Clutch device

Abstract

A clutch device (10) is provided with: a clutch spring (25) that biases a pressure plate (70) in a first direction (D1); and a stopper plate (100) fixed to the clutch center section (40), the pressure plate (70) having a spring housing section (84) that houses the clutch spring (25) and that is disposed so as to be aligned with the pressure-side auxiliary cam surface (90A) in the rotation direction (S) of the pressure plate (70). The clutch spring (25) is provided with a reduction means (110) for reducing the restoring force in the direction from the clutch spring (25) toward the pressure-side auxiliary cam surface (90A) during the period from a state in which the center-side auxiliary cam surface (60A) and the pressure-side auxiliary cam surface (90A) are separated in the rotational direction (S) to a state in which the center-side auxiliary cam surface (60A) and the pressure-side auxiliary cam surface (90A) approach each other and come into contact with each other.

Description

Technical Field

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

[0002] In the past, vehicles such as motorcycles were equipped with clutch devices. For example, Patent Document 1 discloses a clutch device comprising: a clutch center portion that holds an output-side rotating plate; a pressure plate that is configured to be able to approach and separate from the clutch center portion; and a clutch spring that urges the pressure plate toward the clutch center portion. The clutch spring is housed in a housing formed in the pressure plate. One end of the clutch spring contacts the pressure plate, while the other end of the clutch spring contacts a stopper plate fixed to the clutch center portion. Furthermore, the clutch center portion and the pressure plate of the clutch device of Patent Document 1 each comprise a central-side auxiliary cam surface and a pressure-side auxiliary cam surface. When the engine's rotational drive force is capable of being transmitted to the output shaft, the central-side auxiliary cam surface and the pressure-side auxiliary cam surface generate a force in the direction from the pressure plate toward the clutch center portion, thereby increasing the pressing force on the input-side rotating plate and the output-side rotating plate.

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent No. 6894792 Summary of the Invention

[0006] [Problems to be Solved by the Invention]

[0007] However, when the clutch transitions from an engaged to a disengaged state—that is, from contact between the center-side assist cam surface and the pressure-side assist cam surface—to a disengaged state, the pressure plate moves away from the clutch center while rotating circumferentially relative to the clutch center. Consequently, the clutch spring housed in the housing may generate a restoring force directed toward the pressure-side assist cam surface (i.e., a restoring force intended to return the center-side assist cam surface to contact with the pressure-side assist cam surface). If this restoring force is excessive, the center-side assist cam surface and the pressure-side assist cam surface may suddenly contact each other during the transition from the disengaged to the engaged state, potentially causing the clutch to engage suddenly.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a clutch device that suppresses a sudden engagement of the clutch.

[0009] [Means for solving the problem]

[0010] The clutch device of the present invention is a clutch device for transmitting or cutting off the rotational driving force of the input shaft to the output shaft, wherein the clutch device comprises: a clutch central portion housed in a clutch housing that holds a plurality of input-side rotating plates that are rotated by the rotation of the input shaft and is rotated together with the output shaft; a pressure plate that is arranged to be able to approach or separate from the clutch central portion and to be able to rotate relatively, and holds a plurality of output-side rotating plates that are alternately arranged with the input-side rotating plates and can press the input-side rotating plates and the output-side rotating plates; a clutch spring that urges the pressure plate in the first direction when the direction in which the pressure plate approaches the clutch central portion is set as a first direction and the direction in which the pressure plate separates from the clutch central portion is set as a second direction; and a stopper plate that is fixed to the clutch central portion and restrains the pressure plate from separating from the clutch central portion in the second direction by more than a predetermined distance, the end of the clutch spring in the first direction contacts the pressure plate, and the end of the clutch spring in the second direction contacts the stopper The clutch center portion has a central side auxiliary cam surface, and the central side auxiliary cam surface generates a force from the pressure plate toward the clutch center portion in order to increase the pressing force of the input side rotating plate and the output side rotating plate when the clutch center portion rotates relative to the pressure plate. The pressure plate has: a pressure side auxiliary cam surface, which is configured to contact the central side auxiliary cam surface when the pressure plate rotates relative to the clutch center portion, and to generate a force from the pressure plate toward the clutch center portion in order to increase the pressing force of the input side rotating plate and the output side rotating plate; and a storage portion, which is arranged in an array with the pressure side auxiliary cam surface in the rotation direction of the pressure plate and stores the clutch spring, and the clutch device has a reducing unit, which reduces the restoring force in the clutch spring from the clutch spring toward the pressure side auxiliary cam surface during the period when the central side auxiliary cam surface and the pressure side auxiliary cam surface are separated in the rotation direction and approach each other and contact each other.

[0011] According to the clutch device of the present invention, the reducing unit reduces the restoring force of the clutch spring directed from the clutch spring toward the pressure-side assist cam surface during the period from the center-side assist cam surface and the pressure-side assist cam surface moving apart in the rotational direction to approaching and contacting each other. By reducing the restoring force that could otherwise be generated by the clutch spring, the reducing unit can prevent the center-side assist cam surface and the pressure-side assist cam surface from suddenly contacting due to the restoring force. In other words, the reducing unit can prevent the clutch from suddenly engaging.

[0012] The clutch assembly of claim 1, wherein the clutch assembly comprises a plurality of rotating plates which are arranged to rotate relative to the input shaft and the output shaft, the plurality of rotating plates being ... output shaft, the plurality of rotating plates being arranged to rotate relative The clutch center portion is in contact with the clutch center portion, and the clutch center portion has a central side auxiliary cam surface, and when the clutch center portion rotates relative to the pressure plate, a force is generated in the direction from the pressure plate toward the clutch center portion in order to increase the pressing force of the input side rotating plate and the output side rotating plate; and a storage portion is arranged in an array with the central side auxiliary cam surface in the rotation direction of the clutch center portion, and the clutch spring is stored, and the pressure plate has a pressure side auxiliary cam surface, and the pressure side auxiliary cam surface is configured to contact the central side auxiliary cam surface when the pressure plate rotates relative to the clutch center portion, and to increase the pressing force of the input side rotating plate and the output side rotating plate, a force is generated in the direction from the pressure plate toward the clutch center portion, and during the period from the central side auxiliary cam surface and the pressure side auxiliary cam surface being separated in the rotation direction to approaching and contacting each other, the restoring force in the clutch spring from the clutch spring toward the central side auxiliary cam surface is reduced.

[0013] According to another clutch device according to the present invention, the reducing unit reduces the restoring force in the clutch spring directed from the clutch spring toward the center-side assist cam surface during the period from the center-side assist cam surface and the pressure-side assist cam surface moving apart in the rotational direction to the point of approaching and contacting each other. By reducing the restoring force that could otherwise be generated by the clutch spring, the reducing unit can prevent the center-side assist cam surface and the pressure-side assist cam surface from suddenly contacting due to the restoring force. In other words, the reducing unit can prevent the clutch from suddenly engaging.

[0014] [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a clutch device that suppresses abrupt engagement of the clutch. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional view of the clutch device according to the first embodiment.

[0017] Figure 2 It is a perspective view of the clutch center portion according to the first embodiment.

[0018] Figure 3 It is a plan view of the central portion of the clutch according to the first embodiment.

[0019] Figure 4 It is a perspective view of the pressing plate according to the first embodiment.

[0020] Figure 5 It is a plan view of the press plate according to the first embodiment.

[0021] Figure 6 It is a perspective view of the pressing plate according to the first embodiment.

[0022] Figure 7 It is a plan view of the press plate according to the first embodiment.

[0023] Figure 8A This is a schematic diagram explaining the functions of the center-side auxiliary cam surface and the pressure-side auxiliary cam surface.

[0024] Figure 8B This is a schematic diagram explaining the functions of the center-side sliding cam surface and the pressure-side sliding cam surface.

[0025] Figure 9 It is a plan view showing a state in which the clutch spring according to the first embodiment is accommodated in the spring accommodation portion of the pressure plate.

[0026] Figure 10A It is a cross-sectional view showing the state of the clutch spring in a state where the clutch is disengaged.

[0027] Figure 10B It is a cross-sectional view showing the state of the clutch spring when the clutch is connected.

[0028] Figure 11A This is a cross-sectional view showing the state of the clutch spring in a state where the clutch is disengaged in the second embodiment.

[0029] Figure 11B This is a cross-sectional view showing the state of the clutch spring when the clutch is connected in the second embodiment.

[0030] Figure 12 It is a plan view showing a state in which the clutch spring according to the second embodiment is accommodated in the spring accommodation portion of the pressure plate.

[0031] Figure 13 It is a cross-sectional view of a clutch device according to a third embodiment.

[0032] Figure 14A It is a cross-sectional view showing the state of the clutch spring in a state where the clutch is disengaged.

[0033] Figure 14B It is a cross-sectional view showing the state of the clutch spring when the clutch is connected.

[0034] Figure 15A This is a cross-sectional view showing the state of the clutch spring in a state where the clutch is disengaged in the fourth embodiment.

