JNTUK 2-2 semester DMM-1 5.SHAFT COUPLINGS MUFF COUPLING VIDEO LINK: https://www.youtube.com/cards?v=SB3bTGaT5vo&nrts=1&nv=1

1. SHAFT COUPLINGS
D. Narendra Varma,
Assistant Professor,
Mechanical Engineering Dept.,
Miracle Educational society Group of Institutions.

2. Contents
Rigid Couplings -
• Muff Coupling
• Split Muff Coupling
• Flange Couplings
Flexible Couplings –
• Flange coupling (modified)

3. Couplings
• A coupling can be defined as a mechanical
device that permanently joins two rotating
shafts to each other.
Example
• Output shaft of engine to Input shaft of hydraulic pump
• Electric motor to Gearbox of Machine tool
• Electric motor to compressor

4. Types
Oldham Coupling Hooke’s or Universal coupling

5. Rigid & Flexible couplings
• Rigid coupling cannot tolerate
misalignment between the
axes.
• Used where motion is free
from shocks & vibrations.
• Simple and inexpensive.
• Flexible coupling can tolerate
0.5% angular and 5mm axial
misalignment with the help of
bushes or discs.
• Can absorb shocks and
vibrations.
• Costlier due to additional
parts.

6. Requirements of a good coupling
• Capable of transmitting torque
• Should keep two shafts in alignment
• Easy to assemble and disassemble for repairs
and alterations
• Sharp edges and failure of revolving bolt heads
and other parts should be covered.

7. Muff coupling
• Sleeve or box coupling
• Simple
• No projecting parts
• Compact in construction
• Cheaper
Disadvantages
• Difficult to Assemble or
dismantle
• Requires accurate alignment
• Requires more axial space
• Cannot tolerate misalignment

8. Design of Muff coupling

9. Design of Muff coupling
• Design a muff coupling to connect two steel
shafts transmitting 25 kW power at 360 rpm.
The shafts and key are made of plain carbon
steel 30C8 (Syt = Syc = 400N/mm2). The sleeve is
made of grey cast iron FG 200(Sut= 200
N/mm2). The factor of safety for the shafts and
key is 4. For the sleeve, the factor of safety is 6
based on ultimate strength.

14. References:
1. Machine Design - V.Bandari .
2. Machine Design – R.S. Khurmi
3. Design Data hand Book - S MD Jalaludin.