Power transmission device

Abstract

The present invention provides a power transmission device comprising a centrifugal clutch means equipped with a pressure contact member that presses a drive-side clutch plate and a driven-side clutch plate together as a weight member moves from an inner diameter side position to an outer diameter side position, wherein in a cross section along the axis of the output member, a straight line passing through the pressure contact member and parallel to the axis passes through the pressure contact surface between the drive-side clutch plate and the driven-side clutch plate. [Solution] The centrifugal clutch means 9 is equipped with a pressure contact member 12 that moves in the stacking direction of the drive clutch plate 6 and the driven clutch plate 7 and presses them together as the weight member 10 moves from the inner diameter side position to the outer diameter side position, and in a cross section along the axis of the output shaft 3, a straight line passing through the pressure contact member 12 and parallel to the axis passes through the pressure contact surface of the drive clutch plate 6 and the driven clutch plate 7.

Description

Technical Field

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

Background Art

[0002] Generally, a power transmission device provided in a motorcycle is for arbitrarily transmitting or blocking the driving force of an engine to a transmission and a driving wheel. It has an input member connected to the engine side, an output member connected to the transmission and driving wheel sides, a clutch member connected to the output member, and a pressure member that can approach or separate from the clutch member. By bringing the pressure member close to the clutch member, the driving-side clutch plate and the driven-side clutch plate are pressed together to transmit power, and by separating the pressure member from the clutch member, the pressing force between the driving-side clutch plate and the driven-side clutch plate is released to block the transmission of the power.

[0003] As a conventional power transmission device, for example, as disclosed in Patent Document 1, a centrifugal clutch means having a weight member that moves from the inner diameter side position to the outer diameter side position of the groove portion by centrifugal force accompanying the rotation of the clutch housing is proposed. According to such a conventional power transmission device, when the clutch housing rotates with the driving of the engine, centrifugal force can be applied to the weight member, and the driving-side clutch plate and the driven-side clutch plate can be pressed together to transmit the driving force of the engine to the wheels.

[0004] Further, according to the above conventional power transmission device, since a cam for pressing assist for increasing the pressing force between the driving-side clutch plate and the driven-side clutch plate is provided when the rotational force input to the input member can be transmitted to the output member, when the driver operates the clutch to press the driving-side clutch plate and the driven-side clutch plate together, the operating force can be reduced to perform smooth power transmission. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2013 / 183588 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The applicant's objective was to provide a power transmission device comprising a centrifugal clutch means equipped with a pressure contact member that presses the drive-side clutch plate and the driven-side clutch plate together as the weight member moves from an inner diameter side position to an outer diameter side position, wherein in a cross-section along the axis of the output member, a straight line passing through the pressure contact member and parallel to the axis passes through the pressure contact surface between the drive-side clutch plate and the driven-side clutch plate. [Means for solving the problem]

[0007] The invention described in claim 1 is a clutch member that rotates together with an input member that rotates with the driving force of a vehicle engine and is housed in a clutch housing to which a plurality of drive-side clutch plates are attached, wherein a plurality of driven-side clutch plates are attached alternately with the drive-side clutch plates and the clutch member is connected to an output member capable of rotating the wheels of the vehicle, and the clutch member has an operating position that presses the drive-side clutch plates and the driven-side clutch plates together to enable the transmission of the engine's driving force to the wheels, and releases the pressing force between the drive-side clutch plates and the driven-side clutch plates. The clutch housing comprises a pressure member that can move between a non-operating position and a non-operating position that can block the transmission of the engine's driving force to the wheels, and a weight member that can move from an inner diameter position to an outer diameter position due to the centrifugal force accompanying the rotation of the clutch housing, wherein when the weight member is in the outer diameter position, it presses the drive-side clutch plate and the driven-side clutch plate together, making it possible to transmit the engine's driving force to the wheels, and when the weight member is in the inner diameter position, it releases the pressure between the drive-side clutch plate and the driven-side clutch plate, thereby transmitting the engine's driving force A power transmission device comprising a centrifugal clutch means capable of blocking the transmission of power to the wheel, wherein the centrifugal clutch means includes a pressure contact member that moves in the stacking direction of the drive-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 drive-side clutch plate and the driven-side clutch plate into contact, and the pressure contact member is positioned between the weight member and the drive-side clutch plate and the driven-side clutch plate in the axial direction of the output member, and guides the movement of the weight member and the wheel The output member is configured to have an inclined surface that moves the contact member in the stacking direction of the drive clutch plate and the driven clutch plate when the thread member moves from the inner diameter side position to the outer diameter side position, an annular main body portion, and a claw portion that protrudes radially outward from the outer circumferential surface of the main body portion, and in a cross section along the axis of the output member, there exists a straight line that passes through the contact surfaces of the drive clutch plate and the driven clutch plate and the inclined surface of the contact member and is parallel to the axis, and furthermore, the side surface of the main body portion in the stacking direction of the drive clutch plate and the driven clutch plate isThe area from the inner edge of the drive-side clutch plate to the outer edge of the driven-side clutch plate in the axial cross-section of the output member is formed as a flat plane over its entire circumference.

