On the basis of considering the above comprehensive factors, the coupling selection procedure is as follows:

(XNUMX) Choose standard coupling

When choosing a coupling, the designer should first choose the couplings that have been formulated as national standards, machinery industry standards, and national patents. Only when the existing standard couplings and patented couplings cannot meet the design needs Design the coupling by yourself.Our country has formulated a considerable number of different types of standard couplings that can basically meet different torque, speed and working conditions in different structural types and specifications.Some of these standard couplings are self-developed by our country and have undergone industrial experiments; some are converted according to the relevant standards of foreign industrial developed countries; some are digested and absorbed with reference to imported prototypes and developed by themselves.Some standard couplings are not only new high-performance domestically, but also advanced internationally, such as diaphragm couplings.In formulating standards, they generally go through strict procedures to ensure the quality of the standards.Standard couplings are mature and generally should be reliable. The key is to choose the right one.National patented couplings, such as flexible live pin couplings and sector-shaped flexible couplings, absorb the advantages of many old-fashioned flexible couplings and overcome their respective shortcomings. They are both high-performance and new technologies at home and abroad. Renew the coupling.

(XNUMX) Choose the type and type of coupling

Understand the comprehensive functions of the coupling (especially the flexible coupling) in the transmission system, and choose the type and type of the coupling from the overall design of the transmission system.According to the prime mover category and working load category, working speed, transmission accuracy, two-axis offset conditions, temperature, humidity, working environment and other comprehensive factors to select the type of coupling.

Select the structure of the coupling according to the needs of the supporting host. When the coupling is used in conjunction with the brake, a coupling with a brake wheel or a brake disc should be selected; when overload protection is required, a safety coupling should be selected ; When connecting with flanges, the flange type should be selected; for long-distance transmission, when the axial size of the connection is large, it is advisable to choose the middle or middle sleeve type.

(XNUMX) Calculation of coupling torque

The power of the power machine in the transmission system should be greater than the power required by the work machine.According to the power and speed of the power machine, the theoretical torque T of the high-speed end connected to the power machine can be calculated; according to the working condition coefficient K and other related 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 greater than the high-speed end T.

(XNUMX) Primary selection of coupling model

According to the calculated torque Tc, an approximate nominal torque Tn can be selected from the standard series, and the selection should satisfy Tn ≥ Tc.

The coupling model (specification) is preliminarily selected, and the allowable speed [n], the maximum radial dimension D and the axial dimension Lo of the coupling can be found from the standard, which should satisfy the coupling speed n ≤ [n] .

(XNUMX) Adjust the model according to the shaft diameter

The initially selected coupling size, that is, the diameter of the shaft hole d and the length of the shaft hole L, should meet the requirements of the shaft diameter of the driving and driven ends, otherwise the specifications of the coupling should be adjusted according to the shaft diameter d.It is a common phenomenon that the shaft diameters of the driving and driven ends are different. When the torque and speed are the same, and the shaft diameters of the driving and driven ends are different, the coupling model should be selected according to the larger shaft diameter.

In the newly designed transmission system, the seven shaft hole types in accordance with GB/T 3852 should be selected, and the J 1 shaft hole type is recommended to improve versatility and interchangeability. The length of the shaft hole is in accordance with the coupling product standard Provisions.

(XNUMX) Choose the connection type

The choice of coupling connection type depends on the connection type of the main and driven ends and the shaft. Generally, key connection is adopted, which is a unified key connection type and code. There are seven keyway types specified in GB/T 3852, four For keyless connections, the A-type key (flat key with single keyway) is more commonly used.

(XNUMX) Variety, type and specification of fixed coupling (model)

According to the comprehensive factors such as power machine and coupling load category, speed, working environment, etc., select the type of coupling, and select the coupling type according to factors such as the matching of the coupling and the connection situation; according to the nominal torque and shaft hole diameter Check the length of the shaft hole to finally determine the coupling model.

Generally, there are different degrees of relative offset between the two axes in shafting transmission, and flexible couplings should be selected; when the working load in the shafting transmission produces impacts and vibrations, flexible couplings should be selected to reduce vibration and buffer. For effect and economic considerations, flexible couplings with non-metallic elastic elements should be used.

The improper selection of couplings is common in our country. For example, gear couplings are widely used in the shaft transmission of metallurgical machinery and heavy machinery.Shock, vibration and two-axis offset are quite prominent disadvantages in the transmission of low-speed and heavy-duty shafting of metallurgical machinery and heavy machinery. Only the selection of elastic couplings with good vibration reduction and buffering effects can improve the working state of the transmission system. Both drum-shaped and straight-tooth couplings are rigid movable couplings.Due to the lack of vibration damping and buffering functions, the need for lubrication and sealing, the need for regular maintenance, the complicated manufacturing process, and the high cost, the drum-type gear coupling should have all teeth meshed (point contact) due to manufacturing errors. With the existence of, it is impossible for all teeth to mesh, and the bearing capacity is a theoretical value.In the past, there were few types of couplings and little room for choice. Nowadays, there are many elastic couplings. Among them, sector-shaped elastic couplings and elastic movable pin couplings are one of the reasonable choices to replace gear couplings.