Lu Yi

School of Mechanical Engineering,

Yanshan University,

Qinhuangdao 066004, China

Tatu Leinonen

Department of Mechanical Engineering,

University of Oulu
P. O. Box 4200

90014, Finland

Abstract: A torsion hydraulic time-delay coupler is developed, which is used for buffering the reversing impact torque of the long-stroke petroleum pumping unit system. Through its hydraulic buffering function, this coupler converts the abrupt reversing rotation of the driving shaft into a smoothly and uniformly variable reversing rotation of the shaft of the working machine (the drum of the long-stroke pumping unit). According to the practical working conditions and the Bernoulli equation in fluid mechanics, the formulas for calculating the hydraulic pressure and the torque in reversing are derived. Then, through the energy method, the delay time and rotational angle are determined. Finally, the related factors that influence the relationship of torque versus delay time are analyzed by means of a program generated to calculate the results. The calculations show that this coupler produces an excellent buffering effect.