With the delivery of the first thrust bearing for the Robbins Company's tunnelling machine, the Components Division of the Liebherr Group has now made its appearance on the American tunnelling market. The two-row roller bearing with a diameter of 2,500 mm ensures reliable shield rotation of the propulsion machine over the entire tunnel length. The thrust bearing’s reliability is essential in tunnel construction, since replacing it during tunnelling is very complex and costly. The shield of the tunnel boring machine (TBM) has a diameter of three and a half metres and is meant for supply tunnels, but TBMs can reach a size of 14 metres or more for road, railway, and other tunnels. In addition to the one-piece bronze cages, a special feature of the Liebherr roller bearing is the pre-tensioned holding track. It is pre-tensioned using disc springs, so that the rolling elements of the holding track are in contact with the track in all load situations.
In this application too, Liebherr bearings meet high demands in terms of reliability and service life. In spite of fierce local competition, Liebherr succeeded in being selected as the component supplier. Robbins tunnelling machines are exposed to extreme loads and environmental conditions, such as high temperatures and coarse dirt and dust. “When selecting the bearing manufacturer, Liebherr impressed us with its application engineering expertise as well as its high production standards. That is why we like to work with companies who know from personal experience how these conditions affect the technology and components”, explains Dale Spurio, Global Sourcing Manager for The Robbins Company. Thus, Liebherr was awarded the project.
The Robbins Company has been operating internationally in the field of tunnel boring machines for more than 60 years. After commissioning, the tunnel boring machine will be used by an end customer in China.