The lower part of the outlet valve has a cross section, which can both guide and pass diesel fuel. There is a small cylindrical surface under the cone of the outlet valve, called the depressurizing ring band, whose function is to make the oil pressure in the high-pressure oil pipe drop rapidly at the end of the oil supply, so as to avoid oil dripping phenomenon at the spray hole. When the ring belt falls into the valve seat is to make the upper volume increases quickly, the pressure decreases rapidly, stop spraying quickly. 

 Complex structure of the axial piston pump, manufacturing process, material requirements are very high, so it is a high technology content of the hydraulic components. 

 Oil return process The plunger upward oil supply, when upward to the plunger on the slanting groove (stop supply side) and the sleeve on the oil return holes, the pump room low pressure oil circuit will be with the plunger head of the center hole and radial holes and slanting groove communication, the oil pressure drops suddenly, the outlet valve in the action of the spring force to close quickly, to stop the oil supply. Thereafter, the plunger will have to go up, when the cam cam part of the turn over, under the action of the spring, the plunger and go down. At this point the next cycle begins.
Variable pump (motor), in recent years, the use of more and more widely, and the new structure and control of the rapid development of various manufacturers are constantly improving the design to meet the needs of the continuous development of automatic control of hydraulic systems. 

 Plunger hydraulic pump types, the former plunger parallel to the cylinder axis, along the axis according to the plunger movement can be divided into axial plunger type and radial to the plunger type movement of the two major categories, the latter plunger perpendicular to the oil distribution axis, along the radial movement. These two types of pumps can be used as hydraulic pumps, but also for hydraulic motors. 

 Discharge valve and discharge valve seat is also a pair of precision coupling, pair grinding can not be interchanged, the fit clearance of 0.01mm.