JP2018194091A - Bidirectional torque limiter - Google Patents

Abstract

To provide a bidirectional torque limiter having excellent workability in assembling an inner ring member to an outer ring member, and exerting stable performance.SOLUTION: A bidirectional torque limiter 1 includes an inner ring member 10 to which a bidirectional coil spring 70 having one end portion 70a and the other end portion 70b is fixed at an outer peripheral face, and an outer ring member 30 locking both end portions of the bidirectional coil spring 70 in a state of inserting and fixing the inner ring member 10 from an axial direction. An inner face of the outer ring member 30 is provided with engagement recessed portions 35a, 35b permitting insertion of one end portion 70a and the other end portion 70b of the bidirectional coil spring in axially inserting the inner ring member to the outer ring member, and keeping the bidirectional coil spring in an engagement state by butting an end face of one end portion of the bidirectional coil spring and the other end portion to each other, and recessed portions 35a', 35b' positioned in opposition to the engagement recessed portions, including restriction portions 50 for preventing insertion of the bidirectional coil spring, and having the shape substantially same as the engagement recessed portions.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a bidirectional torque limiter that limits load torque associated with rotation transmitted in both directions to a predetermined value or less.

  Generally, a torque limiter cuts off the transmission of torque when a large torque exceeding a certain value is applied in a rotation transmission mechanism. For example, a paper limiter for electronic information equipment such as a printer or a copier is used. It is installed on the roller part of the mechanism. Such a torque limiter includes a contact type that obtains rotational torque by mechanical friction. For example, as disclosed in Patent Document 1, an inner ring member that rotates integrally with a rotation shaft, There is known a coil spring that is tightly fitted on the outer periphery, and an outer ring member (case member) that fixes one end of the coil spring and covers the inner ring member.

  In addition to limiting the load torque associated with the rotation transmitted in one direction, the torque limiter is installed at a part that is rotationally driven in both directions as disclosed in Patent Documents 2 and 3, for example. Are known that limit rotation (limits load torque associated with rotation transmitted in both directions). In this bidirectional torque limiter, both ends of a spring member that is tightly fitted to an inner ring member are bent to form a hook portion (such a spring member is also referred to as a bidirectional coil spring), and the bent hook portion is used as an outer ring. It is made to latch in the notch recess formed in the inner surface of the member.

JP 2014-145380 A Japanese Patent No. 3315603 JP 2000-19597

  In the bidirectional torque limiter described above, the outer ring member and the inner ring member have a cylindrical shape, and a predetermined torque is generated in a state where a bidirectional coil spring is interposed between them (a certain level or more). Both slip when torque is applied). Generally, the outer ring member and the inner ring member are integrally formed by molding a resin, and the inner ring member and the outer ring member each have a central axis in consideration of mold removal and rotational stability during molding. It is preferable that it is formed in a symmetrical shape with respect to the center. In addition, since the bidirectional torque limiter is integrated by incorporating the inner ring member with the bi-directional coil spring fitted into the outer ring member, the assembling workability is good and the performance is stable in the integrated state. It is preferable to be configured so that it can be exhibited.

In this respect, the known bidirectional torque limiter has a structure in which the end of the bidirectional coil spring is bent and the bent portion is locked to a recess formed in the inner periphery of the outer ring member. It is troublesome. Further, as described above, when the outer ring member has a symmetrical shape, a similar recess is formed at the symmetrical position (a position facing 180 °), and the bent portion of the end portion of the bidirectional coil spring is erroneously formed at this portion. The inner ring member may be incorporated into the outer ring member so as to be locked. Even if it is mistakenly assembled in this way, the inner ring member can be integrated with the outer ring member, so there is no problem in appearance, but there may be a problem that the bidirectional coil spring comes off in actual driving.
In addition, it is conceivable to put a mark on the outer ring member so that the inner ring member can be inserted into an appropriate position of the outer ring member. However, since such a mark is difficult to see, erroneous mounting is reliably prevented. It is not possible.

