JP2007147087A - Torque limiter and rotary member with torque limiter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact torque limiter to be used for a personal printer and the like. <P>SOLUTION: This torque limiter has a sleeve 8 having an annular boss portion 7, and a ring-like elastic member 9. The sleeve 8 generates a radial force relative to a shaft 3 inserted in the sleeve 8 by imparting elasticity in the diameter-reducing direction to the sleeve 8 by fitting the elastic member 9 onto the sleeve 8 to reduce its diameter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a torque limiter used in a drive unit such as a paper feed unit of a small printer such as a personal printer, and a rotating body with a torque limiter.

  As a torque limiter used in a drive unit such as a paper feeding unit of office equipment, a friction type and a magnet type are conventionally known. Conventionally known friction type torque limiters include an internal member, an external member fitted to the internal member so as to be relatively rotatable, and a coil attached to the outer diameter surface of the internal member with a required binding force. A spring, and a lid fitted to the external member between the internal member and the external member. The hook at one end of the coil spring is engaged with the external member, and the hook at the other end is engaged with the lid. By engaging with each other, a constant torque is generated by friction between the internal member and the coil spring (Patent Document 1).

Further, the torque limiter is connected to a rotating body such as a roller on the shaft, and is positioned with respect to the shaft by stopping one end with a pin and the other end with a retaining ring.
Japanese Patent Application Laid-Open No. 11-247881

  With the demand for downsizing of office equipment and the like, the conventional torque limiter described above is composed of a combination of parts such as external members and internal members, so there is a certain limit to reducing the outer diameter of the torque limiter. There is. In order to reduce the number of parts, a structure in which a rotating body such as a roller is integrated with an external member of the torque limiter is conceivable, but there is a problem that the manufacturing process becomes complicated and the productivity is lowered.

  When adjusting torque after assembling the torque limiter, the external member is supported by a fixing jig, and the internal member is rotated to adjust the torque while measuring the torque. As described above, the structure is integrated with the rotating body. In such a case, the rotating body must be supported by a fixing jig to adjust the torque. However, since the rotating body has various shapes depending on the application, there is an inconvenience that a fixing jig must be manufactured according to the application, and the setup must be changed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a torque limiter and a rotating body with a torque limiter that do not require torque adjustment while reducing the number of parts to achieve compactness.

(Means 1)
In order to solve the above-described problems, a torque limiter according to the present invention includes a sleeve having an annular boss portion and a ring-shaped elastic body, and imparts elasticity in the diameter-reducing direction to the sleeve. The sleeve is fitted into the sleeve to reduce the diameter, and a radial force is generated on the shaft inserted through the sleeve.

  According to the above configuration, a predetermined torque is generated by the radial force of the sleeve and the frictional force with respect to the shaft of the sleeve. By setting the component dimension of the elastic member to a predetermined value, a predetermined torque value can be obtained without performing torque adjustment after assembly. By using a self-lubricating resin as the material of the sleeve, a case member for preventing the lubricant from scattering and leaking is not necessary.

  The types of self-lubricating resins include polyacetal resin (POM), oil-impregnated plastic, polyamide resin, polyimide resin, high-density polyethylene resin, polybutylene terephthalate resin (PBT), ABS resin, fluororesin (PTFE), and fluororesin A polymer alloy containing polyphenylene sulfide resin (PPS), polycarbonate resin (PC), liquid crystal polymer resin (LCP), or polyphenylene oxide resin (PPO) can be used.

  As the above-mentioned elastic body, a cylindrical spring separated at one place in the circumferential direction by an axial slit can be used. Further, a plurality of the cylindrical springs stacked, a coil spring, and an elastic C-shape A ring or the like can be used.

(Method 2)
In order to solve the above problems, the present invention is configured by attaching a torque limiter to one end of a rotating body, and assembling the spring around a split sleeve divided by a plurality of axial slits. In a rotating body with a torque limiter that generates a required torque between the split sleeve and the shaft, the split sleeve is formed into a shape whose front end is expanded, and this is required by the binding force of the spring. The configuration reduced in diameter was adopted.

  According to said structure, since a slit is shape | molded in the form wider than before, the slit shaping | molding part of a metal mold | die can be taken sufficiently thickly. As a result, the mold is less likely to be lost.

