A brake boost assist system for use with a master cylinder of a motor vehicle braking system, includes an inductive sensing system. The inductive sensing system has sensing devices carried on an input member and an output member, where the input and output members are coupled to respective ones of an input rod and an output rod of the brake boost assist system. Movement of the input and output members relative to one another, and relative to a fixed element of the inductive sensing system positioned within the brake boost assist system, enables an accurate estimation of the distance of a pedal gap which separates faces of the input and output rods. The accurate estimation of the pedal gap distance enables a more accurate determination to be made of the braking force required for any given pedal stroke input by an operator of the vehicle during a braking action.

A pneumatic brake booster for a hydraulic motor-vehicle brake system, including a booster housing, having a front and a rear housing shell, and at least one connecting pin, which is arranged in the booster housing such that the at least one connecting pin extends axially parallel to the center axis and which supports the booster housing from the inside by two supporting formations and which protrudes through the booster housing from the inside to the outside on at least one side by an end segment. In order to ensure simple intermediate handling of the brake booster before and during the assembly of the brake system and to improve the durability and corrosion resistance, the housing shells are arranged in such a way that the housing shells are each connected to the connecting pin such that the housing shells are secured against being axially moved apart from each other.

A pneumatic brake booster for a hydraulic motor-vehicle brake system, including a booster housing, having a front and a rear housing shell, and at least one connecting pin, which is arranged in the booster housing such that the at least one connecting pin extends axially parallel to the center axis and which supports the booster housing from the inside by two supporting formations and which protrudes through the booster housing from the inside to the outside on at least one side by an end segment. In order to ensure simple intermediate handling of the brake booster before and during the assembly of the brake system and to improve the durability and corrosion resistance, the housing shells are arranged in such a way that the housing shells are each connected to the connecting pin such that the housing shells are secured against being axially moved apart from each other.

An input rod is operated by a brake pedal to introduce the air into a variable-pressure chamber through a control valve to propel a power piston, thereby advancing a primary piston to generate a brake fluid pressure in a master cylinder. A part of the reaction force from the fluid pressure is transmitted to the input rod through a reaction member. The primary piston is provided with an idle stroke in which no fluid pressure is generated, and the reaction force to be transmitted to a plunger is limited by a reaction force adjusting spring. In the region of the idle stroke, a fluid pressure is supplied to a wheel cylinder through a fluid pressure control unit to perform regenerative cooperative control, and a reaction force from a reaction spring is applied to the input rod.

An input rod is operated by a brake pedal to introduce the air into a variable-pressure chamber through a control valve to propel a power piston, thereby advancing a primary piston to generate a brake fluid pressure in a master cylinder. A part of the reaction force from the fluid pressure is transmitted to the input rod through a reaction member. The primary piston is provided with an idle stroke in which no fluid pressure is generated, and the reaction force to be transmitted to a plunger is limited by a reaction force adjusting spring. In the region of the idle stroke, a fluid pressure is supplied to a wheel cylinder through a fluid pressure control unit to perform regenerative cooperative control, and a reaction force from a reaction spring is applied to the input rod.