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NTN Bearings Develops the Revolutionary
SFJ, Shudderless Freering Tripod Joint
Constant velocity Joints (CVJ's) are used in a variety
of applications including front-wheel-drive (FWD) and
four-wheel-drive (4WD) vehicles. Because they efficiently
deliver torque to the wheels, providing turning flexibility,
they are indispensable for stable and smooth driving.
Here we introduce the new SFJ (Shudderless Freering
Tripod Joint) which has even better performance than
other CVJ's.
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SFJ (Shudderless
Freering Tripod Joint) |
What is the SFJ?
A drive shaft is comprised of a shaft flanked by two
CVJs, generally of different types. Usually a fixed
joint CVJ, for example a ball fixed joint (BJ) or undercut
free joint (UJ) is installed on the wheel side, while
a sliding CVJ called a plunging joint, such as a double
offset joint (DOJ), a tripod joint (TJ), a freering
tripod joint (FTJ) or a cross groove joint (LJ) is used
on the engine side. The SFJ introduced here is an improved
FTJ and it ensures a smoother, more comfortable ride.
The SFJ Mechanism and Future Potential
TJ type CVJ's have low slide resistance and are highly
effective in eliminating vibration during idling for
A/T vehicles. However, resonance between the engine
mount and the CVJ's induced cyclical axial load sometimes
causes shudder when the vehicle starts to move. Consequently,
there was a strong demand from automobile manufacturers
for a CVJ with less induced cyclic axial load.
We began with a standard TJ, developing and mass producing
low vibration joints known as the AC-TJ and the FTJ.
Subsequently, in response to requests from automobile
manufacturers for even lower vibration, we developed
the SFJ. Because we were able to keep costs lower than
those for the FTJ, we have received many inquiries,
not only from Japan but also from automobile manufacturers
in North America, Europe and Korea. Since March 1997,
the SFJ has been used in Fuji Heavy Industry's FWD and
4WD Legacy and in the 4WD Impreza and Forester. Some
of the above, we have been told, were only made possible
by the new SFJ. A dramatic new development, the SFJ
is an outstanding CVJ. (Y. Tanigaki, NTN Corp. Osaka,
Japan).
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