Robust joint and plain bearings in the heavy-duty e-cargo bike

E-cargo bikes form an extremely competitive growth market that more and more start-ups are jumping into. "We can only survive among these strong competitors if we continuously work out innovative solutions," says Wolfgang Hindel, Sales Director E-Mobility at b&p. A high payload alone is not enough. To deliver their goods as efficiently as possible, logistics operators want e-cargo bikes that are manoeuvrable, extremely reliable and low-maintenance. "We therefore designed our vehicle to be easy to manoeuvre and steer, and to withstand around 6,000km between service intervals. That is above average in our industry." To achieve this, the design engineers thought along new lines. Many parts do not originate from classic bicycle construction, but have been taken over from the e-scooter and motorcycle sector - including brakes, wheels and chains.
It was also necessary to rethink the handlebar bearing and find an alternative to conventional rolling or plain bearings made of metal. These were out of the question for several reasons: firstly, the edge loads would result in a constant risk of premature failure. Secondly, installation would be comparatively complicated: "We would have had to use additional encapsulation and sealing of the metal bearings to protect them from corrosion due to wind and weather," says Vincent Okroy, the vehicle's design engineer. And thirdly, retrofits and readjustments would be necessary to compensate for misalignments - time and effort that they wanted to avoid. At the same time, b&p was fundamentally committed to saving as much weight as possible in all components.

With parts from igus, several birds could be killed with one stone. The engineers chose a hard-anodised, coated igus aluminium hollow shaft as the handlebar, which is usually found in linear guides in mechanical engineering. It is mounted on an igubal spherical bearing of the EGLM-30-LC series. In it, the handlebar can move in a linear direction and up and down at the same time, and the front cross-member can thus pivot around the frame. This way, for example, a bike can ride on the curb without the frame twisting. Exact alignment of the bearing housing is not necessary because the bearing automatically compensates for misalignments and edge loads. It operates reliably at temperatures from -30°C to +80°C and is resistant to moisture, UV light and salt. It doesn't need packaging and seals that protect it from corrosion.
The spherical ball made of iglidur W300 material operates entirely without lubrication at the lowest coefficient of friction. The bearing housing made of igumid G polymer is extremely robust: it withstands a static axial load of 4,000N for a short time and a radial load of 17,000N. "A good plastic bearing can withstand what a steel bearing can," Okroy says. This is not only proven by tests in the igus test laboratory. "The bearings are strong and up to all everyday biking situations, even with a full load of 250kg. This has also been proven by our trial tests, in which the vehicle covered 80,000km with a full load." Last but not least, the igubal bearing scores with its low weight of only 26g. Comparable metal spherical bearings including enclosures and sealing, in contrast, weigh around 120g.

b&p also takes advantage of the low weight on the rotatable head of the attachable trailer coupling: the company uses iglidur X sockets with very high compressive strength.