JP2008175280A - One-way clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve creep resistance force while utilizing advantages of a shell type outer ring, in a one-way clutch using the shell type outer ring. <P>SOLUTION: In the one-way clutch, pockets 13 including circumferentially slanted cam face 12 are formed on an inner face of the outer ring 11, a roller 14 and a pressing spring 15 of the roller are housed in the pocket 13, a wedge angle θ with a narrower side in a certain direction is formed by the cam face 12 and a shaft 17, and the roller 14 is energized in a narrowing direction of the wedge angle θ by the pressing spring 15. It is composed such that the outer ring 11 is so formed as to comprise an ellipse form in its axial cross-sectional shape, and the cam face 12 is formed within a range including both ends of a major axis X in the inner face of the outer ring 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a one-way clutch used in an office machine or the like.

  The outer ring of a one-way clutch that is formed into a cylindrical shape by deep drawing a sheet of steel is called a shell-type outer ring. Since there is an advantage such as cost, it has been conventionally used in the field of office machines and the like (see Patent Document 1, FIG. 6 and its description).

  The one-way clutch using a shell-shaped outer ring is attached to the mating part (usually the housing of various devices) by press-fitting into the mounting hole provided in the mating part. Since the structure depends only on the force, when the mating part is made of resin, the tightening force is insufficient, and there is a possibility of slippage between the shell outer ring and the mating part due to the transmission torque at the time of locking. For this reason, in the one-way clutch disclosed in Patent Document 1, means for providing an axial rotation-preventing protrusion on a portion corresponding to the cam surface of the inner diameter surface on the outer diameter surface of the outer ring is employed. .

  However, in the case where the above-described means for providing a rotation prevention ridge is adopted, in order to increase the effect of the rotation prevention (that is, to increase the creep resistance), if the height of the ridge is increased, the cam There is a disadvantage that the depth of the surface becomes deeper and the diameter of the roller needs to be increased accordingly, leading to a decrease in the number of rollers.

In order to solve this problem, in the invention of Patent Document 1, in order to increase the creep resistance without reducing the number of rollers, a protrusion for preventing rotation is formed on the outer diameter surface by drawing the steel pipe. The outer ring is made. The outer ring manufactured in this way can prevent the occurrence of slippage due to the presence of the protrusion having a high outer diameter surface even if the counterpart part is made of resin.
JP 2000-213566 (paragraphs 0003 to 0005, FIG. 6)

  However, as described above, the outer ring made by processing the metal tube requires man-hours such as drawing and cutting of the metal tube in the production of the outer ring. In comparison, there is a problem that the processing cost is high.

  Accordingly, an object of the present invention is to provide a one-way clutch having a reliable detent function while taking advantage of the shell-type outer ring.

  In order to solve the above-mentioned problem, in the one-way clutch according to the present invention, as shown in FIGS. 1 and 2, a pocket 13 including a cam surface 12 inclined in the circumferential direction is formed on the inner surface of the outer ring 11, Rollers 14 and presser springs 15 of the rollers 13 are accommodated in the pocket 13, and retaining portions 16, 16 ′ for preventing the rollers 14 and the retainer springs 15 from coming off in the axial direction are provided at both ends of the outer ring 11. . The cam surface 12 and the shaft 17 inserted through the outer ring 11 form a wedge angle θ that narrows in a certain direction, and the pressing spring 15 biases the roller 14 in the direction of narrowing the wedge angle. Basic configuration.

  In such a one-way clutch, the outer ring 11 is formed in an elliptical shape in its axial cross section, and the cam surfaces 12 are formed on both end sides of the major axis X on the inner surface of the outer ring 11. .

  The one-way clutch configured as described above is fitted to the outer diameter surface of the shaft 17 of the apparatus, and the outer ring 11 is press-fitted into an elliptical mounting hole of a counterpart component such as a housing. As indicated by the arrow in FIG. 2, when the shaft 17 rotates relative to the enlargement direction of the wedge angle θ, the shaft 17 idles with respect to the elliptical outer ring 11 and is locked when rotated in the opposite direction.

  The outer ring 11 may have a shell shape, and the retaining portions 16 and 16 'may be formed in a collar shape by bending both ends of the elliptical outer ring 11 inward. Moreover, the structure which the spring receiving part 18 of the said holding | suppressing spring 15 was formed in the edge part by which the wedge angle | corner (theta) of the said pocket 13 becomes the expansion side can be taken.

