JPS6455048A - Rotary power machine - Google Patents

Abstract

PURPOSE:To make it possible to perform the smooth rotation and to reduce the number of grinding processes by providing both ends of a permanent magnet with grinding surfaces almost at right angles to a central line bisecting a central angle viewed from both ends of the permanent magnet. CONSTITUTION:A coil 40 is provided to either a stator 4 or a rotor 4, and at the same time, a plurality of permanent magnets with the shape of almost a circular arc are placed and provided on the circumference, and the grinding surfaces 52 at almost right angles to the central line l divided a central angle fronting on the ends sections of permanent magnets 20 into a half and located in the same plane are provided to the circumferential ends sections of them. Therefore, the radial thickness from the internal peripheral surface to the peripheral surface of the permanent magnets 20 is gradually reduced at the area of the ends sections where the grinding surface are located. Accordingly, since the intensity of magnetic force is gradually decreased at the ends sections, the inversion in the direction of magnetic pole between the permanent magnets 20 adjacent to each other becomes slow, and the cogging is decreased. And, the grinding surfaces can be easily obtained, so the working is easy.