  In addition, the width of the tip of each divided sleeve piece forming the above-mentioned divided sleeve is set to a size that forms an annular portion by abutting each other when the diameter is reduced to the required diameter by the binding force of the coil spring. Further, it is possible to adopt a configuration in which the width of the portion other than the tip portion of the divided sleeve piece is set to a smaller width. According to this configuration, when the divided sleeve is reduced in diameter by the binding force of the spring, the inner diameter of the opening at the tip is limited to the inner diameter of the annular portion formed by the divided sleeve pieces. For this reason, the relationship between the inner diameter of the ring portion and the outer diameter of the shaft can be designed so that a predetermined torque can be obtained and insertion is easy.

  In addition, a configuration in which a required number of bearing protrusions are arranged in the circumferential direction at both ends of the inner diameter surface of the rotating body to form a radial bearing, and the phase of the position of the bearing protrusions forming each radial bearing is shifted. Can be adopted. According to this configuration, even if there are bearing convex portions at both ends of the inner surface of the rotating body, it is possible to perform die cutting in the axial direction, and it is possible to mold.

  It is possible to employ a configuration in which a coil spring is used as the spring, the number of turns of the coil spring is set to less than a half turn, and hooks at both ends are bent in the outer diameter direction. According to such a winding mode, since there is a superior arc and an inferior arc between the hooks at both ends, the diameter of the coil spring increases when both hooks are pulled toward the inferior arc side relatively. For this reason, the shaft can be easily inserted. In this case, the fraction of the number of turns, that is, the angle of the inferior arc is preferably about 20 to 45 degrees. Further, when a configuration is adopted in which the engaging portion of the both hooks is provided on the end surface on the torque limiter side of the rotating body, and one of the engaging portions is provided with flexibility in the circumferential direction, the flexible engagement is achieved. The diameter of the coil spring can be easily increased by bending the portion toward the inferior arc.

  Note that a spring-like C-shaped ring can also be used as the spring. The binding force can be adjusted by changing the number.

(Method 3)
In order to solve the above-described problems, the present invention is configured by attaching a torque limiter to one end of a rotating body, and assembling the spring around a divided sleeve divided by a plurality of axial slits. In a rotating body with a torque limiter configured to generate a required torque between the divided sleeve and the shaft, the divided sleeve is formed by at least two divided sleeve pieces, and the circumferential length of each sleeve piece with respect to the axial length thereof. A configuration in which the ratio of the lengths in the direction is 0.9 ± 0.1 (0.8 to 1.0) was adopted.

  The configuration in which the spring is assembled at a position offset toward the rotating body side of the split sleeve, the configuration in which a circumferential recess is provided at the spring assembly position of the split sleeve, and the axial length of the split sleeve is The structure formed more than the diameter can be taken.

