The diaphragm coupling is composed of several groups of diaphragms (stainless steel sheet) which are connected by two half diaphragm couplings staggered by bolts. Each group of diaphragms is composed of several diaphragms. The diaphragms are divided into connecting rod type and diaphragm combination type with different shapes. The diaphragm coupling relies on the elastic deformation of the diaphragm to compensate the relative displacement of the connected two shafts. The diaphragm coupling is a kind of high-performance flexible coupling with metal strong components, no lubrication, compact structure, high strength, long service life, no rotation clearance, no temperature and oil pollution, acid and alkaline corrosion resistance, which is suitable for shafting transmission under high temperature, high speed and corrosive medium environment .

The diaphragm coupling can compensate the axial, radial and angular offset of driving wheel and driven wheel due to manufacturing error, installation error, bearing deformation and temperature rise. Diaphragm coupling is a kind of flexible coupling with metal elastic elements. It relies on the diaphragm to connect the driving machine and the driven machine to transfer torque. It has the advantages of elastic vibration reduction, no noise, no lubrication and so on. It is an ideal product to replace the gear coupling and ordinary coupling.

The main features of diaphragm coupling are as follows:
Compared with the toothed coupling, the angular displacement can be doubled, the radial displacement reaction force is small, the flexibility is large, and certain axial, radial and angular displacements are allowed.

It has obvious damping effect, no noise and no wear.
It can adapt to high temperature (- 80 + 300) and harsh environment, and can work safely under shock and vibration.
High transmission efficiency, up to 99.86%. It is especially suitable for medium, high speed and high power transmission.
It has the advantages of simple structure, light weight, small volume, easy installation and disassembly; it can be installed and disassembled without moving the machine (refers to the type with middle shaft) and without lubrication.
It can transfer the speed accurately without rotation error, and can be used in precision mechanical transmission.
Correct selection of diaphragm coupling:
The diaphragm type coupling is composed of at least one diaphragm and two shaft sleeves. The diaphragm is fixed on the shaft sleeve with a pin, which is generally not loose and will not cause the recoil between the diaphragm and the shaft sleeve. Some manufacturers offer two diaphragms, others offer three diaphragms with one or two rigid parts in the middle and both sides connected to the sleeve.

This characteristic of diaphragm coupling is a bit like bellows coupling. In fact, the way of torque transmission of coupling is the same. The diaphragm itself is very thin, so when the relative displacement load is generated, it is easy to bend, so that it can withstand up to 1.5 degrees of offset, and generate lower bearing load in the servo system.

Diaphragm coupling is usually used in servo system. Diaphragm has better torque rigidity, but it is slightly worse than bellows coupling.
On the other hand, the diaphragm coupling is very delicate and easy to be damaged if it is not used or installed properly. Therefore, it is necessary to ensure that the eccentric force is within the bearing range of the normal operation of the coupling.

5. Adjust the model according to the shaft diameter:
The preliminary selection size of bearing coupling connection, i.e. shaft hole diameter D and shaft hole length L, should meet the shaft diameter requirements of driving end and driven end, otherwise, the coupling specification should be adjusted according to shaft diameter D.

When the torque and speed are the same, and the diameter of the shaft is different, the coupling model should be selected according to the large shaft diameter. The new transmission system should select seven types of shaft hole that meet the requirements of gbt3852. It is suggested to select type J1 to improve the versatility and interchangeability. The length of shaft hole should meet the requirements of I-type bearing coupling product standard.