Could anyone help me on bearing lubricant design?

Does the shaft rotate fully? At what rpm?

What are the environmental conditions the bearings are in? You said they corroded - how? What material are they? Do you use grease or anything now?

the shaft is always very slowly and irregularly swinging (rotate clockwise to some angle and return).

the bearing is made of nodular cast iron.

in the assembly,the mechanism is greesed.

the device is working in the moist and dusty air.

when the device was disassembled, many black spots could be found on the surface of the shaft.

What is the access like to these bearings? Would it be possible to install grease nipples/grooves/lines to the bearings and periodically grease them?

It sounds/looks like in your case there was grease initially applied but then there was no more injected. Is that correct?

yes, you are right. the device always was greased initially. since I thought the carbon element of the nodular cast iron can lubricant the device, then there was no more grease injected. apparently, my viewpoint is wrong, so I am seeking new method to solve the problem. however, I do not know what solution is better, and how to do it.

Not sure of details of your use, but I have found Vesconite to solve many similar problems. http://www.vesconite.com/

Hello

The materials couple of your bearing could operate satisfactorily having the following:

- install a sealing as a simmering on a bearing to protect it from outside agrressive environment;

- to do a periodically replenish of bearing grease install a regrease equipment as a SKF SYSTEM 24.

Hope this help

it is a pratiseful suggest. I will discuss with my colleague about it. thank you.

my colleague is very willing to use some kind of non_metal self-lubricated material.

however, we can not find the appropriate non-metal material with both higher strength and better lubricating performance. could anyone recommend a kind of non-metal material and give some information.

Try the bushings from IGUS very good results! You have also a on-line calculator to determine best material choice and wear evolution versus time (or cycles). The bushings can be highly loaded.

maybe, that is what i want. could you paste a website of IGUS? could you tell me where i can find the calculator? thanks

http://www.igus.com/iglide.asp

I would be careful with shock loading though - Is there much impact or shock on the shaft?

in fact, there is some impact or shock onthe shaft. sometimes the draft load can get up to about 100-200kN, at other time, the load suddenly (a few seconds)becomes push load and can get to about 100-200kn.

the impact or shock is irregular and load peak always waries.

"a few seconds" - that doesn't sound like much of a shock/impact load, more like a load reversal.

this device is used in the railway vehicle. the impact i meant is just the train longitudal impact. from draft to push situation, the reversal intervals are not same, sometimes the reversal process is long but at other times, the process is very very sharp and dynamic load is high enough.

I would discuss it directly with the Igus guys -

http://www.igus.com/show_intl.asp

Here is another supplier you could try

http://www.thordonbearings.com/products/polymer.html

you are so kind, i am very grateful for your help. thinks

A sealing arrangement should be provided to keep the environment out, lubricant (if used ) in.

If you desired to keep metallic bearings: perhaps if the rod eye was bushed also & a simple pawl arrangement provided so the pin were to rotate slowly... Would distribute wear + circulate lubricant.

Perhaps a greased steel pin would wear better?

would you please provide a website or some web information links on how to design rotating couple with metallic bearings ,circulate lubricant and so on?

Google "Glacier" "Garlock" (sp?) now known as GGB bearings

Talk to these folks; think that it will be the simplest place to start.

http://www.ggbearings.com/news-detail.asp?NewsID=358

If adding "grease grooves", try to use these at the 'neutral loading' zone in the bearing. IE: push/pull on a rail-way- place groove on top. Doesen't interrupt bearing film & gravity aids distribution.

Contrary to a previous post, i'd use a low-vis grease here. To allow motion to draw in lubricant. (only a real concern if bronze or other metallic bearings are selected)

From the field;

The SKF systems are great for trouble areas like yours. They will inject grease under pressure automatically over a period of time that you designate. This will force moisture out and relive your pitting problem.

Mike

Some bearing require Special Lubes that have no Oil bases ingredents.

Also are you postive that your shaft is true and straight ?

i am sure the shaft can undergo the loads, and has experenced many times of tests.

