JPH05164140A - Torque limiter - Google Patents

Abstract

PURPOSE:To provide different torque limit values in the right and left directions of rotation by journaling an inner ring to the inside of an outer cylindrical member, wrapping a coil spring ground the outer peripheral surface of the inner ring and inserting the circular ring part of a cover-member between the large diameter part of the coil spring and the outer cylindrical member. CONSTITUTION:A spring inserting part 2 is formed inside an outer cylindrical member 1, and an inner ring 4 is journaled to a bearing part 3 installed in the depth of the spring inserting part. Besides, a coil spring 5 consisting of different diameter parts, namely of a small diameter part 5a and a large diameter part 5b extending in the axial direction, is arrangedon the outer peripheral surface of the inner ring 4. Further, a cover-member 6 turnably fitted on the inner ring 4 is fitted in one end part of the outer cylindrical member 1. A circular ring part 6a facing inward is formed in the cover-member 6 to be interposed between the large diameter part 5b of the coil spring 5 and the inner diameter part of the outer cylindrical member 1. On the other hand, the outer diameter of the circular ring part 6a and the inner diameter of the outer cylindrical member 1 are formed so that eccentric curvature parts exist at plural concentric opposite places. Thus, different torque limit values are obtained in the right and left directions of rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter used in a rotating part of OA equipment such as a copying machine, a facsimile, a laser beam printer and the like.

[0002]

2. Description of the Related Art Generally, a torque limiter transmits a rotational force above a preset torque value in order to protect the drive unit when an overload or impact force is applied to the driven unit for some reason in a rotary shaft system. It is provided at an appropriate position of the shaft system as a means for shutting off.

However, the torque limiter is not limited to such a method of use, and is used, for example, in a device for preventing double feeding of paper in various office equipment, a brake for back tension of a continuous paper drawing section, or a cover plate for OA equipment. It is also used for the opening and closing mechanism of.

FIG. 6 shows an example of a torque limiter used in the above-described paper double feed prevention device and the like. This torque limiter accommodates a coil spring 13 in a spring insertion portion 12 of an outer ring 11 serving as an outer member, and engages a hook 14 provided at one end of the coil spring 13 with a recess 16 in an end wall 15 of the outer ring 11. , The hook 14 ′ provided at the other end engages with the recess 16 ′ of the lid 17 fitted and fixed in the open end of the outer ring 11, and the inner ring 18 as the inner member inserted into the coil spring 13 is inserted into the outer ring 11. It has a structure in which it is rotatably supported by a bearing portion 19 of 11 and a lid 17.

On the other hand, when a torque limiter is used for the cover plate opening / closing mechanism of OA equipment, it operates with a small torque limit value so that it can be smoothly rotated when lifting the cover plate, and when lowering the cover plate. There is a need for a torque limiter that operates with a large torque limit value that can hold the lid plate so that it does not drop suddenly and that has different torque limit values for both forward and reverse rotation directions.

As a torque limiter having different torque limit values for transmitting different rotational torques in both the forward and reverse directions, an inner ring and an outer ring are fitted around a rotating shaft to connect the rotating shaft and the inner ring. The torque limiters acting in opposite directions are provided between the inner ring and the outer ring in a double manner. For example, the torque limiter between the inner ring and the outer ring forms a plurality of inclined wedge-shaped spaces with respect to the inner diameter surface of the outer ring. Surface,
Japanese Patent Application No. 2-296202 has already proposed a structure in which a roller is installed in each wedge-shaped space and the roller is pressed by a torque setting spring toward a narrow portion of the wedge-shaped space.

[0007]

Among the examples of the torque limiter described above, the former one has a simple mechanism, and the fine adjustment of the set torque limit value can be performed by adjusting the spring force of the coil spring fixed to the cover. It can be easily adjusted by rotating. However, this type of torque limiter is configured as a torque limiter in one direction, and different torque limit values cannot be set in both forward and reverse directions.

