The output torque of common asynchronous motor is basically constant

but the brace axis negative torque is alternate load

so both the load performance are not able to "harmonious" match

lead to lower circulate efficiency and higher energy consumption of pumping unit.A crank guide six bar pumping unit that is designed by the beam structure and guide bar mechanism

realizes a small fluctuating form of the brace axis negative torque

and obviously raises the load rate and the power utilization rate of electromotor.The pumping unit decreases energy consumption.A mathematic movement and dynamic modeling is built up by design proposal

and the key parameters that influence the negative torque line-shape are analyzed.Based on Matlab optimization toolboxes

all parameters optimum design was made.Finally

energy-saving effect is analyzed.