HYDRAULICALLY-ACTIVATED PARKING BRAKE WITH A MECHANICAL LOCKING DEVICE

摘要

The invention relates to a parking brake operated by means of a fluid, typically a hydraulic fluid, for application of the parking brake and means for mechanical locking and/or clamping of the brake in the activated state. Said parking brake is a disc parking brake comprising at least one piston, operated by a fluid under pressure, typically a brake fluid, arranged to slide in a blind drilling machined in a brake caliper, said drilling forming a cylinder. A fluid pressure source pushes the piston in the direction of the disc and thus securely applies the pads to the same with a force sufficient to guarantee the immobilisation of the vehicle. According to the invention, a possible release due to the cooling of the brake is preferably taken account of, whereby an actuator displaces a fixing wedge (15) for the piston, preferably in a direction non-parallel to the axis of the above, preventing the retraction thereof relative to the disc to a distance which would risk the release of the parking brake. The actuator preferably displaces the wedge (15) in a rectilinear movement along an orthogonal axis or essentially orthogonal to the axis of the piston. However, an oblique translation movement, a rotation or a movement parallel to the axis of the piston is not excluded from the invention. In a preferred embodiment the wedge is moved in translation by means of the pressure in the hydraulic chambers (29, 29') arranged a the axial ends thereof or by the pressure in a central part of the wedge (15), hermetically sealed with relation to the hydraulic chambers (29, 29').