SKF’s new ceramic roller bearings, featured
at IMTS 2004—booth 4696, guarantee uniform machine tool
spindle preloads
BETHLEHEM, Pa. June 7, 2004 — SKF Machine
Tool Precision Technologies, a unit of SKF USA Inc.’s
new single row silicon nitride cylindrical equipped roller bearings
provide, in operation, more uniform preload. These hybrid cylindrical
roller bearings, ideal in high-speed machining center and milling
spindles, offer higher speeds, a more compact design, higher
rigidity and have fewer components than standard ceramic ball
bearings. Their SKF bearing designation is KTNHA/HC5-SP.
The problems of shaft thermal elongation
are eliminated as the roller bearings allow for changes in the
shaft length. Since these silicon nitride cylindrical rollers
are lower in density than standard steel rollers, centrifugal
forces are lower, resulting in reduced friction. These silicon
nitride ceramic roller equipped bearings can achieve speeds
up to 2 million Ndm, which is nearly 50 percent faster than
conventional all steel roller bearings. In addition, the width
is 50 percent narrower and twice as rigid than standard ceramic
ball bearings.
Since the patented polymer cages are made
of lightweight glass fiber reinforced PolyEther Ether Ketone
(PEEK), the cage to outer ring contact has excellent wear resistance,
very low friction and good stability at high speeds. A tapered
bore inner ring allows for the best preload/clearance adjustment
possible. The covered sizes range from 40 to 120 mm bore.
SKF offers an extensive range of bearings
designed for machine tool spindle applications that offer minimal
runout, greater stiffness, high reliability and cooler high-speed
temperatures.
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