Clutch device

Abstract

To bring the drive-side clutch plate and the driven-side clutch plate into sufficient pressure contact. [Solution] The clutch device 10 comprises a clutch center 40, a pressure plate 70, a centrifugal clutch mechanism 120 having a plurality of weight members 122, and a clutch spring 25 that presses the pressure plate 70 as the centrifugal clutch mechanism 120 is operated, and the clutch spring 25 is configured to press the pressure plate 70 in a first direction D1 by the weight member 122 moving from a radially inner position PI1 to a radially outer position PO1, thereby pressurizing the drive side clutch plate 20 and the driven side clutch plate 22 together, and the end 25D1 in the first direction D1 of the clutch spring 25 is located on the second direction D2 surface side of the pressure plate 70 and on the second direction D2 side of the end 77D1 in the first direction D1 of the engaging tooth 77 of the pressure plate 70.

Description

[Technical Field]

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

[0002] Straddle-type vehicles such as motorcycles are equipped with a clutch device that can transmit and interrupt the rotational driving force of a driving source such as an engine to a driving wheel. For example, Patent Document 1 discloses a clutch device that has an input member connected to the engine, an output member connected to the driving wheel, a clutch member (hereinafter referred to as a clutch center) connected to the output member, and a pressure member (hereinafter referred to as a pressure plate) that can move toward or away from the clutch center. Patent Document 1 also discloses a centrifugal clutch means in which a weight member moves from a first position to a second position due to centrifugal force generated by rotation of a clutch housing, thereby pressing a driving-side clutch plate and a driven-side clutch plate into contact with each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-030211 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the clutch center holds some of the driven clutch plates, and the pressure plate holds some of the other driven clutch plates. However, if the pressure plate holds all of the driven clutch plates, there is a risk that the driving clutch plates and the driven clutch plates may not be sufficiently pressed together even when the weight member moves from the first position to the second position.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to provide a clutch device that can bring the driving side clutch plates and the driven side clutch plates into sufficient pressure contact with each other. [Means for solving the problem]

[0006] The clutch device of the present invention is a clutch device that transmits or cuts off the rotational drive force of an input member to an output member, and includes: a clutch center that is housed in a clutch housing that holds a plurality of drive-side clutch plates that are rotationally driven by the rotational drive of the input member and that is rotationally driven together with the output member; a pressure plate that is provided to be able to approach or move away from the clutch center and to be rotatable relative to the clutch center, that holds all of a plurality of driven-side clutch plates that are arranged alternately with the drive-side clutch plates and that is capable of pressing the drive-side clutch plates and the driven-side clutch plates; a centrifugal clutch mechanism having a plurality of weight members that are movable, as the centrifugal force associated with the rotation of the clutch housing increases, from a first position at which the pressure contact force between the drive-side clutch plates and the driven-side clutch plates is released and the rotational drive force of the input member is cut off from being transmitted to the output member, to a second position at which the drive-side clutch plates and the driven-side clutch plates are pressed together and the rotational drive force of the input member is transmitted to the output member; a pressing member that presses the pressure plate upon actuation, wherein when a direction in which the pressure plate approaches the clutch center is defined as a first direction and a direction in which the pressure plate moves away from the clutch center is defined as a second direction, the pressure plate comprises a base wall, an outer circumferential wall that extends from the base wall in the first direction and is formed in an annular shape when viewed from the axial direction of the output member, and is formed to hold all of the driven-side clutch plates and protrude radially outward from the outer circumferential surface of the outer circumferential wall. the pressing member is configured to press the pressure plate in the first direction by the weight member moving from the first position to the second position, thereby bringing the driving-side clutch plate and the driven-side clutch plate into pressure contact, and an end of the pressing member in the first direction is located on the second-direction surface side of the pressure plate and on the second-direction side of the end of the engaging teeth in the first direction.

[0007] In the clutch device according to the present invention, the end of the pressing member in the first direction, which presses the pressure plate in response to operation of the centrifugal clutch mechanism, is located on the second-direction surface of the pressure plate and further toward the second direction than the end of the engaging teeth in the first direction. According to the above aspect, the pressing force from the pressure plate pressed by the pressing member is efficiently transmitted to the driving-side clutch plate and the driven-side clutch plate. This allows the driving-side clutch plate and the driven-side clutch plate to be sufficiently pressed into contact with each other.

[0008] Another clutch device according to the present invention is a clutch device that transmits or cuts off the rotational drive force of an input member to an output member, the clutch device comprising: a clutch center that is housed in a clutch housing that holds a plurality of drive-side clutch plates that are rotationally driven by the rotational drive of the input member and that is rotationally driven together with the output member; a pressure plate that is provided so as to be able to approach or move away from the clutch center and to be rotatable relative to the clutch center, that holds all of a plurality of driven-side clutch plates that are arranged alternately with the drive-side clutch plates, and that is capable of pressing the drive-side clutch plates and the driven-side clutch plates; and a pressure plate that, as the centrifugal force increases with rotation of the clutch housing, releases the pressure contact force between the drive-side clutch plates and the driven-side clutch plates from a first position that can cut off the transmission of the rotational drive force of the input member to the output member, thereby pressing the drive-side clutch plates and the driven-side clutch plates together, thereby enabling the rotational drive force of the input member to be transmitted to the output member. and a pressure member that is positioned between the drive-side clutch plate and the driven-side clutch plate and the clutch housing in the axial direction of the output member, and that moves in the axial direction as the weight members move from the first position to the second position, thereby pressing the drive-side clutch plate and the driven-side clutch plate together, wherein the pressure plate extends in the axial direction of the output member and comprises an outer circumferential wall that is formed in an annular shape when viewed in the axial direction of the output member, a plurality of engaging teeth that are arranged in the circumferential direction and that are formed to protrude radially outward from the outer circumferential surface of the outer circumferential wall, and a plurality of spline grooves that are formed between adjacent engaging teeth, and the pressure member is positioned radially outward of the engaging teeth and has a pressing surface that can press the drive-side clutch plate or the driven-side clutch plate.

[0009] In another clutch device according to the present invention, the pressing member is located radially outward of the mating teeth and has a pressing surface that can press against the drive-side clutch plate or the driven-side clutch plate. According to this aspect, the pressing force from the pressing surface of the pressing member, which moves axially as the weight member moves, is efficiently transmitted to the drive-side clutch plate and the driven-side clutch plate. This allows the drive-side clutch plate and the driven-side clutch plate to be sufficiently pressed against each other. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a clutch device that can bring the drive-side clutch plates and the driven-side clutch plates into sufficient pressure contact. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing a part of a clutch device according to a first embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the clutch center and pressure plate according to the first embodiment. [Figure 3] FIG. 3 is a perspective view of the pressure plate according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a part of the clutch device according to the first embodiment. [Figure 5A] FIG. 5A is a schematic diagram illustrating the action of the center-side assist cam surface and the pressure-side assist cam surface. [Figure 5B] FIG. 5B is a schematic diagram illustrating the action of the center-side slipper cam surface and the pressure-side slipper cam surface. [Figure 6] FIG. 6 is a cross-sectional view showing a part of a clutch device according to a first modified example. [Figure 7] FIG. 7 is a cross-sectional view showing a part of a clutch device according to a second modified example. [Figure 8] FIG. 8 is a cross-sectional view showing a part of a clutch device according to the second embodiment. [Figure 9]FIG. 9 is a perspective view of a centrifugal clutch mechanism according to the second embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing a part of a clutch device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

[0013] First Embodiment FIG. 1 is a cross-sectional view showing a portion of a clutch device 10 according to a first embodiment. The clutch device 10 is provided on a vehicle such as a motorcycle. The clutch device 10 is a device that transmits or cuts off the rotational driving force of an input member (crankshaft) of a driving source (e.g., an engine) of the motorcycle to an output shaft 15. The clutch device 10 is a device that transmits or cuts off the rotational driving force of the input member to a driving wheel (rear wheel) via the output shaft 15. The clutch device 10 is disposed between the driving source and a transmission. The output shaft 15 is an example of an output member.

[0014] In the following description, the direction in which the pressure plate 70 of the clutch device 10 approaches and moves away from the clutch center 40 is referred to as direction D, the direction in which the pressure plate 70 approaches the clutch center 40 is referred to as a first direction D1, and the direction in which the pressure plate 70 moves away from the clutch center 40 is referred to as a second direction D2. The circumferential direction of the clutch center 40 and the pressure plate 70 is referred to as a circumferential direction S, and the direction from one pressure-side cam portion 90 to the other pressure-side cam portion 90 with respect to the circumferential direction S (the direction from one center-side cam portion 60 to the other center-side cam portion 60) is referred to as a first circumferential direction S1 (see FIG. 3), and the direction from the other pressure-side cam portion 90 to one pressure-side cam portion 90 (the direction from the other center-side cam portion 60 to one center-side cam portion 60) is referred to as a second circumferential direction S2 (see FIG. 3). In this embodiment, the axial direction of the output shaft 15, the axial direction of the clutch housing 30, the axial direction of the clutch center 40, and the axial direction of the pressure plate 70 are the same as direction D. Furthermore, the pressure plate 70 and the clutch center 40 rotate in a first circumferential direction S1 (i.e., the direction from the center-side assist cam surface 60A of one center-side cam portion 60 toward the center-side slipper cam surface 60S). However, the above directions are merely defined for the convenience of explanation, and do not limit in any way the installation mode of the clutch device 10 or the present invention.

[0015] As shown in FIG. 1, the clutch device 10 includes an output shaft 15, a driving side clutch plate 20, a driven side clutch plate 22, a clutch housing 30, a clutch center 40, a pressure plate 70, and a centrifugal clutch mechanism 120.

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

[0017] As shown in FIG. 1 , the output shaft 15 includes a hollow portion 15H, in which a push rod 16A and a push member 16B are provided adjacent to the push rod 16A. The hollow portion 15H functions as a passage for clutch oil. The clutch oil flows through the output shaft 15, i.e., the hollow portion 15H. The push rod 16A and the push member 16B are slidably provided within the hollow portion 15H of the output shaft 15. One end (the end on the left side in the figure) of the push rod 16A is connected to a clutch operating lever (not shown) of the motorcycle. When the clutch operating lever is operated, the push rod 16A slides within the hollow portion 15H and presses the push member 16B in the second direction D2. The push rod 16A may be configured to slide within the hollow portion 15H using a servo motor. A portion of the push member 16B protrudes outward from the output shaft 15 (here, in the second direction D2) and is connected to a release bearing 18 provided on the pressure plate 70. The push rod 16A and the push member 16B are formed to be thinner than the inner diameter of the hollow portion 15H, ensuring the flow of clutch oil within the hollow portion 15H.

[0018] The clutch housing 30 is made of an aluminum alloy. The clutch housing 30 is formed in a cylindrical shape with a bottom. As shown in FIG. 1 , the clutch housing 30 has a bottom wall 31 formed in a substantially circular shape and a side wall 33 extending in a direction D from an edge of the bottom wall 31. The clutch housing 30 holds a plurality of driving-side clutch plates 20.

[0019] As shown in Fig. 1, an input gear 35 is provided on the bottom wall 31 of the clutch housing 30. The input gear 35 is fixed to the bottom wall 31 by rivets 35B via a torque damper (not shown). The input gear 35 meshes with a drive gear (not shown) that rotates when an input member of the engine is rotated. The input gear 35 rotates integrally with the clutch housing 30, independently of the output shaft 15.

[0020] The driving side clutch plate 20 is rotationally driven by the rotational drive of the input member. As shown in FIG. 1, the driving side clutch plate 20 is held on the inner circumferential surface of the side wall 33 of the clutch housing 30. The driving side clutch plate 20 is held by engaging with a notch 30C formed in the side wall 33 of the clutch housing 30. The driving side clutch plate 20 is provided so as to be displaceable along the axial direction of the clutch housing 30 (i.e., direction D). The driving side clutch plate 20 is provided so as to be rotatable integrally with the clutch housing 30.

[0021] The driving side clutch plate 20 is a member that is pressed against the driven side clutch plate 22. The driving side clutch plate 20 is formed in an annular shape. The driving side clutch plate 20 is formed by aluminum die-casting. Friction material (not shown) made of multiple pieces of paper is attached to the front and back surfaces of the driving side clutch plate 20. Grooves several hundred microns deep are formed between the friction materials to hold clutch oil.

