Clutch device

Abstract

A centrifugal clutch mechanism 120 of a clutch device 10 includes: a plurality of weight members 130 configured to be movable from an inside position in a radial direction M to an outside position by centrifugal force accompanying rotation of a clutch housing 30; a holding member 140 for holding the weight member 130 movably between the inside position in the radial direction M and the outside position in the radial direction; and a rotation suppression mechanism 190 for applying force in a second direction H2, which is a direction opposite to a first direction H1, to the weight member 130 when such force that the weight member 130 rotates in the first direction H1 around a center line 130CL of the weight member 130 and extending in an axial direction of an output shaft 15.

Description

Clutch device

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

[0002] Straddle-type vehicles such as motorcycles are equipped with a clutch device that can transmit and interrupt the rotational driving force of a power source such as an engine to a driving wheel. For example, Patent Document 1 discloses a clutch device that has an input member (hereinafter referred to as an input shaft) connected to the engine, an output member (hereinafter referred to as an output shaft) connected to the driving wheel, a clutch member (hereinafter referred to as a clutch center) connected to the output shaft, and a pressure member that can move toward or away from the clutch center.

[0003] The clutch device in Patent Document 1 also includes a centrifugal clutch mechanism that includes a weight member that moves radially and a holding member that holds the weight member. The weight member moves from a radially inner position to a radially outer position due to centrifugal force generated by rotation of the clutch housing, and transmits the driving force of the engine to the wheels by pressing a driving clutch plate (hereinafter referred to as an input side rotating plate) and a driven clutch plate (hereinafter referred to as an output side rotating plate) together.

[0004] JP 2022-30211 A

[0005] In the centrifugal clutch mechanism described in Patent Document 1, when the weight member held by the holding member moves in the radial direction, there is a risk that a force that rotates the weight member in the circumferential direction may be generated due to engine vibration, etc. If such a force is generated, there is a risk that the weight member may vibrate, generating abnormal noise, or that the weight member may not be able to move smoothly in the radial direction.

[0006] The present invention has been made in view of the above points, and an object of the present invention is to provide a clutch device that suppresses vibration of a weight member and allows the weight member to move smoothly in the radial direction.

[0007] The clutch device according to the present invention is a clutch device that transmits or cuts off the rotational driving force of an input shaft to an output shaft, and includes: a clutch center that is accommodated in a clutch housing that holds a plurality of input side rotating plates that are rotationally driven by the rotational drive of the input shaft and that rotates together with the output shaft; a pressure member that is provided so as to be able to approach or move away from the clutch center and to be rotatable relative to the clutch center, that holds at least some of the plurality of output side rotating plates that are arranged alternately with the input side rotating plates, and that can press the input side rotating plates and the output side rotating plates; and a plurality of weight members that are configured to be movable from a radially inner position to an outer position by centrifugal force that accompanies the rotation of the clutch housing, and that when the weight members are at the radially outer position, press the input side rotating plates and the and a centrifugal clutch mechanism that presses the input side rotating plate against the output side rotating plate to enable transmission of the rotational driving force of the input shaft to the output shaft, and that, when the weight member is in the radially inner position, releases the pressing force between the input side rotating plate and the output side rotating plate to block transmission of the rotational driving force of the input shaft to the output shaft, wherein the centrifugal clutch mechanism comprises: a holding member that holds the weight member movably between the radially inner position and the radially outer position; and a rotation suppressing mechanism that, when a force is applied to the weight member such that the weight member rotates in a first direction about a center line of the weight member that is extending in the axial direction of the output shaft, applies a force to the weight member in a second direction that is opposite to the first direction.

[0008] In the clutch device according to the present invention, when a force is applied to the weight member such that the weight member rotates in a first direction about a center line of the weight member that is the center line of the weight member and extends in the axial direction of the output shaft, the rotation suppression mechanism of the centrifugal clutch mechanism applies a force to the weight member in a second direction that is opposite to the first direction. According to the above aspect, when the weight member held by the holding member moves in the radial direction, the rotation suppression mechanism suppresses the weight member from rotating in the circumferential direction. In other words, when the weight member moves in the radial direction, the rotation suppression mechanism suppresses vibration of the weight member and allows the weight member to move smoothly in the radial direction.

[0009] Another clutch device according to the present invention is a clutch device for transmitting or interrupting the rotational drive force of an input shaft to an output shaft, the clutch device comprising: a clutch center housed in a clutch housing that holds a plurality of input side rotating plates that are rotationally driven by the rotational drive of the input shaft and that is rotationally driven together with the output shaft; a pressure member that is provided so as to be able to approach or move away from the clutch center and to be rotatable relative to the clutch center, that holds at least some of the plurality of output side rotating plates that are arranged alternately with the input side rotating plates, and that is capable of pressing the input side rotating plates and the output side rotating plates; and a plurality of weight members that are configured to be movable from a radially inner position to an outer position by centrifugal force that accompanies rotation of the clutch housing, and that when the weight members are at the radially outer position, press the input side rotating plates against the output side rotating plates, making it possible to transmit the rotational drive force of the input shaft to the output shaft, and and a centrifugal clutch mechanism that can release the pressure contact force between the input side rotating plate and the output side rotating plate when the weight member is located at an inner position in the radial direction, thereby interrupting the transmission of the rotational driving force of the input shaft to the output shaft, wherein the centrifugal clutch mechanism comprises: a retaining member that holds the weight member movably between an inner position in the radial direction and an outer position in the radial direction; and a contact member that is arranged on the opposite side of the retaining member with the weight member interposed between them in the axial direction of the output shaft and that comes into contact with the weight member, wherein the retaining member has a retaining member-side inclined surface that is the center line of the weight member when the weight member is located at the inner position in the radial direction and that inclines toward the weight member with increasing distance from a center line extending in the axial direction of the output shaft, and the weight member has a weight member-side inclined surface that is contactable with the retaining member-side inclined surface and that inclines in a direction away from the retaining member with increasing distance from the center line in the circumferential direction.

[0010] According to another clutch device of the present invention, the weight member is sandwiched between a retaining member and a contact member, the retaining member having a retaining-member-side inclined surface that slopes toward the weight member as it moves away from the center line of the output shaft in the circumferential direction, and the weight member has a weight-member-side inclined surface that is contactable with the retaining-member-side inclined surface and slopes away from the retaining member as it moves away from the center line in the circumferential direction. According to this aspect, when the weight member held by the retaining member moves radially, the retaining-member-side inclined surface, the weight member-side inclined surface, and the contact member suppress circumferential rotation of the weight member. In other words, when the weight member moves radially, the retaining-member-side inclined surface, the weight member-side inclined surface, and the contact member suppress vibration of the weight member and allow the weight member to move smoothly in the radial direction.

[0011] According to the present invention, it is possible to provide a clutch device that suppresses vibration of the weight member and allows the weight member to move smoothly in the radial direction.

