Patent ID: 6749044
Filing Date: 2004-06-15
Classification: F16D

Abstract:
A disk brake cylinder having a bore for retaining a piston (5) that is axially moved toward a disk, said piston being connected to a parking brake mechanism for effecting a parking brake application, said parking brake mechanism consisting of:an input member (11) that bears against an axial stop of the cylinder for preventing said shaft from moving in the opposite direction to the disk, said input member (11) being rotated to initiate a parking brake application; and a ball-ramp mechanism, comprising at least a first groove (15) located on a face (11â€²) of said input member (11) and at least a second groove (15â€²) located on a face (13â€²) of a moving member (13), said first groove (15) and said second groove (15â€²) face each other and retaining a corresponding plurality of balls (14) such that rotation of said input shaft causes axial translation in said moving member (13) and pushes the piston (5) toward the disk, said grooves (15,15â€²) each are characterized by an escapement zones (16,16â€²) with a flat bottom (26) that transitions into convex surfaces such that in a position of rest said ball (14) has a point of contact with the convex surfaces near the bottom of the groove (15,15â€²) but never touches the bottom (26) of said groove and as a result initially the ball (14) rolls on the convex surfaces to provide non-linear axially movement of the moving member (13) toward the disk when the input member (11) rotates with respect to the moving plate (13) to rapidly take up the play in the parking brake mechanism.