Stator core of a permanent magnet motor and assembly tool thereof

Abstract

The application provides a stator core of a permanent magnet motor and an assembling tool thereof, and relates to the field of motors. The stator core comprises first punching sheets, the first punching sheets are composed of a plurality of first slot teeth which are arranged along a circumference and are sequentially connected, a plurality of second punching sheets are arranged between two first punching sheets, the second punching sheets comprise a plurality of second slot teeth which are arranged along the circumference and are arranged at intervals, a magnetic yoke is arranged on the outer side of the first punching sheets and the second punching sheets, and the magnetic yoke is coaxially arranged with the first punching sheets. At least one first punching sheet is arranged between any two second punching sheets, and the number of the first punching sheets accounts for 20%-30% of the sum of the number of the first punching sheets and the number of the second punching sheets. The application has the effects of effectively inhibiting the cogging torque of the permanent magnet motor, improving the actual efficiency of the motor, reducing the torque ripple, and effectively improving the noise of the motor while ensuring the smoothness of the magnetic circuit.

Description

Technical Field

[0001] The present application relates to the field of motors, and in particular to a stator core of a permanent magnet motor and an assembly tool thereof. Background Art

[0002] Motors are common electrical components in industrial production. Permanent magnet motors (PMMs) are widely used in industrial production due to their high efficiency and compact size. A PMM typically consists of a stator (with winding coils) and a rotor (with permanent magnets).

[0003] Currently, if Figure 1 As shown, the tooth slots of the stator core are generally of open design, that is, the tooth slot portions 60 on the stator core punching sheets 6 are open, which can reduce the difficulty of winding and effectively improve the winding efficiency.

[0004] However, in this case, the cogging torque of the motor is large, which requires additional electrical power consumption, reduces the actual efficiency of the motor, and also increases the noise generated during the operation of the motor. Summary of the Invention

[0005] In order to improve the problem of electric power waste caused by defects in the stator core itself, the present application provides a stator core of a permanent magnet motor and an assembly tool thereof.

[0006] In a first aspect, the present application provides a stator core of a permanent magnet motor, which adopts the following technical solution:

[0007] A stator core of a permanent magnet motor includes a first punching sheet, wherein the first punching sheet is composed of a plurality of first slot teeth arranged along a circumference and connected in sequence, and a plurality of second punching sheets are provided between two first punching sheets, wherein the second punching sheets include a plurality of second slot teeth arranged along a circumference and spaced apart;

[0008] It also includes a magnetic yoke clamped on the outside of the first punching sheet and the second punching sheet, and the magnetic yoke is coaxially arranged with the first punching sheet.

[0009] By adopting the above technical solution, the uppermost and lowermost layers of the stator core of this case are composed of first punching sheets, and the middle part is filled with a number of second punching sheets. The first punching sheets are closed slot-shaped, and the second punching sheets are open slot-shaped, so that the stator core contains closed parts and semi-closed parts. While ensuring the smooth flow of the magnetic circuit, it effectively suppresses the cogging torque of the permanent magnet motor, improves the actual efficiency of the motor, reduces torque pulsation, and effectively improves the noise of the motor; at the same time, the first punching sheets and the second punching sheets are combined to form an iron core. Before the iron core is placed in the yoke, the iron core can be wound. Since the iron core is exposed, the intervention of the guide wire nozzle is not required, the winding slot full rate is high, and the space in the tooth slot can be utilized to the greatest extent, which is conducive to reducing the height of the iron core and thus reducing the overall volume of the motor; further, the stator core can be formed by assembling the yoke and the wound iron core.

[0010] Optionally, at least one first punching sheet is arranged between two first punching sheets, and the number of the first punching sheets accounts for 20-30% of the sum of the number of the first punching sheets and the number of the second punching sheets.

