Couplings are the most commonly used connecting part in shaft system transmission of mechanical products.
Its function is to connect the two axes to rotate together to transfer torque and motion. The relative displacement of two connected axes is compensated to improve the transfer dynamic characteristics.
The scope of application covers many fields. Variety, large use. With the progress of science and technology, the types of mechanical products increase, and the performance of continuous improvement. In order to adapt to different working conditions, the coupling with different characteristics is required to achieve the desired effect.
Couplings function
Machine consists of four main parts: power machine - transmission - working machine - controller.
Coupling is used to connect the two shafts or shafts and the rotating body, in order to transfer motion and torque as the basic function of the general parts.
Coupling (Figure 1-1) two half couplings. 1 and 2 are fixedly mounted on the main and driven shafts with shaft hub connection.
Fittings 3, 4, 5, 6 (rigid body, elastomer) connect the two semi-couplings. Rigid coupling and flexible coupling.
The former only connects two shafts to transfer motion and torque, and does not have other functions. With metal or non-metallic elastic element connecting two and a half coupling, respectively called flexible coupling with metal elastic element non-metallic flexible coupling of elastic element. They take advantage of deformation of the elastic element to compensate for the relative offset of two axis, at the same time with different degree of shock absorption, buffer, and improve the function of the transmission system operating characteristics. Can play the role of overload safety protection is called safety coupling. All couplings can be joined or separated only by assembly and disassembly under shutdown.
Figure 1-1 Limited flexible diaphragm coupling
1/2: main/driven half coupling 5: middle segment 3/4: input/output end sheath 6: diaphragm, bolt group
In order to facilitate the design and selection of coupling, China has formulated GB/T12458-2003 "mechanical coupling classification" national standard. According to the classification standard, its classification has the following five levels:
1) Category: couplings are divided into four categories according to whether they have the compensation function and safety protection function of relative offset of two axes.
2) Group: the coupling is divided into three groups according to the relative offset principle of compensating two axes.
3) variety: the coupling is divided into varieties and named according to different working principles, structures, materials and characteristics. For example: gear coupling, diaphragm coupling, tire coupling…
4) Form: according to the connection, installation, matching, safety, lubrication and other needs of the same kind of coupling structure under the premise of the same, from the basic type of different forms.
5) Specifications: according to the size of the coupling and the nominal torque Tn that it can transfer for a long time, order by Arabic numbers from small to large. Their categories, groups, varieties and models are coded with their Chinese phonetic alphabet.
