Orkot® bearings wear well at low velocities
In tests, Orkot® bearings from Trelleborg Sealing Solutions prove to have exceptionally low wear.
Trelleborg Sealing Solutions Orkot® TXMM bearing material is proven to be one of the best in direct electric motor propulsion systems on ships. The motors operate at low shaft velocities and, subject to boundary lubrication, bearings used must demonstrate exceptional wear resistance.
Proven in extensive test program
An extensive test program was conducted to prove Orkot® TXMM bearing material performance at low velocities. Bearings were tested to extremes velocities down to five meters/ 16 feet per minute at pressures up to six bar/ 87 psi and water flows down to two liters/ four pints per minute. The seawater contained Silica flour at 250 parts per million and the 200 mm/ eight inch bearing operated on an LG4 Bronze sleeve for 2,000 hours. The resulting overall wear of the bearing was just 0.027 mm/ 0.001 inch per 1,000 hours and shaft wear was minimal with an improved shaft finish. The tests were repeated successfully with Inconel and Nickel Chrome Boron coated shafts.
Image shows Orkot® bearings
“Orkot® is a unique material. Resistant to sea water, it is proven in numerous marine applications,” says Brian Tarrant, Engineering Sales Manager for Orkot® bearings. “The bearings perform exceptionally in demanding low velocity situations. This translates into benefits for our customers. Orkot® bearings have almost twice the bearing life of alternative products.”
Low friction needed to minimize wear
High shaft velocities in traditionally designed propeller shafts generate a water film which reduces friction on the bearing. Conserving energy, the latest electric drives rotate propeller shafts at low speeds and bearings are subject to boundary lubrication with no water film separating the shaft from the bearing. The bearing material is in contact with the shaft and to ensure acceptable bearing life materials must exhibit low friction properties to minimize wear on the shaft and its liner.
Orkot® Marine Bearings are manufactured from unique synthetic composite incorporating solid lubricants. Virtually no swelling in sea water and very low thermal coefficient of expansion provide dimensional stability in arctic and tropical seas. The bearings do not corrode or promote corrosion of the housing and tolerate both edge loading and misalignment.
For more information on Orkot® Marine Bearings