Research On Three-coordinate Measuring Method Of Non-circular Gear Error

As one of the most extensively used transmission forms,gear transmission has been widely used in all walks of life.With the advancement and development of science and technology,the unique transmission characteristics of non-circular gears have captured the attention and weight from scholars.Due to its starting late,complex shape,and various types of non-circular gears,a complete measurement theory is not yet formed at home and abroad,meanwhile,the error measurement standard remains unclear,what's more,current measuring instruments only apply to a few specific indicators,all of these problems have limited the precision transmission and wide application of non-circular gears.Therefore,according to the non-circular gear formation principle is different from the characteristics of cylindrical gears,In this paper,a new measurement method is proposed based on the research and establishment of the error measurement project applicable to the non-circular gear,furthermore,it is of great theoretical significance and practical value to establish the error accuracy grade evaluation system.The object of this study is the measurement of non-circular gear,and the measuring method of non-circular gear error based on the three coordinate measuring machine is proposed,which uses a three-dimensional probe to detect the tooth profile of a non-circular gear to obtain a measurement point.Besides,a non-circular gear error indicators is calculated in order to evaluate the accuracy of a non-circular gear.Firstly,according to the method and principle of tooth profile formation of non-circular gears,the data points of the tooth profile of non-circular gears are obtained by numerical calculation.The optimal fitting method is used to curve fitting the discrete data points to obtain the equation of the theoretical tooth profile curve,which provides theoretical values for subsequent error calculations.Secondly,the error items of the non-circular gear are established by studying the causes of the non-circular gear error and analogizing the error item classification of cylinder gear and the principles of the measurement error project.With reference to the establishment and calculation methods of the accuracy standard for small-modulus involute cylindrical gears,certain error items and accuracy indexes of non-circular gears have been established,and a calculation method for the accuracy class of non-circular gears has been formulated.Finally,taking the elliptical spur gear as an example,the three-coordinatemeasuring machine was used to measure the tooth scanning of the elliptic gear,select the probe,plan the measurement path,compensate the radius of the measuring end,and measure the data value of the measuring points on the gear tooth profile.Moreover,the curve fitting method is used to fit the tooth profile curve of these collection points and the error of the measurement items of the non-circular gear is calculated.After the above research on the subject,a new method for measuring non-circular gears was adopted,the feasibility of this method is determined by means of practical measurement,which provides theoretical reference for the measurement of non-circular gear in the future.