JP2008128329A - Torque limiter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly change and adjust a generated torque value in a roller type torque limiter. <P>SOLUTION: An energizing means 24 energizing a roller 23 enclosed in a pocket of an outer ring 22, in a narrowing direction of the pocket is composed of a cage 35 and a coil spring 36. Both ends of the coil spring 36 are engaged with the cage 35 and a cover 25 respectively, and the cover 25 is rotated by a suitable angle to change the diameter of the coil spring 36 and to adjust energizing force applied to the roller 23 through a columnar part 38 of the cage 35. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a torque limiter used in a paper feeding unit or the like of an office machine, and particularly aims at cost reduction and compactness.

  As a conventionally known torque limiter, there is a roller type that uses a torque when a roller stored in a pocket of an exterior body is urged toward the wedge portion and the shaft rotates in the expanding direction of the wedge portion. (See Patent Document 1).

  As shown in FIG. 8, the details are as follows. The outer body 1, the outer ring 2 fitted to the inner surface of the outer body 1, the rollers 4 housed in the pocket 3 formed on the inner surface of the outer ring 2, The roller 4 includes a spring piece 5 as an urging means, a retainer 6, an inner ring 7 that is rotatably fitted to the center of the outer ring 2, and a lid that closes the open end of the exterior body 1. The pocket 3 is composed of a cam surface 9 formed at a predetermined interval in the circumferential direction on the inner diameter surface of the outer ring 2 and a cage 6 accommodated in the inner diameter surface of the outer ring 2 at six locations in the circumferential direction in the figure. It is formed. A wedge angle θ is formed by the cam surface 9 and the outer diameter surface of the inner ring 7, and the roller 4 is urged by the spring piece 5 in a narrow direction of the wedge angle θ.

  In the torque limiter described above, when the shaft 11 penetrating the inner ring 7 is rotated in the direction indicated by the arrow A, that is, in the direction in which the wedge angle θ is enlarged, the inner ring 7 is relative to the exterior body 1 integrally with the shaft 11. By rotating, it idles while generating a certain torque. When the shaft 11 rotates in the direction opposite to the above, the roller 4 moves in the narrow direction of the wedge angle θ to cause the biting, and the shaft 11 is locked with respect to the exterior body 1.

In addition to the roller-type torque limiter as described above, a small diameter portion of a coil spring having a two-stage outer diameter is fastened to a shaft inserted through the exterior body, and both ends of the coil spring are engaged with the exterior body. A coil spring type using a torque generated when the shaft relatively rotates in the direction in which the small diameter portion expands is also known (Patent Document 2). Also in this case, when the shaft rotates in the opposite direction to the exterior body, the small-diameter portion is bound to the shaft and locks the shaft relative to the exterior body.
Japanese Patent Publication No.8-14292 Japanese Patent Publication No. 6-48014

  In the roller type torque limiter, the spring piece 5 is provided for each roller 4 of each pocket 3. Therefore, when the torque value needs to be changed or adjusted, all the spring pieces 5 are replaced. There is a problem that is necessary and very time-consuming.

  In addition, in the coil spring type torque limiter, since the diameter of each winding of the coil spring is reduced at the time of locking, the coil spring is locked before being locked. Therefore, the coil spring type torque limiter is delayed in time compared to the roller type torque limiter. There is a problem of lack of responsiveness.

  Accordingly, an object of the present invention is to use a roller type torque limiter with excellent responsiveness, and to easily change and adjust the urging force.

  In order to solve the above-described problems, a torque limiter according to the present invention is accommodated in an exterior body 21, an outer ring 22 fitted to an inner diameter surface of the outer body 21, and a pocket 39 formed on the inner diameter surface of the outer ring 22. A roller 23, a biasing means 24 for the roller 23 and a lid 25 for closing the open end of the outer casing 21, and a cam surface 33 formed on the bottom surface of the pocket 39 and a central portion of the outer ring 22 in use. A wedge angle θ is formed between the inserted shaft 41 and the biasing means 24 applies a required biasing force in the narrow direction of the wedge angle θ to the roller 23 by a so-called coil spring type torque. A limiter is assumed.

