Servo device for servo steering of vehicle.

摘要

The servo device according to the invention comprises, housed in the same casing (1), two coaxial rotary shafts (2, 3) connected to one another by a torsion spring (4) and one of which, of the driven type, is provided with a helical thread (6), a cylinder (7)/piston (8) assembly whose working chambers (9, 9') are supplied with pressurised hydraulic fluid by means of a directional control valve (10) driven as a function of the angular spacing between the two shafts (2, 3), an inner transmission joint (11) securely fastened to an output shaft (12) which meshes with the thread (6) of the driven shaft (3) and with a rack (14) carried by the rod (15) of the piston (8), and a bearing component (19) serving to retain the rod (15) in a position opposite the inner joint (11). This bearing component (19), as well as the piston lining (8) are made from a filled plastomer. The invention makes it possible to reduce friction and wear. <IMAGE>