JP4993521B2 - Axial force-induced torque limiter - Google Patents

Description

  The present invention relates to an axial force-induced torque limiter. More specifically, by providing a mechanism that can reduce the limit transmission torque (maximum torque that can be transmitted) as the axial force increases, the axial force itself can be accurately controlled to the desired value, resulting in excellent axial characteristics. The present invention relates to a mold torque limiter.

  Conventionally, a torque limiter has been used as an overload prevention mechanism for an axial force in a device that pulls or pushes a load (hereinafter referred to as a linear motion device) by converting the rotational movement of a rotary element into an axial movement. Yes.

  As the torque limiter, there is provided a torque limiter that is provided in the drive unit of the rotating element so that when the set torque is reached, the friction surface slips and further torque transmission is disabled. As one type, for example, a friction surface slip type torque limiter disclosed in Japanese Utility Model Laid-Open No. 59-47127 and Japanese Patent Application Laid-Open No. 2001-107330 has been proposed. Further, when the set torque value is reached, the engagement members are disengaged from each other, and further torque transmission is disabled. For example, a ball as disclosed in Japanese Patent Application Laid-Open No. 2004-176856 There is provided a disengagement type torque limiter configured such that torque transmission is interrupted by disengagement between the first and second recesses and the concave groove.

  FIG. 26 shows a linear motion device a with a torque limiter in which a friction surface slip type torque limiter A is assembled to a linear motion device B. A nut b which is prevented from rotating by means not shown is rotated by a bearing not shown. The screw shaft c is screwed to a freely supported screw shaft c. The nut b is an example of an element that converts the rotational movement of the screw shaft c into the axial movement of the screw shaft c.

  A hub g having a flange f around one end of the cylindrical portion e is fixed to the base end portion d of the screw shaft c, and the front side portion of the cylindrical portion e has a male screw portion on the outer peripheral surface. The threaded cylinder portion k is provided with j. Further, an urging force adjusting nut m is screwed into the screw cylinder portion k, and a spur gear is connected to the cylindrical portion e via the bush n between the urging force adjusting nut m and the flange f. A shaped input gear p is rotatably attached. The input gear p is rotated forward and backward by a motor (not shown). A central portion q of the input gear p is held by friction plates r, r from inside and outside, and a disc spring s is interposed between the biasing force adjusting nut m and the outside friction plate r. When the urging force adjusting nut m is tightened as required, a holding force is generated by the friction plates r and r, and the maximum transmission torque value of the torque limiter A is set as required by the holding force. .

  However, when the load acting on the nut b is excessive, the transmission torque of the torque limiter A increases as the axial force of the screw shaft c of the linear motion device B increases, and the torque transmission remaining force (torque limiter) A difference between the maximum transmission torque of A and the torque according to the axial force of the linear motion device B) decreases. Then, the torque limiter A finally cannot transmit torque, and the input gear p slips and rotates in the circumferential direction. As a result, the load side and drive side devices can be protected.

  By the way, a part of the maximum transmission torque of this type of torque limiter is effectively used for generating the axial force of the linear motion device, and the loss torque of the support portion of the screw shaft c and the screw of the nut b are screwed. In addition to the torque corresponding to the frictional loss force at the joint, there are many parts consumed by torque or the like due to the moment of inertia of the rotating part during acceleration motion (when the screw shaft c starts rotating). In this way, there are various consumption torque factors, and variations occur in these factors. Therefore, the torque effectively used for generating the axial force is actually easy to change.

  The conventional torque limiter including this type of torque limiter has a limit transmission torque (maximum torque that can be transmitted) that is constant irrespective of the axial force, so that the load is in the vicinity of the limit transmission torque value. The torque difference (the difference between the limit transmission torque value of the torque limiter and the load torque) was small, and the torque difference was small in the vicinity of the load torque exceeding the limit transmission torque value. Moreover, as described above, since the torque that is effectively used for generating the axial force is likely to change, the torque transmission is interrupted with an axial force smaller than the desired axial force. However, there is a problem that it is difficult to perform torque interruption with high accuracy, for example, torque transmission cannot be interrupted even when a large axial force is reached.

  In order to prevent the torque transmission from being interrupted before reaching the axial force required for the linear motion device, the limit transmission torque is also set higher. However, when the limit transmission torque is set so high, as a result, the axial force at the time of interruption may become a value considerably higher than the desired axial force.

  This torque transmission interruption is preferably performed promptly when the axial force of the linear motion device exceeds the axial force value required by the linear motion device. From the viewpoint that the torque will increase as the axial force increases, the axial force is simply controlled using the torque.

  In short, the conventional torque limiter has a problem that the limit transmission torque does not necessarily correspond accurately with the desired axial force of the linear motion device, and the axial force cannot be controlled with high accuracy.

Japanese Utility Model Publication No.59-47127 JP 2001-107330 A JP 2004-176856 A

  The present invention has been developed in view of the problems of the conventional torque limiter, and it is an object of the present invention to provide an axial force-derived torque limiter that can accurately control the axial force itself to a desired value and has excellent repeatability. Is.

In view of the above problems, the present invention employs the following means.
That is, one aspect of the axial force-induced torque limiter (hereinafter referred to as torque limiter) according to the present invention includes a cage provided with an accommodation hole, and a shaft portion that is accommodated in the accommodation hole and can rotate around the axis. The shaft portion has an insertion shaft portion concentrically connected to one end of the engagement shaft portion having a circular cross section as viewed in the axial direction, and an engagement element separate from the engagement shaft portion. A plurality of locking hole portions provided at equal angles in the circumferential direction on the peripheral wall portion of the cage, and the engagement element is connected to the outer peripheral surface of the engagement shaft portion via a biasing means. And the engagement element is in contact with the engagement inner peripheral surface portion which is one of the opposed portions of the inner peripheral surface of the locking hole portion as viewed in the axial direction. It is possible to contact. Further, the insertion shaft portion is loosely inserted into an insertion hole provided in a central portion of a support ring member having a circular ring shape separate from the shaft portion, and the engagement portion of the outer peripheral portion of the support ring member is inserted. A support portion that can be point-contacted with the engagement element is provided on the opposite side of the coupling element, and the receiving part integrally provided at the distal end of the insertion shaft portion and the support ring member are opposed to each other. A thrust bearing is interposed between the side surfaces, and the receiving portion can rotate relative to the support ring member around the axis of the shaft portion. The shaft portion is pulled in the axial direction or compressed in the axial direction to increase the axial force of the shaft portion, whereby the engaging element is supported by the support ring member. As the axial force increases, the external force that the engaging element receives from the support ring member increases, and the external force that the engaging element receives from the outer peripheral surface of the engaging shaft portion decreases. In a state where the external force received by the engagement element from the outer peripheral surface is reduced to a desired external force value or in a state where the external force becomes zero and the axial force reaches a desired cutoff axial force value, the shaft portion It can rotate relative to the support ring member around the axis via a bearing, and the axial force can be held by holding means.

