Cool, that is interesting. I wonder if this is a personal project or whether it is going into production.
Google translate says:
"I can not speak English
Mechanical structure: level 1 Gleason gear, level 2 to 3 helical gears, gearbox requires angular contact bearings, mechanical parts will not have too many problems, the key lies in electronic parts, including speed sensor and bottom axis torque sensor, 12 magnetic The point double Hall speed sensor is placed inside the big gear. The bottom shaft torque sensor has encountered some problems but has a new idea. It collects signals through the Hall chip."