| MATERIALS
Application Xtra |
PAI bushings
• withstand impact, wear
• withstand high temp
When the Houston-based Risi Competizione Ferrari race team became frustrated with having to change the suspension bushings on their three Ferrari 360GTs after every race, shortly before the Daytona 24 Hours, they searched for a material that would solve the problem. In this race particularly, “the car’s handling becomes very sloppy due to bushing wear that occurs during the race” says Steve Quance, president of Drake Plastics Ltd. During the race, the 8 upper and 8 lower suspension bushings in the car will be subjected to much strain without the benefit of lubrication or maintenance. Worn bushings allow lateral movement of suspension components, resulting in increased wear on the tires, reduced stability in cornering and braking, and poor handling in general.  “The press-fit suspension bushings must withstand severe impact loading without fracturing, wearing or creeping,” says Quance. The Risi team upgraded to suspension bushings made from Torlon 4435 polyamide-imide (PAI). Torlon resins are produced by Solvay Advanced Polymers LLC. Drake manufactures the bushings for the team using their extruded Torlon PAI seamless tube process.
“Since Torlon 4435 was used, the bushings have exhibited zero wear in four races, including Sebring, Daytona and LeMans,” says Richard Taylor of the Risi team. “Torlon PAI solved the problem.” Torlon features high wear resistance under severe service conditions without external lubrication and at high temperatures — up to 260°C. Additionally, the PAI offers metal-like thermal expansion properties, eliminating fit and clearance problems. The material’s high strength and stiffness allows it to replace metals in many applications. Other applications include rotating and sliding components for bearings, seal rings, thrust washers, wear pads, fasteners and thermal insulators.
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