Stator punching sheet, stator core and motor

Abstract

The utility model provides a stator punching sheet, a stator core and a motor. The stator punching sheet comprises first stator teeth and second stator teeth. In the circumferential direction of the stator punching sheet, the first stator teeth and the second stator teeth are arranged at intervals, and stator slots are formed between the first stator teeth and the second stator teeth; the first stator tooth is provided with a first tooth crown, the second stator tooth is provided with a second tooth crown, the first side of the first tooth crown is provided with an offset part, the offset part extends towards the first side of the second tooth crown, a first notch is formed between the offset part and the first side of the second tooth crown, and the center line of the first notch is offset from the center line of the corresponding stator slot. And auxiliary grooves are formed in the end parts of the first tooth crown and the second tooth crown. According to the utility model, the offset part and the auxiliary slot are arranged at the same time, a spatial phase difference is added to generated harmonic waves, strict periodicity of magnetic conductance change is destroyed from local to global, and the amplitude of the harmonic waves is reduced so as to weaken cogging torque.

Description

Technical Field

[0001] This utility model belongs to the field of motor technology, specifically relating to a stator lamination, a stator core, and a motor. Background Technology

[0002] In permanent magnet motors, the stator core is a crucial component of the motor's magnetic circuit. Current stator slots are typically semi-open, with the slots evenly distributed circumferentially across the stator core. Due to the stator's toothed and slotted structure, the alignment and misalignment of stator and rotor teeth during rotor rotation cause torque variations. This periodic flux change leads to torque pulsation, resulting in significant cogging torque. This change in stator cogging torque is one of the main causes of electromagnetic vibration and noise in the motor. The cogging torque varies with the relative position of the stator and rotor. Typically, the stator slots are evenly distributed circumferentially, and the air gap permeability changes with strict periodicity, resulting in distinct fundamental and harmonic components in the cogging torque. The stator tooth harmonics have lower orders and larger amplitudes, leading to significant cogging torque pulsation. This large cogging torque pulsation, superimposed on the motor's electromagnetic torque, further exacerbates electromagnetic torque pulsation, affecting the motor's control accuracy. The pulsating torque causes mechanical vibration in both the stator and rotor, affecting the motor's operational stability. It can also propagate through the structure, causing vibration in the motor housing and generating noise. Utility Model Content

[0003] This invention provides a stator lamination, a stator core, and a motor, which can solve the technical problem that the existing stator core structure has a strictly periodic change in air gap magnetic permeability, and the cogging torque exhibits obvious fundamental and harmonic components, resulting in low stator tooth harmonic order and large amplitude, leading to large cogging torque pulsation.

[0004] This utility model provides a stator lamination, which includes a first stator tooth and a second stator tooth;

[0005] In the circumferential direction of the stator lamination, the first stator tooth and the second stator tooth are spaced apart, and a stator groove is formed between the first stator tooth and the second stator tooth;

[0006] The first stator tooth has a first crown, and the second stator tooth has a second crown. An offset portion is provided on the first side of the first crown, and the offset portion extends to the first side of the second crown. A first groove is formed between the offset portion and the first side of the second crown. The center line of the first groove is offset relative to the center line of the stator groove, and auxiliary grooves are provided at the ends of both the first crown and the second crown.

[0007] In some embodiments, the first stator tooth is provided on both sides of the second stator tooth, and a second groove is formed between the second side of the second tooth crown and the second side of the first tooth crown, and the center line of the second groove coincides with the center line of the corresponding stator groove.

[0008] In some embodiments, the stator lamination is provided with a plurality of first stator teeth and second stator teeth in the circumferential direction, the number of first stator teeth is greater than the number of second stator teeth, and a plurality of first stator teeth are provided between adjacent second stator teeth.

[0009] In some embodiments, three first stator teeth are provided between adjacent second stator teeth.

[0010] In some embodiments, the ends of both the first crown and the second crown have two auxiliary grooves.

[0011] In some embodiments, in the circumferential direction of the stator lamination, the width of the first tooth crown and the width of the second tooth crown are both W1, and the width of the auxiliary groove is W2, wherein the width W2 satisfies: 0.125*W1≤W2≤0.25*W1.

[0012] In some embodiments, the spacing between the two auxiliary slots in the circumferential direction of the stator lamination is W3, and the spacing W3 satisfies: 1*W2≤W3≤1.5*W2.

[0013] In some embodiments, in the circumferential direction of the stator lamination, the distance between the groove wall of the auxiliary groove near the outer wall of the tooth crown and the corresponding outer wall of the tooth crown is W4, and the distance W4 satisfies: 0.06*W1≤W4≤0.25*W1.

[0014] In some embodiments, the depth of the auxiliary groove in the radial direction of the stator lamination is H, and the depth H satisfies: 0.08*W1≤H≤0.17*W1.

[0015] A stator core includes a plurality of stator laminations, wherein the stator laminations are as described above, and the plurality of stator laminations are stacked to form a multi-segment core unit in the axial direction of the stator core.

