Molding method of iron core for motor

Abstract

According to the iron core forming method for the motor, a metal material strip moves in a continuous stepping mode, rotor sheets and first blanking holes are continuously punched and formed in at least one row of punching areas of the metal material strip, and the continuously-formed rotor sheets are mutually stacked to form a rotor iron core; the first stator iron core and the second stator iron core are formed in the subsequent blanking, so that the assembly precision of mutual assembly of the first stator iron core and the second stator iron core is relatively high, and the assembly precision of the stator iron core and the rotor iron core formed by mutual assembly of the first stator iron core and the second stator iron core is also relatively high; therefore, the working performance of the iron core is improved.

Description

Technical Field

[0001] The invention relates to the technical field of iron core forming by stamping, in particular to an iron core forming method for a motor. Background Art

[0002] Motors are generally used in industrial equipment such as new energy vehicles, electrical appliances, and automated production equipment. However, with the development of society, people have higher and higher requirements for industrial equipment, especially in terms of motor performance such as quietness and loss. Therefore, higher requirements are placed on the production of iron cores in motors. In the prior art, the rotor core and stator core of the motor are formed by independent punching dies. However, this method makes the assembly consistency between the stator core and the rotor core poor, and leads to a large gap error between the two after mutual assembly, resulting in poor motor performance. Summary of the invention

[0003] The purpose of the present invention is to provide a method for forming an iron core for a motor designed to solve the deficiencies of the above-mentioned technology.

[0004] The present invention provides a method for forming an iron core for a motor, comprising the following steps: S1, the metal strip is moved in a continuous step-by-step manner to continuously punch out rotor sheets and first blanking holes in at least one row of punching areas of the metal strip, and the continuously formed rotor sheets are stacked on each other to form a rotor core; S2, punching and forming a plurality of first buckle points arranged in an annular array along the peripheral part of the first blanking hole, wherein the inner ends of the plurality of first buckle points are away from the edge of the first blanking hole; S3, continuously punching along the periphery of each first buckle point to form a first stator sheet and a second blanking hole, the continuously formed first stator sheets are stacked and connected to each other through the first buckle points to form a first stator core, wherein the first stator sheet includes a ring body, a first stator inner hole formed in the ring body, and a plurality of convex pieces formed on the edge of the ring body and arranged in a circular array, each first buckle point is formed on the first stator sheet, and the convex piece forms a convex portion on the circumferential side of the first stator core; the second blanking hole includes a through hole, and a plurality of elongated notches arranged on the edge of the through hole, and the plurality of elongated notches are arranged in a circular array; S4, continuously punching along the portion of each elongated notch adjacent to the outer end to form the second stator inner hole, so that the edge of the second stator inner hole forms a plurality of inner concave portions arranged in a circular array, and the inner concave portions are matched with the ends of the convex pieces; S5, continuously punching and forming a plurality of second buckle points in the side area of ​​the second stator inner hole; S6. Continuously punching along the outer area away from the second buckling point to form a second stator sheet. The continuously formed second stator sheets are stacked and connected to each other through the second buckling point to form a second stator core. The inner concave portion forms a connecting groove on the inner wall of the second stator core.

[0005] According to the above-mentioned method for forming an iron core for a motor, in step S2, while the first buckle point is formed, a plurality of notch forming holes arranged in an annular array are punched out on the peripheral side of the forming hole, the inner ends of the plurality of notch forming holes are close to the edge of the first blanking hole, and each first buckle point is respectively located on the outside of the area between each adjacent two notch forming holes, so that in the process of punching out the first stator sheet in step S3, punching is also performed along the middle of each notch forming hole, so that the first stator sheet has a plurality of stator notches formed on the outer edge of the ring body.

[0006] According to the above-mentioned method for forming an iron core for a motor, in step S3, when the first stator sheet is formed, grooves are formed on opposite sides of the outer ends of its protruding pieces, and protrusions matching the grooves are formed on opposite sides of the outer ends of the elongated recesses.

[0007] According to the above-mentioned method for forming an iron core for a motor, a mounting hole forming step is also included before step S4, wherein the mounting holes are formed by continuous punching at two opposite side regions of the through hole.

