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Noise, Vibration and Harshness problems in rotors and drums show up in different forms in automotive brakes. The NVH problems may reside either in foundation brakes, apply systems, anti-lock systems or having nothing to do with brake systems but are related to other automotive components such as suspensions, wheel bearings, tire and wheel, drive axle or body structure. The NVH issue is a major warranty cost issue that the car manufacturers and suppliers have to face. Hayes Lemmerz has patented a new rotor design where lowering noise and vibration were the main design criteria. We have used a design concept unique to the brake industry but commonly used to dampen noise. The rotor introduces a sound deadening layer under the brake cheeks. The brake cheeks are attached to brake ribs or fins by a safe and reliable joining method, with the noise damping layer molded on the rear of brake cheeks. We have achieved noise reduction of 50% compared to current production design rotors.

Hayes Lemmerz has made an enormous leap in technology by creating a new “4 in 1” disc rotor that solves brake industry noise, dimension accuracy, thermal diffusivity and “hot spot” rotor problems. By closely adhering to a disciplined system of concurrent planning, product development and production feasibility studies (which included material development and CAE design and dynamometer and vehicle tests), Hayes has solved the brake industry's top four warranty concerns. Development of several propriety manufacturing methods, production system/equipment and quality assurance procedures followed to bring this product from the Development Laboratory to the Production Plants. Hayes' new brake rotor is designed with damped iron composition, 72 curve fin rotor geometry and is then processed using Hayes' patented ULTRA-Q process. The 72 curve fin rotor design, developed through previous Hayes efforts (Ref-1,2,3,4) creates a 100 degrees F cooler running rotor.

Hayes Lemmerz, in a previous paper (Ref-1), has introduced an HQ (Hayes Quiet) rotor design where the noise level was reduced by 50%. In this paper, various methods of joining the brake plates to the fins are investigated. The effect of welding is to create a metal joining path which connects the bell shape of the rotor and consequently, the noise level increases. Glue between the brake plates and fins acts as an excellent noise damping layer, but welding through such a layer introduces porosity. The successful design used in the HQ Rotor is when brake plates and long fins are glued together and in place of short fins flat head screws that are used to hold the brake plates against the fin's surfaces. The result of this joint is a Q-Factor number of 211. Damped iron cast joints exhibits a Q-Factor of 500. Glued joints with screws show a Q-Factor of 211 and this kind of joint does not raise the Q-Factor compared to just glued joints.