  The present invention has been made based on the above-described problems, and an object of the present invention is to provide a bidirectional torque limiter that has good workability of assembling the inner ring member with respect to the outer ring member and can exhibit stable performance.

  In order to solve the above-described problem, a bidirectional torque limiter according to the present invention includes both one end portion extending linearly and the other end portion extending linearly in a direction opposite to the one end portion. An inner ring member in which a directional coil spring is fixed to the outer peripheral surface, and an outer ring member that engages both ends of the bidirectional coil spring in a state where the inner ring member is inserted and fixed from the axial direction, and an inner surface of the outer ring member When the inner ring member is inserted in the axial direction with respect to the outer ring member, the one end and the other end of the bidirectional coil spring are allowed to be inserted, and the one end and the other end of the bidirectional coil spring are applied. And an engagement recess that holds the bidirectional coil spring in an engaged state, and is provided at a position facing the engagement recess and includes a restricting portion that prevents insertion of the bidirectional coil spring. And a recess having substantially the same shape, And said that you are.

  In the bidirectional torque limiter configured as described above, the bidirectional coil spring is tightly fitted and fixed to the inner ring member. This bidirectional coil spring is wound in a large number of rings and in a ring shape from one end to the other end, and when viewed from the axial direction, the one end side and the other end side extend linearly. It has a configuration. The outer ring member is formed to have a symmetrical shape over 360 ° in consideration of moldability and stability. An engagement recess is formed on the inner surface to allow insertion of one end and the other end of the bidirectional coil spring when the inner ring member is inserted into the outer ring member in the axial direction. A recess having a restricting portion having a substantially identical shape is formed at a position that is symmetrical to the center.

  In such a configuration, when the inner ring member to which the bi-directional coil spring is tightly fitted and fixed is inserted into the outer ring member from the axial direction, even if the bi-directional coil spring is to be inserted into the recessed portion in the axial direction, Since the insertion is not possible, the operator can insert the bidirectional coil spring at an appropriate position (engagement recess), and no malfunction occurs in the state where the inner ring member is assembled to the outer ring member. .

  According to the present invention, it is possible to obtain a bidirectional torque limiter that is easy to incorporate the inner ring member into the outer ring member and can exhibit stable performance.

It is a figure which shows one Embodiment of the bidirectional | two-way torque limiter of this invention, (A) is a disassembled perspective view which shows the whole structure, (B) is the figure which looked at the bidirectional coil spring from the axial direction. It is a figure which shows the structure of an inner ring member, (A) is a back view, (B) is a side view, (C) is a top view. It is a figure which shows the structure of an inner ring member, (A) is sectional drawing along the AA of FIG. 2 (A), (B) is a perspective view. It is a figure which shows the structure of an outer ring member, (A) is a back view, (B) is a side view, (C) is a top view. It is a figure which shows the structure of an outer ring member, (A) is sectional drawing along the BB line of FIG. 4 (A), (B) is a perspective view. It is a figure which shows the state which incorporated the bidirectional | two-way coil spring, (A) is a back view, (B) is sectional drawing along CC line of FIG. (A), (C) is D-- of FIG. Sectional drawing along D line.

Hereinafter, an embodiment of a bidirectional torque limiter according to the present invention will be described with reference to the accompanying drawings.
FIG. 1A is an exploded perspective view showing the overall configuration of the bidirectional torque limiter, and FIG. 1B is a view of the bidirectional coil spring viewed from the axial direction. As shown in the drawing, the bidirectional torque limiter 1 of the present embodiment includes an inner ring member 10 formed in a cylindrical shape, and an outer ring member 30 formed in a cap shape that is mounted so as to cover the inner ring member 10; And a bi-directional coil spring 70 that is fitted and fixed to the outer peripheral surface 10a of the circumferential wall 10b of the inner ring member 10.

  The bidirectional coil spring 70 is wound in a large number of rings and in a ring shape from one end 70a to the other end 70b. When viewed from the axial direction, the one end 70a extends linearly, The end portion 70b extends linearly in the direction opposite to the one end portion, and is separated from each other in a substantially linear shape. When the inner ring member 10 is incorporated into the outer ring member 30, such a bidirectional coil spring 70 has engagement recesses 35a, 70a, 70b formed on the inner surface 30c of the outer ring member 30, as described later. It is applied to the inner surface of 35 b and fixed to the outer ring member 30. The bidirectional coil spring may be either right-handed or left-handed.

