Patent ID: 7646121
Filing Date: 2010-01-12
Classification: H02K

Abstract:
1. A stepping motor comprising: a rotor including a cylindrical permanent magnet that is multipole magnetized in a circumferential direction; ring-shaped first and second yoke units that are arranged so as to be mutually stacked along an axis of the rotor while surrounding a periphery of the rotor, and respectively include notches; an electrical connection member of resin material that includes external connection terminals, is secured to the first and second yoke units, and includes claw sections, provided in a surface facing the first and second yoke units, that engage the notches of the first and second yoke units so as to position the electrical connection member with respect to the first and second yoke units; and a pair of lid members that enclose the first and second yoke units from both sides thereof along the axis, and support the rotor so as to be rotatable around the axis, each of the first and second yoke units including: a ring-shaped air-core coil having an insulated surface; an outer yoke that accommodates therein the air-core coil and includes a plurality of magnetic pole teeth arranged at fixed intervals in a circumferential direction of the air-core coil; and an inner yoke that includes a plurality of magnetic pole teeth arranged at fixed intervals in a circumferential direction of the air-core coil, and is combined with the outer yoke such that the magnetic pole teeth are arranged alternately and at equal intervals in a noncontacting state with respect to the magnetic pole teeth of the outer yoke, wherein winding ends of the air-core coil are electrically connected to the external connection terminals, and the electrical connection member includes a nonmagnetic metal member which is electrically isolated from the air-core coil, and is provided in a region that contacts at least the first and second yoke units.