Crankshaft%20and%20oil%20film%20journal%20bearing

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Crankshaft and oil film journal bearing

• Graham Lloyd-Smith

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Objective

• To increase overall understanding of the
  importance of the crankshaft and its specifics as
  well as the benefits of using oil film bearings.

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Crankshaft Basics

• Translates linear piston motion into rotational
• Connects to a flywheel
• Reduces torsion vibrations

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Design

• Pistons attached to crankshaft
• Fewer cylinders, simpler crankshaft design
• Linear axis
• Several journal bearings riding on replaceable
  main bearings
• Distance-axis of crank throws from crankshaft
  axis determines piston stroke measurement/engine
  displacement

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Construction

• Forged or cast from either mild steel or high
  strength steel, or machined out of single billet
  of forged steel
• Cast crankshafts-production engines, forged and
  billet crankshafts-high performance engines
• Machined to size and shape, holes, rod bearing
  journals ground and case hardened, holes threaded

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Oil Film Journal Bearings

• Bearing rotates, oil carried to working part,
  compressed
• Hydroplanes on oil
• Theoretically infinite lifespan
• More quiet and cheaper than ball bearings
• Oil pumped in through orifice, or swept into
  bearing

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References

• http//www.mustangandfords.com/howto/29178/
• http//en.wikipedia.org/wiki/Crankshaft
• http//en.wikipedia.org/wiki/Fluid_bearing
• http//www.reliabilitydirect.com/appnotes/jb.html
• http//www.efunda.com/DesignStandards/bearings/bea
  rings_fluid_film.cfm