Negative pressure-type booster device

A negative pressure-type booster device comprising

• a valve mechanism including:
• a movable partition member dividing the inside of a housing into a negative-pressure chamber and a variable-pressure chamber;
• a valve body reciprocally mounted in the housing and coupled to the movable partition member in the housing;
• an air valve which is disposed in an axial hole formed in the valve body, can be reciprocated along an axial direction of the axial hole with respect to the valve body, and moves integrally with an input member;
• a negative-pressure valve communicating/blocking the negative-pressure chamber with/from the variable-pressure chamber depending on reciprocation of the air valve with respect to the valve body;
• and
• an atmospheric-pressure valve communicating/blocking the variable-pressure chamber with/from atmospheric air, wherein
• the valve mechanism has a valve part in which a negative-pressure valve seat disposed on the valve body, an atmospheric-pressure valve seat disposed on the air valve, a negative-pressure valve section constituting the negative-pressure valve together with the negative-pressure valve seat, and an atmospheric-pressure valve section constituting the atmospheric-pressure valve together with the atmospheric-pressure valve seat are disposed, and
• includes a tilting part which is formed at least any one of the valve body and the valve part and relatively tilts the atmospheric-pressure valve section with respect to a first plane formed when the negative-pressure valve section and the negative-pressure valve seat are bought into contact with each other to set the negative-pressure valve in a blocking state.