  Another aspect of the torque limiter according to the present invention includes a cage provided with an accommodation hole, and a shaft portion that is accommodated in the accommodation hole and can rotate about an axis, and the shaft portion has a circular cross section. An insertion shaft portion is concentrically connected to both ends of the engagement shaft portion as viewed in the axial direction, and an engagement element separate from the engagement shaft portion is provided on the peripheral wall portion of the retainer in the circumferential direction. Are fitted into each of a plurality of locking holes provided at equal angles, and the engaging member is elastically pressed against the outer peripheral surface of the engaging shaft portion via the biasing means. In addition, the engaging element can be brought into contact with the engaging inner peripheral surface portion which is one of the facing portions of the inner peripheral surface of the locking hole portion as viewed in the axial direction. Each of the insertion shaft portions is loosely inserted into an insertion hole provided in a center portion of a support ring member having a circular ring shape separate from the shaft portion, and the outer peripheral portion of the support ring member On the opposite side of the engagement element, a support part capable of making point contact with the engagement element is provided, and the receiving part integrally provided at the distal end of the insertion shaft part and the support ring member are opposed to each other. A thrust bearing is interposed between the side surfaces, and the receiving portion can rotate relative to the support ring member around the axis of the shaft portion. And, the shaft is pulled in the axial direction or compressed in the axial direction to increase the axial force of the shaft member, so that the engagement element is supported by the support ring member, As the axial force increases, the external force that the engaging element receives from the support ring member increases, and the external force that the engaging element receives from the outer peripheral surface of the engaging shaft portion decreases. In a state where the external force received by the engagement element from the outer peripheral surface is reduced to a desired external force value or in a state where the external force becomes zero and the axial force reaches a desired cutoff axial force value, the shaft portion It can rotate relative to the support ring member around the axis via a bearing, and the axial force can be held by holding means.

  In each of the torque limiters, it is preferable that the support portion is formed as a linear inclined support surface.

The present invention has the following excellent effects.
(1) When using the torque limiter according to the present invention, as the axial force increases, the external force received by the engagement element from the support ring member increases, and the external force received by the engagement element from the outer peripheral surface of the engagement shaft portion Decrease. In other words, the limit transmission torque (maximum torque that can be transmitted) can be reduced as the axial force increases.

  Therefore, unlike the conventional torque limiter where the limit transmission torque is constant regardless of the axial force, the torque transmission is interrupted with an axial force smaller than the desired axial force. The conventional problems such as the case where torque transmission cannot be interrupted even when the axial force reaches a large value can be solved. Further, the loss torque of the support portion of the screw shaft as in the conventional friction surface slip type torque limiter can be reduced, and the influence of torque caused by the moment of inertia of the rotating portion during acceleration motion can be greatly reduced.

  Therefore, according to the present invention, the axial force itself can be accurately controlled to a desired value, and an axial force-derived torque limiter having excellent repetition characteristics can be provided.

(2) In the torque limiter according to the present invention, the desired breaking axial force value is set in consideration of the axial force required for the shaft portion, and the desired breaking axial force value is set. As main elements for the above, the number of the engagement members elastically pressed against the outer peripheral surface of the engagement shaft portion, the magnitude of the urging force of the urging means, and the engagement member with respect to the support portion of the support ring member There is a magnitude of the angle between the direction of the force at the contact point, that is, the normal direction, and the axis.

  Therefore, the set cutoff axial force value can be easily and reliably set by appropriately setting these elements. For example, with regard to the angle, the smaller the angle, the smaller the radial component of the external force received from the support portion, so that the decrease in the external force received by the engagement element from the outer peripheral surface can be further reduced. The torque can be set larger, and therefore the desired cutoff axial force value can be set larger. Conversely, as the angle increases, the radial component of the external force received from the support portion increases, so that the reduction of the external force received by the engagement element from the outer peripheral surface can be set larger, and the limit transmission torque becomes smaller. Therefore, the desired cutoff axial force value can be set smaller. Thus, by changing the angle, the desired cutoff axial force value can be easily and reliably set in consideration of the axial force required for the shaft member.

(3) The torque limiter according to the present invention is provided with insertion shaft portions at both ends when viewed in the axial direction of the engagement shaft portion, and each insertion shaft portion is loosely inserted into an insertion hole provided at the center portion of the support ring member. When configured as being inserted, the torque limiter can be used both when pulling the load and when pushing the load. Also, there is an advantage that the axial force when pulling the load and the axial force when pushing the load can be individually set, and the control of the axial force can be diversified.

(4) When the support portion is configured as a linear inclined support surface, the setting of the angle becomes easy, and therefore the manufacture of the support ring member can be facilitated.

It is sectional drawing which shows the torque limiter which concerns on this invention. FIG. It is a disassembled perspective view which shows the torque limiter which concerns on this invention. It is explanatory drawing explaining the state of the external force which an engagement child receives. It is explanatory drawing explaining the angle condition based on the relationship with the inclination support surface which is one of the elements which set a desired interruption | blocking axial force value. It is sectional drawing which shows the other Example of the torque limiter which concerns on this invention. FIG. It is a disassembled perspective view explaining the torque limiter. It is explanatory drawing explaining the action state of the external force in the torque limiter. It is explanatory drawing explaining the angle condition based on the relationship with the inclination support surface which is one of the elements which set a desired interruption | blocking axial force value. It is sectional drawing which shows the torque limiter comprised so that utilization of both the case where a load was pulled and the case where a load was pushed is carried out. It is a partial cross section front view which illustrates the holding means. It is a partial cross section front view which shows the other usage condition of the torque limiter comprised so that it can utilize both when the load is pulled and the load is pushed. It is the perspective view and sectional drawing which show the other aspect of an engaging element. It is the disassembled perspective view and sectional drawing which show the other aspect of the cylindrical ring-shaped spring member which comprises a biasing means. It is a perspective view which shows the other aspect of a ring-shaped spring member. It is a partial cross section front view which shows the other aspect of the biasing means using a compression spring. It is sectional drawing which shows the inclination support surface comprised as a curved surface. It is explanatory drawing which shows the aspect which provided the load distribution circumferential groove in the outer peripheral surface of the engaging shaft part with the action state of external force. It is explanatory drawing which shows the aspect which provided the load dispersion | distribution recessed part in the outer peripheral surface of an engaging shaft part with the action state of external force. It is explanatory drawing explaining the change of the external force in that case. It is explanatory drawing which shows the case where a load distribution recessed part is provided in the load distribution peripheral groove together. Sectional view and perspective view showing a case where a load distribution circumferential groove is provided on the outer peripheral surface of the engagement shaft portion, a load distribution linear groove is provided on the inclined support surface, and a load distribution peripheral groove is provided on the inner peripheral surface of the ring-shaped spring member FIG. It is a fragmentary perspective view which shows the case where a load distribution recessed part is provided in the internal peripheral surface of a ring-shaped spring member. It is sectional drawing which shows the case where a load dispersion | distribution circumferential groove is comprised in the cross-section V shape. It is explanatory drawing explaining the conventional torque limiter.

  1-3, the torque limiter 1 according to the present invention is applied to a device that pulls a load, for example, a linear motion device 2 as a tensioning device 2a that tensions by pulling a belt, a chain, a wire, or the like. A cage 4 provided with an accommodation hole 3 made of a hole, and a shaft member 6 provided with a shaft portion 5 accommodated in the accommodation hole 3 and capable of rotating around an axis.

  In the present embodiment, as shown in FIG. 3, the retainer 4 is formed on one end surface 13 of the substrate portion 12 in which upper and lower ends 7 and 9 are formed flat and left and right side surfaces 10 and 11 are formed in arcuate surfaces. A cylindrical portion 16 protrudes through a step 15, and the circular accommodating hole 3 having the same diameter is provided concentrically with the cylindrical portion 16 across the cylindrical portion 16 and the substrate portion 12. It has been. A connecting screw shaft 19 projects from the other end surface 17 of the substrate portion 12 concentrically with the cylindrical portion 16. The connecting screw shaft 19 is screwed into a screw hole 21 provided at an end of the tensioning device 2a connected to a load, so that the retainer 4 is connected to the tensioning device 2a. .

