真空助力 meaning in English

vacuum servo

Study on the backing velocity of the vacuum booster
汽车真空助力器回程速度的研究
Research of relation between max points of booster force and transmission ratio
关于真空助力器助力比与最大助力点关系的研究
Shao xing county fine machinery manufacture co . , ltd . （ the former shao xing county automobile brake factory ） professionally manufacture construction machinery , air boost , vacuum booster and spring break actuator for forklift truck , automobile and tractor , air pressure or hydraulic pressure , single or double break , master or subsection cylinder , footplate , tracked assembly , and so on
绍兴县精致机械制造有限公司(原绍兴县汽车制动器厂)专业生产工程机械、叉车、汽车、拖拉机空气加力器、真空助力器、弹簧制动室、离合助力器、汽压、液压、单、双管路制动、离合总泵、分泵和踏板支架总成等。