch center portion to supply the clutch oil to the input - side rotating plate and the output - side rotating plate.

[0008] The present invention has been completed in view of the above points, and an object thereof is to provide a clutch device that can efficiently flow clutch oil from the inside to the outside of the clutch center portion to supply the clutch oil to the input-side rotating plate and the output-side rotating plate, and a two-wheeled motor vehicle equipped with the clutch device. Summary of the Invention

[0009] The clutch device according to the present invention transmits or cuts off the rotational driving force of the input shaft to the output shaft, and includes: a clutch center portion that 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, and holds a plurality of output-side rotating plates that are alternately arranged with the input-side rotating plates, and rotates together with the output shaft; and a pressure plate that is provided so as to be able to approach or separate from the clutch center portion and be able to rotate relatively, and can press the input-side rotating plate and the output-side rotating plate. The clutch center portion includes: an output shaft holding portion that is connected to the output shaft; an outer peripheral wall that is located radially outside the output shaft holding portion; a plurality of center portion side fitting teeth arranged in the circumferential direction that hold the output-side rotating plates and are formed so as to project radially outward from the outer peripheral surface of the outer peripheral wall; and an oil flow path that is formed at the end portion in the second direction of the center portion side fitting teeth when the direction in which the pressure plate approaches the clutch center portion is set as the first direction and the direction in which the pressure plate separates from the clutch center portion is set as the second direction. The oil flow path discharges at least the clutch oil flowing on the inner peripheral surface side of the outer peripheral wall to the outside of the clutch center portion.

[0010] According to the clutch device of the present invention, the oil flow path of the clutch center portion is formed at the end portion in the second direction of the center portion side fitting teeth, and discharges at least the clutch oil flowing on the inner peripheral surface side of the outer peripheral wall to the outside of the clutch center portion. Therefore, the clutch oil flowing between the clutch center portion and the pressure plate flows more to the outside of the clutch center portion via the oil flow path. That is, since more clutch oil flows from the inside of the clutch center portion, the clutch oil can be efficiently supplied to the input-side rotating plate and the output-side rotating plate located outside the center portion side fitting teeth.

[0011] In addition, other clutch devices according to the present invention transmit or cut off the rotational driving force of the input shaft to the output shaft, and include: a clutch center portion housed in a clutch housing that holds a plurality of input-side rotating plates rotated by the rotational driving of the input shaft, and holds a plurality of output-side rotating plates alternately arranged with the input-side rotating plates, and rotates together with the output shaft; and a pressure plate provided so as to be able to approach or separate from the clutch center portion and to be able to rotate relatively, and capable of pressing the input-side rotating plates and the output-side rotating plates. The clutch center portion includes: an output shaft holding portion connected to the output shaft; an outer peripheral wall located radially outside the output shaft holding portion; a plurality of center portion side fitting teeth arranged in the circumferential direction, holding the output-side rotating plates, and formed so as to project radially outward from the outer peripheral surface of the outer peripheral wall; and a recess that recesses from the end surface in the second direction of the center portion side fitting teeth toward the first direction when the direction in which the pressure plate approaches the clutch center portion is defined as the first direction and the direction in which the pressure plate separates from the clutch center portion is defined as the second direction, and the recess opens toward the inner peripheral surface side and the outer peripheral side surface of the outer peripheral wall.

[0012] According to other clutch devices according to the present invention, the clutch center portion has a recess that recesses from the end surface in the second direction of the center portion side fitting teeth toward the first direction, and the recess opens toward the inner peripheral surface side and the outer peripheral surface side of the outer peripheral wall. Thus, for example, when the clutch center portion is rotating, the clutch oil flowing on the inner peripheral surface side of the outer peripheral wall can flow to the outer peripheral surface side via the recess, and for example, the clutch oil can be efficiently supplied to the input-side rotating plates and the output-side rotating plates located outside the center portion side fitting teeth.

[0013] According to the present invention, a clutch device can be provided that can efficiently flow clutch oil from the inside to the outside of the clutch center portion and supply the clutch oil to the input-side rotating plates and the output-side rotating plates.

[0014] The above and other elements, features, steps, characteristics, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a cross-sectional view of a clutch device according to an embodiment.

[0016] Figure 2 is a perspective view of a clutch center portion according to an embodiment.

[0017] Figure 3A is a plan view of a clutch center portion according to an embodiment.

[0018] Figure 3Bis a plan view showing an enlarged structure of an oil flow path and its periphery according to an embodiment.

[0019] Figure 3C is a cross-sectional view taken along Figure 3B IIIC-IIIC.

[0020] Figure 4 is a perspective view of a pressure plate according to an embodiment.

[0021] Figure 5 is a plan view of a pressure plate according to an embodiment.

[0022] Figure 6 is a perspective view of a pressure plate according to an embodiment.

[0023] Figure 7 is a plan view of a pressure plate according to an embodiment.

[0024] Figure 8 is a plan view showing a state where the clutch center portion and the pressure plate according to an embodiment are combined.

[0025] Figure 9A is a schematic diagram for explaining the functions of the center-side auxiliary cam surface and the pressure-side auxiliary cam surface.

[0026] Figure 9B is a schematic diagram for explaining the functions of the center-side sliding cam surface and the pressure-side sliding cam surface.

[0027] Figure 10 is a side view of the clutch center portion according to an embodiment. Detailed Embodiment

[0028] Hereinafter, an embodiment of a clutch device according to the present invention will be described with reference to the drawings. It should be noted that the embodiments described herein are not intended to particularly limit the present invention. In addition, components / parts that perform the same functions are denoted by the same reference numerals, and repeated descriptions are appropriately omitted or simplified.

