Slewing bearings and drives by Liebherr contribute to the exploration of the universe

Nussbaumen (Switzerland), November 20, 2023 – A new chapter in space research begins with antennas for what will be the largest radio astronomy facility in the Northern Hemisphere. "The ultra-sensitive imaging capabilities of these groundbreaking instruments will give us an unprecedented look into space and help unlock the secrets of the universe," explains Lutz Stenvers, Managing Director of mtex antenna technology GmbH. The new generation antennas, boasting a diameter of 18 metres, will be positioned in a clearly defined pattern throughout North America. The area with a total of 244 antennas will cover approximately 1,000 kilometres. The special arrangement of the antennas will ensure optimal data reception from the cosmos.

"With cutting-edge technology, precision engineering and a tireless commitment to scientific discovery, rockets the project to the forefront of astrophysical research," continues Lutz Stenvers. "And Liebherr's components take over an important role in this."

Precision at a blink of an eye: the seamless synergy of three elements

Crucial for the operation of an ngVLA are the components installed in it - a slewing bearing, two gear ring segments and azimuth drives. The slewing bearing is used for azimuth adjustment of the antenna to enable its precise positioning. Thereby, this roller bearing has a diameter of 3.3 metres. Its weight of 4,128 kilogrammes provides for more stability; its axial runout of 0.1 mm and radial runout of 0.05 mm plays a decisive role when it comes to precision. The slewing bearing is designed to be free of backlash, making it ideal for adjusting the azimuth of the antenna.

As a complementary feature to the slewing bearing, the gear ring segment is of great importance for the elevation adjustment of the antenna, meeting the high demands on the gear quality. The two gear ring segments, each positioned on the sides of the horizontal antenna rotation axis, ensure its exact elevation adjustment.

In addition, the interaction of the azimuth drives with the slewing bearing enables a high degree of precision, with which the satellite systems rotate around the tower axis. The key is a low torsional backlash and increased stiffness of the planetary gears. These optimisations make the adjustment mechanism of the entire system operate with maximum accuracy, targeting precise positioning in the long run.

The elevation adjustment, which is responsible for the inclination of satellite dishes, uses the same drives as the azimuth adjustment, but with an adapted transmission ratio. The interplay of the two adjustment systems is indispensable for exact antenna alignment.

Rigorous testing as a prerequisite for success

To ensure the precision of the azimuth bearing, Liebherr-Components subjected the bearing to the so-called "wobble test". At the site in Biberach (Germany), selected positions were approached several times, in order to measure and guarantee the greatest possible accuracy during operation.

Prior to market introduction, Liebherr subjects the prototypes to a comprehensive test programme, including stiffness tests, for the azimuth and elevation drives not only to meet, but to exceed highest industry standards. The expertise built up over decades is crucial for the symbiosis of the slewing bearing, gear rings and slewing drives as a unit.

With a commitment to set forth precision engineering and innovation, Liebherr and mtex antenna technology shape the future of satellite systems and push forward satellite positioning technology.