JP2009287680A - Reverse-input preventing clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize clutch operation for a long time by restricting wear with unlock operation of an output side member, in regard to a reverse-input preventing clutch which locks the output side member relative to the reverse-input torque. <P>SOLUTION: In such a state that a roller 10 pushed by a holder support 9a moves to a wide part of a wedge-like space 14 to unlock an inner ring 3, tangential lines A and B in contact positions of the roller 10 with an outer ring 6 and an inner ring 3 are drawn, and the holder support 9a is brought in contact with the roller 10 on an outer ring 6 side of a straight line L connecting an intersection C of both the tangential lines A and B and the center O of the roller 10 to strongly push the roller 10 to the inner ring 3 so that friction force between the inner ring 3 and the roller 10 becomes larger than friction force between the outer ring 6 and the roller 10. With this structure, the roller 10 slides relative to the inner peripheral cylindrical surface of the outer ring 6, and rolls on an inner ring cam surface 3a, and wear of a contact part of the inner ring 3 with the roller 10 can be restricted. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reverse input prevention clutch that transmits rotation of an input side member to an output side member and prevents rotation of the output side member from being transmitted to the input side member.

The reverse input prevention clutch connects the input side member and the output side member that rotate about the same axis so that torque can be transmitted, and the reverse input prevention mechanism, that is, the normal side of the input side member to which torque is input is connected to the connecting portion. A mechanism is provided in which rotation in both reverse directions is transmitted to the output side member, and rotation of the output side member due to reverse input torque is not transmitted to the input side member. Such a reverse input prevention clutch includes a type that locks the output side member when reverse input torque is applied to the output side member (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2007-232095

  FIG. 1 and FIG. 2 show an example of a reverse input prevention clutch that locks the output side member against the reverse input torque as described above. This clutch connects an input shaft (input side member) 1 and an output side member 4 so as to rotate around the same axis and transmit torque, and to the outside of the inner ring 3 forming a part of the output side member 4. The outer ring 6 is provided with a fixed outer ring 6, and cam surfaces 3 a are provided on the outer circumference of the inner ring 3 such that the inclination is alternately reversed in the circumferential direction. A plurality of wedge-shaped spaces 14 that are gradually narrowed on both sides in the direction are formed, and column portions 9a of the cage 9 that rotate integrally with the input shaft 1 are inserted on both sides in the circumferential direction of each wedge-shaped space 14, and a pair of each wedge-shaped space 14 is paired. The cylindrical roller (rolling element) 10 and the compression coil spring (elastic member) 11 for pushing each roller 10 into the narrow portion of the wedge-shaped space 14 are incorporated.

  In this clutch, each roller 10 is pushed into the narrow portion of the wedge-shaped space 14 by the elastic force of the spring 11, so that the roller 10 on the rear side in the rotational direction can be moved to the outer ring 6 even when reverse input torque is applied to the output side member 4. By engaging with the inner ring 3, the inner ring 3 is locked, and the input shaft 1 does not rotate.

  On the other hand, when an input torque is applied to the input shaft 1, the column portion 9 a of the cage 9 rotates integrally with the input shaft 1, and the roller 10 on the rear side in the rotation direction resists the elasticity of the spring 11 to form a wedge-shaped space 14. , The engagement between the roller 10 and the outer ring 6 and the inner ring 3 is released, the inner ring 3 is released from the locked state, and the rotation of the input shaft 1 is transmitted to the output side member 4.

  By the way, when the input torque and the reverse input torque are simultaneously applied to the reverse input prevention clutch of the above-described method in the same direction, the outer ring and the inner ring are kept in a state where the rollers on the rear side in the rotation direction are always pushed by the pillar portion of the cage. The engagement and release of the inner ring are repeated, and the inner ring is locked and unlocked continuously. At the time of unlocking, if the contact force between the roller and the outer ring is stronger than the contact force with the inner ring, the roller usually rolls on the inner peripheral surface of the outer ring and slips with a certain part of the inner ring cam surface. Parts that come into contact with the rollers may cause premature wear. If the wear of the contact portion of the inner ring with the roller increases, the inner ring cannot be locked or the inner ring cannot be unlocked, and the clutch operation tends to become unstable.

  SUMMARY OF THE INVENTION An object of the present invention is to suppress wear associated with unlocking of an output side member and stabilize the clutch operation for a long period of time in a reverse input prevention clutch that locks an output side member against reverse input torque.

  In order to solve the above-described problems, the present invention provides a torque for transmitting the rotation of the input side member to the output side member with a slight angular delay between the input side member and the output side member rotating around the same axis. A transmission member is provided, and a fixing member having a cylindrical surface on the inner peripheral side or the outer peripheral side is arranged so that the cylindrical surface faces the outer peripheral surface or the inner peripheral surface of the output side member. And a cam surface that forms a wedge-shaped space gradually narrowing in the circumferential direction between the fixing member and the cylindrical surface of the fixing member, and is connected to the input member between the output member and the fixing member. While inserting the pillar portion of the cage, rolling elements are arranged in each wedge-shaped space, and an elastic member is incorporated at a predetermined position between these rolling elements to push each rolling element into the narrow portion of the wedge-shaped space. When the input side member rotates, the input side In the reverse input prevention clutch in which the pillar portion of the cage that rotates integrally with the material pushes the rolling element to the wide part of the wedge-shaped space against the elastic force of the elastic member so that torque is transmitted to the output side member. When the pillar portion of the cage pushes the rolling element, the rolling element slides with respect to the cylindrical surface of the fixed member and rolls on the cam surface of the output side member.

  That is, the rolling element pressed by the pillar portion of the cage moves to the wide portion of the wedge-shaped space, the engagement between the rolling element, the fixing member, and the output side member is released, and the output side member is released from the locked state. Sometimes, the rolling element rolls on the cam surface of the output side member, so that the wear of the contact portion between the output side member and the rolling element can be suppressed.

  Means for allowing the rolling element to slide with respect to the cylindrical surface of the fixed member and roll on the cam surface of the output member is a contact position between the rolling member and the cylindrical surface of the fixed member and the cam surface of the output member. The tangent line is drawn, and the contact position between the retainer column and the rolling element is arranged on the cylindrical surface side of the fixing member with respect to the straight line connecting the intersection of these tangents and the center of the rolling element. Can be adopted.

  Further, as another means for causing the rolling element to slide with respect to the cylindrical surface of the fixed member and roll on the cam surface of the output side member, a friction coefficient between the cylindrical surface of the fixed member and the rolling element is determined. It is also possible to employ a material whose coefficient of friction is smaller than the coefficient of friction between the cam surface of the output side member and the rolling element. In the case of this means, the cylindrical surface of the fixing member may be subjected to any surface finish of grinding, mirror polishing or barrel polishing, or shot peening may be applied to the cam surface of the output side member.

  As described above, according to the present invention, in the reverse input prevention clutch that locks the output side member against the reverse input torque, the rolling element rolls on the cam surface of the output side member when the output side member is unlocked, and outputs. Since slippage between the side member and the side member is prevented, the wear of the contact portion between the output side member and the rolling element can be suppressed, and the clutch operation can be stabilized over a long period of time.

  The basic configuration of the reverse input preventing clutch of the first embodiment of the present invention is the same as the conventional one shown in FIGS. 1 and 2 described above. That is, as shown in FIGS. 1 and 2, the reverse input preventing clutch includes an input shaft (input side member) 1, an output side member 4 including an output shaft 2 and an inner ring 3, and a fixed outer ring on the inner periphery of the housing 5. 6 and a fixing member 8 fitted with a presser lid 7, a retainer 9 having a plurality of column portions 9a inserted between the inner ring 3 and the outer ring 6, and a cylinder incorporated between the column portions 9a of the retainer 9. It comprises a roller (rolling element) 10 and a compression coil spring (elastic member) 11.

  In the input shaft 1, an engagement portion 12 formed in a cylindrical shape is inserted into an engagement hole 13 provided in the center of the inner ring 3, and a small-diameter cylindrical portion at the tip is fitted into a hole in the center of the end surface of the output shaft 2. Thus, it rotates around the same axis as the output shaft 2. Here, the engagement hole 13 of the inner ring 3 has substantially the same cross-sectional shape as the engagement portion 12 of the input shaft 1, but is formed so that a slight rotational clearance is generated when the input shaft 1 is inserted. The rotation of the input shaft 1 is transmitted to the output shaft 2 connected to the inner ring 3 with a slight angular delay. The cage 9 is fitted into the engaging portion 12 of the input shaft 1 and rotates integrally with the input shaft 1. And although the output shaft 2 and the inner ring | wheel 3 which were formed in the said output side member 4 are connected so that integral rotation is possible, you may integrally form an output shaft and an inner ring | wheel.