In the latter case, it is possible to set different torque limit values in both the forward and reverse directions, but a unidirectional torque limiter operating in the opposite directions is provided between the rotary shaft and the inner ring and between the inner ring and the outer ring. Since they are provided in duplicate, the mechanism is complicated and therefore the number of parts is large, so that various points such as assembly workability cannot be satisfied.

The present invention has been made to solve many problems of the above-described conventional torque limiter, in particular, the torque limiter having different torque limit values in both forward and reverse directions. With a simple structure with a coil spring between them, it can operate in the left-right rotation direction and set different torque limit values in both rotation directions, and the set torque limit value can be adjusted simply by rotating the lid member. It is an object of the present invention to provide a torque limiter that is small in number, inexpensive, and therefore excellent in workability and maintenance and inspection.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to an outer cylinder member, an inner ring rotatably supported inside thereof, a small diameter portion and a large diameter portion incorporated in the outer periphery thereof and extending in the axial direction. And a lid member that is fitted to the other end of the outer tubular member and is rotatably fitted over the inner ring. The small diameter portion of the coil spring is slightly larger than the outer diameter of the inner ring. The lid member has an annular portion facing inward, and the annular portion is interposed between the large diameter portion of the coil spring and the inner diameter of the outer tubular member, and the outer diameter of the large diameter portion is set. Is provided so as to have a slight interference fit with respect to the inner diameter of the annular portion, and the eccentric curvature surface is formed at least at two or more locations on the concentric circle where the outer diameter of the annular portion and the inner diameter of the corresponding portion are The torque limiter is configured to have.

In this solution, notches may be provided at appropriate positions on the annular portion.

[0012]

The torque limiter of the present invention having the above-described structure acts as a torque limiter that transmits rotation in both left and right rotation directions and has different torque limit values in both rotation directions.

Since the coil spring is engaged with the inner ring in the small diameter portion with a slight interference fit, when the rotation of the inner ring loosens the engagement and rotates in the direction of expanding the diameter of the small diameter portion, the tightening force and the frictional force are balanced. The rotation of the force above the state causes the inner ring to slip, and the torque at that time becomes the set torque limit value in that direction.

On the contrary, when the small diameter portion of the coil spring is rotated in the direction of strengthening the engagement, the diameter of the small diameter portion becomes smaller due to frictional force, but this force is transmitted to the large diameter portion and the diameter of the large diameter portion is reduced. Let The large diameter part engages with the inner diameter of the annulus with a slight interference and rotates with the inner ring, but due to the decrease in the diameter the engagement loosens and the balance between the tightening force and the frictional force is lost Will slip. The torque at this time is the set torque limit value in that direction.

The two set torque limit values are different because the spring constants of the large diameter portion and the small diameter portion are different.

Further, according to the present invention, if the lid member is rotationally adjusted with respect to the outer cylinder member, the set torque limit value can be freely changed. In practice, the set torque limit value can be set to an accurate torque limit value after assembly. You can

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, in the torque limiter of the embodiment, the outer cylinder member 1 is formed with a spring insertion portion 2 inside thereof to be open at one end, and a bearing portion 3 provided at the inner portion thereof. The inner ring 4 is rotatably supported by the inner ring 4, and a coil spring 5 having a different diameter composed of a small diameter portion 5a and a large diameter portion 5b extending in the axial direction is inserted on the outer circumference of the inner ring 4, and is fitted on the other end of the outer tubular member 1. And a lid member 6 that fits and is rotatably fitted on the inner ring 4. Inner ring 4
A notch 7 is provided on the end face of the, and the notch 7 is used for engagement of a pin that connects the inner ring 4 and a shaft inserted inside thereof.

The lid member 6 has an annular portion 6a facing inward, and the annular portion 6a is provided so as to be interposed between the large diameter portion 5b of the coil spring 5 and the inner diameter portion of the outer tubular member 1. Has been. The inner diameter of the small-diameter portion 5a of the coil spring 5 is smaller than the outer diameter of the inner ring 4 in a natural state so that the inner ring 4 has a slight interference fit. The outer diameter of the large-diameter portion 5b is formed to be slightly larger than the inner diameter of the annular portion 6a in a natural state so as to provide a slight interference fit.

