Power transmission device

Abstract

To provide a power transmission device capable of increasing a clutch capacity while avoiding an increase in the axial size of the device.SOLUTION: An auxiliary clutch plate 17 having a diameter different from that of each of a driving side clutch plate 6 and a driven side clutch plate 7 is arranged on a clutch housing 2. When the driving side clutch plate 6 and the driven side clutch plate 7 have pressure contact with each other, the auxiliary clutch plate 17 has pressure contact with them to put the driving force of an engine E in the state of being transmitted to driving wheels T, and when the driving side clutch plate 6 and the driven side clutch plate 7 are released from pressure contact force, the pressure contact force of the auxiliary clutch plate 17 is released to cut off the driving force of the engine E from being transmitted to the driving wheels T.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a power transmission device capable of arbitrarily transmitting or blocking the rotational force of an input member to an output member.

Background Art

[0002] Generally, a power transmission device provided in a motorcycle is for arbitrarily transmitting or blocking the driving force of an engine to a transmission and a driving wheel, and includes an input member connected to the engine side, an output member connected to the transmission and the driving wheel side, a clutch member connected to the output member, and a pressure member capable of approaching or separating from the clutch member. By bringing the pressure member close to the clutch member, the driving-side clutch plate and the driven-side clutch plate are brought into pressure contact to transmit power, and by separating the pressure member from the clutch member, the pressure contact force between the driving-side clutch plate and the driven-side clutch plate is released to block the transmission of the power.

[0003] As a conventional power transmission device, for example, as disclosed in Patent Document 1, there has been proposed a centrifugal clutch means including a weight member that can move from an inner diameter side position to an outer diameter side position of the groove portion by centrifugal force accompanying the rotation of a clutch housing, thereby bringing the driving-side clutch plate and the driven-side clutch plate into pressure contact. According to such a conventional power transmission device, when the clutch housing rotates with the driving of the engine, centrifugal force can be applied to the weight member, and the driving-side clutch plate and the driven-side clutch plate can be brought into pressure contact to transmit the driving force of the engine to the wheels.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in order to achieve the clutch capacity required for the multi-plate clutch, it may be necessary to increase the number of driving-side clutch plates and driven-side clutch plates. In that case, if the driving-side clutch plates and the driven-side clutch plates are simply increased in the stacking direction of the multi-plate clutch to cope with it, the device will become larger in the axial direction, and there is a risk of exceeding the installable space for the vehicle. Note that such a problem may occur not only in those equipped with weight members, but also in general multi-plate clutch type power transmission devices having driving-side clutch plates and driven-side clutch plates.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a power transmission device capable of increasing the clutch capacity while avoiding an increase in the size of the device in the axial direction.

Means for Solving the Problems

[0007] The invention according to claim 1 is a clutch member housed in a clutch housing that rotates together with an input member rotated by the driving force of an engine of a vehicle, and to which a plurality of driving-side clutch plates are attached. A spline fitting portion into which the inner peripheral edges of a plurality of driven-side clutch plates formed alternately with the driving-side clutch plates are fitted is formed on the outer peripheral surface. The clutch member is connected to an output member capable of rotating a wheel of the vehicle. A pressure member that can move between an operating position in which the driving-side clutch plate and the driven-side clutch plate are pressed against each other to transmit the driving force of the engine to the wheel, and a non-operating position in which the pressing force between the driving-side clutch plate and the driven-side clutch plate is released to block the transmission of the driving force of the engine to the wheel. An auxiliary clutch plate having a diameter smaller than the diameter of the inner peripheral edge of the driven-side clutch plate is disposed on the output member. When the driving-side clutch plate and the driven-side clutch plate are pressed against each other, the auxiliary clutch plate is pressed against to enable the driving force of the engine to be transmitted to the wheel. When the pressing force between the driving-side clutch plate and the driven-side clutch plate is released, the pressing force of the auxiliary clutch plate is released to block the transmission of the driving force of the engine to the wheel.

[0008] The invention according to claim 2 is the power transmission device according to claim 1, further comprising a weight member that can move from an inner diameter side position to an outer diameter side position by centrifugal force accompanying the rotation of the clutch housing. When the weight member is in the outer diameter side position, the driving-side clutch plate and the driven-side clutch plate are pressed against each other and the auxiliary clutch plate is pressed against to enable the driving force of the engine to be transmitted to the wheel. When the weight member is in the inner diameter side position, the pressing force between the driving-side clutch plate and the driven-side clutch plate is released and the pressing force of the auxiliary clutch plate is released to block the transmission of the driving force of the engine to the wheel. It has centrifugal clutch means.

[0009] The invention according to claim 3 is characterized in that, in the power transmission device according to claim 2, at least a part of the centrifugal clutch means is located between the auxiliary clutch plate, the drive-side clutch plate, and the driven-side clutch plate. The invention according to claim 4 is characterized in that, in the power transmission device according to claim 2 or 3, the centrifugal clutch means includes a holding member that movably holds the weight member between the inner diameter side position and the outer diameter side position, a pressing member that moves in the stacking direction of the drive-side clutch plate and the driven-side clutch plate when the weight member moves from the inner diameter side position to the outer diameter side position to press the drive-side clutch plate and the driven-side clutch plate together, and a biasing member for biasing the weight member from the outer diameter side position toward the inner diameter side position. When the weight member is at the outer diameter side position, one of the pressing member and the holding member presses the drive-side clutch plate and the driven-side clutch plate together, and the other of the pressing member and the holding member presses the auxiliary clutch plate.

[0010] The invention according to claim 5 is characterized in that, in the power transmission device according to any one of claims 1 to 4, the stacked portion of the drive-side clutch plate and the driven-side clutch plate and the auxiliary clutch plate are arranged to be offset from each other in the axial direction of the clutch housing.

