The Research And Design Of The Downhole Non-circular Planetary Gear Motor

The most used downhole tools are turbine drill and screw drill in geological drilling and oil drilling now.But these two kinds of drill both have shortcomings,turbine drill drilling speed is too high,the output torque is too small;screw drill rubber stator can not withstand high temperatures and the life is short.Based on the above background,this paper trys to design a new kind downhole drill---Non-circular Planetary Gear motor that could overcome the shortcomings of the two drills.Firstly,according to the requirements of the working environment and the motor parameters of downhole motor drilling tool,doing the diameter of 95 mm assembly drawings of two kinds of downhole non-circular planetary gear motor.Then through modifying the matlab software programming to determine the displacement V,torque T,the number of teeth of noncircular planetary gear internal gear and externalgear and polar radius of the 95 mm motor;drawing two types(small width and big width)noncircular planetary gear train.Then study the distribution principle and design the corresponding distribution mechanism,so the small width noncircular planetary gear train and distribution mechanism form a gear section,the gear section connecte with each other in parallel,then torque output.Finnally,check the planetary gear and output shaft strength of the two types of downhole noncircular planetary gear motor,and choose a suitable motor.(1)According to the requirement of the working environment and motor parameters,determining the overall parameters,designing the overall process and structure of the motor.(2)Modifying the matlab program,in the original program,the internal gear diameter is the 0.9times of the drill diameter,now because of the designing structure changing,we let the internal gear diameter is equal to the drill diameter;in the original,planetary gear tooth width is 0.3times the diameter of the drill,now in accordance with the inputting gear width doing the related programming operation.Secting the type of planetary gear train,then according to the modified program,calculation of structural parameters of the selected type of planetary gear train,according to the structural parameters obtained,doing the structure designing of two types of noncircular planetary gear train.(3)Designing the distribution mechanism and gear section.Firstly,analyzing the principle of 4-6 type distribution mechanism,position and shape of distribution hole,then designing the structure of the distribution mechanism;analysis of shunt、collecting principle,gear section working principle,then the structural design of the gear section.(4)Through the assembly drawing of two types(diameter 95mm)downhole noncircular planetary gear motor,comparing the advantage and disadvantage of two programme.Two type motors,one is each planetary gear train and distribution plate forming the gear section parallel,outputting the required the torque;the other is the big width noncircular planetary gear train,directly outputing the required torque.(5)Checking the strength of planetary gear and output shaft of the downhole noncircular gear motor.Firstly,check the strength of planetary gears,divided into contact strength and bending strength.And then to check the strength of the two output shaft respectively,analyzing the stress,drawing the force diagram、bending moment diagram and torque diagram,finally,check the strength according to the formula.(6)Comparing two types of motors,choose a suitable downhole non-circular planetary gear motor.