Research And Practice On Monitoring Method For Grinding Quality In Gear Profile Grinding

Gear is a crucial component for transmitting movement and power,and high-performance gear manufacturing is an important support for national economic development and defense construction.Nowadays,"hobbing-heat treatment-grinding" has become the main technology of gear manufacturing,among which grinding process determines the final precision level and surface quality of gears.Gear grinding can be divided into generating grinding and profile grinding.Gear profile grinding is the first choice for machining small batch of high performance gears or large size gears.Therefore,it is of great significance to study the material removal mechanism and grinding quality of gear profile grinding.However,the traditional grinding models are not suitable for gear profile grinding due to the differences in the aspects of wheel geometry,grinding grain cutting path,and chip geometric.At the same time,the quantitative calculation theory of wheel wear,the influence of wheel wear on the machining process and grinding quality are all unclear.There is no clear theoretical guidance for setting of wheel dressing interval,reducing production efficiency and the workpiece quality.In addition,the gear accuracy is only measured on the machine after being shutdown,and the tooth surface topography and tooth surface residual measurement is required to cut teeth.The measurement process is complicated,and the gear can not be adjusted again,and it is difficult to adjust the production process in real time.Therefore,it is necessary to carry out the research on the on-line monitoring of the quality of gear profile grinding.Aimed at gear profile grinding,this paper proposed the double beveled wheel wheel model by a fusion matrix,the chip geometric calculation and correction method,critical condition for different grinding stages based on measured grain parameters,gear error and topography calculation method considering wheel wear.Then,an online monitoring method of grinding quality was proposed based on the above models,and relevant test verification is carried out.The main contents are as follows:(1)Macro and micro geometric modeling method of double beveled grinding wheel considering wheel wear.Firstly,the macroscopic geometric model of the of wheel surface is established.Then the micro geometric parameters,including grain location,protrusion height,shape,and size are carried out.In addition,the wear ratio is defined according to the micro-geometric parameters of grains before and after wear,and the modified grinding ratio is proposed based on the material removal volume of grains,to reveal the wear performance of wheel from the perspective of grains.Finally,by measuring the wheel surface,the model was verified by the protrusion height distribution and surface roughness of the wheel.(2)The grinding force calculation and on-line monitoring method of gear profile grinding.Firstly,according to the micro model of wheel,the motion path of grinding particles is calculated,and the calculation and correction method of chip geometric parameters is proposed.On this basis,the critical conditions of grinding stage are derived based on the measured geometry of grains,and the grinding forces are calculated considering grinding stages.Then,the relatinoshiup between forces and spindle power is established to realize the force monitoring.Finally,experimental verification was carried out to prove the effectiveness of the calculation and monitoring method.(3)Calculation method of surface error and topography based on wheel wear.Based on the wheel wear calculation method,effects of wheel wear on the tooth profile curve are analyzed,and the influence of different wear parameters on the profile deviation,helix deviation are calculated quantitatively.As to the topography,the effect of material accumulation at plowing stage is considered.Then,for the grains in the cutting stage,through tooth surface and chip straightening,and matrix transformation,a unified cutting zone judgment method is proposed,and then the height elements in the cutting zone were replaced to realize the iteration of the tooth surface matrix.Finally,the calculation method of surface error and topography was verified by experiments.(4)On-line monitoring method of grinding quality.A method for measuring residual stress of gear tooth surface is proposed to reveal the distribution of residual stress on the whole tooth surface.In addition,the dynamic grinding force is calculated considering the wheel wear.On this basis,all the calculation methods and modeling techniques established above are applied to realize the on-line monitoring of grinding quality.Finally,the effectiveness of the monitoring method is proved by optimizing the trimming interval based on spindle power monitoring.