NTN - Precision Rolling Bearings
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Technical Data<br />
Life under high temperature<br />
The test results obtained from thrust-type test pieces<br />
at 200˚C are graphically plotted in Fig. 8.2.<br />
Improved wear resistance<br />
Test results with a Sawin type friction and wear test<br />
machine are illustrated in Fig. 8.3.<br />
Test conditions<br />
Test piece<br />
Ball<br />
Max. contact stress<br />
Loading frequency<br />
Oil temperature<br />
Lubricant<br />
Schematic of test rig<br />
4729t7 flat plate<br />
6.351/4"Ceramic ball<br />
5.5 GPa<br />
3,000 cycles/min<br />
200˚C<br />
Ether-based oil<br />
Test conditions<br />
Speed<br />
Peripheral speed<br />
Test duration<br />
Max. contact stress<br />
Lubricant<br />
Rotating test piece<br />
Fixed test piece<br />
4775 min -1<br />
10 m/s<br />
10 min<br />
2.0 GPa<br />
VG2<br />
Material being tested<br />
Si3N4<br />
Schematic of test rig<br />
Rotating<br />
test piece<br />
Fixed test piece<br />
Special<br />
material<br />
2310 -6 mm 3<br />
Ceramic ball<br />
SUJ2 14410 -6 mm 3<br />
Cumulative probability of failure (%)<br />
99<br />
80<br />
50<br />
20<br />
10<br />
5<br />
SUJ2<br />
Special material<br />
No flaking<br />
1<br />
10 5 10 6 10 7 10 8<br />
SUJ2<br />
Special material<br />
Life (loading cycles)<br />
L10 (10 5 cycles)<br />
9.1<br />
No flaking<br />
Test piece (flat plate)<br />
Life ratio<br />
1<br />
30<br />
Amount of wear<br />
The wear resistance of the special material is<br />
6 times better than that with SUJ2.<br />
Fig. 8.3 Test results with Sawin type friction and wear<br />
test machine<br />
Improved anti-seizure property<br />
Test results with a two roller testing machine are<br />
illustrated in Fig. 8.4.<br />
Test conditions<br />
Driving side speed<br />
Driven side speed<br />
Sliding velocity<br />
Max. contact stress<br />
Lubricant<br />
Driving roller<br />
Driven roller<br />
200 min -1<br />
120 min -1<br />
10.1 m/s<br />
2.9 GPa<br />
VG2<br />
Material being tested<br />
Material being tested<br />
Schematic of test rig<br />
Driven roller<br />
Driving roller<br />
The rolling fatigue life of the special material<br />
at a high temperature of 200˚C is more than<br />
30 times as long as that of SUJ2.<br />
Special<br />
material<br />
3000 min or longer<br />
Fig. 8.2 High temperature life test results with thrusttype<br />
test pieces<br />
SUJ2<br />
200min<br />
Duration<br />
The anti-seizure property of the special material is<br />
more than 15 times better than as that with SUJ2.<br />
Fig. 8.4 Test results with a two roller testing machine<br />
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