Stator punching sheet, stator core and motor

Abstract

The invention 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. 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 damaged from local to global, and harmonic amplitude is reduced so as to weaken cogging torque.

Description

Technical Field

[0001] The invention belongs to the technical field of motors, and in particular relates to a stator punching sheet, a stator core and a motor. Background Art

[0002] In a permanent magnet motor, the stator core is an important part of the motor magnetic circuit. The existing stator slot shape generally adopts a half-open slot, and the stator slots are evenly distributed on the stator core in the circumferential direction. Since the stator has a structure of teeth and slots, when the rotor rotates, the stator teeth and the rotor teeth are aligned and staggered, which will cause a change in torque. This periodic change in magnetic flux causes torque pulsation, which will produce a large cogging torque. The change in the stator cogging torque is one of the main reasons for the electromagnetic vibration and noise of the motor. The cogging torque changes with the relative position of the stator and the rotor. The conventional stator slots are evenly distributed along the circumference. The change in air gap permeability has strict periodicity, resulting in obvious fundamental and harmonic components of the cogging torque. The stator tooth harmonics are low in number and large in amplitude, resulting in large cogging torque pulsation. The large cogging torque pulsation is superimposed on the electromagnetic torque of the motor, further causing electromagnetic torque pulsation, affecting the control accuracy of the motor. The pulsating torque will cause mechanical vibration of the motor stator and rotor, affecting the running stability of the motor, and will also be transmitted through the structure, causing vibration of the motor housing and generating noise. Summary of the invention

[0003] The present invention provides a stator punching sheet, a stator core and a motor, which can solve the technical problem that the air gap magnetic permeability change of the existing stator core structure has strict periodicity, the tooth slot torque presents obvious fundamental and harmonic components, the stator tooth harmonic order is low and the amplitude is large, resulting in large tooth slot torque pulsation.

[0004] The present invention provides a stator punching sheet, which includes a first stator tooth and a second stator tooth;

[0005] In the circumferential direction of the stator punching sheet, the first stator teeth and the second stator teeth are arranged at intervals, and a stator slot is formed between the first stator teeth and the second stator teeth;

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

[0007] In some embodiments, the first stator teeth are respectively disposed on both sides of the second stator tooth, a second notch is formed between the second side of the second tooth crown and the second side of the first tooth crown, and a center line of the second notch coincides with a center line of the corresponding stator slot.

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

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

[0010] In some embodiments, two auxiliary grooves are formed at the ends of the first tooth crown and the second tooth crown.

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

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

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

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

[0015] A stator core comprises a plurality of stator punching sheets, wherein the stator punching sheets are the above-mentioned stator punching sheets, and in the axial direction of the stator core, the plurality of stator punching sheets are stacked into a multi-section core unit.

[0016] In some embodiments, the multiple-segment core unit includes at least a first core segment and a second core segment stacked in sequence, and along the circumferential direction of the stator core, the offset portion of the first core segment is projected on the second side of the first tooth crown of the second core segment, and the offset portion of the second core segment is projected on the second side of the first tooth crown of the first core segment.

[0017] In some embodiments, the first section of the core and the second section of the core have the same structure, and along the axial direction of the stator core, the stator punchings of the first section of the core are stacked in a first direction, and the stator punchings of the second section of the core are flipped 180° and stacked in the first direction, so that the offset portion of the first section of the core is projected on the second side of the first tooth crown of the second section of the core, and the offset portion of the second section of the core is projected on the second side of the first tooth crown of the first section of the core.

[0018] A motor comprises a stator core, wherein the stator core is the stator core mentioned above.

[0019] The present invention provides a stator punching sheet, a stator core and a motor, which have the following beneficial effects:

[0020] The present invention increases the frequency of magnetic resistance change by setting auxiliary notches on the tooth crown, makes the distribution of air gap magnetic permeance more dense, introduces a new magnetic permeance period to generate additional harmonic components with opposite phase to the original magnetic permeance harmonics, and reduces the amplitude of local magnetic resistance mutation. By setting the offset part, the magnetic permeance distribution of the entire stator punching sheet presents non-uniform periodicity, and the magnetic permeance fluctuations of the stator slot and the auxiliary slot are dislocated in space, and a smoother equivalent magnetic permeance distribution is formed after superposition. At the same time, the offset part and the auxiliary slot are set to add a spatial phase difference to the generated harmonics. The combination of the auxiliary slot and the first notch destroys the strict periodicity of the magnetic permeance change from local to global, so that the fundamental wave component of the tooth slot torque is decomposed into multiple high-frequency components with lower amplitudes, and the overall broadband and low-amplitude characteristics are presented, reducing the harmonic amplitude, so as to achieve the effect of weakening the tooth slot torque and reducing electromagnetic vibration and noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0022] Figure 1 A schematic diagram of a stator punching sheet according to an embodiment of the present invention;

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

[0024] Figure 3 is a schematic diagram of a first notch and a second notch according to an embodiment of the present invention;

[0025] Figure 4 It is a schematic diagram of an embodiment of the present invention in which three first stator teeth are arranged between adjacent second stator teeth;

[0026] Figure 5 Schematic diagram of width W1, width W2, spacing distance W3, distance W4 and depth H of an embodiment of the present invention;

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

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

[0029] Figure 8 It is a schematic diagram of the stator core cogging torque when two auxiliary slots are provided in an embodiment of the present invention;

[0030] Fig. 9 It is a schematic diagram of the cogging torque of the stator core when the first notch and the second notch are provided in an embodiment of the present invention;

[0031] Fig.10 It is a schematic diagram of the cogging torque of the stator core when the first notch and the auxiliary slot are provided according to an embodiment of the present invention.

[0032] Figures: 1-first stator tooth; 101-first tooth crown; 11-first side of the first tooth crown; 12-second side of the first tooth crown; 2-second stator tooth; 201-second tooth crown; 21-first side of the second tooth crown; 22-second side of the second tooth crown; 3-statator slot; 4-offset portion; 5-first notch; 6-auxiliary slot; 7-second notch; 8-first section of the core; 9-second section of the core. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

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

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

[0037] It is worth noting that the stator punching sheet includes a yoke and a tooth portion. The yoke is annular, and a plurality of teeth are arranged in the circumference of the yoke. The main function of the yoke is to connect the teeth into a whole to form a closed magnetic circuit. The tooth portion is a raised portion on the stator punching sheet used to fix and position the stator winding. The main function of the tooth portion is to fix and position the stator winding, and at the same time, it serves as a path for the air gap magnetic flux to pass through. The first stator tooth 1 and the second stator tooth 2 of this embodiment are tooth structures. The first stator tooth 1 and the second stator tooth 2 are arranged on the yoke, specifically on the radial 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 radial outer side of the yoke. The tooth portion specifically includes 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 a tooth crown. The tooth crown is formed by extending 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 winding. The portion on the stator punching sheet used to embed the stator winding is the slot portion, which is located between the teeth. The shape and size of the slot portion 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 tooth body of the first stator tooth 1 and the second stator tooth 2 is the slot portion.

[0038] Specifically, the stator punching sheet of the present 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 radial inner side of the yoke, and the other end of the first stator tooth 1 and the second stator tooth 2 are toward the circumferential center of the yoke, and the first tooth crown 101 and the second tooth crown 201 are also arranged adjacent to each other, and the first side 11 of the first tooth crown 101 and the first side 21 of the second tooth crown 201 are arranged adjacent to each other, wherein the structure of the first tooth crown 101 and the structure of the second tooth crown 201 are different, and one of the end faces of the stator punching sheet is used as the projection surface, in the circumferential direction of the stator punching sheet, the first tooth crown 101 and the second tooth crown 201 are arranged adjacent to each other. An offset portion 4 is provided on one side adjacent to the tooth crown 201, i.e., the first side 11 of the first tooth crown 101. The offset portion 4 is equivalent to extending the circumferential length of the first tooth crown 101, and the offset portion 4 extends toward the second tooth crown 201, so that a first notch 5 is formed 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 existence of the offset portion 4, the first notch 5 is biased toward the second stator tooth 2 as a whole. The geometric center line of the first notch 5 is offset compared to the geometric center line of the stator slot 3. The center line here is a line in the radial direction of the stator punching sheet, and the stator slot 3 is connected to the first notch 5. Auxiliary slots 6 are provided at the ends of the first tooth crown 101 and the second tooth crown 201, and the auxiliary slots 6 penetrate the tooth crown in the thickness direction of the stator punching sheet.

