JP2006226408A - Torque limiter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and low-cost torque limiter which is used for a paper coordinating part or the like, with a high torque maintained. <P>SOLUTION: One side of a support frame 2 is fitted to a stage 1 by a locking shaft. A coil spring 4 is interposed between the other side of the support frame 2 and the stage 1, with guide slopes 11 and 11 provided to face a roller support hole provided to the support frame. Each of the guide slopes 11 is provided with a slidable side board member 5. A tapered part 13 having a wedge angle β is provided to the surface facing each of the side board members 5. The tapered part 13 is engaged with a tapered recess 22 on both end faces of a roller 3 engaged with the roller support hole. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a low-cost and compact torque limiter that can be used for office machines such as copiers and printers that are becoming more cost-effective and compact.

  As a torque limiter used in a paper separation section of office equipment, a driven roller pressed against the feeding roller with a required nip pressure is fitted to the fixed drum, and the outer diameter surface of the fixed drum and the driven roller are A coil spring is interposed between the inner diameter surface. A torque limiter in which one end portion of the coil spring is engaged with the inner diameter surface of the driven roller and the other end side is wound around the fixed drum with a predetermined binding force is known (Patent Document 1). .

  In addition, as a torque limiter suitable for downsizing, a sleeve with a slit or a coil spring having elasticity in the required diameter reducing direction is fitted to the outer diameter surface of the outer member fitted to the inner member, and the inner force is applied by the spring force. Conventionally known is a technique in which a required radial force is applied to a sliding contact surface between a member and an external member, and a required torque is generated by relative rotation of both members (Patent Document 2).

  All of these torque limiters are insufficient to meet the demands for cost reduction and compactness that are progressing in the field of office equipment. And a novel torque limiter that is completely different in the torque generation mechanism (Japanese Patent Application No. 2004-328030).

  As shown in FIG. 6, the torque limiter according to the proposal has tapered portions 32, 32 provided on the opposed surfaces of the pair of opposed side plate members 31, 31, and each of the shafts 34 penetrated by the rollers 33. The side plate members 31 and 31 are press-fitted and fixed, and the tapered portions 32 and 32 are brought into contact with the inclined surfaces 35 and 35 at both end faces of the roller 33 so that torque is generated on the contact surfaces.

  Support arms 37, 37 provided on a base 36 are penetrated in the radial direction at the outer ends of the pair of side plate members 31, 31 coupled by the shaft 34, and are attached to the support arms 37, 37. Coil springs 38, 38 are pressed against the outer end portions of the side plate members 31, 31, and the rollers 33 are urged upward via the side plate members 31, 31, and the feed rollers are pressed against the rollers 33. 39, a constant nip pressure is generated.

  In the torque limiter having the above configuration, the wedge angle θ is an angle formed by the tapered portions 32 and 32 of the side plate members 31 and 31 with respect to the radial direction of the roller 33. When a radial load is applied from the roller 33, torque is generated by contact between the tapered portions 32, 32 having the wedge angle θ and the inclined surfaces 35, 35. By setting the wedge angle θ to be relatively small, the frictional force on the contact surface is increased, and a larger torque can be generated.

The above torque limiter does not require a special component such as a spring as a torque generating component, and thus can be made compact. In addition to the function of generating the nip pressure, the coil springs 38 and 38 have the function of generating the torque, so that the number of parts can be reduced.
JP-A-8-2726 (FIG. 2, paragraph 0022) JP 2003-156066 A

  The torque limiter according to the above-mentioned patent application can achieve the intended purpose in that the cost can be considerably reduced and the size can be reduced as compared with the conventional one. However, when the inclined surfaces of both ends of the roller are strongly pressed against the tapered portion of the side plate member, the side plate member is displaced due to the pressure and the generated torque is reduced.

  Accordingly, it is an object of the present invention to provide a torque limiter which can stabilize the position of the side plate member and can generate a large torque stably by providing a support structure for the side plate member.

  In order to solve the above-described problems, the present invention is configured such that one side portion of a support frame is attached to a base by a swing shaft, and an elastic member is interposed between the other side portion of the support frame and the base. The support frame is provided with a roller support hole, and inwardly inclined guide surfaces are provided on two surfaces of the roller support hole opposite to the axial direction of the swing shaft, and each inclined guide surface is provided in the inclined direction. A side plate member is slidably fitted, and a tapered portion having a wedge angle defined by an inclination angle with respect to the axis is formed on the opposing surface of each side plate member, and the rollers are coaxially disposed between the tapered portions of the side plate members. In addition to being fitted, the tapered portion is fitted into the tapered recesses on both end faces of the roller.

