This 2 speed automatic gearbox design uses a worm gear for torque detection and gear switching combined. Some of my previous 2 speed automatic gearboxes have used a differential for torque detection to drive an orange rotary catch to switch gears using a switch component. The worm gear switches gears by disengaging one path to the input differential, thereby reducing the overall gearing ratio. In this 2 speed gearbox design the output gearing ratio is halved when switching from gear 1 to gear 2. By disengaging the 2nd path, the efficiency of the lower gear is improved due to the simplification of the gear train reducing the friction and power losses in that path. The overall power of the Lego technic automatic gearbox is demonstrated by testing it against a ten level torque generation device, as well as using a rubber band pulling instrument to measure the output pulling force for both gears.

Hope you like it.

 

 

 

Interesting idea. I like how you exploited a property of the differential that was disadvantageous to me because I wanted the input and output of my gearbox with differential to be reversible.

Regarding the new differential, how many teeth does the double bevel gear connected to the housing have? 

Also, does the torque detector using the worm gear work regardless of the direction of the rotation of the input? 

I think it only works in one direction as if you spin it the other way the worm will want to shuttle the in the opposite direction. I guess you could make a floating worm and have another gear, like say a crawler gear that engaged when you drove the motor the opposite way and put an extra cog in the chain to bring the drive back to the same direction, that would work like a kickdown when you reversed the input. 
or you could use the system to provide a realistic low reverse gear.

Good work! The size is much more reasonable on this one!

4 hours ago, 2GodBDGlory said:

Good work! The size is much more reasonable on this one!

Hi I knew you'd like this one better ;) LOL. As you know most of my builds are just proof of concept ideas. Once I have settled on something that works well I'd look at laying it out for a specific purpose - e.g. vehicle etc.

 

16 hours ago, Woodpecker said:

Interesting idea. I like how you exploited a property of the differential that was disadvantageous to me because I wanted the input and output of my gearbox with differential to be reversible.

Regarding the new differential, how many teeth does the double bevel gear connected to the housing have? 

Also, does the torque detector using the worm gear work regardless of the direction of the rotation of the input? 

 

No it doesn't work in reverse - most cars only go forwards LOL! The new differential has 28 teeth on the housing - it's pretty much a regular 28 tooth bevel gear. It gives another design option which is what I like about it.