[0011] The invention according to claim 6 is characterized in that, in the power transmission device according to any one of claims 1 to 5, the auxiliary clutch plate is composed of a plurality of clutch plates. The invention according to claim 7 is a clutch member housed in a clutch housing that rotates together with an input member rotated by the driving force of an engine of a vehicle, and to which a plurality of driving-side clutch plates are attached. A plurality of driven-side clutch plates formed alternately with the driving-side clutch plates are attached, and the clutch member is connected to an output member capable of rotating a wheel of the vehicle. An operating position for bringing the driving-side clutch plate and the driven-side clutch plate into pressure contact to transmit the driving force of the engine to the wheel, and a non-operating position for releasing the pressure contact force between the driving-side clutch plate and the driven-side clutch plate to block the transmission of the driving force of the engine to the wheel. A pressure member movable between them, an auxiliary clutch plate disposed on the output member, and a weight member movable from an inner diameter side position to an outer diameter side position by centrifugal force accompanying the rotation of the clutch housing. It is a power transmission device comprising centrifugal clutch means provided between the driving-side clutch plate, the driven-side clutch plate, and the auxiliary clutch plate. When the weight member is in the outer diameter side position, the driving-side clutch plate and the driven-side clutch plate are brought into pressure contact and the auxiliary clutch plate is brought into pressure contact to enable the driving force of the engine to be transmitted to the wheel. When the weight member is in the inner diameter side position, the pressure contact force between the driving-side clutch plate and the driven-side clutch plate is released and the pressure contact force of the auxiliary clutch plate is released to block the transmission of the driving force of the engine to the wheel. The invention according to claim 8 is the power transmission device according to claim 7, wherein a spline fitting portion into which the inner peripheral edge of the driven-side clutch plate fits is formed on the outer peripheral surface of the clutch member, and the diameter of the auxiliary clutch plate is smaller than the diameter of the inner peripheral edge of the driven-side clutch plate. The invention according to claim 9 is the power transmission device according to claim 7 or 8, wherein the auxiliary clutch plate overlaps at least a part of the centrifugal clutch means when viewed from the radial direction of the output member.

Effects of the Invention

[0012] According to the invention of claim 1, an auxiliary clutch plate having a different diameter from the driving-side clutch plate and the driven-side clutch plate is disposed in the clutch housing. When the driving-side clutch plate and the driven-side clutch plate are pressed against each other, the auxiliary clutch plate is pressed against to make the driving force of the engine transmissible to the wheels, and when the pressing force between the driving-side clutch plate and the driven-side clutch plate is released, the pressing force of the auxiliary clutch plate is released to block the transmission of the driving force of the engine to the wheels. Therefore, it is possible to increase the clutch capacity while avoiding an increase in the size of the device in the axial direction.

[0013] According to the invention of claim 2, when the weight member is at the outer diameter side position, the driving-side clutch plate and the driven-side clutch plate are pressed against each other, and at the same time, the auxiliary clutch plate is pressed against to make the driving force of the engine transmissible to the wheels. When the weight member is at the inner diameter side position, the pressing force between the driving-side clutch plate and the driven-side clutch plate is released, and at the same time, the pressing force of the auxiliary clutch plate is released to block the transmission of the driving force of the engine to the wheels. Since it has a centrifugal clutch means, by the centrifugal clutch means, in addition to the pressing or release of the pressing force of the driving-side clutch plate and the driven-side clutch plate, the pressing or release of the pressing force of the auxiliary clutch plate can be performed.

[0014] According to the invention of claim 4, when the weight member is at the outer diameter side position, one of the pressing member and the holding member presses the driving-side clutch plate and the driven-side clutch plate against each other, and the other of the pressing member and the holding member presses the auxiliary clutch plate against. Therefore, by the pressing member and the holding member constituting the centrifugal clutch means, in addition to the pressing or release of the pressing force of the driving-side clutch plate and the driven-side clutch plate, the pressing or release of the pressing force of the auxiliary clutch plate can be performed.

[0015] According to the invention of claim 5, the laminated portions of the driving-side clutch plate and the driven-side clutch plate and the auxiliary clutch plate are arranged to be offset from each other in the axial direction of the clutch housing. Therefore, an increase in the size of the device in the axial direction can be surely avoided.

[0016] According to the invention of claim 6, since the auxiliary clutch plate is composed of a plurality of clutch plates, the clutch capacity of the auxiliary clutch plate can be arbitrarily increased.

Brief Description of the Drawings

[0017]

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Best Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. As shown in FIG. 21, the power transmission device K according to the present embodiment is disposed in a vehicle and is for arbitrarily transmitting or interrupting the driving force of the engine E to the driving wheel T side via the transmission M. As shown in FIGS. 1 to 17, a clutch housing 2 in which an input gear 1 (input member) rotated by the driving force of the engine E of the vehicle is formed, an output shaft 3 (output member) connected to the transmission M, a clutch member (first clutch member 4a and second clutch member 4b), a pressure member 5, a plurality of driving-side clutch plates 6 and a plurality of driven-side clutch plates 7, and a centrifugal clutch means 9 including a weight member 10 and an auxiliary clutch plate 17 are provided.

[0019] The input gear 1 is rotatable about the output shaft 3 when the driving force (rotational force) transmitted from the engine E is input, and is connected to the clutch housing 2 by a rivet or the like. The clutch housing 2 is formed of a cylindrical member having an open right end side in FIGS. 2 and 3 and is connected to the input gear 1 so as to be rotatable together with the rotation of the input gear 1 by the driving force of the engine E.

[0020] Further, as shown in FIG. 4, the clutch housing 2 is formed with a plurality of notches 2a extending in the circumferential direction, and a plurality of driving-side clutch plates 6 are fitted into these notches 2a and attached. Each of the driving-side clutch plates 6 is formed of a plate material formed in a substantially annular shape, rotates together with the rotation of the clutch housing 2, and is configured to be slidable in the axial direction (the left-right direction in FIGS. 2 and 3).