[0011] By adopting the above technical solution, the first punching sheet can be placed between the first punching sheets at the uppermost layer and the lowermost layer. When the second punching sheet is placed between two first punching sheets, the existing core structure is close to the present application, and the cogging torque is easy to be generated, which reduces the efficiency of the motor and lowers the strength of the core as a whole. When the number of the first punching sheets placed between two first punching sheets is too large, the utilization rate of the permanent magnet in the motor is reduced. Therefore, by limiting the number of the first punching sheets, a balance between reducing the cogging torque and improving the utilization rate of the permanent magnet can be achieved. Moreover, the number and arrangement of the first punching sheets between the uppermost layer and the lowermost layer can be adjusted according to the parameters required by the motor, i.e., the first punching sheet between the uppermost layer and the lowermost layer can be arranged between the first punching sheet at the uppermost layer and the second punching sheet, between the second punching sheet and the first punching sheet at the lowermost layer, or between two second punching sheets. When the number of the first punching sheets between the uppermost layer and the lowermost layer is more than two, the first punching sheets can be stacked in sequence or inserted at intervals.

[0012] Optionally, a plurality of first punching sheets form a first punching sheet group, and a plurality of second punching sheets form a second punching sheet group, and the first punching sheet group and the second punching sheet group are alternately stacked.

[0013] By adopting the above technical solution, the uppermost layer and the lowermost layer of the core are formed by the first punching sheet group. The number of the first punching sheets in the first punching sheet group can be adjusted according to requirements, and the number of the second punching sheets in the second punching sheet group can be adjusted according to requirements. By arranging the first punching sheet group and the second punching sheet group, the connection strength of the whole core can be improved without affecting the ratio of the number of the first punching sheets to the number of the second punching sheets, and the phenomenon of the core being scattered in actual use can be avoided.

[0014] Optionally, the bottom of the first slot tooth and the bottom of the second slot tooth are provided with rivet convex points, and the top of the first slot tooth and the top of the second slot tooth are provided with rivet concave grooves.

[0015] The rivet convex point of one first slot tooth is adaptively crimped in the rivet concave groove of an adjacent second slot tooth or another first slot tooth; and the rivet convex point of one second slot tooth is adaptively crimped in the rivet concave groove of an adjacent first slot tooth or another second slot tooth.

[0016] By adopting the technical scheme, when assembling the first punch piece group, the rivet protrusion of the upper first punch piece is pressed into the rivet recess of the lower first punch piece, an interference fit is formed between the rivet protrusion and the rivet recess through external extrusion, and then firm assembly of the two first punch pieces is realized; when connecting the first punch piece and the second punch piece, the plurality of second teeth of the second punch piece are respectively and one-to-one arranged on the plurality of first teeth of the first punch piece, and then external extrusion is performed to realize firm assembly of the first punch piece and the second punch piece; the shape of the rivet recess and the rivet protrusion can be preferably square, which plays a limiting role on the direction of the first teeth and the second teeth, and improves the assembly speed.

[0017] In a second aspect, the application provides an assembly tool for a stator core of a permanent magnet motor, which adopts the following technical scheme:

[0018] An assembly tool for a stator core of a permanent magnet motor, comprising a workbench, a first punch piece group releasing unit, a second punch piece group releasing unit and a pressure bonding unit.

[0019] The top of the workbench is provided with a first recess and a second recess which are in communication with each other, the first recess is located below the first punch piece group releasing unit and the second punch piece group releasing unit, and the second recess is located below the pressure bonding unit.

[0020] One end of the first recess is provided with a first hydraulic cylinder, and the push rod of the first hydraulic cylinder pushes the stacked first punch piece group and second punch piece group to the joint of the first recess and the second recess.

[0021] The joint is provided with a second hydraulic cylinder, and the push rod of the second hydraulic cylinder pushes the stacked first punch piece group and second punch piece group to below the pressure bonding unit.

[0022] The pressure bonding unit comprises a pressure head driven by a third hydraulic cylinder, and the pressure head presses the first punch piece group and the second punch piece group downward.

