JPS6132372A - Molded rectifier - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a molded commutator for a commutator motor used in vacuum cleaners, etc. of home appliances.

Structure of conventional examples and their problems Conventionally well-known molded commutators are made by casting an insulating material such as phenol onto a commutator piece made of a drawn conductive material, punched or formed from a cylindrical conductive material, and then, The bridging portion connecting adjacent commutator pieces is removed to electrically isolate each commutator piece. On the other hand, it is customary for each commutator piece to be prevented from coming off due to centrifugal force by being secured to the cast insulator by projections or the like formed on each commutator piece.

However, in recent years, commutator motors have become smaller and lighter, their performance has improved,
As speeds have increased, the life of the brushes has been significantly shortened due to the commutator pieces floating, and in severe cases, accidents have occurred where the commutator breaks.

In order to investigate the cause, the inventor of the present invention made the following regarding the above commutator:
As a result of many experimental studies, the following problems were found. This will be explained below with reference to FIGS. 4 to 7.

Fig. 4 is a perspective view of a commutator, Fig. 6 is a sectional view of a conventional commutator, Fig. 6 is an enlarged sectional view of a commutator piece of the commutator, and Fig. 7 is a view of the commutator during operation. The floating state of the commutator piece is shown. In the figure, 1 is a cast insulator, and 2 is a commutator piece consisting of a sliding part 3 and leg parts 4.

In the above configuration, if the commutator pieces 2 are made smaller, it is advantageous against centrifugal force, but fusing, which is used as an electrical connection means between the commutator pieces 2 and the rotor windings (not shown), etc. Due to the resistance welding, the heat is high for a short period of time, and the heat capacity is small, which can actually thermally degrade the resin that makes up the cast insulator 1, lowering the bonding strength with the resin, and causing the commutator pieces to deteriorate. 2 floating occurs. Therefore, it is necessary to increase the size of the commutator piece 2 and maintain insulation from adjacent commutator pieces. Now, the commutator piece 2 shown in FIG. 6 has a neck dimension λ1 of 30% of the sliding section dimension 22, and a leg taper T of 5°.

At this time, although it is desired to increase the leg bottom dimension 23, it cannot be increased too much due to the insulation distance from the adjacent child piece. From Fig. 7, the difference in level between adjacent commutator pieces due to this commutator is as follows.
8μ will definitely generate a spark.

There were also destruction accidents. The boundary surface 6 has a gap due to a difference in thermal expansion with the commutator piece (copper). Therefore, the size of the neck 60 causes the surface to vibrate during high-speed rotation, which is one of the causes of sparks.

OBJECTS OF THE INVENTION The present invention aims to improve the commutator performance by improving the shape of the commutator pieces described above.

Structure of the Invention The present invention has a commutator piece having a sliding part and an intermediate tapered part with nine leg parts, and the dimension of the neck at the boundary between the sliding part and the intermediate tapered part is determined by the size of the neck part of the sliding part. The length is 40 degrees or more, the taper angle of the intermediate taper portion is 8° to 150 degrees, and a protrusion is provided at the tip of the leg to improve the strength of the punch.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. In the figure, 1 is a cast insulator, 12 is a plurality of commutator pieces held and fixed by the cast insulator 1, and a sliding part 1
3, an intermediate tapered portion 14, and a leg portion 16. The intermediate tapered portion 14 has a taper angle T of 8° to 15′ so that the sliding portion side has a smaller diameter, and a protrusion 16 is provided at the tip of the leg portion 1.

Now, taking an example of a prototype commutator of the present invention for a commutator motor with an input of 500 W and a maximum rotational speed of 2500 Orpm, the dimensions of each part in FIG. 2 are as follows.

Commutator outer diameter 25M, surface dimension L1 of sliding part 13 is 3m
m, neck dimension λ at the boundary between the sliding part 13 and the intermediate tapered part 14
2 is 1.5M, the bottom dimension 23 of the intermediate taper part is 2 lines, the protrusion dimension λ4 provided at the bottom of the leg 15 is 2mm, and the commutator piece height is 4°5mm.The pullout strength is as shown in Figure 8. As shown in the figure, this is an improvement of about 30 inches compared to the conventional model. Furthermore, as shown in Fig. 3, the height difference between adjacent commutator pieces during high-speed rotation is 1 to 2 μm, and the effect of the present invention is that it is definitely effective in preventing floating of the commutator pieces. According to the invention, the pull-out strength of the commutator piece can be greatly improved without adding any special parts or increasing the external dimensions, and it is possible to prevent the surface of the commutator piece from shaking during high-speed rotation. This reduces the height difference between the commutator elements, which has a significant effect on spark generation and commutator breakage.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the molded commutator of the present invention, Fig. 2 is an enlarged sectional view of the commutator pieces, and Fig. 3 shows the steps between the commutator pieces when the commutator is rotated at high speed. 4 is a perspective view of a conventional molded commutator, FIG. 6 is a sectional view of the same commutator, FIG. 6 is an enlarged sectional view of a commutator piece of a conventional example, and FIG. 7 is an enlarged sectional view of a conventional molded commutator. FIG. 8 is a diagram showing the difference in level between the commutator pieces when the commutator is rotated at high speed, and is a comparative data diagram of the pull-out strength of the conventional example and the commutator pieces of the present invention. DESCRIPTION OF SYMBOLS 11... Cast insulator, 12... Commutator piece, 13... Sliding part, 14... Intermediate taper part, 15... ... Legs, 16...
··protrusion. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Figure 4 Figure 6 Figure 7 Figure 8 Millet fleas

Claims (1)

[Claims] The commutator piece has a three-stage shape of a sliding part, an intermediate tapered part, and a leg part, and the dimension of the neck at the boundary between the sliding part and the intermediate part is 40% or more of the sliding part dimension, and the intermediate tapered part Taper angle of 8°
A mold commutator formed by forming an angle of ~15° and protrusions on the legs.