Mechanical Coupling is used to connect driver and driven shafts and transfer torque between them. Coupling is a very important element in connecting two shafts because it reduces the impact of misalignment between shafts.
For example, Shaft from the engine and rear axle and connected using a universal joint and universal joint is a type of coupling. In this article we will cover various types of coupling and their applications.
Applications of Mechanical Coupling
Why are mechanical couplings used? Can’t we weld two shafts or use a gear box instead? Answer to this question is “NO”. Couplings have their own advantages. Gears or Welded joints can not replace couplings. Mechanical Coupling can have following applications:
1. Transmits Power
Mechanical coupling is used to connect the driver and driven shaft. In this way they work as a joint between the driver and driven shaft to transfer power.
2. Protection Against Overloading
Overload safety mechanical coupling limits the transfer of torque from one shaft to another. In this way they protect the driver and driven system from jamming and overloading.
3. Absorbs Misalignment
Nothing is perfect in this world. Parts are manufactured with engineering tolerances. Expecting perfectly aligned shafts in the real world is a bigger challenge. Therefore welding input and output shafts is not a good practice if shafts are misaligned. Couplings are used to absorb misalignment between connected shafts.
4. Absorb Shock and Vibrations
Reduction in the shock and vibrations acting on engine or motor increases engine life. Since coupling joints are not rigid by design. Therefore it is a good practice to use coupling to reduce the transfer of vibrations from input shaft to output and vice-versa.
Types of Coupling
Following types of couplings are available in market according to their construction and applications:
- Jaw Couplings
- Sleeve Coupling
- Flange Couplings
- Gear Couplings
- Magnetic Couplings
- Hooke’s Joint
Let’s discuss each of the above type of coupling in detail.
1. Jaw Coupling
Jaw Coupling is a type of mechanical coupling that utilizes flex material such as Hytrel, NBR, Polyurethane to transmit torque, align shaft and damp vibrations between connected shafts. They are used to transmit a small amount of torque between connected shafts.
2. Sleeve Coupling
Sleeve coupling is a thick hollow cylinder with a provision to connect the driver and driven shaft. They are used to transmit small torque and can adjust small misalignment between shafts as well.
3. Flange Coupling
Flange coupling is similar to sleeve coupling but it has a flange around the sleeve.
4. Gear Coupling
Gear coupling consists of two flanges/sleeves and two Hubs. Both Hubs have crowned external teeth. Whereas both sleeves have internal teeth and are bolted together. 1:1 gear ratio is maintained, to ensure equal amount of torque transfer and speed. Gear coupling is used to transfer very high torque and require periodic lubrication.
5. Magnetic Coupling
Magnetic Coupling utilizes magnetic fields to transfer motion or torque from one shaft to another without any physical contact between them. This type of couplings are generally used where hermetic sealing is required such as centrifugal pumps, electromagnetic clutch etc.
6. Universal Coupling / Hooke's Joint
Hooke’s joints are used to connect rigid non-aligned shafts to transmit rotary motion. They are used to transmit high torque and can accommodate high misalignment between rigid shafts.
To sum up, Mechanical Couplings are used to join two rotating shaft. It has the advantage of protection against overloading, absorb misalignment and shock.
We will keep adding more information on various types of couplings and their applications. Please add your suggestions, comments or questions on types of coupling and their applications in the comment box. We suggest you also read this article on various types of bearings.