空气制动机是各国铁路沿用的一种制动装置,四十年代后期,随着有机化学工业水平的提高,合成橡胶密封件逐渐普遍采用,由此各国铁路对旧的制动装置不断进行革新。新的制动装置基本上都采用了新材料、新工艺,减少了研磨件,从而提高灵敏度,延长检修期,到目前绝大部分已处于推广运用阶段。五十年代欧洲各国装用的制动机均采用三种压力机构,全橡胶密封,有较高的制动波速,客货通用,无紧急加速器,适用于较短列车运用。五十年代后期美国西屋公司在AB阀基础上设计了AC阀,除保 Air brake is a kind of braking device used by all countries. In the late 1940s, with the improvement of the organic chemical industry, the synthetic rubber seals were gradually adopted, and the national railroad constantly renewed the old brake devices . The new brake devices are basically used a new material, new technology, reducing the grinding parts, thereby increasing the sensitivity and extend the overhaul period, the vast majority have been in the promotion and application stage. Fifties European countries equipped with a brake are used in three pressure agencies, all rubber seal, a higher brake wave speed, passenger and cargo common, no emergency accelerator, suitable for shorter train use. In the late fifties, Westinghouse designed the AC valve on the basis of the AB valve, except Paul