JP2017067146A - Friction clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction clutch that can be formed in a compact size in an axial direction.SOLUTION: The friction clutch 1 for breaking or connecting power transmission between a clutch input member 5 and a clutch output member 2 by extending or contracting an interval between a clutch center 8 and a pressure plate 9 includes: a clutch outer 4; a torque limiter mechanism TL; and a limiter cancel mechanism LC. The pressure plate 9 is stored inside the clutch outer 4 and a restriction member RM is disposed between the pressure plate 9 and the clutch outer 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a friction clutch, and more particularly to a friction clutch provided with a torque limiter mechanism for reverse torque from the clutch output member side.

  Conventionally, various examples have been proposed in which a clutch is provided with a torque limiter mechanism that prevents excessive reverse torque from the rear wheels from being transmitted to the engine during downshifting or the like. In these examples, the friction engagement of the clutch is weakened by moving the pressure plate of the friction clutch away from the clutch center when reverse torque is input.

  On the other hand, in a motorcycle equipped with a kick starter mechanism, there is an example in which the kick starting torque is transmitted to the crankshaft via a clutch and used for starting the engine, but when a torque limiter mechanism is provided in the same example Since the torque limiter mechanism is activated by the kick start torque and the torque transmission to the engine is weakened and the engine cannot be started smoothly, the torque limit value for the torque limiter mechanism must be set high, and the original torque limiter mechanism Will be limited.

  Therefore, in Patent Document 1, when the rotational speed of the clutch center is equal to or lower than the rotational speed at idling, the centrifugal weight provided in the clutch center is closed to engage with the ratchet plate connected to the clutch release, A friction clutch is disclosed that transmits the rotation of the clutch center to a pressure plate connected to the clutch release. According to the friction clutch described in Patent Document 1, the torque limiter mechanism does not work at any time of kick start or push start, and the engine can be started smoothly. On the other hand, when reverse torque is input during downshifting during driving, the rotational speed of the clutch center exceeds the rotational speed at idling, and the torque limiter mechanism works without impairing the original function and overspeeding the engine It is possible to prevent engine brakes from being excessively effective.

Japanese Patent No. 3378100

  However, the friction clutch disclosed in Patent Document 1 has a problem that the friction clutch becomes larger in the axial direction because the centrifugal weight is supported by the clutch center and located outside the outer clutch.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a friction clutch that can be compactly formed in the axial direction.

In order to achieve the above object, the invention according to claim 1
A friction clutch that connects and disconnects power transmission between the clutch input member and the clutch output member by expanding and contracting the distance between the clutch center and the pressure plate,
A clutch outer which is cylindrical with a bottom and is rotatably supported by the clutch output member;
A torque limiter mechanism that moves the pressure plate in a direction that enlarges the interval with respect to the clutch center by input of torque from the clutch output member side;
A limiter cancellation mechanism that restrains the relative displacement of the pressure plate relative to the clutch center in one direction when the rotational speed of the clutch center is equal to or lower than the rotational speed at idling,
The pressure plate is housed inside the clutch outer;
The restraining member is disposed between the pressure plate and the clutch outer.

In addition to the structure of Claim 1, the invention according to Claim 2
The restraint member is constituted by a centrifugal weight and an engagement member that engages with the centrifugal weight when the clutch output member is not more than a predetermined rotation,
The centrifugal weight is fastened together with the clutch lifter to the pressure plate.

In addition to the structure of Claim 2, the invention which concerns on Claim 3 is
Both the pressure plate and the clutch center are made of aluminum,
The torque limiter mechanism is directly formed on the pressure plate and the clutch center itself.

In addition to the structure of any one of Claims 1-3, the invention which concerns on Claim 4 WHEREIN:
The pressure plate has a concave portion in which a central portion is recessed from an outer edge portion on a side where the restraining member is disposed,
The restraining member is disposed in the recess.

