Application of new technology in the manufacture of motor core
With the development of China's economy, the demand for small and medium-sized motors has increased rapidly. The stamping process has adopted some new technologies and new technologies, which have improved the degree of mechanization and automation, improved working conditions, and improved the quality of the chips and labor productivity. At the same time, it has made some progress in exploring the reform of traditional crafts.
The coil sleeve is cut into a single row and the material utilization rate is low. In order to make more efficient use of electrical steel sheets and reduce product costs, people tend to change the shape of the punch and the arrangement of the progressive die stations, and adopt the cutting and punching process scheme. Some foreign companies have used Z-shaped slitting blanks (shaped hexagons) that have long been used in the canning industry for the cutting of motor punching sheets. The implementation of two or three rows of misplaced sets can save 7~15% of electrical steel sheets than straight cut strips. Ms. participated in some exchanges on the core manufacturing process.
The process of the air gap ring is gradually promoted
Adding a punching ring to the progressive die, the narrowing of the ring is equivalent to the air gap between the stator and the rotor. This process has been used in many countries since the 1960s. produce.
The advantages of the air gap process are: (1) the outer circumference of the rotor is not required to reduce the stray loss of the motor; (2) the straightness of the stator punch is good, which is beneficial to the automatic lamination device of the stator core, (3) After the air gap ring, the stator slot has a certain arc, which is beneficial to the pull-in automatic offline.
The punching ring process is adopted, and the positioning requirements are very accurate when punching the inner and outer rings and the air gap ring, and the mold manufacturing technology requires high.
High-speed automatic punching application
The two high-speed automatic punching machines are arranged in tandem, and the two-stage progressive die synchronous progressive punching is used. This tandem automatic punching line can punch motor punches with a diameter of 300~800 mm.
The advantages of using this process scheme are: (1) the punching pressure of each punch can be reduced, so that it is possible to punch a larger size punch using a standard automatic punching machine, and (2) the punching pressure of the punching machine is flexible, and the punching process is performed. The combination is also more flexible; (3) due to the smaller slider and die of the punching machine, the inertia is reduced, which is beneficial to increase the punching time of the punching machine: (4) The size of the progressive die can be reduced, which is beneficial to mold manufacturing, installation and Maintenance; (5) Due to the different wear of the fixed rotor die, it can be treated separately when replacing, reducing the amount of grinding work.
The use of automatic punching machines makes the loading and unloading devices more complicated, and at the same time limits the individual use of the punching machine.
Welding and bonding iron core development
After the small motor stator core is laminated, the old process of fixing with the clasp: the number of processes is large and the labor is large; the cleats need to be manually placed or manually welded, and the iron core punching may move when transported. The welding fixing method is first used for the stator core below the H200 base, and has been tested on the H225-250 base. With automatic lamination welding equipment, the welding is carried out directly on the press. high productivity. Three sets of iron core lamination welding equipment manufactured by a foreign company can produce up to 180 sets/hour when producing a diameter of 126 mm core.
In the past, only the micro-motor core was bonded, and it has been tried abroad for generators and motor cores. It is a phosphatized silicon steel sheet coated with a layer of micron thick solvent epoxy bonding material on a film casting machine. The laminated bonded core has stable mechanical properties and has little effect on the lamination coefficient.
Research and application of new technology
(1) Chemical etching method to produce "punching sheet". The chemical etching method is to chemically etch both sides of the silicon steel sheet, and apply the anti-corrosion agent to the punching sheet (retained portion), and the shapes coated on both sides should be accurately overlapped. Originally used in the photo method, the cost is high and the efficiency is low. Currently in the trial of silk screen printing methods in the textile industry. Advantages of the chemical etching method: 1) Do not die, save the cost of the mold, and reduce the production cycle: 2) No need for God, reduced investment, safe production, and no noise 3) No need for anti-image processing, because of the punching The anti-corrosion contact agent can be used as the insulation between the sheets, 4) no annealing, no burr and internal stress, no influence on the electromagnetic performance, and the soft silicon steel sheet which has been over-fired can be directly used.
The process is roughly as follows: 1) enlarge the drawing according to the part drawing; 2) zoom in to the actual part size; 3) copy multiple images in the step-multiplied camera and make the same negative two-point, after alignment Riveted together; 4) After the plate is coated, it is sent between two negative films, sensitized, developed, washed away from the unimaged portion of the coating; 5) corroded.
The chemical etching method can not only manufacture small motor punches and some parts, but also has a production line for producing turbine generator punches by etching.
(2) Powder metallurgy core. The iron powder is added with phosphorus, copper, molybdenum (0.5% of each of phosphorus and copper, and 1% of molybdenum), and the whole core is formed by pressing, sintering, etc., replacing the silicon steel sheet. The performance of the prepared sample: B25=1.4~1.5 special, B50=1.46~1.53 special; P10/50=4.0~4.5 watt/kg, P15/50=8.0~8.7 watt/kg. Close to the performance of D11 silicon steel sheet.
The powder core is manufactured by a simple method, and the process is: firstly, a small amount of fine organic matter is mixed into the iron powder, pressed into a prescribed shape under a pressure of 600 MW/m 2 , and then sent to the furnace for solidification. When the powder is selected, the magnetic properties of the powder core can be improved and made into a directional core. Its performance; B10=0.33~0.47 special, B50=1.12~1.23 special, the iron loss under the same volume is equivalent to 1.0 mm thick D11 silicon steel sheet. A foreign company tried on the stator of the ultra-small DC motor rotor and the single-phase AC commutator motor. The performance is very close to that of the silicon steel sheet; the efficiency is slightly lower, and the rated current is increased by about 5~10%. If it is reset according to the characteristics of the powder metallurgical core, the performance can be improved.
(3) Pressing the iron core. A foreign company recently took a V-shaped groove on a punching piece and then pressed it to form a core. This core eliminates the need for welding and gusseting, and the rotor core cast aluminum eliminates the need for false shafts.
