Power transmission device

Abstract

The present invention provides a power transmission device that can improve operability by suppressing suddenness during power transmission. The power transmission device has: a linkage member (9) that can move a pressure member (5) from an inoperable position to an operable position; a release spring (m) that can apply a biasing force while allowing the linkage member and the pressure member to move until the driving-side clutch plate (6) and the driven-side clutch plate (7) reach an engaged state before being crimped; and a clutch spring (11) that contracts during the movement of the linkage member to further move the pressure member after the driving-side clutch plate and the driven-side clutch plate reach the engaged state, and the clutch spring can apply a crimping force to the driving-side clutch plate and the driven-side clutch plate while allowing the linkage member and the pressure member to move. The clutch spring has a set load that is set to be less than the maximum load of the release spring.

Description

[0001] This application is a divisional application of the invention patent application with the original application number 201980079472.1 (PCT application number: PCT / JP2019 / 047408, application date: December 4, 2019, invention title: Power transmission device). Technical Field

[0002] The present invention relates to a power transmission device capable of appropriately transmitting or stopping the transmission of the rotational power of an input member to an output member. Background Art

[0003] Generally, a motorcycle has a power transmission device for appropriately transmitting or stopping the transmission of the driving force of an engine to a transmission and a driving wheel. The power transmission device includes: an input member connected to the engine side; an output member connected to the transmission and the driving wheel side; a clutch member connected to the output member; and a pressure member capable of moving toward or away from the clutch member. The power transmission device is configured to transmit power by moving the pressure member toward the clutch member to press a driving-side clutch plate and a driven-side clutch plate against each other, and is configured to stop the transmission of power by moving the pressure member away from the clutch member to release the pressing force between the driving-side clutch plate and the driven-side clutch plate.

[0004] In an existing power transmission device disclosed in, for example, Patent Document 1, a power transmission device including a weight member is proposed. The weight member can press a driving-side clutch plate and a driven-side clutch plate against each other by moving from a radially inner position to a radially outer position in a groove portion due to the centrifugal force generated when the clutch housing rotates. With the existing power transmission device, since the clutch housing rotates as the engine is driven, the centrifugal force can be applied to the weight member by pressing the driving-side clutch plate and the driven-side clutch plate against each other, and the driving force of the engine can be transmitted to the wheel.

[0005] The existing power transmission device further includes: a release spring that is compressed when the linkage member moves and the pressure member moves from a non-operating position toward an operating position, and the release spring can apply a driving force while allowing the linkage member and the pressure member to move until the driving-side clutch plate and the driven-side clutch plate reach an engaged state before pressing against each other; and a clutch spring that is compressed during the movement of the linkage member after the driving-side clutch plate and the driven-side clutch plate have reached the engaged state, and the clutch spring can apply a pressing force between the driving-side clutch plate and the driven-side clutch plate while allowing the linkage member to move.

[0006] Citation List

[0007] Patent Document

[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-155884 Summary of the Invention

[0009] Technical Problem

[0010] However, the existing power transmission device has the following problems.

[0011] If the difference between the load at the end of the compression of the release spring (maximum load) (see P1 in Figure 34 ) and the load at the start of the compression of the clutch spring (set load) (see P2 in the figure) is large, then during the process in which the linkage member moves and the pressure member moves from the non-operating position toward the operating position as the engine speed increases, after the compression of the release spring has been completed and before the compression of the clutch spring starts, a dead zone occurs that stops the movement of the linkage member (stops at the movement amount α1 in the figure).

[0012] Then, when the engine speed further increases and the pressing load applied to the linkage member reaches the set load of the clutch spring (at time P2 in the figure), the compression of the clutch spring starts, so the linkage member starts moving again and passes through the dead zone. However, since the clutch plates are pressed against each other and power is transmitted after passing through the dead zone, an unexpected feeling occurs when power is transmitted and the operability may be affected.

[0013] The present invention has been made in view of such circumstances, and an object thereof is to provide a power transmission device that can suppress the unexpected feeling during power transmission and can improve the operability.

[0014] Solution to the Problem

[0015] According to the invention of the first aspect, a power transmission device includes: a clutch housing that rotates together with an input member which rotates by the driving force of an engine of a vehicle, and a plurality of driving-side clutch plates are attached to the clutch housing; a clutch member to which a plurality of driven-side clutch plates formed alternately with the plurality of driving-side clutch plates of the clutch housing are attached, and the clutch member is coupled to an output member capable of rotating a wheel of the vehicle; a pressure member that can move between a working position and a non-working position, in the working position, the pressure member presses the plurality of driving-side clutch plates and the plurality of driven-side clutch plates against each other to be able to transmit the driving force of the engine to the wheel, and in the non-working position, the pressure member releases the pressing force between the plurality of driving-side clutch plates and the plurality of driven-side clutch plates to be able to stop transmitting the driving force of the engine to the wheel; a weight member disposed in a groove portion extending in a radial direction of the clutch housing, and the weight member can move from a radially inner position to a radially outer position in the groove portion due to centrifugal force generated when the clutch housing rotates; a linkage member that can move the pressure member from the non-working position to the working position when the weight member moves from the radially inner position to the radially outer position; a release spring that can hold the pressure member in the non-working position, the release spring is compressed when the linkage member moves and the pressure member moves from the non-working position toward the working position, and the release spring can apply a driving force while allowing the linkage member and the pressure member to move until the plurality of driving-side clutch plates and the plurality of driven-side clutch plates reach an engaged state before the plurality of driving-side clutch plates and the plurality of driven-side clutch plates press against each other; and a clutch spring that is compressed during the movement of the linkage member after the plurality of driving-side clutch plates and the plurality of driven-side clutch plates have reached the engaged state, and the clutch spring can apply a pressing force between the plurality of driving-side clutch plates and the plurality of driven-side clutch plates while allowing the linkage member to move. A set load of the clutch spring is set to be less than a maximum load of the release spring.

[0016] According to the invention of the second aspect, the power transmission device according to the first aspect includes a buffer member that can apply a driving force while allowing the linkage member and the pressure member to move by being compressed during the movement of the linkage member and the movement of the pressure member from the non-working position toward the working position.

[0017] According to the invention of the third aspect, in the power transmission device described in the second aspect, the buffer member is constituted by a spring having a set load, and the set load causes the spring to be compressed before the clutch spring starts to be compressed.

[0018] Advantageous effects of the invention

[0019] According to the invention of the first aspect, it is possible to avoid the occurrence of a dead zone and improve the operability by suppressing the unexpected feeling during power transmission, because the set load of the clutch spring is set to be smaller than the maximum load of the release spring. Therefore, the compression of the release spring and the compression of the clutch spring are continuously performed, and the linkage member moves continuously.

[0020] According to the invention of the second aspect, when the buffer member or the clutch spring is continuously compressed during the compression of the release spring, a dead zone can be avoided, and the unexpected feeling during power transmission can be further suppressed, and the operability can be improved, because the power transmission device includes a buffer member that can apply a driving force by being compressed while allowing the linkage member and the pressure member to move during the movement of the linkage member and the movement of the pressure member from the non-operating position toward the operating position.

[0021] According to the invention of the third aspect, the unexpected feeling during power transmission can be reliably suppressed, because the buffer member is constituted by a spring having a set load, and the set load causes the spring to be compressed before the clutch spring starts to be compressed. Description of the drawings

[0022] Figure 1 is an external view of a power transmission device according to an embodiment of the present invention.

[0023] Figure 2 is a longitudinal sectional view illustrating the internal structure of the power transmission device.

[0024] Figure 3 is a schematic view of a driving-side clutch plate, a driven-side clutch plate, a reverse torque transmission cam, etc. of the power transmission device.

[0025] Figure 4 is a perspective view of a housing portion of a clutch housing of the power transmission device.

