| 摘要 |
PURPOSE: A vacuum pump used for a brake system is provided to prevent sudden loss of braking force while traveling, and to improve braking stability by preventing vacuum pressure of a brake booster from flowing backward to the housing in wrong operation of the vacuum pump. CONSTITUTION: A vacuum pump is composed of a housing(11) having an air passage(11a) communicated with a brake booster, a rotor(13) composed of vane installation grooves(13a) in the outer periphery and eccentrically installed in the housing, and a vane(14) installed in the vane installation groove. The vane is formed of a steel ball bearing to prevent breakage in rotating the rotor at high speed, and a check valve(21) is installed in the air passage and opened in supplying vacuum pressure from the housing to the brake booster. The vacuum area between the housing and the rotor is decided according to the radius of the ball bearing contacted to the bore of the housing and protruded from the vane installation groove.
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