Power transmission

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 equipped 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 that can approach or separate 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, a centrifugal clutch means including a weight member that can move from the inner diameter side position to the outer diameter side position of the groove portion by centrifugal force accompanying the rotation of the clutch housing is proposed. According to such a conventional power transmission device, when the clutch housing rotates as the engine drives, 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 the above-mentioned conventional power transmission device, it may be necessary to increase the number of drive-side clutch plates and driven-side clutch plates in order to realize the clutch capacity required for the multi-plate clutch. In such a case, if the drive-side clutch plates and driven-side clutch plates are simply increased in the stacking direction of the multi-plate clutch, the device becomes larger in the axial direction, and there is a risk that it may exceed the available installation space for the vehicle. Note that this problem is not limited to those equipped with weight members, but may occur in all multi-plate clutch type power transmission devices that have drive-side clutch plates and driven-side clutch plates.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a power transmission device that can increase the clutch capacity while avoiding an increase in the axial size of the device. [Means for solving the problem]

[0007] The invention described in claim 1 is a clutch member that rotates together with an input member that rotates by the driving force of a vehicle engine, and is accommodated in a clutch housing to which a plurality of driving side clutch plates are attached, the clutch member having an outer peripheral surface formed with a spline fitting portion into which inner peripheral edges of a plurality of driven side clutch plates that are formed alternately with the driving side clutch plates are fitted, the clutch member being connected to an output member that can rotate wheels of a vehicle, the clutch member having an operating position in which the driving side clutch plates and the driven side clutch plates are pressed together to make it possible to transmit the driving force of the engine to the wheels, and a disengagement position in which the pressing force between the driving side clutch plates and the driven side clutch plates is released to make it possible to transmit the driving force of the engine to the wheels. A power transmission device comprising: a pressure member movable between a neutral position and a non-operating position where the transmission of the driving force of the engine to the wheels can be interrupted; and 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 together, the auxiliary clutch plate is pressed together to enable the transmission of the driving force of the engine 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 interrupt the transmission of the driving force of the engine to the wheels.

[0008] The invention described in claim 2 is characterized in that, in the power transmission device described in claim 1, it comprises a weight member that is movable from an inner diameter side position to an outer diameter side position by centrifugal force accompanying rotation of the clutch housing, and when the weight member is in the outer diameter side position, it presses the driving side clutch plate and the driven side clutch plate and also presses the auxiliary clutch plate so that the driving force of the engine can be transmitted to the wheels, and when the weight member is in the inner diameter side position, it releases the pressing force between the driving side clutch plate and the driven side clutch plate and releases the pressing force of the auxiliary clutch plate so as to interrupt the transmission of the driving force of the engine to the wheels.

[0009] The invention described in claim 3 is characterized in that, in the power transmission device described in claim 2, at least a portion of the centrifugal clutch means is positioned between the auxiliary clutch plate and the driving side clutch plate and the driven side clutch plate. The invention of claim 4 is characterized in that, in the power transmission device of claim 2 or 3, the centrifugal clutch means is configured including a retaining member that holds the weight member movably between the inner diameter side position and the outer diameter side position, a pressing member that moves in the stacking direction of the driving side clutch plate and the driven side clutch plate as the weight member moves from the inner diameter side position to the outer diameter side position, thereby pressing the driving side clutch plate and the driven side clutch plate together, and a biasing member that biases the weight member from the outer diameter side position toward the inner diameter side position, and when the weight member is in the outer diameter side position, one of the pressing member and the retaining member presses the driving side clutch plate and the driven side clutch plate together, and the other of the pressing member and the retaining member presses the auxiliary clutch plate together.