[0035] Figure 15B This is a cross-sectional view showing the state of the clutch spring when the clutch is connected in the fourth embodiment. DETAILED DESCRIPTION

[0036] The following describes embodiments of the clutch device of the present invention with reference to the accompanying drawings. The embodiments described herein are not intended to limit the present invention. Components and parts that perform the same function are denoted by the same reference numerals, and any duplicate descriptions are omitted or simplified as appropriate.

[0037] <First embodiment>

[0038] Figure 1 This is a cross-sectional view of a clutch device 10 according to this embodiment. The clutch device 10 is provided on a vehicle such as a motorcycle. The clutch device 10 transmits or disconnects the rotational driving force of the input shaft (crankshaft) of the motorcycle's engine to the output shaft 15. The clutch device 10 transmits or disconnects the rotational driving force of the input shaft to the drive wheels (rear wheels) via the output shaft 15. The clutch device 10 is disposed between the engine and the transmission.

[0039] In the following description, the direction in which the pressure plate 70 of the clutch device 10 approaches and moves away from the clutch central portion 40 is referred to as direction D (an example of a moving direction), the direction in which the pressure plate 70 approaches the clutch central portion 40 is referred to as a first direction D1, and the direction in which the pressure plate 70 moves away from the clutch central portion 40 is referred to as a second direction D2. Furthermore, the rotational direction (i.e., the circumferential direction) of the clutch central portion 40 and the pressure plate 70 is referred to as a rotational direction S. With respect to the rotational direction S, the direction from one pressure-side cam portion 90 toward the other pressure-side cam portion 90 is referred to as a first rotational direction S1 (see Figure 5 ), the direction from the other pressure-side cam portion 90 toward the one pressure-side cam portion 90 is defined as the second rotation direction S2 (refer to Figure 5In this embodiment, the axial direction of the output shaft 15, the axial direction of the clutch housing 30, the axial direction of the clutch center 40, and the axial direction of the pressure plate 70 are the same as direction D. Furthermore, the pressure plate 70 and the clutch center 40 rotate in the first rotational direction S1. However, these directions are merely defined for ease of explanation and do not limit the configuration of the clutch device 10 or the present invention.

[0040] like Figure 1 As shown, the clutch device 10 includes an output shaft 15, an input-side rotating plate 20, an output-side rotating plate 22, a clutch housing 30, a clutch center 40, a pressure plate 70, a stopper plate 100, a clutch spring 25, and a lowering unit 110. The clutch device 10 is a so-called inner release type clutch device.

[0041] like Figure 1 As shown, the output shaft 15 is a hollow shaft. One end of the output shaft 15 rotatably supports the input gear 35 and the clutch housing 30 (described later) via a needle bearing 15A. The output shaft 15 securely supports the clutch center 40 via a nut 15B. In other words, the output shaft 15 rotates integrally with the clutch center 40. The other end of the output shaft 15 is connected to, for example, a transmission (not shown) of a motorcycle.

[0042] like Figure 1 As shown, the output shaft 15 includes a push rod 16A and a pressing member 16B disposed adjacent to the push rod 16A within its hollow portion 15H. The hollow portion 15H functions as a passage for clutch oil. Clutch oil flows within the output shaft 15, that is, within the hollow portion 15H. The push rod 16A and the pressing member 16B are configured to slide within the hollow portion 15H of the output shaft 15. One end of the push rod 16A (the left end in the figure) is connected to the clutch mechanism of the motorcycle (e.g., a clutch lever or operating button). When the driver operates the clutch, the push rod 16A slides within the hollow portion 15H and presses the pressing member 16B in the second direction D2. A portion of the pressing member 16B protrudes outward from the output shaft 15 (here, in the second direction D2) and is connected to the release bearing 18 disposed on the pressure plate 70. The push rod 16A and the pressing member 16B are formed to be smaller than the inner diameter of the hollow portion 15H, thereby ensuring the fluidity of the clutch oil in the hollow portion 15H.

[0043] The clutch housing 30 is formed of aluminum alloy. The clutch housing 30 is formed into a bottomed cylindrical shape. Figure 1 As shown, the clutch housing 30 includes 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 rotation plates 20.

[0044] like Figure 1 As 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 via a torque damper 35A and rivets 35B. The input gear 35 meshes with a drive gear (not shown) that is rotated by the rotation of the engine's input shaft. The input gear 35 is driven to rotate integrally with the clutch housing 30, independent of the output shaft 15.

[0045] The input side rotating plate 20 is driven to rotate by the rotation of the input shaft. Figure 1 As shown, the input-side rotating plate 20 is retained by the inner circumferential surface of the side wall 33 of the clutch housing 30. The input-side rotating plate 20 is retained by the clutch housing 30 through a splined fit. The input-side rotating plate 20 is displaceable along the axial direction of the clutch housing 30 (i.e., direction D). The input-side rotating plate 20 is rotatable integrally with the clutch housing 30.

[0046] The input-side rotating plate 20 is a component that presses against the output-side rotating plate 22. It is annular and formed by aluminum die-casting. Friction material (not shown) consisting of multiple paper sheets is affixed to the front and back surfaces of the input-side rotating plate 20. Grooves several hundred microns deep are formed between the friction materials to retain clutch oil.

[0047] like Figure 1 As shown, the clutch center 40 is housed in the clutch housing 30. The clutch center 40 is concentrically arranged with the clutch housing 30. The clutch center 40 includes a cylindrical main body 42 and a flange 68 extending radially outward from the outer periphery of the main body 42. The clutch center 40 holds a plurality of output-side rotating plates 22 that are alternately arranged with the input-side rotating plates 20 in direction D. The clutch center 40 is driven to rotate together with the output shaft 15.

[0048] like Figure 2 As 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 retaining portion 50 provided in the center of the base wall 43; and a plurality of central side cam portions 60 connected to the base wall 43 and the outer peripheral wall 45.

[0049] like Figure 2 As shown, the output shaft holding portion 50 is formed into a cylindrical shape. Figure 1 ) is inserted and splined into the insertion hole 51. The insertion hole 51 is formed through the base wall 43. The inner peripheral surface 50A of the output shaft holding portion 50 forming the insertion hole 51 is formed with a plurality of spline grooves along the axial direction. The output shaft holding portion 50 is connected to the output shaft 15 (see Figure 1 ).

[0050] like Figure 2 As shown, the outer peripheral wall 45 of the clutch center portion 40 is positioned radially outward from the output shaft retaining portion 50. A splined engagement portion 46 is provided on the outer peripheral surface of the outer peripheral wall 45. The splined engagement portion 46 includes a plurality of central engaging teeth 47 extending along the outer peripheral surface of the outer peripheral wall 45 in the axial direction of the clutch center portion 40; and a plurality of spline grooves 48 formed between adjacent central engaging teeth 47 and extending in the axial direction of the clutch center portion 40. The central engaging teeth 47 retain the output-side rotating plate 22. The plurality of central engaging teeth 47 are arranged along the rotational direction S. The plurality of central engaging teeth 47 are formed at equal intervals in the rotational direction S. The plurality of central engaging teeth 47 have the same shape. The central engaging teeth 47 protrude radially outward from the outer peripheral surface of the outer peripheral wall 45. The outer peripheral surface of the central engaging teeth 47 is formed to be substantially parallel to the axis of the output shaft 15.

[0051] The output side rotating plate 22 is held by the spline fitting portion 46 of the clutch center portion 40 and the pressure plate 70. A portion of the output side rotating plate 22 is held by the center side fitting teeth 47 and the spline grooves 48 of the clutch center portion 40 through spline fitting. The other portion of the output side rotating plate 22 is held by the pressure side fitting teeth 77 (see FIG. 1 ) described later on the pressure plate 70. Figure 4 The output side rotating plate 22 is provided so as to be displaceable along the axial direction of the clutch central portion 40 . The output side rotating plate 22 is provided so as to be rotatable integrally with the clutch central portion 40 .

[0052] The output-side rotating plate 22 is a component that presses against the input-side rotating plate 20. The output-side rotating plate 22 is formed into a ring shape. The output-side rotating plate 22 is formed by punching a thin plate made of SPCC material into a ring shape. Furthermore, 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.

[0053] like Figure 2 As shown, the central cam portion 60 is formed into a table shape having a cam surface. This cam surface is composed of an inclined surface that constitutes an assist & slide (registered trademark) mechanism. This assist slide mechanism generates an assist torque that increases the pressing force (pressing contact force) between the input side rotating plate 20 and the output side rotating plate 22, or a slide torque that causes the input side rotating plate 20 and the output side rotating plate 22 to separate earlier and shift to a semi-clutch state. The central cam portion 60 is formed to protrude from the base wall 43 in the second direction D2. Figure 3 As shown, the center cam portions 60 are arranged at equal intervals in the rotational direction S of the clutch center portion 40. In this embodiment, the clutch center portion 40 has three center cam portions 60, but the number of center cam portions 60 is not limited to three.

