A stator structure of high slot fill factor concentrated winding

Abstract

The application discloses a high-slot-occupancy concentrated winding stator structure applied to the field related to a stator winding, adopts two kinds of split type schemes, and solves the problems that in the prior art, split type stator tooth parts need to be spliced one by one, assembly processes are many, cumulative errors are large, mechanical rigidity is low, and the last tooth winding of an integral type stator is difficult, and the slot occupancy is difficult to improve; the first kind is that at least one tooth part on a circular yoke part is arranged as an independent yoke part, the winding can be pre-wound outside the circular yoke, and then the independent yoke part is inserted into a dovetail groove along an axial direction to complete assembly, the second kind is that a notched circular yoke part and a stepped independent yoke part are overlapped and matched, magnetic flux is bypassed across a gap along the step, the distance of vertical air layer is shortened, magnetic leakage and iron loss are reduced, meanwhile, a wave-shaped elastic sheet continuously applies elastic thrust on a splicing surface, the butt joint surface is kept closely matched, splicing air gaps are stably controlled, periodic fluctuation of interface magnetic resistance is reduced, and air gap magnetic field uniformity is improved.

Description

Technical Field

[0001] This invention relates to the field of stator windings, and particularly to a stator structure with a high slot fill factor concentrated winding. Background Technology

[0002] Concentrated stator windings offer advantages such as short end lengths, low copper losses, and compact structure, making them widely used in permanent magnet motors and induction motors. Slot fill factor is a key indicator of winding performance; a high slot fill factor reduces resistance and copper losses, improving motor efficiency and power density. However, in integral stator cores, the last stator tooth cannot be wound. Therefore, to achieve a high slot fill factor, split stator cores have gradually become the mainstream solution. The core idea is to divide the stator core into independent components, wind them separately, and then assemble them to avoid the difficulty of winding in the narrow slots of an integral stator.

[0003] Several technical solutions exist for tooth-yoke separated stators. Chinese utility model patent CN220896373U discloses a modular stator and motor with high-efficiency heat dissipation. The tooth and yoke are designed separately, with the tooth connected to the yoke via dovetail slots. Coils can be directly fitted onto the tooth to improve slot fill factor. However, all teeth are independent modules that need to be assembled one by one, resulting in complex processes and affecting stiffness and concentricity. Chinese utility model patent CN201975873U discloses a split-type multi-pole stator core structure for micro wind turbines. The tooth is tenoned to the dovetail slot of the yoke via a dovetail head, but this also faces the problem of cumbersome assembly due to individual assembly. Chinese utility model patent CN223625646U discloses a fractional-slot concentrated winding stator, composed of several modules connected radially and axially. This results in more splicing interfaces and higher requirements for concentricity and stiffness.

[0004] While the existing solutions can improve the slot fill factor by separating the teeth and yoke, they generally adopt the method of separating all the teeth and splicing them one by one, which has problems such as many assembly steps, large cumulative errors, and difficulty in ensuring mechanical rigidity and concentricity. Summary of the Invention

[0005] The core of this invention lies in setting at least one tooth on the circular yoke as an independent yoke, so that the winding can be pre-wound outside the circular yoke and then the independent yoke is inserted into the dovetail slot along the axial direction to complete the assembly. This effectively solves the problems in the prior art where the split stator teeth need to be spliced ​​one by one, resulting in many assembly steps, large cumulative errors, and low mechanical stiffness, as well as the difficulty in winding the last tooth of the integral stator, which makes it difficult to improve the slot fill factor.

[0006] To solve the above problems, the present invention adopts the following technical solution.

