Hitachi, Ltd.

Akira Ishida

Koji Sato

Michio Kuroda

Kiyoshi Namura

Fumio Kato

Yoshiaki Yamazaki

Tetsu Imai

Shigeo Higuchi

Tsutomu Iwasaki

Akio Sohma

Norimasa Chiba

Tutomu Iwasaki

This invention concerns a rotary electric machine, for example, a synchronous machine having salient rotary magnetic poles, which is equipped with a built-up type rotor. The built-up type rotor consists of a plurality of rotary members, which are coupled in the axial direction into an integral form. In such a built-up type rotor, the rotary members are sometimes displaced with respect to one another in the radial direction by centrifugal forces to which they are subjected during operation (rotation). As a result, the rotational balance of the rotor is lost, which tends to cause oscillations. Therefore, by skillfully exploiting the centrifugal forces which the rotary members undergo during operation (rotation), the radial displacements of the rotary members to one another are suppressed, thereby also serving to suppress the generation of oscillations.

Electric motor with a built-up type rotor using tapered sections

A plurality of turbine buckets annularly arranged around a rotor are each provided with a ledge disposed at right angles to the outer surface of each bucket. Each ledge includes a leading end portion and a trailing end portion each formed therein with a vertical hole, leading and trailing end portions of the ledge of each turbine bucket extending in opposite directions on both sides of the bucket. There are provided cover pieces each interposed between ends of the adjacent two turbine buckets and formed on the upper surface with a plurality or cylindrical projections adapted to be loosely received in the vertical holes formed in the ledges of the adjacent two turbine buckets. Contact surfaces adapted to be brought into contact with the undersides of the ledges are formed on the upper surface of each cover piece and interposed between the cylindrical projections, and an upper end portion of at least one of the cylindrical projections is machined to provide an enlarged diameter projection portion so as to preclude dislodging of the projection from the hole whereby the cover piece can positively connect the adjacent two buckets together.

Bucket cover attachment

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Hitachi, Japan

Akira Ishida