Core forming method for electric motors

Abstract

A method for forming a core for an electric motor disclosed by the present invention, wherein a metal strip moves in a continuous stepwise manner to continuously blank and form rotor laminations and a first blanking hole in at least one row of blanking areas of the metal strip, and the continuously formed rotor laminations are stacked on top of each other to form a rotor core; in subsequent blanking operations, a first stator core and a second stator core are formed, so that the assembly accuracy of the mutual assembly of the first stator core and the second stator core is relatively high, and the assembly accuracy between the stator core formed by the mutual assembly of the first stator core and the second stator core and the rotor core is also relatively high, thereby improving the working performance of the core.

Description

Technical Field

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

[0002] Electric 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 performance such as the quietness and loss of electric motors. Therefore, higher requirements are put forward for the production of cores in electric motors. However, in the prior art, the forming of the rotor core and the stator core of the electric motor are both blanked and formed through independent blanking dies. However, this method results in poor assembly consistency between the stator core and the rotor core, and a large gap error between them after mutual assembly, resulting in poor performance of the electric motor. Summary of the Invention

[0003] The purpose of the present invention is to design a core forming method for an electric motor to solve the above-mentioned technical deficiencies.

[0004] A core forming method for an electric motor designed by the present invention includes the following steps:

[0005] S1. The metal strip moves in a continuous stepwise manner to continuously blank and form rotor sheets and a first blanking hole in at least one row of blanking areas of the metal strip. The continuously formed rotor sheets are stacked on top of each other to form a rotor core.

[0006] S2. A plurality of first buckle points arranged in a circular array are blanked and formed along the circumferential part of the first blanking hole. The inner ends of the plurality of first buckle points are far from the edge of the first blanking hole.

[0007] S3. Continuous blanking is performed 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. Among them, the first stator sheet includes a ring body, a first stator inner hole formed in the ring body, and a plurality of tabs 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 tabs form a convex part on the circumferential side of the first stator core; the second blanking hole includes a through hole and a plurality of long notches arranged on the edge of the through hole. The plurality of long notches are arranged in a circular array.

[0008] S4. Continuous blanking is performed along the part near the outer end of each long notch to form a second stator inner hole, so that a plurality of inner concave parts arranged in a circular array are formed on the edge of the second stator inner hole. The inner concave parts are adapted to the ends of the tabs.

[0009] S5. A plurality of second buckle points are continuously blanked and formed in the side area of the second stator inner hole.

[0010] S6. Perform continuous blanking on the outer region away from the second buckling point to form the second stator thin sheet. After the continuously formed second stator thin sheets are stacked, they are connected to each other through the second buckling point to form the second stator core. The inner concave portion forms a connection groove on the inner wall of the second stator core.

[0011] According to the core forming method for the motor described above, in step S2, while the first buckling point is formed, a plurality of notch forming holes arranged in an annular array are punched and formed on the circumferential 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 buckling point is located outside the region between every two adjacent notch forming holes, so that in step S3, during the punching and forming of the first stator thin sheet, punching is also performed along the middle of each notch forming hole, so that the first stator thin sheet has a plurality of stator notches formed on the outer edge of the ring body.

[0012] According to the core forming method for the motor described above, in step S3, while the first stator thin sheet is formed, grooves are formed on the opposite sides of the outer ends of its tabs, and raised portions adapted to the grooves are formed on the opposite sides of the outer ends of the long notch.

[0013] According to the core forming method for the motor described above, before step S4, there is also an installation hole forming step, and its steps are as follows: Installation holes are continuously punched and formed in the regions on the opposite sides of the through hole.

[0014] According to the core forming method for the motor described above, in step S4, there is also an inner convex forming step, and its steps are as follows: During the punching and forming of the second stator inner hole, relief punching is also performed along the inner region away from the installation hole, so that inner convexes are formed on the inner walls on the opposite sides of the second stator inner hole.

[0015] According to the core forming method for the motor described above, after the long notch is partially removed, the raised portion is formed at the opening of the inner concave portion on the second stator inner hole.

[0016] According to the core forming method for the motor described above, in step S5, each second buckling point is formed in the region between every two adjacent inner concave portions.

[0017] According to the core forming method for the motor described above, before the installation hole forming step, there is also a second through-sheet hole forming step. Second through-sheet holes are punched and formed between every two adjacent long notches, and the forming positions of the second through-sheet holes are arranged corresponding to the forming positions of the second buckling points.

[0018] According to the core forming method for an electric motor described above, it further includes step S7, and the steps are as follows: fitting the first stator core into the stator hole of the second stator core, and respectively inserting the convex portions of the first stator core into the connection slots of the second stator core to form a composite stator core.