[0026] Figure 5 is a perspective view of a cover portion of a clutch housing of the power transmission device.

[0027] Figure 6 is a three-side view of a first clutch member of the power transmission device.

[0028] Figure 7 ​​​​​​​is a three-side view of the second clutch member of the power transmission device.

[0029] Figure 8 is a three-side view of the pressure member of the power transmission device.

[0030] Figure 9 is a perspective view illustrating the first clutch member, the second clutch member, the pressure member, and the bearing retaining member of the power transmission device before assembly.

[0031] Figure 10 is a perspective view illustrating the first clutch member, the second clutch member, the pressure member, and the bearing retaining member of the power transmission device before assembly.

[0032] Figure 11 is a perspective view illustrating the first clutch member, the second clutch member, the pressure member, and the bearing retaining member of the power transmission device after assembly.

[0033] Figure 12 is a three-side view of the bearing retaining member of the power transmission device.

[0034] Figure 13 is a schematic diagram illustrating the function of the crimping assist cam of the power transmission device.

[0035] Figure 14 is a schematic diagram illustrating the function of the reverse torque limiter cam of the power transmission device.

[0036] Figure 15 is a plan view of the first clutch member and the second clutch member of the power transmission device assembled together, illustrating a state where one side surface of the protrusion contacts the first contact surface (torque transmission portion).

[0037] Figure 16 is a plan view of the first clutch member and the second clutch member of the power transmission device assembled together, illustrating a state where the other side surface of the protrusion contacts the second contact surface (movement amount limiting portion).

[0038] Figure 17 is a schematic diagram illustrating the function of the reverse torque transmission cam of the power transmission device in a state before the reverse torque transmission cam starts to operate.

[0039] Figure 18 is a schematic diagram illustrating the function of the reverse torque transmission cam of the power transmission device in a state after the reverse torque transmission cam has started to operate.

[0040] Figure 19 ​​​​​​​​​​​​is a schematic view showing a state in which a buffer member of a power transmission device according to another embodiment of the present invention is accommodated in an accommodation recess.

[0041] Figure 20 is a schematic view showing a state in which a release spring of a power transmission device applies an urging force to both a bearing holding member and a pressure member.

[0042] Figure 21 is a three-side view of a release spring of a power transmission device.

[0043] Figure 22 is a graph showing the movement amount and pressing load of an interlocking member of a power transmission device.

[0044] Figure 23 is a graph showing the movement amount and pressing load of an interlocking member of a power transmission device according to another embodiment of the present invention.

[0045] Figure 24 is a longitudinal sectional view of a power transmission device according to another embodiment of the present invention.

[0046] Figure 25 is a longitudinal sectional view of a power transmission device according to another embodiment of the present invention.

[0047] Figure 26 is a longitudinal sectional view of a power transmission device according to another embodiment of the present invention.

[0048] Figure 27 is a longitudinal sectional view of a power transmission device according to another embodiment of the present invention (provided with a buffer member 12' and including a pull-type actuating member 10").

[0049] Figure 28 shows a plan view and a side view of a buffer member of a power transmission device.

[0050] Figure 29 is a perspective view of a buffer member of a power transmission device.

[0051] Figure 30 is a longitudinal sectional view of a power transmission device according to another embodiment of the present invention (provided with a buffer member 12 and including a pull-type actuating member 10").

[0052] Figure 31 is a longitudinal sectional view of a power transmission device according to another embodiment of the present invention (a reverse torque transmission cam is provided at the outer edge of the first clutch member 4a).

[0053] Figure 32 ​​​​​​​​​​​​​is a longitudinal sectional view of a power transmission device according to another embodiment of the present invention (a reverse torque transmission cam is provided at the outer edge of the first clutch member 4a, and a buffer member composed of a conical disc spring is provided).

[0054] Figure 33 is a longitudinal sectional view of a power transmission device according to another embodiment of the present invention (a reverse torque transmission cam is provided at the outer edge of the first clutch member 4a, and a buffer member composed of a corrugated spring is provided).

[0055] Figure 34 is a graph showing the amount of movement and pressing load of the linkage member of the existing power transmission device.

[0056] List of Reference Numerals

[0057] 1 Input gear (input member)

[0058] 2 Clutch housing

[0059] 2a Housing portion

[0060] 2b Cover portion

[0061] 3 Output shaft (output member)

[0062] 4a First clutch member

[0063] 4aa Inclined surface (crimping assist cam)

[0064] 4ab Inclined surface (reverse torque limiter cam)

[0065] 4ac Flange surface

[0066] 4ad Insertion hole

[0067] 4b Second clutch member

[0068] 4ba Spline fitting portion

[0069] 4bb Pressing portion

[0070] 4c Receiving recess

[0071] 4d Recess

[0072] 4da Inner peripheral wall surface

[0073] 5 Pressure member

[0074] 5a Inclined surface (crimping assist cam)

[0075] 5b Inclined surface (reverse torque limiter cam)

[0076] ​​5c Flange surface

[0077] 6 Driving side clutch plate

[0078] 7 Driven side clutch plate

[0079] 8 Counterweight member

[0080] 9 Linkage member

[0081] 10 Actuating member

[0082] 11 Clutch spring

[0083] 12 Buffer member (conical disc spring)

[0084] 12' Buffer member (wave spring)

[0085] 12'a Notch portion

[0086] C Bearing retaining member

[0087] Ca Open end portion

[0088] Cb Top portion

[0089] Cc Communication hole

[0090] K Groove portion

[0091] K1 Cam surface

[0092] K2 Wall surface

[0093] T Protrusion

[0094] T1 Cam surface

[0095] T2 Wall surface

[0096] F Protrusion

[0097] G Protrusion

[0098] G1 First contact surface

[0099] G2 Second contact surface

[0100] m Release spring

[0101] r Oil flow path Detailed implementation mode

[0102] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0103] The power transmission device according to the present embodiment is a device provided in a vehicle such as a motorcycle, and is used to appropriately transmit or stop transmitting the driving force of the engine to the transmission or toward the drive wheel side. AsFigures 1 to 12 As shown, the power transmission device mainly includes: a clutch housing 2, in which an input gear 1 (input member) that rotates by the driving force of the vehicle's engine is formed; clutch members (a first clutch member 4a and a second clutch member 4b); a pressure member 5 attached to the right side of the clutch members (the first clutch member 4a and the second clutch member 4b); a plurality of driving-side clutch plates 6; a plurality of driven-side clutch plates 7; a weight member 8 composed of a steel ball member that can move (roll) in the radial direction in the clutch housing 2; a linkage member 9; and an actuating member 10 that can be actuated by hand or an actuator (not shown). In the figure, the symbol S represents a spring damper, the symbol B1 represents a roller bearing, and the symbols B2 and B3 respectively represent thrust bearings. Figure 2

[0104] When the driving force (rotational force) transmitted from the engine is input, the input gear 1 can rotate around the output shaft 3. The input gear 1 is connected to the clutch housing 2 via a rivet R or the like. The clutch housing 2 includes a housing portion 2a and a cover portion 2b. The housing portion 2a is composed of a cylindrical member (open on the right side in Figure 2 ), and is connected to the input gear 1, and the cover portion 2b is attached to close the opening of the housing portion 2a. Due to the driving force of the engine, the clutch housing 2 can rotate together with the rotation of the input gear 1.

