JPH11336786A - Torque limiter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque limiter capable of easily carrying out assembly work and constantly providing a stable slipping state. SOLUTION: A ring groove 4a opened to the side of a first hub member 2 is formed on a second hub member 4, and the inside of the ring groove 4a is made a second spring winding part 4c. A lock part 4d extending from the deepest part of the ring groove 4a to the side of a first spring winding part 2a is formed on a cover 4b on the outside of the ring groove 4a. A winding end part 6a of a coil spring 6 is engaged with the lock part 4d. An inside diameter of the coil spring 6 becomes larger by revolving the second hub member 4. Additionally, the coil spring 6 is inserted into the ring groove 4a in a state where the inside diameter is made larger. When revolving force of the second hum member 4 is released, the coil spring 6 winds around the second spring winding part 4c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter incorporated in a paper feed mechanism or the like of a copying machine, and more particularly, to a coil spring pressed against a spring winding portion of a first hub member and a second hub member. The present invention relates to a torque limiter having a wound structure and transmitting power from one hub member to the other hub member by a frictional engagement force between an outer peripheral surface of a spring winding portion and an inner peripheral surface of a coil spring. .

[0002]

2. Description of the Related Art As a conventional torque limiter, a torque limiter described in Japanese Utility Model Laid-Open No. 2-66728 is representative. In the publication, a torque limiter according to a first embodiment has a support portion having an outer diameter larger than one end of a quenched spring winding portion and a central shaft hole. A first hub member having a D-shaped shaft hole, and a second hub member having a toothed portion meshed with the driving gear and having a boss portion as a spring wound portion. Are mounted on a rotating shaft (not shown) such that the ends of the shafts face each other. In addition, the first hub member has a spring winding portion and a second hub member.
A coil spring wound in a press-contact state across a spring winding portion of the hub member, and fitted on the outer peripheral surface of the coil spring, and one opening is formed on the support portion of the first hub member. A cover is provided which is fitted and the other opening is inserted into an annular recess formed in the tooth side surface of the second hub member. Still further, the outer peripheral surface of the spring winding portion of the first hub member and the inner peripheral surface of the coil spring can have a smooth slip state between the spring winding portion and the coil spring when an overload occurs. Is greased.

In a torque limiter having such a structure, a first hub member is rotatably mounted on a rotating shaft so as to be integrally rotatable, and a second hub member is rotatably supported on the rotating shaft via a bush. At the same time, the teeth of the second hub member are meshed with the driving gear. Therefore, power is transmitted from the gear to the rotating shaft via the torque limiter by the frictional engagement force between the inner peripheral surface of the coil spring and the outer peripheral surface of each spring winding portion. Further, when the load on the rotating shaft side is equal to or larger than a certain value, the coil spring is twisted in a direction in which one winding end side is fixed and the other winding end side expands in diameter. The frictional engagement force between the peripheral surface and the outer peripheral surface of the spring winding portion of the hub member is weakened, and the torque limiter enters a slip state. Then, transmission of power is cut off. Further, since the conventional torque limiter is provided with a cover that covers the outside of the coil spring, the scattering of grease during rotation is prevented.

[0004]

In such a torque limiter, one winding end of the coil spring is wound around the spring winding portion of the first hub member in a pressed state, and then the other end of the coil spring is wound. The winding end side is wound around the spring winding portion of the second hub member in a press-contact state. However, in the conventional torque limiter, the elastic deformation in the direction in which the diameter is increased by the cover is limited by the cover. The second inner surface of the coil spring
The outer peripheral surface of the spring winding portion of the hub member is press-fitted. That is, it is necessary to insert the spring winding portion of the second hub member into the inner peripheral surface of the coil spring while rotating the coil spring in the direction in which the diameter of the coil spring is expanded. Therefore, such assembling work is troublesome and productivity is low. Also, when the spring winding portion of the second hub member is pressed into the inner peripheral surface of the coil spring without rotating, the inner peripheral surface of the coil spring rubs against the outer peripheral surface of the spring winding portion, causing scratches, It is recalled that since the coil spring is deformed, a quality problem that a stable slip state cannot be obtained is caused.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a torque limiter that can easily perform an assembling operation and always obtain a stable slip state.

