| 摘要 |
The present invention is a vehicular power steering system having an 'open-center' control valve (10) that has substantially zero hydraulic flow gain at zero input deflection angle with minimal control orifice area. A valving sub-assembly is used which functions to rapidly restore hydraulic gain at relatively small input deflection angles. The valving arrangement includes small transverse leakage slots (40', 54') formed in a valve spool that are in fluid communication with either input or return flow distribution slots. The leakage slots are configured to form parasitic flow orifices which fluidically interconnect the output slots (32a, 32b) formed in the valve sleeve and which communicate with the fluid chambers formed on opposite sides of a piston in power cylinder (18). Accordingly, a selectively variable leakage path is provided across the power cylinder. The parasitic flow orifices may have uniform and/or non-uniform areas for customizing performance characteristics. |