[0054] like Figure 3 As shown, the center-side cam portion 60 is located radially outward of the output shaft retaining portion 50. The center-side cam portion 60 includes a center-side auxiliary cam surface 60A and a center-side sliding cam surface 60S. The center-side auxiliary cam surface 60A is configured to generate a force in a direction (here, the first direction D1) from the pressure plate 70 toward the clutch center portion 40, increasing the pressing force (contact force) between the input-side rotating plate 20 and the output-side rotating plate 22 during relative rotation with respect to the pressure plate 70. In this embodiment, this force is generated without changing the position of the pressure plate 70 relative to the clutch center portion 40, and the pressure plate 70 does not need to be physically close to the clutch center portion 40. Alternatively, the pressure plate 70 may be physically displaced relative to the clutch center portion 40. The center-side sliding cam surface 60S is configured to reduce the pressing force (contact force) between the input-side rotating plate 20 and the output-side rotating plate 22 during relative rotation with respect to the pressure plate 70, thereby separating the pressure plate 70 from the clutch center portion 40. Of the center cam portions 60 adjacent to each other in the rotational direction S, the center auxiliary cam surface 60A of one center cam portion 60L and the center sliding cam surface 60S of the other center cam portion 60M are arranged to face each other in the rotational direction S.

[0055] like Figure 2 As shown, the clutch center portion 40 includes a plurality of (three in this embodiment) boss portions 54. The boss portion 54 supports the stopper plate 100 (see Figure 1 ) component. A plurality of boss portions 54 are arranged at equal intervals in the rotation direction S. The boss portion 54 is formed in a cylindrical shape. The boss portion 54 is located radially outward of the output shaft retaining portion 50. The boss portion 54 extends toward the pressure plate 70 (i.e., toward the second direction D2). The boss portion 54 is provided on the central side cam portion 60. The boss portion 54 is located between the central side auxiliary cam surface 60A and the central side sliding cam surface 60S in the rotation direction S. A threaded hole 54H is formed in the boss portion 54. The threaded hole 54H extends along the axial direction of the clutch central portion 40. A bolt 28 (refer to Figure 1 ).

[0056] like Figure 2 and Figure 3As shown, the clutch central portion 40 has a central cam hole 43H extending through a portion of the base wall 43. The central cam hole 43H extends from the side of the output shaft retaining portion 50 to the outer peripheral wall 45. The central cam hole 43H is formed between a central auxiliary cam surface 60A of one central cam portion 60 and a central sliding cam surface 60S of the other central cam portion 60. When viewed in the axial direction of the clutch central portion 40, the central auxiliary cam surface 60A partially overlaps with the central cam hole 43H.

[0057] like Figure 1 As shown, the pressure plate 70 is provided so as to be able to approach or separate from the clutch central portion 40 and to rotate relatively. The pressure plate 70 is configured to be able to press the input side rotating plate 20 and the output side rotating plate 22. The pressure plate 70 is arranged concentrically with the clutch central portion 40 and the clutch housing 30. The pressure plate 70 has a main body 72 and a flange 98 connected to the outer peripheral edge of the main body 72 on the second direction D2 side and extending radially outward. The main body 72 protrudes further in the first direction D1 than the flange 98. The flange 98 is located at the outer diameter end of the pressure plate 70. The flange 98 is located at a position larger than the cylindrical portion 80 described later (also refer to Figure 4 The pressure plate 70 holds the plurality of output-side rotating plates 22 arranged alternately with the input-side rotating plates 20. The flange 98 is configured to press the input-side rotating plates 20 and the output-side rotating plates 22.

[0058] like Figure 4 As shown, the main body 72 includes a cylindrical portion 80, a plurality of pressure-side cam portions 90, and a spring receiving portion 84 (see Figure 6 ). The spring housing portion 84 is an example of a housing portion.

[0059] 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 front end portion 15T of the output shaft 15 (see Figure 1 The release bearing 18 is housed in the cylindrical portion 80 (see 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 flows out from the front end portion 15T of the output shaft 15.

[0060] like Figure 4 As shown, the pressure side cam portion 90 is formed into a table shape having a cam surface, which is composed of an inclined surface that constitutes an assist & slide (registered trademark) mechanism that slides on the center side cam portion 60 to generate an assist torque or a slide torque. The pressure side cam portion 90 is formed to protrude in the first direction D1 from the flange 98. Figure 5As shown, the pressure-side cam portions 90 are arranged at equal intervals in the rotation direction S of the pressure plate 70. In the present embodiment, the pressure plate 70 has three pressure-side cam portions 90, but the number of pressure-side cam portions 90 is not limited to three.

[0061] like Figure 5 As 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 auxiliary cam surface 90A (also see Figure 6 and Figure 7 ) and a pressure-side sliding cam surface 90S. The pressure-side auxiliary cam surface 90A is configured to contact the center-side auxiliary cam surface 60A. The pressure-side auxiliary cam surface 90A is configured to generate a force from the pressure plate 70 toward the clutch center 40 to increase the pressing force (contact force) between the input-side rotating plate 20 and the output-side rotating plate 22 during relative rotation with respect to the clutch center 40. The pressure-side sliding cam surface 90S is configured to contact the center-side sliding cam surface 60S. The pressure-side sliding cam surface 90S is configured to reduce the pressing force (contact force) between the input-side rotating plate 20 and the output-side rotating plate 22 during relative rotation with respect to the clutch center 40, thereby separating the pressure plate 70 from the clutch center 40. In adjacent pressure-side cam portions 90 in the rotational direction S, the pressure-side auxiliary cam surface 90A of one pressure-side cam portion 90L and the pressure-side sliding cam surface 90S of the other pressure-side cam portion 90M are arranged to face each other in the rotational direction S.

[0062] Here, the functions of the center 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 shown in FIG. Figure 8A As shown, a rotational force in the first rotational direction S1 is applied to the pressure plate 70. Consequently, the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A act to generate a force in the first direction D1 on the pressure plate 70. This causes the pressure plate 70 to move closer to the clutch center portion 40 (the first direction D1), increasing the contact force between the input-side rotating plate 20 and the output-side rotating plate 22.

[0063] On the other hand, when the rotation speed of the output shaft 15 exceeds the rotation speed of the input gear 35 and the clutch housing 30 and a reverse torque is generated, as shown in FIG. Figure 8B As shown, a rotational force in the first rotational direction S1 is applied to the clutch center portion 40. Consequently, the center-side sliding cam surface 60S and the pressure-side sliding cam surface 90S move the pressure plate 70 in the second direction D2, releasing the contact force between the input-side rotating plate 20 and the output-side rotating plate 22. This prevents adverse effects on the engine and transmission caused by reverse torque.

[0064] like Figure 4 as well as Figure 5 As shown, the pressure plate 70 has a pressure side cam hole 73H that passes through a portion of the main body 72. The pressure side cam hole 73H is located radially outward of the cylindrical portion 80. The pressure side cam hole 73H extends from the side of the cylindrical portion 80 to a position radially outward of the pressure side cam portion 90. The pressure side cam hole 73H is formed between the pressure side auxiliary cam surface 90A and the pressure side sliding cam surface 90S of the adjacent pressure side cam portion 90. Figure 5 as well as Figure 7 As shown, the pressure-side auxiliary cam surface 90A overlaps a portion of the pressure-side cam hole 73H when viewed from the axial direction of the pressure plate 70. When the clutch center 40 and the pressure plate 70 are assembled, the boss portion 54 of the clutch center 40 is located within the pressure-side cam hole 73H.

[0065] like Figure 4 As shown, the pressure plate 70 has a plurality of pressure side interlocking teeth 77 formed on the outer peripheral surface of the main body 72. The pressure side interlocking teeth 77 hold at least one output side rotating plate 22. The pressure side interlocking teeth 77 are located closer to the first direction S1 side than the flange 98. The pressure side interlocking teeth 77 are located radially outward than the cylindrical portion 80. The pressure side interlocking teeth 77 are located radially outward than the pressure side cam portion 90. The pressure side interlocking teeth 77 are located radially outward than the pressure side cam portion 90. The plurality of pressure side interlocking teeth 77 are arranged along the rotation direction S. The plurality of pressure side interlocking teeth 77 are arranged at equal intervals in the rotation direction S. In addition, in the present embodiment, since a portion of the pressure side interlocking teeth 77 is removed, the intervals between the portions are wider, but the other adjacent pressure side interlocking teeth 77 are arranged at equal intervals.

[0066] like Figure 6 and Figure 7 As shown, the spring receiving portion 84 is formed in the pressure side cam portion 90. The spring receiving portion 84 is formed to be recessed from the second direction D2 toward the first direction D1. The spring receiving portion 84 is formed into an elliptical shape when viewed from the direction D (see also Figure 9 The spring housing portion 84 houses the clutch spring 25 (see Figure 1 ). The spring receiving portion 84 is arranged in alignment with the pressure side auxiliary cam surface 90A in the rotation direction S. In addition, "arrangement" means that the spring receiving portion 84 does not need to be adjacent to the pressure side auxiliary cam surface 90A. The spring receiving portion 84 and the pressure side auxiliary cam surface 90A may be separated in the rotation direction S, or other elements (such as recesses, etc.) that are integrated with the pressure side cam portion 90 may be provided between the spring receiving portion 84 and the pressure side auxiliary cam surface 90A in the rotation direction S. The spring receiving portion 84 is arranged between the pressure side auxiliary cam surface 90A and the pressure side sliding cam surface 90S in the rotation direction S. As Figure 1As shown, a first retaining groove 115 is formed in the spring receiving portion 84, which is recessed from the second direction D2 toward the first direction D1. The first retaining groove 115 retains an end portion 25A of the clutch spring 25, described later, in the first direction D1. The first retaining groove 115 secures the end portion 25A in the first direction D1 to the pressure plate 70. The first retaining groove 115 is formed in a circular shape when viewed from the direction D. The inner diameter of the first retaining groove 115 is the same as or smaller than the outer diameter of the clutch spring 25. By fitting the end portion 25A in the first direction D1 of the clutch spring 25 into the first retaining groove 115, the first retaining groove 115 secures the end portion 25A in the first direction D1 to the pressure plate 70. Alternatively, as long as the first retaining groove 115 can prevent the end portion 25A in the first direction D1 from moving relative to the pressure plate 70 in the rotational direction S, the first retaining groove 115 does not need to be circular when viewed from the direction D (that is, a gap may be partially formed between the inner circumferential surface of the first retaining groove 115 and the outer circumferential surface of the clutch spring 25). The first holding groove 115 may be formed in an elliptical shape when viewed from the direction D, for example.

[0067] like Figure 1 and Figure 9 As shown, the clutch spring 25 is housed in the spring housing portion 84. The clutch spring 25 applies force to the pressure plate 70 toward the clutch center portion 40. That is, the clutch spring 25 applies force to the pressure plate 70 in the first direction D1. The clutch spring 25 is, for example, a coil spring obtained by winding spring steel into a spiral shape. The clutch spring 25 is, for example, formed into a cylindrical shape. The end 25A of the clutch spring 25 in the first direction D1 contacts the pressure plate 70. The end 25B of the clutch spring 25 in the second direction D2 contacts the stop plate 100. As shown in FIG. Figure 10A as well as Figure 10B As shown, the center side auxiliary cam surface 60A and the pressure side auxiliary cam surface 90A are separated from each other in the rotation direction S (see Figure 10A ) until they come into contact with each other (refer to Figure 10B ), the axis 25L of the clutch spring 25 is inclined in the direction from the pressure-side auxiliary cam surface 90A toward the clutch spring 25 (i.e., the second rotational direction S2) as it moves from the first direction D1 to the second direction D2 (refer to Figure 10B ), or parallel to a straight line extending in the direction D which is the direction in which the platen 70 moves (refer to Figure 10A According to this method, in the state where the clutch is disconnected (refer to Figure 10A ) to the clutch connected state (refer to Figure 10B ) when the clutch spring 25 is shifted, no restoring force is generated in the clutch spring 25 in the direction from the clutch spring 25 toward the pressure side auxiliary cam surface 90A (i.e., the first rotation direction S1). The axis 25L of the clutch spring 25 may also be Figure 10A Status to Figure 10B In the entire range of the state, as it moves from the first direction D1 to the second direction D2, it tilts in the direction from the pressure side auxiliary cam surface 90A toward the clutch spring 25 (ie, the second rotation direction S2). Figure 10A In the example shown, when the clutch is disengaged, the axis 25L of the clutch spring 25 is parallel to the straight line extending in the direction D, but can also be inclined in the direction from the pressure-side auxiliary cam surface 90A toward the clutch spring 25 (i.e., the second rotational direction S2) as it moves from the first direction D1 to the second direction D2.

[0068] like Figure 1 As shown, the stopper plate 100 is configured to contact the pressure plate 70. Alternatively, the stopper plate 100 may be configured to contact a component that is movable in conjunction with the pressure plate 70 in the direction D. The stopper plate 100 is a component that prevents the pressure plate 70 from separating from the clutch central portion 40 in the second direction D2 by more than a predetermined distance. The stopper plate 100 is fixed to the clutch central portion 40. The stopper plate 100 is secured to the boss portion 54 of the clutch central portion 40 by bolts 28. With the clutch spring 25 housed in the spring housing 84, the stopper plate 100 is secured to the boss portion 54 of the clutch central portion 40 by bolts 28. The stopper plate 100 is annular in plan view. A second retaining groove 120 is formed in the stopper plate 100, recessed from the first direction D1 toward the second direction D2. The second retaining groove 120 retains the end portion 25B of the clutch spring 25 in the second direction D2. The second retaining groove 120 secures the end portion 25B in the second direction D2 to the stopper plate 100. The second retaining groove 120 is formed in a circular shape when viewed from the direction D. The inner diameter of the second retaining groove 120 is the same as or smaller than the outer diameter of the clutch spring 25. By fitting the end portion 25B in the second direction D2 of the clutch spring 25 into the second retaining groove 120, the second retaining groove 120 secures the end portion 25B in the second direction D2 to the pressure plate 70. Furthermore, as long as the second retaining groove 120 can prevent the end portion 25B in the second direction D2 from moving relative to the pressure plate 70 in the rotational direction S, the second retaining groove 120 need not be formed in a circular shape when viewed from the direction D (that is, a gap may be partially formed between the inner circumferential surface of the second retaining groove 120 and the outer circumferential surface of the clutch spring 25). For example, the second retaining groove 120 may also be formed in an elliptical shape when viewed from the direction D.

[0069] like Figure 1 As shown, the lowering unit 110 of this embodiment includes a first retaining groove 115 and a second retaining groove 120. Figure 10A as well as Figure 10B As shown, the lowering unit 110 is in a state where it is separated from the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A in the rotation direction S (see FIG. Figure 10A) to the period of close contact (refer to Figure 10B ), reduces the restoring force of the clutch spring 25 in the direction from the clutch spring 25 toward the pressure side auxiliary cam surface 90A (i.e., the first rotational direction S1). In this embodiment, the reducing unit 110 is in a state of being separated from the center side auxiliary cam surface 60A and the pressure side auxiliary cam surface 90A in the rotational direction S (refer to Figure 10A ) until they come into contact with each other (refer to Figure 10B ), reducing the restoring force of the clutch spring 25 in the direction from the clutch spring 25 toward the pressure-side assist cam surface 90A (ie, the first rotational direction S1).

[0070] like Figure 10A as well as Figure 10B As shown, the lowering unit 110 is in a state where the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A are separated from each other in the rotation direction S (see FIG. Figure 10A ) until they come into contact with each other (refer to Figure 10B ), suppressing (for example, limiting) the relative movement of the end portion 25A of the clutch spring 25 in the first direction D1 relative to the pressure plate 70 in the rotation direction S, and the relative movement of the end portion 25B of the clutch spring 25 in the second direction D2 relative to the stopper plate 100 in the rotation direction S. In this embodiment, the lowering unit 110 is in a state where the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A are separated in the rotation direction S (see Figure 10A ) until they come into contact with each other (refer to Figure 10B ), suppressing (e.g., limiting) the relative movement of the end portion 25A of the clutch spring 25 in the first direction D1 relative to the pressure plate 70 in the rotational direction S, and the relative movement of the end portion 25B of the clutch spring 25 in the second direction D2 relative to the stop plate 100 in the rotational direction S. Furthermore, the lowering unit 110 may slightly permit relative movement of the end portion 25A in the first direction D1 relative to the pressure plate 70 in the rotational direction S, and relative movement of the end portion 25B in the second direction D2 relative to the stop plate 100 in the rotational direction S, within a limit capable of reducing the restoring force.

[0071] like Figure 10A as well as Figure 10BAs shown, the lowering unit 110 fixes the end 25A of the clutch spring 25 in the first direction D1 to the pressure plate 70, and fixes the end 25B of the clutch spring 25 in the second direction D2 to the stopper plate 100. In this embodiment, the lowering unit 110 fixes the end 25A of the clutch spring 25 in the first direction D1 to the pressure plate 70 via the first retaining groove 115, and fixes the end 25B of the clutch spring 25 in the second direction D2 to the stopper plate 100 via the second retaining groove 120.

[0072] Next, the operation of the clutch device 10 of this embodiment will be described. As described above, the clutch device 10 is disposed between the engine and the transmission of a motorcycle, and transmits and disconnects the engine's rotational drive force to the transmission when the driver operates the clutch (e.g., by operating a lever or pressing an operating button).

[0073] In the clutch device 10, when the driver of the motorcycle does not operate the clutch, the clutch release mechanism (not shown) does not press the push rod 16A. Therefore, the pressure plate 70 presses the input-side rotating plate 20 due to the biasing force (elastic force) of the clutch spring 25. As a result, the clutch center portion 40 is driven to rotate by the input-side rotating plate 20 and the output-side rotating plate 22 being frictionally coupled against each other (i.e., the clutch is engaged). This transmits the engine's rotational drive force to the clutch center portion 40, driving the output shaft 15 to rotate.

[0074] On the other hand, in the clutch device 10, when the driver of the motorcycle performs a clutch operation in the state where the clutch is connected, the clutch release mechanism (not shown) presses the push rod 16A, so that the pressure plate 70 overcomes the force of the clutch spring 25 and displaces in the direction of separation from the clutch central portion 40 (the second direction D2). As a result, the clutch central portion 40 is in a state where the friction connection between the input-side rotating plate 20 and the output-side rotating plate 22 is released (i.e., the clutch is disconnected), and the rotational drive of the output shaft 15 is attenuated or stopped. As a result, the rotational drive force of the engine is disconnected relative to the clutch central portion 40. In addition, in the state from which the clutch is connected (refer to Figure 10B ) is transferred to the cut-off state (refer to Figure 10A ), the reduction unit 110 reduces the restoring force of the clutch spring 25 in the direction from the clutch spring 25 toward the pressure-side auxiliary cam surface 90A (ie, the first rotational direction S1). Here, the clutch spring 25 does not generate the restoring force.

