Supports with compact, dirt-resistant iglidur P plain bearings secure uniaxial electric wheelchair from tipping over

Glide in order to roll: lubrication-free igus bearings increase safety in off-road wheelchair
Supports with compact, dirt-resistant iglidur P plain bearings secure uniaxial electric wheelchair from tipping over

To make it easier for wheelchair users to travel off the beaten track, HOSS Mobility GmbH has developed a self-balancing electric wheelchair without front wheels. Supports are used to ensure that this does not tip over even without a power supply. They can extend quickly in an emergency, which heavily stress the bearings. Therefore, the developers rely on igus bearings made of iglidur tribo polymers. Since they are compact and resistant to dirt and shock, they are ideal for use in the support structure.

Wheelchairs help people with reduced mobility to freely move about in everyday life. Off the beaten track, however, many wheelchairs reach their limits. Small front wheels sink into soft ground and impede progress. Large front wheels increase the turning radius and reduce agility. HOSS Mobility GmbH has developed the “HOSS”, a wheelchair that does not need front wheels. The principle is familiar to the Segway Personal Transporter: an electronic control circuit keeps the wheelchair in balance through small movements of the two drive wheels. When the wheelchair is not in use, extendable supports prevent it from tipping over. To ensure the safety of the occupants at all times, the supports can extend in an emergency in just 100 milliseconds, for example, if the tyres lose traction or if the battery is empty. The high loads that result from this, with up to 5,000 revolutions per minute, pose a severe challenge for the bearings, as does the compact installation space. Also, a low weight is necessary because every additional gram reduces the battery life. For this reason, the designers rely on iglidur P plain bearings from igus. These are compact – 1 millimetre wall thickness with 12 millimetres inner diameter – but still hold loads up to 50 MPa. As a result, they resist the impact on the ground when the supports extend quickly.

Improved wheelchair and plain bearing for outdoor use

A wheelchair without front wheels does not sink into sand or earth so easily, nevertheless dirt accumulates at the bearing points during off-road use. The iglidur plain bearings are made of tribo polymers. They contain solid lubricants which need no additional lubrication through oils or grease. Sand, dust or earth cannot adhere and block or damage the bearing. Even rain or snow poses no threat to the corrosion-free iglidur P material. This makes the bearings very long-lasting and maintenance-free. Lukas Rigler from HOSS Mobility GmbH is convinced of the igus plain bearing technology: “We are so satisfied with the iglidur plain bearings in the emergency support that we are also relying on igus in the attenuated seat, the back shell and the removable armrest.” These applications also feature minimal maintenance and maximum service life with small size and low weight.