[0029] Figure 1 is a cross-sectional view of a clutch device 10 according to the present embodiment. The clutch device 10 is provided, for example, in a vehicle such as a motorcycle. The clutch device 10 is a device that transmits or cuts off the rotational driving force of an input shaft (crankshaft) of an engine of a motorcycle to an output shaft 15, for example. The clutch device 10 is a device that transmits or cuts off the rotational driving force of the input shaft to a drive wheel (rear wheel) via the output shaft 15. The clutch device 10 is disposed between the engine and the transmission.

[0030] In the following description, the direction in which the pressure plate 70 and the clutch center portion 40 of the clutch device 10 are arranged is defined as direction D, the direction in which the pressure plate 70 approaches the clutch center portion 40 is defined as the first direction D1, and the direction in which the pressure plate 70 separates from the clutch center portion 40 is defined as the second direction D2. Further, the circumferential direction of the clutch center portion 40 and the pressure plate 70 is defined as the circumferential direction S, and with respect to the circumferential direction S, the direction from one pressure-side cam portion 90 to the other pressure-side cam portion 90 is defined as the first circumferential direction S1 (see Figure 5 ), and the direction from the other pressure-side cam portion 90 to the one pressure-side cam portion 90 is defined as the second circumferential direction S2 (see Figure 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 portion 40, and the axial direction of the pressure plate 70 are the same as direction D. Further, the pressure plate 70 and the clutch center portion 40 rotate in the first circumferential direction S1. However, the above directions are merely directions determined for convenience of explanation, and in no way limit the installation manner of the clutch device 10, nor the present invention.

[0031] As shown in Figure 1 , the output shaft 15 is a hollow shaft body. One end of the output shaft 15 rotatably supports the input gear 35 and the clutch housing 30, which will be described later, via a needle bearing 15A. The output shaft 15 fixedly supports the clutch center portion 40 via a nut 15B. That is, the output shaft 15 rotates integrally with the clutch center portion 40. The other end of the output shaft 15 is connected, for example, to a transmission (not shown) of a motorcycle.

[0032] As shown in Figure 1 , the output shaft 15 has a push rod 16A and a pressing member 16B provided adjacent to the push rod 16A in its hollow portion 15H. The hollow portion 15H functions as a flow path for the clutch oil. The clutch oil flows inside the output shaft 15, that is, inside the hollow portion 15H. The push rod 16A and the pressing member 16B are provided so as to be slidable in 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 operating lever (not shown) of a motorcycle, and by operating the clutch operating lever, the push rod 16A slides in the hollow portion 15H and presses the pressing member 16B in the second direction D2. A part of the pressing member 16B protrudes outward (here, in the second direction D2) from the output shaft 15 and is connected to a release bearing 18 provided on the pressure plate 70. The push rod 16A and the pressing member 16B are formed thinner than the inner diameter of the hollow portion 15H, and the fluidity of the clutch oil is ensured in the hollow portion 15H.

[0033] The clutch housing 30 is formed of aluminum alloy. The clutch housing 30 is formed in a bottomed cylindrical shape. AsFigure 1 As shown, the clutch housing 30 has a bottom wall 31 formed in a substantially circular shape and a side wall 33 extending from the edge portion of the bottom wall 31 in the second direction D2. The clutch housing 30 holds a plurality of input-side rotating plates 20.

[0034] As Figure 1 shown, 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 and drives integrally with the clutch housing 30 independently of the output shaft 15.

[0035] The input-side rotating plate 20 is rotationally driven by the rotational drive of the input shaft. As Figure 1 shown, 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 arranged so as to be displaceable along the axial direction of the clutch housing 30. The input-side rotating plate 20 is arranged so as to be able to rotate integrally with the clutch housing 30.

[0036] The input-side rotating plate 20 is a member that abuts against the output-side rotating plate 22. The input-side rotating plate 20 is a flat plate formed in a ring shape. The input-side rotating plate 20 is formed by punching a thin plate made of SPCC (cold-rolled steel sheet) material into a ring shape. Friction members (not shown) composed of a plurality of paper sheets are pasted on the front and back surfaces of the input-side rotating plate 20. Grooves for holding the clutch oil with a depth of several μm to several tens of μm are formed between the friction members.

[0037] As Figure 1 shown, the clutch center portion 40 is housed in the clutch housing 30. The clutch center portion 40 is arranged concentrically with the clutch housing 30. The clutch center portion 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 portion 40 holds a plurality of output-side rotating plates 22 that are alternately arranged with the input-side rotating plates 20 in the direction D. The clutch center portion 40 rotates and drives together with the output shaft 15.

[0038] As Figure 2 shown, the main body 42 includes an annular base wall 43, an outer peripheral wall 45 located radially outside the base wall 43 and extending in the second direction D2, an output shaft holding portion 50 provided at the center of the base wall 43, a plurality of center portion side cam portions 60 connecting the base wall 43 and the outer peripheral wall 45, and a center portion side fitting portion 58.

[0039] 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 so as 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 where the insertion hole 51 is formed. The output shaft 15 is connected to the output shaft holding portion 50.

