| 摘要 |
<p>A servo valve for a power steering booster comprises a power piston and cylinder assembly including a power piston reciprocatively movable therewithin and a spool assembly including a hollow spool for controlling selective supply and discharge of hydraulic pressures onto and from both sides of the power piston, a pair of reaction pistons slidably fitted within ends of the hollow spool to form a reaction hydraulic chamber therewithin, a reaction spring interposed between the reaction pistons, cover plates closing the ends of the hollow spool, through which a steering input transmission shaft passes, and reaction support pins of bearing rollers made with a high dimensional accuracy held in guide holes formed in the cover plates between the respective reaction pistons and partitions located at ends of a housing slidably accommodating the spool assembly and having ports for the selective supply and discharge of hydraulic pressures, thereby eliminating the high accuracy machining of parts associated with the spool to achieve the precise neutral position of the spool.</p> |