[0008] The invention described in claim 2 is a power transmission device according to claim 1, wherein the centrifugal clutch means comprises a holding member that holds the weight member so as to be movable between the inner diameter side position and the outer diameter side position, the pressure contact member is configured to be independently able to move closer to or further away from the holding member, and the holding member has a plurality of housing portions for housing the weight member, a rib portion located between the plurality of housing portions, and a claw portion located radially outward of the rib portion and attached to the clutch housing.

[0009] The invention described in claim 3 is a power transmission device according to claim 2, wherein the surface of the rib portion on the side of the pressure-welding member and the surface of the claw portion on the side of the pressure-welding member are formed flush with each other. [Effects of the Invention]

[0010] According to the present invention, a centrifugal clutch means is provided which includes a pressure contact member that presses the drive-side clutch plate and the driven-side clutch plate together as the weight member moves from an inner diameter side position to an outer diameter side position, and in a cross section along the axis of the output member, a straight line exists that passes through the pressure contact surfaces of the drive-side clutch plate and the driven-side clutch plate and the inclined surface of the pressure contact member, and is parallel to the axis. [Brief explanation of the drawing]

[0011] [Figure 1] External view showing a power transmission device according to an embodiment of the present invention. [Figure 2] Cross-sectional view along line II-II in Figure 1 [Figure 3] Sectional view along line III-III in Figure 1 [Figure 4] Perspective view showing the clutch housing in the power transmission system. [Figure 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 - broken 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] Schematic diagram for explaining (a) the action of the cam for pressure - contact assist and (b) the action of the cam for back - torque limiter in the power transmission device [Figure 21] Schematic diagram showing the vehicle to which the power transmission device is applied [Figure 22] Cross - sectional view showing the state where the weight member in the power transmission device is at the inner - diameter side position [Figure 23] Cross - sectional view showing the state where the weight member in the power transmission device is at the intermediate position between the inner - diameter side position and the outer - diameter side position [Figure 24]Cross-sectional view showing the state in which the weight member of the power transmission device is located on the outer diameter side. [Figure 25] This cross-sectional view shows the state in which the weight member of the power transmission device is in the outer diameter position and the pressure member is in the non-operating position. [Figure 26] This graph shows the relationship between engine speed and torque / assist cam position in the power transmission system according to this embodiment. [Figure 27] A graph showing the relationship between engine speed and torque / assist cam position in a conventional power transmission system. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. As shown in Figure 21, the power transmission device K according to this embodiment is installed in a vehicle and is used to arbitrarily transmit or interrupt the driving force of the engine E to the drive wheels T via the transmission M. As shown in Figures 1 to 17, it is configured to include a clutch housing 2 on which an input gear 1 (input member) that rotates with the driving force of the vehicle's engine E is formed, an output shaft 3 (output member) connected to the transmission M, a clutch member (first clutch member 4a and second clutch member 4b), a pressure member 5, a plurality of drive-side clutch plates 6 and a plurality of driven-side clutch plates 7, a centrifugal clutch means 9 equipped with a weight member 10, and an auxiliary clutch plate 17.

[0013] The input gear 1 is designed to rotate around the output shaft 3 when a 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 consists of a cylindrical member with an open end on the right side in Figures 2 and 3, and is connected to the input gear 1, so that it can rotate together with the rotation of the input gear 1 due to the driving force of the engine E.

[0014] Furthermore, as shown in Figure 4, the clutch housing 2 has a plurality of notches 2a formed in the circumferential direction, and a plurality of drive-side clutch plates 6 are attached by fitting into these notches 2a. Each of these drive-side clutch plates 6 is made of a plate material formed in a substantially annular shape and is configured to rotate with the rotation of the clutch housing 2 and to slide in the axial direction (left-right direction in Figures 2 and 3).

[0015] The clutch members (first clutch member 4a and second clutch member 4b) are attached to a plurality of driven clutch plates 7 which are alternately formed with the drive-side clutch plate 6 of the clutch housing 2, and are connected to an output shaft 3 (output member) that can rotate the drive wheel T via the vehicle's transmission M, and are composed of two members, the first clutch member 4a and the second clutch member 4b, assembled together.

[0016] The first clutch member 4a is configured such that the output shaft 3 is inserted through an insertion hole (see Figures 5 and 6) formed in its center, and the gears formed on it mesh together to connect in the rotational direction. As shown in Figures 5 and 6, the first clutch member 4a has a tapered surface 4aa that constitutes a pressure assist cam and a tapered surface 4ab that constitutes a back torque limiter cam. In the same figures, reference numeral 4ac indicates a boss portion in which an insertion hole for a bolt B for connecting the first clutch member 4a and the fixing member 8 is formed.

[0017] As shown in Figures 7 and 8, the second clutch member 4b consists of an annular member with a flange portion 4bb formed thereon, and the driven clutch plate 7 is attached to the spline fitting portion 4ba formed on its outer circumference by spline fitting. 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 multiple drive-side clutch plates 6 and driven-side clutch plates 7 are attached alternately in a stacked state between the flange portion 5c of the pressure member 5 and the flange portion 4bb of the second clutch member 4b.

