JPH10322978A - Commutator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold commutator which is mechanically extremely stable with respect to centrifugal force at high-speed rotation, in the mold commutator of a commutator motor. SOLUTION: A commutator is made in a structure where a commutator piece 1 of a mold commutator is equipped with cuts 11 and 12d, and the insulators 8 by resin can be made at the same time at the cuts 11 and 12, by performing resin molding. This can be made a mold commutator, which is mechanically extremely stable with less expansion in the commutator piece 1 with respect to the centrifugal force in high-speed rotation, by press-fitting a shrink ring 7 though this insulator 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed commutator for use in an AC commutator motor such as a vacuum cleaner motor.

[0002]

2. Description of the Related Art As a typical commutator mass-produced at present, there is a resin mold commutator.

This is a structure shown in FIG. 8, in which a commutator piece 1 and a boss 3 are molded with a resin 2. As the resin 2, a phenolic resin that can withstand high temperature and centrifugal force is used. FIG. 7 is an enlarged view of a commutator piece. The commutator piece 1 is processed into a shape of the riser 4 at the left end after the resin molding. A magnet wire 6 is connected to the riser 4 and finally electrically welded to complete an armature. The commutator surface 5 is ground to a predetermined external accuracy. The resin mold commutator is rich in mass productivity and inexpensive. However, since all of the mechanical structure is formed by the resin 2, there is a limit in mechanical rigidity such as centrifugal resistance at high speed.

For example, with a commutator having a diameter of 25 mm, the continuous speed that can be practically used is up to about 45,000 RPM.

When the commutator face cannot withstand the above speed, the commutator piece 1 rises up by several μm from the portion where the resin is mechanically fragile, and the brush rises up every time from this, causing a spark discharge, that is, a spark phenomenon. Shorten motor life rapidly.

FIG. 6 is a diagram showing a measurement example of a defective product in which a commutator piece has risen.

[0007]

As described above, in order to prevent the commutator segment 1 from floating in some way even at high speed, a typical method is to shrink the entire commutator segment with the shrink ring 7. There is a way to do that.

FIG. 5 shows a configuration of a commutator using the shrink ring 7. The shrink ring 7 is generally formed by processing a steel material into a ring shape. However, there is no electrical meaning between the shrink ring 7 and the commutator piece 1 unless some insulator 8 is interposed therebetween.

According to the present invention, the insulator 8 is formed industrially at a low cost, and a stable ultra-high-speed commutator is provided by the shrink ring 7.

If the shrink ring 7 is made of carbon fiber or the like, the structure itself is very convenient because it is an insulator itself, but it is expensive.

In the case of a steel shrink ring, a method of insulating the inner diameter of the shrink ring with an insulator, or a method of inserting an insulator 8 between the shrink ring 7 and the commutator 1 in an orthodox, etc. Although it can be considered, the stability is lacking because the shrink ring 7 needs to be press-fitted in the final step.

[0012]

In order to solve the above problems, a commutator according to the present invention has a concave portion on the surface and a commutator piece provided with a riser portion at an end, and the commutator piece is arranged on a side surface. A commutator main body, a shrink ring insulating portion provided in the recess, and a shrink ring press-fitted to the surface of the shrink ring insulating portion. The commutator body and the shrink ring insulating portion are integrated. Since it is a molding resin and the insulation of the shrink ring is stable, the shrink ring can be mounted at a low cost by using a rigid steel ring without any insulation treatment itself.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A commutator according to the present invention has a commutator piece having a concave portion on the surface and a riser portion at an end, a commutator body having the commutator piece disposed on a side surface, and the concave portion. The shrink ring insulating portion disposed in the shrink ring insulating portion, and a shrink ring press-fitted on the surface of the shrink ring insulating portion, the commutator body and the shrink ring insulating portion are formed integrally resin, so that the shrink ring Since the insulation is stable, the shrink ring can be mounted at a low cost by using a rigid steel ring without any need for insulation treatment.

Further, by installing a shrink ring on one side of the riser side of the commutator, the degree of outer diameter expansion is suppressed,
A stable commutator can be provided even at high speed rotation.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, when the shape of the commutator piece 1 is partially deformed and the insulator 8 is resin-molded with the commutator itself, it is simultaneously molded with the resin 2 and formed.

