Reducing valve operation
In order to release parking brake, system uses the pressure from main pressure of supply line. So we
need to decrease the pressure by using this valve.
(1) Supply pressure goes to brake chamber to release the brake.
(2) If the pressure of brake chamber exceed the specified value(spring tension), main pressure push the
valve to the right becasue of area difference of valve and disconnect passage between main pressure and
brake chamber. Therefore the parking pressure cannot exceed the setting pressure.
Picture text:
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