  The bi-directional coil spring 70 slides when a predetermined rotational torque (rotational torque accompanying rotation in any direction of arrows D1 and D2) is generated from the inner ring member 10 or the outer ring member 30 (the inner ring member 10 and the outer ring 30). The power transmission between the member 30 and the member 30 is turned off. Specifically, in a state where the tightening force of the bidirectional coil spring 70 is strong, the inner ring member 10 and the outer ring member 30 rotate integrally even if the inner ring member 10 or the outer ring member 30 rotates in either direction of arrows D1 and D2. However, when a rotational torque stronger than the tightening force of the bidirectional coil spring 70 is generated (exceeds a predetermined rotational torque), the bidirectional coil spring 70 is moved from its end portion. Swells in a radial direction (relaxed state) due to the rotational force of the shaft, slip occurs between the outer peripheral surface 10a of the inner ring member 10 and the inner surface of the bidirectional coil spring 70 attached thereto, and the power transmission is turned off. .

  That is, such a bidirectional torque limiter 1 is always in a power transmission state in any rotational direction when the rotational force is small, and when the rotational force exceeds the tightening force (set torque) of the bidirectional coil spring 70, the inner ring Slip occurs between the member 10 and the outer ring member 30, and the power transmission is turned off. For this reason, the torque for turning off the power transmission can be adjusted by the tightening force of the bidirectional coil spring 70.

The configuration of the inner ring member 10 will be described with reference to FIGS. 2 and 3.
The inner ring member 10 is hollow and formed in a substantially cylindrical shape, and a drive shaft (not shown) is inserted through the internal passage 10A. The drive shaft is provided with a locking pin 80 (see FIG. 6B) in a direction orthogonal to the axial direction, and a notch recess 11 that engages with the locking pin has a diameter on one end side of the inner ring member 10. It is formed in the direction. Thereby, the inner ring member 10 is rotationally driven together with the rotational driving of the drive shaft, and the rotational driving force is transmitted to the outer ring member side.

  The inner ring member 10 includes a circumferential wall 10b, and the bidirectional coil spring 70 is fastened and fixed to the surface (outer peripheral surface 10a) thereof. A flange 12 is integrally formed on the circumferential wall 10b and restricts the movement of the bidirectional coil spring 70 fixed to the surface of the circumferential wall. The flange 12 is formed with an annular concave groove 12a on the side to which the bidirectional coil spring is fixed, and on the radially inner side thereof, an arcuate concave groove is provided via a rib 12c for the purpose of fleshing away during molding. A groove 12b is formed. Further, the inner side in the radial direction of the annular groove 12a is formed to be somewhat thick, and even if the bidirectional coil spring 70 is displaced in the axial direction, the end face thereof contacts the thick end face (regulating face) 12d. It is difficult to swell in the radial direction. The functions of the annular concave groove 12a and the end surface 12d will be described later.

The configuration of the outer ring member 30 will be described with reference to FIGS. 4 and 5.
The outer ring member 30 is formed in a cap shape, and includes a top wall 30 a and a circumferential wall 30 b that covers the circumferential wall 10 b of the inner ring member 10. A circular opening 31 into which the circumferential wall 10b of the inner ring member 10 is fitted is formed in the central region of the top plate wall 30a (see FIG. 6B). A projection 32 is formed on the top plate wall 30a so as to extend outward in the axial direction along the diametrical direction. The projection 32 can be engaged with a drive member (not shown). . That is, the bidirectional torque limiter 1 of the present embodiment is configured so that the engagement pin 80 (see FIG. 6B) of the drive shaft is engaged with the notch recess 11 formed in the inner ring member 10 so that the inner ring member side The driving force can be transmitted to the outer ring member side, and the driving member (not shown) is engaged with the protrusion 32 formed on the outer ring member 30 so that the driving force is transmitted from the outer ring member side to the inner ring member side. It is configured to be possible.