[0040] As Figure 2 shown, the outer peripheral wall 45 of the clutch center portion 40 is disposed at a radially outer side with respect to the output shaft holding portion 50. A spline fitting portion 46 is provided on the outer peripheral surface 45A of the outer peripheral wall 45. The spline fitting portion 46 has a plurality of center portion side fitting teeth 47 that extend in the axial direction of the clutch center portion 40 along the outer peripheral surface 45A of the outer peripheral wall 45, a plurality of spline grooves 48 that are formed between adjacent center portion side fitting teeth 47 and extend in the axial direction of the clutch center portion 40, and an oil discharge hole 49. The center portion side fitting teeth 47 hold the output side rotating piece 22. The plurality of center portion side fitting teeth 47 are arranged in the circumferential direction S. The plurality of center portion side fitting teeth 47 are formed at equal intervals in the circumferential direction S. The plurality of center portion side fitting teeth 47 are formed in the same shape. The center portion side fitting teeth 47 project radially outward from the outer peripheral surface 45A of the outer peripheral wall 45. The number of the center portion side fitting teeth 47 is preferably a multiple of the number of the center portion side cam portions 60. In the present embodiment, as will be described later, the number of the center portion side cam portions 60 is 3, and the number of the center portion side fitting teeth 47 is 30. It should be noted that the number of the center portion side fitting teeth 47 may not be a multiple of the number of the center portion side cam portions 60. The oil discharge hole 49 is formed so as to penetrate the outer peripheral wall 45 in the radial direction. The oil discharge hole 49 is formed between adjacent center portion 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 portion side cam portion 60. The oil discharge hole 49 is formed on the side of the center portion side sliding cam surface 60S of the center portion side cam portion 60. The oil discharge hole 49 is formed at a position closer to the first circumferential direction S1 side than the center portion side sliding cam surface 60S. The oil discharge hole 49 is formed at a position closer to the second circumferential direction S2 side than a protruding portion 54 described later. In the present embodiment, three oil discharge holes 49 are formed at each of three positions in the circumferential direction S of the outer peripheral wall 45. The oil discharge holes 49 are arranged at equal intervals in the circumferential direction S. The oil discharge hole 49 communicates the inside and the outside of the clutch center portion 40. The oil discharge hole 49 is a hole for discharging the clutch oil that flows out from the output shaft 15 into the clutch center portion 40 to the outside of the clutch center portion 40. Here, the oil discharge hole 49 discharges the clutch oil flowing on the inner peripheral surface 45B side of the outer peripheral wall 45 to the outside of the clutch center portion 40. At least a part of the oil discharge hole 49 is provided at a position facing a pressure side fitting portion 88 described later.

[0041] As Figure 2As shown, the clutch center portion 40 is provided with a plurality of oil flow paths 41 formed in the center portion side engaging teeth 47. As Figure 10 shown, the oil flow path 41 is formed at the end 47E in the second direction D2 of the center portion side engaging teeth 47. The oil flow path 41 opens toward the outer peripheral surface 45A side and the inner peripheral surface 45B side of the outer peripheral wall 45. The oil flow path 41 is a flow path that connects the outer peripheral surface 45A and the inner peripheral surface 45B of the outer peripheral wall 45. The oil flow path 41 is a flow path that discharges at least the clutch oil flowing on the inner peripheral surface 45B side of the outer peripheral wall 45 to the outside of the clutch center portion 40. In the present embodiment, the oil flow path 41 is a groove that is recessed from the end surface 47T in the second direction D2 of the center portion side engaging teeth 47 (also refer to Figure 3C ). The oil flow path 41 is an example of a recess. As Figure 3A shown, the oil flow path 41 is formed in a substantially circular shape (also refer to Figure 3B ). It should be noted that the shape of the oil flow path 41 is not particularly limited. A part of the plurality of oil flow paths 41 is disposed radially outside the center portion side cam portion 60 described later. A part of the plurality of oil flow paths 41 is disposed radially outside the center portion side cam hole 43H described later. A part of the plurality of oil flow paths 41 is disposed radially outside the through hole 43P described later. The oil flow path 41 is provided at a position facing the pressure side engaging portion 88 (refer to Figure 4 ) of the pressure plate 70 described later. As Figure 2As shown, a center-side engaging tooth 47C without an oil flow path 41 is disposed between a center-side engaging tooth 47A formed on one center side of the oil flow path 41 and another center-side engaging tooth 47B formed on one center side of the oil flow path 41. In the present embodiment, among the plurality of center-side engaging teeth 47 arranged in the circumferential direction S, the oil flow path 41 is formed every other one, but the oil flow path 41 may be formed every two, or may be formed every three or more. It should be noted that the oil flow path 41 may be formed in adjacent center-side engaging teeth 47 respectively. The oil flow path 41 is formed, for example, by abutting a die pin against an end face 47T in the second direction D2 of the center-side engaging tooth 47 when the pressure plate 70 formed using a mold is removed from the mold, or by machining. It should be noted that the oil flow path 41 is also a flow path for guiding clutch oil (for example, clutch oil adhering to the surface 47S of the center-side engaging tooth 47) flowing on the outer peripheral surface 45A side of the outer peripheral wall 45 to the inside of the clutch center 40. For example, when the rotation of the clutch center 40 stops (for example, when the engine stops), in the oil flow path 41 located above the clutch center 40, the clutch oil adhering to the surface 47S of the center-side engaging tooth 47 flows to the inner peripheral surface 45B of the clutch center 40 via the oil flow path 41 by gravity. In addition, when the rotation of the clutch center 40 stops, in the oil flow path 41 located below the clutch center 40, the clutch oil adhering to the inner peripheral surface 45B of the outer peripheral wall 45 of the center-side engaging tooth 47 flows to the surface 47S of the center-side engaging tooth 47 via the oil flow path 41 by gravity. That is, when the clutch center 40 is not rotating, the clutch oil flows from the inside of the clutch center 40 to the outside via the oil flow path 41, and sometimes flows from the outside to the inside simultaneously.

