Design And Performance Test Of Deep Hole Straightness Measuring Device

Deep hole parts are widely used in production and life.Such parts have large length and diameter,and the processing process is more complicated,so it has a great influence on the axis straightness of the processed parts,while the inner hole straightness of deep hole parts directly determines the performance of the parts and affects the service life of the parts.At present,the existing methods for measuring the straightness of deep-hole parts have shortcomings such as poor measurement accuracy,complicated equipment operation,and poor environmental adaptability.In this paper,according to the measurement requirements of smoothbore gun barrels,we propose the optical axis method which is based on photoelectric detection to measure straightness,and a set of deep hole straightness measurement device is designed.The main research contents are as follows:(1)The optical axis method based on photoelectric autocollimator is proposed.According to the specific measurement requirements of artillery barrels,after comparing various straightness measurement methods,the optical axis method based on photoelectric autocollimator is selected as the straightness measurement.method,and proposes an evaluation algorithm combining the least squares method and the smallest area inclusion method to evaluate the straightness.(2)The technical scheme for straightness measurement of deep hole parts is designed,and it is proposed that the deep hole straightness measuring device should have the functions of automatic centering,stable walking,straightness measurement data acquisition and analysis and processing,and the structural form,main design parameters and work flow of deep hole straightness measuring device are determined.(3)The measurement error analysis is carried out for the measurement scheme adopted by the deep hole straightness measurement device,and it is determined that the installation error of the mirror inclination angle of the measurement unit and the centering accuracy of the device have a great influence on the straightness measurement.In order to improve the measurement accuracy of the deep hole straightness measuring device,in-depth analysis of the inclination angle error of the measuring unit mirror and the device centering error,respectively,the measuring unit mirror inclination angle measurement model and the device centering error measurement model are established.(4)The structural design of the deep hole straightness measurement device is carried out,and the measurement unit is divided into a mirror installation module and a photoelectric autocollimator installation module,and the two modules cooperate to complete the collection of the straightness measurement data in the deep hole;the structure of the centering unit is designed according to the principle of point centering,and the centering effect of the measuring device is realized by the cooperation of the conical block,steel ball,and supporting plate;in order to realize the compact design of the measuring device,the driving unit is placed in the center of the centering unit,The motor and the roller cooperate to realize the stable walking function of the measuring device.According to the control requirements,a control system is proposed,which uses the industrial computer as the software carrier of the upper computer and the electrical control cabinet as the hardware carrier of the lower computer.(5)The construction of the deep hole straightness measuring device was completed,and the mirror inclination angle determination experiment and the centering error experiment were carried out on the measuring device.All are within 5μm/m,and the maximum measurement error is 4.44μm/m,which meets the design requirements.Through the above research,the optical axis measurement method based on the photoelectric autocollimator is proposed,and the deep hole straightness measuring device is developed,which is applied in the straightness measurement of the barrel sample,and the deep hole straightness measuring device realizes high-efficiency and high-precision measurement of the straightness of deep-hole parts.