Power transmission

Abstract

To provide a power transmission device capable of biasing a weight member from an outer diameter side position toward an inner diameter side position with accuracy, and capable of stably moving the weight member according to centrifugal force.SOLUTION: Centrifugal clutch means 9 is configured to comprise a holding member 11, a pressure-contact member 12, and biasing members 16 that bias a weight member 10 from an outer diameter side position toward an inner diameter side position. The weight members 10 are accommodated in a plurality of accommodation parts 11a formed in a circumferential direction of the holding member 11, and are movable in a radial direction. The biasing members 16 are arranged in the circumferential direction between an inner wall surface 11aa of the accommodation part 11a and the weight member 10, and bias the weight member 10 from the outer diameter side position toward the inner diameter side position.SELECTED DRAWING: Figure 17

Description

[Technical field]

[0001] The present invention relates to a power transmission device that can arbitrarily transmit or interrupt a rotational force of an input member to an output member. [Background technology]

[0002] Generally, a power transmission device equipped on a motorcycle is used to selectively transmit or cut off the driving force of the engine to the transmission and drive wheels, and has an input member connected to the engine, an output member connected to the transmission and drive wheels, a clutch member connected to the output member, and a pressure member that can be moved toward or away from the clutch member. By bringing the pressure member toward the clutch member, the driving side clutch plate and the driven side clutch plate are pressed together to transmit the power, and by moving the pressure member away from the clutch member, the pressure force between the driving side clutch plate and the driven side clutch plate is released, thereby cutting off the transmission of the power.

[0003] As a conventional power transmission device, for example, as disclosed in Patent Document 1, a centrifugal clutch means is proposed which includes a weight member that can press the driving clutch plate and the driven clutch plate together by moving from an inner diameter side position to an outer diameter side position of the groove by centrifugal force accompanying rotation of the clutch housing. According to this conventional power transmission device, the weight member can be applied with centrifugal force by rotating the clutch housing with the drive of the engine, and the driving force of the engine can be transmitted to the wheels by pressing the driving clutch plate and the driven clutch plate together. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2013 / 183588 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above conventional power transmission device, since the weight member is made of a steel ball, a relatively large space is required for the steel ball to move, which may result in the device becoming large. For this reason, the applicant has earnestly studied ways to make the device smaller by using a weight member in the shape of a bridge having a front and back surface, but in this case, he has come to consider a configuration that includes a biasing member such as a spring to return the weight member to its initial position.

[0006] With this configuration, when the centrifugal force caused by the rotation of the clutch housing decreases, the biasing member can smoothly move the weight member from the outer diameter side position to the inner diameter side position. However, if a plurality of weight members are arranged around the circumferential direction of the holding member and each is movable in a radial direction, it is difficult to bias the weight members from the outer diameter side position toward the inner diameter side position with high accuracy using the biasing means.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a power transmission device that can precisely bias a weight member from an outer diameter side position toward an inner diameter side position and can stably move the weight member in response to centrifugal force. [Means for solving the problem]

[0008] The power transmission device according to the present invention comprises a clutch member that rotates together with an input member that rotates by the driving force of a vehicle engine, and is housed 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 arranged alternately with the driving side clutch plates attached and connected to an output member capable of rotating 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 pressed together to enable the driving force of the engine to be transmitted to the wheels, and a non-operating position in which the pressing 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, and a weight member that is movable from an inner diameter side position to an outer diameter side position by centrifugal force associated with the rotation of the clutch housing, and when the weight member is in the outer diameter side position, the driving side clutch plates and the driven side clutch plates are pressed together to enable the driving force of the engine to be transmitted to the wheels, and when the weight member is in the inner diameter side position, the driving side clutch plates and the driven side clutch plates are pressed together to enable the driving force of the engine to be transmitted to the wheels, and a centrifugal clutch means capable of releasing a pressure contact force between the driving side clutch plate and the driven side clutch plate to cut off the transmission of the driving force of the engine to the wheels, the centrifugal clutch means comprising a holding member which holds the weight member movably between the inner diameter side position and the outer diameter side position, a pressure contact member which moves in a stacking direction of the driving side clutch plate and the driven side clutch plate by the weight member moving from the inner diameter side position to the outer diameter side position to press the driving side clutch plate and the driven side clutch plate together, and a pressure contact member which holds the weight member in a front direction and a rear direction. and a biasing member which biases from the outer diameter side position toward the inner diameter side position, the weight member being accommodated in a plurality of accommodating portions formed in the circumferential direction of the holding member and movable in a radial direction, the weight member being formed with a plurality of recesses which open in the axial direction of the output member on one side surface in the axial direction of the output member, the biasing member extending radially within the recesses, an inner diameter side end of the biasing member abutting against an end wall surface formed radially inside the recesses, and an outer diameter side end of the biasing member abutting against an inner circumferential wall surface of the accommodating portion. [Brief description of the drawings]