  According to the first aspect of the present invention, since the restraining member is disposed between the pressure plate and the clutch outer, the friction clutch can be formed compact in the axial direction.

  According to the invention of claim 2, since the centrifugal weight is fastened together with the clutch lifter to the pressure plate, it is not necessary to provide a separate fastening member for fastening the centrifugal weight, the number of parts can be reduced, and the space of the torque limiter mechanism can be reduced. Can be secured.

  According to the third aspect of the present invention, since the space for the torque limiter mechanism is secured, the torque limiter mechanism can be made relatively large. Therefore, the torque limiter mechanism is made of an aluminum pressure plate and a clutch center. Can be formed. Thereby, a friction clutch can be reduced in weight, ensuring required rigidity.

  According to the fourth aspect of the present invention, the friction clutch can be made more compact in the axial direction by accommodating the restraining member in the recess formed in the pressure plate.

It is sectional drawing of the friction clutch of one Embodiment of this invention. It is a perspective view of the pressure plate shown in FIG. It is the front view which looked at the pressure plate shown in FIG. 1 from the clutch center side. It is the front view which looked at the clutch center shown in FIG. 1 from the pressure plate side. (A) is explanatory drawing which shows the relative position of a pressure plate and a clutch center at the time of non-operation of a torque limiter mechanism in which the forward direction torque is input, (b) is a circumferential direction sectional view of a cam part. (A) is explanatory drawing which shows the relative position of a pressure plate and a clutch center at the time of the operation | movement of a torque limiter mechanism in which the torque of a reverse direction is input, (b) is a circumferential sectional view of a cam part. It is explanatory drawing explaining a limiter cancellation mechanism.

  Hereinafter, an embodiment of a friction clutch for a vehicle according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a friction clutch according to an embodiment of the present invention.

  As shown in FIG. 1, a clutch input gear 5, which is a clutch input member, is rotatably supported by the friction clutch 1 via a bearing 3 on a clutch output shaft 2, which is a clutch output member. The bottomed cylindrical clutch outer 4 is rotatably supported on the clutch output shaft 2 so as to rotate integrally with the clutch input gear 5.

  The clutch output shaft 2 projecting into the cylinder of the clutch outer 4 is spline-fitted with the ratchet plate 6 and the clutch center 8, and the nut 7 prevents the ratchet plate 6 and the clutch center 8 from moving in the axial direction. 2 and rotate together. The ratchet plate 6 and the clutch center 8 are positioned with respect to each other by a knock pin 13. The clutch center 8 is formed such that an annular disk portion 8b extends radially outward from a central cylindrical portion 8a that is spline-fitted to the clutch output shaft 2, and an outer peripheral edge portion 8c projects outward. The clutch output shaft 2 is fixed so as to close the opening of the outer 4.

  Relative rotation of the pressure plate 9 on the outer periphery of the central cylindrical portion 8a of the clutch center 8 and the inner side of the annular disc portion 8b of the clutch center 8 in addition to the axial inner sliding. Is also freely supported. The pressure plate 9 has an annular disc portion 9a having an outer diameter slightly smaller than the cylindrical inner diameter of the clutch outer 4 and is opposed to the clutch center 8, and a cylindrical portion 9b extending from the middle of the disc portion 9a is a clutch output shaft. 2 extends toward the clutch center 8 in parallel.

  A plurality of clutch friction plates 11 on the clutch outer 4 side and clutch plates 10 on the pressure plate 9 side are alternately arranged in a space between the outer peripheral surface of the cylindrical portion 9 b of the pressure plate 9 and the cylindrical inner peripheral surface of the clutch outer 4. It is arranged.

  That is, a plurality of split grooves 4a oriented in the axial direction are formed on the inner peripheral surface of the cylinder of the clutch outer 4 in the circumferential direction, and the outer peripheral protrusions of the clutch friction plate 11 are engaged with the split grooves 4a in the axial direction. On the other hand, a plurality of grooves 9c oriented in the axial direction are formed on the outer peripheral surface of the cylindrical portion 9b of the pressure plate 9 along the circumferential direction, and a clutch plate is formed on the groove 9c. A plurality of sheets are disposed between the clutch friction plates 11 with 10 inner peripheral projections engaged to allow sliding in the axial direction.

  The plurality of clutch friction plates 11 and the clutch plate 10 are sandwiched between the annular disc portion 8 b of the clutch center 8 and the disc portion 9 a of the pressure plate 9. Therefore, when the pressure plate 9 approaches the clutch center 8 and the interval is reduced, the clutch friction plate 11 and the clutch plate 10 approach each other to strengthen the frictional engagement, and conversely, the pressure plate 9 is separated from the clutch center 8 and the interval is increased. When enlarged, the clutch friction plate 11 and the clutch plate 10 are separated from each other to weaken the frictional engagement.

  The annular disk portion 9a of the pressure plate 9 is formed with a concave portion 9d whose center portion is recessed from the outer edge portion on the surface opposite to the cylindrical portion 9b, and three bolt insertion holes at equal intervals in the concave portion 9d. 9e is drilled. A centrifugal weight 42 is pivotally supported at the base end portion of the bolt insertion hole 9e in the recess 9d so as to be swingable by the bolt 31.

  As shown in FIG. 7, in the centrifugal weight 42, the locking arm 42b extends from the base end portion 42a toward the rear side in the rotation direction, and the engaging surface 42c at the distal end portion of the locking arm 42b is the ratchet plate 6. It is formed so that it may engage with. In the centrifugal weight 42, the locking arm 42 b is urged toward the central axis side, that is, the ratchet plate 6 side by a set spring 45 interposed between the centrifugal weight 42 and the pressure plate 9. The centrifugal weight 42 constitutes the restraining member RM together with the ratchet plate 6 and is disposed between the pressure plate 9 and the clutch outer 4 in the axial direction.

  As shown in FIGS. 2 and 3, the annular disc portion 9a of the pressure plate 9 has a clutch lifter support boss 9f extending outwardly around the bolt insertion hole 9e on the surface of the cylindrical portion 9b. Further, a cam groove 9g is formed adjacent to the clutch lifter support boss 9f on the front side in the rotational direction. The cam groove 9g has a groove inclined surface 91 that becomes gradually deeper toward the rear side in the rotation direction, and a pressing surface 92 that is erected from the deepest portion of the cam groove 9g toward the clutch lifter support boss 9f. .

  In addition, the annular disc portion 9a of the pressure plate 9 is provided on the surface facing the clutch center 8 at a regular interval between the clutch lifter supporting boss 9f and the cam groove 9g spaced apart from the clutch lifter supporting boss 9f. A long slot 22 is formed so that a half of a return spring (not shown) can be fitted.

  On the other hand, a through hole 8d through which the clutch lifter support boss 9f of the pressure plate 9 penetrates is formed in the annular disk portion 8b facing the pressure plate 9 of the clutch center 8, and further on the front side in the rotation direction with respect to the through hole 8d. In addition, a cam projection 8e accommodated in the cam groove 9g of the pressure plate 9 is formed adjacently. The cam protrusion 8 e has a protrusion inclined surface 85 that gradually increases in thickness toward the rear side in the rotation direction, and a pressure receiving surface 86 that can come into contact with the pressing surface 92 of the pressure plate 9.

  Further, the annular disc portion 8b of the clutch center 8 has three long grooves 27 at equal intervals between the through hole 8d and the cam projection 8e spaced from the through hole 8d on the surface facing the pressure plate 9. A half body of a return spring (not shown) is formed.

  Returning to FIG. 1, a clutch lifter 32 provided close to the tip of the clutch output shaft 2 has a bearing 33 as a release operating portion fitted on the inner peripheral side, and three flange lifters 32 a of the clutch lifter 32 have three flanges 32 a. The tips of the clutch lifter support bosses 9f are in contact with each other. The bolt 31 supports the clutch lifter support boss 9f, the clutch lifter 32, and the centrifugal weight 42 through the same axis and fastened together.