  As shown in FIGS. 2 to 3, the peripheral wall portion 22 of the cylindrical portion 16 has four locking hole portions 23, 23, 23, 23 at an angle of 90 degrees in the circumferential direction. Each of the locking holes 23 has a spherical engagement element (in this embodiment, a spherical body) having a diameter substantially equal to the inner diameter of the locking hole 23. The engagement element 25) 25 is fitted.

  Further, as shown in FIGS. 2 to 3, a fitting circumferential groove 29 is provided near the accommodation hole open end 27 of the outer circumferential surface 26 of the cylindrical portion 16. A snap ring 33 that supports the outer surface 32 of the stopper ring 31 having a circular insertion hole 30 into which the cylindrical portion 16 is inserted in a substantially close state is fitted from the outside. A cylindrical ring made of a metal material having a high spring property for pressing the engaging element 25 in the radial direction of the cylindrical portion 16 between the step 15 and the inner side surface 35 of the stopper ring 31. An urging means 36 as a ring-shaped spring member 36 a is mounted so as to surround the peripheral wall portion 22, and the stopper ring 31 prevents the ring-shaped spring member 36 a from dropping from the peripheral wall portion 22. .

  The shaft member 6 is formed in a round shaft shape, and a screw shaft extending in the direction of the axis L of the shaft portion 5 on the outer surface 37 of the shaft portion 5 housed in the housing hole 3 of the retainer 4. The part 39 is continuously provided. As shown in FIGS. 1 and 3, the screw shaft portion 39 is inserted into a circular insertion hole 43 provided on a bearing standing wall 42 erected on a base 41 at a tip portion 40 thereof. A nut 46 a constituting the holding means 46 is screwed onto the screw shaft portion 45 protruding from the bearing standing wall 42.

  As shown in FIGS. 2 to 3, the shaft portion 5 has an inner surface (a surface on the bottom surface 49 side of the housing hole 3) of a large-diameter disk-shaped end shaft portion 47 existing on the housing hole open end 27 side. ), An engaging shaft portion 51 having a circular cross section is concentrically connected via an inclined step 50, and the axis L of the shaft portion 5 is connected to the distal end surface (inner surface) 52 of the engaging shaft portion 51. A cylindrical insertion shaft 55 having a smaller diameter is connected concentrically through a step surface 53 that forms a right angle with the step surface 53.

  As shown in FIG. 2, the engagement elements 25, 25, 25, 25 fitted in the locking holes 23, 23, 23, 23 are formed on the inner circumference of the ring-shaped spring member 36 a having a cylindrical shape. It is configured to be elastically pressed by the surface 56 and elastically pressed to the outer peripheral surface 57 of the engagement shaft portion 51. The engagement element 25 is an engagement inner peripheral surface portion (in the present embodiment, the inner peripheral surface portion of the engagement hole portion 23, which is one of the facing portions viewed in the direction of the axis L). Due to the engagement with the engagement inner peripheral surface portion 60 as a portion on the open end side of the accommodation hole 3, the movement of the shaft portion 5 is prevented in the direction of coming out of the accommodation hole 3.

  Further, the insertion shaft portion 55 is loosely inserted into an insertion hole 62 provided in the center portion of a support ring member 61 that has a circular ring shape that is separate from the shaft member 6. On the opposite side of the outer peripheral portion 63 of the support ring member 61 to the engagement element 25, a support portion serving as an inclined support surface 66a that can support the engagement element 25 by making point contact with the spherical surface 65 of the engagement element 25. 66 is provided so as to be inclined outward in the circumferential direction toward the distal end direction of the shaft portion 5. In the present embodiment, the inclined support surface 66a is formed as a linear inclined surface, and the inclination angle θ1 with respect to the axis L direction is set to 45 degrees.

  In addition, a thrust bearing (in this embodiment, a thrust needle bearing) 71 is interposed between the opposing side surfaces 69 and 70 of the receiving portion 67 and the support ring member 61 that are integrally provided at the distal end of the insertion shaft portion 55. The receiving portion 67 can be rotated relative to the support ring member 61 in the circumferential direction via the thrust bearing 71. As shown in FIG. 2, the receiving portion 67 is configured with a circular ring member 72, and a screw shaft portion 73 that forms the front side portion of the insertion shaft portion 55 is formed on the circular ring member 72. Screwed into the screw hole 75. The circular ring member 72 is fixed to the insertion shaft portion 55 by tightening a fixing screw 77 that is screwed to the outer peripheral surface portion of the circular ring member 72 and presses the outer peripheral surface 76 of the screw shaft portion 73. Thus, the receiving portion 67 is configured.

  As the nut 46a is tightened in FIG. 1, the shaft member 6 is pulled in the axial direction to increase the axial force. Further, as described above, the engagement element 25 is supported by the inclined support surface 66a of the support ring member 61 in a point contact state. For this reason, as the axial force of the shaft member 6 increases by tightening the nut 46a, the external force that the engaging element 25 receives from the inclined support surface 66a increases. The external force received from the outer peripheral surface 57 of the engagement shaft portion 51 is reduced. A state where the external force received by the engagement element 25 from the outer peripheral surface 57 of the engagement shaft portion 51 is reduced to a desired external force value or a state where the external force becomes zero, that is, the axial force is a desired cutoff axial force value. In this state, the shaft member 6 can rotate around the axis L with respect to the support ring member 61 via the thrust bearing 71. The axial force at this time is held by the holding means 46 including the nut 46a.

  Next, the operation of the torque limiter 1 having such a configuration will be described in more detail. Considering the case where the linear motion device (tension device 2a) 2 is required to have a tension force required to tension the belt or the like, the necessary tension force is applied to the linear motion device 2 that leads to a load. This is ensured by increasing the axial force of the shaft portion 5 of the connected torque limiter 1 to a desired cutoff axial force value.

  For this purpose, first, the four engaging elements 25, 25, 25, 25 elastically move the outer peripheral surface 57 of the engaging shaft portion 51 so that the axial force of the shaft member 6 can take a desired cutoff axial force value. The urging force by the ring-shaped spring member 36a is set as required so that the frictional force generated by pressing to the desired value. Due to the frictional force, a limit transmission torque (maximum torque that can be transmitted) is generated between the engagement element 25 and the outer peripheral surface 57.

  In this state, the tension device 2a tightens the nut 46a in order to bring the belt or the like into a required tension state. By tightening the nut 46a, the shaft member 6 moves in the right direction F in FIG. 1, and the axial force of the shaft member 6 increases. The state of the external force received by the engagement element 25 during this period will be described based on FIGS. 4 (A), 4 (B), and 4 (C). Here, the external force received by the engagement element 25 from the ring-shaped spring member 36a (external force received in the radial direction of the engagement element) is the first external force F1, and the engagement element 25 is the outer peripheral surface 57 of the engagement shaft portion 51. The external force received from (the external force received in the radial direction of the engagement element) is the second external force F2, and the external force received by the engagement element 25 from the engagement inner peripheral surface portion 60 of the locking hole 23 (in the radial direction of the engagement element). The external force received) is the third external force F3, and the external force received by the engagement element 25 from the inclined support surface 66a of the support ring member 61 (the external force received in the radial direction of the engagement element) is the fourth external force F4.