  Further, as shown in FIG. 2, the cam surface 3 a is provided on the outer periphery of the inner ring 3 so that the inclination is alternately reversed in the circumferential direction, and the inner peripheral cylindrical surface of the outer ring 6 and the outer peripheral surface of the inner ring 3 A plurality of wedge-shaped spaces 14 that are gradually narrowed on both sides in the circumferential direction are formed. Then, the pillar portions 9a of the cage 9 are inserted on both sides in the circumferential direction of each wedge-shaped space 14, and a pair of rollers 10 sandwiches springs 11 that push the rollers 10 into the narrow portions of the wedge-shaped space 14 in each wedge-shaped space 14. It is arranged in a state.

  Therefore, even when reverse input torque is applied to the output shaft 2, the roller 10 on the rear side in the rotational direction is pushed into the narrow portion of the wedge-shaped space 14 by the elasticity of the spring 11 and is engaged with the outer ring 6 and the inner ring 3. The inner ring 3 is locked, and the rotation of the output shaft 2 is not transmitted to the input shaft 1.

  On the other hand, when an input torque is applied to the input shaft 1, the column portion 9 a of the cage 9 that rotates integrally with the input shaft 1 opposes the elastic force of the spring 11 against the roller 10 on the rear side in the rotation direction, and the wedge-shaped space 14. Therefore, the engagement between the roller 10 and the outer ring 6 and the inner ring 3 is released, and the inner ring 3 is released from the locked state. When the input shaft 1 further rotates and the engaging portion 12 engages with the engagement hole 13 of the inner ring 3, the rotation of the input shaft 1 is transmitted to the output shaft 2 through the inner ring 3.

  Here, as shown in FIG. 3, when the inner ring 3 is unlocked, the tangent lines A and B at the contact positions between the roller 10 and the inner peripheral cylindrical surface of the outer ring 6 and the cam surface 3a of the inner ring 3 are drawn. Considering a straight line L connecting the intersection C of the tangent lines A and B and the center O of the line 10, the contact position of the retainer 9 with the column portion 9a and the point 10 is on the cam surface 3a side of the inner ring 3. Therefore, the roller 10 is strongly pressed against the inner peripheral surface of the outer ring 6 by the retainer column portion 9a, and the contact force of the outer ring 6 and 10 is larger than the contact force of the inner ring 3 and 10.

  Therefore, when the friction coefficient between the roller 10 and the inner and outer rings 3 and 6 is the same, the friction force (= contact force × friction coefficient) of the outer ring 6 and 10 is larger than the friction force of the inner ring 3 and 10. When the roller 10 pushed by the cage post 9a moves to the wide part of the wedge-shaped space 14, it rolls on the inner peripheral cylindrical surface of the outer ring 6 and slides with respect to the inner ring cam surface 3a. The contact part with is easy to wear.

  Therefore, in this embodiment, the inner ring surface of the outer ring 6 is ground to reduce its surface roughness, and the outer ring 6 is subjected to shot peening on the outer ring surface to increase its surface roughness. The friction coefficient between the inner ring 3 and 10 is made considerably smaller than the friction coefficient between the inner ring 3 and 10, so that the friction force of the outer ring 6 and 10 is smaller than the friction force of the inner ring 3 and 10. As a result, when the roller 10 pushed by the cage column 9a moves to the wide part of the wedge-shaped space 14, it slides on the inner peripheral cylindrical surface of the outer ring 6 and rolls on the inner ring cam surface 3a. Wear of the contact portion between the inner ring 3 and the roller 10 can be suppressed.

  The surface finish of the inner peripheral surface of the outer ring 6 is not limited to grinding, and mirror polishing or barrel polishing can also be employed. However, if the friction coefficient between the outer rings 6 and 10 is too small, the clutch operation may become unstable. Therefore, it is desirable to perform surface finishing so that the friction coefficient is 0.03 or more. Further, only one of the surface finishing of the inner peripheral surface of the outer ring 6 and the shot peening of the outer peripheral surface of the inner ring 3 may be performed.

  This clutch is configured as described above, and when the inner ring 3 is unlocked, the roller 10 rolls on the cam surface 3a of the inner ring 3 so that no slip occurs between the inner ring 3 and the input torque and the reverse input torque. Are simultaneously applied in the same direction and the inner ring 3 is locked and unlocked continuously, the contact portion of the inner ring 3 with the roller 10 is not easily worn, and a stable operation can be obtained over a long period of time.

