Shaft couplings 3 rigid flange coupling

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Shaft Couplings
Rigid Flange Coupling Design

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

2. RIGID FLANGE COUPLING Construction 2 Flanges 4 or 6 bolts Spigot & Recess

3. PROTECTIVE TYPE RIGID COUPLING Protects operator against injuries Advantages High torque transmitting capacity Easy to assemble & dismantle Simple in construction Easy to design & manufacture

4. Disadvantages Cannot tolerate misalignment between two shafts Used only where the motion is free from shocks & vibrations Requires more radial space

5. Proportions of Rigid Coupling

6. No. of bolts

7. Analysis of Rigid Coupling

8. Analysis of Rigid Coupling

9. Design Procedure for Rigid Flange Coupling

10. Problem 1 A rigid coupling is used to transmit 20 kW power at 720 rpm. There are four bolts and the pitch circle diameter of the bolts is 125 mm. The bolts are made of steel 45C8 ( S yt = 380 N/mm 2 ) and the factor of safety is 3. Determine the diameter of the bolts. Assume that the bolts are finger tight in reamed and ground holes.

11. Problem 2 A rigid coupling is used to transmit 50 kW power at 300 rpm. There are six bolts. The outer diameter of the flanges is 200 mm, while the recess diameter is 150 mm. The coefficient of friction between the flanges is 0.15. The bolts are made of steel 45C8 ( S yt = 380 N/mm 2 ) and the factor of safety is 3. Determine the diameter of the bolts. Assume that the bolts are fitted in large clearance holes.

12. Problem 3 It is required to design a rigid type of flange coupling to connect two shafts. The input shaft transmits 37.5 kW power at 180 rpm to the output shaft through the coupling. The service factor for the application is 1.5, i.e., the design torque is 1.5 times of the rated torque. Select suitable materials for various parts of the coupling, design the coupling and specify the dimensions of its components.

13. References: Machine Design - V.Bandari . Machine Design – R.S. Khurmi Design Data hand Book - S MD Jalaludin .