  The clutch lifter 32 is urged in a direction away from the clutch center 8 (rightward in FIG. 1) by a disc spring 12 which is a clutch spring whose base end is locked to the clutch center 8, so that it is tightened together with a bolt 31. The pressed pressure plate 9 is biased in a direction approaching the clutch center 8 (right direction in FIG. 1).

  The clutch lifter support boss 9f that passes through the through hole 8d of the clutch center 8 is movable along the through hole 8d. Therefore, the relative rotation of the pressure plate 9 with respect to the clutch center 8 causes the clutch lifter support boss 9f to pass through the through hole 8d. The stopper mechanism is configured to be restricted to the range that can be moved.

  A return spring is interposed between the long groove 22 on the pressure plate 9 side and the long groove 27 on the clutch center 8 side so as to be contracted in the circumferential direction. When is advanced in the direction of rotation, it is biased in the direction to return it to its original state. In addition, the arrow of FIGS. 3-7 has shown the rotation direction.

  The ratchet plate 6 that is spline-fitted to the clutch output shaft 2 together with the clutch center 8 is formed with three locking projections 6b that bulge outward in the radial direction around the fitting portion 6a, and the rotation direction of the locking projection 6b. On the front side, a receiving portion 6c that contacts the engaging surface 42c of the centrifugal weight 42 is formed. The engaging surface 42c is an arc surface, and the receiving portion 6c is in contact with the flat surface.

  Since the locking arm 42b of the centrifugal weight 42 is in the same position in the axial direction as the ratchet plate 6, when it is stopped, it is biased toward the ratchet plate 6 by the spring force of the set spring 45, and the engagement surface 42c. And the receiving portion 6c are in contact with each other. Further, when rotating at a predetermined rotational speed or more, the locking arm 42b of the centrifugal weight 42 abuts against the wall surface of the disk portion 9a that defines the concave portion 9d of the pressure plate 9, and the swinging of the centrifugal weight 42 is restricted. It is supposed to be.

  A limiter cancellation mechanism LC is constituted by a combination of the centrifugal weight 42 and the ratchet plate 6 and the like. When the pressure plate 9 is stopped or when the idling speed is less than the predetermined number of revolutions, the centrifugal weight 42 is ratchet by the set spring 45. With the pressure plate 9 pressed against the plate 6 side and the pressure plate 9 most advanced in the rotational direction, the locking arm 42b is in contact with and engaged with the receiving portion 6c as shown by the solid line in FIG. The relative rotation of the ratchet plate 6 with respect to 9 is restricted.

  The centrifugal weight 42 is integrated with the pressure plate 9 via the clutch lifter 32 and the clutch lifter support boss 9f, and the clutch center 8 is integrated with the ratchet plate 6 via the clutch output shaft 2, so that the pressure plate 9 is in the above state. On the other hand, the clutch center 8 is prohibited from rotating relative to the pressure plate 9 and the clutch center 8 is located closest to the pressure plate 9 so that the clutch engagement state is maintained. Is transmitted to the clutch input gear 5 through the friction clutch 1 without any slippage.

  Therefore, in the kick start, the rotational torque of the clutch output shaft 2 that rotates at the start of the push is transmitted to the clutch input gear 5 with a slight power loss, and is transmitted from the clutch input gear 5 to the engine crankshaft to start the engine. It can be done smoothly.

  When the pressure plate 9 has a rotational speed equal to or higher than the idling predetermined rotational speed, the set spring 45 cannot resist the outward swinging of the centrifugal weight 42 due to centrifugal force, and the centrifugal weight 42 is Since it swings and the engagement of the locking arm 42b with the locking projection 6b of the ratchet plate 6 is released, the relative rotation between the pressure plate 9 and the clutch center 8 becomes free.

