United Kingdom supplier GKN Driveline says it has developed two lighter low-friction joints that reduce noise and vibration, save fuel and let vehicles turn in a tighter circle.
The company says its new constant-velocity, or CV, joint design not only will make cars and SUVs smoother and quieter but also will permit improved steering angles. That means those vehicles will be able to turn more tightly and that designers can increase wheelbase to provide better packaging and comfort.
Constant-velocity joints are the flexible couplings at the end of the driveshaft in rear-drive vehicles and between the transmission and axle in front-drive cars.
GKN calls the joints the first major improvements in constant-velocity joint technology since the device was patented in the 1930s and used on the radical front-wheel-drive Cord in 1936.
One new joint, called Countertrack, is designed to fit on driveshafts for rear-wheel-drive vehicles. The other, called Crosstrack, works on the shafts used in front-wheel and all-wheel-drive vehicles.
Both use unique ball bearings and ball-bearing tracks to reduce friction.
The company says the Crosstrack will arrive in the United States in 2007 but did not disclose on what model.
Countertrack will debut in 2008 on two European and two Japanese models.
1 million units
"By 2010, new-technology CV joint production will be 1 million units a year," says Al Deane, GKN's global engineering director.
"Future developments cannot overcome the generic limits" of the old design, Deane told Automotive News Europe, which, like Automotive News, is owned by Crain Communications Inc. "Vehicles are getting smaller but also more powerful. We're hitting the limits on things like heat and friction."
The new designs improve fuel efficiency by both reducing friction and being lighter. But GKN believes its primary selling point is sharper turning.
"The main push from our customers is in SUVs," Deane said. "They want to get a better turning circle and easier parking."
GKN's Countertrack coupling can run at angles up to 52 degrees. Present joints are limited to 50 degrees, the company says.
"The extra two degrees makes a surprising difference," says Rob Rickell, GKN global engineering director for sideshafts.
"Existing vehicles could turn one meter tighter or designers could go for a longer wheelbase to improve passenger space without losing any maneuverability."