In the coil manufacturing aspect, the speed and automation of the winding machine are increasing day by day. The winding speed of the foreign automatic winding machine can reach up to 2500 laps/min. At the same time, two kinds of wires can be wound at the same time, and the slash line can be automatically counted and the insulation can be automatically wrapped. Belt, can automatically stop when a wire break occurs or a fault occurs. In order to cooperate with the pull-in automatic loosening machine, the wound coil is changed to a single row, and the winding mold structure is also changed accordingly. Multiple sets of coils can be wound at the same time, no need to disassemble the winding mold, and the wire can be directly pulled in after winding. Inside the sub-slot.
Slot insulation and slot die machining
In many countries, slot machining and slot die machining have adopted automatic machining and automatic slot insulation machines, which can insert 2~3 slots per second; slot die machines can insert 1 slot per second. Some small motors are insulated with epoxy powder deposition tanks and are produced on automatic lines, each of which takes only 6-8 seconds.
In the field of winding embedding, a pull-in stator automatic wire bonding machine has been developed in recent years. Initially used for single layer windings, now available for double layer windings. For example, there is a horizontal two-station automatic wire binding machine. The stator core is mounted on the sliding plate. After the first working position is pulled into the lower layer coil and the intervening layer is insulated, the sliding plate sends the stator core to the second station, and the shaping die is used. Press the end of the winding close to the end of the pull-in head to press it into a bell mouth, then return to the first station, pull in the upper line circle and insert the slot die.
In recent years, electromagnetic impact type wire bonding machines have been developed at home and abroad. It uses a capacitor to discharge, generating a large pulse current in the stator coil, and by the action of electromagnetic force, the wire is squeezed toward the bottom of the groove, and the end of the coil is simultaneously flared outward. Appropriate control of the electric pulse energy can make the wire be bent and wedged with each other without loosening, and the groove fullness can be increased to 90%. This method is suitable for the three-phase double-layer winding and the single-phase main-sub winding winding, that is, the lower layer coil or the main winding is first pressed to the bottom of the groove, and then the upper layer coil or the secondary winding is embedded.
Winding end shaping mechanization: In addition to shaping by electromagnetic impact method, mechanical shaping device can also be used to cover the winding end extension with a bowl forming die, and the inner sleeve rubber is inflated, and the press is axially pressurized from both ends. The tire expands outwardly, pressing the ends into the desired size and shape.
Winding end lashing mechanization: a kind of end banding machine in foreign countries, the lead awl can be chain knitted, and can wear 100 needles per minute. Some install the integral program control device on the binding machine, which can be tied in multiple layers according to the predetermined pattern; some end automatic binding machines use two needle bars to descend, rise and two tie bars to advance and retreat, and both ends of the winding can be simultaneously Binding.
In terms of insulation treatment, in recent years, countries have carried out many researches and reforms on the insulation treatment process of motor windings from the aspects of saving impregnating materials, shortening the dipping time, and striving to improve the insulation quality and improve the working conditions and environmental sanitation.
At present, the small motor drip immersion process has been matured and widely used. In addition, there are some other impregnation methods. One is the spray impregnation method, which is to mount the motor stator on a special rotating device, heat it to 115~120 °C, preheat for 2 minutes, and spray the resin from the pressure cylinder onto the rotating stator winding. It takes about 1~2 minutes. The resin penetrates into the winding under pressure and overflows to the inner diameter of the stator. Then it is evenly rolled by a rotating rubber wheel to evenly coat the inner wall of the stator with a thin layer of resin and make the slot die stick. Then it is heated by electric heating to cure it. The main feature is that the equipment is relatively simple and the immersion treatment time is short. Can be used to process hundreds of kilowatts of motor stator windings.
The other is a centrifugal impregnation method. Fast drying polyester solventless paint. In order to immerse the resin inside the stator winding, the winding end is sealed with a special clamp, and the core is clamped and rotated at a high speed, so that the resin penetrates into the stator slot and the winding end, and is rapidly solidified under heat, and the immersion temperature is room temperature. Or 50~70 °C. The entire immersion process takes only 5 to 8 minutes. Due to the strong centrifugal force, all the bubbles can be discharged, so the filling is dense and there is no shrinkage. The slot film and phase insulation can be omitted. For motors below 2 kW, the economy is more than 2 kWh, and the cost is not much, but the labor productivity is greatly improved. There is also a funnel casting method. When the method is applied to a DC armature winding, the armature is erected, the upper funnel is injected, and the required solventless resin lacquer is injected. The content of the hardener is adjusted, and when the resin is leaked, it begins to gel in the armature. The armature is then rotated in a horizontal position for curing to prevent the resin from accumulating on the armature side, affecting the balance.