  5 and 6 are front views of the pressure plate 9 viewed from the clutch center 8 side, and the relative position of the clutch center 8 is indicated by a dotted line, and the clutch center 8 of FIGS. 5 and 6 is shown. Is the state in which the clutch center 8 of FIG. 4 is inverted. FIG. 5 shows a state during normal traveling or acceleration, and FIG. 6 shows a state during deceleration.

  During normal running, the driven clutch center 8 is delayed compared to the driving pressure plate 9, and the cam groove 9g formed in the pressure plate 9 is pressed as shown in FIGS. 5 (a) and 5 (b). The surface 92 pushes the pressure receiving surface 86 of the cam projection 8e formed on the clutch center 8 to rotate the clutch center 8 integrally, and the cam projection 8e is at the deepest position of the cam groove 9g.

  Therefore, the clutch center 8 is located closest to the pressure plate 9, and the distance between the annular disc portion 8b of the clutch center 8 and the disc portion 9a of the pressure plate 9 is reduced to reduce the clutch friction plate 11 and the clutch plate. The clutch engagement state is made strong by frictional engagement with the clutch 10, and the drive of the clutch input gear 5 is transmitted to the clutch output shaft 2 with a slight power loss.

  Until the vehicle is decelerated or until the vehicle is stopped, reverse torque is applied to the friction clutch 1 by the engine brake, and the clutch center 8 integrated with the clutch output shaft 2 precedes the pressure plate 9 on the engine side in the rotational direction. 6A and 6B, the pressure receiving surface 86 of the cam projection 8e formed on the clutch center 8 against the spring load of the return spring is pressed against the cam groove 9g formed on the pressure plate 9. The clutch center 8 is axially pressed against the disc spring 12 by the groove inclined surface 91 which advances relatively with respect to the surface 92 and moves relative to the rotational direction front side of the cam groove 9g and gradually becomes shallow. Generates a resisting clutch release load.

  Therefore, the gap between the annular disc portion 8b of the clutch center 8 and the disc portion 9a of the pressure plate 9 can be increased to weaken the frictional engagement between the clutch friction plate 11 and the clutch plate 10 and to properly slide the clutch. it can. Thus, the torque limiter mechanism TL is constituted by the combination of the cam groove 9g and the cam projection 8e, etc., and it is possible to reduce excessive reverse torque from acting on the clutch input gear 5 and being applied to the engine side, thereby preventing excessive rotation. . Conversely, the engine brake can be prevented from being too effective.

  As described above, when the engine is rotating at a predetermined idling speed or higher, the engagement between the centrifugal weight 42 and the ratchet plate 6 is released, and the relative rotation between the clutch center 8 and the pressure plate 9 is free and torque. The limiter mechanism works to prevent engine overspeed and engine brake effect.

  When the clutch is disengaged, the clutch lifter 32 is pushed into the clutch output shaft 2 side and the pressure plate 9 is moved away from the clutch center 8 against the disc spring 12 via the clutch lifter support boss 9f. The friction engagement between the friction plate 11 and the clutch plate 10 can be released and the clutch can be disconnected. At this time, the relative movement in the axial direction is free even if the ratchet plate 6 and the centrifugal weight 42 are engaged. In the structure of this embodiment, the reverse torque of the clutch output shaft 2 can start the engine, so that it is not necessary to provide a special torque transmission idle gear for kick start.

  As described above, according to the present embodiment, since the restraining member RM including the centrifugal weight 42 and the ratchet plate 6 is disposed between the pressure plate 9 and the clutch outer 4, the friction clutch 1 is moved in the axial direction. It can be formed compactly.

  Further, since the centrifugal weight 42 is fastened to the pressure plate 9 together with the clutch lifter 32, it is not necessary to provide a separate fastening member for fastening the centrifugal weight 42, the number of parts can be reduced, and a space for the torque limiter mechanism TL is secured. can do.