[0021] The clutch members (the first clutch member 4a and the second clutch member 4b) have a plurality of driven clutch plates 7 alternately formed with the drive-side clutch plate 6 of the clutch housing 2 attached thereto, and are connected to an output shaft 3 (output member) that can rotate the drive wheels T via the vehicle's transmission M. The clutch members are composed of two members, the first clutch member 4a and the second clutch member 4b, assembled together.

[0022] The first clutch member 4a is configured such that the output shaft 3 is inserted through an insertion hole formed at its center (see FIGS. 5 and 6), and gears formed thereon mesh with each other and are connected in the rotational direction. As shown in FIGS. 5 and 6, the first clutch member 4a is formed with a gradient surface 4aa that constitutes a cam for pressing assist and a gradient surface 4ab that constitutes a cam for back torque limiter. In the figure, reference numeral 4ac indicates a boss portion in which an insertion hole for a bolt B for connecting the first clutch member 4a and the fixing member 8 is formed.

[0023] The second clutch member 4b is, as shown in FIGS. 7 and 8, an annular member formed with a flange portion 4bb, and the driven clutch plate 7 is configured to be attached to a spline fitting portion 4ba formed on the outer peripheral surface by spline fitting. As shown in FIGS. 2 and 3, a pressure member 5 is assembled to the clutch members (the first clutch member 4a and the second clutch member 4b), and a plurality of drive-side clutch plates 6 and driven clutch plates 7 are alternately stacked between the flange portion 5c of the pressure member 5 and the flange portion 4bb of the second clutch member 4b.

[0024] The pressure member 5 is, as shown in FIGS. 9 and 10, a disc-shaped member formed with a flange portion 5c across its peripheral edge, and is movable between an operating position where the drive-side clutch plate 6 and the driven clutch plate 7 are pressed together to enable the driving force of the engine E to be transmitted to the wheels, and a non-operating position where the pressing force between the drive-side clutch plate 6 and the driven clutch plate 7 is released to cut off the transmission of the driving force of the engine E to the wheels.

[0025] More specifically, as shown in FIGS. 7 and 8, the spline fitting portion 4ba formed on the second clutch member 4b is configured by an uneven shape integrally formed over substantially the entire circumference on the outer peripheral side surface of the second clutch member 4b. When the driven clutch plate 7 is fitted into the concave groove constituting the spline fitting portion 4ba, axial movement of the driven clutch plate 7 relative to the second clutch member 4b is allowed while rotational movement is restricted, and it is configured to be able to rotate together with the second clutch member 4b.

[0026] Such a driven clutch plate 7 is alternately laminated with the driving clutch plate 6, and adjacent clutch plates 6 and 7 can be pressed against each other or the pressing force can be released. That is, both clutch plates 6 and 7 are allowed to slide in the axial direction of the second clutch member 4b. When the clutch is turned on by pressing each clutch plate (6a, 6b, 7a, 7b) against each other, the rotational force of the clutch housing 2 is transmitted to the output shaft 3 via the second clutch member 4b and the first clutch member 4a. When the pressing force of each clutch plate (6a, 6b, 7a, 7b) is released and the clutch is turned off, the first clutch member 4a and the second clutch member 4b no longer follow the rotation of the clutch housing 2, and the rotational force is no longer transmitted to the output shaft 3.

[0027] Thus, in a state where the driving clutch plate 6 and the driven clutch plate 7 are pressed against each other, the rotational force (driving force of the engine E) input to the clutch housing 2 is transmitted to the drive wheel side (transmission M) via the output shaft 3 (output member), and in a state where the pressing of the driving clutch plate 6 and the driven clutch plate 7 is released, the rotational force (driving force of the engine E) input to the clutch housing 2 can be blocked from being transmitted to the output shaft 3 (output member).

[0028] Further, as shown in FIGS. 9 and 10, the pressure member 5 has a plurality (three in this embodiment) of fitting holes 5d formed over the circumferential direction, and a clutch spring S is fitted in each of the fitting holes 5d. As shown in FIG. 2, such a clutch spring S is housed in the fitting hole 5d while one end thereof abuts against the fixing member 8, and is biased in a direction to press the driving-side clutch plate 6 and the driven-side clutch plate 7. Then, by operating clutch operating means (not shown), the driving-side clutch plate 6 and the driven-side clutch plate 7 can be pressed or the pressing can be released.

[0029] Furthermore, in this embodiment, as shown in FIGS. 5, 6, 9, and 10, the first clutch member 4a is formed with gradient surfaces 4aa and 4ab, and the pressure member 5 is formed with gradient surfaces 5a and 5b facing these gradient surfaces 4aa and 4ab. That is, the gradient surface 4aa and the gradient surface 5a abut against each other to form a cam for pressure contact assist, and the gradient surface 4ab and the gradient surface 5b abut against each other to form a cam for back torque limiter.

[0030] When the engine speed increases and the rotational force input to the input gear 1 and the clutch housing 2 can be transmitted to the output shaft 3 via the first clutch member 4a and the second clutch member 4b (the weight member 10 is at the outer diameter side position), as shown in FIG. 20(a), since a rotational force in the a direction is applied to the pressure member 5, a force in the c direction in the figure is generated in the pressure member 5 due to the action of the cam for pressure contact assist. As a result, the pressure member 5 moves in a direction closer to the flange portion 4bb of the second clutch member 4b (the left side in FIGS. 2 and 3) by its flange portion 5c, and the pressing force between the driving-side clutch plate 6 and the driven-side clutch plate 7 is increased.

[0031] On the other hand, when the rotation of the output shaft 3 causes a back torque exceeding the rotational speeds of the input gear 1 and the clutch housing 2, as shown in Fig. 20(b), a rotational force in the b direction is applied to the clutch member 4. Therefore, due to the action of the cam for the back torque limiter, the pressure member 5 is moved in the d direction in the figure to release the pressure contact force between the driving clutch plate 6 and the driven clutch plate 7. As a result, problems with the power transmission device K and the power source (engine E side) caused by the back torque can be avoided.