The previous question concerned the 'straight line' application of forces. While strong enough, a degree of flexibility can greatly reduce point loads in a bearing.

Perhaps introducing a spherical element to the connecting link would help? Else, reducing the sectional thickness on a selected axis, to promote deflection, while increasing other dimension, to prevent X-section reduction?

I have done below the bearing pressure calculations for your application:

Max Radial load on each bearing = 600 / 2 = 300 (kN)

Bearing diameter = 90 mm

Bearing length = 60 mm (assumed from sketch)

Bearing pressure = 300 x 1000 / (90 x 60) = 55.55 N / sq mm

This bearing pressure is too high for Thordon or any other composite bearing for dry running. I think you should consider only metallic bearing with good lubrication and sealing arrangement to prevent external moisture and abrasive particles, if any.

I hope this will be of help to you.

someone above directed me to turn to IGUS.

http://www.igus.com/iglide.asp

from the product catalog of IGUS, I found the type iglide Q or iglide X plain bearing maybe meet the requrement

http://www.igus.com/pdf/q.pdf

I found my rival have used some kind of non-metal material bearing in the same position. however, it is a pity that my rival rejected to tell me about the bearing.

anyone could help me to recheck the iglide Q or iglide X bearing? do the above two bearings really meet the requrement.

Calculate P x V with max load and max speed of your application and compare with the max given in manufacturer's catalogue. What is the speed or velocity of shaft rotation in your case?

I think if your load can reach 600 kN, it will be difficult to use polymer bearings. With 100 kN, it may be possible. You will still need lubrication for good performance.

We have used high molecular weight high density polyethylene (HDPE) in bearings in rock crushers with very good results. It is a non metallic self lubricating bearing material and performs well in slow moving loads. I don't know where you are but I would suggest that you contact your local DOTMAR Engineered Plastics agency for help.

Regards,

Pete.

A high and reciprocating load will tend to work the lubricant away from the region of highest contact pressure. Molybdenum Disulfide is a solid lubricant that coats the parts and takes the shear similar to (but better than) graphite.

Try using a high-viscosity grease containing Molybdenum Disulfide: example Mobilgrease CM-P (Call them for advice in best formulation).

Hello,

I would consider cylindrical roller bearings.

90x 160x 40 take static 315 kN, two 630 kN.

Or a spherical roller bearing 100x 90x 165x 52 takes static 570 kN. You would only need one and have all the flexibility you need. No more bearing failures. Greased for life. (e.g. 23120ESK.TVPB.C3, adapter sleeve H3120)

Regards

Floram

your replies frustrated me and make me nearly not choose the non metallic bearings.

on the other hand, the solution of injecting bearing plus injecting grease is difficult to me. I have not any experence on the latter ............

What is frustrating about giving you the best solution for your application?

You buy the bearing greased from the factory with seals installed on both sides and never have a problem again. Never have to add grease or any lubricant for life. No maintenance whatsoever. The spherical roller bearing flexes in all directions, also side ways. Are you sure you have zero side deflection? Two bearings side by side as shown do not allow any movement this way. If you have, all load is on one bearing only plus additional load due to side deflection.

Anyway, you got lots of helpful answers from this group. The final decision is yours, ungrateful one.

Regards

sincerely thank you. maybe my expression is not appropriate howere that is not my true thoughts.

Your load bearing areas should have a grease fitting. You would remove that fitting and install an SKF self greaser and set the delivery schedule and leave it. You can see the grease level go down on the self greaser. It is very simple.

Mike

maybe i have getten enough information. thank you all the persons. now, it is my turn to decide .........

You shuold use seals to protect the bearing of the enviromental and lubrimist

Try using Torlon 4301 bearing grade

Just in case the dimensions don't let you put there a simple roller bearing or ball bearing:SAE 64 and SAE65 bronz are mostly used for that kind of job.-

I would firmly advise against any form of roller bearing for this app. The dithering in any one spot would be likely to cause raceway erosion

The bronzes would be a v.good choice; just don't attempt to use an oil-impregnated, sintered product ("Oilite"), it will crush almost immediately, & fail.