Installation process of coupling

For the coupling and shaft with the corresponding clearance can be cleaned up after the surface with lubrication grease directly installed. For transition fit and interference is not very large fit, or have special requirements (such as protection has installed precision other parts) can be used by pressing method, but need to press into the equipment. Thermal assembly of coupling is often used in the installation of heavy equipment such as large motors, compressors and rolling mills, because the coupling and shaft in such equipment are usually connected by interference fit. There are several assembly methods of interference coupling, such as pressing assembly, low temperature cold assembly and hot sleeve assembly. The cold shrinkage assembly method generally uses liquid nitrogen as a cold source and requires a required adiabatic container, so it can only be used when conditions are available.
The essential principle of hot sleeve assembly is to heat the inclusion part (hole), make its diameter expand a fit interference value, and then load the inclusion part (shaft), after cooling, the machine will reach the required bonding strength. In fact, the heating expansion value must be larger than the fit interference value, so as to ensure the smooth installation and avoid the serious accident of shaft and hole stuck due to the cooling contraction of the containment parts in the installation process. At the same time, in order to ensure a larger meshing force - bonding strength, the bonding surface of the hot sleeve assembly should be processed, but not too smooth, because the necessary surface roughness (generally Ra3.2) is not flattened by axial movement. After cooling, the combination strength of internal and external parts will be larger, and the torsion can be transmitted is also larger.
Selection of heating method
The method of heating the containment element to the required temperature shall be selected according to site conditions, the size, quantity and requirements of the heated element. General heating methods are: solid fuel heating, hot dip heating, oxygen-acetylene flame heating, blowtorch heating, electric heating, etc. If conditions permit, it can be heated in special furnace (such as flame heating furnace and salt bath furnace, resistance furnace and other electric heating furnace). When the site conditions do not allow, can build a simple stove, and use wood, coke and other solid fuel, heating. If conditions permit, gas and liquid fuel can also be sprayed. Immersion heating is usually only used for small size coupling (inner diameter below 100mm), the method is simple, uniform heating. When the oxygen-acetylene flame heating method is used to heat small parts or parts of larger parts, the method is simple, but it requires more skilled technology to prevent overheating and burning parts. For large couplings, a plurality of oxygen-acetylene flame heating and blowtorch heating combined use, the effect is very good. Although the electric heating method is a better heating method, but because of the need for special equipment, limited its use in the installation site site, but the electric induction heating method, or can be considered. The electric induction heating method used in the installation site for large and medium-sized couplings is to pass the working frequency (50Hz), low voltage and high current in the induction coil. Under the same condition and material, the current frequency f is inversely proportional to the current penetration depth δ. Now we want to have a large delta, so we do not use medium frequency (500 ~ 10000Hz) and high frequency (105 ~ 106Hz), but use the operating frequency (50Hz). Low voltage and high current can enhance the loss of alternating eddy current and hysteresis and increase heat. The voltage usually used is 380V and 220V.
In practice, common accidents are:
1. In order to prevent this kind of accident, in addition to the calibration of the axis, the position of the coupling hole and shaft, the position of the collision block is correct, but also pay attention to the impact point position to choose the first and second to be light, to enter a distance (about 1/3), before hard hit.
2. Other accidents may include: bump block pulley backing due to unsecured position, hoist chain sliding down, fuel shortage, fire alarm, etc. All should be noted in advance and carefully checked during tool preparation and operation training.
3. When precision components such as bearings and mechanical seals are installed in advance on the spindle, it is forbidden to strike and impact the coupling forcibly to prevent damage or damage to precision components.