Stabilized speed-control system for a hydrostatic transmission

摘要

A hydrostatic rotary power transmission system that provides a stable rotation rate at very slow rotation speeds is provided. The system operates in two speed control modes, one being a normal mode for use in the rotation rate range of 50 rpm to the maximum rated speed and a second or fine speed control mode for use in the rotation range of <1.0 to 250 rpm. In the normal control mode, the rotation speed is a function of the displacement of the hydrostatic pump. In the fine speed control mode, the motor rotation rate is a function of the flow rate through a proportional-flow valve that is downstream of the motor.