| Gears are the key basic parts of many equipment,and their processing quality is of great significance to improve the performance of equipment in various industries.Compared with the traditional gear hobbing,shaping and other tooth cutting processes,the gear skiving has significant advantages such as high efficiency,high precision and green dry cutting,and is gradually becoming the preferred process for processing complex precision inner ring gear on industrial robot reducers,automobile gearboxes,and aero-engine reducers.However,there are theoretical defects in the gear skiving technology that lead to accuracy attenuation due to the conjugate mismatch between the cutting edge and the tooth surface after tool regrinding,which seriously restricts its popularization and application.In this paper,by studying the intersecting shaft skiving meshing theory under the offset condition of the production wheel,a design method of cylindrical skiving tool without structural relief angle is proposed.The specific research content is as follows:(1)A mathematical model of bias skiving process based on intersecting shaft conjugate theory is established.According to the spatial meshing theory and gear differential geometry,a mathematical model of intersecting shaft skiving meshing with double degrees of freedom was established.From the malleable characteristics of the involute helix surface,the skiving meshing condition and the conjugate tool surface under offset conditions are derived.Taking involute tooth tooth machining as an example,a biased conjugate tooth machining theory without conjugate mismatch is proposed,which can effectively solve the problem of accuracy decline after regrinding of conical skiving tools.(2)The design method of unstructured relief angle skiving tool without theoretical error is proposed.The mathematical model of skiving tool with structural rake angle is established,and the cutting edge shape is constructed based on the intersection of rake face and conjugate surface.The flank of the tool was constructed by spiral surface,and the interference between the back rake face and the conjugate surface was verified.Based on the envelope method,the exactness of the theoretical model of the tool is verified,and the sharpening process of the unstructured relief angle skiving tool is proposed.(3)The forming process of tooth flank using unstructured relief angle skiving tool was studied.According to the development motion relationship between the tool and the tooth flank,the kinematics model of skiving machining under offset conditions was established,the mapping relationship between tooth machining parameters and the edge sweeping trajectory was analyzed,and the bias skiving machining and forming process of unstructured relief angle skiving tool was clarified.By establishing the model of time-varying working angle of the cutting edge of the tool,the change law of cutting angle of the unstructured relief angle skiving tool is revealed.The cutting experiment shows that the gear machining accuracy of the unstructured relief angle skiving tool designed in this paper can reach GB 7,and the cutting interference of the back rake face will not occur during the skiving process.Compared with traditional conical skiving tools,the sharpening process of unstructured relief angle skiving tools is simple,and the tool regrinding thickness is increased from5 mm to 11 mm,and the tool service life is increased by more than 1 times.The research content of this paper further enriches the skiving processing theory of cylindrical gears,which can provide a theoretical basis for the design and manufacture of new long-life skiving tools,and has a good engineering application prospect. |