[0019] According to the core forming method for an electric motor described above, step S1 includes:

[0020] S11. During the continuous step-by-step movement of the metal strip, a plurality of process holes arranged in a circular array are punched and formed in at least one row of punching areas of the metal strip;

[0021] S12. A plurality of rotor slot shapes arranged in a circular array are punched and formed in the peripheral area around the process holes;

[0022] S13. A shaft hole is punched and formed in the central area surrounded by a plurality of process holes, and rotor through-sheet holes are selectively punched and formed beside each process hole;

[0023] S14. Rotor fastening points are punched and formed beside each process hole, and a plurality of first through-sheet holes arranged in a circular array are selectively punched and formed in the peripheral circular area far from the rotor slot shapes;

[0024] S15. Blanking treatment is performed along the outer side end side area of each rotor slot shape to form rotor thin sheets that fall into the rotor blanking channel and are locked. At the same time, the rotor blanking channel rotates to drive the rotor thin sheets inside it to rotate a predetermined angle. When the rotor thin sheets formed by blanking again and the rotor thin sheets that have rotated a predetermined angle are mutually laminated, the rotor slot shapes of the two rotor thin sheets are mutually misaligned, so that the rotor slot shapes of every two adjacent rotor thin sheets in the finally formed rotor core are mutually misaligned, making the slot-shaped through slots in the rotor core inclined.

[0025] The beneficial effects of the core forming method for an electric motor described in the present invention are as follows:

[0026] 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 one punching line, so that the assembly accuracy of the mutual assembly of the first stator core and the second stator core is relatively high, and the assembly accuracy between the stator core formed by the mutual assembly of the first stator core and the second stator core and the rotor core is also relatively high, thereby improving the working performance of the core and reducing the loss and noise of the electric motor.

[0027] 2. When the rotor core, the first stator core, and the second stator core of the method of the present invention are formed, the respective thin sheets are immediately laminated on each other after being formed, and are connected by buckling points after lamination. As a result, the lamination coefficient is relatively high, and the gap between the thin sheets is small. Then, the magnetic leakage generated by the gap of the motor core punching sheet is less, the eddy current loss is lower, and the torque and power density of the motor will increase accordingly.

[0028] In addition, when the rotor core, the first stator core, and the second stator core are formed, the use of multi-buckling point error precision control can ensure the consistency of the buckling point height during stamping, and the force is more balanced and stable when the buckling point is riveted and pressed in, avoiding the inconsistent and unstable lamination coefficient of the four-sided protruding sheets caused by the inconsistent buckling point height or the deformation of the buckling point shape, the unevenness and distortion of the entire core, the inability to meet the requirements of its geometric tolerance, the frequent change of height, and the situation that the subsequent process cannot be normally pressed into the stator core.

[0029] 3. The design with the rotor groove-shaped channel being inclined reduces the electromagnetic noise during the use of the motor, and the formed electromagnetic torque and induced electromotive force are approximately equal to the average value of the uniform distribution of the same rotor bar within a certain circumferential range, 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 the electromagnetic vibration and noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the layout drawing of the overall blanking method;

[0031] Figure 2 is the structural schematic diagram of the rotor thin sheet;

[0032] Figure 3 is the structural schematic diagram of the rotor core;

[0033] Figure 4 is the structural schematic diagram of the first stator core;

[0034] Figure 5 is the structural schematic diagram of the second stator core;

[0035] Figure 6 is the structural schematic diagram of the composite stator core;

[0036] Figure 7 is the installation structural schematic diagram of the through-sheet punch;

[0037] Figure 8 is the installation structural schematic diagram of the buckling point punch.

[0038] Reference numerals of the drawings: 1. Drawer plate cover; 2. Drawer plate; 3. Punch connecting rod; 4. Upper die holder; 5. Upper backing plate; 6. Punch fixing plate; 7. Equal-height sleeve rod; 8. Equal-height insert sleeve; 9. Limit block; 10. Stripper plate seat; 11. Stripper plate; 12. Tongue punch; 13. Cover plate; 14. Snap point punch; 15. Rectangular spring; 16. Rod body; 17. Tail hanging platform;

[0039] 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;

[0040] 201. First blanking hole; 202. Long-shaped notch; 203. Protrusion; 204. Through hole; 211. Process hole; 221. Rotor groove shape; 231. Rotor tongue hole; 232. Shaft hole; 241. Rotor snap point; 242. First tongue hole; 251. Rotor thin sheet; 261. Notch forming hole; 262. First snap point; 270. First stator thin sheet; 271. Ring body; 272. Tab; 273. Groove; 274. Stator notch; 275. First stator inner hole; 281. Second tongue hole; 291. Mounting hole; 301. Second blanking hole; 302. Inner protrusion; 303. Inner concave part; 311. Second snap point; 331. Second stator thin sheet; 332. Second stator inner hole;