[0075] Furthermore, when the clutch is disconnected (see Figure 10A) When the driver releases the clutch operation (e.g., releases the operation of the operating lever or releases the pressing of the operating button), the clutch release mechanism (not shown) releases the pressing of the pressure plate 70 via the pressing member 16B, and the pressure plate 70 is displaced in the direction (first direction D1) approaching the clutch center portion 40 by the biasing force of the clutch spring 25. Figure 10A ) to the connected state (refer to Figure 10B ), the lowering unit 110 reduces the restoring force of the clutch spring 25 in the direction from the clutch spring 25 toward the pressure-side auxiliary cam surface 90A (i.e., the first rotational direction S1). During this period, the clutch spring 25 does not generate the aforementioned restoring force. Consequently, the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A are prevented from suddenly contacting due to the restoring force.

[0076] As described above, according to the clutch device 10 of this embodiment, the lowering unit 110 reduces the restoring force of the clutch spring 25 in the direction from the clutch spring 25 toward the pressure-side auxiliary cam surface 90A (i.e., the first rotational direction S1) during the period from the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A moving from a state of separation in the rotational direction S to approaching and contacting each other. By thus reducing the restoring force that could otherwise be generated by the clutch spring 25, the lowering unit 110 can prevent the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A from suddenly contacting each other due to the restoring force. In other words, the lowering unit 110 can prevent the clutch from suddenly engaging.

[0077] In the clutch device 10 of this embodiment, the lowering unit 110 suppresses relative movement of the end portion 25A of the clutch spring 25 in the first direction D1 relative to the pressure plate 70 in the rotational direction S, and relative movement of the end portion 25B of the clutch spring 25 in the second direction D2 relative to the stopper plate 100 in the rotational direction S, while the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A move from a state of separation in the rotational direction S to a state of proximity and contact with each other. During this period, as the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A move from a state of separation in the rotational direction S to a state of proximity and contact with each other, the axis 25L of the clutch spring 25 tilts in the direction from the pressure-side auxiliary cam surface 90A toward the clutch spring 25 (i.e., the second rotational direction S2), or becomes parallel to a straight line extending in the direction D, which is the direction of movement of the pressure plate 70, as the clutch spring 25 moves from the first direction D1 to the second direction D2. This configuration prevents the clutch spring 25 from generating a restoring force in the direction from the clutch spring 25 toward the pressure-side auxiliary cam surface 90A.

[0078] In the clutch device 10 of this embodiment, the lowering unit 110 secures the end 25A of the clutch spring 25 in the first direction D1 to the pressure plate 70, and secures the end 25B of the clutch spring 25 in the second direction D2 to the stopper plate 100. This configuration more reliably suppresses movement of the clutch spring 25 relative to the pressure plate 70 and the stopper plate 100. Consequently, no restoring force is generated in the clutch spring 25 in the direction from the clutch spring 25 toward the pressure-side assist cam surface 90A.

[0079] In the clutch device of this embodiment, the lowering unit 110 includes a first retaining groove 115 formed in the pressure plate 70, recessed from the second direction D2 toward the first direction D1, and retaining the end D1 of the clutch spring 25 in the first direction D1; and a second retaining groove 120 formed in the stopper plate 100, recessed from the first direction D1 toward the second direction D2, and retaining the end 25B of the clutch spring 25 in the second direction D2. This configuration makes it easier to secure the clutch spring 25 to the pressure plate 70 and the stopper plate 100.

[0080] <Second embodiment>

[0081] Figure 11A and Figure 11B This is a cross-sectional view showing a portion of a clutch device 210 according to the second embodiment. The clutch device 210 includes an output shaft 15, an input-side rotating plate 20, an output-side rotating plate 22, a clutch housing 30, a clutch center portion 40, a pressure plate 270, a stopper plate 300, a clutch spring 225, and a lowering unit 310.

[0082] like Figure 11A and Figure 12 As shown, the pressure plate 270 includes a spring receiving portion 284 for receiving the clutch spring 225. The spring receiving portion 284 is an example of a receiving portion. The spring receiving portion 284 is formed on the pressure-side cam portion 90. The spring receiving portion 284 is formed so as to be recessed from the second direction D2 toward the first direction D1. The spring receiving portion 284 is divided by a partition wall 284W. The spring receiving portion 284 is formed into a circular shape when viewed from the direction D (see also FIG. Figure 12). The spring housing portion 284 is formed so that the inner diameter increases from the first direction D1 toward the second direction D2. The spring housing portion 284 is arranged in an array with the pressure-side auxiliary cam surface 90A in the rotation direction S. In addition, "arranged" means that the spring housing portion 284 does not need to be adjacent to the pressure-side auxiliary cam surface 90A. The spring housing portion 284 and the pressure-side auxiliary cam surface 90A can be separated in the rotation direction S, or other elements (such as a recess, etc.) that are integral with the pressure-side cam portion 90 can be provided between the spring housing portion 284 and the pressure-side auxiliary cam surface 90A in the rotation direction S. The spring housing portion 284 is arranged between the pressure-side auxiliary cam surface 90A and the pressure-side sliding cam surface 90S in the rotation direction S.

[0083] like Figure 11A as well as Figure 12 As shown, the clutch spring 225 is housed in the spring housing 284. The clutch spring 225 contacts the inner circumferential surface 284P of the partition wall 284W, extending across the entirety of the partition wall 284W (i.e., extending across the entirety of the partition wall 284W in the direction D). The clutch spring 225 is, for example, a conical spring made by spirally winding spring steel. The clutch spring 225 is formed, for example, in the shape of a truncated cone, with the outer diameter increasing from the first direction D1 to the second direction D2. The clutch spring 225 urges the pressure plate 270 toward the clutch center 40. Specifically, the clutch spring 225 urges the pressure plate 270 in the first direction D1. The end 225A of the clutch spring 225 in the first direction D1 contacts the pressure plate 270. The end 225A in the first direction D1 is non-slidable relative to the pressure plate 270. The end 225B of the clutch spring 225 in the second direction D2 contacts the stopper plate 300. The end portion 225B in the second direction D2 is configured to be slidable relative to the stopper plate 300. Figure 11A as well as Figure 11B As shown, the center side auxiliary cam surface 60A and the pressure side auxiliary cam surface 90A are separated from each other in the rotation direction S (see Figure 11A ) to the period of close contact (refer to Figure 11B ), the axis 225L of the clutch spring 225 is parallel to the straight line extending in the direction D, which is the direction in which the pressure plate 270 moves. In other words, the clutch spring 225 is not tilted. According to this embodiment, no restoring force is generated in the clutch spring 225 in the direction from the clutch spring 225 toward the pressure-side auxiliary cam surface 90A (i.e., the first rotational direction S1). In addition, Figure 11A Indicates the clutch is disconnected. Figure 11B Indicates the clutch is connected.

[0084] like Figure 11A As shown, the stop plate 300 is not formed with the second retaining groove 120 (refer to Figure 10A) Other than this point, the structure is the same as that of the stop plate 100.

[0085] like Figure 11A As shown, the lowering unit 310 of this embodiment is a partition wall 284W that partitions the spring storage portion 284. Figure 11A as well as Figure 11B As shown, the lowering unit 310 is in a state where the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A are separated from each other in the rotation direction S (see FIG. Figure 11A ) to the period of close contact (refer to Figure 11B ), the restoring force of the clutch spring 225 in the direction from the clutch spring 225 toward the pressure-side auxiliary cam surface 90A (i.e., the first rotational direction S1) is reduced. In this embodiment, the reducing unit 310 is in a state where the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A are separated from each other in the rotational direction S (refer to Figure 11A ) to the period of close contact (refer to Figure 11B ), suppressing the clutch spring 225 accommodated in the spring accommodation portion 284 from tilting in the rotation direction S. In this embodiment, the center side auxiliary cam surface 60A and the pressure side auxiliary cam surface 90A are separated from each other in the rotation direction S (refer to Figure 11A ) to the period of close contact (refer to Figure 11B ), the clutch spring 225 contacts the inner circumferential surface 284P of the partition wall 284W over the entire partition wall 284W (i.e., over the entire partition wall 284W in the direction D). Therefore, the clutch spring 225 does not tilt, and no restoring force is generated in the clutch spring 225 in the direction from the clutch spring 225 toward the pressure-side assist cam surface 90A (i.e., the first rotational direction S1).

[0086] In the clutch device 210 of the present embodiment, the lowering unit 310 suppresses the clutch spring 225 housed in the spring housing 284 from tilting in the rotational direction S while the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A move from being separated in the rotational direction S to being brought closer together and in contact with each other. In this manner, the clutch spring 225 is suppressed from tilting in the rotational direction S by the lowering unit 310, so that no restoring force is generated in the clutch spring 225 in the direction from the clutch spring 225 toward the pressure-side auxiliary cam surface 90A.

