JPH0643545Y2 - Torque limiter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention applies a rotational torque on the input side to the output side via magnetic powder magnetized by a permanent magnet, and a load for shearing the magnetic powder is applied. The present invention relates to a torque limiter that cuts off the transmission of rotational torque when it acts on the output side.

[Conventional technology]

As a conventional torque limiter of this kind, Jikkaku Sho 62
What is disclosed in the publication No. -46016 is typical,
For example, it is widely used in a paper feeding mechanism of a copying machine. This type of torque limiter is provided with, for example, a rotary shaft support whose both ends are supported by the paper feed mechanism via bearings, and a boss made of a magnetic material as an inner pole member fitted and fixed on the rotary shaft. A plurality of permanent magnets are radially fitted and fixed to the outer peripheral recess of the boss while alternately changing their magnetism.
On both sides of the permanent magnet, a pair of non-magnetic material holders,
Of the boss and the permanent magnet, only the outer side in the radial direction of the permanent magnet is exposed to the outside to be in close contact, and a pair of non-magnetic members supported on the rotation shaft support so as to rotate freely on both sides of the holder. A material side cover is provided. Further, a magnetic material case as an outer pole member formed in a concentric cylindrical shape with the side cover is fitted and fixed to the outer side of the side cover with a predetermined gap between the side cover and the outer side in the radial direction of the permanent magnet. The magnetic powder is enclosed in the gap.

With this configuration, when the rotating shaft rotates, the case magnetically coupled through the magnetic powder magnetized by the permanent magnet rotates. Will be sent. When the rotary shaft stops from this state, the paper feed roller stops without overrun. Further, when a load larger than a predetermined amount is applied to the case during rotation such as paper jam, the magnetic powder magnetized by the permanent magnet is sheared, so that the rotation shaft idles and the case is stopped. As a result, when trying to pull out the jammed paper, the pulling force shears the magnetic powder in the opposite direction.

[Problems to be solved by the device]

However, when the magnetic powder is sealed in such a conventional torque limiter, a pair of side covers are fitted to the inner peripheral surfaces of both ends of the case and fixed by an adhesive. If it flows into the gap for powder encapsulation, a part of the magnetic powder will solidify, and stable operation characteristics will not be obtained, and the encapsulation work will be difficult and the workability will be poor, and the work will take a long time. Therefore, there was a problem that productivity was lowered.

The present invention has been made in view of the above points, and an object of the present invention is to provide a torque limiter which is easy to enclose magnetic powder and has good productivity.

[Means for Solving the Problems]

In order to achieve such an object, the torque limiter according to the present invention is a cylindrical magnetic material case for enclosing magnetic powder magnetized by the permanent magnet between the permanent magnet provided on the rotating shaft. And a pair of side covers which are formed in a disk shape by a resin material and which rotatably support the rotation shaft in the central hole and are fixedly assembled in the case opening, and these side covers are provided in the case opening. An elastic retainer locking portion that is engaged with the retainer locked portion provided from the inside, and a retainer engaged with the retainer engaging portion provided in the opening of the case. And an engaging portion.

[Action]

According to the present invention, the rotational torque on the input side is transmitted to the output side through the magnetic powder magnetized by the permanent magnet, and when the load that shears the magnetic powder acts on the output side, the rotational torque is transmitted. Be cut off.

Further, according to the present invention, when enclosing the magnetic powder, one side cover is press-fitted into one end of the cylindrical case to be engaged and engaged to be assembled and fixed, and the permanent magnet and the inner peripheral surface of the case. After inserting the magnetic powder between the two, the other side cover is press-fitted and fixed by assembling and engaging, and the case and both side covers are integrated by engaging and engaging, and the torque limiter The inside and outside are closed and the magnetic powder is enclosed.

〔Example〕

1 to 4 show an example in which the torque limiter according to the present invention is applied to a paper feeding mechanism of a copying machine, and FIG. 1 is a side view showing only the upper half of the torque limiter in a broken view, and FIG. 2 is a sectional view taken along line II-II of FIG. 1, FIG. 3 is an outside front view of the side cover, and FIG. 4 is an inside front view of the same. In the figure,
The torque limiter 1 incorporated in the paper feeding mechanism of the copying machine is
A rotary shaft 2 drivingly connected to the driving side is provided, and a boss 3 as an inner pole member made of a magnetic material is press-fitted and fixed to the knurled uneven outer peripheral surface of the rotary shaft 2. Permanent magnets 4 having different magnetism are alternately fixed to each of the plurality of grooves (six in the present embodiment) formed at positions where the outer peripheral surface of the boss 3 is equally divided in the circumferential direction. A pair of holders 5 made of a resin material are fitted and fixed on both front and rear sides of the boss 3 and the permanent magnet 4 by exposing the magnetic pole surface 4a of the permanent magnet 4 to the outside.

6 is a case formed of a magnetic material in a cylindrical shape,
Both ends of the holder 5 are supported by a pair of side covers 7 which are located on the front and rear sides of the holder 5 and which are fitted into the rotary shaft support 2 so as to rotate freely. They are arranged concentrically with the rotary shaft support 2 with a gap shown by reference symbol S in the drawing.

The side cover 7 is made of a resin material and has a disk shape, and has a central hole 8 that serves as a bearing surface of the rotating shaft 2. The side cover 7 is fixed to the rotating shaft 2 inside the inner peripheral portion thereof. An annular seal portion 9 is integrally formed with the outer surface of the holder 5 to face each other with a minute gap. Also, the side cover 7
A pair of rectangular protrusions 11 fitted and fixed in the groove of the gear 10 which is fitted to the rotating shaft 2 so as to rotate freely are integrally formed on the outer surface of the gear 10, and the gear 10 is rotated integrally with the side cover 7. Is configured to let. On the outer periphery of the side cover 7,
An annular flange portion 12 for axially positioning the side cover 7 by abutting on the opening end surface of the case 6 is integrally formed, and elasticity is provided at a location where the flange portion 12 is divided into two in the circumferential direction. A pair of locking pieces 13 serving as locking portions for locking that are fitted into through holes 6a provided in the case 6 are provided in a protruding manner. The locking piece 13 is integrally formed with the bending portion 13a and the claw portion 13b, and the side cover 7 has the bending portion 13a.
While being elastically deformed, the case 6 is press-fitted into an opening serving as a locked portion for retaining, and the claw portion 13b is engaged with the through hole 6a so as to be retained and fixed. Reference numeral 14 denotes a pair of protrusions, which are anti-rotation engaging portions protrudingly provided at positions that divide the flange portion 12 of the side cover 7 into two in the circumferential direction, and are formed on the opening end of the case 6. The side cover 7 is aligned and fixed in the circumferential direction by being fitted into a groove that serves as a stopped engaged portion.

A gap S between the magnetic pole surface 4a of the permanent magnet 4 and the case 6
A magnetic powder 15 is filled in the inside, and is magnetized by the magnetic flux of the permanent magnet 4 shown by the symbol Φ in the figure.

The operation of the torque limiter configured as above will be described. When the rotary shaft 2 rotates, the case 6 magnetically coupled through the magnetic powder 15 magnetized by the permanent magnet 4 rotates, and the side cover 7 which is prevented from rotating by the protrusion 14 rotates on the case 6. The engagement of the protrusion 11 rotates the output side gear 10. When the rotary shaft 2 stops from this state, the gear 10 stops without overrun. Further, when a load larger than a predetermined amount is applied to the gear 10 due to paper jam during rotation, the magnetic powder 15 magnetized by the permanent magnet 4 is sheared, so that the rotating shaft 2 idles and the transmission of the rotating torque is interrupted. It

When assembling the torque limiter 1 that operates in this manner, the side cover 7 is pushed into the case 6 by pushing one side cover 7 while elastically deforming the locking piece 13 engaged in the through hole 6a of the case 6. And the opening of the case 6 is closed. At this time, the side cover 7 has the protrusion 11
Is positioned in the circumferential direction by engaging with the groove of the gear 10, and is positioned in the axial direction by bringing the flange portion 12 into contact with the opening end surface of the case 6, and
The claw portion 13b of the locking piece 13 elastically engages with the through hole 6a, and the projection 1
Since 4 is fitted in the groove formed at the open end of the case 6 so as not to rotate, the side cover 7 is fixed to the case 6 so as not to rotate and to prevent it from coming off. In this way, one side cover 7 is press-fitted and fixed by assembling by fixing the locking piece 13 that serves as a retaining portion and the protrusion 14 that serves as a rotation-preventing engaging portion, and then, in the gap S. The magnetic powder 15 is filled by filling it with the magnetic powder 15, press-fitting the other side cover 7 in the same manner as described above, and assembling and fixing it by engaging the projection 14 that serves as a retaining engagement portion. However, since the seal portion 9 is provided, the magnetic powder 15 does not leak to the central hole 8 side.

In the present embodiment, as an example of a retaining structure for engaging and fixing the side cover 7, the flexible portion 13a of the retaining piece 13 is elastically deformed to engage the claw portion 13b with the through hole 6a. As shown, a hole is formed in the flexible portion 13a instead of the claw portion 13b, and a through hole is formed.
Instead of 6a, the side cover 7 may be press-fitted and fixed by engaging a convex portion pressed against the case 6 side with this hole.

In this embodiment, as the fitting structure of the side cover 7 and the gear 10, the example in which the protrusion 11 is provided on the side cover 7 side is shown, but the protrusion is provided on the gear 10 side to form the groove on the side cover 7 side. You may make it engage. Furthermore, the side cover 7
Since both and the gear 10 are made of the same resin material, the one side cover 7 and the gear 10 may be integrally formed. In this case, the case 6 has only the opening on the other side of the side cover 7
You can close it with.

[Effect of device]

As described above, according to the torque limiter of the present invention, the cylindrical magnetic material case for enclosing the magnetic powder, the disk-shaped case made of the resin material, and the center hole supporting the rotary shaft are provided. Equipped with a pair of side covers that are assembled and fixed to the case opening, and these side covers have elastic retaining locks that are attached from inside to the retaining locks provided in the case opening. And a detent engagement portion to be engaged with the detent engagement portion provided in the case opening, the following practical use is achieved despite the simple configuration. It has various excellent effects.

That is, according to the present invention, when enclosing the magnetic powder, the side cover fixing work with an adhesive as in the past is eliminated, and the side cover is pressed to assemble, the locking portion for retaining, the rotation stopper Since it suffices to engage and engage the vehicle engaging portion, workability is improved, productivity is improved by shortening work time, and an inexpensive torque limiter can be provided.

Further, unlike the conventional case, the operating characteristics are not deteriorated due to the leakage of the adhesive to the magnetic powder side, and a torque limiter with high quality can be obtained.

[Brief description of drawings]

1 to 4 show an embodiment of a torque limiter according to the present invention, FIG. 1 is a side view showing only an upper half of the torque limiter, and FIG. 2 is a sectional view taken along line II-II of FIG. 3 is an outer front view of the side cover, and FIG. 4 is an inner front view of the same. 1 ... Torque limiter, 2 ... Rotating shaft, 4 ... Permanent magnet, 6 ... Case, 6a ... Through hole, 7 ... Side cover, 8 ... Center hole, 13 ... Locking piece, 13a ... … Bending piece, 13b
…… Claws, 15 …… Magnetic powder, S …… Gap.

Claims (1)

[Scope of utility model registration request] 1. A torque limiter in which a permanent magnet and magnetic powder magnetized by the permanent magnet are disposed between a rotary shaft and an inner peripheral surface of a cylindrical magnetic material case, and a circle is formed by a resin material. A pair of side covers that are formed in a plate shape and that support the rotation shaft through a central hole and that are assembled and fixed to the opening of the cylindrical magnetic material case are provided with these side covers. Elastic locking portion that is engaged from the inside with the locking portion that is provided on the locking portion, and a rotation that is engaged with the locking engagement portion that is provided on the opening of the case. A torque limiter, which is provided with a locking engagement portion.