| 摘要 |
<p>1,185,726. Fluid-pressure servomotor systems. BORG-WARNER CORP. Nov.6, 1967 [Nov.16, 1966], No.50407/67. Heading G3P. A shock pressure occurring in either line 38 or line 40 connecting the opposite ends of a double-acting motor cylinder 24 to a directional spool valve 42 is relieved through a passage 62 inter-connecting the lines and normally closed at its ends by identical pilot operated relief valves 70, 76 arranged to open at increasingly high pressure with increasing static pressure. The relief valve 70 comprises abutting hollow plungers 108, 110 slidable in a bore 112. The plunger 108 has an integral poppet 68 normally closing the passage 62 and contains a pilot valve 114 biased by a spring 116 to close a displaceable tube 122 having a flange 124 slidable in a bore formed in the plunger 110. The compression of the pilot spring 116 increases with increasing pressure due to the static pressure acting on the flange 124 displacing the tube 122. Pressure in the line 40 acts through passages 128, 130, 132 on the end of the plunger 110 and through passage 58 on the end of the plunger 108 which is of smaller effective area than the plunger 110 to maintain the valve 70 closed. When the pressure rises, the pilot valve 114 opens to exhaust fluid acting on the plunger 110 to a return passage 137, 54 and the plungers thus move to the left opening the passage 62. Pressure in passage 62 forces the poppet 74 of the valve 76 away from its seat 72. The spool valve 42 has an axial bore 90 in which slides an anti-cavitation shuttle 80 which automatically moves to connect inlet pressure in the port 52 to the passage 58 or 60 experiencing the low pressure.</p> |
