JP4656509B2 - Transmission clutch structure - Google Patents

Description

  The present invention relates to a clutch structure of a transmission.

  2. Description of the Related Art Conventionally, in a transmission of a vehicle such as an automobile, an input includes a multi-plate clutch in which a plurality of clutch plates and a plurality of clutch disks are alternately arranged, and a peripheral wall portion in which the plurality of clutch plates are spline-engaged in an inner fit. Side clutch drum, an output side clutch hub having a peripheral wall portion in which a plurality of clutch disks are spline-engaged in an external fitting manner, and a clutch piston capable of pressing a multi-plate clutch in the fastening direction, and actuates the clutch piston A clutch structure of a transmission that controls the fastening force of a multi-plate clutch by adjusting the hydraulic pressure is practically used.

  In the hydraulic clutch for automatic transmission of Patent Document 1, a plurality of clutch plates are spline-engaged with the outer peripheral wall portion of the clutch drum so as to fit inside, and the clutch piston is interposed between the outer peripheral wall portion and the inner peripheral wall portion of the clutch drum. The clutch piston is slidably fitted in the axial direction, and a hydraulic working chamber is provided on the side opposite to the multi-plate clutch of the clutch piston. A cancel piston is fitted on the multi-plate clutch side of the clutch piston between the outer peripheral wall portion and the inner peripheral wall portion of the clutch drum, and a cancel chamber is provided between the cancel piston and the clutch piston. By supplying lubricating oil to the cancel chamber, the hydraulic pressure generated by the centrifugal force and acting on the clutch piston is balanced.

  The clutch piston is configured to move between an operating position that presses the multi-plate clutch and a non-operating position that does not press the multi-plate clutch, and the cancel chamber is equipped with a return spring that biases the clutch piston to the non-operating position. Has been. When the clutch piston is located at the non-actuated position, the multi-plate clutch is opened, and when a predetermined low pressure is supplied to the hydraulic working chamber, the clutch piston moves to the actuated position and lightly presses the multi-plate clutch. When the multi-plate clutch is finely engaged, and when a predetermined high pressure is supplied to the hydraulic operation chamber, the clutch piston strongly presses the multi-plate clutch, and the multi-plate clutch is completely engaged. .

By the way, the clutch piston is provided in a state of being slidably fitted in the axial direction between the outer peripheral wall portion and the inner peripheral wall portion of the clutch drum, and its axial center is concentric with the main shaft of the engine. As usual, when the transmission is mounted on the vehicle, the clutch piston receives gravity in a direction perpendicular to the shaft center, so that the clutch piston as a whole may tilt at least slightly from a normal posture capable of pressing the multi-plate clutch. .
JP-A-11-182579

  As described above, there is a possibility that the clutch piston may tilt from the normal posture, and if the clutch piston is tilted, there is a possibility that the pressing force cannot be uniformly applied from the clutch piston to the multi-plate clutch. It is difficult to achieve When the clutch piston is tilted, if a pressing force is applied from the clutch piston to the multi-plate clutch, the reaction force causes the clutch piston to return to the normal posture, but at least until the return, the multi-plate clutch is pressed. Pressure cannot be applied uniformly.

  Here, for example, in order to realize improvement in fuel consumption during idling, reduction of engine load when the vehicle is idling in the driving range, and prevention of shock at start-up, the multi-plate clutch is not completely released in the forward clutch, for example. So-called neutral idle control, in which a fine engagement state is made to slide, is widely applied. However, when the multi-plate clutch is in the finely engaged state, if the clutch piston is tilted, the pressing force is small, and the clutch piston is also difficult to return to the normal posture. It is difficult to achieve

  An object of the present invention is to provide a clutch structure for a transmission that can stabilize the engagement control of a multi-plate clutch, and in particular, can stabilize the fine engagement control.

The clutch structure of the transmission according to claim 1 includes a multi-plate clutch in which a plurality of clutch plates and a plurality of clutch disks are alternately arranged, a clutch drum having an outer peripheral wall portion in which the plurality of clutch plates are spline-engaged, A clutch piston that is slidably fitted in the axial direction between the outer peripheral wall portion and the inner peripheral wall portion of the clutch drum and that can press the multi-plate clutch in the fastening direction, and adjusts the hydraulic pressure for operating the clutch piston. In the clutch structure of the transmission that controls the fastening force of the multi-plate clutch, a plurality of small-diameter piston members that can be pressed by the hydraulic pressure that operates the clutch piston to press the multi-plate clutch are included in the multi-plate clutch of the clutch piston. the portion facing provided circumferentially equal intervals and, the axis of the plurality of small-diameter piston member, Kura the closer to the multi-plate clutch And it is inclined so as to approach the axis of Chipisuton.

