JP2007205387A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission device for surely gaining a cam property as targeted when forming one cam face and the other cam face of a pressure contact assist cam or a back torque limiter cam on the peripheral edge of a clutch member and on a pressure member, respectively, if setting the width of each cam face to be greater or using it for a long period. <P>SOLUTION: The power transmission device comprises a clutch housing 2, a plurality of driving side clutch plates 6, a plurality of driven side clutch plates 7 for pressure contact with or separation from the driving side clutch plates 6, an approximately cylindrical clutch member 4, a pressure member 5, and the pressure contact assist cam or the back torque limiter cam. One cam faces 11a, 11b and the other cam faces 12a, 12b constituting the pressure contact assist cam or the back torque limiter cam are formed as separate members 11, 12 of hard materials such as iron or titanium and fixed thereto. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power transmission device that can arbitrarily transmit or block the rotational force of an input member to an output member.

  In general, a power transmission device included in a motorcycle is used to arbitrarily transmit or cut off the driving force of an engine to and from a driving wheel. An input member connected to the engine side, and the transmission and driving wheel side And an output member connected to the output member, and a clutch member connected to the output member. The transmission of the power is cut off by releasing the pressure contact force.

  However, a pressure assist function that improves the pressure contact force of both clutch plates during power transmission, and a back torque limiter that separates both clutch plates when a so-called back torque is generated when the rotation of the output member exceeds the rotation speed of the input member. In order to add a function, for example, as disclosed in Patent Document 1, a cam is disclosed. The power transmission device in this document includes two cams each having a slope surface (cam surface) formed on the pressure plate and the clutch center.

During normal power transmission, the pressure plate is moved in a direction in which the driving side clutch plate and the driven side clutch plate are strongly pressed by one cam (pressure contact assist cam), while when the back torque is generated, The other cam (back torque limiter cam) can absorb the back torque by moving the pressure plate in the direction in which the pressure contact between both clutch plates is released.
Japanese Patent Laid-Open No. 2-150517

  However, in the above-described conventional power transmission device, one cam surface of the pressure-contact assist cam or the back torque limiter cam is formed along the periphery of the clutch member, and the other cam is opposed to the one cam surface. When trying to form the surface on the pressure plate, there were the following problems.

  As shown in FIG. 6, when one cam surface A is formed by cutting out the peripheral edge 101a of the clutch member 101, the difference between the inner diameter side dimension a and the outer diameter side dimension b increases as the width t increases. Therefore, the inclination angle is different between the inner diameter side and the outer diameter side of one cam surface A. That is, when the other cam surface B formed on the pressure plate 102 is slid on one cam surface A, the other cam surface B slides closer to the inner diameter side of the one cam surface A due to mutual tolerance. And when sliding near the inner diameter side of one cam surface A, the inclination angle of the cam surface (on the paper surface in FIG. 6B). On the other hand, when the slider slides closer to the outer diameter side, the cam surface inclination angle (the same) becomes a large cam characteristic.

  For this reason, when the width t of the cam surface is set large in order to reduce the surface pressure applied to the cam surface, there is a problem that it becomes difficult to obtain the targeted cam characteristics. In addition, since the clutch member and the pressure plate of the power transmission device are usually made of an aluminum molded product, when the cam surface is formed on these members, the cam surface is worn away in the process of using the power transmission device. There is a possibility that the cam characteristic may be different from the characteristic.

  The present invention has been made in view of such circumstances, and when the one cam surface and the other cam surface of the press-contact assist cam or the back torque limiter cam are respectively formed on the periphery of the clutch member and the pressure member, It is an object of the present invention to provide a power transmission device that can reliably obtain targeted cam characteristics even when the width of the cam surface is set to be large or used for a long time.

  The invention according to claim 1 is formed alternately with a clutch housing that rotates together with the input member, a plurality of drive side clutch plates that are formed in the clutch housing and can rotate with the clutch housing, and the drive side clutch plates. A plurality of driven-side clutch plates that can be pressed against or separated from the driving-side clutch plate; a substantially cylindrical clutch member that is formed on a side surface of the driven-side clutch plate and connected to an output member; and the driven-side clutch A pressure member capable of arbitrarily pressing or separating the plate and the driving side clutch plate, and the driving side clutch plate and the driven side clutch when the rotational force input to the input member can be transmitted to the output member A pressure assist cam for increasing the pressure contact force with the plate or the drive side clutch when the rotation of the output member exceeds the rotation speed of the input member. In the power transmission device comprising a back torque limiter cam for separating the clutch plate and the driven side clutch plate, one of the cam surfaces constituting the pressure contact assist cam or the back torque limiter cam and the one of the cam surfaces The other cam surface facing the cam surface is formed as a separate member made of a material harder than the clutch member and the pressure member while being extended to the periphery of the clutch member and the pressure member, respectively. The clutch member and the pressure member are fixed respectively.

