Tandem master cylinder for a hydraulic dual-circuit brake system of a

Abstract

In a tandem master cylinder, the primary and secondary outlet-pressure spaces of which are respectively limited in the axial direction by the push-rod or primary piston and a secondary piston designed as a floating piston or by the latter and an end wall fixed relative to the housing. A restoring spring urging the secondary piston into its basic position is arranged in a central cavity located in the secondary piston which is limited by a blind bore of the latter. The restoring spring is supported on the piston side on the inner face of the bottom of a pot-shaped supporting projection facing toward the primary piston and belonging to the secondary piston and, on the housing side, on a radial stop pin passing through a longitudinal slot of an intermediate part of the secondary piston extending between the two piston flanges which form the respective pressure-tight displaceable limitation of the secondary outlet-pressure space on the one hand and of the primary outlet-pressure space on the other hand. Because of this arrangement of the restoring spring urging the secondary piston into its basic position, that part of the cylinder housing which limits the secondary outlet-pressure space fixedly relative to the housing can be reduced by an amount corresponding approximately to the compressed block length of a restoring spring.