[0006]

In order to achieve such an object, a torque limiter according to a first aspect of the present invention includes a first spring winding portion (reference numeral 2a in the embodiment, hereinafter referred to as "1a").
Similarly, a first hub member (2) provided with a first support portion (2b) having a large outer diameter at one end and an opening on the side of the first hub member (2). An annular groove (4a) is formed, and a cover (4b) provided outside the annular groove (4a) and having a front end fitted to the first support portion (2b); A second spring-wound portion (4c) provided on the inner side of the first spring-wound portion (2a) and an inner peripheral surface of the cover (4b); A second hub member (4) having a locking portion (4d) provided from the deepest portion of the annular groove (4a) to the outside of the first spring winding portion (2a). The first spring-wound portion (2a) and the second spring-wound portion (4c) are wound in a press-contact state across the first spring-wound portion (2c) and disposed inside the cover (4b). And a coil spring (6) provided with one winding end (6a) that is circumferentially engageable with the locking portion (4d) of the second hub member (4), By moving the second hub member (4) toward the first hub member (2) while rotating the second hub member (4) against the self-returning force of the coil spring (6), the diameter is increased. The coil spring (6) is inserted into the annular groove (4a) and releases the turning power of the second hub member (4), so that the coil spring (6) is turned into the second spring. It is characterized by being wound around the winding part (4c) in a pressure contact state.

Further, the torque limiter according to claim 2 is a torque limiter according to claim 1,
The first hub member (2) is provided with a second support portion (2c) having a small outer diameter at the other end of the first spring winding portion (2a). The second hub member (4) is rotatably supported by a support portion (2c).

According to a third aspect of the present invention, there is provided a torque limiter according to the first or second aspect, wherein the inner peripheral surface of the cover (4b) of the second hub member (4). And extends from the innermost surface thereof in the center direction to extend from the deepest part of the annular groove (4a) to the outside of the first spring winding part (2a), and at intervals in the circumferential direction. A plurality of the locking portions (4d) formed
Is provided.

According to a fourth aspect of the present invention, there is provided the torque limiter according to any one of the first to third aspects, wherein the other winding end (6b) of the coil spring (6) is provided on the outside. And is separated from the first spring winding part (2a).

According to a fifth aspect of the present invention, in the torque limiter according to any one of the first to fourth aspects, the first spring winding portion of the first hub member (2) is provided. A gap adjusting member (7) is interposed between the side surface transitioning from (2a) to the first support portion (2b) and the side surface of the other winding end (6b) of the coil spring (6). It is characterized by being.

[0011]

FIG. 1 shows an embodiment of the present invention.
The torque limiter shown in FIG. 2 is a power transmission device incorporated in a paper feed mechanism of a copying machine. When a load exceeding a certain level is applied to a rotating shaft on which a paper feed roller is mounted due to paper jam, the torque limiter rotates. It has a function of interrupting the transmission of power to the shaft. 1 is a sectional view of a torque limiter, and FIG. 2 is a sectional view taken along line AA of FIG. Hereinafter, embodiments of these drawings will be described.

A first hub member 2 made of iron and having a stepped outer peripheral surface is mounted on a rotating shaft 1 on which a paper feed roller (not shown) is mounted. The first hub member 2 has a cylindrical first shape around which a coil spring 6 described later is wound.
, A ring-shaped first support portion 2b formed at one end of the first spring wound portion 2a and having an outer diameter larger than that of the first spring wound portion 2a, and a first spring wound portion. A cylindrical second support portion 2c formed at the other end of the portion 2a and having a smaller outer diameter than the cylindrical second support portion 2c formed at the first support portion 2b side; It has a shape having an attachment portion 2d. The groove 2 formed on the side surface of the mounting portion 2d
The first hub member 2 is rotatably mounted on the rotary shaft 1 so as to rotate integrally with the rotary shaft 1 by fitting the pin 3 inserted into the through hole of the rotary shaft 1 into e.

