Finite Element Contact Analysis And Experimental Research Of Spiral Bevel Gears

Spiral bevel gear is widely used in watercraft, aerospace, automotive and other industries for its big overlap ratio, high loading capacity, stability of transmitting, small sensitivity toward setting error and small noise. The spiral angle of spiral bevel gears of equal size and opposite direction makes the tooth shape, meshing characteristics and machining process complicated. The working performances of gears such as working life, bearing capacity, vibration, transmission noise and even the quality of the whole machinery, would be impacted by the meshing transmission precision, mechanical efficiency, contact stress of tooth surface, bending stress of tooth root, contact area of spiral bevel gears and so on.In this paper, based on the principle of virtual machining technology, the geometric models of spiral bevel gears were built by the three-dimensional modeling software; The static and dynamic meshing characteristics of the spiral gears under various working conditions have been studied by the finite element method, and the variation trend of the corresponding parameters has been obtained; According to the structural characteristics of the transmission spiral bevel gear box, a closed power measure system of test-bed was designed and established; The major performance parameters of spiral bevel gears were measured on the test-bed. The main contents can be summarized as follows:(1) Based on the virtual machining technology, the geometric models of spiral bevel gears were built. As the tooth surface of spiral bevel gear is so complicated, building its geometric model by analytical method becomes very difficult. However, the virtual machining technology can avoid deriving complicated geometry equations of spiral bevel gear, so it provides a perfect method for the modeling of spiral bevel gear. In this paper, the models of spiral bevel gears which close to the actual were generated. The modeling method was simulating the gear-process through virtual modeling technology in the three-dimensional computer modeling software.(2) The static/dynamic contact analysis of spiral bevel gears was analyzed. Based on the established geometric models, the static and dynamic contact analysis of spiral bevel gears under different load conditions were completed in the finite element analysis software. The variation of the parameters including the rotation angle, transmission error, contact force, the real coincidence degree, contact area, contact and bending stress of tooth root in different conditions of torque, were obtained in static analysis. In dynamic analysis, the results of the rotational speeds, transmission error, tooth contact forces, contact area and stresses of the tooth root are obtained in the different speeds and torques.(3) A closed power test bed of spiral bevel gears was designed and set up; The meshing performance parameters of spiral bevel gears were measured on the test bed. According to the structural characteristics, carrying capacity and testing requirements of the spiral bevel gears box, a closed power test system of spiral bevel gears was designed. This system can achieve loading process of the spiral bevel gears with different working conditions by an inverter system. The characteristics of the meshing spiral bevel gears were measured on the closed power test bed. The results of the speed, torque, transmission error and mechanical efficiency in a given working condition were obtained. The distribution of the contact regions was obtained by coloring method. The values of mechanical efficiency obtained by experiment are in keeping with the same trend compared with the results from theoretical calculation.