  According to a second aspect of the present invention, in the power transmission device according to the first aspect, the separate member is fixed by insert molding when the clutch member or the pressure member is molded.

  According to a third aspect of the present invention, in the power transmission device according to the first or second aspect, at least one of the cam surfaces is formed with a crowning in the extending direction or the width direction.

  According to a fourth aspect of the invention, in the power transmission device according to any one of the first to third aspects, the separate member is made of iron or titanium.

  According to the first aspect of the present invention, the one cam surface constituting the press-contact assist cam or the back torque limiter cam and the other cam surface facing the one cam surface are respectively provided on the periphery of the clutch member and the pressure member. While being formed as a separate member made of a material harder than the clutch member and the pressure member, the separate member is fixed to the clutch member and the pressure member, respectively, so that the width of the cam surface is set large, or The targeted cam characteristics can be reliably obtained even after long-term use.

  According to the invention of claim 2, since the separate member is fixed by insert molding at the time of molding the clutch member or the pressure member, the assembly accuracy between the separate member and the clutch member or the pressure member can be improved, A stronger fixation can be achieved.

  According to the third aspect of the present invention, at least one of the cam surfaces is formed with a crowning in the extending direction or the width direction, so that uneven wear of the cam surface is suppressed particularly in the initial use of the power transmission device. Can do.

  According to the invention of claim 4, since the separate member is made of iron or titanium, it is possible to reliably avoid wear of the cam surface in the process of using the power transmission device.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
The power transmission device according to the present embodiment is disposed in a vehicle such as a two-wheeled vehicle and arbitrarily transmits or shuts off the driving force of the engine to the mission or driving wheel side. As shown in FIG. A clutch housing 2 in which a gear 1 as a member is formed, a clutch member 4 connected to a shaft 3 as an output member, a pressure member 5 attached to the right end side of the clutch member 4 in the figure, a clutch housing The drive side clutch plate 6 connected to the second side, the driven side clutch plate 7 connected to the clutch member 4 side, the engagement member 12a, and the second engagement member 12b are mainly configured.

  The gear 1 is rotatable about the shaft 3 when a driving force (rotational force) transmitted from the engine is input, and is connected to the clutch housing 2 by a rivet 8 or the like. The clutch housing 2 is formed of a cylindrical case member opened on the right end side of the figure, and a plurality of drive side clutch plates 6 are formed from the inner peripheral wall thereof. Each of the 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 the figure). Yes.

  The clutch member 4 is formed of a cylindrical case member disposed in the clutch housing 2 and opened on the right end side in the figure. The shaft 3 is connected to the substantially center of the clutch member 4 by spline fitting while passing therethrough, and the shaft 3 is also rotated when the clutch member 4 rotates. A spline 10 extending in the axial direction (left-right direction in the figure) is formed on the outer peripheral side surface of the clutch member 4, and the driven clutch plate 7 is fitted into the spline 10.

  More specifically, as shown in FIG. 2, the spline 10 formed on the clutch member 4 is configured to have a concavo-convex shape integrally formed over substantially the entire circumference of the outer peripheral side surface thereof. When the driven clutch plate 7 is fitted into the concave groove 10, the movement of the driven clutch plate 7 in the rotational direction is restricted while allowing the movement of the driven clutch plate 7 in the axial direction with respect to the clutch member 4. It is configured to be able to rotate.

  The driven clutch plates 7 are alternately stacked with the driving clutch plates 6 so that the adjacent clutch plates 6 and 7 can be pressed against or separated from each other. That is, both the clutch plates 6 and 7 are allowed to slide in the axial direction of the clutch member 4 and are pressed against each other when pressed by the pressure member 5 in the left direction in FIG. Is transmitted to the clutch member 4 and the shaft 3, and when the pressure member 5 releases the pressure, the clutch member 4 stops and stops following the rotation of the clutch housing 2, and transmits the rotational force to the shaft 3. Will not be done.

  The separation of the clutch plates 6 and 7 here does not have to be a state in which a clearance is generated between the clutch plates 6 and 7, and the pressure contact force is not required even if a physical clearance is not generated. It also includes a state where the clutch member 4 is released and does not follow the rotation of the clutch housing 2 (that is, a state where the drive side clutch plate 6 slides on the driven side clutch plate 7).

