Electric rotating machine having radially outwardly extending bulge on yoke

摘要

A plurality of magnetic poles (3) each made of a permanent magnet is circumferentially arranged at regular intervals on the inner circumferential surface of a yoke (2). Bulged portions (5) axially formed on a wall portion of the yoke (2) between the adjacent two magnetic poles (3). The bulged portions (5) extend in a direction from the inner circumferential side of the yoke (2) toward the outer circumferential side thereof. Each bulged portion (5) is semicircular in section and connected with a cylindrical wall portion (2a) of the yoke (2) through a radius (5a). An angle (&thetas;2) between a side surface (3a) of each magnetic pole (3) and the inner circumferential surface of each bulged portion (5) is larger than an angle (&thetas;1) between the side surface (3a) of each magnetic pole (3) and an inner circumferential surface of the cylindrical wall portion (2a) of the yoke (2). An open end of the yoke (2) is closed with an end cover (17) fixed to the yoke (2) with a plurality of through-bolts (4) by tightening. Each of the through-bolts (4) is installed in the yoke (2) through the inner side of each of the bulged portions (5) of the yoke (2).