| 摘要 |
<p>856,528. Fluid-pressure servomotor-control systems. BENDIX CORPORATION, [formerly BENDIX AVIATION CORPORATION]. Dec. 16, 1958 [Dec. 27, 1957], No. 40583/58. Class 135. In a two-stage control valve a double-acting pilot valve member 206, is displaceable in response to an electric signal to vary the flow of fluid through two pilot orifices 120, 122 carried on the main valve spool 88 to create a pressure differential which acts on the end of the spool to move it. The spool 88 is slidable in a liner 36 having a number of internal annular grooves and external passages (not shown), and the pilot orifices 120, 122, which are formed in a nozzle 124 fitted in the spool, are fed together with the end chambers 101, 103 through axial bores from radial bores 112 in the spool. The pilot valve member which has a forked end that opposes the pilot jets is actuated by an electric torque motor 200 and pressure fluid is supplied through passage 38 in the liner to grooves 44, 46, and eventually exhausts through grooves 74, 78 to passage 22, together with the flow from the pilot jets. Further passages connect grooves 56, 58 and grooves 64, 66 and also lead to opposite sides of the power device to be controlled, so that if the pilot valve member is moved anticlockwise pressure is built up in the orifice 120 and reduced in the orifice 122 and a corresponding pressure change takes place in the end chambers 101, 103 to move the valve spool downwards and restore the pressure balance, and pressure fluid is supplied through groove 58 to the power device and returns through groove 66 to groove 78 and then to exhaust through passage 22. The device operates in the opposite sense for a clockwise rotation of the pilot valve.</p> |
