Design and manufacture of the mould for the stator core silicon steel sheet

There are many ways to design the motor, but there is only one main stator design. There are three parts in the motor stator. The first part is the stator core, the second part is the winding, and the third part is the frame.The stator core of silicon steel sheet after the use of stamping will form a small burr, this kind of burr indirectly affect the electromagnetic field, reduce the power of motor is more serious is that will cause damage to equipment, and eventually lead to equipment failure, how to better production equipment which requires us in the mold design and manufacturing to begin to consider.

1. Technical key points of stator core
(1) firstly, the stator core blanking size should be accurately controlled, and the length, ventilation slot and other equipment size should meet the design requirements.
(2) secondly, the blanking surface of stator core should be flawless. It is better to choose blanking without burrs for composition, and the weight of the core and all indexes should meet the requirements of motor installation.
(3) finally, the universal axial distance of stator core shall be about 0.025mm, and the blanking plate shall not appear wavy after pressing the equipment.The edge and tooth of stator core should not be warped obviously, and the overall design should not be warped obviously, so that the center can be well symmetrical.
2. Define the design scheme for preliminary research
According to the above analysis and draw a conclusion, due to the characteristics of this part and the reasons for demand, we consider that we should use progressive die, so as to improve production efficiency.Progressive mold is the workpiece out of a number of slots and pin mouth, to be out of a number of slots and pin mouth will be the rest of the strip punching appearance, but the progressive mold seems to be convenient, but there are still shortcomings.Its disadvantages: first, in the process of discharging and feeding, the progressive die has no roof device, which is very easy to cause the tooth rebound of the groove after punching [1].Second, due to the high hardness of the material, it is very easy to damage the concave and convex mold, reduce the service life.Third, the workpiece itself for concentricity requirements are very high, in the use of progressive die design and punch installation and manufacturing aspects are very difficult, at the same time is not conducive to ensure that the design of the workpiece size meet the standard.Fourth, due to the relatively large size of the workpiece, it may exceed the mounting size of the press after use, causing inconvenience to the later assembly.Therefore, the use of elastic blanking and blanking die can better solve these shortcomings.
3. Design all parts of the mold
In the mold design, generally because the size of the workpiece is larger than the general specifications, so the use of diagonal push and elastic ejecting principle to design, so as to avoid the maximum damage to the equipment in the process of film rebound.Direct use of one-way blanking die can effectively reduce the generation of waste materials, ensure the accuracy and make the connection of the die more compact, further reducing the cost of the die [2].
At the same time, when designing these main workpiece, we should consider what kind of machine tools are used for processing and manufacturing of each part, and also consider whether they are durable and easy to install after manufacturing.Analyze the style and characteristics of each mold, design and assemble each different part in batches, so that its assembly effect can be completed under the most simple premise.
3.1 Choose materials carefully
Due to the silicon steel sheet's own material, the silicon steel sheet's own density is relatively large, at the same time, the cutting edge is relatively large, the performance requirements of each component are very high, high temperature resistance, and the silicon steel sheet's density is stronger than the general material, so this kind of material is choose here.
3.2 design of punch and die
In the design, the punch can be directly cut into the material by means of slow-moving silk lines and directly processed into the punch.Based on the position with a nail and generally use about 6 ~ 8 screw firmly fixed in the plate, the length of the punch design for the length of the stripper plate itself and normal rubber added up to the sum of the minus punch sunken into the stripper plate 1 mm as a benchmark, and height of 50 ~ 60 mm, usually based on the mold die to punch deserve to be late.The whole die is used to cut and process the concave hole with the method of slow silk line cutting.After the design of both molds is completed, the results are calculated according to the data, and the installation is carried out successively. During the installation, the pressure center and the center of the die handle are usually overlaps with each other.
3.3 design the positioning parts
The positioning parts are designed in the same way as the basic design, using the guide ruler as the basis, and there is no change between materials. 0.1mm is reserved, and the guide ruler is fixed smoothly in the concave die with screws.Make use of the high density of T10A steel and keep the strength at hrc50-60 during heat treatment.Longitudinal retaining pin still leaves 3 retaining pin positions.
3.4 design method of discharging device
On the stator iron core after cutting most of the artifacts for the closed curve, it is easy to make notches chronic springback even after blanking deformation, especially among the above mentioned teeth and shape cock to cause equipment failure, so in the design of discharging device must be selecting when the elastic unloading and elastic lifter device [3].Generally in the design of the elastic lifting device is installed in the lower die.As a result, if the rubber is placed in the die, the die thickness of the die will continue to increase, which will greatly increase the investment and die research and design time.To save time, move the rubber from the inside to the outside of the mold, and place it under the retaining plate for easy replacement after reaching a certain life.The thickness of the elastic blanking plate is usually less than 25 mm, and the heat treatment hardness of the material is HRC43 ~ 47, while the T10A steel can no longer be used, and 45# steel should be used.
After the installation of the top plate, a preliminary study was conducted on the unloading plate. After the research, it was found that the thickness of the unloading plate is 30 mm is the most standard, and the hot hardness of the material is still about hrc43-47, and the steel grade is 45# instead of ordinary steel.
3.5 material selection and assembly of the backing plate
At the end of the design, a punch shall be installed in the upper backing plate. The thickness of the punch shall generally be about 30mm.The bottom plate plays a supporting role for the die, and the thickness is generally choose as 25 mm.The backing plate is the same material as the top material and the discharge plate.45# steel and materials with heat treatment hardness of HRC43 ~ 47 are choose.After these steps are completed, the whole equipment can be installed and debugged.
4 the most important point of mould
The blanking of this paper is for silicon steel sheet, so it has a high requirement for the shape and size.After blanking, there can be no burrs, which brings great difficulties to the whole design.The first consideration is to use a wire-cut machine in the design and manufacture of punch and die as much as possible.It can be repaired twice more by using slow-moving silk to ensure that the size and surface roughness of the finished products meet the requirements of the design as far as possible. During the design process, the influence brought by the machine tool can be reduced to facilitate the later installation and deployment of molds.The most important thing is that the gap between the punch and the die must be even after installation.Otherwise, there will be burrs.Therefore, the installation of the lower die should be carried out in the installation process. After the installation of the lower die, the punch should be adjusted to make the gap between the concave and convex dies uniform and error free, and then the upper die should be installed.Reduce reassembly times to avoid damage to the mold.
5 conclusion
The mould designed by this method conforms to the design concept after the later inspection, and the design structure is compact. At the same time, the material saving and production efficiency are also significantly improved.After the inspection, the equipment maintenance in the period and convenient adjustment of the equipment have a significant effect. The large-scale production of stator core is easy to be replaced even if the mold is worn out, which is suitable for large-scale production.The silicon steel sheet of stator core produced by this mold is completely in line with modern standards in shape structure, size and weight, and basically has no burr or deformation after production.So it works.