Patent ID: 7258207
Filing Date: 2007-08-21
Classification: F16D

Abstract:
1. An automatic shoe clearance adjusting apparatus for a drum brake of motor vehicles comprising: (a) a strut regulating a returning position of a pair of brake shoes and a driving member installed on the strut, said strut including (b) the driving member, said driving member including said automatic shoe clearance adjusting apparatus has an automatic shoe clearance adjusting mechanism, for expanding the strut to adjust a shoe-to-drum clearance by unthreading the nut member out from the bolt member when the fitting member and the nut member are separated while the pawl element of the driving member makes a one-way-rotation of the nut member, due to the resilient force of the arcuate leaf spring element of the driving member, when strokes of the brake shoes exceed a predetermined value while releasing an axial force acting on the strut, wherein when a temperature of the arcuate leaf spring element of the driving member exceeds a predetermined degree, the temperature weakens the resilient force of the arcuate leaf spring element due to thermal deflection in the direction to reduce curvature of the arcuate leaf spring while keeping ratchet engagement of the pawl element against the ratchet wheel, thereby suspending an automatic shoe clearance adjusting operation.