Disc brake caliper

A disc brake caliper comprising:

• a caliper body arranged to straddle a brake disc having a rotation axis defining an axial direction (A-A) and opposite friction surfaces;
• a cylinder having a cylindrical wall and a bottom wall transverse to the cylindrical wall;
• a piston accommodated within the cylinder and configured to slide in the axial direction (A-A);
• a rotating member being rotatably accommodated about a rotation housing formed in the bottom wall of the cylinder, wherein the cylinder defines a first annular housing extending transversely to the axial direction (A-A) and leading into the rotation housing, wherein a first seal is disposed in the first annular housing, the first seal comprising at least an O-ring and a backup ring, the backup ring being interposed between the rotating member and the O-ring, wherein the backup ring comprises at least one annular groove in the interface where the backup ring abuts the rotating member.

A disc brake caliper comprising a caliper body arranged straddling a brake disc having a rotation axis defining an axial direction (A-A) and opposite friction surfaces, said disc brake caliper further comprising pads accommodated in the caliper body so as to slide in the axial direction (A-A) with respect to the brake disc to act respectively on the opposite friction surfaces,

• the disc brake caliper further comprising:
• a cylinder, forming a cylindrical wall and a bottom wall transverse to the cylindrical wall;
• a piston, forming a side wall and a thrust wall transverse to the side wall and opposite to the bottom wall of the cylinder,
• wherein the bottom wall forms an inner surface facing towards the piston and an outer surface facing opposite to the piston,
• wherein the piston is accommodated within the cylinder, and the side wall of the piston is configured to slide within the cylindrical wall of the cylinder,
• wherein the piston is further configured to be biased by a pressurized brake fluid injectable within the cylinder, to affect at least one of the pads against one of the friction surfaces, along a thrust direction substantially parallel to the axial direction (A-A), said disc brake caliper further comprising a parking-braking system that comprises a rotating member, the rotating member being rotatably accommodated about a rotation housing formed in the bottom wall of the cylinder so that the rotating member is rotatable about a rotation axis substantially parallel to the axial direction (A-A), wherein the cylinder defines a first annular housing and a second annular housing made in the bottom wall,
• the first and second annular housings extending into the bottom wall in a direction transverse to the axial direction (A-A) and leading into the rotation housing,
• the second annular housing being distinct from the first annular housing and being positioned in a direction opposite to the inner surface of the bottom wall with respect to the first annular housing,
• wherein the bottom wall of the cylinder forms, at a second annular housing, at least one backing step that determines a concave polygon-shaped profile of a second annular housing in the section parallel to the axial direction (A-A),
• wherein the first annular housing accommodates a first seal, and the second annular housing accommodates a second seal, and
• wherein the first and second seals are configured to act between the rotating member and the bottom wall of the cylinder to be fluid-tight.