Components
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Unique production ­processes

Step by step from ring to slewing bearing: production processes that have it all​

Whether harsh environmental conditions, extreme installation situations, heavy loads or high radial and axial forces – slewing bearings must withstand the various environmental conditions, permanently and reliably. Unique production processes ensure that Liebherr slewing bearings are robust and durable in any installation situation.

Large slewing bearings, high vertical integration

Particularly in quality-determining production steps, Liebherr scores with a high level of vertical integration. This ranges from the machining and slip-free induction hardening of bearing raceways, through the gear cutting of slewing bearings, to surface coating in house. Professional know-how and modern machinery characterize the entire manufacturing process.

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Seamless hardening
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Seamless hardening for highest continuous loads and significant noise reduction during operation

Seamless hardening process for longer runtimes

Unlike conventional induction hardening, four inductors are used in the seamless hardening process. The so-called seam is avoided by oscillating movements of the two pairs of inductors and the preheating inductors. With a total of 800KW power, the metal is hardened to a depth of 8mm and then quenched. The result is a continuously hardened material.

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Superfinishing of the slewing bearing raceway for longer service life

Superfinishing refines the raceway surface of slewing bearings. In this process, the surface of the raceway is machined in such a way that the tribology with wear, friction and lubrication is optimized. This ensures an extremely high surface quality and an increased service life of the slewing bearings.

  • Longer calculated service life for high-speed main bearings (focus wind) than with hard turning and grinding according to the advanced method of ISO 281
  • Reduction of inlet wear
  • Significant increase in material content due to plateau-like surface structure
  • Defined, intersecting and precise machining grooves (cross grinding)
  • Uniformly guaranteed lubricant distribution

Take a look inside the production halls where a ring becomes a slewing bearing

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Special sealing for slewing bearings

Special sealing packages adapted to specific applications:

Different industries have different sealing challenges. Liebherr therefore relies on specially manufactured seal packages for slewing bearings. These are resource-saving and have a long service life. For example, the four-stage seal package for a thruster bearing eliminates the need for a complete replacement of the sealing system.

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Surface coating and corrosion protection

  • Sandblasting: In this process, chilled cast iron granules are blasted onto the rings at a blasting pressure of 8 bar to achieve a surface roughness for thermal zinc spraying and painting
  • Thermal zinc spraying: Protection against corrosion is provided by the thermal spray process with zinc (TSC) carried out in accordance with DIN EN ISO 2063
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