| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize arrangement of a motor and a speed reducer in the back and forth, and width direction and profile of a power unit, by arranging a unitized motor which drives a rear axle at a rear part, arranging a driving shaft of the motor, a shaft of the speed reducer, and the rear axle relatively at vertexes of a triangle. SOLUTION: A case 8 which is at the rear part of a power unit 1 and includes a motor 20, a speed reducer 40, and a supporting part of a rear axle 11, is placed in a space of a rim 118 of a rear wheel 15 containing outwards of the motor 20 and the speed reducer 40 so that it is housed in one side. An output shaft of the motor 20, a decelerating shaft of the speed reducer 40, and the rear axle are arranged so that lines Tr connecting them each other as vertexes form a triangle. Therefore, the supporting part of the rear axle whose part is contained in the motor 20 and the speed reducer 40 is housed in a profile line of the rear wheel 115, almost half of its width is housed in a rim 118 of the rear wheel 115, and driving mechanism which is motor driven type and has the speed reducer 40 can be housed in the rear wheel 115 compactly. |