  In this transmission clutch structure, a plurality of small-diameter piston members are provided at equal intervals in the circumferential direction in a portion of the clutch piston facing the multi-plate clutch, and the plurality of small-diameter piston members are operated by hydraulic pressure that operates the clutch piston. Thus, the multi-plate clutch can be pressed. Since the plurality of small diameter piston members can be moved back and forth in the operating state, and the same pressing force can be generated at any forward and backward positions, all of the plurality of small diameter piston members are The multi-plate clutch is pressed with the same pressing force in contact with the plate clutch, so that the pressing force is uniformly applied to the multi-plate clutch.

Here, the following configuration can be appropriately adopted in the invention of claim 1.
The clutch piston has a pressing portion that presses the multi-plate clutch, and the plurality of small-diameter piston members are at the same position as the protruding portion that protrudes toward the multi-plate clutch with respect to the pressing portion, at least in the axial direction. It is configured to be movable over the retreat position where the user has retreated. The clutch piston is configured to be movable between an operating position in which the pressing portion presses the multi-plate clutch and a non-operating position in which the multi-plate clutch is not pressed, and in an operating region where the fastening force of the multi-plate clutch is small. When the hydraulic pressure is a predetermined low pressure, the clutch piston is positioned at the non-operating position, and the plurality of small-diameter piston members are positioned at the protruding position to press the multi-plate clutch (Claim 3). When the hydraulic pressure is a predetermined high pressure in an operating region where the engagement force of the multi-plate clutch is large, the clutch piston is positioned at the operating position to press the multi-plate clutch (Claim 4) .

  According to the clutch structure of the transmission according to claim 1, the clutch structure of the transmission includes a multi-plate clutch, a clutch drum, and a clutch piston, and controls the fastening force of the multi-plate clutch by adjusting the hydraulic pressure that operates the clutch piston. In the present invention, a plurality of small-diameter piston members that can be pressed by the hydraulic pressure that operates the clutch piston to press the multi-plate clutch are provided at equal intervals in the circumferential direction in the portion of the clutch piston that faces the multi-plate clutch. When the small-diameter piston member is in an operating state, it can be moved back and forth, and the same pressing force can be generated at any forward / backward position, so even if the clutch piston is tilted, all of the multiple small-diameter piston members are multi-plate clutches. The multi-plate clutch can be pressed with the same pressing force.

That is, since the pressing force can be uniformly applied to the multi-plate clutch from the plurality of small-diameter piston members, the fastening control of the multi-plate clutch can be stabilized. In particular, when the multi-plate clutch is in a slightly engaged state such as a neutral idle state, the pressing force is small, but even when the clutch piston is tilted and even when it is difficult to return to a normal posture, a plurality of small diameter piston members are used. Since a pressing force can be uniformly applied to the multi-plate clutch, it is possible to stabilize the fine engagement control of the multi-plate clutch. Also, by providing a plurality of small-diameter piston members at equal intervals in the circumferential direction of the clutch piston, the rotation balance of the clutch piston is maintained, and the hydraulic pressure for operating the clutch piston is used as the hydraulic pressure for operating the small-diameter piston member. The structure for supplying hydraulic pressure to the small diameter piston member can be simplified. Moreover, since the shaft centers of a plurality of small-diameter piston members are inclined so as to approach the shaft center of the clutch piston as they approach the multi-plate clutch, the clutch piston rotates at a relatively high speed when the multi-plate clutch is in an open state. In this case, the plurality of non-actuated small-diameter piston members are moved to the retracted position by centrifugal force. That is, even when a plurality of small-diameter piston members are facing the portion that supplies the lubricating oil, the drag resistance (viscosity resistance) caused by the lubricating oil received by the plurality of small-diameter piston members when the multi-plate clutch is released during high-speed rotation is reduced. Thus, it becomes possible to improve the fuel consumption by reducing the braking force.

  According to the clutch structure of the transmission according to claim 2, the clutch piston has a pressing portion that presses the multi-plate clutch, and the plurality of small-diameter piston members protrude from the pressing portion toward the multi-plate clutch. Since it is configured to be movable over at least the retracted position retracted at the same position as the pressing portion in the axial direction, a plurality of small diameter piston members are positioned at the projecting positions, and the plurality of small diameter piston members The clutch can be lightly pressed to be in a finely engaged state, a plurality of small diameter piston members can be positioned in the retracted position, and the multi-plate clutch can be strongly pressed by at least the pressing portion of the clutch piston to be in a fully engaged state it can.

  According to the clutch structure of the transmission according to claim 3, the clutch piston is configured to be movable between an operation position where the pressing portion presses the multi-plate clutch and a non-operation position where the multi-plate clutch is not pressed, When the hydraulic pressure is a predetermined low pressure in an operating region where the engaging force of the multi-plate clutch is small, the clutch piston is positioned at the non-operating position, and the plurality of small-diameter piston members are positioned at the protruding position to press the multi-plate clutch. Since the hydraulic pressure is set to a predetermined low pressure, the multi-plate clutch is reliably pressed by a plurality of small-diameter piston members, and the fastening force of the multi-plate clutch is reduced to achieve a stable fine engagement state. be able to.