[0039] In this embodiment, since the conventional stator slots 3 are evenly distributed along the circumference of the yoke, the change of the air gap permeability also has strict periodicity, resulting in the cogging torque showing obvious fundamental and harmonic components, wherein the change of permeability, i.e., the change of magnetic conductivity, is due to the fact that when the rotor rotates, the magnetic poles generated by the magnetic steel in the rotor rotate accordingly. When the magnetic poles pass through the stator teeth and stator slots 3 structure of the stator, the change is caused by the different permeabilities of the stator teeth and stator slots 3. For the stator and rotor structure, the magnetic resistance is the smallest and the permeability is the largest when the magnetic poles are facing the stator teeth, and the magnetic resistance is the largest and the permeability is the smallest when facing the stator slots. In the traditional stator structure, the stator teeth and stator slots are evenly distributed alternately in the circumference of the stator. Such an arrangement makes the size of the permeability produce a periodic distribution with the regular arrangement of the teeth and slots when the rotor rotates, which is also a periodic change of magnetic energy. The change of magnetic energy affects the change of torque and thus produces cogging torque pulsation. In this embodiment, auxiliary slots 6 are provided in the tooth crown to increase the frequency of magnetic resistance change, make the distribution of air gap magnetic permeance more dense, introduce new magnetic permeance period to generate additional harmonic components with opposite phase to the original magnetic permeance harmonic, and reduce the amplitude of local magnetic resistance mutation. By providing the offset part 4, the center line of the first slot 5 and the center line of the stator slot 3 have a certain offset, so that the positions of the teeth and slots are arranged non-uniformly in the circumferential direction of the stator. As the rotor rotates, the size of the magnetic permeance changes non-periodically due to the uneven arrangement of the teeth and slots, so that the magnetic permeance distribution of the entire stator punching sheet presents non-uniform periodicity, and the magnetic permeance fluctuations of the stator slot 3 and the auxiliary slot 6 are dislocated in space, and a smoother equivalent magnetic permeance distribution is formed after superposition. The offset portion 4 and the auxiliary slot 6 are provided at the same time, and a spatial phase difference is added to the generated harmonics. The combination of the auxiliary slot 6 and the first slot 5 involves the superposition of permeance changes. The permeance will change due to the different permeance capacities when the magnetic poles sweep across the tooth slot structure. In the traditional stator, due to the uniform circumferential distribution of the teeth and slots on the stator structure, the magnetic poles are symmetrically distributed in the rotor. During rotation, each pair of magnetic poles will produce periodic permeance changes with the same amplitude and frequency, and superimpose to form a larger permeance change. The setting of the offset portion 4 causes the peak phase of the permeance change to shift, and the offset amounts of different magnetic poles are different, so that the permeance change is destroyed from the global perspective; the auxiliary slot increases the low-amplitude, multi-peak permeance change, which is superimposed on the global change, destroying the strict periodicity of the permeance change from the local to the global perspective, so that the fundamental component of the tooth slot torque is decomposed into multiple high-frequency components with lower amplitudes, presenting the characteristics of broadband and low amplitude as a whole, reducing the harmonic amplitude, so as to achieve the effect of weakening the tooth slot torque and reducing electromagnetic vibration and noise.