[0087] In the clutch device 210 of this embodiment, the lowering means 310 is a partition wall 284W that partitions the spring accommodating portion 284, and the clutch spring 225 contacts the inner circumferential surface 284P of the partition wall 284 W over the entirety of the partition wall 284 W. According to this embodiment, the clutch spring 225 does not tilt in the rotational direction S, and therefore, no restoring force is generated in the clutch spring 225 in the direction from the clutch spring 225 toward the pressure-side assist cam surface 90A.

[0088] In the clutch device 210 of this embodiment, the spring housing portion 284 is formed so that its inner diameter increases from the first direction D1 toward the second direction D2, and the clutch spring 225 is formed in a truncated cone shape. Due to this configuration, the clutch spring 225 does not tilt in the rotational direction S, and therefore, no restoring force is generated in the clutch spring 225 in the direction from the clutch spring 225 toward the pressure-side assist cam surface 90A.

[0089] <Third embodiment>

[0090] Figure 13 FIG is a cross-sectional view of the clutch device 410 of the third embodiment. Figure 13 As shown, the clutch device 410 includes the output shaft 15, the input-side rotating plate 20, the output-side rotating plate 22, the clutch housing 30, the clutch center 440, the pressure plate 470, the lifting plate 500, the clutch spring 25, and the lowering unit 510. The clutch device 410 is a so-called external release type clutch device.

[0091] like Figure 13 As shown, the side wall 33 of the clutch housing 30 extends from the edge of the bottom wall 31 in the first direction D1.

[0092] like Figure 13 As shown, the pressure plate 470 has a plurality of (three in this embodiment) bosses 554. The bosses 554 are components that support the lifting plate 500. The plurality of bosses 554 are arranged at equal intervals in the rotation direction S. The bosses 554 are formed into a cylindrical shape. The bosses 554 extend toward the clutch center portion 440 (i.e., toward the first direction D1). The bosses 554 are provided on the pressure side cam portion 90. As shown in FIG. Figure 14A and Figure 14B As shown, the boss portion 554 is located between the pressure side auxiliary cam surface 90A and the pressure side sliding cam surface 90S in the rotation direction S. A threaded hole 554H is formed in the boss portion 554. The threaded hole 554H extends along the axial direction of the pressure plate 470. The bolt 28 (see FIG. 28 ) for fixing the lifting plate 500 to the pressure plate 470 is inserted into the threaded hole 554H. Figure 13 ).

[0093] like Figure 13As shown, the clutch center portion 440 includes a spring receiving portion 484. The spring receiving portion 484 is an example of a receiving portion. The spring receiving portion 484 is formed on the main body 42. The spring receiving portion 484 is formed on the central cam portion 60. The spring receiving portion 484 is formed to be recessed from the first direction D1 toward the second direction D2. The spring receiving portion 484 is formed into an elliptical shape when viewed from the direction D. The spring receiving portion 484 receives the clutch spring 25. Figure 14A and Figure 14B As shown, the spring receiving portion 484 is aligned with the center-side auxiliary cam surface 60A in the rotational direction S. It should be noted that "aligned" means that the spring receiving portion 484 and the center-side auxiliary cam surface 60A do not need to be adjacent. The spring receiving portion 484 and the center-side auxiliary cam surface 60A can be separated in the rotational direction S, or another feature (such as a recess) integral with the center-side cam portion 60 can be provided between the spring receiving portion 484 and the center-side auxiliary cam surface 60A in the rotational direction S. The spring receiving portion 484 is positioned between the center-side auxiliary cam surface 60A and the center-side sliding cam surface 60S in the rotational direction S. A first retaining groove 515 is formed in the spring receiving portion 484, which is recessed from the first direction D1 toward the second direction D2. The first retaining groove 515 retains the end portion 25B of the clutch spring 25 in the second direction D2. The first retaining groove 515 secures the end portion 25B in the second direction D2 to the clutch center portion 440. The first retaining groove 515 has the same structure as the first retaining groove 115.

[0094] like Figure 13 As shown, the clutch spring 25 is housed in the spring housing portion 484. The end portion 25B of the clutch spring 25 in the second direction D2 contacts the clutch center portion 440. The end portion 25A of the clutch spring 25 in the first direction D1 contacts the lifting plate 500. Figure 14A as well as Figure 14B As shown, the center side auxiliary cam surface 60A and the pressure side auxiliary cam surface 90A are separated from each other in the rotation direction S (see Figure 14A ) until they come into contact with each other (refer to Figure 14B ), the axis 25L of the clutch spring 25 is inclined in the direction from the center auxiliary cam surface 60A toward the clutch spring 25 (i.e., the first rotation direction S1) as it moves from the second direction D2 to the first direction D1 (refer to Figure 14B ), or parallel to a straight line extending in the direction D which is the direction in which the pressing plate 470 moves (refer to Figure 14A According to this method, in the state where the clutch is disconnected (refer to Figure 14A ) to the clutch connected state (refer to Figure 14B) when the clutch spring 25 is shifted, no restoring force is generated in the clutch spring 25 in the direction from the clutch spring 25 toward the center auxiliary cam surface 60A (i.e., the second rotation direction S2). The axis 25L of the clutch spring 25 may also be Figure 14A Status to Figure 14B In the entire state of , the center auxiliary cam surface 60A is inclined in the direction toward the clutch spring 25 (ie, the first rotational direction S1 ) as it advances from the second direction D2 to the first direction D1 .

[0095] like Figure 13 As shown, the lift plate 500 is configured to contact the clutch center 40. Alternatively, the lift plate 500 may contact a component that rotates in conjunction with the clutch center 400. The lift plate 500 is a component used to displace the pressure plate 470 in direction D. The lift plate 500 prevents the pressure plate 470 from separating from the clutch center 40 in the second direction D2 by more than a predetermined distance. The lift plate 500 is fixed to the pressure plate 470. The lift plate 500 is secured to the boss 554 of the pressure plate 470 by bolts 28. The lift plate 500 rotates integrally with the pressure plate 470. The lift plate 500 moves in direction D relative to the clutch center 440 and rotates relative to the clutch center 440. The lift plate 500 is disc-shaped. A release bearing 503 is provided on the lift plate 500. The release bearing 503 is pressed by the release fork 512 of the clutch release mechanism (not shown). Here, the clutch release mechanism refers to a mechanical device that, in a vehicle such as a motorcycle equipped with the clutch device 410, presses the release bearing 503 toward the output shaft 15 (i.e., in the second direction D2) via the release fork 512 when the driver operates the clutch operating lever (not shown). The lift plate 500 supports the clutch spring 25 housed in the spring housing 484 of the clutch center portion 440. The lift plate 500 includes an insertion hole 504H for receiving the bolt 28 that secures the lift plate 500 to the pressure plate 470. A second retaining groove 520 is formed in the lift plate 500, which is recessed from the second direction D2 toward the first direction D1. The second retaining groove 520 retains the end 25A of the clutch spring 25 in the first direction D1. The second retaining groove 520 secures the end 25A in the first direction D1 to the lift plate 500. The second retaining groove 520 has the same structure as the second retaining groove 120.

[0096] like Figure 13 As shown, the lowering unit 510 of this embodiment includes a first retaining groove 515 and a second retaining groove 520. Figure 14A as well as Figure 14B As shown, the lowering unit 510 is in a state where the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A are separated from each other in the rotation direction S (see FIG. Figure 14A ) to the period of close contact (refer to Figure 14B ), reducing the restoring force in the clutch spring 25 in the direction from the clutch spring 25 toward the center-side auxiliary cam surface 60A (i.e., the second rotational direction S2). In this embodiment, the lowering unit 510 is in a state where the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A are separated from each other in the rotational direction S (refer to Figure 14A ) to the period of close contact (refer to Figure 14B ), reducing the restoring force of the clutch spring 25 in the direction from the clutch spring 25 toward the center-side auxiliary cam surface 60A (ie, the second rotational direction S2).

[0097] like Figure 14A as well as Figure 14B As shown, the lowering unit 510 is in a state where the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A are separated from each other in the rotation direction S (see FIG. Figure 14A ) until they come into contact with each other (refer to Figure 14B ), which prevents the end portion 25B of the clutch spring 25 in the second direction D2 from moving relative to the clutch central portion 440 in the rotational direction S, and the end portion 25A of the clutch spring 25 in the first direction D1 from moving relative to the lifting plate 500 in the rotational direction S. In this embodiment, the lowering unit 510 is in a state where the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A are separated in the rotational direction S (see FIG. Figure 14A ) until they come into contact with each other (refer to Figure 14B ), suppressing relative movement of the end portion 25B of the clutch spring 25 in the second direction D2 with respect to the clutch central portion 440 in the rotational direction S, and suppressing relative movement of the end portion 25A of the clutch spring 25 in the first direction D1 with respect to the lifting plate 500 in the rotational direction S. Furthermore, the lowering unit 510 may slightly permit relative movement of the end portion 25B in the second direction D2 with respect to the clutch central portion 440 in the rotational direction S, and relative movement of the end portion 25A in the first direction D1 with respect to the lifting plate 500 in the rotational direction S, within a limit capable of reducing the restoring force.