  The pressure member 5 is formed in a substantially disc shape so as to close the opening (right end in the figure) of the clutch member 4, and is always urged leftward in the figure by the clutch spring S. That is, the clutch member 4 is formed with a boss portion 4b extending and penetrating to the pressure member 5 side. The clutch bolt B is inserted into the boss portion 4b and the head side of the clutch bolt B and the pressure member 5 are inserted. Since the clutch spring S is interposed between the pressure member 5 and the pressure member 5, the pressure member 5 is always urged leftward.

  On the other hand, the edge surface 5a of the pressure member 5 is in contact with the one of the stacked drive side clutch plates 6 that is closest to the pressure member 5 (the rightmost portion in the figure), and the clutch spring S The pressure member 5 that has obtained the urging force presses the rightmost drive side clutch plate 6 so that the clutch plates 6 and 7 come into pressure contact with each other. Accordingly, the clutch housing 2 and the clutch member 4 are always connected, and the shaft 3 can be rotated when a rotational force is input to the gear 1.

  However, a push rod 9 extending in the axial direction is disposed inside the shaft 3, and when the driver operates an operating means (not shown), the push rod 9 protrudes to the right in the figure, The pressure member 5 can be moved rightward against the urging force of the clutch spring S. When the pressure member 5 moves to the right, the pressure contact force between the drive side clutch plate 6 and the driven side clutch plate 7 is released, and the rotational force input to the gear 1 and the clutch housing 2 enters the clutch member 4 in a separated state. And it is interrupted without being transmitted to the shaft 3. The pressure member 5 is configured so that the driving side clutch plate 6 and the driven side clutch plate 7 can be pressed against or separated from each other as the clutch member 4 moves in the axial direction.

  Furthermore, as shown in FIG. 2, one other member 11 having one cam surface 11a, 11b formed on its peripheral edge 4a is fixed to the clutch member 4 according to the present embodiment. The one other member 11 is made of a material (iron, titanium, or the like) harder than the clutch member 4 made of an aluminum molded product, and the upper surface 11c of the clutch member 4 is substantially the same as the peripheral edge 4a of the clutch member 4 when cast. It is fixed by insert molding at the same position. As a result, the cam surfaces 11 a and 11 b are extended at the peripheral edge 4 a of the clutch member 4.

  On the other hand, as shown in FIG. 3, the pressure member 5 has the other cam surface 12a, 12b facing the one cam surface 11a, 11b in the state of being assembled to the clutch member 4, and the other separate member 12. Is fixed. The other separate member 12 is made of a material (iron, titanium, or the like) harder than the pressure member 5 made of an aluminum molded product. When the pressure member 5 is cast, the other member 12 is protruded from the pressure member 5 by insert molding. It is fixed.

  Thus, in a state where the pressure member 5 is assembled to the opening end side (periphery 4a side) of the clutch member 4, one cam surface 11a and the other cam surface 12a are matched to constitute a back torque limiter cam. The one cam surface 11b and the other cam surface 12b are matched to form a pressure-contact assist cam.

  Then, when the rotational force input to the gear 1 and the clutch housing 2 can be transmitted to the shaft 3 via the clutch member 4, the rotational force in the direction a in FIG. Therefore, the pressure member 5 generates a force in the direction c in the drawing by the action of the pressure-contact assisting cam constituted by the one cam surface 11b and the other cam surface 12b, and the drive side clutch plate 6 And the driven clutch plate 7 (including the engaging member 12a and the second engaging member 12b) are increased in pressure.

  On the other hand, when the rotation of the shaft 3 exceeds the rotation speed of the gear 1 and the clutch housing 2 and a back torque in the direction b in FIG. 5 is generated, the cam surface 11a and the other cam surface 12a are formed. Due to the action of the back torque limiter cam, the pressure member 5 is moved in the direction d in the figure, and the drive side clutch plate 6 and the driven side clutch plate 7 (including the engagement member 12a and the second engagement member 12b). Separation is performed. Thereby, the malfunction with respect to the power transmission device and power source (engine side) by back torque can be avoided.

  According to the power transmission device, the cam surfaces 11a and 11b and the other cam surfaces 12a and 12b constituting the press-contact assist cam and the back torque limiter cam are formed on the separate members 11 and 12, respectively. Since the separate members 11 and 12 are made of a material harder than the clutch member 4 or the pressure member 5, wear of the cam surface due to the sliding action can be suppressed. Therefore, even if the cam surface width is set large or the cam surface is used for a long time, the targeted cam characteristics can be obtained with certainty.

  Further, since the separate members 11 and 12 are fixed by insert molding when the clutch member 4 and the pressure member 5 are molded, the assembly accuracy between the separate members 11 and 12 and the clutch member 4 or the pressure member 5 can be improved. In addition, it is possible to make a stronger fixation. Furthermore, since the separate members 11 and 12 are made of a relatively hard material such as iron or titanium, it is possible to reliably avoid wear of the cam surface during the use of the power transmission device.

