More power in the pedal
Eletctric underway: Riding with bottom-bracket motor
The e-bike boom continues to grow! An increasing number of mountain, city and, most recently, gravel bikes are conquering our streets. In larger cities, e-bikes have long been part of the urban landscape. To ensure that these bikes also run with the help of electric power, they need a suitable drive system. Some insight into the work of our subsidiary Robert Schröder.
When it comes to cold-formed parts that drive vehicles, we at KAMAX are of course the right solution. Our specialist for precise machining (Robert Schröder Group) produces the matching bottom bracket shaft and the corresponding hollow shaft for such bicyle e-drives – this is where the level of power transmission is determined in part by the motor. These are central components for the mid-motor and thus the heart of the e-bike.
Bottom bracket shaft (top) and hollow shaft (bottom) in comparison
In the mid-motor or bottom bracket motor, the drive is located directly behind the bottom bracket. These motors are mostly used in the medium to high price segment. Due to the optimal weight distribution, the drive block and usually also the battery are close to the low center of gravity. This means that the driving characteristics of the e-bike are hardly affected by the additional weight and lead to a good driving experience.
The advantages of this type of drive are the direct transmission of power to the chain and a compact design. There is also a compact wiring and resulting from this, a low susceptibility to interference. All types of gears can be installed and front and rear wheels can be changed without any problems. All of these features lead to the fact that the demand for bottom bracket motor continues to rise.
DOUBLED PRODUCTION
We are also noticing this in the current order intake. While our colleagues in Wuppertal (Germany) currently produce several hundred thousand parts per year, André Casel (Managing Director of the Robert Schröder Group) expects this figure to almost double in the next four years. Our subsidiary also benefits from a clear competitive advantage. Compared to the competition, we have two technological areas of expertise in one hand: cold forming and precision machining.
Most other companies buy bar stock and refine. With our integrated process, we save 40 percent of material not only in transportation, but also in the manufacturing process. In addition, there are savings in machining, since the pressed blank is already very close to the final product. Robert Schröder itself can press wire in up to 4 stages (30 mm) – for larger diameters, the employees at the KAMAX headquarters in Homberg can help. Here we get up to 6 stages (36 mm).
Facts for technology nerds about the bottom bracket shaft:
Production: >400,000 bottom bracket shafts per year
Diameter of the raw material: 30 to 36 mm
Savings due to cold forming (instead of classical production): 40% material
Manufacturing tolerance: 15 µm
Concentricity: 20 µm
Hard turning: up to 63 HRC
The company manufactures other precise products for e-bikes, such as adapters, aluminum rings and other turned parts. As a group of companies, we are close to a rapidly growing market in the mobility industry outside the automotive sector.
The next time you go out on your e-bike, it’s less effort thanks to the bottom bracket shaft from Robert Schröder. Have a good ride!
KXpress