[0012] FIG. 1 is a cross-sectional view of a clutch device according to one embodiment. FIG. 2 is a perspective view of a first clutch center according to one embodiment. FIG. 3 is a perspective view of the first clutch center according to one embodiment. FIG. 4 is a perspective view of a second clutch center according to one embodiment. FIG. 5 is a plan view of the second clutch center according to one embodiment. FIG. 6 is a perspective view of a pressure member according to one embodiment. FIG. 7 is a perspective view of the pressure member according to one embodiment. FIG. 8A is a schematic diagram illustrating the functions of a center-side assist cam surface and a pressure-side assist cam surface. FIG. 8B is a schematic diagram illustrating the functions of a center-side slipper cam surface and a pressure-side slipper cam surface. FIG. 9 is a perspective view of a centrifugal clutch mechanism according to one embodiment, showing a state in which a weight member is positioned radially inward. FIG. 10 is a perspective view of a portion of the centrifugal clutch mechanism according to one embodiment. FIG. 11 is a front view of a portion of the centrifugal clutch mechanism according to one embodiment. FIG. 12 is a front view of a portion of the centrifugal clutch mechanism according to one embodiment. FIG. 13 is a perspective view of a retaining member according to one embodiment. Fig. 14 is a front view showing a holding member according to one embodiment. Fig. 15 is a perspective view showing a weight member according to one embodiment. Fig. 16 is a perspective view showing a weight member according to one embodiment. Fig. 17 is a perspective view showing a weight member and a spring according to one embodiment. Fig. 18 is a cross-sectional view taken along line XVIII-XVIII in Fig. 11.

[0013] Hereinafter, an embodiment of a clutch device according to the present invention will be described with reference to the drawings. It should be noted that the embodiment described here is not intended to limit the present invention in any way. Furthermore, the same reference numerals are used to designate components and parts that perform the same functions, and redundant descriptions will be omitted or simplified as appropriate.

[0014] 1 is a cross-sectional view of a clutch device 10 according to this embodiment. The clutch device 10 is provided, for example, in a saddle-ride type 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, which is the power source 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.

[0015] In the following description, the direction in which the pressure member 70 of the clutch device 10 approaches and moves away from the clutch center 40 is referred to as direction D, the direction in which the pressure member 70 approaches the clutch center 40 is referred to as a first direction D1, and the direction in which the pressure member 70 moves away from the clutch center 40 is referred to as a second direction D2. The circumferential direction (i.e., the rotational direction) of the clutch center 40 and the pressure member 70 is referred to as a circumferential direction S, the direction from one center-side cam portion 60 to the other center-side cam portion 60 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 referred to as a first circumferential direction S1 (see FIG. 2), and the direction from the other center-side cam portion 60 to one center-side cam portion 60 (the direction from the other pressure-side cam portion 90 to one pressure-side cam portion 90) is referred to as a second circumferential direction S2 (see FIG. 2). The radial direction of the output shaft 15 is defined as the radial direction M. In this embodiment, the axial direction of the output shaft 15 is the same as the direction D. The pressure member 70 and the clutch center 40 rotate in a first circumferential direction S1 (i.e., the direction from the center-side assist cam surface 60A of one center-side cam portion 60 to the center-side slipper cam surface 60S). However, the above directions are merely defined for the convenience of explanation and do not limit the installation mode of the clutch device 10 or the present invention in any way.

[0016] As shown in FIG. 1, the clutch device 10 includes an output shaft 15, a plurality of input side rotating plates 20, a plurality of output side rotating plates 22, a clutch housing 30, a clutch center 40, a pressure member 70, a stopper plate 100, a centrifugal clutch mechanism 120, and an auxiliary clutch plate 180.

[0017] As shown in Figure 1, the output shaft 15 is a hollow shaft body. One end of the output shaft 15 rotatably supports an input gear 35 and a clutch housing 30 (described later) via a needle bearing 28A. The output shaft 15 fixedly supports a clutch center 40 via a nut 28B. 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.

[0018] As shown in Figure 1, the output shaft 15 has a main body 15A extending in direction D. The main body 15A has an oil flow path 15H therein through which clutch oil flows. The oil flow path 15H is formed between the main body 15A and a sleeve 16C that fits onto the outside of a push rod 16A (described later). The clutch oil flows inside the output shaft 15, i.e., through the oil flow path 15H of the main body 15A.

[0019] As shown in FIG. 1 , the oil flow path 15H of the output shaft 15 includes a push rod 16A and a push member 16B adjacent to the push rod 16A. The push rod 16A and the push member 16B are slidably disposed within a sleeve 16C. One end (the left end in the figure) of the push rod 16A is connected to a clutch operating lever (not shown) of the motorcycle. When the clutch operating lever is operated, the push rod 16A slides within the sleeve 16C and presses the push member 16B in the second direction D2. A portion of the push member 16B protrudes outward from the output shaft 15 (in this case, in the second direction D2) and is connected to a release bearing 18 provided on the pressure member 70. The sleeve 16C and the push member 16B are formed narrower than the inner diameter of the main body 15A, ensuring the flow of clutch oil within the oil flow path 15H.

[0020] The clutch housing 30 is formed by aluminum die-casting. The clutch housing 30 is formed in a cylindrical shape with a bottom. As shown in Figure 1, the clutch housing 30 has a bottom wall 31 formed in a substantially circular shape and a side wall 33 extending in the second direction D2 from an edge of the bottom wall 31. The clutch housing 30 holds a plurality of input side rotating plates 20.

[0021] As shown in Figure 1, an input gear 35 is provided on the bottom wall 31 of the clutch housing 30. The input gear 35 is fixed to the bottom wall 31 by a rivet 35B via a torque damper 35A. The input gear 35 meshes with a drive gear (not shown) that rotates when the input shaft of the engine is rotated. The input gear 35 rotates integrally with the clutch housing 30, independently of the output shaft 15.

[0022] The input side rotating plate 20 is rotationally driven by the rotational drive of the input shaft. As shown in Figure 1, the input side rotating plate 20 is held on the inner circumferential surface of the side wall 33 of the clutch housing 30. The input side rotating plate 20 is held by engaging with a notch 30C formed in the clutch housing 30. The input side rotating plate 20 is provided so as to be displaceable along the axial direction of the clutch housing 30 (i.e., direction D). The input side rotating plate 20 is provided so as to be rotatable integrally with the clutch housing 30.

[0023] The input side rotating plate 20 is a member that is pressed against the output side rotating plate 22. The input side rotating plate 20 is formed in an annular shape. The input side rotating plate 20 is formed by aluminum die-casting. Friction material (not shown) made of multiple pieces of paper is attached to the front and back surfaces of the input side rotating plate 20. Grooves several hundred microns deep are formed between the friction material to retain clutch oil.

[0024] As shown in FIG. 1 , the clutch center 40 is accommodated in the clutch housing 30. The clutch center 40 is arranged concentrically with the clutch housing 30. The clutch center 40 holds a plurality of output side rotating plates 22. The output side rotating plates 22 and the input side rotating plates 20 are arranged alternately in direction D. The clutch center 40 is driven to rotate together with the output shaft 15. The clutch center 40 includes a first clutch center 41 and a second clutch center 51. The first clutch center 41 and the second clutch center 51 are assembled to each other. The second clutch center 51 is positioned radially outward of the first clutch center 41. The second clutch center 51 is fitted onto the first clutch center 41.

[0025] As shown in Figure 2, the first clutch center 41 includes an output shaft holding portion 42, an annular base wall 43 located radially outside the output shaft holding portion 42 in the radial direction M, and a plurality of center side cam portions 60.

[0026] As shown in Fig. 1, the output shaft 15 is connected to the output shaft holding portion 42. As shown in Fig. 2, the output shaft holding portion 42 is formed in a cylindrical shape. An insertion hole 45 into which the output shaft 15 is inserted and spline-fitted is formed in the output shaft holding portion 42. The insertion hole 45 is formed to penetrate the output shaft holding portion 42. A plurality of fitting teeth 47 extending in the axial direction of the output shaft 15 (i.e., direction D) are formed on an inner wall 45A of the output shaft holding portion 42 that defines the insertion hole 45. The fitting teeth 47 fit with the output shaft 15.

