OT - Plain Bearing Material Problems

You may get a good answer from this group, but I'd urge you to post also in "sci.materials" and "sci.engr.metallurgy". You're almost certain to get some very expert opinions there.

Mark 'Sporky' Staplet>

Hi Simon, use aluminum/bronze for the bearing, I used to work on Nuclear Fusion site in Oxford, England, we only used non magnetic materials and always used stainless/aluminum bronze combinations. Aluminum bronze has very high point contact load properties. Another good material for a self lubricating bush is phosphor bronze but there are health restrictions in the machining of the material.

Simon,

If the assembly needs to run un-lubricated and with low stiction, you may want to consider a plastic bearing (eg Teflon, or one of the bearing grades of Nylon). Look at printers / photocopiers around the office for typical exaples. If heat and / or load are too high for a plain plastic bearing then look at commercially- available sleeve bearings (bushes) such as Permaglide, which are available with a Teflon-impregnated sintered surface.

Rick.

Ditto, totally agree. And/or suggest using rulon, peek, torlon, uhmw pe or delrin, depending on the conditions, as well.

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"R.H. (Rick) Mas>

You might find something in the IGUS line that would be suitable.

Art W.

While I am no expert, we have also used Nylatron in similar situations.

This is probably overkill for your low load, low speed application. I suspect some UHMW would work pretty well.

I have prototyped both Oilon (oil impregnated Nylon) and delrin bearings. The problem I found was due to the fact that the assembly was so small, the machining proved difficult, the burr left behind effected the rolling resistance or the required break edge affected the end float beyond limits. I require an external running surface of stainless and cannot have a fully plastic wheel. That has brought a thought that maybe I could run with a Plastic shaft!!! This assembly is to be used in the clothing manufacture industry and therefore quite a dusty and dirty environment, this has lead me away from lubricants!

Simon

Sounds like a S/S wheel/roller with a Permaglide bush running on a S/S or hard chrome shaft might be the answer. If possible, protect the bush against ingress of lint, dirt etc.

Another thought is to use a shielded ball-bearing race in the roller - NSK, for example, have shielded metric-series miniature bearings in 3mm bore (MR63ZZ, 683ZZS ...) which might also be a viable solution.

Rick.

Simon, Check out someone like IGUS

Kev

Yeh, I was not necessarily thinking of oil impreg bearings or them being machined,.. more towards something w/o oil impreg or injection molded bearings (but can also machine,.. your burr problem sounds like a machining/quality issue).

Without fully understanding the design I think we are giving you any suggestion we can so...

Knowing it will be in a lint environment, where a dry bearing is preferred, and as someone noted, using wipers and sealing areas are worth it. Someone also mentioned ground or hardened sstl shafts, that should be used. Now, you're considering a polymer shaft? (electro static conditions may arise attracting more lint) Hmm... some of the high glass filled shafts are probably the only ones I can imagine for torsional use.. 3mm dia extrusion possible... ?

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SGM Design Ltd wrote:

My first port of call was the ball bearing (OD6 x ID3 x W2). It failed on two counts really, the stiction was quite high, which surprised me and the noise level was unacceptable. The device that these roller assemblies fit into is a hand held injection moulded case and seemed to amplify the bearing noise, hence the change to plain bearings.

SKF has a plain composite bushing/bearing ....stainless steel backing with ptfe coating inside...not sure about if they are avaliable in such small dimensions though

Krister L

Simon Miller skrev i diskussionsgruppsmeddelandet:btc868$rc4$1$ snipped-for-privacy@news.demon.co.uk...