When a mower of the brand Fella, Fendt or Massey Ferguson changes from transport position to working position and swings out the mower bar, iglidur plastic plain bearings play an important role. They guide the pivot axis and hold the sickle bar in position throughout its entire service life - under adverse conditions. In this application, the plastic bearings from igus have proven their ability for 20 years.
The market for which AGCO Feucht GmbH in Feucht near Nuremberg produces forage harvesting machines can be described quickly and concisely. Jochen Gnann, Director Supply Chain at AGCO Feucht: "We are present wherever grass grows. " Because where grass grows, farmers keep dairy cattle and use the 'green fodder harvest' as food for their cattle. In doing so, the correct ratio of concentrate and green fodder (as hay or fermented as silage) must always be guaranteed.
The machines from Feucht perform the three steps of green fodder harvesting: mowing, turning and raking. For all three tasks, AGCO Feucht GmbH manufactures a very extensive range of machines, from compact mowers for alpine locations (with a working width of 2.05 m) up to large area machines with working widths of up to 9.30 m (mowing), 15 m (turning) and 14 m (raking). There is a clear trend towards larger machines. Jochen Gnann: "There are fewer and fewer farms, but at the same time they keep more livestock. Therefore, the working widths of the machines tend to be larger. " This trend is favoured by the fact that more and more agricultural contractors are operating in many countries.
The components of mowers are exposed to extreme stress.
The brass bearings used by AGCO Feucht GmbH attracted dust and dirt to the bearing points due to the required lubrication. There was also an economic aspect, since the bearings had to be lubricated regularly. If the maintenance intervals for lubrication were not adhered to by the customer, the bearing point would become defective relatively quickly and the machine would fail.
With maintenance-free and lubrication-free iglidur plain bearings, the effort for maintenance and lubrication of the bearing points could be completely saved. Lubricant is therefore superfluous. In addition, the iglidur plastic bearings are more cost-effective than the previously used brass bearings. Savings were thus also achieved with the purchase of plain bearings.
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 engineering at the site is much older, precisely 100 years old: In 1918, the "Bayerische Eggenfabrik AG" was founded in Feucht and in 1921 the Fella brand was launched. Today, being part of a global group enables the company to create the conditions for international presence: from Feucht, the machines are delivered to around 120 countries.
An important design element, especially in the larger mower units, is the movable mounting of the mowing bars on the base frame. The beams are folded up in the transport position, on site they are hydraulically swivelled into the horizontal position. The bearing is supported by igus bearing bushings made of iglidur high-performance plastics with incorporated lubricants.
The fact that plastic is used at this critical point at least needs an explanation. Because the forces and conditions to which the bearings are exposed are more than unfavourable. The tractor travels over uneven terrain at speeds of up to 15km/h. The mowing tools encounter stones and other obstacles, which causes a heavy impact load on the bearings each time. Also the temperatures can be quite extreme and since mowing is always carried out when dry, high levels of dust and dirt are part of the environmental conditions. Added to this is the weight of the sickle bar, which also acts on the bearings.
All in all, one can imagine the bearing application as a continuous load test - which the igus bearings easily master over a very long period. "We have been using igus bearing bushings for years, have built thousands of machines since then and are very satisfied with this solution," explains Jochen Gnann.
There were several reasons for the substitution of the previously used brass bearings at the time: "A metal-to-metal contact among moving components is always difficult. In addition, we were looking for a bearing that did not require lubricants, because the farmer did not want to lubricate and in the very dusty environment this would quickly lead to strong dirt adhesion. " Apart from the technology, the economic efficiency also speaks for the iglidur bearing bushings: The market for agricultural machines is very price-sensitive, and the plastic bearings are more cost-effective than brass bushings.
AGCO Feucht GmbH uses iglidur plain bearings from igus not only at the critical connection of the base frame and cutter bar, but also - mostly in smaller installation sizes - at various other bearing points of mowers, hay turners and rakes. There is a simple reason why the picture shows greased bearings. The grease is only used by employees in production to facilitate the insertion of the shaft. During operation, the bearing points do not require any lubrication at all, over many years of rough use on the turf. Jochen Gnann concludes: "Small component - big effect. “
The bearing is only lubricated during assembly at AGCO Feucht GmbH to facilitate the insertion of the shaft.
An iglidur bearing bush guides the pivoting cutter bar in the base frame of the mower deck. Very high radial and axial loads occur, which the iglidur bearings have successfully mastered for years.
Jochen Gnann, Director Supply Chain at AGCO Feucht GmbH (right) in conversation with André Hock, Technical Sales Consultant at igus.