Editor’s Note: N.K. Chinnusamy, president of Excel Gear Inc., Roscoe, Ill.,
which manufactures gears for utility-scale wind turbines, responds.
Work Large
Gears for utility-scale wind
turbine applications are very
large in diameter—up to 70
inches—and have face widths
up to 56 in.
Obviously, the equipment
we must use to manufacture components as large as these must also be
very large and heavy-duty. Our gear
grinding, shaping, and hobbing machines are the largest available.
Special workholding and fixturing
must be able to bear the heavy weight
of the large gears and reduce the vibration and movement of the gear blank
during hobbing and roughing. We must
carefully and uniformly torque the
clamping fasteners during these operations to prevent workpiece movement
and gear blank distortion during the
roughing operation.
The gear blank must have accurate
mounting and indicating surfaces to help
control the pitch line runout to critical
features (bearing journals, splines, and
so forth) and to minimize lead error.
Lead error is the deviation of the actual
advance of the gear tooth profile from
the set value. This can interfere with
good contact in the gear assembly—
a real problem atop a 400-foot wind
turbine! Crowning is one technique we
use to overcome this effect.
What are the top 5 challenges
you face when making gears and
Achieve Exacting
Material
Composition
gearboxes for wind turbines?
In addition, the gears
require very exacting
material composition
and heat-treat processing of the carburized steel. The gear
must be designed and manufactured
