JPH037043A - Manufacture of commutator - Google Patents

Abstract

PURPOSE:To obtain a commutator which can resist against high speed rotation and heat by forming a metal galvanization layer onto the outer circumference at commutator chip holding section then securing a conductive metallic cylinder to the metal galvanization layer thereafter separating the metal galvanization layer from the cylinder and forming a commutator chip. CONSTITUTION:A groove 11a formed in a ceramic body 1 is filled with resin 12 thus forming a commutator chip holding section 10. Then a metal galvanization layer 2 is formed onto the outer circumferential face 10 of the commutator chip holding section 10 thereafter a conductive metallic cylinder 3 is applied thereon and brazed to the metal galvanization layer 2. Then a notch 4 reaching to the resin 12 is made axially from the outer circumference of the cylinder 3 and the cylinder 3 is separated uniformly from the metal galvanization layer 2 thus constituting a commutator chip. Since the commutator chip is secured through the metal galvanization layer to the ceramic body, bonding force sufficient to resist against high speed rotation can be provided. Furthermore, since ceramic can be employed in the commutator chip holding section, heat resistance is improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a commutator for a DC machine.

[Prior Art] Conventionally, in a method for manufacturing a commutator, a commutator insulator having a plurality of recesses on the outer periphery is preformed from ceramic, and copper is poured into the recesses of the insulator to form commutator pieces. A method for doing so is disclosed in Japanese Patent Laid-Open No. 132751/1983.

The above method is extremely effective as a method for manufacturing a commutator with excellent heat resistance.

[Problems to be Solved by the Invention] However, in recent years, DC machines for automobile starters are required not only to have excellent heat resistance but also to be able to withstand high speed rotation.

Since the commutator pieces manufactured by the above manufacturing method are heavy, it is difficult to withstand centrifugal force due to high-speed rotation.

The present invention has been devised in view of the above-mentioned drawbacks, and an object of the present invention is to realize a method for manufacturing a commutator that can easily manufacture a commutator that has excellent heat resistance and can be adapted to high-speed rotation.

[Means for Solving the Problems] The method for manufacturing a commutator of the present invention includes forming a plurality of grooves extending in the axial direction on the outer peripheral surface of a ceramic body having a cylindrical shape, and forming a plurality of grooves in the circumferential direction, and filling the grooves with an insulating resin. A first step of forming a commutator piece holding portion by embedding, and a second step of forming a metal plating layer on the outer peripheral surface of the commutator piece holding portion and fixing this metal plating layer and a conductive metal cylinder. and a third step of forming a notch from the outer periphery of the cylinder to a depth reaching the insulating resin in the axial direction and separating the cylinder and the metal plating layer in the circumferential direction to form a commutator piece. It is characterized by

[Function] According to the above configuration, even if centrifugal force acts on the commutator due to high-speed rotation, the commutator pieces are fixed to the ceramic body through the metal plating layer, so the adhesion force is sufficient, and the ceramic body It never comes off. Furthermore, since the commutator pieces are light and plate-shaped, the centrifugal force generated by high-speed rotation is not large.

Furthermore, since the notch does not reach the ceramic body, it is easy to form the cutout. Furthermore, since ceramic can be used for the commutator piece holder, it has much better heat resistance than one made of resin.

[Example] The method for manufacturing a commutator according to this example consists of three steps.

The first step is to mold the ceramic raw material powder into a compacted body,
A ceramic body 1 in which this compacted body is sintered to form grooves 11a extending in the axial direction on the outer circumferential surface 11 and having equal angular intervals in the circumferential direction.
(q (Fig. 1). In this embodiment, the cross-sectional shape of the groove 11a is rectangular, but it is not limited to a rectangle and may be of other shapes such as a semicircular shape. A resin 12 is embedded in 11a.The upper surface of the resin 12 is made to be even with the outer circumferential surface 11 of the ceramic body 1.The commutator piece holding portion 10 is formed by this step.

In the second step, metal is first plated on the outer circumferential surface 11 of the ceramic body 1 and the resin 12 of the commutator piece holding portion O to form a metal plating layer 2. Next, a conductive metal cylinder 3 having an inner diameter approximately equal to the diameter of the commutator piece holding part 10 on which the metal plating layer 2 is formed is inserted into the commutator piece holding part 10 and brazed to the metal plating layer 2. (Figure 2).

In the third step, the notch 4 is cut in the axial direction from the outer periphery of the cylinder 3 assembled in the second step to a depth that reaches the resin 12.
(Fig. 3), and the cylinder 3 and the metal plating layer 2 are separated at equal intervals in the circumferential direction to form commutator pieces.

When the commutator is manufactured by the above manufacturing method, the cylinder 3 is brazed to the metal plating layer 2 and is firmly fixed to the ceramic body 1, so that it can sufficiently withstand the centrifugal force caused by the rotation of the commutator. Furthermore, since the notches 4 do not need to reach the ceramic body 1, they can be easily formed by cutting, and the insulation properties of the commutator pieces can be maintained. In general, by using the ceramic body 1 as the base material, it also has excellent heat resistance.

Also, instead of the ceramic body 1 in the first step, the groove 11a
A ceramic coating may be used on the surface of a metallic matrix having a . Furthermore, in the second step, after the cylinder 3 is brazed to the metal plating layer 2, the resin 1
The same effect can be obtained by melting and removing the grooves 11a to form voids, and then providing the notches 4.

[Effect] The method for manufacturing a commutator of the present invention is to form a commutator by forming a plurality of grooves in the axial direction (extending) on the outer peripheral surface of a cylindrical ceramic body, forming a plurality of grooves in the circumferential direction, and embedding an insulating resin in the grooves. A first step of forming a piece holding portion, a second step of forming a metal plating layer on the outer circumferential surface of the commutator piece holding portion and fixing the metal plating layer to a conductive metal cylinder, and Excellent heat resistance is achieved by forming a notch from the outer periphery to a depth that reaches the insulating resin in the axial direction, and separating the cylinder and the metal plating layer in the circumferential direction to form a commutator piece. At the same time, it is possible to manufacture a commutator that can be adapted to high-speed rotation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a ceramic body in the first step of the example. FIG. 2 is a sectional view showing the state after the second step is completed. FIG. 3 is a sectional view showing the state after the third step is completed. 1... Ceramic body 10... Commutator piece holding part 1
1a...Groove 2...Metal plating layer 4...Notch 12...Resin 3...Cylinder

Claims (1)

[Claims] (1) A first step of forming a commutator piece holding portion by forming a plurality of grooves extending in the axial direction and circumferentially on the outer peripheral surface of a cylindrical ceramic body, and embedding insulating resin in the grooves. a second step of forming a metal plating layer on the outer peripheral surface of the commutator piece holding portion and fixing the metal plating layer to a conductive metal cylinder; A method for manufacturing a commutator, comprising: a third step of providing a notch to a depth and separating the cylinder and the metal plating layer in the circumferential direction to form a commutator piece.