A 125 ton "discus"
SKF is currently building a high-performance test platform in Schweinfurt. The 40 million investment will help large bearings perform much more precise and efficient test phases than previously possible.
The cylinders attached to the oversized "discus" are capable of developing enormous dynamic forces in the range of several meganewtons. This makes it possible to simulate all those loads that could at most be made possible in large bearings such as wind turbines. "For reasons of economy, such bearings should last 20 years or longer," explains Dr. Martin Göbel, head of the test center project at SKF.
"These 20 years - and all conceivable loads during this time - we will be able to reproduce very realistically with the new test stand in a period of just a few weeks." This not only saves a lot of time and money, but also energy - especially since the waste heat from the test stand is used by a heat recovery system. This is one of the reasons why the project is being funded by the Bavarian State Ministry of Economic Affairs and Media, Energy and Technology with around 1.9 million euros.
Innovative tests
For the highly efficient "stress tests", the hydraulic cylinders in the large test rig first act on the 125-ton disc that has just been installed. This in turn passes the corresponding loads on to the test specimen, which is attached to the disc by means of an adapter. "This is an innovative concept," says Göbel, "and it has a decisive advantage. Because the forces acting on the bearing to be tested are not limited by the 'inherent stability' of a load-exerting bearing."
The bottom line is that the 64 cylinders, in cooperation with the disc, can unleash forces across all axles that, in their combination, are even several times higher than those of the currently most powerful large-bearing
"This high-tech facility saves time, money, and energy, too."
test facility. In addition, the test rig manufactured by Augsburg-based RENK Test System GmbH will enable high rotational speeds - in relation to the size of the test specimens: up to 30 min-1. In doing so, it can test not only a single large bearing with an outside diameter of up to six meters, but also the complete bearing unit (including the customer's conversion parts).
Forces under control
The bases of the testing facility are part of a 3,000-ton foundation that is decoupled from the rest of the open and light-looking building - so as not to have any disruptive interaction with the building. In view of the massive substructure, the precision work at the interface between the bases and the housing bases is all the more astonishing: "As far as the evenness of the contact surfaces is concerned, we're talking about tolerances of a few tenths of a millimetre," explains Büchner, "over a distance of around ten metres!
go easy on resources
Göbel sums up: "The findings from the tests help to optimize existing service life calculation models with a view to achieving greater realism. On the other hand, these findings will, of course, also flow into our product development and contribute, for example, to optimising further bearing generations with the lowest possible weight and minimum friction in their closeness to reality. On the other hand, these findings will of course also flow into our product development and, for example, help to ensure that further generations of bearings can be tested in reality with the lowest possible weight and minimum friction for many customers: The SKF test center is taking its
in the middle of 2017.