[0040] See also Figures 1 to 3 As shown, the first stator teeth 1 are respectively arranged on both sides of the second stator tooth 2 , and a second notch 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 , and the center line of the second notch 7 coincides with the center line of the corresponding stator slot 3 .

[0041] Specifically, since the first side of the first stator tooth 1 is provided with an offset portion 4, the structures of the first stator tooth 1 and the second stator tooth 2 are different, but the preferred manner of this embodiment is to provide the offset portion 4 only on the first side 11 of the first tooth crown 101, and the second side 12 of the first tooth crown 101 is not provided with the offset portion 4, 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 second side 22 of the second tooth crown 201 has the same structure as the second side 12 of the first tooth crown 101, so that the center line of the second notch 7 coincides with the center line of the stator slot 3, and the center line of the first notch 5 is offset from the center line of the stator slot 3.

[0042] In this embodiment, the first stator teeth 1 are respectively arranged on both sides of the second stator teeth 2, so that the first slots 5 of the offset type and the second slots 7 of the overlap type are respectively formed on both sides of the second stator teeth 2. The first slot 5 is offset to further stagger the torque pulsation peaks of the stator slot 3 and the auxiliary slot 6 on the time axis, that is, the stator slot 3 is used as the main slot, and its torque peak occurs when the rotor pole is aligned with the main slot, while the peak of the auxiliary slot 6 occurs when the pole is aligned with the auxiliary slot 6. When the rotor rotates, the poles sweep the stator slot 3 and the auxiliary slot 6 in turn, and the peaks occur at different times and staggered. When the rotor rotates, the peaks of the two will not appear at the same time, 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 the auxiliary slot 6. The combination of the first slot 5 and the second slot 7 can cover a wider range of harmonic orders, change the harmonic distribution of the cogging torque, and make the harmonics of different orders cancel each other, thereby effectively reducing the amplitude of the cogging torque. The harmonic components of the cogging torque will cause torque pulsation, which in turn causes vibration and noise in the motor. By weakening these harmonic components, the torque pulsation can be reduced, the smoothness of the motor operation can be improved, and the noise can be reduced.

[0043] As a specific implementation manner, the second side 12 of the first tooth crown 101 and the second side 22 of the second tooth 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 tooth crown 101 and the second tooth crown 201 may be different according to 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 tooth crown 101 is provided with an offset portion 4. Correspondingly, the circumferential width of the first side 21 of the second tooth crown 201 is smaller than the circumferential width of the second side thereof, that is, the circumferential width of the first side 21 of the first tooth crown 101 is extended, and the circumferential width of the first side 21 of the second tooth crown 201 is reduced, so that the center line of the first notch 5 is offset toward the second tooth crown 201. Preferably, the center line of the first notch 5 is arranged in parallel with the center line of the stator slot 3, that is, the two lines will not have an intersection, and the two centers are parallel to each other. The residual area of ​​the top of the stator tooth has a strong ability to resist centrifugal force, good mechanical strength, and the parallel center line has a low processing accuracy and a low processing difficulty. In other embodiments, the center line of the first notch 5 intersects with the center line of the stator slot 3. The specific setting can be adjusted according to the structure of the first notch 5 and the stator slot 3, but it is still necessary to ensure that the center line of the first notch 5 is offset relative to the center line of the stator slot 3. In addition, in this embodiment, since the stator punching sheet has both an offset type first slot 5 and an overlap type second slot 7, the widths of the first slot 5 and the second slot 7 are also different. By setting the offset portion 4, the center line of the first slot 5 is offset, and the width of the first slot 5 is reduced while achieving the non-periodicity of the 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, and the magnetic permeability amplitude is reduced, thereby weakening the tooth slot torque pulsation. 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 may be the same or the width of the first slot 5 may be greater than the width of the second slot 7.

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

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

[0046] In this embodiment, a plurality of first stator teeth 1 are arranged between adjacent second stator teeth 2. 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. At the same time, this arrangement can increase the slot-pole matching flexibility 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 arranged between adjacent second stator teeth 2 .