[0010] The invention described in claim 5 is characterized in that, in the power transmission device described in any one of claims 1 to 4, the stacked portions of the driving side clutch plate and the driven side clutch plate and the auxiliary clutch plate are arranged 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 made up of a plurality of clutch plates. The invention described in claim 7 relates to a clutch member that rotates together with an input member that rotates by the driving force of a vehicle engine and is accommodated in a clutch housing to which a plurality of driving side clutch plates are attached, the clutch member being attached to a plurality of driven side clutch plates that are arranged alternately with the driving side clutch plates and connected to an output member that can rotate wheels of a vehicle; a pressure member that is movable between an operating position in which the driving side clutch plates and the driven side clutch plates are brought into pressure contact with each other to make it possible to transmit the driving force of the engine to the wheels and a non-operating position in which the pressure contact force between the driving side clutch plates and the driven side clutch plates is released to interrupt the transmission of the driving force of the engine to the wheels; an auxiliary clutch plate disposed on the output member; and A power transmission device having a weight member that can be moved from an inner diameter side position to an outer diameter side position by the centrifugal force accompanying the rotation of a housing, and a centrifugal clutch means provided between the driving side clutch plate, the driven side clutch plate, and the auxiliary clutch plate, wherein when the weight member is in the outer diameter side position, it presses the driving side clutch plate and the driven side clutch plate together and presses the auxiliary clutch plate so that the driving force of the engine can be transmitted to the wheels, and when the weight member is in the inner diameter side position, it releases the pressing force between the driving side clutch plate and the driven side clutch plate and releases the pressing force of the auxiliary clutch plate so that the transmission of the driving force of the engine to the wheels can be interrupted. The invention described in claim 8 is characterized in that, in the power transmission device described in claim 7, a spline fitting portion is formed on the outer surface of the clutch member into which the inner peripheral edge of the driven side clutch plate fits, 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 of claim 9 is the power transmission device of claim 7 or 8, wherein the auxiliary clutch plate overlaps with at least a portion of the centrifugal clutch means when viewed in the radial direction of the output member. Effect 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 arranged in the clutch housing, and when the driving side clutch plate and the driven side clutch plate are pressed together, the auxiliary clutch plate is pressed together to enable the driving force of the engine to be transmitted 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 cut off the transmission of the driving force of the engine to the wheels, so that it is possible to increase the clutch capacity while avoiding an increase in the axial size of the device.

[0013] According to the invention of claim 2, when the weight member is in the outer diameter side position, the centrifugal clutch means presses the driving side clutch plate and the driven side clutch plate together, and at the same time presses the auxiliary clutch plate together, making it possible to transmit the driving force of the engine to the wheels, and when the weight member is in the inner diameter side position, the centrifugal clutch means releases the pressing force between the driving side clutch plate and the driven side clutch plate, and at the same time releases the pressing force of the auxiliary clutch plate, thereby cutting off the transmission of the driving force of the engine to the wheels.Therefore, in addition to pressing or releasing the pressing force of the driving side clutch plate and the driven side clutch plate, the centrifugal clutch means can press or release the pressing force of the auxiliary clutch plate.

[0014] According to the invention of claim 4, when the weight member is in the outer diameter side position, one of the pressing member and the retaining member presses the driving side clutch plate and the driven side clutch plate, and the other of the pressing member and the retaining member presses the auxiliary clutch plate. Therefore, the pressing member and the retaining member that constitute the centrifugal clutch means can press the driving side clutch plate and the driven side clutch plate or release the pressing force, as well as press the auxiliary clutch plate or release the pressing force.

[0015] According to the invention of claim 5, the stacked portions of the driving side clutch plate and the driven side clutch plate and the auxiliary clutch plate are arranged offset from each other in the axial direction of the clutch housing, thereby reliably avoiding an increase in the axial size of the device.

