Freudenberg-NOK Sealing Technologies Introduces Low-Friction Dual-Material Seal for Improved Performance in Dry Running Piston

  Freudenberg-NOK Sealing Technologies Introduces Low-Friction Dual-Material
       Seal for Improved Performance in Dry Running Piston Applications

Developed to provide more consistent performance without altering existing

PR Newswire

PLYMOUTH, Mich., May 9, 2013

PLYMOUTH, Mich., May 9, 2013 /PRNewswire/ --Freudenberg-NOK Sealing
Technologies Simrithas developed a new friction optimized seal that fits in
existing standard sealing grooves. Designed to provide more consistent
performance, the combined elastomer / polytetrafluoroethylene (PTFE) system
offers low break away force, improved durability and temperature resistance
for dry running piston type systems such as air brakes or pneumatics.

According to Freudenberg-NOK, an elastomeric seal needs a continuous oil film
to operate at the same friction levels as a PTFE seal and the commonly used
elastomeric energized PTFE seal is difficult to install. In dry running
conditions, the coefficient of friction for rubber is normally around 1.5 to
2, but can be optimized to a minimum of approximately 0.4 to 0.5 with special
designs and materials, whereas for PTFE it is primarily around 0.1 to 0.2 in
its natural state. Samples of Freudenberg-NOK's dual material seal were tested
side-by-side verses the traditional elastomeric D-ring type seal at various
pressures for dynamic and break away force. The results showed a reduction of
overall friction by two times at zero pressure and three times at 10 bar.

"Our customers look to us to create application-specific improvements that
they can easily implement into current design specifications without a major
change to the production process," said Joel Johnson, global vice president of
technology, Freudenberg-NOK Simrit. "Our new dual-material seal provides the
needed performance enhancements to the fluid power and heavy duty truck
markets without the cost of redesign."

The dual-material seal provides very low initial breakaway torque and
friction, as well as high-temperature consistency and a comparable
installation to that of an o-ring, including direction independence,
"twist-safe" performance and gap extrusion resistance. The new design also
offers increased design freedom, as a variance of geometries and diameters are
available to minimize friction differences even when utilizing all production
tolerances. The PTFE layer is bonded to an elastomer, which then can be bonded
to a solid carrier if required. Freudenberg-NOK found that such a concept
could be used to minimized friction and improve the overall comfort at gear
changing in automatic transmission. Additionally, the seal eliminates
stick-slip, the effects of rubber aging, the influence of temperature and the
effect of hysteresis.

About Freudenberg-NOK Sealing Technologies

Freudenberg-NOK Sealing Technologies is the Americas joint venture between
Freudenberg and Co. in Germany and NOK Corp. in Japan. Freudenberg-NOK is a
leading producer – through its Automotive, Merkel, Process Seals and Simrit
sales channels – of advanced sealing technologies for a variety of markets
including: aerospace; agriculture; appliance; automotive; construction;
diesel engine; energy; food and beverage; heavy industry; and pharmaceutical.
Founded in 1989 under the legal name Freudenberg-NOK General Partnership,
Freudenberg-NOK is headquartered in Plymouth, Mich. and operates more than 20
facilities across the Americas. For additional information, please visit

SOURCE Freudenberg-NOK Sealing Technologies

Contact: Cheryl Eberwein, Director, Media Relations, Office: +1 734 354 7373,
Cell: +1 248 767 1068, E-Mail:; Lisa Gentile, Public
Relations, Office: +1 734 354 5439, E-Mail:
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