[0105] As Figure 4 shown, a plurality of cutouts 2aa are formed in the housing portion 2a of the clutch housing 2 so as to be arranged in the circumferential direction, and a plurality of driving-side clutch plates 6 are attached to be assembled into the cutouts 2aa. Each driving-side clutch plate 6 is composed of a substantially annular plate material, is configured to be able to rotate together with the rotation of the clutch housing 2, and slide in the axial direction ( Figure 2 the left-right direction of

[0106] ). In addition, as Figure 5 shown, a plurality of groove portions 2ba extending in the radial direction of the cover portion 2b are formed in the bottom surface of the cover portion 2b of the clutch housing 2. The weight member 8 is provided in each of the plurality of groove portions 2ba. In a state where the clutch housing 2 is stopped (engine stopped or idling state) and a state where the clutch housing 2 rotates at a low speed, the weight member 8 is located at a radially inner position ( Figure 2 the position shown). In a state where the clutch housing 2 rotates at a high speed, the weight member 8 is located at a radially outer position.

[0107] A plurality of driven-side clutch plates 7 formed alternately with the drive-side clutch plates 6 of the clutch housing 2 are attached to the clutch members (the first clutch member 4a and the second clutch member 4b). The clutch members are coupled to an output shaft 3 (output member) capable of rotating the wheels of the vehicle. The clutch members are constituted by assembling two members, the first clutch member 4a and the second clutch member 4b.

[0108] As Figure 6 shown, the first clutch member 4a is constituted by a disk-shaped member, and a flange surface 4ac is formed along the peripheral portion of the disk-shaped member. The first clutch member 4a is configured such that the output shaft 3 is inserted into an insertion hole 4ad formed at its center (see Figure 2 and Figure 6 ), and the first clutch member 4a and the output shaft 3 are coupled to each other in the rotational direction because the gears formed therein mesh with each other. As Figure 6 , Figure 9 and Figure 10 shown, in the first clutch member 4a, an inclined surface 4aa constituting a crimping assist cam and an inclined surface 4ab constituting a reverse torque limiter cam are formed.

[0109] As Figure 7 shown, the second clutch member 4b is constituted by an annular member, and is configured such that the driven-side clutch plates 7 are attached to a spline fitting portion 4ba formed in its outer peripheral surface by spline fitting (see Figure 2 and Figure 7 ). As Figures 9 to 11 shown, the pressure member 5 is assembled with the clutch members (the first clutch member 4a and the second clutch member 4b). The plurality of drive-side clutch plates 6 and driven-side clutch plates 7 in an alternately stacked state are attached between the flange surface 5c of the pressure member 5 (see Figure 2 and Figure 8 ) and the flange surface 4ac of the first clutch member 4a (see Figure 2 and Figure 6 ).

[0110] As Figure 8 shown, the pressure member 5 is constituted by a disk-shaped member, and the flange surface 5c is formed along its peripheral portion. The pressure member 5 is movable between a working position and a non-working position (see Figure 2 ). In the working position, the pressure member 5 presses the drive-side clutch plates 6 and the driven-side clutch plates 7 against each other to enable the transmission of the driving force of the engine to the wheels. In the non-working position, the pressure member 5 releases the pressing force between the drive-side clutch plates 6 and the driven-side clutch plates 7 to enable the stopping of the transmission of the driving force of the engine to the wheels.

[0111] More specifically, as Figure 7 ,Figure 9 and Figure 10 As shown in Figure 10 , the spline fitting portion 4ba formed in the second clutch member 4b has a protrusion / depression shape integrally formed along substantially the entire circumference of the outer peripheral side surface of the second clutch member 4b. When the driven-side clutch disc 7 is fitted into the groove of the spline fitting portion 4ba, the movement of the driven-side clutch disc 7 in the rotational direction is restricted, while allowing the driven-side clutch disc 7 to move in the axial direction relative to the second clutch member 4b, and the driven-side clutch disc 7 can rotate together with the second clutch member 4b.

[0112] The driven-side clutch discs 7 are stacked alternately with the drive-side clutch discs 6, and the clutch discs 6 and 7 can be pressed against each other, or the pressing force between them can be released. That is, both the clutch discs 6 and 7 are allowed to slide in the axial direction of the second clutch member 4b. When the pressure member 5 moves leftward in Figure 2 and its flange surface 5c moves toward the flange surface 4ac of the first clutch member 4a, both the clutch discs 6 and 7 are pressed against each other to transmit the rotational force of the clutch housing 2 to the output shaft 3 via the second clutch member 4b and the first clutch member 4a. When the pressure member 5 moves rightward in Figure 2 and its flange surface 5c and the flange surface 4ac of the first clutch member 4a become separated from each other, the pressing force between the clutch discs 6 and 7 is released, and the first clutch member 4a and the second clutch member 4b stop following the rotation of the clutch housing 2 and stop transmitting the rotational force to the output shaft 3.

[0113] In a state where the drive-side clutch disc 6 and the driven-side clutch disc 7 are pressed against each other, the rotational force (engine driving force) input to the clutch housing 2 is transmitted to the wheel side via the output shaft 3 (output member). In a state where the pressing between the drive-side clutch disc 6 and the driven-side clutch disc 7 is released, the rotational force (engine driving force) input to the clutch housing 2 can be prevented from being transmitted to the output shaft 3 (output member).

[0114] In addition, as shown in Figure 6 , Figure 8 , Figure 9 and Figure 10 in the present embodiment, inclined surfaces 4aa and 4ab are formed in the first clutch member 4a, and inclined surfaces 5a and 5b facing the inclined surfaces 4aa and 4ab are formed in the pressure member 5. That is, the inclined surface 4aa and the inclined surface 5a contact each other to constitute a pressing assist cam, and the inclined surface 4ab and the inclined surface 5b contact each other to constitute a reverse torque limiter cam.

[0115] As shown in Figure 13As shown, when the engine speed increases and the rotational force input to the input gear 1 and the clutch housing 2 becomes capable of being transmitted to the output shaft 3 via the first clutch member 4a and the second clutch member 4b, a rotational force in the direction a is applied to the pressure member 5 (the counterweight member 8 is in the radially outer position). Therefore, due to the action of the crimping auxiliary cam, a force in the direction c in the figure is generated in the pressure member 5. Accordingly, the flange surface 5c of the pressure member 5 moves in a direction further toward the flange surface 4ac of the first clutch member 4a ( Figure 2 to the left in the figure), and the pressure member 5 increases the crimping force between the driving-side clutch disc 6 and the driven-side clutch disc 7.

[0116] On the other hand, when the vehicle is running, when the rotational speed of the output shaft 3 exceeds the rotational speeds of the input gear 1 and the clutch housing 2 and a reverse torque in the Figure 14 direction b in the figure is generated, due to the action of the reverse torque limiter cam, the pressure member 5 moves in the direction d in the figure to release the crimping force between the driving-side clutch disc 6 and the driven-side clutch disc 7. Thereby, damage to the power transmission device and the power source (engine side) caused by the reverse torque can be avoided.

[0117] The counterweight member 8 is provided in a groove portion 2ba extending in the radial direction of the clutch housing 2 (the cover portion 2b in the present embodiment). The counterweight member 8 moves from the radially inner position (see Figure 2 ) to the radially outer position in the groove portion 2ba due to the centrifugal force generated when the clutch housing 2 rotates, so as to press the driving-side clutch disc 6 and the driven-side clutch disc 7 against each other. That is, the rolling surface (bottom surface) of the groove portion 2ba for the counterweight member 8 to roll has an upward slope from the radially inner position toward the radially outer position. When the clutch housing 2 stops, the counterweight member 8 is held in the radially inner position due to the urging force of the release spring m. When the clutch housing 2 rotates, centrifugal force is applied to the counterweight member 8, and when the clutch housing 2 reaches a predetermined rotational speed, the counterweight member 8 moves along the upward slope to the radially outer position.

[0118] The linkage member 9 is constituted by an annular member provided in the clutch housing 2 (cover portion 2b). The linkage member 9 is fitted and coupled to a groove portion formed in the inner peripheral surface of the cover portion 2b, can rotate together with the clutch housing 2, and can move in the Figure 2 left-right direction. When the counterweight member 8 moves from the radially inner position to the radially outer position, the linkage member 9 moves leftward in the Figure 2 figure against the urging forces of the clutch spring 11 and the release spring m, and can press the pressure member 5 to move the pressure member 5 from the non-operating position to the operating position.

[0119] The actuating member 10 can be operated by hand or an actuator (see Figure 2) is composed of the operating components, and the pressing force between the driving-side clutch plate 6 and the driven-side clutch plate 7 of the pressure member 5 can be released ( Figure 2 in the right direction in). When performing a shift operation, for example, by operating the clutch pedal, clutch lever, etc. of the vehicle or by the operation of the actuator, the actuating member 10 moves Figure 2 rightward in to contact the pressure member 5 via the bearing holding member C and move the pressure member 5 from the working position to the non-working position. Therefore, by releasing the pressing force between the driving-side clutch plate 6 and the driven-side clutch plate 7, the actuating member 10 can disengage the clutch (stop power transmission).

[0120] As Figure 2 shown, the bearing holding member C is coupled to the actuating member 10 and holds the bearing B1 disposed between the actuating member 10 and the pressure member 5. As Figure 12 shown, the bearing holding member C is composed of a tubular member with one end open, and includes an open end Ca and a top Cb located on the opposite side of the open end Ca. The bearing B1 according to the present embodiment is attached to the top Cb side in the bearing holding member C, and the tubular portion extends from the diameter-increasing portion toward the open end Ca. In addition, although a ball bearing is used as the bearing B1 according to the present embodiment, another bearing such as a needle bearing can be used, for example.

[0121] In addition, as Figure 2 and Figure 20 shown, the open end Ca of the bearing holding member C according to the present embodiment is fitted and attached to the recess 4d formed in the clutch member (the first clutch member 4a), and is assembled with the inner peripheral wall surface 4da of the recess 4d by socket joint (fitting joint). The recess 4d is formed by a circular depression, the shape of which is similar to the outer shape of the open end Ca and has substantially the same dimensions as the outer shape of the open end Ca (strictly speaking, the dimensions are slightly larger than the open end Ca). By fitting the bearing holding member C into the recess 4d, it is positioned and centered with respect to the power transmission device.

[0122] During a shift operation, when the actuating member 10 moves Figure 2 rightward in, for example, by operating the clutch pedal, clutch lever, etc. of the vehicle or by the operation of the actuator, the bearing holding member C moves together and contacts the pressure member 5 to move the pressure member 5 from the working position to the non-working position. Therefore, by releasing the pressing force between the driving-side clutch plate 6 and the driven-side clutch plate 7, the clutch is disengaged (power transmission is stopped).

[0123] The release spring m can hold the pressure member 5 in the non-operating position and is compressed when the linkage member 9 moves and the pressure member 5 moves from the non-operating position toward the operating position. The release spring m can apply a driving force while allowing the linkage member 9 and the pressure member 5 to move until the driving-side clutch plate 6 and the driven-side clutch plate 7 reach the engaged state (the distance between the driving-side clutch plate 6 and the driven-side clutch plate 7 is zero and the state immediately before power transmission due to crimping) before pressing against each other.

[0124] In addition, as Figure 21 shown, the release spring m according to the present embodiment is constituted by a conical disc spring, and the conical disc spring can generate a driving force due to the displacement between the middle portion ma and the peripheral portion mb. As Figure 2 and Figure 20 shown, the middle portion ma is attached to the top Cb of the bearing holding member C, and the peripheral portion mb is attached to the pressure member 5. The pressure member 5 has a protruding portion 5d protruding annularly, and the peripheral portion mb of the release spring m is engaged with and attached to an annular member g (for example, a spring ring, etc.) attached to the protruding portion 5d. Therefore, the release spring m according to the present embodiment is attached to both the bearing holding member C and the pressure member 5, applies a driving force (the driving force in the orientation indicated by the numeral a2 in Figure 20 ) to the pressure member 5, and can apply a driving force (the driving force in the orientation indicated by the symbol a1 in the figure) to the bearing holding member C to transmit the driving force to the actuating member 10.

[0125] The clutch spring 11 is constituted by a helical spring disposed between the linkage member 9 and the pressure member 5. When the linkage member 9 moves, the clutch spring 11 can press the pressure member 5 to move the pressure member 5 in the direction in which the driving-side clutch plate 6 and the driven-side clutch plate 7 press against each other. In addition, when the actuating member 10 operates, the clutch spring 11 can absorb the pressing force applied by the pressure member 5 to the linkage member 9.

[0126] The clutch spring 11 according to the present embodiment is compressed during the movement of the linkage member 9, and can apply a pressing force between the driving-side clutch plate 6 and the driven-side clutch plate 7 while allowing the linkage member 9 to move before the driving-side clutch plate 6 and the driven-side clutch plate 7 reach the above-mentioned engaged state.

[0127] That is, when the counterweight member 8 moves from the radially inner position to the radially outer position and the linkage member 9 is pressed by the counterweight member 8 when the clutch housing 2 rotates, the pressing force is transmitted to the pressure member 5 via the clutch spring 11, causing the pressure member 5 to move in Figure 2It moves leftward in the figure, and presses the driving-side clutch plate 6 and the driven-side clutch plate 7 against each other. When the actuating member 10 is actuated in this state, although the pressure member 5 moves rightward in the figure due to the pressing force of the actuating member 10, the pressing force applied to the linkage member 9 is absorbed by the clutch spring 11, and the position of the linkage member 9 (the position of the counterweight member 8) is maintained.

[0128] Here, the power transmission device according to the present embodiment includes a reverse torque transmission cam (cam surfaces K1 and T1), and when a rotational force is input to the first clutch member 4a via the output shaft 3 (output member), the reverse torque transmission cam can move the second clutch member 4b to press the driving-side clutch plate 6 and the driven-side clutch plate 7 against each other. As Figure 6 , Figure 7 , Figure 9 and Figure 10 shown, the reverse torque transmission cam is composed of cam surfaces (K1, T1) respectively integrally formed on the mating surfaces (mating surfaces when combined) of the first clutch member 4a and the second clutch member 4b.

[0129] As Figure 6 and Figure 9 shown, the cam surface K1 is composed of a plurality of inclined surfaces formed along the entire circumference of the radial inner side of the flange surface 4ac of the first clutch member 4a (mating surface with the second clutch member 4b). The cam surface K1 is formed in one end surface of each of a plurality of groove portions K formed annularly along the peripheral portion of the first clutch member 4a. That is, a plurality of groove portions K are formed in the first clutch member 4a so as to be arranged in its circumferential direction, and one end surface of each groove portion K is the inclined surface of the cam surface K1 constituting the reverse torque transmission cam. The other end surface of each groove portion K is a wall surface K2 extending in the axial direction of the first clutch member 4a.

[0130] As Figure 7 and Figure 10 shown, the cam surface T1 is composed of a plurality of inclined surfaces formed along the entire circumference of the bottom surface of the second clutch member 4b (mating surface with the first clutch member 4a). The cam surface T1 is formed in one end surface of each of a plurality of protrusions T formed annularly along the bottom surface of the second clutch member 4b. That is, a plurality of protrusions T are formed in the second clutch member 4b so as to be arranged in its circumferential direction, and one end surface of each protrusion T is the inclined surface of the cam surface T1 constituting the reverse torque transmission cam. The other end surface of each protrusion T is a wall surface T2 extending in the axial direction of the second clutch member 4b.

[0131] As Figure 17As shown, when the protrusion T is assembled into the groove K to couple the first clutch member 4a and the second clutch member 4b to each other, the cam surface K1 and the cam surface T1 face each other to form a reverse torque transmission cam, and the wall surface K2 and the wall surface T2 face each other at a predetermined distance therebetween. When a rotational force is input to the first clutch member 4a via the output shaft 3, since the first clutch member 4a rotates relative to the second clutch member 4b, as Figure 18 shown, due to the cam action of the cam surface K1 and the cam surface T1, the second clutch member 4b moves relative to the first clutch member 4a in Figure 2 and Figure 18 to the right.

