| 摘要 |
PCT No. PCT/EP94/01931 Sec. 371 Date Mar. 12, 1996 Sec. 102(e) Date Mar. 12, 1996 PCT Filed Jun. 14, 1994 PCT Pub. No. WO94/29158 PCT Pub. Date Dec. 22, 1994In a servo-assisted steering system which is intended for motor vehicles, a steering valve (1) is provided for controlling the pressure fluid. The steering valve (1) has two intake seat valves (7, 8) and two outlet seat valves (10, 11), which are adjustable via an actuating device (23) as a function of a rotary motion of a steering shaft. In the neutral position of the steering valve (1), the outlet seat valves (10, 11) are closed. The intake seat valves (7, 8) can be acted upon in the closing direction by the force of compression springs (13) and are not opened until after the closure of the respective associated outlet seat valve (10, 11). One limiting piston (24) is provided for each side of the steering valve (1). Each limiting piston (24) is acted upon on one side by the pressure prevailing in the work chamber (3, 4) of a servomotor (5) and on the other by a limiting spring (25), which in the neutral position of the steering valve (1) keeps the limiting piston (24) at a distance from the closure body (12) of the intake seat valve (8). If the force of the pressure acting upon the limiting piston (24) exceeds the force of the limiting spring (25), the limiting piston (24) is applied to the closure body (12) of the intake seat valve (8) and acts upon it. With such an arrangement a "cutoff or actuating moment limitation" is attained.
|