  According to the clutch structure of the transmission of claim 4, when the hydraulic pressure is a predetermined high pressure in an operation region where the fastening force of the multi-plate clutch is large, the clutch piston is positioned at the operating position so as to press the multi-plate clutch. Therefore, by setting the hydraulic pressure to a predetermined high pressure, the multi-plate clutch can be surely pressed at least by the pressing portion of the clutch piston, and the fastening force of the multi-plate clutch can be increased to ensure a fully engaged state. it can.

  The clutch structure of the transmission according to the present embodiment includes a multi-plate clutch in which a plurality of clutch plates and a plurality of clutch disks are alternately arranged, a clutch drum having an outer peripheral wall portion in which a plurality of clutch plates are spline-engaged, A clutch piston that is slidably fitted in the axial direction between the outer peripheral wall portion and the inner peripheral wall portion of the clutch drum and that can press the multi-plate clutch in the fastening direction, and adjusts the hydraulic pressure for operating the clutch piston. In particular, the engagement force of the multi-plate clutch is controlled, and in particular, a plurality of small-diameter piston members that can be pressed by the hydraulic pressure that operates the clutch piston to press the multi-plate clutch, They are provided at opposite intervals at equal intervals in the circumferential direction.

  As shown in FIGS. 1 to 3, a clutch structure 1 (clutch device 1) of a transmission includes a casing 2, an input shaft 3, a clutch drum 4, a clutch hub 5, a multi-plate clutch 7, a clutch housing chamber 8, a clutch piston. 9, a return spring unit 10, a hydraulic working chamber 11, a partition plate member 12 (also referred to as a seal plate 12 or a centrifugal balance piston 12), and a centrifugal balance chamber 13, and driving force is input to the input shaft 3, and this input shaft 3 is transmitted to the clutch hub 5 through the engaged multi-plate clutch 7 from the clutch drum 4 that is rotationally driven integrally with the clutch drum 5, and the clutch hub 5 is rotationally driven and output. In the following description, the front indicated by the arrow in FIG.

  A thick-walled cylindrical clutch support 20 is integrally formed in the casing 2. The input shaft 3 is fitted into the clutch support 20 and is rotatably supported via bearings 21 a to 21 c, and a clutch drum. 4 is externally fitted through two sets of annular seal members 22 and is rotatably supported. In the casing 2, hydraulic passages 23 a to 23 c are formed for supplying hydraulic pressure supplied from a hydraulic control unit (not shown) including an external hydraulic circuit to the hydraulic working chamber 11 for operating the clutch piston 9. ing.

  A flange portion 25 is formed integrally with the input shaft 3, and the flange portion 25 is located on the rear side of the clutch support 20. A rear end portion of the inner peripheral wall portion 31 of the clutch drum 4 is formed on the outer peripheral portion of the flange portion 25. The partition plate member 12 is externally fitted and fixed to the rear portion of the flange portion 25 of the input shaft 3. The input shaft 3 is formed with a lubricating oil passage 26 a at the shaft center portion, from the lubricating oil passage 26 a between the input shaft 3 and the clutch support 20, between the centrifugal balance chamber 13 and between the input shaft 3 and the clutch hub 5. Lubricating oil passages 26 b to 26 d for supplying lubricating oil are formed, and a lubricating oil passage 26 e for supplying lubricating oil from the centrifugal balance chamber 13 between the input shaft 3 and the clutch support 20 is formed in the flange portion 25.

  The clutch drum 4 has an outer peripheral wall portion 30, an inner peripheral wall portion 31, and a front end wall portion 32. Most of the outer peripheral wall portion 30 other than the front end portion is formed in the plate mounting portion, and a plurality of (for example, four) ring plate-like clutch plates 45 of the multi-plate clutch 7 are axially arranged on the plate mounting portion. A plurality of spline engaging teeth 30a and 45a are formed on the inner surface of the outer peripheral wall 30 and the outer peripheral portion of each clutch plate 45, respectively. The rear end portion of the inner peripheral wall portion 31 is located inside the central portion in the front-rear direction of the outer peripheral wall portion 30, and hydraulic pressure is supplied to the inner peripheral wall portion 31 from the hydraulic passages 23 b and 23 c of the clutch support 20. A hydraulic passage 33 is formed for this purpose.

