Multiple purpose hydraulic valve

摘要

866,985. Fluid-pressure servomotor control systems. LEAR Inc. Sept. 19, 1957 [Oct. 9, 1956], No. 29474/57. Class 135. A control valve for an hydraulically operable device (not disclosed) is provided with means for receiving low force level electrical input signals and means for receiving high force level mechanical input signals, the hydraulic output to the operable device being the algebraic sum of both inputs. Electrical input signals are fed to a torque motor 50 which actuates a rod 48 to rock a lever 36 about a fulcrum point 40. Movement of the lever 36 imparts an axial movement to a pilot valve 22 by means of a rod .34., The pilot valve 22 is arranged to control a slave valve 72 in the following manner. High-pressure hydraulic fluid from a source of supply enters the valve casing at port 124 with a return line from the casing via port 122. The device to be operated is controlled by fluid flow through ports 121 and 123. From the port 124 high-pressure fluid passes to the space surrounding the shank 82 of the slave valve 72. Further fluid passes through the internal passage 122 to the left-hand end of the slave valve and through port 108 to the space surrounding the shank 32 of the pilot valve 22. On the pilot valve being moved to the left high-pressure fluid in the space surrounding the shank 32 enters port 117 and flows to the right-hand end of the slave valve 72. Due to the right-hand end of the slave valve having a larger area than the left-hand end the valve will move to the left. This movement through a spring 88 causes the lever 36 to rotate about its fulcrum point to restore the pilot valve 22 to its neutral position again. In the new position assumed by the slave valve 72 the port 123 will be exposed to high-pressure fluid in the space surrounding the shank 82 and the port 121 will be placed in communication with the return port 122. Thus a flow of fluid to the operable device will be established proportional to the displacement of the slave valve. The high force level input signal is fed into the valve by displacement of the sleeve valve 64 which; assuming that the slave valve is in the position shown in the figure will direct high pressure fluid through port 123 when moved to the right and through port 121 when moved to the left. Movement of both the slave valve 72 under an electrical signal and the sleeve valve 64 under a mechanical signal will cause a flow of highpressure fluid proportional to the algebraic sum of the two input signals. Both inputs may be electrical or both may be meehanical.