[MOC] Smooth transmission 2 speed automatic gearbox

[TechnicBrickPower]

Here I present a smoothly switching 2 speed automatic gearbox. The gearbox uses the "differential jam" phenomena to prevent reverse torque transmission during the gear switch over point, when the driving gearing can be momentarily disengaged. The gearbox automatically switches down by a ratio of 2/3 when the load on the output is sufficiently high by using a differential to detect the loading and to drive an orange rotary catch. This is a smooth transition due to the reverse path being only one directional.

https://youtu.be/h7j50GRm6Vc

 

[TeamThrifty]

Excellent as always - a nicely considered solution!

[JintaiZ]

Great solution!!!

[2GodBDGlory]

Neat! 

The size is the biggest turnoff for me, but you did make a small one too (presumably less smooth), so I guess you have all the bases covered! I like to see some innovation in automatic gearboxes--I feel that this is a ripe field for innovation.

[aeh5040]

That's amazing.  I still don't really understand how the magic one way mechanism works....

Edited August 29, 2020 by aeh5040

[ord]

On 8/29/2020 at 9:25 PM, aeh5040 said:

That's amazing.  I still don't really understand how the magic one way mechanism works....

 

Edited September 1, 2020 by ord
Removed

[TechnicBrickPower]

On 8/29/2020 at 12:03 PM, 2GodBDGlory said:

Neat! 

The size is the biggest turnoff for me, but you did make a small one too (presumably less smooth), so I guess you have all the bases covered! I like to see some innovation in automatic gearboxes--I feel that this is a ripe field for innovation.

Hi thanks for the feedback - I generally don't design with a size in mind - it's more the concept I am trying to demonstrate. For a particular application you may be able to redesign it to be smaller - there are a few gaps in the current design.

[lcvisser]

Very interesting and a useful application of the "magic" differential!

In case you missed it before: the "magic" is in the torque multiplication in the loop of gears. This multiplies the internal friction, causing the gears to bind up. If you drive the 16z-side of the differential with a 16z gear (instead of the 24z-side with a 8z), the effect disappears, without fundamentally changing anything in the gear layout of the setup! I have posted some analysis here: