Caliper brake apparatus

A caliper brake apparatus configured to sandwich a disc rotatable together with a vehicle wheel, and to apply a frictional force to the disc, the caliper brake apparatus comprising:

• a caliper main body supported on a vehicle body;
• a brake block that is configured to advance and retreat relative to the caliper main body and to slide against the disc so as to apply the frictional force to the disc;
• a pressing mechanism that is configured to press the brake block against the disc using a pressure of a working fluid;
• and
• an adjuster that supports the brake block on the caliper main body,
• wherein the adjuster includes:
• an anchor pin that is configured to advance and retreat relative to the caliper main body and supports the brake block on the caliper main body;
• a brake block bearing that supports the anchor pin to enable the anchor pin to advance and retreat;
• a return spring that biases the brake block in a direction heading away from the disc;
• and
• a back pressure chamber which is defined on a back surface of the anchor pin, and into which the working fluid is led,
• wherein the pressing mechanism includes:
• a piston that is configured to press the brake block against the disc;
• a cylinder having an interior in which the piston is slidable;
• and
• a diaphragm that defines a fluid chamber in the cylinder and is deformable by variation in the pressure of the working fluid in the fluid chamber so as to apply a pressing force on the brake block to press the brake block against the disc, and
• wherein the caliper brake apparatus further comprises:
• a quill provided between the cylinder and the brake block bearing to connect the fluid chamber to the back pressure chamber.