An electro-hydraulic device for controlling a servo-actuated gearbox

摘要

In an electro-hydraulic device for controlling a mechanical servo-actuated motorcar gearbox, a pressurised fluid is used as working fluid. The device comprises a hydraulic control for the clutch by means of an actuator (13) and two single actuators (10), one for selecting the gears and the other for engaging the gears. The actuators are controlled by an electronic processing unit for driving the gearbox control shaft (11) responsive to signals from sensors fitted on the vehicle. The pressurised fluid control circuit for operating the actuators (10,13) comprises a first proportional three-way two-position solenoid valve (26) disposed upstream of a first set of two on-off solenoid valves (27,28), and a second proportional pressure solenoid valve (30) disposed upstream of a second set of two on-off solenoid valves (32,33).