The tooth surface of logarithmic spiral bevel gear is a complex spatial curved surface shape, which makes its machining process more difficult than that of general bevel gear. During the processing of logarithmic spiral bevel gear processed according to the generation method, the processing parameters of the machine tool should be adjusted according to the generation principle to process the large wheel, and then the small wheel should be cut according to the conjugate principle of logarithmic spiral bevel gear. In this way, the actual machined tooth surface of logarithmic spiral bevel gear has a certain machining error with the theoretical tooth surface, that is, the tooth surface deviation of logarithmic spiral bevel gear. Make the actual meshing point of the tooth surface deviate from the theoretical meshing point, and the meshing characteristics of the actually processed logarithmic spiral bevel gear pair deviate from the theoretical design requirements, which affects the actual meshing transmission of the logarithmic spiral bevel gear, and the ideal gear pair can be obtained only by trial cutting for many times.
With the rapid development of spiral bevel gear processing and detection technology, spiral bevel gear tooth surface detection has developed from the traditional contact mark inspection to the inspection of tooth surface geometry and accuracy. In order to improve the tooth surface accuracy of logarithmic spiral bevel gear and reduce the tooth surface error, the geometric structure of the actual machined tooth surface must be consistent with the theoretical tooth surface. The most economical and applicable method is to use laser scanning equipment to collect discrete data points, which can not only reconstruct the tooth surface of logarithmic spiral bevel gear, but also calculate the meshing points and analyze the difference surface between the real tooth surface and the theoretical tooth surface, so as to obtain the machining error of logarithmic spiral bevel gear, and further take effective measures, Improve the machining accuracy of logarithmic spiral bevel gear. Difference surface is a kind of topological surface, which is an important tool to study contact problems. Difference surface is essentially an expression of the distance between elements in the functional space of logarithmic spiral bevel gear tooth surface corresponding to the functional space of machine tool machining parameters.
1.Based on the data points of logarithmic spiral bevel gear tooth surface collected by 3D laser scanner, the error of reconstructed real tooth surface and theoretical tooth surface is analyzed. Through the difference surface analysis tool, the theoretical tooth surface data points and real tooth surface data points of logarithmic spiral bevel gear are obtained, the normal deviation of tooth surface is calculated, and the difference surface equation is established and solved.
2.In order to correct the machining parameters of the machine tool, the difference surface results are analyzed and adjusted to minimize the distance and direction between the theoretical tooth surface and the real tooth surface of the logarithmic spiral bevel gear, and achieve the expected ideal effect, so as to make the contact analysis of the tooth surface and the correction of the machine tool parameters for the next step, It provides a basis for improving the tooth surface machining quality and machining accuracy of logarithmic spiral bevel gear.
The theoretical real tooth surface is regarded as obtained by superimposing a layer difference surface on the theoretical tooth surface and flattening it on the plane. Because the deflection of the plane is very small, it can be fitted with high precision in the range of the theoretical whole tooth surface as long as it is on the quadratic or cubic model. The machining accuracy of real tooth surface and the adjustment of machining parameters of machine tool can be evaluated by using the properties of difference surface. The difference surface of logarithmic spiral bevel gear refers to the free-form surface formed by the difference between the spatial coordinate value of the measurement point along the unit normal direction of the tooth side of each measurement data point and the spatial coordinate value of the corresponding theoretical point, that is, the difference surface between the theoretical tooth surface and the real tooth surface of logarithmic spiral bevel gear. In the actual gear machining process, due to the influence of various factors, there is always a difference between the theoretical tooth surface and the real tooth surface. In order to adjust the machine tool parameters, reduce the deviation and improve the machining accuracy, the difference surface error of logarithmic spiral bevel gear must be analyzed. Firstly, the data point coordinates of the theoretical tooth surface and the real tooth surface should be calculated.