JP4596502B2 - Bidirectional torque limiter - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a bidirectional torque limiter, and more particularly to a bidirectional torque limiter used in a paper feed path of a printer, a copying machine, or the like, in which a forward torque value and a reverse torque value are set independently. The present invention relates to a bidirectional torque limiter that can be used.
[0002]
[Prior art]
As a conventional bidirectional torque limiter, for example, there is one having the structure of the invention disclosed in Japanese Patent Laid-Open No. 5-87155. That is, it is composed of a spring seat ring, a C-shaped ring spring, a coil spring and an outer ring, the C-shaped ring spring is loosely fitted to the torque transmission shaft of the spring seat ring, and the coil spring is wound around the outer diameter surface of the spring seat ring and the C-shaped ring spring. The outer ring is fitted to the outside of the coil spring, the outer ring is fixed to the spring seat ring, one end of the coil spring is engaged with the spring seat ring, and the other end is engaged with the outer ring to transmit torque to the C-shaped ring spring. A forward / reverse rotational torque limiter with the members engaged is shown.
[0003]
Also, there is a structure disclosed in Japanese Patent Application Laid-Open No. 9-53649 related to a patent application by the same person as the present applicant. That is, a first inner ring and a second inner ring that are coaxial with each other and disposed in the thrust direction, and an outer ring that encompasses the outside of the first inner ring and the second inner ring, and one end of the second inner ring. The outer ring with which the coil is fitted, the coil spring wound around the outer periphery of the first inner ring, the coil spring on the outer periphery of the second inner ring wound in the opposite direction to the coil spring, and the radial torque of each end of these coil springs There has been proposed a bidirectional torque limiter composed of connecting means.
[0004]
Further, there is a structure disclosed in Japanese Patent Laid-Open No. 9-166153 relating to the invention for which a patent application has been made by the same applicant as the present applicant. That is, the inner cylinder, the outer cylinder positioned outside the inner cylinder, the shield positioned outside the inner cylinder, and the first coil wound between the outer surface of the inner cylinder and the inner surface of the outer cylinder and wound around the outer surface of the inner cylinder And a second coil portion that is between the outer surface of the inner cylinder and the inner surface of the shield and is wound around the outer surface of the inner cylinder in a direction opposite to the first coil portion. Bidirectional rotational torque that is locked to the cylinder and transmitted from the outside to the outer cylinder through a shield is limited by sliding between the outer surface of the inner cylinder and the first coil portion or the second coil portion. A bidirectional torque limiter has been proposed.
[0005]
However, in such a conventional bidirectional torque limiter, the first one has a simple structure, but the torque value in the forward direction and the torque value in the reverse direction are substantially the same, and the second Although it is possible to independently set the torque value in the forward direction and the torque value in the reverse direction, there is a problem that the structure is considerably complicated. The third one is free and independent in setting the torque value in the forward direction and the reverse direction. However, since the shield also serves as an element for torque transmission, it cannot be said that there is not necessarily a manufacturing restriction condition. .
[0006]
[Problems to be solved by the invention]
It is an object of the present invention to obtain a bidirectional torque limiter having a simple structure that is easy to manufacture and enables the torque value in the forward direction and the torque value in the reverse direction to be set independently in the bidirectional torque limiter.
[0007]
[Means for Solving the Problems]
In order to solve this problem, the present invention proposes the following means as the first means. An inner ring having an outer peripheral surface and both end portions; a first coil spring wound around the outer peripheral surface of the inner ring with an interference fit, the first coil spring having a locking portion at one end thereof; and the inner ring A second coil spring wound around the outer periphery of the second coil spring, the second coil spring being wound in the opposite direction to the first coil spring and having a locking portion at one end thereof; cylindrical shape An outer ring, a fitting portion that fits into one end of the inner ring, an inner peripheral surface, and an engagement that is provided on the inner peripheral surface and locks the locking portion of the first coil spring. An outer ring having a portion and an opening; a side ring, a cylindrical portion, a flange portion, a locking portion for locking the locking portion of the second coil spring provided on the flange portion, and the inner ring A side ring having a fitting portion fitted to the other end; and a seal A is, together with supporting the outer periphery of the side wheel, and a shield which fits into the opening of the outer ring; a bidirectional torque limiter composed of, in the outer ring and the side wheels, respectively, of which An inner ring that encloses the one end portion and the other end portion of the inner ring that are rotatably fitted by a fitting portion and that reinforces the inner periphery of the inner ring is provided. A bidirectional torque limiter is proposed.