  The clutch hub 5 includes a peripheral wall portion 40, a ring portion 41, and a tubular portion 42, and the tubular portion 42 is connected to an output side member (not shown). The peripheral wall portion 40 has a diameter of about 3/5 of the outer peripheral wall portion 30 of the clutch drum 4, and a plurality of (for example, four) ring plate-like clutch disks 46 of the multi-plate clutch 7 are formed on the peripheral wall portion 40. A plurality of spline engaging teeth 40a, 46a are formed on the outer surface of the peripheral wall 40 and the inner peripheral portion of each clutch disk 46, respectively, so that the spline is engaged in an axially movable manner. ing.

  The multi-plate clutch 7 includes a plurality of clutch plates 45, a plurality of clutch disks 46, and a retaining plate 47, and a space for housing the multi-plate clutch 7 is a clutch housing chamber 8. The plurality of clutch plates 45 and the plurality of clutch disks 46 are alternately arranged in the front-rear direction so that the clutch plates 45 are positioned at the front ends thereof, and as described above, the clutch plates 45 and the clutch disks 46 are arranged on the clutch drum 4. The outer peripheral wall 30 and the peripheral wall 40 of the clutch hub 5 are spline-engaged.

  The retaining plate 47 is formed in the shape of a thick ring plate in the front-rear direction, and is disposed in contact with the rear side of the clutch disk 46 at the rear end. The outer peripheral portion of the retaining plate 47 is spline-engaged with the outer peripheral wall portion 30 of the clutch drum 4, is fixed to the outer peripheral wall portion 30 so as not to move rearward, and is restricted by a restricting member 48.

  The clutch piston 9 is slidably fitted in the axial direction between the outer peripheral wall portion 30 and the inner peripheral wall portion 31 of the clutch drum 4, and between the clutch piston 9 and the outer peripheral wall portion 30 by the seal member 50, The space between the clutch piston 9 and the inner peripheral wall portion 31 is sealed. The clutch piston 9 is formed with an annular recess 9a that is recessed forward with respect to its inner and outer peripheral portions, and a thick-walled cylindrical projecting portion 9b that protrudes rearward with respect to the front wall of the annular recess 9b at the outer peripheral portion. An annular pressing portion 49 that can contact the clutch plate 45 and press the multi-plate clutch 7 is fixed to the rear end portion of the protruding portion 9b, and a ring-shaped member that is separate from the protruding portion 9b is fixed to the rear end portion of the protruding portion 9b. Is provided.

  The clutch piston 9 can move between an operating position where the pressing portion 49 presses the multi-plate clutch 7 (see FIG. 3) and a non-operating position where the multi-plate clutch 7 is not pressed (see FIGS. 1 and 2). It is configured. The seal member 50 includes an annular first seal portion 50a that seals between the clutch piston 9 and the outer peripheral wall portion 30, an annular second seal portion 50b that seals between the clutch piston 9 and the inner peripheral wall portion 31, and a clutch. And a portion surrounded by the seal member 50 and the clutch drum 4 on the front side of the clutch piston 9 is formed in the hydraulic working chamber 11. Yes.

  The partition plate member 12 is formed by integrally forming a rear end wall portion 55, a cylindrical portion 56, and a front end wall portion 57, and the outer peripheral portion of the rear end wall portion 55 is connected to the rear end portion of the cylindrical portion 56. The front end portion of the portion 56 is connected to the inner peripheral portion of the front end wall portion 57. The rear end wall portion 55 is fixed to the input shaft 3 so as to be fitted onto the input shaft 3, and the partition plate member 12 is disposed with a predetermined gap with respect to the clutch drum 4, the clutch hub 5, and the multi-plate clutch 7. The front end wall portion 57 is positioned on the front side of the multi-plate clutch 7 and is inserted into the annular recess 9a of the clutch piston 9. The pressing portion 9b of the clutch piston 9 is inserted into the outer peripheral portion of the front end wall portion 57 via the annular seal member 58. Is externally fitted so as to be movable in the axial direction.

  A portion surrounded by the partition plate member 12, the clutch piston 9 and the input shaft 3 is formed in the centrifugal balance chamber 13. The centrifugal balance chamber 13 is provided on the side of the multi-plate clutch 7 of the clutch piston 9 for balancing the hydraulic pressure generated by the centrifugal force. The centrifugal balance chamber 13 and the clutch housing chamber 8 are separated by the partition plate member 12. It is partitioned by. In the centrifugal balance chamber 13, the return spring unit 10 is mounted between the vicinity of the outer periphery of the rear end wall portion 55 of the partition plate member 12 and the vicinity of the inner periphery of the clutch piston 9.

  The return spring unit 10 includes a front spring receiving member 10a that contacts the clutch piston 9, a rear spring receiving member 10b that contacts the partition plate member 12, and a coil spring 10c mounted between the spring receiving members 10a and 10b. The return spring unit 10 urges the clutch piston 9 forward, that is, in a direction to release the engagement of the multi-plate clutch 7. One return spring unit 10 may be provided in an annular shape. In this case, a plurality of coil springs 10c may be mounted on a common annular spring receiving member 10a, 10b, or a plurality of non-annular return springs may be provided. A unit 10 may be provided. Further, as the return spring unit 10, various spring means such as a simple spring member can be applied.

