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Force Req'd to remove bearing? (press fit)

Force Req'd to remove bearing? (press fit)

Force Req'd to remove bearing? (press fit)

(OP)
Anyone have a shortcut to estimate force required to pull press fits apart? We've got a maintenance guy looking for info so they can buy a new puller (I said just get it as big as you can) Bearings are heated for shrink fit.
Thanks!

RE: Force Req'd to remove bearing? (press fit)

Good advice since you do not give an
information as to the sizes of shaft
or bore.  The bearing manufacturer
certainly specified some value or
recommended some specific tool.

RE: Force Req'd to remove bearing? (press fit)

(OP)
Shaft diameters run from around 40mm to 150mm.
Good idea - I'll contact bearing sources and ask....  but the latest group of Tech Support Engineers at most bearing companies just seem to look in the catalog.  As soon as the dept Machinist Handbook wanders back home, I can check there too.  

RE: Force Req'd to remove bearing? (press fit)

1.Need the brg no and make if you would like a quantified value in answer and  suggested design for the puller unit..
OR
2.If the manufacturer and/or local supplier is easily accessible to you right away, get the dets from the horse's mouth straightaway.

a) Heat the brg with local open flame and/or induction coil heaters. Will ease the fit atleast to the extent the puller can pull off with ease - expect ~1.0 to 1.25 times the force
initially utilised to final-seat the brg, had it been a shrink fit on the tolerances.

b)A 3-Jaw std design puller w/ a hyraulic pusher cyliner arrgt capable of 3.0T -5.0T hydr load should work.

c) Personally have also used a simple plate puller sized to seat 'behind'the brg on its seated posn and use hydr force as above toease it out.

d) NO HAMMERING pls- if you do, forget any reuse of the brg.

RE: Force Req'd to remove bearing? (press fit)

Talk to SKF, Timken, FAG or relevant bearing supplier. Shrink fits used with bearings will affect the bearing clearances. They are normally specified by bearing manufacturers and the manufacturers should be able to provide sensible info re removal.If you use an open flame to heat the bearing be prepare to replace the bearing.  

RE: Force Req'd to remove bearing? (press fit)

Machinery Handbook has a good section for calculating force required.  Look in index under shrink fits.

Jesus is The TRUTH

RE: Force Req'd to remove bearing? (press fit)

10 tons of force per inch of shaft. This is the rule of thumb Power Team (OTC) uses for recommendations.

RE: Force Req'd to remove bearing? (press fit)

If you want to be theoretical, you could calculate the total contact force from the shrink fit [thick-walled cylinder analysis]& multiply it by a friction factor [& multiply that times a fudge factor for rusted on & stuck ]

R.G.Budynas, "Advanced Strength & Applied Stress Analysis" (New York: McGraw-Hill)1977 has a good section on shrink/press fits under Thick-walled cylinders [pg. 143]

RE: Force Req'd to remove bearing? (press fit)

Buy yourself a good upright hydraulic press. It has a multitude of uses. For work in the field, get a hydraulic power unit (hand pump) and make up your own backing plates and tie rods as required. A couple of different cylinder sizes will cover all. If your pulling a bearing, replace it. Your hot wrench is a big tool for bearing pulling, especially if the locktite bottle has been out.

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