  FIG. 4A shows an external force acting state when the axial force of the shaft member 6 is zero. The external force received by the engaging element 25 is the first external force F1 received from the ring-shaped spring member 36a. Only the second external force F2 received from the outer peripheral surface 57 of the engagement shaft portion 51, and the limit transmission torque at this time is the maximum.

  FIG. 4B shows an external force acting state when the axial force is smaller than the desired cutoff axial force value. The external force received by the engagement element 25 is the first received by the ring-shaped spring member 36a. An external force F1, a second external force F2 received from the outer peripheral surface 57 of the engagement shaft portion 51, a third external force F3 received from the engagement inner peripheral surface portion 60, and a fourth external force F4 received from the inclined support surface 66a. It is. As the axial force increases, the fourth external force F4 received by the engaging element 25 from the inclined support surface 66a increases, and the second external force F2 received from the outer peripheral surface 57 of the engaging shaft portion 51 increases. Decrease. As described above, as the second external force F2 decreases due to the increase in the axial force, the limit transmission torque decreases, and the torque transmission surplus force (in accordance with the limit transmission torque and the axial force of the torque limiter 1). The difference with the transmitted torque) decreases.

  FIG. 4C shows an external force acting state when the axial force reaches the desired cutoff axial force value. The external force received by the engagement element 25 is the first force received from the ring-shaped spring member 36a. An external force F1, a second external force F2 received from the outer peripheral surface 57 of the engagement shaft portion 51, a third external force F3 received from the engagement inner peripheral surface portion 60, and a fourth external force F4 received from the inclined support surface 66a. However, the fourth external force F4 received by the engaging element 25 from the inclined support surface 66a is increased, and the second external force F2 received from the outer peripheral surface 57 is reduced to a desired external force value. It is in the zero state. In this state, the torque transmission reserve is zero. In this state, the engagement elements 25, 25, 25, 25 and the support ring member 61 are integrated. As described above, the insertion shaft portion 55 is loosely inserted into the insertion hole 62 provided in the center portion of the support ring member 61 having a circular ring shape separate from the shaft member 6. In a state where the ring member 61 is integrated with the engagement elements 25, 25, 25, 25, the insertion shaft portion 55 is not in contact with the inner peripheral surface of the insertion hole 62.

  2, the thrust bearing 71 is interposed between the opposing side surfaces 69 and 70 of the receiving portion 67 and the support ring member 61 that are integrally provided at the distal end of the insertion shaft portion 55. Yes. For this reason, in this state, the receiving portion 67 rotates around the axis L with respect to the support ring member 61 via the thrust bearing 71. That is, the second external force F2 received by the engagement element 25 is in a state of being reduced to a desired external force value or in a state of zero, so that the nut 46a is fastened to the screw shaft portion 39 as soon as possible. Therefore, the nut 46a and the screw shaft portion 39 rotate together. This rotation can be detected visually or with a sensor.

As a result, a state in which the belt or the like is tensioned through the tensioning device 2a is obtained. Since the set axial force of the shaft portion 5 is held by the holding means 46 as the nut 46a, the tension state of the belt or the like is held as it is.
The fourth external force F4 is an external force that the engaging element 25 receives from the inclined support surface 66a, and is orthogonal to the inclined support surface 66a. The fourth external force F4 is divided into an axial direction component (component in the axis L direction of the shaft member 6) and a radial direction component (component in a direction orthogonal to the axis L of the shaft member 6). In the present embodiment, four of the engagement elements 25 that are in a point-like contact state with the inclined support surface 66a are arranged at an equal angle (90 degrees in the present embodiment) in the circumferential direction of the peripheral wall portion 22. Therefore, the radial direction component of the fourth external force F4 received by each engagement element 25 is canceled. Therefore, the support ring member 61 cannot move in the radial direction. Therefore, the support ring member 61 does not come into contact with the insertion shaft portion 55. The axial direction component of the fourth external force F4 received by each engagement element 25 is loaded on the thrust bearing 71, and thus the axial direction component affects the transmission torque between the shaft portion 5 and the engagement element 25. Don't give.

  When the torque limiter 1 having such a configuration is used, as described above, the external force that the engaging element 25 receives from the outer peripheral surface 57 of the engaging shaft portion 51 decreases as the axial force of the shaft portion 5 increases. That is, unlike the conventional torque limiter in which the limit transmission torque is constant regardless of the axial force of the shaft member, the limit transmission torque is reduced. Therefore, it can be said that the torque transmission surplus force of the torque limiter 1 having the above-described configuration is larger than that of the conventional torque limiter in a state where it is smaller than the cutoff axial force value. Therefore, the torque limiter 1 can accurately control the axial force itself to a desired value and has excellent repetition characteristics.

  The main elements for setting the cutoff axial force value are the number of the engagement elements 25 that are elastically pressed against the outer peripheral surface 57 of the engagement shaft part 51, and the engagement elements 25 by the urging means 36. There is a pressing force and an inclination angle of the inclined support surface 66a.

  The desired cutoff axial force value is set in consideration of a desired axial force required for the shaft portion 5, and the setting means will be described here. The main elements for setting the desired cutoff axial force value are the number of the engagement elements 25 that are elastically pressed against the outer peripheral surface 57 of the engagement shaft portion 51 and the ring shape that is a kind of urging means. The magnitude of the pressing force of the engaging element 25 via the spring member 36a and a straight line connecting the contact point 79 of the engaging element 25 with the inclined support surface 66a and the center 64 of the engaging element 25 shown in FIG. The angle θ2 formed with the axis L is large or small. In this embodiment, the inclination angle θ1 (FIG. 3) of the inclined support surface 66a with respect to the axis L is large or small.

  More specifically, the breaking axial force value can be increased as the number of the engagement elements 25 is increased. This number is also related to the diameter of the engagement shaft portion 51. The larger the diameter, the larger the number of engagement elements 25 provided.

  Further, the greater the biasing force of the ring-shaped spring member 36a, the larger the second external force F2 that the engaging element 25 receives from the outer peripheral surface 57 can be set. As a result, the limit transmission torque can be set larger, and the desired cutoff axial force value can be set larger. Conversely, the second external force F2 can be set smaller as the biasing force is smaller. Thus, the limit transmission torque can be set smaller, and the desired cutoff axial force value can be set smaller.

  Further, since the radial component of the external force F4 received from the inclined support surface 66a decreases as the inclination angle θ1 of the inclined support surface 66a increases, the decrease in the external force received from the outer peripheral surface 57 by the engagement element 25 becomes smaller. The limit transmission torque can be set larger. Therefore, the desired cutoff axial force value can be set larger. Conversely, as the inclination angle θ1 is smaller, the radial direction component of the external force F4 received from the inclined support surface 66a is larger, so that the reduction of the external force received by the engagement element 25 from the outer peripheral surface 57 can be set larger. The limit transmission torque can be set smaller. Therefore, the desired cutoff axial force value can be set smaller.

  6 to 8 show another embodiment of the torque limiter 1 according to the present invention, and a linear motion device as a pressing device 2b that presses a load (for example, a pressing device 2b that tensions a belt, chain, wire, or the like). 2), for example, a retainer 4 provided with a receiving hole 3 formed of a circular hole, and a shaft member provided with a shaft portion 5 that is received in the receiving hole 3 and can rotate around the axis L 6 is provided.

