## 1 Introduction  
Tooth contact analysis (TCA) technology is widely applied for assessing meshing quality duet to the increasing demand for vibration, strength, and mechanical efficiency of gear in various industrial fields such as aviation, automotive, and civil engineering [1; 2]. There are some main evaluation items to reflect the tooth contact performances. For instance, the transmission error has a significant impact on gear vibration and noise, and the qualified contact pattern can avoid edge contact and premature failure [3; 4; 5]. Using a meshing simulation, the transmission errors and contact pattern of the gear pair can be determined.  
Currently, the new optimization method based on the loaded tooth contact analysis (LTCA) for improving strength and contact performance of bevel gears has been a great concern to scholars worldwide. [PERSON] analyzed the influences of machine settings and misalignments on tooth contact pressure and loaded transmission error, and then presented a method to improve gear meshing performance by reducing the loaded transmission error and the maximum tooth contact pressure of hypoid gears [6; 7; 8; 9; 10]. [PERSON] et al. studied the ease-off optimizing method for loaded transmission error and contact surface of bevel gears, which reduced the risk of vibration and noise [11; 12; 13]. [PERSON] et al. [14; 15] developed a novel formulation for LTCA using the ease-off topography. The study defined the surface of action and roll angle surface to simplify the task of locating the instantaneous contact curves. [PERSON] et al. proposed an ease-off flank modification method to solve the problem of the design and fabrication of high contact ratio spiral bevel gears with a seventh-order transmission error [16]. [PERSON] et al. studied a new method of tooth surface topography modification for improving the meshing performance and correct contact area of spiral bevel gears [17].  
Furthermore, a lot of research efforts have already gone into the analysis and optimization of individual gear pairs by experimental testing. [PERSON] et al. discussed the theoretical analysis and experimental research on load transmission error and actual coincidence of spiral bevel gears [18]. [PERSON] et al. investigated the tooth contact pattern and transmission errors of large-sized spiral bevel gears, and these analyzed results were compared with experimental ones [19]. [PERSON] et al. investigated the contact characteristics of hypoid gears under quasi-static condition, and proposed a method for the global optimization of the tooth contact pattern and transmission error of spiral bevel and hypoid gears [20; 21]. [PERSON] et al. discussed a new method for gear tooth contact analysis, which concentrates on solving two considerable disadvantages of the generalized algorithm, which were verified with the gear-rolling test [22]. [PERSON] et al. studied the influence of different grinding parameters on the surface topography and compared the simulation results with experiment results [23].  
It can be seen that the research of loaded contact analysis and experimental testing of spiral bevel gear has not been sufficient so far. There are few comprehensive studies on its high loading comprehensive contact performance. In this work, an accurate finite element model of spiral bevel gear transmission system was established, which was based on the generating principle of spiral bevel gear and meshing theory. This model considered the influence of gear and shaft deformation, installation position, and bearing load, and the contact characteristics under quasi-static loading and high loading condition were analyzed through this model. In addition, a contact performance test bench of spiral bevel gear pair was developed in this paper, and the bending stress, contact pattern and transmission error test results were obtained for validating FEM results and the reliability of proposed model.