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About Bearing basics

  1. Jun 7, 2013 #1
    Hi all,
    I have recently started my machine design course in engineering and I am finding the topic of bearings difficult to follow.
    I understand the need for bearing.What I cannot understand is what axial,radial and tangential loads will try to do with the bearing (especially the tangential load).

    Can anyone provide some references to illustrate the loads and their effect on bearings?

    Sorry if something is confusing.I just want some graphical description for bearings.
     
  2. jcsd
  3. Jun 8, 2013 #2
  4. Jun 8, 2013 #3

    462chevelle

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    what kind of bearing? crankshaft, tapered, roller, needle, ball???
     
  5. Jun 9, 2013 #4
    First of all thanks for the replies.

    I just wanted to understand a simple system with say deep groove ball bearings.I went through some references and now i think i have some of my questions answered.

    What I don't understand still is how do radial and thrust bearings differ construction wise.How is a bearing specifically constructed to take more axial or radial load.

    Thanks in advance
     
  6. Jun 9, 2013 #5

    462chevelle

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    a thrust bearing is designed with wide grooves in it and a radial bearing usually only has a groove in the block side of the bearing except an olds 455, that I know of. the groove towards the block is to help oil flow across the bearing rather than just having a hole in it. where as on a rod bearing the hole is in the crankshaft and the bearing is spinning on the crank that such will oil the whole bearing. but on a main the groove helps spread the oil out. and as far as bearings on a crankshaft go the clearance is more important to keep the oil film as the ''bearing material'' because if you had any metal to metal contact. you have catastrophic failure in this instance. and if you have for instance an axle bearing that doesn't have a c clip that carries a side load. it will be tapered to help it carry a load. where as if you use a c clip you don't need the taper because the load is to the c clip and carrier pin. what application are you talking about using these bearings in. and maybe I could give you less automotive specific advice
     
  7. Jun 12, 2013 #6
    Here's a cross-section of a pure radial-load bearing.

    %D0%B0%20%D0%BD%D0%B0%D1%80%D1%83%D0%B6%D0%BD%D0%BE%D0%BC%20%D0%BA%D0%BE%D0%BB%D1%8C%D1%86%D0%B5.png

    Imagine that there's a shaft going through it's center, and imagine a radial load on the top race. The load would go straight through the roller and into the shaft...and thus it would be well supported.

    Radial.png

    Now imagine trying to ask this bearing to withstand a thrust load on its top race. there's nothing supporting the load. In fact, the bearing would simply fall apart.

    Thrust.png


    You have to rotate the rollers 90 degrees to turn this into a thrust bearing. Of course, then it would take no radial load. You can also rotate the rollers maybe 45 degrees, so it can take a bit of both loads...

    [Broken]

    s-c-h-s-thr.jpg

    If you examine other types of bearings...ball, fluid, whatever, you will see from their layout that they are simply weaker for one type of load than the other, or in some (most?) cases will simply fall apart if asked to take a load they are not designed for.
     
    Last edited by a moderator: May 6, 2017
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