Patent ID: 6905179

Claim:
A braking system for providing a braking force through a wheel brake in response to movement of a brake pedal, the braking system including an anti-lock braking system (ABS) for controlling the braking force during an ABS event, the braking system comprising: a reservoir containing brake fluid; a master cylinder including a piston having a lip seal for closing off a compensation port linking the reservoir to the master cylinder; a brake line including a brake conduit and a return conduit in fluid communication with the wheel brake; a pump connected to the return conduit for pumping fluid from the wheel brake to the master cylinder during an ABS event; an accumulator positioned between the wheel brake and the pump, the accumulator having cylinder defining a bore and a piston fitted within the bore, the cylinder defining an inlet and an outlet fluidically connecting the bore to the return conduit, the cylinder having an end wall and a side wall defining the bore, the end wall being stepped to define an inner portion and an outer portion of the end wall, the outer portion being axially spaced from the inner portion, the inlet being located at the inner portion of the end wall and the outlet being located at the outer portion of the end wall, the pump connected to the accumulator only by way of the outlet of the accumulator; and the outlet being axially spaced from the inlet and positioned to be sealed closed by the piston when the piston is proximate the inlet, the piston being translatable axially to open the outlet and fluidically connect the pump to the wheel brake, the accumulator storing a reserved volume of brake fluid that is not delivered to the pump via the outlet to thereby reduce the volume of fluid delivered to the master cylinder by the pump and prevent damage to the lip seal.