Patent ID: 8225910
Filing Date: 2012-07-24
Classification: F16D

Abstract:
1. In a brake caliper comprising a caliper body to be arranged astride a brake disk having an axis of rotation and opposed friction surfaces, pads for acting on said friction surfaces, and at least one piston seat containing a piston for moving at least one of said pads against said friction surfaces of the brake disc when said piston is driven towards said pad by application of hydraulic pressure, the improvement comprising a device for controlling roll-back of the piston when said pressure is released, said device comprising: a bush arranged externally of and coaxially with said piston, a scraper element seated in a first seat formed in a surface of the piston seat, said first seat substantially preventing deformation of the scraper element in a piston movement direction during piston operation, said scraper element bearing against said bush with a pressure determining a frictional resistance force to piston movement, elastic means disposed between the piston and the bush and elastically acting on the bush and, when stressed by the piston movement, elastically yielding up to an abutment position, said elastic means having a predetermined elastic constant that determines an elastic return force of the piston into its seat, said elastic return force being substantially less than the frictional resistance force exerted by said scraper element, whereby, during movement of the piston, said scraper element slides relative to the piston only after the elastic means have reached said abutment position, preventing further deformation as the piston slides relative to the scraper element, and a seal disposed in a second seat formed in said piston and bearing against a side surface of the piston seat.