[0022] As shown in FIG. 1 , the clutch center 40 is accommodated in the clutch housing 30. The clutch center 40 is disposed concentrically with the clutch housing 30. The clutch center 40 has a cylindrical main body 42 and a center-side flange 68 extending radially outward from the outer circumferential edge of the main body 42. The main body 42 has a portion that protrudes in the second direction D2 beyond the center-side flange 68. The clutch center 40 does not hold the driven-side clutch plate 22. The clutch center 40 is rotated together with the output shaft 15.

[0023] 2, the main body 42 includes an output shaft holding portion 50, a plurality of center-side cam portions 60, and a center-side fitting portion 58. The center-side cam portion 60 is formed to protrude in the second direction D2 beyond the center-side flange 68. The center-side cam portion 60 is located radially outward of the output shaft holding portion 50.

[0024] As shown in Figure 2, the center side flange 68 extends radially outward from the outer peripheral edge of the main body 42. The center side flange 68 is located radially outward of the center side cam portion 60. The center side flange 68, together with a pressure side flange 98 (described later) of the pressure plate 70, sandwiches the drive side clutch plates 20 and the driven side clutch plates 22. The center side flange 68 is provided so as to be able to press the drive side clutch plates 20 and the driven side clutch plates 22. The center side flange 68 is a member that applies a pressing force to the drive side clutch plates 20 and the driven side clutch plates 22.

[0025] As shown in Fig. 2, the output shaft holding portion 50 is formed in a cylindrical shape. The output shaft holding portion 50 is formed with an insertion hole 51 into which the output shaft 15 (see Fig. 1) is inserted and spline-fitted. The insertion hole 51 is formed to penetrate the main body 42. An inner circumferential surface 50A of the output shaft holding portion 50 that forms the insertion hole 51 has a plurality of spline grooves formed along the axial direction. The output shaft 15 is connected to the output shaft holding portion 50.

[0026] The center-side cam portion 60 is formed in a platform shape with a cam surface made up of an inclined surface that constitutes an Assist & Slipper (registered trademark) mechanism that generates an assist torque, which is a force that increases the pressing force (pressure contact force) between the drive-side clutch plates 20 and the driven-side clutch plates 22, or a slipper torque, which is a force that quickly separates the drive-side clutch plates 20 and the driven-side clutch plates 22, causing the clutch to transition to a partial clutch state. The partial clutch state is a state between a clutch-engaged state and a clutch-disengaged state. The center-side cam portions 60 are formed on the main body 42. The center-side cam portions 60 are arranged at equal intervals in the circumferential direction S of the clutch center 40. In this embodiment, the clutch center 40 has three center-side cam portions 60, but the number of center-side cam portions 60 is not limited to three.

[0027] As shown in FIG. 2 , the center-side cam portion 60 is located radially outward of the output shaft holding portion 50. The center-side cam portion 60 has a center-side assist cam surface 60A and a center-side slipper cam surface 60S. The center-side assist cam surface 60A is configured to generate a force (here, a first direction D1) from the pressure plate 70 toward the clutch center 40 when the clutch center 40 rotates relative to the pressure plate 70 during acceleration or other such events in order to increase the pressing force (pressure contact force) between the drive-side clutch plate 20 and the driven-side clutch plate 22. In this embodiment, when the force is generated, the position of the pressure plate 70 relative to the clutch center 40 does not change, and the pressure plate 70 does not need to physically approach the clutch center 40. Note that the pressure plate 70 may be physically displaced relative to the clutch center 40. The center-side slipper cam surface 60S is configured to move the pressure plate 70 away from the clutch center 40 in order to reduce the pressing force (pressure contact force) between the drive-side clutch plate 20 and the driven-side clutch plate 22 when the clutch center 40 rotates relative to the pressure plate 70 during deceleration, etc. In the center-side cam portions 60 adjacent to each other in the circumferential direction S, the center-side assist cam surface 60A of one center-side cam portion 60L and the center-side slipper cam surface 60S of the other center-side cam portion 60M are arranged opposite each other in the circumferential direction S.

[0028] As shown in FIG. 2, the clutch center 40 has a plurality of boss portions 54 (three in this embodiment). The boss portions 54 are members that support the pressure plate 70. The plurality of boss portions 54 are arranged at equal intervals in the circumferential direction S. The boss portions 54 are formed in a cylindrical shape. The boss portions 54 are located radially outward from the output shaft holding portion 50. The boss portions 54 extend toward the pressure plate 70 (i.e., toward the second direction D2). The boss portions 54 are provided on the main body 42. A threaded hole 54H is formed in the boss portion 54, into which a bolt (not shown) is inserted. The threaded hole 54H extends in the axial direction of the clutch center 40.

[0029] As shown in Figure 2, the clutch center 40 has a center-side cam hole 43H that penetrates the main body 42 and a portion of the center-side flange 68. The center-side cam hole 43H penetrates the main body 42 and the center-side flange 68 in direction D. The center-side cam hole 43H extends from the side of the output shaft holding portion 50 to the center-side flange 68. The center-side cam hole 43H is formed between the center-side assist cam surface 60A of the center-side cam portion 60 and the boss portion 54. When viewed in the axial direction of the clutch center 40, the center-side assist cam surface 60A and a portion of the center-side cam hole 43H overlap.

[0030] As shown in Figure 2, the center-side fitting portion 58 is provided on the main body 42. The center-side fitting portion 58 is located radially outward from the center-side cam portion 60. The center-side fitting portion 58 is located closer to the first direction D1 than the center-side cam portion 60. The center-side fitting portion 58 is configured to be slidably fitted into the pressure-side fitting portion 88 (see Figure 3).