  7 to 8, in the present embodiment, the retainer 4 has one end surface 13 of a substrate portion 12 in which upper and lower ends 7, 9 are formed flat and left and right side surfaces 10, 11 are formed in arcuate surfaces. Further, a cylindrical portion 16 is provided so as to protrude through a step 15, and the circular accommodating hole 3 having the same diameter and concentric with the cylindrical portion 16 extends over the cylindrical portion 16 and the substrate portion 12. Is provided. A connecting screw shaft 19 projects from the other end surface 17 of the substrate portion 12 concentrically with the cylindrical portion 16. The connecting screw shaft 19 is screwed into a screw hole 21 provided at an end of the pressing device 2b connected to a load, so that the retainer 4 is connected to the pressing device 2b. .

  7-8, the peripheral wall portion 22 of the cylindrical portion 16 has four locking hole portions 23, 23, 23, 23 at an angle of 90 degrees in the circumferential direction, respectively. Each of the locking holes 23 has a spherical engagement element (in this embodiment, a spherical body) having a diameter substantially equal to the inner diameter of the locking hole 23. The engaging element 25) is adapted to be fitted.

  Further, as shown in FIGS. 7 to 8, a fitting circumferential groove 29 is provided near the accommodation hole open end 27 of the outer circumferential surface 26 of the cylindrical portion 16. A snap ring 33 that supports the outer surface 32 of the stopper ring 31 having a circular insertion hole 30 into which the cylindrical portion 16 is inserted in a substantially close state is fitted from the outside. A cylindrical ring made of a metal material having a high spring property for pressing the engaging element 25 in the radial direction of the cylindrical portion 16 between the step 15 and the inner side surface 35 of the stopper ring 31. An urging means 36 as a ring-shaped spring member 36 a is mounted so as to surround the peripheral wall portion 22, and the stopper ring 31 prevents the ring-shaped spring member 36 a from dropping from the peripheral wall portion 22. .

  The shaft member 6 is formed in a round shaft shape, and a screw shaft extending in the direction of the axis L of the shaft portion 5 on the outer surface 37 of the shaft portion 5 housed in the housing hole 3 of the retainer 4. The part 39 is continuously provided. As shown in FIGS. 6 and 8, the screw shaft portion 39 is inserted into a circular insertion hole 43 provided on a bearing standing wall 42 standing on a base 41 at a tip portion 40 thereof, A nut 46 b constituting the holding means 46 is screwed into a screw shaft portion 81 existing inside the bearing standing wall 42.

  As shown in FIGS. 7 to 8, the shaft portion 5 is a disc on the inner side surface (the surface on the bottom surface 82 side of the receiving hole 3) of the engagement shaft portion 51 having a circular cross section via an inclined step 83. And a stepped surface that is perpendicular to the axis L of the shaft portion 5 on the outer surface of the engagement shaft portion 51 (the surface on the receiving hole open end 27 side). A smaller-diameter insertion shaft portion 55 is concentrically connected via 86. A disc-shaped receiving portion 67 is provided concentrically and integrally on the outer end of the insertion shaft portion 55, and an inner side surface 87 of the receiving portion 67 is formed as a surface orthogonal to the axis L.

  In this embodiment, as shown in FIGS. 7 to 8, the receiving portion 67 includes a disc-like portion 90 provided concentrically at the end of the insertion shaft portion 55, and the disc-like portion 90. A screw hole 92 that opens at the inner surface 91 of the disk-shaped portion 90 is provided along the axis L of the disk. Then, a screw shaft 93 connected to the outer end of the insertion shaft portion 55 is screwed into the screw hole portion 92. In the screwed state, the screw shaft 93 is screwed on the outer peripheral surface of the disk-shaped portion 90, and By tightening a fixing screw 96 that presses the outer peripheral surface 95 of the screw shaft 93, the disk-shaped portion 90 is fixed to the insertion shaft portion 55, so that a disk is attached to the outer end of the engagement shaft portion 51. The shape receiving part 67 is configured to be provided concentrically and integrally.

  And as shown in FIG. 7, the said engaging elements 25, 25, 25, 25 currently fitted by the said locking hole parts 23, 23, 23, 23 are the said through the said ring-shaped spring members 36a. The outer peripheral surface 57 of the engagement shaft portion 51 is elastically pressed. The engagement element 25 is an engagement inner peripheral surface portion (in the present embodiment, the housing) that is one of the opposing portions of the inner peripheral surface 59 of the locking hole portion 23 as viewed in the direction of the axis L. By engagement with the engagement inner peripheral surface portion 60 as a portion of the hole 3 on the bottom surface 82 side, the movement of the shaft portion 5 in the direction of moving toward the bottom surface 82 is prevented.

  Further, the insertion shaft portion 55 is loosely inserted into an insertion hole 62 provided in the center portion of a support ring member 61 that has a circular ring shape that is separate from the shaft member 6. On the opposite side of the outer peripheral portion 63 of the support ring member 61 to the engagement element 25, an inclined support surface 66a capable of supporting the engagement element 25 by making point contact with the spherical surface of the engagement element 25 is provided on the shaft portion. 5 is provided so as to incline outward in the circumferential direction toward the tip direction. In the present embodiment, the inclined support surface 66a is formed as a linear inclined surface, and the inclination angle θ1 with respect to the axis L direction is set to 45 degrees. A thrust bearing (in this embodiment, a thrust needle bearing) 71 is interposed between side surfaces 69 and 70 facing the receiving portion 67 and the support ring member 61 that are integrally provided at the distal end of the insertion shaft portion 55. The receiving portion 67 can rotate relative to the support ring member 61 in the circumferential direction.

  The loose insertion of the insertion shaft portion 55 and the intervention of the thrust bearing 71 are performed before the screw shaft 93 is screwed into the screw hole portion 92.

  However, when the torque limiter 1 having such a configuration is used, the shaft member 6 is compressed in the direction of the axis L by tightening the nut 46b, and the axial force of the shaft member 6 increases, so that the engagement element 25 is The support ring member 61 is supported by the inclined support surface 66a. In the same manner as described in the first embodiment, as the axial force increases, the fourth external force F4 received by the engaging element 25 from the inclined support surface 66a increases, and the engaging shaft portion The second external force F2 received from the outer peripheral surface 57 of 51 decreases. As described above, as the second external force F2 decreases due to the increase in the axial force, the limit transmission torque decreases, and the torque transmission surplus force (in accordance with the limit transmission torque and the axial force of the torque limiter 1). The difference with the transmitted torque) decreases.

  FIG. 9 shows an external force acting state when the axial force reaches the desired cutoff axial force value. The external force received by the engagement element 25 is the first external force F1 received from the ring-shaped spring member 36a. The second external force F2 received from the outer peripheral surface 57 of the engagement shaft portion 51, the third external force F3 received from the engagement inner peripheral surface portion 60, and the fourth external force F4 received from the inclined support surface 66a. The fourth external force F4 received by the engaging element 25 from the inclined support surface 66a is increased, and the second external force F2 received from the outer peripheral surface 57 is reduced to a desired external force value or is in a zero state. It is in. In this state, the torque transmission reserve is zero. In this state, the engagement elements 25, 25, 25, 25 and the support ring member 61 are integrated. As described above, the insertion shaft portion 55 is loosely inserted into the insertion hole 62 provided in the center portion of the support ring member 61 having a circular ring shape separate from the shaft member 6. In a state where the ring member 61 is integrated with the engagement elements 25, 25, 25, 25, the insertion shaft portion 55 is not in contact with the inner peripheral surface of the insertion hole 62.