[0008] According to the above-mentioned method for forming the iron core for the motor, in step S4, it also includes an inner convex forming step, the steps of which are: during the punching and forming process of the inner hole of the second stator, an avoidance punching is also performed along the inner area away from the mounting hole, so that the inner walls on both sides of the inner hole of the second stator form an inner convexity.

[0009] According to the above-mentioned method for forming an iron core for a motor, after the elongated notch is partially removed, the protrusion is formed at the opening of the inner recess on the inner hole of the second stator.

[0010] According to the above-mentioned method for forming an iron core for a motor, in step S5, each second buckle point is formed in the area between each two adjacent inner recesses.

[0011] According to the above-mentioned method for forming an iron core for a motor, a second through-hole forming step is also included before the mounting hole forming step, in which a second through-hole is punched out between each two adjacent long recesses, and the second through-hole forming position is arranged corresponding to the second buckle point forming position.

[0012] According to the above-mentioned method for forming the core for the motor, it also includes step S7, which is: fitting the first stator core into the stator hole of the second stator core, and inserting the protrusions of the first stator core into the connecting grooves of the second stator core respectively to form a composite stator core.

[0013] According to the above-mentioned method for forming the iron core of the motor, step S1 comprises: S11, during the continuous step-by-step movement of the metal strip, a plurality of process holes arranged in a circular array are punched out in at least one row of punching areas of the metal strip; S12, punching and forming a plurality of rotor slots arranged in an annular array in a peripheral area arranged around the process hole; S13, punching out an axial hole in a central area surrounded by a plurality of process holes, and selectively punching out a rotor through-sheet hole beside each process hole; S14, punching and forming a rotor buckle point beside each process hole, and selectively punching and forming a plurality of first through-sheet holes arranged in an annular array in an outer annular area away from the rotor slot; S15. Punching is performed along the side area of ​​the outer end of each rotor slot to form a rotor sheet and drop it into the rotor blanking channel for locking. At the same time, the rotor blanking channel rotates to drive the rotor sheet inside it to rotate a predetermined angle. When the rotor sheet formed again by blanking is superimposed on the rotor sheet that has been rotated by the predetermined angle, the rotor slots of the two rotor sheets are offset from each other, so that the rotor slots of every two adjacent rotor sheets in the finally formed rotor core are offset from each other, so that the slot-shaped through-slots in the rotor core are inclined.

[0014] The iron core forming method for the motor described in the present invention has the following beneficial effects: 1. The method of the present invention enables the rotor core, the first stator core and the second stator core to be punched and formed on a punching line, so that the assembly accuracy of the first stator core and the second stator core is high, and the assembly accuracy between the stator core and the rotor core formed by the first stator core and the second stator core is also high, thereby improving the working performance of the core and reducing the loss and noise of the motor.

[0015] 2. When the rotor core, the first stator core and the second stator core are formed by the method of the present invention, the thin sheets are immediately superimposed on each other after forming and connected by buckle points after superposition, so that the superposition coefficient is high and the gap between the thin sheets is small. The leakage magnetic flux generated by the gap between the motor core punching sheets is less, the eddy current loss is lower, and the torque and power density of the motor will increase accordingly.

[0016] In addition, when the rotor core, the first stator core and the second stator core are formed, multi-point error precision control is used to ensure the consistency of the buckle point height during stamping, and the force is more balanced and stable when the buckle points are riveted and pressed in, avoiding inconsistent and unstable stacking coefficients of the convex pieces at four places due to inconsistent buckle point heights or deformation of the buckle point shapes, and the entire core is uneven and twisted and deformed, unable to meet its form and position tolerance requirements, and the height changes frequently, so that the subsequent process cannot be pressed into the stator core normally.

