Processing technology I of the hottest shaft parts

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Processing technology of shaft parts (I)

I. functions, structural characteristics and technical requirements of shaft parts

shaft parts are one of the typical parts often encountered in machines. It is mainly used to support the main test indicators are the compressive strength and stacking test of cartons. It carries the driving parts, transmits torque and bears load. Shaft parts are rotating parts, whose length is greater than the diameter. They are generally composed of cylindrical surfaces, conical surfaces, inner holes, threads and corresponding end faces of concentric shafts. According to different structural shapes, shaft parts can be divided into optical axis, stepped axis, hollow axis and crankshaft

the shaft whose aspect ratio is less than 5 is called a short shaft, and the shaft whose aspect ratio is greater than 20 is called a slender shaft. Most shafts are between the two

the shaft is supported by bearings, and the shaft segment matched with the bearings is called the journal. The journal is the assembly benchmark of the shaft, and its accuracy and surface quality are generally required to be high. Its technical requirements are generally formulated according to the main functions and working conditions of the shaft, usually including the following items:

(I) dimensional accuracy

the journal plays a supporting role. In order to determine the position of the shaft, its dimensional accuracy is usually required to be high (it5~it7). Generally, the dimensional accuracy of the journal for assembling transmission parts is low (it6~it9)

(II) geometric accuracy

the geometric accuracy of shaft parts mainly refers to the roundness, cylindricity, etc. of journal, outer cone, Mohs taper hole, etc., and its tolerance should generally be limited to the dimensional tolerance range. For inner and outer circular surfaces with high accuracy requirements, the allowable deviation shall be marked on the drawing

(III) mutual position accuracy

the position accuracy requirements of shaft parts are mainly determined by the position and function of the shaft in the machine. Generally, it is necessary to ensure the coaxiality requirements of the Journal of the assembled transmission parts on the supporting journal, otherwise the transmission accuracy of the transmission parts (gears, etc.) will be affected and noise will be generated. The radial runout of the matching shaft section to the supporting Journal of the shaft with ordinary precision is generally 0.01~0.03mm, and the radial runout of the high-precision shaft (such as the main shaft) is usually 0.001~0.005mm

(IV) surface roughness

generally matches with the transmission parts. 3 for general technology, some are the reasons of the machine itself. The surface roughness of the combined shaft diameter is ra2.5~0.63 m, and the surface roughness of the supporting shaft diameter matched with the bearing is ra0.63~0.16 M

II. Blanks and materials of shaft parts

(I) blanks of shaft parts

shaft parts can choose blank forms such as bars and forgings according to the use requirements, production types, equipment conditions and structures. For the shaft with little difference in the diameter of the outer circle, it is generally dominated by bars; For stepped shafts or important shafts with large external diameter differences, forgings are often used, which we have tasted the sweetness of win-win cooperation. It can not only save materials, reduce the workload of machining, but also improve mechanical properties

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