In the torque limiter configured as described above, the feeding roller is pressed onto the roller, and the pressing force and the elastic force of the elastic member are balanced to generate a constant nip pressure.
The roller exerts a radial force on the tapered portions of both side plate members, and generates torque on the mating surface between the tapered concave portion and the tapered portion of the side plate member having a wedge angle. At the same time, an outward force acts on the side plate members, and each side plate member is pressed against the inclined guide surface of the support frame. Each side plate member is pressed inward by the reaction force, and the torque on the fitting surface between the tapered portion and the tapered concave portion is increased.

  A shaft portion that protrudes coaxially is provided at the tip of one taper portion of the side plate member, and a shaft hole is provided in the other taper portion, and the shaft portion penetrates the center hole of the roller and the shaft hole By adopting a configuration penetrating through the both sides, the radial positioning of both side plate members and the rollers is performed.

  As described above, according to the present invention, when used in the paper separating unit, the urging means for generating the nip pressure between the urging means for generating the torque required for the paper separating and the feeding roller. Since the means is shared by one elastic member, the structure is simplified. Further, even if the roller is strongly pushed in the radial direction between the side plate members and both side plate members are strongly pushed outward, the back surface of the side plate member is supported by the support frame, so the roller is tapered. Torque due to friction between the side plate member and the tapered portion of the side plate member can be reliably generated. In addition, when the roller is replaced due to wear of the torque generating portion or the like, it can be easily replaced by removing both side plate members from the support frame, and reassembly is also simple.

  Further, the side plate member is pushed inward from the inclined guide surface of the support frame, and this has the effect of further increasing the torque generated on the fitting surface of the tapered portion and the tapered recess.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The torque limiter of the embodiment shown in the drawings includes a base 1, a support frame 2, a roller 3, a coil spring 4 as urging means, and a pair of side plate members 5 and 5.

  As shown in FIGS. 3 and 5, the support frame 2 is swingably supported by a support shaft 6 established on the base 1 by a swing shaft 7 parallel to the base 1. As shown in FIGS. 3 and 5, the support frame 2 has a rectangular frame shape, and the swing shaft 7 is inserted into a pair of opposed arms 8, 8 provided on one side thereof. Further, a coil spring 4 is interposed between the lower surface of the side edge opposite to the side edge through which the swing shaft 7 is inserted and the base 1 so that the support frame 2 faces upward with respect to the base 1 ( It is energized in a direction away from the base 1.

  The support frame 2 is provided with a rectangular roller support hole 9 penetrating through the upper and lower surfaces thereof. The roller support hole 9 is formed so that two surfaces along the axial direction of the rocking shaft 7 are perpendicular to the upper and lower surfaces, and two surfaces perpendicular to these two surfaces, that is, the rocking shaft 7. The two surfaces facing in the axial direction are inclined guide surfaces 11 and 11 which are inclined at a constant angle α (see FIG. 1A) toward the center. In addition, vertical guide grooves 12 and 12 are provided at the center of each inclined guide surface 11.

  Side plate members 5, 5 are provided along the inclined guide surfaces 11, 11. Each of the side plate members 5 and 5 is a tapered portion 13 in which a cylindrical body having the same diameter having a center line parallel to the swing shaft 7 forms a main body portion, and the central portion protrudes in the direction of the other side on mutually facing inner surfaces. Is formed. An inclination angle with respect to the axis of the tapered portion 13 is defined as a wedge angle β.

  A shaft portion 14 projecting in the opposite direction is provided at the center of the tip of the tapered portion 13 of the one side plate member 5, and a through hole 15 extending from the tip to the outer end surface is provided in the tapered portion 13 of the other side plate member 5. It is done. The shaft portion 14 is slidably fitted into the through hole 15 so as to be slidable, and there is a constant interval between the tips of both the tapered portions 13 and 13 even in the deepest fitted state (FIG. 1A). reference).

  An outer end surface 16 (see FIG. 5) of the side plate member 5 facing the inclined guide surface 11 of the support frame 2 has the same inclination angle as the inclined guide surface 11 and is slidably fitted into the guide groove 12. Matching guide ribs 17 are provided.

