Brake rotors, or brake disks, are arranged to be mounted to and rotate with a wheel hub of a vehicle as part of the vehicle's braking system. Brake rotors, for example, generally include two oppositely-facing annular friction surfaces which, during operation of the brakes, are engaged by two blocks of friction material (e.g., brake pads) that are moved towards one another into contact with the two friction surfaces so that frictional forces occur and slow the rotation of the rotor, and hence the wheel of the vehicle. These frictional forces, however, may also cause the rotors, brake pads, and caliper (which houses the brake pads and fits over the rotor) to become very hot, which may lead to reduced braking efficiency. High temperatures, for example, may cause problems such as brake fade (temporary loss of braking due to the reduction of the friction coefficient between the friction material and the brake rotor), brake fluid vaporization, component wear (including thermal deformation of the brake rotors), and thermal judder (vibrations that the driver can feel and hear).
In order to reduce temperature/heat accumulation in the brake rotors that is caused by the frictional forces, rotors may include, for example, vents that are cast into the edge of the rotor to allow the heat that has built up on the metal of the rotor to escape. Conventional ventilated rotors may include, for example, friction members (which carry the oppositely-facing annular friction surfaces) that are arranged in a spaced-apart parallel relationship. The friction members are joined by vanes or fins therebetween, which form cooling ducts extending radially and outwardly of the rotor. The cooling ducts are arranged so that, as the rotor is rotated, air passes through the ducts and acts to cool the friction members.
Although such ventilated rotor designs provide some heat dissipation from the rotor (to help cool the friction members), the heat dissipation provided is limited by the amount of fin surface area exposed to the air flow passing through the ducts. The air flow through each duct is, for example, only exposed to one side of each fin, thereby limiting the amount of convective heat dissipation provided by each fin.
It may, therefore, be advantageous to provide a ventilated brake rotor with an enlarged heat dissipation area to dissipate more heat energy from the rotor. It may also be advantageous to provide a ventilated brake rotor design that reduces the mass of the rotor.