工程设计；工程勘察；铁路、城市轨道交通用金属及化学材料、车辆用设备、配件及材料、工务工程用设备、配件及材料、维修轨道板、焊接技术、焊接设备、焊接材料的技术开发、技术服务、技术转让、技术咨询、技术推广；销售计算机、软件及辅助设备、化工产品（不含危险化学品）、润滑油、机械设备、建筑材料、装饰材料；施工总承包；专业承包；劳务分包；租赁机械设备（不含汽车租赁）；软件开发；技术检测服务；建设工程项目管理（市场主体依法自主选择经营项目，开展经营活动；工程设计、工程勘察以及依法须经批准的项目，经相关部门批准后依批准的内容开展经营活动；不得从事国家和本市产业政策禁止和限制类项目的经营活动。）
Taking the axle box bearing of a high-speed EMU as an example, this paper established the vehicle dynamic model of axle box bearing under the condition of outer ring damage, and obtained the axle box acceleration under different speed levels. Aiming at the interference caused by wheel rail vibration,the diagnostic method of envelope demodulation after band-pass filtering was used. The effectiveness of the monitoring method was verified by the axle box acceleration at different speed levels. After using different band-pass filter frequencies, the first-order frequency amplitude of envelope spectrum was analyzed after envelope demodulation. The results showed that the first-order amplitude of 6～8 kHz was higher than the other two frequency bands by two orders of magnitude, indicating that the component of this frequency band was more obvious; The first-order amplitude obtained after envelope demodulation of the two frequency bands of 11. 5～13. 5 kHz and 19～21 kHz was the same order of magnitude, of which the frequency band of 19～21 kHz was larger.
