JP2865440B2 - Torque limiter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a magnetic powder is sealed in a gap formed in a magnetic circuit of a permanent magnet, and rotation of an input side is transmitted to an output side through a magnetic powder magnetized by the permanent magnet. The present invention relates to a torque limiter that blocks transmission of rotational torque when a load for shearing magnetic powder acts on the output side.

[0002]

2. Description of the Related Art Conventionally, as this type of torque limiter, for example, a torque limiter disclosed in Japanese Utility Model Laid-Open No. 63-104729 is known. In this torque limiter, a permanent magnet is fitted and fixed on a rotating shaft made of a resin material. Similarly, on this rotating shaft, a pair of resin-made side surfaces having cylindrical bosses abutting on both end surfaces of the permanent magnet are provided. A cover is rotatably fitted by connecting the outer peripheral portions with a cylindrical case, and magnetic powder is sealed between the permanent magnet and the case. Further, the joint between the side cover and the cylindrical case has a structure in which the side cover is fitted into the opening end of the cylindrical case and fixed with an adhesive.

[0003] With this configuration, when the case rotates, the rotating shaft that is magnetically coupled via the magnetic powder magnetized by the permanent magnet rotates, and during rotation, the rotating shaft is larger than a predetermined size. When a load is applied, the magnetic powder magnetized by the permanent magnet is sheared, so that the case spins and the rotating shaft stops.

[0004]

However, with such a structure in which the resin side covers are fitted and fixed to both ends of the case, the side covers are fixed to one of the cylindrical cases as a setup before assembly. Not only is it difficult to manufacture, but also when the other side cover is fixed to the other end of the cylindrical case after enclosing the magnetic powder, the adhesive for this fixing enters the case. The magnetic powder can be agglomerated, and the operating characteristics of the torque limiter are likely to deteriorate.
That is, the conventional torque limiter has low productivity and low reliability.

[0005]

A torque limiter according to a first aspect of the present invention covers an outer periphery of a cylindrical case with a resin, and ultrasonically welds a resin located at an opening of the cylindrical case to a side cover. is there.

In a torque limiter according to a second aspect of the present invention, an outer periphery of a cylindrical case is covered with a resin, and a protrusion penetrating a side cover is integrally formed with a resin portion located at an opening of the cylindrical case. The side cover is fixed to the cylindrical case by thermally deforming a portion of the projection that protrudes from the side cover.

[0007]

[Advantage] When the side cover is attached to the cylindrical case, no adhesive is required.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 is a sectional view of a torque limiter according to the present invention, and FIG. 2 is an enlarged sectional view showing a main part of the torque limiter according to the present invention. In these figures,
Reference numeral 1 denotes a torque limiter mounted on a paper feeder of a copying machine. This torque limiter 1 has a sleeve shaft 2 as a rotary shaft formed of a synthetic resin material in a cylindrical shape. The sleeve shaft 2 is fitted on a rotary shaft 3 provided in a paper feeder of a copying machine. Have been combined. The sleeve shaft 2 is connected to a gear 4 fixed to the rotating shaft 3 via an engaging portion including a projection 2a and a concave portion 4a, and is thereby prevented from rotating with respect to the rotating shaft 3. On the sleeve shaft 2, a pair of permanent magnets 5a, 5b formed in an annular shape and magnetized in the axial direction are fixed to the magnetic plates 6a, 6b and 6 as inner magnetic members.
c, 6d and fixed.
The protrusions of the disc-shaped flange 2b as spacers formed on the sleeve shaft 2 are engaged with the openings formed in the sleeve shaft 2 to 6d. The permanent magnets 5a and 5b are integrally insert-molded with the sleeve shaft 2 and the magnetic plates 6a to 6d. Reference numeral 7 denotes a cylindrical collar made of a non-magnetic material fitted to the outer peripheral surface of each of the permanent magnets 5a and 5b.

On the sleeve shaft 2, there are side covers 8, 9 adjacent to the outer disk-shaped flanges 2b, respectively.
A case assembly 11 integrally formed with a case 10 whose both ends are supported by these side covers 8 and 9 is rotatably provided. One side cover 8 constituting the case assembly 11 is formed of a synthetic resin material in an annular shape having an L-shaped cross section, and is rotatably fitted to the sleeve shaft 2. 8a is cut off. A case 1 formed of a magnetic material into a cylindrical shape is provided on the inner peripheral side of the cylindrical portion of the side cover 8.
0 is insert molded. The case 10 is embedded in the side cover 8 so that one end of the case 10 is
, And the entire outer peripheral surface is covered with the resin. The case 1 in the side cover 8
A portion located at the opening end of the opening 0, in other words, on the outer peripheral side of the opening edge of the cylindrical portion, is provided with a welded portion 8b formed thinner than other portions. The other side cover 9 constituting the case assembly 11 is formed in a substantially annular plate shape from a synthetic resin material, and is rotatably fitted to the sleeve shaft 2. It is ultrasonically welded and fixed to the shape part over the entire circumference. The welded portion between the side cover 9 and the cylindrical portion of the side cover 8 is configured as shown in FIG. That is, a circular groove 9a into which the cylindrical portion of the side cover 8 is fitted is formed in the outer peripheral portion of the side cover 9 so as to open to the side, and the outer peripheral wall surface 9b of the circular groove 9a The weld 8b is in contact. Ultrasonic welding is performed by bringing the sound pole of an ultrasonic welding machine (not shown) into pressure contact with the outer peripheral surface of the side cover 9 in such a state, and welding the outer peripheral wall surface 9b and the outer peripheral surface of the welded portion 8b. Will be