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

[0017] [Figure 1] 1 is an external view showing a power transmission device according to an embodiment of the present invention; [Diagram 2] Cross-sectional view of line II-II in Figure 1 [Diagram 3] Cross-sectional view of line III-III in Figure 1 [Figure 4] FIG. 4 is a perspective view showing a clutch housing in the power transmission device; [Diagram 5] FIG. 3 is a three-view diagram showing a first clutch member in the power transmission device. [Figure 6] FIG. [Figure 7] FIG. 3 is a three-view diagram showing a second clutch member in the power transmission device. [Figure 8] FIG. 4 is a perspective view showing the second clutch member of the same [Figure 9] A three-dimensional view showing a pressure member in the power transmission device. [Figure 10] FIG. [Figure 11] FIG. 4 is a vertical cross-sectional view showing a centrifugal clutch means in the power transmission device. [Figure 12] FIG. 4 is a partially cutaway perspective view showing the centrifugal clutch means. [Figure 13] 3A to 3C are three views showing a holding member constituting the centrifugal clutch means; [Figure 14] 3A to 3C are three views showing a support member constituting the centrifugal clutch means; [Figure 15] 3A to 3C are three views showing a pressing member constituting the centrifugal clutch means; [Figure 16] 4A to 4C are views showing a weight member constituting the centrifugal clutch means; [Figure 17] Cross-sectional view of line XVII-XVII in FIG. [Figure 18] FIG. 11 is a plan view showing a state in which the weight member of the centrifugal clutch means is in an inner diameter side position. [Figure 19] FIG. 11 is a plan view showing a state in which the weight member of the centrifugal clutch means is in an outer diameter side position. [Figure 20] FIG. 1 is a schematic diagram for explaining (a) the function of a pressure-contact assist cam and (b) the function of a back torque limiter cam in the power transmission device. [Figure 21] FIG. 1 is a schematic diagram showing a vehicle to which the power transmission device is applied; [Figure 22] FIG. 4 is a cross-sectional view showing a state in which the weight member in the power transmission device is in an inner diameter side position. [Figure 23] FIG. 4 is a cross-sectional view showing a state in which the weight member in the power transmission device is in an intermediate position between an inner diameter side position and an outer diameter side position. [Figure 24] FIG. 4 is a cross-sectional view showing a state in which the weight member in the power transmission device is in an outer diameter side position. [Diagram 25] FIG. 4 is a cross-sectional view showing a state in which the weight member is in an outer diameter side position and the pressure member is in a non-operating position in the power transmission device; [Figure 26] FIG. 11 is a vertical cross-sectional view showing a power transmission device according to another embodiment of the present invention (wherein the auxiliary clutch plate is made up of a plurality of clutch plates). [Figure 27] FIG. 11 is a vertical cross-sectional view showing a power transmission device according to another embodiment of the present invention (wherein the auxiliary clutch plate is made up of a plurality of clutch plates and overlaps with the stacked portions of the driving clutch plate and the driven clutch plate). [Figure 28] FIG. 11 is a vertical cross-sectional view showing a power transmission device according to another embodiment of the present invention (wherein the auxiliary clutch plate is made up of a plurality of clutch plates and does not have a centrifugal clutch means). [Figure 29] FIG. 1 is a longitudinal sectional view showing a power transmission device according to another embodiment of the present invention (wherein the auxiliary clutch plate is made up of a plurality of clutch plates and overlaps with the stacked portions of the driving side clutch plate and the driven side clutch plate, and does not have a centrifugal clutch means). [Diagram 30] FIG. 1 is a vertical cross-sectional view showing a power transmission device according to another embodiment of the present invention (wherein the auxiliary clutch plate is made up of a plurality of clutch plates, the device does not have a centrifugal clutch means, and the device has a pressure-contact assist cam and a back torque limiter cam). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The power transmission device K of this embodiment, as shown in FIG. 21, is disposed in a vehicle for transmitting or blocking the driving force of an engine E to driving wheels T via a transmission M, and as shown in FIGS. 1 to 17, is configured to include a clutch housing 2 having an input gear 1 (input member) formed therein that rotates by the driving force of the vehicle's engine E, an output shaft 3 (output member) connected to the transmission M, clutch members (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, a centrifugal clutch means 9 having a weight member 10, and an auxiliary clutch plate 17.

[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 rivets or the like. The clutch housing 2 is made of a cylindrical member that is open on the right end side in Figures 2 and 3 and is configured to be connected to the input gear 1 so that it can rotate together with the input gear 1 by the driving force of the engine E.

[0020] 4, the clutch housing 2 has a plurality of notches 2a formed in the circumferential direction, and a plurality of driving side clutch plates 6 are attached by fitting into these notches 2a. Each of the driving side clutch plates 6 is made of a plate material formed in a substantially annular shape, and is configured to rotate together with the rotation of the clutch housing 2 and to be able to slide in the axial direction (the left-right direction in FIGS. 2 and 3).

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

[0022] The first clutch member 4a is configured such that the output shaft 3 is inserted into an insertion hole (see Figs. 5 and 6) formed in the center thereof, and the gears formed therein mesh with each other to couple in the rotational direction. As shown in Figs. 5 and 6, the first clutch member 4a is formed with a sloped surface 4aa constituting a pressure contact assist cam and a sloped surface 4ab constituting a back torque limiter cam. In addition, the reference symbol 4ac in the figures indicates a boss portion in which a through hole for a bolt B for coupling the first clutch member 4a to the fixed member 8 is formed.

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

[0024] As shown in Figures 9 and 10, the pressure member 5 is made of a disk-shaped member with a flange portion 5c formed around its periphery, and is movable between an operating position where the driving side clutch plate 6 and the driven side clutch plate 7 are pressed together to enable the transmission of the driving force of the engine E to the wheels, and a non-operating position where the pressing force between the driving side clutch plate 6 and the driven side clutch plate 7 is released to interrupt the transmission of the driving force of the engine E to the wheels.

[0025] More specifically, the spline fitting portion 4ba formed on the second clutch member 4b is configured with a concave-convex shape formed integrally around almost the entire circumference of the outer circumferential side surface of the second clutch member 4b, as shown in Figures 7 and 8, and the driven-side clutch plate 7 fits into the concave groove that constitutes the spline fitting portion 4ba, thereby allowing axial movement of the driven-side clutch plate 7 relative to the second clutch member 4b while restricting movement in the rotational direction, so that the driven-side clutch plate 7 can rotate together with the second clutch member 4b.

