Patent ID: 6073733
Filing Date: 2000-06-13
Classification: F16D

Abstract:
A disc brake apparatus for use in a hydraulic brake system having a master cylinder for generating a hydraulic signal which is communicated through a hydraulic line and proportional to an actuation force applied to inner and outer pads for resisting rotation of a brake rotor of the type found on motor vehicles, said disc brake apparatus comprising:an inboard cylinder member including a bore;an inboard piston slidably housed within said bore of said inboard cylinder member, said piston having a first end adapted to force the inner pad onto the brake rotor in response to the hydraulic signal applied to a second end of said in board piston;an inboard seal disposed between said inboard piston and said bore of said inboard cylinder member;an outboard cylinder member having a bore and a first shoulder therein;said bore of said outboard cylinder member having first and second bore portions axially aligned and having said first shoulder therebetween, said second bore portion being adjacent to the outer pad and having a smaller diameter than said first bore portion;a bridge member spanning the brake rotor and the inner and outer pads and interconnecting said inboard and outboard cylinder members;an outboard piston slidably housed within said bore of said outboard cylinder member and having a first end adapted to force the outer pad toward said brake rotor in response to the hydraulic signal applied to a second end of said outboard piston;a second shoulder extending radially outward from an outer surface of said outboard piston for engagement with said first shoulder of said outboard cylinder member to retain said outboard piston in an applied position; andan outboard seal disposed within said bore of said outboard cylinder member, said seal being sufficiently compressed by said outboard piston in said applied position so as to return said outboard piston to a resting position upon release of said hydraulic signal;wherein said outboard piston further comprises first and second piston portions axially aligned with said second shoulder disposed therebetween, said first piston portion being in a sealed relationship within said first bore portion and said second piston portion being in a sealed relationship with said second bore portion.