[0132] As Figure 7 shown, the pressing portion 4bb is formed in the second clutch member 4b on the extension line of the spline fitting portion 4ba. When the second clutch member 4b moves to the right in Figure 2 , the pressing portion 4bb presses the leftmost driven-side clutch plate 7 in the figure in the same direction, and the driven-side clutch plate 7 is one of the driving-side clutch plate 6 and the driven-side clutch plate 7 attached in a stacked state. Therefore, even when the pressure member 5 is in the non-operating position, the driving-side clutch plate 6 and the driven-side clutch plate 7 can be pressed against each other, and when a rotational force is input from the output shaft 3 (output member), the rotational force can be transmitted to the engine side to apply engine braking.

[0133] In particular, the reverse torque transmission cam according to the present embodiment can move the second clutch member 4b in the direction toward the linkage member 9 ( Figure 2 to the right in the figure) to maintain the contact between the linkage member 9 and the weight member 8. That is, when the reverse torque transmission cam starts to operate and moves the second clutch member 4b to the right in Figure 2 , the reverse torque transmission cam presses the driving-side clutch plate 6 and the driven-side clutch plate 7 against each other and presses the pressure member 5 in the same direction. Therefore, the pressing force is transmitted to the linkage member 9 via the clutch spring 11, and the contact between the linkage member 9 and the weight member 8 is maintained.

[0134] If the linkage member 9 and the weight member 8 are separated from each other when the reverse torque transmission cam operates, then even when the weight member 8 subsequently moves between the radially inner position and the radially outer position as the clutch housing 2 rotates, it is impossible for the linkage member 9 to follow the movement. In contrast, in the present embodiment, the contact between the linkage member 9 and the weight member 8 can be maintained even when the reverse torque transmission cam operates, so that the linkage member 9 can stably follow the movement of the weight member 8.

[0135] In addition, the plurality of cam surfaces K1 and T1 of the reverse torque transmission cam according to the present embodiment are formed along the annular shape of the driven-side clutch plate 7 attached to the second clutch member 4b. That is, the cam surfaces K1 and T1 are formed along the projected image shape (annular shape) of the driven-side clutch plate 7, and when the reverse torque transmission cam operates, the driven-side clutch plate 7 is pressed by the pressing portion 4bb. Therefore, due to the cam action of the reverse torque transmission cam, the pressing portion 4bb can apply a substantially uniform pressing force to the driven-side clutch plate 7, and can more effectively press the driving-side clutch plate 6 and the driven-side clutch plate 7 against each other.

[0136] In addition, the reverse torque transmission cam (the cam composed of the cam surface K1 and the cam surface T1) according to the present embodiment can start operating before the reverse torque limiter cam (the cam composed of the inclined surface 4ab and the inclined surface 5b) starts operating. That is, the gap (the size of the gap) between the cam surface K1 and the cam surface T1 is smaller than the gap (the size of the gap) between the inclined surface 4ab and the inclined surface 5b, and the reverse torque transmission cam can start operating before the reverse torque limiter cam starts operating.

[0137] In addition, the power transmission device according to the present embodiment includes: a torque transmission portion formed in each of the first clutch member 4a and the second clutch member 4b, and capable of transmitting the rotational force that has been transmitted to the second clutch member 4b to the first clutch member 4a without using the reverse torque transmission cam (the cam surface K1 and the cam surface T1); and a movement amount limiting portion formed in each of the first clutch member 4a and the second clutch member 4b, and limiting the movement amount of the second clutch member 4b due to the reverse torque transmission cam (the cam surface K1 and the cam surface T1).

[0138] That is, as Figure 6 and Figure 9 shown, a plurality of (three in the present embodiment) protrusions F are integrally formed in the first clutch member 4a so as to be arranged at regular intervals in the circumferential direction. As Figure 7 and Figure 9 shown, the inwardly extending protrusion G is integrally formed in the second clutch member 4b. As Figure 15 and Figure 16 shown, when the first clutch member 4a and the second clutch member 4b are assembled together, one protrusion F is placed between two protrusions G, one side surface F1 of the protrusion F and the contact surface (the first contact surface G1) of one of the protrusions G face each other, and the other side surface F2 of the protrusion F and the contact surface (the second contact surface G2) of the other protrusion G face each other.

[0139] One side surface F1 of the protrusion F formed in the first clutch member 4a and the first contact surface G1 of the protrusion G formed in the second clutch member 4b constitute the torque transmission portion according to the present embodiment. That is, as Figure 15 shown, when the pressure member 5 moves to the working position to press the driving-side clutch disc 6 and the driven-side clutch disc 7 against each other and engage the clutch (transmit driving force), the wall surface K2 of the groove portion K and the wall surface T2 of the protrusion T of the reverse torque transmission cam remain separated (see Figure 17 ), one side surface F1 of the protrusion F and the first contact surface G1 of the protrusion G come into contact with each other, and the rotational force of the second clutch member 4b can be received and transmitted to the first clutch member 4a.

[0140] The other side surface F2 of the protrusion F formed in the first clutch member 4a and the second contact surface G2 of the other protrusion G formed in the second clutch member 4b constitute the movement amount limiting portion according to the present embodiment. That is, when a rotational force is input to the first clutch member 4a via the output shaft 3, the first clutch member 4a and the second clutch member 4b rotate relative to each other. Therefore, the second clutch member 4b moves due to the cam action of the cam surface K1 of the groove portion K and the cam surface T1 of the protrusion T of the reverse torque transmission cam (see Figure 18 ). When the movement amount reaches the set value, as Figure 16 shown, the other side surface F2 of the protrusion F and the second contact surface G2 of the protrusion G come into contact with each other, and the rotation of the second clutch member 4b relative to the first clutch member 4a is restricted. Therefore, when the reverse torque transmission cam operates, the movement amount of the second clutch member 4b can be restricted.

[0141] In the present embodiment, the protrusion F is formed in the first clutch member 4a, and the protrusion G is formed in the second clutch member 4b. Alternatively, the protrusion G may be formed in the first clutch member 4a, and the protrusion F may be formed in the second clutch member 4b. In this case, one side surface F1 of the protrusion F formed in the second clutch member 4b and the first contact surface G1 of one protrusion G formed in the first clutch member 4a constitute the torque transmission portion according to the present embodiment. The other side surface F2 of the protrusion F formed in the second clutch member 4b and the second contact surface G2 of the other protrusion G formed in the first clutch member 4a constitute the movement amount limiting portion according to the present embodiment.

[0142] Next, the function of the reverse torque transmission cam in the present embodiment will be described.

[0143] As Figure 2As shown, when the engine stops or idles, since the driving force of the engine is not transmitted to the input gear 1 or the rotational speed of the input gear 1 is low, the counterweight member 8 is in the radially inner position and the pressure member 5 is in the non-operating position. At this time, when a rotational force is input to the first clutch member 4a via the output shaft 3 (output member), due to the cam action of the reverse torque transmission cam, the second clutch member 4b moves to the right in the figure, and the driving-side clutch plate 6 and the driven-side clutch plate 7 are pressed against each other to transmit the rotational force to the engine side.

[0144] When the vehicle starts to move after having stopped or idled, the rotational speed of the input gear 1 changes from a low speed to a high speed (intermediate speed range), the counterweight member 8 is located between the radially inner position and the radially outer position, and the pressure member 5 is in the operating position. At this time, when a rotational force is input to the first clutch member 4a via the output shaft 3 (output member), for example, when the accelerator pedal is released on a downhill slope, due to the cam action of the reverse torque transmission cam, the second clutch member 4b moves to the right in the figure, and the driving-side clutch plate 6 and the driven-side clutch plate 7 are pressed against each other to transmit the rotational force to the engine side.