  The clutch structure 1 of the transmission includes a plurality of (for example, three or four) small-diameter piston members 60 that can be pressed by the hydraulic pressure that operates the clutch piston 9 to press the multi-plate clutch 7. 9 at equal intervals in the circumferential direction at positions facing the multi-plate clutch 7 (every 120 degrees when there are three small-diameter piston members 60, and every 90 degrees when there are four small-diameter piston members 60). ) Is provided. Next, the small-diameter piston member 60 and the surrounding structure will be described in detail.

  As shown in FIGS. 4 to 6, each small-diameter piston member 60 includes a piston portion 60a and an output rod portion 60b having a smaller diameter than the piston portion 60a. A plurality of piston holes 61 of the same number as the small-diameter piston member 60 are formed in the protruding portion 9b of the clutch piston 9 at equal intervals in the circumferential direction, and the piston portions 60a of the small-diameter piston members 60 are slidable in the piston holes 61. The front end portion of the output rod portion 60b faces the multi-plate clutch 7 by being internally fitted, and the plurality of small-diameter piston members 60 (output rod portions 60b) protrude toward the multi-plate clutch 7 side (rear side) from the pressing portion 49. It is configured to be movable between the protruding position (see FIG. 5) and the retracted position (see FIGS. 4 and 6) retracted to the same position as the pressing portion 49 in the axial direction (front-rear direction). ing.

  More specifically, the rear end portion of the projecting portion 9b of the clutch piston 9 includes an annular rear end vertical surface 9c including the outer peripheral end, and the clutch from the inner peripheral end of the rear end vertical surface 9c toward the front side. An annular tapered surface 9d that is inclined toward the axial center of the drum 4 is formed, and a pressing portion 49 is fixed to the rear end vertical surface 9c. The piston hole 61 is formed such that its center line is substantially orthogonal to the tapered surface 9d and opens toward the tapered surface 9d. The pressing portion 49 is integrally formed with a tapered portion 49a that is inclined toward the axial center side of the clutch drum 4 from the inner peripheral end portion toward the front side.

  The tapered portion 49a is provided in an annular shape or at least partially at the front side portion of the piston hole 61, and is held in contact with the tapered surface 9d. The taper portion 49 a has a plurality of projecting holes 49 b that are the same in number as the plurality of piston holes 61 and coincide with the piston holes 61. Each protruding hole 49b is formed to have substantially the same diameter as the output rod portion 60b, and the output rod portion 60b of each small-diameter piston member 60 is inserted into each protruding hole 49b so as to be able to advance and retract. The piston portion 60b (small-diameter piston member 60) is prevented from coming off by the taper portion 49a. The shaft centers of the plurality of small-diameter piston members 60 thus mounted are inclined so as to approach the shaft center of the clutch piston 9 as they approach the multi-plate clutch 7 (rear side).

  With respect to the structure for operating the plurality of small diameter piston members 60 with the hydraulic pressure for operating the clutch piston 9, a small diameter piston oil chamber 62 is formed in front of the piston portion 60a of the small diameter piston member 60 in each piston hole 61. An oil passage 63 that connects the small-diameter piston oil chamber 62 and the hydraulic working chamber 11 is formed in parallel with the axial direction of the clutch piston 9. When the hydraulic pressure is supplied to the hydraulic working chamber 11, the hydraulic pressure is also supplied to the plurality of small diameter piston oil chambers 62 via the plurality of oil passages 63, and the plurality of small diameter piston members 60 receive the hydraulic pressure received by the piston portion 60a. Is driven to the protruding side.

  When the hydraulic pressure supplied to the hydraulic operating chamber 11 is a predetermined low pressure in an operating region where the engagement force of the multi-plate clutch 7 is small, as shown in FIG. FIG. 6 shows a case where the small-diameter piston member 60 is positioned at the protruding position to press the multi-plate clutch 7 and the hydraulic pressure supplied to the hydraulic working chamber 11 is a predetermined high pressure in the operating region where the multi-plate clutch 7 is fastened. As shown, the clutch piston 9 is positioned at the operating position so as to press the multi-plate clutch 7.

The operation and effect of the clutch structure 1 of the transmission will be described.
As shown in FIGS. 1 and 4, the clutch piston 9 is held in the non-operating position by the biasing force of the return spring unit 10 in a state where the hydraulic pressure in the hydraulic working chamber 11 is released, and the plurality of small-diameter piston members 60 are It rotates with the clutch piston 9 (clutch drum 4) to generate centrifugal force, and is held in the retracted position by the centrifugal force, so that the multi-plate clutch 7 is in a non-engaged state.