A second hub member 4 made of a synthetic resin material is rotatably supported by the second support portion 2c of the first hub member 2 and is prevented from falling off by a snap ring 5.
The second hub member 4 is formed with an annular groove 4a opened toward the first hub member 2 side. Outside the annular groove 4a, a cylindrical cover 4b whose tip is fitted to the first support portion 2b of the first hub member 2 is provided. Inside the annular groove 4a, a coil described later is provided. A cylindrical second spring winding portion 4c around which the spring 6 is wound is provided. Further, the inner peripheral surface of the cover 4b protrudes from the inner peripheral surface toward the center and extends from the deepest portion of the annular groove 4a to the first spring winding portion 2.
The locking portion 4d extending to the outside of the portion a is integrally formed. In this embodiment, locking portions 4d are formed at positions where the inner peripheral surface of the cover 4b is divided into four equal parts, and the distal end of each locking portion 4d is in contact with the outer peripheral surface of a coil spring 6 described later. It is formed on a separated arc surface. Further, the side of the second hub member 4 which is prevented from falling off by the snap ring 5 is:
The gear 4e meshes with a driving gear (not shown).

In this embodiment, the outer diameter of the second spring member 4c of the second hub member 4 is smaller than the outer diameter of the spring member 2a of the first hub member 2. Very small but large.

The first hub member 2 having such a shape
A coil spring 6 is provided in an annular space S (including the annular groove 4a) formed outside the spring winding portions 2a and 4c of the second hub member 4 and inside the cover 4b of the second hub member 4.
Are arranged. The coil spring 6 is formed so that its winding diameter is smaller than the diameter of each of the spring winding portions 2a and 4c, and is wound in a press-contact state on each of the spring winding portions 2a and 4c by a self-returning force (elastic force). Have been. One winding end 6a of the coil spring 6 is bent in the radial direction so as to engage with the locking portion 4d of the cover 4b in the circumferential direction. Further, the other winding end 6b of the coil spring 6 is bent outward so as not to contact the inner peripheral surface of the cover 4b, and is separated from the outer peripheral surface of the first spring winding portion 2a. This is to prevent the winding end portion 6b of the coil spring 6 and the spring winding portion 2a from galling when the torque limiter is slipped.

Further, the torque limiter of this embodiment is configured such that the first spring member 2a of the first hub member 2
A gap adjusting member 7 made of metal or synthetic resin is interposed between the vertical side surface that shifts to the supporting portion 2b and the side surface of the other winding end 6b of the coil spring 6. The gap adjusting member 7 prevents the coil spring 6 from being deviated in the axial direction by repeating transmission of the power or interruption of the transmission, and galling between the vertical side surface and the winding end 6b of the coil spring 6. It is an inclusion prepared to prevent the phenomenon.

Next, the procedure for assembling the torque limiter having such a structure will be described. First, grease is applied to the outer peripheral surface of the first spring winding portion 2a of the first hub member 2 and the inner peripheral surface and the outer peripheral surface of the coil spring 6, and then the coil spring 6 is turned in the direction in which the diameter of the coil spring 6 increases. Meanwhile, the spring winding portion 2 of the first hub member 2 on which the gap adjusting member 7 is mounted
a is inserted into the coil spring 6 from the winding end 6b side. Also, the second support portion 2c of the first hub member 2
While the hub member 4 is fitted, the winding end 6a of the coil spring 6 is engaged with the locking portion 4d. By moving (pressing) the second hub member 4 toward the first hub member 2 while rotating the second hub member 4 against the self-returning force of the coil spring 6, The winding end 6a side of the coil spring 6 whose diameter has been increased is inserted into the annular groove 4a. Further, after the side surface of the second spring winding portion 4c is abutted against the end of the first spring winding portion 2a, the coil spring 6 releases the turning power of the second hub member 4 so that the coil spring 6 It is wound in pressure contact with the second spring winding part 4c.

