| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic power steering device which reliably opens a bypass oil path even when a hydraulic pump is not temporarily stopped upon failure.SOLUTION: A second valve 32 is opened upon failure. Working fluid of a middle pressure chamber 43 flows from a middle pressure chamber 43 to a low pressure chamber 39 side via a second communication path 46 having a second throttle 47. A pressure in the middle pressure chamber 43 is lowered and a first valve 31 is opened. A first throttle 45 is disposed on the first communication path 44 which communicates high pressure chambers 41, 42 with a middle pressure chamber 43. When pressures in the high pressure chamber, middle pressure chamber and low pressure chamber are P, P, P, cross-sections of a first throttle and a second throttle are A, A, pressure reception areas which receive the pressures P, P, Prespectively with respect to the first valve 31 are S, S, S, the following relation is satisfied, the relation: A>A√[SP-(S-S)P]/√[(S-S)P-SP]. |
