Introduction to the main characteristics of diaphragm coupling:

1. It has strong ability to compensate for misalignment of two axes. Compared with gear couplings, the angular displacement 

can be doubled. The reaction force during radial displacement is small and the flexibility is large. It allows certain axial, radial 

and angular displacements. Displacement.

2. Adapt to working in high temperatures (-80+300) and harsh environments, and can move safely under conditions of shock 

and vibration.

3. It has obvious shock absorption effect, no noise and no wear.

4. High transmission efficiency, up to 99.86%. Especially suitable for medium and high speed high power transmission.

5. Simple structure, light weight, small size, and easy to assemble and disassemble. It can be assembled and disassembled 

without moving the machine (referring to the type with intermediate shaft), and no lubrication is required.

6. It can accurately transmit the speed and operate without slip. It can be used for the transmission of precision machinery.

Various problems will occur during the installation process of diaphragm couplings. How should we judge if we encounter them 

during installation?

The following are the issues that should be paid attention to before installing the diaphragm coupling:

(1) Dynamic balancing.

As the machine speed increases, there is an eccentricity between the inertia spindle of any rotating component and the rotation 

axis. The unbalanced inertia moment it generates during operation will definitely cause vibration of the transmission shaft system, 

leading to machine component failure. If there are parts in the elastic coupling that can move relative to each other, it is more likely

 to cause imbalance. Therefore, the diaphragm coupling itself in many high-speed equipment has been dynamically balanced, and 

the half coupling is installed on the shaft and then dynamically balanced to ensure the dynamic balance of the system.

For the unit, when maintenance and technical personnel pay more attention to it, the installation of the coupling will generally be 

carried out according to the design requirements. But for high-speed pumps, it is easy for maintenance personnel to ignore the 

balance problem of the wheel. Compared with the mass of the high-speed pump rotor, the counterwheel accounts for a large 

proportion, and it is easy to produce a large unbalanced force at high speeds. The input shaft of a high-speed pump is subject to 

relatively complex forces, and unbalanced forces can easily interfere with the normal forces of the bearings and gears, causing 

equipment abnormalities. Therefore, it is recommended that when installing the diaphragm coupling, the installation should be 

strictly in accordance with the design requirements to ensure the normal operation of the equipment.

(2) Deformation of half coupling.

Improper use or installation may cause deformation of the half coupling, which will cause the diaphragm to produce an abnormal 

bending stress when installing the tightening bolts. Different from the aforementioned additional stress caused by axial deviation, 

this bending stress is asymmetric to the diaphragm and occurs at the deformation part. The size of the bending stress and the degree 

of deformation, the thickness of the diaphragm, the number of bolts, the radius of the bolts, etc. related factors. Deformation of the 

half coupling can easily cause vibration, noise, premature cracking of the diaphragm, etc.

During maintenance, there are too few inspections for the deformation of the half coupling. According to relevant manufacturer 

information, generally the runout of the outer circle and end face of a diaphragm half coupling is ≤0.05mm, and the limit runout of a 

diameter >250mm or a tapered hole fit is ≤0.08mm. Therefore, it is recommended to determine the maintenance procedures and 

check the deformation of the half coupling during installation to ensure that the equipment operates normally.

(3) Installation

The axis of the diaphragm coupling is crooked and the coupling cannot be bumped in: In order to prevent this type of accident, in 

addition to being correct in calibrating the axis, the position of the coupling hole and the shaft, and the position of the collision block, 

attention must also be paid to , The location of the impact point should be selected well, the first and second blows should be light, 

and only after a certain distance (about 1/3) has been reached, can the forceful blow be used.

(4) Others

Some other minor issues should also be noted: the coupling mounting bolts cannot be replaced with ordinary bolts. The mounting 

bolts should be tightened to the required torque. The bolt penetration direction cannot be reversed. If the diaphragm has pre-stretching 

or pre-compression requirements, be sure to determine the starting position between the prime mover and the equipment, and then add 

or subtract the adjusting gasket on the coupling as required. The coupling and the shaft are matched with a tapered hole. Be sure to check 

the contact rate of the inner hole.