Fengshou Zhang

Metal Flowing of Involute Spline Cold Roll-beating Forming

The present research on involute spline cold roll-beating forming is mainly about the principles and motion relations of cold roll-beating, the theory of roller design, and the stress and strain field analysis of cold roll-beating, etc. However, the research on law of metal flow in the forming process of involute spline cold roll-beating is rare. According to the principle of involute spline cold roll-beating, the contact model between the rollers and the spline shaft blank in the process of cold roll-beating forming is established, and the theoretical analysis of metal flow in the cold roll-beating deforming region is proceeded. A finite element model of the spline cold roll-beating process is established, the formation mechanism of the involute spline tooth profile in cold roll-beating forming process is studied, and the node flow tracks of the deformation area are analyzed. The experimental research on the metal flow of cold roll-beating spline is conducted, and the metallographic structure variation, grain characteristics and metal flow line of the different tooth profile area are analyzed. The experimental results show that the particle flow directions of the deformable bodies in cold roll-beating deformation area are determined by the minimum moving resistance. There are five types of metal flow rules of the deforming region in the process of cold roll-beating forming. The characteristics of involute spline cold roll-beating forming are given, and the forming mechanism of involute spline cold roll-beating is revealed. This paper researches the law of metal flow in the forming process of involute spline cold roll-beating, which provides theoretical supports for solving the tooth profile forming quality problem.

Analyze and Correct Model for Machining Involute Spline

The rolling technic of involute spline has many advantages. This method can increase the production efficiency, has no cutting, can improve the metal structure of machining surface to increase the quality of surface and prolong the life of product, so the technic is used extensively in the industry of automobile and tractor. The design model of spline outline is built according to the formative theory of equidistant spiral surface by means of meshing principle of involute spline, roller is manufactured and machining spline is test according to the model. The correction of spline outline is accounted by means of measuring the outline of spline in three-coordinates measuring machine and comparing the measuring data and the data of ideal involute spline. The spline is remachined in corrected roller and ideal spline shape is gotten.

Research on Bearing Life Prediction Based on Three Parameters Weibull Distribution

To those bearings which are used in the field of aerospace, when doing the test of bearing life of the high precision and high reliability, the small sample datas and non-failure phenomenon will occur. To be able to accurately predicting the life and reliability of bearing, the paper analyzes geometry and physics meaning of three parameters of Weibull distribution based on the three parameters Weibull distribution theory. And Builds the Weibull likelihood function. According to Newton iterative method, the left of equations set is expansed to make it transformed into linear equations set. Then iterative calculate the parameters estimate value. So obtain bearing reliability model of three parameters Weibull distribution. Failure statistics shows that the mathematical model of the paper can predict the actual life of bearing.

Study on Laser Triangulation Measurement Principle of Three Dimensional Surface Roughness

The basic principle of three-dimensional surface roughness laser triangulation has been analyzed in this paper, Light-path diagram and optical geometric relationship of direct-type and symmetric oblique-type triangulation measurement is studied, the mathematical model of Surface micro-height information analysis is given. Resolution of direct-type and symmetric oblique-type triangulation measurement is compared both qualitatively and quantitatively. At last, the Application of laser triangulation method in Three-dimensional surface roughness measurement is analyzed.

Numerical simulation of cold rolling involute spline forming

Using explicit central difference algorithm, the numerical simulation of cold rolling involute spline is accomplished by finite element method. The metal flowing law and the stress and strain field of involute spline are presented. Comparing and contrasting simulation results with experimental results, some conclutions can be obtained as follow. Metal flowing accords to minimal damp law in the process of cold rolling. To improve formation precision, the dentiform errors of spline caused by elastic deformation should be corrected. And the correcting method is presented in this paper by enlarging the outer diameter of workpiece designed with the experiential method. It is helpful for improving cold rolling system design and studying ulteriorly the forming mechanism of cold rolling involute spline in quantitative analysis.

Research on Light Pen Measuring System

Under the current situation of the rapid development of major equipment and technology, the research on measurement equipment, suitable for requirement of large-size application, is urgency and important. A light pen measuring system based on binocular stereo vision measurement principle is researched. The composition and working principle of the system are analyzed. Subpixel marginal fitting method is adopted to obtain the precise position of the center coordinates of the point of the coded marks. A mathematical model of the camera is Established, and the corresponding relations between the three-dimensional coordinates of the mark points in space and the two-dimensional coordinates of the same points in the image are deduced. In order to improve the speed and accuracy of image matching, the light reflection coded mark stickers are adopted as the marks of the light pen for imaging. The research on the key technologies of the light pen measuring system provides a theoretical basis for the further striking of three-dimensional coordinates of the space point, for the 3D reconstruction of the space model, and for the realization of software technology .

Development and Trend of Ultrasonic Techniques in On-Line Detection for Strip and Plate’s Internal Defects

For meeting the requirements of high-precision and high-speed in on-line detection for strip and plate’s internal defects, in the paper, based on elaborating methods and principle of conventional ultrasonic testing, the research status of traditional ultrasonic testing technology and non-contact ultrasonic testing techniques, there analysis and discuss the problems and causes in the process of detection. In the end, the trend of development is given.

Research and Correction on Cone Angle Effect of CBCT

The cone angle effect of CBCT system and affecting reconstructing slice are discussed. The CC-FDK algorithm is introduced. The redundancy data is not disposed accurately in FDK algorithm. The thesis puts forward a weighting projection method based on cone angle and distance to center plane. The method compensates the information of projection unused in FDK algorithm. The simulation model is scanned and reconstructed. The result indicates that this method can extend the cone angle of scanning.

Research on Grinding Model of Roller for Manufacturing Involute Spline

The paper studies the grinding process of cold roller. The shape of grinding wheel, the arc radius of grinding wheel, the motion trajectory of wheel center and the grinding force are analyzed. The mathematical model is established. The cold rolling experiment shows that the analyses and formula deduced in this paper are correct. It provides theoretical basis for designing and manufacturing roller and provides the mathematical guidance for making process parameter and designing grinding machine.

Research on tooth surface integrality of cold rolling spine

Based on the experimental research, metal microstructure evolvement, remnant stress distribution, hardness distribution and tooth surface quality, tooth surface integrality of cold rolling spline are studied in this paper. Since the cold rolling spline is formed by roller rolling workspace, the experimental research results indicate that there are many advantages for tooth surface integrality. The grain is refined. The dislocation density is increased evidently. Metal microstructure canpsilat be cut off during cold rolling process and it is eventually dragged into strip fibrous structure. Hardness of spline in surface layer metal is also improved markedly. Because there are no traces of metal tearing on tooth surface, the surface glabrousness is better. Using the experimental results, the distribution regularity of remnant stress is obtained in the direction of tooth surface and tooth depth. Also it is found that metal flowing accords with minimal damp law in the process of cold rolling. Some conclusions are obtained from the research results. Metal microstructure surface layer and remnant stress distribution are reformed. Strength of spline and tooth quality are improved. So tooth surface integrality is enhanced markedly. All in all, mechanism of improving tooth surface integrality of spline formed by cold rolling machining method is revealed in this paper.