[0032] As shown in Figs. 11 to 19, the centrifugal clutch means 9 includes a weight member 10 that is movable from an inner diameter side position (see Fig. 18) to an outer diameter side position (see Fig. 19) by centrifugal force associated with the rotation of the clutch housing 2. When the weight member 10 is at the outer diameter side position, the driving clutch plate 6 and the driven clutch plate 7 are brought into pressure contact to enable the driving force of the engine E to be transmitted to the wheels (driving wheels T). When the weight member 10 is at the inner diameter side position, the pressure contact force between the driving clutch plate 6 and the driven clutch plate 7 is released to block the transmission of the driving force of the engine E to the wheels (driving wheels T).

[0033] Specifically, the centrifugal clutch means 9 is composed of a weight member 10 formed of piece-shaped members, a holding member 11 to which a support member 13 is attached, a pressure contact member 12, a first spherical member 14, a second spherical member 15, and a biasing member 16 composed of a coil spring. The holding member 11 and the pressure contact member 12 are each formed with a plurality of protrusions extending in the circumferential direction and are fitted and attached to the notch 2a of the clutch housing 2 in the same manner as the driving clutch plate 6. As a result, the holding member 11 and the pressure contact member 12 are each movable in the axial direction of the clutch housing 2 and are engaged in the rotational direction to be rotatable together with the clutch housing 2.

[0034] As shown in Fig. 16, the weight member 10 is composed of a piece-shaped member having one surface X and the other surface Y. As shown in Figs. 16 and 17, it is configured to have a through-hole 10a formed to penetrate from one surface X to the other surface Y, an insertion portion 10b formed on the other surface Y, and a groove 10c formed on one surface X. Such a weight member 10 is housed in the housing portion 11a of the holding member 11 as shown in Figs. 18 and 19, and is held at the inner diameter side position (see Fig. 18) in a state where no centrifugal force is applied, and moves outward against the biasing force of the biasing member 16 when centrifugal force is applied, so as to reach the outer diameter side position (see Fig. 19).

[0035] The holding member 11 is configured to hold the weight member 10 so as to be movable between the inner diameter side position and the outer diameter side position. As shown in Fig. 13, it is composed of an annular member, and a plurality of housing portions 11a for housing the weight member 10 are formed over the circumferential direction, and has a groove shape 11b formed in the housing portion 11a and a pressing surface 11c. Each housing portion 11a has a concave shape that matches the shape and movement range of the weight member 10, and one end of the biasing member 16 is configured to be able to abut against the inner peripheral wall surface 11aa thereof.

[0036] Further, the support member 13 is fixed to the surface of the holding member 11 where the housing portion 11a is formed. As shown in Fig. 14, such a support member 13 is formed with a holding portion 13a formed in the radial direction, and the weight member 10 is held by the holding member 11 by the holding portion 13a matching the groove 10c of the weight member 10. That is, the weight member 10 has a groove 10c formed in the direction from the inner diameter side position to the outer diameter side position at the central position of one surface X thereof, and by matching the holding portion 13a with the groove 10c, it is held so as to be movable in the radial direction (the direction from the inner diameter side position to the outer diameter side position).

[0037] The pressing member 12 moves in the stacking direction of the driving clutch plate 6 and the driven clutch plate 7 (the right side in FIGS. 2 and 3) when the weight member 10 moves from the inner diameter side position to the outer diameter side position, and presses the driving clutch plate 6 and the driven clutch plate 7 together. Specifically, as shown in FIG. 15, the pressing member 12 is formed of an annular member, and has a plurality of gradient grooves 12a formed over the circumferential direction, groove shapes 12b respectively formed at the positions where the gradient grooves 12a are formed, and a pressing surface 12c.

[0038] The gradient grooves 12a are respectively formed at positions corresponding to the weight member 10, and are upwardly sloped from the inside to the outside. Thereby, in a state where the clutch housing 2 is stopped, the weight member 10 is held at the inner diameter side position by the biasing force of the biasing member 16, and when the clutch housing 2 rotates, centrifugal force is applied to the weight member 10, and the pressing member 12 moves in a direction away from the holding member 11 (that is, the direction in which the driving clutch plate 6 and the driven clutch plate 7 are pressed together) by moving along the upwardly sloped gradient grooves 12a.

[0039] When the holding member 11 and the pressing member 12 are assembled with the weight member 10 interposed therebetween, as shown in FIGS. 11 and 12, the gradient grooves 12a are positioned corresponding to the respective weight members 10. Due to centrifugal force, the weight member 10 moves from the inner diameter side position to the outer diameter side position along the gradient grooves 12a, so that the pressing member 12 moves in the direction of the arrow in FIG. 11 (the right side in the figure). The pressing surface 12c formed on the pressing member 12 presses the driving clutch plate 6 and the driven clutch plate 7 to bring them into a pressed state, and the holding member 11 moves in the direction opposite to the arrow in FIG. 11 (the left side in the figure) by the reaction force, and the pressing surface 11c formed on the holding member 11 presses the auxiliary clutch plate 17.

[0040] As shown in FIGS. 18 and 19, the weight member 10 according to this embodiment is respectively housed in a plurality of housing portions 11a formed across the circumferential direction of the holding member 11 and is movable in the radial direction. The biasing members 16 are arranged in plural in the circumferential direction (two by two in this embodiment) between the inner peripheral wall surface 11aa (see FIG. 13) of the housing portion 11a and the weight member 10, and bias the weight member 10 from the outer diameter side position toward the inner diameter side position. Here, the inner peripheral wall surface 11aa of the housing portion 11a is a flat surface that abuts against one end of the biasing member 16, and the biasing member 16 can be attached in a stable state.