[0145] After the vehicle starts, when the vehicle accelerates and travels in the high-speed range, since the rotational speed of the input gear 1 is high, the counterweight member 8 is in the radially outer position and the pressure member 5 is in the operating position. At this time, when a rotational force is input to the first clutch member 4a via the output shaft 3 (output member) in response to a downshift or the like, due to the cam action of the reverse torque transmission cam, the second clutch member 4b moves to the right in the figure, and the driving-side clutch plate 6 and the driven-side clutch plate 7 are pressed against each other to transmit the rotational force to the engine side.

[0146] Here, in the power transmission device according to the present embodiment, the set load of the clutch spring 11 is set to be less than the maximum load of the release spring m. Therefore, when the rotational speed of the engine increases and the counterweight member 8 moves from the radially inner position to the radially outer position, during the process in which the linkage member 9 is pressed and moved by the counterweight member 8, when the release spring m is compressed and exceeds the set load of the clutch spring 11, the clutch spring 11 starts to be compressed, and thus the occurrence of a dead zone can be avoided.

[0147] Subsequently, the function of the power transmission device of the present embodiment will be described in comparison with an existing power transmission device in which the set load of the clutch spring is set to be greater than the maximum load of the release spring.

[0148] First, reference will be made to Figure 34The function of the existing power transmission device is described by a graph (a graph showing the amount of movement (mm) of the linkage member 9 along the horizontal axis and the pressing load (N) generated along the vertical axis in the linkage member 9). In Figure 34 In the graph, P1 represents the pressing load of the linkage member 9 when the deformation amount (compression amount) of the release spring m is the largest (when the maximum load of the release spring m is reached), and P2 represents the pressing load of the linkage member 9 when the clutch spring 11 starts to deform (when the set load of the clutch spring 11 is reached).

[0149] During the process in which the engine speed increases and the counterweight member 8 moves from the radially inner position to the radially outer position to move the linkage member 9, the release spring m deforms and the clutch spring 11 does not deform (i.e., the linkage member 9 and the pressure member 5 move together) until the movement amount of the linkage member 9 reaches α1. And when the movement amount of the linkage member 9 reaches α1, although the pressing load (N) increases from P1 to P2, the linkage member 9 stops moving and becomes a dead zone.

[0150] When the pressing load (N) reaches P2 (the set load of the clutch spring 11) from this state, the clutch spring 11 starts to deform, and the pressing load (N) increases as the linkage member 9 moves. Therefore, the linkage member 9 and the pressure member 5 stop until the pressing load (N) reaches P2 from P1, and after the pressing load (N) has reached P2, the clutch spring 11 starts to be compressed, the clutch plates (the driving-side clutch plate 6 and the driven-side clutch plate 7) are pressed against each other to transmit power, and thus a sense of unexpectedness is generated when power is transmitted.

[0151] On the contrary, in the present embodiment, the set load P2 of the clutch spring 11 is set to be less than the maximum load P1 of the release spring m. Therefore, as Figure 22 shown, during the movement of the linkage member 9, the release spring m is compressed and deformed, and when the movement amount of the linkage member 9 reaches α2, the release spring m reaches the set load P2 of the clutch spring 11, and the clutch spring 11 starts to be compressed (deformed). Subsequently, when the movement amount of the linkage member 9 reaches α1, the release spring m reaches the maximum load P1, and when the release spring m stops being further compressed (deformed), the clutch spring 11 is compressed and deformed, so the linkage member 9 moves continuously.

[0152] That is, according to this figure, during the process in which the rotational speed of the engine increases and the counterweight member 8 moves from the radially inner position to the radially outer position, thereby causing the linkage member 9 to move, the release spring m is continuously compressed (deformed) until the movement amount of the linkage member 9 reaches α2. And when the movement amount of the linkage member 9 becomes α2 and the pressing load (N) reaches the set load P2 of the clutch spring 11, the clutch spring 11 starts to deform together with the release spring m. Subsequently, when the movement amount of the linkage member 9 reaches α1, the release spring m reaches the maximum load P1 and stops deforming, and the clutch spring 11 continues to deform (be compressed), so the linkage member 9 moves continuously.

[0153] Therefore, before the movement amount of the linkage member 9 becomes α1 (before the pressing load becomes P1), only the release spring m deforms until the movement amount of the linkage member 9 becomes α2, and both the release spring m and the clutch spring 11 deform until the movement amount of the linkage member 9 becomes α1, so the linkage member 9 moves continuously. When the movement amount of the linkage member 9 becomes α1 and the pressing load reaches the maximum load P1 of the release spring, the release spring m stops deforming, and the clutch spring 11 continues to deform, thereby allowing the linkage member 9 to move continuously. Therefore, the existing dead zone can be reduced and the counterweight member 8 and the linkage member 9 can move smoothly and continuously, so the impact during clutch engagement can be suppressed and the unexpected feeling during power transmission can be suppressed.

[0154] This embodiment does not have a spring or the like between the first clutch member 4a and the second clutch member 4b. However, for example, a buffer member 12 can be provided between the first clutch member 4a and the second clutch member 4b. In this case, the buffer member 12 is placed between the first clutch member 4a and the second clutch member 4b, and can be compressed (spring deformation) during the process in which the linkage member 9 moves and the pressure member 5 moves from the non-operating position toward the operating position, while applying a driving force and allowing the linkage member 9 and the pressure member 5 to move.

[0155] More specifically, the buffer member 12 is composed of a spring having a set load such that the spring is compressed before the clutch spring 11 starts to be compressed. As Figure 2 、 Figure 3 and Figure 19 shown, the buffer member 12 is assembled by being accommodated in an accommodation recess 4c formed in the surfaces of the first clutch member 4a and the second clutch member 4b facing each other (specifically, the surface of the first clutch member 4a facing the second clutch member 4b).

[0156] The accommodation recess 4c is composed of an annular groove, and the buffer member 12 is composed of a conical disc spring having an annular shape conforming to the shape of the groove. As Figure 19As shown, the receiving recess 4c is formed by a groove having a radially inner wall surface 4ca and a radially outer wall surface 4cb; and a cushioning member 12 formed of an annular spring conforms to the shape of the groove and is fitted into the receiving recess 4c.

[0157] The reverse torque transmission cam according to the present embodiment is formed in a plurality of annular shapes in the surfaces of the first clutch member 4a and the second clutch member 4b facing each other. As Figure 6 shown, the receiving recess 4c is formed in a concentric circle shape at a position adjacent to the reverse torque transmission cam (in the present embodiment, radially inside the position where the reverse torque transmission cam is formed).

[0158] The cushioning member 12 is set to a load (P3) such that the cushioning member 12 is compressed before the clutch spring 11 starts to be compressed. Therefore, as Figure 23 shown, before the movement amount of the linkage member 9 becomes α1 (before the pressing load becomes P1), only the release spring m deforms until the movement amount of the linkage member 9 becomes α2, both the release spring m and the clutch spring 11 deform until the movement amount of the linkage member 9 becomes α3, and subsequently, the release spring m, the clutch spring 11, and the cushioning member 12 all deform until the movement amount of the linkage member 9 becomes α1. Thus, the linkage member 9 moves continuously. When the movement amount of the linkage member 9 becomes α1 and the pressing load reaches the maximum load P1 of the release spring (the maximum load of the cushioning member 12), the release spring m and the cushioning member 12 stop deforming, and the clutch spring 11 continues to deform, thereby allowing the linkage member 9 to move continuously. Therefore, also in this case, the existing dead zone can be reduced and the weight member 8 and the linkage member 9 can move smoothly and continuously, so that the impact at the time of clutch engagement can be suppressed and the unexpected feeling at the time of power transmission can be suppressed.