[0042] The output-side rotating piece 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 piece 22 is held by the center-side engaging tooth 47 and the spline groove 48 of the clutch center 40 by spline fitting. Another part of the output-side rotating piece 22 is held by a pressure-side engaging tooth 77 (refer to Figure 4 ) of the pressure plate 70 to be described later. The output-side rotating piece 22 is arranged so as to be displaceable along the axial direction of the clutch center 40. The output-side rotating piece 22 is arranged so as to be rotatable integrally with the clutch center 40.

[0043] The output-side rotating plate 22 is a member that abuts against the input-side rotating plate 20. The output-side rotating plate 22 is formed as an annular flat plate. The output-side rotating plate 22 is formed by punching a thin plate made of SPCC material into an annular shape. Grooves for holding the clutch oil with 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. Surface hardening treatments are respectively performed on the front and back surfaces of the output-side rotating plate 22 to improve wear resistance. It should be noted that the friction members 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 respectively provided on the input-side rotating plate 20 and the output-side rotating plate 22.

[0044] The central portion side cam portion 60 is formed in a table shape having a cam surface, and this cam surface is constituted by an inclined surface of an assist & slip (registered trademark) mechanism that generates an assist torque, which is a force that increases the pressing force (contact force) between the input-side rotating plate 20 and the output-side rotating plate 22, or a slip torque, which is a force that causes the input-side rotating plate 20 and the output-side rotating plate 22 to separate in advance and transition to a semi-clutch state. The central portion side cam portion 60 is formed so as to protrude from the base wall 43 in the second direction D2. As Figure 3A shown, the central portion side cam portions 60 are arranged at equal intervals in the circumferential direction S of the clutch central portion 40. In the present embodiment, the clutch central portion 40 has three central portion side cam portions 60, but the number of the central portion side cam portions 60 is not limited to three.

[0045] As Figure 3A shown, the central portion side cam portion 60 is located radially outside the output shaft holding portion 50. The central portion side cam portion 60 has a central portion side assist cam surface 60A and a central portion side slip cam surface 60S. The central portion side assist cam surface 60A is configured to generate a force in the direction that causes the pressure plate 70 to approach the clutch central portion 40 in order to increase the pressing force (contact force) between the input-side rotating plate 20 and the output-side rotating plate 22 when relatively rotating with respect 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 central portion 40 does not change, and the pressure plate 70 does not need to physically approach the clutch central portion 40. It should be noted that the pressure plate 70 may also be physically displaced with respect to the clutch central portion 40. The central portion side slip cam surface 60S is configured to separate the pressure plate 70 from the clutch central portion 40 in order to reduce the pressing force (contact force) between the input-side rotating plate 20 and the output-side rotating plate 22 when relatively rotating with respect to the pressure plate 70. Among the central portion side cam portions 60 adjacent in the circumferential direction S, the central portion side assist cam surface 60A of one central portion side cam portion 60L and the central portion side slip cam surface 60S of the other central portion side cam portion 60M are arranged to face each other in the circumferential direction S.

[0046] AsFigure 2 As shown, the clutch center portion 40 has a plurality of (three in this embodiment) protruding portions 54. The protruding portions 54 are members that support the pressure plate 70. The plurality of protruding portions 54 are arranged at equal intervals in the circumferential direction S. The protruding portions 54 are formed in a cylindrical shape. The protruding portions 54 are located radially outside the output shaft holding portion 50. The protruding portions 54 extend toward the pressure plate 70 (i.e., toward the second direction D2). The protruding portions 54 are provided on the base wall 43. A threaded hole 54H into which a bolt 28 (refer to Figure 1 ) is inserted is formed in the protruding portion 54. The threaded hole 54H extends in the axial direction of the clutch center portion 40.

[0047] As Figure 2 and Figure 3A shown, the clutch center portion 40 has a center portion side cam hole 43H that penetrates a part of the base wall 43. The center portion side cam hole 43H penetrates the base wall 43 in the direction D. The center portion side cam hole 43H extends from the side of the output shaft holding portion 50 to the outer peripheral wall 45. The center portion side cam hole 43H is formed between the center portion side auxiliary cam surface 60A of the center portion side cam portion 60 and the protruding portion 54. When viewed from the axial direction of the clutch center portion 40, a part of the center portion side auxiliary cam surface 60A and the center portion side cam hole 43H overlap.

[0048] As Figure 2 and Figure 3A shown, the clutch center portion 40 has a through hole 43P that penetrates a part of the base wall 43. The through hole 43P penetrates the base wall 43 in the direction D. The through hole 43P is formed between the center portion side sliding cam surface 60S of the center portion side cam portion 60 and the center portion side cam hole 43H. It is formed between the center portion side sliding cam surface 60S of the center portion side cam portion 60 and the protruding portion 54. The through hole 43P is located on the first circumferential direction S1 side with respect to the center portion side sliding cam surface 60S. The through hole 43P is located on the second circumferential direction S2 side with respect to the protruding portion 54. An oil discharge hole 49 is formed on the radial outer side of the through hole 43P. The through hole 43P is smaller than the center portion side cam hole 43H. The through hole 43P connects the inside and outside of the clutch center portion 40. The through hole 43P is configured to guide the clutch oil flowing outside the clutch center portion 40 into the clutch center portion 40. More specifically, as Figure 1 shown by the arrow FS, the clutch oil that flows out from the output shaft 15 toward the clutch center portion 40 flows into the clutch center portion 40 via the through hole 43P.