[0048] In this embodiment, the three phase windings of the three-phase motor correspond to the U phase, the V phase and the W phase respectively. The three-phase windings of the stator are symmetrically distributed at an electrical angle of 120° in space to ensure that the inductance, resistance and magnetic flux of each phase are symmetrical, and the change of the magnetic field will affect the three-phase current. The setting of this three-phase winding is to generate a rotating magnetic field in the stator space so that the motor rotor can operate normally. Each phase winding is 120° different from each other in space. After the three-phase alternating current is passed, a rotating magnetic field can be generated to drive the motor to rotate. Three first stator teeth 1 are arranged between adjacent second stator teeth 2, that is, a second notch 7 is arranged between three first notches 5 to ensure that the three phases of the motor have overlapping and offset notches. When the three phases are arranged in three adjacent notches, this combination can ensure that one phase in each phase arrangement is located in the overlapping first notch 5. For the combination of two first slots 5 or four first slots 5 with one second slot 7 between them, when the three phases are arranged in three adjacent slots, only one phase can be reduced, and the effect cannot achieve the effect of reducing the cogging torque as in the present embodiment.

[0049] See also Fig. 9 As shown, three first stator teeth 1 are arranged between adjacent second stator teeth 2. Combined with the existing stator punching sheet without the offset portion 4, the arrangement without the offset portion 4, that is, the structure without the slot offset, has a large overall harmonic fluctuation amplitude. The present embodiment is provided with both the offset type first slot 5 and the overlapping type second slot 7, and its overall harmonic fluctuation amplitude is much smaller than the stator punching sheet structure without the offset portion 4. It further illustrates that this arrangement of the present embodiment can ensure that one phase in each phase arrangement is located in the overlapping type slot, and that one phase in each phase arrangement is overlapping, and the same magnetic resistance change is generated for different phases, so that the magnetic circuits of each phase are symmetrical and the inductance is balanced, thereby optimizing the magnetic field distribution and ensuring the smooth operation of the motor while weakening the torque pulsation. This layout can further optimize the magnetic field distribution, so that the magnetic field of the motor at different positions is more uniform, thereby reducing torque pulsation and vibration noise, realizing the magnetic flux offset of each phase, weakening the tooth slot torque, increasing the magnetic resistance of the stator assembly, and ensuring the torque output of the motor.

[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 slot geometry of the stator slot 3, the distribution of the air gap magnetic field is changed, and the specific order harmonics are mainly suppressed, and the high-order harmonics are not effectively processed. However, the first slot 5 is set to optimize the main magnetic field distribution, and the auxiliary slot 6 is also set at the same time. The auxiliary slot 6 disperses or offsets more harmonic components, especially high-order harmonics, by locally changing the magnetic resistance, and has stronger adaptability, and can stably reduce torque pulsation in a wide speed and load range.

[0051] As a specific implementation manner, when three first stator teeth 1 are arranged 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 tooth 1 and the second stator tooth 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 punching is arc-shaped. The difference is that since the first stator tooth 1 is provided with an offset portion 4, the end structure of the stator slot 3 facing the radial center of the stator punching is different, and the structure of the stator slot 3 is that the end area facing the outer edge of the stator punching is large, and the end area facing the radial center of the stator punching is small.

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

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

[0054] In this embodiment, the stator slots have three open slots, and the stator punching sheet has a 27-slot structure. The two auxiliary slots 6 can effectively weaken the cogging torque pulsation, reduce the deformation of the stator punching sheet during operation, reduce the superposition effect of the cogging torque, further weaken the motor torque pulsation, and reduce the vibration and noise of the motor during operation. The stator structure with auxiliary slots 6 set in this embodiment, for a 27-slot stator, is set to open two auxiliary slots 6, which has a significant effect of weakening the cogging torque, while opening one or three auxiliary slots 6 on the crown has no weakening effect, but instead amplifies the pulsation of the cogging torque.