[0007] A stator structure for a high-slot full-rate concentrated winding includes a stator yoke, which comprises a circular yoke and an independent yoke that are circumferentially joined to form a closed magnetic yoke. The inner walls of the circular yoke and the independent yoke are both fixedly connected with teeth. The inner wall of the circular yoke has multiple teeth that are evenly distributed, and the inner wall of the independent yoke has at least one tooth. The multiple teeth on the circular yoke and the independent yoke are arranged in a ring array around the central axis of the circular yoke. The upper and lower end faces of the circular yoke and the independent yoke are respectively provided with corresponding grooves, and the two opposite grooves are combined to form a complete limiting groove. A locking plate is installed in each limiting groove by bolts. The end face of the locking plate facing out of the limiting groove is flush with the end face of the circular yoke and the independent yoke. A monitoring unit is set between the two locking plates and the bottom of the limiting groove. The two monitoring units correspond to two non-adjacent corners of the independent yoke, and both correspond to the independent yoke.

[0008] Optionally, the circular yoke is a continuous ring, and the inner wall of the circular yoke is provided with a dovetail groove, with the independent yoke matching the dovetail groove.

[0009] Furthermore, the outer wall of the dovetail groove is integrally formed with an outer protrusion layer, and the distance between the outer protrusion layer and the inner wall of the dovetail groove is consistent with the thickness of the circular yoke.

[0010] Optionally, the circular yoke is a notched ring, and the notches of both the independent yoke and the circular yoke are set in a stepped shape, with the stepped structures of the two overlapping and matching each other.

[0011] Furthermore, two clearance grooves are provided on the left and right inner walls at the notch of the yoke, and wave-shaped spring pieces are placed in the clearance grooves. The crests of the wave-shaped spring pieces are pressed into contact with the ends of the independent yoke.

[0012] Optionally, the monitoring unit is a pressure sensor, and the monitoring unit is in a compressed state when the locking plate is tightened by bolts.

[0013] Optionally, a monitoring hole is provided on the locking plate. The monitoring unit includes a fixed measuring column, a moving measuring column, and a piezoelectric module disposed between the two, which are fixedly connected to the inner wall of the monitoring hole. The moving measuring column is located on the side of the fixed measuring column facing the mounting groove. When the locking plate is not installed in the mounting groove, the end of the moving measuring column protrudes outside the locking plate.

[0014] Furthermore, the dynamic measuring column includes a column body and a control ring fixedly connected between the outer wall of the column body and the inner wall of the monitoring hole. Both the fixed measuring column and the control ring are made of highly elastic materials, while the column body is a rigid structure.

[0015] Furthermore, the piezoelectric module includes a piezoelectric ceramic layer fixedly connected to the column, a base fixedly connected to the measuring column, and two electrode strips fixedly embedded in the base at one end facing the piezoelectric ceramic layer. The width of the piezoelectric ceramic layer is greater than the distance between the two electrode strips.

[0016] Furthermore, both ends of the base are arc-shaped, while the middle of the base is straight. The center of the arc is located on the upper surface of the base, and the distance between the upper and lower surfaces is less than the radius of the arc.

[0017] Compared with the prior art, the advantages of this invention are: (1) This solution sets at least one tooth on the circular yoke as an independent yoke, so that the winding can be pre-wound outside the circular yoke and then the independent yoke is inserted into the dovetail slot along the axial direction to complete the assembly. This solves the problems in the prior art where the split stator teeth need to be spliced ​​one by one, resulting in many assembly steps, large cumulative errors, low mechanical stiffness, and the difficulty in winding the last tooth of the integral stator, which makes it difficult to improve the slot fill factor.

[0018] (2) The notched circular yoke and the stepped independent yoke are joined together, and the magnetic flux detours across the gap along the step, shortening the distance of vertically passing through the air layer, reducing magnetic leakage and iron loss. At the same time, the wave spring is used to continuously apply elastic thrust on the splicing surface, so that the splicing surface is kept tightly fitted, the splicing air gap is stably controlled, the periodic fluctuation of the interface magnetic resistance is reduced, and the uniformity of the air gap magnetic field is improved.

