| The oil-water well tractors are important equipments in carrying the test appliances and repairing wells in finishing horizontal wells.It is very valueable to enhance the adaptability in working environment and the security in tracting of tractors by doing optimize research.This article base on Research project of China Petroleum Science and Technology Innovation Fund(2012D-5006-0209).We will start our research from these following fields: Design the oil-water well tractors' systems,structures' optimizes design,simulation experiments and physical model experiments.Base on the specifieness of tractors' working condition,we used the modulav method to research the structure parameters of telescopic oil-water wells' tractors and main machine system functional units.By calculate,we confirmed the joint structure tractors' structure parameters that under the constraint of well pipes axis' axial bending parameters.By analyzing the configuration,we designed a supporting and locking structure which is mainly using straight rack locking pressure and use flexible arm guide as assistant and transmission by rigid links.This structure could raise the reliability of tractors' fixed-points and expansion and tightening actions.We also designed supporting structure that has segmental spring leafs as supporting arm.It has adaptive elastic reset ability and increased the motion flexibility of tractors.What is more,we designed a joint structure that has 4-SPS(PS)parallel structure that has three rotational freedom and one axial motion degree of freedom.It could expend the working place of tractors.Base on the analysing of the motivation and loading characteristics of tractors' main structures,we start our researchs in the fields of kinematics and dynamics.First,we did the displacement and force analysis to the supporting and blocking structure.Then we combined orthogonal experimental analysis method and virtual work principle to build motion characteristic function and piston rod thrust equation in order to describe structures' working character.We also designed the locking blocks' structure parameters to solve the problem of using less motivation to gain bigger traction force.We used “pseudo-rigid-body model” and virtual work principle to build force equation of supporting structures' supporting arms' pseudo-rigid-body model.Then we got the relationship between supporting arms' nolinear large displacement elastic deformation and stress.We also used spatial mechanisms and matrix theory to do the pose and speed's positive and negative solutions analysis and force analysis in order to get kinematic's positive and negative solutions algorithm.Then we can build dynamics equation and get the homogeneous Jacobean matrix of movement's speed and force.After we get the structures' parameters under singular configuration,we can totally comprehend the kinematics and dynamics characters of joint structures.For the working demand of tractors' main structure,we can build a corresponding object function and raise an algorithm of systematic structural parameters' optimum design.Our optimize objective is to minimize the piston thrust under the condition that the sustain force must be satisfied.In this case,we did the optimize research of the supporting rods' length and radial dimension of the point which connect supporting rod and bearing.In order to realize the optimize objective that minimize the size of supporting arm's structure while satisfy the demanding of support,we choosed supporting arms' arc length,bending radius and cross section height as optimize variables.We also used joint strcture side chains' pose angles,the distance of platform and side chains' cross-sectional area as optimize variables.After totally considerate the technology of manufacturing,strength,rigidity and fatigue condition,we built a mechanical model and a optimize design rule of tractors' main structures.We calculated the model by complex method to optimization the structure parameters of tractors' main structures.Then we finished the optimize design of the tractor.Finally,we solved the contradiction that structure size of tractors' motivation function unit is small while it has to output bigger power.We could build a three-dimensional visible entity models and do some simulation researchs to tractors' main structures and parts by using Solid Works.By using this software,we confirmed the strength of some key parts and researched the dynamic characteristic while tractors are passing pipe hinders.We also did many dynamics simulation experiments of support locking,stabilizer and joint structures while they are passing hinders in straight pipes,throught bent pipes and many under-well conditions.We got the side chains' flexible contral parameters of joint structures' rotation angle and simulation experiment datas while tractors are working under well.At last,we validated the rationality of structures' and machines' optimize parameters.According to the structures' designs parameters which are from optimize calculation,we built tractors' physical model.By this model we can simulate the working condition and build experiment devices to begin our researchs.We built some experiment devices for testing supporting force,pulling force and supporting force to do some dynamics researchs to tractors' main structures.We validated the block abilidy of supporting and locking structures and supporting ability of supporting structures.Then we got the relationship between hydraulic pressure systems' pressure value and load.We also got axial length increment of supporting structures' while they were under the force.By building the experiment devices to model the condition while straight pipes' and axial bent pipes' tractors are passing hinders,we researched the condition while tractors are passing hinders in straight pipes and the tract force changing situation in oil and sand medium.Finally,we got the tract forces changing curves under various sorts of hinders.By doing these experiments,we validated the results of theory calculate and simulate tests. |
PDF Full Text Request