The invention discloses an energy-saving type prior unloading valve which belongs to the technical field of hydraulic steering systems of
engineering machinery. The energy-saving type prior unloading valve comprises a valve body, a prior valve core, a sliding valve, an unloading valve core and an LS control plug screw, wherein an oil channel CF, an oil channel P, an oil channel P2, an oil channel P1 and a return oil channel T1 are formed in a valve hole of the prior valve core; and the oil channel P2, a return oil channel T, an oil channel LS and an unloading
safety valve guide return oil channel T2 are formed in a valve hole of the unloading valve core. A
load sensing complete hydraulic steering hydraulic
system is formed by the energy-saving type prior unloading valve together with a
load sensing steering gear and a steering pump, the sliding valve is additionally arranged, and the movement of the sliding valve is controlled through the pressure of the steering gear LS, so that the divided and combined flow high / low
pressure control is realized, and the steering prior is ensured; and when a
loader is not steered, steering pump hydraulic oil is subjected to prior valve flow combination or load oil returning under the lower pressure, so that the pressure loss of the steering pump combination or the load oil returning in the working condition that the
loader is not steered is reduced, the unnecessary
energy loss of the
system is reduced to the maximum extent, the
oil temperature is lowered, and the energy saving effect is effectively achieved.