[0023] By adopting the technical scheme, the first blank group and the second blank group which have been adjusted in quantity and assembled are respectively placed into the first blank group releasing unit and the second blank group releasing unit; after the push rod of the first hydraulic cylinder moves to the lower side of the first blank group releasing unit, one first blank group is released from the first blank group releasing unit, and then the push rod of the first hydraulic cylinder pushes the first blank group to slide linearly in the first groove; when the first blank group moves to the lower side of the second blank group releasing unit, the second blank group is released and stacked above the first blank group, at this time, the top rivet buckle groove of the first blank group corresponds to the bottom rivet protrusion of the second blank group one by one; the push rod of the first hydraulic cylinder pushes the first blank group and the second blank group to slide linearly in the first groove and move to the joint, at this time, the push rod of the first hydraulic cylinder retreats, the push rod of the second hydraulic cylinder extends, so that the first blank group and the second blank group slide in the second groove; after moving to the lower side of the pressure head, the push rod of the third hydraulic cylinder extends, drives the pressure head downward, and makes the pressure head extrude the stacked first blank group and second blank group in the vertical direction, so that the bottom rivet protrusion of the second blank group is pressed into the top rivet buckle groove of the first blank group, the firm assembly of the first blank group and the second blank group is realized, the push rod of the third hydraulic cylinder retreats, and the push rod of the second hydraulic cylinder continues to push, so that the assembled first blank group and second blank group are pushed out to the outside of the second groove, and are convenient for centralized recovery.

[0024] Optionally, the push rod of the first hydraulic cylinder is provided with a receiving plate, and the top of the receiving plate is provided with a magnet for adsorbing the first blank group and the second blank group.

[0025] By adopting the above technical scheme, the released first blank group and second blank group are magnetically attracted by the magnet on the receiving plate, which can improve the landing accuracy of the first blank group and the second blank group, and can prevent the first blank group and the second blank group from moving together or separating from each other during the stacking and moving process, thereby improving the stability of the first blank group and the second blank group during the releasing and moving process through the magnetic attraction of the magnet.

[0026] Optionally, the joint is located between the other end of the first groove and one end of the second groove, and the magnet slides in the first groove.

[0027] The height of the groove bottom of the second groove is not higher than the top height of the magnet.

[0028] By adopting the above technical scheme, after the second hydraulic cylinder acts, the stacked first blank group and second blank group can be reliably and smoothly pushed into the second groove, and then the first blank group and the second blank group are pushed to the lower side of the crimping unit.

[0029] Optionally, the first punch group releasing unit and the second punch group releasing unit each comprise a tubular shell, and a pair of accommodating grooves are symmetrically arranged in the lower part of the shell;

[0030] A clamping strip is fitted in each of the pair of accommodating grooves, and a plurality of springs are arranged between one side of the clamping strip and the groove bottom of the accommodating groove.

[0031] By using the above technical solution, one side of the clamping strip is located outside the accommodating groove, so that the first punch group and the second punch group in the shell can be received. When the magnet moves to the lower part of the shell, the magnet will generate a magnetic attraction force on the first punch group or the second punch group in contact with the clamping strip, that is, there is a tendency for the first punch group or the second punch group to move downward. At this time, interference occurs between the first punch group or the second punch group and the clamping strip, so that the clamping strip tends to move horizontally, thereby compressing the spring. When one side of the clamping strip is completely pressed into the accommodating groove, the first punch group or the second punch group can be automatically released. The spring releases energy and rebounds to push the clamping strip back to its original position, preventing the next first punch group or second punch group from being released. That is, through the adsorption of the magnet on the first punch group or the second punch group, a vertical pulling force is generated, which drives the clamping strip to move horizontally, thereby releasing the limiting action on the first punch group or the second punch group and achieving the release of the first punch group or the second punch group.

[0032] Optionally, at least one pair of first limiting strips for limiting the rotation of the first punch group are arranged in the shell for placing the first punch group.

[0033] A plurality of second limiting strips are arranged in the shell for placing the second punch group, and any second tooth is limited by at least two second limiting strips.

[0034] By using the above technical solution, the first punch group is composed of a plurality of first punches, forming a tubular overall structure. A pair of first limiting strips are respectively and one-to-one fitted on the different outer sides of the opposite two first teeth, thereby limiting the first punch group. The second punch group is composed of a plurality of second punches, and the second punch is composed of a plurality of second teeth separated from each other. Therefore, the second punch group can be regarded as being composed of a plurality of second tooth groups, and at least two second limiting strips are required to limit any separated second tooth group. In this way, it can be ensured that all the second tooth groups can form a standard second punch group.

[0035] Optionally, the stiffness coefficient of the spring in the shell for placing the first punch group is greater than the stiffness coefficient of the spring in the shell for placing the second punch group.

