| 摘要 |
PURPOSE:To ensure given flow rate to a power steering in spite of the change of viscosity due to the change of temperature in a pressure fluid by providing an annular throttle between an union and a control spool. CONSTITUTION:The pressure fluid discharged from a pump is supplied to the first valve chest 18 of a hole 11 for incorporating a valve, from an annular throttle 39 between an union 12 and a control spool 30 through a supply passage 14. The control spool 30 slides to the side of a discharge port 23 by overcoming against a spring 33 when the pressure within the supply passage 14 is reached to a given pressure, and the pressure fluid within the first valve chest 18 is discharged to a power steering from the discharge port 23 through a fluid passage 31 and a passage 25 of the throttle. It is possible to enlarge a gap in a radial direction by providing the annular throttle 39 and therefore, the change of the pressure difference in the front and the rear of the annular throttle 39 against the change of viscosity in the pressure fluid is reduced. Accordingly, it is possible to prevent inconvenience of sliding the control spool 30 before the rotation number of the pump is sufficiently increased, even if the viscosity of oil is increased in a lower temperature. |