[0031] As shown in FIG. 1 , the pressure plate 70 is housed in the clutch housing 30. The pressure plate 70 is located closer to the clutch center 40 in the second direction D2. The pressure plate 70 is provided so as to be able to move toward or away from the clutch center 40 and to rotate relative to it. The pressure plate 70 is configured to be able to press the drive-side clutch plates 20 and the driven-side clutch plates 22. The pressure plate 70 is disposed concentrically with the clutch center 40 and the clutch housing 30. As shown in FIGS. 2 and 3 , the pressure plate 70 has a cylindrical main body 72 and a pressure-side flange 98 extending radially outward from the outer circumferential edge of the main body 72. The main body 72 has a portion that protrudes in the first direction D1 beyond the pressure-side flange 98. The pressure plate 70 holds the drive-side clutch plates 20 and all of the multiple driven-side clutch plates 22 that are arranged alternately in the direction D.

[0032] The driven-side clutch plates 22 are held by spline fitting portions 76 of the pressure plate 70, which will be described later. The driven-side clutch plates 22 are held by spline fitting to fitting teeth 77 (see FIGS. 2 and 3) and spline grooves 78 (see FIGS. 2 and 3), which will be described later, of the pressure plate 70. The driven-side clutch plates 22 are provided so as to be displaceable along the axial direction of the pressure plate 70 (i.e., direction D). The driven-side clutch plates 22 are provided so as to be rotatable integrally with the pressure plate 70.

[0033] The driven-side clutch plates 22 are members that are pressed against the driving-side clutch plates 20. The driven-side clutch plates 22 are formed in an annular shape. The driven-side clutch plates 22 are formed by punching out a thin plate material made of SPCC material into an annular shape. The friction material provided on the driving-side clutch plates 20 may be provided on the driven-side clutch plates 22 instead of the driving-side clutch plates 20, or may be provided on both the driving-side clutch plates 20 and the driven-side clutch plates 22.

[0034] As shown in Figures 2 and 3, the main body 72 includes an annular base wall 73, an outer peripheral wall 75 extending from the base wall 73 in a first direction D1, a cylindrical portion 80 provided in the center of the base wall 73, a plurality of pressure side cam portions 90 connected to the base wall 73 and the outer peripheral wall 75, a pressure side fitting portion 88, a spring accommodating portion 89, and a boss portion accommodating hole 84.

[0035] As shown in FIGS. 2 and 3 , the pressure-side flange 98 extends radially outward from the outer peripheral edge of the base wall 73 of the main body 72. The pressure-side flange 98 is located radially outward of the pressure-side cam portion 90. The pressure-side flange 98, together with the center-side flange 68 of the clutch center 40, sandwiches the drive-side clutch plates 20 and the driven-side clutch plates 22. The pressure-side flange 98 is arranged to be able to press the drive-side clutch plates 20 and the driven-side clutch plates 22. The pressure-side flange 98 is a member that applies a pressing force to the drive-side clutch plates 20 and the driven-side clutch plates 22. The pressure-side flange 98 has a first flange surface 98D1 located on the first direction D1 side and a second flange surface 98D2 located on the second direction D2 side. The first flange surface 98D1 is arranged to be able to come into contact with the drive-side clutch plates 20 or the driven-side clutch plates 22. The first flange surface 98D1 is configured to be able to press (be able to press into contact with) the driving-side clutch plates 20 and the driven-side clutch plates 22. The pressure-side flange 98 is an example of a flange.

[0036] The cylindrical portion 80 is formed in a cylindrical shape. The cylindrical portion 80 is formed integrally with the pressure-side cam portion 90. The cylindrical portion 80 accommodates the tip portion 15T (see FIG. 1) of the output shaft 15. The cylindrical portion 80 accommodates the release bearing 18 (see FIG. 1). The cylindrical portion 80 is a portion that receives a pressing force from the push member 16B. The cylindrical portion 80 is a portion that receives clutch oil that flows out from the tip portion 15T of the output shaft 15.

[0037] As shown in FIG. 3 , the outer peripheral wall 75 is disposed radially outward of the cylindrical portion 80. The outer peripheral wall 75 is formed in an annular shape when viewed from the axial direction of the output shaft 15. The outer peripheral wall 75 extends in the axial direction of the output shaft 15 (i.e., direction D). A spline fitting portion 76 is provided on an outer peripheral surface 75A of the outer peripheral wall 75. The spline fitting portion 76 has a plurality of fitting teeth 77 extending in the axial direction of the pressure plate 70 (i.e., direction D) along the outer peripheral surface 75A of the outer peripheral wall 75, and a plurality of spline grooves 78 formed between adjacent fitting teeth 77 and extending in the axial direction of the pressure plate 70. The fitting teeth 77 hold all of the driven-side clutch plates 22. The fitting teeth 77 are aligned in the circumferential direction S. The fitting teeth 77 are formed at equal intervals in the circumferential direction S. The fitting teeth 77 are formed to have the same shape. The fitting teeth 77 protrude radially outward from an outer peripheral surface 75A of the outer peripheral wall 75. The plurality of spline grooves 78 are aligned in the circumferential direction S.

[0038] The pressure-side cam portion 90 is formed in a platform shape having a cam surface made up of an inclined surface that constitutes an Assist & Slipper (registered trademark) mechanism that slides on the center-side cam portion 60 to generate assist torque or slipper torque. As shown in FIG. 3 , the pressure-side cam portion 90 is formed to protrude in the first direction D1 beyond the pressure-side flange 98. The pressure-side cam portion 90 is formed to protrude in the first direction D1 from the base wall 73. The pressure-side cam portions 90 are arranged at equal intervals in the circumferential direction S of the pressure plate 70. In this embodiment, the pressure plate 70 has three pressure-side cam portions 90, but the number of pressure-side cam portions 90 is not limited to three.

[0039] As shown in FIG. 3, the pressure-side cam portion 90 is located radially outward of the cylindrical portion 80. The pressure-side cam portion 90 is located radially inward of the outer peripheral wall 75. The pressure-side cam portion 90 has a pressure-side assist cam surface 90A (see also FIG. 2) and a pressure-side slipper cam surface 90S. The pressure-side assist cam surface 90A is configured to be able to come into contact with the center-side assist cam surface 60A. The pressure-side assist cam surface 90A is configured to generate a force in a direction from the pressure plate 70 toward the clutch center 40 in order to increase the pressing force (pressing force) between the drive-side clutch plate 20 and the driven-side clutch plate 22 when the pressure plate 70 rotates relative to the clutch center 40 during acceleration, etc. The pressure-side slipper cam surface 90S is configured to be able to come into contact with the center-side slipper cam surface 60S. The pressure-side slipper cam surface 90S is configured to move the pressure plate 70 away from the clutch center 40 in order to reduce the pressing force (pressure contact force) between the drive-side clutch plate 20 and the driven-side clutch plate 22 when the pressure plate 70 rotates relative to the clutch center 40 during deceleration, etc. In the pressure-side cam portions 90 adjacent to each other in the circumferential direction S, the pressure-side assist cam surface 90A of one pressure-side cam portion 90L and the pressure-side slipper cam surface 90S of the other pressure-side cam portion 90M are arranged opposite each other in the circumferential direction S.

