JP2005114132A - One-way torque limiter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To aim at the reduction of product cost by improving a torque limiter mechanism in a one-way torque limiter. <P>SOLUTION: The one-way torque limiter incorporates a one-way clutch 2 and a torque limiter 3 in the radial direction in a housing 1, and the torque of specified value is produced in the above torque limiter 3 when engaging the above one-way clutch 2. In the limiter, the above torque limiter 3 is formed by O-ring 18 that can be obtained cheaply as a commercial item. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a unidirectional torque limiter having a function of transmitting a torque of a predetermined magnitude in a certain rotational direction and blocking transmission of torque in the opposite rotational direction.

  The one-way torque limiter has been used in the hinges and other parts of office machines, etc., and has a structure in which a concentric one-way clutch and torque limiter are incorporated in the inner circumference of the housing in the radial direction. In general, a torque limiter is disposed on the inner diameter side, and a predetermined torque is generated by causing a slip on the outer diameter surface of the shaft (see Patent Document 1), and a torque limiter is disposed on the outer diameter side, There is a type in which a predetermined torque is generated by causing a slip on the outer diameter surface of the one-way clutch (see Patent Document 2).

In any of the above cases, the torque limiter is formed by a coil spring, and when the one-way clutch is engaged and rotated in the torque transmission direction, the coil spring is rotated in the direction of rewinding so as to generate a predetermined torque. I have to. The magnitude of the generated torque is largely due to the elastic coefficient of the coil spring in addition to the coefficient of friction of the member that is the object of sliding contact.
No. 7-23626 JP 2001-208108 A

  In the conventional one-way torque limiter in which the torque limiter is formed by a coil spring, a plurality of types of coil springs having different elastic coefficients must be prepared in the case of producing different torques. For this reason, in the manufacturing process of the coil spring, a plurality of types of jigs corresponding to the wire diameters are required to mold the types having different elastic coefficients, which causes high costs. Further, during use, sealing means such as enclosing with a casing or closing with a sealing member is necessary so that dust, foreign matter or the like does not enter the torque limiter, which is also a cause of high cost.

  Therefore, an object of the present invention is to provide an inexpensive unidirectional torque limiter by reducing the cost and eliminating the sealing means.

  In order to solve the above-described problems, the present invention incorporates a one-way clutch and a torque limiter in a concentric state on the inner periphery of the housing in the radial direction so that one of them is on the inner diameter side and the other is on the outer diameter side. When the torque limiter is incorporated on the inner diameter side, the shaft is subject to sliding contact, and when the torque limiter is incorporated on the outer diameter side, the one-way clutch is subject to sliding contact, and the torque limiter slips when the one-way clutch is engaged. In the unidirectional torque limiter that generates a predetermined magnitude of torque at the contact portion, a configuration is adopted in which the torque limiter is formed by an O-ring.

  According to the above configuration, when the load torque is larger than the set torque value of the torque limiter, the O-ring forming the torque limiter slips between the mating member and generates a predetermined magnitude of torque. In addition to generating torque, the O-ring also functions as a seal member that prevents dust and the like from entering the torque limiter and prevents leakage of the lubricant enclosed therein. The set torque value can be changed by using O-rings having different elastic coefficients, and such O-rings can be easily obtained as commercial products.

  As the shape of the housing, an end wall can be provided at one end portion thereof, and the inner end surfaces of the one-way clutch and the torque limiter can be closed by the end wall. The end wall closes one end face of the internal one-way clutch and the torque limiter, and the inner diameter surface of the end wall contacts the shaft to perform a bearing action.

  In addition, if the structure which interposed the rolling bearing in the internal diameter surface of the end wall will be adopted, it will become a high-speed rotation specification.

  Further, it is possible to adopt a configuration in which a plurality of O-rings of the torque limiter are arranged in the axial direction and a lubricant is sealed between the O-rings. According to this configuration, leakage of the lubricant is prevented by the O-ring, and good wear resistance is exhibited over a long period of time for the O-ring and other parts.

  Furthermore, it is possible to adopt a configuration in which a wave ring spring that forms the torque limiter together with the O-ring is arranged in parallel with the O-ring that forms the torque limiter and closer to the end wall than the O-ring. Corrugated ring springs generate torque by slipping in the same manner as O-rings, and supplement torque that is insufficient with O-rings alone. Since this wave ring spring is always used together with the O-ring and is arranged inside the O-ring, the sealing action by the O-ring is not disturbed.

  As described above, the unidirectional torque limiter according to the present invention uses an O-ring as a torque generating member for generating a predetermined set torque value. O-rings of various standards are inexpensive. And is easier to assemble than a spring or the like, which can contribute to product cost reduction.

  In addition, the O-ring can prevent the lubricant from leaking out due to the original sealing action, and can improve the durability of the product by preventing entry of dust and the like.

  The best mode for carrying out the present invention will be described below as first to fourth embodiments with reference to the accompanying drawings.