[0027] The center-side cam portion 60 is formed in a trapezoidal shape with a cam surface made up of an inclined surface that constitutes an Assist & Slipper (registered trademark) mechanism that generates an assist torque, which is a force that increases the pressing force (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 reduces the pressing force (contact force) between the input-side rotating plate 20 and the output-side rotating plate 22, thereby transitioning to a half-clutch state. As shown in FIG. 2 , the center-side cam portion 60 is formed to protrude in the second direction D2 from the surface 43D2 on the second direction D2 side of the base wall 43. The center-side cam portions 60 are arranged at equal intervals in the circumferential direction S of the first clutch center 41. In this embodiment, the first clutch center 41 has three center-side cam portions 60, but the number of center-side cam portions 60 is not limited to three.

[0028] As shown in FIG. 2 , the center-side cam portion 60 is located radially outward of the output shaft holder 42 in the M direction. The center-side cam portion 60 has a center-side assist cam surface 60A (see also FIG. 3 ) and a center-side slipper cam surface 60S. The center-side assist cam surface 60A is configured to generate a force (here, a first direction D1) that moves the pressure member 70 toward the clutch center 40 when the pressure member 70 rotates relative to the pressure member 70 during acceleration or other such events in order to increase the pressing force (pressure contact force) between the input side rotating plate 20 and the output side rotating plate 22. In this embodiment, when the force is generated, the position of the pressure member 70 relative to the clutch center 40 does not change, and the pressure member 70 does not need to physically approach the clutch center 40. Note that the pressure member 70 may be physically displaced relative to the clutch center 40. The center-side slipper cam surface 60S is configured to move the pressure member 70 away from the clutch center 40 when it rotates relative to the pressure member 70 during deceleration, etc., in order to reduce the pressing force (pressure contact force) between the input-side rotating plate 20 and the output-side rotating plate 22. In the center-side cam portions 60 adjacent to each other in the circumferential direction S, the center-side assist cam surface 60A of one center-side cam portion 60L and the center-side slipper cam surface 60S of the other center-side cam portion 60M are arranged opposite each other in the circumferential direction S.

[0029] As shown in FIG. 2 , the first clutch center 41 has multiple boss portions 62 (three in this embodiment). The boss portions 62 are components that indirectly hold the pressure member 70. The multiple boss portions 62 are arranged at equal intervals in the circumferential direction S. The boss portions 62 are formed in a cylindrical shape. The boss portions 62 are located radially outward of the output shaft holding portion 42 in the radial direction M. The boss portions 62 extend toward the pressure member 70 (i.e., toward the second direction D2). The boss portions 62 are provided on the center-side cam portion 60. The boss portions 62 are provided between the center-side assist cam surface 60A and the center-side slipper cam surface 60S in the circumferential direction S. A threaded hole 62H is formed in the boss portion 62, into which the bolt 28 (see FIG. 1 ) is inserted. The threaded hole 62H extends in the axial direction of the clutch center 40 (i.e., direction D).

[0030] 2 and 3, the first clutch center 41 has a center-side cam hole 43H that penetrates a portion of the base wall 43. The center-side cam hole 43H penetrates the base wall 43 in direction D. The center-side cam hole 43H extends in the radial direction M from the side of the output shaft holding portion 42. The center-side cam hole 43H is located between adjacent center-side cam portions 60 in the circumferential direction S. When viewed axially of the clutch center 40, the center-side assist cam surface 60A and a portion of the center-side cam hole 43H overlap.

[0031] 2, the first clutch center 41 has a plurality of engagement grooves 49. The engagement grooves 49 are formed on the outer peripheral surface of the base wall 43. The engagement grooves 49 are recessed from the outer peripheral surface of the base wall 43 toward the inside in the radial direction M.

[0032] 4, the second clutch center 51 includes an annular outer peripheral wall 52, a flange 68 extending radially outward from the outer peripheral wall 52 in the radial direction M, and a center-side fitting portion 54. The second clutch center 51 holds an input side rotating plate 20 and a plurality of output side rotating plates 22 arranged alternately in the direction D. The flange 68 is configured to be able to press the input side rotating plate 20 and the output side rotating plate 22.

[0033] As shown in FIG. 4 , a spline fitting portion 56 is provided on the outer peripheral surface of the outer peripheral wall 52. The spline fitting portion 56 has a plurality of center-side fitting teeth 57 extending along the outer peripheral surface of the outer peripheral wall 52 in the axial direction of the second clutch center 51 (i.e., direction D), a plurality of spline grooves 58 formed between adjacent center-side fitting teeth 57 and extending in the axial direction of the second clutch center 51 (i.e., direction D), and an oil discharge hole 59. The center-side fitting teeth 57 hold the output-side rotating plate 22. The center-side fitting teeth 57 are aligned in the circumferential direction S. The center-side fitting teeth 57 are formed at equal intervals in the circumferential direction S. The center-side fitting teeth 57 are formed with the same shape. The center-side fitting teeth 57 protrude outward in the radial direction M from the outer peripheral surface of the outer peripheral wall 52. The oil discharge hole 59 is formed to penetrate the outer peripheral wall 52 in the radial direction M. The oil discharge holes 59 are formed between adjacent center-side fitting teeth 57. That is, the oil discharge holes 59 are formed in the spline grooves 58. The oil discharge holes 59 are formed in the center-side fitting portion 54. The oil discharge holes 59 communicate between the inside and outside of the second clutch center 51. The oil discharge holes 59 are holes that discharge clutch oil and the like that has flowed into the clutch center 40 from the output shaft 15 to the outside of the clutch center 40. The clutch oil discharged from the oil discharge holes 59 is supplied to the input-side rotating plate 20 and the output-side rotating plate 22 that are located outside the oil discharge holes 59 in the radial direction M.

[0034] The output side rotating plate 22 is held by the spline fitting portion 56 of the second clutch center 51 and the pressure member 70. A portion of the output side rotating plate 22 is held by the center side fitting teeth 57 and the spline grooves 58 of the second clutch center 51 through spline fitting. Another portion of the output side rotating plate 22 is held by pressure side fitting teeth 87 (see FIG. 6 ) of the pressure member 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 (i.e., direction D). The output side rotating plate 22 is provided so as to be rotatable integrally with the clutch center 40. The output side rotating plate 22 is provided so as to be displaceable along the axial direction of the pressure member 70 (i.e., direction D). The output side rotating plate 22 is provided so as to be rotatable integrally with the pressure member 70.

[0035] The output side rotating plate 22 is a member that is pressed against the input side rotating plate 20. The output side rotating plate 22 is formed in an annular shape. The output side rotating plate 22 is formed by punching out an SPCC thin plate into an annular shape. The friction material provided on the input side rotating plate 20 may be provided on the output side rotating plate 22 instead of the input side rotating plate 20, or may be provided on both the input side rotating plate 20 and the output side rotating plate 22.

[0036] As shown in Figure 4, the center-side fitting portion 54 is formed on the inner peripheral surface of the outer peripheral wall 52. The center-side fitting portion 54 is configured to slidably fit onto a pressure-side fitting portion 88 (see Figure 6), which will be described later. The inner diameter of the center-side fitting portion 54 is formed with a fitting tolerance that allows the flow of clutch oil flowing out from the tip end 15T (see Figure 1) of the output shaft 15 relative to the pressure-side fitting portion 88. In other words, a gap is formed between the center-side fitting portion 54 and the pressure-side fitting portion 88.

[0037] 4 and 5, the second clutch center 51 has a plurality of engagement protrusions 55. The engagement protrusions 55 engage with the engagement grooves 49 (see FIG. 2) of the first clutch center 41. The engagement protrusions 55 are formed on the inner peripheral surface of the outer peripheral wall 52. The engagement protrusions 55 protrude inward in the radial direction M from the inner peripheral surface of the outer peripheral wall 52.

[0038] As shown in FIG. 1 , the pressure member 70 is provided so as to be able to move toward or away from the clutch center 40 and to rotate relative thereto. The pressure member 70 is configured to be able to press the input side rotating plate 20 and the output side rotating plate 22. The pressure member 70 is disposed concentrically with the clutch center 40 and the clutch housing 30. The pressure member 70 is fitted into the second clutch center 51, thereby positioning the pressure member 70 in the radial direction M. The pressure member 70 is provided so as to be able to slide relative to the first clutch center 41 and the second clutch center 51 in the direction D. The pressure member 70, the first clutch center 41, and the second clutch center 51 are configured so as to be able to rotate relative to one another in the circumferential direction S. As shown in FIG. 6 , the pressure member 70 has a main body 72 and a flange 98 connected to the outer circumferential edge of the main body 72 on the second direction D2 side and extending outward in the radial direction M. The main body 72 protrudes in the first direction D1 beyond the flange 98. The flange 98 is located at the outer diameter end of the pressure member 70. The flange 98 is located further outward in the radial direction M than a cylindrical portion 80 (see also FIG. 7 ), which will be described later. The pressure member 70 holds at least a portion of the input side rotating plates 20 and the multiple output side rotating plates 22 that are arranged alternately. The flange 98 is configured to be able to press the input side rotating plates 20 and the output side rotating plates 22.

[0039] As shown in FIG. 6, 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 FIG. 7).

[0040] The cylindrical portion 80 is formed in a cylindrical shape. The cylindrical portion 80 is formed integrally with the pressure-side cam portion 90. The cylindrical portion 80 accommodates the tip portion 15T (see FIG. 1) of the output shaft 15. The cylindrical portion 80 accommodates the release bearing 18 (see FIG. 1). The cylindrical portion 80 is a portion that receives the pressing force from the push member 16B. The cylindrical portion 80 is a portion that receives the clutch oil that flows out from the tip portion 15T of the output shaft 15.

[0041] As shown in FIG. 6 , the pressure-side cam portion 90 is formed in a platform shape having a cam surface made up of an inclined surface that constitutes an Assist & Slipper (registered trademark) mechanism that slides on the center-side cam portion 60 to generate assist torque or slipper torque. The pressure-side cam portion 90 is formed to protrude in the first direction D1 beyond the flange 98. The pressure-side cam portions 90 are arranged at equal intervals in the circumferential direction S of the pressure member 70. In this embodiment, the pressure member 70 has three pressure-side cam portions 90, but the number of pressure-side cam portions 90 is not limited to three.

[0042] As shown in FIG. 6 , the pressure-side cam portion 90 is located radially outward of the cylindrical portion 80 in the M direction. The pressure-side cam portion 90 has a pressure-side assist cam surface 90A (see also FIG. 7 ) and a pressure-side slipper 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 a direction from the pressure member 70 toward the clutch center 40 (here, the first direction D1) to increase the pressing force (pressure contact force) between the input-side rotating plate 20 and the output-side rotating plate 22 when rotating relative to the clutch center 40 during acceleration, etc. The pressure-side slipper cam surface 90S is configured to be able to contact the center-side slipper cam surface 60S. The pressure-side slipper cam surface 90S is configured to move the pressure member 70 away from the clutch center 40 when the pressure member 70 rotates relative to the clutch center 40 during deceleration or the like in order to reduce the pressing force (pressure contact force) between the input-side rotating plate 20 and the output-side rotating plate 22. In the pressure-side cam portions 90 adjacent to each other in the circumferential direction S, the pressure-side assist cam surface 90A of one pressure-side cam portion 90L and the pressure-side slipper cam surface 90S of the other pressure-side cam portion 90M are arranged opposite each other in the circumferential direction S.

[0043] 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 member 70, as shown in Figure 8A. 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 member 70, increasing the pressing force between the input-side rotating plate 20 and the output-side rotating plate 22.

[0044] On the other hand, when the rotational speed of the output shaft 15 exceeds the rotational speed of the input gear 35 and the clutch housing 30 and back torque is generated, a rotational force in the first circumferential direction S1 is applied to the clutch center 40, as shown in Fig. 8B. Therefore, the action of the center-side slipper cam surface 60S and the pressure-side slipper cam surface 90S moves the pressure member 70 in the second direction D2, releasing the pressure contact force between the input-side rotating plate 20 and the output-side rotating plate 22. This makes it possible to avoid problems with the engine and transmission due to back torque.

[0045] 6, the pressure-side fitting portion 88 is located radially outward of the pressure-side cam portion 90 in the radial direction M. The pressure-side fitting portion 88 is located closer to the second direction D2 than the pressure-side cam portion 90. The pressure-side fitting portion 88 is configured to be slidably fitted into the center-side fitting portion 54 (see FIG. 4).

[0046] As shown in FIGS. 6 and 7 , the pressure member 70 has a pressure-side cam hole 83H that penetrates a portion of the main body 72 and the flange 98. The pressure-side cam hole 83H is located radially outward of the cylindrical portion 80. The pressure-side cam hole 83H extends radially M from a side of the cylindrical portion 80 to a position radially outward of the pressure-side fitting portion 88. The pressure-side cam hole 83H is formed between the pressure-side assist cam surface 90A and the pressure-side slipper cam surface 90S of adjacent pressure-side cam portions 90. When viewed axially of the pressure member 70, the pressure-side assist cam surface 90A and a portion of the pressure-side cam hole 83H overlap. The boss portion 62 (see FIG. 2 ) of the first clutch center 41 is inserted into the pressure-side cam hole 83H. The boss portion 62 passes through the pressure-side cam hole 83H.

[0047] As shown in FIG. 6 , the pressure member 70 has a plurality of pressure-side fitting teeth 87 arranged on a flange 98. The pressure-side fitting teeth 87 hold at least a portion of the output-side rotating plate 22. The pressure-side fitting teeth 87 protrude from the flange 98 in the first direction D1. The pressure-side fitting teeth 87 are located radially outward from the cylindrical portion 80 in the radial direction M. The pressure-side fitting teeth 87 are located radially outward from the pressure-side cam portion 90 in the radial direction M. The pressure-side fitting teeth 87 are located radially outward from the pressure-side fitting portion 88 in the radial direction M. The plurality of pressure-side fitting teeth 87 are aligned in the circumferential direction S. The plurality of pressure-side fitting teeth 87 are arranged at equal intervals in the circumferential direction S. In this embodiment, some of the pressure-side fitting teeth 87 have been removed, which increases the spacing between those portions, but the remaining adjacent pressure-side fitting teeth 87 are arranged at equal intervals. As shown in Fig. 1, the pressure-side fitting teeth 87 hold an end plate 21. The end plate 21 is a plate used to adjust the spacing in direction D between the input-side rotating plate 20 and the output-side rotating plate 22 (i.e., the spacing in the axial direction of the output shaft 15) when a weight member 130 (described later) of the centrifugal clutch mechanism 120 is located at an inner position in the radial direction M.

[0048] As shown in Figure 7, the spring accommodating portion 84 is formed in the pressure-side cam portion 90. The spring accommodating portion 84 is located radially outward of the cylindrical portion 80. 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 a circular shape. The spring accommodating portion 84 accommodates the clutch spring 25.