Numeral 12 is a weight reducing concave hole, which is formed in an arc shape on the outer end surfaces of both side covers 8 and 9.
Reference numeral 13 denotes a magnetic powder magnetized by the permanent magnets 5a and 5b, and the magnetic powder 13 is sealed in an annular space between the inner peripheral surface of the case 10 and the magnetic plates 6a to 6d. .

The operation of the torque limiter configured as described above will be described. The magnetic flux of the permanent magnets 5a and 5b flows through the permanent magnets 5a and 5b → the magnetic plates 6a to 6d → the magnetic powder 13 → the case 10 → the magnetic powder 13 → the magnetic plates 6a to 6d as a magnetic circuit. Plates 6a to 6d and case 10
When the motor of the copier rotates, the rotation is transmitted to the teeth 8a along the path of the rotating shaft 3, the torque limiter 1, and the teeth 8a. Sent to the body.

If the load on the teeth 8a becomes larger than a predetermined load due to two copy sheets being fed or the paper being jammed, the teeth 8a are braked by the overload, and the magnetic powder in the torque limiter 1 is damaged. Since the body 13 is sheared, the rotating shaft 3 idles and the case 10 is stopped.

Next, a procedure for assembling the torque limiter 1 will be described. The sleeve shaft assembly is integrally insert-molded with the permanent magnets 5a, 5b and the magnetic plates 6a to 6d sandwiched between the flange portions 2b of the sleeve shaft 2, and the case 10 is held on the side cover 8. In this state, the side cover 8 is integrally insert-molded. Then, the side cover 8 is rotatably fitted to the sleeve shaft 2 of the sleeve shaft assembly, and the magnetic powder 13 is sealed in a gap in contact with the inner peripheral surface of the case 10. Is ultrasonically welded to the side cover 9 to integrate the two side covers 8 and 9 together. In performing the ultrasonic welding, the welding portion 8b of the side cover 8 is fitted into the circular groove 9a of the side cover 9 as described above. Thus, both side covers 8,
9 is ultrasonically welded, and the assembling operation is completed.

Therefore, in the torque limiter 1 configured as described above, no adhesive is required to attach the side cover 9 to the cylindrical case 10, so that the assembling operation is simplified and the adhesion in the case is prevented. The agent does not harden the magnetic powder 13.

In the above-described embodiment, an example is shown in which the welded portion 8b of the side cover 8 is brought into surface contact with the circular groove 9a of the side cover 9 and the contact surfaces are ultrasonically welded. As described above, a space can be provided in the welded portion. FIG. 3 is a sectional view showing another embodiment in which a circumferential wall of a groove into which a cylindrical portion is fitted is inclined to provide a gap in a welded portion, and FIG. 4 is a chamfered front peripheral edge of a disk fitted into a circular concave portion. It is sectional drawing which shows the other Example which provided the clearance gap in the welding part. In these figures, the same or equivalent members as those described in FIG. 1 and FIG. 2 are denoted by the same reference numerals, and detailed description is omitted. 3 and 4, reference symbol S denotes an annular gap provided in the welded portion, and this gap S is formed by inclining the outer peripheral wall 9b of the circular groove 9a in the side cover 9 in the example shown in FIG. ing. Further, in the example shown in FIG. 4, the structure of the welded portion is different from the above-described example, and the disk portion 22 of the side cover 9 is fitted into the circular recess 21 formed in the end face of the side cover 8. Have been. The gap S is defined by the disc portion 2
2 is formed in the welded portion by chamfering the fitting side peripheral edge. With such a structure in which the gap S is provided in the welded portion, the burrs do not project on the surface of the case assembly 11 during welding.

Next, the torque limiter according to the second invention will be described in detail with reference to FIG. FIG. 5 is an enlarged sectional view showing a main part of the torque limiter according to the second invention. In the figure, the same or equivalent members as those described in FIG. 1 and FIG. 2 are denoted by the same reference numerals, and detailed description is omitted. In FIG. 5, reference numeral 31 denotes a protrusion for fixing the side cover 9 to the side cover 8;
Is formed integrally with the tip of the tubular portion of the side cover 8 and protrudes along the extending direction of the tubular portion. The projection 31 shown in FIG. 5 shows a state after the side cover is assembled, and is formed as shown by a two-dot chain line before the assembly.
A side cover 9 coupled to the side cover 8
In the present embodiment, a circular convex portion 32 fitted into the cylindrical portion of the side cover 8 and a through hole 3 through which the protrusion 31 is inserted are provided.
3 are formed. The through hole 33 is formed in the outer peripheral portion of the side cover 9, and a portion of the through hole 33 on the side cover 8 side has a hole diameter with which the projection 31 is fitted.
The portion opposite to the side cover 8 is formed with a sufficiently larger hole diameter than the projection 31.

