Precision machining of explosion-proof motor shaft
The last time talked about the rough machining of explosion-proof motor shaft, rough machining is the basis of the finish machining of explosion-proof motor shaft, for the parts that need to be finished to leave enough, but not too much processing margin to ensure the normal process of finishing.
The requirements of fine turning are higher and should be carried out by skilled workers on a more dense lathe. If the center hole of the rear axle of the coarse car is worn, the center hole must be re-corrected to obtain an accurate machining positioning benchmark, and then the fine car can be carried out.
When finishing the car, we must pay attention to the size between the two fine bearing, that is, we say the eyebrow, because its accuracy requirements are more strict, and the other pumping files use it as a benchmark.
After the completion of shaft finishing, it is also necessary to grind the parts such as the extraction position and shaft extension position. Similarly, during the finishing process, it is also necessary to leave a suitable processing allowance in the parts that need to be grinding. While ensuring the size of the grinding process, it is necessary to ensure that the machining surface reaches sufficient roughness requirements.
For particularly large explosion-proof motor shafts, limited to the size and ability control requirements of the equipment, the parts that should be ground in theory are completed by fine turning, but this must be guaranteed by high equipment accuracy and personnel writing skills.
Fine car of explosion-proof motor shaft
The requirements of fine turning are higher and should be carried out by skilled workers on a more precise lathe. If the center hole of the rear axle of the coarse car is worn, the center hole must be re-corrected to obtain an accurate machining positioning benchmark, and then the fine car can be carried out.
Dead center installation workpiece is more stable, but wear greater. The movable center has poor rigidity, but it can avoid wear between the workpiece and the center, so the movable center is widely used in cutting with higher speed.
The clamping method of fine turning is roughly the same as that of coarse turning. Fine turning, in addition to the need to grind the step to set aside grinding processing allowance (0.3~0.5 m), the rest of the shaft gear
All diameters and lengths are turned to the dimensions specified in the drawings. Face chamfer and grinding wheel run grooves are also removed. For small motors, in order to prevent the bending deformation of the shaft during press assembly, the core is pressed after the rough knurling, and then the bearing position, shaft extension position and the outer circle of the core are refined. Or first turn the armature gear, commutator gear, shaft gear, fan gear, etc., enlarge the bearing gear by 0.3~0.5 mm according to the drawing size, press the rotor, and then turn the bearing gear. The outer circle of the armature and the outer circle of the commutator are used to ensure the coaxiality of each part.
When finishing, we must pay attention to ensure the size between the two bearing brackets, that is, the axle shoulder, because its accuracy requirements are more stringent, and other shaft brackets use it as a benchmark.
The direction of improving the productivity of turning process is to improve the manufacturing precision of wool breakage to reduce the processing allowance. Improve the amount of turning, reduce the number of tool walking, in order to shorten the tool walking time and auxiliary time. The advanced technology used is high-speed cutting, strong cutting, multi-tool and multi-edge machining, copying turning and so on.
In order to improve the machining accuracy of turning, the factors affecting the machining accuracy should be analyzed according to the specific processing conditions and corresponding measures should be taken. Workpiece and tool clamping should be accurate and reliable: the rigidity of the process system is better, and the cutting edge of the tool should be carefully ground; The cutting depth and the amount of cutting is small, the cutting force is also small, so the elastic deformation of the process system is also small, and the quality of the processing surface can be improved.
When the shaft is refined, the cutting depth and cutting amount are often small, which can obtain higher machining accuracy and surface roughness
Shaft grinding
The parts at both ends of the motor shaft and the shaft extension require higher surface roughness. Although the use of fine car can meet the requirements, but the productivity is low, the cost is high. It is more economical to adopt the machining method of semi-finishing after grinding the outer circle.
When grinding, the workpiece is put between the two dead centers, and the core chuck and the dial drive the rotation. The purpose of using dead center is to reduce the gap between the center and the shaft
Vibration is eliminated to achieve the required machining accuracy. When grinding the outer circle, usually the longitudinal feed (longitudinal grinding method) is used, the grinding wheel is the main cutting movement, the workpiece rotates and makes a straight reciprocating movement with the table (longitudinal feed). At the end of each reciprocating stroke, the grinding wheel is cut in a radial direction. The longitudinal grinding method is characterized by high precision. For small motor shafts, transverse feed (transverse grinding method) is sometimes used because the processing part is not long. The grinding wheel is only used for lateral feed. The width of the grinding wheel should be greater than the length of the grinding part (generally more than 5 to 10 meters). When coarse grinding, the horizontal feed is 0.025~0.02 chamber meters per revolution) When fine grinding, the horizontal feed is 0.001~0.012 chamber meters/workpiece per revolution. The transverse grinding method is characterized by high efficiency, but the cylindricity deviation of the outer circle is large, and the eye must often use diamond force to trim the shape of the grinding wheel.
