| 摘要 |
<p>A first front face of a main control spool of a main control valve is loaded with a constant pressure, whereas the opposite face is loaded with a controlled pressure to control the fluid passages to and from a hydraulic actuator. The control pressure is adjusted by means of a two-edge control of the pilot control spool of a pilot control valve which is actuated by a single proportional solenoid against the force of a spring. The advantages obtained thereby result in a substantial savings in manufacturing expenditure and a substantially improved control operation.</p> |
