PURPOSE: To achieve highly accurate adjustment of the phase angle between a fixed magnetic field and brush through simple operation by enabling coarse adjustment through the circumferential movement of a lid member against a casing and fine adjustment through the circumferential movement of a brush base against the lid member with a fine adjustment mechanism.
CONSTITUTION: To adjust the phase angle between a fixed magnetic field generated by a permanent magnet and brush, a fine adjustment mechanism 17 is provided in addition to a coarse adjustment mechanism. For coarse adjustment, a brush unit 16 mounted on a lid member 5 through a brush base 6 is turned round a rotation center C to determine its approximate position against the permanent magnet fixed to the housing 7. Then, turning a cam 70 on a fine adjustment mechanism 17 slightly turns the brush base 6 provided with an upright part 81 round the rotation center C relatively to the lid member. Thus, the above procedure accurately positions the brush by slightly moving it in A circumferential direction along with the brush base 6.
EGAWA YOSHIAKI
NISHIWAKI SATOSHI
