User reportPlastic bearings in a remote-controlled tracked vehicle: robust in difficult terrain

The XRV-05 is a remote-controlled model vehicle powered by two brushless motors. The special feature of the prototype: The RC vehicle is a tracked vehicle that was built for particularly adverse environmental conditions. This is because the 1:5 scale model is not only used outdoors, it is also designed to operate smoothly at high speed in rough terrain.
When designing the XRV-05, attention was paid to a robust construction, whereby the choice of materials also played a role. After all, the off-road vehicle should continue to drive reliably even in dust, dirt, mud, rain and even snow. The built-in bearings in particular are a limiting factor here. The bushings, for example in the shock absorbers of the remote-controlled car, are quickly damaged under adverse conditions and therefore have to be replaced or cleaned frequently. While metal bushes would make a good hard-wearing solution, they rust extremely quickly in wind and weather. Another disadvantage of the material: if two different metals are used that come into contact with moisture, electrolytic corrosion quickly occurs.
The aim was to find an alternative to metal bearings that would reduce maintenance work and operate with as little friction as possible, even under heavy loads.

For the XRV-05, sliding inserts made of brass were originally planned for tensioning the chains. However, shortly before the first prototype was manufactured, it was decided to use low-friction plastic. The same procedure was followed for all other bearings. This included the choice of track bushings, for which bearings made from the high-performance polymer iglidur® were used. The second prototype also had shock absorbers for greater force absorption, which were placed inside the vehicle for greater durability. The swinging axles also had to be mounted for this purpose. And the iglidur® bearing products were also used instead of metal bearings for the upper and lower shock absorber mountings. The advantage of the iglidur® material: It is durable, resistant to dirt, free of corrosion, has shock-absorbing specifications and is also particularly light. The friction-optimised material can therefore also be used under high loads in continuous operation.
For the shock absorber, for example, two bushings made of iglidur® G were used at the top and bottom (Part No.. GFM-0608-04) and washers also made of the material iglidur® G (GTM-0612-015). There are also two shaft sealing rings between the guide elements. This combination allows smooth linear movements, watertight shock absorbers and high wear resistance.