  The pressure plate 9 and the clutch center 8 are preferably made of aluminum. As a result, the cam groove 9g of the pressure plate 9 constituting the torque limiter mechanism TL is formed directly on the pressure plate 9 itself, and the cam protrusion 8e of the clutch center 8 is formed directly on the clutch center 8 itself. In order to ensure, it becomes large compared with the case of manufacturing with iron, but as described above, the space of the torque limiter mechanism TL is secured, so that the friction clutch 1 can be reduced in weight while securing the necessary rigidity.

  Further, when the cam protrusion 8e is formed directly on the clutch center 8 itself, the pressure receiving surface 86 of the cam protrusion 8e is preferably connected without a step from the wall surface of the through hole 8d adjacent to the cam protrusion 8e. Thereby, the stress concentration which arises in a level | step-difference part can be avoided, and durability can be improved. Similarly, when the cam groove 9g is formed directly on the pressure plate 9 itself, the pressing surface 92 of the cam groove 9g is connected without a step from the clutch lifter support boss 9f adjacent to the cam groove 9g or the surrounding thick portion. It is preferable. Thereby, the stress concentration which arises in a level | step-difference part can be avoided, and durability can be improved.

  Further, the pressure plate 9 has a concave portion 9d whose central portion is recessed from the outer edge portion on the side where the constraining member RM is disposed, and the constraining member RM is disposed in the concave portion 9d. Can be made more compact.

  Furthermore, since the engaging surface 42c of the centrifugal weight 42 is an arc surface and the receiving portion 6c of the ratchet plate 6 is in contact with a flat surface, it is possible to absorb variations such as crossing dimensions and mounting errors. Thus, each centrifugal weight 42 and the locking projection 6b can be reliably brought into contact with each other to transmit torque.

  In addition, this invention is not limited to what was illustrated to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.

1 Friction clutch 2 Clutch output shaft (clutch output member)
4 Clutch outer 5 Clutch input gear (clutch input member)
6 Ratchet plate (engagement member)
8 Clutch center 9 Pressure plate 9d Recess 32 Clutch lifter 42 Centrifugal weight LC Limiter cancellation mechanism RM Restraining member TL Torque limiter mechanism

Claims (4)

A friction clutch (1) for connecting and disconnecting power transmission between the clutch input member (5) and the clutch output member (2) by expanding and contracting the distance between the clutch center (8) and the pressure plate (9). There,
A clutch outer (4) having a bottomed cylindrical shape and rotatably supported by the clutch output member (2);
A torque limiter mechanism (TL) that moves the pressure plate (9) in a direction to increase the distance from the clutch center (8) by inputting torque from the clutch output member (2);
When the rotational speed of the clutch center (8) is equal to or lower than the rotational speed during idling, the restraining member (RM) restrains the relative displacement in the rotational direction of the pressure plate (9) relative to the clutch center (8) in one direction. A limiter cancellation mechanism (LC),
The pressure plate (9) is housed inside the clutch outer (4),
A friction clutch (1), wherein the restraining member (RM) is disposed between the pressure plate (9) and the clutch outer (4). A friction clutch (1) according to claim 1,
The restraining member includes a centrifugal weight (42) and an engagement member (6) that engages with the centrifugal weight (42) when the clutch output member (2) is not more than a predetermined rotation.
The frictional clutch (1), wherein the centrifugal weight (42) is fastened together with the clutch lifter (32) to the pressure plate (9). A friction clutch (1) according to claim 2,
The pressure plate (9) and the clutch center (8) are both made of aluminum,
The torque limiter mechanism (TL) is a friction clutch (1) formed directly on the pressure plate (9) and the clutch center (8) itself. The friction clutch (1) according to any one of claims 1 to 3,
The pressure plate (9) has a recess (9d) whose center is recessed from the outer edge on the side where the restraining member (RM) is disposed,
The friction clutch (1), wherein the restraining member (RM) is disposed in the recess (9d).

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