Importance

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Abstract

A pneumatic brake booster (10) comprises a control valve (22) for controlling a pneumatic pressure difference, a force input element (24) for actuating the control valve (22), a force output element (38) for transmitting the braking force, a reaction disk (34) made of elastomeric material disposed between the force output element (38) and the force input element (24), and a device, which is disposed between the reaction disk (34) and the force input element (24) and acts upon the reaction disk (34), for varying the force transmission ratio between force input element (24) and force output element (38) in dependence upon the force exerted on the force input element (24). For a less expensive design and greater ease of assembly, the device for varying the force transmission ratio is designed as a preassembly unit in the form of a cartridge (30), which after preassembly is insertable into the control valve (22). The cartridge (30) comprises a plunger (42), of which the end facing the reaction disk (34) is connected to a piston (50), a hollow-cylindrical operating piston (52), which surrounds the piston (50) and is displaceable relative to the latter, a stop (60), which is provided on the plunger (42) and defines an initial position, in which the areas of operating piston (52) and piston (50) facing the reaction disk (34) form a common, flush area, and a spring (48), which is supported against the plunger (42) and which biases the operating piston (52) towards the stop (60).

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First Claim