JP2005121145A - Torque limiter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact torque limiter capable of being easily manufactured, sufficiently supplying a lubricant and achieving stable performance. <P>SOLUTION: In this torque limiter wherein an external member 2 is relatively rotatably fitted to an internal member 1, an elastic member 3 is mounted in a state of being kept into contact with an outer-diameter face of the internal member 1 with a desired pressure, the co-rotation of the elastic member 3 and the internal member 1 closely kept into contact with the elastic member 3 is prevented by engaging a slit part 11 of the elastic member 3 with a hook part 8 of the external member 2, and the specific torque is generated by the friction of the contact part, a plurality of C-shaped springs 10 which can be worked with high accuracy are used as the elastic member 3, and the outer-diameter face of the internal member 1 closely kept into contact with the C-shaped springs 10, is provided with a groove 28 for supplying the lubricant. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a torque limiter used in a paper transport unit or the like in office equipment such as a copying machine or a printer.

  As a torque limiter used for office equipment as described above, the present applicant, as shown in Patent Document 1 below, fits an external member on an internal member so as to be relatively rotatable, and a required outer diameter surface of the internal member. A cylindrical spring is attached with a pressure contact force, and the slit portion of the cylindrical spring is engaged with the hook portion of the external member to prevent the cylindrical spring and the internal member from rotating together. Proposes something that generates.

The torque limiter configured as described above uses a cylindrical spring having a large contact surface with the internal member to generate torque, so that it is compact but can be increased in torque, and the cylindrical spring can be bent by a thin plate. Therefore, it can be easily manufactured at low cost.
JP 2002-250361 A (first embodiment, FIGS. 1 and 2)

  However, in the torque limiter using a cylindrical spring as described above, it is difficult to mold the cylindrical spring so that the inner diameter has a predetermined dimension over the entire length in the axial direction, and the dimensional error of the inner diameter of the cylindrical spring is large. Therefore, there is a problem that the pressure contact force against the internal member is difficult to stabilize.

  Also, when rotating at a high speed or when a large torque is applied, if the rotation continues, the lubricating oil in the contact portion between the cylindrical spring and the internal member will be insufficient, causing abnormal noise, or in the worst case, seizing. There is a fear.

  Therefore, an object of the present invention is to provide a compact torque limiter that is easy to manufacture, sufficiently supplied with lubricating oil, and capable of obtaining stable performance.

  In order to solve the above problems, the present invention is such that an external member is fitted to an internal member so as to be relatively rotatable, and an elastic member is attached so as to contact the outer diameter surface of the inner member or the inner diameter surface of the outer member with a required pressure, By engaging the slit portion of the elastic member with the hook portion of the external member or the internal member, the elastic member and the internal member or the external member to which the elastic member is pressed are prevented from co-rotating. In a torque limiter that generates torque, a plurality of C-shaped springs that are easy to process with high accuracy are used as the elastic member, and lubricating oil is supplied to the outer diameter surface of the inner member or the outer diameter surface of the outer member that the C-shaped spring is in pressure contact with. For this purpose.

  The groove is preferably engraved in a spiral shape and the width of the groove is set to ¼ or less of the width of the C-shaped spring. The spiral groove may be formed by forming a cylindrical surface by forging or sintering, then forming a screw on the cylindrical surface by rolling, and scraping off the top of the screw. In addition, the groove may be formed in a linear shape in the axial direction.

  As described above, the torque limiter according to the present invention uses a plurality of C-shaped springs with excellent machining accuracy and linear press contact portions as elastic members for generating torque, so that it rotates in either the left or right direction. However, the pressure contact force is stabilized, a predetermined torque can be obtained, and a sufficient torque can be generated while being compact.

  In addition, since a groove for supplying lubricating oil is provided on the outer diameter surface of the inner member or the inner diameter surface of the outer member to which the C-shaped spring is in pressure contact, sufficient lubricating oil is supplied to the pressure contact portion, generating abnormal noise and seizing. Is prevented. Further, this groove also functions as a foreign matter accumulation such as wear powder of parts, and damage of the pressure contact surface and abnormal wear due to the foreign matter are prevented.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment] A first embodiment shown in FIGS. 1 and 2 includes a cylindrical inner member 1, an outer member 2 fitted to the inner member 1 so as to be relatively rotatable, and an outer portion of the inner member 1. The elastic member 3 is mounted so as to come into contact with the radial surface with a required pressure, and the lid 4 closes one end of the outer member 2 outside the inner member 1.

