has rolled out a line of energy-efficient bearings for driveline applications
that could cut friction by up to 30 percent and carbon dioxide emissions by up
to 13 gm per mile.
The new bearings offer reduced friction on an
application-by-application basis for cars, trucks, agricultural equipment,
construction machinery and even wind turbines.
"The real target is to minimize the friction by applying
lower loads to the rolling elements," says Thomas Wolf, senior engineer for
powertrain and steering at SKF's Automotive Div. in Germany. "Whether it's a car or a
piece of construction equipment or a truck, the idea is always to reduce the
SKF accomplishes that by applying its Vehicle Environmental
Performance 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 the
loads on the bearings. By knowing the loads, the resulting stresses, stiffness
matrix and the desired bearing life, the program can optimize the internal
geometry 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 tapered
roller bearings, angular contact ball bearings for drivelines, double-row ball
bearings for pinion units and hybrid pinion units with double-row bearings with
balls and tapered rollers.
By doing the VEP analysis on its portfolio of bearings, SKF
claims it can reduce friction by as much as 30 percent. Wolf says the bearings
are designed for use in virtually any type of mobile application.
"Even wind turbines can use the energy-efficient tapered
roller bearings," he says. "But drivelines are still the application that is
most promising for energy reduction."