According to the huge and transientcharacteristicsof the openingforce in the valve drive systemof the large hydraulic press

a new kind of cam profile curve composed with two sections of curve that matches the loading characteristics

using involutes to realize the zero pressure angle in heavy load

and using conic as profile curve

implementing the joint point smooth connection and the high liftof the mandrill in low load is designed.The optimal eccentricity of the camisobtained through analysis established mathematical model of combined curve.Applying the cam of this kind of profiles in the valve driving systemof the large hydraulic press

kinematics analysis results showthatthe impact is low

and the flexibility is good at the joint point.Compared the cam in the field applications with the cam presents

this scheme can effectively reduce the driving torque of the cam mechanism

and greatly reduce the lateral force of the rod in heavy load.