[Nava]

A while back I got myself a harmonic drive off ebay ..actually a new one for dirt cheap. It was from a new other DENSO robot so I asked them what grease they used for it and apparently this stuff must be made of gold as they wanted 500 bucks for .5kg of which I would need about 20grams

Anyway if anyone has any idea of where to get some smaller amount or an alternative suitable grease I would love to know about it.

the one they recommended was called
Harmonic grease 4B-No.2

Attachment 382380

[awerby]

The problem is that harmonic drives have rubber gears, so there's a danger of damaging them if you use regular grease, which often is corrosive to various types of rubber. If your device doesn't absolutely need new grease, I'd say leave it alone.

[Nava]

Thanks Andrew, sadly it needs grease. Where are the rubber parts?

[Bdrangdo]

As a last resort you could use either silicon grease or rubber grease like the grease that is used for car brake cylinders. Both are inert as far as rubber components go though it may be too thick. Dave

[Nava]

I wouldn't mind forking out some money for it but just not what I was quoted. I did find a supplier for the one of the other types but its not what I was recommended.
https://www.rmhoffman.com/store/p76/...onic_SK-2.html

Still im not sure I see any rubber parts in this drive..the flex spline and the teeth are metal or am I missing something here

[RCaffin]

Hi Andrew

The problem is that harmonic drives have rubber gears,
They do?
Not as far as I know! Hardened SS, yes, but the only rubber in an HD is in the seals.

Frankly, I see little reason why one could not use ordinary EP grease.

Cheers
Roger

[awerby]

Roger's right; the gears in those reducers aren't made of rubber but they do have rubber O-rings. I'd still suggest using the lubricants they specify, on page 16 of this catalog: http://www.harmonicdrive.net/_hd/con...er_catalog.pdf , depending on the conditions it will be run in. If you can't find it or it's outrageously expensive, you might try asking them if EP grease or whatever you can find will work.

[RCaffin]

After all, Viton and Neoprene (and most if not all other common O-ring formulations) are compatible with just about any grease you can think of.

If you are going to be running your HD under extreme conditions - near max speed or loading, or in a vacuum, (or the lot!), then some care must be taken. But if you are using your HD to make a small rotary table or similar, then conditions are quite benign.

Cheers
Roger

[Nava]

Roger you kinda guessed it.. this is for a 4th axis for my cnc machine No rubber seals on this one yet as its just the 3 component gear set without bearings in which I will makeup a spindle for using some nachi angle roller bearings. Should give me a great resolution and quite high torque along with a decent servo. build pictures in another thread once its come along a bit.

[RCaffin]

Hi Nava

See http://www.cnczone.com/forums/linear...gineering.html for some ideas.

Cheers
Roger

[Nevency]

Look for greases with NLGI grades 2 or 3, extreme pressure (EP) and high temperature resistance. Some popular brands include Mobil SHC 1000, Castrol Tribol GR 222, and FAG Multilube EP 2.