Hitachi, Ltd.

Hiroyuki Nagasawa

Tosio Tomite

Tatsuhiro Tani

Akira Takahashi

Hidemitsu Kobayashi

Rokuro Kikuchi

Kiyomasa Tsubota

Two or more imbalance correcting openings with the same cross-sectional configuration are provided in an armature core in parallel to a shaft in such a manner as to be equally spaced on a circumference which is concentric with the shaft, and weights are inserted in the adjacent openings to thereby correct any imbalance, the number of adjacent openings being selected to be (N-1)/2+1 or less when the number n of openings is odd and to be n/2 or less when the number n is even.

Armature for direct current motor with imbalance correction

A method of production of a cylindrical body from a sheet of steel formed at opposite sides with projections and cutouts complementary to each other. The method comprises the steps of rolling the sheet of steel and inserting the projections in the cutouts to provide a cylindrical blank, and compressing at least one of inner and outer peripheral surfaces of the cylindrical blank in a radial direction to reduce the thickness of the cylindrical blank and to stretch a portion of the cylindrical blank in an axial direction whereby the projections inserted in the cutouts can be brought into intimate contact with each other at jointed portions.

Method of production of cylindrical body

Growing community of inventors

Katsuta, Japan

Hiroyuki Nagasawa