Gears, most wanted

[Rockbrick]

I think we can use the tube and the gears from this drawing (ignore the other parts)

in 100% lego it can only be done like this:

https://www.youtube....h?v=E_y5QkFoV8s

Edited May 15, 2014 by Rockbrick

[efferman]

what is the point in the video? that it has a diff?

and your left picture, the parts are not possible to produce. A cross axle has 4,7mm, a lego beam is 7,8mm thick. there is not enough space for two additional walls

[Rockbrick]

what is the point in the video? that it has a diff?

and your left picture, the parts are not possible to produce. A cross axle has 4,7mm, a lego beam is 7,8mm thick. there is not enough space for two additional walls

Nevermind the video.... forget the picture on the left also

look at the photo on the right and assume the tube parts have 'teeth' at the end... this gives you a tube that can be driven by the standard 16z round hold gear wheel with teeth (the old type)

or imagine some other custom part setup....

that is all the custom parts you would need to make this sort of inline diff:

The tube and the gear on the end of it have to move as one... inside the brown one spins independantly on the cross axle,

the rest is the diff mechanism and note the largest gear does not go onto the axle, it would be driven from the left or its teeth

Edited May 15, 2014 by Rockbrick

[efferman]

Its quite large isnt it? iam not a fan of solutions which takes more space as a standard piece. its better to use a standard 4L diff setup

tatra axle v2 von efferman auf Flickr

dont missunderstand me, the inline diff is an interesting concept and makes fun to make it lego compatible in a practical size

[SNIPE]

Herringbone gears,

Also maybe something to position the new 8 tooth gear so it meshes on a 90 degree angle to a 20 tooth double bevel gear or a 12 tooth double bevel gear (yes they mesh fine.)

[Hrafn]

I'd love to see parts for a true Torsen differential using helical gears.

[efferman]

Hrafn, look at this, or do you want it more compact?

herringborne? double helical gears?

[Rockbrick]

its about time lego brought out some helical gears....

[efferman]

i have found a way to make 8tooth gears without crosshole

i have made some 8 tooth sized helical gears and ordered it to test them

Edited May 16, 2014 by efferman

[Hrafn]

i have found a way to make 8tooth gears without crosshole

i have made some 8 tooth sized helical gears and ordered it to test them

Both of those look great! I hope the first ones are strong enough to withstand meshing forces. The helical gears look great, too!

The guy who made the other helical gears you linked to has used them in a Torsen, but it still looks a bit larger than I'd like. It may not be possible to go much smaller, though.

[efferman]

i think that the 8 tooth freespin are more solif than the standard 8tooth, because the weakpoint of the standard one is the thin wall between teeth and crosshole. on the freespins the 1,9mm thick sidewall supports the teeths. unfortunately the sidewalls eliminate the use with bevel gears

[OzShan]

They both look really good. Do you think the free running 8z would now be strong enough to make a compound sprocket with a 24z? You could then build high ratio gear trains on just two axles without resorting to worm gears. Especially now TLG is releasing axles with round portions specifically to reduce friction/wear on idlers.

Keep up the good work.

[efferman]

do you think this will work?

[Hrafn]

do you think this will work?

That looks great! Is there any reason you've only chamfered the corners on one side? How long are the helical gears - 2L? How would you drive the differential frame?

Every illustration of a Torsen diff I've ever seen also includes spur gears - the paired helical gears mounted to the diff frame don't mesh directly. Your version seems to make more sense, but surely there's a reason that the real-life ones add spur gears.

Edited May 17, 2014 by Hrafn

[efferman]

The helical gears have the same size and width like a standard 8 tooth. There is only one side chamfered because the other side gets a 36 tooth bevel gear.

I know that all type A torsen diffs have spur gears, but these need many space and i want fit the diff in a 5x7 frame. Theoretical the helical gears should work together without the spur gears, but practical i get a set of the gears at the end of the month and can test if it work. When it works i make a video and the diff complete.

[Hrafn]

The helical gears have the same size and width like a standard 8 tooth. There is only one side chamfered because the other side gets a 36 tooth bevel gear.

I know that all type A torsen diffs have spur gears, but these need many space and i want fit the diff in a 5x7 frame. Theoretical the helical gears should work together without the spur gears, but practical i get a set of the gears at the end of the month and can test if it work. When it works i make a video and the diff complete.

Ah, OK, that makes sense. f you can keep it compact by eliminating the spur gears, that would be awesome.

[efferman]

unfortunately it doesnt work

the vid shows 4 helical left and 4 helical right, but real torsen type A diffs have 8 helical right or left. now i can add spur gears and increase the diameter, or i add a third row helical gears and increase the depth ( min.260mm )of the diff. but everything i do, fitting in a 5 to 7 frame is history.

Edited May 18, 2014 by efferman

[efferman]

sorry for double posting, but the torsen diff works and fits in a 5 to 7 frame

[Zerobricks]

Awesome work! You think it could survive some torque? Like powered directly by XL motor?

[Hrafn]

sorry for double posting, but the torsen diff works and fits in a 5 to 7 frame

Great job! I really want one (well, three) of these now.

[efferman]

well zblj, the teeths of the spur gears are thick in relation to their height. so i think they should have no problem with the torque. I dont know how the helical gears are working in real life, but i think they will do their job.

hrafn, nice that you like it. i make it final.

[Sardo]

Wow very nice !! gonna get me a few of those

great work !

[efferman]

the torsen diff is online. hopefully it works like the simulation

[efferman]

someone on shapeways asked for a diff which fits to lego city tires. the diameter is only 15,8mm so it fits theoretical in a 2x2 box

Edited May 22, 2014 by efferman

[OzShan]

How about free-wheeling pulleys so you can make a 3 or 5 stage pulley system for hoisting crane hooks? They could all be mounted on the same axle and turn at their own rates without the string having to slip over them.

I had a look through you shapeways store. There are a lot of cool parts there :)