Design and performance test of crane multiway valve with double valve spools parallel structure

Traditional load-sensitive multi-way valves used in truck cranes suffer from excessive throttling loss and insufficient accuracy in small-flow control. To address this, a commutated single-connection multi-way valve with a parallel dual-spool structure (incorporating a quick-acting spool and a micro-acting spool as two commutated control spools) is proposed. This design aims to achieve low-pressure-loss rapid movement and high-precision positioning movement of hydraulic actuators under small-flow conditions. The commutated single-connection control principle of the multi-way valve was theoretically analyzed, and its single-connection structure was subjected to 3D modeling design, prototype processing, and assembly. Comparative experiments between the new valve and traditional load-sensitive multi-way valves were conducted: under fixed-flow input conditions, adjusting the spool displacements of the quick-acting spool and the traditional load-sensitive multi-way valve reduced the pressure difference of the new valve by 2.2 bar. Steady-state pressure-flow characteristic tests verified that the micro-acting spool, with its small area gain, exhibits higher flow resolution. In pressure-flow composite control, the micro-acting spool demonstrates smaller flow error values, which facilitates the realization of micro-motion in hydraulic actuators.