The thus assembled torque limiter is mounted on the rotating shaft 1 after the second hub member 4 is prevented from coming off by the snap ring 5. In addition, by fitting the pin 3 into the groove 2 e of the first hub member 2, the first
The hub member 2 is pivotally attached to the rotating shaft 1 so as to freely rotate integrally therewith. The pin 3 is opposite to the pin 3 in the axial direction (the second support 2
At the end (c), a means for restricting movement similar to that of the snap ring 5 is provided. That is, the movement of the torque limiter supported on the rotating shaft 1 and meshed with a gear (not shown) is restricted in the axial direction.

The torque limiter having the above-described structure is arranged such that when a gear (not shown) meshed with the gear 4e of the second hub member 4 rotates by motor control on the driving side, the inner peripheral surface of the coil spring 6 and the spring Power is transmitted to the rotating shaft 1 by a frictional engagement force with the outer peripheral surfaces of the winding portions 2a and 4c. Then, the copy paper in a paper feed cassette (not shown) is fed into the copying machine main body (not shown) on the photosensitive drum side by a frictional force with a rubber roller (not shown) mounted on the rotating shaft 1. Note that grease scattered during rotation of the torque limiter is prevented from scattering to the outside by the cover 4b.

Further, when a paper jam occurs in such a paper feeding mechanism, the load on the rotating shaft 1 becomes greater than a predetermined value, so that the winding end 6b of the coil spring 6 is braked. Further, in this state, the winding end 6a side of the coil spring 6 is twisted in the direction in which the diameter is increased by the rotation of the second hub member 4, so that the inner peripheral surface of the coil spring 6 and the outer peripheral surfaces of the spring winding portions 2a and 4c. And the frictional engagement force with
The torque limiter enters a slip state.

As described above, the torque limiter incorporated in the paper feeding mechanism of the copying machine has been described as an embodiment of the present invention. However, the torque limiter of the present invention can be incorporated in other devices. The winding end 6a of the coil spring 6 is provided with a protruding locking portion 4 provided on the inner peripheral surface of the cover 4b.
Instead of engaging with d, it may be engaged with a concave groove provided on the inner peripheral surface of the cover 4b. Further, the second hub member 4 is rotatably supported by the first support portion 2c of the first hub member 2. However, the first support portion 2c is eliminated and the second hub member 4 is rotated by the rotation shaft. 1 may be directly supported. In the embodiment, since the second hub member 4 is formed of a synthetic resin, there is no need to interpose a bearing.

Further, the first hub member 2 and the rotating shaft 1 are
A unit other than the pin 3 can be freely rotatably mounted on the shaft. Further, at the time of assembling, the side surface of the engaging portion 6a that slides in a state where the winding end portion 6a of the coil spring 6 is pressed is described as a flat surface, but the second hub member 4 is connected to the first hub. A tapered surface in which the amount of protrusion in the direction in which the coil bobbin 6 expands increases toward the deepest side of the annular groove 4a so that the coil spring 6 expands in diameter as the coil spring 6 moves (pushes in) to the member 2 side. It may be. Further, the first hub member 2 is used as a driven side rotating member,
Although the hub member 4 described above is described as a rotating member on the driving side, the first hub member 2 can also be used as a rotating member on the driving side.

[0023]

As described above, in the torque limiter according to the first aspect, the locking portion is provided on the inner peripheral surface of the cover of the second hub member, and the coil spring is freely engageable with the locking portion. The coil spring is moved toward the first hub member while the second hub member is rotated against the self-returning force of the coil spring, so that the coil spring is wound around the second spring. Since the outer peripheral surface of the spring-wound portion of the second hub member is rubbed against the inner peripheral surface of the coil spring during assembly, the problem is solved. . In addition, the work of winding the coil spring around the second spring winding portion can be easily performed. Therefore,
It is possible to provide a torque limiter that can easily perform an assembling operation and always obtain a stable slip state.

Further, the torque limiter according to claim 2 is the torque limiter according to claim 1,
The second end having a small outer diameter is provided at the other end of the first spring winding portion.
Is provided on the second support portion of the first hub member.
The second hub member is rotatably supported.
When the hub member is moved to the first hub member side, the center of the second hub member is not eccentric with respect to the center of the coil spring, so that the assembling operation can be facilitated.