[0008]
As a second means, it is proposed to provide a spacer between the first coil spring and the second coil spring.
[0009]
As a third means, it is proposed that the outer ring, the inner ring, and the side ring have holes that penetrate uniformly.
[0010]
As a fourth means, the side ring is provided with a local ring for sealing and reinforcing the contact portion with the outer ring in the flange portion, and the outer ring has a local ring groove corresponding to the local ring. 4. The bidirectional torque limiter according to claim 1, wherein the bidirectional torque limiter is provided on a peripheral surface .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an exploded side view of an embodiment of a bidirectional torque limiter according to the present invention, and FIG. 2 is an axial sectional view of the embodiment of the bidirectional torque limiter according to the present invention. Hereinafter, an embodiment of a bidirectional torque limiter according to the present invention will be described with reference to FIGS. The bidirectional torque limiter 10 includes an outer ring 1 of one torque transmission unit, an inner ring 2 positioned on the innermost side, a side wheel 3 of another torque transmission unit, a coil spring 4 wound around the inner ring 2, and a coil spring. 5, a spacer 6, and a shield 7, which are arranged at concentric positions. The outer ring 1 wraps almost the whole and is closed by the shield 7.
[0012]
The outer ring 1 has a cylindrical shape made of polyacetal resin, and has a large inner cylindrical surface 13 at the center, an opening 17 at one end, and a lid 11 at the other end. The lid portion 11 is provided with two keys 18 symmetrically about the center for transmitting torque to the outside. A circular edge 12 is provided inside the lid portion 11. The inner cylindrical surface 13 is provided with a wall groove 14 that extends uniformly in the axial direction. The inner cylindrical surface 13 is provided with a plurality of wall grooves 19 extending uniformly in the axial direction at other circumferential angles, and is provided for collecting lubricating grease (not shown).
[0013]
The inner ring 2 has a cylindrical shape made of steel, and includes a cylindrical peripheral portion 24, an end portion 21, and another end portion 23, and has a size stored inside the outer ring 1. The end 21 is dimensioned to fit in the circular groove 12 of the outer ring 1 so as to be slidable.
[0014]
The side wheel 3 has a cylindrical shape made of polyacetal resin, and is provided with a flange portion 31 and a cylindrical portion 37. The outer periphery of the flange portion 31 has a dimensional shape inscribed in the inner ring surface 13 of the outer ring 1 so as to be rotatable. Further, the flange portion 31 is provided with a circular edge 32, and the circular edge 32 has a dimensional shape that fits rotatably on the end portion 23 of the inner ring 2. Further, the flange portion 31 is provided with a wall groove 35 in the axial direction, and the wall groove 35 has a shape and dimension for locking the protrusion 55 of the coil spring 5. A key groove 39 for transmitting torque is provided at the end of the cylindrical portion 37.
[0015]
The coil spring 4 is made of a steel wire for a spring and is wound around the cylindrical peripheral portion 24 of the inner ring 2 with an interference fit. A protrusion 44 protruding in the radial direction is provided at a position near the end 21 of the inner ring 2. The coil spring 4 is wound counterclockwise from the projection 44, and the other end is opened.
[0016]
The coil spring 5 has the same material and winding method as the coil spring 4. That is, it is made of spring steel wire and is wound around the cylindrical peripheral portion 24 of the inner ring 2 with an interference fit. A protrusion 55 protruding in the axial direction is provided at a position near the end 23 of the inner ring 2. The coil spring 4 is wound clockwise from the protrusion 55, and the other end is opened. The coil spring 5 and the coil spring 4 are wound in opposite directions.