[0019] (3) Replace the pressure sensor with a piezoelectric module. When the locking plate is loose, there is a relative displacement between the fixed measuring column and the moving measuring column, which squeezes the piezoelectric ceramic layer to generate an instantaneous voltage, thus realizing an active electrical signal warning of the loose state. The piezoelectric module has strong pressure resistance and is not easy to drift under long-term stress. It has higher monitoring sensitivity and can generate a measurable signal when the looseness is small. Compared with the traditional pressure sensor, it is more suitable for motor vibration conditions, improving monitoring reliability and maintenance timeliness. Attached Figure Description

[0020] Figure 1 This is a perspective view of the first embodiment of the present invention; Figure 2 This is an exploded view of part of the first embodiment of the present invention; Figure 3 This is a perspective view of the second embodiment of the present invention; Figure 4 This is an exploded view of part of the second embodiment of the present invention; Figure 5 for Figure 4 A schematic diagram at point A in the middle; Figure 6 This is a top view of the connection between the independent yoke and the circular yoke of the present invention. Figure 7 This is a front cross-sectional view of the connection between the independent yoke and the circular yoke of the present invention; Figure 8 This is a top view of the present invention when the independent yoke and the circular yoke are integrated into one structure. Figure 9 This is a front cross-sectional view of the connection between the independent yoke and the circular yoke in the third embodiment of the present invention; Figure 10 This is a cross-sectional schematic diagram of the locking plate of the present invention; Figure 11 This is a schematic diagram of the monitoring unit of the present invention; Figure 12 This is a schematic diagram of the end face of the measuring column of the present invention; Figure 13 This is a schematic diagram of the end face of the dynamic measuring column of the present invention; Figure 14 This is a schematic diagram of the cross-sectional portion of the base of the present invention.

[0021] Explanation of the labels in the diagram: 11 Circular yoke, 12 Tooth, 13 Winding, 101 Dovetail groove, 102 Outer protrusion layer, 2 Independent yoke, 201 Groove, 202 Relief groove, 3 Locking plate, 4 Waveform spring, 5 Monitoring unit, 51 Fixed measuring column, 52 Moving measuring column, 521 Column, 522 Control position outer ring, 531 Piezoelectric ceramic layer, 532 Base, 501 Electrode strip. Detailed Implementation

[0022] The technical solutions will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0023] First implementation method: like Figures 1-2 A stator structure with high slot full-rate concentrated winding includes a stator yoke. The stator yoke includes a circular yoke 11 and an independent yoke 2 that are circumferentially joined to form a closed magnetic yoke. The inner walls of both the circular yoke 11 and the independent yoke 2 are fixedly connected with teeth 12. The inner wall of the circular yoke 11 has multiple teeth 12 evenly distributed, while the inner wall of the independent yoke 2 has at least one tooth 12. The multiple teeth 12 on the circular yoke 11 and the independent yoke 2 are arranged in a ring array around the central axis of the circular yoke 11. The independent yoke 2 and its toothed portion 12 are designed so that, during winding, the independent yoke 2 can be wound outside the circular yoke 11 first, and then inserted into the dovetail groove 101 along the axial direction of the circular yoke 11. At this time, the winding 13 can smoothly enter between the teeth 12 on both sides of the dovetail groove 101. Compared with the design where multiple teeth 12 are fixed in the complete stator annular yoke, this design effectively avoids the problem of the last tooth 12 being difficult to wind evenly and improves the slot fill factor.

[0024] The upper and lower end faces of the circular yoke 11 and the independent yoke 2, which are close to each other, are provided with corresponding grooves 201. The two opposite grooves 201 are combined to form a complete limiting groove. A locking plate 3 is installed in each limiting groove by bolts. The locking plate 3 can limit the independent yoke 2, so that the motor with the stator concentrated winding is not easy to move radially or axially due to motor vibration during use, thus effectively ensuring its stability. The end face of the locking plate 3 facing out of the limiting groove is flush with the end face of the circular yoke 11 and the independent yoke 2, so that the end of the locking plate 3 will not protrude outside the circular yoke 11, which will not easily cause an increase in axial length. At the same time, the design of the locking plate 3 embedded in the limiting groove can also prevent the independent yoke 2 from moving radially.

