Power steering control valve

摘要

A hydraulic fluid control valve (18) for a power steering gear (10) includes first and second relatively rotatable valve members (60, 62) which direct hydraulic fluid to flow between the valve members (60, 62) from inlet ports (78) to return ports (108). The valve members (60, 62) define a plurality of orifices (110) that enlarge and a plurality of orifices (110) that constrict upon relative rotation of the valve members (60, 62). A pair of the constricting orifices (110b, 110c) are located in parallel between the inlet ports (78) and the return ports (108). Those orifices (110b, 110c) begin to constrict at the same time, and subsequently reach fully constricted conditions at staggered times, upon relative rotation of the valve members (60, 62) from neutral positions.