| 摘要 |
<p>1306531 Fluid-pressure servomotor systems. INTERNATIONAL BASIC ECONOMY CORP 19 Feb 1970 [19 Feb 1969] 8070/70 Heading G3P An unloading valve 26 for a hydraulic system is opened to connect a pump 10 to a reservoir 12 when a high-pressure valve 32 is actuated and is closed to connect the pump to an accumulator 14 through a check valve 16 when a low pressure valve 56 is actuated, the high-pressure valve controling the unloading valve through a relay valve 38. When the accumulator is fully charged a pressure of, say, 1500 psi is applied to the valve 32 to connect a line 20 to a reservoir line 12 and allow fluid to flow through an orifice 24 from a line 18. The pressure drop across the orifice opens the valve 38 when it reaches 50 psi so that the line 20 has a further parallel flow path to the reservoir through a line 52, the already open low-pressure valve 56 and a pilot flow limiting valve 46 which is opened by the pressure drop across an orifice 44 whenever the valve 56 is open. The further flow thus provided through the orifice 24 opens the unloading valve when the pressure drop reaches a value of 100 psi. When pressure in the system falls, say, to 1400 psi the valve 56 and hence the valve 46 close to stop flow through the orifice 24 and thus close both valves 38 and 26. The valve 56 has a spring chamber 60 connected to the inlet to provide rapid closure as the system pressure falls. All of the valves are mounted in a common housing and orifices 80, 82 and 84 operating in conjunction with oil reservoirs, such as 90 damp the movements of the valves 26, 38 and 46. A further orifice 74 operating in conjunction with a check-valve 72 provides a rapid opening and slow closing characteristics for the valve 26. The high and low-pressure responsive valves are loaded by manually adjustable springs.</p> |
