Lubrication-free plastic bearings in harvester mowers for over 20 years

Since 2011, the Feucht site has been part of the AGCO Group, which is one of the three largest agricultural machinery manufacturers in the world with around 20,000 employees, a turnover of around 7.5 billion US dollars and strong brands such as Fendt, Massey Ferguson and Fella. However, the tradition of agricultural technology at the site is much older, namely exactly 100 years old: "Bayerische Eggenfabrik AG" was founded in Feucht in 1918 and the Fella brand was established in 1921. Today, being part of a global corporation creates the conditions for an international presence: machines are supplied from Feucht to around 120 countries.

An important design element, especially for the larger mowers, is the movable attachment of the cutter bars to the base frame. In the transport position, the bars are folded up; on site, they are swivelled hydraulically into the horizontal position. The bearings are mounted using igus® bearing bushes made of iglidur® high-performance plastics with incorporated lubricants

The fact that plastic is used at this critical point requires at least some explanation. Because the forces and conditions to which the bearings are exposed are more than unfavourable. The tractor travels at speeds of up to 15 km/h over uneven terrain. The mowing tools hit stones and other obstacles, which exerts a heavy impact load on the bearings every time. Temperatures can also be extreme and, as mowing is always carried out in dry conditions, the ambient conditions include high levels of dust and dirt. Added to this is the weight of the cutter bar itself, which also affects the bearing.

Overall, you can imagine the spherical insert bearing as an endurance load test - which the igus® bearing easily masters over a very long period of time. "We have been using the igus® bearing bushes for years, have built thousands of machines since then and are very satisfied with this solution," explains Jochen Gnann.
 
There were several reasons for replacing the brass bearings used until then: "Metal-to-metal contact is always difficult with moving components. We were also looking for a bearing that did not require lubrication, as the farmer does not want to lubricate and in the very dusty environment, this would quickly lead to dirt sticking to the bearing." Apart from the technology, the cost-effectiveness also speaks in favour of the iglidur® bearing bushes: The market for agricultural machinery is very price-sensitive, and the plastic bearings are cheaper than brass bushes.