Assembly method of SWC cross universal transmission shaft

The assembly of the cross universal coupling on the shaft is one of the keys to the installation of the cross universal coupling. The fit between the cross universal coupling and the shaft is mostly interference fit, and the connection is divided into keyed connection and keyless connection, and the shaft hole of the cross universal coupling is divided into cylindrical shaft hole and conical shaft hole.

Static press-in method is based on the different press-in force required during assembly, and is carried out by using pliers, jacks and manual or motorized presses. Static press-in method is generally used for tapered shaft holes. Because the static press-in method is limited by pressure machinery, it is difficult to apply a large force when the interference is large. At the same time, in the process of press-in, the uneven tiny convex peaks on the mating surface between the cross universal coupling and the shaft will be cut off, which will damage the mating surface. Therefore, this method is not widely used.

Inspection after assembly: After the cross universal coupling is assembled on the shaft, the verticality and coaxiality between the cross universal coupling and the shaft should be carefully checked. Generally, two dial indicators are set on the end face and excircle of the cross universal coupling. When turning the shaft, observe the total runout (including end face runout and radial runout) of the cross universal coupling, and judge the verticality and coaxiality of the cross universal coupling and the shaft. Cross universal couplings with different speeds and types have different requirements for total runout. After the cross universal coupling is assembled on the shaft, it is one of the main quality requirements for cross universal coupling assembly to make the deviation value of total runout within the tolerance range required by the design.
There are many reasons why the total runout value of cross universal coupling does not meet the requirements, which may be due to errors caused by machining. For the field assembly, the cross universal coupling is different from the shaft due to improper assembly of the key. The correct installation of the key should make the two sides of the key closely fit with the wall of the keyway. Generally, it should be checked by coloring method during assembly. If it is not well matched, it can be repaired with a file or a shovel to make it meet the requirements. There is generally a gap at the top of the key, about 0.1-0.2 mm. High-speed rotating machinery requires a high degree of coaxiality between the cross universal coupling and the shaft, which cannot be achieved by single-key connection, but can be improved by double-key connection or spline connection.