ELECTROHYDRAULIC TRANSLATER DEVICE ALLOWING PARTICULARLY THE CONTROL OF A PRESSURE IN AN AUTOMATIC TRANSMISSION

摘要

A coil of an electromagnet (29) subjects to an attraction force a moving platine (30) of magnetic material inside which is housed a ball (32) of non-magnetic material closing the end of a passage (33) for the hydraulic fluid. The device further comprises electronic means to supply the coil (29) with a pulse unidirectionnal current of which the cyclic ratio and the mean value are servo-controlled to an order value represented by an electric control signal. The device may be used as a hydraulic potentiometer for defining a pilot pressure proportional to an electric control signal in a hydraulic control circuit of an automatic transmission in industrial vehicles.