[0017] 3. The rotor slot channel is designed with an inclined setting, which reduces the electromagnetic noise when the motor is in use, and the electromagnetic torque and induced electromotive force formed are close to the average value of the same rotor bar evenly distributed within a circumference, which can effectively weaken the harmonic electromotive force generated by the tooth harmonic magnetic field, thereby weakening the additional torque caused by these harmonic magnetic fields and reducing electromagnetic vibration and noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the layout diagram of the overall blanking method; Figure 2 is a schematic diagram of the structure of the rotor sheet; Figure 3 It is a schematic diagram of the structure of the rotor core; Figure 4 is a structural schematic diagram of a first stator core; Figure 5 is a structural schematic diagram of the second stator core; Figure 6 It is a structural schematic diagram of a composite stator core; Figure 7 It is a schematic diagram of the installation structure of the through-piece punch; Figure 8 It is a schematic diagram of the installation structure of the buckle point punch.

[0019] Figure numbers: 1. drawer cover; 2. drawer plate; 3. punch connecting rod; 4. upper die seat; 5. upper pad; 6. punch fixing plate; 7. equal height sleeve rod; 8. equal height insert sleeve; 9. limit block; 10. unloading plate seat; 11. unloading plate; 12. through-piece punch; 13. cover plate; 14. buckle point punch; 15. rectangular spring; 16. rod body; 17. tail hanging platform; 20. Metal strip; 21. First forming station; 22. Second forming station; 23. Third forming station; 24. Fourth forming station; 25. First blanking station; 26. Fifth forming station; 27. Second blanking station; 28. Sixth forming station; 29. ​​Seventh forming station; 30. Eighth forming station; 31. Ninth forming station; 32. Tenth forming station; 33. Third blanking station; 201, first blanking hole; 202, elongated notch; 203, raised portion; 204, through hole; 211, process hole; 221, rotor slot; 231, rotor through-sheet hole; 232, shaft hole; 241, rotor buckle point; 242, first through-sheet hole; 251, rotor sheet; 261, notch forming hole; 262, first buckle point; 270, first stator sheet; 271, ring body; 272, convex piece; 273, groove; 274, stator notch; 275, first stator inner hole; 281, second through-sheet hole; 291, mounting hole; 301, second blanking hole; 302, inner convex; 303, inner concave; 311, second buckle point; 331, second stator sheet; 332, second stator inner hole; 40. rotor core; 401. slot-shaped channel; 50. first stator core; 501. convex portion; 60. second stator core. DETAILED DESCRIPTION

[0020] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0021] Figure 1 As shown, the iron core forming method for the motor described in this embodiment includes the following steps: S1, the metal strip 20 is moved in a continuous step-by-step manner to continuously punch out the rotor sheets 251 and the first blanking holes 201 in at least one row of punching areas of the metal strip 20, and the continuously formed rotor sheets 251 are stacked on each other to form the rotor core 40, such as Figure 2 and Figure 3 As shown; the punching of the metal strip 20 can be punched in one row of punching areas, but can also be punched in two or more rows of punching areas, wherein the steps of punching and forming the rotor sheet 251 include the following: S11 . During the continuous step-by-step movement of the metal strip 20 , a plurality of process holes 211 arranged in a circular array are punched out in at least one row of punching areas of the metal strip 20 . Generally, there are three process holes 211 .

[0022] S12, punching and forming a plurality of rotor slots 221 arranged in an annular array in the peripheral area around the process hole 211; the number of the rotor slots 221 is thirteen.

[0023] S13, an axial hole 232 is punched out in a central area surrounded by a plurality of process holes 211, and a rotor through-sheet hole 231 is selectively punched out beside each process hole 211; wherein, the axial hole 232 is always punched out during the punching and forming process, and the rotor through-sheet hole 231 is punched out only after the number of stacked rotor sheets 251 reaches a preset requirement.

[0024] S14, a rotor buckle point 241 is punched and formed beside each process hole 211, and a plurality of first through-sheet holes 242 arranged in an annular array are selectively punched and formed in the outer annular area away from the rotor slot shape 221; wherein, the rotor buckle point 241 is not punched when forming the rotor through-sheet hole 231, and the first through-sheet hole 242 is punched and formed only after the number of stacked first stator sheets 270 reaches a preset requirement, and the rotor buckle point 241 is an arc-shaped structure, and the concave part is connected to the process hole 211.