Further, as shown in FIGS. 3 and 4, the eccentric curvature portion (in the concentric circle, the outer diameter of the annular portion 6a and the inner diameter of the outer cylinder member 1 at the corresponding portion are concentric with each other at four locations. It is formed to have a radius R). Inside the outer cylinder member 1 of FIG. 3 (a), the annular portion 6a of FIG. 4 (b) is fitted at a corresponding portion of length L.

As shown in FIG. 3 (b), the inner diameter of the outer cylinder member 1 has four curved surfaces centered on a point where the radii of curvature at positions facing each other on the orthogonal axes deviate from the center by an eccentricity δ. It is formed as a series. Therefore, the maximum diameter is D ₁ = (R + δ) × 2, and the minimum diameter is 2 [(R ²
− (Δcos 45 °) ² ) ^1/2 + δcos 45 °] is an eccentric curved surface. As shown in FIG. 4A, the outer diameter of the annular portion 6a is also formed in exactly the same manner. The annular portion 6a is provided with four cutouts 8 at four locations. This is because the inner diameter d of the annular portion 6a can be freely contracted.

In the above embodiment, the eccentric curved surface is set at four places, but at least two places may be provided, and it may be an odd number.

The torque limiter of the embodiment constructed as described above operates as follows. For example, when the inner ring 4 rotates in either the left or right direction, the small diameter portion 5a of the coil spring 5 is set to have an interference fit with the inner ring 4, so that the rotation direction is the direction in which the spring tightening is loosened by frictional engagement. For example, the rotation of the inner ring 4 causes the small-diameter portion 5a to have a larger diameter, and the inner ring 4 slides with respect to the coil spring 5 where the tightening force and the frictional force are balanced. At this time,
The outer diameter of the large-diameter portion 5b is tightly fitted to the inner diameter of the annular portion 6a of the lid member 6, but the large-diameter portion 5b acts in a direction in which the diameter of the large-diameter portion 5b increases due to the frictional force on the small-diameter side. The binding force is further increased with respect to the inside of 6a, and it does not rotate.

On the contrary, when the rotation rotates in the direction of strengthening the spring tightening, it acts on the side where the diameter of the small diameter portion 5a becomes smaller, the tightening force increases, and the coil spring 5 tries to rotate together with the inner ring 4. This rotation is due to the large diameter portion 5b in the coil spring 5.
To act to reduce the diameter of the large diameter portion 5b. The large diameter portion 5b is tightly engaged with the inner diameter of the annular portion 6a, but since the diameter of the large diameter portion 5b is reduced, the frictional engagement force is reduced, and the tightening force and the frictional force of the portion are balanced. The large-diameter portion 5b slides with respect to the annular portion 6a when the collapse occurs.

Therefore, when the inner ring 4 rotates in either direction, the rotation in that direction is interrupted by exceeding the preset torque limit value by the small diameter portion 5a and the large diameter portion 5b that determine the slip in the rotation direction. , As a torque limiter having different torque limit values for both left and right directions.

When the one-way torque limiter which is not used as the torque limiter acting on the rotation in both the left and right directions but idles with the small torque limiter in one direction is used, the tightening force for the inner ring 4 having the inner diameter of the small diameter portion 5a is set. Should be set small in advance.

In the above description, the large diameter portion 5 of the coil spring 5 is
Although it has been described that the diameter of b is constant, the torque limiter of this embodiment can change the diameter of the large diameter portion 5b to easily change the set torque limit value determined by the large diameter portion 5b. It has characteristics.