  As shown in FIGS. 2 and 5, when a predetermined low pressure hydraulic pressure is supplied to the hydraulic working chamber 11, the clutch piston 9 is still held at the non-operating position by the biasing force of the return spring unit 10, and the predetermined low pressure hydraulic pressure is maintained. Is supplied to the plurality of small-diameter piston oil chambers 62 via the passages 63 from the hydraulic operation chamber 11, and the plurality of small-diameter piston members 60 are moved from the retracted position to the protruding position against the centrifugal force by the hydraulic pressure. Then, the multi-plate clutch 7 is lightly pressed, and the operation region where the fastening force of the multi-plate clutch 7 is small, that is, the multi-plate clutch 7 is in a slightly engaged state.

  As shown in FIGS. 3 and 6, when a predetermined high pressure is supplied to the hydraulic operating chamber 11, the clutch piston 9 moves from the non-operating position to the operating position against the urging force of the return spring unit 10. The multi-plate clutch 7 is pressed strongly. Here, the predetermined high pressure oil pressure is supplied from the hydraulic working chamber 11 to the plurality of small diameter piston oil chambers 62 via the passages 63, and the plurality of small diameter piston members 60 are driven to the protruding side by the oil pressure. As the clutch piston 9 moves to the operating position, it moves from the projecting position to the retracted position and presses the multi-plate clutch 7. Thus, the operating region where the engagement force of the multi-plate clutch 7 is large, that is, the multi-plate clutch 7 is in a completely engaged state.

  When the multi-plate clutch 7 is switched from the finely engaged state or the completely engaged state to the released state, when the hydraulic pressure in the hydraulic operating chamber 11 is released, the clutch piston 9 is moved from the operating position to the non-operating position by the urging force of the return spring unit 10. The plurality of small-diameter piston members 60 are moved to the retracted position by the centrifugal force generated by rotating together with the clutch piston 9 (clutch drum 4), and the multi-plate clutch 7 is brought into a non-engaged state.

  In this way, a plurality of small-diameter piston members 60 that can be actuated by hydraulic pressure to actuate the clutch piston 9 to press the multi-plate clutch 7 are arranged at equal intervals in the circumferential direction at portions of the clutch piston 9 that face the multi-plate clutch 7. Therefore, even when the clutch piston 9 is tilted, a plurality of small-diameter piston members 60 can be advanced and retracted when the small-diameter piston members 60 are in an operating state. All of the small-diameter piston members 60 abut against the multi-plate clutch 7 so that the multi-plate clutch 7 can be pressed with the same pressing force.

  That is, since the pressing force can be uniformly applied to the multi-plate clutch 7 from the plurality of small-diameter piston members 60, the fastening control of the multi-plate clutch 7 can be stabilized. In particular, when the multi-plate clutch 7 is in a slightly engaged state, such as in a neutral idle state, the pressing force is small, but even when the clutch piston 9 is tilted and even when it is difficult to return to a normal posture, a plurality of small diameter pistons Since the pressing force can be uniformly applied from the member 60 to the multi-plate clutch 9, the fine engagement control of the multi-plate clutch 7 can be stabilized.

  Further, by providing a plurality of small-diameter piston members 60 at equal intervals in the circumferential direction of the clutch piston 9, the rotation balance of the clutch piston 9 is maintained, and the clutch piston 9 is operated to a hydraulic pressure that operates the small-diameter piston member 60. Since the hydraulic pressure is used, the structure for supplying the hydraulic pressure to the small diameter piston member 60 can be simplified.

  The clutch piston 9 has a pressing portion 49 that presses the multi-plate clutch 7, and the plurality of small-diameter piston members 60 have a protruding position that protrudes toward the multi-plate clutch 7 from the pressing portion 49, and a pressing portion at least in the axial direction. 49, the plurality of small-diameter piston members 60 are positioned at the projecting positions, and the multi-plate clutch 7 is lightened by the plurality of small-diameter piston members 60. The plurality of small-diameter piston members 60 can be positioned in the retracted position by pressing, and the multi-plate clutch 7 is strongly pressed by at least the pressing portion 49 of the clutch piston 9 to be in the completely engaged state. Can do.

  When the hydraulic pressure for operating the clutch piston 9 is a predetermined low pressure in the operating region where the engagement force of the multi-plate clutch 7 is small, the clutch piston 9 is located at the non-actuated position and the plurality of small-diameter piston members 60 are located at the protruding positions. Since the multi-plate clutch 7 is configured to be pressed, the multi-plate clutch 7 is reliably pressed by the plurality of small-diameter piston members 60 by reducing the hydraulic pressure to a predetermined low pressure, and the fastening force of the multi-plate clutch 7 is reduced. Thus, a stable fine fastening state can be obtained.