[0016] In some embodiments, the multiple core units include at least a first core segment and a second core segment stacked sequentially. Along the circumferential direction of the stator core, the projection of the offset portion of the first core segment is located on the second side of the first tooth crown of the second core segment, and the projection of the offset portion of the second core segment is located on the second side of the first tooth crown of the first core segment.

[0017] In some embodiments, the first and second core segments have the same structure. Along the axial direction of the stator core, the stator laminations of the first core segment are stacked in a first direction, and the stator laminations of the second core segment are flipped 180° and stacked in the first direction, so that the projection of the offset portion of the first core segment is located on the second side of the first tooth crown of the second core segment, and the projection of the offset portion of the second core segment is located on the second side of the first tooth crown of the first core segment.

[0018] An electric motor includes a stator core, wherein the stator core is as described above.

[0019] The stator lamination, stator core, and motor provided by this utility model have the following beneficial effects:

[0020] This invention increases the frequency of reluctance variation by adding auxiliary slots to the tooth crown, resulting in a finer distribution of air gap permeability. This introduces a new permeability period, generating additional harmonic components with opposite phase to the original permeability harmonics, thus reducing the amplitude of local reluctance abrupt changes. By adding an offset section, the permeability distribution of the entire stator lamination exhibits a non-uniform periodicity. The permeability fluctuations of the stator slots and auxiliary slots are spatially misaligned, resulting in a smoother equivalent permeability distribution after superposition. Simultaneously, the offset section and auxiliary slots add a spatial phase difference to the generated harmonics. The combination of the auxiliary slot and the first slot disrupts the strict periodicity of permeability variation from local to global perspectives, decomposing the fundamental component of the cogging torque into multiple lower-amplitude high-frequency components. This results in a widened and lower-amplitude characteristic, reducing harmonic amplitude and thus weakening the cogging torque, reducing electromagnetic vibration and noise. Attached Figure Description

[0021] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the stator lamination according to an embodiment of the present utility model;

[0023] Figure 2 This is a schematic diagram of the first stator tooth and the second stator tooth according to an embodiment of the present utility model;

[0024] Figure 3 This is a schematic diagram of the first slot and the second slot according to an embodiment of the present utility model;

[0025] Figure 4This is a schematic diagram of an embodiment of the present invention where three first stator teeth are provided between adjacent second stator teeth;

[0026] Figure 5 This is a schematic diagram of the width W1, width W2, spacing distance W3, distance W4, and depth H of an embodiment of the present utility model;

[0027] Figure 6 This is a schematic diagram of the stator core according to an embodiment of the present utility model;

[0028] Figure 7 This is a schematic diagram of the first and second core segments according to an embodiment of the present invention;

[0029] Figure 8 A schematic diagram illustrating the stator core cogging torque when two auxiliary slots are provided in an embodiment of this utility model;

[0030] Figure 9 This is a schematic diagram of the stator core cogging torque when the first slot and the second slot are provided in an embodiment of the present invention.

[0031] Figure 10 This is a schematic diagram of the stator core cogging torque when the first slot and auxiliary slot are provided in an embodiment of the present invention.

[0032] Attached Figures: 1-First stator tooth; 101-First crown; 11-First side of the first crown; 12-Second side of the first crown; 2-Second stator tooth; 201-Second crown; 21-First side of the second crown; 22-Second side of the second crown; 3-Stator slot; 4-Offset section; 5-First slot opening; 6-Auxiliary slot; 7-Second slot opening; 8-First section of iron core; 9-Second section of iron core. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0034] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0035] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used here to describe the spatial positional relationship of a device or feature as shown in the figure with other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation of the device as described in the figure. For example, if a device in the figure is inverted, a device described as "above" or "on top of" other devices or structures will subsequently be positioned as "below" or "under" other devices or structures.

[0036] See also Figures 1 to 3 As shown, according to an embodiment of the present invention, a stator lamination is provided, which includes a first stator tooth 1 and a second stator tooth 2; the first stator tooth 1 and the second stator tooth 2 are spaced apart in the circumferential direction of the stator lamination, and a stator groove 3 is formed between the first stator tooth 1 and the second stator tooth 2; the first stator tooth 1 has a first tooth crown 101, the second stator tooth 2 has a second tooth crown 201, an offset portion 4 is provided on the first side 11 of the first tooth crown 101, the offset portion 4 extends toward the first side 21 of the second tooth crown 201, a first groove 5 is formed between the offset portion 4 and the first side 21 of the second tooth crown 201, the center line of the first groove 5 is offset relative to the center line of the stator groove 3, and an auxiliary groove 6 is provided at the ends of both the first tooth crown 101 and the second tooth crown 201.

