On the basis of considering the comprehensive factors, the selection procedure of coupling is as follows:
1. Select standard coupling.
China has developed a considerable number of standard couplings of different varieties, different structural types and specifications, which can basically meet different torque, speed and working conditions. Only when the existing standard coupling and patent coupling can not meet the design requirements, we need to design our own coupling.
2. Select the type and type of coupling.
Understand the comprehensive function of coupling (especially flexible coupling) in the transmission system, and select the type and type of coupling from the overall design of the transmission system. According to the prime mover category, working load category, working speed, transmission accuracy, two axis offset, temperature, humidity, working environment and other comprehensive factors. Select the structure type of coupling according to the needs of matching host. When the coupling is used together with the brake, the coupling with brake wheel or brake disc should be selected; when overload protection is needed, the safety coupling should be selected. Flange type should be selected when connecting with flange; for long distance transmission, intermediate shaft type or intermediate sleeve type should be selected when the axial size of connection is large.
3. Calculation of coupling torque
The power of the power machine in the transmission system should be greater than that of the workpiece machine. According to the power and speed of the power machine, the theoretical torque T of the high-speed end connected with the power machine can be calculated; according to the working condition coefficient K and other relevant coefficients, the calculated torque T of the coupling can be calculated.
4. Preliminary selection of coupling model.
According to the calculated torque TC, the similar nominal torque TN can be selected from the standard series, and TN ≥ TC should be met. The model (specification) of the coupling is preliminarily selected. It can be found from the standard that the allowable speed [n], the maximum radial dimension D and the axial dimension l0 of the coupling should meet the requirements of the coupling speed n ≤ [n].
5. Adjust the model according to the shaft diameter.
The preliminarily selected size of the coupling, i.e. the diameter of the shaft hole D and the length of the shaft hole L, should meet the requirements of the shaft diameter at the driving end and the driven end. Otherwise, the specification of the coupling should be adjusted according to the shaft diameter D. It is a common phenomenon that the shaft diameter at the driving end and the driven end is different. When the torque and speed are the same, and the shaft diameter of driving end and driven end is different, the coupling model should be selected according to the larger shaft diameter.
In the newly designed transmission system, seven types of shaft holes should be selected according to GB / t3852, and type J1 shaft hole is recommended to improve the versatility and interchangeability. The length of shaft hole shall meet the requirements of coupling product standard.
6. Select the connection type.
The selection of coupling connection type depends on the connection type between driving end and driven end and shaft. Generally use key connection, is a unified key connection type and code. In CGB / t3852, there are seven key slot types, four keyless connections, and type a key (flat key single key slot) is widely used.
7. Select the type, type and specification (model) of coupling
According to the load type, speed, working environment and other comprehensive factors of power machine and coupling, the type of coupling is selected; according to the matching and connection of coupling, the type of coupling is selected; according to the rated torque, shaft hole diameter and shaft hole length, the specification (model) is selected. In order to ensure the strength of shaft and key, after selecting the type (specification) of coupling, the strength of shaft and key should be checked and calculated to finally determine the type of coupling.
In shafting transmission, there are different degrees of relative deviation between the two shafts, so flexible coupling should be selected; when the working load in shafting transmission produces impact and vibration, elastic coupling should be selected. Considering the effect of vibration reduction, buffering and economy, the elastic coupling with non-metallic elastic elements should be selected.