The metal planetary gearbox with a brushless motor

[Krzychups]

­­­­Hello folks! 

I want to present you my design of the metal planetary gearbox with the A2212 brushless motor (or other 28 mm diameter brushless motors). At the moment it is only a design (which can be modified), physically I have not got any part! Before reading, please read this topic (from this place) if you are interested in. You will understand it better. Unfortunately I cannot do the renders and animations, my computer is weak....

all parts by Krzysztof Czech, on Flickr

motor with planetary gearbox by Krzysztof Czech, on Flickr

Dimensions in studs: 5x5x10. The lenght is about 80 mm but it depends on the motor lenght (I do not include the shaft lenght which can be cut).

Parts: 

• the A2212 brushless motor,
• the 28 mm planetary gearbox for 3,17 mm diameter motor shaft,
• the metal adapter to connect it to the Lego axle.
• the 3D printed part with mounting points to connect it to the bricks,
• 10 screws (what type I will write later when I will have the planetary gearbox).

The planetary gearbox

Here is the link. Gearbox ratio is 1:5,2. I can use also 1:3,71 ratio or even 1:14 ratio (but this version is longer). Lenght is 31 mm, diameter is 28 mm. The gearbox from the fabric has got 20 mm lenght shaft, I need to cut it to 10 mm.

The metal adapter

To connect it to the planetary gearbox’s shaft use two M4 maggot screws to avoid no balance. Dimensions are in the photos:

the metal adapter by Krzysztof Czech, on Flickr

the metal adapter 1 by Krzysztof Czech, on Flickr

The 3D printed part with mounting points

I think I will print it from PCTG (no mistake) or PA+GF (nylon with glass fiber) but I need the hartened steel hotend.

I have modelled the design on this person’s design, my part is very similar. These ventilation holes are a bit strange, but I have designed them to use as little as possible support. I can redesign this part if needed. In my opinion I require to polish it (especially the back side of the part). If you have got any idea how to improve it, please write here.

all parts1 by Krzysztof Czech, on Flickr

all parts3 by Krzysztof Czech, on Flickr

Selling

If is demand, I will consider it.

 

Questions? Please ask.

[Ryokeen]

3 hours ago, Krzychups said:

To connect it to the planetary gearbox’s shaft use two M4 maggot screws to avoid no balance. Dimensions are in the photos:

Most motor shafts are D shaped so 2 maggot screws won't do much, might even make it worse. Think of it that way, the side that got the hole for the screw is also lighter as it got the hole. The tiny imbalance of the weight of the screw vs the material that would be there in the adapter is neglectable. That's why you screw on the motor and why the motos have longer shafts.

Also the + shape in the adapter is nice and Zene does it like that, but when i talked to some cnc operators they told me that it's actually not easy to make with the depth of 8mm(1 stud). They suggested either use electrode erosion(expensive) or use another shape. That's why my metal wheelhub adapters have an axle part.
The lego axle to axle adapters are actually quite strong, i use them in my main driveshaft to connect metal axles and not one broke so far.

All in all nice work so far :)

[Krzychups]

Thank you for your help!

17 hours ago, Ryokeen said:

Also the + shape in the adapter is nice and Zene does it like that, but when i talked to some cnc operators they told me that it's actually not easy to make with the depth of 8mm(1 stud). They suggested either use electrode erosion(expensive) or use another shape. That's why my metal wheelhub adapters have an axle part.
The lego axle to axle adapters are actually quite strong, i use them in my main driveshaft to connect metal axles and not one broke so far.

So far I have taken Zene's motor and it is very nicely done. It hasn't got any extra metal adapter (I really don't know how it would be made with 1 stud lenght), the + shape is build in the planetary gearbox's shaft. By the way I have found the planetary gearbox that Zene uses. Just look at the metal universal joints we use, they don't have the + shape like I have done, something like this would be better.

Edited July 22, 2024 by Krzychups

[Ryokeen]

I just meaned that milling a lets say 2mm in diameter and 8mm in depth shape(4 times the corners of the axlehole adapter) can get problematic :) that's all