[0037] It is worth noting that the stator lamination includes a yoke and teeth. The yoke is annular, and multiple teeth are arranged circumferentially on the yoke. The main function of the yoke is to connect the teeth into a whole, forming a closed magnetic circuit. The teeth are protrusions on the stator lamination used to fix and position the stator windings. The main function of the teeth is to fix and position the stator windings, and also to serve as the path for air gap magnetic flux to pass through. In this embodiment, the first stator tooth 1 and the second stator tooth 2 are tooth structures, which are arranged on the yoke, specifically on the radially inner side of the yoke. In other embodiments, the first stator tooth 1 and the second stator tooth 2 can also be arranged on the radially outer side of the yoke. The teeth specifically include a tooth body and a tooth crown. One end of the tooth body is connected to the yoke, and the other end of the tooth body is the tooth crown, which extends from the end of the tooth body to both sides. The function of the tooth crown is to guide the magnetic field and fix the windings. The part on the stator lamination used to hold the stator winding is the slot, which is located between the teeth. The shape and size of the slot need to be set according to the specifications of the stator winding to ensure that the winding can be tightly embedded. In this embodiment, the stator slot 3 formed between the teeth of the first stator tooth 1 and the second stator tooth 2 is the slot.

[0038] Specifically, the stator lamination in this embodiment includes a first stator tooth 1 and a second stator tooth 2. One end of the first stator tooth 1 and the second stator tooth 2 are connected to the radially inner side of the yoke, and the other end of the first stator tooth 1 and the second stator tooth 2 face the circumferential center of the yoke. The first tooth crown 101 and the second tooth crown 201 are also arranged adjacently. The first side 11 of the first tooth crown 101 and the first side 21 of the second tooth crown 201 are arranged adjacently. The structures of the first tooth crown 101 and the second tooth crown 201 are different. Taking one end face of the stator lamination as the projection plane, in the circumferential direction of the stator lamination, the first tooth crown 101 and the second tooth crown 201 are adjacent. An offset portion 4 is provided on the side adjacent to the tooth crown 201, namely the first side 11 of the first tooth crown 101. The offset portion 4 extends circumferentially to the first tooth crown 101 and extends towards the second tooth crown 201, forming a first groove 5 between the offset portion 4 of the first tooth crown 101 and the first side 21 of the second tooth crown 201. Due to the presence of the offset portion 4, the first groove 5 is biased towards the second stator tooth 2. The geometric center line of the first groove 5 is offset from the geometric center line of the stator slot 3. This center line is a line in the radial direction of the stator lamination, and the stator slot 3 and the first groove 5 are connected. An auxiliary groove 6 is provided at the end of both the first tooth crown 101 and the second tooth crown 201. The auxiliary groove 6 penetrates the tooth crown in the thickness direction of the stator lamination.

[0039] In this embodiment, since the stator slots 3 are typically evenly distributed along the circumference of the yoke, the change in air gap permeability also exhibits a strict periodicity, resulting in the cogging torque displaying obvious fundamental and harmonic components. The change in permeability, or magnetic conductivity, is due to the rotation of the magnetic poles generated by the magnets within the rotor as it rotates. When these poles pass through the stator teeth and slots 3, the difference in permeability between the stator teeth and slots causes a change in magnetic permeability. For the stator and rotor structure, the magnetic reluctance is minimum and the permeability is maximum when the poles are directly facing the stator teeth, and maximum when they are directly facing the stator slots. In traditional stator structures, stator teeth and slots are evenly distributed alternately along the stator circumference. This arrangement causes the permeability to periodically distribute according to the regular arrangement of the teeth and slots during rotor rotation, which is also a periodic change in magnetic energy. This change in magnetic energy affects the torque, thus generating cogging torque pulsations. In this embodiment, by setting an auxiliary slot 6 in the tooth crown, the frequency of magnetic reluctance change is increased, making the distribution of air gap magnetic permeability more compact. A new magnetic permeability period is introduced, generating additional harmonic components with opposite phase to the original magnetic permeability harmonics, thus reducing the amplitude of local magnetic reluctance abrupt changes. By setting an offset part 4, the center line of the first slot 5 is offset from the center line of the stator slot 3 by a certain amount, thereby making the positions of the teeth and slots non-uniformly distributed in the circumferential direction of the stator. As the rotor rotates, the magnitude of magnetic permeability changes non-periodically due to the non-uniform distribution of teeth and slots, making the magnetic permeability distribution of the entire stator lamination present a non-uniform periodicity. The magnetic permeability fluctuations of the stator slot 3 and the auxiliary slot 6 are spatially misaligned, and after superposition, a smoother equivalent magnetic permeability distribution is formed. Simultaneously, the offset section 4 and auxiliary slot 6 are set to add a spatial phase difference to the generated harmonics. The combination of auxiliary slot 6 and first slot 5 involves the superposition of magnetic permeability changes. Magnetic permeability changes due to the different permeability of magnetic poles sweeping across the tooth and slot structure. In a traditional stator, due to the uniform circumferential distribution of teeth and slots on the stator structure and the symmetrical circumferential distribution of magnetic poles in the rotor, each pair of magnetic poles will generate periodic magnetic permeability changes with the same amplitude and frequency during rotation, which are superimposed to form a larger magnetic permeability change. The setting of offset section 4 causes the peak phase of magnetic permeability change to be shifted. The offset amount of different magnetic poles is different, so that the magnetic permeability change is destroyed globally. The auxiliary slot increases the low amplitude and multi-peak magnetic permeability change, which is superimposed on the global change. From local to global, it destroys the strict periodicity of magnetic permeability change, so that the fundamental component of tooth and slot torque is decomposed into multiple high-frequency components with lower amplitude. The overall characteristics are wide-bandwidth and low-amplitude, reducing the harmonic amplitude, thereby weakening tooth and slot torque and reducing electromagnetic vibration and noise.