[0055] See also Figure 8As shown, this embodiment adopts three control schemes, namely, no auxiliary slot 6, one auxiliary slot 6 and three auxiliary slots 6. It can be concluded from the figure that when one auxiliary slot 6 is set, the setting of one auxiliary slot 6 will increase the pulsation amplitude, aggravate the cogging torque pulsation, and the harmonic amplitude of the cogging torque is the largest. Even if two more auxiliary slots 6, that is, three auxiliary slots 6, are set, the fluctuation amplitude is still large compared with this embodiment. When two auxiliary slots 6 are set in this embodiment, the harmonic amplitude of the cogging torque is obviously much smaller than those of the three control schemes, and the line is smoother. This embodiment sets two auxiliary slots 6 in the tooth crown, and the setting of two auxiliary slots 6 significantly weakens the pulsation amplitude and increases the pulsation frequency, with a better effect. By comparing the three schemes, it is concluded that for a 27-slot stator, the selection of two auxiliary slots can achieve a better effect of weakening the cogging torque pulsation, change the pole slot matching, optimize the air gap magnetic field, and then reduce the harmonic amplitude, so as to achieve the effect of weakening the cogging torque and reducing electromagnetic vibration and noise.

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

[0057] In this embodiment, the auxiliary slot 6 can change the distribution of the air gap magnetic field, increase the number of cycles of the fundamental wave of the cogging torque, and make the cogging torque caused by the auxiliary slot 6 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 stability of motor operation and reduce noise.

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

[0059] In this embodiment, the distance W3 and the width W2 are limited, which can average the air gap between the stator and the rotor, avoid the air gap being too large to affect the motor efficiency, and ensure the stiffness of the tooth. According to the relevant principles of motor science, in actual engineering, the width of the auxiliary slot 6 usually does not exceed 25% (i.e. 1 / 4) of the crown width, otherwise it may lead to insufficient mechanical strength, especially in high-speed motors, which may easily cause the crown to break. A width of the auxiliary slot 6 that is too large will lead to saturation of the top magnetic flux and increase the leakage flux. The 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 crown width of 1 / 6 to 1 / 4 is used (focusing on magnetic properties); for high-speed motors, a crown width of 1 / 8 to 1 / 6 is used (focusing on mechanical strength). For conventional motors, 1 to 1.5 times the slot width is used (taking into account harmonic suppression and strength); for high-precision servo motors, the spacing is customized through harmonic analysis (matching the main harmonic wavelength).

[0060] See also Figure 5 As shown, in the circumferential direction of the stator punching sheet, the distance between the slot wall of the auxiliary slot 6 close to 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 the present embodiment, when the auxiliary slot 6 is provided, the distance between the slot wall of the auxiliary slot 6 close to the outer wall of the tooth crown and the stator tooth wall cannot be too wide or too narrow. The distance W4 is within the above range, which can ensure that the stator tooth will not be too close to the slot wall and break during operation. It is worth noting that in the present embodiment, although two types of stator teeth are provided, no matter which type of stator teeth is provided, when two auxiliary slots 6 are provided, the distance W4 in each auxiliary slot 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 crowns. For the two stator teeth, the value range of the distance W4 is the same. For the first stator tooth 1, the value of the distance W4 is smaller, with a minimum of 0.06*W1. For the second stator tooth 2, the value of 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 sheet, the depth of the auxiliary slot 6 is H, and the depth H satisfies: 0.08*W1≤H≤0.17*W1.

[0064] In this embodiment, the depth of the auxiliary slot 6 is related to the width of the tooth crown. When the depth H is within the above range, it is possible to avoid the auxiliary slot 6 being too deep, which may lead to an excessive air gap between the stator and the rotor and reduce the back electromotive force, and at the same time avoid the depth being too large, which may affect the stiffness of the stator teeth and cause deformation of the stator.