  Engagement recesses 5 are provided at two locations on one end of the internal member 1, and a pin in the radial direction of a shaft (not shown) inserted through the internal member 1 is engaged with the engagement recess 5. Further, a spiral groove 28 is provided on the outer diameter surface of the inner member.

  A fitting portion 6 that rotatably supports the internal member 1 is provided inside one end portion of the external member 2, and an engaging projection 7 that is used for connecting an external structure is provided outside the fitting portion 6. . A hook portion 8 extending in the axial direction is formed on the inner diameter surface of the outer member 2, and a fitting groove 9 of the lid 4 is formed on the inner diameter surface of the open end portion of the outer member 2.

  The elastic member 3 includes four C-shaped springs 10 formed by bending bar members, and each C-shaped spring 10 is provided with a slit portion 11 at one location. The slit portion 11 engages with the hook portion 8 of the external member 2. In addition, the cross-sectional shape of the C-shaped spring 10 is a square cross section assuming a high torque type.

  The lid 4 has an insertion hole 12 for the inner member 1, and a rib 13 that is fitted into the fitting groove 9 of the outer member 2 is formed on the outer periphery of the lid 4.

  As described above, when the C-shaped spring 10 is used as the elastic member 3 for generating torque, the C-shaped spring 10 can be relatively easily manufactured with high accuracy in the size of the inner diameter pressed against the internal member 1. Since the pressure contact portion is linear, the pressure contact force is stable even if it rotates in either the left or right direction, and a predetermined torque can be generated. By using a plurality of C-shaped springs 10, it is compact. However, high torque can be achieved.

  Further, since the groove 28 for supplying lubricating oil is provided on the outer diameter surface of the internal member 1 to which the C-shaped spring 10 is in pressure contact, sufficient lubricating oil is supplied to the pressure contact portion to prevent generation of noise and seizure. The Further, the groove 28 also functions as a foreign substance accumulation such as wear powder of parts, and the damage of the pressure contact surface and the abnormal wear due to the foreign substance are prevented.

  The width of the groove 28 is preferably set to ¼ or less of the width of the C-shaped spring 10. If the width of the groove 28 is larger than this, abnormal noise may occur when the end face of the slit portion 11 of the C-shaped spring 10 falls into the groove 28.

  The spiral groove 28 as described above can be formed from a thread valley as shown in FIG. 3A in addition to a general cutting method. In this case, after the cylindrical surface is formed by forging or sintering, a screw is formed on the cylindrical surface by rolling, and as shown in FIG.

  In addition, as shown in FIG. 4, a plurality of the grooves 28 may be provided as a straight line in the axial direction. In this case, the groove 28 can be formed simultaneously with the production of the internal member 1 by forging or sintering, and post-processing is unnecessary, so that the cost can be suppressed.

[Second Embodiment] The second embodiment shown in FIGS. 5 and 6 includes an inner member 1, an outer member 2, and an elastic member 3. The outer member 2 includes an outer ring 14, a torque transmission member 15 as a gear, and the like. It is composed of

  The elastic member 3 includes four C-shaped springs 10 formed by bending bar members, and each C-shaped spring 10 is provided with a slit portion 11 at one location. In addition, the cross-sectional shape of the C-shaped spring 10 is a square cross section assuming a high torque type.

  The internal member 1 includes a shaft portion 16, a bearing portion 17, and a flange 18, and the shaft portion 16 is provided with a hook portion 8 that extends from the bearing portion 17 in the axial direction. At the base end portion of the shaft portion 16, a notch portion 19 is formed which engages both when connected to a structure (not shown) and prevents relative rotation thereof.

  The outer ring 14 is formed with one concave portion 20 on one end surface, and a concave groove 21 that prevents rotation of a structure (not shown) at four locations on the outer peripheral surface. A plurality of axial grooves 28 are formed on the inner diameter surface of the outer ring 14.

  Further, the torque transmission member 15 has a shaft hole 23 formed at the center of the gear portion 22, a bearing portion 24 protrudes in one direction from the outer periphery thereof, and a convex portion 25 is formed on the outer periphery of the bearing portion 24.

  The torque limiter assembled from the above members is mounted so that the C-shaped spring 10 is in contact with the inner diameter surface of the outer ring 14 with a required pressure, and the shaft of the inner member 1 is engaged so that the slit portion 11 is engaged with the hook portion 8. The part 16 is inserted into the inside of the C-shaped spring 10 from the front end side with an interval.

  One end of the outer ring 14 is supported by the bearing portion 17 of the inner member 1 so as to be rotatable relative to the inner member 1, and is prevented from coming off by a flange 18. Further, the shaft portion 16 of the inner member 1 is inserted into the shaft hole 23 of the torque transmission member 15 so as to be relatively rotatable, and the bearing portion 24 of the torque transmission member 15 is inserted into the other end portion of the outer ring 14, The recess 20 is engaged so that the outer ring 14 and the torque transmission member 15 rotate together.

  In this torque limiter, the engagement between the internal member 1 and the C-shaped spring 10 prevents the internal member 1 and the external member 2 from rotating together, and a constant torque is generated by the friction between the C-shaped spring 10 and the external member 2. Occur.

  In this way, when the C-shaped spring 10 is used as the elastic member 3 for generating torque, the C-shaped spring 10 can be manufactured relatively easily and accurately with the outer diameter dimension pressed against the outer member 2. Since the pressure contact portion to 2 is linear, the pressure contact force is stable even if it rotates in either the left or right direction, and a predetermined torque can be generated. By using a plurality of C-shaped springs 10, it is compact. Nevertheless, high torque can be achieved.

  Further, since the lubricating oil supply groove 28 is provided on the inner diameter surface of the outer ring 14 to which the C-shaped spring 10 is in pressure contact, sufficient lubricating oil is supplied to the pressure contact portion, thereby preventing abnormal noise and seizure. Further, the groove 28 also functions as a foreign matter accumulation such as wear powder of parts, and the pressure contact surface is prevented from being damaged or abnormally worn by the foreign matter.

  In addition, in this embodiment, since the outer ring 14 that generates torque directly contacts the outside air, the heat generated by the friction is efficiently dissipated, the temperature rise of the torque limiter is suppressed, and the life of the lubricant is extended.

Exploded perspective view of the first embodiment (A) Vertical side view of the assembled state of the above, (b) bb sectional view of (a) (A) Side view of internal member formed with grooves by thread rolling, (b) Partially enlarged side view showing the manufacturing process of the above Perspective view of internal member with axial grooves formed Exploded perspective view of the second embodiment (A) Vertical side view of the assembled state of the above, (b) bb sectional view of (a)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal member 2 External member 3 Elastic member 4 Lid 8 Hook part 10 C-shaped spring 11 Slit part 14 Outer ring 15 Torque transmission member 28 Groove

Claims (5)

  An external member is fitted to the internal member so as to be relatively rotatable, and an elastic member is mounted so as to contact the outer diameter surface of the inner member or the inner diameter surface of the outer member with a required pressure, and the slit portion of the elastic member is attached to the outer member or the outer member. In the torque limiter which prevents the co-rotation of the elastic member and the internal member or the external member to which it is pressed by engaging with the hook portion of the internal member, and generates a constant torque by the friction of the pressure contact portion, A torque limiter, wherein a plurality of C-shaped springs are used as the elastic member, and a groove is provided on the outer diameter surface of the inner member or the inner diameter surface of the outer member to which the C-shaped spring is pressed.   The torque limiter according to claim 1, wherein the groove is provided in a spiral shape.   The torque limiter according to claim 2, wherein the width of the groove is ¼ or less of the width of the C-shaped spring.   4. The torque limiter according to claim 2, wherein the spiral groove is formed by forging or sintering a cylindrical surface, forming a screw by rolling on the cylindrical surface, and scraping a top portion of the screw. Torque limiter characterized by being formed.   The torque limiter according to claim 1, wherein the groove is provided in a linear shape in the axial direction.

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