[0025] S15. Punching is performed along the side area of ​​the outer end of each rotor slot 221 to form a rotor sheet 251 and drop it into the rotor blanking channel for locking. At the same time, the rotor blanking channel rotates to drive the rotor sheet 251 inside it to rotate by a predetermined angle. When the rotor sheet 251 formed again by blanking and the rotor sheet 251 that has been rotated by a predetermined angle are superimposed on each other, the rotor slots 221 of the two rotor sheets 251 are offset from each other, so that the rotor slots 221 of every two adjacent rotor sheets 251 in the finally formed rotor core 40 are offset from each other, so that the slot-shaped through-slot in the rotor core 40 is inclined, wherein the slot-shaped channel 401 is composed of a plurality of rotor slots 221 arranged in an offset manner.

[0026] Based on step S1, after the rotor core 40 is formed, each rotor sheet 251 is fastened through the rotor fastening point 241. When the number of stacked rotor sheets 251 reaches the preset requirement, the rotor fastening point 241 is not formed next time, and the rotor through-sheet hole 231 is punched out on the side of each process to separate the subsequent rotor core 40 from the previous rotor core 40.

[0027] S2. A plurality of first buckle points 262 arranged in an annular array and a plurality of notch forming holes 261 arranged in an annular array are punched and formed along the peripheral side of the first blanking hole 201, the inner ends of the plurality of first buckle points 262 are away from the edge of the first blanking hole 201, the inner ends of the plurality of notch forming holes 261 are close to the edge of the first blanking hole 201, and each first buckle point 262 is respectively located on the outside of the area between each two adjacent notch forming holes 261; the first buckle points 262 are formed to prepare for the immediate stacking and buckling of the subsequent first stator sheet 270 after punching and blanking, wherein the first buckle points 262 can be a square or circular structure, the first buckle points 262 are in a concave structure on the upper surface of the metal strip 20, and in a convex structure corresponding to the concave structure on the lower surface of the metal strip 20.

[0028] S3, continuously punching out along the middle of each notch forming hole 261 and the periphery of each first buckle point 262 to form the first stator sheet 270 and the second blanking hole 301, and the continuously formed first stator sheets 270 are stacked and connected to each other through the first buckle points 262 to form the first stator core 50, such as Figure 4 As shown; wherein, the first stator sheet 270 includes a ring body 271, a first stator inner hole 275 formed in the ring body 271, a plurality of stator notches 274 formed on the outer edge of the ring body 271, and a plurality of protrusions 272 formed on the edge of the ring body 271 and arranged in a ring array, each first buckle point 262 is formed on the first stator sheet 270, and the protrusion 272 forms a convex portion 501 on the circumferential side of the first stator core 50; the second blanking hole 301 includes a through hole 204, and a plurality of elongated notches 202 arranged on the edge of the through hole 204, and the plurality of elongated notches 202 are arranged in a ring array; when the number of stacking of the first stator sheet 270 reaches a preset number, the first buckle point 262 is not formed next time, and a plurality of first through-sheet holes 242 arranged in a ring array are punched out in the outer annular area away from the rotor slot shape 221, so that the latter first stator core 50 is separated from the previous first stator core 50.

[0029] S4. Continuous punching is performed along the portion adjacent to the outer end of each elongated notch 202 to form the second stator inner hole 332, so that the edge of the second stator inner hole 332 is formed with a plurality of inner recesses 303 arranged in a circular array, and the inner recesses 303 are matched with the ends of the protruding pieces 272; this step prepares for the forming of the second stator sheet 331, and after the elongated notch 202 is partially removed, the protruding portion 203 is formed at the opening of the inner recess 303 on the second stator inner hole 332.

[0030] S5. Continuously punch and form a plurality of second buckle points 311 in the side area of ​​the second stator inner hole, and each second buckle point 311 is formed in the area between each two adjacent inner recesses 303; the forming of the second buckle points 311 is to prepare for the subsequent second stator sheet 331 to be immediately stacked and buckled after punching and blanking.

[0031] S6, continuously punching out along the outer area away from the second buckle point 311 to form the second stator sheet 331, the continuously formed second stator sheets 331 are stacked and connected to each other through the second buckle point 311 to form the second stator core 60, and the inner concave portion 303 forms a connecting groove on the inner wall of the second stator core 60, such as Figure 5 shown.