  The thrust bearing 71 is interposed between the opposing side surfaces 69 and 70 of the receiving portion 67 and the support ring member 61 that are integrally provided at the distal end of the insertion shaft portion 55. For this reason, in this state, the receiving portion 67 rotates around the axis L with respect to the support ring member 61 via the thrust bearing 71. That is, since the second external force F2 received by the engagement element 25 is in a state of being reduced to a desired external force value or is in a zero state, the nut 46b is fastened to the screw shaft portion 81 as soon as possible. Thus, the nut 46b rotates integrally with the screw shaft portion 81. This rotation can be detected visually or with a sensor.

  As a result, a state in which the belt or the like is tensioned through the pressing device 2b is obtained. And since the desired axial force of the said shaft member 6 is hold | maintained by the holding means 46 as the nut 46b, the tension | tensile_strength state of a belt etc. will be hold | maintained as it is.

  The fourth external force F4 is an external force that the engaging element 25 receives from the inclined support surface 66a, and is orthogonal to the inclined support surface 66a. The fourth external force F4 is divided into an axial direction component (component in the axis L direction of the shaft member 6) and a radial direction component (component in a direction orthogonal to the axis L of the shaft member 6). In the present embodiment, four of the engagement elements 25 that are in a point-like contact state with the inclined support surface 66a are arranged at an equal angle (90 degrees in the present embodiment) in the circumferential direction of the peripheral wall portion 22. Therefore, the radial direction component of the fourth external force F4 received by each engagement element 25 is canceled. Therefore, the support ring member 61 cannot move in the radial direction. Therefore, the support ring member 61 does not come into contact with the insertion shaft portion 55. The axial direction component of the fourth external force F4 received by each engagement element 25 is loaded on the thrust bearing 71, and thus the axial direction component affects the transmission torque between the shaft portion 5 and the engagement element 25. Don't give.

  When the torque limiter 1 having such a configuration is used, as described above, the external force that the engaging element 25 receives from the outer peripheral surface 57 of the engaging shaft portion 51 decreases as the axial force of the shaft member 6 increases. That is, unlike the conventional torque limiter in which the limit transmission torque is constant regardless of the axial force of the shaft member, the limit transmission torque is reduced. Therefore, it can be said that the torque transmission surplus force of the torque limiter 1 having the above-described configuration is larger than that of the conventional torque limiter in a state where it is smaller than the cutoff axial force value. Therefore, the torque limiter 1 can accurately control the axial force itself to a desired value and has excellent repetition characteristics.

  Then, in a state where the second external force F2 is reduced to a desired external force value or in a state where the second external force F2 is zero and the axial force reaches a desired cutoff axial force value, the shaft portion 5 is It can rotate around the axis L of the shaft member 6 with respect to the support ring member 61 via a thrust bearing 71. The axial force at this time is held by holding means 46 as the nut 46b.

  Note that the desired cutoff axial force value is the number of the engagement elements 25 that are elastically pressed against the outer peripheral surface 57 of the engagement shaft portion 51 and the ring-shaped spring that is a kind of urging means. It can be set by the magnitude of the pressing force of the engaging element 25 through the member 36a. Further, as shown in FIG. 10, the angle θ2 formed by the straight line connecting the contact point 79 of the engagement element 25 with the inclined support surface 66a and the center 64 of the engagement element 25 with the axis L can be set. In the present embodiment, the inclination angle θ1 with respect to the axis L of the inclined support surface 66a can be set to be large or small.

  FIGS. 11 to 12 show another embodiment of the torque limiter 1 according to the present invention. When the load is pulled (for example, applied to the linear motion device 2 as the tensioning device 2a), the load is reduced. It is configured so that it can be used for both pressing (for example, when applied to the linear motion device 2 as the pressing device 2b), and is configured to have the two functions in the first embodiment and the second embodiment. Yes.

  More specifically, the torque limiter 1 is connected to a linear motion device 2 that is connected to a load and is provided with a retainer 4 provided with an accommodation hole 3 made of, for example, a circular hole, and accommodated in the accommodation hole 3 and is axial The shaft portion 5 is capable of rotating around L, and the shaft portion 5 is concentrically connected to the left and right ends of the engagement shaft portion 51 having a circular cross section when viewed in the direction of the axis L. It is installed. The insertion shaft portions 55 and 55 are loosely inserted into insertion holes 62 and 62 provided at the center of the support ring members 61 and 61 having a circular ring shape separate from the shaft portion 5.

  Configuration of the cage 4, Configuration of the engagement element 25, Configuration of attachment of the engagement element 25 to the peripheral wall portion 22 of the cage 4, Configuration of the urging means 36, Configuration of the support ring member 61, and the receiving portion Since the configuration of 67 is the same as that in the first and second embodiments, the same components are denoted by the same reference numerals as those described above, and the detailed description thereof is omitted.

  When the torque limiter 1 is configured in this way, as shown in FIG. 12A, as the nut 46a is tightened, the shaft member 6 is pulled in the direction of the axis L so that the axial force increases. Has been made. As described above, the engaging element 25 is supported in a point-contact state by the inclined support surface 66a of the left support ring member 61a. On the other hand, as shown in FIG. 12B, as the nut 46b is tightened, the shaft member 6 is compressed in the direction of the axis L, and the axial force is increased. As described above, the engagement element 25 is supported in the point-like contact state by the inclined support surface 66a of the right support ring member 61b.

  Therefore, as described in detail in the first and second embodiments, the shaft member 6 is pulled in the axis L direction or compressed in the axis L direction, and the axial force of the shaft portion 5 increases. Thus, the engagement element 25 is supported by one of the support ring members 61, 61, and the engagement element 25 receives from the support ring member 61 as the axial force increases. The fourth external force F4 increases, and the second external force F2 received by the engagement element 25 from the outer peripheral surface 57 of the engagement shaft portion 51 decreases.

  When the torque limiter 1 configured in this way is used, the axial force when pulling the load (when pulling in the direction of the arrow P1 in FIG. 12A) and when pushing the load (in the direction of the arrow P2 in FIG. 12B) There is an advantage that the axial force can be set individually. For example, when pushing, the desired breaking axial force value is increased, and when pulling, the desired breaking axial force value is reduced.

  Note that the desired cutoff axial force value is the number of the engagement elements 25 that are elastically pressed against the outer peripheral surface 57 of the engagement shaft portion 51 and the ring-shaped spring that is a kind of urging means. It can be set by the magnitude of the pressing force of the engagement element 25 through the member 36a, the magnitude of the inclination angle θ1 with respect to the axis L of the inclined support surface 66a, and the like.

  FIG. 13 shows another mode of use of the torque limiter 1 configured to be usable both when pulling a load and when pushing the load. A drive screw shaft 94 is concentrically connected to the shaft portion 5. Has been. In addition, a drive shaft portion 98 is provided on the base plate portion 12 of the cage 4 so as to be concentric with the drive screw shaft 94. When the drive shaft portion 98 is rotated forward and backward by a motor (not shown) via a drive device (not shown), transmission by frictional force generated between the engagement element 25 and the outer peripheral surface 57 of the engagement shaft portion 51 is achieved. The drive screw shaft 94 can be rotated together with the torque limiter 1 by torque.

  A drive nut 104 is screwed onto the drive screw shaft 94, and the drive nut 104 converts a rotational movement of the drive screw shaft 94 into an axial movement of the drive screw shaft 94. is there. In this embodiment, the drive nut 104 is inserted into a lower end portion 118 inside the cylindrical body 114 for accommodating the portion 108 of the drive screw shaft 94 on the front side of the drive nut 104. It is fixed to the portion 118. The drive nut 104 and the cylindrical body 114 are a part of the components of the linear motion device 2.

