| 摘要 |
PROBLEM TO BE SOLVED: To enable brake output to become strengthened in non-operating of a brake, so as to achieve simplification of a structure and reduction of cost, by providing a clearance amount changing means for changing the clearance between an input member of a plunger member and an engaging part. SOLUTION: A brake pedal is operated, a plunger 20 is moved leftward through an input rod 11, a vacuum valve member 26g is brought in contact with a valve seat 10a of a power piston 10, and then engagement of an air valve member 26f with the plunger 20 is eliminated. Therefore, the power piston 10 is moved leftward by the pressure difference between constant pressure chambers 6, 8 and pressure changing chambers 7, 9. At this time, a reaction disc 15 is deformed, so as to fill the clearance Z to a second input member 14, and braking force is increased until the reaction disc 15 is brought in contact with the second input member 14. When brake operation is not performed like in the wheel slip control, an electromagnetic solenoid 17 is driven, and the amount of the clearance Z is increased, therefore, large brake output is generated. |
