GB1329957A - Valve for use in hydrulic or pnematic control systems - Google Patents

Abstract

1329957 Fluidic elements ROBERT BOSCH GmbH 29 Sept 1971 [9 Oct 1970] 45348/71 Heading G4P [Also in Division F2] A valve for use as a switching device in hydraulic or pneumatic control systems, comprises an annular chamber 8, Fig. 1, e.g. of circular or elliptical cross-section, having inlet ducts 22, 23 and an outlet duct 24 in one wall thereof and control ducts 12, 13 in its other wall. The lands 25 to 28 and 14 to 16 adjacent the ducts, define seating surfaces for the valve closure member 9. The latter is formed as a resilient split ring or band, e.g. of steel or plastics, and is pre-stressed against the outer wall of chamber 8. The valve of Fig. 1 is arranged to have a NOT function. When the control ducts are pressurized, the band 9 sealingly co-operates with the lands 25 to 28 to prevent flow between the inlet and outlet ducts. The inlet and outlet ducts are of part-annular form and communicate with, and progressively deepen towards, respective inlet and outlet passages (32, 31), Fig. 3 (not shown), in casing 1, the passages communicating with inlet and outlet pipes (p and y). The control pressure may be taken from the inlet pipe. The differential force across band 9 may be increased by throttle means disposed in the inlet pipe downstream of the branch for the control pipe x. The inlet and discharge ducts may be interchanged. In Figs. 5 and 6 (not shown), the control ducts are arranged in the outer wall of the chamber, and the inlet and outlet ducts are arranged in the inner wall, the band (9) being pre-stressed towards the inner wall. Fig. 7 (not shown) relates to an embodiment suitable for pressures of 100 atmospheres, and has six control ducts (55), four inlet ducts (57) and two outlet ducts (58). The valve shown in Fig. 9 controls two separate circuits via a common control pipe-line x, and has two annular chambers 60, 61 each containing a respective band 62, 63 and associated with respective control ducts 65 and 64. In a similar construction, Fig. 11 (not shown), the two annular chambers are connected in series with respect to the fluid flow, and each chamber is connected to an independent control pipe-line so that the valve has an AND function. Alternatively, in a construction having an OR function, Fig. 13 (not shown), the annular chambers are connected in parallel. In Fig. 15 the outlet duct 80 of an annular relay chamber supplies the control ducts 81 of a main annular chamber, passages 85, 86 and throttle 87 relieve the pressure at the outlet side of the annular relay chamber when the outlet duct 80 is closed by band 9. In a final embodiment, Fig. 17 (not shown), a solenoid pilot valve (90) is incorporated in the flow passage leading to control ducts in the inner wall of an annular chamber.