| 摘要 |
1,137,855. Fluid-pressure servomotor systems. JOHNSON SERVICE CO. Jan.21, 1966 [Jan.25, 1965J, No.2939/66. Heading G3P. A spring-loaded piston 13 controlling a load 3, e.g. a valve or damper, is responsive to pressure variations in a chamber 5 of a control valve 4, the chamber being supplied by a pump 1 via a restriction 10 and being connected via restrictor tube 21 to the chamber above the piston. The pressure in the chamber is varied by means of a leak-valve 7 co-operating with a leak-port 6, the leak-valve being adjustably mounted on the free end of a lever 23 hinged at 28. The armature 31 of an electromagnet 8 is fixed to lever 23 intermediate the hinge and the leak-valve. The electromagnet comprises a U-shaped core 29 having a winding 30 encircling one leg thereof. A balance weight 32 is attached to lever 23. As shown, the load is connected to a controller 9 connected in series with the electromagnet so that if the load varies from its set point the controller varies the energization of the electromagnet to cause repositioning of the load. The magnetic torque line 38 Fig. 3 has a smaller slope than the hydraulic torque line 39 and intersects the latter at the set point 37, such an arrangement causing the leak-valve to return to the set point if it is disturbed by vibrations on the line. If the restrictor 21 were not present to delay the response of the piston 13, the latter would respond to undesired movement of the leakvalve away from the leak-port, and would cause flow into chamber 5 and out of the leak-port, thereby causing the hydraulic torque line to follow path 40 and prevent the return of the leakvalve to the set point. The tube 21 may be replaced by an orifice. |