[0018] As shown in Figures 9 and 10, the pressure member 5 is a disc-shaped member with a flange portion 5c formed along its peripheral edge, and is movable between an operating position in which the drive-side clutch plate 6 and the driven-side clutch plate 7 are pressed together to enable the transmission of the engine E's driving force to the wheels, and a non-operating position in which the pressing force between the drive-side clutch plate 6 and the driven-side clutch plate 7 is released, thereby blocking the transmission of the engine E's driving force to the wheels.

[0019] More specifically, the spline fitting portion 4ba formed on the second clutch member 4b is configured as an integrally formed uneven shape over substantially the entire circumference of the outer peripheral side surface of the second clutch member 4b, as shown in Figures 7 and 8. The driven clutch plate 7 is fitted into the grooves constituting the spline fitting portion 4ba, thereby restricting rotational movement of the driven clutch plate 7 while allowing axial movement of the driven clutch plate 7 relative to the second clutch member 4b, and enabling it to rotate together with the second clutch member 4b.

[0020] The driven clutch plates 7 are stacked alternately with the driving clutch plates 6, and adjacent clutch plates 6 and 7 can be pressed together or released from their pressing force. That is, both clutch plates 6 and 7 are allowed to slide axially with respect to the second clutch member 4b. When the clutch plates (6a, 6b, 7a, 7b) are pressed together 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. 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 transmission of rotational force to the output shaft 3 ceases.

[0021] However, when the drive-side clutch plate 6 and the driven-side clutch plate 7 are pressed together, the rotational force (driving force of the engine E) input to the clutch housing 2 is transmitted to the drive wheel side (transmission M) via the output shaft 3 (output member), and when the pressure contact between the drive-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.

[0022] Furthermore, as shown in Figures 9 and 10, the pressure member 5 has multiple (three in this embodiment) insertion holes 5d formed around its circumference, and a clutch spring S is inserted into each insertion hole 5d. As shown in Figure 2, one end of the clutch spring S is housed within the insertion hole 5d and in contact with the fixing member 8, biasing it in a direction that presses the drive-side clutch plate 6 and the driven-side clutch plate 7 into contact. By operating a clutch operating means (not shown), the drive-side clutch plate 6 and the driven-side clutch plate 7 can be pressed into or released from contact.

[0023] Furthermore, in this embodiment, as shown in Figures 5, 6, 9, and 10, the first clutch member 4a has inclined surfaces 4aa and 4ab, while the pressure member 5 has inclined surfaces 5a and 5b that are opposite to these inclined surfaces 4aa and 4ab. That is, inclined surface 4aa and inclined surface 5a come into contact to form a pressure assist cam, and inclined surface 4ab and inclined surface 5b come into contact to form a back torque limiter cam.

[0024] Then, when the rotational speed of the engine E increases and the rotational force input to the input gear 1 and clutch housing 2 can be transmitted to the output shaft 3 via the first clutch member 4a and the second clutch member 4b (with the weight member 10 in the outer diameter position), as shown in Figure 20(a), a rotational force in direction a is applied to the pressure member 5. As a result, the action of the pressure assist cam generates a force in direction c in the same figure on the pressure member 5. Consequently, the flange portion 5c of the pressure member 5 moves in a direction that brings it closer to the flange portion 4bb of the second clutch member 4b (to the left in Figures 2 and 3), thereby increasing the pressure between the drive-side clutch plate 6 and the driven-side clutch plate 7.

[0025] On the other hand, when the rotation of the output shaft 3 exceeds the rotational speed of the input gear 1 and clutch housing 2, resulting in back torque, a rotational force in the direction b is applied to the clutch member 4, as shown in Figure 20(b). As a result, the back torque limiter cam moves the pressure member 5 in the direction d in the same figure, releasing the contact force between the drive-side clutch plate 6 and the driven-side clutch plate 7. This prevents malfunctions in the power transmission device K and power source (engine E side) caused by back torque.

[0026] As shown in Figures 11 to 19, the centrifugal clutch mechanism 9 includes a weight member 10 that is movable from an inner diameter position (see Figure 18) to an outer diameter 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 position, it presses the drive-side clutch plate 6 and the driven-side clutch plate 7 together, enabling the driving force of the engine E to be transmitted to the wheels (drive wheels T). When the weight member 10 is in the inner diameter position, it releases the pressure between the drive-side clutch plate 6 and the driven-side clutch plate 7, thereby blocking the transmission of the driving force of the engine E to the wheels (drive wheels T).

[0027] Specifically, the centrifugal clutch mechanism 9 is composed of a weight member 10 made of a spindle-shaped member, a holding member 11 to which a support member 13 is attached, a pressure contact member 12, a first spherical member 14, a second spherical member 15, and a biasing member 16 made of a coil spring. The holding member 11 and the pressure contact member 12 have multiple protrusions formed in the circumferential direction and are fitted into the notch 2a of the clutch housing 2, similar to the drive-side clutch plate 6. As a result, the holding member 11 and the pressure contact member 12 are each movable in the axial direction of the clutch housing 2 and are also engaged in the rotational direction so that they can rotate together with the clutch housing 2.

