Plastic bearings replace metal and ceramic bearings in ring motor

Profile

• What was needed: Plain bearings for the ring motor
• Requirements: The motor and bearing points are underwater all the time. The bearings must therefore function permanently when subjected to high salt content and possible contamination. In addition, the lightest possible bearings were required as any additional weight would mean increasing the size of the drive.
• Industry: Ship and boat building
• Success for the customer: The polymer bearings proved to be the best solution for the application: in contrast to metallic solutions, they are corrosion-free and lightweight. And compared to ceramic bearings, they have a higher load limit and are extremely wear-resistant.

In ring motors (torque motors), there is no mechanical connection between the rotor and stator during operation. The magnetic ring (rotor) is only centred by the magnetic field of the stator and held in the magnetic field. A bearing for the magnetic ring is therefore only necessary during the start-up phase of the motor.
However, the demands on the bearing position are particularly high due to the special environmental and operating conditions. The ring motor and bearing points are permanently underwater and are exposed to high salt content, corrosion and possible contamination. It was also important to find bearings that were as light as possible, as any additional weight in the water would be expensive due to an increase in the size of the drive.

The designers ultimately decided in favour of using iglidur J plain bearings in the ring motors, which were able to solve the problems permanently. The polymer bearings are suitable in and on underwater vehicles and boats due to their corrosion resistance, low moisture absorption and low weight compared to metallic solutions.

Unlike ceramic bearings, they also have a high load limit and are extremely wear-resistant. While initial tests with impacts led to problems with the ceramic bearings, the special bearing made from high-performance polymers remained dimensionally stable in the long term - another important factor for dynamic applications.