| The service life of wearing parts of drilling pump plays an important role inperformance of drilling pump, directly affecting drilling efficiency. Drilling pumppiston holds the very great proportion in the wearing parts, so the study of drillingpump piston is necessary. The failure forms of drilling pump piston are mainlyabrasive wear and crushed. The influencing factors of drilling pump piston failure arethe friction heat, the clearance between the piston and cylinder liner, mud, the qualityof cylinder liner, pump pressure and speed. In order to make a thorough research onthe piston of drilling pump, the working principle of BW-160type drilling pump isanalyzed in this paper. Through the movement of the piston, the piston displacementand velocity are deduced and static and dynamic forces are analyzed for the pistoncup.Bionic stripe shape piston is designed and tested about wear resistant sealingperformance on the basis of the bionic non smooth wear theory in this paper.Experimental results show that the fringe of reasonable structure can improve theservice life of the piston and unreasonable structure will reduce the service life of thepiston. The service life of bionic piston is increased by78.7%, and sometimesreduced by63.7%.In order to optimize structure parameters of bionic pistons, usingmethod of analysis of variance analysis the influence of various factors on the servicelife of the piston, and regression equation is obtained through the regression analysisof multivariate orthogonal polynomials. The range analysis of9kinds of bionic pistonshowed that the primary and secondary factors are A B, and the optimal combinationis A2B2.The optimal piston stripe width is4.5mm, and the fringe spacing is5.0mm.According to the test results, the contact area of the piston and the cylinder hasvery big effect to the service life of drilling pump piston. In order to demand theoptimal contact area, proof tests have been done. The test results show that theoptimal contact area of the piston and the cylinder is73.5%.In order to find theoptimal parameters of bionic piston structure, the number of fringes bionic pistonsurface is studied further. The bionic piston force was analyzed by ABAQUS. Thenumber of reasonable fringes is3, and it is made to test. The average service life of bionic piston is81.3h, and the service life is increased by78.7%.The optimalstructural parameters of the bionic piston are that the number of stripes is3, the stripewidth is3, and the fringe spacing is3.In order to study wear and sealing performance of bionic piston, the movementof standard piston and bionic piston is analyzed by the finite element analysissoftware ABAQUS. Through the comparative analysis of misses stress at the root ofpiston and contact stress at the lip of piston can be seen, the contact stress at the lip ofbionic piston is large, and misses stress at the root of bionic piston is relatively small.This kind of force structure is beneficial to increase the sealing of piston lip, andreduce wear of piston root. Wear-resistant sealing mechanism mainly includes3aspects: Non-smooth structures of the bionic piston surface change the stresscondition of the piston; The stripe structure of bionic piston can store lubricatinggrease; The grain can be stored in the stripe structure of bionic piston. |
