Brake pad for vehicle disc brake
A brake pad ( 10 ) includes a backing plate ( 12 ) of plastic material, a friction lining ( 14 ) overmolded on the backing plate ( 12 ) and a metal reinforcement plate ( 16 ) embedded in the backing plate ( 12 ). The backing plate ( 12 ) has a solid peripheral structure ( 18 ) and an inner structure ( 20 ) made as a grid-like reticular structure having a plurality of cavities ( 22 ) evenly distributed on its surface and filled at least partially by the material of the friction lining ( 14 ). At least part of the cavities ( 22 ) are made as through cavities, whereby the friction lining ( 14 ) forms columns ( 24 ) which extend into the through cavities ( 22 ) and improve the adhesion between the friction lining ( 14 ) and the backing plate ( 12 ). The area of the through cavities ( 22 ) amounts at least to 4.5% of the area of the face of the friction lining ( 14 ) opposite to the one in contact with the backing plate ( 12 ).
1. Brake pad comprising a backing plate of plastic material, a friction lining overmoulded on the backing plate, and a metal reinforcement plate embedded in the backing plate; the backing plate comprising a solid peripheral structure and an inner structure having a plurality of cavities filled at least partially by material of the friction lining; wherein at least part of the cavities are made as orifices extending through the inner structure of the backing plate; wherein undercuts are formed by the plastic material in the orifices of the backing plate; and wherein the orifices occupy an area amounting at least to 4.5% of the area of a face of the friction lining opposite to a face in contact with the backing plate.
2. Brake pad according to claim 1 , wherein the inner structure of the backing plate projects with respect to the peripheral structure, in a direction perpendicular to a plane of the backing plate, on a side of the backing plate facing towards the friction lining.
3. Brake pad according to claim 1 , wherein the cavities are evenly distributed on a surface of the inner structure of the backing plate.
4. Brake pad according to claim 3 , wherein the inner structure of the backing plate is made as a grid-like reticular structure comprising a first set of parallel and equally-spaced ribs and a second set of parallel and equally-spaced ribs, which extend at an angle to the first set of ribs, defining the cavities as having a rhombic shape.
5. Brake pad according to claim 1 , wherein the cavities occupy an area amounting to at least 40% of the area of a face of the friction lining opposite to a face in contact with the backing plate.
6. Brake pad according to claim 1 , wherein the backing plate is made of thermoplastic polyetherketone.
7. Brake pad according to claim 1 , wherein the reinforcement plate has through holes aligned with corresponding ones of the cavities of the backing plate and having an identical shape to a shape of said cavities, the material of the friction lining filling at least partially said through holes.
8. Brake pad according to claim 1 , further comprising a wear indicator or a temperature probe incorporated in the backing plate.
9. Brake pad according to claim 8 , wherein the backing plate further has a first blind cavity in which the wear indicator is accommodated or a second blind cavity in which the temperature probe is accommodated.