[0041] Further, the weight member 10 according to this embodiment is formed with a tunnel-shaped insertion portion 10b through which the biasing member 16 can be inserted while opening the surface facing the holding member 11 (the other surface Y in FIG. 17). Then, by housing the weight member 10 with the biasing member 16 inserted into the insertion portion 10b in the housing portion 11a of the holding member 11, the biasing member 16 is interposed between the inner peripheral wall surface 11aa of the housing portion 11a and the weight member 10 and attached. Note that one end of the biasing member 16 abuts against the inner peripheral wall surface 11aa while the other end abuts against the end wall surface 10ba of the insertion portion 10b, so that the weight member 10 can be biased from the outer diameter side position toward the inner diameter side position.

[0042] The first spherical member 14 is composed of a steel ball attached to the weight member 10. As shown in FIGS. 16 and 17, a part of the first spherical member 14 protrudes from one opening 10aa (the small-diameter opening on one surface X side) of the through-hole 10a formed in the weight member 10 and contacts the rolling surface of the pressing member 12 to be rollable. The second spherical member 15 is composed of a steel ball attached to the weight member 10. As shown in FIGS. 16 and 17, a part of the second spherical member 15 protrudes from the other opening 10ab (the large-diameter opening on the other surface Y side) of the through-hole 10a formed in the weight member 10 and contacts the rolling surface of the holding member 11 to be rollable.

[0043] As shown in Fig. 17, the through hole 10a according to this embodiment is formed in a tapered shape such that the diameter continuously increases from one opening 10aa (the small-diameter opening on one surface X side) to the other opening 10ab (the large-diameter opening on the other surface Y side). The first spherical member 14 is retained at the outer peripheral edge of the small-diameter opening (in this embodiment, the one opening 10aa on one surface X side) among the one opening 10aa and the other opening 10ab. That is, the first spherical member 14 and the second spherical member 15 according to this embodiment are spherical members with different diameters corresponding to the inner diameter of the through hole 10a (the second spherical member 15 has a larger diameter than the first spherical member 14). The small-diameter first spherical member 14 is retained at the opening edge on the small-diameter side of the through hole 10a and is capable of rolling while being in contact with the inner peripheral surface of the through hole 10a respectively.

[0044] On the other hand, as shown in Figs. 11 and 12, the second spherical member 15 is retained on the rolling surface of the holding member 11. Thereby, the small-diameter first spherical member 14 is retained at the opening edge on the small-diameter side of the through hole 10a, and the large-diameter second spherical member 15 is retained on the rolling surface of the holding member 11 while partially protruding from the opening on the large-diameter side of the through hole 10a. In this embodiment, the large-diameter second spherical member 15 is assembled facing the rolling surface of the holding member 11, but the second spherical member 15 may be assembled facing the rolling surface of the pressure contact member 12. In this case, the small-diameter first spherical member 14 is retained at the opening edge on the small-diameter side of the through hole 10a, and the large-diameter second spherical member 15 is retained on the rolling surface of the pressure contact member 12 while partially protruding from the opening on the large-diameter side of the through hole 10a.

[0045] However, as shown in Fig. 13, the rolling surface of the holding member 11 (in this embodiment, the rolling surface of the second spherical member 15) is formed of a groove shape 11b along the moving direction of the weight member 10 (the direction connecting the inner diameter side position and the outer diameter side position), and as shown in Fig. 15, the rolling surface of the pressure contact member 12 (in this embodiment, the rolling surface of the first spherical member 14) is formed of a groove shape 12b along the moving direction of the weight member 10 (the direction connecting the inner diameter side position and the outer diameter side position).

[0046] Furthermore, as shown in FIGS. 16, 18, and 19, the first spherical member 14 and the second spherical member 15 according to the present embodiment are each formed in a plurality (two in the present embodiment for both the first spherical member 14 and the second spherical member 15) across the circumferential direction of the holding member 11 (the width direction of the weight member 10). As the weight member 10 moves, the first spherical member 14 and the second spherical member 15 can roll within the through hole 10a and move along the groove shapes 11b and 12b, respectively.

[0047] The auxiliary clutch plate 17 is disposed within the clutch housing 2 and is formed of an annular member having a different diameter (a smaller diameter than the driving-side clutch plate 6 and the driven-side clutch plate 7 in the present embodiment). As shown in FIGS. 2 and 3, the output shaft 3 (output member) is inserted through the central opening 17a thereof and is in a fitted state, and it is configured to have a pressed surface 17b facing the pressing surface 11c of the holding member 11.

[0048] When the weight member 10 is at the outer diameter side position (that is, when the driving-side clutch plate 6 and the driven-side clutch plate 7 are in a pressure contact state), when the auxiliary clutch plate 17 is pressed and pressure contacted by the pressing surface 11c formed on the holding member 11, the driving force of the engine E can be transmitted to the output shaft 3. Further, when the weight member 10 is at the inner diameter side position (that is, when the pressing force between the driving-side clutch plate 6 and the driven-side clutch plate 7 is in a released state), when the pressing force by the pressing surface 11c formed on the holding member 11 decreases and the pressure contact force is released, the transmission of the driving force of the engine E to the output shaft 3 can be blocked.

[0049] That is, when the weight member 10 moves to the outer diameter side position, the gradient groove 12a functions as a cam, and the holding member 11 and the pressure contact member 12 move in a direction away from each other. As a result, the pressing surface 12c of the pressure contact member 12 presses the driving side clutch plate 6 and the driven side clutch plate 7, and the pressing surface 11c of the holding member 11 presses and comes into pressure contact with the pressed surface 17b of the auxiliary clutch plate 17. Therefore, the driving force of the engine E is transmitted to the drive wheel T.

[0050] Furthermore, as shown in FIGS. 5 and 6, the first clutch member 4a according to the present embodiment has a contact surface 4ad formed on a part of the surface facing the pressure member 5. As shown in FIGS. 9 and 10, the pressure member 5 has a contact surface 5e formed on a part of the surface facing the first clutch member 4a. In a state where the first clutch member 4a, the second clutch member 4b, and the pressure member 5 are assembled (a state where there is no transmission torque from the input gear 1 (input member) to the output shaft 3 (output member)), as shown in FIGS. 2 and 3, the contact surface 4ad and the contact surface 5e are in a contact state.

