The main drive shaft driven in part by the cylinder rotation, uniformly distributed over seven cylinder plunger shaft around the center line of rotation, by the spring center column slide shoe assembly against the variable head (or swash plate) on . Thus, with the rotation of the cylinder and the piston reciprocates complete oil suction and pressure operation. Manually variable pump flow by changing the rotational force adjustment hand wheel, turn the adjusting screw to drive the piston to move axially variable, variable head while driving around the center of rotation, change the angle of inclination, to achieve the purpose of the variable.