| 摘要 |
A priority valve is disclosed for controlling fluid flow between a power source and a secondary hydraulic function operated by the power source. The priority valve includes a housing having first and second bores formed therein. An inlet passage connects the power source to the first bore while an outlet passage connects the first bore to the hydraulic function. A priority function is also fluidly connected to the power source upstream of the priority valve. A valve spool is positioned in the first bore. The valve spool is movable between a first position blocking fluid flow from the first passage to the outlet passage and a second position permitting fluid flow therebetween. A pin is movably positioned in the second bore and has an enlarged end which extends into the first bore. Springs are present for urging the valve spool toward the first position and the pin toward the spool valve. A load signal passage connecting the priority function to the second end of the first bore. When full fluid is demanded by the priority function the valve spool moves toward its first position. When the priority valve demands less than full flow the spool valve moves toward its second position. If the priority function demands pressure approaching a maximum pressure which can be delivered by the power source the enlarged end of the pin contacts the valve spool and forces it toward its second position. |
