Abstract: The invention is directed to a rotor having a vented hat section. A plurality of spaced apart vents are defined in the rotor hat wall. The vents are defined by a first aperture in the radially outer hat wall surface, a second aperture in the radially inner hat wall surface and a vent wall extending therebetween. The vent wall includes an upper surface and a lower surface which extend from the from the first aperture to the second aperture. The upper surface and lower surfaces form an angle A with respect to the outer surface of the hat wall which partially determines the quantity of air moved through the vents when the rotor turns. The vent wall also preferably includes a pair of approximately parallel side surfaces between the upper and lower surfaces which extend through the hat wall. The angle B of the vent wall side surfaces with respect to the radius of the rotor partially determines the quantity of air pushed or pumped through the vents when the rotor turns.

Abstract: The noise created by a vehicle rotor is reduced by adjusting the natural or resonant frequency at which the rotor tends to vibrate. The resonant frequency is moved away from the frequencies of excitation of such sources as the brake pads and vehicle drive train components. The resonant frequency of the rotor is adjusted by manipulating the geometry and mass of the rotor by adjusting the number, size, shape, spacing and location of cooling vents formed in the hat section of the rotor. The resulting rotor exhibits improved vibrational control.

Abstract: The invention is directed to a rotor having a vented hat section and a method of forming the same. Such a rotor includes a hat section having a central mounting face and a cylindrical shoulder or hat wall extending axially from the mounting face to an annular peripheral section having friction surfaces disposed on opposite sides. A plurality of spaced apart vents are defined in the wall of the hat section. The vented rotor is formed by first casting a rotor to the desired configuration including at least the hat section. The initial casting is formed in such a manner that one or more depressions are provided in the radially inner surface of the wall of the hat section. These depressions do not extend through the wall of the hat section. Then, material is removed in one or more machining steps from the radially outer surface of the wall of the hat section proximate the depressions.

Abstract: The invention is directed to a method of forming a vented rotor for caliper disc brakes and the like. Such a vented rotor includes an outer friction portion having one or more ring sections with opposed friction surfaces adapted to interface with associated friction members. The vented rotor is formed by first casting a rotor to the desired configuration including at least the ring section. This initial casting is formed in such a manner that one or more depressions are provided a surface of the ring section. Then, material is removed in one or more machining steps from portions of the friction surface opposite the friction surface having the depressions, to the point that the depressions extend completely through the ring section to form the vents.