| 摘要 |
PURPOSE:To reduce the variation of the jumping level greatly by giving a rounding to the square section of the reaction disc identical to that given to the square section of a large diameter hole on the power piston in the reaction mechanism used to reduce the brake pedal depressing force of the automobile. CONSTITUTION:The part of the power piston 12 that houses the control valve machanism 20, the output member 39 and the reaction disc 44 is molded with a resin material. A rounding is given to the square section 44a of the reaction disc 44 identical to that given to the square section of a large diameter hole provided at the center 12a of the power piston 12. This rounding reduces the friction force between the square sections 44a and 42a to facilitate the inward movement of the peripheral section of the reaction disc 44 in the radial direction when the reaction disc 44 extends into the small diameter hole 43 on the power piston 12. Thus, the change in the jumping level can be lessened against the variation in the clearance, thereby increasing the allowable dimensions of the parts such as air valve 22. |
