FIG. 11 is a cross-sectional view illustrating a structure of a brush motor 51 as a third example. Here, a cross-sectional view of a stator 3 and a rotor 6 is displayed to be superimposed on a cross-sectional view of a commutator piece 9 for the sake of convenience. Elements corresponding to the elements described in the first example are denoted by the identical reference signs, and the description thereof is appropriately omitted. The brush motor 51 includes three pairs of magnet magnetic poles 5, five coils 7, and fifteen commutator pieces 9. A combination of (p, s, c) is (3, 5, 15), which is a six-pole/five-slit motor. Note that a commutating pole 14 is omitted in a core 10 of the brush motor 51 according to the third example. As a result, a slit width W between adjacent blades 13 is secured, and an electric wire of the coil 7 is easily wound.
FIG. 12 is a view illustrating a magnet angle θM and a blade angle θW of the brush motor 51. In the brush motor 51 of the third example as well, the blade angle θW is preferably set to the magnitude of the magnet angle θM or more (θW≥θM). As a result, the magnet magnetic flux is easily picked up by the teeth 11, and the magnetic flux is effectively utilized.