[0049] As shown in FIG. 1 , the clutch spring 25 is housed in the spring housing 84. An end 25D1 of the clutch spring 25 in the first direction D1 abuts against the pressure member 70. An end 25D2 of the clutch spring 25 in the second direction D2 abuts against the stopper plate 100. The clutch spring 25 biases the pressure member 70 toward the clutch center 40 (i.e., toward the first direction D1). The clutch spring 25 is, for example, a coil spring made of spring steel wound in a spiral shape. The clutch spring 25 extends in the direction D.

[0050] As shown in FIG. 1 , the centrifugal clutch mechanism 120 is provided within the clutch housing 30. The centrifugal clutch mechanism 120 is provided on the first direction D1 side of the clutch center 40. The centrifugal clutch mechanism 120 is held in the clutch housing 30. The centrifugal clutch mechanism 120 is provided to be rotatable integrally with the clutch housing 30. As shown in FIG. 9 , the centrifugal clutch mechanism 120 includes a plurality of weight members 130, a holding member 140, a pressure contact member 150, a spring 160 (see FIG. 10 ), a contact member 170 (see also FIG. 11 ), and a rotation suppression mechanism 190 (see FIG. 18 ). When the weight members 130 are located at the outer side in the radial direction M (see FIG. 1 ), the centrifugal clutch mechanism 120 presses the input side rotating plate 20 and the output side rotating plate 22 together, enabling transmission of the rotational driving force of the input shaft to the output shaft 15. When the weight member 130 is positioned on the inside in the radial direction M (see FIG. 9), the centrifugal clutch mechanism 120 releases the pressure contact force between the input side rotating plate 20 and the output side rotating plate 22, thereby blocking the transmission of the rotational driving force of the input shaft to the output shaft 15. The centrifugal clutch mechanism 120 is configured to be able to press the auxiliary clutch plate 180 (see FIG. 1). Note that reference numeral 15C in FIGS. 9 to 14 indicates the axis of the output shaft 15.

[0051] As shown in Figure 12, the holding member 140 holds the weight member 130 movably between an inner position in the radial direction M and an outer position in the radial direction M. The holding member 140 is formed in a ring shape. The holding member 140 is formed by aluminum die-casting. The holding member 140 includes a main body 141, a plurality of engaging claws 143, a plurality of accommodating recesses 145, and a pressing portion 149 (see Figure 1). Note that Figures 10 to 12 show a state in which the weight member 130 is located on the inner side in the radial direction M.

[0052] 13, the main body 141 is formed in a ring shape. An insertion hole 141H is formed in the center of the main body 141, into which the output shaft 15 (see FIG. 1) is inserted.

[0053] As shown in Figure 14, the engagement claws 143 protrude outward in the radial direction M from the outer peripheral edge 141E of the main body 141. The engagement claws 143 are formed integrally with the main body 141. A surface 143D2 of the engagement claws 143 on the second direction D2 side and a surface 141D2 of the main body 141 on the second direction D2 side are formed flush with each other. The engagement claws 143 engage with the clutch housing 30 (see Figure 1). The multiple engagement claws 143 are aligned in the circumferential direction S.

[0054] As shown in Fig. 1 , the accommodating recess 145 is formed in the main body 141 so as to be recessed in the axial direction of the output shaft 15 (i.e., direction D). The accommodating recess 145 is recessed in a first direction D1. The accommodating recess 145 accommodates the weight member 130 so as to be movable in the radial direction M. As shown in Fig. 14 , the multiple accommodating recesses 145 are aligned in the circumferential direction S.

[0055] As shown in FIGS. 13 and 14 , the accommodating recess 145 is provided with a retaining member-side inclined surface 144 along which the weight member 130 slides when the weight member 130 moves in the radial direction M. The retaining member-side inclined surface 144 defines the accommodating recess 145. As shown in FIG. 18 , the retaining member-side inclined surface 144 inclines toward the weight member 130 (here, toward the second direction D2) as it moves away from a center line 130CL (described later) of the weight member 130 in the circumferential direction S when the weight member 130 is positioned radially inward (see FIG. 11 ). The retaining member-side inclined surface 144 is flat. The retaining member-side inclined surface 144 may also be curved. In this case, the curvature may be uniform or non-uniform. The retaining member-side inclined surface 144 includes a first retaining member-side inclined surface 144A and a second retaining member-side inclined surface 144B. The first retaining member-side inclined surface 144A is located on one side in the circumferential direction S (here, the first circumferential direction S1 side) of the center line 130CL when the weight member 130 is located radially inward. The second retaining member-side inclined surface 144B is located on the other side in the circumferential direction S (here, the second circumferential direction S2 side) of the center line 130CL when the weight member 130 is located radially inward. The inclination angles of the first retaining member-side inclined surface 144A and the second retaining member-side inclined surface 144B are the same, but may be different. In this embodiment, the first retaining member-side inclined surface 144A and the second retaining member-side inclined surface 144B are both flat, but they may both be curved, or one may be flat and the other curved.

[0056] As shown in FIG. 11 , the accommodation recess 145 has an accommodation groove 146 that accommodates a portion of the spring 160. The accommodation groove 146 defines the accommodation recess 145. The accommodation groove 146 extends in the radial direction M. The accommodation groove 146 is located between the first holding member side inclined surface 144A and the second holding member side inclined surface 144B in the circumferential direction S. As shown in FIG. 18 , the accommodation groove 146 is located closer to the first direction D1 than the first holding member side inclined surface 144A and the second holding member side inclined surface 144B. The accommodation groove 146 provides a gap 138 between the weight member 130 and the holding member 140. The gap 138 is located between the first holding member side inclined surface 144A and the second holding member side inclined surface 144B in the circumferential direction S and between a first weight member side inclined surface 133A and a second weight member side inclined surface 133B (described later). As shown in FIG. 11 , one end of a spring 160 abuts against an outer end 145X of the accommodating recess 145 in the radial direction M.

[0057] As shown in FIG. 9 , the multiple weight members 130 are arranged in the circumferential direction S. The weight members 130 are configured to be movable from an inner position to an outer position in the radial direction M due to centrifugal force generated by rotation of the clutch housing 30. The weight members 130 are configured to be able to press the pressure contact member 150 in the second direction D2. As shown in FIG. 10 , when no centrifugal force is applied, the weight members 130 are held at an inner position in the radial direction M by the springs 160. As shown in FIG. 1 , when centrifugal force is applied, the weight members 130 move outward in the radial direction M against the biasing force of the springs 160, and move to an outer position in the radial direction M. The weight members 130 are held by the holding member 140 so as to be movable between an inner position in the radial direction M and an outer position in the radial direction M. The weight members 130 are housed in the housing recesses 145 of the holding member 140. As shown in Figures 15 and 16, the weight member 130 comprises a spring holding portion 131, a weight member side inclined surface 133 located to the side of the spring holding portion 131, a weight side contact surface 130F (see Figure 15) located on the opposite side of the weight member side inclined surface 133 in the axial direction (i.e., direction D) of the output shaft 15, and a step portion 135 located to the side of the weight side contact surface 130F.

[0058] As shown in Figure 17, the spring retaining portion 131 retains the spring 160. The spring retaining portion 131 is a recessed groove that extends in the radial direction M and is recessed in the second direction D2. The spring retaining portion 131 includes a retaining wall 132 that retains the inner end of the spring 160 in the radial direction M. In this embodiment, two spring retaining portions 131 are aligned in the circumferential direction S. The spring retaining portion 131 is located between a first weight member side inclined surface 133A and a second weight member side inclined surface 133B, which will be described later, in the circumferential direction S. The spring retaining portion 131 is an example of a recess that accommodates the spring 160.