As described above with reference to FIGS. 3 and 4, the outer diameter of the annular portion 6a and the inner diameter of the outer cylindrical member 1 corresponding to the outer diameter are four eccentrics centered on the point deviated by the eccentricity δ. It has a shape with a series of curved surfaces. The inner diameter of the annular portion 6a is d, which is a perfect circle. Therefore, the annular portion 6a is attached to the outer cylinder member 1
When the state in which the eccentric curved surfaces are fitted to each other is changed by slightly shifting the phase in either the left or right direction, the annular portion 6a receives a force that reduces in the inner diameter direction.
Since the annular portion 6a is provided with the notches 8 at about four places, the inner diameter of the annular portion tends to be small. Therefore, the torque limit value set in the large diameter portion 5b changes due to the reduction of the diameter, and the tightening force for the large diameter portion 5b increases and the set torque limit value also increases.

To change the set torque limit value, the lid member 6 may be rotated with respect to the outer cylinder member 1. In this case, it is assumed that the lid member 6 is fitted to the outer tubular member 1 so strongly that it cannot be easily twisted by hand, but can be rotated by using a proper tool.
Therefore, when assembling the torque limiter of the embodiment, the torque value can be changed with respect to the torque value at the time of assembly, and an extremely accurate torque value can be set.

FIG. 5 shows an example in which the inner ring 4 is omitted and a rotary shaft X is provided instead of the inner ring 4. Since other members are the same, the same reference numerals are given and the description thereof will be omitted. In this embodiment, the size can be further reduced by omitting the inner ring 4.

[0031]

As described above in detail, in the torque limiter according to the present invention, the inner ring is axially supported in the outer cylinder member, and the coil spring having the small diameter portion and the large diameter portion is wound around the outer circumference of the outer ring member to wind the gap between the large diameter portion and the outer cylinder member. It is composed of a lid member with an annular portion to be inserted into the inner ring, and the small diameter portion is slightly interference fit with the inner ring and the large diameter portion with the inner diameter of the annular portion, and the outer diameter of the annular portion and the corresponding Since the inner surface of the outer cylinder member has an eccentric curvature surface at least at two or more locations on the concentric circle, a torque limiter having different torque limit values for both left and right rotation directions can be obtained, and the lid member can be used as the outer cylinder. It is extremely remarkable that the diameter of the ring part can be reduced and the set torque limit value can be changed by rotating it with respect to the member, and this function can be configured with a small number of parts to provide a small and inexpensive product to the market. Na Results can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a torque limiter according to an embodiment.

FIG. 2 is an exploded perspective view of the above.

FIG. 3 is a cross-sectional view of the outer cylinder member and its line III-III.

FIG. 4 is a sectional view of the lid member and its line IV-IV.

FIG. 5 is a sectional view of an embodiment in which an inner ring is omitted.

FIG. 6 is a sectional view of a conventional torque limiter.

[Explanation of symbols]

 1 Outer cylinder member 2 Spring insertion part 3 Bearing part 4 Inner ring 5 Coil spring 5a Small diameter part 5b Large diameter part 6 Lid member 6a Annular part 7 Notch part 8 Notch part

Claims (2)

[Claims] 1. An outer cylinder member, an inner ring rotatably rotatably supported inside thereof, a coil spring of a different diameter including a small diameter portion and a large diameter portion which are incorporated in the outer periphery thereof and extend in the axial direction, and an outer cylinder member. And a lid member that is fitted to the other end and is rotatably fitted onto the inner ring.The small diameter portion of the coil spring is set to have a slight interference fit with the outer diameter of the inner ring, and the lid member moves inward. It has an annular portion facing it, and this annular portion is interposed between the large diameter portion of the coil spring and the inner diameter of the outer cylinder member, and the outer diameter of the large diameter portion is a slight interference fit with respect to the inner diameter of the annular portion. A torque limiter configured to have an eccentric curvature surface at least at two or more locations on a concentric circle where the outer diameter of the annular portion and the inner diameter of the outer cylindrical member at a portion corresponding thereto are provided. 2. The torque limiter according to claim 1, wherein a notch is provided at an appropriate position on the annular portion.