| 摘要 |
PROBLEM TO BE SOLVED: To prevent occurrence of fretting in a return passage to a pump, in a flow controlling device for a pump rotational speed sensing type power steering. SOLUTION: A fretting preventive structure for a return passage 5 of a pump 14 in a flow controlling device for a power steering is provided as follows: pressure fluid discharged from the pump 14 whose discharging flow rate is increased accordingly to the increase of rotational speed of the pump is supplied to a power steering device through restriction passages 9, 10 in a supply passage 4, and excessive pressure fluid is fed back to a suction side of the pump 14 by means of a flow rate adjusting spool valve which adjusts an opening of the return passage 5. In such a case, a relief chamber 24 is recessed on an inner wall surface of a spool housing hole 3 of the flow rate adjusting spool, particularly at its portion substantially faced to the return passage 5. The relief chamber 24 is so formed that the pressure fluid can be injected faster than the case using the return passage 5, when a spool 2 of the flow rate adjusting spool valve is pushed by the pressure fluid and moved. |
