| 摘要 |
A hydraulic brake booster for use in a brake system having a housing with a power piston located in a first bore and a control valve located in a second bore. An input member is connected to the power piston and linked to the control valve by a lever arrangement. The input member is characterized by a cylindrical body with a shaft attached thereto. A bracket with a radial opening is carried by the shaft and urged toward a head on the shaft by a spring. The lever arrangement is characterized by a first lever with a first end pivotally secured in the housing by a first pin and a second end located in the radial opening of the bracket and a second lever pivotally secured at a fulcrum on the first lever by a second pin extending through the first and second levers. A first input force applied to the cylindrical body is transmitted through the spring into the bracket and communicated through the fulcrum point to bring a first end of the second lever into engagement with the control valve and a second end of the second lever into engagement with the power piston. The first input force as applied to the bracket causes the end of the first lever to pivot about the first pin and transmit an actuation force through the fulcrum into the said second pin to move said first end and activate said control valve to meter pressurized fluid into the working chamber to develop a hydraulic force for effecting a brake application. The lever arrangement ratio defined by a first length between the first pin and the second end on the first lever and a second length between the first pin and the second end of the second lever such that axial movement of the cylindrical body and the power piston is defined by this ratio and as a result a hydraulic force produced by the metered pressurized fluid proportional to a manual input force.
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