双变径摆轮抽油机运动学计算的一种有效方法

An effective method for kinematic calculation of pumping unit with double offset wobble wheels

双变径摆轮抽油机是一种摆轮采用变径技术的无游梁式抽油机。进行运动学计算时，由于大小两个摆轮采用变径技术，而且相位不同，悬点位移、速度、加速度与曲柄转角之间的关系很难用数学式直接表达出来。针对这一问题，给出了双变径摆轮抽油机运动学计算的一种简单有效的方法：假设柔性件的长度不变，利用数值计算的方法进行求解。第一步，求出小摆轮转角与曲柄转角之间的数值对应关系；第二步，求出悬点位移与大摆轮转角之间的数值对应关系。由于大小两摆轮为同一个构件，悬点位移与曲柄转角之间的数值对应关系可由以上两步联立求出，进而利用差分法可求出悬点速度和加速度与曲柄转角的关系。

In the kinematic analysis of a pumping unit with double offset wobble wheels, the relations between the displacement, velocity and acceleration of the polished rod and the rotating angle of the crank are difficult to be expressed directly owing to the difference of the diameters and initial phase angles of the wobble wheels. Thereby an effective method for the kinematic calculation of the pumping unit -the numerical method is presented. On the assumption that the length of the flexible parts is constant, the numerical relations between the rotating angles of the small wheel and the crank and between the poished rod displacement and the rotating angle of the big wheel are worked out respectively. Thereafter the numerical relation between the polished rod displacement and the crank rotating angle can be worked out, and the relations between the velocity and acceleration of the polished rod and the the rotating angle of the crank can be worked out by using the differential method.