  In the torque limiter as described above, in the present invention, each pocket 39 is constituted by a cage 35 and a cam surface 33 that are rotatably fitted to the inner diameter surface of the outer ring 22, and the urging means 24 is The coil spring 36 is interposed between the cage 35 and the lid 25. Both ends of the coil spring 36 are engaged with the cage 35 and the lid 25, respectively, and the lid 25 is rotated at an appropriate angle. Then, by twisting the coil spring 36 in the direction of diameter reduction, the cage 35 is rotated in the twisting direction to generate the biasing force, and the biasing force is adjusted by adjusting the rotation of the lid 25. Configured.

  In the torque limiter having the above-described configuration, when the generated torque value is changed / adjusted, when the cover 25 is adjusted and rotated in the torsion direction of the coil spring 36, the roller 23 is relatively large via the column portions 38 of the cage 35. Can exert a biasing force. Further, if the adjustment rotation is performed in the opposite direction to the above, it can be changed to a relatively small urging force.

  In addition to the configuration of the torque limiter, a configuration in which an inner ring 49 is provided may be employed.

  As described above, according to the present invention, the urging force for all the rollers 23 can be adjusted at the same time by an equal amount by the adjustment rotation of the lid 25, so that the adjustment work of the generated torque can be performed easily and quickly. There is. Further, by adding the inner ring 49, the torque can be adjusted after being removed from the shaft 41, and can be attached to the shaft 41, the adjustment work can be facilitated, and the generated torque value can be reduced. A highly accurate torque value can be obtained without being affected by tolerances.

  Embodiments of a torque limiter according to the present invention will be described below with reference to FIGS. 1 to 7 of the accompanying drawings.

  The torque limiter according to the first embodiment shown in FIGS. 1 to 3 includes an outer body 21, an outer ring 22 fitted to the inner surface of the outer body 21, and a roller housed in a pocket formed on the inner surface of the outer ring 22. 23, an urging means 24 for the roller 23 and a lid 25 for closing the open end of the exterior body 21.

  As shown in FIGS. 1 and 3, the exterior body 21 is a cylindrical body with one end closed and the other end opened, and a shaft hole 26 is formed on the closed end side. Engagement protrusions 27 are provided on the outer surface of the closed end surface at positions symmetrical to the center of the shaft hole 26. Further, a step portion 28 is formed in the middle of the inner diameter surface, and an axial detent rib 29 (see FIG. 2A) is provided in the circumferential direction from the step portion 28 to the inner diameter surface on the small diameter side on the closed end side. The required number is formed. A circumferential groove 31 is formed at the open end on the large diameter side. In addition to the cylindrical body shown in the figure, the exterior body 21 has forms such as a case where the outer peripheral surface is a gear and a case where it is a pulley.

  The outer ring 22 is press-fitted and fixed to the inner diameter surface of the outer diameter side of the outer casing 21. The outer ring 22 is provided with an anti-rotation recess 32 (see FIGS. 2A and 3) that fits the anti-rotation rib 29 described above. In addition, cam surfaces 33 are provided on the inner diameter surface at regular intervals in the circumferential direction. Each cam surface 33 is formed in a groove shape extending over the entire length in the axial direction, and includes a surface inclined in a certain direction. Further, a guide surface 34 (see FIG. 1) is formed on the inner diameter surface of the outer diameter side end portion of the outer ring 22.

  The urging means 24 includes a cage 35 and a coil spring 36. The cage 35 is composed of an annular ring portion 37 and column portions 38 that are spaced apart in the circumferential direction on one side and are provided in the axial direction. The outer diameter of the ring portion 37 is formed to be the same size as the outer diameter of the outer ring 22, and a step portion is provided in the column portion 38 of the ring portion 37. The retainer 35 has a pillar portion 38 fitted into the inner diameter surface of the outer ring 22, and a stepped portion of the ring portion 37 is fitted to the guide surface 34 of the outer ring 22, and is applied to the end surface of the outer ring 22. The retainer 35 has its ring portion 37 guided by the guide surface 34, the column portion 38 is guided by the inner diameter surface of the outer ring 22, and is further axially regulated by the end surface of the outer ring 22. It can be rotated.

  Each column portion 38 is inserted between the cam surface 33 and the cam surface 33 of the outer ring 22, and a pocket 39 is formed by the cam surface 33 and the opposing surfaces of the column portions 38 on both sides thereof. Is stored. As shown in FIG. 2A, in a state where the roller 23 is caught in the wedge portion formed by the cam surface 33 and the outer diameter surface of the shaft 41 inserted in use, the cam surface 33 and the shaft The angle formed by 41 tangent lines is called the wedge angle θ. A small hole 40 is provided on the outer end surface of the ring portion 37.

  2A and 2B, when the retainer 35 rotates in the narrow direction of the wedge angle θ, the column portion 38 moves the roller 23 in the narrow direction of the wedge angle θ and locks it. Let Further, when the retainer 35 rotates in the opposite direction, the roller 23 is moved in the direction in which the wedge angle θ is enlarged to release the lock.

  The coil spring 36 has hooks 42 and 43 bent outward in the axial direction at both ends thereof, and is interposed between the ring portion 37 of the retainer 35 and the lid 25.

  A shaft hole 44 is formed in the lid 25, and a cylindrical portion 45 is provided around the shaft hole 44 on the inner surface thereof. A retaining rib 46 is provided on the outer diameter surface of the lid 25. A small hole 47 for receiving the hook 43 is provided on the inner surface of the lid 25. In addition, on the outer surface of the lid 25, locking holes 48 for adjusting tools are provided at four locations in the circumferential direction.

  The lid 25 has a retaining rib 46 fitted into the circumferential groove 31 at the open end of the exterior body 21, and the tip of the cylindrical portion 45 is abutted against the ring portion 37 of the cage 35. The lid 25 can be rotated by using an adjustment tool when changing or adjusting the generated torque, but is tightly fitted to the extent that it is not rotated by the torsional force of the coil spring 36.

  A ring portion 37 provided on the inner surface of the lid 25 by the fitting of the lid 25 is sandwiched between the outer ring 22 and the cylindrical portion 45, whereby the axial position of the cage 35 is determined. The coil spring 36 is fitted around the outer diameter surface of the cylindrical portion 45 with a radial gap, and the hooks 42 and 43 are inserted into the small holes 40 and 47, respectively.

  The torque limiter of the first embodiment is as described above, and is fitted to the shaft 41 for use. The urging force is applied to each roller 23 by inserting and locking the adjusting tool into the locking hole 48 of the lid 25, which is opposite to the winding direction of the coil spring 36 (left-handed in the figure) (as viewed from the lid 25 side). And the coil spring 36 is reduced in diameter. As a result, the other hook 42 is pulled in the winding direction, so that the retainer 35 rotates in that direction (the direction of the arrow A in FIGS. 2A and 2B), and each column portion 38 moves relative to each roller 23. The biasing force is exerted in the narrow direction of the wedge angle θ. When changing / adjusting the urging force, the adjustment tool is locked in the locking hole 48 of the lid 25 as described above, and the diameter of the coil spring 36 is changed by rotating the adjustment tool in either the left or right direction. As a result, all the rollers 23 can be changed and adjusted at the same time and in equal amounts.

  As described above, the shaft 41 rotates relative to the exterior body 21 in the direction opposite to the wedge angle θ (see the arrow B in FIG. 2A) with a predetermined urging force applied to the rollers 23. In this case, the roller 23 moves in the direction in which the wedge angle θ is enlarged, and the shaft 41 rotates idly while generating a predetermined torque. When rotating in the reverse direction, the roller 23 moves in the narrow direction of the wedge angle θ and quickly locks.

  The torque limiter according to the second embodiment shown in FIGS. 4A and 4B is obtained by adding an inner ring 49 to the inner diameter side of the cage 35 in addition to the configuration of the first embodiment. One end portion of the inner ring 49 is supported by a bearing portion 50 provided on the inner diameter surface of the shaft hole 26 of the exterior body 21, and the outer diameter surface of the other end portion is supported by the shaft hole 44 of the lid 25. The shaft 41 is inserted into the inner diameter surface of the inner ring 49, and the pin 51 standing on the shaft 41 is engaged with the recess 52 of the inner ring 49.

  Since the other configurations and operations of the torque limiter of the second embodiment are substantially the same as those of the first embodiment, description thereof will be omitted.

  As in the second embodiment, when the inner ring 49 is present, torque can be set, changed, or adjusted even when the inner ring 49 is removed from the shaft 41, and the generated torque value is a tolerance of the outer diameter surface of the shaft 41. Thus, the torque generated on the outer diameter surface of the inner ring 49 which is well managed can be used, and a stable and highly accurate torque can be obtained.

  The third embodiment shown in FIGS. 5 to 7 has a configuration in which the cam surface 33 is provided on the outer diameter surface of the inner ring 49 in the configuration of the second embodiment. Since the other configurations and operations of the torque limiter of the third embodiment are substantially the same as those of the first and second embodiments, description thereof will be omitted.

