| 摘要 |
PROBLEM TO BE SOLVED: To increase hysteresis without any increase of hardness of a reaction disc. SOLUTION: A circular recess part 3B is formed on an end face 3A' of a circular projection 3A in a valve body 3. A circumferential face 3a constituting the circular recess part 3B is formed into a taper whose diameter is expanded toward the front side. When a brake booster is operated after a brake pedal is pressed, compression in the axial direction is carried out, and the inside of the circular recess part 3B is filled with a reaction disc 24. When the brake pedal is released from the operating condition, resistance is given for restoration of the reaction disc 24 to the original form by means of the circumferential face 3b of the circular recess part 3B. |