[0032] S7, fit the first stator core 50 into the stator hole of the second stator core 60, and insert the convex parts 501 of the first stator core 50 into the connecting grooves of the second stator core 60 respectively, so as to form a composite stator core. The first stator core 50 will be pressed into the second stator core 60 with a pressing force of 2000kg on a punching machine to form a new composite stator core product, such as Figure 6 As shown, it is necessary to ensure that the dimensional tolerance and form and position tolerance of the new core meet the requirements. The use of multi-point error precision control not only ensures the dimensional requirements of a single core, but also controls the difference in the stacking coefficients of the two cores, and reduces the risk of deformation of the new core after pressing in, thus reaching a controllable range.

[0033] In step S3 of the present embodiment, when the first stator sheet 270 is formed, grooves 273 are formed on opposite sides of the outer ends of its protrusions 272, and protrusions 203 adapted to the grooves 273 are formed on opposite sides of the outer ends of the elongated recesses 202. The forming and arrangement enable each protrusion 272 on the first stator core 50 to be respectively positioned between each inner recess 303 on the second stator core 60 through the protrusions 203 and the grooves 273 after the first stator core 50 is fitted into the stator hole of the second stator core 60, so that the installation of the first stator core 50 in the stator hole of the second stator core 60 is more stable and reliable.

[0034] Before step S4 of this embodiment, there is also a step of forming the mounting hole 291, which comprises the following steps: mounting holes 291 are continuously punched and formed in the opposite side areas of the through hole 204. The forming of the mounting holes 291 enables the composite stator core to be fixed in the motor housing by fasteners.

[0035] In step S4 of the present embodiment, a step of forming the inner convexity 302 is also included, and the steps are as follows: during the punching and forming process of the second stator inner hole 332, an evasive punching is also performed along the inner area away from the mounting hole 291, so that the inner walls on both sides of the second stator inner hole 332 form the inner convexity 302. The forming of the inner convexity 302 is to avoid the forming of the mounting hole 291 to meet the product production requirements.

[0036] Before the step of forming the mounting hole 291 in this embodiment, a step of forming the second through-sheet hole 281 is also included, wherein the second through-sheet hole 281 is punched and formed between each two adjacent long notches 202, and the forming position of the second through-sheet hole 281 is set corresponding to the forming position of the second buckle point 311. When the number of the stacked second stator sheets 331 reaches a preset number, the second buckle point 311 is not formed next time, and the second through-sheet hole 281 is punched and formed between each two adjacent long notches 202, so that the latter second stator core 60 is separated from the former second stator core 60.

[0037] In this embodiment, the iron core forming method for the motor is implemented by a continuous blanking die, so the continuous blanking die includes a first forming station 21 for forming the process hole 211, a second forming station 22 for forming the rotor slot 221, a third forming station 23 for forming the shaft hole 232 and the rotor through-sheet hole 231, a fourth forming station 24 for forming the rotor buckle point 241 and the first through-sheet hole 242, a first blanking station 25 for blanking the rotor sheet 251, and a first blanking station 26 for forming the first buckle point 262 and the notch forming hole. 261 is formed, a fifth forming station 26 is used for blanking the first stator sheet 270, a sixth forming station 28 is used for forming the second through-sheet hole 281, a seventh forming station 29 is used for forming the mounting hole 291, an eighth forming station 30 is used for forming the second stator inner hole, a ninth forming station 31 is used for forming a part of the second buckle point 311, a tenth forming station 32 is used for forming another part of the second buckle point 311, and a third blanking station 33 is used for blanking the second stator sheet 331.