[0040] See also Figures 1 to 3 As shown, first stator teeth 1 are respectively provided on both sides of the second stator tooth 2. A second groove 7 is formed between the second side 22 of the second tooth crown 201 and the second side 12 of the first tooth crown 101. The center line of the second groove 7 coincides with the center line of the corresponding stator groove 3.

[0041] Specifically, since the first stator tooth 1 has an offset portion 4 on its first side, the structures of the first stator tooth 1 and the second stator tooth 2 are different. However, in this embodiment, the preferred method is to set the offset portion 4 only on the first side 11 of the first tooth crown 101, and not on the second side 12 of the first tooth crown 101. The second side 22 of the second tooth crown 201 is adjacent to the second side 12 of the first tooth crown 101, and the structure of the second side 22 of the second tooth crown 201 is the same as that of the second side 12 of the first tooth crown 101. This makes the center line of the second slot 7 coincide with the center line of the stator slot 3, while the center line of the first slot 5 is offset from the center line of the stator slot 3.

[0042] In this embodiment, first stator teeth 1 are respectively provided on both sides of the second stator tooth 2, so that offset type first slot 5 and coincident type second slot 7 are respectively formed on both sides of the second stator tooth 2. The offset of the first slot 5 further offsets the torque pulsation peaks of stator slot 3 and auxiliary slot 6 on the time axis. That is, stator slot 3, as the main slot, has its torque peak when the rotor magnetic pole is aligned with the main slot, while the peak of auxiliary slot 6 occurs when the magnetic pole is aligned with the auxiliary slot 6. When the rotor rotates, the magnetic pole sweeps through stator slot 3 and auxiliary slot 6 in sequence, and the peaks occur at different times and are offset from each other. When the rotor rotates, the peaks of the first slot 5 and the second slot 7 will not appear at the same time. After superposition, the overall pulsation amplitude is weakened. The offset of the first slot 5 is equivalent to adding a spatial phase difference to the harmonics generated by the auxiliary slot 6. The combination of the two can cover a wider range of harmonic orders, which can change the harmonic distribution of cogging torque, so that harmonics of different orders cancel each other out, thereby effectively reducing the amplitude of cogging torque. Harmonic components of cogging torque can cause torque pulsation, which in turn can lead to motor vibration and noise. By weakening these harmonic components, torque pulsation can be reduced, motor operation can be improved, and noise can be reduced.

[0043] In one specific implementation, the second side 12 of the first crown 101 and the second side 22 of the second crown 201 have the same structure, which can ensure that the center line of the second slot 7 coincides with the center line of the stator slot 3. In other embodiments, the structures of the first crown 101 and the second crown 201 may be different depending on the structure of the stator slot 3, but it is still necessary to ensure that the center line of the second slot 7 coincides with the center line of the stator slot 3. The first side 11 of the first crown 101 is provided with an offset portion 4. Correspondingly, the circumferential width of the first side 21 of the second crown 201 is smaller than the circumferential width of its second side. That is, the circumferential width of the first side 21 of the first crown 101 is extended, and the circumferential width of the first side 21 of the second crown 201 is reduced, so that the center line of the first slot 5 is offset towards the second crown 201. Preferably, the center line of the first slot 5 and the center line of the stator slot 3 are set parallel to each other, that is, the two lines will not intersect, the two centers are parallel to each other, the remaining area of ​​the stator tooth tip has a strong resistance to centrifugal force, good mechanical strength, and the parallel center line has low machining accuracy and low machining difficulty. In other embodiments, the center line of the first slot 5 intersects the center line of the stator slot 3. The specific setting can be adjusted according to the structure of the first slot 5 and the stator slot 3, but it is still necessary to ensure that the center line of the first slot 5 is offset relative to the center line of the stator slot 3. Furthermore, in this embodiment, since the stator lamination simultaneously has an offset type first slot 5 and an overlapping type second slot 7, and the widths of the first slot 5 and the second slot 7 are also different, the center line of the first slot 5 is offset by setting the offset part 4. This reduces the width of the first slot 5 while achieving non-periodic magnetic permeability. By reducing the width of the first slot 5, the effective area of ​​the tooth crown is reduced, the local air gap length is reduced, the magnetic permeability amplitude is reduced, and thus the tooth cogging torque pulsation is weakened. Specifically, the width of the second slot 7 is greater than the width of the first slot 5. In other embodiments, the widths of the two slots can also be the same, or the width of the first slot 5 can be greater than the width of the second slot 7.

[0044] As a specific implementation method, stator slot type 3 is an open slot, which helps to reduce stray losses. The open slot setting avoids the formation of magnetic circuits inside the stator and improves motor output.

[0045] See also Figures 1 to 4 As shown, the stator lamination has multiple first stator teeth 1 and second stator teeth 2 arranged in the circumferential direction. The number of first stator teeth 1 is greater than the number of second stator teeth 2, and multiple first stator teeth 1 are arranged between adjacent second stator teeth 2.