The torque limiter and the rotating body with the torque limiter according to the present invention exhibit the following effects.
(1) Since the torque is generated by fitting the elastic body to the sleeve having contraction elasticity, the torque value is determined by setting the dimensions of the elastic body to a predetermined value. This eliminates the need to adjust the torque value after assembly, and facilitates the production of a rotating body with a torque limiter. In addition, since an internal member and an external member as in the prior art are unnecessary, the outer diameter of the torque limiter can be reduced.
(2) By providing a positioning portion on the sleeve or the rotating body itself, positioning retaining rings and pins as separate parts are not necessary, and this makes it possible to reduce the size.
(3) When increasing the torque value, it is only necessary to overlap the elastic body in the radial direction, and it is possible to achieve compactness in that it is not affected by the dimension in the axial direction.
(4) By forming the split sleeve portion so that the tip side has an enlarged diameter, the gap between the slits is widened, making it easy to manufacture the mold, preventing the mold from being broken, and its life. Can be maintained for a long time.
(5) Even when a spring having a binding force is attached to the outer diameter surface of the split sleeve, the ring portion at the tip portion restricts the diameter reduction beyond a certain level, so that the shaft can be easily inserted.
(6) Since radial bearings are provided at both ends of the inner diameter surface of the rotating body, the dimensional accuracy of the inner diameter is limited only to this portion, and therefore the manufacture is facilitated. Further, by shifting the phase of the positions of the bearing convex portions on both sides, the undercut portion is eliminated, and the mold can be formed.
(7) When a coil spring is used as a binding means for the split sleeve, the number of turns is set to half or less, preferably about 20 to 45 degrees, so that the hooks at both ends are relatively close to each other. It is possible to easily expand the diameter of the coil spring by moving the coil spring. In particular, by imparting flexibility to the pin-shaped protrusion that locks one hook, the diameter of the coil spring can be increased simply by pushing the protrusion toward the other hook.
(8) When a C-shaped ring is used as a binding means for the split sleeve, the diameter can be easily increased as compared with the coil spring, so that the shaft can be easily inserted. Further, in the case of a coil spring, it is necessary to align the hook mounting positions at both ends of the coil spring with the locking groove, which is inconvenient for the mounting work. Furthermore, the C-shaped ring is compact because it does not require a coil spring equivalent to the hook.
(9) By making the circumferential length of the split sleeve piece relatively large, its rigidity can be increased, and the shape can be stabilized even if the split sleeve rotates relative to the shaft, and stable. Torque can be generated.
(10) By attaching an elastic body such as a C-shaped ring to the base of the split sleeve, it is possible to suppress the generation of moment force in the split sleeve, and the generated torque can be reduced by stabilizing the contact between the shaft and the split sleeve. Stabilize.
(11) By providing a recess for attaching an elastic body such as a C-shaped ring on the outer diameter surface of the split sleeve, the elastic body can be positioned and prevented from coming off.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The roller with a torque limiter of the first embodiment shown in FIGS. 1 and 2 is a combination of a roller part 1 and a torque limiter part 2 and is used by being fitted to the outer periphery of the shaft 3.

  The roller portion 1 is configured by fitting a rubber roller 5 around the roller body 4, and engagement recesses 6 and 6 for the torque limiter portion 2 are provided on one end surface of the roller body 4. The roller unit 1 is fitted to the shaft 3 so as to be rotatable.

  The torque limiter portion 2 is fitted into an annular boss portion 7 that is abutted against one end surface of the roller body 4, a sleeve 8 that is coaxially provided on one surface thereof, and an outer diameter surface of the sleeve 8. It consists of a ring-shaped elastic body 9. The boss 7 is provided with a pair of engaging convex portions 11 and 11 on the surface opposite to the sleeve 8 and is coupled in the rotational direction by being engaged with the engaging concave portions 6 and 6 described above. Coupled concentrically on the shaft 3.

  The sleeve 8 is provided with slits 12 which are opened at the distal end at regular intervals in the circumferential direction, and are divided into a plurality of strip-shaped sleeve pieces 13 by the slits 12. At the tip of each sleeve piece 13, a retaining projection 14 rising outward is provided. The sleeve 8 formed by the assembly of the boss portion 7 and the divided sleeve piece 13 is an integrally molded product of synthetic resin, and the sleeve 8 has contraction elasticity in the radial direction. The elastic body 9 is fitted to the outer diameter surface of the sleeve 8 and is prevented from being removed by the retaining protrusion 14.

  The elastic body 9 is made of a synthetic resin or metal, and is formed by a cylindrical spring that is cut off at one place in the circumferential direction by an axial slit 15. The inner diameter is formed slightly smaller than the outer diameter of the sleeve 8, thereby applying a radial force to the sleeve 8.

  As described above, the roller unit 1 and the torque limiter unit 2 combined as described above are inserted around the shaft 3 and positioned in the axial direction by E-shaped retaining rings 16 and 16 at both ends thereof. .

  The roller with a torque limiter of the first embodiment having the above configuration is used in a small printer such as a personal printer. When the load acting on the roller unit 1 is below a certain level, the roller unit 1 and the torque limiter unit 2 are The torque limiter unit 2 rotates integrally with a predetermined torque with respect to the shaft 3, but when the load exceeds a predetermined torque value, the torque limiter unit 2 idles with respect to the shaft 3. It idles with respect to the shaft 3, and transmission of torque is interrupted.

  In the above torque limiter, by setting the dimensions of the elastic body 9 to be constant, the radial force of the sleeve 8 becomes constant, and therefore the torque value also becomes constant. For this reason, it is not necessary to adjust torque after assembly.

  Further, by using a self-lubricating material as the synthetic resin constituting the sleeve 8, no lubricant is required, and a case member for preventing the lubricant from scattering, leaking, etc. is unnecessary.

  The elastic body 9 is a single cylindrical spring that is cut off at one place in the circumferential direction by an axial slit 15. In addition, the elastic body 9 is shown in FIG. As described above, a structure in which similar cylindrical springs are stacked in multiple layers, or a coil spring as shown in FIG. 4B can be used. According to these, even higher torque can be generated. The point of the modification of the elastic body 9 is the same in the following embodiments.

  Next, in the rotating body with a torque limiter according to the second embodiment shown in FIGS. 5 and 6, the roller portion 1 and the torque limiter portion 2 are integrated. That is, the sleeve 8 is integrally formed in one end portion of the roller body 4 in a concentric state. In other words, the boss portion 7 of the torque limiter portion 2 is integrated with the end surface of the roller body 4. Other configurations and operations are the same as those in the first embodiment.

  The rotating body with a torque limiter of the third embodiment shown in FIGS. 7 and 8 is the same as that of the second embodiment in that the roller portion 1 and the torque limiter portion 2 are integrated. The difference is that the positioning retaining rings 16 and 16 are omitted, and a positioning claw 17 is provided on the inner peripheral surface of the distal end portion of each sleeve piece 13 constituting the sleeve 8. By locking the positioning claw 17 in the locking groove 18 of the shaft 3, the position with respect to the shaft 3 is determined.

  In the case of the fourth embodiment shown in FIGS. 9 and 10, an arm 20 is provided to protrude in the axial direction around the shaft hole 19 on the surface of the roller body 4 opposite to the sleeve 8 side, and the inner surface of the tip portion thereof. Is provided with a positioning claw 17 and locked in a locking groove 18 of the shaft 3. Others are the same as in the case of the third embodiment.

  The rotating body with a torque limiter according to each embodiment described above can meet the demand for miniaturization and unitization, but still has the following problems. That is, the roller body 4 and the sleeve 8 divided from the above are molded by resin, but it is necessary to provide a portion for molding the required number of slits 12 in the molding portion of the sleeve 8 of the die. Since the molding part of the slit 12 is a thin part sandwiched between the cavities on both sides thereof, a defect such as a defect occurs at the time of molding, which causes a shortened life of the mold.

  In order to solve this problem, the width of the slit 12 should be set large. However, when the width of the slit 12 is increased, as shown in FIG. 11, when the elastic body 9 (coil spring) is assembled around the sleeve 8, the distal end portion of the sleeve 8 is reduced in diameter by the binding force (inner diameter φA). See), smaller than the outer diameter φB of the shaft 21. For this reason, it becomes difficult to insert the shaft 21 from the sleeve 8 side.

  Further, when the elastic body 9 having a strong spring force is used to generate a large torque, it is difficult to expand the diameter of the elastic body 9 when the shaft 21 is inserted into the sleeve 8. 21 becomes difficult to insert.

  Further, when the rotating body 22 is a rubber roller, since the shape is long in the axial direction, the hole diameter through which the shaft 21 passes is also long. For this reason, it is necessary to maintain the hole diameter tolerance with the entire length of the hole, so that it is difficult to mold the mold, and it takes time and cost to manufacture the mold for correcting the mold.

  The fifth embodiment described below solves the above problem. That is, the fifth embodiment shown in FIGS. 12 to 14 relates to a rubber roller with a torque limiter, in which a torque limiter 32 is integrally attached to one end of the rubber roller 31. The rubber roller 31 covers a rubber sleeve 36 on the outer diameter surface of a sleeve-like roller body 35 having flanges 33 and 34 at both ends of the outer diameter surface. Further, radial bearings 37 and 38 are provided at both ends of the inner diameter surface of the roller body 35. As shown in FIG. 12, one radial bearing 37 is formed by arranging bearing convex portions 39 having a width a at a constant pitch in the circumferential direction with a distance a '. The other radial bearing 38 is formed by arranging bearing convex portions 41 having a width b at a predetermined pitch in the circumferential direction with a distance b '. In the illustrated case, the relationship is set to a <b, a ′> b ′.