[0009] [Figure 1] External view showing the power transmission device according to an embodiment of the present invention [Diagram 2] Cross-sectional view taken along line II-II in FIG. 1 [Diagram 3] Cross-sectional view taken along line III-III in FIG. 1 [Figure 4] Perspective view showing the clutch housing in the power transmission device [Diagram 5] Three-view drawing showing the first clutch member in the power transmission device [Figure 6] Perspective view showing the first clutch member [Figure 7] Three-view drawing showing the second clutch member in the power transmission device [Figure 8] Perspective view showing the second clutch member [Figure 9] Three-view drawing showing the pressure member in the power transmission device [Figure 10] Perspective view showing the pressure member [Figure 11] Longitudinal sectional view showing the centrifugal clutch means in the power transmission device [Figure 12] Partially cut-away perspective view showing the centrifugal clutch means [Figure 13] Three-view drawing showing the holding member constituting the centrifugal clutch means [Figure 14] Three-view drawing showing the support member constituting the centrifugal clutch means [Figure 15] Three-view drawing showing the pressure contact member constituting the centrifugal clutch means [Figure 16] Four-view drawing showing the weight member constituting the centrifugal clutch means [Figure 17] Cross-sectional view taken along line XVII-XVII in FIG. 16 [Figure 18] Plan view showing the state where the weight member in the centrifugal clutch means is at the inner diameter side position [Figure 19] Plan view showing the state where the weight member in the centrifugal clutch means is at the 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. [Diagram 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; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 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.

[0011] 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.

[0012] 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).

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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).

[0025] 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.

[0026] 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).

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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).

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] The auxiliary clutch plate 17 is made 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, the diameter is smaller than the driving side clutch plate 6 and the driven side clutch plate 7), and as shown in Figures 2 and 3, the output shaft 3 (output member) is inserted into its 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.

[0040] 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.

[0041] 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 pressing member 12 move in a direction away from each other. As a result, the pressing surface 12c of the pressing 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 presses the pressed surface 17b of the auxiliary clutch plate 17, so that the driving force of the engine E is transmitted to the driving wheels T.

[0042] Furthermore, in the first clutch member 4a of this embodiment, as shown in Figures 5 and 6, an abutment surface 4ad is formed on a part of the surface facing the pressure member 5, and in the pressure member 5, as shown in Figures 9 and 10, an abutment surface 5e is formed on a part of the surface facing the first clutch member 4a. When the first clutch member 4a, the second clutch member 4b and the pressure member 5 are assembled (a state in which there is no torque transmitted from the input gear 1 (input member) to the output shaft 3 (output member)), the abutment surface 4ad and the abutment surface 5e are in abutment with each other, as shown in Figures 2 and 3.

[0043] In this manner, when the abutment surface 4ad and the abutment surface 5e are in contact with each other, during the process in which the weight member 10 of the centrifugal clutch means 9 moves from the inner diameter side position (see Figure 22) to the intermediate position (see Figure 23) 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 not permitted, and therefore the operation of the pressure-assist cam is restricted.

[0044] 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).

[0045] Thus, in a state where the contact surface 4ad and the contact surface 5e are separated, in the process of the weight member 10 of the centrifugal clutch means 9 moving 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) increasing, relative movement between the first clutch member 4a and the pressure member 5 is allowed, so the operation of the cam for pressure contact assist is allowed.

[0046] 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 retained 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 easily and accurately attached to the weight member 10, and the manufacturing cost can be reduced.

[0047] 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 rollable while being in contact with the inner peripheral surface of the through hole 10a respectively. 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 retained at the rolling surface of the holding member 11 or the pressure contact member 12, the first spherical member 14 and the second spherical member 15 can be easily retained.

[0048] Furthermore, since the rolling surface of the holding member 11 or the pressure contact member 12 is formed in a groove shape (11b, 12b) along the moving direction of the weight member 10, smoother movement of the weight member 10 can be achieved while reliably retaining the second spherical member 15 on the large diameter opening side and the first spherical member 14 on the small diameter opening side respectively.

[0049] In addition, the weight member 10 according to the present embodiment is respectively accommodated in the accommodation portions 11a formed in a plurality across the circumferential direction of the holding member 11 and is movable in the radial direction. Further, a plurality of biasing members 16 are arranged in the circumferential direction between the inner peripheral wall surface 11aa of the accommodation 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.