[0098] like Figure 14A as well as Figure 14BAs shown, the lowering unit 510 secures the end 25B of the clutch spring 25 in the second direction D2 to the clutch central portion 440, and secures the end 25A of the clutch spring 25 in the first direction D1 to the lifting plate 500. In this embodiment, the lowering unit 510 secures the end 25B of the clutch spring 25 in the second direction D2 to the clutch central portion 440 via the first retaining groove 515, and secures the end 25A of the clutch spring 25 in the first direction D1 to the lifting plate 500 via the second retaining groove 520.

[0099] As described above, according to the clutch device 410 of this embodiment, the reducing unit 510 reduces the restoring force of the clutch spring 25 in the direction from the clutch spring 25 toward the center-side auxiliary cam surface 60A (i.e., the second rotational direction S2) during the period from the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A moving from a state of separation in the rotational direction S to approaching and contacting each other. By thus reducing the restoring force that could otherwise be generated by the clutch spring 25, the reducing unit 510 can prevent the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A from suddenly contacting each other due to the restoring force. In other words, the reducing unit 510 can prevent the clutch from suddenly engaging.

[0100] In the clutch device 410 of this embodiment, the lowering unit 510 suppresses relative movement of the end portion 25B of the clutch spring 25 in the second direction D2 with respect to the clutch central portion 440 in the rotational direction S, and of the end portion 25A of the clutch spring 25 in the first direction D1 with respect to the lift plate 500 in the rotational direction S, during the period from when the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A move from a state of separation in the rotational direction S to when they approach and contact each other. During the period from when the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A move from a state of separation in the rotational direction S to when they approach and contact each other, the axis 25L of the clutch spring 25 tilts in the direction from the center-side auxiliary cam surface 60A toward the clutch spring 25 (i.e., the first rotational direction S1), or becomes parallel to a straight line extending in the direction D, which is the direction of movement of the pressure plate 70, as the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A move from the second direction D2 toward the first direction D1. In this manner, no restoring force is generated in the clutch spring 25 in the direction from the clutch spring 25 toward the center-side auxiliary cam surface 60A.

[0101] <Fourth embodiment>

[0102] Figure 15A and Figure 15B1 is a cross-sectional view showing a portion of a clutch device 610 according to a fourth embodiment. The clutch device 610 includes an output shaft 15, an input-side rotating plate 20, an output-side rotating plate 22, a clutch housing 30, a clutch center portion 540, a pressure plate 470, a lifting plate 600, a clutch spring 225, and a lowering unit 710.

[0103] like Figure 15A and Figure 15B As shown, the clutch center portion 540 includes a spring receiving portion 584 for receiving the clutch spring 225. The spring receiving portion 584 is an example of a receiving portion. The spring receiving portion 584 is formed in the center cam portion 60. The spring receiving portion 584 is recessed from the first direction D1 toward the second direction D2. The spring receiving portion 584 is divided by a partition wall 584W. The spring receiving portion 584 is formed in a circular shape when viewed from the direction D. The inner diameter of the spring receiving portion 584 increases from the second direction D2 toward the first direction D1. The spring receiving portion 584 is arranged in alignment with the center auxiliary cam surface 60A in the rotational direction S. It should be noted that "arranged" means that the spring receiving portion 584 and the central auxiliary cam surface 60A do not need to be adjacent to each other. The spring receiving portion 584 and the central auxiliary cam surface 60A may be separated in the rotational direction S, or another element (such as a recessed portion) integral with the central cam portion 60 may be provided between the spring receiving portion 584 and the central auxiliary cam surface 60A in the rotational direction S. The spring receiving portion 584 is disposed between the central auxiliary cam surface 60A and the central sliding cam surface 60S in the rotational direction S.

[0104] like Figure 15A as well as Figure 15B As shown, the clutch spring 225 is housed in the spring housing portion 584. The clutch spring 225 is in contact with the inner circumferential surface 584P of the partition wall 584W over the entire partition wall 584W (i.e., over the entire partition wall 584W in the direction D). The clutch spring 225 urges the pressure plate 470 toward the clutch center portion 540. That is, the clutch spring 225 urges the pressure plate 470 in the first direction D1. The end 225B of the clutch spring 225 in the second direction D2 is in contact with the clutch center portion 540. The end 225B in the second direction D2 is configured to be non-slidable relative to the clutch center portion 540. The end 225A of the clutch spring 225 in the first direction D1 is in contact with the lifting plate 600. The end 225A in the first direction D1 is configured to be slidable relative to the lifting plate 600. In the state where the center side auxiliary cam surface 60A and the pressure side auxiliary cam surface 90A are separated in the rotation direction S (refer to Figure 15A ) to the period of close contact (refer to Figure 15B), the axis 225L of the clutch spring 225 is parallel to the straight line extending in the direction D, which is the direction in which the pressure plate 270 moves. In other words, the clutch spring 225 is not tilted. According to this embodiment, no restoring force is generated in the clutch spring 225 in the direction from the clutch spring 225 toward the center-side auxiliary cam surface 60A (i.e., the second rotational direction S2). In addition, Figure 15A Indicates the clutch is disconnected. Figure 15B Indicates the clutch is connected.

[0105] like Figure 15A As shown, the lifting plate 600 is not formed with the second holding groove 520 (refer to Figure 14A ) Other than this, the structure is the same as that of the lifting plate 500.

[0106] like Figure 15A As shown, the lowering unit 710 of this embodiment is a partition wall 584W that partitions the spring storage portion 584. Figure 15A as well as Figure 15B As shown, the lowering unit 710 is in a state where it is separated from the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A in the rotation direction S (see FIG. Figure 15A ) to the period of close contact (refer to Figure 15B ), the restoring force of the clutch spring 225 in the direction from the clutch spring 225 toward the center-side auxiliary cam surface 60A (i.e., the second rotational direction S2) is reduced. In this embodiment, the lowering unit 710 is in a state where the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A are separated from each other in the rotational direction S (refer to Figure 15A ) to the period of close contact with each other (refer to Figure 15B ), suppressing the clutch spring 225 accommodated in the spring accommodation portion 584 from tilting in the rotation direction S. In this embodiment, the center side auxiliary cam surface 60A and the pressure side auxiliary cam surface 90A are separated from each other in the rotation direction S (refer to Figure 15A ) to the period of close contact (refer to Figure 15B ), the clutch spring 225 contacts the inner circumferential surface 584P of the partition wall 584W over the entire partition wall 584W (i.e., over the entire partition wall 584W in the direction D). Therefore, the clutch spring 225 does not tilt, and no restoring force is generated in the clutch spring 225 in the direction from the clutch spring 225 toward the center-side auxiliary cam surface 60A (i.e., the second rotational direction S2).

[0107] In the clutch device 610 of this embodiment, the lowering unit 710 suppresses the clutch spring 225 housed in the spring housing 584 from tilting in the rotational direction S while the center-side auxiliary cam surface 60A and the pressure-side auxiliary cam surface 90A move from being separated in the rotational direction S to being brought closer together and in contact with each other. In this embodiment, the clutch spring 225 is suppressed from tilting in the rotational direction S by the lowering unit 710, so that no restoring force is generated in the clutch spring 225 in the direction from the clutch spring 225 toward the center-side auxiliary cam surface 60A.

[0108] In the clutch device 610 of this embodiment, the lowering means 710 is a partition wall 584W that partitions the spring accommodating portion 584, and the clutch spring 225 contacts the inner circumferential surface 584P of the partition wall 584 W over the entire portion of the partition wall 584 W. According to this embodiment, since the clutch spring 225 does not tilt in the rotational direction S, no restoring force is generated in the clutch spring 225 in the direction from the clutch spring 225 toward the center-side auxiliary cam surface 60A.

[0109] While preferred embodiments of the present invention have been described above, these embodiments are merely examples, and the present invention can be implemented in various other forms.

[0110] In the first embodiment, the end 25A of the clutch spring 25 in the first direction D1 is secured to the pressure plate 70 via the first retaining groove 115. However, the securing method is not limited to this. For example, the end 25A in the first direction D1 can be secured by adhering it to the pressure plate 70, or by placing a high-friction component at the contact portion between the pressure plate 70 and the end 25A in the first direction D1 to secure them to each other. Alternatively, the end 25A in the first direction D1 can be secured to the pressure plate 70 using a protrusion or the like. The end 25B in the second direction D2 of the clutch spring 25 can also be secured using a similar method. Furthermore, in the third embodiment, the method for securing the end 25B in the second direction D2 of the clutch spring 25 to the clutch center portion 440 and the method for securing the end 25A in the first direction D1 of the clutch spring 25 to the lifting plate 500 can also be the same.

[0111] In the second embodiment, the clutch spring 225 is in contact with the inner circumferential surface 284P of the partition wall 284W over the entirety of the partition wall 284W, thereby suppressing the clutch spring 225 from tilting. However, the present invention is not limited to this. For example, a protrusion protruding from the inner circumferential surface 284P of the partition wall 284W toward the clutch spring 225 may be used to suppress the clutch spring 225 from tilting. In the fourth embodiment, for example, a protrusion protruding from the inner circumferential surface 584P of the partition wall 584W toward the clutch spring 225 may be used to suppress the clutch spring 225 from tilting.