[0049] As Figure 2As shown, the central side fitting portion 58 is located radially outside the output shaft holding portion 50. The central side fitting portion 58 is located radially outside the central side cam portion 60. The central side fitting portion 58 is located on the second direction D2 side with respect to the central side cam portion 60. The central side fitting portion 58 is formed on the inner peripheral surface 45B of the outer peripheral wall 45. The central side fitting portion 58 is configured to externally fit the pressure side fitting portion 88 (refer to Figure 4 ) in a slidable manner. The inner diameter of the central side fitting portion 58 is formed with a fit tolerance that allows the flow of the clutch oil flowing out from the tip portion 15T of the output shaft 15 (refer to Figure 1 ) with respect to the pressure side fitting portion 88. That is, a gap is formed between the central side fitting portion 58 and the pressure side fitting portion 88 described later. In the present embodiment, for example, the central 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 central 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 flowed, but is, for example, 0.1 mm or more and 0.5 mm or less.

[0050] As Figure 1 shown, the pressure plate 70 is provided so as to be able to approach or separate from the clutch center portion 40 and to be able to rotate relatively. The pressure plate 70 is configured to be able to press the input side rotating piece 20 and the output side rotating piece 22. The pressure plate 70 is arranged concentrically with the clutch center portion 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 on the second direction D2 side of the main body 72 and extends radially outward. The main body 72 protrudes in the first direction D1 more than the flange 98. The pressure plate 70 holds a plurality of output side rotating pieces 22 that are alternately arranged with the input side rotating piece 20. The output side rotating piece 22 is provided so as to be able to displace in the axial direction of the pressure plate 70. The output side rotating piece 22 is provided so as to be able to rotate integrally with the pressure plate 70.

[0051] As Figure 4 shown, the main body 72 includes a cylindrical portion 80, a plurality of pressure side cam portions 90, a pressure side fitting portion 88, and a spring housing portion 84 (also refer to Figure 6 ).

[0052] The cylindrical portion 80 is formed in a cylindrical shape. The cylindrical portion 80 is integrally formed with the pressure side cam portion 90. The cylindrical portion 80 houses the tip portion 15T of the output shaft 15 (refer to Figure 1 ). The cylindrical portion 80 houses the release bearing 18 (refer to Figure 1 ). The cylindrical portion 80 is a portion that receives the pressing force from the pressing member 16B. The cylindrical portion 80 is a portion that receives the clutch oil that has flowed out from the tip portion 15T of the output shaft 15.

[0053] The pressure-side cam portion 90 is formed in a table shape having a cam surface, and the cam surface is constituted by an inclined surface of an assist & slip (registered trademark) mechanism that slides relative to the center-side cam portion 60 to generate an assist torque or a slip torque. The pressure-side cam portion 90 is formed so as to protrude in the first direction D1 more than the flange 98. As Figure 5 shown, the pressure-side cam portions 90 are arranged at equal intervals in the circumferential 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 the pressure-side cam portions 90 is not limited to three.

[0054] As Figure 5 shown, 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 (also refer to Figure 7 ) and a pressure-side slip cam surface 90S. The pressure-side assist cam surface 90A is configured to be able to contact the center-side assist cam surface 60A. The pressure-side assist cam surface 90A is configured to generate a force in the direction of approaching the clutch center portion 40 of the pressure plate 70 in order to increase the pressing force (contact force) between the input-side rotating piece 20 and the output-side rotating piece 22 when relatively rotating with respect to the clutch center portion 40. The pressure-side slip cam surface 90S is configured to be able to contact the center-side slip cam surface 60S. The pressure-side slip cam surface 90S is configured to separate the pressure plate 70 from the clutch center portion 40 in order to reduce the pressing force (contact force) between the input-side rotating piece 20 and the output-side rotating piece 22 when relatively rotating with respect to the clutch center portion 40. Among the pressure-side cam portions 90 adjacent in the circumferential direction S, the pressure-side assist cam surface 90A of one pressure-side cam portion 90L and the pressure-side slip cam surface 90S of the other pressure-side cam portion 90M are arranged to face each other in the circumferential direction S.

[0055] Here, the functions 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 portion 40, as Figure 9A shown, a rotational force in the first circumferential direction S1 is applied to the pressure plate 70. Therefore, due to the action of the center-side assist cam surface 60A and the pressure-side assist cam surface 90A, a force in the first direction D1 is generated in the pressure plate 70. Thereby, the contact force between the input-side rotating piece 20 and the output-side rotating piece 22 is increased.

[0056] 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 reverse torque is generated, as Figure 9BAs shown, a rotational force in the first circumferential direction S1 is applied to the center portion 40 of the clutch. Thus, due to the action of the center portion side sliding cam surface 60S and the pressure side sliding cam surface 90S, the pressure plate 70 moves in the second direction D2, releasing the pressing force between the input side rotating piece 20 and the output side rotating piece 22. Thereby, it is possible to avoid adverse conditions for the engine and transmission caused by reverse torque.

[0057] As Figure 4 and Figure 5 shown, the pressure plate 70 has a pressure side cam hole 73H that penetrates a part of the main body 72 and the flange 98. 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 a position radially outside the pressure side fitting portion 88. The pressure side cam hole 73H is formed to penetrate between adjacent pressure side cam portions 90. The pressure side cam hole 73H is formed to penetrate between the pressure side auxiliary cam surface 90A and the pressure side sliding cam surface 90S of adjacent pressure side cam portions 90. As Figure 5 and Figure 7 shown, when viewed in the axial direction of the pressure plate 70, a part of the pressure side auxiliary cam surface 90A and the pressure side cam hole 73H overlap.

[0058] As Figure 6 and Figure 7 shown, a 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. The spring housing portion 84 houses the pressure spring 25 (refer to Figure 1 ). An insertion hole 84H for inserting the projection portion 54 (refer to Figure 2 ) is formed to penetrate the spring housing portion 84. That is, the insertion hole 84H is formed to penetrate the pressure side cam portion 90. The insertion hole 84H is formed in an elliptical shape.