[0028] As shown in Figure 16, the weight member 10 consists of a piece-shaped member having one face X and the other face Y, and as shown in Figure 16 and Figure 17, it is configured to have a through hole 10a formed from one face X to the other face Y, an insertion portion 10b formed on the other face Y, and a groove 10c formed on one face X. As shown in Figures 18 and 19, the weight member 10 is housed in the housing portion 11a of the holding member 11, and is held in the inner diameter position (see Figure 18) when no centrifugal force is applied, and moves outward against the biasing force of the biasing member 16 when centrifugal force is applied, reaching the outer diameter position (see Figure 19).

[0029] The holding member 11 holds the weight member 10 so that it can move between an inner diameter position and an outer diameter position. As shown in Figure 13, it is made of an annular member and is formed in multiple ways along the circumferential direction. It has a housing portion 11a for housing the weight member 10, a groove shape 11b formed within the housing portion 11a, and a pressing surface 11c. Each housing portion 11a has a concave shape that matches the shape and range of movement of the weight member 10, and is configured so that one end of the biasing member 16 can contact its inner circumferential wall surface 11aa.

[0030] Furthermore, a support member 13 is fixed to the surface of the holding member 11 on which the housing portion 11a is formed. As shown in Figure 14, the support member 13 has a radially formed holding portion 13a, and the weight member 10 is held by the holding member 11 when this holding portion 13a aligns with the groove 10c of the weight member 10. In other words, the weight member 10 has a groove 10c formed at the center of one of its surfaces X in the direction from the inner diameter side to the outer diameter side, and by aligning the holding portion 13a with the groove 10c, the weight member 10 is held so as to be movable in the radial direction (from the inner diameter side to the outer diameter side).

[0031] The pressure contact member 12 moves in the stacking direction (right side in Figures 2 and 3) of the drive clutch plate 6 and the driven clutch plate 7 as the weight member 10 moves from the inner diameter side position to the outer diameter side position, causing the drive clutch plate 6 and the driven clutch plate 7 to press against each other. Specifically, as shown in Figure 15, the pressure contact member 12 is made up of an annular member and has 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.

[0032] 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 stationary, the biasing force of the biasing member 16 holds the weight members 10 in the inner diameter position, 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, so that the contact member 12 moves in a direction away from the holding member 11 (i.e., in a direction that brings the drive-side clutch plate 6 and the driven-side clutch plate 7 into contact).

[0033] However, when the holding member 11 and the pressure contact member 12 are assembled with the weight member 10 in between, as shown in Figures 11 and 12, the gradient grooves 12a are positioned corresponding to each weight member 10. Due to centrifugal force, the weight member 10 moves along the gradient grooves 12a from the inner diameter side to the outer diameter side, causing the pressure contact member 12 to move in the direction of the arrow in Figure 11 (right side in the figure). The pressing surface 12c formed on the pressure contact member 12 presses against the drive-side clutch plate 6 and the driven-side clutch plate 7, creating a pressure contact state. Simultaneously, the holding member 11 moves in the opposite direction to the arrow in Figure 11 (left side in the figure) due to the reaction force, and the pressing surface 11c formed on the holding member 11 presses against the auxiliary clutch plate 17.

[0034] As shown in Figures 18 and 19, the weight member 10 according to this embodiment is housed in multiple housing portions 11a formed circumferentially on the holding member 11, and is movable in the radial direction. Multiple biasing members 16 are arranged circumferentially between the inner circumferential wall surface 11aa (see Figure 13) of the housing portion 11a and the weight member 10 (two at a time in this embodiment), biasing the weight member 10 from the outer diameter side to the inner diameter side. Here, the inner circumferential wall surface 11aa of the housing portion 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.

[0035] Furthermore, the weight member 10 according to this embodiment has a tunnel-shaped insertion portion 10b that allows the biasing member 16 to be inserted and attached while leaving an opening on the surface facing the holding member 11 (the other surface Y in Figure 17). By housing the weight member 10 with the biasing member 16 inserted into the insertion portion 10b in the housing portion 11a of the holding member 11, the biasing member 16 is interposed and attached between the inner circumferential wall surface 11aa of the housing portion 11a and the weight member 10. The biasing member 16 is arranged so that one end abuts against the inner circumferential wall surface 11aa and the other end abuts against the end wall surface 10ba of the insertion portion 10b, so that the weight member 10 can be biased from the outer diameter side to the inner diameter side.

[0036] The first spherical member 14 consists of a steel ball attached to the weight member 10, and as shown in Figures 16 and 17, a portion of it protrudes from one opening 10aa (the smaller diameter opening on the X side) of the through hole 10a formed in the weight member 10, allowing it to roll in contact with the rolling surface of the pressure contact member 12. The second spherical member 15 also consists of a steel ball attached to the weight member 10, and as shown in Figures 16 and 17, a portion of it protrudes from the other opening 10ab (the larger diameter opening on the Y side) of the through hole 10a formed in the weight member 10, allowing it to roll in contact with the rolling surface of the holding member 11.