[0038] Among them, the through-piece punch 12 in the third forming station 23, the fourth forming station 24 and the sixth forming station 28 is movably arranged in the upper die of the continuous punching die, and the upper die of the continuous punching die is provided with an active cavity located above the through-piece punch 12, and a draw plate 2 is arranged in the active cavity. When the draw plate 2 abuts against the top of the through-piece punch 12, a through-piece hole can be formed. When the draw plate 2 moves and leaves the top of the through-piece punch 12, the through-piece hole punching fails. The specific installation structure is as follows: like Figure 7As shown, the upper pad 5 and the punch fixing plate 6 are fixed to the upper die seat 4 by screws and pins; the through-piece punch 12 is fixed to the punch fixing plate 6 by the tail hanging platform 17, and the tail hanging platform 17 of the through-piece punch 12 is connected to the punch connecting rod 3 by the rod body 16 penetrated in the upper pad 5. The upper end of the punch connecting rod 3 is provided with a draw plate 2, and the draw plate 2 is movably arranged in the groove processed in the upper die seat 4. The upper surface of the draw plate 2 is covered with a draw plate cover 1, and the draw plate cover 1 is fixed to the upper die seat 4 by screws. The draw plate 2 moves forward and backward under the action of the cylinder, and the front end surface of the draw plate 2 is processed with an avoidance groove, so that the front end surface of the draw plate 2 is concave 1.7mm relative to other places. When the draw plate 2 is in the state as shown in FIG. Figure 2 , the drawing plate 2 is in contact with the punch connecting rod 3. In this state, the through-sheet punch 12 is in a working state during the stamping process. When the drawing plate 2 moves backward for a distance under the action of the cylinder, there will be a 1.7mm active distance between the punch connecting rod 3 and the drawing plate 2. During the stamping process, after the through-sheet punch 12 contacts the metal strip 20, due to the 1.7mm distance between the drawing plate 2 and the punch connecting rod 3, the through-sheet punch 12 will move upward for a distance. In this state, the through-sheet punch 12 will be in a non-working state. The above method realizes the automatic switching between the working state and the non-working state of the through-sheet punch 12, so as to realize batch control of the thickness of the product core stacking; the unloading plate 11 is fixed to the unloading plate seat 10 by screws and pins, and the unloading plate seat 10 is connected to the upper die seat 4 by a pull rod sleeve.

[0039] like Figure 8 As shown, the installation structure of the buckle point punch 14 in the fourth forming station 24, the fifth forming station 26 and the tenth forming station 32 is as follows: the upper pad 5 and the punch fixing plate 6 are fixed to the upper die seat 4 by screws and pins; the buckle point punch 14 is first installed in the contour insert sleeve 8 from the outside, and then installed into the mold together, the contour insert sleeve 8 is fixed to the punch fixing plate 6 by the tail hanging platform 17, the tail hanging platform 17 of the contour insert sleeve 8 is docked with the contour sleeve rod 7 through the clearance hole of the upper pad 5, and the upper end of the contour sleeve rod 7 is installed with a suitable rectangular The spring 15 is covered with a cover plate 13 which is fixed to the upper die seat 4 by screws. The buckle point punch 14 is always in working condition during the stamping process. A mounting groove is set in the area of ​​the unloading plate seat 10 corresponding to the contour sleeve 8. The limit block 9 is fixed in the mounting groove of the unloading plate seat 10 by screws. The unloading plate 11 is fixed to the unloading plate seat 10 by screws and pins. The unloading plate seat 10 is connected to the upper die seat 4. When the buckle point punch 14 is not in working condition, the cutting edge of the buckle point punch 14 is retracted into the positioning hole of the unloading plate 11 by 1.5 mm.

