SKF Grouphas rolled out a line of energy-efficient bearings for driveline applicationsthat could cut friction by up to 30 percent and carbon dioxide emissions by upto 13 gm per mile.

The new bearings offer reduced friction on anapplication-by-application basis for cars, trucks, agricultural equipment,construction machinery and even wind turbines.

"The real target is to minimize the friction by applyinglower loads to the rolling elements," says Thomas Wolf, senior engineer forpowertrain and steering at SKF's Automotive Div. in Germany. "Whether it's a car or apiece of construction equipment or a truck, the idea is always to reduce thefriction."

SKF accomplishes that by applying its Vehicle EnvironmentalPerformance Simulator (VEP) software program to individual design applications.The simulator uses a variety of inputs, including engine torque, engine speed,vehicle mass, air drag and rolling resistance of tires to help determine theloads on the bearings. By knowing the loads, the resulting stresses, stiffnessmatrix and the desired bearing life, the program can optimize the internalgeometry of the bearing, including the number and diameter of rolling elements,as well as the contact angle.

SKF's portfolio of low-friction bearings includes taperedroller bearings, angular contact ball bearings for drivelines, double-row ballbearings for pinion units and hybrid pinion units with double-row bearings withballs and tapered rollers.

By doing the VEP analysis on its portfolio of bearings, SKFclaims it can reduce friction by as much as 30 percent. Wolf says the bearingsare designed for use in virtually any type of mobile application.

"Even wind turbines can use the energy-efficient taperedroller bearings," he says. "But drivelines are still the application that ismost promising for energy reduction."