GB1229731A - - Google Patents

Abstract

1,229,731. Fluid-pressure servomotor systems. MESSIER. Jan. 14. 1969 [Jan. 15, 1968; Dec. 23, 1968], No. 2183/69. Heading G3P. A valve for regulating a pressure PU, Fig. 3, as a function of an electric current comprises a magnetic force motor for operating a movable closure member 23, a jet nozzle 24 and an orifice plate 25 supplied under pressure from a hydraulic source PA, a slide valve 31 controlled by the pressure PC and established between the diaphragm and the jet nozzle and regulating the pressure PU as a substantially linear function of the electric current, the magnetic force motor and the jet nozzle being constructed as a separate, removable body of revolution about an axis Y-Y with the closure member 23 movable along that axis and the slide valve 31 having a neutral position from which it is displaced if the pressure PU deviates from a prescribed value. The closure member 23 is carried by a movable core 3 centred by springs 14, 15 and suspended from two fine metallic diaphragms 12, 13. A spring 17 enables the position of the core to be adjusted while magnetic shunts 19 allow the relationship between current flow and core displacement to be adjusted. The slide valve 31 is centred in a casing 32 by springs 34, 35 and adjusted by a screw 42. Throttling the flow through the nozzle 24 increases the pressure PC to move the valve 31 to the left and increase the pressure PU until equilibruim is re-established. Movement of the valve 31 is the opposite direction connects the pressure PU with a return line R to decrease its value. Fig. 10 shows an alternative construction of slide valve in which ports 62, 64 for the regulated pressure PU are connected by recesses 72, 73 with a return port 61 or the supply pressure port 63. The supply pressure acting through a bore 76 on the left hand of the valve is balanced by the regulated pressure acting on the right hand end through a bore 78 and the control pressure PC acting on an area S2. The closure member 112, Fig. 11, in this embodiment controls a jet 113 supplied through a cylindrical filter 115 and is carried by a movable rod 89 biased upwardly by notched diaphragms 91, 92 against an adjustable spring 93. The connections to the motor are effected through a socket 103, Fig. 10, secured by screws 104.