These are longitudinal side views of the torque limiter of the first embodiment. (A) The figure is sectional drawing of the X1-X1 line | wire of FIG. 1, (b) A figure is a partial expanded sectional view of (a) figure. FIG. 3 is an exploded perspective view of the first embodiment, showing a part in cross section. (A) The figure is a longitudinal side view of Example 2, (b) The figure is a sectional view taken along line X2-X2 of (a). Vertical side view of Example 3 (A) The figure is a sectional view taken along line X3-X3 in FIG. The perspective view of the inner ring of Example 3 Cross section of conventional example

Explanation of symbols

21 Outer body 22 Outer ring 23 Roller 24 Energizing means 25 Lid 26 Shaft hole 27 Engagement projection 28 Stepped portion 29 Rotation prevention rib 31 Circumferential groove 32 Rotation prevention concave portion 33 Cam surface 34 Guide surface 35 Cage 36 Coil spring 37 Ring portion 38 Pillar portion 39 Pocket 40 Small hole 41 Shaft 42 Hook 43 Hook 44 Shaft hole 45 Cylindrical portion 46 Retaining rib 47 Small hole 48 Locking hole 49 Inner ring 50 Bearing portion 51 Pin 52 Recess

Claims (5)

  An outer body (21), an outer ring (22) fitted to an inner surface of the outer body (21), a roller (23) housed in a pocket (39) formed on the inner surface of the outer ring (22), A cam surface (33) formed on the bottom surface of the pocket (39), comprising a biasing means (24) for the roller (23) and a lid (25) for closing the open end of the exterior body (21) A wedge angle θ is formed between the outer ring (22) and the shaft (41) inserted through the central portion of the outer ring (22), and the biasing means (24) is required in the narrow direction of the wedge angle θ with respect to the roller (23). In the torque limiter configured to exert an urging force, the pocket (39) is constituted by a cage (35) and a cam surface (33), which are rotatably fitted to an inner diameter surface of the outer ring (22). The biasing means (24) is constituted by a coil spring (36) interposed between the retainer (35) and the lid (25). Both ends of the spring (36) are engaged with the cage (35) and the lid (25), respectively, and the lid (25) is rotated by an appropriate angle to twist the coil spring (36) in the diameter-reducing direction. The torque limiter is characterized in that the retainer (35) is rotated in the twisting direction to generate the biasing force, and the biasing force is adjusted by adjusting the rotation of the lid (25). .   A cylindrical portion (45) is formed on the inner surface of the lid (25), and the cylindrical portion (45) is pressed against the retainer (35) to determine the axial position of the retainer (35). The torque limiter according to claim 1.   An outer body (21), an outer ring (22) fitted to the inner surface of the outer body (21), rollers (23) housed in a pocket (39) formed on the inner surface of the outer ring (22), A biasing means (24) for the roller (23), an inner ring (49) rotatably inserted in a central portion of the outer ring (22), and a lid (25) for closing the open end of the exterior body (21); A wedge angle θ is formed between the cam surface (33) formed on the bottom surface of the pocket (39) and the inner ring (49), and the roller (23) is moved by the biasing means (24). In the torque limiter configured to exert a required urging force in the narrow direction of the wedge angle θ, the cage (35) is rotatable between the inner diameter surface of the outer ring (22) and the outer diameter surface of the inner ring (49). The pocket (39) is constituted by the column portion (38) of the retainer (35) and the cam surface (33), and the biasing means (24) is connected to the retainer (24). 35) and a coil spring (36) interposed between the lid (25), and both ends of the coil spring (36) are engaged with the cage (35) and the lid (25), respectively. By rotating the lid (25) at an appropriate angle and twisting the coil spring (36) in the direction of diameter reduction, the retainer (35) is rotated to generate the biasing force, and the lid (25) The torque limiter is characterized in that the biasing force is adjusted by adjusting the rotation of the torque limiter.   The torque limiter according to claim 3, wherein the cam surface (33) is formed on either the inner diameter surface of the outer ring (22) or the outer diameter surface of the inner ring (49).   A cylindrical portion (45) is formed on the inner surface of the lid (25), and the axial position of the retainer (35) is determined by pressing the cylindrical portion (45) against the retainer (35). The torque limiter according to claim 3 or 4, wherein

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