| 摘要 |
A pilot-operated hydraulic pressure relief valve (HV) includes a main valve element (5) which is biased into a closed position by a spring (6). A pilot valve (VV1) has an open condition and a closed condition. A relief device (EV) is actuatable by the pilot valve (VV1) between an activated condition in which the force exerted by the spring (6) on the main valve element (5) is at a reduced level and a deactivated condition in which the force exerted by the spring on the main valve is at an increased level. The relief device (EV) includes a movable spring support (8) which supports a first end of the spring (6). A second end of the spring (6) is supported for movement with the main valve element (5). The movable spring support (8) is movable between a first position relatively far from the main valve element (5) when the relief device (EV) is in the activated condition, to decrease the biasing effect of the spring (6), and a second position relatively close to the main valve element when the relief device is in the deactivated condition, to decrease the biasing effect of the spring.
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