  The torque limiter 1 can be used both when pulling the load and when pushing the load by the linear motion of the cylindrical body 114 accompanying the forward and reverse rotation of the drive screw shaft 94.

  However, when the drive screw shaft 94 is pulled in the axial direction or compressed in the axial direction and the axial force of the shaft portion 5 is increased, the engagement element 25 is either one of the support ring members 61, 61. On the other hand, it is supported. As the axial force increases, the fourth external force F4 received by the engaging element 25 from the support ring member 61 increases, and the engaging element 25 receives the outer peripheral surface 57 of the engaging shaft portion 51. 2 external force F2 decreases. When the second external force F2 is reduced to the desired external force value or becomes zero, the drive shaft 98 continues to rotate (therefore, the cage 4 and the support ring member 61). Even if the support ring member 61 is in a rotating state, the receiving portion 67 is stopped by the action of the thrust bearing 71. The rotation of the drive screw shaft 94 is stopped. The axial force at this time is held by holding means 46 including the drive nut 104.

  The present invention is by no means limited to those shown in the above-described embodiments, and it goes without saying that various design changes can be made within the scope of the claims. One example is as follows.

(1) One of the elements for setting the cutoff axial force value is the number of the engagement elements 25 that are elastically pressed against the outer peripheral surface 57 of the engagement shaft portion 51 as described above. . The number of the engagement elements 25 may be plural, but the engagement element 25 is not configured as the spherical body 25a as described above, but is a cut in which the opposing portions are parallel as shown in FIG. When configured as the barrel sphere 25b formed as the surfaces 97, 97, the distance between the cut surfaces 97, 97 of the barrel sphere 25b can be made smaller than the diameter of the sphere 25a. Therefore, if the spherical body 25a and the barrel-shaped sphere 25b are compared in terms of the number of mountings when they are arranged on the peripheral wall portion 22 having the same diameter, a larger number of engagement elements 25 can be obtained when the barrel-shaped sphere is mounted. It can be arranged. As long as the axial force increases, the engagement element 25 increases as the external force received from the support ring member 61 increases, and as long as the external force received by the engagement element 25 from the outer peripheral surface 57 of the engagement shaft portion 51 decreases. It can also be configured in a plate shape or the like.

(2) FIG. 15 shows another embodiment of a cylindrical ring-shaped spring member 36a constituting the biasing means 36, and a portion on one end side of the inner peripheral surface 56 is seen in the axial direction. A tapered surface portion 101 having a small diameter from one end 99 to the other end 100 is formed. The tapered surface portion 101 elastically presses the engaging element 25 against the outer peripheral surface 57 of the engaging shaft portion 51. A portion on the other end side of the inner peripheral surface 56 is a female screw inner peripheral surface portion 102.
As shown in FIG. 15, the female thread inner peripheral surface portion 102 is configured to be screwed into a male screw outer peripheral surface portion 103 provided in a portion of the outer peripheral surface of the peripheral wall portion 22 on the accommodation hole open end 27 side. ing. Then, as the screwing amount of the female screw inner peripheral surface portion 102 with respect to the male screw outer peripheral surface portion 103 increases, the elastic force of the engagement element 25 with respect to the outer peripheral surface 57 of the engagement shaft portion 51 by the tapered surface portion 101 is increased. The pressing force can be increased. Thereby, the elastic pressing force of the engagement element 25 against the outer peripheral surface 57 by the ring-shaped spring member 36a can be adjusted as necessary. In this adjustment state, a fixing screw 122 that is screwed into a screw hole 121 provided in the flange 120 provided at the other end portion of the ring-shaped spring member 36a is tightened, and the tip 123 of the fixing screw 122 is moved to the male screw. The screw is held by being pressed on the outer peripheral surface portion 103 of the screw.

(3) The biasing means 36 is constituted by the above-described ring-shaped spring member 36a having a cylindrical shape closed in the circumferential direction, and as shown in FIG. 16, a split groove 105 is provided in the peripheral surface portion. A ring-shaped spring member 36b with a split groove may be used.
In addition, as shown in FIG. 17, the engaging element 25 fitted in the locking hole 23 is pressed as required by a compression spring (coil spring, leaf spring, etc.) 117 fitted in the locking hole 23. It can also be configured as follows. In this case, for example, as shown in FIG. 17, the adjustment screw 107 is screwed into the female screw portion 106 provided in the outer end side portion of the locking hole portion 23, and the screwing amount of the adjustment screw 107 is adjusted. Thus, the elastic pressing force of the engaging element 25 against the outer peripheral surface 57 can be adjusted as necessary. In the case of such a configuration, a collective screwing means is provided so that the adjustment screws 107 screwed into the plurality of locking holes 23 provided in the circumferential direction can be simultaneously screwed by the same amount. You can also.

In addition, the biasing means 36 can be configured using fluid pressure such as air pressure or hydraulic pressure, or can be configured using an electromagnetic valve, and can elastically press the engaging element 25 against the outer peripheral surface 57. In addition, the pressing force can be adjusted. In short, any means can be used as long as it can elastically press the engaging element 25 against the outer peripheral surface 57 and adjust the pressing force by some means.
Further, when the urging means 36 is constituted by the ring-shaped spring member 36a or the ring-shaped spring member 36b with a split groove, these can be constituted by using a composite material of metal and rubber.

(4) The inclined support surface 66a provided on the support ring member 61 may be formed as a curved surface as shown in FIG. 18, for example, in addition to the linear inclined surface described above. is there. Also in this case, the engagement element 25 makes point contact with the inclined support surface 66a formed of a curved surface. Further, the support portion 66 may have a point shape or a line shape in addition to the inclined support surface 66a as long as the support portion 66 can make point contact with the engagement element 25.

(5) The configuration in which the shaft portion 5 is rotated about its axis and the axial force of the shaft portion 5 is held by the holding means 46, as described above, is the normal screw shaft 39 and the normal nuts 46a and 46b. In addition to a combination with the ball screw, a combination of a ball screw and a ball screw nut can also be used. Further, it is composed of a combination of a shaft body and a pair of rollers having an axis inclined with respect to the axis of the shaft body, and is configured so that the shaft body can be rotated by rotating the pair of rollers. In addition, a magnetic screw can be used.

(6) The thrust bearing 71 may be a thrust ball bearing, a thrust roller bearing, or a plate-shaped bearing made of various materials.

(7) FIG. 19 shows that the outer circumferential surface 57 of the engaging shaft portion 51 is provided with a shallow load distribution circumferential groove 110 having a circular arc cross section for fitting the spherical portion 109 of the engaging element 25 in the circumferential direction. Shows the case. The groove depth is set to, for example, about 0.2 to 0.3 mm. In the case of such a configuration, since a larger axial force is required depending on the use condition of the torque limiter, the pressing force by the engagement element 25 against the outer peripheral surface 57 of the engagement shaft portion 51 is increased as described above. Unlike the case of the point-like contact state, the engagement element 25 becomes an arc-like linear contact state in the load distribution circumferential groove 110 and can distribute the load. Therefore, even when the pressing force is increased in order to ensure a large desired breaking axial force value, it is possible to prevent the engagement shaft portion 51 from being damaged due to excessive stress acting on the outer peripheral surface 57. When configured as a circumferential groove in this way, the engagement element 25 can be fitted into the load distribution circumferential groove 110 regardless of the positional relationship of the engagement elements 25 arranged in the circumferential direction of the circumferential wall portion 22. .

