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Types and Application of Coupling

Coupling is a device that transmits power. The coupling is mainly to connect the ends of two shafts, and then use the same speed on one shaft to drive the other shaft. In addition, the coupling allows the end movement between the two shafts, deviation or misalignment, etc. The use of couplings can reduce the impact and overload problems generated during movement, thereby prolonging the service life. Couplings are mainly used for pumps, generators, motors, etc.

Couplings are very important parts of all industrial fields. A lot of mechanical equipment needs it as a transmission function. Therefore, the factory has relatively high requirements for coupling. In order to meet the demands of various sectors, there are many different types of couplings in the market. Mainly divided into two categories which are rigid coupling and flexible coupling.

Rigid Coupling

Rigid coupling is a metal coupling that has the functions of high-temperature resistance, high drive rate, and high speed. Its structural design is simple, and it can transmit more kinetic energy than an elastic coupling. Rigid couplings are mainly used for two perfectly aligned shafts, so the angles of the connected shafts must be precisely aligned laterally and closely aligned. Due to its rigid nature, this coupling cannot accept any misaligned connections. Rigid couplings have very limited applications and are usually used in vertical drives or high-horsepower applications. It can make the drive or the motor run, and transfer the kinetic energy to the rotating parts of the equipment. The following describes some types and characteristics of rigid coupling.

  1. Clamp coupling: Clamp coupling, also known as split muff coupling, is composed of two cast iron semi-cylinders. Place the clamp coupling on both ends of the connecting shaft, make sure that the two shafts are aligned, and then use bolts to penetrate and fix it. This type of coupling cannot move on the shaft. Clamp coupling can handle huge thrust loads, and most of them are used in equipment with heavy load speeds or vertical pumps.

  2. Flange Coupling: Flange coupling is a rigid coupling, which is mainly composed of two flanges respectively connected to the end of each shaft, and then bolts are used to connect the two flanges. Most flange couplings have a male or female connector opening. When we put their ends together, they will align accordingly. The internal and external threaded joint method makes the flange can be fixed and connected more firmly. Flange couplings are usually used in pressurized piping systems or large shaft systems.

  3. Sleeve Coupling: Sleeve coupling is a rigid coupling made of cast iron. It has fewer manufacturing parts and a simple structure. Sleeve coupling is composed of the sleeve, shaft, key, and hollow cylinder. Through the sleeve and the key, the power or torque is transmitted from one shaft to another shaft. When manufacturing the sleeve, the diameter of the shaft needs to be considered so that the sleeve can fit on the shaft. Sleeve coupling is mainly applied to shafts that do not need to be aligned.

Flexible Coupling

Flexible coupling is used to connect different mechanisms with two shafts that are not aligned. These two shafts are the driving shaft and the driven shaft respectively, and the two shafts are rotated at the same time to transmit kinetic energy. Although flexible coupling can be used on misaligned shafts, we should not use it as an excuse for lack of maintenance on the shaft. Because the misalignment issue will cause excessive force to the passive load, which will lead to problems such as parts failure. Flexible couplings can be used in light industry and heavy industry respectively. Some types of flexible coupling are listed below.

  1. Gear Coupling: The gear coupling mainly uses the form of meshing between the internal gear and the external gear to transmit the torque between the two half couplings. Its structure is composed of an internal gear ring, gear shaft sleeve, end cover, and other small parts. Generally, it can be as high as 40,000 RPM. Gear couplings are compact in structure, large in carrying capacity, and suitable for handling high torque, so they are widely used in the lifting and transportation industry, petroleum, mining, and various heavy machinery industries.

  2. Jaw Coupling: The jaw coupling is composed of two metal hubs with multiple plastic arms. This type of coupling has a good outer diameter torque capacity and it can adjust the problem of misalignment as well as reduce vibration to protect the parts. Jaw couplings are mainly used to connect motors, pumps, and gearboxes. Jaw couplings can accept misaligned shafts and transfer torque and rotation between the two shafts.

  3. Diaphragm Coupling: The diaphragm coupling consists of several groups of diaphragms which are connected with two halves of the coupling by bolts. The diaphragm coupling is used on two disproportionate shafts by the elastic deformation of the diaphragm. This type of coupling transmits torque from the outer diameter of the diaphragm to the inner diameter of the diaphragm. It has the characteristics of strong corrosion resistance, long service life, no temperature influence and no need to use lubricating oil. Because diaphragm couplings are widely used in working environments with corrosive media or mechanical equipment requiring high-speed applications. Besides, the diaphragm coupling is also allowed to be used on shafts with inaccurate angles and misalignment.

The purpose of the coupling is mainly to connect two shafts together, and at the same time, it can solve the problem of misalignment of the two shafts, in order to transmit the power to the mechanical components. If you want to know more about the coupling or select a suitable coupling, please contact MecHero at 011-7000 7687 or

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