[0040] Here, the action of the center-side cam portion 60 and the pressure-side cam portion 90 will be described. When the engine speed increases and the rotational driving force input to the input gear 35 and the clutch housing 30 can be transmitted to the output shaft 15 via the clutch center 40, a rotational force in the first circumferential direction S1 is applied to the pressure plate 70, as shown in Fig. 5A. Therefore, due to the action of the center-side assist cam surface 60A and the pressure-side assist cam surface 90A, a force in the first direction D1 is generated on the pressure plate 70. This increases the pressing force between the driving-side clutch plate 20 and the driven-side clutch plate 22.

[0041] On the other hand, when the rotation speed of the output shaft 15 exceeds the rotation speed of the input gear 35 and the clutch housing 30 and back torque is generated, a rotational force in the first circumferential direction S1 is applied to the clutch center 40, as shown in Fig. 5B. As a result, the action of the center-side slipper cam surface 60S and the pressure-side slipper cam surface 90S moves the pressure plate 70 in the second direction D2, releasing the pressure contact force between the drive-side clutch plate 20 and the driven-side clutch plate 22. This makes it possible to avoid problems with the engine and transmission due to back torque.

[0042] As shown in FIG. 3, the pressure side fitting portion 88 is located radially outward from the cylindrical portion 80. The pressure side fitting portion 88 is located radially outward from the pressure side cam portion 90. The pressure side fitting portion 88 is located closer to the first direction D1 than the pressure side cam portion 90. The pressure side fitting portion 88 is formed on the inner peripheral surface 75B of the outer peripheral wall 75. The pressure side fitting portion 88 is configured to be slidably fitted onto the center side fitting portion 58 (see FIG. 2). A gap is formed between the pressure side fitting portion 88 and the center side fitting portion 58.

[0043] As shown in Figures 2 and 3, the pressure plate 70 has a pressure-side cam hole 73H that penetrates a portion of the base wall 73. The pressure-side cam hole 73H penetrates the base wall 73 in direction D. 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 the outer peripheral wall 75. The pressure-side cam hole 73H is formed to penetrate between adjacent pressure-side cam portions 90. The pressure-side cam hole 73H is formed to penetrate between the pressure-side assist cam surface 90A and the pressure-side slipper cam surface 90S of adjacent pressure-side cam portions 90. When viewed in the axial direction of the pressure plate 70, the pressure-side assist cam surface 90A and a portion of the pressure-side cam hole 73H overlap. Clutch oil flows from the outside of the pressure plate 270 into the pressure side cam hole 73H.

[0044] As shown in Figures 2 and 3, the boss portion accommodating hole 84 is formed in the pressure-side cam portion 90. The boss portion accommodating hole 84 is a through-hole that penetrates the pressure-side cam portion 90. The boss portion 54 (see Figure 2) is inserted into the boss portion accommodating hole 84. The boss portion accommodating hole 84 is formed in a circular shape. The boss portion accommodating hole 84 is located between the pressure-side cam hole 73H and the spring accommodating portion 89 in the circumferential direction S.

[0045] As shown in Fig. 2, the spring accommodating portion 89 is formed in the pressure-side cam portion 90. The spring accommodating portion 89 is formed so as to be recessed from the second direction D2 to the first direction D1. The spring accommodating portion 89 is formed in a circular shape. As shown in Fig. 1, the spring accommodating portion 89 accommodates the clutch spring 25.

[0046] As shown in FIG. 1 , the clutch spring 25 is located between the pressure plate 70 and the centrifugal clutch mechanism 120. The clutch spring 25 is housed in a spring housing 89. An end 25D1 of the clutch spring 25 in the first direction D1 is located on the surface side of the pressure plate 70 in the second direction D2. The end 25D1 of the clutch spring 25 in the first direction D1 is located closer to the second direction D2 than an end 77D1 of the mating tooth 77 in the first direction D1. The end 25D1 of the clutch spring 25 in the first direction D1 is located closer to the first direction D1 than a pressure-side flange 98. The clutch spring 25 biases the pressure plate 70 toward the clutch center 40 (i.e., toward the first direction D1). The clutch spring 25 is, for example, a coil spring formed by spirally winding spring steel. The clutch spring 25 presses the pressure plate 70 in accordance with the operation of the centrifugal clutch mechanism 120 (in accordance with the movement of the weight member 122, which will be described later). The clutch spring 25 is configured to press the pressure plate 70 in a first direction D1 by the weight member 122 moving from a radially inner position PI1 (see FIG. 1) to a radially outer position PO1 (see FIG. 4), thereby bringing the drive-side clutch plate 20 and the driven-side clutch plate 22 into pressure contact. The clutch spring 25 is an example of a pressing member. The radially inner position PI1 is an example of a first position. The radially outer position PO1 is an example of a second position. FIG. 1 is a cross-sectional view of the clutch device 10 showing a state in which the weight member 122 is located at the radially inner position PI1. FIG. 4 is a cross-sectional view of the clutch device 10 showing a state in which the weight member 122 is located at the radially outer position PO1.

