Alfred Treves Gmbh

Holger V Hayn

Hans-Dieter Reinartz

Helmut Steffes

A method is suggested for assembling a tandem master cylinder and a vacuum brake booster of a hydraulic brake system for automotive vehicles. Air is injected via the pressure connection (19) of the pressure chamber (18) associated with the push-rod piston (2). Simultaneously, the push-rod piston (2) is moved in the direction pointing away from the brake pedal. The pressure increase in pressure chamber (18) is measured during the movement of the push-rod piston and, thus, during the movement of the central valve (6) accommodated in the push-rod piston. As soon as the closure member (5) of the central valve is seated on the valve seat (4), thus the central valve being closed, the air pressure will increase in the chamber (18). In the curve of the 'pressure-against-central-valve-travel' diagram, which curve indicates the pressure increase, a trigger point is established which determines a measured distance on the abscissa of the diagram. Said measured distance is the standard for the number and/or dimensioning of spacing washers (8) to be arranged between the pressure element (9) and the push-rod piston in order to achieve a reduction of the lost travel of the central valve. By means of this invention, an elegant method in conformity with the demands of automation is achieved for assembling a tandem master cylinder and a vacuum brake booster and for simultaneous reduction of the lost travel of the central valve.

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Bad Vilbel, Germany

Holger V Hayn