In service brake systems of passenger cars and lightweight commercial vehicles, the braking forces are generally transmitted hydraulically. The advantages of this form of force transfer lie in the incompressibility of the transferred medium, the low transmission losses, and last but not least, the higher flexibility in transfer lines when compared to mechanical elements.
A hydraulic brake system generally consists of the following design elements:
Pedals (acquating device)
Brake booster (optional)
Master cylinder (transmission system)
Wheel brake cylinder (transmission system)
According to legal regulations, service brake systems are to be operated by the driver's foot over pedals. The pedals have to mechanically transfer the foot force while simultaneously amplifying it. The principal structure of a brake pedal is shown in the figure.
The foot force Ff is transformed over the pedal multiplication iP into the actual control force Fop acting on the transmission system: