JP4549098B2 - Spring clutch - Google Patents

Description

  The present invention relates to a spring clutch, and more particularly to a one-way spring clutch having a limiter function.

  A torque input member and an output member are fitted in a concentric state with a coil spring interposed therebetween, one end of the coil spring is fixed to the input member or the output member, and the other end is a free end. Conventionally, there is a spring clutch in which the input member is locked to the output member by the diameter expansion or contraction action caused by the rotation of the coil spring accompanying the rotation in a certain direction, and the input member is idled by the rotation in the opposite direction. (Patent Document 1).

  In the section of the “Embodiment of the Invention” of Patent Document 1, the first embodiment (FIGS. 1 to 5 of Patent Document 1) is a two-way spring clutch. In the state where the control arm is fixed at a fixed position, a one-way spring clutch is formed. In this case, the hook at one end of the coil spring is fixed to the output member, and the hook at the other end is a free end. The hook is in contact with the control arm (see FIGS. 4A and 5A of Patent Document 1).

In the spring clutch having the above structure, when the input member rotates in a certain direction, the input member locks against the output member by the diameter reducing action of the coil spring, and torque is transmitted (FIG. 4 (a), FIG. 5 (a). )), The input member idles due to the diameter expansion action of the coil spring during rotation in the reverse direction, and the transmission of torque is interrupted.
JP 2000-269490 A (first embodiment, FIGS. 1 to 5)

  As described above, in a structure in which the hook on the free end side of the coil spring is in contact with the control arm and there is no gap in the lock direction (reducing diameter direction) when there is no load, it exists between the coil spring and the input member. By deforming only a slight gap, a locking and idling clutch action corresponding to the rotation direction is performed. For this reason, when a high load torque is applied in the locking direction, there is little deformation margin of the coil spring, and if the diameter reducing action becomes stronger than a certain level, the hook on the free end side is strongly pressed against the control arm, which may cause damage. is there.

  SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a coil spring with a required deformation margin and to eliminate the possibility of breakage of the hook on the free end side when a high load torque is applied.

  In order to solve the above-described problems, the present invention is configured such that an outer ring and an inner ring are fitted in a coaxial state, a coil spring is interposed between the inner ring surface of the outer ring and the outer ring surface of the inner ring, and the coil spring is connected to the inner ring surface of the outer ring. And one end of the coil spring is a free end and the other end is fixed to the inner ring, and viewed from the free end of the coil spring. When the outer ring rotates in the winding direction, the outer ring is locked to the inner ring by the diameter expanding action of the coil spring, and when the outer ring rotates in the opposite direction, the outer ring is idled by the diameter reducing action of the coil spring. The spring clutch employs a configuration in which a diameter expansion limiting means is provided on the free end side of the coil spring, thereby providing a limiter function for idling the outer ring at the time of high load torque.

  The diameter expansion limiting means is formed by inserting a circumferential restriction groove provided in the inner ring and a hook provided at the free end of the coil spring into the restriction groove, as viewed from the free end side of the coil spring. The inner end wall of the restriction groove on the winding direction side of the coil spring is defined as a restriction end wall, and a constant interval is provided between the hook and the restriction end wall when no load is applied.

  In the above configuration, the outer ring is the input member, and the shaft fitted into the inner ring or the inner ring inner surface serves as the output member, and transmits torque to the output side according to the rotation direction of the outer ring that is the input member, and vice versa. It functions as a one-way clutch in which torque transmission is cut off during rotation.

  On the contrary, when the outer ring is an output member and the shaft is used as an input member, the configuration is as follows. That is, the outer ring and the inner ring, the inner ring and the shaft are fitted in a coaxial state, a coil spring is interposed between the inner ring inner surface and the shaft outer surface, and the coil spring is brought into contact with the shaft outer surface and the inner ring. A clearance is provided between the coil spring and one end of the coil spring as a free end, and the other end is fixed to the inner ring. When viewed from the free end of the coil spring, the direction opposite to the winding direction is provided. When the shaft rotates, the shaft is locked to the inner ring by the diameter reducing action of the coil spring, and when the shaft rotates in the opposite direction, the shaft is idled by the diameter expanding action of the coil spring. In the spring clutch, a configuration is adopted in which a diameter reduction limiting means is provided on the free end side of the coil spring, thereby providing a limiter function for idling the shaft during high load torque.

  The diameter reduction limiting means is formed by inserting a circumferential restriction groove provided in the inner ring and a hook provided at a free end of the coil spring into the restriction groove, and the free end side of the coil spring. An inner end wall of the restriction groove opposite to the winding direction of the coil spring is defined as a restriction end wall, and a constant interval is provided between the hook and the restriction end wall when no load is applied. .

