The vacuum pump is mostly the power source of the hydraulic brake booster of diesel vehicles, which is usually driven by the generator coaxially and rotates in the same direction. The rotor is biased in the casing, and the carbon blades are precisely matched with the rotor chute, which is made close to the inner wall surface of the casing by the spring pressure. The air inlet on the upper part of the housing is connected to the vacuum cylinder, and the backflow of air and lubricating oil is prevented by a check valve. The lower part has an oil outlet leading to the crankcase,

The working process and principle are:
1) suction effect. Since the rotor is offset in the casing, the volume of each blade in the rotor and the inner wall of the casing is a variable. When the volume changes from small to large, negative pressure is generated to inhale, and from large to small, it is compressed and exhausted.

2) When the rotor rotates, the blades move outward due to centrifugal force, forming a certain volume with the pump casing. When the blade crosses the air inlet, the volume gradually expands, which makes the air inlet generate negative pressure, opens the check valve and sucks the air in the vacuum tank.

3) The rotor continues to rotate, when the vane crosses the middle position of the intake port to the exhaust port, the volume begins to shrink, and the air is gradually compressed.

4) When the blade reaches the exhaust port, all the compressed air is squeezed out. This process is repeated, and the negative pressure in the vacuum tank is gradually increased. The degree of vacuum is related to the integrity of the vacuum pump.