[0037] As shown in Figure 17, the through hole 10a according to this embodiment is formed in a tapered shape such that the diameter continuously increases from one opening 10aa (a smaller diameter opening on one side X) to the other opening 10ab (a larger diameter opening on the other side Y), and the first spherical member 14 is prevented from coming off at the outer peripheral edge of the smaller diameter opening (in this embodiment, the opening 10aa on one side X) of the two openings 10ab. That is, the first spherical member 14 and the second spherical member 15 according to this embodiment consist of spherical members of different diameters corresponding to the inner diameter of the through hole 10a (the second spherical member 15 is larger in diameter than the first spherical member 14), and the smaller diameter first spherical member 14 is prevented from coming off at the opening edge on the smaller diameter side of the through hole 10a, while being able to roll while in contact with the inner peripheral surface of the through hole 10a.

[0038] On the other hand, as shown in Figures 11 and 12, the second spherical member 15 is prevented from coming off by the rolling surface of the retaining member 11. As a result, the small-diameter first spherical member 14 is prevented from coming off at the small-diameter opening edge of the through hole 10a, while the large-diameter second spherical member 15 is prevented from coming off by the rolling surface of the retaining member 11, with a portion of it protruding from the large-diameter opening of the through hole 10a. In this embodiment, the large-diameter second spherical member 15 is assembled facing the rolling surface of the retaining member 11, but the second spherical member 15 may also be assembled facing the rolling surface of the pressure contact member 12. In this case, the small-diameter first spherical member 14 is prevented from coming off at the small-diameter opening edge of the through hole 10a, while the large-diameter second spherical member 15 is prevented from coming off by the rolling surface of the pressure contact member 12, with a portion of it protruding from the large-diameter opening of the through hole 10a.

[0039] However, the rolling surface of the holding member 11 (the rolling surface of the second spherical member 15 in this embodiment) consists of a groove shape 11b along the direction of movement 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) consists of a groove shape 12b along the direction of movement of the weight member 10 (the direction connecting the inner diameter side position and the outer diameter side position), as shown in Figure 15.

[0040] Furthermore, as shown in Figures 16, 18, and 19, the first spherical member 14 and the second spherical member 15 in this embodiment are each formed in multiple quantities (two of the first spherical member 14 and two of the second spherical member 15 in this embodiment) extending in the circumferential direction of the holding member 11 (width direction of the weight member 10), so that the first spherical member 14 and the second spherical member 15 can move along the groove shapes 11b and 12b while rolling within the through hole 10a as the weight member 10 moves.

[0041] The auxiliary clutch plate 17 is made of an annular member with a different diameter from the drive-side clutch plate 6 and the driven-side clutch plate 7 (in this embodiment, a smaller diameter than the drive-side clutch plate 6 and the driven-side clutch plate 7). As shown in Figures 2 and 3, the output shaft 3 (output member) is inserted through its central opening 17a to create a fitted state, and it has a pressed surface 17b that faces the pressing surface 11c of the holding member 11.

[0042] When the weight member 10 is in the outer diameter position (i.e., when the drive-side clutch plate 6 and the driven-side clutch plate 7 are in contact), the auxiliary clutch plate 17 is pressed against the holding member 11 by the pressing surface 11c formed on the holding member 11, thereby enabling the transmission of the engine E's driving force to the output shaft 3. Furthermore, when the weight member 10 is in the inner diameter position (i.e., when the contact force between the drive-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 contact force is released, thereby preventing the transmission of the engine E's driving force to the output shaft 3.

[0043] In other words, when the weight member 10 moves to the outer diameter side position, the gradient groove 12a functions as a cam, causing the holding member 11 and the contact member 12 to move apart from each other. As a result, the pressing surface 12c of the contact member 12 presses against the drive-side clutch plate 6 and the driven-side clutch plate 7, and the pressing surface 11c of the holding member 11 presses against the pressed surface 17b of the auxiliary clutch plate 17, thereby transmitting the driving force of the engine E to the drive wheels T.

[0044] According to the power transmission device K of this embodiment, the through hole 10a of the weight member 10 in the centrifugal clutch means 9 is tapered from one opening 10aa to the other opening 10ab, and the first spherical member 14 is prevented from coming off at the outer peripheral edge of the smaller diameter opening of the two openings 10ab. As a result, the first spherical member 14 can be easily and accurately attached to the weight member 10, and manufacturing costs can be reduced.

[0045] Furthermore, the first spherical member 14 and the second spherical member 15 are made up of spherical members of different diameters corresponding to the inner diameter of the through hole 10a, and are made capable of rolling while in contact with the inner circumferential surface of the through hole 10a. This allows the first spherical member 14 and the second spherical member 15 to roll stably when the weight member 10 is moved, enabling smooth movement. Moreover, in this embodiment, the second spherical member 15 is prevented from coming off by the rolling surface of the holding member 11 or the pressure contact member 12, making it easy to prevent the first spherical member 14 and the second spherical member 15 from coming off.