  Although the present embodiment has been described above, the present invention is not limited thereto. For example, the width direction (clutch member) of one of the cam surfaces 11a and 11b or the other cam surfaces 12a and 12b (4 radial direction) or the extending direction may be formed. The crowning in this case has a shape in which one cam surface 11a, 11b (the same applies to the other cam surfaces 12a, 12b) is gradually expanded from both ends in the width direction or the extending direction toward the center.

  In addition, in either one of the cam surfaces 11a and 11b or the other cam surfaces 12a and 12b, a crowning may be formed in both the width direction and the extending direction so that the approximate center of the cam surface bulges. Good. In this way, if the crowning is formed in the extending direction or the width direction on at least one of the cam surfaces, uneven wear of the cam surface can be suppressed particularly in the initial use of the power transmission device.

  Further, the fixing method of the separate member 11 having one cam surface 11a, 11b or the separate member 12 having the other cam surface 12a, 12b to the clutch member 4 or the pressure member 5 is as in this embodiment. It is not limited to the insert-molded one, and may be fixed by, for example, bolt tightening, fitting, press-fitting or the like. The separate members 11 and 12 need only be harder than the clutch member 4 or the pressure member 5 and may be made of a material other than iron or titanium.

  Furthermore, the present invention may be applied to a structure in which only one of the pressure contact assist cam and the back torque limiter cam is formed between the clutch member and the pressure member. The power transmission device according to the present invention can be applied to various multi-plate clutch type power transmission devices such as two-wheeled vehicles, automobiles, three-wheel or four-wheel buggies, and general-purpose machines.

  One of the cam surfaces constituting the press-contact assist cam or the back torque limiter cam and the other cam surface facing the one cam surface are extended to the periphery of the clutch member and the pressure member, respectively. As long as the power transmission device is formed as a separate member made of a material harder than the member, and the separate member is fixed to the clutch member and the pressure member, the power transmission device to which other functions are added or the external shape is different. It can also be applied to things.

The longitudinal cross-sectional view which shows the power transmission device which concerns on embodiment of this invention The perspective view which shows the clutch member in the power transmission device The perspective view which shows the pressure member in the same power transmission device Schematic diagram showing the action of the pressure-assist assist cam during forward rotation of the clutch member in the power transmission device The schematic diagram which shows the effect | action of the cam for back torque limiters at the time of reverse rotation of the clutch member in the power transmission device (a state where the back torque is applied). It is a schematic diagram for demonstrating the malfunction of the cam surface in the conventional power transmission device, (a) Cross-sectional schematic diagram (b) Plane schematic diagram

Explanation of symbols

1 Gear (input member)
2 Clutch housing 3 Shaft (output member)
4 Clutch member 5 Pressure member 6 Drive side clutch plate 7 Driven side clutch plate 8 Rivet 9 Push rod 10 Spline 11 One separate member 11a, 11b One cam surface 12 The other separate member 12a, 12b The other cam surface S Clutch spring B Clutch bolt

Claims (4)

A clutch housing that rotates with the input member;
A plurality of drive side clutch plates formed in the clutch housing and capable of rotating together with the clutch housing;
A plurality of driven side clutch plates formed alternately with the driving side clutch plates and capable of being pressed against or separated from the driving side clutch plates;
The driven clutch plate is formed on the side surface, and a substantially cylindrical clutch member connected to the output member;
A pressure member capable of arbitrarily press-contacting or separating the driven-side clutch plate and the driving-side clutch plate;
A pressure assisting cam for increasing the pressure contact force between the drive side clutch plate and the driven side clutch plate when the rotational force input to the input member can be transmitted to the output member; A back torque limiter cam for separating the drive side clutch plate and the driven side clutch plate when the rotation exceeds the rotation number of the input member;
In the power transmission device comprising:
One of the cam surfaces constituting the pressure-contact assist cam or the back torque limiter cam and the other cam surface facing the one cam surface are extended to the peripheral edge of the clutch member and the pressure member, respectively. And a separate member made of a material harder than the pressure member, and the separate member is fixed to the clutch member and the pressure member, respectively.   The power transmission device according to claim 1, wherein the separate member is fixed by insert molding when the clutch member or the pressure member is molded.   The power transmission device according to claim 1, wherein at least one of the cam surfaces is formed with a crowning in an extending direction or a width direction thereof.   The power transmission device according to any one of claims 1 to 3, wherein the separate member is made of iron or titanium.

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