Research On Grinding Parameters And Grinding Mode Optimization Design Of Manual Grinding Machine

Rail grinding is a common rail maintenance method on railway sites,which can timely repair various rail damages and ensure the safe operating environment of trains.As an important way of rail grinding,the manual grinding machine has several advantages,such as the flexible upper and lower tracks,the wider grinding angle,and the capability of repairing in local areas.However,the grinding efficiency of manual grinding machine is relatively low,and its grinding quality is difficult to guarantee.For the purpose of improving the grinding efficiency and quality,it is thus necessary to systematically study the key factors of the manual grinding machine grinding process,such as grinding parameters,grinding methods,grinding profiles,and grinding modes,etc.Through the preliminary on-site investigation,the problems existing in manual grinding machine were first summarized and analyzed.Then,the optimum parameters of manual grinding machine were obtained through experiments.Combined with the grinding target profile and the measured profile on site,the grinding profile was designed with the goal of reducing the grinding amount.Finally,a grinding mode design software of rail grinding machine was developed based on the optimal grinding parameters and the designed grinding profile.The main conclusions of the paper are as follows:(1)With in the range of parameters that could be used for manual grinding machine,with the increase of grinding pressure,the single-pass grinding amount of the grindstone increased,as well as the grinding heat.When the grinding pressure was greater than 900 N at the rail crown,greater than 700 N at the rail shoulder,and greater than 700 N at the gauge angle,burn began to appear on the rail surface.With the decline of feed rate,the grinding amount of grinding stone and the grinding heat rose.On the premise that the selected grinding pressure could ensure the grinding quality,when the feed rate was less than 1 km/h at the rail crown,less than 2km/h at the rail shoulder,and less than 2km/h at the gauge angle,burn began to appear on the rail surface.Considering the influence of the grinding quality and efficiency,the optimal grinding parameters are as follows: the grinding pressure at the rail crown is 900 N,with feed rate of 1 km/h;the grinding pressure at the rail shoulder is 700 N,with the feed rate of 2km/h;and the grinding pressure at the gauge angle is 500 N,with the feed rate of 3km/h.(2)With the increase of grinding times,the grinding amount of the grinding stone in a single pass showed a decrease trend,while the grinding heat rose,and the surface of the rail gradually altered from no white etching layer to a discontinuous white etching layer.As the further increase of grinding times the surface of the rail began to cover a continuous white etching layer with uniform coverage,and the surface roughness decreased.The test results under different grinding methods showed that: increasing the single-pass grinding amount of the grinding stone in the first few passes and reducing the grinding amount in the last pass could improve the grinding quality and the grinding efficiency.Furthermore,the white etching layer could be avoided by reducing the grinding times.(3)The wheel-rail contact problem under different wheelset lateral displacements could be converted to a single-objective,multi-variable,multi-constraint,nonlinear mathematical optimization problem.Aiming at improving the wheel-rail conformal contact,the rail grinding profile was optimized by using sequential quadratic programming algorithm.The newly designed grinding profile could ensure the wheel-rail contact performance while improving the grinding efficiency.(4)A grinding mode design software of the rail grinding machine was developed on the MATLAB software platform,which could automatically design the grinding profile and the grinding mode of the manual grinding machine,improving the grinding efficiency of the manual grinding machine on site.The developed software could also evaluate the quality of the rail profile after grinding,which ensured the grinding quality and provided scientific guidance for the on-site manual grinding machine.