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 (50). In the fine speed control mode, the motor rotation rate is a function of the flow rate through a proportional-flow valve (42) that is downstream of the motor (12).