[0036] By adopting the technical scheme, the magnet will reduce the adsorption force on the second punch piece group after adsorbing the first punch piece group, and thus, by reducing the stiffness coefficient of the spring corresponding to the second punch piece group, the second punch piece group can press the clamping strip to move horizontally, and automatic release of the second punch piece group is realized.

[0037] In summary, the present application includes the following advantages:

[0038] 1. The stator core is composed of two first punch pieces clamping a plurality of second punch pieces, the first punch piece is a closed slot shape, and the second punch piece is an open slot shape. While ensuring smooth magnetic circuit, the tooth slot torque of the permanent magnet motor is effectively suppressed, the actual efficiency of the motor is improved, the torque ripple is reduced, and the noise of the motor is effectively improved.

[0039] 2. By reasonably adding a plurality of first punch pieces between any two second punch pieces, the overall strength of the iron core can be improved. Moreover, by adding closed first punch pieces, the tooth slot torque can be reduced due to the excessive open area of the overall iron core, and the actual efficiency of the motor can be effectively improved.

[0040] 3. The stator core assembly tool is used to realize the stacking and automatic pressing of the first punch piece group and the second punch piece group under the cooperation of the first hydraulic cylinder, the second hydraulic cylinder and the third hydraulic cylinder, and the assembly efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is the prior art involved in the background art of the present application;

[0042] Figure 2 is a schematic front view of the first punch piece in the stator core;

[0043] Figure 3 is a schematic front view of the second punch piece in the stator core;

[0044] Figure 4 is a reference diagram of the combined state of the first punch piece and the second punch piece;

[0045] Figure 5 is a schematic front view of the magnetic yoke;

[0046] Figure 6 is a reference diagram of the combined state of the iron core and the magnetic yoke;

[0047] Figure 7 is a schematic side view of the first slot tooth in the first punch piece;

[0048] Figure 8 is a schematic side view of the second slot tooth in the second punch piece;

[0049] Figure 9 is a structural schematic view of the stator core assembly tool;

[0050] Figure 10 is a schematic plan view of a first lamination group release unit in a stator core assembly tool;

[0051] Figure 11 is a schematic plan view of a second lamination group release unit in a stator core assembly tool;

[0052] Figure 12 is Figure 10 is a schematic sectional view taken along the cutting line A-A in the figure;

[0053] In the figure: 1, first lamination; 10, first slot tooth; 101, rivet protrusion; 102, rivet recess;

[0054] 2, second lamination; 20, second slot tooth;

[0055] 3, magnetic yoke;

[0056] 41, workbench; 411, first recess; 412, second recess; 413, first hydraulic cylinder; 414, second hydraulic cylinder; 415, receiving plate; 416, magnet;

[0057] 42, first lamination group release unit; 421, housing; 4210, accommodating groove; 422, clamping strip; 423, spring; 424, first limiting strip; 425, second limiting strip;

[0058] 43, second lamination group release unit;

[0059] 44, pressing unit; 441, third hydraulic cylinder; 442, pressure head;

[0060] 45, support;

[0061] 5, iron core;

[0062] 6, stator core lamination; 60, slot tooth portion. DETAILED DESCRIPTION

[0063] The following will be described in detail with reference to the accompanying drawings. Figures 2-12 The application is further described.

[0064] The embodiment of the application discloses a stator core of a permanent magnet motor.

[0065] Referring to Figure 2 and 3 A stator core of a permanent magnet motor comprises a first lamination 1, the first lamination 1 is composed of a plurality of first slot teeth 10 arranged along a circumference and connected in sequence, and a plurality of second laminations 2 are further arranged between two first laminations 1, the second lamination 2 comprises a plurality of second slot teeth 20 arranged along a circumference and arranged at intervals; compared with a conventional stator core lamination 6, referring to Figure 4The first punching sheet 1 and the second punching sheet are combined to form the iron core 5 in the present application, see Figure 5 The magnetic yoke 3 is clamped outside the first punching sheet 1 and the second punching sheet 2, see Figure 6 The iron core 5 and the magnetic yoke 3 are combined to form the stator core, and the first punching sheet 1 is arranged at the top and the bottom of the iron core 5 to form a closed slot, so that part of the punching sheet in the iron core 5 is in a closed slot shape, and the remaining part of the punching sheet is in a semi-closed slot shape, which can effectively suppress the cogging torque of the motor, improve the power of the motor, and reduce the torque ripple, and the reduction of the torque ripple can also reduce the noise generated by the operation of the motor.