[0112] In the second embodiment, the clutch spring 225 contacts the inner circumferential surface 284P of the partition wall 284W over the entire partition wall 284W, thereby suppressing the clutch spring 225 from tilting. However, as long as the restoring force can be reduced, a small gap may be provided between the outer circumferential surface of the clutch spring 225 and the inner circumferential surface of the partition wall 284W over the entire partition wall 284W or partially. The same applies to the fourth embodiment.

[0113] In the first to fourth embodiments, the clutch central portions 40, 440, and 540 hold the output-side rotating plates 22. However, the clutch central portions 40, 440, and 540 do not necessarily hold the output-side rotating plates 22. In other words, all of the output-side rotating plates 22 may be held by the pressure plates 70, 270, and 470, and none of the clutch central portions 40, 440, and 540 may hold any output-side rotating plates 22.

[0114] [Explanation of Reference Numerals]

[0115] 10 Clutch device

[0116] 15 output shaft

[0117] 20 Input side rotating plate

[0118] 22 Output side rotating plate

[0119] 25 clutch spring

[0120] 25A End portion in the first direction

[0121] 25B end portion in the second direction

[0122] 25L axis

[0123] 40 clutch center

[0124] 54 boss part

[0125] 60 center side cam

[0126] 60A center side auxiliary cam surface

[0127] 60S center side sliding cam surface

[0128] 70 pressure plate

[0129] 84 spring storage part (storage part)

[0130] 90 pressure side cam

[0131] 90A pressure side auxiliary cam surface

[0132] 90S pressure side sliding cam surface

[0133] 100 stop plate

[0134] 110 lowering unit

[0135] 115 first holding groove

[0136] 120 second holding groove.

Claims

1. A clutch device that transmits or cuts off the rotational driving force of an input shaft relative to an output shaft, wherein: have: A clutch central portion is housed in a clutch housing that holds a plurality of input-side rotating plates that are driven to rotate by the rotation of the input shaft, and is driven to rotate together with the output shaft; a pressure plate, arranged to be able to approach or separate from the clutch center portion and to be relatively rotatable, and to hold a plurality of output-side rotating plates alternately arranged with the input-side rotating plates and to press the input-side rotating plates and the output-side rotating plates; a clutch spring configured to bias the pressure plate toward the first direction when the pressure plate approaches the clutch center and when the pressure plate moves away from the clutch center; as well as a stopper plate fixed to the clutch center portion and preventing the pressure plate from separating from the clutch center portion in the second direction by more than a predetermined distance; The end portion of the clutch spring in the first direction contacts the pressure plate, and the end portion of the clutch spring in the second direction contacts the stopper plate. The clutch central portion has a central auxiliary cam surface, which generates a force in a direction from the pressure plate toward the clutch central portion in order to increase the pressing force between the input-side rotating plate and the output-side rotating plate when the clutch central portion rotates relative to the pressure plate. The pressing plate has: a pressure-side auxiliary cam surface configured to contact the center-side auxiliary cam surface when the pressure plate rotates relative to the clutch center portion, and to generate a force in a direction from the pressure plate toward the clutch center portion in order to increase the pressing force between the input-side rotating plate and the output-side rotating plate; as well as The receiving portion is arranged in parallel with the pressure-side auxiliary cam surface in the rotation direction of the pressure plate and receives the clutch spring. The clutch device includes a reducing unit that reduces the restoring force of the clutch spring in a direction from the clutch spring toward the pressure-side auxiliary cam surface during a period in which the center-side auxiliary cam surface and the pressure-side auxiliary cam surface move from a state of separation in the rotational direction to a state in which they approach and contact each other.

2. The clutch device according to claim 1, wherein: The clutch center portion holds the output-side rotation plate.

3. The clutch device according to claim 1 or 2, wherein: The lowering unit suppresses the clutch spring accommodated in the accommodation portion from tilting in the rotational direction during a period from when the center-side auxiliary cam surface and the pressure-side auxiliary cam surface move from a state of being separated in the rotational direction to when they approach and contact each other.

4. The clutch device according to claim 3, wherein: The lowering unit is a partition wall that divides the storage portion. The clutch spring extends over the entire partition wall and contacts the inner peripheral surface of the partition wall.

5. The clutch device according to claim 4, wherein: The receiving portion is formed so that its inner diameter increases from the first direction toward the second direction. The clutch spring is formed in a truncated cone shape.

6. The clutch device according to claim 1 or 2, wherein: The lowering unit suppresses relative movement of the end portion of the clutch spring in the first direction relative to the pressure plate in the rotational direction and the end portion of the clutch spring in the second direction relative to the stop plate in the rotational direction during a period from when the center-side auxiliary cam surface and the pressure-side auxiliary cam surface are separated in the rotational direction to when they approach and contact each other. During the period from the state in which the central side auxiliary cam surface and the pressure side auxiliary cam surface are separated in the rotation direction to the state in which they approach and contact each other, the axis of the clutch spring is inclined in the direction from the pressure side auxiliary cam surface toward the clutch spring as it moves from the first direction toward the second direction, or is parallel to a straight line extending in the direction in which the pressure plate moves, i.e., the direction of movement.

7. The clutch device according to claim 6, wherein: The lowering unit fixes the end portion of the clutch spring in the first direction to the pressure plate, and fixes the end portion of the clutch spring in the second direction to the stopper plate.

8. The clutch device according to claim 7, wherein: The lowering unit comprises: a first holding groove formed in the pressure plate and recessed from the second direction toward the first direction, and holding an end portion of the clutch spring in the first direction; and A second holding groove is formed in the stopper plate and is recessed from the first direction toward the second direction, and holds an end portion of the clutch spring in the second direction.

9. A clutch device that transmits or cuts off the rotational driving force of an input shaft relative to an output shaft, wherein: have: A clutch central portion is housed in a clutch housing that holds a plurality of input-side rotating plates that are driven to rotate by the rotation of the input shaft, and is driven to rotate together with the output shaft; a pressure plate, arranged to be able to approach or separate from the clutch center portion and to be relatively rotatable, and to hold a plurality of output-side rotating plates alternately arranged with the input-side rotating plates and to press the input-side rotating plates and the output-side rotating plates; a clutch spring configured to bias the pressure plate toward the first direction when the pressure plate approaches the clutch center and when the pressure plate moves away from the clutch center; as well as A lifting plate is fixed to the pressure plate and prevents the pressure plate from being separated from the clutch center portion in the second direction by more than a predetermined distance. The end portion of the clutch spring in the first direction contacts the lifting plate, and the end portion of the clutch spring in the second direction contacts the clutch center portion. The clutch center portion has: a central auxiliary cam surface for generating a force in a direction from the pressure plate toward the clutch central portion in order to increase the pressing force between the input-side rotating plate and the output-side rotating plate when the clutch central portion rotates relative to the pressure plate; as well as The receiving portion is arranged in parallel with the central auxiliary cam surface in the rotation direction of the central portion of the clutch and receives the clutch spring. The pressure plate has a pressure-side auxiliary cam surface, which is configured to contact the center-side auxiliary cam surface when the pressure plate rotates relative to the clutch center portion, and to generate a force from the pressure plate toward the clutch center portion in order to increase the pressing force between the input-side rotating plate and the output-side rotating plate. The clutch device includes a reducing unit that reduces a restoring force in the clutch spring in a direction from the clutch spring toward the center-side auxiliary cam surface during a period in which the center-side auxiliary cam surface and the pressure-side auxiliary cam surface move from a state of separation in the rotational direction to a state in which they approach and contact each other.

10. The clutch device according to claim 9, wherein: The clutch center portion holds the output-side rotation plate.

11. The clutch device according to claim 9 or 10, wherein: The lowering unit suppresses the clutch spring accommodated in the accommodation portion from tilting in the rotational direction during a period from when the center-side auxiliary cam surface and the pressure-side auxiliary cam surface move from a state of being separated in the rotational direction to when they approach and contact each other.

12. The clutch device according to claim 11, wherein: The lowering unit is a partition wall that divides the storage portion. The clutch spring extends over the entire partition wall and contacts the inner peripheral surface of the partition wall.

13. The clutch device according to claim 9 or 10, wherein: The lowering unit suppresses relative movement of the end portion of the clutch spring in the first direction relative to the lifting plate in the rotational direction and the end portion of the clutch spring in the second direction relative to the clutch central portion in the rotational direction during a period from when the center-side auxiliary cam surface and the pressure-side auxiliary cam surface move from a state of separation in the rotational direction to when they approach and contact each other. During the period from the state in which the central side auxiliary cam surface and the pressure side auxiliary cam surface are separated in the rotation direction to the state in which they approach and contact each other, the axis of the clutch spring is inclined in the direction from the central side auxiliary cam surface toward the clutch spring as it moves from the second direction toward the first direction, or is parallel to a straight line extending in the direction in which the pressure plate moves, i.e., the direction of movement.

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