[0041] 40. Rotor core; 401. Groove-shaped channel; 50. First stator core; 501. Protrusion; 60. Second stator core. Detailed implementation manners

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0043] Figure 1 As shown, the core forming method for a motor described in this embodiment includes the following steps:

[0044] S1. The metal strip 20 moves in a continuous step-by-step manner to continuously blank and form the rotor thin sheet 251 and the first blanking hole 201 in at least one row of punching areas of the metal strip 20. The continuously formed rotor thin sheets 251 are stacked on top of each other to form the rotor core 40, as Figure 2 and Figure 3As shown; the blanking of the metal strip 20 can be blanking in a single row of blanking areas, but can also be blanking in two or more rows of blanking areas. The steps for blanking and forming the rotor thin sheet 251 are as follows:

[0045] 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 blanked and formed in at least one row of blanking areas of the metal strip 20; generally, there are three process holes 211.

[0046] S12. A plurality of rotor slot shapes 221 arranged in a circular array are blanked and formed in the peripheral area around the process holes 211; the rotor slot shapes 221 are set to thirteen.

[0047] S13. A shaft hole 232 is blanked and formed in the central area surrounded by a plurality of process holes 211, and a rotor through-sheet hole 231 is selectively blanked and formed beside each process hole 211; among them, the shaft hole 232 will always be blanked and formed during blanking and forming, while the rotor through-sheet hole 231 is only blanked and formed after the number of stacked rotor thin sheets 251 reaches the preset requirement.

[0048] S14. A rotor buckle point 241 is blanked and formed beside each process hole 211, and a plurality of first through-sheet holes 242 arranged in a circular array are selectively blanked and formed in the outer peripheral circular area far from the rotor slot shape 221; among them, the rotor buckle point 241 is not blanked when forming the rotor through-sheet hole 231, and the first through-sheet hole 242 is only blanked and formed after the number of stacked first stator thin sheets 270 reaches the preset requirement. The rotor buckle point 241 is an arc-shaped structure, and the concave part communicates with the process hole 211.

[0049] S15. Blanking treatment is performed along the outer side area beside each rotor slot shape 221 to form the rotor thin sheet 251 and lock it in the rotor blanking channel. At the same time, the rotor blanking channel rotates to drive the rotor thin sheet 251 inside it to rotate a predetermined angle. When the newly formed rotor thin sheet 251 overlaps with the rotor thin sheet 251 that has rotated a predetermined angle, the rotor slot shapes 221 of the two rotor thin sheets 251 are arranged in a staggered manner, so that the rotor slot shapes 221 of every two adjacent rotor thin sheets 251 in the finally formed rotor core 40 are arranged in a staggered manner, making the slot-shaped through-channel in the rotor core 40 inclined. The slot-shaped channel 401 is composed of a plurality of staggered rotor slot shapes 221.

[0050] Based on step S1, the rotor thin sheets 251 after the rotor core 40 is formed are buckled through the rotor buckle points 241. When the number of stacked rotor thin sheets 251 reaches the preset requirement, the rotor buckle points 241 are not formed in the next step, and the rotor through-sheet holes 231 are blanked and formed beside each process to separate the latter rotor core 40 from the former rotor core 40.

[0051] S2. Along the circumferential part of the first blanking hole 201, a plurality of first fastening points 262 arranged in an annular array and a plurality of notch forming holes 261 arranged in an annular array are punched and formed. The inner ends of the plurality of first fastening points 262 are far 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 fastening point 262 is located outside the area between every two adjacent notch forming holes 261; the forming of the first fastening points 262 prepares for the immediate stacking and fastening after the first stator thin sheet 270 is punched and blanked. Among them, the first fastening points 262 can be square or circular structures. The first fastening 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.

[0052] S3. Continuous punching is performed along the middle of each notch forming hole 261 and the periphery of each first fastening point 262 to form the first stator thin sheet 270 and the second blanking hole 301. The continuously formed first stator thin sheets 270 are stacked and connected to each other through the first fastening points 262 to form the first stator core 50, as Figure 4 shown; among them, the first stator thin 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 tabs 272 formed on the edge of the ring body 271 and arranged in an annular array. Each first fastening point 262 is formed on the first stator thin sheet 270, and the tabs 272 form a convex part 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 long notches 202 arranged on the edge of the through hole 204. The plurality of long notches 202 are arranged in an annular array; when the stacking number of the first stator thin sheets 270 reaches a preset number, the first fastening points 262 are not formed in the next step, and a plurality of first through holes 242 arranged in an annular array are punched and formed in the outer annular area far from the rotor groove 221, so that the latter first stator core 50 is separated from the former first stator core 50.