  The one-way torque limiter of the first embodiment shown in FIGS. 1A to 1B is incorporated in the housing 1, the one-way clutch 2 incorporated in the inner diameter side thereof, and the outer diameter side thereof. It consists of a unit with the torque limiter 3. One end of the housing 1 is opened, and an end wall 4 is provided at the other end. An inner diameter surface of the end wall 4 serves as a bearing 5. One end face of the one-way clutch 2 and the torque limiter 3 is closed by the end wall 4. The shaft 6 has a stepped portion 7, and the unidirectional torque limiter is positioned by contacting the inner surface of the end wall 4 against the stepped portion 7, and the end wall 4 is in sliding contact with the small diameter portion 8 (see FIG. 1 (b)).

  The one-way clutch 2 is engaged with the large-diameter portion 11 of the shaft 6. In the one-way clutch 2, a required number of pockets 13 are formed on the inner diameter of the clutch wheel 12 at a constant interval in the circumferential direction, and a roller 14 is accommodated in each pocket 13. A wedge-shaped portion 15 is formed between the bottom surface of the pocket 13 and one of the inner end surfaces between the pocket 13 and the shaft 6. A spring 16 is interposed between the roller 14 and the other end, and the roller 14 is lightly urged in the narrow direction of the wedge-shaped portion 15 to stabilize the operation of the roller 14. When the shaft 6 rotates in the direction of narrowing the wedge angle of the wedge-shaped portion 15 with respect to the clutch wheel 12 (see the arrow A in FIG. 1A), the roller 14 moves in that direction and becomes engaged and engages. It becomes a joint state. On the other hand, when the shaft 6 rotates in the opposite direction, the roller 14 moves in the opposite direction against the spring 16 to release the bite and release the state. In the released state, the roller 14 is free to roll with respect to the shaft. When the shaft 6 is fixed, the roller 14 is engaged when the clutch wheel 12 is rotated in the direction of increasing the wedge angle (see arrow B), and is released when it is rotated in the opposite direction. A seal member 17 is attached to the inner surface of the outer end portion of the clutch wheel 12.

  The torque limiter 3 is provided between the outer diameter surface of the clutch wheel 12 and the inner diameter surface of the housing 1. The torque limiter 3 is formed by two O-rings 18 that are arranged on the outer diameter surface of the clutch wheel 12 at an interval in the axial direction. Each O-ring 18 is attached so that the outer diameter surface of the clutch wheel 12 can be slidably contacted and can be slidably contacted with the outer diameter surface with a certain elasticity. Further, the outer peripheral surface is in contact with the inner diameter surface of the housing 1. A rib 19 for preventing the outer O-ring 18 from slipping out is provided at the open end of the housing 1 over the entire circumference.

  The unidirectional torque limiter having the above configuration is not suitable for high-speed rotation because the bearing 5 is formed on the inner diameter surface of the end wall 4. For this reason, it is used for low-speed rotation.

  The one shown in FIG. 1C is suitable for high-speed rotation, and the end wall 4 of the housing 1 is formed shorter than the above case, and the inner end surface receives the outer surface of the inner O-ring 18. A ball bearing 21 in contact with the stepped portion 7 is interposed between the inner diameter surface of the end wall 4 and the small diameter portion 8 of the shaft 6, and the inner surface of the ball bearing 21 receives the inner surface of the one-way clutch 2. It is like that.

  The unidirectional torque limiter of the first embodiment is configured as described above, and the operation thereof will be described next. There are cases where the housing 1 is used on the load side and the shaft 6 is used on the drive side, and conversely, the housing 1 is used on the drive side and the shaft 6 is used on the load side. Now, the case where the shaft 6 is on the drive side will be described. In FIG. 1A, when the shaft 6 rotates in the narrow direction of the wedge angle as shown by the arrow A, the roller 14 of the one-way clutch 2 is wedge-shaped. 15, the clutch wheel 12 rotates integrally with the shaft 6. When the load torque is smaller than the set torque value of the torque limiter 3, the drive torque is transmitted to the load via the torque limiter 3. When the load torque is larger than the set torque value, slip occurs in the portion of the O-ring 18 of the torque limiter 3, and a predetermined set torque is generated and transmitted to the load.

  When the shaft 6 rotates in the direction opposite to the arrow A, the roller 14 moves in the direction of increasing the wedge angle, so that the one-way clutch 2 is released and the transmission of torque to the load is interrupted.

  When the shaft 6 rotates at a low speed, the one shown in FIG. 1 (b) for low-speed rotation is used. When the shaft 6 rotates at a high speed, the ball bearing 21 shown in FIG. 1 (c) is interposed. used.

  In any of the above cases, it is desirable to enclose a lubricant such as grease between the inner and outer O-rings 18 and 18 forming the torque limiter 3. The sliding portion of the O-ring 18 is lubricated by the enclosed lubricant to prevent the progress of wear. Further, the inner and outer O-rings 18 and 18 prevent dust and other foreign substances from entering the inside thereof, and at the same time prevent leakage of the lubricant.

  When the shaft 6 is on the load side and the housing 1 is on the drive side, when the housing 1 rotates in the opposite direction (see arrow B), the load torque exceeds the set torque value of the torque limiter 3. Then, the clutch wheel 12 of the one-way clutch 2 rotates at the set torque value, the roller 14 engages with the wedge-shaped portion 15 and enters the engaged state, and torque is transmitted, and the shaft 6 rotates in the direction of arrow B to the load. The set torque value is transmitted. When the rotation direction of the housing 1 is opposite to the above, the one-way clutch 2 is released and torque transmission is interrupted.

  In order to stabilize the position of each O-ring 18 of the torque limiter 3, as shown in FIGS. 2A and 2B, a shallow positioning groove 22 is formed in the sliding contact portion of the outer peripheral surface of each O-ring 18. , 22 may be provided. Providing such positioning grooves 22 and 22 is the same as in other embodiments described later.

  The second embodiment shown in FIGS. 3A to 3C is different from the above case in that the relationship of the combination of the one-way clutch 2 and the torque limiter 3 is reversed. All other configurations are the same.

  That is, in this case, the inner and outer two O-rings 18 and 18 forming the torque limiter 3 are interposed between the clutch wheel 12 of the one-way clutch 2 and the large-diameter portion 11 of the shaft 6, and each O-ring 18. Uses the outer diameter surface of the large-diameter portion 11 of the shaft 6 as the object of sliding contact. The clutch wheel 12 is provided with a required number of pockets 13 on its outer diameter surface, and a wedge-shaped portion 15 is formed between the bottom surface of each pocket 13 and the inner diameter surface of the housing 1. Since the operation is the same, the description is omitted.

  The third embodiment shown in FIGS. 4A to 4C is arranged on the inner side (on the end wall 4 side) of the two O-rings 18 and 18 forming the torque limiter 3 in the first embodiment. A wave ring spring 18 ′ is attached instead of the O ring 18. The corrugated ring spring 18 ′ is obtained by giving a large number of corrugated irregularities to a strip-shaped leaf spring at a constant pitch, curving into a ring shape, and butting both ends. You may use the tolerance ring containing the part which is a ring-shaped spring which provided the unevenness | corrugation of the waveform with a fixed pitch. Other configurations are the same as those of the first embodiment.

  By using such a corrugated ring spring 18 ', a larger torque can be generated than when only the O-ring 18 is used, and by leaving the O-ring 18 arranged outside, a sealing action can be achieved. It can be demonstrated. Since other operations are the same as those in the first embodiment, description thereof is omitted.

  The fourth embodiment shown in FIGS. 5A to 5C is arranged on the inner side (on the end wall 4 side) of the two O-rings 18 and 18 forming the torque limiter 3 in the second embodiment. Instead of the O-ring 18, a wave ring spring 18 ′ is mounted. The wave ring spring 18 'is the same as that described in the third embodiment. Also in this case, compared with the case where only the O-ring 18 is used, a large torque can be generated, and the sealing action can be exhibited by leaving the O-ring 18 disposed outside. Since other operations are the same as those in the second embodiment, description thereof is omitted.

(A) Cross-sectional view of Example 1, (b) Cross-sectional view taken along line bb of (a), (c) Cross-sectional view of a modification of Example 1 (A) Partial sectional view of a modification of the first embodiment, (b) Partial sectional view of another modification of the first embodiment. (A) Cross-sectional view of Example 2, (b) Cross-sectional view taken along line bb of (a), (c) Cross-sectional view of a modification of Example 2 (A) Cross-sectional view of Example 3, (b) Cross-sectional view taken along line bb of (a), (c) Cross-sectional view of a modification of Example 3 (A) Cross-sectional view of Example 4, (b) Cross-sectional view taken along line bb of (a), (c) Cross-sectional view of a modification of Example 4

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 One-way clutch 3 Torque limiter 4 End wall 5 Bearing 6 Shaft 7 Step part 8 Small diameter part 11 Large diameter part 12 Clutch ring 13 Pocket 14 Roller 15 Wedge-shaped part 16 Spring 17 Seal member 18 O ring 18 'Wave ring spring 19 Rib 21 Ball bearing 22 Positioning groove

Claims (5)

  A concentric one-way clutch and torque limiter are built in the inner circumference of the housing in the radial direction so that one is on the inner diameter side and the other is on the outer diameter side. If the torque limiter is installed on the inner diameter side, the shaft slips. When the one-way clutch is to be contacted and incorporated on the outer diameter side, the one-way clutch is subject to sliding contact, and a predetermined magnitude of torque is generated at the sliding contact portion of the torque limiter when the one-way clutch is engaged. In the unidirectional torque limiter, the torque limiter is formed by an O-ring.   The one-way torque limiter according to claim 1, wherein an end wall is provided at one end of the housing, and an inner wall of the one-way clutch and the torque limiter is closed by the end wall.   The unidirectional torque limiter according to claim 2, wherein a rolling bearing is interposed on an inner diameter surface of the end wall.   4. The unidirectional torque limiter according to claim 1, wherein a plurality of O-rings of the torque limiter are arranged in the axial direction, and a lubricant is sealed between the O-rings. 5.   5. A wave ring spring that forms the torque limiter together with the O-ring is disposed in parallel with the O-ring that forms the torque limiter and closer to the end wall than the O-ring. The unidirectional torque limiter according to any one of the above.

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