[0046] In this embodiment, multiple first stator teeth 1 are arranged between adjacent second stator teeth 2. This arrangement can further optimize the magnetic field distribution, making the magnetic field of the motor more uniform at different positions, thereby reducing torque pulsation and vibration noise. At the same time, this arrangement can increase the flexibility of the slot-pole matching of the motor, so that the motor can maintain efficient operation under different working conditions.

[0047] See also Figure 4 As shown, three first stator teeth 1 are provided between adjacent second stator teeth 2.

[0048] In this embodiment, the three phase windings of the three-phase motor correspond to phases U, V, and W, respectively. The stator three-phase windings are spatially symmetrically distributed at 120° electrical angles to ensure symmetry in inductance, resistance, and flux linkage of each phase. Changes in the magnetic field will affect the three-phase current. This arrangement of the three-phase windings is to generate a rotating magnetic field in the stator space, enabling the motor rotor to operate normally. Each phase winding is spatially 120° apart. After three-phase alternating current is applied, a rotating magnetic field is generated, thereby driving the motor to rotate. Three first stator teeth 1 are arranged between adjacent second stator teeth 2, that is, a combination of three first slots 5 spaced apart by a second slot 7, to ensure that all three phases of the motor have overlapping and offset slots. When the three phases are arranged in three adjacent slots, this combination ensures that one phase in each phase arrangement is located in an overlapping first slot 5. For a combination of two first slots 5 or four first slots 5 spaced apart by a second slot 7, when the three phases are arranged in adjacent slots, it only achieves the effect of reducing one phase, and cannot achieve the effect of reducing cogging torque as in this embodiment.

[0049] See also Figure 9 As shown, three first stator teeth 1 are arranged between adjacent second stator teeth 2. Combined with the existing stator laminations without offset parts 4, the structure without offset parts 4, i.e., the slots are not offset, has a large overall harmonic fluctuation amplitude. However, this embodiment has both offset first slots 5 and overlapping second slots 7, and its overall harmonic fluctuation amplitude is much smaller than that of the stator lamination structure without offset parts 4. This further illustrates that this arrangement in this embodiment can ensure that there is one phase in each phase arrangement located in the overlapping slot, ensuring that there is one overlapping phase in each phase arrangement, producing the same magnetic reluctance change for different phases, making the magnetic circuits of each phase symmetrical, ensuring inductance balance, thereby optimizing the magnetic field distribution, reducing torque pulsation while ensuring smooth motor operation. This layout can further optimize the magnetic field distribution, making the magnetic field of the motor more uniform at different positions, thereby reducing torque pulsation and vibration noise, realizing the magnetic density offset of each phase, reducing cogging torque, increasing the magnetic reluctance of the stator assembly, and ensuring the motor torque output.

[0050] It is worth noting that the offset portion 4 in this embodiment is equivalent to extending the circumferential width of the tooth crown. If only the structure of the end of the first stator tooth 1 is changed, that is, the structure of the tooth end is changed to adjust the geometric position of the slot opening of the stator slot 3, and the distribution of the air gap magnetic field is changed, it mainly suppresses specific order harmonics, but higher order harmonics are not effectively treated. However, by setting the first slot opening 5 to optimize the main magnetic field distribution, and also setting the auxiliary slot 6, the auxiliary slot 6 disperses or cancels more harmonic components, especially higher order harmonics, by locally changing the magnetic reluctance. It has stronger adaptability and can stably reduce torque pulsation over a wide range of speeds and loads.

[0051] In one specific implementation, when three first stator teeth 1 are provided between adjacent second stator teeth 2, the structure of the stator slot 3 formed between the two first stator teeth 1 is the same, the structure of the stator slot 3 formed between the first stator teeth 1 and the second stator teeth 2 is the same, the structure of the stator slot 3 corresponding to the first slot 5 is roughly the same as the structure of the stator slot 3 corresponding to the second slot 7, and the end of the stator slot 3 facing the outer circle of the stator lamination is arc-shaped. The difference is that, since the first stator teeth 1 are provided with an offset part 4, the end structure of the stator slot 3 facing the radial center of the stator lamination is different, and the structure of the stator slot 3 is such that the end facing the outer edge of the stator lamination has a larger area and the end facing the radial center of the stator lamination has a smaller area.

[0052] See also Figures 1 to 3 As shown, the ends of the first crown 101 and the second crown 201 are each provided with two auxiliary grooves 6.

[0053] Specifically, in this embodiment, two auxiliary grooves 6 are provided at intervals at the end of the crown, and the two auxiliary grooves 6 have the same structure and size.

[0054] In this embodiment, the stator has three open slots and the stator laminations have a 27-slot structure. The addition of two auxiliary slots 6 effectively reduces cogging torque pulsation, decreases stator lamination deformation during operation, reduces the superposition effect of cogging torque, further weakens motor torque pulsation, and reduces motor vibration and noise during operation. The stator structure with auxiliary slots 6 in this embodiment, for a 27-slot stator, significantly reduces cogging torque with two auxiliary slots 6. However, adding one or three auxiliary slots 6 to the tooth crowns has no weakening effect; instead, it amplifies the cogging torque pulsation.

