Knowledge of mechanical design axis, quick get! - bearing knowledge

Axis is in the middle of the bearing or gear wheel in the middle or in the middle of the cylindrical objects, but there are also a few is square. Shaft is supporting and rotating parts with rotary to pass motion, torque or bending moment of mechanical parts. Generally for metal round rods, paragraphs can have different diameter, for rotary movement of the parts in the machine is installed on the shaft. 1, the classification of shaft, shaft type many, according to the axis of different shapes can be divided into direct axis, crank shaft, and flexible shaft. The crankshaft is often used in reciprocating machinery ( Such as internal combustion engine, air compressor, etc. ) , flexible shaft rotary motion can be flexibly to the required position, often used in medical equipment, we only discuss direct axis in the article. Direct axis bearing is different according to their heart can be divided into shaft, shaft and the shaft. Shaft: under bending moment and torque under at work, is the most common mechanical shaft, such as various of the reducer shaft, etc. ; Bring rotor spindle: used for bearing rotating components were not only under bending moment and torque, some of the spindle rotation, such as the axis of the railway vehicle, some of the spindle is not turning, such as the shaft supporting pulley and so on; Bring the heart shaft: mainly used to transfer torque and not under bending moment, such as to the long axis of the mobile crane, automobile drive shaft, etc. Shaft materials mainly adopts carbon steel or alloy steel, ductile iron or alloy cast iron may be adopted. Shaft work ability generally depends on the strength and stiffness, high speed also depends on the vibration stability; Bring the shaft 2, the material of shaft axis of commonly used material is carbon steel and alloy steel. Than carbon steel alloy steel and low price, small sensitivity to the stress concentration, mechanical performance is good, so are more widely application. The blank rolling of round steel is commonly used in steel shaft or forging. The internal organization of forgings is evener, good strength, so the important shaft forging billet should be adopted. 3, shaft structure design of shaft structure design is to determine all reasonable shape and structure size of shaft, and important step in the design for shaft. It by axis parts type, size and location, parts installed on the fixed way, the nature of the load, direction, size and distribution of bearing types and sizes of axis of blank, manufacturing and assembly process, installation and transportation, the shaft deformation and other factors. Designers can be designed according to the specific requirements of axial, when it is necessary to do a few scheme comparison, in order to select the best design scheme, the following is a general shaft structure design principle: save material, reduce weight, using strength, such as size or shape as far as possible big cross section shape coefficient of the cross section; Precise positioning, stable, easy to shaft parts assembly, disassembly and adjustment; Adopt measures to reduce stress concentration and improve the strength of the structure; To facilitate processing manufacturing and ensure accuracy; 4, axial location of axis parts and fixed axis parts of axial positioning and fixing methods commonly used have a shoulder, collar, locking collar, sleeve, round nut and lock washer with elastic ring, shaft end ring and conical surface, etc. 5, shaft repair. 1 shaft bending deformation correction shaft deformation is too large, can be cold pressing correction or local flame heating correction. Bearing parts should correct correction, especially should pay attention not to make the ladder shaft stress concentration due to correction around the corner. Bring about shaft bending deformation correction ( Left) And repair (journal of wear Right) 5. 2 journal wear repair usually use grinding first eliminate the geometry error of axis, then the metal spraying or brush plating, serious when can welding or set set of repair, set set when the set with the shaft for surplus to cooperate. 5. 3 spline, slotting, thread repair available gas welding or surfacing welding method to repair worn tooth profile, then on the basis of the wear and tear of the spline, milling spline. Keyway damage after, can be appropriately increase keyway or the old welding grooves, and with the new key. The thread damage on the shaft, should undertake surfacing, heavy threading. Bring spline slotting repair