[0046] Furthermore, since the rolling surfaces of the holding member 11 or the pressure contact member 12 are groove-shaped (11b, 12b) along the direction of movement of the weight member 10, it is possible to ensure that the second spherical member 15 does not come off on the large-diameter opening side and the first spherical member 14 does not come off on the small-diameter opening side, while also enabling smoother movement of the weight member 10.

[0047] In addition, in this embodiment, the weight members 10 are each housed in multiple housing portions 11a formed circumferentially on the holding member 11, and are movable in the radial direction. Furthermore, multiple biasing members 16 are arranged circumferentially between the inner circumferential wall surface 11aa of the housing portion 11a and the weight members 10, biasing the weight members 10 from the outer diameter side to the inner diameter side. As a result, the weight members 10 can be biased accurately from the outer diameter side to the inner diameter side, and the weight members 10 can be moved stably in response to centrifugal force.

[0048] Furthermore, the weight member 10 according to this embodiment has an insertion portion 10b formed on the surface facing the holding member 11, allowing the biasing member 16 to be inserted and attached, thus making it easy to assemble the biasing member 16 to the weight member 10. Moreover, the weight member 10 according to this embodiment has a groove 10c formed in the direction from the inner diameter side to the outer diameter side, and the holding member 11 (specifically, the support member 13 fixed to and integrated with the holding member 11) has a holding portion 13a formed to match the groove 10c and hold the weight member 10, so that the movement of the weight member 10 can be made stable.

[0049] Furthermore, the centrifugal clutch means 9 according to this embodiment is configured to include a first spherical member 14 that partially protrudes from one opening 10aa of the through hole 10a formed in the weight member 10 and is able to roll in contact with the rolling surface (groove shape 12b) of the pressure contact member 12, and a second spherical member 15 that partially protrudes from the other opening 10ab of the through hole 10a formed in the weight member 10 and is able to roll in contact with the rolling surface (groove shape 11b) of the holding member 11, thereby enabling more stable movement of the weight member 10.

[0050] In particular, the holding member 11 or the pressure contact member 12 has groove shapes (11b, 12b) along the direction of movement of the weight member 10, and these groove shapes (11b, 12b) serve as the rolling surfaces of the first spherical member 14 or the second spherical member 15, thereby enabling smoother movement of the weight member 10. Furthermore, since multiple first spherical members 14 and second spherical members 15 are formed in this embodiment, extending in the circumferential direction of the holding member 11 (the width direction of the weight member 10), even more stable movement of the weight member 10 can be achieved.

[0051] In this embodiment, the power transmission device K is configured to have, as shown in Figure 26, a first torque region α1 that restricts the operation of the pressure-contact assist cam (a cam composed of gradient surfaces 4aa and 5a) and a second torque region α2 that allows the operation of the pressure-contact assist cam, during the process in which the weight member 10 of the centrifugal clutch means 9 moves from the inner diameter side position to the outer diameter side position and the transmission torque from the input gear 1 (input member) to the output shaft 3 (output member) increases.

[0052] Specifically, as shown in Figures 5 and 6, the first clutch member 4a in this embodiment has a contact surface 4ad formed on a part of the surface facing the pressure member 5, and as shown in Figures 9 and 10, the pressure member 5 has a contact surface 5e formed on a part of the surface facing the first clutch member 4a. In the assembled state of the first clutch member 4a, the second clutch member 4b, and the pressure member 5 (a state in which 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, as shown in Figures 2 and 3.

[0053] Thus, in the state where the contact surface 4ad and the contact surface 5e are in contact (the first torque region α1 during the period t1 to t2 in Figure 26), as 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 torque transmitted 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.

[0054] Subsequently, the weight member 10 of the centrifugal clutch mechanism 9 moves further from the intermediate position (see Figure 23) toward the outer diameter side position (see Figure 24), and is pressed against the flange portion 4bb of the second clutch member 4b, causing the drive-side clutch plate 6 and the driven-side clutch plate 7 to come into contact. 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 move axially (to the right in Figures 2 and 3) relative to the first clutch member 4a, causing the contact surface 4ad of the first clutch member 4a and the contact surface 5e of the pressure member 5 to separate. Figure 25 shows the 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).

[0055] Thus, in the state where the contact surface 4ad and the contact surface 5e are separated (second torque region α2 during the period t2 in Figure 26), relative movement between the first clutch member 4a and the pressure member 5 is permitted during the process in which the weight member 10 of the centrifugal clutch means 9 moves from the inner diameter side position to the outer diameter side position and the torque transmitted from the input gear 1 (input member) to the output shaft 3 (output member) increases, so the operation of the pressure assist cam is permitted.

[0056] In other words, in this embodiment, in the first torque region α1, the contact surface 4ad of the first clutch member 4a and the contact surface 5e of the pressure member 5 come into contact, restricting the operation of the pressure assist cam, while in the second torque region α2, the contact surface 4ad of the first clutch member 4a and the contact surface 5e of the pressure member 5 are separated, allowing the operation of the pressure assist cam to proceed.

