Abstract: According to the present invention, the master cylinder of a motor vehicle actuating unit has a bipartite flange, and one part of the flange is provided as a mounting plate which is guided on a spherical bead shaped on the master cylinder. The mounting plate clamps the master cylinder in relation to the wall of a brake force booster. This ensures that the master cylinder may escape or may be deflected in a rearward direction in the case of a crash, without transmitting an excessively large amount of force to the wall of the brake force booster.

Abstract: Retaining element fixed within the piston opening which avoid any inadvertant extraction of the piston rod from the piston.The design provides a safe and easy to assemble means for fastening the piston rod within the piston which is capable of absorbing considerable tractive forces of said piston rod through said piston.The retaining member is preferably made of plastic material which resides between the piston rod and the piston.

Abstract: The present invention relates to a piston with a central valve, in particular for hydraulic boosters, the valve case (6) which is composed of a supporting insert (8) radially embraced by a valve seat (7). It is disadvantageous in some valve cases that sometimes the positive coupling between the two elements in axial direction is not sufficient. The present invention provides a remedy to this problem by using undercuts behind which the valve seat engages the supporting insert in both directions. In an advantageous improvement, the valve insert is of symmetrical design, and a sealing projection is shaped at the valve seat. The guidance of the valve tappet (19) is performed within the piston (1).

Abstract: The present inventive relates to a master cylinder (1 ) with elastomeric central valves (20) which can be opened in opposition to a relatively high pressure in the pressure chambers (8 and 9) without damage. The sealing face (29) of the valve member (26) is in the form of a hollow cylinder protruding slightly from the broad head portion (24) of the valve pin (21). The valve member sealing face does not, as has been conventional practice, extend radially inwardly past the head portion (24) in the direction of the central bore (13) to avoid being drawn into the bore (13).

Abstract: A process for the manufacture of a master cylinder for hydraulic brake units of automotive vehicles. The starting material is a pasty material which is between solid and liquid. In the course of the casting procedure, thin material wall thicknesses are created in the regions of intended openings of the master cylinder, such as the breather bore (14) and the intake bore (5). The floating membrane (12) which forms during the casting process is removed by mechanical machining to open the duct which functions as the intake bore. The breather bore (14) which functions as the compensation bore is formed by a stamping operation.

Abstract: A process for the precise adjustment of the lost travel of a piston in a master cylinder. Master cylinders typically include a number of components in spatial series arrangement, with all components having individual tolerances. The individual tolerances regarding the lost travel of the piston or pistons, can combine additively in the master cylinder. The resulting lost travel, hence, is relatively large and varies with individual master cylinders. The process provides that the lost travel of the piston or pistons in the master cylinder can be precisely adjusted and, hence, can be kept very low. The position of the piston or pistons is measured in the condition in which they just seal the associated equilibrium ports. Subsequently, the position of the pistons is calculated in consideration of the desired lost travels and, by adjustment of the force planes acting on the desired point, the resting position of the piston and pistons, respectively, is fixed to the desired distance.

Abstract: The die-casting mold and the die-cast brake master cylinder housing comprise an axial master cylinder piston bore and a compensating bore, whose latter axis extends parallel to the axis of the master cylinder piston bore. The compensating bore has one end terminating in a compensating reservoir port oriented transversely relative to the housing's longitudinal axis and its other end terminating in a sealing chamber that is formed by an extension of the master cylinder piston bore. To render the casting process for manufacturing a die-cast brake master cylinder housing simpler, the mold comprises a core for the compensating bore whose longitudinal cross-sections containing the longitudinal axis are of conical construction, with the narrowest point being adjacent to the compensating reservoir port and whose cross-sections extending vertically to the longitudinal axis are of substantially reniform construction, while the concave sides of the cross-sections are close to the master cylinder piston bore.