[0059] As Figure 1 shown, the pressure spring 25 is housed in the spring housing portion 84. The pressure spring 25 is held by the projection portion 54 inserted into the insertion hole 84H of the spring housing portion 84. The pressure spring 25 applies a force to the pressure plate 70 toward the clutch center portion 40 (i.e., toward the first direction D1). The pressure spring 25 is, for example, a helical spring obtained by coiling spring steel into a spiral shape.

[0060] As Figure 4 shown, the pressure side fitting portion 88 is provided on the main body 72. The pressure side fitting portion 88 is located radially outside the pressure side cam portion 90. The pressure side fitting portion 88 is located on the second direction D2 side of the pressure side cam portion 90. The pressure side fitting portion 88 is configured to be slidably inserted into the center portion side fitting portion 58 (refer to Figure 2 ).

[0061] like Figure 4 As shown, the pressure plate 70 includes a plurality of pressure side interlocking teeth 77 formed on the flange 98. The pressure side interlocking teeth 77 hold the output side rotating piece 22. The pressure side interlocking teeth 77 are located radially outward from the cylindrical portion 80. The pressure side interlocking teeth 77 are located radially outward from the pressure side cam portion 90. The pressure side interlocking teeth 77 are located radially outward from the pressure side interlocking portion 88. The pressure side interlocking teeth 77 are formed on the interlocking tooth forming surface 98B of the flange 98. The pressure side interlocking teeth 77 protrude from the interlocking tooth forming surface 98B toward the first direction D1. The plurality of pressure side interlocking teeth 77 are arranged in the circumferential direction S. The plurality of pressure side interlocking teeth 77 are arranged at equal intervals in the circumferential direction S. It should be noted that, in the present embodiment, a portion of the pressure side interlocking teeth 77 is removed, so the interval of the portion is expanded, but the other adjacent pressure side interlocking teeth 77 are arranged at equal intervals.

[0062] Figure 8 4 is a plan view showing a state where the clutch center 40 and the pressure plate 70 are assembled. Figure 8 In the state shown, the pressure side auxiliary cam surface 90A and the center side auxiliary cam surface 60A are not in contact, and the pressure side sliding cam surface 90S and the center side sliding cam surface 60S are not in contact. At this time, the pressure plate 70 is closest to the clutch center 40. Figure 8 In the state shown (the state when assembled), the circumferential distance L1 between the protrusion 54 and the end 84HA on the pressure side auxiliary cam surface 90A side (i.e., the first circumferential direction S1 side) of the insertion hole 84H is shorter than the circumferential distance L2 between the protrusion 54 and the end 84HB on the pressure side sliding cam surface 90S side (i.e., the second circumferential direction S2 side) of the insertion hole 84H in the normal state.

[0063] like Figure 1 As shown in FIG. 1 , the stopper plate 100 is provided in a manner capable of contacting the pressure plate 70. The stopper plate 100 is a member for preventing the pressure plate 70 from being separated from the clutch center 40 in the second direction D2 by a predetermined distance or more. The stopper plate 100 is fixed to the boss 54 of the clutch center 40 by the bolt 28. The pressure plate 70 is fixed by tightening the bolt 28 to the boss 54 via the stopper plate 100 in a state where the boss 54 of the clutch center 40 and the pressure spring 25 are arranged in the spring receiving portion 84. The stopper plate 100 is formed in a substantially triangular shape in a plan view.

[0064] Here, when the pressure plate 70 contacts the stopper plate 100, the pressure-side sliding cam surface 90S and the center-side sliding cam surface 60S contact each other with 50% or more and 90% or less of the area of the pressure-side sliding cam surface 90S and 50% or more and 90% or less of the area of the center-side sliding cam surface 60S, respectively. Further, when the pressure plate 70 contacts the stopper plate 100, the pressure spring 25 separates from the side wall of the spring housing portion 84. That is, the pressure spring 25 is not clamped between the protrusion portion 54 and the spring housing portion 84, suppressing excessive stress from being applied to the protrusion portion 54.

[0065] A predetermined amount of clutch oil is filled in the clutch device 10. The clutch oil flows into the clutch center portion 40 and the pressure plate 70 through the hollow portion 15H of the output shaft 15, and then is 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. Moreover, the clutch oil flowing on the inner peripheral surface 45B side of the outer peripheral wall 45 of the clutch center portion 40 is discharged to the outside of the clutch center portion 40 through the oil flow path 41 as shown by the arrow FM in Figure 3A FIG. In addition, the clutch oil flows from the outside of the clutch center portion 40 into the inside of the clutch center portion 40 through the center-side cam hole 43H and the through hole 43P through the hollow portion 15H of the output shaft 15. The clutch oil suppresses heat absorption and wear of friction members. The clutch device 10 of the present embodiment is a so-called wet multi-plate friction clutch device.

[0066] 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 transmits and cuts off the rotational driving force of the engine by the driver operating the clutch operating lever.

[0067] In the clutch device 10, when the driver of the motorcycle does not operate the clutch operating lever, the clutch release mechanism (not shown) does not press the push rod 16A, so the pressure plate 70 presses the input-side rotating plate 20 by the acting force (elastic force) of the pressure spring 25. As a result, the clutch center portion 40 is in a clutch-on state in which the input-side rotating plate 20 and the output-side rotating plate 22 abut against each other and are frictionally connected, and rotates and drives. That is, the rotational driving force of the engine is transmitted to the clutch center portion 40 and the output shaft 15 rotates and drives.