[0159] In the case where the cushioning member 12 is provided as described above, the receiving recess 4c is formed in a concentric circle shape at a position radially inside the position of the reverse torque transmission cam. However, the receiving recess 4c may be formed in a concentric circle shape at a position radially outside the position of the reverse torque transmission cam. In this case, as Figure 24 shown, the cushioning member 12 may be configured to apply a boosting force in the direction in which the driving side clutch disc 6 and the driven side clutch disc 7 are pressed against each other to the portion (disc pack) where the driving side clutch disc 6 and the driven side clutch disc 7 are stacked.

[0160] In the present embodiment, since the set load of the clutch spring 11 is set to be smaller than the maximum load of the release spring m, the compression of the release spring m and the compression of the clutch spring 11 are continuously performed, and the linkage member 9 moves continuously. Therefore, the occurrence of the dead zone can be avoided and the operability can be improved by suppressing the unexpected feeling at the time of power transmission.

[0161] In the case where the power transmission device includes the buffer member 12, the buffer member 12 can be compressed during the movement of the linkage member 9 and the movement of the pressure member 5 from the non-operating position toward the operating position, thereby applying an urging force while allowing the linkage member 9 and the pressure member 5 to move. When the buffer member 12 or the clutch spring 11 is compressed during the compression release of the spring m, a dead zone can be avoided, and the unexpected feeling during power transmission can be further suppressed, and the operability can be improved. In addition, in the case where the buffer member 12 is provided, since the buffer member 12 is composed of a spring having a set load that causes the spring to be compressed before the clutch spring 11 starts to be compressed, the unexpected feeling during power transmission can be more reliably suppressed.

[0162] In addition, in the case where the buffer member 12 is provided, the buffer member 12 is accommodated in the accommodation recess 4c formed in the surfaces of the first clutch member 4a and the second clutch member 4b facing each other. Therefore, displacement of the position of the buffer member 12 that may occur in the case of the buffer member 12 can be avoided when the first clutch member 4a moves relative to the second clutch member 4b. The accommodation recess 4c is formed in the surface of the first clutch member 4a facing the second clutch member 4b. However, the accommodation recess 4c may be formed in the surface of the second clutch member 4b facing the first clutch member 4a.

[0163] In addition, the above-mentioned accommodation recess 4c is composed of an annular groove, and the buffer member 12 is composed of a spring having an annular shape conforming to the shape of the groove. Therefore, the urging force generated by the buffer member 12 can be applied to the second clutch member 4b and the like substantially uniformly, and the urging force can be applied stably. The reverse torque transmission cam is formed in a plurality of annular shapes in the surfaces of the first clutch member 4a and the second clutch member 4b facing each other, and the accommodation recess 4c is formed in a concentric circle shape at a position adjacent to the reverse torque transmission cam. Therefore, the reverse torque transmission cam can move the second clutch member 4b reliably and stably, and the buffer member 12 can apply the urging force reliably and stably.

[0164] In addition, the bearing holding member C according to the present embodiment is composed of a cylindrical member having one end open, and the open end Ca is assembled and attached to the recess 4d formed in the clutch member (the first clutch member 4a) (attached in a socket joint state). Therefore, it is easy to assemble the bearing holding member C, and the bearing holding member C can be operated stably when performing a shift operation.

[0165] The power transmission device includes: a release spring m that can apply a driving force to the pressure member 5 while allowing the linkage member 9 and the pressure member 5 to move until the driving-side clutch plate 6 and the driven-side clutch plate 7 reach an engaged state before the driving-side clutch plate 6 and the driven-side clutch plate 7 press against each other; and the release spring m is attached to both the bearing holding member C and the pressure member 5, applies a driving force to the pressure member 5, and can apply a driving force to the bearing holding member C to transmit the driving force to the actuating member 10. Therefore, the release spring m can also be used as a spring to prevent play in the shift operation device and reduce the number of components.

[0166] In addition, the release spring m according to the present embodiment is constituted by a conical disc spring that can generate a driving force due to the displacement between the intermediate portion ma and the peripheral portion mb. The intermediate portion ma is attached to the bearing holding member C, and the peripheral portion mb is attached to the pressure member 5. Therefore, the driving force of the release spring m can be stably applied to both the bearing holding member C and the pressure member 5.

[0167] In addition, the clutch member according to the present embodiment includes: a first clutch member 4a coupled to the output shaft 3 (output member); a second clutch member 4b to which the driven-side clutch plate 7 is attached; and a reverse torque transmission cam that can press the driving-side clutch plate 6 and the driven-side clutch plate 7 against each other by moving the second clutch member 4b when a rotational force is input to the first clutch member 4a via the output shaft 3 (output member); and a recess 4d is formed in the first clutch member 4a. Therefore, it is possible to prevent the bearing holding member C from interfering with the movement of the second clutch member 4b due to the reverse torque transmission cam, and it is possible to enable the reverse torque transmission cam to smoothly move each of the bearing holding member C and the second clutch member 4b.

[0168] Through the above embodiment, the reverse torque transmission cam can move the second clutch member 4b in the direction toward the linkage member 9 to maintain contact between the linkage member 9 and the counterweight member 8. Therefore, the driving-side clutch plate 6 and the driven-side clutch plate 7 can be pressed against each other to transmit the rotational force on the wheel side to the engine side to apply engine braking, and actuation can be stably performed by the counterweight member 8 when applying engine braking.

[0169] The reverse torque transmission cam according to the present embodiment is constituted by cam surfaces (K1, T1) integrally formed in the first clutch member 4a and the second clutch member 4b, respectively, and the cam surfaces (K1, T1) are formed in the mating surfaces of the first clutch member 4a and the second clutch member 4b, respectively. Therefore, the reverse torque transmission cam can reliably and smoothly move the second clutch member 4b.

[0170] In addition, the power transmission device includes a crimping assist cam which is constituted by an inclined surface 4aa of a first clutch member 4a and an inclined surface 5a of a pressure member 5 facing each other, and when the rotational force input to the input gear 1 (input member) becomes transmissible to the output shaft 3 (output member), this crimping assist cam increases the crimping force between the driving-side clutch plate 6 and the driven-side clutch plate 7. Therefore, in addition to the crimping force generated by moving the weight member 8 by centrifugal force, the crimping force generated by the crimping assist cam can also be applied, and the driving-side clutch plate 6 and the driven-side clutch plate 7 can be pressed against each other more smoothly and reliably.

[0171] In addition, the power transmission device includes a reverse torque limiter cam which is constituted by an inclined surface 4ab of a first clutch member 4a and an inclined surface 5b of a pressure member 5 facing each other, and when the rotational speed of the output shaft 3 (output member) exceeds the rotational speed of the input gear 1 (input member) and the clutch member (first clutch member 4a) and the pressure member 5 rotate relative to each other, this reverse torque limiter cam can release the crimping force between the driving-side clutch plate 6 and the driven-side clutch plate 7. Therefore, when the weight member 8 is in the radially outer position, excessive driving force transmitted to the engine side via the input gear 1 can be avoided, and the reverse torque transmission cam can be actuated reliably because the reverse torque transmission cam is actuated before the reverse torque limiter cam starts to operate.

[0172] In addition, this embodiment includes: a reverse torque transmission cam which can move the second clutch member 4b to press the driving-side clutch plate 6 and the driven-side clutch plate 7 against each other when a rotational force is input to the first clutch member 4a via the output shaft 3 (output member); and a torque transmission portion which is formed in each of the first clutch member 4a and the second clutch member 4b and can transmit the rotational force that has been transmitted to the second clutch member 4b to the first clutch member 4a without using the reverse torque transmission cam (cam surface K1 and cam surface T1). Therefore, engine braking can be applied by pressing the driving-side clutch plate 6 and the driven-side clutch plate 7 against each other to transmit the rotational force on the wheel side to the engine side, and power transmission can be stably performed when the weight member 8 moves to the radially outer position and the pressure member 5 moves to the operating position.