  The interval a 'is such a size that the bearing convex portion 41 having the width b fits without any gap, and the interval b' is such a size that the bearing convex portion 39 having the width a can fit without any gap. The positional relationship in the circumferential direction between both bearing convex portions 39 and 41 is such that the phase is shifted in the circumferential direction by one pitch. By setting such a positional relationship, undercutting can be avoided, so that the inner surface of the roller body 35 can be molded.

  Each of the bearing convex portions 41 forming the radial bearing 38 is extended in the axial direction while maintaining the width b and the interval b ′, and the portion of the width becomes the divided sleeve piece 42. The portion becomes the slit 43. A split sleeve 44 is formed by the split sleeve pieces 42 and the slits 43. The width of the distal end portion of each divided sleeve piece 42 is widened at the inclined step portions 45, 45 on both sides, and when the coil spring 46 is assembled to the outer diameter surface of the divided sleeve 44 as described later, Both sides of the split sleeve piece 42 abut each other to form an annular portion 47 as a whole.

  The inner surface of the ring portion 47 has a taper in the direction of expanding outward, and serves as a guide when the shaft 48 is inserted. Further, a protrusion 49 for preventing the coil spring 46 from coming off is provided on the outer diameter surface of the ring portion 47. The outer surface of the protrusion 49 is also tapered, and serves as a guide when the coil spring 46 is assembled.

  As shown in FIG. 14, the shape of the split sleeve 44 at the time of molding is such that each split sleeve piece 42 is opened outward so that the tip side is expanded. As a result, the slit 43 is also widened and the tip is also in a separated state. For this reason, the thickness of the molding part of the slit 43 of the molding die which molds this becomes large, and the fear of the mold defect is eliminated.

  The coil spring 46 is formed by winding a rectangular spring wire (however, a round spring wire can also be used), and the hooks 51 and 52 at both ends thereof are directed toward the outer diameter (radially outward). ) Is bent. The fraction x of the winding (see FIG. 13B) is appropriately set within the range of more than zero and less than half a circle, but in the case of the figure, it is set to a quarter circle. By providing such a fraction x, an inferior arc L1 (= fraction x) and a dominant arc L2 are formed between both hooks 51, 52, and the hooks 51, 52 approach in such a direction that the minor arc L1 becomes smaller. When a force is applied so that the coil spring 46 is elastically expanded in diameter.

  The coil spring 46 is assembled to the outer diameter surface of the divided sleeve 44 and the diameter thereof is reduced, and as described above, the ends of the divided sleeve pieces 42 are butted together in the circumferential direction to form the annular portion 47. The hook 51 on the side of the collar 34 of the coil spring 46 is engaged with a fan-shaped projection 53 provided on the outer end surface of the collar 34 (see FIG. 13A), and the other hook 52 is also the same as the collar 34. Is engaged with a pin-like protrusion 54 projecting from the outer end surface of the.

  As described above, the coil spring 46 is assembled around the split sleeve 44, and the split sleeve 44 is reduced in diameter by its binding force. In the state shown in FIGS. The relationship between the diameter φB and the inner diameter φC of the split sleeve 44 is φB <φA> φC. For this reason, it is easy to insert the tip of the shaft 48 into the ring portion 47, and the difference between φB and φC becomes a closing allowance for the shaft 48. The shaft 48 is inserted while expanding the diameter by the closing allowance, but when the insertion is difficult, an external force is applied so that both the hooks 51 and 52 of the coil spring 46 are close to the inferior arc L1 side. The diameter of the split sleeve 44 is increased to weaken the binding force.

  In this case, an external force may be directly applied to the hooks 51 and 52. However, by giving flexibility to the pin-shaped protrusion 54 shown in the figure, by pushing it toward the other hook 51 with the fingertip, The hook 52 can be moved to the hook 51 side, and the diameter of the coil spring 46 can be increased.

  The shaft 48 thus inserted is rotatably supported by two radial bearings 37 and 38 on the inner surface of the roller body 35.