  The roller 3 includes a roller body 19 having a center hole 18 and a rubber roller 21 mounted around the roller body 19, and tapered recesses 22 that match the wedge angle β are formed on both end surfaces of the roller body 19. The center hole 18 has a slightly larger diameter than the shaft portion 14.

  The roller 3 and the side plate members 5 and 5 are assembled by inserting the shaft 14 of one side plate member 5 from one end thereof into the center hole 18 of the roller 3 (see arrow A in FIG. 4) and the other end. The other side plate member 5 is inserted through the center hole 18, the shaft portion 14 is fitted into the through hole 15, and the tapered portion 13 is fitted into the tapered recess 22. After assembling the roller 3 and the pair of side plate members 5 and 5 in this way, they are inserted into the support hole 9 (see arrow B in FIG. 4).

The torque limiter of the embodiment is configured as described above, and the operation thereof will be described next. In the assembled state as shown in FIG. 1A, the feeding roller 23 is pressed against the roller 3, and a nip pressure P is generated between the rollers 3 and 23 due to balance with the elastic force of the coil spring 4. The roller 3 is pushed in the radial direction by the feeding roller 23, and a pressing force F ₁ generated according to the size of the wedge angle β between the tapered concave portion 22 on both end faces and the tapered portion 13 of the side plate members 5, 5. As a result, a predetermined torque is generated (see FIG. 1B).

  Further, when the roller 3 is pushed in the radial direction, both side plate members 5 and 5 press the inclined guide surfaces 11 and 11 of the support frame 2, but the side plate members are supported by the support frame 2. Therefore, the torque according to the wedge angle β is stably exhibited.

On the other hand, since the inclined guide surface 11 of the support frame 2 has the inclination angle α, the horizontal component force F ₂ of the radial pressing force acting from the roller 3 through the side plate member 5 as described above becomes the inclination angle α. Occurs at a corresponding size. It increases the frictional force at the contact surface between the tapered portion 13 of the tapered recess 22 and the side plate member 5 of the roller 3 by a reaction force of the horizontal force F _2, to increase the generated torque of the results above. In this case, since the wedge angle β is set to be relatively small, the tapered portion 13 becomes sharp, and a larger torque is generated in the pressing force from the inclined guide surface 11. That is, the generated torque is not only the torque generated when the roller 3 presses the tapered portion 13 of the side plate member 5 but also the force in the direction in which the side plate member 5 moves inward along the inclined guide surface 11 of the support frame 2. the acts horizontal force F _2, since the pinching strongly roller 3 side plate member 5 from both sides by the reaction force, generated torque is to further increase.

Even when the side plate members 5 and 5 are pushed inward by the horizontal component force F ₂ , there is a gap between the tips of the tapered portions 13 and 13 of the side plate members 5 and 5. Movement to is not hindered. The nip pressure P acts on the shafts 14 and 14 of the side plate members 5, but the contact surfaces of the shafts 14 and 14 are present in the surface on which the nip pressure P acts, so that the strength is sufficiently exhibited. The deformation of the shaft 14 due to the pressure P is prevented.

(A) Cross-sectional view of the embodiment, (b) Action explanatory diagram Side view Same as above Exploded sectional view Exploded perspective view Cross section of conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 2 Support frame 3 Roller 4 Coil spring 5 Side plate member 6 Support | pillar 7 Oscillating shaft 8 Arm 9 Roller support hole 11 Inclined guide surface 12 Guide groove 13 Tapered portion 14 Shaft portion 15 Through hole 16 Outer end surface 17 Guide rib 18 Center hole 19 Roller body 21 Rubber roller 22 Tapered recess 23 Feed roller

Claims (2)

  One side of the support frame is attached to the base by a swing shaft, an elastic member is interposed between the other side of the support frame and the base, and a roller support hole is provided in the support frame. An inwardly inclined guide surface is provided on two surfaces of the roller support hole facing the axial direction of the swing shaft, and a side plate member is fitted to each inclined guide surface so as to be slidable in the inclined direction. Taper portions each having a wedge angle defined by an inclination angle with respect to the axis line are formed on the opposite surfaces of the side plates, and the rollers are fitted coaxially between the taper portions of the side plate members, and tapered recesses on both end surfaces of the rollers A torque limiter in which the taper portion is fitted to the torque limiter. A shaft portion protruding in a coaxial state is provided at the tip of one taper portion of the side plate member, and a shaft hole is provided in the other taper portion, and the shaft portion penetrates the center hole of the roller and the shaft hole The torque limiter according to claim 1, wherein the torque limiter is passed through the shaft.

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