[0047] As shown in FIG. 1, the centrifugal clutch mechanism 120 is provided at an end 30D2 on the opening side (second direction D2 side) of the clutch housing 30. The centrifugal clutch mechanism 120 is provided so as to be rotatable integrally with the clutch housing 30. The centrifugal clutch mechanism 120 is provided on the second direction D2 side of the pressure plate 70. The centrifugal clutch mechanism 120 has a plurality of weight members 122, a retaining member 124 that houses the weight members 122, and an interlocking member 130. When the weight members 122 are at a radially inner position PI1 (see FIG. 1), the centrifugal clutch mechanism 120 releases the pressure contact force between the driving-side clutch plate 20 and the driven-side clutch plate 22, thereby establishing a state in which transmission of the rotational driving force of the input member to the output shaft 15 can be blocked. When the weight member 122 is in the radially outer position PO1 (see Figure 4), the centrifugal clutch mechanism 120 presses the driving side clutch plate 20 and the driven side clutch plate 22 together, making it possible to transmit the rotational driving force of the input member to the output shaft 15.

[0048] The weight member 122 is movable from a first position PI1 (see FIG. 1 ) where the pressure between the driving-side clutch plate 20 and the driven-side clutch plate 22 is released and the rotational driving force of the input member is prevented from being transmitted to the output shaft 15 as the centrifugal force increases with the rotation of the clutch housing 30. To a second position PO1 (see FIG. 4 ) where the driving-side clutch plate 20 and the driven-side clutch plate 22 are brought into pressure contact with each other, enabling the rotational driving force of the input member to be transmitted to the output shaft 15. The weight member 122 is spherical. The weight member 122 is, for example, a steel ball. When no centrifugal force is applied, the weight member 122 is held at the radially inner position PI1 by a spring (not shown). When centrifugal force is applied, the weight member 122 moves radially outward against the biasing force of the spring (not shown) to the radially outer position PO1.

[0049] 1, the holding member 124 holds the weight member 122 movably between a radially inner position PI1 and a radially outer position PO1. The holding member 124 is provided with an abutment surface 124A against which the weight member 122 abuts when the weight member 122 moves radially. The abutment surface 124A is inclined toward the first direction D1 as it moves from the radially inner side to the radially outer side. The holding member 124 is held by engaging with a notch 30C formed in the side wall 33 of the clutch housing 30.

[0050] As shown in FIG. 1 , the interlocking member 130 is attached to the retaining member 124. The interlocking member 130 is provided so as to be displaceable along the axial direction of the clutch housing 30 (i.e., direction D). The interlocking member 130 and the retaining member 124 are provided so as to be rotatable integrally with the clutch housing 30. The interlocking member 130 holds the clutch spring 25 housed in the spring accommodating portion 89. The interlocking member 130 contacts an end 25D2 of the clutch spring 25 in the second direction D2. The interlocking member 130 holds the weight member 122 together with the retaining member 124. The interlocking member 130 is configured to be able to move in the first direction D1 as the weight member 122 moves from a radially inner position PI1 to a radially outer position PO1, thereby pressing the clutch spring 25 in the first direction D1.

[0051] In the centrifugal clutch mechanism 120 configured as described above, when no centrifugal force is applied to the weight member 122, the weight member 122 is held at a radially inner position PI1 (see FIG. 1), and the pressing force between the drive-side clutch plate 20 and the driven-side clutch plate 22 is released. On the other hand, when centrifugal force is applied to the weight member 122, the weight member 122 moves from the radially inner position PI1 to a radially outer position PO1 (see FIG. 4). As a result, the interlocking member 130 is pressed by the weight member 122 and moves in the first direction D1. When the pressing force from the weight member 122 on the interlocking member 130 cannot be absorbed by the clutch spring 25, the pressing force is transmitted to the pressure plate 70 via the clutch spring 25, and the pressure plate 70 moves in the first direction D1. As a result, the pressure side flange 98 and the center side flange 68 press the drive side clutch plate 20 and the driven side clutch plate 22 together, resulting in a pressurized state in which the rotational driving force of the input member can be transmitted to the output shaft 15.

[0052] As described above, in the clutch device 10 of this embodiment, the end 25D1 in the first direction D1 of the clutch spring 25 that presses the pressure plate 70 in response to operation of the centrifugal clutch mechanism 120 is located on the surface side of the pressure plate 70 in the second direction D2 and on the second direction D2 side of the end 77D1 in the first direction D1 of the engaging tooth 77. According to the above aspect, the pressing force from the pressure plate 70 pressed by the clutch spring 25 is more efficiently transmitted to the drive-side clutch plate 20 and the driven-side clutch plate 22. This allows the drive-side clutch plate 20 and the driven-side clutch plate 22 to be sufficiently pressed into contact with each other.

[0053] In the clutch device 10 of this embodiment, the end 25D1 of the clutch spring 25 in the first direction D1 is located closer to the first direction D1 than the pressure-side flange 98. According to the above aspect, the pressing force from the pressure plate 70 pressed by the clutch spring 25 is transmitted to the driving-side clutch plate 20 and the driven-side clutch plate 22 more efficiently.

[0054] In the clutch device 10 of this embodiment, the clutch spring 25 is located between the pressure plate 70 and the centrifugal clutch mechanism 120. According to the above aspect, power can be easily transmitted from the centrifugal clutch mechanism 120 to the pressure plate 70 via the clutch spring 25.

[0055] In the first embodiment described above, the clutch device 10 includes the clutch spring 25 as an example of a pressing member. However, this is not limiting. For example, as shown in FIG. 6 , the pressing member 25A may be located closer to the second direction D2 than the second flange surface 98D2. Here, the pressing member 25A is provided integrally with the centrifugal clutch mechanism 120. More specifically, the pressing member 25A is provided integrally with the interlocking member 130 of the centrifugal clutch mechanism 120. The pressing member 25A protrudes from the interlocking member 130 in the first direction D1. The pressing member 25A is configured to press the second flange surface 98D2. According to the above-described embodiment, the pressing force from the pressure plate 70 pressed by the pressing member 25A is more efficiently transmitted to the driving-side clutch plate 20 and the driven-side clutch plate 22. Note that, although the pressing member 25A is provided integrally with the interlocking member 130 in the example shown in FIG. 6 , the pressing member 25A may be a separate member from the interlocking member 130. Furthermore, for example, if the pressure-side flange 98 has a protrusion extending in the second direction D2, the surface of this protrusion on the second direction D2 side corresponds to the second flange surface 98D2, and the interlocking member 130 corresponds to the pressing member.