[0066] At least one first punching sheet 1 is arranged between the two first punching sheets 1, and the number of the first punching sheets 1 accounts for 20%-30% of the sum of the number of the first punching sheets 1 and the number of the second punching sheets 2. When the iron core 5 is only composed of two first punching sheets 1 clamping multiple second punching sheets 2, the overall strength of the iron core 5 is reduced, and the iron core 5 is prone to disintegration during the operation of the motor. Therefore, the first punching sheet 1 can be placed between the uppermost first punching sheet 1 and the lowermost first punching sheet 1 to improve the overall strength of the iron core 5 and reduce the cogging torque. The number of the first punching sheet 1 and the composition relationship between the second punching sheet 2 or other first punching sheet 1 can be reasonably and freely adjusted according to the required parameters of the motor.

[0067] The multiple first punching sheets 1 form a first punching sheet group, and the multiple second punching sheets 2 form a second punching sheet group. The first punching sheet group and the second punching sheet group are alternately stacked. The number of the first punching sheets 1 in the first punching sheet group and the number of the second punching sheets 2 in the second punching sheet group can be freely adjusted, as long as the number of the first punching sheets 1 accounts for 20%-30% of the number of the punching sheets in the iron core 5, so that the assembled iron core 5 can adapt to motors with different performance requirements. The single first punching sheet 1 and the single second punching sheet 2 are both formed by a punching equipment, and after the forming is completed, the punching equipment can directly punch and assemble multiple first punching sheets 1, that is, the first punching sheet group and the second punching sheet group can be controlled in corresponding number during manufacturing, and there is no need to separately assemble the first punching sheet group or the second punching sheet group.

[0068] See Figure 7 and 8 The bottom of the first slot tooth 10 and the bottom of the second slot tooth 20 are provided with rivet protrusions 101, and the top of the first slot tooth 10 and the top of the second slot tooth 20 are provided with rivet recesses 102.

[0069] The rivet protrusion 101 of one first slot tooth 10 is adaptively crimped in the rivet recess 102 of an adjacent one second slot tooth 20 or another first slot tooth 10. The rivet protrusion 101 is pressed into the rivet recess 102 to form a riveting effect, which has good connection effect and high aesthetic degree.

[0070] The embodiments of the present application also disclose an assembly tool for a stator core of a permanent magnet motor.

[0071] See also Figure 9 , including a workbench 41, a first punching group releasing unit 42, a second punching group releasing unit 43 and a crimping unit 44;

[0072] The top of the workbench 41 is provided with a first groove 411 and a second groove 412 which are interconnected. The first groove 411 is located below the first punching group release unit 42 and the second punching group release unit 43. The second groove 412 is located below the crimping unit 44.

[0073] A first hydraulic cylinder 413 is provided at one end of the first groove 411. A push rod of the first hydraulic cylinder 413 pushes the stacked first and second punching sheet groups to the junction of the first groove 411 and the second groove 412. The junction is located between the other end of the first groove 411 and one end of the second groove 412.

[0074] A second hydraulic cylinder 414 is provided at the junction of the first groove 411 and the second groove 412. The push rod of the second hydraulic cylinder 414 pushes the stacked first and second punching groups to the bottom of the crimping unit 44. A receiving plate 415 is provided on the push rod of the first hydraulic cylinder 413. A magnet 416 for adsorbing the first and second punching groups is provided on the top of the receiving plate 415. The magnet 416 slides within the first groove 411 under the push of the push rod of the first hydraulic cylinder 413. The bottom of the second groove 412 is no higher than the top of the magnet 416. This ensures that the push rod of the second hydraulic cylinder 414 can push the magnet 416, which adsorbs the first and second punching groups, into the second groove 412 and move it to the bottom of the crimping unit 44.

[0075] The crimping unit 44 includes a pressing head 442 driven by a third hydraulic cylinder 441. The pressing head 442 presses the first punching group and the second punching group downward so that the corresponding rivet protrusions 101 are pressed into the corresponding rivet grooves 102, thereby achieving a tight combination of the first punching group and the second punching group.