  FIG. 19 also shows the action states of the first external force F1, the second external force F2, the third external force F3, and the fourth external force F4 when the load distribution circumferential groove 110 is provided. . In this state, the axial force of the shaft member 6 is increased by tightening the nut 46a and the nut 46b. Further, by tightening the nut 46a and the nut 46b, the external force received by the engagement element 25 from the outer peripheral surface 57 of the engagement shaft portion 51 is reduced, and the axial force of the shaft member 6 reaches a desired cutoff axial force value.

  FIG. 20 shows a case where a spherical shallow load distribution recess 113 is provided on the outer peripheral surface 57 of the engagement shaft portion 51 together with the arrangement of the engagement element 25 for the same purpose. The depth of the load distribution recess 113 is set to about 0.2 to 0.3 mm, for example. When configured in this manner, the engagement element 25 can be in a spherical contact state with the load dispersion recess 113 to disperse the load. FIG. 20 also shows the action states of the first external force F1, the second external force F2, the third external force F3, and the fourth external force F4 when the load distribution recess 113 is provided. FIG. 21A shows a state where the second external force F2 is zero, but the engagement element 25 is housed in the load distribution recess 113. FIG. When the nut 46a and the nut 46b are further tightened in this state, the engagement element 25 is detached from the load distribution recess 113 as shown in FIG. At this time, the engagement element 25 slightly displaces the ring-shaped spring member 36a outward in the radial direction, the engagement element 25 escapes from the load distribution recess 113, and the axial force of the shaft member 6 is a desired cutoff axial force value. Can be reached.

  FIG. 22 shows a case where a shallow spherical load distribution recess 113 is further provided in the groove bottom portion 111 of the load distribution circumferential groove 110 in accordance with the arrangement of the engagement elements 25.

  23 (A) and 23 (B) show a shallow load distribution linear shape that is linear in a circular arc shape along the inclination direction of the inclined support surface 66a in order to protect the inclined support surface 66a by load distribution. The case where the groove | channel 115 was provided is shown.

  23 (A) and 23 (C) show that when the urging means 36 includes the ring-shaped spring member 36a and the ring-shaped spring member 36b with a split groove, the ring is protected in order to protect them by load distribution. A case is shown in which a shallow load distribution circumferential groove 116 having an arcuate cross section into which the engagement element 25 is fitted is provided on the inner peripheral surface 56 of the ring-shaped spring member 36a or the ring-shaped spring member 36b. FIG. 24 shows a case where a spherical shallow load distribution recess 117 is provided on the inner circumferential surface 56 at a required angle in the circumferential direction for the same purpose.

  FIG. 25 shows a load distribution circumferential groove 110 having a V-shaped cross section provided on the outer peripheral surface 57 of the engaging shaft portion 51. Further, the inclined support surface 66a also has a V-shaped cross section. It is possible to provide a load-distributed linear groove exhibiting

(8) The accommodation hole 3 may be configured as a through-hole instead of a bottomed one as shown in FIGS.

DESCRIPTION OF SYMBOLS 1 Torque limiter 2 Linear motion apparatus 2a Tension apparatus 3 Accommodating hole 4 Cage 5 Shaft part 6 Shaft member 12 Substrate part 16 Cylindrical part 22 Peripheral wall part of cylindrical part 23 Locking hole part 25 Engagement element 37 Outer surface of axial part 39 Screw shaft portion 46 Holding means 46a Nut 46b Nut 47 End shaft portion 51 Engagement shaft portion 55 Insertion shaft portion 57 Outer peripheral surface of engagement shaft portion 59 Inner peripheral surface of locking hole 60 Engagement inner peripheral surface portion 61 Support ring Member 62 Insertion hole 66 Support portion 66a Inclined support surface 67 Receiving portion 71 Thrust bearing 110 Load distribution circumferential groove 113 Load distribution recess 117 Load distribution recess

Claims (3)

A cage having a housing hole and a shaft portion that is housed in the housing hole and can rotate around the axis line, the shaft portion of the engagement shaft portion having a circular cross section as viewed in the axial direction. A locking hole in which an insertion shaft portion is concentrically connected to one end, and a plurality of engaging members separate from the engaging shaft portion are provided at equal angles in the circumferential direction of the peripheral wall portion of the cage. And the engagement element is elastically pressed against the outer peripheral surface of the engagement shaft portion via the urging means, and the engagement element is formed in the engagement hole portion. Of the inner peripheral surface of the inner peripheral surface of the engagement inner peripheral surface portion that is any one of the opposing portions seen in the axial direction,
Further, the insertion shaft portion is loosely inserted into an insertion hole provided in a central portion of a support ring member having a circular ring shape separate from the shaft portion, and the engagement portion of the outer peripheral portion of the support ring member is inserted. On the opposite side of the coupling, a support portion that can come into point contact with the engagement element is provided,
In addition, a thrust bearing is interposed between the opposing side surfaces of the receiving portion integrally provided at the tip of the insertion shaft portion and the supporting ring member, and the receiving portion is in contact with the supporting ring member. Relative rotation is possible around the axis of the shaft,
The engagement portion is configured to be supported by the support ring member when the shaft portion is pulled or compressed in the axial direction to increase the axial force of the shaft portion.
As the axial force increases, the external force that the engaging element receives from the support ring member increases, and the external force that the engaging element receives from the outer peripheral surface of the engaging shaft portion decreases.
In a state where the external force received by the engagement element from the outer peripheral surface is reduced to a desired external force value or in a state where the external force becomes zero and the axial force reaches a desired cutoff axial force value, the shaft portion An axial force-induced torque limiter that is capable of rotating relative to the support ring member about an axis via a bearing and capable of holding the axial force by holding means. A cage having a housing hole and a shaft portion that is housed in the housing hole and can rotate around the axis line, the shaft portion of the engagement shaft portion having a circular cross section as viewed in the axial direction. Insertion shafts are concentrically connected to both ends, and a plurality of engaging holes separate from the engagement shafts are provided in the circumferential wall of the retainer at equal angles in the circumferential direction. And the engagement element is elastically pressed against the outer peripheral surface of the engagement shaft portion via the urging means, and the engagement element is formed in the engagement hole portion. Of the inner peripheral surface of the inner peripheral surface of the engagement inner peripheral surface portion that is any one of the opposing portions seen in the axial direction,
Each of the insertion shaft portions is loosely inserted into an insertion hole provided in a center portion of a support ring member having a circular ring shape separate from the shaft portion, and the outer peripheral portion of the support ring member On the opposite side of the engagement element, a support portion that can come into point contact with the engagement element is provided,
In addition, a thrust bearing is interposed between the opposing side surfaces of the receiving portion integrally provided at the tip of the insertion shaft portion and the supporting ring member, and the receiving portion is in contact with the supporting ring member. Relative rotation is possible around the axis of the shaft,
When the shaft portion is pulled in the axial direction or compressed in the axial direction to increase the axial force of the shaft member, the engagement element is supported by the support ring member,
As the axial force increases, the external force that the engaging element receives from the support ring member increases, and the external force that the engaging element receives from the outer peripheral surface of the engaging shaft portion decreases.
In a state where the external force received by the engagement element from the outer peripheral surface is reduced to a desired external force value or in a state where the external force becomes zero and the axial force reaches a desired cutoff axial force value, the shaft portion An axial force-induced torque limiter that is capable of rotating relative to the support ring member about an axis via a bearing and capable of holding the axial force by holding means.   The axial force-induced torque limiter according to claim 1, wherein the support portion is a linear inclined support surface.

Images