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Do you know the technical requirements of the precision shafts?

Precision metal shafts are one of the typical parts often encountered in machines.It is mainly used to support transmission components, transmit torque and load bearing.

The shafts is a rotating parts, the length of which is larger than the diameter, generally consisting of the outer cylindrical surface, the conical surface, the inner hole and the thread and the corresponding end surface of the concentric shafts.

According to the shape of the structure, the shafts can be divided into optical axis, stepped shafts coupling shafts,hollow shafts and crank shafts.According to the material the shafts can be divided into stainless steel shafts,brass shafts,aluminum shafts,steel shaft etc...


Generally speaking, the length of the shaft is less than 5mm, which is called the short axis. The larger than 20mm is called the slender shaft, and most of the axes are between the two.


The precision and surface quality of precision shafts are generally required. The technical requirements are generally based on the main functions and working conditions of the shaft. Usually there are the following items:

(1) Dimensional accuracy
In order to determine the position of the shaft, the bearing journal is usually required to have a high dimensional accuracy (IT5~IT7). The journal size accuracy of the assembly drive is generally low (IT6~IT9).

(2) Geometric accuracy
The geometric accuracy of the precision metal shaft mainly refers to the roundness and cylindricity of the journal, the outer cone, the Morse taper, etc., and the tolerance should be limited to the dimensional tolerance. For inner and outer circular surfaces with high precision requirements, the allowable deviation shall be marked on the drawing.

(3) mutual positional accuracy
The positional accuracy requirements of precision metal shafts are mainly determined by the position and function of the shaft in the machine. Generally, the coaxiality of the journal of the assembled transmission member to the supporting journal should be ensured, otherwise the transmission accuracy of the transmission member (gear, etc.) will be affected and noise will be generated. For a normal precision shaft, the radial runout of the matching shaft section to the support journal is generally 0.01 to 0.03 mm, and the high precision shaft (such as the main shaft) is usually 0.001 to 0.005 mm.

(4) Surface roughness
Generally, the surface diameter of the shaft diameter matched with the transmission member is Ra2.5~0.63μm, and the surface roughness of the bearing shaft diameter matched with the bearing is Ra0.63~0.16μm.

After reading the above points, we should understand the functions, features and technical requirements of the precision shafts. Jiesheng Hardware engaged in the metal parts manufacturing industry for 12 years. We can provides solution to custom precision shafts for customers.