[0017]
The spacer 6 is an annular disk made of polyacetal resin, and is fitted to the cylindrical peripheral portion 24 of the inner ring 2 and disposed at a position separating the coil springs 4 and 5.
[0018]
The shield 7 is an annular disk made of polyacetal resin, and has a flange portion 77 that is press-fitted into the inner wall end groove portion 17 of the outer ring 1, and an inner peripheral portion 73 having a shape and dimension that slides on the cylindrical portion 37 of the side wheel 3. Is provided.
[0019]
The components described above are assembled in the order shown in FIG.
The protrusion 44 of the coil spring 4 is fitted into the wall groove 14 of the outer ring 1 while sliding in the axial direction. The protrusion 55 of the coil spring 5 is fitted into the wall groove 35 of the side wheel 3 while sliding in the axial direction. The end portion 21 of the inner ring 2 is fitted in a circle 12 of the outer ring 1 so as to be rotatable. The end portion 23 of the inner ring 2 is fitted in a circle 32 of the side wheel 3 so as to be able to roll. Then, the bidirectional torque limiter 10 is completed by filling the grease around the coil springs 4 and 5 with grease for lubrication (not shown).
[0020]
FIG. 3 is a radial cross-sectional view of the embodiment of the bidirectional torque limiter according to the present invention, and shows a cross section taken along line AA in FIG. It can be understood that the protrusion 55 of the coil spring 5 is fitted in the locking groove 35 of the side wheel 3 and locked in the radial direction.
[0021]
FIG. 4 is another sectional view in the radial direction of the embodiment of the bidirectional torque limiter according to the present invention, and shows a section taken along line BB in FIG. It can be understood that the projection 44 of the coil spring 4 is fitted in the locking groove 14 of the outer ring 1 and locked in the radial direction.
[0022]
The operation of the bidirectional torque limiter 10 configured as described above will be described. In FIG. 2, the projection 55 of the coil spring 5 is locked to the side wheel 3 in the radial direction, and the projection 44 of the coil spring 4 is locked to the outer ring 1 in the radial direction. Therefore, when a rotational torque is applied to the side wheel 3 in the clockwise direction (see FIG. 2 from the lower side of the drawing), the coil spring 5 is in a loosening direction. When the frictional force acts and attempts to exceed the predetermined torque value, the frictional torque is maintained while maintaining the frictional torque. Further, when the coil spring 4 receives a clockwise rotational torque, the coil spring 4 is in a tightening direction and the protrusion 44 is locked to the outer ring 1, so that the torque is completely transmitted. Therefore, when a rotational torque is applied to the side wheel 3 in the clockwise direction, it acts as a torque limiter for the torque value determined by the coil spring 5.
[0023]
Conversely, when a rotational torque is applied to the side wheel 3 in the counterclockwise direction, the coil spring 5 rotates counterclockwise and the coil spring 5 is tightened, and the torque is completely transmitted to the inner ring 2. Further, when the coil spring 4 receives a counterclockwise rotational torque, the coil spring 4 is subjected to frictional force with the inner ring 2 up to a predetermined torque value. The spring 4 starts to loosen and rotates while maintaining its friction torque. Therefore, when a rotational torque is applied to the side wheel 3 in the counterclockwise direction, it acts as a torque limiter for the torque value determined by the coil spring 4.
[0024]
Since the coil spring 4 and the coil spring 5 can freely and independently determine the spring constant and the like, the bidirectional torque limiter 10 can also independently select the torque values in the forward direction and the reverse direction.