[0026] The driven-side clutch plates 7 and the driving-side clutch plates 6 are alternately stacked, and adjacent clutch plates 6, 7 can be pressed or released from the pressing force. That is, both clutch plates 6, 7 are allowed to slide in the axial direction of the second clutch member 4b, and when the clutch plates (6a, 6b, 7a, 7b) are pressed and the clutch is turned on, 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, and when the pressing force of the clutch plates (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, when the driving side clutch plate 6 and the driven side 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 driving wheels (transmission M) via the output shaft 3 (output member), and when the pressing contact between the driving side clutch plate 6 and the driven side clutch plate 7 is released, the transmission of the rotational force (driving force of the engine E) input to the clutch housing 2 to the output shaft 3 (output member) can be blocked.

[0028] 9 and 10, the pressure member 5 has a plurality of fitting holes 5d (three in this embodiment) formed in the circumferential direction, and a clutch spring S is fitted into each fitting hole 5d. As shown in Fig. 2, the clutch spring S is housed in the fitting hole 5d and one end abuts against the fixed member 8, and is biased in a direction to press the driving side clutch plate 6 and the driven side clutch plate 7 together. By operating a clutch operating means (not shown), the driving side clutch plate 6 and the driven side clutch plate 7 can be pressed together or released from the pressed contact.

[0029] 5, 6, 9 and 10, in this embodiment, the first clutch member 4a is formed with inclined surfaces 4aa and 4ab, and the pressure member 5 is formed with inclined surfaces 5a and 5b facing the inclined surfaces 4aa and 4ab. That is, the inclined surfaces 4aa and 5a come into contact with each other to form a pressure contact assist cam, and the inclined surfaces 4ab and 5b come into contact with each other to form a back torque limiter cam.

[0030] Then, when the rotational speed of the engine E 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 in the outer diameter side position), as shown in Fig. 20(a), a rotational force in the direction a is applied to the pressure member 5, and a force in the direction c in the figure is generated in the pressure member 5 by the action of the pressure contact assist cam. As a result, the pressure member 5 moves in a direction (left side in Figs. 2 and 3) in which the flange portion 5c comes closer to the flange portion 4bb of the second clutch member 4b, thereby increasing the pressure contact force between the driving side clutch plate 6 and the driven side clutch plate 7.

[0031] On the other hand, when the rotation of the output shaft 3 exceeds the rotation speed of the input gear 1 and the clutch housing 2 and back torque is generated, as shown in Fig. 20(b), a rotational force in the direction b is applied to the clutch member 4, so that the back torque limiter cam acts to move the pressure member 5 in the direction d in the figure, releasing the pressure contact force between the driving side clutch plate 6 and the driven side clutch plate 7. This makes it possible to avoid malfunctions of the power transmission device K and the power source (engine E side) due to back torque.

[0032] As shown in Figures 11 to 19, the centrifugal clutch means 9 is equipped with a weight member 10 that is movable from an inner diameter side position (see Figure 18) to an outer diameter side position (see Figure 19) by the centrifugal force accompanying the rotation of the clutch housing 2. When the weight member 10 is in the outer diameter side position, it presses the driving side clutch plate 6 and the driven side clutch plate 7 together, making it possible to transmit the driving force of the engine E to the wheels (drive wheels T), and when the weight member 10 is in the inner diameter side position, it releases the pressing force between the driving side clutch plate 6 and the driven side clutch plate 7, thereby cutting off the transmission of the driving force of the engine E to the wheels (drive wheels T).

[0033] Specifically, the centrifugal clutch means 9 is configured to include a weight member 10 formed of a bridge-shaped member, a retaining 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 formed of a coil spring. The retaining member 11 and the pressure contact member 12 have a plurality of protrusions formed in the circumferential direction, and are attached by fitting into the notch 2a of the clutch housing 2, similar to the driving side clutch plate 6. As a result, the retaining member 11 and the pressure contact member 12 are each movable in the axial direction of the clutch housing 2, and are engaged with each other in the rotational direction to be rotatable together with the clutch housing 2.

[0034] As shown in Fig. 16, the weight member 10 is made of a piece-shaped member having one surface X and the other surface Y, and as shown in Fig. 16 and Fig. 17, it is configured to have a through hole 10a formed penetrating 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 the one surface X. As shown in Figs. 18 and 19, the weight member 10 is accommodated in an accommodating portion 11a of a holding member 11, and is held at an inner diameter side position (see Fig. 18) when no centrifugal force is applied, and moves outward against the biasing force of a biasing member 16 when centrifugal force is applied, to reach an outer diameter side position (see Fig. 19).

[0035] The holding member 11 holds the weight member 10 movably between an inner diameter side position and an outer diameter side position, and is made of an annular member, as shown in Fig. 13, and is configured with a plurality of accommodating portions 11a formed in the circumferential direction and accommodating the weight member 10, a groove shape 11b formed in the accommodating portion 11a, and a pressing surface 11c. Each accommodating portion 11a has a concave shape that matches the shape and movement range of the weight member 10, and is configured so that one end of the biasing member 16 can abut against its inner peripheral wall surface 11aa.

