JPS6138591B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a powder metal commutator, and an object of the present invention is to simplify processing and easily mass-produce commutators of uniform dimensions.

That is, metal powder is filled into a mold (not shown) and compacted in a direction perpendicular to the plane of the paper in FIG. A metal powder cylinder 2 is made having the metal powder at equal intervals (Figs. 1 and 4). By controlling the type of metal powder and the amount of carbon powder (including binder-containing carbon powder) and molybdenum disulfide mixed into it, the electrical characteristics (contact (resistance, contact ripple, etc.) and mechanical properties (low friction, low brush noise, etc.).

After sintering the metal powder cylinder 2, a shaft 3 is passed through the center of the cylinder, and an electrically insulating synthetic resin 5 is filled and solidified into the hollow 4 of the cylinder around the axis and the slits 1a, 1b, and 1c. (Figures 2 and 5).

Next, the cutting blade 6 is brought into contact with the cylinder 2, and the cylinder 2 is rotated or the cutting blade 6 is rotated along the cylinder 2 to cut the slits 1a, 1b, and 1c from the outside of the cylinder 2.
Cut to the position shown by the chain line in Figure 2. As a result, the cylinder 2 becomes several (three in the illustrated example) segments 2a, 2b, and 2c that are insulated from each other, forming a powder metal commutator (FIGS. 3 and 6).

In some cases, slits 1a, 1b, 1c
Electrically insulating synthetic resin 5 and segments 2a and 2 inside
In order to prevent problems with the brush due to the difference in friction between the slits 1a, 1b, and 1c, the electrically insulating synthetic resin 5 in the slits 1a, 1b, and 1c is removed after the above-mentioned cutting process, and the resin surface is replaced with segments 2a, 2b, and 2c.
Lower than the surface of 2c.

Since the segments of the present invention are formed from powdered metal, a metal cylinder having several radially spaced slits at equal intervals can be easily obtained as described above. The product is obtained through several steps: filling the inside of the cylinder with electrically insulating resin and solidifying it, then cutting the outer peripheral surface of the cylinder, making it easy to mass-produce powdered metal commutators with uniform dimensions. .

Furthermore, since carbon can be contained in the segments 2a, 2b, and 2c, the friction between the brushes and the commutator can be reduced and thermal fusion can be reduced. As a result, brush noise is reduced and electrical contact is also stabilized. In addition, the contact ripple is small, and electric sparks due to unstable contact are reduced, resulting in longer brush life. Furthermore, by incorporating carbon into the commutator, a product can be obtained that has the effect of allowing the use of metal brushes that do not contain carbon, depending on the motor conditions.

Note that the terminal end of the rotating electric machine side coil 7 is fixed to a recess 8 formed inward at the end of each segment 2a, 2b, 2c with adhesive, solder, or the like. 7th・
FIG. 8 shows an example in which a coil end fixing piece 9 is provided protrudingly from the end of each segment 2a, 2b, 2c, the coil 7 is fitted into a recess 10 provided in this fixing piece 9, and the fixing piece 9 is caulked and fixed. If the fixing pieces 9 are provided at both ends of the segments 2a, 2b, and 2c as in this example,
The commutator is convenient because it can be assembled to the rotating electrical machine in either the left or right direction.

[Brief explanation of the drawing]

1 to 3 are front views illustrating the implementation steps of the method of the present invention, FIGS. 4 to 6 are side views of each of FIGS. They are a front view and a side view of the product. 1a, 1b, 1c are slits, 2 is a metal powder cylinder, 2a, 2b, 2c are segments, 3 is a shaft, 4
5 is an electrically insulating synthetic resin, 6 is a cutting tooth, and 7 is a coil.

Claims (1)

[Claims] 1. A metal powder cylinder having several slits radially outward from the cylinder at equal intervals is compacted and then sintered, and the inside of the cylinder and the slits are filled with electrically insulating synthetic resin and solidified. A method for manufacturing a powder metal commutator, which comprises cutting the metal powder cylinder from the outside until it reaches a slit to form a segment insulated by a synthetic resin in the slit.