FIG. 4 is a characteristic diagram obtained by actually measuring the degree of expansion of the commutator surface of the conventional resin-molded commutator and the commutator by the shrink ring this time. It goes without saying that the smaller the degree of external expansion, the higher the speed of the commutator. Reference numeral 13 in FIG. 4 is a conventional commutator, which has already exceeded the danger area at 50,000 RPM.

Numeral 16 has shrink rings at both ends, and naturally has the smallest degree of expansion. Reference numeral 15 denotes a shrink ring on the riser side, and reference numeral 14 denotes a shrink ring on the opposite riser side. It should be noted that the effect of the fifteen riser side shrink rings is great. This is because the riser protrudes, so that its GD ² becomes large, and the degree of expansion is increased accordingly.

For this reason, the shrink ring at the riser part suggests that shrinking is more effective. As a result, it is effective and economical to construct a single-sided shrink ring on the riser side.

Hereinafter, embodiments of the present invention will be described.
3A is a side view of a commutator piece, FIG. 3B is a front view,
FIG. 3C is a side view of FIG. 3A viewed from the right side.
The surface of the commutator piece 1 has a notch 11 and a depth of about 0.
5 mm. In addition, there are cuts 12 on both sides of the commutator piece 1 and the depth is about 0.3 mm. The cut length is about 4 mm. FIG. 2 shows a commutator (specification product) obtained by combining the above commutator pieces and molding the resin. As shown in the AA sectional view, the surface of the commutator piece 1 is covered with a finished resin 8 and is ready to press-fit a steel shrink ring. FIG. 1 is a completed view of the commutator in which the shrink ring 7 has been press-fitted into the cut upper surfaces 11 and 12 of the commutator piece 1 and the processing of the riser portion has been completed. The shrink ring 7 is a steel ring which is press-fitted to the finished outer shape of the commutator by means of a press fit. Depending on the model, the shrink ring 7 may be press-fitted after being heated to about 300 ° C.

[0020]

As described above, according to the invention of claim 1 of the present application, a shrink ring is formed in the vicinity of the riser, which is vulnerable to centrifugal resistance. A commutator that is mechanically extremely stable up to 2,000 RPM can be mass-produced.

Further, since the shrink ring is insulated at the same time as the resin molding, the insulation is stable and no cost is required for the insulation. As a result, since the insulation is stable, the shrink ring can be mounted at a low cost by using a rigid steel ring without any need for insulation treatment.

Further, according to the second aspect of the present invention, it is possible to provide a commutator that is suppressed in the degree of outer diameter expansion and is stable even at high speed rotation.

[Brief description of the drawings]

FIG. 1 is a completed view of a resin mold commutator into which a shrink ring of the present invention is press-fitted.

FIG. 2A is a side view of the molded commutator. FIG. 2B is a cross-sectional view of the molded commutator.

3A is a side view of the commutator piece, FIG. 3B is a front view of the commutator piece, and FIG. 3C is a side view of the commutator piece.

FIG. 4 is a comparison diagram of the degree of outer diameter expansion showing the effect of the shrink ring.

FIG. 5 is a configuration diagram of a commutator using a conventional shrink ring.

FIG. 6 is a step waveform diagram of the resin mold commutator.

FIG. 7A is a view showing the commutator piece. FIG. 7B is a view showing a commutator piece provided with the riser.

FIG. 8 (a) is a partial cross-sectional view of the resin mold commutator, and (b) is a top view of the resin mold commutator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commutator piece 2 Resin 7 Shrink ring 8 Insulator 11 Surface cut 12 Side cut

Claims (2)

[Claims] 1. A commutator piece having a concave portion on the surface and a riser portion at an end, a commutator body having the commutator piece disposed on a side surface, and a shrink ring insulating portion provided in the concave portion. A commutator comprising a shrink ring press-fitted to the surface of the shrink ring insulating portion, wherein the commutator main body and the shrink ring insulating portion are integrally formed resin. 2. The commutator according to claim 1, wherein the shrink ring is mounted on one side of the commutator on the riser side.