Meshing Principle And Geometric Contact Characteristics Of Noncircular Face Gears With Intersecting Axes

Non-circular gear is a new model of spatial variable ratio gear mechanism,Integrated transmission between two shafts can be realized.It combines the transmission characteristics of non-circular gears and face gears,and has outstanding advantages such as simple closed conditions,large overlap,good interchangeability and convenient installation.It has broad application prospects in the fields of vehicles,robots,aerospace,instrumentation and agricultural machinery,etc.However,the current meshing theory is limited to the special orthogonal shaft structure,which can not guide the design of noncircular gears with arbitrary intersecting axes,which greatly limits the application of this gear.It is of great theoretical significance to establish a systematic meshing theory of noncircular gears.A general design method of closed noncircular face gears based on Fourier series is proposed to meet the demand of any periodic variable speed transmission.In this paper,the enveloping principle of non-circular face gears with intersecting axes in gear shaping is studied,and the mathematical model of tooth surface of non-circular face gears with intersecting axes is established.The generating principle of gear shaping with intersecting axes and the correctness of the mathematical model of tooth surface are verified by machining simulation.On the basis of tooth surface mathematical model and gear TCA theory,the tooth surface contact mathematical model of non-circular face gear with intersecting axes is established,and the tooth surface contact trace of non-circular face gear under ideal installation condition is calculated.The contact characteristics of different gear teeth are compared and analyzed,and it is found that the shape of tooth surface contact trace is greatly influenced by the time-varying direction diameter.Furthermore,the mathematical model of tooth surface contact of non-circular face gears with intersecting axes with installation errors is established,and the instantaneous contact points of all tooth surfaces of non-circular face gears with different installation errors and design parameters are solved by using programming software,so as to obtain tooth surface contact traces.By comparing and analyzing the influence of different factors on the contact state of tooth surface,it is found that when the important official angle error and offset error are positive or the axial error is negative,the contact trace of tooth surface of non-circular face gear shifts to the inner diameter end,on the contrary,the contact trace of tooth surface shifts to the outer diameter end;Under the same installation error,the offset of contact trace of non-circular face gear tooth surface increases with the increase of shaft intersection angle.At last,the non-circular face gear transmission device with intersecting axes was designed and manufactured,and the gear rolling test was carried out,and the actual contact marks of the non-circular face gear were obtained.Because of the machining and installation errors,the edge contact appeared on the tooth surface,but the overall contact marks were basically consistent with the theoretical analysis results,which proved the correctness of the contact model and analysis results of the non-circular face gear with intersecting axes.