[0076] See also Figures 10-12 The first punching group releasing unit 42 and the second punching group releasing unit 43 each include a tubular housing 421 , and a pair of accommodating grooves 4210 are symmetrically provided at the lower portion of the housing 421 ;

[0077] A clamping strip 422 is adaptively provided in each of the pair of accommodating grooves 4210 . One side of the clamping strip 422 is located outside the accommodating groove 4210 , and a plurality of springs 423 are provided between the other side and the bottom of the accommodating groove 4210 .

[0078] The shell 421 for placing the first punching piece group is provided with at least one pair of first limiting strips 424 for limiting rotation of the first punching piece group; the first limiting strips 424 can limit rotation of the first punching piece group. The first limiting strips 424 and the shell 421 can be connected through connecting strips, or the first limiting strips 424 can be bent into L-shaped and the horizontal end of the first limiting strips 424 is fixedly connected with the inner wall of the shell 421, so that the first limiting strips 424 are in a fixed state and can reliably limit the first punching piece group.

[0079] The shell 421 for placing the second punching piece group is provided with a plurality of second limiting strips 425, and any second slot tooth 20 is limited by at least two second limiting strips 425. The second limiting strips 425 limit rotation of the second punching piece group and prevent horizontal movement of a single second punching piece group. The second limiting strips 425 and the first limiting strips 424 can be fixed by external connecting strips or by bending themselves, and limit the second punching piece group.

[0080] The stiffness coefficient of the spring 423 in the shell 421 for placing the first punching piece group is greater than the stiffness coefficient of the spring 423 in the shell 421 for placing the second punching piece group. In this way, the attractive force provided by the magnet 416 can suck the first punching piece group and the second punching piece group out of the first punching piece group release unit 42 and the second punching piece group release unit 43.

[0081] The first punching piece group release unit 42, the second punching piece group release unit 43 and the crimping unit 44 are fixed on the workbench 41 by the support 45 and there is a distance between the top of the workbench 41, which facilitates stacking of the first punching piece group and the second punching piece group; further, one stroke of the first hydraulic cylinder 413 can only realize assembly of one first punching piece group and one second punching piece group, and the iron core 5 is alternately composed of a plurality of first punching piece groups and a plurality of second punching piece groups, which can realize alternating stacking of a plurality of first punching piece groups and a plurality of second punching piece groups through reciprocating action of the first hydraulic cylinder 413, and finally perform crimping, or a plurality of crimping processes can be set, i.e. a plurality of workbenches 41 are set, the second recess 412 of the next workbench 41 is in communication with the first recess 411 of the previous workbench 41, so that the crimped product on one workbench 41 can enter the next workbench 41 for re-stacking of the first punching piece group and the second punching piece group.

[0082] The assembling tool of the stator core of the permanent magnet motor of the present application is used in the following process: the first hydraulic cylinder 413 drives the receiving plate 415 and the magnet 416 to move towards the lower part of the first lamination group releasing unit 42, under the attraction of the magnetic force of the magnet 416, the first lamination group pushes and drives the clamping strip 422 to move towards the horizontal direction, so that the clamping effect of the clamping strip 422 on the first lamination group is released, and the first lamination group can freely fall and be fixed on the magnet 416, the first hydraulic cylinder 413 continues to act, when the magnet 416 is displaced to the lower part of the second lamination group releasing unit 43, under the attraction of the magnetic force of the magnet 416, the second lamination group freely falls and is adsorbed on the top of the first lamination group; then the first hydraulic cylinder 413 continues to act, and pushes the stacked first lamination group and second lamination group to the joint of the first recess 411 and the second recess 412, at this time the push rod of the first hydraulic cylinder 413 retreats, the push rod of the second hydraulic cylinder 414 extends, and pushes the stacked first lamination group and second lamination group to the lower part of the crimping unit 44, finally the push rod of the third hydraulic cylinder 441 pushes the pressure head 442 to move downwards, so that the rivet buckle protrusion 101 at the bottom of the second lamination group is pressed into the rivet buckle groove 102 at the top of the first lamination group, and the firm assembly of the first lamination group and the second lamination group is realized.