[0036] In addition, a support member 13 is fixed to the surface of the holding member 11 on which the accommodation portion 11a is formed. As shown in Fig. 14, the support member 13 has a holding portion 13a formed in the radial direction, and the holding portion 13a fits into a groove 10c of the weight member 10, thereby holding the weight member 10 on the holding member 11. That is, the weight member 10 has a groove 10c formed in the center position of one surface X of the weight member 10 in a direction from an inner diameter side position to an outer diameter side position, and the weight member 10 is held movably in the radial direction (from the inner diameter side position to the outer diameter side position) by fitting the holding portion 13a into the groove 10c.

[0037] As the weight member 10 moves from an inner diameter side position to an outer diameter side position, the pressing member 12 moves in the stacking direction of the driving side clutch plates 6 and the driven side clutch plates 7 (to the right in Figs. 2 and 3), thereby pressing the driving side clutch plates 6 and the driven side clutch plates 7 together. Specifically, as shown in Fig. 15, the pressing member 12 is made of an annular member and is configured to have a plurality of gradient grooves 12a formed in the circumferential direction, groove shapes 12b formed at the positions where the gradient grooves 12a are formed, and a pressing surface 12c.

[0038] The gradient grooves 12a are formed at positions corresponding to the weight members 10, and have an upward gradient from the inside to the outside. As a result, when the clutch housing 2 is stopped, the weight members 10 are 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 members 10, causing them to move along the upward gradient grooves 12a, thereby moving the pressing member 12 in a direction away from the holding member 11 (i.e., in a direction in which the driving-side clutch plate 6 and the driven-side clutch plate 7 are pressed against each other).

[0039] When the retaining member 11 and the pressure contact member 12 are assembled with the weight member 10 interposed therebetween, as shown in Figures 11 and 12, the sloped grooves 12a are positioned corresponding to each weight member 10, and the centrifugal force causes the weight member 10 to move along the sloped grooves 12a from the inner diameter side position to the outer diameter side position, causing the pressure contact member 12 to move in the direction of the arrow in Figure 11 (to the right in the figure), and the pressing surface 12c formed on the pressure contact member 12 presses against the driving side clutch plate 6 and the driven side clutch plate 7 to bring them into a pressed state, and the retaining member 11 moves in the opposite direction to the arrow in Figure 11 (to the left in the figure) due to the reaction force, and the pressing surface 11c formed on the retaining member 11 presses against the auxiliary clutch plate 17.

[0040] 18 and 19, the weight members 10 according to this embodiment are accommodated in a plurality of accommodation sections 11a formed around the circumferential direction of the holding member 11 and are movable in the radial direction, and a plurality of biasing members 16 (two each in this embodiment) are arranged in the circumferential direction between an inner peripheral wall surface 11aa (see FIG. 13) of the accommodation sections 11a and the weight member 10 to bias the weight member 10 from an outer diameter side position toward an inner diameter side position. Here, the inner peripheral wall surface 11aa of the accommodation sections 11a is a flat surface that abuts against one end of the biasing member 16, allowing the biasing member 16 to be attached in a stable state.

[0041] Moreover, 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 and attached, with the surface facing the holding member 11 (the other surface Y in FIG. 17) open. Then, by accommodating the weight member 10 with the biasing member 16 inserted into the insertion portion 10b in the accommodating portion 11a of the holding member 11, the biasing member 16 is attached between the inner peripheral wall surface 11aa of the accommodating portion 11a and the weight member 10. The biasing member 16 is disposed such that one end abuts against the inner peripheral wall surface 11aa and the other end abuts against the end wall surface 10ba of the insertion portion 10b, and is capable of biasing the weight member 10 from the outer diameter side position toward the inner diameter side position.

[0042] The first spherical member 14 is made of a steel ball attached to the weight member 10, and as shown in Figures 16 and 17, it protrudes partially from one opening 10aa (a small-diameter opening on one surface X) of a through hole 10a formed in the weight member 10, making it possible for it to roll in contact with the rolling surface of the pressure contact member 12. The second spherical member 15 is made of a steel ball attached to the weight member 10, and as shown in Figures 16 and 17, it protrudes partially from the other opening 10ab (a large-diameter opening on the other surface Y) of a through hole 10a formed in the weight member 10, making it possible for it to roll in contact with the rolling surface of the holding member 11.

[0043] As shown in Fig. 17, the through hole 10a according to this embodiment is tapered so that the diameter increases continuously from one opening 10aa (a small-diameter opening on one surface X side) to the other opening 10ab (a large-diameter opening on the other surface Y side), and the first spherical member 14 is retained at the outer periphery of the smaller-diameter opening (the opening 10aa on the one surface X side in this embodiment) between 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 of different diameters (the second spherical member 15 is a member with a larger diameter than the first spherical member 14) according to the inner diameter of the through hole 10a, and the first spherical member 14 with a small diameter is retained at the opening edge on the small-diameter side of the through hole 10a and can roll in contact with the inner periphery of the through hole 10a.