  FIG. 4 shows a second embodiment. In this embodiment, the column portion 9a of the cage 9 is formed in a substantially fan-shaped cross section, and when the roller 10 is pushed by the cage column portion 9a, the outer ring 6 is in the same line L as described with reference to FIG. The cage post 9a is in contact with the roller 10 on the inner peripheral cylindrical surface side. As a result, the roller 10 is strongly pressed against the cam surface 3a of the inner ring 3, and the contact force of the inner ring 3 and 10 is greater than the contact force of the outer ring 6 and 10. The inner ring surface of the outer ring 6 and the outer ring surface of the inner ring 3 are not subjected to the processing as in the first embodiment, and the friction coefficients between the rollers 10 and the inner and outer rings 3 and 6 are made substantially the same. The configuration of the other parts is the same as that of the first embodiment.

  Therefore, in the clutch of this embodiment, the frictional force of the outer ring 6 and 10 is smaller than the frictional force of the inner ring 3 and 10 as in the first embodiment, and when the inner ring 3 is unlocked, the roller 10 is an inner peripheral cylinder of the outer ring 6. Since it slides on the surface and rolls on the inner ring cam surface 3a, the wear of the contact portion of the inner ring 3 with the roller 10 can be suppressed, and it can be used stably for a long time.

Longitudinal front view of the reverse input preventing clutch of the conventional and the first embodiment Sectional view along line II-II in FIG. Sectional drawing which shows the state at the time of the inner ring | wheel unlocking | release of the clutch of FIG. Sectional drawing which shows the state at the time of the inner ring | wheel unlocking | release of the clutch of 2nd Embodiment.

Explanation of symbols

1 Input shaft (input side member)
2 Output shaft 3 Inner ring 3a Cam surface 4 Output side member 5 Housing 6 Outer ring 7 Presser lid 8 Fixing member 9 Cage 9a Column 10 Roller (rolling element)
11 Spring (elastic member)
12 engaging portion 13 engaging hole 14 wedge-shaped space

Claims (5)

  Torque transmission means for transmitting the rotation of the input side member to the output side member with a slight angular delay is provided between the input side member and the output side member that rotate around the same axis, on the inner peripheral side or the outer peripheral side. A fixing member having a cylindrical surface is arranged so that the cylindrical surface faces the outer peripheral surface or the inner peripheral surface of the output side member, and a predetermined position of the output side member is placed with the cylindrical surface of the fixing member. A cam surface that forms a wedge-shaped space that gradually narrows in the circumferential direction is provided between the output side member and the fixing member, and a pillar portion of the cage connected to the input side member is inserted between the output side member and the fixing member. Each rolling element is arranged in a wedge-shaped space, an elastic member is assembled at a predetermined position between these rolling elements, each rolling element is pushed into a narrow part of the wedge-shaped space, and the input side member is rotated to input. The pillar of the cage that rotates integrally with the side member is In the reverse input prevention clutch in which torque is transmitted to the output side member by pushing the rolling element to the wide part of the wedge-shaped space against the elastic force of the member, the pillar portion of the cage pushes the rolling element. A reverse input preventing clutch characterized in that means for allowing the rolling element to slide with respect to the cylindrical surface of the fixed member and to roll on the cam surface of the output side member is provided.   Means for allowing the rolling element to slide relative to the cylindrical surface of the fixed member and roll on the cam surface of the output side member is at a contact position between the rolling element and the cylindrical surface of the fixed member and the cam surface of the output side member. With respect to a straight line that draws a tangent line and connects the intersection of these tangent lines and the center of the rolling element, the contact position between the retainer column and the rolling element is arranged on the cylindrical surface side of the fixing member. The reverse input preventing clutch according to claim 1.   Means for allowing the rolling element to slide with respect to the cylindrical surface of the fixed member and roll on the cam surface of the output side member is configured to reduce the coefficient of friction between the cylindrical surface of the fixed member and the rolling element. 2. The reverse input prevention clutch according to claim 1, wherein the friction coefficient between the cam surface and the rolling element is smaller than the friction coefficient.   4. The reverse input prevention clutch according to claim 3, wherein the cylindrical surface of the fixing member is subjected to any surface finish of grinding, mirror polishing or barrel polishing.   The reverse input preventing clutch according to claim 3, wherein shot peening is applied to a cam surface of the output side member.

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