[0040] The matching relationship between the buckle point punch 14 and the contour insert 8 is a bilateral clearance match of 0.008mm, and the matching relationship between the contour insert 8 and the punch fixing plate 6 is a bilateral clearance match of 0.012mm, which ensures the positioning accuracy of the buckle point punch 14 and the contour insert 8. The total height error of all buckle point punches 14 and contour inserts 8 must be within 0.01mm. Therefore, the height is calculated and ground uniformly to ensure that the protrusion error of the buckle point punch 14 during stamping is within 0.02mm, and the height of the punched buckle point shape must also be within 0. 0.02mm, the contour sleeve rod 7 is provided with an avoidance hole docking with the tail hanging platform 17 of the buckle point punch 14, and the avoidance hole depth is finely processed and there is a gap of 0.01mm with the tail of the buckle point punch 14, which is used to ensure that when the buckle point punch 14 is stamped, only the contour sleeve 8 and the contour sleeve rod 7 are docked and matched with the spring force. The buckle point punch 14 is made of alloy material. Although it has high hardness, it is fragile and cannot be subjected to long-term stress. It is only necessary to ensure that the cutting edge of the buckle point punch 14 works. All contour sleeves 8 and limit blocks 9 maintain a certain distance H mm from each other in the non-working state. The limit blocks 9 are finely processed with a thickness tolerance of ±0.002mm. For example, when the punching depth of the buckle point punch 14 needs to be 0.5mm, all the contour sleeves 8 are ground uniformly to calculate the height value to ensure H=2mm. When the buckle point punch 14 is working, the contour sleeve 8 contacts the limit block 9, and the lower surface of the contour sleeve 8 of all the buckle point punches 14 is subjected to force. At the same time, the retreat force is transmitted to the contour sleeve rod 7, and the spring force of the rectangular spring 15 starts to rebound, ensuring that the stamping of the buckle point punch 14 is stable and the punching depth of the buckle point punch 14 is consistent.

[0041] Because of the influence of the precision of the punching machine equipment, the high-speed stamping speed, and the thickness of the stamping material, all the equal-height inserts 8 and the limit blocks 9 will not contact and bear force at the same time, and there will be a time difference in the contact and bearing force. This structure ensures the protrusion of the buckle point punch 14 in the stamping state through the processing precision and assembly precision of all parts, and there will not be a large height difference.

[0042] The selection of rectangular spring 15 model needs to be calculated based on the blanking force of a single buckle point or multiple buckle points to ensure that its spring force is greater than the blanking force and is within the range of 1.5 to 2 times the blanking force. It ensures that the buckle point height of the buckle point punch 14 is accurate and stable during stamping, and is not affected by the accuracy of the punching machine equipment, high-speed stamping speed, and thickness of the stamping material, and can eliminate the negative effects of these factors.

[0043] This structure can be used for a single buckle point punch 14, and can also be used for multiple buckle point punches 14 using the same set of structures at the same time.

Claims

1. A method for forming an iron core for a motor, characterized in that: The steps include: S1, the metal strip (20) moves in a continuous step-by-step manner to continuously punch out rotor sheets (251) and first blanking holes (201) in at least one row of punching areas of the metal strip (20), and the continuously formed rotor sheets (251) are stacked on top of each other to form a rotor core (40); S2, punching and forming a plurality of first buckle points (262) arranged in a ring array along the peripheral side of the first blanking hole (201), wherein the inner ends of the plurality of first buckle points (262) are away from the edge of the first blanking hole (201); S3, continuously punching along the periphery of each first buckle point (262) to form a first stator sheet (270) and a second blanking hole (301), and the continuously formed first stator sheets (270) are stacked and connected to each other through the first buckle points (262) to form a first stator core (50), wherein the first stator sheet (270) comprises a ring body (271), a first stator inner hole (275) formed in the ring body (271), and a plurality of protruding pieces (272) formed on the edge of the ring body (271) and arranged in a ring array, each first buckle point (262) is formed on the first stator sheet (270), and the protruding pieces (272) form a convex portion (501) on the circumferential side of the first stator core (50); the second blanking hole (301) comprises a through hole (204), and a plurality of elongated notches (202) arranged on the edge of the through hole (204), and the plurality of elongated notches (202) are arranged in a ring array; S4, performing continuous punching along the portion adjacent to the outer end of each elongated notch (202) to form a second stator inner hole, so that the edge of the second stator inner hole forms a plurality of inner recesses (303) arranged in a circular array, and the inner recesses (303) are arranged to fit the ends of the protruding pieces (272); S5, continuously punching and forming a plurality of second buckle points (311) in the side area of ​​the second stator inner hole; S6. Continuously punching along the outer area away from the second buckling point (311) to form second stator sheets (331); the continuously formed second stator sheets (331) are stacked and connected to each other through the second buckling point (311) to form a second stator core (60); the inner concave portion (303) forms a connecting groove on the inner wall of the second stator core (60).