[0051] In this way, in a state where the contact surface 4ad and the contact surface 5e are in contact, when the weight member 10 of the centrifugal clutch means 9 moves from the inner diameter side position (see FIG. 22) to the intermediate position (see FIG. 23) and the transmission torque from the input gear 1 (input member) to the output shaft 3 (output member) increases, relative movement between the first clutch member 4a and the pressure member 5 is not allowed. Therefore, the operation of the cam for pressing assist is restricted.

[0052] Thereafter, the weight member 10 of the centrifugal clutch means 9 further moves from the intermediate position (see FIG. 23) toward the outer diameter side position (see FIG. 24), is pressed against the flange portion 4bb of the second clutch member 4b, and the drive side clutch plate 6 and the driven side clutch plate 7 are brought into pressure contact. When the pressing force of the flange portion 4bb becomes equal to or greater than the biasing force of the clutch spring S, the second clutch member 4b and the pressure member 5 are moved in the axial direction (right direction in FIGS. 2 and 3) with respect to the first clutch member 4a, and the contact surface 4ad of the first clutch member 4a and the contact surface 5e of the pressure member 5 are separated. Note that FIG. 25 shows a state where the weight member 10 is at the outer diameter side position and the pressure member 5 is at the non-operating position (clutch-off state).

[0053] Thus, in a state where the contact surface 4ad and the contact surface 5e are separated, during the process in which the weight member 10 of the centrifugal clutch means 9 moves from the inner diameter side position to the outer diameter side position and the transmission torque from the input gear 1 (input member) to the output shaft 3 (output member) increases, relative movement between the first clutch member 4a and the pressure member 5 is allowed, so the operation of the pressure contact assist cam is allowed.

[0054] That is, according to the present embodiment, when the drive side clutch plate 6 and the driven side clutch plate 7 are pressed together, the auxiliary clutch plate 17 is pressed together to enable the driving force of the engine E to be transmitted to the wheels (drive wheels T), and when the pressing force between the drive side clutch plate 6 and the driven side clutch plate 7 is released, the pressing force of the auxiliary clutch plate 17 is released to block the transmission of the driving force of the engine E to the wheels (drive wheels T).

[0055] More specifically, in the present embodiment, centrifugal clutch means 9 including a weight member 10 is disposed. When the weight member 10 is at an outer diameter side position, the driving clutch plate 6 and the driven clutch plate 7 are pressed against each other, and at the same time, the auxiliary clutch plate 17 is pressed against to make the driving force of the engine E transmissible to the wheels (driving wheels T). When the weight member 10 is at an inner diameter side position, the pressing force between the driving clutch plate 6 and the driven clutch plate 7 is released, and at the same time, the pressing force of the auxiliary clutch plate 17 is released so as to block the transmission of the driving force of the engine E to the wheels (driving wheels T).

[0056] In particular, in the present embodiment, when the weight member 10 is at an outer diameter side position, the pressing member 12 and the holding member 11 move in a direction away from each other, the pressing member 12 presses the driving clutch plate 6 and the driven clutch plate 7 against each other, and the holding member 11 presses the auxiliary clutch plate 17 against. When the weight member 10 is at an outer diameter side position, the pressing member 12 and the holding member 11 move in a direction away from each other, the holding member 11 presses the driving clutch plate 6 and the driven clutch plate 7 against each other, and the centrifugal clutch means 9 may be disposed such that the pressing member 12 presses the auxiliary clutch plate 17 against.

[0057] According to the present embodiment, an auxiliary clutch plate 17 having a different diameter from the driving clutch plate 6 and the driven clutch plate 7 is disposed in the clutch housing 2. When the driving clutch plate 6 and the driven clutch plate 7 are pressed against each other, the auxiliary clutch plate 17 is pressed against to make the driving force of the engine E transmissible to the wheels (driving wheels T). When the pressing force between the driving clutch plate 6 and the driven clutch plate 7 is released, the pressing force of the auxiliary clutch plate 17 is released to block the transmission of the driving force of the engine E to the wheels (driving wheels T). Therefore, the clutch capacity can be increased while avoiding an increase in the axial size of the device.

[0058] In particular, the auxiliary clutch plate 17 according to the present embodiment is disposed on the inner diameter side of the laminated portion (multi-plate clutch portion) of the driving-side clutch plate 6 and the driven-side clutch plate 7 in the clutch housing 2. Therefore, in addition to the axial direction of the device, it is possible to increase the clutch capacity while avoiding an increase in size in the direction orthogonal to the axial direction of the device, and it is possible to effectively utilize the space on the inner diameter side in the clutch housing 2.

[0059] Further, according to the present embodiment, when the weight member 10 is at the outer diameter side position, the driving-side clutch plate 6 and the driven-side clutch plate 7 are pressed against each other, and at the same time, the auxiliary clutch plate 17 is pressed against each other so that the driving force of the engine E can be transmitted to the wheels (drive wheels T). At the same time, when the weight member 10 is at the inner diameter side position, the pressing force between the driving-side clutch plate 6 and the driven-side clutch plate 7 is released, and at the same time, the pressing force of the auxiliary clutch plate 17 is released so that the transmission of the driving force of the engine E to the wheels (drive wheels T) can be blocked. Since it has the centrifugal clutch means 9, by the centrifugal clutch means 9, in addition to the pressing or release of the pressing force of the driving-side clutch plate 6 and the driven-side clutch plate 7, the pressing or release of the pressing force of the auxiliary clutch plate 17 can be performed.

[0060] Furthermore, when the weight member 10 is at the outer diameter side position, one of the pressing member 12 and the holding member 11 presses the driving-side clutch plate 7 and the driven-side clutch plate 12 against each other, and the other of the pressing member 12 and the holding member 11 presses the auxiliary clutch plate 17 against each other. Therefore, by the pressing member 12 and the holding member 11 constituting the centrifugal clutch means 9, in addition to the pressing or release of the pressing force of the driving-side clutch plate 6 and the driven-side clutch plate 7, the pressing or release of the pressing force of the auxiliary clutch plate 17 can be performed.

