Aerodynamic Noise Reduction of Brake Disc for High-Speed Trains

Wayside noise reduction arises as a major issue when increasing the Shinkansen’s operating speed. We have been working on reduction of noise from the lower part of train cars, a major source of Shinkansen noise. First, using the experimental train “FASTECH360”, we identified the noise source from around wheels. We confirmed that noise from around the wheels was aerodynamic noise generated from air through the ventilation route of brake discs. Thus, we developed a low-noise brake disc for new Shinkansen Trains “Series E5.” Next, we used test equipment to investigate the mechanism of noise generation of the rotating wheel with a low-noise disc attached to further improve the low-noise disc. As a result, we found that: (1) Air through the ventilation route generated noise over 700 Hz and this noise consists mostly of noise generated by rotating wheels with low-noise brake discs; (2) Circumference gap generated noise around 500 Hz; (3) Bolt holes generated noise around 2500 Hz.