Kinematic and kinetostatic analysis of the six-link straight-line generating converting mechanism of the unbalanced sucker rod pumper drive

Abstract

The results of kinematic and force analysis of the new six-link converting mechanism of the sucker rod pumper drive (SRPD) are presented in this paper and the advantages of the alternative design are substantiated. Using a straight-line generating mechanism allows reducing essentially converting mechanism dimensions and metal consumption as compared with traditio nally used SRPD with swinging balancer and crank-based counterweight, first of all, due to eliminating the complicated arc head (so-called «horse-head») of the existing units. However, in order to make sure the working capacities of non-balancer mechanism, kinematic and force characteristics have to be studied. The results of mathematical modeling of the six-link mechanism confirm the qualitative advantages of the straight-line generator. As a result of the study of the rectilinear-guiding mechanism as a transforming mechanism for the drive of sucker rod pumping units, the laws of motion of the links, position, speed and acceleration of all points were determined. To solve the problem of kinematic analysis, the method of closed vector contours was used, which makes it possible to determine the functions of the position of links and analogs of speeds and accelerations. When solving the problem of strength analysis, the equilibrium of each link was considered. As a result of force analysis, jointly solving the equilibrium equations of the links of the six-link hinge-lever mechanism, the reactions of the hinges of the mechanism are determined. A computer model for studying the kinematics and kinetostatics of the converting mechanism of the sucker rod pumping unit drive has been developed

Analytical solution of the problem of dynamic synthesis of a six-link straight-line converting mechanism of the sucker-rod pumping drive

“…By choosing the value of the correction factor k, the mass of the counterweight and the distance of the center of the counterweight from the axis of rotation were selected. The distance of the center of mass of the counterweight from the axis of rotation of the crank is determined in the first approximation by (1). In the 2nd column of Table 1, the balancing results are obtained through the correction factor, which adjusts the distance of the center of mass of the counterweight from the axis of rotation and is entered manually until the two peak values of shaft torque M become equal.…”

“…An analytical solution to the problem of optimal dynamic balancing is obtained in general form, where the counterweight on the crank is displaced by the angle 1 П , α and the counterweight on the third link is offset by the angle 3 П . α Then the unknown variables are…”

“…In [1], the movement of a six-link hinge-lever mechanism was investigated and the following problems were solved:…”

“…If it was possible for the mechanism in some way to satisfy the conditions of exact balancing, then these conditions will persist for any law of motion of the input link and, therefore, the balance of the mechanism (both static and dynamic) becomes an intrinsic quality of the mechanism [1].…”