Patent ID: 7388308
Filing Date: 2008-06-17
Classification: H02K

Abstract:
1. A built-in motor type spindle device comprising: a housing including a cooling jacket to which a cooling medium is supplied from an outside; a main shaft; a static pressure bearing for supporting the main shaft rotatably with respect to the housing by a pressure transmission medium which is supplied to a clearance between the static pressure bearing and the main shaft; and an AC servomotor comprising: wherein phase arrangements of at least one of the opposite polarity poles of the two lines of magnets and the pairs of cores are displaced from each other in a circumferential direction, and, wherein at least one of the two lines of magnets and the two pairs of cores has skews whose directions are opposite to each other wherein when both the two lines of magnets and the two pairs of cores have the skews, angles of the skews are different from each other.