| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative pressure type assistor which does not inhibit operation response and reduces room air flow sound.SOLUTION: A negative pressure type assistor is configured so that in a shaft hole 22a of a valve body 22, a valve mechanism V comprising a negative pressure valve for communicating and locking between a negative pressure chamber R1 and a pressure variable chamber R2 according to forward and backward movement of a plunger 32 to the valve body 22, and an air valve for communicating and blocking between the pressure variable chamber R2 and room air, is incorporated. The valve mechanism V comprises a cylindrical valve body 41 having: a negative pressure valve seat 22d on the valve body 22; a room air valve body 32d on the plunger 32; a negative pressure valve part 41b1 forming a negative pressure valve with the negative pressure valve seat; and a room air valve seat 41b2 forming a room air valve with the room air valve body, on a movable part 41b, and is incorporated in the shaft hole. On an outer peripheral edge of the room air valve body 32d, a ring-shaped projection 32d2 for generating a vortex flow separating from a taper face of the room air valve body 32d and winding back toward room air immediately after passing a gap generated by separation from the room air valve body 41b2, is provided.SELECTED DRAWING: Figure 1 |
