| 摘要 |
PROBLEM TO BE SOLVED: To enable suppression of resistance variation of a coil in a motor having a magnet having four or more magnetic pole portions, a common brush, a low-speed driving brush and a high-speed driving brush.SOLUTION: The number of teeth and the number of segments are equal to each other. When the number of magnetic pole portions of the magnet is represented by P and the number of teeth is represented by S, (2S/P) is an odd number. The width of each brush and the arrangement position of brushes in the peripheral direction of the rotational axis are set so that all the three kinds of brushes of a common brush, a low-speed driving brush and a high-speed driving brush do not simultaneously start to short-circuit respective two segments adjacent to each other in the peripheral direction.SELECTED DRAWING: Figure 4 |
