Rotary valve for hydraulic power steering with reduced noise and linear boost characteristic

摘要

A rotary valve having chamfers (26,39) at the groove edges (31) of its input shaft (10) which, in conjunction with axially extending troughs (44) , form metering edge contours. The chamfers (26,39) and troughs (44) at the edges (31) of the grooves (18a,18b) interacting with sleeve slots (19) to reduce valve hiss and linearise the boost characteristic of the valve.