Certain things should not be looked at separately from each other. Especially when they have to function together reliably. Drives with gear rims or slewing bearings, for instance, form such a unit. The two Liebherr product areas of drive technology and slewing bearings are located right next door to each other at the Biberach site. The coordination procedures are short, and people know each other. Over the years, the cooperation between these seemingly completely different disciplines has resulted in a knowledge resource that comes to light in direct, personal customer consulting. A perfect symbiosis of these two components in any application represents clear product advantages that cannot be exploited in this way, when viewed separately.
Tooth by tooth: a perfect harmony
"We check the requirements for the drive and slewing bearing components right from the beginning. Hence, we deliver a pair of drive and rotary element that ideally complements each other in the customer's application," explains Stefan Harsch, team leader application engineering from the Liebherr Drive Technology department.
In detail, this means that Liebherr drives are manufactured with the necessary profile and flank line modifications on the pinion. If necessary, this can be based on calculation and simulation techniques, such as the finite element method (FEM). They provide important information on the load capacity and gearing reliability and allow Liebherr to optimise the design of its components. This gear fit accuracy means that slewing bearings and drive pinions are perfectly matched to the load spectrum of the respective application. This accuracy is reflected by efficient turning with little backlash, which significantly extends the service life of both components.
The same applies to the materials used. The drive pinions and the ring gear of the slewing bearing are given a material composition that is an ideal match. It is neither too hard nor too soft and prevents material cannibalism, in which the components do not wear each other out.
Runs like a charm
Even the best tooth coordination needs good lubrication. It is not without reason that Liebherr is also regarded as a consulting expert, when it comes to the viscosities of greases and oils. Applying this knowledge, a technically well-matched product combination is created, that is simultaneously lubricated. In such a way failure due to tooth cracking with subsequent tooth breakage or minor metallic material chipping is reduced to a minimum. All factors together add up to a component pair that makes a clear contribution to significantly longer application availability.
Innovations from application experience
At Liebherr, this shared technical understanding of the application also serves as a source for innovation. Not only does Liebherr's own applications benefit from it, but also external companies that use Liebherr components in their machines. One example of a product innovation is Liebherr's patented tooth root safety geometry (TSG). This is a built-in predetermined breaking point above the pinion in the drive. The origin of this design lies precisely in application experience, coupled with foresight: in the event of a sudden overload, the drive should break in a controlled manner at the specified point. This is an additional safety measure in case the overload protection integrated in the drive should no longer be effective. In this way, the significantly more expensive slewing bearing, which takes longer to procure, is protected against tooth breakage and can remain installed in the application. Longer downtimes are therefore being avoided.
Less effort, more convenience
As always, time plays one of the most crucial roles in any project. As a business partner for component pairs, Liebherr stands out in terms of communication and coordination with shorter distances, as well as solutions from a single source. Manufacturing, assembly and modification of the component along with service offers at one location not only minimise effort, but also avoids possible design errors due to the simpler exchange of information and close cooperation.
With this cooperation and the resulting experience, Liebherr has already successfully implemented a variety projects.