[0059] The weight member-side inclined surface 133 slides against the holding member-side inclined surface 144 (see FIG. 13 ) of the holding member 140 when the weight member 130 moves in the radial direction M. The weight member-side inclined surface 133 comes into contact with the holding member-side inclined surface 144. As shown in FIG. 18 , the weight member-side inclined surface 133 inclines in a direction away from the holding member 140 (here, in the second direction D2) as it moves away from the center line 130CL of the weight member 130 in the circumferential direction S. The weight member-side inclined surface 133 is flat. However, the weight member-side inclined surface 133 may be a curved surface. In this case, the curvature may be uniform or non-uniform. The weight member-side inclined surface 133 includes a first weight member-side inclined surface 133A and a second weight member-side inclined surface 133B. The first weight member-side inclined surface 133A is arranged to be able to come into contact with the first holding member-side inclined surface 144A. The first weight member-side inclined surface 133A is located on one side of the center line 130CL in the circumferential direction S (here, the first circumferential direction S1 side). The first weight member-side inclined surface 133A is located on the first circumferential direction S1 side of the spring holding portion 131. The second weight member-side inclined surface 133B is arranged to be able to come into contact with the second holding member-side inclined surface 144B. The second weight member-side inclined surface 133B is located on the other side of the center line 130CL in the circumferential direction S (here, the second circumferential direction S2 side). The second weight member-side inclined surface 133B is located on the second circumferential direction S2 side of the spring holding portion 131. The inclination angles of the first weight member-side inclined surface 133A and the second weight member-side inclined surface 133B are the same, but may be different. In this embodiment, the first weight member-side inclined surface 133A and the second weight member-side inclined surface 133B are both flat, but they may both be curved, or one may be flat and the other curved.

[0060] 1 , the weight-side contact surface 130F is provided so as to be able to come into contact with the pressing member 150. The weight-side contact surface 130F is inclined with respect to the axial direction of the output shaft 15 (i.e., direction D). The weight-side contact surface 130F is inclined so as to face in a first direction D1 from the inner side in the radial direction M toward the outer side in the radial direction M. The weight-side contact surface 130F is configured so as to be able to slide against a pressing-side contact surface 150F of the pressing member 150, which will be described later.

[0061] As shown in Fig. 15, the step portion 135 is located closer to the first direction D1 than the weight-side contact surface 130F. The step portion 135 is provided closer to the first circumferential direction S1 than the weight-side contact surface 130F and closer to the second circumferential direction S2 than the weight-side contact surface 130F. As shown in Fig. 11, when the contact member 170 is attached to the holding member 140, the step portion 135 overlaps the contact member 170.

[0062] As shown in FIG. 12 , the spring 160 is disposed on the outer side of the weight member 130 in the radial direction M. The spring 160 is provided on the holding member 140. The spring 160 is housed in the housing recess 145 of the holding member 140. More specifically, the spring 160 is housed in the housing groove 146. A portion of the spring 160 is located inside the weight member 130. That is, a portion of the spring 160 is located inside the spring holding portion 131 (see FIG. 17 ). The spring 160 biases the weight member 130 inward in the radial direction M. The spring 160 is, for example, a coil spring. In this embodiment, two springs 160 are arranged side by side in the circumferential direction S.

[0063] As shown in FIG. 1 , the contact member 170 is disposed between the holding member 140 and the pressure contact member 150. The contact member 170 is disposed on the opposite side of the holding member 140 with the weight member 130 sandwiched between them in the axial direction (direction D) of the output shaft 15. As shown in FIG. 11 , the contact member 170 is formed in a disk shape. The contact member 170 is fixed to the holding member 140. More specifically, the contact member 170 is fixed to the holding member 140 by fastening bolts 172 into bolt holes 140H (see FIG. 13 ) formed in the holding member 140. Note that the means for fixing the contact member 170 to the holding member 140 is not limited to the bolts 172. Instead of the bolts 172, the contact member 170 may be fixed to the holding member 140 by other fixing means, such as rivets. The contact member 170 comes into contact with the weight member 130. More specifically, the contact member 170 comes into contact with the stepped portion 135 of the weight member 130. The contact member 170 is a member that suppresses movement of the weight member 130 in the second direction D2. The contact member 170 has a plurality of openings 170H that are aligned in the circumferential direction S. The weight-side contact surface 130F of the weight member 130 is exposed to the outside through the openings 170H.

[0064] The pressing member 150 is configured to be able to move in the axial direction of the output shaft 15 (here, the second direction D2) as the weight member 130 moves from an inner position in the radial direction M to an outer position, thereby pressing the input side rotating plate 20 and the output side rotating plate 22 together. The pressing member 150 is formed in a ring shape. As shown in FIG. 1 , the pressing member 150 has a pressing-side contact surface 150F and a pressing surface 150P. The pressing-side contact surface 150F is configured to be able to come into contact with the weight member 130. The pressing-side contact surface 150F is inclined with respect to the axial direction of the output shaft 15 (i.e., direction D). The pressing-side contact surface 150F is inclined from the inner side in the radial direction M toward the outer side in the radial direction M in the first direction D1. The pressing-side contact surface 150F is configured to be able to slide relative to the weight-side contact surface 130F of the weight member 130. A plurality of pressure-contact-side contact surfaces 150F are provided for each weight member 130 along the circumferential direction S. When the clutch housing 30 rotates and centrifugal force is applied to the weight member 130, the weight member 130 moves along the pressure-contact-side contact surface 150F, causing the pressure member 150 to move in a direction away from the holding member 140 (i.e., the second direction D2). As a result, the pressing surface 150P of the pressure member 150 presses the flange 68 of the second clutch center 51 in the second direction D2. As shown in FIG. 9 , the pressure member 150 has a plurality of engaging protrusions 153 formed along the circumferential direction S. The engaging protrusions 153 overlap with the engaging claws 143 of the holding member 140. The engaging protrusions 153 engage with the clutch housing 30. The holding member 140 and the pressure contact member 150 are held by engaging with a notch 30C (see FIG. 1) formed in the clutch housing 30. The holding member 140 and the pressure contact member 150 are provided so as to be displaceable along the axial direction of the clutch housing 30 (i.e., direction D). The holding member 140 and the pressure contact member 150 are provided so as to be rotatable integrally with the clutch housing 30.

[0065] As shown in FIG. 12 , the rotation suppression mechanism 190 (see FIG. 18 ) is configured to apply a force to the weight member 130 in a second direction H2, which is the opposite direction to the first direction H1, when a force is applied to the weight member 130 such that the weight member 130 rotates in a first direction H1 around a center line 130CL of the weight member 130 that is the center line 130CL of the weight member 130 and extends in the axial direction of the output shaft 15 (direction D in this case). Note that in the example shown in FIG. 12 , the first direction H1 is clockwise and the second direction H2 is counterclockwise, but the first direction H1 may be counterclockwise and the second direction H2 may be clockwise. That is, when the weight member 130 moves in the radial direction M, forces in the clockwise and counterclockwise directions around the center line 130CL may be applied to the weight member 130. The rotation suppression mechanism 190 includes a holding member-side inclined surface 144, a weight member-side inclined surface 133, and a contact member 170. In Figures 11 and 12, the center line 130CL extends in a direction perpendicular to the paper surface.