The two side covers 8 configured as described above,
First, in order to join together, the protrusion 31 is inserted into the through hole 3.
3 to temporarily assemble both side covers 8 and 9. Thereafter, the sound pole of an ultrasonic welding machine (not shown) is pressed against the tip of the projection 31 to apply ultrasonic vibration to the projection 31. Then, the side cover 9 can be fixed to the side cover 8 by thermally deforming the projection 31 by ultrasonic vibration as shown by a solid line in FIG. Therefore, even with this configuration, the case assembly can be assembled without using an adhesive, so that the assembling work is simplified and the magnetic powder is hardened by the adhesive contained in the case. Disappears.

In each of the above-described embodiments, the case 10 is inserted into one side cover (side cover 8) to form a pair. However, both the case and the pair of side covers may be ultrasonically welded. Further, in the first and second inventions, the shape of the side cover, the shape of the sleeve shaft, the structure in which a magnetic plate or a permanent magnet is insert-molded on the sleeve shaft, and the permanent magnet magnetized in the axial direction are configured. Is not particularly limited. further,
In each of the above-described embodiments, the example in which the torque limiter is provided in the paper feeder of the copying machine has been described. However, the torque limiter can be used as a load brake of a facsimile.

[0019]

As described above, the torque limiter according to the first aspect of the invention covers the outer periphery of the cylindrical case with resin, and ultrasonically welds the resin located at the opening of the cylindrical case to the side cover. In the torque limiter according to the second invention, the outer periphery of the cylindrical case is covered with a resin, and a protrusion penetrating the side cover is integrally formed with a resin portion located at an opening of the cylindrical case. Since the side cover is fixed to the cylindrical case by thermally deforming a portion of the projection protruding from the side cover, no adhesive is required to attach the side cover to the cylindrical case. For this reason, the assembling operation is simplified, and the magnetic powder is not hardened by the adhesive entering the case during the assembling. Therefore,
It is possible to obtain a highly reliable torque limiter that improves productivity and does not change its operation characteristics after assembly. Further, since the outer periphery of the cylindrical case is covered with the resin, there is no need to apply a rust preventive to the outer peripheral surface of the case, so that the productivity can be improved from this point as well.

[Brief description of the drawings]

FIG. 1 is a sectional view of a torque limiter according to the present invention.

FIG. 2 is an enlarged sectional view showing a main part of the torque limiter according to the present invention.

FIG. 3 is a cross-sectional view showing another embodiment in which a circumferential wall of a groove into which a cylindrical portion is fitted is inclined to provide a gap in a welded portion.

FIG. 4 is a sectional view showing another embodiment in which a front peripheral edge of a disk fitted into a circular recess is chamfered to provide a gap in a welded portion.

FIG. 5 is an enlarged sectional view showing a main part of a torque limiter according to a second invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Torque limiter 2 Sleeve shaft 5a Permanent magnet 5b Permanent magnet 8 Side cover 9 Side cover 10 Case 13 Magnetic powder 31 Projector 33 Through hole

Continuation of the front page (56) References JP-A-63-47523 (JP, A) JP-A-4-50513 (JP, A) JP-A-61-211970 (JP, A) JP-A-3-7535 (JP) , U) Japanese Utility Model Hei 3-48808 (JP, U) Japanese Utility Model Utility Model 63-1424 (JP, U) Japanese Utility Model Utility Model 62-12909 (JP, U) Japanese Utility Model Utility Model 61-140482 (JP, U) (58) Field surveyed (Int.Cl. ⁶ , DB name) F16D 7/02 F16D 37/02

Claims (2)

(57) [Claims] 1. A cylindrical case made of a magnetic material, both ends of which are supported by a pair of resin side covers, and a rotating shaft penetrating a central portion of the cylindrical case, and an inner peripheral surface of the cylindrical case. In a torque limiter in which a permanent magnet and a magnetic powder magnetized by the permanent magnet are arranged between the cylindrical case and the rotating shaft, the outer periphery of the cylindrical case is covered with a resin, and is located at an opening of the cylindrical case. Torque limiter characterized by ultrasonic welding of resin to side cover. 2. A cylindrical case made of a magnetic material, both ends of which are supported by a pair of resin side covers, and a rotating shaft penetrating a central portion of the cylindrical case, and an inner peripheral surface of the cylindrical case. And a torque limiter in which a permanent magnet and a magnetic powder magnetized by the permanent magnet are disposed between the rotating shaft and the rotating shaft, while covering an outer periphery of the cylindrical case with a resin,
A protrusion that penetrates the side cover is integrally formed with the resin portion located at the opening of the cylindrical case, and the portion of the protrusion protruding from the side cover is thermally deformed to fix the side cover to the cylindrical case. A torque limiter characterized by: