Slewing Bearings in Tunnel Boring Machines – Keeping the World Turning
Slewing bearings are impressive due to their sheer size and their innovative engineering. They are used in machines that have to withstand enormous forces. Wind turbines, cranes, excavators, or tunnel boring machines, need the machine elements to turn impressive visions into reality.
Because large-diameter slewing bearings are used wherever motion and drive come together. In tunnel boring machines, slewing bearings are the connective part of the cutter head. As main shield bearings, they ensure that it rotates. Thereby, the cutter head can fight its way through rock and withstands the loads acting on it.
Since tunnel boring machines are designed specifically for the geological conditions (such as the hardness of the rock), bore diameter and type of tunnel, the slewing bearings used must also be designed and manufactured individually for each machine. A challenge for the engineers, as each bearing design, must be based on individual service life requirements and specifications. thyssenkrupp rothe erde specializes in these requirements and manufactures all the main components of its slewing bearings in-house - from the raw material to the finished product.
To date, thyssenkrupp rothe erde has produced more than 2000 main shield bearings. The high-quality standard of the products is of enormous importance, as the dismounting and repair of a defective bearing is expensive and involves massive effort or is not an option at all. For major projects such as the Gotthard Base Tunnel, the reliability of the bearings and smooth operation of the machines is crucial. In this project, four rothe erde® slewing bearings were used.
Slewing bearings can be manufactured with a diameter of up to 9.6 m as a single piece. Segmented slewing bearings are produced with a diameter of up to 18 m. However, size is not the only variable characteristic of the bearings. Their specific design and material also differ according to customer requirements. Additionally, various bearings are used in tunnel boring machines, for example, main shield bearings and erector bearings. These include single-row ball bearings, three-row roller bearings, and cross roller bearings. Each finished slewing bearing is therefore unique and specifically adapted to its requirements.
Moving people & innovations
Tunnels make a decisive contribution to infrastructure, energy supply, and people's mobility both in isolated and hard-to-reach areas and urban centers. Large-diameter slewing bearings ensure progress everywhere in the world under the most adverse conditions; they are always on the move - so that the world can be too.
If you want to learn more about thyssenkrupp rothe erde®'s innovations, feel free to have a look at their website.