According to a third aspect of the present invention, there is provided the torque limiter according to the first or second aspect, wherein the center of the second hub member is provided on the inner peripheral surface of the cover. Direction, extending from the deepest portion of the annular groove to the outside of the first spring winding portion, and provided with a plurality of locking portions formed at intervals in the circumferential direction. When the coil spring is wound around the spring winding portion or when the rotating shaft rotates in the reverse direction, the coil spring can be restricted by the locking portion so as not to be largely deformed (expanded in diameter). Therefore, a torque limiter having excellent durability can be provided.

According to a fourth aspect of the present invention, in the torque limiter according to any one of the first to third aspects, the other end of the coil spring is bent outward to form the first spring winding. Since it is separated from the winding portion, the galling between the winding end portion and the spring winding portion can be prevented. Therefore, since the set value of the power transmission force (rotation torque) due to the frictional engagement force between the inner peripheral surface of the coil spring and the outer peripheral surface of the spring winding portion does not change, a highly reliable torque limiter can be provided.

According to a fifth aspect of the present invention, there is provided the torque limiter according to any one of the first to fourth aspects, wherein the first support member is provided with a first support member extending from the first spring winding portion of the first hub member. The gap adjusting member is interposed between the side surface transitioning to the portion and the side surface of the other winding end of the coil spring, so that the coil spring is deviated in the axial direction and the side surface of the first hub member and the winding of the coil spring. Galling with the edges is prevented. Therefore, the set value of the power transmission force (rotation torque) due to the frictional engagement force between the inner peripheral surface of the coil spring and the outer peripheral surface of the spring winding portion does not fluctuate.
A highly reliable torque limiter can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a torque limiter shown as an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 2 1st hub member 2a 1st spring winding part 2b 1st support part 2c 2nd support part 4 2nd hub member 4a ... annular groove 4b ... cover 4c ... 2nd spring Winding part 4d: locking part 6: coil spring 6a: winding end 6b: winding end 7: gap adjusting member

Claims (5)

[Claims] 1. A first hub member provided with a first support portion having a large outer diameter at one end of a first spring winding portion, and an annular shape opened on the first hub member side. A cover provided outside the annular groove and having a distal end fitted to the first support portion, and a side surface provided inside the annular groove and having a side surface formed by the first spring winding. A second spring wound portion in contact with the other end of the portion, and a lock provided on an inner peripheral surface of the cover and extending from a deepest portion of the annular groove to outside of the first spring wound portion. A second hub member having a first portion and a second portion wound around the first spring-wound portion and the second spring-wound portion in a press-contact state and disposed inside the cover. A coil spring provided with one of the winding ends that is circumferentially engageable with the locking portion of the second hub member, In the state where the second hub member is rotated against the self-return force of the coil spring, the first hub is rotated.
By moving to the hub member side, the coil spring whose diameter has been increased is inserted into the annular groove, and the coil spring is released by releasing the rotational power of the second hub member. 2. A torque limiter wound around a second spring winding portion in a pressure contact state. 2. The torque limiter according to claim 1, wherein the first hub member has a second support portion having a small outer diameter at the other end of the first spring winding portion. A torque limiter provided, wherein the second hub member is rotatably supported by the second support portion. 3. The torque limiter according to claim 1, wherein an inner peripheral surface of the cover of the second hub member projects from the inner peripheral surface in a center direction to form the annular groove. A torque limiter extending from the deepest portion to the outside of the first spring winding portion and provided with a plurality of the locking portions formed at intervals in a circumferential direction. 4. The torque limiter according to claim 1, wherein the other end of the coil spring is bent outward and is separated from the first spring winding part. Characteristic torque limiter. 5. The torque limiter according to claim 1, wherein the first hub member has a first hub member.
Between the side surface transitioning from the spring winding portion to the first support portion and the side surface of the other winding end of the coil spring;
A torque limiter comprising a gap adjusting member interposed.