[0083] The above are the preferred embodiments of the present application, which do not limit the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A stator core of a permanent magnet motor, characterized in that: The invention comprises a first punch (1), wherein the first punch (1) is composed of a plurality of first slot teeth (10) arranged along a circumference and connected in sequence, and a plurality of second punches (2) are arranged between two first punches (1), wherein the second punch (2) comprises a plurality of second slot teeth (20) arranged along a circumference and arranged at intervals; It also includes a magnetic yoke (3) clamped on the outside of the first punching sheet (1) and the second punching sheet (2), and the magnetic yoke (3) is coaxially arranged with the first punching sheet (1); An assembly tool for the stator core, comprising a workbench (41), a first punching sheet group releasing unit (42), a second punching sheet group releasing unit (43) and a crimping unit (44); The top of the workbench (41) is provided with a first groove (411) and a second groove (412) that are interconnected, the first groove (411) being located below the first punching group release unit (42) and the second punching group release unit (43), and the second groove (412) being located below the crimping unit (44); A first hydraulic cylinder (413) is provided at one end of the first groove (411), and a push rod of the first hydraulic cylinder (413) pushes the stacked first punching sheet group and the second punching sheet group to the connection point between the first groove (411) and the second groove (412); A second hydraulic cylinder (414) is provided at the junction of the first groove (411) and the second groove (412), and a push rod of the second hydraulic cylinder (414) pushes the stacked first punching sheet group and the second punching sheet group to the bottom of the crimping unit (44); The crimping unit (44) includes a pressing head (442) driven by a third hydraulic cylinder (441), and the pressing head (442) presses the first punching sheet group and the second punching sheet group downwards; A receiving plate (415) is provided on the push rod of the first hydraulic cylinder (413), and a magnet (416) for adsorbing the first punching sheet group and the second punching sheet group is provided on the top of the receiving plate (415); The height of the bottom of the second groove (412) is not higher than the top height of the magnet (416); The first punching group releasing unit (42) and the second punching group releasing unit (43) both comprise a tubular housing (421), and a pair of accommodating grooves (4210) are symmetrically provided at the lower portion of the housing (421); A clamping strip (422) is adaptively provided in each of the pair of accommodating grooves (4210), one side of the clamping strip (422) is located outside the accommodating groove (4210), and a plurality of springs (423) are provided between the other side and the bottom of the accommodating groove (4210).

2. The stator core of a permanent magnet motor according to claim 1, characterized in that: At least one first punching sheet (1) is further provided between the two first punching sheets (1), and the number of the first punching sheets (1) accounts for 20%-30% of the sum of the number of the first punching sheets (1) and the second punching sheets (2).

3. The stator core of a permanent magnet motor according to claim 2, characterized in that: A plurality of first punching sheets (1) form a first punching sheet group, and a plurality of second punching sheets (2) form a second punching sheet group. The first punching sheet group and the second punching sheet group are stacked alternately.

4. The stator core of a permanent magnet motor according to claim 2, characterized in that: The bottom of the first groove tooth (10) and the bottom of the second groove tooth (20) are both provided with rivet buckle protrusions (101), and the top of the first groove tooth (10) and the top of the second groove tooth (20) are both provided with rivet buckle grooves (102); The rivet protrusion (101) of a first groove tooth (10) is adaptively pressed into the rivet groove (102) of an adjacent second groove tooth (20) or another first groove tooth (10); The rivet buckle protrusion (101) of a second groove tooth (20) is adaptively pressed into the rivet buckle groove (102) of an adjacent first groove tooth (10) or another second groove tooth (20).

5. The stator core of a permanent magnet motor according to claim 1, characterized in that: At least one pair of first limiting bars (424) for limiting the rotation of the first punching group is provided in a housing (421) for accommodating the first punching group; A plurality of second limiting strips (425) are provided in a housing (421) for accommodating the second punching sheet group, and any second groove tooth (20) is limited by at least two second limiting strips (425).

6. The stator core of a permanent magnet motor according to claim 1, characterized in that: The spring constant of the spring (423) in the housing (421) for accommodating the first punching sheet group is greater than the spring constant of the spring (423) in the housing (421) for accommodating the second punching sheet group.

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