CROSS ROLLER BEARINGS IN MECHANICAL TRANSMISSIONS

Hi all, i was watching this animation of a planetary gearbox, and this doubt appeared, Hope, you can answer.
What is the Cross roller bearing for in this type of transmission? It is shown in the minute 1:03

I mean, why not to use a copling sitem directly to the system? After all, in the output of the transmission is where you can find the wished torque right? Wich then is passed to the cross roller bearing, but why? why not use it directly as i said?

As you can see, i'm digging into mechanical transmissions.
Thanks for aswering!.

https://youtu.be/sO1FhoUPjiE.

Hello Brian - The crossed roller bearing is used to isolate the moments and external loads from the gearbox. A harmonic drive uses very elastic ring gears that deform slightly allowing more teeth to engage (hence removing backlash) then a rigid design gearbox. If you attached the drive directly to the output shaft it would wobble quite a bit and the backdrive forces would damage the gearbox. Its the same on a normal gearbox a large bearing is used to isolate the external forces (backdrive moments, torques and forces) from the gearbox. If it was a power drive only gearbox some deflection and wobble in the system would be acceptable as long as this did not contribute to shorten the life of the gearbox. In a positioning system it is exceptionally important to have a rigid output shaft so minimal deflections are produced hence the use of a cross roller vs say a deep groove or angular type bearing. Cheers Peter

The bearings in the video should be the cross roller structure of the harmonic reducer special bearings, about the crossed roller bearings and harmonic reducer bearings related product performance and parameters, you can refer to here https:lkpbearing.com