Motor drive system

摘要

A motor drive system is provided with two drive units so that the system may be driven not only by operating one of the drive units but by simultaneously operating both of the drive units in accordance with load condition. Both of the first and second drive units are provided with a motor and a gear reduction mechanism. The output gear of the second drive unit is mounted as a planetary gear of a planetary gear mechanism on the carrier. When the current is supplied simultaneously to both the motor of the first drive unit and to the motor of the second drive unit, the output gear of the first drive unit comes into mesh with the output gear of the second drive unit, combining the output forces of the first and second drive units to drive the load driving shaft. When the use of only the first drive unit is required to drive the load, the motor of the second drive unit is rotated reversely to move the carrier of the planetary gear mechanism to a refuge position, where the output gear of the second drive unit is de-meshed from the output gear of the first drive unit.