Special bearings for agricultural machinery

Schaeffler has an enviable reputation amongst designers of agricultural machinery for providing reliable, high quality, maintenance-free bearing solutions

Heavy-duty agricultural machinery, including tillage and sowing machines, harvesters and tractors, must be designed to withstand extremely harsh operating conditions.

Key here is the selection of appropriate bearing supports and seals.

Harsh conditions such as dirt, dust, sand, high humidity levels, heavy clay soil and shock loads, all take their toll on the mechanical strengths of the machine components and seals.

Large machinery often involves high costs for regular bearing maintenance.

Indeed, specialist agricultural machinery contractors are now demanding such solutions for their equipment.

This explains the current trends towards incorporating maintenance-free bearing solutions and seals on agricultural machinery.

Components on a harvester, for example, have to cope with plant remnants and sap, the acidic contents of which can cause ingress of dirt, leading to possible seal damage.

On a corn harvester, high rotary speeds lead to high mechanical stress on the bearing; contamination and aggressive, acidic corn sap affect the seal.

To solve these problems, Schaeffler has developed a ready-to-fit bearing unit with triple-lip sealing.

Similar to automotive wheel bearings, flingers can also be offered as an additional protective measure against ingress of dirt and other contaminants.

These components are pressed onto the rotating inner ring, using centrifugal forces to transfer contamination away from the bearing.

Schaeffler double-row angular contact bearings transmit loads through a solid housing into the adjacent structure.

The bearing has an additional grease chamber, which protects the bearing from dirt and corn sap.

The spherical bearing outer ring and the counter-shaped surface in the housing compensate for any misalignment in the adjacent structure during shaft mounting.

Similarly, tillage machines that are used to prepare the field for seed planting also require very robust bearing supports.

The bearings are combined with suitable flange housings, which simplify installation.

In plough discs, for example, the inclined position of the disc results in transverse forces and bending moments, as well as radial loads.

For these applications, Schaeffler offers double row angular contact ball bearings or robust, four-point bearings for applications with limited space.

Robust ball bearings are also offered for shaft supports.

For seeders, where the forces involved are lower, Schaeffler offers smaller bearing supports, as well as corresponding solutions for combinations of tillage and seeding machines.

* Bearing solutions for tractors.

Increasing working speeds and the higher performance capacity of tractors means that drive and power transmission units are subjected to higher stresses, which places higher demands on the bearing arrangements.

For these applications, Schaeffler offers both standard bearing units and custom designed bearing solutions.

On tractor engines, for example, under its INA brand, Schaeffler offers various belt drive components, such as tension systems and over-running clutches, water pump and fan bearings.

Together, the Schaeffler INA and FAG brands offer a wide range of bearings for applications in gears, power transmission systems and axles.

This includes needle roller bearings, drawn cup needle roller bearings and needle roller cages, machined or manufactured by forming methods.

Schaeffler premium quality 'X-life' range of bearings boast improved surface and geometrical accuracies, resulting in increased service life.

Full complement needle roller bearings are offered for maximum load carrying capacity in tight installation spaces and needle cages with a special, profiled 'KZK' cage is used in high acceleration applications.

Similarly, cylindrical roller bearings with different cage designs (and as full complement variants) with or without outer ring are other important components for the tractor drive train.

Schaeffler X-life tapered roller bearings with large contact angle, can be used for high load applications, with various heat treatment and material coatings available.

These types of bearings are often used in transmission-integrated hydro engines, pumps, in pinion bearing arrangements and rear axles.

For the interface between engine and transmission, Schaeffler can provide its LuK branded clutches, which incorporate specially developed clutch release bearings.

Here, effectively sealed bearings with drawn outer and/or inner rings are used, which enable cost-effective overall designs, while offering high reliability and extended service life.

For supporting slewing, tilting and for the alignment of chassis movements, axle suspensions and load harnesses, Schaeffler spherical plain bearings and rod ends are ideal.

Spherical plain bearings with complex lubrication groove systems on the outer ring can be used in combination with spring-dampened front axles and chassis.

Stabilisers, damping and hydraulic cylinders are fitted with spherical plain bearings and rod ends.

For example, Schaeffler Elgoglide maintenance-free, heavy-duty spherical plain bearings are used in the wishbone systems of front axles with independent wheel suspension.

Maintenance-free Permaglide cylindrical plain bushes can be found in door hinges, engine hood supports, lever sets and rod systems.

* Radial insert ball bearings.

In agricultural machinery, housed bearing units are often used to compensate for static angular misalignment of the shaft of up to 5 degrees for non-lubricating units.

The housing bore and bearing outer ring are spherical in shape so that the radial insert ball bearing can align itself in the housing.

In conjunction with the different housing types (cast iron and sheet steel), Schaeffler radial insert ball bearings form complete units, offering significant rationalisation options at the design stage and during customer manufacturing/assembly.

Numerous combinations are possible for every application.

Radial insert ball bearings come with a choice of five seals.

Most seals comprise three pieces and are made from zinc-coated outer and inner steel plates with rubber sealing ring.

This prevents ingress of dirt and humidity, while also ensuring the required elasticity and preload of the seal, even after a long period of operation.

The deep drawn outer steel plate protects the sealing ring against mechanical damage.

Bearings with R-seals have a larger grease reservoir due to sealing shields that are bent to the outside.

All sealing concepts comprise evenly and concentrically abutting rubber lips for increased bearing life, as well as firmly rolled inner and outer caps to ensure easy re-lubrication.

Schaeffler Corrotect coating can be applied to its radial insert ball bearings, offering customers a corrosion-resistant, low cost alternative to stainless steel bearings.

The inner rings and locking collars are coated against fretting corrosion as standard, which also prevents rust formation at the sealing lip.

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