Backlash free rotary table

[Azalin]

I'm designing my cycloidal drive. This is how it looks now. Pins are 5mm. Thoughts?

[RCaffin]

Hi Azalin

Well, it's not that simple of course.

First of all, what are the 5 mm pins made of? Ordinary mild steel? or maybe hardened HSS? Very different things.
What is the big gear wheel made of? Will it run dry or in an oil bath?

How thick is the big gear, and how thick is the support disk behind the big wheel? If the support disk is too thin it may flex or the pins could become loose and wobble.

5 mm is not very strong, but there are a lot of pins around the edge, so maybe that is OK for strength at the edge.

You have only 5 pins in the middle, and that is not so strong. Could you increase these to 6 or 8 mm?, or could you increase the number?

Anyhow, a lot of this will depend on what loads are going on the drive. If all it is doing is rotating slowly for positioning, no problems, but if you are spinning it at 2,000 RPM and putting 2 kW through it - very different!

Cheers
Roger

[Azalin]

Hi Roger,

Pins are hardened and ground. For the first version I'll cut the disc from aluminum but the final version will be steel probably. 10 or 15mm thick. I'll use two discs by the way.

No problem increasing the pins in the middle.

[mactec54]

I'm designing my cycloidal drive. This is how it looks now. Pins are 5mm. Thoughts?

This is a very old thread you should start a new one, Cycloidal drives are great, here are some builds specs that you may get some good information from

There are many videos on YouTube as well

[RCaffin]

Hi Azalin

Hardened and ground pins are good.

An aluminium disc will have very short life unless you use cast aluminium tooling plate. That is MUCH harder.
Alternately you could consider brass: rather $$ but a much longer life for testing before you go to steel.

If you use HSS for the pins and brass for the disk, you could braze the pins in place. The HSS will handle that.

Mactec is right: a new thread might have been a good idea, but ... we are here now.

Cheers
Roger

[mactec54]

Hi Azalin

Hardened and ground pins are good.

An aluminium disc will have very short life unless you use cast aluminium tooling plate. That is MUCH harder.
Alternately you could consider brass: rather $$ but a much longer life for testing before you go to steel.

If you use HSS for the pins and brass for the disk, you could braze the pins in place. The HSS will handle that.

Mactec is right: a new thread might have been a good idea, but ... we are here now.

Cheers
Roger

Cast aluminum tooling plate is softer than regular 6061

Most use a needle roller bearings or regular ball bearing for the rolling element

Here is a video using a bronze bushing as the rolling element

[RCaffin]

Hi Mactec

I stand corrected about tooling plate - thank you.
However, some cast Al is much harder than ordinary 6061. I have some offcuts from a propeller off a Hecules transport (damaged), and that stuff is HARD compared to 6061. What was the alloy and what was the heat treatment? Dunno. But it ate any 6061.

Neat video.

Cheers
Roger

[Azalin]

Hi again,

Opened a new thread here https://www.cnczone.com/forums/linea...-4th-axis.html