Friction clutch in disc mower

Due to changes in agriculture, the demands placed on machinery and equipment for farmland management are constantly increasing. As a supplier of drive systems for agricultural machinery, GKN Walterscheid GmbH is constantly working on adapting its products to these requirements. In this project, an existing combined overload clutch (combination of friction clutch and freewheel clutch) was revised. This is used in a disc mower to limit short-term torque peaks.
The problem arises from the requirement for higher speeds of up to 1300 revolutions per minute. The standard design of the friction freewheel clutch is relatively backlash-prone, which leads to an out-of-round running behaviour at high speeds. As these couplings have already been used in many applications, it was important for GKN Walterscheid GmbH to create a solution with a new bearing concept that would enable a 1:1 replacement of the old coupling.
As the application in agriculture takes place under the most adverse conditions and the components are exposed to substances such as fertiliser, a robust solution had to be found. Added to this are high temperatures, especially in conjunction with a friction clutch.

The problem was to be solved by a completely new bearing concept in the coupling. Various interfaces were combined in order to improve the running characteristics of the coupling to the current trade show standard. To be able to remain in the same installation space with these measures, a particularly space-saving bearing was sought. Since initial experience with iglidur ® bearings had already been gained in previous development projects, a suitable bearing was quickly found. Thanks to the good support and the fast delivery of sample parts, the project was quickly brought to a successful conclusion.
The problems that arose during development were partly due to the relatively high temperatures that can prevail during use as well as the high sliding speeds. After an initial test with plain bearings made of the material iglidur® -Z, however, the joy was great, because the friction clutch now enables a significantly better radial run-out. And the iglidur®-bearing also delivers what it promises: low wear, good running properties, no corrosion and resistance to dust and dirt.