| 摘要 |
<p>A rotary actuator derives its power from a synchronous motor preferably of the AC type providing constant output speed, and from a non-synchronous motor, preferably of the DC type, in a helper capacity to provide additional torque for a load. Use of certain types of non-synchronous motors to provide a portion of the maximum torque is cheaper than using a synchronous motor whose size is adequate for the maximum torque requirement. A torque limiting clutch which couples the non-synchronous motor output to the synchronous motor output allows the non-synchronous motor to run compatibly with the synchronous motor. A hysteresis coupling type of torque limiting clutch is preferred. In a preferred embodiment, both of the motors drive a gear train, with the non-synchronous motor coupled to the gear train by the torque limiting clutch.</p> |
