Cam structure of one block pump

The invention belongs to the technical field of engines, in particular relates to a monoblock pump, and more in particular to a cam structure of monoblock pump. A cam is divided into four sections by the structure, and corresponding functions are used according to the function of each section: in the first section that is an accelerating section, the cam uses a concave cam with the maximal acceleration as the accelerating section; in the second section that is a middle oil supply section, the speed of the oil supply section remains constant so that the acceleration is zero, thereby guaranteeing continuity requirements due to calculation in the combination with the third section; in the third section that is a transition section, straight line drop acceleration function is used, and the variation tendency of allowable spraying pressure of contact stress and the descending tendency of injection end pressure basically tallies; and in the fourth section that is a decelerating section, a negative acceleration (abs