A bi-directional coil spring 70 wound around the outer peripheral surface 10a of the inner ring member is fixed to the inner surface of the circumferential wall 30b of the outer ring member 30 when the inner ring member 10 is inserted.
Hereinafter, the configuration of the inner surface of the outer ring member 30 will be described.

  The inner surface 30c of the circumferential wall 30b of the outer ring member 30 has a plurality of guide surfaces extending in the axial direction so as to prevent radial deformation of the bidirectional coil spring 70 with the inner ring member 10 inserted in the axial direction. Is formed. In this case, the guide surface is preferably configured such that the bi-directional coil spring 70 can contact over the entire 360 ° circumference. However, in consideration of moldability by the mold, die cutting, heat sink, and the like, the guide surface covers the entire surface. It is difficult to form the contact area, and a notch is formed along the circumferential direction so that the contact area is increased as much as possible. Specifically, the guide surface of the present embodiment is formed at two locations such that a pair of arcuate curved surfaces (also referred to as guide surfaces or contact walls) 37a and 38a extending in the axial direction oppose each other in the diameter direction. A total of four arcuate guide surfaces 37a and 38a are formed along the circumferential direction along the circumferential direction (in FIG. 4A, two places at the top and bottom). Further, on the inner surface 30c, a pair of guide walls 39, 40 having guide surfaces 39a, 40a having a substantially semicircular cross section extending in the axial direction at a predetermined interval are perpendicular to the diameter direction (FIG. 4). In (A), two locations are formed so as to oppose each other (two locations on the left and right) (a total of four guide walls 39 and 40 are formed).

  As a result, the two-way coil spring 70 fixed to the outer peripheral surface 10a of the inner ring member 10 hits the surface by the arcuate guide surfaces 37a and 38a formed at four locations along the circumferential direction, and was formed at four locations. By hitting points on the guide surfaces 39a and 40a, deformation in the radial direction is prevented. In this case, the guide surfaces 37a, 38a and 39a, 40a are arranged so as to be symmetric with respect to the central axis C, and the deformation of the bidirectional coil spring 70 is pressed in a balanced manner to provide a stable limiting torque. It can be generated.

  The guide surfaces 37a and 38a are integrally formed with the inner surface 30c via connecting ribs 43, respectively. In addition, on the front and back surfaces of the connecting rib 43, recesses 43a are formed on both sides in the axial direction in consideration of thermal sink marks during molding and moldability.

  As described above, when the inner ring member 10 is inserted and fixed in the outer ring member 30, both end portions 70a and 70b of the bidirectional coil spring 70 wound around the outer peripheral surface 10a of the inner ring member 10 are held in an engaged state. The outer ring member 30 is provided with engagement recesses 35a and 35b for holding the bidirectional coil spring 70 with both end portions 70a and 70b entering. In the present embodiment, the engagement recesses 35a and 35b are formed at the end using the arcuate guide surface (contact wall) described above, and as shown in FIG. The side surfaces of the guide surfaces 37a and 38a and the side surface of the connecting wall 43 that connects the guide surfaces 37a and 38a to the inner surface 30c are formed to be flush with each other along the extending direction of both end portions 70a and 70b.

  As a result, when the inner ring member 10 and the outer ring member 30 are assembled, the inner ring member 10 is moved to the outer ring member 30 while the one end portion 70a of the bidirectional coil spring 70 is aligned with the engagement recess 35a on the side surface of the guide surface 38a. When inserted, the other end portion 70b enters the engagement recess 35b on the side surface of the guide surface 37a and the bidirectional coil spring 70 is fixed to the outer ring member 30 at the time of final assembly.

  In addition, on the inner surface 30c of the outer ring member 30, it is preferable to form a notch 30e so as to turn inward according to the position where the engagement recesses 35a and 35b are formed. By forming such a notch 30e, the end portions 70a and 70b of the bidirectional coil spring do not interfere with the inner surface 30c when the inner ring member is inserted, and the insertion operation can be performed smoothly. . Moreover, it is preferable to provide the marking 47 on the opening edge of the outer ring member 30 so that the operator can visually recognize an appropriate insertion position when inserting the inner ring member 10.

