Brake calipers, which are known in the art, force brake pads towards a brake disc to effect braking of the disc. The brake pads comprise a brake pad backplate, typically stamped from sheet steel, onto which is fixed friction material. The friction material is forced into engagement with the brake disc to effect the braking and progressively wears out through the life of the brake pad. Once the brake pads have worn out, they are removed (with the brake disc and brake caliper in situ) by withdrawing the pads in a radially outward direction with respect to the brake disc. Various retaining features, such as pad springs and pad retainers, need to be removed before the worn brake pads can be removed.
Additionally, the brake caliper will include a housing on one side of the brake disc in which one or more pistons is mounted. A bridge is fixed to the housing (or is integral therewith) and straddles the brake disc to support a further brake pad on the opposite side of the brake disc. The housing and bridge together are known as a brake caliper frame.
The brake caliper frame is slidably mounted on a brake carrier, which in turn is non-rotatably mounted on suspension components adjacent to the brake disc.
During servicing of the caliper, the old worn brake pads are removed from the caliper in a radially outward direction. Clearly, the pads must be prevented from escaping from the caliper when the vehicle is in use. One known way of retaining the pads is to provide a pad retaining strap and bolt (as shown in FIG. 2).
UK patent application GB2303891, for example, shows a brake piston capable of applying a force to a brake pad to apply a brake. However, in this prior art structure the piston is a loosely fitted in a recess of the backplate of the brake pad. The piston is not attached to the brake pad. As such, this design will require additional features, such as a strap and/or bolt (not shown), to retain the pad in the caliper.
An object of the present invention is to provide an improved form of brake caliper that does not require complex pad retention structures.