  Since the clutch piston 9 is positioned at the operating position and presses the multi-plate clutch 7 when the hydraulic pressure for operating the clutch piston 9 in a working region where the fastening force of the multi-plate clutch 7 is large is a predetermined high pressure, By setting the hydraulic pressure to a predetermined high pressure, the multi-plate clutch 7 can be reliably pressed by the pressing portion 49 of the clutch piston 9, and the engagement force of the multi-plate clutch 7 can be increased to ensure a complete engagement state.

  Since the shaft centers of the plurality of small-diameter piston members 60 are inclined so as to approach the shaft center of the clutch piston 9 as they approach the multi-plate clutch 7, when the multi-plate clutch 7 is in the open state, the clutch piston 9 is relatively When rotating at a high speed, the plurality of non-actuated small-diameter piston members 60 move to the retracted position by centrifugal force. That is, the plurality of small-diameter piston members 60 face the portion where the lubricating oil is supplied, but the drag resistance (viscosity resistance) due to the lubricating oil received by the plurality of small-diameter piston members 60 when the multi-plate clutch 7 is released during high-speed rotation. It is possible to reduce the braking force and improve fuel efficiency.

  The number of small-diameter piston members 60 is not limited to three or four, and may be five or more. The plurality of small-diameter piston members 60 are opposed to the multi-plate clutch 7 of the clutch piston 9. It may be provided at equal intervals in the circumferential direction. Moreover, you may provide return means, such as a spring member, which returns each small diameter piston member 60 to a retracted position.

In the clutch structure 1A of the second embodiment, the clutch piston 9 of the clutch structure 1 of the first embodiment is partially changed, and the small-diameter piston member 60 and its surrounding structure are changed. Since other structures are the same as those of the clutch structure 1 of the first embodiment, the same reference numerals are given and description thereof is omitted.
As shown in FIGS. 7 to 9, in this clutch structure 1 </ b> A, a plurality of (for example, three or four) small-diameter piston members that can press the multi-plate clutch 7 by hydraulic pressure that operates the clutch piston 9 </ b> A. 70 are provided at equal intervals in the circumferential direction at portions facing the multi-plate clutch 7 in the clutch piston 9A.

  Each small-diameter piston member 70 includes a piston portion 70a and an output rod portion 70b having a smaller diameter than the piston portion 70a. A plurality of piston holes 71 of the same number as the small-diameter piston member 70 are formed in the protrusion 9e of the clutch piston 9A at equal intervals in the circumferential direction, and the piston portions 70a of the small-diameter piston members 70 are slidable in the piston holes 71. The inner end of the output rod portion 70b faces the multi-plate clutch 7, and the plurality of small-diameter piston members 70 (output rod portions 70b) protrude toward the multi-plate clutch 7 (rear side) from the pressing portion 49A. The projection position (see FIGS. 7 and 8) and the retracted position (see FIG. 9) retracted to the same position as the pressing portion 49A in at least the axial direction (front-rear direction) are configured to be movable. ing.

  Specifically, the pressing portion 49A is fixed to the rear end vertical surface 9f of the protrusion 9e of the clutch piston 9A, and the piston hole 71 has a center line parallel to the axis of the clutch piston 9A and the rear end vertical surface 9f. It is formed so as to open to the side. The pressing portion 49 </ b> A has a plurality of projecting holes 49 c that are the same number as the plurality of piston holes 71 and coincide with the piston holes 71. Each protruding hole 49c is formed to have substantially the same diameter as the output rod portion 70b, and the output rod portion 70b of each small-diameter piston member 70 is inserted into each protruding hole 49c so as to be able to advance and retract. The piston portion 70b (small diameter piston member 70) is prevented from coming off by the pressing portion 49A.

  With respect to the structure for operating the plurality of small diameter piston members 70 with the hydraulic pressure for operating the clutch piston 9A, a small diameter piston oil chamber 72 is formed in front of the piston portion 70a of the small diameter piston member 70 in each piston hole 71. An oil passage 73 that connects the small-diameter piston oil chamber 72 and the hydraulic working chamber 11 is formed in parallel with the axial direction of the clutch piston 9A. When the hydraulic pressure is supplied to the hydraulic working chamber 11, the hydraulic pressure is also supplied to the plurality of small diameter piston oil chambers 72 via the plurality of oil passages 73, and the plurality of small diameter piston members 70 are driven by the hydraulic pressure received by the piston portion 70a. Driven to the protruding side.

  When the hydraulic pressure supplied to the hydraulic operating chamber 11 is a predetermined low pressure in the operating region where the engagement force of the multi-plate clutch 7 is small, as shown in FIG. 8, the clutch piston 9A is positioned at the non-operating position, When the small-diameter piston member 70 is positioned at the protruding position to press the multi-plate clutch 7 and the hydraulic pressure supplied to the hydraulic working chamber 11 in the operating region where the multi-plate clutch 7 has a large fastening force is a predetermined high pressure, FIG. As shown, the clutch piston 9A is positioned at the operating position to press the multi-plate clutch 7.

  According to this clutch structure 1A, there are basically the same operations and effects as the clutch structure 1 of the first embodiment. However, since the shaft center of the small-diameter piston member 70 is parallel to the shaft center of the clutch piston 9A, the small-diameter piston member 70 moves to the retracted position side by centrifugal force generated by rotating integrally with the clutch piston 9A. No moving force is generated. Therefore, return means such as a spring member for returning each small-diameter piston member 70 to the retracted position may be provided.

  The number of small-diameter piston members 70 is not limited to three or four, and may be five or more. The plurality of small-diameter piston members 70 are opposed to the multi-plate clutch 7 in the clutch piston 9A. It may be provided at equal intervals in the circumferential direction. Further, when the small-diameter piston member 70 is in the retracted position, the small-diameter piston member 70 is positioned closer to the multi-plate clutch 7 than the pressing portion 49A, and is supplied to the hydraulic working chamber 11 in an operating region where the fastening force of the multi-plate clutch 7 is large. The clutch piston 9A may be configured to press the multi-plate clutch 7 via a plurality of small diameter piston members 70 when the hydraulic pressure to be applied is a predetermined high pressure.

  In addition, various modifications other than the matters disclosed in the first and second embodiments can be added without departing from the present invention, and the transmission clutch structure of the present invention can be applied to various automobiles and The present invention can be applied to various vehicles other than automobiles and various prime movers.

It is a longitudinal cross-sectional view of the clutch structure (open state) of the transmission of Example 1. It is a longitudinal cross-sectional view of the clutch structure (finely engaged state) of the transmission. It is a longitudinal cross-sectional view of the clutch structure (completely connected state) of a transmission. It is a longitudinal cross-sectional view of the principal part of the clutch structure of FIG. It is a longitudinal cross-sectional view of the principal part of the clutch structure of FIG. It is a longitudinal cross-sectional view of the principal part of the clutch structure of FIG. It is a longitudinal cross-sectional view of the clutch structure (open state) of the transmission of Example 2. It is a longitudinal cross-sectional view of the principal part of a clutch structure (finely engaged state). It is a longitudinal cross-sectional view of the principal part of a clutch structure (completely engaged state).

1, 1A Clutch structure 4 Clutch drum 7 Multi-plate clutch 9, 9A Clutch piston 30 Outer peripheral wall portion 45 Clutch plate 46 Clutch disc 49, 49A Pressing portion 60, 70 Small diameter piston member

Claims (4)

A multi-plate clutch in which a plurality of clutch plates and a plurality of clutch disks are alternately arranged; a clutch drum having an outer peripheral wall portion in which a plurality of clutch plates are spline-engaged; and an outer peripheral wall portion and an inner peripheral wall portion of the clutch drum; And a clutch piston that is slidably fitted in the axial direction and can press the multi-plate clutch in the fastening direction, and controls the fastening force of the multi-plate clutch by adjusting the hydraulic pressure that operates the clutch piston. In the clutch structure of the transmission,
A plurality of small-diameter piston members that can be pressed by a hydraulic pressure that operates the clutch piston to press the multi-plate clutch are provided at equal intervals in the circumferential direction at portions of the clutch piston that face the multi-plate clutch ,
A clutch structure for a transmission, wherein the shaft centers of the plurality of small-diameter piston members are inclined so as to approach the shaft center of the clutch piston as they approach the multi-plate clutch . The clutch piston has a pressing portion that presses the multi-plate clutch,
The plurality of small-diameter piston members are configured to be movable over a protruding position that protrudes toward the multi-plate clutch from the pressing portion and a retracted position that retreats at least at the same position as the pressing portion in the axial direction. The transmission clutch structure according to claim 1, wherein the transmission clutch structure is provided. The clutch piston is configured to be movable over an operating position where the pressing portion presses the multi-plate clutch and a non-operating position where the multi-plate clutch is not pressed,
When the hydraulic pressure is a predetermined low pressure in an operating region where the engaging force of the multi-plate clutch is small, the clutch piston is positioned at the non-operating position, and the plurality of small-diameter piston members are positioned at the projecting position. The clutch structure for a transmission according to claim 2, wherein the clutch structure is configured to be pressed.   4. The structure according to claim 3, wherein when the hydraulic pressure is a predetermined high pressure in an operating region where the fastening force of the multi-plate clutch is large, the clutch piston is positioned at the operating position to press the multi-plate clutch. The clutch structure of the described transmission.

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