Research On The Shape Error Of Large Shaft Parts By Three-point Method

The driving axle housing of heavy truck is an important component of the automobile,its shape and position error directly affect the service life of the car.Aiming at the problem of low manual measurement accuracy and large labor intensity of large shaft parts such as heavy truck drive axle housing,a laser displacement sensor rotation measurement scheme based on three point method this paper was proposed.According to the characteristics of heavy truck axle housing,an automatic measuring device is designed,and a data acquisition and processing system is developed.The specific research contents are as follows:(1)The background and significance of the research are expounded,the current situation of the measurement of shaft parts at home and abroad is analyzed and the main content frame of this paper is given.(2)A mathematical model of three point method of roundness error separation is established.The cause of harmonic suppression in the algorithm and the method of avoiding harmonic are analyzed and the influence of sampling frequency,sampling length and other parameters on measurement error is studied.Moreover,the accuracy of the angular position error of the sensor and the separation algorithm of the three point method for roundness error are analyzed.(3)According to the structural characteristics and measurement scheme of the heavy truck driving axle housing,the measuring device is designed and the measurement platform is established.The design platform includes laser displacement sensor,KK module and RS-232 communication module.A data automatic acquisition and a processing system are developed based on the software of Visual Studio2010,The system can analyze and display the measurement results in real time.(4)The assessment algorithm of roundness error is studied.The assessment algorithm of roundness error contains the least square circle method,the minimum region method,the maximum inscribed circle method and the minimum circumscribed circle method.Based on the above research,a matrix mesh roundness error search algorithm is proposed,which can quickly obtain the results of four evaluation algorithms and simulation results show the effectiveness of the proposed algorithm.Through the design of the measuring device,the measurement of the shape error of the large shaft part is realized and the measurement conforms to the requirements of precise measurement.