2. The method for forming an iron core for a motor according to claim 1, characterized in that: In step S2, while the first buckle points (262) are formed, a plurality of notch forming holes (261) arranged in an annular array are punched out on the peripheral side of the forming hole, the inner ends of the plurality of notch forming holes (261) are close to the edge of the first blanking hole (201), and each first buckle point (262) is located on the outside of the area between each two adjacent notch forming holes (261), so that in the process of punching out the first stator sheet (270) in step S3, punching is also performed along the middle of each notch forming hole (261), so that the first stator sheet (270) has a plurality of stator notches (274) formed on the outer edge of the ring body (271).

3. The method for forming an iron core for a motor according to claim 1, characterized in that: In step S3, while the first stator sheet (270) is being formed, grooves (273) are formed on opposite sides of the outer ends of its protruding piece (272), and protruding portions (203) adapted to the grooves (273) are formed on opposite sides of the outer ends of the elongated recess (202), and each first buckling point (262) is formed on each protruding piece (272) of the first stator sheet (270).

4. The method for forming an iron core for a motor according to claim 1, characterized in that: Before step S4, a mounting hole (291) forming step is also included, the steps of which are: the mounting holes (291) are formed by continuous punching in the opposite two side regions of the through hole (204).

5. The method for forming an iron core for a motor according to claim 4, characterized in that: In step S4, an inner convex (302) forming step is also included, wherein during the punching and forming process of the inner hole of the second stator, an avoidance punching is also performed along the inner area away from the mounting hole (291), so that inner convexities (302) are formed on the inner walls on both sides of the inner hole of the second stator.

6. The method for forming an iron core for a motor according to claim 3, characterized in that: After the elongated notch (202) is partially removed, the protrusion (203) is formed at the opening of the inner recess (303) on the inner hole of the second stator.

7. The method for forming an iron core for a motor according to claim 4, characterized in that: In step S5, each second buckle point (311) is formed in the area between each two adjacent inner recesses (303).

8. The method for forming an iron core for a motor according to claim 7, characterized in that: Before the mounting hole (291) forming step, a second through-sheet hole (281) forming step is also included, wherein the second through-sheet hole (281) is punched and formed between each two adjacent elongated notches (202), and the forming position of the second through-sheet hole (281) is arranged corresponding to the forming position of the second buckle point (311).

9. The method for forming an iron core for a motor according to claim 1, characterized in that: The method further comprises step S7, which comprises: fitting the first stator core (50) into the stator hole of the second stator core (60), and inserting the protrusions (501) of the first stator core (50) into the connecting grooves of the second stator core (60) respectively, so as to form a composite stator core.

10. The method for forming an iron core for a motor according to any one of claims 1 to 9, characterized in that: Step S1 includes: S11, during the continuous step-by-step movement of the metal strip (20), a plurality of process holes (211) arranged in an annular array are punched out in at least one row of punching areas of the metal strip (20); S12, punching and forming a plurality of rotor slots (221) arranged in an annular array in a peripheral area arranged around the process hole (211); S13, punching and forming an axial hole in a central area surrounded by a plurality of process holes (211), and selectively punching and forming a rotor through-sheet hole (231) beside each process hole (211); S14, punching and forming a rotor buckle point (241) on the side of each process hole (211), and selectively punching and forming a plurality of first through-sheet holes (242) arranged in an annular array in an outer annular region away from the rotor slot shape (221); S15, performing a punching process along the side area of ​​the outer end of each rotor slot shape (221) to form a rotor sheet (251) and drop it into the rotor blanking channel for locking, while the rotor blanking channel rotates to drive the rotor sheet (251) inside it to rotate by a predetermined angle, when the rotor sheet (251) formed again by blanking and the rotor sheet (251) that has been rotated by the predetermined angle are superimposed on each other, the rotor slot shapes (221) of the two rotor sheets (251) are mutually offset, so that the rotor slot shapes (221) of each two adjacent rotor sheets (251) in the finally formed rotor core (40) are mutually offset, so that the slot-shaped through-slots in the rotor core (40) are inclined.

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