| 摘要 |
<p>A hydraulic pressure acting in a hydraulic reaction chamber of a power steering system is controlled. A spool valve is formed with portions having a greater and a smaller diameter, which portions are partly situated in an annular groove formed in a valve opening and communicating with the hydraulic reaction chamber. A spring is disposed to one side of the spool valve nearer the portion of a greater diameter to urge it toward the portion of a smaller diameter. Toward the portion of a smaller diameter, the spool valve abuts against a rod of a solenoid. The hydraulic pressure from a pump is introduced into the annular groove through a variable throttle formed in the portion of a greater diameter while the hydraulic pressure in the annular groove is returned to a tank through a variable throttle formed in the portion of a smaller diameter. As the hydraulic pressure in the annular groove rises, the spool valve is shifted in accordance with a difference in the pressure responsive areas, thus suppressing an increase in the reaction pressure.</p> |