[0053] S4. Continuous punching is performed along the part near the outer end of each long notch 202 to form the second stator inner hole 332, so that a plurality of inner concave parts 303 arranged in an annular array are formed on the edge of the second stator inner hole 332. The inner concave parts 303 are arranged in a matching manner with the ends of the tabs 272; this step prepares for the forming of the second stator thin sheet 331, and after the long notches 202 are partially removed, a raised part 203 is formed at the opening of the inner concave part 303 on the second stator inner hole 332.

[0054] S5. Continuously blank and form a plurality of second snap points 311 in the side area of the inner hole of the second stator, and each second snap point 311 is formed in the area between every two adjacent concave portions 303; the formation of the second snap points 311 prepares for the subsequent stacking and snap connection immediately after the blanking of the second stator thin sheet 331.

[0055] S6. Continuously blank along the outer area away from the second snap points 311 to form the second stator thin sheets 331. After the continuously formed second stator thin sheets 331 are stacked, they are connected to each other through the second snap points 311 to form the second stator core 60. The concave portions 303 cause the inner wall of the second stator core 60 to form connection grooves, as Figure 5 shown.

[0056] S7. Fit the first stator core 50 into the stator hole of the second stator core 60, and each convex portion 501 of the first stator core 50 is respectively inserted into the connection grooves of the second stator core 60 to form a composite stator core. Among them, the first stator core 50 will be pressed into the second stator core 60 on a stamping machine with a pressing force of 2000 kg to form a new composite stator core product, as Figure 6 shown. At the same time, it is necessary to ensure that the dimensional tolerances and geometric tolerances of the new core meet the requirements. Using multi-snap point error precision control not only ensures the dimensional requirements of a single core, the difference in the stacking coefficient of the two cores is controllable, but also reduces the risk of deformation of the new core after pressing, so as to reach a controllable range.

[0057] In step S3 of this embodiment, while the first stator thin sheet 270 is being formed, grooves 273 are formed on the opposite sides of the outer ends of its tabs 272, and protrusions 203 adapted to the grooves 273 are formed on the opposite sides of the outer ends of the long notches 202. The formation setting enables each tab 272 on the first stator core 50 to be clamped with each concave portion 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 relatively stable and reliable.

[0058] Before step S4 of this embodiment, there is also a step of forming the mounting holes 291. The steps are as follows: Mounting holes 291 are continuously blank and formed in the opposite side areas of the through holes 204. The formation of the mounting holes 291 enables the composite stator core to be fixed in the motor housing through fasteners.

[0059] In step S4 of this embodiment, it further includes an inner convex 302 forming step, and the steps are as follows: during the blanking and forming process of the inner hole 332 of the second stator, relief blanking is also performed along the inner region away from the mounting hole 291, so that inner convexes 302 are formed on the inner walls of the opposite sides of the inner hole 332 of the second stator. The forming of the inner convexes 302 is to make way for the forming of the mounting hole 291 to meet the product production requirements.

[0060] Before the mounting hole 291 forming step of this embodiment, it further includes a second through-sheet hole 281 forming step. The second through-sheet hole 281 is blanked and formed between every 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 snap point 311. When the stacking quantity of the second stator thin sheets 331 reaches the preset quantity, the second snap point 311 is not formed next time, but the second through-sheet hole 281 is blanked and formed between every two adjacent long notches 202, so that the latter second stator core 60 is separated from the former second stator core 60.

[0061] In this embodiment, the above-mentioned iron core forming method for the motor is realized by a continuous blanking die. Therefore, 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 groove shape 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 snap point 241 and the first through-sheet hole 242, a first blanking station 25 for blanking the rotor thin sheet 251, a fifth forming station 26 for forming the first snap point 262 and the notch forming hole 261, a second blanking station 27 for blanking the first stator thin sheet 270, a sixth forming station 28 for forming the second through-sheet hole 281, a seventh forming station 29 for forming the mounting hole 291, an eighth forming station 30 for forming the inner hole of the second stator, a ninth forming station 31 for forming a part of the second snap point 311, a tenth forming station 32 for forming another part of the second snap point 311, and a third blanking station 33 for blanking the second stator thin sheet 331.

[0062] Among them, the through-sheet punch 12 in the third forming station 23, the fourth forming station 24, and the sixth forming station 28 movably penetrates through the upper die of the continuous blanking die, and there is a movable cavity located above the through-sheet punch 12 in the upper die of the continuous blanking die. When the draw plate 2 is arranged in the movable cavity and abuts against the top end of the through-sheet punch 12, the through-sheet hole can be formed. When the draw plate 2 moves away from the top end of the through-sheet punch 12, the blanking of the through-sheet hole fails. The specific installation structure is as follows:

[0063] Such as 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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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