[0057] Furthermore, in this embodiment, in the first torque region α1, the centrifugal clutch means 9 moves the second clutch member 4b without moving the first clutch member 4a, thereby maintaining the contact state between the first clutch member 4a and the pressure member 5. In the second torque region α2, the centrifugal clutch means 9 moves both the second clutch member 4b and the pressure member 5, thereby separating the contact surface 4ad of the first clutch member 4a from the contact surface 5e of the pressure member 5. In particular, in this embodiment, the centrifugal clutch means 9 transitions from the first torque region α1 to the second torque region α2 during its operation.

[0058] On the other hand, in the case of a conventional power transmission device in which, for example, the first clutch member 4a and the pressure member 5 do not come into contact and there is no first torque region α1 (only a torque region β exists), as shown in Figure 27, when the weight member 10 of the centrifugal clutch means 9 moves from the inner diameter side position to the outer diameter side position, a torque is generated from the input gear 1 (input member) to the output shaft 3 (output member), and at the same time the pressure contact assist cam is activated, power transmission occurs suddenly and unintentionally when the vehicle starts, making smooth driving difficult.

[0059] According to this embodiment, in the process in which the weight member 10 of the centrifugal clutch means 9 moves from the inner diameter side position to the outer diameter side position and the transmission torque from the input gear 1 (input member) to the output shaft 3 (output member) increases, there is a first torque region α1 that restricts the operation of the pressure-contact assist cam and a second torque region α2 that allows the operation of the pressure-contact assist cam. Therefore, in a vehicle equipped with the centrifugal clutch means 9, it is possible to prevent the pressure-contact assist cam from operating unintentionally when the vehicle starts up, which could cause power transmission to occur suddenly at an unintended timing.

[0060] Furthermore, the clutch member according to this embodiment includes a first clutch member 4a connected to the output shaft 3 (output member) and a second clutch member 4b to which the driven clutch plate 7 is attached. The pressure assist cam is configured such that a gradient surface 4aa formed on the first clutch member 4a and a gradient surface 5a formed on the pressure member 5 face each other, so that the pressure assist cam can be operated by the first clutch member 4a and the pressure member 5.

[0061] Furthermore, in the first torque region α1, the first clutch member 4a and the pressure member 5 come into contact, restricting the operation of the pressure assist cam, while in the second torque region α2, the first clutch member 4a and the pressure member 5 separate, allowing the operation of the pressure assist cam to be permitted. This allows for accurate and smooth restriction of the operation of the pressure assist cam in the first torque region α1 and permission for its operation in the second torque region α2.

[0062] Furthermore, in the first torque region α1, the centrifugal clutch means 9 moves the second clutch member 4b without moving the first clutch member 4a, thereby maintaining the contact state between the first clutch member 4a and the pressure member 5. In the second torque region α2, the centrifugal clutch means 9 moves both the second clutch member 4a and the pressure member 5, separating the first clutch member 4a and the pressure member 5. Thus, the operation of the pressure-assist cam in the first torque region α1 and the operation of the pressure-assist cam in the second torque region α2 can be controlled by the operation of the centrifugal clutch means 9.

[0063] In particular, in this embodiment, the centrifugal clutch means 9 transitions from the first torque region α1 to the second torque region α2 during the operation process (the process of moving the weight member 10 from the inner diameter side position to the outer diameter side position). Therefore, the operation of the pressure-assist cam in the first torque region α1 and the operation of the pressure-assist cam in the second torque region α2 can be controlled continuously and smoothly.

[0064] Although this embodiment has been described above, the present invention is not limited to these embodiments. For example, the invention may also have a back torque limiter cam (gradient surface 4ab and gradient surface 5b), an auxiliary clutch plate 17, or a centrifugal clutch means 9 of a different form (such as one having a weight member made of steel balls). The power transmission device of the present invention can be applied to various multi-plate clutch type power transmission devices such as motorcycles, automobiles, three-wheeled or four-wheeled buggies, or general-purpose machines. [Industrial applicability]

[0065] A power transmission device having a first torque region that restricts the operation of a pressure-assist cam and a second torque region that allows the operation of a pressure-assist cam during the process in which the weight member of the centrifugal clutch means moves from the inner diameter side position to the outer diameter side position, thereby increasing the transmission torque from the input member to the output member, can be applied to devices with different external shapes or those with added functions. [Explanation of symbols]

