| 摘要 |
<p>A priority flow rate control valve (4) increases a distribution ratio of pressurized oil to a power steering device (1) of a fork-lift track via a power steering oil passage (9) as a differential pressure between a power steering pressure (PS) in the power steering oil passage (9) and a pilot pressure (LS) decreases. A load signal port (24) which outputs a pressure indicative of a load exerted on the power steering device (1) and the power steering oil passage (9) are connected via two orifices (26A, 26B), and the pilot pressure (LS) pressure is extracted from a point between the two orifices (26A, 26B). By providing a bypass passage (31, 35) which bypasses one of the two orifices (26A, 26B) and a bypass valve (30) which opens and closes the bypass passage (26A, 26B), a response of the priority flow rate control valve (4) can be increased temporarily.
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