GB972771A - Improvements in or relating to hydrostatic bearing systems - Google Patents

Abstract

972,771. Fluid bearings; lubricating; valves. DOWTY HYDRAULIC UNITS Ltd., and A. CAMERON. Nov. 10, 1960 [Aug. 10, 1959], No. 27274/59. Headings F2A and F2V. A control valve for regulating the supply of fluid from a source of substantially constant pressure to a fluid bearing comprises a variable restrictor valve, a movable pressure-responsive member subject in one direction to the fluid pressure at the bearing and in the opposite direction to an opposing force which increases in magnitude when there is an increase in fluid pressure at the bearing. In an embodiment, the valve 14 comprises a housing having parts 15, 16 which are screwed together, the part 15 having a centrally disposed inlet connector 17 connected by a pipe 18 with a pump 19 which supplies lubricant at constant pressure, and the part 16 having a centrally disposed connector 21 connected by a pipe, not shown, to a reservoir, not shown. The inlet connector 17 leads to a bush 22 in the housing part 15 which receives a needle 25 screwably attached to a piston 24, mounted in a bore 23 of the housing 15. The piston 24, which is the pressure-responsive member, is urged by a spring 26 so that the restrictor valve is closed when the pump 19 which supplies the pressurized oil is stationary. When the pump is operated the oil is forced along a pipe 18, into the inlet 17 of the housing 15, through the restrictor valve and into an annular chamber 27 which is connected by radial holes 28 to a groove 29 formed in a ring 31 which surrounds the housing 15. The groove 29 leads to an outlet connector 34 having a pipe 13 attached thereto which conveys the oil to a recess 12 in the bearing in which a shaft 10 is maintained concentric. In another embodiment, the valve has an inlet connector 41 which opens into a chamber 42 having an orifice 43 which connects to a cylinder bore 44. The latter is connected to a cylinder bore 46 by a step 45, the bore 46 having a cross-sectional area twice that of the bore 44. A stepped piston has a portion 47 in the bore 44, a portion 48 in the bore 46, a needle 51 attached thereto, and is urged by a spring 49. When the pump 19 is stationary the restrictor valve is opened by the spring 49 and when the pump is operated the oil is passed through a connector 41 to a chamber 42, past the restrictor valve into a restricted passage 52 leading to the bearing recess 12 via the pipe 13, which is also connected by a pipe 53 to the bore 46. An increase of bearing-load causes a reduction of flow through passage 52 and an increase of flow in passage 53 so that the piston is moved and the restrictor valve is opened.