The invention relates, generally, to vehicle wheel assemblies used in vehicles such as trucks, buses and trailers, and more particularly, to a composite brake drum and a method of manufacturing the same.
The prior art vehicles include various brake systems for slowing or stopping a vehicle, such as medium and heavy-duty trucks, trailers and buses. The brake system may include a disc brake assembly or a drum brake assembly. The disc brake assemblies include a rotor, which rotates with the wheel and tire, and a caliper having brake pads. The brake pads straddle the rotor and are actuated by hydraulics or air to close upon the rotor and impart friction force to slow or stop the rotation of the rotor. Drum brake assembly includes a drum, which rotates with the wheel and tire, and brake shoes located within the drum. The brake shoes each have a brake pad which faces the interior annular wall of the drum and are hydraulically or air actuated to engage the drum annular wall to impart friction force to slow or stop the rotation of the brake drum.
Prior art brake drums include full cast drums of one material. The prior art drums also include composite drums. Composite drums include a drum which may be initially formed from a steel sheet via one of several different manufacturing methods, including spinning, flow forming and press fit. The brake drum lining may be centrifugally cast using various materials, such as high carbon steel, alloy steel, and grey iron structure.
U.S. Pat. No. 1,876,354 issued to Sinclair and discloses a composite brake drum. The brake drum is pressed or drawn sheet metal cup-shaped drum. The lining is formed of material, such as cast iron, high carbon-steel, alloy steel or the like. U.S. Pat. No. 2,080,895 issued to Nelson and discloses a method of making a brake drum and drum seal. The brake ring portion is preferably formed from sheet metal and is provided with a cast metal liner. U.S. Pat. No. 5,138,757 issued to Ballet al and discloses a process for manufacturing a vehicle brake drum. The drum is formed from sheet steel stock and rolled. Grey iron structure is then centrifugally cast within the drum to form a composite brake ring. U.S. Pat. No. 6,572,712 issued to Powell et al. and discloses a compacted graphite iron brake drum.
It is an object of the present invention to provide a brake drum which has an increased drum life, particularly as to the wear life.
It is an object of the present invention to provide a brake drum which has an increased drum life, particularly as to the structural life.
It is a further object of the present invention to provide a brake drum which will accommodate shorter vehicle stopping distances, by providing a more aggressive brake lining with a harder drum wear surface.
The present invention therefore provides in one embodiment, a vehicle brake drum comprising a brake drum shell, and a brake drum liner, the brake drum liner formed of compacted graphite iron.
The present invention further provides in another embodiment, a method of manufacturing a composite brake drum, the method comprising the steps of forming a brake drum shell, and forming a brake liner of compacted graphite iron.
Referring particularly to
The brake drum 10 shown in
This application claims the benefit of U.S. Provisional Application No. 60/705,250, filed Aug. 3, 2005.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US2006/030172 | 8/3/2006 | WO | 00 | 2/4/2008 |
Number | Date | Country | |
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60705250 | Aug 2005 | US |