What are Different Types of Shaft Coupling?

Shaft coupling refers to a device that connects two shafts or shafts and rotating parts, rotates together in the process of transmitting motion and power, and does not disengage under normal circumstances. Sometimes it is also used as a safety device to prevent the connected parts from being subjected to excessive load, and plays the role of overload protection. The shaft coupling is the interface for the high-precision connection between the shaft and the shaft.

Shaft couplings are also called shaft couplings. A mechanical component used to firmly connect the driving shaft and the driven shaft in different mechanisms to rotate together and transmit motion and torque. Sometimes it is also used to connect shafts and other parts (such as gears, pulleys, etc.). It is often composed of two halves, which are respectively connected by keys or tight fittings, and are fastened at the ends of the two shafts, and then the two halves are connected in some way. The shaft coupling can also compensate for the offset (including axial offset, radial offset, angular offset or comprehensive offset) between the two shafts due to inaccurate manufacturing and installation, deformation during operation or thermal expansion, etc. and shock mitigation and vibration absorption.

Most of the commonly used shaft couplings have been standardized or standardized. Generally, it is only necessary to correctly select the type of shaft coupling and determine the type and size of the shaft coupling. When necessary, the load capacity can be checked and calculated for its vulnerable weak links; when the rotation speed is high, the centrifugal force of the outer edge and the deformation of the elastic element should be checked, and the balance check should be carried out.

The role of the shaft coupling

Shaft couplings are used to connect shafts in different mechanisms, mainly through rotation, so as to transmit torque. Under the action of high-speed power, the shaft coupling has the functions of buffering and shock absorption, and the shaft coupling has a better service life and work efficiency guarantee.

The function of the shaft coupling: a device that connects two shafts or a shaft and a rotating member, and rotates together during the transmission of motion and power, and does not disengage under normal circumstances. Sometimes it is also used as a safety device to prevent the connected parts from being subjected to excessive load, and plays the role of overload protection.

The shaft coupling is installed between the driving side and the passive side of the power transmission, and plays the role of transmitting rotational torque, compensating for installation deviation between shafts, absorbing equipment vibration and buffering load impact. One of the functions of the shaft coupling is to absorb and compensate for shaft-to-shaft misalignment through its own deformation. The greater the flexibility, the stronger the ability to absorb deviation; the smaller the flexibility, the weaker the ability to absorb deviation. Generally speaking, the deviation between the shaft and the shaft is divided into the following three aspects: the connection between the shaft coupling and the peripheral equipment is realized by inserting the shaft of the equipment into the shaft hole of the shaft coupling.

1. The function of the shaft coupling is to connect the two shafts (the driving shaft and the driven shaft) in different mechanisms to make them rotate together and transmit torque. Some shaft couplings also have buffering, damping and improving the dynamic performance of the shaft system. effect.
2. To eliminate the inertia of radial force, use the shaft coupling between the motor shaft and the load to weaken the starting force when the motor starts.
3. Power transmission, transmitting power and torque (improving the working performance of the transmission system).
4. Different degrees of vibration reduction and buffering.
5. Disconnect for protection when the load is too large.
6. Conducive to maintenance.
7. Change the transmission direction.
8. Concentricity correction (different degrees of axial, radial and angular compensation performance).

Types of shaft shaft coupling

Flexible shaft coupling

Among the shaft couplings, some are flexible and deformable. When connecting two axes of rotation, some misalignment of the two axes of rotation is allowed, ie a dynamically deformable shaft coupling. The use of flexible shaft couplings reduces alignment accuracy requirements, facilitates testing, and provides good shock absorption under unstable rotational speeds. But it has a disadvantage, because its material is rubber, nylon, etc., so it has low strength, short life, small bearing capacity, is not resistant to high temperature and low temperature, and is only suitable for low temperature occasions.

Plum shaft coupling

Plum shaft coupling is a widely used shaft coupling, also known as claw shaft coupling, which consists of two metal claw discs and an elastic body. The two metal claw discs are usually 45 steel, but aluminum alloys are also useful where load sensitivity is required. Its elastomer is usually composed of engineering plastics or rubber. The life of the elastomer is the life of the shaft coupling. The life of the elastomer is 10 years. Since elastomers have the function of buffering and reducing vibrations, they are widely used in the case of strong vibrations. The ultimate temperature of the elastomer determines the operating temperature of the shaft coupling, usually -35 to +80 degrees.

Elastic column shaft coupling

An elastic column shaft coupling is a pin made of some non-metallic elastic material that is placed in the flange holes of the shaft coupling halves. Via this pin, two half-couplers can be connected. The structure of the shaft coupling is simple and easy to manufacture. It is convenient to install, remove and replace the elastic element without moving the two shaft couplings.

Spring shaft coupling

Spring-loaded shaft couplings transmit motion by welding or connecting corrugated thin-walled tubing directly to the shaft coupling halves. The spring type shaft coupling has simple structure, small volume, convenient processing and installation, and high transmission precision. They are mainly used in low-power precision machinery and control mechanisms that require compact structure and high transmission accuracy.

Universal joint shaft coupling

The universal joint uses the characteristics of its mechanism so that the two shafts are not on the same axis and there is an angle between the shafts. It enables continuous rotation of both axes and reliably transmits torque and motion. The biggest feature of universal joint shaft coupling is that its structure has large angle compensation ability and compact structure, but its transmission efficiency is not very good compared with other shaft couplings. The angle between the two shafts of the universal joint shaft coupling of different structural types is different, usually between 5-45.

Rigid shaft coupling

Rigid shaft coupling, as the name suggests, a rigid shaft coupling is actually a torsionally rigid shaft coupling. Even under load, there is no cornering clearance. Rigid shaft couplings are rigid to transmit torque even in the presence of load-producing deflections. Rigid shaft couplings need to be used to connect two shafts in strict alignment without relative misalignment, so they are less used in motor test systems. Of course, if the relative displacement can be successfully controlled (with high enough alignment accuracy), rigid shaft coupling can also play an excellent role in the application. In particular, the small size of the rigid shaft coupling has the advantages of light weight, ultra-low inertia and high sensitivity. In practical applications, rigid shaft couplings have the advantages of being maintenance-free, super oil-resistant and corrosion-resistant.

Membrane shaft coupling

Several sets of diaphragms (stainless steel plates) are interleaved with the two shaft coupling halves by means of bolts. Each set of diaphragms consists of multiple parts, which are divided into connecting rods and different shapes of the entire diaphragm. The membrane shaft coupling compensates for the relative displacement of the two axes by elastic deformation of the diaphragm. It is a high performance elastic shaft coupling with strong metal elements. It does not require lubrication, has a compact structure, high strength, long service life, no rotating gap, and is not affected by temperature and oil contamination. It is resistant to acid, alkali and corrosion and is suitable for high performance. The shafting drive has working conditions of temperature, high speed and corrosive medium. In terms of structural features, it has an insurance link. When the actual load exceeds the predetermined load, the diaphragm will break, cutting off motion and power transmission, thus protecting the rest of the machine from damage and acting as a safety protection.