[0061] However, according to the power transmission device K according to the present embodiment, the through hole 10a of the weight member 10 in the centrifugal clutch means 9 is formed in a tapered shape from one opening 10aa to the other opening 10ab, and the first spherical member 14 is prevented from coming off at the outer peripheral edge of the smaller-diameter opening among the one opening 10aa and the other opening 10ab. Therefore, the first spherical member 14 can be simply and accurately attached to the weight member 10, and the manufacturing cost can be reduced.

[0062] Further, the first spherical member 14 and the second spherical member 15 are spherical members having different diameters corresponding to the inner diameter of the through hole 10a, and are configured to be rollable while being in contact with the inner peripheral surface of the through hole 10a. Therefore, the first spherical member 14 and the second spherical member 15 can be stably rolled when the weight member 10 moves, and smooth movement can be achieved. Furthermore, since the second spherical member 15 according to the present embodiment is prevented from coming off at the rolling surface of the holding member 11 or the pressing member 12, it is possible to easily prevent the first spherical member 14 and the second spherical member 15 from coming off by assembling the holding member 11 and the pressing member 12.

[0063] Furthermore, since the rolling surface of the holding member 11 or the pressing member 12 has a groove shape (11b, 12b) along the moving direction of the weight member 10, it is possible to more smoothly move the weight member 10 while surely preventing the second spherical member 15 from coming off on the large-diameter opening side and the first spherical member 14 from coming off on the small-diameter opening side, respectively.

[0064] In addition, a plurality of weight members 10 according to the present embodiment are respectively accommodated in the accommodating portions 11a formed in the circumferential direction of the holding member 11 and are movable in the radial direction. The biasing members 16 are arranged in plural in the circumferential direction between the inner peripheral wall surface 11aa of the accommodating portion 11a and the weight member 10 to bias the weight member 10 from the outer diameter side position toward the inner diameter side position. Therefore, the weight member 10 can be accurately biased from the outer diameter side position toward the inner diameter side position, and the weight member 10 can be stably moved according to the centrifugal force.

[0065] In addition, since the weight member 10 according to the present embodiment is formed with an insertion portion 10b through which the urging member 16 can be inserted while opening the surface facing the holding member 11, the urging member 16 can be easily assembled to the weight member 10. Further, in the weight member 10 according to the present embodiment, a groove 10c is formed in the direction from the inner diameter side position to the outer diameter side position, and the holding member 11 (specifically, the support member 13 fixed and integrated with the holding member 11) is formed with a holding portion 13a that holds the weight member 10 in conformity with the groove 10c, so that the weight member 10 can be stably moved.

[0066] Furthermore, the centrifugal clutch means 9 according to the present embodiment includes a first spherical member 14 that protrudes partially from one opening 10aa of the through hole 10a formed in the weight member 10 and is in contact with and rollable on the rolling surface (groove shape 11b) of the holding member 11, and a second spherical member 15 that protrudes partially from the other opening 10ab of the through hole 10a formed in the weight member 10 and is in contact with and rollable on the rolling surface (groove shape 12b) of the pressing member 12. Therefore, the weight member 10 can be moved more stably.

[0067] In particular, the holding member 11 or the pressing member 12 has a groove shape (11b, 12b) along the moving direction of the weight member 10, and the groove shape (11b, 12b) serves as the rolling surface of the first spherical member 14 or the second spherical member 15. Therefore, the weight member 10 can be moved more smoothly. Further, a plurality of the first spherical members 14 and the second spherical members 15 according to the present embodiment are respectively formed across the circumferential direction (width direction of the weight member 10) of the holding member 11, so that the weight member 10 can be moved more stably.

[0068] As described above, although the present embodiment has been explained, the present invention is not limited to these. For example, as shown in FIG. 26, the auxiliary clutch plate 17 may be composed of a plurality of clutch plates. In this case, in addition to the auxiliary clutch plate 17 connected to the output shaft 3, a first auxiliary clutch plate 17c and a second auxiliary clutch plate 17d are provided to form a multi-plate clutch. When the weight member 10 of the centrifugal clutch means 9 moves to the outer diameter side position and the holding member 11 moves, the second clutch plate 17d is pressed by the pressing surface 11c of the holding member 11, and the auxiliary clutch plate 17, the first auxiliary clutch plate 17c, and the second auxiliary clutch plate 17d are brought into pressure contact with each other, enabling the driving force of the engine E to be transmitted to the wheels (driving wheels T). In this way, if the auxiliary clutch plate 17 is composed of a plurality of clutch plates, the clutch capacity of the auxiliary clutch plate 17 (the multi-plate clutch including the first auxiliary clutch plate 17c and the second auxiliary clutch plate 17d) can be arbitrarily increased.

[0069] Also, as shown in FIG. 27, the auxiliary clutch plate 17 may be composed of a plurality of clutch plates (a multi-plate clutch including the first auxiliary clutch plate 17c and the second auxiliary clutch plate 17d) and may overlap with the laminated portion of the driving-side clutch plate 6 and the driven-side clutch plate 7 in the axial direction X of the clutch housing 2. In this way, by arranging the laminated portion of the driving-side clutch plate 6 and the driven-side clutch plate 7 and the auxiliary clutch plate 17 to overlap in the axial direction X of the clutch housing 2, it is possible to reliably avoid an increase in the size of the apparatus in the axial direction X.

[0070] Furthermore, as shown in FIG. 28, the auxiliary clutch plate 17 is composed of a plurality of clutch plates and has an interlocking member 18 instead of the centrifugal clutch means; as shown in FIG. 29, the auxiliary clutch plate 17 is composed of a plurality of clutch plates and overlaps with the laminated portion of the driving-side clutch plate 6 and the driven-side clutch plate 7 and has an interlocking member 18 instead of the centrifugal clutch means; and as shown in FIG. 30, the auxiliary clutch plate 17 is composed of a plurality of clutch plates, has an interlocking member 18 instead of the centrifugal clutch means, and may have a pressing assist cam and a back torque limiter cam. Note that the interlocking member 18 moves toward the auxiliary clutch plate 17 by the pressing force when the pressing member 5 operates and the driving-side clutch plate 6 and the driven-side clutch plate 7 are pressed into contact with each other, and presses the auxiliary clutch plate 17 into contact.