[0066] In this centrifugal clutch mechanism 120, as shown in Fig. 9, when no centrifugal force is applied to the weight member 130, the weight member 130 is held at an inner position in the radial direction M, and the pressing force between the input side rotating plate 20 and the output side rotating plate 22 is released. On the other hand, as shown in Fig. 1, when centrifugal force is applied to the weight member 130, the weight member 130 moves from an inner position to an outer position in the radial direction M. When the weight member 130 moves in the radial direction M, the weight-side contact surface 130F of the weight member 130 and the pressing-side contact surface 150F of the pressing member 150 slide against each other, and the weight-member-side inclined surface 133 and the holding member-side inclined surface 144 slide against each other. At this time, even if a force that rotates weight member 130 in first direction H1 about center line 130CL of weight member 130 is applied to weight member 130, rotation suppression mechanism 190 applies a force to weight member 130 in second direction H2, which is the opposite direction to first direction H1. More specifically, when a force that rotates weight member 130 in first direction H1 about center line 130CL of weight member 130 is applied to weight member 130, second weight member-side inclined surface 133B attempts to ride up onto second holding member-side inclined surface 144B, causing weight member 130 to move in second direction D2, but movement in second direction D2 is prevented by contact member 170. As a result, weight member 130 receives a reaction force from contact member 170, and a force in second direction H2, which is the opposite direction to first direction H1, is applied to weight member 130. Therefore, the weight member 130 does not rattle in the circumferential direction S, and can move smoothly in the radial direction M. The same applies when a force that rotates the weight member 130 in the second direction H2 about the center line 130CL of the weight member 130 is applied to the weight member 130. Furthermore, the pressing surface 150P of the pressing member 150 presses the input side rotating plate 20 and the output side rotating plate 22 via the flange 68 of the second clutch center 51, bringing them into a pressed-contact state, so that the rotational driving force of the input shaft can be transmitted to the output shaft 15. At the same time, the holding member 140 moves in the first direction D1, and the pressing portion 149 (see FIG. 1) of the holding member 140 presses the auxiliary clutch plate 180.

[0067] As shown in Fig. 1, the auxiliary clutch plate 180 is provided inside the clutch housing 30. The auxiliary clutch plate 180 is fixed to the output shaft 15. An insertion hole 180H is formed in the auxiliary clutch plate 180, into which the output shaft 15 is inserted and spline-fitted. The auxiliary clutch plate 180 is disposed on the first direction D1 side of a portion of the centrifugal clutch mechanism 120. The auxiliary clutch plate 180 is adjacent to the first clutch center 41.

[0068] The auxiliary clutch plate 180 is configured to be pressed by the centrifugal clutch mechanism 120 (here, the pressing portion 149 of the holding member 140) when the input side rotating plate 20 and the output side rotating plate 22 are in pressure contact with each other (i.e., when the weight member 130 of the centrifugal clutch mechanism 120 is located at an outer position in the radial direction M), thereby enabling the rotational driving force of the input shaft to be transmitted to the output shaft 15. The auxiliary clutch plate 180 is configured to be released from the pressure of the centrifugal clutch mechanism 120 (here, the pressing portion 149 of the holding member 140) when the pressure between the input side rotating plate 20 and the output side rotating plate 22 is released (i.e., when the weight member 130 is located at an inner position in the radial direction M), thereby blocking the transmission of the rotational driving force of the input shaft to the output shaft 15.

[0069] As shown in Fig. 1, the stopper plate 100 is provided so as to be able to come into contact with the pressure member 70. The stopper plate 100 is a member that prevents the pressure member 70 from moving away from the clutch center 40 by more than a predetermined distance in the second direction D2. The stopper plate 100 is fixed to the boss portion 62 of the first clutch center 41 by the bolt 28. With the clutch spring 25 disposed in the spring accommodating portion 84, the pressure member 70 is fixed to the clutch center 40 by tightening the bolt 28 to the boss portion 62 via the stopper plate 100. The stopper plate 100 is formed in a ring shape in a plan view.

[0070] As described above, according to the clutch device 10 of this embodiment, when a force is applied to the weight member 130 that causes the weight member 130 to rotate in a first direction H1 about the center line 130CL of the weight member 130 and the center line 130CL extending in the axial direction of the output shaft 15 (here, direction D), the rotation suppression mechanism 190 of the centrifugal clutch mechanism 120 applies a force to the weight member 130 in a second direction H2 that is the opposite direction to the first direction H1. According to the above aspect, when the weight member 130 held by the holding member 140 moves in the radial direction M, the rotation suppression mechanism 190 suppresses the weight member 130 from rotating in the circumferential direction S. In other words, when the weight member 130 moves in the radial direction M, the rotation suppression mechanism 190 suppresses vibration of the weight member 130 and allows the weight member 130 to move smoothly in the radial direction M.

[0071] In the clutch device 10 of this embodiment, the holding member 140 has a holding member-side inclined surface 144 that inclines toward the weight member 130 as it moves away in the circumferential direction S from a center line 130CL when the weight member 130 is positioned inside in the radial direction M, and the weight member 130 has a weight member-side inclined surface 133 that is contactable with the holding member-side inclined surface 144 and that inclines in a direction away from the holding member 140 as it moves away from the center line 130CL in the circumferential direction S. According to the above aspect, when the weight member 130 held by the holding member 140 moves in the radial direction M, the holding member-side inclined surface 144, the weight member-side inclined surface 133, and the contact member 170 suppress rotation of the weight member 130 in the circumferential direction S.

[0072] In the clutch device 10 of this embodiment, the holding member-side inclined surface 144 and the weight member-side inclined surface 133 are flat surfaces. According to the above aspect, rotation of the weight member 130 in the circumferential direction S is more reliably suppressed.

[0073] In the clutch device 10 of this embodiment, the retaining member-side inclined surface 144 and the weight member-side inclined surface 133 may be curved. According to the above aspect, the contact surface between the weight member 130 and the retaining member 140 is relatively small, so that the weight member 130 can move more smoothly in the radial direction M.

[0074] In the clutch device 10 of this embodiment, the weight member-side inclined surface 133 includes a first weight member-side inclined surface 133A that is contactable with the first holding member-side inclined surface 144A and is located on one side in the circumferential direction S (here, the first circumferential direction S1 side) of the center line 130CL, and a second weight member-side inclined surface 133B that is contactable with the second holding member-side inclined surface 144B and is located on the other side in the circumferential direction S (here, the second circumferential direction S2 side) of the center line 130CL. According to the above aspect, rotation of the weight member 130 in the circumferential direction S is more reliably suppressed.

[0075] In the clutch device 10 of this embodiment, a gap 138 is provided between the first holding member side inclined surface 144A and the second holding member side inclined surface 144B and between the first weight member side inclined surface 133A and the second weight member side inclined surface 133B in the circumferential direction S, and between the weight member 130 and the holding member 140. According to the above aspect, the contact surface between the weight member 130 and the holding member 140 is relatively small, so that the weight member 130 can move more smoothly in the radial direction M.

[0076] In the clutch device 10 of this embodiment, the weight member 130 has a spring retaining portion 131 that houses the spring 160 and is located between the first weight member-side inclined surface 133A and the second weight member-side inclined surface 133B in relation to the circumferential direction S. According to the above aspect, the weight member 130 can more reliably prevent rotation of the weight member 130 in the circumferential direction S while properly housing the spring 160.

[0077] In the clutch device 10 of this embodiment, the retaining member 140 has an accommodating recess 145 that accommodates the weight member 130, and the retaining member-side inclined surface 144 defines the accommodating recess 145. According to the above aspect, the weight member 130 is properly accommodated by the retaining member 140, and rotation of the weight member 130 in the circumferential direction S is more reliably suppressed.

[0078] In the clutch device 10 of this embodiment, the contact member 170 is fixed to the holding member 140. According to the above aspect, the contact member 170 and the holding member 140 can more reliably prevent the weight member 130 from moving in the axial direction of the output shaft 15 (here, direction D).

[0079] 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.

