| 摘要 |
<p>A hydraulic brake booster includes a spool valve within a housing for communicating fluid pressure into a chamber for urging a piston in a direction actuating a master cylinder, thereby effecting a brake application. The communication between an inlet passage and the chamber is regulated by a land on the spool valve cooperating with a corresponding land on the housing. In order to prevent particles which are carried in the pressurized fluid from wedging in the interface between the land and the corresponding housing land, an additional land is provided on the spool valve. The additional land cooperates with another land on the housing to form a small clearance therebetween so that large particles in the fluid are prevented from wedging in the interface between the sensitive land and the corresponding land on the housing when the valve is in the brake-released position.</p> |