[0044] On the other hand, the second spherical member 15 is prevented from coming off by the rolling surface of the holding member 11, as shown in Figs. 11 and 12. As a result, the small-diameter first spherical member 14 is prevented from coming off by the opening edge on the small-diameter side of the through hole 10a, and the large-diameter second spherical member 15 is prevented from coming off by the rolling surface of the holding member 11 while part of it protrudes 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 pressing member 12. In this case, the small-diameter first spherical member 14 is prevented from coming off by the opening edge on the small-diameter side of the through hole 10a, and the large-diameter second spherical member 15 is prevented from coming off by the rolling surface of the pressing member 12 while part of it protrudes from the opening on the large-diameter side of the through hole 10a.

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

[0046] Furthermore, as shown in Figures 16, 18 and 19, the first spherical members 14 and the second spherical members 15 in this embodiment are each formed in multiple numbers (two first spherical members 14 and two second spherical members 15 in this embodiment) along the circumferential direction of the retaining member 11 (the width direction of the weight member 10), so that as the weight member 10 moves, the first spherical members 14 and the second spherical members 15 can each roll within the through hole 10a and move along the groove shapes 11b, 12b.

[0047] The auxiliary clutch plate 17 is disposed within the clutch housing 2 and consists of an annular member having a different diameter than the driving side clutch plate 6 and the driven side clutch plate 7 (in this embodiment, a smaller diameter than the driving side clutch plate 6 and the driven side clutch plate 7). As shown in Figures 2 and 3, the output shaft 3 (output member) is inserted into the central opening 17a to be in a fitted state, and the auxiliary clutch plate 17 has a pressed surface 17b facing the pressing surface 11c of the retaining member 11.

[0048] When the weight member 10 is in the outer diameter side position (i.e., when the driving side clutch plate 6 and the driven side clutch plate 7 are in a pressed state), the auxiliary clutch plate 17 is pressed against the pressing surface 11c formed on the holding member 11, so that the auxiliary clutch plate 17 can transmit the driving force of the engine E to the output shaft 3. When the weight member 10 is in the inner diameter side position (i.e., when the pressing force of the driving side clutch plate 6 and the driven side clutch plate 7 is released), the pressing force by the pressing surface 11c formed on the holding member 11 decreases and the pressing force is released, so that 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 surface 17b to be pressed of the auxiliary clutch plate 17, so that 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, and 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 state of being in contact with each other.

[0051] In this way, in a state where the contact surface 4ad and the contact surface 5e are in contact with each other, 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, so 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) and is pressed against the flange portion 4bb of the second clutch member 4b, pressing the driving side clutch plate 6 and the driven side clutch plate 7 together, and when the pressing force of the flange portion 4bb exceeds the biasing force of the clutch spring S, the second clutch member 4b and the pressure member 5 are moved in the axial direction (rightward in FIGS. 2 and 3) relative 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 from each other. Note that FIG. 25 shows a state in which the weight member 10 is in the outer diameter side position and the pressure member 5 is in the non-operating position (clutch-off state).

[0053] In this manner, when the abutment surface 4ad and the abutment surface 5e are separated from each other, 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 transmitted 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 permitted, and therefore operation of the pressure-assist cam is permitted.

[0054] In other words, according to this embodiment, when the driving 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 driving 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 cut off the transmission of the driving force of the engine E to the wheels (drive wheels T).

[0055] More specifically, in this embodiment, a centrifugal clutch means 9 equipped with a weight member 10 is provided, and when the weight member 10 is in the outer diameter side position, it presses the driving side clutch plate 6 and the driven side clutch plate 7 together, and at the same time presses the auxiliary clutch plate 17 together, making it possible to transmit the driving force of the engine E to the wheels (driving wheels T). When the weight member 10 is in the inner diameter side position, it releases the pressure between the driving side clutch plate 6 and the driven side clutch plate 7, and at the same time releases the pressure of the auxiliary clutch plate 17, thereby cutting off the transmission of the driving force of the engine E to the wheels (driving wheels T).

[0056] Particularly in this embodiment, when the weight member 10 is in the outer diameter side position, the pressing member 12 and the holding member 11 move in directions away from each other, the pressing member 12 presses the driving side clutch plate 6 and the driven side clutch plate 7 together, and the holding member 11 presses the auxiliary clutch plate 17. Note that the centrifugal clutch means 9 may be disposed so that when the weight member 10 is in the outer diameter side position, the pressing member 12 and the holding member 11 move in directions away from each other, the holding member 11 presses the driving side clutch plate 6 and the driven side clutch plate 7 together, and the pressing member 12 presses the auxiliary clutch plate 17 together.

[0057] According to this embodiment, an auxiliary clutch plate 17 having a different diameter than the driving side clutch plate 6 and the driven side clutch plate 7 is arranged in the clutch housing 2, and when the driving 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 (driven wheels T), and when the pressing force between the driving 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 (driven 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 in this embodiment is arranged within the clutch housing 2 on the inner diameter side of the stacked portion (multi-plate clutch portion) of the driving side clutch plate 6 and the driven side clutch plate 7. This makes it possible to increase the clutch capacity while avoiding an increase in size not only in the axial direction of the device but also in the direction perpendicular to the axial direction of the device, and also makes it possible to effectively utilize the space on the inner diameter side within the clutch housing 2.

[0059] Furthermore, according to this embodiment, when the weight member 10 is in the outer diameter side position, the centrifugal clutch means 9 presses the driving side clutch plate 6 and the driven side clutch plate 7 together, and at the same time presses the auxiliary clutch plate 17 together, making it possible to transmit the driving force of the engine E to the wheels (driving wheels T), and when the weight member 10 is in the inner diameter side position, the centrifugal clutch means 9 releases the pressing force between the driving side clutch plate 6 and the driven side clutch plate 7, and at the same time releases the pressing force of the auxiliary clutch plate 17, thereby cutting off the transmission of the driving force of the engine E to the wheels (driving wheels T).Therefore, in addition to pressing or releasing the pressing force of the driving side clutch plate 6 and the driven side clutch plate 7, the centrifugal clutch means 9 can press or release the pressing force of the auxiliary clutch plate 17.

[0060] Furthermore, when the weight member 10 is in the outer diameter side position, one of the pressing member 12 and the retaining member 11 presses the driving side clutch plate 7 and the driven side clutch plate 12 together, and the other of the pressing member 12 and the retaining member 11 presses the auxiliary clutch plate 17. Therefore, the pressing member 12 and the retaining member 11 which constitute the centrifugal clutch means 9 can press the driving side clutch plate 6 and the driven side clutch plate 7 together or release the pressing force, as well as press the auxiliary clutch plate 17 together or release the pressing force.

[0061] However, according to the power transmission device K of this 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 out by the outer peripheral edge portion of the smaller diameter opening of the one opening 10aa and the other opening 10ab. Therefore, the first spherical member 14 can be easily and accurately attached to the weight member 10, and manufacturing costs can be reduced.

[0062] In addition, the first spherical member 14 and the second spherical member 15 are made of spherical members of different diameters corresponding to the inner diameter of the through hole 10a, and are capable of rolling while in contact with the inner circumferential surface of the through hole 10a, so that 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, the second spherical member 15 according to this embodiment is prevented from coming off by the rolling surface of the retaining member 11 or the pressing member 12, so that the first spherical member 14 and the second spherical member 15 can be easily prevented from coming off by assembling the retaining member 11 and the pressing member 12.

[0063] Furthermore, since the rolling surface of the retaining member 11 or the pressure contact member 12 is formed with a groove shape (11b, 12b) along the movement direction of the weight member 10, it is possible to ensure that the second spherical member 15 on the large diameter opening side and the first spherical member 14 on the small diameter opening side are prevented from coming off, while allowing the weight member 10 to move more smoothly.

[0064] In addition, the weight members 10 in this embodiment are accommodated in multiple accommodating sections 11a formed around the circumferential direction of the retaining member 11, and are movable in the radial direction, and the biasing members 16 are arranged in multiple units in the circumferential direction between the inner wall surface 11aa of the accommodating sections 11a and the weight member 10 to bias the weight member 10 from the outer diameter side position toward the inner diameter side position. As a result, the weight member 10 can be biased with high precision from the outer diameter side position toward the inner diameter side position, and the weight member 10 can be stably moved in response to 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, so that 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] Although the present embodiment has been described above, the present invention is not limited thereto. For example, as shown in FIG. 26, the auxiliary clutch plate 17 may be made up 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, and 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 pressed together, so that the driving force of the engine E can be transmitted to the wheels (driving wheels T). In this way, if the auxiliary clutch plate 17 is made up of a plurality of clutch plates, the clutch capacity of the auxiliary clutch plate 17 (multi-plate clutch including the first auxiliary clutch plate 17c and the second auxiliary clutch plate 17d) can be increased arbitrarily.

[0069] 27, the auxiliary clutch plates 17 may be made up of a plurality of clutch plates (a multi-plate clutch including first auxiliary clutch plates 17c and second auxiliary clutch plates 17d) and may overlap with the stacked portions of the driving side clutch plates 6 and the driven side clutch plates 7 in the axial direction X of the clutch housing 2. In this way, by arranging the stacked portions of the driving side clutch plates 6 and the driven side clutch plates 7 and the auxiliary clutch plates 17 so as to overlap in the axial direction X of the clutch housing 2, it is possible to reliably prevent the device from becoming large in size in the axial direction X.