  As described above, in the outer ring member 30, the guide surfaces 37a, 38a and 39a, 40a formed on the inner surface 30c are arranged so as to be point-symmetric about the central axis C. Similar recesses 35a ′ and 35b ′ are also formed at positions facing the positions where the mating recesses 35a and 35b are formed. By attaching the marking 47, a certain amount of erroneous insertion can be prevented. However, since the marking 47 is small, it is difficult to see, and there may be a case where the end portion 70a is erroneously inserted into the recess 35b ′.

  In the present invention, in order to prevent such erroneous insertion, the restricting portion is provided so that the end portions 70a and 70b of the bidirectional coil spring cannot be inserted into the recesses 35a 'and 35b'. In the present embodiment, as described above, since the engagement recesses 35a and 35b are formed using the arcuate guide surfaces (abutment walls) 37a and 38a, the end portions of the guide surfaces 37a and 38a are formed. The restricting portion 50 is formed by projecting, so that the end portions of the end portions 70 a and 70 b of the bidirectional coil spring 70 cannot be inserted by the restricting portion 50.

  In other words, the restricting portion 50 is formed so as to interfere (prevent insertion) in the intrusion direction of the end portion of the bidirectional coil spring, whereby the inner ring member 10 is inserted into the outer ring member 30 and the both are integrated. It is possible to reliably prevent erroneous insertion when assembling.

  Moreover, it is preferable to form a protrusion 54 protruding in the axial direction on the back surface of the top plate wall 30a of the outer ring member 30 on the side facing the engagement recesses 35a, 35b. The protrusion 54 is formed so as to abut against the bidirectional coil spring 70 when the inner ring member 10 is integrated with the outer ring member 30 and integrated with the exposed surface of the bidirectional coil spring 70 wound spirally. By attaching, the function of improving the sitting of the bidirectional coil spring 70 is achieved. Specifically, it is sufficient that the thickness of the bidirectional coil spring 70 to be wound is about half the diameter of the spring, so that the state of the bidirectional coil spring 70 wound around the inner ring member is stable and stable. Limiting torque can be generated.

  Further, a locking projection 56 that protrudes radially inward is formed at the opening end of the outer ring member 30. The locking projection 56 is provided to insert the inner ring member 10 into the outer ring member 30 and restrict the axial movement of the inner ring member 10 when both are in a predetermined position. By engaging with the outer peripheral edge 12e of the formed flange 12, the inner ring member 10 is fixed and secured to the outer ring member 30 in a positioned state (see FIGS. 3 and 6B).

  In the present embodiment, the bidirectional coil spring 70 is configured not to be detached from the inner ring member 10 in the assembled state of the inner ring member 10 described above. In particular, due to the downsizing of devices (copiers, etc.) in which the bidirectional lu limiter is installed, the bidirectional torque limiter is also required to be thin and thin in the axial direction and have a low torque type (for example, a limit torque of 400 g · cm or less) In such a bidirectional torque limiter, the wound bidirectional coil spring has a small diameter.

  The bi-directional torque limiter has a large load acting on the bi-directional coil spring for each limiter operation during forward rotation and reverse rotation.In particular, the load is large at the end, and it tries to spread it in the radial direction. The bidirectional coil spring itself repeats rising and lowering changes in the axial direction. In such a state, the bi-directional coil spring having a small wire diameter is detached from the outer peripheral surface of the inner ring member 10 on the locking side (the locking projection 56 side), or enters the contact portion with the outer ring member 30. There is a possibility that the behavior of the bidirectional coil spring 70 becomes unstable.

In the present embodiment, a structure for preventing the two-way coil spring 70 from coming off is provided, and the two-way coil spring 70 is configured not to be detached from the outer peripheral surface 10 a of the inner ring member 10.
Hereinafter, the detachment prevention structure of the present embodiment will be specifically described.