[0066] 1. Input gear (input component) 2 Clutch Housing 2a notch 3. Output shaft (output component) 4a First clutch member 4aa Gradient surface (cam for pressure assist) 4ab Gradient surface (cam for back torque limiter) 4ac Boss Section 4ad Contact surface 4b Second clutch member 4ba spline mating section 4bb flange section 5. Pressure Member 5a Gradient surface (cam for pressure contact assist) 5b Gradient surface (cam for back torque limiter) 5c flange section 5d inset hole 5e Contact surface 6. Drive-side clutch plate 7. Passed clutch plate 8 Fixing member 9. Centrifugal clutch mechanism 10 Weight Member 10a through hole 10aa One opening 10ab Other opening 10b Insertion section 10ba end wall 10c groove 11 Retaining member 11a Storage area 11aa Inner circumferential wall surface 11b Groove shape 11c Pressing surface 12. Pressure-welded 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. Biasing 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 with the driving force of the vehicle's engine and is housed in a clutch housing to which a plurality of drive-side clutch plates are attached, wherein a plurality of driven-side clutch plates are attached alternately with the drive-side clutch plates, and the clutch member is connected to an output member capable of rotating the vehicle's wheels, A pressure member is movable between an operating position in which the drive-side clutch plate and the driven-side clutch plate are pressed together to enable the transmission of the engine's driving force to the wheels, and a non-operating position in which the pressing force between the drive-side clutch plate and the driven-side clutch plate is released, thereby blocking the transmission of the engine's driving force to the wheels. A centrifugal clutch means comprising a weight member that is movable from an inner diameter side position to an outer diameter side position by centrifugal force accompanying the rotation of the clutch housing, wherein when the weight member is in the outer diameter side position, the drive side clutch plate and the driven side clutch plate are pressed together to enable the transmission of the engine's driving force to the wheel, and when the weight member is in the inner diameter side position, the pressing force between the drive side clutch plate and the driven side clutch plate is released to block the transmission of the engine's driving force to the wheel, A power transmission device equipped with, The centrifugal clutch means is A holding member that holds the weight member so as to be movable between the inner diameter side position and the outer diameter side position, The weight member moves from the inner diameter side position to the outer diameter side position, thereby moving in the stacking direction of the drive-side clutch plate and the driven-side clutch plate, causing the drive-side clutch plate and the driven-side clutch plate to press against each other. The weight member comprises a biasing member that biases the weight member from the outer diameter side position toward the inner diameter side position, The aforementioned weight member is The weight itself, The weight body has a spherical member that protrudes from the output member in the axial direction and contacts the pressure contact member, The aforementioned weight body is One side facing the first direction, which is one side in the axial direction, It has another side facing a second direction, which is the other side in the axial direction, A recess opening in the axial direction is formed on one of the aforementioned sides. The biasing member extends radially within the recess, When viewed from the radial direction, the axis of the biasing member is located on the first direction side of the axial midpoint between the outermost surface on the second direction side of the other side and the outermost surface on the first direction side of the one side, A power transmission device wherein the radial outer edge of the other side is located on the first direction side of the radial inner edge of the other side.

2. The power transmission device according to claim 1, wherein the radially outer portion of the other side is inclined so as it moves radially outward, it moves toward the first direction.

3. A clutch member that rotates together with an input member that rotates with the driving force of the vehicle's engine and is housed in a clutch housing to which a plurality of drive-side clutch plates are attached, wherein a plurality of driven-side clutch plates are attached alternately with the drive-side clutch plates, and the clutch member is connected to an output member capable of rotating the vehicle's wheels, A pressure member is movable between an operating position in which the drive-side clutch plate and the driven-side clutch plate are pressed together to enable the transmission of the engine's driving force to the wheels, and a non-operating position in which the pressing force between the drive-side clutch plate and the driven-side clutch plate is released, thereby blocking the transmission of the engine's driving force to the wheels. A centrifugal clutch means comprising a weight member that is movable from an inner diameter side position to an outer diameter side position by centrifugal force accompanying the rotation of the clutch housing, wherein when the weight member is in the outer diameter side position, the drive side clutch plate and the driven side clutch plate are pressed together to enable the transmission of the engine's driving force to the wheel, and when the weight member is in the inner diameter side position, the pressing force between the drive side clutch plate and the driven side clutch plate is released to block the transmission of the engine's driving force to the wheel, A power transmission device equipped with, The centrifugal clutch means is A holding member that holds the weight member so as to be movable between the inner diameter side position and the outer diameter side position, The weight member moves from the inner diameter side position to the outer diameter side position, thereby moving in the stacking direction of the drive-side clutch plate and the driven-side clutch plate, causing the drive-side clutch plate and the driven-side clutch plate to press against each other. The weight member comprises a biasing member that biases the weight member from the outer diameter side position toward the inner diameter side position, The aforementioned weight member is The weight itself, The weight body has a spherical member that protrudes from the output member in the axial direction and contacts the pressure contact member, The aforementioned weight body is One side facing the first direction, which is one side in the axial direction, It has another side facing a second direction, which is the other side in the axial direction, A recess opening in the axial direction is formed on one of the aforementioned sides. The biasing member extends radially within the recess, When viewed from the radial direction, the axis of the biasing member is located on the first direction side of the axial midpoint between the outermost surface on the second direction side of the other side and the outermost surface on the first direction side of the one side, The weight body has a through hole that penetrates in the axial direction. The aforementioned spherical member is A first spherical member is placed in the through hole, with a portion of it protruding from the opening on the second side of the through hole, The through-hole is disposed of and a portion of which protrudes from the opening on the first side of the through-hole, A power transmission device in which the diameter of the first spherical member is smaller than the diameter of the second spherical member.

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