  The above fifth embodiment shows an example in which the coil spring 46 is used as the binding means of the portion of the split sleeve 44. However, instead of the coil spring 46, as shown in the modified examples of FIGS. Alternatively, the required number of spring-shaped C-shaped rings 55 may be used. By appropriately changing the number, the binding force can be finely adjusted step by step. Also, as shown in FIG. 16, if the notch width X of the C-shaped ring 55 is set smaller than the wire diameter Y, there is an advantage that the C-shaped rings 55 are not easily entangled with each other. In this case, the other configurations are the same as those described above except that the protrusions 53 and 54 described above are not necessary.

  The rubber roller with a torque limiter of the fifth embodiment is as described above, and the torque between the shaft 48 and the rubber roller 31 is determined by the binding force of the coil spring 46 or the C-shaped ring 55 that reduces the diameter of the split sleeve 44. When the load applied to the rubber roller 31 exceeds the torque value, idling occurs and torque transmission is interrupted.

  In addition, although the above 5th embodiment described the case where it applies to a rubber roller, this invention is applicable to various rotary bodies other than this.

  Next, the sixth embodiment shown in FIGS. 17 and 18 is the first embodiment described above (see FIGS. 1 to 4), and the seventh embodiment shown in FIGS. 19 and 20 is the second embodiment described above. Since the basic structure is common to the embodiment (see FIGS. 5 and 6), only the same parts are denoted by the same reference numerals and different structures are mainly described.

  In each of the sixth and seventh embodiments, the split sleeve 8 is divided into three parts, the three C-shaped rings 55 are used as the elastic bodies 9, and the root of the split sleeve 8 (first In the case of the sixth embodiment, a circumferential recess 56 is provided in the boss portion 7 and in the case of the seventh embodiment on the roller body 4 side, and each C-shaped ring 55 has a predetermined binding force in the recess 56. Common in terms of mounting. The reason why the divided sleeve 8 is divided into three parts, the reason why the C-shaped ring 55 is attached to the base part of the divided sleeve 8, the reason why the recessed part 56 is provided in the attached part, etc. will be described next.

(1) Reason for dividing the divided sleeve 8 into three:
In the case of the first to fifth embodiments described above, the dividing sleeve 8 is divided into six. In the case where the same shaft diameter is applied, the case of 6 divisions and the case of 3 divisions are shown in FIGS. 21A and 21B. Assuming that the slits 12 are constant, the relationship between the widths (ie, circumferential lengths) a and b of the divided sleeve pieces 13 is naturally a <b.

  FIG. 22 (in the case of 6 divisions) and FIG. 23 (in the case of 3 divisions) show the results of experiments on the magnitude of torque fluctuation due to the difference in the circumferential length of the divided sleeve pieces 13 in the case of the shaft diameter 6φ. Consideration is based on these experimental results.

  In the case of FIGS. 22A and 22B, in which the circumferential length of the divided sleeve piece 13 is relatively short, the rigidity in the circumferential direction is low, so that the torque limiter rotates relative to the shaft to generate torque. At this time, the division sleeve 8 is bent in the circumferential direction due to the shaft rotation. As a result, the posture of the split sleeve 8 changes before and after relative rotation with respect to the shaft, and the binding force between the shaft and the split sleeve 8 and thus the frictional force changes, and the generated torque changes greatly (FIG. 22 (c)). Torque change A). In this case, the circumferential length a of each divided sleeve piece 13 is 2.5 mm, and the axial length c is 8.5 mm. a / c is 0.29.

  On the other hand, in the case of FIGS. 23A and 23B in which the circumferential length of the divided sleeve piece 13 is relatively long, the rigidity in the circumferential direction is increased, so that the divided sleeve 8 rotates relative to the shaft. Even so, the shape is stable and the contact with the shaft is stable. Therefore, the torque change is also reduced (see torque change B in FIG. 23C). In this case, the circumferential length b of each divided sleeve piece 13 is 5.2 mm, and the axial length d is 5.7 mm. b / d is 0.912. This ratio is considered to exhibit the same effect within the range of 0.9 ± 0.1.

  Thus, in the shape of each divided sleeve piece 13 of the divided sleeve 8, the ratio of the circumferential length to the axial length is set to 0.9 ± 0.1, whereby the axial length of the divided sleeve piece 13 is set. In addition, since the circumferential length is sufficiently large, rigidity in the rotational direction can be exhibited.

