| 摘要 |
<p>1486354 Fluid-pressure servomotor systems CATERPILLAR TRACTOR CO 12 Nov 1975 [17 March 1975] 46751/75 Heading G3P [Also in Division F2] The head portion 76 of a spring-loaded spool 74 of a flow responsive pressure relief valve 12 is provided, downstream of a frusto-conical nose portion 90, with a stepped and shaped portion 92, 94, 96 constructed so as to prevent oscillation of the valve by providing a proportionally greater "lift" of the spool the greater the fluid-pressure in an inlet passage 32 of the valve above a predetermined pressure at which the valve opens. As the valve first opens, Fig. 2, a thin stream of fluid impinges mainly on the frusto-conical surface 94 causing a reaction on the spool, a small proportion of which is in the axial direction, whereas when the valve is wider open, a thicker stream of fluid impinges mainly on the annular step 98 causing a reaction on the spool, a large proportion of which is in the axial direction. An annular valve seat 40 is provided between the inlet passage 32 and an outlet chamber 38. As shown, the valve is opened by a pilot valve 68 and is used to control the pressure of fluid operating a double acting hydraulic jack 22.</p> |
