| 摘要 |
A movable diaphragm of a negative pressure type booster device includes an annular rubber diaphragm and an annular metal plate. The diaphragm is airtightly pinched by the housing at an annular outer peripheral bead portion formed at an outer peripheral edge of the diaphragm, and airtightly secured to an outer peripheral portion of a valve body, together with an inner peripheral portion of the plate, at an annular inner peripheral bead portion formed at an inner peripheral edge of the diaphragm. Between the outer peripheral bead portion and the inner peripheral bead portion, there are formed a folded portion having a curved portion toward the front and continuous with the outer peripheral bead portion at an outer peripheral area, and an annular portion continuous with an inner peripheral area of the folded portion and with the inner peripheral bead portion. |
| 主权项 |
1. A negative pressure type booster device configured such that a valve body connected to a movable diaphragm partitioning an interior of a housing into a forward negative pressure chamber and a rear pressure conversion chamber has a shaft hole, a plunger which can be reciprocated in an axial direction with reference to the valve body and moves integrally with an input member and an a valve mechanism including a negative pressure valve performing communication/cutoff between the negative pressure chamber and the pressure conversion chamber depending on reciprocal movement of the plunger with reference to the valve body and an air valve performing communication/cutoff between the pressure conversion chamber and atmospheric air are built in the shaft hole, a reaction member having a rear surface with which a front end portion of the plunger and a front end portion of the valve body can be engaged and an output member having a rear end portion engaged with a front surface of the reaction member and being capable of moving in an axial direction with reference to the valve body are mounted, and the movable diaphragm and the valve body operate with an operation of the input member to operate the output member, wherein
the movable diaphragm includes an annular rubber diaphragm and an annular metal plate disposed in front thereof, the rubber diaphragm is airtightly held at an annular outer peripheral bead portion formed on an outer peripheral edge of the diaphragm in the housing, and is airtightly fixed on an outer peripheral portion of the valve body together with an inner peripheral portion of the metal plate on an annular inner peripheral bead portion formed on an inner peripheral edge of the diaphragm, between the outer peripheral bead portion and the inner peripheral bead portion, a folded portion having a curved portion on the front side and connected to the outer peripheral bead portion at an outer peripheral portion is formed, an annular portion connected to an inner peripheral portion of the folded portion and the inner peripheral bead portion is formed, and the rubber diaphragm is molded in a condition in which a shape of the folded portion is a form in an active state. |
