Analysis Of Water Seal Characteristic Of Rock Drill Under Rotating Impact

In mining,due to the complex working conditions and harsh environment of the dynamic seal of the flushing mechanism of the hydraulic rock drill,the Y-type sealing ring between the brazing tail and the flushing head is not only affected by the combination of rotation and high frequency impact motion,but also by the lack of water lubrication.The leakage and early failure of the sealing ring are often observed.Also it is difficult to replace the seal,which has seriously affected the drilling equipment work efficiency.Therefore,it is very important to analyze and study the influence of impact velocity amplitude,rotation velocity,medium pressure and other factors on the sealing performance of dynamic seals,which is of great importance to the design optimization of seals and the improvement of sealing performance.In this paper,the sealing performance analysis and life prediction of Y-type water seal of drilling machine flushing mechanism are taken as the goal.The influence of multiple factors on sealing performance is analyzed.The key technical problems of water seal lubrication model,contact stress distribution,mises stress distribution,leakage variation and friction and wear life are systematically studied.The main research contents include the following aspects :(1)Finite element modeling : Based on the analysis of the sealing mechanism of Y-ring,the basic theory of finite element method is briefly introduced.The three-dimensional simulation model of Y-ring under variable speed impact and rotation is established by finite element software ABAQUS,and the practicability and reliability of the finite element model are verified by the experimental results provided by relevant literature.(2)Dynamic sealing performance of Y-ring : Combined with actual working conditions,the sealing performance of water seal of rock drill was simulated and analyzed.The influence of the impact velocity amplitude,rotation velocity and medium pressure on the maximum contact pressure,mises stress distribution and pressure distribution of the main and auxiliary sealing surfaces was studied by ABAQUS software.(3)Leakage : On the basis of in-depth study on the working characteristics of flushing mechanism of rotary impact drilling machine,based on the basic form of general Reynolds equation,the calculation formula of water film thickness and leakage of Y-ring seal contact interface under the condition of rotary impact combined motion in pure water medium is obtained.The effects of different fluid pressure,impact velocity amplitude and rotation velocity on leakage under variable velocity conditions were analyzed.(4)Analysis of wear characteristics : Based on the simulation results of the contact stress of the water seal of the flushing mechanism of the rotary impact drilling machine,combined with Archard friction and wear theory,the wear amount of the sealing ring under this condition is obtained.The effects of impact velocity amplitude,rotating speed and medium pressure on seal wear life were studied.Based on the above theoretical analysis and numerical simulation technology,this paper provides reference and guidance for the study of sealing performance,life prediction and design optimization of pure water seal of high pressure water flushing mechanism of rotary impact rock drill.