Abstract: To improve the carrying capacity and stability of transmission system, the transmission system of the newly developed 400 km/h high-speed train in China adopts double-helical transmission gear for the first time. The installation errors and unique symmetry errors of double-helical gear will lead to deviation load on the gear surfaces at both ends, reducing the service life of gears. This paper established a train-track coupling dynamic model considering the gear transmission system to obtain the dynamic contact loads of double-helical gear in wheel-rail excitation environment, and analyzed the gear deviation load behavior under different forms of machining and installation errors. The results show that, under the axial constraint of small gear, when symmetry errors of 10 μm and 50 μm exist in the double-helical gear, the average errors of gear surfaces contact load reach 17.2% and 145.3%, respectively. Under the axial floating of small gear, when symmetry error of 100 μm exists in the double-helical gear, the average error of gear surfaces contact load is 1.0%, which can effectively improve the deviation load behavior of double-helical gear. Slight parallelism installation errors can cause significant deviation load on individual gear surfaces, however, the contact load distribution of left and right gear surfaces remains generally consistent. The partial deviation load behavior of the double-helical transmission gear of high-speed train can be suppressed by modifying the gear surface. The research results provide guidance for determining the reference value of machining error and installation forms of double-helical transmission gear in China’s new generation of high-speed train.

Key words: high-speed train, double-helical transmission gear, symmetry error, parallelism error, gear deviation load