[0173] In addition, the power transmission device includes a movement amount limiting portion which is formed in each of the first clutch member 4a and the second clutch member 4b and limits the movement amount of the second clutch member 4b generated by the reverse torque transmission cam. Therefore, the reverse torque transmission cam can be enabled to move the second clutch member 4b within a set range.

[0174] In addition, a protrusion F is formed in either the first clutch member 4a or the second clutch member 4b. The torque transmission portion is constituted by one side surface F1 of the protrusion F and a first contact surface G1 that receives a rotational force by contacting the one side surface F1, and the movement amount restricting portion is constituted by the other side surface F2 of the protrusion F and a second contact surface G2 that can restrict the movement amount by contacting the other side surface F2. Therefore, the protrusion F can serve as both the torque transmission portion and the movement amount restricting portion at the same time.

[0175] Thus far, the present embodiment has been described. However, the present invention is not limited to these. For example, as Figure 25 and Figure 26 shown, the present invention can be applied to a power transmission device in which a weight member 8 is movably provided in a housing portion 2a of a clutch housing 2. Similar to the above-described embodiment, the power transmission device includes a first clutch member 4a, a second clutch member 4b, a reverse torque transmission cam, and a buffer member 12 disposed between the first clutch member 4a and the second clutch member 4b.

[0176] Figure 25 An embodiment is shown in which the buffer member 12 is attached to a surface of the first clutch member 4a facing the second clutch member 4b. Figure 26 An embodiment is shown in which the buffer member 12 attached to a portion (disc group) where a driving-side clutch disc 6 and a driven-side clutch disc 7 of the first clutch member 4a are stacked and to which an actuating force is applied is attached to this surface. The bearing holding member C' can be moved by an actuating member 10', and a release spring m' is constituted by a coil spring attached to both the bearing holding member C' and the pressure member 5.

[0177] In addition, instead of the buffer member 12 constituted by a conical disc spring, another elastic member can be used. For example, as Figure 27 shown, a buffer member 12' constituted by a wave spring can be provided in a receiving recess 4c. As Figure 28 and Figure 29 shown, the wave spring is constituted by a C-shaped member that has a cutout portion 12'a in a part of a ring, the wave spring has a wave shape with respect to a thickness direction t, and can generate an elastic force. The wave spring is disposed between the first clutch member 4a and the second clutch member 4b, and the wave spring can apply an actuating force while allowing the linkage member 9 and the pressure member 5 to move by being compressed during the process in which the linkage member 9 moves and the pressure member 5 moves from a non-operating position toward an operating position.

[0178] In the power transmission device shown in the figure, the bearing holding member C has a plurality of (three in the present embodiment) communication holes Cc formed in its side wall, and allows the oil supplied to the inside of the bearing holding member C to flow to the outside via the oil flow path r. The actuating member 10" engages with the roller bearing B1 of the bearing holding member C, and due to the operation of the driver or the actuator, the actuating member 10" can move the pressure member 5 between the working position and the non-working position by moving in the left-right direction in the figure.

[0179] As Figure 27 shown, the actuating member 10" according to the present embodiment is a pull type. When operated by hand or an actuator, the actuating member 10" moves to the right in the figure and pulls the bearing B1 in the same direction, and thereby the actuating member 10" can release the pressing force between the driving side clutch plate 6 and the driven side clutch plate 7. As Figure 30 shown, a buffer member 12' composed of a conical disc spring can be used instead of Figure 27 the buffer member 12 of the power transmission device shown.

[0180] In addition, as Figure 31 shown, reverse torque transmission cams (cam surfaces K1 and cam surfaces T1) can be provided in the outer peripheral portions of each of the first clutch member 4a and the second clutch member 4b. With this power transmission device, since the reverse torque transmission cams are provided in the outer peripheral portions of each of the first clutch member 4a and the second clutch member 4b, the action of the cams can be enhanced, and the moving force (thrust force) of the second clutch member 4b can be set to be larger.

[0181] In Figure 31 the power transmission device shown, no buffer member 12 or 12' is provided. However, a buffer member 12 composed of a conical disc spring can be provided radially inside the reverse torque transmission cams (cam surfaces K1 and cam surfaces T1) (see Figure 32 ), or a buffer member 12' composed of a wave spring can be provided radially inside the reverse torque transmission cams (cam surfaces K1 and cam surfaces T1) (see Figure 33 ).

[0182] In the present embodiment, the bearing holding member C is constituted by a cylindrical member having one end open, and the open end portion Ca is fitted and attached to a recess 4d formed in the clutch member (first clutch member 4a). However, a bearing holding member having another shape may be used, and an attachment structure different from the configuration (so-called socket joint) in which the bearing holding member is fitted into the recess formed in the clutch member may be used. Note that the power transmission device according to the present invention can be applied to various multi-disc clutch power transmission devices in addition to motorcycles, automobiles, three- or four-wheel ATVs, general-purpose machines, and the like.

[0183] Industrial applicability

[0184] The present invention can be applied to power transmission devices having different external shapes or having another additional function as long as the set load of the clutch spring is set to be less than the maximum load of the release spring.

Claims

1. A power transmission device, the power transmission device comprises: a clutch member accommodated in a clutch housing which rotates together with an input member that rotates by the driving force of an engine of a vehicle, and a plurality of driving-side clutch plates are attached to the clutch housing, a plurality of driven-side clutch plates formed alternately with the driving-side clutch plates of the clutch housing are attached to the clutch member, and the clutch member is coupled to an output member capable of rotating the wheels of the vehicle; a pressure member capable of moving between a working position and a non-working position, in the working position, the pressure member presses the driving-side clutch plate and the driven-side clutch plate against each other to be able to transmit the driving force of the engine to the wheels, in the non-working position, the pressure member releases the pressing force between the driving-side clutch plate and the driven-side clutch plate to be able to stop transmitting the driving force of the engine to the wheels, characterized in that the clutch member has: a first clutch member coupled to the output member; a second clutch member to which the driven-side clutch plates are attached; a reverse torque transmission cam which, when a rotational force is input to the first clutch member via the output member, can move the second clutch member to press the driving-side clutch plate against the driven-side clutch plate; and a torque transmission portion respectively formed on the first clutch member and the second clutch member, capable of transmitting the rotational force transmitted to the second clutch member to the first clutch member without passing through the reverse torque transmission cam, the torque transmission portion is located at a position radially inside the driving-side clutch plate and the driven-side clutch plate.

2. The power transmission device according to claim 1, wherein the torque transmission portion is located at a position radially inside the reverse torque transmission cam.

3. The power transmission device according to claim 1, wherein the torque transmission portion has a protrusion formed on the inner peripheral surface of the second clutch member.

4. The power transmission device according to claim 3, wherein the protrusion protrudes radially inward from the inner peripheral surface of the second clutch member.

5. The power transmission device according to claim 3, wherein the first clutch member has an insertion hole at its center for inserting the output member, when the direction in which the output member extends is defined as the axial direction, the protrusion has a thickness in the axial direction.

6. The power transmission device according to claim 4, wherein the second clutch member has spline fitting teeth protruding radially outward from the outer peripheral surface of the second clutch member, and the driven-side clutch plates are attached to the spline fitting teeth, the radial length of the protrusion is longer than the radial length of the spline fitting teeth.

7. The power transmission device according to claim 1, wherein when viewed in the radial direction of the output member, the reverse torque transmission cam and the torque transmission portion do not overlap.

8. The power transmission device according to claim 1, wherein, when the direction in which the output member extends is defined as the axial direction, with respect to the axial direction, the reverse torque transmission cam is located between the input member and the drive-side clutch plate.

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