Experimental Study On Improving Surface Integrity And Service Performance Of Gears By Vertical Cross Spindle Mass Finishing

Gear pair is a kind of typical friction parts.There are sliding friction on the surface of the two teeth during the working process and the magnitude and the direction of the sliding friction are constantly changing.Therefore,the surface quality of the gears have a significant impact on it’s performance and service life,especially for the surface quality of tooth profile of gears.Barrel finishing has the characteristics of once the parts are clamped,it can be achieved all surfaces are processed at the same time,comprehensive improvement of surface integrity characteristic parameters,low processing costs and high processing efficiency etc.This paper is based on researching and developing new technology which is suitable for large module gears finishing.The performance of the gears is improved and the fatigue life of the gears is prolonged by means of optimizing the surface quality and improving the surface integrity of the gears.Our team have proposed a new method for gear finishing,which was called "vertical spindle gear barrel finishing method".In this paper,we have a in-depth and systematic study on the gear tooth surface uniformity,the surface integrity,the service performance after processing and so on.First of all,under the premise of consulting a large number of relevant literature,the main factors affecting the performance of gear are listed,and the various gear finishing methods commonly used at home and abroad are introduced.On the other hand,the characteristics and the scope of application of existing gear barrelling methods are compared,and clarifies the core content and research methods of this paper.Secondly,EDEM software has been used to simulate the whole machining process.It is concluded that the gear deflection angle and the drum speed have a great influence on the magnitude of the working force and the flow velocity of the particles.And then it is possible to speculate that the gear tooth surface uniformity and processing quality are significantly influenced by them.At the same time,the statistical software JMP and central composite experimental design method have been used to design the experimental scheme.Take the roughness as a measure,which act as a response target to evaluate the uniformity of the machined tooth surfaces.The experimental results show that after barreling,the tooth surface roughness Ra value can be reduced from about 0.7μm to about 0.2μm on the basis of gear grinding.And the standard deviation of roughness of the tooth top and tooth root are both less than teeth grinding after barreling.Gear deflection angle,drum speed,processing time and other major processing parameters have a significant impact on processing quality of the tooth surface.And then,on the basis of the previous research,we have a further study on the surface integrity of the gear before and after finishing(we aim at the main parameters that affecte the gear performance,including tooth surface roughness and micro-morphology,tooth surface layer microhardness,near-surface crystalline structure,residual stress state of the tooth root,etc.).Studies have shown that barrel finishing has a very significant effect on improving gear surface integrity.Based on the comprehensive fuzzy evaluation method,the fuzzy evaluation of the machining parameters on the surface integrity of the gear teeth is established.The conclusion is that the drum speed has the greatest influence on the gear surface integrity.Finally,the high-cycle fatigue test and the friction and friction and wear test of the gears before and after finishing were carried out.The results show that the flexural fatigue strength and abrasion resistance of the gears are improved after barreling,which demonstrate that it is helpful to improve the performance of gears by barrel finishing.In summary,this paper studies the gear barrel finishing method can effectively improve the surface quality of the gear,at the same time improve the gear’s surface integrity and thus it must contribute to improve the service performance.If it will achieve industrial applications in the future,that will provide a strong technical support to China’s high-end gear products.