[0055] See also Figure 8As shown in the figure, this embodiment adopts three comparative schemes: no auxiliary slot 6, one auxiliary slot 6, and three auxiliary slots 6. It can be seen from the figure that when one auxiliary slot 6 is set, the pulsation amplitude increases, exacerbating the cogging torque pulsation, and the harmonic amplitude of the cogging torque is the largest. Even with two more auxiliary slots 6, i.e., three auxiliary slots 6, the fluctuation amplitude is still much larger than in this embodiment. However, when two auxiliary slots 6 are set in this embodiment, the harmonic amplitude of the cogging torque is significantly smaller than in the three comparative schemes, and the lines are smoother. This embodiment sets two auxiliary slots 6 on the tooth crown, which significantly reduces the pulsation amplitude and increases the pulsation frequency, resulting in better performance. Comparing the three schemes, it can be concluded that for a 27-slot stator, using two auxiliary slots can achieve a better effect in reducing cogging torque pulsation. This changes the pole-slot fit, optimizes the air gap magnetic field, and thus reduces the harmonic amplitude, thereby reducing cogging torque, electromagnetic vibration, and noise.

[0056] See also Figures 1 to 5 As shown, in the circumferential direction of the stator lamination, the width of the first tooth crown 101 and the second tooth crown 201 is both W1, and the width of the auxiliary groove 6 is W2. The width W2 satisfies: 0.125*W1≤W2≤0.25*W1.

[0057] In this embodiment, the auxiliary slot 6 can alter the distribution of the air gap magnetic field, increasing the number of cycles of the fundamental wave of the cogging torque. This allows the cogging torque induced by the auxiliary slot 6 to compensate for the original slot cogging torque, thereby effectively reducing the total cogging torque amplitude. The width W2 of the auxiliary slot 6, within this range, can better weaken the harmonic components in the cogging torque, better optimize the magnetic field distribution, reduce torque pulsation, improve the smoothness of motor operation, and reduce noise.

[0058] See also Figure 5 As shown, in the circumferential direction of the stator lamination, the interval between the two auxiliary slots 6 is W3, and the interval W3 satisfies: 1*W2≤W3≤1.5*W2.

[0059] In this embodiment, limiting the distance W3 and width W2 averages the air gap between the stator and rotor, preventing excessive air gap from affecting motor efficiency and ensuring tooth rigidity. Based on relevant principles of motor engineering, in practical engineering, the width of the auxiliary slot 6 typically does not exceed 25% (i.e., 1 / 4) of the tooth crown width; otherwise, it may lead to insufficient mechanical strength, especially in high-speed motors where it can easily cause tooth crown breakage. An excessively wide auxiliary slot 6 can cause tooth tip magnetic flux saturation, increasing leakage flux. A width range of 1 / 8 to 1 / 4 can usually control the leakage flux increment within 5%, which is within the normal range. For low-speed motors, a tooth crown width of 1 / 6 to 1 / 4 is used, prioritizing magnetic performance; for high-speed motors, a tooth crown width of 1 / 8 to 1 / 6 is used, prioritizing mechanical strength. For conventional motors, a width of 1 to 1.5 times the slot width is used to balance harmonic suppression and strength; for high-precision servo motors, the spacing is customized through harmonic analysis to match the main harmonic wavelengths.

[0060] See also Figure 5 As shown, in the circumferential direction of the stator lamination, the distance between the groove wall of the auxiliary groove 6 near the outer wall of the tooth crown and the corresponding outer wall of the tooth crown is W4, and the distance W4 satisfies: 0.06*W1≤W4≤0.25*W1.

[0061] In this embodiment, when the auxiliary groove 6 is provided, the distance between the groove wall of the auxiliary groove 6 near the outer wall of the tooth crown and the stator tooth wall should not be too wide or too narrow. The distance W4 is within the above range, which can ensure that the stator tooth will not break due to being too close to the tooth groove wall during operation. It is worth noting that in this embodiment, although two types of stator teeth are provided, regardless of the type of stator tooth, when two auxiliary grooves 6 are provided, the distance W4 in each auxiliary groove 6 must be within the above range.

[0062] It is worth noting that the structures of the first stator tooth 1 and the second stator tooth 2 are different, but both have auxiliary grooves 6 on the tooth crown. For the two types of stator teeth, the range of distance W4 is the same. For the first stator tooth 1, the distance W4 is smaller, with a minimum of 0.06*W1. For the second stator tooth 2, the distance W4 is larger, with a maximum of 0.25*W1. The specific value can be adjusted during use.

[0063] See also Figure 5 As shown, in the radial direction of the stator lamination, the depth of the auxiliary groove 6 is H, and the depth H satisfies: 0.08*W1≤H≤0.17*W1.

[0064] In this embodiment, the depth of the auxiliary groove 6 is related to the width of the tooth crown. The depth H is within the above range, which can avoid the auxiliary groove 6 being too deep, which would cause the air gap between the stator and the rotor to be too large and reduce the back electromotive force. At the same time, it can also avoid the depth being too large, which would affect the stiffness of the stator teeth and cause the stator to deform.