[0025] like Figure 7 Monitoring units 5 are installed between the two locking plates 3 and the bottom of the limiting groove. The two monitoring units 5 correspond to two non-adjacent corners of the independent yoke 2, and both correspond to the independent yoke 2. The monitoring units 5 are pressure sensors. When the locking plates 3 are tightened by bolts, the monitoring units 5 are in a compressed state. In the initial state, the bolts are well tightened, and the pressure data of the two monitoring units 5 tend to be consistent. When the locking plates 3 are loose, the data of at least one monitoring unit 5 will be significantly reduced when the motor is not working. When the motor is working, the data of at least one monitoring unit 5 will show obvious fluctuations due to vibration. Therefore, by monitoring the pressure data measured by the two monitoring units 5, it is possible to effectively monitor whether the locking plates 3 are loose, which facilitates timely maintenance by the staff and effectively reduces the impact of the split design on the stability of the stator.

[0026] like Figure 2 The circular yoke 11 is a continuous ring, and a dovetail groove 101 is formed on the inner wall of the circular yoke 11. The independent yoke 2 matches the dovetail groove 101. An outer protrusion layer 102 is integrally formed on the outer wall of the circular yoke 11 corresponding to the dovetail groove 101. The distance between the outer protrusion layer 102 and the inner wall of the dovetail groove 101 is consistent with the thickness of the circular yoke 11. The independent yoke 2 is accommodated by the opening of the dovetail groove 101, so that the entire stator yoke is a complete ring and the entire magnetic circuit is not interrupted. At the same time, the thickening design of the outer protrusion layer 102 ensures that the thickness of the stator yoke at the dovetail groove 101 is still consistent with other areas. This prevents the magnetic circuit from becoming uneven due to a sudden decrease in cross-sectional thickness at this location. The magnetic cross-sectional area of ​​the slotted area is basically the same as that of the rest of the yoke, suppressing local magnetic saturation of the yoke, balancing the magnetic flux density distribution in the circumferential direction of the annular yoke, reducing harmonic losses and torque pulsation in the splicing area, and improving the uniformity of the air gap magnetic field of the motor.

[0027] Second implementation method: like Figures 3-4The circular yoke 11 is a ring with a notch. The notches of the independent yoke 2 and the circular yoke 11 are both set in a stepped shape, and the stepped structures of the two overlap and match each other. If the end faces of the two are flat and connected, the magnetic flux will pass directly through a straight gap. However, with the design of this stepped structure, the magnetic flux needs to detour along the steps to cross the gap, which effectively shortens the distance of the magnetic flux to pass through the air layer vertically, weakens the negative impact of the high magnetic resistance of the air, reduces magnetic leakage, and reduces iron loss and torque pulsation.

[0028] In this embodiment, during winding, the multiple teeth 12 on the circular yoke 11 are wound first, and then the winding 13 wound on the teeth 12 of the independent yoke 2 is placed between the two teeth 12 at the notch. Then, the independent yoke 2 is inserted radially into the notch, and the teeth 12 pass through the winding 13. Figure 6 Finally, the circular yoke 11 and the independent yoke 2 are fastened together by locking plate 3 and bolts, which can also effectively avoid the problem that the last tooth 12 cannot be wound evenly and improve the slot fill factor.

[0029] like Figures 4-5 Two clearance grooves 202 are provided on the left and right inner walls of the notch of the circular yoke 11. A wave spring 4 is placed in the clearance groove 202. The crest of the wave spring 4 is pressed against the end of the independent yoke 2. When the independent yoke 2 is assembled and installed with the notch of the circular yoke 11, the crest of the wave spring 4 abuts against the end face of the independent yoke 2 and is in a compressed state. This results in a long-term output of elastic thrust in the circumferential direction, which keeps the splicing surfaces of the independent yoke 2 and the circular yoke 11 tightly fitted, stably controls the size of the splicing air gap, and reduces the periodic fluctuation of the interface magnetic resistance.