[0056] 7, the pressing member 25B may be located closer to the second direction D2 than a surface 73D2 of the base wall 73 on the second direction D2 side. Here, the pressing member 25B is provided integrally with the centrifugal clutch mechanism 120. More specifically, the pressing member 25B is provided integrally with an interlocking member 130 of the centrifugal clutch mechanism 120. The pressing member 25B protrudes from the interlocking member 130 in the first direction D1. The pressing member 25B is configured to press the surface 73D2 of the base wall 73 on the second direction D2 side. According to the above embodiment, the pressing force from the pressure plate 70 pressed by the pressing member 25B is more efficiently transmitted to the driving-side clutch plate 20 and the driven-side clutch plate 22. Note that, although the pressing member 25B is provided integrally with the interlocking member 130 in the example shown in FIG. 7, the pressing member 25B may be a separate member from the interlocking member 130. Also, for example, if the base wall 73 has a protrusion extending in the second direction D2, the surface of this protrusion on the second direction D2 side corresponds to the surface 73D2 of the base wall 73 on the second direction D2 side, and the interlocking member 130 corresponds to the pressing member.

[0057] Second Embodiment Fig. 8 is an enlarged cross-sectional view of a portion of a clutch device 210 according to the second embodiment. As shown in Fig. 8, the clutch device 210 includes an output shaft 15, a driving-side clutch plate 20, a driven-side clutch plate 22, a clutch housing 30, a clutch center 240, a pressure plate 70, and a centrifugal clutch mechanism 320.

[0058] As shown in FIG. 8, the clutch center 240 includes a first clutch center 241 and a second clutch center 242. The first clutch center 241 is connected to the output shaft 15. The first clutch center 241 includes an output shaft holding portion 50 to which the output shaft 15 is connected. The first clutch center 241 includes a plurality of center-side cam portions 60 (see FIG. 2). The second clutch center 242 is assembled to the first clutch center 241 so as to be movable in the axial direction of the output shaft 15 (i.e., direction D). The second clutch center 242 includes a center-side flange 68. The center-side flange 68 is provided on the outer periphery of the second clutch center 242. The center-side flange 68 is located between the drive-side clutch plates 20 and the driven-side clutch plates 22 and the clutch housing 30 in the axial direction of the output shaft 15 (i.e., direction D). The center-side flange 68 moves in the axial direction (here, the second direction D2) when a weight member 322, which will be described later, moves from a radially inner position PI2 (see FIG. 8) to a radially outer position PO2 (see FIG. 10), thereby pressing the driving-side clutch plate 20 and the driven-side clutch plate 22 together. The center-side flange 68 has a pressing surface 68D2 located radially outer than the fitting teeth 77. The pressing surface 68D2 is provided so as to be able to press the driving-side clutch plate 20. Note that the pressing surface 68D2 may also be provided so as to be able to press the driven-side clutch plate 22. The center-side flange 68 is an example of a pressing member. The radially inner position PI2 is an example of a first position. The radially outer position PO2 is an example of a second position.

[0059] As shown in FIG. 8, the centrifugal clutch mechanism 320 is accommodated in the clutch housing 30. The centrifugal clutch mechanism 320 is disposed on the first direction D1 side of the clutch center 240. The centrifugal clutch mechanism 320 is held in the clutch housing 30. The centrifugal clutch mechanism 320 is provided so as to be rotatable integrally with the clutch housing 30. The centrifugal clutch mechanism 320 has a plurality of weight members 322 and a holding member 324. When the weight members 322 are at a radially inner position PI2 (see FIG. 8), the centrifugal clutch mechanism 320 releases the pressure contact force between the driving-side clutch plate 20 and the driven-side clutch plate 22, thereby establishing a state in which transmission of the rotational driving force of the input member to the output shaft 15 can be blocked. When the weight member 322 is in the radially outer position PO2 (see Figure 10), the centrifugal clutch mechanism 320 presses the driving side clutch plate 20 and the driven side clutch plate 22 together, making it possible to transmit the rotational driving force of the input member to the output shaft 15.

[0060] The weight member 322 is movable from a first position PI2 (see FIG. 8) where the pressure contact force between the driving-side clutch plate 20 and the driven-side clutch plate 22 is released and the rotational driving force of the input member is prevented from being transmitted to the output shaft 15 as the centrifugal force increases with the rotation of the clutch housing 30, to a second position PO2 (see FIG. 10) where the driving-side clutch plate 20 and the driven-side clutch plate 22 are brought into pressure contact and the rotational driving force of the input member is transmittable to the output shaft 15. The weight member 322 is housed in a holding member 324. The weight member 322 includes a main body 330 formed in a substantially rectangular parallelepiped shape, a first spherical member 331, and a second spherical member 332. The first spherical member 331 and the second spherical member are attached to the main body 330. The first spherical member 331 and the second spherical member are, for example, steel balls. The first spherical member 331 is provided so as to be able to come into contact with the interlocking member 340. The second spherical member 332 is provided so as to be able to come into contact with the holding member 324. The first spherical member 331 and the second spherical member 332 are configured to be able to roll. When no centrifugal force is applied, the weight member 322 is held at a radially inner position PI2 by a spring (not shown). When centrifugal force is applied, the weight member 322 moves radially outward against the biasing force of the spring (not shown) to a radially outer position PO2.

[0061] 8, the holding member 324 holds the weight member 322 movably between a radially inner position PI2 and a radially outer position PO2. The holding member 324 has an accommodating portion 324A that accommodates the weight member 322. The holding member 324 is engaged with and held in a notch 30C formed in the side wall 33 of the clutch housing 30.

[0062] As shown in FIG. 8, the clutch device 210 includes an interlocking member 340. The interlocking member 340 is located between the drive-side clutch plate 20, the driven-side clutch plate 22, and the clutch housing 30 in the axial direction of the output shaft 15 (i.e., direction D). The interlocking member 340 is held by engaging with a notch 30C formed in the side wall 33 of the clutch housing 30. As shown in FIG. 9, the interlocking member 340 is formed in an annular shape. As shown in FIG. 8, the interlocking member 340 includes an inclined surface 340A on which the first spherical member 331 rolls. The inclined surface 340A inclines toward the first direction D1 as it moves from the radially inner side to the radially outer side. The interlocking member 340 moves in the axial direction of the output shaft 15 (here, in the second direction D2) as the weight member 322 moves from a radially inner position PI2 (see FIG. 8) to a radially outer position PO2 (see FIG. 10), thereby pressing the drive-side clutch plate 20 and the driven-side clutch plate 22 together. The interlocking member 340 is provided so as to be able to press the second clutch center 242. The interlocking member 340 and the centrifugal clutch mechanism 320 are provided so as to be able to rotate integrally with the clutch housing 30.

