DJI, which nearly everyone knows as the drone company, made the jump into the electric mountain bike (eMTB) sector this year with the DJI Avinox Drive System. We just wanted to show you the clever inner workings of the setup, which brings some unique features to the table.
The 800-watt motor weighs a mere 5.5 lb (2.52 kg) and puts out an incredible 77.4 lb-ft of torque (105 Nm). For reference, Bosch, Yamaha, and Shimano all have eMTB motors putting out 62.7 lb-ft (85 Nm) max torque.
DJI is making a swing for the fences, it seems. Or maybe for the stars.
The 2-stage drive system uses a compound planetary gearbox with a gear ratio of 40:1. A sun gear – along with three polymer helical planetary gears with inner metal gears – starts by boosting torque output by about 3.2x. Polymer is used to reduce noise and extend service life. The choice to use helical teeth instead of standard teeth was made to improve load distribution and to reduce operating noise.
The outer ring gear then meshes with the inner metal planetary gears, boosting output torque by another 16.3x. And that's just the first stage. The second stage, which looks like your basic run-of-the-mill gearset, adds an additional 40x torque output. The final drive is connected to a one-way clutch that assists the rider in pedaling.
"It is a natural move for DJI to expand into this field as we have been mastering the technologies essential to an electric bike system, in terms of reliable motor development, battery management, mechanical design and engineering," said Christina Zhang, Senior Director of Corporate Strategy at DJI.
Check out the video below, which breaks everything down.
Source: DJI