  Further, as shown in FIG. 5, a conveyance dummy 20 having a cylindrical portion 19 having the same diameter as the shaft 17 is inserted into the outer ring 11 to prevent the rollers 14 and the holding spring 15 from coming off in the inner diameter direction. In some cases, the configuration is intended. The use of such a transport dummy 20 prevents the rollers 14 and the pressing springs 15 from being separated when the one-way clutch is assembled or transported after the assembly is completed, so that it can be transported in a unit state.

  Since the one-way clutch according to the present invention is as described above, the oval outer ring 11 is press-fitted into the oval mounting hole of the mating part 23, so that the mating part 23 is a resin part with a small tightening force. Even in such a case, a large creep resistance is generated and relative slippage is prevented. Further, by making the outer ring 11 into a shell shape, the advantage of the shell type outer ring, that is, the advantage that the sectional height is low and the cost is low for the torque capacity can be obtained.

  Further, the pocket 13 for accommodating the roller 14 and the holding spring 15 is formed by the outer diameter surface of the shaft 17 and the arc surfaces of both ends of the major axis X of the inner surface of the elliptical outer ring 11, so that the roller 14 has a cage. Even if not used, the pocket 13 is held in a stable posture. Therefore, since a cage is unnecessary, the number of parts is small, the structure is simple, and the manufacturing cost can be reduced.

  In addition, when the transfer dummy 20 is used, parts are prevented from being separated during assembly and transfer, which is convenient for transfer in a unit state.

  Hereinafter, embodiments of the one-way clutch according to the present invention will be described.

  The one-way clutch of the embodiment shown in the accompanying drawings comprises a shell-shaped oval outer ring 11, two rollers 14, and a pressing spring 15 corresponding to each roller 14, as shown in FIGS. 1 to 4. The shaft 17 is fitted for use.

  The outer ring 11 is formed by deep drawing a single steel plate, and the cross-sectional shape thereof is a cylinder having a major axis X and a minor axis Y (Y> diameter of shaft 17) as shown in FIG. It is a shape.

  For convenience of explanation, as briefly shown in FIG. 3, the range divided into four by the major axis X and the minor axis Y is divided into the regions I, II, III, IV in the counterclockwise direction based on the minor axis Y. In other words, one cam surface 12 formed on both ends of the major axis X is provided from the region I to II, and the other cam surface 12 is provided from the region III to IV. The one cam surface 12 is formed by a circular arc surface centered at a point P separated from the center point O on the minor axis Y by a certain distance. The end of the area I of the cam surface 12 is indicated by a point a, and the end of the area II is indicated by a point b. The other cam surface 12 is formed at a symmetrical position with respect to the center point O.

  Looking at the major axis X as a reference, the points a and b are in non-target positions, the point a is closer to the major axis X, but the point b is further away. Therefore, a pocket 13 having a shape in which the distance from the shaft 17 is the largest in the vicinity of the end of the major axis X and gradually becomes narrower as the point b is approached. The roller 14 is formed to have a diameter large enough to cause biting at an intermediate portion thereof. A wedge angle θ enlarged toward the point a is formed by the tangent line between the shaft 17 and the cam surface 12 at the biting portion.

  Further, at the end of the pocket 13 in the direction in which the wedge angle θ is enlarged, the spring receiving portion 18 is formed in the axial direction by bending the elliptical outer ring 11 with an L-shaped cross section.

  A roller 14 is accommodated in the pocket 13, and a pressing spring 15 is interposed between the roller 14 and the spring receiving portion 18. The roller 14 can move within the range of the cam surface 12, but the movement to both sides exceeding the range is restricted by the gaps at both ends of the pocket 13.

  As shown in FIG. 4, the holding spring 15 is formed by bending a metal piece into an S shape. The holding spring 15 urges the roller 14 in the narrow direction of the wedge angle θ, and the posture of the roller 14. To stabilize. The rollers 14 maintain a stable posture by the presence of the gaps in the pockets 13 that are gradually narrowed at the outer ends of both ends of the cam surface 12 and the pressing springs 15, so that no cage is required.

