ideas on dismantling bearings

has any one got any ideas on how I can dismantle (remove rollers) this taper bearing the rollers sit inside a recess on inner race. I would like to then be able to reassemble after cleaning.

Unless you are replacing the bearing it is difficult to remove with out damage, when replacing I normally grind it putting a flat on it till it is almost through and then split it with a cold chisel.

Bob

The old trick on motorcycle front wheel bearings was a strip of thin Celluloid sheet wrapped round the spindle and joggled about until it was under the rollers. The rollers and cage could then be slipped over the sheet and spindle. I remember that it took a bit of patience.

I don't think you can get Celluloid now (it is an explosive) but I hope you get the idea. It may not work for all bearings but it is worth remembering that the bearing was successfully assembled.

JA

Edited By JA on 13/12/2014 15:17:11

Hi Ian,

The rollers and their guide should just lift off, leaving behind the inner race. Are they just 'struck' in place with old grease?

The inner race will take a bearing puller (bought or improvised, but you shouldn't need to remove it for cleaning.

Neil

Hi Ian, the rollers are designed to be retained in the cage for life. They are not easily removed without the risk of damage to the cage, unless they and/or the cage are significantly worn, in which case the bearing would normally be replaced. My advice would be to leave them intact and wash the whole assembly with paraffin using a small paint brush and allow it to drip dry. You can blow dry it with a low pressure airline, but don't be tempted to spin the rollers with it and use all the required common sense PPE.

Regards Nick

.

Really

MichaelG.

No, you're right Michael. I blame lack of sleep for the last week... my brain was still thinking about roller thrust bearings.

Sorry Ian.

Neil

Whats that you said, 'Open mouth, engage brain' or 'Engage brain and then open mouth' Just having fun.

Clive

...and I'm still wondering how roller thrust bearings work!

Not the ones with taper rollers but the ones with parallel needle rollers arranged so the needle axis is radial.

If the needles make line contact with the thrust washer faces, then friction and slip must be involved rather than pure rolling action, this rather goes against the principle of it being a rolling bearing.

Ian P

Hi All I might be talking out of my butt but looking at that bearing it looks to be arse about face. When I serviced tractors the tapered part went on first and the roller part was put on last with a nut and cotter pin to secure.

Just my thoughts Keith.

I agree with Nick above. If you are not intending to replace the bearing do not attempt to remove it, you will almost certainly damage it if you do. Taper bearings come in a number of types and not all can be disassembled. However I would use something a more volatile than paraffin, perhaps ethyl alcohol or electrical solvent. I would then allow the bearing to dry naturally, perhaps with a gentle heat such as a central heating radiator (check with household authorities first !!!). I would definitely advise against using compressed air anywhere near an exposed bearing.

Ian. You are quite right in your assessment of the radial needle bearings involving sliding and slip. ALL bearings have this problem. The bearings you mention are only used in very low stress areas and tend to be of a small size typically they are found on the end of feed screws etc. This problem has existed since the first bearings were developed and the manufacturers have spent millions on designing and building bearings to try to mitigate it. One approach involves tapering the rollers, another is to use barrel shaped rollers with corresponding radii in the tracks. In ball bearings they use different contact angles or again radiused inner and outer tracks. The solutions and types of bearings vary according to the use the bearing is intended for. Thus the special types used in lathe mandrels (see other thread)

A look into any catalogue from a bearing manufacturer will show the differing types available. However all bearing will suffer to some extent the sliding and slip referred to. This is the reason for the finish imparted to the balls/ rollers housings etc. it also explains the use of plastic brass and metal cages. All carefully matched and machined to tight tolerance . This leads to the obvious need for lubrication and the reasons for oil or grease, again dependent on loading /duty. It must be the correct type, viscosity and quantity if you want the best from the bearing.

If foreign matter gets in or the lubrication is incorrect metal to metal contact will take place and the bearing will wear. The wear will accelerate exponentially until the bearing ultimately fails completely and seizes. Normally before complete failure the noise becomes more noticeable and if you are sensible you will investigate and replace the bearing .

Hope this helps Max.

Yep that's what I have seen in past but this has fixed outer race and the inner race is pulled at one end at the same time the mirror image at the other end of the spindle the inner race is pushed to pre-load.

Hi Ian, you mean like this;

This is the most common arrangement for pre-loaded taper roller bearings to eliminate any backlash. the idea is that it retains a constant bearing load throughout a wide temperature range. All bearings rise in temperature during use and expand, this arrangement will have the heat generated in the bearing transferred into the spindle and as this expands, the inner race moves away from the outer race and the corresponding expansion of the rollers fills up the gap keeping the load fairly constant. meanwhile the heat generated dissipates to atmosphere through the spindle and the bearing housing. All a matter of good and careful design.

Regards Nick.

Edited By Nicholas Farr on 13/12/2014 20:55:04

For a great summary of taper bearing arrangements for machine tools, courtesy of British Timken see the ME reprint HERE

Neil

Definitely not trying to tell anyone about sucking eggs here but....

If I can't get the bearing apart but need to clean it, here is a simple method that I have found to be very much more effective than brushing with a solvent.

Hold the bearing,either on its own shaft or on a suitable short stub and to lay the bearing, side down, in a flat container. Fill the container with paraffin/white spirits etc. to above the top edge of the bearing. Then, hold the bearing just clear of the bottom and spin the bearing gently with your finger under the liquid. The dirt is spun out and falls away to the bottom of the container. Repeat till it runs smoothly. Turn over occasionally and spin the other way.

It can be quite surprising how much dirt/grit can come out. Because it is spinning in the liquid there's no danger much of damage but you can feel every tiny bit of grit in there until you get it all clear. Let the cleaning liquid settle, pour off the clear liquid and keep for the next cleaning job.

Hi All

Slightly off topic but I used to be the UK agent for an American rotary trim cutter this device was used for cutting tough continuous trims leaving a process before entering an air conveying system. The rotor ran on two 1" Timken tapered roller bearings it was a common problem on rebuild to have to wash out bits of plastic from the bearings I used the method as Breva stated it worked excellently but you will be surprised what comes out and how long it takes. Incidentally the bearings were super high tolerance used to cut trims down to 12 micron. I was told that the bearing were "Bastards" taken off standard production line then measured and depending upon the run out either a one or two dot burn mark put on the inner and outer cup. I had to import them from the US and cost either £250 or £400 plus per bearing depending upon the tolerance.

Peter

The bearings in a car cv joint are individually mated with each socket at the factory to maximise a tough working life

Chances are that the same system is used with those pricey high load bearings in machine tools so dont let the bearing fall to bits

Lidl Aldi etc sell a sonic bath cleaner for 20 quid btw. May be worth looking out for one

Edited By Ady1 on 14/12/2014 12:01:27