[0070] Furthermore, as shown in Fig. 28, the auxiliary clutch plate 17 may be made up of a plurality of clutch plates and have an interlocking member 18 instead of the centrifugal clutch means, as shown in Fig. 29, the auxiliary clutch plate 17 may be made up of a plurality of clutch plates and overlap the stacked portions of the driving clutch plate 6 and the driven clutch plate 7 and have an interlocking member 18 instead of the centrifugal clutch means, and as shown in Fig. 30, the auxiliary clutch plate 17 may be made up of a plurality of clutch plates and have an interlocking member 18 instead of the centrifugal clutch means, and have a pressure contact assist cam and a back torque limiter cam. When the pressure member 5 operates to press the driving clutch plate 6 and the driven clutch plate 7 together, the interlocking member 18 moves toward the auxiliary clutch plate 17 by the pressure contact force and presses the auxiliary clutch plate 17.

[0071] However, in this embodiment, the second spherical member 15 is prevented from coming off by the rolling surface (groove shape 11a) of the holding member 11 (or the pressing member 12), but may be prevented from coming off by other means and methods such as crimping. Furthermore, in this embodiment, when the first clutch member 4a, the second clutch member 4b, and the pressure member 5 are assembled (when there is no torque transmitted 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 the contact surface 4ad and the contact surface 5e may not be present and may be separated from each other. The power transmission device of the present invention can be applied to various multi-plate clutch type power transmission devices such as automobiles, three-wheeled or four-wheeled buggies, and general-purpose machines in addition to motorcycles. [Industrial Applicability]

[0072] As long as it is a power transmission device in which auxiliary clutch plates of a different diameter from the driving side clutch plates and the driven side clutch plates are arranged in a clutch housing, and when the driving side clutch plates and the driven side clutch plates are pressed together, the auxiliary clutch plates are pressed together to enable the driving force of the engine to be transmitted to the wheels, and when the pressing force between the driving side clutch plates and the driven side clutch plates is released, the pressing force of the auxiliary clutch plates is released to cut off the transmission of the driving force of the engine to the wheels, the device can be applied to devices with different external shapes or devices with added functions. [Explanation of symbols]

[0073] 1 Input gear (input member) 2 Clutch housing 2a notch 3 Output shaft (output member) 4a First clutch member 4aa Slope surface (cam for pressure welding assistance) 4ab slope surface (cam for back torque limiter) 4ac boss part 4ad Contact surface 4b Second clutch member 4ba Spline fitting 4bb flange 5 Pressure member 5a Slope surface (cam for pressure welding assistance) 5b Slope surface (back torque limiter cam) 5c Flange part 5d inset hole 5e Contact surface 6 Drive 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 other opening 10ba end wall 10c groove 11 Retaining member 11a Storage section 11aa Inner wall surface 11b Groove shape 11c Pressing surface 12 Pressure welding member 12a Gradient groove 12b Groove shape 12c Pressing surface 13 Support member 13a Holding part 14 First spherical member 15 Second spherical member 16 Pressurizing member 17 Auxiliary clutch plate 17a central opening 17b Pressed surface 17c First auxiliary clutch plate 17d Second auxiliary clutch plate 18 Interlocking parts S clutch spring

Claims

[Claim 1] a clutch member that rotates together with an input member that rotates by the driving force of a vehicle engine and is accommodated in a clutch housing to which a plurality of driving side clutch plates are attached, the clutch member having a plurality of driven side clutch plates that are alternately formed with the driving side clutch plates attached thereto, and that is connected to an output member that can rotate wheels of the vehicle; a pressure member that is movable between an operating position where the driving side clutch plate and the driven side clutch plate are brought into pressure contact with each other to make it possible to transmit the driving force of the engine to the wheels, and a non-operating position where the pressure contact force between the driving side clutch plate and the driven side clutch plate is released to cut off the transmission of the driving force of the engine to the wheels, The clutch member is a cam portion having a first inclined surface constituting a pressure contact assist cam, a second inclined surface constituting a back torque limiter cam, and a cam top surface located between the first inclined surface and the second inclined surface in a circumferential direction; a boss portion extending from the cam top surface toward the pressure member, the cam top surface has a flat surface that surrounds the entire periphery of the boss portion when viewed in the axial direction of the output member, a power transmission device, when viewed from the axial direction of the output member, the first radial length from the point where a straight line passing through the axis of the output member and the center of the boss portion intersects with the radial outer edge of the cam top surface to the boss portion is longer than the second radial length from the point where the straight line intersects with the radial inner edge of the cam top surface to the boss portion.

Images