(2) Reason for attaching the C-shaped ring to the base of the split sleeve:
When a spring such as a C-shaped spring 55 is mounted at a position away from the root of the split sleeve 8 (see FIGS. 24A and 24B), when the torque limiter rotates relative to the shaft, In addition to the binding force on the shaft, a moment load is easily generated, which causes the split sleeve 8 to bend. For this reason, the posture of the split sleeve 8 with respect to the shaft changes before and after the relative rotation, the binding force between the shaft and the split sleeve 8, and hence the frictional force, changes, and a relatively large change C of the generated torque occurs. FIG. 24 (c)). On the other hand, when a spring 55 such as a C-shaped spring is attached to the base of the split sleeve 8 (see FIGS. 25 (a) and 25 (b)), generation of moment force on the split sleeve 8 can be suppressed, and generated torque Change D (see FIG. 25C) becomes relatively small.

(3) Reason for providing a recess in the mounting part of the C-shaped ring:
By providing the recessed portion 56 at the mounting portion of the C-shaped ring, that is, the base of the split sleeve, it is possible to position the spring 55 such as a C-shaped spring and to prevent it from coming off.

(4) Other:
As described above, the circumferential length of the divided sleeve piece 13 is relatively increased to increase the rigidity in the circumferential direction, while the radial deflection of each divided sleeve piece 13 is improved to improve the C-shaped spring 55. The ease of incorporation into the split sleeve 8 can be improved.

Exploded perspective view of the first embodiment Cross-sectional view of the above Sectional view along line III-III in Fig. 2 (A) The perspective view of the modification of an elastic body same as the above, (b) The perspective view of the other modification of an elastic body same as the above. Sectional view of the second embodiment Perspective view showing part of the above Sectional view of the third embodiment Perspective view showing part of the above Sectional view of the fourth embodiment Perspective view showing part of the above Cross section for explaining the problem Sectional drawing of 5th Embodiment (A) Perspective view of the above, (b) Front view of the coil spring of the same. An exploded perspective view showing a part of the above in section Sectional drawing which shows a part of modification same as the above Exploded perspective view showing part of the above Sectional drawing of 6th Embodiment Exploded perspective view Sectional view of the seventh embodiment Exploded perspective view (A) (b) Sectional view for comparison of split sleeves (A) Partial side view of test object, (b) Front view same as above, (c) Graph of experimental results (A) Partial side view of test object, (b) Front view same as above, (c) Graph of experimental results (A) Partial side view of test object, (b) Front view same as above, (c) Graph of experimental results (A) Partial side view of test object, (b) Front view same as above, (c) Graph of experimental results

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Roller part 2 Torque limiter part 3 Shaft 4 Roller main body 5 Rubber roller 6 Engaging recessed part 7 Boss part 8 Sleeve 9 Elastic body 11 Engaging recessed part 12 Slit 13 Dividing sleeve piece 14 Detachment protrusion 15 Slit 16 Retaining ring 17 Positioning claw 18 Locking groove 19 Shaft hole 20 Arm 21 Shaft 31 Rubber roller 32 Torque limiter 33 Brim 34 Brim 35 Roller body 36 Rubber sleeve 37 Radial bearing 38 Radial bearing 39 Bearing convex portion 41 Bearing convex portion 42 Split sleeve piece 43 Slit 44 Split sleeve 45 Inclined Step part 46 Coil spring 47 Ring part 48 Shaft 49 Projection 51 Hook 52 Hook 53 Projection 54 Projection 55 C-shaped ring 56 Concave

Claims (4)

  A torque limiter is attached to one end of the rotating body, and the torque limiter is configured by assembling a spring around a split sleeve divided by a plurality of axial slits, and a required torque is provided between the split sleeve and the shaft. In the rotating body with a torque limiter generated, the divided sleeve is formed of at least two divided sleeve pieces, and the ratio of the circumferential length to the axial length of each sleeve piece is 0.8 to 1.0. A rotating body with a torque limiter, characterized in that   The rotating body with a torque limiter according to claim 1, wherein the spring is assembled at a position offset from the rotating body side of the split sleeve.   The rotating body with a torque limiter according to claim 2, wherein a circumferential recess is provided at a spring assembly position of the split sleeve.   4. The rotating body with a torque limiter according to claim 1, wherein the axial length of the divided sleeve is greater than the axial diameter. 5.

Images