  By providing the above-mentioned diameter expansion restriction means or diameter reduction restriction means, the deformation allowance of the coil spring is increased, it is possible to cope with a wide range of load torque fluctuations, and the limiter function works for a high load torque above a certain level. Therefore, the risk of breakage of the hook can be eliminated.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the spring clutch of the first embodiment is a one-way spring clutch, and an outer ring 1 serving as an input member, and a hollow shaft 3 is concentrically connected to an inner diameter side of the outer ring 1 via a rolling bearing 2. The inner ring 4 is fitted and integrated with the outer diameter surface of the shaft 3. A spacer 5 is interposed between the inner end surface of the inner ring 4 and the rolling bearing 2. A coil spring 6 is interposed in the gap between the inner diameter surface of the outer ring 1 and the outer diameter surface of the inner ring 4.

  The inner ring 4 is provided with a flange portion 8 on the outer end portion of the body portion 7 facing the inner diameter surface of the coil spring 6 and a flange portion 8 'on the inner end portion (see FIG. 5). A restriction groove 9 having a length direction in the circumferential direction is provided on the outer surface of the body portion 7 at a position close to the flange portion 8 of the outer end portion. When the restriction groove 9 is viewed from the end of the inner ring 4 at the outer end (the flange 8 side) (see FIG. 2), the right end wall is referred to as a restriction end wall 11, and the other left end wall is the free end. This is called wall 12.

  Further, a circumferential notch 13 is formed on the outer peripheral surface of the flange portion 8 'at the inner end (see FIGS. 6 and 7). When the notch 13 is viewed from the inner end (the collar 8 ′ side) of the inner ring 4, the notch 13 gradually becomes deeper from the right end 13a to the left end 13b, and near the left end 13b, It becomes the same height as the diameter. An arcuate locking groove 14 that is cut into the collar portion 8 ′ from the left end 13 b and opened on the end face of the inner ring 4 is formed. The locking groove 14 bends gently so as to gradually approach the inner diameter surface of the inner ring 4, and a bent groove 15 that is bent outwardly at the end is provided.

As shown in FIG. 5 and FIG. 6, the coil spring 6 is a right-handed steel wire having a square cross section, and an inward hook 17 is provided at the outer end of the straight portion 16 formed to have the same diameter over the entire length. The outward hook 18 is provided at the inner end. The straight portion 16 has an outer diameter that is substantially equal to the inner diameter of the outer ring 1 and is slightly larger than the outer diameter of each collar portion 8, 8 ′. The hooks 17 and 18 are provided corresponding to the positions of the restriction groove 9 and the bending groove 15, respectively. The coil spring 6 is fitted to the body portion 7 of the inner ring 4 with a required tightening margin while forcibly expanding the end portions of the hooks 17 and 18 in opposition to the elastic force, and includes an outward hook 18. A portion having a required length is pulled out from the body portion 7 of the inner ring 4 to the notch 13 and is forcibly fitted into the locking groove 14 from the inner end face side of the inner ring 4. At the same time, the outward hook 18 is fitted into the bending groove 15. As a result, the outward hook 18 of the coil spring 6 is fitted and fixed to the bending groove 15 without rattling.

  Further, the inward hook 17 is fitted into the restriction groove 9 so that there is room in both the length direction and the width direction. In the longitudinal direction, as shown in FIG. 4A, there is a certain gap a between the hook 17 and the regulating end wall 11, and between the free end wall 12 on the opposite side. There is also a certain gap b. The gap b may be set to a size close to zero, but the gap a is set as large as possible. In the illustrated case, the gaps a and b are set to the same size.

  In actual assembly, after the coil spring 6 is fitted to the inner ring 4 as described above, the rolling bearing 2 is fitted and integrated with the shaft 3 together with the inner ring 4, and then the outer ring 1 and the coil spring 6 are integrated. It fits on the outer diameter side of the rolling bearing 2. As a result, the coil spring 6 is assembled in a state of lightly contacting the inner diameter surface of the outer ring 1 (see FIG. 1). This assembled state is an unloaded state. At this time, a certain tightening margin exists between the coil spring 6 and the inner surface of the outer ring 1.

