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Coupling selection
Dec 10, 2018

1. Select the scale coupling. When choosing a coupling, the design staff should first choose among the couplings that have been developed to the national scale, the mechanical industry scale, and the national patent. Only when the existing scale couplings and patent couplings are not sufficient for design needs. You need to design your own coupling.


2, choose the type and type of coupling

Understand the comprehensive function of the coupling (especially the flexible coupling) in the transmission system, and select the type and type of the coupling from the overall design of the transmission system. The types of couplings are selected according to the original factors, the type of work load, the working speed, the transmission accuracy, the two-axis offset condition, the temperature, the humidity, the working environment and the like. According to the needs of the supporting main machine, choose the structure type of the coupling. When the coupling and the brake are used together, the coupling with the brake wheel or brake disc type should be selected. When the overload protection is needed, the safety coupling should be selected. When connecting with the flange, the flange type should be selected; for long-distance transmission, when the axial dimension of the connection is large, the intermediate shaft type or the intermediate sleeve type should be selected.


3. Coupling torque calculation

The power of the power unit in the transmission system should be greater than the power required by the workpiece machine. According to the power and speed of the power machine, the high-speed theoretical short torque T connected with the power machine can be calculated; according to the working condition coefficient K and other relevant coefficients, the calculated torque Tc of the coupling can be calculated. The coupling T is inversely proportional to n, so the low speed end T is larger than the high speed end T.


4, primary coupling model

According to the calculated torque Tc, the approximate nominal torque Tn can be selected from the scale series, and Tn≥Tc should be satisfied during the selection. Initially select the coupling model (specification), from the scale can be found the allowable speed of the coupling [n] and the maximum radial dimension D, axial dimension L0, to meet the coupling speed n ≤ [n] .


5, according to the shaft diameter adjustment model

The initially selected coupling coupling dimensions, ie the shaft hole diameter d and the shaft hole length L, shall comply with the requirements of the main and driven end shaft diameters, otherwise the coupling specifications shall be adjusted according to the shaft diameter d. The main shaft and the driven end shaft diameter are different. It is a common phenomenon. When the torque and speed are the same, and the main and driven end shaft diameters are different, the coupling type should be selected according to the large shaft diameter. In the newly designed transmission system, the seven types of shaft holes specified in GB/T3852 should be selected. It is recommended to use the J1 type shaft hole type for improved versatility and interchangeability. The shaft hole length is based on the coupling product scale. Delimited.


6, choose the connection type

The choice of the coupling type depends on the connection type of the main and the driven end on the shaft. Generally, the key connection is used, and the same key connection type and code number are defined. In the GB/T3852, seven keyway types are defined, and four types of keys are not available. For the connection, the A type is used more.


7. Select the coupling type, type and specification (model)

According to the comprehensive factors such as the load type, speed and working environment of the power machine and the coupling, the coupling type is selected; the coupling type is selected according to the matching and connection conditions of the coupling; according to the nominal torque and the shaft hole Diameter and shaft hole length are selected in specifications (model). In order to ensure the strength of the shaft and the key, after selecting the coupling model (specification), the shaft and key strength should be checked to determine the type of the coupling.


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