How DJI Extracts Huge Torque From Its Compact Ebike Motor

DJI Enters the eMTB Market with Innovation

DJI, widely known for its drones, entered the electric mountain bike (eMTB) market this year with the DJI Avinox Drive system. We wanted to highlight the clever inner workings of this setup, which brings innovative features.

The 800-watt motor weighs just 2.52 kg (5.5 lb) and delivers an impressive 105 Nm (77.4 lb-ft) of torque. For comparison, eMTB motors from brands like Bosch, Yamaha, and Shimano max out at 85 Nm (62.7 lb-ft) of torque.

It seems DJI is aiming high, perhaps even for the stars.

The 2-stage drive system uses a compound planetary gearbox with a 40:1 gear ratio. The initial stage, with a sun gear and three polymer helical planetary gears with metal cores, increases the torque by about 3.2 times. The polymer helps reduce noise and extends the system’s lifespan. Helical gears were chosen over standard ones to improve load distribution and decrease operating noise.

Next, the outer ring gear meshes with the inner metal planetary gears, further increasing the output torque by 16.3 times. And that’s just the first stage. The second stage, which looks like a standard gear set, adds another 40 times to the final torque. The system’s final drive is connected to a one-way clutch that assists the rider when pedaling.

“Expanding into this field was a natural step for DJI, as we have mastered the essential technologies for an electric bike system, from reliable motor development, battery management, to mechanical design and engineering,” said Christina Zhang, Senior Director of Corporate Strategy at DJI.

Read the original article on: New Atlas

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