[0080] The retaining member side inclined surface 144 may be inclined in a direction away from the weight member 130 (here, the first direction D1) as it moves away in the circumferential direction S from the center line 130CL when the weight member 130 is positioned inside in the radial direction M, and the weight member side inclined surface 133 may be inclined in a direction toward the retaining member 140 (here, the first direction D1) as it moves away in the circumferential direction S from the center line 130CL of the weight member 130.

[0081] In the above-described embodiment, the center line 130CL of the weight member 130 is parallel to the axial direction of the output shaft 15, but it does not have to be parallel.

[0082] In the above-described embodiment, the weight member-side inclined surface 133 and the holding member-side inclined surface 144 are provided at the portions where the weight member 130 and the holding member 140 slide, respectively, but this is not limiting. For example, contact member-side inclined surfaces having the same configuration as the weight member-side inclined surface 133 and the holding member-side inclined surface 144 may be provided at the portions where the weight member 130 and the contact member 170 slide, respectively.

[0083] In the above-described embodiment, the pressure member 70 holds one output side rotary plate 22 , but it may hold a plurality of output side rotary plates 22 .

[0084] In the above-described embodiment, the pressure member 70 holds some of the output rotating plates 22, and the clutch center 40 (more specifically, the second clutch center 51) holds other parts of the output rotating plates 22. However, the present invention is not limited to this. For example, the pressure member 70 may hold all of the output rotating plates 22.

[0085] In the above-described embodiment, the clutch center 40 includes the first clutch center 41 and the second clutch center 51, but the first clutch center 41 and the second clutch center 51 may be formed integrally.

[0086] The technology disclosed herein can be applied to various types of clutch devices. In the above-described embodiment, the pressure member 70 holds a portion of the output rotary plate 22, but the technology can also be applied to a clutch device that includes a pressure member that does not hold the output rotary plate 22. The technology can also be applied to a clutch device that does not have an Assist & Slipper (registered trademark) mechanism.

[0087] 10 Clutch device 15 Output shaft 20 Input side rotating plate 22 Output side rotating plate 30 Clutch housing 40 Clutch center 70 Pressure member 120 Centrifugal clutch mechanism 130 Weight member 131 Spring holding portion (recess) 133 Weight member side inclined surface 133A First weight member side inclined surface 133B Second weight member side inclined surface 138 Gap 140 Holding member 145 Housing recess 144 Holding member side inclined surface 144A First holding member side inclined surface 144B Second holding member side inclined surface 150 Pressing member 160 Spring 170 Contact member

Claims

1. A clutch device that transmits or cuts off the rotational driving force of an input shaft to an output shaft, comprising: a clutch center that is housed in a clutch housing that holds a plurality of input side rotating plates that are rotationally driven by the rotational drive of the input shaft and that rotates together with the output shaft; a pressure member that is provided so as to be able to approach or move away from the clutch center and to be rotatable relative to the clutch center, that holds at least some of a plurality of output side rotating plates that are arranged alternately with the input side rotating plates, and that can press the input side rotating plates and the output side rotating plates; a centrifugal clutch mechanism having a plurality of weight members configured to be movable from a radially inner position to an outer position by centrifugal force accompanying rotation of the clutch housing, and which presses the input side rotating plate and the output side rotating plate together when the weight members are at the radially outer position, thereby enabling transmission of the rotational drive force of the input shaft to the output shaft, and which releases the pressing force between the input side rotating plate and the output side rotating plate when the weight members are at the radially inner position, thereby blocking transmission of the rotational drive force of the input shaft to the output shaft; wherein the centrifugal clutch mechanism comprises: a holding member that holds the weight members movably between the radially inner position and the radially outer position; and a rotation suppressing mechanism that, when a force is applied to the weight members such that the weight members rotate in a first direction around a center line of the weight members that is the center line of the weight members and extends in the axial direction of the output shaft, applies a force to the weight members in a second direction that is opposite to the first direction.

2. A clutch device as described in claim 1, wherein the centrifugal clutch mechanism has a contact member that is arranged on the opposite side of the retaining member with the weight member sandwiched between them in the axial direction of the output shaft and that comes into contact with the weight member, the retaining member having a retaining member-side inclined surface that inclines toward the weight member as it moves away circumferentially from the center line when the weight member is located radially inward, the weight member having a weight member-side inclined surface that is contactable with the retaining member-side inclined surface and that inclines in a direction away from the retaining member as it moves away circumferentially from the center line, and the rotation suppression mechanism includes the retaining member-side inclined surface, the weight member-side inclined surface, and the contact member.

3. A clutch device according to claim 2, wherein the retaining member side inclined surface and the weight member side inclined surface are flat surfaces.

4. A clutch device according to claim 2, wherein the retaining member side inclined surface and the weight member side inclined surface are curved surfaces.

5. A clutch device as described in claim 2, wherein the retaining member side inclined surface includes a first retaining member side inclined surface located on one side of the circumferential direction relative to the center line when the weight member is located radially inward, and a second retaining member side inclined surface located on the other side of the circumferential direction, and the weight member side inclined surface includes a first weight member side inclined surface that can come into contact with the first retaining member side inclined surface and that is located on one side of the center line in the circumferential direction, and a second weight member side inclined surface that can come into contact with the second retaining member side inclined surface and that is located on the other side of the center line in the circumferential direction.

6. A clutch device as described in claim 5, wherein a gap is provided between the first retaining member side inclined surface and the second retaining member side inclined surface and between the first weight member side inclined surface and the second weight member side inclined surface in the circumferential direction, and between the weight member and the retaining member.

7. A clutch device as described in claim 5, wherein the centrifugal clutch mechanism comprises a spring provided on the retaining member and biasing the weight member radially inward, and the weight member has a recess that houses the spring and is located between the first weight member side inclined surface and the second weight member side inclined surface in the circumferential direction.

8. A clutch device according to claim 2, wherein the retaining member has an accommodation recess that accommodates the weight member so that the weight member is movable in the radial direction, and the retaining member-side inclined surface defines the accommodation recess.

9. The clutch device according to claim 2, wherein said contact member is fixed to said retaining member.

10. A clutch device for transmitting or interrupting the rotational driving force of an input shaft to an output shaft, comprising: a clutch center accommodated in a clutch housing that holds a plurality of input side rotating plates that are rotationally driven by the rotational drive of the input shaft and that rotates together with the output shaft; a pressure member that is provided so as to be able to approach or move away from the clutch center and to be rotatable relative to the clutch center, that holds at least some of a plurality of output side rotating plates that are arranged alternately with the input side rotating plates, and that can press the input side rotating plates and the output side rotating plates; a centrifugal clutch mechanism having a plurality of weight members configured to be movable from a radially inner position to an outer position by centrifugal force accompanying rotation of the clutch housing, and which presses the input side rotating plate and the output side rotating plate together when the weight members are at the radially outer position, thereby enabling transmission of the rotational driving force of the input shaft to the output shaft, and which releases the pressing force between the input side rotating plate and the output side rotating plate when the weight members are at the radially inner position, thereby blocking transmission of the rotational driving force of the input shaft to the output shaft; the centrifugal clutch mechanism comprises: a holding member that holds the weight members movably between the radially inner position and the radially outer position; and a contact member that is arranged on the opposite side of the holding member with the weight members sandwiched between them in the axial direction of the output shaft, and that comes into contact with the weight members, the retaining member has a retaining member-side inclined surface that is inclined toward the weight member as it moves away from a center line that is the center line of the weight member when the weight member is located radially inward and that extends in the axial direction of the output shaft, and the weight member has a weight member-side inclined surface that is contactable with the retaining member-side inclined surface and that is inclined in a direction away from the retaining member as it moves away from the center line in the circumferential direction.

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