MECH 3440-Notes 3 - Couplings

  1. Couplings
    • a device used to connect two shafts together at their ends for the purpose of transmitting power
    • primary purpose of couplings is to join two pieces of rotating equipment while permitting some degree of misalignment or end movement or both
  2. Considerations when choosing a coupling
    • 1. temperature
    • 2. torque and power rating
    • 3. RPM4. S.F.; type of load (shock, fluctuating, etc.)
    • 5. misalignment issues
    • 6. purchase, installation and maintenance costs
    • 1. Angular misalignment
    • 2. Offset misalignment
  4. 8 types of couplings
    • Clamp or sleeve coupling
    • Modified clamp coupling
    • Spider or jaw and slider coupling
    • Chain coupling
    • Grid-flex coupling
    • Gear coupling
    • Para-flex or elastomeric coupling
    • Fluid coupling
  5. sleeve coupling
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    • basic type of coupling
    • consists of a pipe whose bore is finished to the required tolerance based on the shaft size
    • a keyway in made in the bore in order to transmit the torque by means of the key
    • Two threaded holes are provided in order to lock the coupling in position
    • ADV: Rigid coupling for transmitting high torques at high speeds
  6. clamp coupling
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    • sleeve used in this type is split from one side
    • shafts are entered and keyed to this sleeve and then split sides are screwed together
  7. Modified clamp coupling
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    • modified based on fit
  8. Spider or jaw and slider coupling
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    • Both half of the couplings have three shaped lugs
    • When the coupling halves are fitted together the lugs on one half fit inside the spaces
    • between the lugs on the other side
    • When the coupling halves are fitted together the lugs on one half fit inside the spaces
    • between the lugs on the other side
    • The drive is by the lugs transmitting the torque
    • through the rubber spider spacer
    • DISADV: only used for low power drives
  9. Chain coupling
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    • Chain Couplings transmit torque through two hubs with hardened sprocket teeth and a double width roller chain
    • ADV: High torque capacity and least expensive coupling in the medium torque range
  10. Grid-flex coupling or Grid Lign
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    • use two slotted hubs with a steel grid running between them to transmit torque
    • The coupling flexes by allowing the grid to slide along the slots in the hubs
    • ADV: Torsionally flexible and resilient - vibration reduction up to 30%
  11. Gear coupling
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    • gear coupling is a mechanical device for transmitting torque between two shafts that are not collinear
    • consists of a flexible joint fixed to each shaft
    • two joints are connected by a third shaft, called the spindle
    • ADV: coupling is capable of high speeds and high power capacity = high torque
    • DISADV: it requires lubrication
  12. Para-flex or elastomeric coupling
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    • employ a molded, non-lubricated elastomeric
    • flexing member loaded in shear
    • ADV: Finished Bore Flanges offer extra bore capacity that allows smaller coupling selections
    • ADV: designed to accomodate concurrent angular, parallel, and axial misalignment and ensure fast, easy installation
  13. Fluid coupling
    - When the motor is rotated, the fluid is picked up in the vanes of the impeller and thrown outwards, across the gap, towards the vanes of the runner. As a result of the fluid kinetic energy, the runner begins to rotate and drive the driven machine
Card Set
MECH 3440-Notes 3 - Couplings