  As shown in FIGS. 2 and 3, a flange 12 is integrally formed on the outer peripheral surface 10a of the inner ring member 10, and the movement of the bidirectional coil spring 70 fixed to the surface of the circumferential wall 10b is restricted. . The flange 12 is formed with an annular groove 12a on the surface side around which the bidirectional coil spring 70 is wound. Further, as described above, arc-shaped guide surfaces (abutment walls) 37 a and 38 a are integrally formed on the inner surface 30 c of the outer ring member 30 via the connecting rib 43.

  And the end surface 60 by the side of the latching protrusion 56 of the guide surface (contact wall) 37a, 38a is formed so that it may become higher than the end surface 61 by the side of the latching protrusion 56 of the connection rib 43 (refer FIG. 5). ), The raised guide surfaces 37a and 38a are configured to fit into the annular concave groove 12a (see FIG. 6B). As a result, when the inner ring member 10 is assembled to the outer ring member 30 and both are fixed by the locking projections 56, the guide surfaces 37a and 38a of the outer ring member formed along the circumferential direction are formed on the flange 12 of the inner ring member. 6B, the bidirectional coil spring 70 wound around the guide surfaces 37a and 38a has an annular shape as shown in FIG. 6B. The movement in the axial direction is restricted by the restriction surface 12d on the radially inner side of the groove 12a, and the end sides of the guide surfaces 37a and 38a enter the annular groove 12a and get over (disengage) the guide surfaces 37a and 38a. Thus, it is possible to always generate a stable limit torque in the operating state.

  With respect to such a detachment prevention structure, the inner ring member 10 and the inner ring member 10 are arranged so that the end of the bidirectional coil spring 70 does not ride on the end surface of the contact wall (guide surface) on the outer ring member side that guides the bidirectional coil spring 70. As long as the engagement relationship is established between the two, the configuration can be modified as appropriate.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to above-described embodiment, It can change variously. For example, the configuration of the contact wall formed in the outer ring member 30 and the engagement recess can be appropriately modified. Further, the engaging recess may be formed in a portion other than the contact wall.

DESCRIPTION OF SYMBOLS 1 Bidirectional torque limiter 10 Inner ring member 30 Outer ring member 35a, 35b Engaging recess 35a ', 35b' Recess 37a, 38a Guide surface 43 Connecting rib 50 Control part 70 Bidirectional coil spring

Claims (5)

An inner ring member in which a bidirectional coil spring having one end extending linearly and the other end extending linearly in a direction opposite to the one end is fixed to the outer peripheral surface;
An outer ring member that locks both ends of the bidirectional coil spring in a state where the inner ring member is inserted and fixed from the axial direction;
A bidirectional torque limiter comprising
On the inner surface of the outer ring member,
When the inner ring member is inserted in the axial direction with respect to the outer ring member, the one end and the other end of the bidirectional coil spring are allowed to be inserted, and the one end and the other end of the bidirectional coil spring are in contact with each other. An engagement recess that holds the directional coil spring in an engaged state and a restriction portion that is provided at a position facing the engagement recess and prevents the bidirectional coil spring from being inserted, and is substantially the same as the engagement recess. A bidirectional torque limiter, wherein a recess having a shape is formed. The outer ring member is formed with a plurality of arc-shaped contact walls with which the bidirectional coil spring contacts along the circumferential direction,
2. The bidirectional torque limiter according to claim 1, wherein the engagement recess and the recess having the restricting portion are provided at an end of the arc-shaped contact wall.   The both sides according to claim 1 or 2, wherein the inner surface of the outer ring member is formed with a notch that allows the end of the bidirectional coil spring disposed in the engagement recess to escape. Torque limiter.   The bidirectional torque limiter according to any one of claims 1 to 3, wherein a marking indicating an insertion position of the inner ring member is provided on an opening edge of the outer ring member.   The outer ring member is provided with a protrusion that lifts the bidirectional coil spring in an axial direction in a state where the inner ring member is mounted on a side facing the portion where the engagement recess is provided. Item 5. The bidirectional torque limiter according to any one of Items 1 to 4.