[0071] However, in the present embodiment, the second spherical member 15 is retained by the rolling surface (groove shape 11a) of the holding member 11 (or the pressing member 12), but may be retained by other retaining means and methods such as caulking. Further, in the present embodiment, in a state where the first clutch member 4a, the second clutch member 4b, and the pressing member 5 are assembled (a state where there is no transmission torque from the input gear 1 (input member) to the output shaft 3 (output member)), the contact surface 4ad and the contact surface 5e are in contact with each other, but they may not have these contact surfaces 4ad and 5e and may be in a separated state. Note that the power transmission device of the present invention can be applied to various multi-plate clutch type power transmission devices such as motorcycles, automobiles, three- or four-wheel buggies, or general-purpose machines.

Industrial Applicability

[0072] An auxiliary clutch plate with a diameter different from that of the driving-side clutch plate and the driven-side clutch plate is disposed in the clutch housing. When the driving-side clutch plate and the driven-side clutch plate are pressed together, the auxiliary clutch plate is pressed to make the driving force of the engine transmissible to the wheels, and when the pressing force between the driving-side clutch plate and the driven-side clutch plate is released, the pressing force of the auxiliary clutch plate is released to block the transmission of the driving force of the engine to the wheels. Such a power transmission device can also be applied to those with different external shapes or those with additional other functions, etc.

Explanation of Signs

[0073] 1 Input gear (input member) 2 Clutch housing 2a Notch 3 Output shaft (output member) 4a First clutch member 4aa Gradient surface (cam for pressing assist) 4ab Gradient surface (cam for back torque limiter) 4ac Boss part 4ad Contact surface 4b Second clutch member 4ba Spline fitting part 4bb Flange part 5 Pressure member 5a Gradient surface (cam for pressing assist) 5b Gradient surface (cam for back torque limiter) 5c Flange part 5d Insertion hole 5e Contact surface 6 Driving-side clutch plate 7 Driven-side clutch plate 8 Fixing member 9 Centrifugal clutch means 10 Weight member 10a Through hole 10b Insertion part 10aa One opening 10ab The other opening 10ba End wall surface 10c Groove 11 Holding member 11a housing part 11aa inner peripheral wall surface 11b groove shape 11c pressing surface 12 crimping member 12a gradient groove 12b groove shape 12c pressing surface 13 supporting member 13a holding part 14 first spherical member 15 second spherical member 16 biasing member 17 auxiliary clutch plate 17a central opening 17b pressed surface 17c first auxiliary clutch plate 17d second auxiliary clutch plate 18 interlocking member S clutch spring

Claims

1. A clutch member housed in a clutch housing that rotates together with an input member rotated by the driving force of an engine of a vehicle and to which a plurality of driving clutch plates are attached, the clutch member being connected to an output member capable of rotating a wheel of the vehicle, an operating position in which the driving clutch plate and a driven clutch plate arranged alternately with the driving clutch plate are pressed against each other to transmit the driving force of the engine to the wheel, and a non-operating position in which the pressing force between the driving clutch plate and the driven clutch plate is released to block the transmission of the driving force of the engine to the wheel, a pressure member movable between the two positions, a weight member movable from an inner diameter side position to an outer diameter side position by centrifugal force accompanying the rotation of the clutch housing, and a pressure contact member provided in contact with the weight member and moving in a direction to press the driving clutch plate and the driven clutch plate when the weight member moves from the inner diameter side position to the outer diameter side position, and having centrifugal clutch means for pressing the driving clutch plate and the driven clutch plate against each other to transmit the driving force of the engine to the wheel when the weight member is in the outer diameter side position and for releasing the pressing force between the driving clutch plate and the driven clutch plate to block the transmission of the driving force of the engine to the wheel when the weight member is in the inner diameter side position, wherein the pressure contact member, has an annular main body portion, a plurality of convex portions protruding in the axial direction of the output member from the main body portion so as to approach the weight member from the inner diameter side to the outer diameter side, contacting the weight member, and arranged in the circumferential direction of the main body portion, and a plurality of protrusion portions protruding radially outward from the outer peripheral edge of the main body portion and attached to the clutch housing, the pressure contact member is configured to move in the axial direction to press the driving clutch plate and the driven clutch plate when the weight member moves from the inner diameter side position to the outer diameter side position along the convex portions, when viewed in the axial direction of the output member, a part of a plurality of straight lines passing through the center of the main body portion and the circumferential center of the protrusion portion overlaps the convex portion, and the other part of the plurality of straight lines does not overlap the convex portion, a power transmission device.

2. The main body portion is formed between the adjacent convex portions and includes a plane on which the protrusion is located on the outer side in the radial direction. When viewed in the axial direction of the output member, the circumferential length of the portion on the outer side in the radial direction of the plane is longer than the circumferential length of the portion on the inner side in the radial direction of the plane. The power transmission device according to claim 1. **Claim 3** The circumferential length of the plane gradually increases from the inner side in the radial direction toward the outer side in the radial direction. The power transmission device according to claim 2. **Claim 4** The main body portion includes a plane formed between the adjacent convex portions. The plane includes a first plane and a second plane. When viewed in the axial direction of the output member, the circumferential length of the portion on the outer side in the radial direction of the second plane is longer than the circumferential length of the portion on the outer side in the radial direction of the first plane. The power transmission device according to claim 1. **Claim 5** The circumferential length of the portion on the inner side in the radial direction of the first plane is longer than the circumferential length of the portion on the inner side in the radial direction of the second plane. The power transmission device according to claim 4.

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