Yoke of rotary electric machine and manufacturing method thereof

Abstract

A yoke is produced by rolling up Zn-Al-Mg platinized steel plate of corrosion-resistance treatment where both ends thereof are tightly mated. On the outer peripheral surface of the yoke, plural linear grooves extending in the axis direction of the yoke are formed at a constant interval in the rolling step. Because the steel plate of corrosion-resistance treatment is prepared before initiating therolling step, it is not necessary to perform coating and electroplating after making a cylindrical shaped yoke, namely, not necessary to perform any coating and electroplating after making the yoke, and the grooves are not filled with reaction products. This increases the radiation capability of the yoke because of increase of the entire surface area of the yoke. The Zn-Al-Mg platinized steel hasa silver color and hardly absorbs radiant heat from an engine of a vehicle, and suppresses the increasing of the yoke temperature.

Description

Yoke for rotating electric machine and manufacturing method thereof technical field The present invention relates to a yoke forming a magnetic circuit of a rotating electric machine such as a starter mounted on a vehicle. Background technique For example, there are various techniques for manufacturing a yoke that is part of a rotating electric machine (or motor), such as a starter, mounted on a vehicle. Japanese Patent Laid-Open No. JPS64-60247 has disclosed such techniques as drawing and punching and stuffing. The preceding techniques perform stretching operations to form cylindrical bodies from steel plates. The latter technique performs a blanking operation to form a cylindrical body, followed by a caulking operation to seal both ends of the cylindrical body. However, two conventional techniques require coating to cover the surface of the cylindrical body with a corrosion-resistant film, or electroplating and then cutting the corrosion-resistant film on both end surf...

AI Technical Summary

Problems solved by technology

However, although this technique reduces the heat capacity of the motor in addition to reducing its size or volume, there is a limit to the magnitude of the reduction

Therefore, there is also the technical question of how to increase the radiation capabilities of the motor

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