Gears, most wanted

[efferman]

because myself is actually in sickness to make some gears, which one would you like to have or, for purists, only to see?

planetary gears, torsen diffs or worms which can fit on 12 and 20 tooth gears?

anything else interesting in your mind?

[PhyBuilder]

Sag mir den ersten Satz, den du geschrieben hast, mal auf Deutsch. Denn ich hoffe nicht, dass du gerade so empfindest, wie es auf Englisch rüberkommst .

As for the gears: a common wish I'd had, is to have the current gears in multiple colors, especially the 16 tooth gearbox gears. This to differ the functions in complex gearboxes and -trains, but mostly because of the cool looks. Yellow, Blue, Light Blue, Orange...

[Cumulonimbus]

Not sure if there is added value in Technic, but I would be interested to see, feel and hear the difference between helical gears and the normal "spur' gears (the standard Lego gears with straight teeth).

In real life, these helical gears provide smoother and less noisy movement, for example: the noise most cars gearboxes make in forward (helical) gears is far less compared to the noisy reverse gear with spur gears.

A so-called Geneva drive or Maltese cross might be a cool way of gearing as well.

http://en.wikipedia.org/wiki/Geneva_drive

Finally, a harmonic drive would be very fascinating as a mechanism. They are a very compact way to realise high gearing ratio's. It might be a challenge to build though.

I don't have an application for it yet, but others might have ideas.

http://en.wikipedia.org/wiki/Harmonic_drive

[efferman]

@ phy builder, ich bin gerade süchtig danach zahnräder zu entwickeln.

different coulours are possible on shapeways

@ cumolonimbus the maltese cross should not to be a problem. but the harmonic drive does it use a chain or a belt?

two planetary gearboxes for frame mount coupled together, each one has a 4 to one reduction so this picture shows a 16 to one reduction. one gearbox is two studs long. do you think it would be better to make it one stud longer and have a crosshole, instead the 2 stud long axle, which is actually a weakpoint?

[PhyBuilder]

@ phy builder, ich bin gerade süchtig danach zahnräder zu entwickeln.

Ok, so you mean you are hooked to it, or the supremacy: addicted to it (depending on how bad it is )

[DrJB]

@Effe ... Look up harmonic drive by akiyuki. It does not use a chain. The oval (on the wiki link page) is essentially two rollers, that push a thin gear ring, to cause it to mesh with the internal large gear. One requirement of the harmonic drive is that the external gear (inside) be flexible in bending yet stiff in torsion. It is such deformation that allows it to mesh and rotate. Thus, the wall thickness must be very small. The first link shows this clearly. The third link is another interesting concept.

http://www.thingiverse.com/thing:20177

http://www.gtajp.com/data/sub2/sub2c.htm

http://www.thingiverse.com/thing:30615

[efferman]

hm, the third link is a simple multistage planetary gear like my picture above.

the first link shows clearly how it works. thanks for this

edit

i have modified the gear box and the planet cage

output

input

opinions?

Edited April 26, 2014 by efferman

[Hrafn]

28t double bevel is the only gear I'd want. Right now you can use the small turntable to simulate a 28t gear, but it's an awkward and bulky solution.

[efferman]

voila

28Z double bevel

[SNIPE]

Something to connect to these two:

Edited April 26, 2014 by SNIPE

[efferman]

There is an 18 tooth in the lego portfolio?

[Hrafn]

Something to connect to these two:

20t = 10mm radius; there is 3*8mm = 24mm between the two; so the new gear should have (24-10)=14mm radius and 28 teeth.

Similarly with the 16t (8mm radius): (24-8) = 16mm radius and 32 teeth.

A simpler calculation is:

Distance in mm between axles = average number of teeth of the two meshing gears.

[Cumulonimbus]

On a similar note: on a number of occasions, I needed a gear that makes this possibe:

[Nico van Duin]

Indeed, that would be very usefull, especially for using with a servo.

Edited April 26, 2014 by Nico van Duin

[efferman]

20t = 10mm radius; there is 3*8mm = 24mm between the two; so the new gear should have (24-10)=14mm radius and 28 teeth.

Similarly with the 16t (8mm radius): (24-8) = 16mm radius and 32 teeth.

A simpler calculation is:

Distance in mm between axles = average number of teeth of the two meshing gears.

there is many slack between 28 and 20 teeth. not sure if this works smooth

2820 von efferman auf Flickr

cumulonimbus, without any gear reduction?

[Captainowie]

On a similar note: on a number of occasions, I needed a gear that makes this possibe:

You could use 3x 8 tooth gears rather than 2x 16. However, if you're concerned about the axles being 1/32 of a rotation out, then the backlash in 3 gears might be too much for your application.

Owen.

[vmln8r]

Cumulonimbus: the 14-tooth gears do this when connected perpendicular to each other. Not sure if they reach each other in parallel. The 8t gear and the inner 24t of the turntable also work.

[efferman]

i think he want use it on grapples and similar things to syncronize them, without four bevel gears or let them work asymetric.

two gears with 17 teeths can do it

but because more narrow theeths and distances between them, it is not really compatible with standard gears

maybe on some uneven distances on bigger opponents.

uploading the 17Z?

Edited April 27, 2014 by efferman

[Jeroen vW]

Personally I would kill for a planetary gear with high reduction. Like the shown model with 1:64 ratio.

[Captainowie]

i think he want use it on grapples and similar things to syncronize them, without four bevel gears or let them work asymetric.

two gears with 17 teeths can do it

An alternative might be a 16-tooth gear with the teeth slightly mis-aligned with the cross-axle. This has the advantage of being able to be used in almost any situation you would need an ordinary 16-tooth gear.

Owen.

[efferman]

Owen, very simple and fully compatible. a genious idea

jeroen, i will look what is possible

[OzShan]

I'd also love to see a small harmonic drive. Maybe 4l thick and the diameter of an xl? No backlash and high ratio in a small package would be so useful. The output could be like a small turntable so you could build straight onto it. Too much torque for a shaft.

Edited April 27, 2014 by OzShan

[Boxerlego]

Trying to get purist approval of something very difficult. Consider this, even though I showed a modified a 16 tooth gear begin able to connect with a non-lego gear I still have a purist way by begin able to use a unmodified 20 tooth gear and still achieve the same thing but the purist mentality will not look positively on either one because it is no good to them. There will always be hostile attitude towards anything positive and new. Purist should be focused on the consistency, this is necessary for the sake of logic. What is good in the past will be good now and will be good in the future and it will be good under any circumstance, so any idea that does not cover all this broad base is no good.

Edited April 27, 2014 by Boxerlego

[efferman]

a 16 teeth gear with a crosshole which is rotated by a half teeth

OzShan

shapeways has a minimum wall thickness of 0,8mm. iam not sure if this is thin enough to be flexible enough in this size. i can make a mode,l but this is on the buyers risk.

[Zerobricks]

On a similar note: on a number of occasions, I needed a gear that makes this possibe:

You can do this with the use of pulley wheels, to rotate the axle by cca 60 degrees.