Patent ID: 6659236
Filing Date: 2003-12-09
Classification: F16D

Abstract:
In a disc brake having a support member secured to a vehicle, said support member having first and second guides to align a caliper over a rotor associated with a wheel of the vehicle, said caliper having an actuation section connected by a bridge to an arm, said actuation section having a bore therein for retaining a piston to define an actuation chamber, a first friction member connected to said piston and a second friction member connected to said arm, said actuation chamber on being presented pressurized fluid from a source acting on said piston and actuation section to develop a dynamic clamping force for moving said first and second friction members into engagement with said rotor to effect a first brake application, a ball-in-ramp actuator having a first member axially retained in said actuation chamber and connected to a lever and a second member radially retained in said actuation chamber, an adjustment screw mechanism having a first end connected to said second member of said ball-in-ramp actuator and a second end that engages said piston, said first member of said ball-in-ramp actuator receiving an input force from said lever and rotating to correspondingly act through a linkage defined by said ball-in-ramp actuator to axially move said second member and transmit an actuation force through said adjustment screw mechanism into said piston to produce a static clamping force for moving and maintain said first and second friction members in engagement with said rotor to effect a brake application, said caliper, support member and rotor each responding to thermal expansion and thermal contraction with corresponding dimensional changes during a duration of time for said second brake application, said adjustment screw mechanism being characterized by a head having a first member splined to a second member, a first spring located between said first and second members and a shaft that extends from the second member and is connected to said ball-in-ramp actuator by a threaded connection, said threaded connection including first threads located in a bore of a cylindrical member that extends from said ball-in-ramp actuator and second threads being located on said shaft, said first threads and said second threads having a desired lash there between to permit limited independent movement with respect to said ball-in-ramp actuator said clamping force when initially applied to effect said brake application compressing said first spring between said first member and said second member, said first spring during said duration of time for said brake application proportionally expanding as a function of said thermal contraction of said disc brake to compensate for such dimensional changes in said caliper, support member and rotor by sustaining a substantially constant static clamping force on said piston.