[0065] It is worth noting that the width W1 is determined when the electromagnetic scheme of the motor is set, while the width W2, the spacing distance W3, and the distance W4 restrict each structure based on size correlation.

[0066] As a specific implementation, the optimal stator lamination scheme is as follows: three first stator teeth 1 are arranged between two adjacent second stator teeth 2; a first slot 5 of overlapping type is formed between the first side 11 of the first tooth crown 101 and the first side 21 of the second tooth crown 201; a second slot 7 is formed between the second side 12 of the first tooth crown 101 and the second side 22 of the second tooth crown 201; and two auxiliary slots 6 are formed at the ends of both the first tooth crown 101 and the second tooth crown 201. With this arrangement, the centerline of the auxiliary slot 6 is offset relative to the stator slot 3, and the "phase" of its magnetic permeability change is different from that of the stator slot 3, further dispersing the concentrated area of ​​magnetic reluctance change and significantly reducing torque pulsation. The auxiliary slot 6 is formed in the tooth section, introducing an additional torque pulsation component, but its amplitude is small and its position is different from that of the stator slot 3. The torque peak of the stator slot 3 occurs when the rotor magnetic pole is aligned with the stator slot 3, while the peak of the auxiliary slot 6 occurs when the magnetic pole is aligned with the auxiliary slot 6. The offset of the first slot 5 further staggers the peak torque pulsations of stator slot 3 and auxiliary slot 6 on the time axis. When the rotor rotates, the peaks of the two will not appear simultaneously, and the overall pulsation amplitude is weakened after superposition. The offset of the first slot 5 is equivalent to adding a spatial phase difference to the harmonics generated by auxiliary slot 6. The combination of the two can cover a wider range of harmonic orders, which can change the harmonic distribution of cogging torque, so that harmonics of different orders cancel each other out, thereby effectively reducing the amplitude of cogging torque.

[0067] See results Figure 10 As shown, the first scheme is a stator lamination without auxiliary slot 6 and without offset first slot 5, the second scheme is a stator lamination without auxiliary slot 6 and offset first slot 5, and the third scheme is the scheme of this embodiment. As can be seen from the figure, the harmonic fluctuation of the cogging torque in the first scheme is large, and the number of peaks in the same position is small. The harmonic fluctuation of the second scheme is reduced compared to the third scheme, but it is still higher than the scheme of this embodiment. The harmonic fluctuation amplitude of the scheme of this embodiment is small, and the number of peaks in the same position is large. That is, the fundamental component of the cogging torque is decomposed into multiple high-frequency components with lower amplitude, and the overall characteristics are wideband and low amplitude, thereby reducing the harmonic amplitude and achieving the effect of weakening the cogging torque and reducing electromagnetic vibration and noise.

[0068] See also Figure 6 and Figure 7 As shown, a stator core includes multiple stator laminations, which are the stator laminations described above. In the axial direction of the stator core, the multiple stator laminations are stacked to form multiple core units.

[0069] In this embodiment, the stator core is formed by stacking multiple stator laminations. When the stator laminations are offset by setting an offset portion 4 on the first side 11 of the first tooth crown 101 and offsetting the center line of the first slot 5 from the center line of the corresponding stator slot 3, the distribution of the air gap magnetic field can be changed, weakening the harmonic components in the cogging torque. This setting can increase the number of cycles of the fundamental wave of the cogging torque, so that the cogging torque caused by the auxiliary slot 6 can compensate for the original slot cogging torque, thereby effectively reducing the total cogging torque amplitude. The harmonic components of the cogging torque will cause torque pulsation, which in turn will cause motor vibration and noise. By weakening these harmonic components, torque pulsation can be reduced, the smoothness of motor operation can be improved, and noise can be reduced. The stacking of multiple core units makes the stator core more stable in the axial direction, and can better withstand the mechanical and electromagnetic forces generated during motor operation.

[0070] See also Figure 6 and Figure 7 As shown, the multi-segment iron core unit includes at least a first segment iron core 8 and a second segment iron core 9 stacked sequentially. Along the circumferential direction of the stator iron core, the offset portion 4 of the first segment iron core 8 is projected onto the second side 12 of the first tooth crown 101 of the second segment iron core 9, and the offset portion 4 of the second segment iron core 9 is projected onto the second side 12 of the first tooth crown 101 of the first segment iron core 8.

[0071] In this embodiment, the offset portions 4 of the first iron core 8 and the second iron core 9 are set differently, that is, the setting directions of the two offset portions 4 are opposite. This setting achieves the stator slots 3 being staggered, and some stator slots 3 are also staggered, increasing the frequency of cogging torque pulsation while reducing the amplitude, thereby weakening the cogging torque pulsation and reducing motor noise. In practical applications, the stator laminations can be divided into three segments according to the stacking direction and stacked. The first iron core 8 is stacked first, followed by the second iron core 9, and then the second iron core 9 is stacked again; or, the second iron core 9 is stacked first, followed by the first iron core 8, and then the second iron core 9 is stacked, so that the stator slots are staggered, thereby reducing cogging torque and thus reducing motor vibration and noise.

