Study On System Dynamics Of Rack Type Pumping Unit

Against some of the shortcomings of the existing beam pumping unit、chain pumping unit、tower type pumping unit and long ring rack type pumping unit, this paper puts forward a new kind of gear and rack type pumping unit. According to the technological requirements of gear and rack type pumping unit, design the structure、determines the size of parts and some basic parameters. It can solves the problem of the existing beam pumping unit、chain pumping unit、tower type pumping unit and long ring rack type pumping unit, and it has characteristics of good energy saving effect、high reliability、long stroke、big load、Light weight and easy to maintain etc. Thesis research mainly includes the following several parts:First of all, gives the overall design of gear and rack type pumping unit. The main structure of the pumping unit including the tower、counterweight consists of motor, speed reducer and gear、mobile way mechanism consists of guide rail, hydraulic cylinder and pulley. This paper designs the structure of the new kind of gear and rack type pumping unit, and calculate the suspension point static load, and choose the motor, reducer and model of wire rope, preliminarily determine the weight of the counterweight. Its working principle is double motor synchronous drives gear and rack joint, the counterweight shuttle along the rack to move up and down by reversing the drive motor, upload force on sucker rod through the steel wire rope to make the rod as the counterweight shuttle up and down reciprocating movement for sucker.Second, the motor adopts frequency conversion control, and established the mathematical model of gear and rack type pumping unit suspended point movement. This paper adopt two methods to study the dynamic characteristics of rod string, one is to use the finite difference method for solving one-dimensional wave equation of sucker rod, the other is to create an entity model simulation in ADAMS and solve, by comparing the two methods to know the dynamic characteristics of rod string.Third, take the maximum rod load to check the tower’s structural strength in the process of running smoothly and during work over, to observe the stress distribution of tower, and maximum stress value is less than the yield limit of material, so the tower structure is reliable. And using the finite element method to calculate the weight shuttle in six different positions in front of the rack type pumping unit12order natural frequencies and the corresponding vibration mode, avoid may cause resonance in advance.Finally, the rigid-flexible coupled model of a tower for the flexible body, the rest of the rigid body is established, in view of the wire rope simulation adopted two kinds of methods, one kind is to use gear and rack to simulate the steel wire rope, the other is a discrete wire rope into many segments, and use the flexible connection for simulation. Compare the two kinds of methods, study the dynamic situation of the gear and rack type pumping unit in weight were83.89KN,73.89KN,63.89KN, pumping red times were4.2min-1,3.5min-1,3min-1.