The vacuum booster master cylinder assembly with brake is a very mature part of the automobile, which is generally composed of a vacuum booster, a hydraulic brake master cylinder, a vacuum check valve, and a brake fluid reservoir.
Tightness is a very important parameter of vacuum booster,
The standard requires related parts
It can be said that airtightness is the most important performance of the vacuum booster with the brake master cylinder. The airtightness requirements of related parts are as follows: The vacuum booster is divided into working state and non-working state (70%~80% below the maximum boost point, 130% above the maximum boost point), the test vacuum degree is -66.7±1.3kPa
The hydraulic brake master cylinder is divided into vacuum tightness (test vacuum degree -98kPa±2kPa), pneumatic tightness, and hydraulic tightness (130% of the highest working hydraulic pressure)
Liquid storage tank tightness (test absolute pressure 250±50Pa, there is not much air left in the tank, in line with the actual vacuum filling state)
The vacuum check valve is divided into vacuum tightness, high-temperature vacuum tightness, low-temperature vacuum tightness