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Functional characteristics and technical requirements of precision shafts

Before understanding the processing technology of precision shafts, we must first have a deep understanding and understanding of its functions, structural characteristics and technical requirements. Precision shafts are one of the typical parts often encountered in machines. It is mainly used to support transmission parts, transmit torque and carry loads.

Shaft hardware is a rotating body part, whose length is greater than its diameter, and is generally composed of the outer cylindrical surface, conical surface, inner hole, thread and corresponding end surface of the concentric shaft. According to different structural shapes, shaft parts can be divided into twist shafts, stepped shafts, hollow shafts and crankshafts. Shafts with an aspect ratio of less than 5 are called short shafts, those greater than 20 are called long shafts, and most shafts are in between.

The precision hardware shaft is supported by bearings, and the shaft segment that cooperates with the bearing is called the journal. The journal is the assembly benchmark of the shaft, and their accuracy and surface quality are generally required to be high. The technical requirements are generally formulated according to the main function and working conditions of the shaft, and usually include the following items:

Dimensional accuracy

In order to determine the position of the shaft, the journal that plays a supporting role usually requires high dimensional accuracy (IT5~IT7). The dimensional accuracy of the journal for assembling transmission parts is generally low (IT6~IT9).

Geometric accuracy

The geometric accuracy of the precision hardware shaft mainly refers to the roundness and cylindricity of the journal, outer tapered surface, Morse taper hole, etc., and its tolerance should generally be limited within the dimensional tolerance range. For the inner and outer circular surfaces with high precision requirements, the allowable deviation should be marked on the drawing.

Mutual position accuracy

The position accuracy requirements of the precision hardware shaft are mainly determined by the position and function of the shaft in the machine. Usually, it is necessary to ensure the coaxiality requirements of the journal of the assembly transmission parts to the support journal, otherwise the transmission accuracy of the transmission parts (gears, etc.) will be affected and noise will be generated. For ordinary precision shafts, the radial runout of the matching shaft section to the bearing journal is generally 0.01~0.03mm, and the high precision shaft (such as the main shaft) is usually 0.001~0.005mm.

Surface roughness

Generally, the surface roughness of the shaft diameter matched with the transmission part is Ra2.5~0.63μm, and the surface roughness of the support shaft diameter matched with the bearing is Ra0.63~0.16μm.

After reading the above points, you should understand the functions, characteristics and technical requirements of precision shafts. Jiesheng Hardware has been engaged in the hardware manufacturing industry for 12 years. It can customize the research and development and manufacture of non-standard, high-precision shafts and other hardware parts according to customer requirements.