  Further, in order to prevent the rollers 14 and the pressing spring 15 from coming off in the axial direction, inward flange-shaped retaining portions 16 and 16 ′ are provided at both ends of the elliptical outer ring 11. Among these, one retaining portion 16 is formed by providing a shaft hole 21 by punching in the central portion of the closed surface generated in the deep drawing process described above. The other retaining portion 16 ′ is formed by pressing the open end portion of the cylindrical material (see the arrow in FIG. 6) after incorporating the roller 14 and the holding spring 15, and the shaft hole 21 ′ is also formed at the same time. It is formed.

  In order to prevent the roller 14 and the holding spring 15 from coming off in the inner diameter direction during assembly and transport of the one-way clutch, a transport dummy 20 having a cylindrical portion 19 having the same diameter as the shaft 17 (see FIGS. 5 and 5). 6). The transfer dummy 20 is a resin molded product, and has a hat shape in which the distal end portion of the cylindrical portion 19 is closed and a collar 22 is formed at the open end of the other end. The collar 22 is inserted into the shaft hole 21 so as to be on the retaining portion 16 side, and the collar 22 is brought into contact with the retaining portion 16. The tip of the cylinder part 19 approaches the inside of the other shaft hole 21 '.

  By inserting the transfer dummy 20 as described above, a pocket 13 similar to the case where the shaft 17 is inserted between the outer diameter surface of the cylindrical portion 19 and the arc surface including the cam surface 12 of the outer ring 11 is formed. The roller 14 and the pressing spring 15 are held in the pocket 13. Thus, the one-way clutch is assembled and transported without parts being separated and disassembled. The transfer dummy 20 and the shaft 17 are replaced when incorporated in the mating part.

  The one-way clutch of the embodiment is as described above, and is attached by press-fitting into an elliptical attachment hole provided in the counterpart component 23 (see FIG. 2). When the shaft 17 rotates in the direction in which the wedge angle θ is enlarged (see the arrow in FIG. 2), the roller 14 moves in the direction in which the wedge angle θ is enlarged, the shaft 17 is idled, and the transmission of torque to the counterpart component 23 is interrupted Is done. When the roller 14 rotates in the opposite direction, the roller 14 moves in the opposite direction and engages with the narrow portion of the wedge angle θ, so that the shaft 17 is locked and torque is transmitted to the counterpart component 23.

  Since the elliptical outer ring 11 is fitted in the elliptical mounting hole of the mating part 23, the one-way clutch exhibits a large creep resistance in the torque transmission.

Sectional view of the one-way clutch of the embodiment Sectional view of the AA line of FIG. Schematic explanatory diagram of FIG. Exploded perspective view of the embodiment Sectional view at the time of conveyance of an example Sectional view during assembly of the embodiment

Explanation of symbols

11 outer ring 12 cam surface 13 pocket 14 roller 15 retaining spring 16, 16 'retaining portion 17 shaft 18 spring receiving portion 19 tube portion 20 transfer dummy 21, 21' shaft hole 22 collar 23 mating part

Claims (4)

  A pocket (13) including a cam surface (12) inclined in the circumferential direction is formed on the inner surface of the outer ring (11), and a roller (14) and a pressing spring (15) of the roller (14) are formed in the pocket (13). The roller (14) and the retaining spring (15) are prevented from coming off in the axial direction (16), (16 ') at both ends of the outer ring (11), and the cam surface ( 12) and a shaft (17) inserted through the outer ring (11) form a wedge angle θ that narrows in a certain direction, and the pressing spring (15) causes the roller (14) to narrow in the wedge angle θ. In the one-way clutch biased by the outer ring (11), the outer ring (11) is formed to have an elliptical shape in its axial cross section, and the cam surface ( 12) The one-way clutch characterized by being formed.   The elliptical outer ring (11) has a shell shape, and the retaining portions (16), (16 ′) are formed in a collar shape by bending both ends of the outer ring (11) inward. The one-way clutch according to claim 1.   The spring receiving part (18) which receives the one end part of the said holding | suppressing spring (15) is formed in the edge part which becomes the expansion side of the wedge angle (theta) of the said pocket (13), The Claim 1 or 2 characterized by the above-mentioned. One-way clutch as described.   A transfer dummy (20) having a cylindrical portion (19) having the same diameter as that of the shaft (17) is inserted into the outer ring (11), whereby the inner diameter direction of the rollers (14) and the holding spring (15). The one-way clutch according to any one of claims 1 to 3, characterized in that it is prevented from slipping off.

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