  The spring clutch of the first embodiment is configured as described above, and the operation thereof will be described next. From the no-load state, the outer ring 1 as an input member is seen in the winding direction (right direction) of the coil spring 6 (see arrow A in FIG. 2) when viewed from the collar 8 side (outer end side of the inner ring 4). When rotated, the coil spring 6 abutting on the inner diameter surface of the outer ring 1 is rotated, and a diameter expansion effect is caused by the presence of a tightening margin existing between the inner diameter surface of the outer ring 1 and the coil spring 6. As a result, the pressing force of the coil spring 6 against the inner surface of the outer ring 1 becomes stronger, the outer ring 1 is integrated with the coil spring 6, and the inner ring 4 is locked. As a result, torque is transmitted to the shaft 3. At this time, the inward hook 17 moves to the regulating end wall 11 side according to the diameter expansion amount of the coil spring 6. When the load torque acting on the shaft 3 becomes larger than a certain value, the inward hook 17 engages with the regulating end wall 11, so that further diameter expansion action is prevented. When the load torque increases further, slip occurs on the inner diameter surface of the coil spring 6 and the outer ring 1, and the outer ring 1 rotates idle. That is, when a load torque larger than a certain level is applied, the limiter function is activated, and an excessive load is prevented from acting on the inward hook 17. FIG. 4B qualitatively shows that when the load torque becomes larger than a certain value during rotation in the locking direction, the limiter function acts and the transmission torque becomes constant.

  Further, when the outer ring 1 rotates counterclockwise from the unloaded state (see arrow B in FIG. 2), the coil spring 6 has a diameter reducing action, and the outer ring 1 idles with respect to the inner ring 4 (see FIG. 4B). ). At this time, the inward hook 17 moves toward the free end wall 12 according to the amount of diameter reduction, or is absorbed by the straight portion 16 and the amount of movement becomes substantially zero.

  In the first embodiment, the outer ring 1 is the input side, the inner ring 4 and the shaft 3 side is the output side, the outer diameter surface of the coil spring 6 is brought into contact with the inner diameter surface of the outer ring 1, and the outer ring 1 is rotated according to the rotation direction of the outer ring 1. Torque is transmitted to the shaft 3 side, and the transmission is cut off.

  On the other hand, the torque limiter of the second embodiment shown in FIGS. 8 to 11 is used so that the shaft 3 is on the input side and the outer ring 1 is on the output side, and the outer ring 1, the inner ring 4, and the inner ring 4 are used. And the shaft 3 are fitted in a coaxial state. A rolling bearing 2 is interposed between the shaft 3 and the outer ring 1.

  A coil spring 6 is interposed in a gap between the inner diameter surface of the inner ring 4 and the outer diameter surface of the shaft 3, and the coil spring 6 is brought into contact with the outer diameter surface of the shaft 3 with a required tightening margin and the inner diameter surface of the inner ring 4. There is a gap between them. An outward hook 22 is formed at the outer end of the coil spring 6, and an inward hook 23 (see FIG. 10) is formed at the inner end.

  The inner ring 4 is provided with inwardly extending flange portions 21, 21 ′ at both inner and outer end portions of the inner diameter surface. The inner ring portion 21 ′ is continuous from the inner diameter surface 24 of the inner ring 4 and is opened to the inner end surface of the inner ring 4. A stop groove 25 is provided (see FIG. 11). The locking groove 25 gradually curves so as to approach the outer diameter surface of the inner ring 4, and an inwardly bent portion 26 is formed at the tip portion.

  Further, a restriction groove 27 having a length direction in the circumferential direction is provided on the inner diameter surface of the inner ring 4 near the outer collar portion 21. The left end wall when the restriction groove 27 is viewed from the end of the outer collar portion 21 of the inner ring 4 is referred to as a restriction wall 28 (see FIG. 9), and the other end wall is referred to as a free end wall 29.

  The coil spring 6 is attached to the outer diameter surface of the shaft 3 with a required tightening allowance, and a portion having a required length including the inward hook 23 is pulled out from the inner diameter surface of the inner ring 4 from the inner collar portion 21 ′. The engaging groove 25 and the bent portion 26 are fitted. Accordingly, the inward hook 23 of the coil spring 6 is fitted and fixed to the bent portion 26 without rattling.

  Further, the outward hook 22 is fitted into the restriction groove 27 so that there is room in both the length direction and the width direction. In the longitudinal direction, as shown in FIG. 9, there is a certain gap a between the hook 22 and the regulating end wall 28, and also between the opposite free end wall 29. There is a gap b. The gap b may be set to a size close to zero, but the gap a is set as large as possible. In the illustrated case, the gaps a and b are set to the same size.

  The spring clutch of the second embodiment is configured as described above, and the following operation will be described. When the shaft 3 as the input member rotates in the direction opposite to the winding direction of the coil spring 6 (left direction) (see arrow B in FIG. 9) when viewed from the collar portion 21 side (outer end portion side of the inner ring 4), The coil spring 6 in contact with the outer diameter surface of the shaft 3 is rotated, and the diameter reducing action is caused by the presence of a tightening margin existing between the outer diameter surface of the shaft 3 and the coil spring 6. As a result, the pressing force of the coil spring 6 against the outer diameter surface of the shaft 3 becomes strong, the shaft 3 is integrated with the coil spring 6, and the inner ring 4 is locked. As a result, torque is transmitted to the outer ring 1.

