GB1140583A - Fluid-pressure servomechanism - Google Patents

Abstract

1,140,583. Fluid-pressure servomotor systems. MOOG Inc. Jan.18, 1966, No.35191/68. Divided out of 1,140,582. Heading G3P. A servomechanism comprises a valve 1A controlling an actuator 17 in response to electrical signals fed to a solenoid 18. The solenoid actuates a flapper 21 controlling the leak from nozzles 19, 20 to provide a pressure differential in chambers 43, 48 at the ends of a spool valve 28. The spool valve controls the flow of fluid to and from chambers 56, 58 of the actuator 17 and a feedback is provided between the actuator and flapper by spring 66 and between the spool and flapper by spring 68. Positive and negative pressure feedback is also provided in respect of the load as measured by the pressures in the passages 60, 62 leading to the actuator. The pressure in passage 60 is connected through passage 91, 84 to chamber 81 and through restrictor 92 to chamber 86 which is connected to chamber 73. Similarly the passage 62 is connected to chambers 80, 88 and 74. A summation piston 72 has areas subjected to the pressures in the chambers 73, 74, 80, 81. The restrictions 92, 94 and piston 86 provide a low pass filter and the areas 71, 78 of the summation piston 72 are preferably larger than the areas 79, 79' thus the piston 72 provides a positive feedback to the flapper through the spring 96 in response to the mass or inertia of the load moved by the actuator. The Specification also describes other methods of action of the pressure feedbacks which are described and claimed in Specifications 1,140,582, 1,140, 584 and 1,140, 585.