[0072] In one specific implementation, the offset portion 4 of the first iron core 8 extends clockwise as a whole, and the offset portion 4 of the second iron core 9 extends counterclockwise. In other embodiments, the directions of the two iron cores can also be interchanged. This stacking method can be achieved either by machining stator laminations or by flipping the second iron core 9 and stacking them.

[0073] As one specific implementation method, see [link to relevant documentation] Figure 6 and Figure 7As shown, the first section of iron core 8 and the second section of iron core 9 have the same structure. Along the axial direction of the stator iron core, the stator laminations of the first section of iron core 8 are stacked in the first direction, and the stator laminations of the second section of iron core 9 are flipped 180° and stacked in the first direction, so that the projection of the offset part 4 of the first section of iron core 8 is located on the second side 12 of the first tooth crown 101 of the second section of iron core 9. The projection of the offset part 4 of the second section of iron core 9 is located on the second side 12 of the first tooth crown 101 of the first section of iron core 8.

[0074] In this embodiment, the second iron core 9 is rotated 180°, which is equivalent to rotating to another end face, that is, vertically downward or vertically upward in the axial direction of the stator iron core. The mutual offset of the upper and lower iron core offset parts 4 is equivalent to a phase adjustment of the magnetic field distribution in the axial direction, further increasing the number of stator slots 3, making the interaction of the magnetic field more complex and uniform. This helps to further optimize the torque characteristics and efficiency of the motor, reduce electromagnetic vibration and noise, weaken the harmonic amplitude generated by the tooth and slot mating, increase the magnetic reluctance of the stator assembly, reduce stator leakage flux, thereby reducing torque reduction and motor noise, achieving the effect of increasing stator tooth slots while avoiding increasing motor processing costs.

[0075] An electric motor includes a stator core, wherein the stator core is as described above.

[0076] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0077] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model. The above are only preferred embodiments of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A stator lamination, characterized in that, include: First stator tooth (1) and second stator tooth (2); In the circumferential direction of the stator lamination, the first stator tooth (1) and the second stator tooth (2) are spaced apart, and a stator groove (3) is formed between the first stator tooth (1) and the second stator tooth (2); The first stator tooth (1) has a first crown (101), and the second stator tooth (2) has a second crown (201). An offset portion (4) is provided on the first side (11) of the first crown (101). The offset portion (4) extends toward the first side (21) of the second crown (201). A first groove (5) is formed between the offset portion (4) and the first side (21) of the second crown (201). The center line of the first groove (5) is offset relative to the center line of the stator groove (3). An auxiliary groove (6) is provided at the ends of both the first crown (101) and the second crown (201).

2. The stator lamination according to claim 1, characterized in that, The first stator tooth (1) is provided on both sides of the second stator tooth (2). A second groove (7) is formed between the second side (22) of the second tooth crown (201) and the second side (12) of the first tooth crown (101). The center line of the second groove (7) coincides with the center line of the corresponding stator groove (3).

3. The stator lamination according to claim 1, characterized in that, The stator lamination is provided with a plurality of first stator teeth (1) and second stator teeth (2) in the circumferential direction. The number of first stator teeth (1) is greater than the number of second stator teeth (2), and a plurality of first stator teeth (1) are provided between adjacent second stator teeth (2).

4. The stator lamination according to claim 3, characterized in that, Three first stator teeth (1) are provided between adjacent second stator teeth (2).

5. The stator lamination according to claim 1, characterized in that, The ends of the first crown (101) and the second crown (201) are each provided with two auxiliary grooves (6).

6. The stator lamination according to claim 5, characterized in that, In the circumferential direction of the stator lamination, the width of the first tooth crown (101) and the second tooth crown (201) is W1, and the width of the auxiliary groove (6) is W2. The width W2 satisfies: 0.125*W1≤W2≤0.25*W1.

7. The stator lamination according to claim 6, characterized in that, In the circumferential direction of the stator lamination, the interval between the two auxiliary slots (6) is W3, and the interval W3 satisfies: 1*W2≤W3≤1.5*W2.

8. The stator lamination according to claim 6, characterized in that, In the circumferential direction of the stator lamination, the distance between the groove wall of the auxiliary groove (6) and the corresponding outer wall of the tooth crown is W4, and the distance W4 satisfies: 0.06*W1≤W4≤0.25*W1.

9. The stator lamination according to claim 6, characterized in that, In the radial direction of the stator lamination, the depth of the auxiliary groove (6) is H, and the depth H satisfies: 0.08*W1≤H≤0.17*W1.

10. A stator core, characterized in that, The stator includes multiple stator laminations, which are stator laminations as described in any one of claims 1 to 9. In the axial direction of the stator core, the multiple stator laminations are stacked to form multiple core units. The multiple core units include at least a first core unit (8) and a second core unit (9) stacked sequentially. Along the circumferential direction of the stator core, the offset portion (4) of the first core unit (8) is projected onto the second side (12) of the first tooth crown (101) of the second core unit (9). The offset portion (4) of the second core unit (9) is projected onto the second side (12) of the first tooth crown (101) of the first core unit (8).

11. An electric motor, characterized in that, Includes a stator core, wherein the stator core is the stator core as described in claim 10.

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