| 摘要 |
A pump piston structure of a hydraulic cylinder includes a pump piston having an aslant circular groove formed on a circumferential surface of the pump piston and interconnected to a through hole on a distal surface, a movable O-ring installed at the aslant circular groove, a penetrating hole formed between a distal surface of the pump piston and a piston rod and blocked by a pressure valve, and an oil suction hole formed separately on the pump piston and the piston rod for sucking hydraulic oil to push the hydraulic cylinder in the reciprocal movements of the pump piston, and when the hydraulic cylinder is loaded with a heavy object, some of the hydraulic oil at the pump piston returns to the piston rod to reduce the resistance of operating the pump. |
