Research On Concave Error Mechanism Of Multi-source Coupling And Shaving Optimization Methods

Shaving processing is an efficient process in the manufacture of gear finishing.It is widely used in the gear production of machine tools,automobiles,ships,aerospace and other industries.It has the advantages of high efficiency,low cost,strong adaptability and convenient adjustment.However,shaving concave error of tooth profile is a long-term problem during the gear manufacturing.It not only affects the tooth flank accuracy as well as the transmission characteristics,but also limits the application of shaving in highprecision occasions.In this paper,the formation mechanism of shaving concave error is studied from the aspects of contact ratio,machine tool motion and alignment error.And the shaving processing optimization methods(including the optimization design of the shaving cutter,the optimization of machine tool parameters and the displacement compensation of the alignment error)are proposed.Also,the non-equal edge shaving cutter is designed to reduce or eliminate the concave error,which has important theoretical and social benefits for promoting the development of the gear industry and achieving efficient processing of shaving tooth.The main contents and innovations work of this paper are as follows:Considering the existence of the chip pocket,the cutting edge of the shaving cutter,and the time-varying state of the gear tooth surface during the allowance removal,a shaving processing analysis model is established,which can accurately reflect the actual shaving process.The algorithm of shaving processing characteristics is proposed,which provides a theoretical basis for the optimal design of the shaving cutter.The change of shaving parameters is attributed to the change of contact ratio.The effect of contact ratio on the shaving processing characteristics is studied,the relationship between the contact ratio and the concave error is defined,and the formation mechanism of the concave error of the shaving tooth shape due to the contact ratio is revealed.The results show that increasing contact ratio can reduce concave error,however,excessive contact ratio will cause the transmission performance to decrease significantly,and the large vibration will occur,which will affect the accuracy of the tooth surface.The shaving cutting force model is constructed,from which the shaving cutting force and cutting speed expression are derived.The influence of the machine tool motion(radial feed motion,axial feed motion and spindle rotation)on shaving process is studied,and the variation law of the pitch circle position is analyzed.The results show that the radial feed motion is the most important factor that affecting the shaving effect,and its influence on the shaving processing characteristics is analyzed.The validity of the model calculation is verified by the shaving experiment.The relationship between the machine tool motion and the concave error is explained as well.The shaving machining model is established,in which the alignment error is introduced in the original geometric coordinate system,driving to a new coordinate transformation,and the compensation displacement caused by the alignment error is deduced.Based on this,the theoretical transmission error,the transmission ratio and the shaving depth error are derived.The effect of shaving alignment error on shaving processing is studied.Adjusting the machine tool according to the compensation displacement can control the installation error reasonably,which can effectively improve tooth flank accuracy and processing efficiency.Considering the above analysis,the shaving processing optimization methods(including the optimization design of the shaving cutter,optimization of the machine tool parameters and the displacement compensation of the alignment error)and the design of non-equal shaving cutter is proposed.Shaving experiments verified the correctness of the shaving process optimization.Under certain specific shaving parameters,when the shaving processing characteristics cannot be further satisfied,the non-equal shaving cutter design is proposed by combining negative displacement shaving and balance shaving principles.The results show that the non-equal shaving cutter makes the shaving process more stable,and the reliability of the non-equal shaving cutter is verified,which provides a new technical solution for eliminating the concave error of the shaving tooth profile.