[0068] In the clutch-on state, the clutch oil flowing in the hollow portion 15H of the output shaft 15 and flowing out from the tip portion 15T of the output shaft 15 falls or flies into the cylindrical portion 80 and adheres (refer to Figure 1The arrow F). The clutch oil attached inside the cylindrical portion 80 is guided into the clutch central portion 40. As a result, the clutch oil flows out to the outside of the clutch central portion 40 through the oil discharge hole 49. In addition, the clutch oil flows out to the outside of the clutch central portion 40 through the oil flow path 41 and the gap between the central portion side fitting portion 58 and the pressure side fitting portion 88. And, the clutch oil that has flowed out to the outside of the clutch central portion 40 is supplied to the input side rotating piece 20 and the output side rotating piece 22.

[0069] On the other hand, in the clutch device 10, when the driver of the motorcycle operates the clutch operating lever in the clutch open state, the clutch release mechanism (not shown) presses the push rod 16A, so the pressure plate 70 displaces in the direction (second direction D2) of separating from the clutch central portion 40 against the acting force of the pressure spring 25. As a result, the clutch central portion 40 becomes a clutch closed state in which the frictional connection between the input side rotating piece 20 and the output side rotating piece 22 is eliminated, so it becomes a state where the rotational drive weakens or the rotational drive stops. That is, the rotational driving force of the engine is cut off with respect to the clutch central portion 40.

[0070] In the clutch closed state, the clutch oil that flows in the hollow portion 15H of the output shaft 15 and flows out from the tip portion 15T of the output shaft 15 is guided into the clutch central portion 40 in the same manner as in the clutch open state. At this time, since the pressure plate 70 is separated from the clutch central portion 40, the amount of engagement between the central portion 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 to the outside of the clutch central portion 40 more actively and flows to various parts inside the clutch device 10. In particular, the clutch oil can be actively guided between the input side rotating piece 20 and the output side rotating piece 22 that are separated from each other.

[0071] And, when the driver releases the clutch operating lever in the clutch closed state, the pressing of the pressure plate 70 by the clutch release mechanism (not shown) via the pressing member 16B is released, so the pressure plate 70 displaces in the direction (first direction D1) of approaching the clutch central portion 40 by the acting force of the pressure spring 25.

[0072] As described above, in the clutch device 10 according to the present embodiment, the oil flow path 41 in the clutch center portion 40 is formed at the end portion 47E in the second direction D2 of the center portion side engaging teeth 47, and at least discharges the clutch oil flowing on the inner peripheral surface 45B side of the outer peripheral wall 45 to the outside of the clutch center portion 40. Therefore, the clutch oil flowing between the clutch center portion 40 and the pressure plate 70 flows more to the outside of the clutch center portion 40 via the oil flow path 41. That is, since more clutch oil flows from the inside of the clutch center portion 40, the clutch oil can be efficiently supplied to the input side rotating piece 20 and the output side rotating piece 22 located outside the center portion side engaging teeth 47.

[0073] In the clutch device 10 of the present embodiment, the oil flow path 41 is a groove recessed from the end surface 47T in the second direction D2 of the center portion side engaging teeth 47 toward the first direction D1. According to the above solution, the clutch oil inside the clutch center portion 40 can flow more to the outside with a relatively simple structure.

[0074] In the clutch device 10 of the present embodiment, the clutch center portion 40 has a plurality of center portion side cam portions 60, which are located radially outside the output shaft holding portion 50, and have at least one of a center portion side auxiliary cam surface 60A that generates a force in a direction to bring the pressure plate 70 closer to the clutch center portion 40 to increase the pressing force between the input side rotating piece 20 and the output side rotating piece 22 and a center portion side sliding cam surface 60S that separates the pressure plate 70 from the clutch center portion 40 to decrease the pressing force between the input side rotating piece 20 and the output side rotating piece 22 when relatively rotating with respect to the pressure plate 70. The oil flow path 41 is arranged radially outside the center portion side cam portion 60. When the clutch center portion 40 rotates, the clutch oil is likely to accumulate around the center portion side cam portion 60. Therefore, by arranging the oil flow path 41 radially outside the center portion side cam portion 60, the accumulated clutch oil can flow effectively from the oil flow path 41 to the outside. Thereby, more clutch oil can flow to the outside of the clutch center portion 40.

[0075] In the clutch device 10 of the present embodiment, the oil flow path 41 is arranged radially outside the through hole 43P. Since the clutch oil flows into the through hole 43P from the outside of the clutch center portion 40, by arranging the oil flow path 41 radially outside the through hole 43P, the clutch oil can flow effectively from the oil flow path 41 to the outside (i.e., toward the input side rotating piece 20 and the output side rotating piece 22). Thereby, more clutch oil can flow to the input side rotating piece 20 and the output side rotating piece 22.

[0076] In the clutch device 10 of the present embodiment, the clutch center portion 40 includes a center portion side fitting portion 58 formed on the inner peripheral surface 45B of the outer peripheral wall 45, the pressure plate 70 includes a pressure side fitting portion 88 that is slidably fitted into the center portion side fitting portion 58, and an oil flow path 41 is provided at a position facing the pressure side fitting portion 88. According to the above solution, the clutch oil inside the clutch center portion 40 can flow more between the center portion side fitting portion 58 and the pressure side fitting portion 88 via the oil flow path 41. Thus, while reducing the sliding resistance between the center portion side fitting portion 58 and the pressure side fitting portion 88, more clutch oil can flow to the outside of the clutch center portion 40.

