Power steering valve with two spools of different size to compensate unbalanced cylinder

摘要

A power-assist device for an automotive steering system employs spool valves with different external diameters to control the fluid pressure in smaller and larger area chambers of a pressure control valve which controls pressure in an unbalanced cylinder device. The different size of spool valves are disposed within different sizes of bores formed through a housing of the pressure control valve for defining wider fluid path area for introducing larger amount of working fluid into the smaller area chamber in comparison with that for the larger area chamber and narrower fluid path for draining the working fluid in the smaller area chamber for lower drainage rate in comparison with that for the larger area chamber.