| 摘要 |
PURPOSE:To allow the device to combine high speed and high torque and to obtain the device having excellent operability by driving a moving gear directly by engaging it to a first and a second driving gears in an advance side position, and driving a first and a second driving gears so as to be reversed each other through a first and a second intermediate gears and an idle gear in a turning position. CONSTITUTION:When a motor 42 is rotated in the advance direction, a moving gear 48 is engaged directly with a first and a second driving gears 34, 52 by turning force of a motor gear 44 and rotated in the same direction. On the other hand, when the motor 42 is rotated in the turning direction, the moving gear 48 is engaged with a first and a second intermediate gears 30, 50 by turning force of the motor gear 44, and also, since one of them is engaged through an idle gear 32, a first and a second driving gears 34, 52 rotate in the reverse direction to each other. In such a way, a reduction gear ratio of the gear can be heightened by a portion engaged with a first and a second intermediate gears 30, 50 at the time of turning, and it becomes a low speed gear, compared with the time of advance, therefore, driving force can be transferred effectively to the left and the right caterpillars against a load at the time of turning. |
