Research On Workpiece Fixture And Thread Parameter Processing Of Thread Measuring Instrument

Threaded parts are widely used in many fields,such as the machinery industry,the automotive electronics industry and the aerospace industry.Since the interchangeability,reliability and sealing performance of threaded parts is mainly affected by the machining accuracy of threaded parts,the accuracy testing of threaded parts has become an important part of measurement technology.There are many ways to measure the accuracy of thread parts.However,the traditional methods of thread detection,such as pass / stop check,three-pin method and micrometer method,can not usually measure the specific value of the thread geometry,or can only measure some geometric parameters of the threaded parts,and the measurement results are easily affected by human factors,detection accuracy and measurement efficiency is not high.In this paper,a set of matched thread workpiece fixtures was developed based on a new type of contact thread gauge independently developed by the research group.The sampling data processing method of the threaded parts of the new contact thread gauge software data processing system was also studied.According to the characteristics of the new type of automatic measurement of the contact thread measuring instrument,the external thread workpiece fixture and the internal thread V-shaped workpiece fixture are developed.External thread workpiece jigs include external thread top workpiece clamps for clamping with center holes and external threaded V type workpiece clamps for clamping without center holes.The finite element simulation analysis of the vertical plate and thimble parts of the workpiece fixture with outer thread center and the finite element simulation analysis of the pedestal guideway of the V-shaped workpiece fixture with internal thread are carried out.The processing method of the sampling data of the threaded part of the new contact thread gauge software data processing system is studied.The sampling dataobtained by scanning the surface profile of the screw part of the novel contact type screw measuring instrument comprises the sampling data of the crest section of the thread part,the sampling data of the tooth side section and the sampling data of the tooth bottom section.The geometric parameters,such as the pitch,the middle diameter and the tooth shape angle,can be calculated by the linear fitting according to the sampling data of the lateral section of the tooth.The big diameter and the small diameter of the screw part are calculated by using the sampling data of the tooth top and the sampling data of the tooth bottom.In this paper,a new type of contact thread measuring instrument is used to measure the sampling data of the axial misalignment and the axis tilt of the screw part when the screw part is measured.According to the characteristics of axis untilt and axis tilting of thread parts,the sampling data processing method of thread parts axis is given,and the sampling data processing method of thread parts axis tilting is given.The sampling data processing method of threaded parts is realized through Matlab software programming to read,segment and match the simulated sample data of threaded parts,and to calculate all geometric parameters of threaded parts.The simulation sampling data of thread parts are generated by Matlab software,and the processing method of sampling data of thread parts is analyzed and verified experimentally.The reliability and rationality of the sampling data processing method for thread parts are further improved.