[0077] In the clutch device 10 of the present embodiment, a center portion side engaging tooth 47C without the oil flow path 41 is disposed between one center portion side engaging tooth 47A having the oil flow path 41 and another center portion side engaging tooth 47B having the oil flow path 41. According to the above solution, the clutch oil can flow to the outside of the clutch center portion 40 in a balanced manner.

[0078] The preferred embodiments of the present invention have been described above. However, the above embodiments are merely illustrative, and the present invention can be implemented in various other ways.

[0079] In the above embodiment, the center portion side cam portion 60 has a center portion side auxiliary cam surface 60A and a center portion side sliding cam surface 60S, but having at least either one is sufficient.

[0080] In the above embodiment, the pressure side cam portion 90 has a pressure side auxiliary cam surface 90A and a pressure side sliding cam surface 90S, but having at least either one is sufficient.

[0081] Although the preferred embodiments of the present invention have been described above, it should be understood that changes and modifications within the scope and spirit of the present invention are obvious to those skilled in the art. Therefore, the scope of the present invention is determined only by the appended claims.

Claims

1. A clutch device that transmits or cuts off the rotational driving force of an input shaft to an output shaft, wherein, Comprising: A clutch center portion, which is housed in a clutch housing that holds a plurality of input-side rotating plates rotated by the rotational drive of the input shaft, holds a plurality of output-side rotating plates arranged alternately with the input-side rotating plates, and rotates together with the output shaft; And A pressure plate, which is provided so as to be able to approach or separate from the clutch center portion and be relatively rotatable, and can press the input-side rotating plates and the output-side rotating plates, The clutch center portion comprises: An output shaft holding portion, which is connected to the output shaft; An outer peripheral wall, which is located radially outside the output shaft holding portion and is formed with an oil discharge hole that penetrates the outer peripheral wall in the radial direction; A plurality of center portion side engaging teeth arranged in the circumferential direction, which hold the output-side rotating plates and are formed to protrude radially outward from the outer peripheral surface of the outer peripheral wall; and An oil flow path, which is formed at the end portion in the second direction of the center portion side engaging teeth when the direction in which the pressure plate approaches the clutch center portion is set as the first direction and the direction in which the pressure plate separates from the clutch center portion is set as the second direction, The oil flow path discharges at least the clutch oil flowing on the inner peripheral surface side of the outer peripheral wall to the outside of the clutch center portion.

2. The clutch device according to claim 1, The oil flow path is a groove that is recessed from the end portion in the second direction of the center portion side engaging teeth toward the first direction.

3. The clutch device according to claim 1 or 2, The clutch center portion has a plurality of center portion side cam portions, which are located radially outside the output shaft holding portion and have at least one of a center portion side auxiliary cam surface that generates a force in the direction in which the pressure plate approaches the clutch center portion to increase the pressing force between the input-side rotating plates and the output-side rotating plates and a center portion side sliding cam surface that separates the pressure plate from the clutch center portion to reduce the pressing force between the input-side rotating plates and the output-side rotating plates when relatively rotated with respect to the pressure plate, The oil flow path is arranged radially outside the center portion side cam portion.

4. The clutch device according to claim 1 or 2, The clutch center portion has: A plurality of center portion side cam portions, which are located radially outside the output shaft holding portion and have at least one of a center portion side auxiliary cam surface that generates a force in the direction in which the pressure plate approaches the clutch center portion to increase the pressing force between the input-side rotating plates and the output-side rotating plates and a center portion side sliding cam surface that separates the pressure plate from the clutch center portion to reduce the pressing force between the input-side rotating plates and the output-side rotating plates when relatively rotated with respect to the pressure plate; and A through hole, which is formed between adjacent center portion side cam portions, The oil flow path is arranged radially outside the through hole.

5. The clutch device according to claim 1 or 2, The clutch center portion comprises a center portion side engaging portion formed on the inner peripheral surface of the outer peripheral wall, The pressure plate includes a pressure-side fitting portion that is slidably fitted into the fitting portion on the center portion side. The oil flow path is provided at a position facing the pressure-side fitting portion.

6. The clutch device according to claim 1 or 2, A center portion side fitting tooth without the oil flow path is disposed between one center portion side fitting tooth having the oil flow path and another center portion side fitting tooth having the oil flow path.

7. A two-wheeled motor vehicle including the clutch device according to claim 1 or 2.

8. A clutch device that transmits or cuts off the rotational driving force of an input shaft to an output shaft, wherein, Comprising: A clutch center portion that is housed in a clutch housing that holds a plurality of input-side rotating pieces that are rotationally driven by the rotational drive of the input shaft, holds a plurality of output-side rotating pieces that are alternately arranged with the input-side rotating pieces, and is rotationally driven together with the output shaft; And A pressure plate that is provided so as to be able to approach or separate from and relatively rotate with respect to the clutch center portion, and can press the input-side rotating piece and the output-side rotating piece. The clutch center portion includes: An output shaft holding portion that is connected to the output shaft; An outer peripheral wall that is located radially outside the output shaft holding portion and is formed with an oil discharge hole that penetrates the outer peripheral wall in the radial direction; A plurality of center portion side fitting teeth arranged in the circumferential direction that hold the output-side rotating pieces and are formed so as to project radially outward from the outer peripheral surface of the outer peripheral wall; and A recess that depresses from the end surface in the second direction of the center portion side fitting tooth toward the first direction when the direction in which the pressure plate approaches the clutch center portion is the first direction and the direction in which the pressure plate separates from the clutch center portion is the second direction. The recess opens toward the inner peripheral surface side and the outer peripheral side surface of the outer peripheral wall to discharge the clutch oil flowing on the inner peripheral surface side of the outer peripheral wall to the outside of the clutch center portion.

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