  At this time, the outward hook 22 moves to the regulating end wall 28 side according to the diameter reduction amount of the coil spring 6. When the load torque acting on the outer ring 1 becomes larger than a certain level, the outward hook 22 engages with the regulating end wall 28, so that further diameter reducing action is prevented. When the load torque further increases, slippage occurs on the outer diameter surfaces of the coil spring 6 and the shaft 3, and the shaft 3 rotates idle. That is, when a load torque larger than a certain level is applied, the limiter function is activated, and an excessive load is prevented from acting on the outward hook 22.

  Further, when the shaft 3 rotates clockwise (see arrow A in FIG. 9) from the above-mentioned no-load state, the coil spring 6 has a diameter expanding action, and the shaft 3 rotates idly with respect to the inner ring 4. At this time, the outward hook 22 moves toward the free end wall 29 according to the amount of diameter expansion, or is absorbed by the straight portion 16 of the coil spring 6 and the amount of movement becomes substantially zero.

Sectional drawing of Embodiment 1 Sectional view taken along line II-II in FIG. Sectional view taken along line III-III in FIG. (A) Partially enlarged sectional view of FIG. 2, (b) Torque characteristic diagram Exploded perspective view Partially exploded perspective view of the above End view of the combined state of FIG. Sectional drawing of Embodiment 2 Sectional view of IX-IX line Cross-sectional view of XX line Perspective view of the inner ring

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Rolling bearing 3 Shaft 4 Inner ring 5 Spacer 6 Coil spring 7 Body part 8, 8 'collar part 9 Restriction groove 11 Restriction end wall 12 Free end wall 13 Notch 14 Locking groove 15 Bending groove 16 Straight part 17 Inward Hook 18 Outward hook 21, 21 ′ Brim portion 22 Outward hook 23 Inward hook 24 Inner surface 25 Locking groove 26 Bending portion 27 Restriction groove 28 Restriction end wall 29 Free end wall

Claims (2)

The outer ring and inner ring are fitted coaxially, and a coil spring is interposed between the inner ring outer surface and the inner ring outer diameter surface so that the coil spring contacts the outer ring inner surface and a gap between the inner ring outer diameter surface and the inner ring. And one end of the coil spring as a free end and the other end fixed to the inner ring, and when the outer ring rotates in the winding direction when viewed from the free end of the coil spring, the coil spring In a spring clutch in which the outer ring is locked to the inner ring by the diameter expanding action and the outer ring is idled by the diameter reducing action of the coil spring when the outer ring rotates in the opposite direction, the spring is expanded to the free end side of the coil spring. diameter provided limiting means, thereby by idle the outer ring during the locking direction of the high load torque imparted a limiter function to prevent damage of the coil spring, the diameter expansion limitation means, and circumferential direction of the provided in the inner ring Regulation groove The hook is provided at the free end of the coil spring in the restricting groove, and the inner end wall of the restricting groove on the winding direction side of the restrictive groove viewed from the free end side of the coil spring is defined as the restricting end. wall defines the opposite side of the inner end wall of the free end wall, the digits are set a fixed distance between and between the hook and the free end wall of the hook and the regulating end wall at the time of no load Spring clutch featured. The outer ring and the inner ring, the inner ring and the shaft are fitted coaxially, a coil spring is interposed between the inner ring inner diameter surface and the shaft outer diameter surface, and the coil spring is brought into contact with the shaft outer diameter surface and the inner ring inner diameter surface. A first end of the coil spring is used as a free end and the other end is fixed to an inner ring, and the shaft is arranged in a direction opposite to the winding direction when viewed from the free end of the coil spring. A spring clutch that locks the shaft to the inner ring by the diameter reducing action of the coil spring when the coil rotates, and causes the shaft to idle by the diameter expanding action of the coil spring when the shaft rotates in the opposite direction. in the diameter-reduction limiting means on the free end side of the coil spring is provided, thereby by idle the axis during the locking direction of the high load torque imparted a limiter function to prevent damage of the coil spring, the diameter Limit means A circumferential restriction groove provided in the inner ring and a coil spring of the restriction groove as viewed from the free end side of the coil spring formed by inserting a hook provided at the free end of the coil spring into the restriction groove. The inner end wall on the winding direction side is defined as a free end wall, and the inner end wall on the opposite side is defined as a regulating end wall, and when no load is applied between the hook and the regulating end wall and between the hook and the free end wall. spring clutch, characterized in that digits each set a constant distance between them.

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