[0063] In the centrifugal clutch mechanism 320 configured as described above, when no centrifugal force is applied to the weight member 322, the weight member 322 is held at a radially inner position PI2 (see FIG. 8), and the pressing force between the driving-side clutch plate 20 and the driven-side clutch plate 22 is released. On the other hand, when centrifugal force is applied to the weight member 322, the weight member 322 moves from the radially inner position PI2 to a radially outer position PO2 (see FIG. 10). As a result, the interlocking member 340 is pressed by the weight member 322 and moves in the second direction D2. As the interlocking member 340 moves in the second direction D2, the second clutch center 242 is pressed against the interlocking member 340, and the second clutch center 242 moves in the second direction. As a result, the pressure side flange 98 and the center side flange 68 press the driving side clutch plate 20 and the driven side clutch plate 22 together, resulting in a pressed state, and the rotational driving force of the input member can be transmitted to the output shaft 15.

[0064] According to the clutch device 210 of this embodiment, the center-side flange 68 is located radially outward of the mating teeth 77 and has a pressing surface 68D2 that can press the drive-side clutch plates 20. According to the above aspect, the pressing force from the pressing surface 68D2 of the center-side flange 68, which moves in direction D due to the movement of the weight member 322, is efficiently transmitted to the drive-side clutch plates 20 and the driven-side clutch plates 22. This allows the drive-side clutch plates 20 and the driven-side clutch plates 22 to be sufficiently pressed together.

[0065] In the clutch device 210 of this embodiment, the clutch center 240 has a first clutch center 241 connected to the output shaft 15 and a second clutch center 242 assembled to be movable in direction D relative to the first clutch center 241, and the center-side flange 68 is provided on the outer periphery of the second clutch center 242. According to the above aspect, the pressing force from the pressing surface 68D2 of the center-side flange 68, which moves in direction D due to the movement of the weight member 322, is transmitted to the driving-side clutch plate 20 and the driven-side clutch plate 22 more efficiently.

[0066] In the second embodiment described above, the center-side flange 68 has the pressing surface 68D2 that can press the driving-side clutch plate 20, but this is not limited to this. For example, the interlocking member 340 may have a pressing surface that can press the driving-side clutch plate 20 or the driven-side clutch plate 22. Furthermore, the center-side flange 68 and the interlocking member 340 may be formed to have a uniform shape.

[0067] Although the preferred embodiments of the present invention have been described above, the above-described embodiments are merely examples, and the present invention can be embodied in various other forms.

[0068] In the above-described embodiments, the weight member 122, 322 is configured to move as a whole between a first position (a radially inner position) and a second position (a radially outer position), but this is not limited to this. For example, the weight member may be configured so that a part of the weight member swings (moves) between the first position and the second position around a support shaft that is perpendicular to the axis of the output shaft 15 and positioned radially outward of the axis of the output shaft 15. Furthermore, the ability of the weight member to move from the first position to the second position includes the case where the entire weight member is movable as described above, and the case where a part of the weight member is movable (swings). [Explanation of symbols]

[0069] 10. Clutch device 15 Output shaft (output member) 20 Drive side clutch plate 22 Driven side clutch plate 25 Clutch spring (pressure member) 30 Clutch housing 40 Clutch center 68 Center flange (pressure welding member) 70 Pressure Plate 73 Base Wall 75 Outer wall 77 Interdigitating teeth 78 Spline groove 80 Cylindrical part 84 Spring housing 98 Pressure side flange 120 Centrifugal clutch mechanism 122 Weight member 124 Retaining member 130 Interlocking members

Claims

1. A clutch device that transmits or interrupts the rotational drive force of an input member to an output member, a clutch center accommodated in a clutch housing that holds a plurality of drive-side clutch plates that are rotationally driven by the rotational drive of the input member, and that is rotationally driven together with the output member; a pressure plate that is provided so as to be able to approach or move away from the clutch center, that holds all of the plurality of driven-side clutch plates that are arranged alternately with the driving-side clutch plates, and that can press the driving-side clutch plates and the driven-side clutch plates; a centrifugal clutch mechanism having a plurality of weight members that are movable from a first position where the pressure contact force between the drive-side clutch plate and the driven-side clutch plate is released and transmission of the rotational driving force of the input member to the output member is interrupted as centrifugal force increases with rotation of the clutch housing, to a second position where the drive-side clutch plate and the driven-side clutch plate are brought into pressure contact with each other, enabling transmission of the rotational driving force of the input member to the output member; a pressure contact member located between the driving side clutch plate and the driven side clutch plate and the clutch housing in the axial direction of the output member, when a direction in which the pressure plate approaches the clutch center is defined as a first direction and a direction in which the pressure plate moves away from the clutch center is defined as a second direction, the pressure contact member moves in the axial direction toward the second direction as the weight member moves from the first position to the second position, thereby bringing the driving side clutch plate and the driven side clutch plate into pressure contact, The pressure plate is an outer peripheral wall extending in the axial direction of the output member and formed in an annular shape when viewed in the axial direction of the output member; a plurality of engaging teeth arranged in a circumferential direction, the engaging teeth holding all of the driven-side clutch plates and formed to protrude radially outward from the outer peripheral surface of the outer peripheral wall; a plurality of spline grooves formed between adjacent mating teeth, The pressure contact member is a pressing surface located radially outward of the engaging teeth and capable of pressing the driving-side clutch plate or the driven-side clutch plate, The clutch center is a first clutch center connected to the output member; a second clutch center assembled to the first clutch center so as to be movable in the axial direction, The pressure contact member is provided on an outer periphery of the second clutch center.

2. 2. The clutch device according to claim 1, wherein an end surface of the engaging tooth on the first direction side faces a surface of the second clutch center on the second direction side.

Images