| 摘要 |
<p>A pilot operated hydraulic control valve for use in conjunction with a solenoid modulator to provide brake pressure modulation on heavier vehicles, particularly in so-called automotive anti-lock systems. The pilot operated slave unit has an inlet valve operable by travel of one piston (17) and an exhaust valve operable by travel of another piston (16). One is a main piston (16) which travels in response to pilot signal pressure (22) and during part of its travel controls travel of the other piston (17), an auxillary piston, away from a stopped position towards which the auxillary piston is biased. Thus the valve has three distinct and stable positions (supply to delivery, delivery held and delivery to exhaust) determined by the pilot signal pressure (22) and the effort travel characteristic. It can therefore imitate as a slave unit, the pressure modulations of a three-state antilock solenoid valve (4) but with increased fluid flow.</p> |