[0050] Further, the weight member 10 according to the present embodiment is formed with an insertion portion 10b through which the biasing member 16 can be inserted while opening the surface facing the holding member 11. Therefore, the biasing member 16 can be easily assembled to the weight member 10. Furthermore, the weight member 10 according to the present embodiment is formed with a groove 10c in the direction from the inner diameter side position toward 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. Therefore, the weight member 10 can be stably moved.

[0051] 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 the rolling surface (groove shape 12b) of the pressing member 12 and is rollable, 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 the rolling surface (groove shape 11b) of the holding member 11 and is rollable. Therefore, the weight member 10 can be moved more stably.

[0052] In particular, the retaining member 11 or the pressing member 12 has a groove shape (11b, 12b) along the movement direction of the weight member 10, and the groove shape (11b, 12b) is made into the rolling surface of the first spherical member 14 or the second spherical member 15, so that the movement of the weight member 10 can be made smoother. Furthermore, the first spherical members 14 and the second spherical members 15 according to this embodiment are each formed in multiples along the circumferential direction of the retaining member 11 (the width direction of the weight member 10), so that the movement of the weight member 10 can be made even more stable.

[0053] While the present embodiment has been described above, the present invention is not limited thereto, and may be, for example, one that does not have the pressure contact assist cam (gradient surface 4aa and gradient surface 5a) and the back torque limiter cam (gradient surface 4ab and gradient surface 5b), or one that does not have the auxiliary clutch plate 17. Also, in this embodiment, the through hole 10a is formed in a tapered shape, but it may be an insertion hole of the same diameter from one opening to the other opening, and the first spherical member 14 and the second spherical member 15 may be retained by other retaining means and methods, such as by crimping.

[0054] 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 for automobiles, three- or four-wheeled buggies, general-purpose machines, and the like, in addition to motorcycles. [Industrial Applicability]

[0055] The centrifugal clutch means is configured to include a retaining member that holds the weight member movably between an inner diameter side position and an 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 the weight members are respectively accommodated in a plurality of accommodating sections formed around the circumferential direction of the retaining member and are movable in the radial direction, and the biasing members are arranged in a plurality of units in the circumferential direction between the inner wall surface of the accommodating section and the weight member to bias the weight member from the outer diameter side position toward the inner diameter side position, and the power transmission device can also be applied to power transmission devices with different external shapes or with other functions added, etc. [Explanation of symbols]

[0056] 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 10aa One opening 10ab other opening 10b Insertion part 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 S clutch spring

Claims

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 enable transmission of 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 interrupt transmission of the driving force of the engine to the wheels; a centrifugal clutch means including a weight member 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, the driving side clutch plate and the driven side clutch plate are pressed together to enable transmission of the driving force of the engine to the wheels, and 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 to interrupt transmission of the driving force of the engine to the wheels; A power transmission device comprising: The centrifugal clutch means comprises: a holding 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 a stacking direction of the driving side clutch plates and the driven side clutch plates by moving the weight member from the inner diameter side position to the outer diameter side position to press the driving side clutch plates and the driven side clutch plates into contact with each other; a biasing member that biases the weight member from the outer diameter side position toward the inner diameter side position, The weight members are accommodated in a plurality of accommodation portions formed in a circumferential direction of the holding member and are movable in a radial direction, a plurality of recesses that open in the axial direction of the output member are formed on one side surface of the weight member in the axial direction of the output member; The biasing member extends radially within the recess, An inner diameter side end of the biasing member abuts against an end wall surface formed on the radially inner side of the recess, An outer diameter side end of the biasing member abuts against an inner circumferential wall surface of the accommodating portion.

2. The power transmission device according to claim 1 , wherein the recesses are provided on both sides of a center line of the weight member in the circumferential direction and extending in a radial direction.

3. 2. The power transmission device as described in claim 1, wherein a first spherical member having a portion protruding from one opening of a through hole formed in the weight member and capable of rolling in contact with the rolling surface of the pressure contacting member, and a second spherical member having a portion protruding from the other opening of the through hole formed in the weight member and capable of rolling in contact with the rolling surface of the retaining member are each provided in plurality in the circumferential direction of the retaining member.

4. The power transmission device according to claim 3 , wherein the recess is provided at a position sandwiched between a plurality of the second spherical members provided in a circumferential direction of the holding member.

5. the centrifugal clutch means has a spherical member that opens into one surface of the weight member in the axial direction of the output member, partially protruding from an opening of one of a plurality of through holes formed in the circumferential direction, and that is capable of rolling in contact with the rolling surface of the holding member, The power transmission device according to claim 1 , wherein the recess is provided in a portion sandwiched between a plurality of the through holes.

6. The power transmission device according to claim 1 , wherein the end wall surface is closer to an inner diameter side end face of the weight member than to an outer diameter side end face of the weight member.

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