[0025]
FIG. 5 is a sectional view in the axial direction of another embodiment of the bidirectional torque limiter according to the present invention. Regarding the reference numerals of the constituent elements in this embodiment, the same reference numerals as those in the embodiment shown in FIGS. 1 and 2 correspond to the same constituent elements, respectively. The embodiment shown in FIG. 5 is characterized by the shapes of the outer ring 1, the inner ring 2 and the side ring 3, and is filled with lubricating grease (not shown) around the coil springs 4 and 5, such as the grease. Has a sealed reinforced structure that does not leak to the outside. In other words, the inner ring 1n is provided on the outer ring 1, and the inner periphery of the inner ring 2 is hermetically sealed. Similarly, the outer ring 1 is provided with a local ring groove 1m to reinforce the contact portion with the side ring 3. Corresponding to the local ring groove 1m, the side ring 3 is provided with a local ring 3m. The side ring 3 is further provided with an inner ring 3n to seal and strengthen the contact part with the inner ring 2. The operation as the bidirectional torque limiter is the same as that of the embodiment described above.
[0026]
The bidirectional torque limiter described above is an example of an embodiment of the present invention, and can be freely modified within the scope of the gist of the present invention. For example, regarding the constituent materials, the materials described in the embodiment are merely examples, and are not restricted by those materials, and an optimum material can be selected according to the purpose. Moreover, the outer ring | wheel 1, the inner ring | wheel 2, and the side ring | wheel 3 demonstrated by embodiment are not limited to the ring as a name, The center part may also be tight and peeled. However, in practice, the shape in which the shaft is inserted in the center is often more convenient.
[0027]
【The invention's effect】
The present invention has the above-described features, and in the bidirectional torque limiter, the torque value in the forward direction and the torque value in the reverse direction can be set independently, and a bidirectional torque limiter having a simple structure that is easy to manufacture. Obtainable. Easy assembly with coil springs and protrusions. In addition, the shield does not serve as a function that requires critical adjustment, and there are few restrictions on production. Further, it is possible to adopt a structure that enhances the sealing against leakage of internal lubricating grease or the like.
[Brief description of the drawings]
FIG. 1 is an exploded side view of an embodiment of a bidirectional torque limiter according to the present invention.
FIG. 2 is a sectional view in the axial direction of an embodiment of a bidirectional torque limiter according to the present invention.
FIG. 3 is a radial sectional view of an embodiment of a bidirectional torque limiter according to the present invention.
FIG. 4 is another cross-sectional view in the radial direction of the embodiment of the bidirectional torque limiter according to the present invention.
FIG. 5 is a sectional view in the axial direction of another embodiment of the bidirectional torque limiter according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Outer ring 2 ... Inner ring 3 ... Side wheel 4 ... Coil spring 5 ... Coil spring 6 ... Spacer 7 ... Shield 10 ... Bidirectional torque limiter

Claims (4)

An inner ring having an outer peripheral surface and both end portions; a first coil spring wound around the outer peripheral surface of the inner ring with an interference fit, the first coil spring having a locking portion at one end thereof; and the inner ring A second coil spring wound around the outer periphery of the second coil spring, the second coil spring being wound in the opposite direction to the first coil spring and having a locking portion at one end thereof; cylindrical shape An outer ring, a fitting portion that fits into one end of the inner ring, an inner peripheral surface, and an engagement that is provided on the inner peripheral surface and locks the locking portion of the first coil spring. An outer ring having a portion and an opening; a side ring, a cylindrical portion, a flange portion, a locking portion for locking the locking portion of the second coil spring provided on the flange portion, and the inner ring A side ring having a fitting portion fitted to the other end; and a seal A is, together with supporting the outer periphery of the side wheel, and a shield which fits into the opening of the outer ring; a bidirectional torque limiter consisting of,
Each of the outer ring and the side ring includes the one end and the other end of the inner ring that are rotatably fitted by their fitting portions, and the inner circumference of the inner ring is hermetically sealed. A bidirectional torque limiter characterized in that an internal ring is provided.   The bidirectional torque limiter according to claim 1, further comprising a spacer between the first coil spring and the second coil spring.   3. The bidirectional torque limiter according to claim 1, further comprising a hole that penetrates the outer ring, the inner ring, and the side ring uniformly. 4. The side ring is provided with a local ring in the flange portion for sealing and strengthening the contact portion with the outer ring, and the outer ring is provided with a local ring groove on the inner peripheral surface corresponding to the local ring. bidirectional torque limiter of claim 1 through claim 3, characterized in that there.

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