Abstract: To control the differential cylinder with only one pump directly in closed loop, a new technical proposal that dividing one of the flow distributional window of axial piston pump into two ones is suggested. When used, one of the new flow distribution windows is linked to the rod chamber of the differential cylinder and another one is linked to the oil tank to balance the area ratio of the differential cylinder. But the transition zone between the two new distributional windows is not on the dead spot, when the cylinder passed through this region, there will be a big volume change, that causes a large flow pulse and pressure impact, so this transition zone must be reasonable designed to reduce its influence. First the simulation model of new three outlet axial piston pump is established with multi-disciplinary simulation software SimulationX. The flow pulse and pressure impact of the single plunger and the pump outlets are researched by comprehensive analysis on the structures of transitional triangle groove, damping orifice and pre-compression angle. Through simulating, reasonable valve plate structure parameters are obtained. Further a prototype pump is manufactured. The pressure pulsation characteristic tested. The correctness of the simulation results and designed parameters are confirmed. The research results extend the types of axial piston pump.

Key words: Axial piston pump, Flow fluctuation, Pressure pulsation, Valve plate