Which is the right plain bearing for sheet metal applications?
Ordinarily, plain bearings are intended to be press-fitted into relatively thick-walled structures such as housings. These housings normally have a tolerance on the bore and tolerance on the shaft. It is, however, a different story with some thin-walled components, such as the igus® clip bearings. These bearings are designed specifically for fitting shafts through sheet metal applications and can be difficult to press-fit, but not impossible. Here are some basic tips to follow, to not only correctly select the clip bearings, but understand that best way to install them.
Where to start….
The first thing that needs to be correct for installation is the bore within the sheet metal. Maintaining tight tolerances on sheet metal is often difficult due to the production methods. As a rule, these holes are either punched or lasered without additional post-processing so no de-burring of the edges. This results in sharp-edged contours and in some case, dubious tolerances. Sharp-edged holes are not ideal for plain bearings. To eliminate damaging the bearing, the best thing to do is to chamfer the edges of the bore lightly or deburr them. The tolerances won’t improve unless the holes have a secondary operation which is usually a process that is simply too expensive for many sheet metal constructions to consider.
Securely fasten the slide bearing
If the tolerance isn’t a H7 fit in the sheet, it becomes unstable when combined with a bearing. Similarly, If the overlap of the bore and bearing fit is not sufficient, the bearing will not remain within the bore and the shaft therefore will run directly through the hole, without the protection of a bearing, causing noise & wear issues on the shaft. With the igus® double flanged clip bearing, the bearing is securely placed in the bore thanks to its flexible and yet stable material formula and is secured within the sheet metal, both sides, with the second flange keeping it fixed into position.
Consider all environmental parameters in the design
There are always considerations at the designing stage. Does the bearing come into contact with food? Is it exposed to high temperatures? The decisions then become more about the correct material selection rather than how to install the bearing. Polymer plain bearings are regularly used as an alternative to metallic bearings due to the fact that they are corrosion-free, require no lubrication and are more cost-effective.
Off-the-shelf solutions and custom options
iglidur® M250 clip bearings can easily be utilised in applications using sheet metal. The material has the flexibility and yet is extremely durable. This allows the bearings to be manipulated into the hole and regain its shape and structure. The material compound is perfect for dirty environments so no issues with dust and general dirt.
Another standard material is iglidur® A230. These are FDA- approved and also EU10/2011-compliant so suitable for food applications. Again, like the M250 material, this material is flexible and yet dimensionally stable.
If an application requires a high temperature and chemical-resistant material, then the iglidur® K250 is ideally suited to such applications. This material has a low moisture absorption, offers even more flexibility than that of the M250 counterpart and is also suitable for cathodic dip coating so, perfect for the automotive industry.
However, If the standard range of bearings do not offer the correct solution, the large range of igus® iglidur® bar stock and plate allow custom parts to be machined to the specification of the customer, and for those super high tech requirements we can offer special designs using our SLS 3D printed materials.