Hydraulic transmission for fork lift truck - has variable pump and electronic control of transmission ratio

摘要

The vehicle IC engine transmission has a variable angle hydrostatic pump and several hydrostatic motors. Hydraulic pressures are monitored in the pump and in the motors. The motors are mounted near the wheels and can act as retarders. An electronic controller regulates the pump setting w.r.t. the vehicle speed, and system pressures. Increasing system pressure reduces the pump setting and hence increases the transmission ratio. Lifting of the throttle pedal setting introduces a retardation effect with reduced strain on the mechanical brakes. The application of the brakes also enhances the retardation, with the retardation proportional to the brake setting. ADVANTAGE - Improved control, reduced brake wear. Reduced engine loading, avoiding stalling of engine.