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

[0066] As a specific implementation, the optimal solution for the stator punching sheet is that three first stator teeth 1 are arranged between two adjacent second stator teeth 2, a first notch 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 notch 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 provided at the ends of the first tooth crown 101 and the second tooth crown 201. Through this arrangement, the center line of the auxiliary slot 6 is offset compared with the stator slot 3, and the "phase" of its magnetic permeability change is different from that of the stator slot 3, which further disperses the concentrated area of ​​magnetic resistance change and has a significant effect of weakening torque pulsation. The auxiliary slot 6 is provided in the tooth part, introducing an additional torque pulsation component, but its amplitude is small and the position is different from that of the stator slot 3. The torque peak of the stator slot 3 appears when the rotor pole is aligned with the stator slot 3, while the peak of the auxiliary slot 6 appears when the pole is aligned with the auxiliary slot 6. The offset of the first slot 5 further causes the torque pulsation peaks of the stator slot 3 and the auxiliary slot 6 to be staggered on the time axis. When the rotor rotates, the peaks of the two will not appear at the same time, 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 the auxiliary slot 6. The combination of the two can cover a wider range of harmonic orders, change the harmonic distribution of the cogging torque, and make harmonics of different orders cancel each other, thereby effectively reducing the amplitude of the cogging torque.

[0067] Results Fig.10 As shown, the first scheme is a stator punching sheet without auxiliary slots 6 and without offset first slots 5, the second scheme is a stator punching sheet without auxiliary slots 6 and with offset first slots 5, and the third scheme is the scheme of this embodiment. It can be seen from the figure that the harmonic fluctuation of the tooth slot torque of the first scheme is large, and the number of occurrences of each peak in the same position is small. The degree of harmonic fluctuation of the second scheme is reduced compared with the second scheme, but it is still high compared with 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 tooth slot torque is decomposed into multiple high-frequency components with lower amplitudes, and the overall characteristics of broadband and low amplitude are presented, thereby reducing the harmonic amplitude, so as to achieve the effect of weakening the tooth slot torque and reducing electromagnetic vibration and noise.

[0068] See also Figure 6 and Figure 7 As shown, a stator core comprises a plurality of stator punching sheets, wherein the stator punching sheets are the above-mentioned stator punching sheets, and in the axial direction of the stator core, the plurality of stator punching sheets are stacked into a multi-section core unit.

[0069] In this embodiment, the stator core is formed by stacking a plurality of stator punching sheets. When the stator punching sheets are provided with an offset portion 4 on the first side 11 of the first tooth crown 101 and the center line of the first slot 5 is offset from the center line of the corresponding stator slot 3, the distribution of the air gap magnetic field can be changed, and the harmonic components in the cogging torque can be weakened. This arrangement 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 can cause torque pulsation, which in turn causes vibration and noise of the motor. By weakening these harmonic components, the torque pulsation can be reduced, the stability of the motor operation can be improved, and the noise can be reduced. The stacking of multiple-segment core units makes the stator core more stable in the axial direction, and can better withstand the mechanical and electromagnetic forces generated when the motor is running.

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

[0071] In this embodiment, the offset portion 4 of the first section of the core 8 and the second section of the core 9 are set differently, that is, the setting directions of the two offset portions 4 are opposite. Through this setting, the stator slots 3 are staggered with each other, and some stator slots 3 are also staggered, which increases the frequency of the tooth slot torque pulsation and reduces the amplitude, thereby achieving the effect of weakening the tooth slot torque pulsation, thereby reducing the motor noise. In practical applications, the stator punching sheets can be divided into three sections according to the stacking direction for stacking. After the first section of the core 8 is stacked, the second section of the core 9 is stacked, and then the second section of the core 9 is stacked; or, after the second section of the core 9 is stacked, the first section of the core 8 is stacked, and then the second section of the core 9 is stacked, so that the stator teeth are staggered, thereby reducing the tooth slot torque and thus reducing the vibration noise of the motor.

