Research On Internal Leakage And Hydraulic Clamping Force On Piston Of Impact Mechanism Of Hydraulic Rock Drill

Hydraulic rock drill is energy-efficient drilling equipment specifically designed for exploration, surface and underground mining, railway tunnel construction, utilities construction and so on. During the process of drilling, the core component of hydraulic rock drill-- impact mechanism, due to the impact of high-speed reciprocating motion of the piston and other reasons, often appears internal leakage and the piston radial imbalance, which, lightly, can reduce the performance and the life of the impact mechanism, or severely lead to completely ineffective. In order to reduce the internal leakage and the probability of hydraulic locking of the piston of impact mechanism, the paper has researched the internal leakage of the impact mechanism and the hydraulic clamping force on piston, which are as follows:(1) Based on the working principle of the impact mechanism of hydraulic rock drill and the movement law of the piston, the piston kinematics parameters were designed under the given end piston velocity and frequency and other parameters, which result in a mathematical model of periodic and transient internal leakage.(2) The simulation analysis was carried out with the mathematical model in MATLAB, concluding the influence rule on the clearance leakage with the single factor such as the system pressure, height, length of sealing gap, and providing the basis for factor level values of subsequent orthogonal test.(3) Based on the computational fluid dynamics(CFD) theory, the influence on the period clearance leakage, by the method of orthogonal test, was simulated and analyzed under the condition of mutual influence of various factors in FLUEN T. Compared with the calculation of mathematical model, the reasonable range of the clearance height, length of sealing gap was obtained.(4) Comparatively analyze the distribution of pressure and velocity in the gap flow field and the influence on the size of the clearance leakage by the different structure of the groove on cylinder wall. Analyze the clamping force on piston, under different motion conditions, when piston eccentric and forming a cone structure along the processing error. The influence rule of hydraulic clamping force on the piston was analyzed as well in different groove. Consider the effect of leakage and hydraulic clamping force and processing errors for performance of impact mechanism, obtain the appropriate structure parameters of impact mechanism, which has a certain practical significance for structural design of impact mechanism.