[0072] As a specific implementation, the offset portion 4 of the first section of the core 8 extends clockwise as a whole, and the offset portion 4 of the second section of the core 9 extends counterclockwise. In other embodiments, the directions of the two cores can also be interchanged. This stacking method can be achieved by machining the stator punching sheets or by turning the second section of the core 9 over and stacking it.

[0073] As a specific implementation method, refer to Figure 6 and Figure 7As shown, the first section core 8 and the second section core 9 have the same structure. Along the axial direction of the stator core, the stator punchings of the first section core 8 are stacked in the first direction, and the stator punchings of the second section core 9 are flipped 180° and stacked in the first direction, so that the offset portion 4 of the first section core 8 is projected on the second side 12 of the first tooth crown 101 of the second section core 9, and the offset portion 4 of the second section core 9 is projected on the second side 12 of the first tooth crown 101 of the first section core 8.

[0074] In this embodiment, the second section of the core 9 is flipped 180°, which is equivalent to flipping to the other end face, that is, in the axial direction of the stator core, vertically downward or vertically upward, the mutual staggering of the upper and lower core offset portions 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 fields more complex and uniform, which 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 slot matching, increase the magnetic resistance of the stator assembly, reduce stator leakage, and thus reduce torque reduction, reduce motor noise, and achieve the effect of increasing the stator tooth slot while avoiding increasing the motor processing cost.

[0075] A motor comprises a stator core, wherein the stator core is the stator core mentioned above.

[0076] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0077] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention, and these improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A stator punching sheet, characterized in that: include: A first stator tooth (1) and a second stator tooth (2); In the circumferential direction of the stator punching sheet, the first stator teeth (1) and the second stator teeth (2) are arranged at intervals, and a stator slot (3) is formed between the first stator teeth (1) and the second stator teeth (2); The first stator tooth (1) has a first tooth crown (101), and the second stator tooth (2) has a second tooth crown (201). An offset portion (4) is provided on a first side (11) of the first tooth crown (101), and the offset portion (4) extends toward a first side (21) of the second tooth crown (201). A first notch (5) is formed between the offset portion (4) and the first side (21) of the second tooth crown (201). A center line of the first notch (5) is offset relative to a center line of the stator slot (3), and auxiliary grooves (6) are provided at the ends of the first tooth crown (101) and the second tooth crown (201).

2. The stator sheet according to claim 1, characterized in that: The first stator teeth (1) are respectively arranged on both sides of the second stator tooth (2); a second notch (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); and a center line of the second notch (7) coincides with a center line of the corresponding stator slot (3).

3. The stator sheet according to claim 1, characterized in that: A plurality of the first stator teeth (1) and the second stator teeth (2) are arranged in a circumferential direction of the stator punching sheet, the number of the first stator teeth (1) being greater than the number of the second stator teeth (2), and a plurality of the first stator teeth (1) being arranged between adjacent second stator teeth (2).

4. The stator sheet according to claim 3, characterized in that: Three of the first stator teeth (1) are arranged between adjacent second stator teeth (2).

5. The stator sheet according to claim 1, characterized in that: Two auxiliary grooves (6) are provided at the ends of the first tooth crown (101) and the second tooth crown (201).

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

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

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

9. The stator sheet according to claim 6, characterized in that: In the radial direction of the stator punching sheet, 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 invention comprises a plurality of stator punching sheets, wherein the stator punching sheets are the stator punching sheets according to any one of claims 1 to 9, and in the axial direction of the stator core, the plurality of stator punching sheets are stacked into a plurality of core units; the plurality of core units at least comprise a first core section (8) and a second core section (9) stacked in sequence, and along the circumferential direction of the stator core, the offset portion (4) of the first core section (8) is projected on the second side (12) of the first tooth crown (101) of the second core section (9), and the offset portion (4) of the second core section (9) is projected on the second side (12) of the first tooth crown (101) of the first core section (8).

11. A motor, characterized in that: It comprises a stator core, and the stator core is the stator core according to claim 10.

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