[0030] It is worth noting that, such as Figure 8 Alternatively, the circular yoke 11 and the independent yoke 2 can be designed as a single structure. In this case, the monitoring unit 5 and its related structures can be omitted, as detailed below: Furthermore, the axial outer wall of one of the teeth 12 on the circular yoke 11 is cut, resulting in a rectangular cross-section for the cut tooth 12. In this embodiment, one tooth 12 is arbitrarily selected, its outer wall is cut, and this tooth 12 is arranged in the last winding 13. Because the outer wall of the tooth 12 is cut, the space between the tooth 12 and the two adjacent teeth 12 increases when the last winding 13 is wound on it. This allows the last winding 13 to have sufficient space to fit over the corresponding tooth 12. In other words, multiple teeth 12 can be wound simply by cutting the axial outer wall of the tooth 12. However, since the outer wall of one tooth 12 is partially cut, it will have a certain impact on the magnetic balance of the stator. Therefore, this solution is only an alternative and is suitable for motors with relatively low performance requirements.

[0031] The third implementation method: like Figures 9-11 The locking plate 3 has a monitoring hole. The monitoring unit 5 includes a fixed measuring column 51, a moving measuring column 52, and a piezoelectric module disposed between them, all fixedly connected to the inner wall of the monitoring hole. The moving measuring column 52 is located on the side of the fixed measuring column 51 facing the mounting groove. The moving measuring column 52 includes a column body 521 and a control ring 522 fixedly connected between the outer wall of the column body 521 and the inner wall of the monitoring hole. Both the fixed measuring column 51 and the control ring 522 are made of highly elastic material, while the column body 521 is a rigid structure. When the locking plate 3 is not installed in the mounting groove, the end of the moving measuring column 52 protrudes outside the locking plate 3, so that after installation, the moving measuring column 52 is completely squeezed into the monitoring hole, thereby making it and the fixed measuring column 521... 1. Stable resistance, thus temporarily becoming one unit. When the motor vibrates during operation, the fixed measuring column 51 and the moving measuring column 52 are not prone to relative squeezing and collision. Therefore, the piezoelectric module cannot generate instantaneous voltage, or can only generate a weak instantaneous voltage. When the locking plate 3 becomes loose, the stability of the temporary integrated structure of the fixed measuring column 51 and the moving measuring column 52 decreases. When the motor vibrates, the two will generate a certain relative displacement due to the vibration force, which will cause the piezoelectric module between them to be subjected to squeezing force, thus generating instantaneous voltage. Based on this data, it can be determined whether the locking plate 3 has become loose, which is convenient for timely maintenance and reduces the impact of the separate circular yoke 11 and independent yoke 2 on the stability of the stator.

[0032] like Figures 12-14 The piezoelectric module includes a piezoelectric ceramic layer 531 fixedly connected to a column 521, a base 532 fixedly connected to a measuring column 51, and two electrode strips 501 fixedly embedded in the base 532 facing one end of the piezoelectric ceramic layer 531. The width of the piezoelectric ceramic layer 531 is greater than the distance between the two electrode strips 501, effectively ensuring stable contact between them. The left and right ends of the base 532 are arc-shaped, and the middle part of the base 532 is straight. The center of the arc is located on the upper end face of the base 532, and the distance between the upper end face and the lower end face is less than the radius of the arc. This effectively ensures that the contact between the piezoelectric ceramic layer 531 and the base 532 is mainly concentrated at the electrode strips 501, with a small contact surface, presenting a line contact. When the locking plate 3 becomes loose, the two are easily separated, improving its sensitivity to the loosening of the locking plate 3. This allows the piezoelectric module to generate an instantaneous voltage when the locking plate 3 becomes slightly loose, improving monitoring sensitivity.

[0033] Compared to the design of monitoring unit 5, the loosening monitoring method in this embodiment has stronger pressure resistance of the piezoelectric module, which is less prone to performance changes due to long-term stress, making its working time and monitoring results more accurate. In specific implementation, one method can be selected.

[0034] The above description is merely a preferred embodiment of the present invention; it encompasses all the protection scope of the present invention. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solutions and improved concepts of the present invention, should be covered within the protection scope of the present invention.

Claims

1. A stator structure with high slot fill factor concentrated winding, characterized in that: The yoke includes a circular yoke (11) and an independent yoke (2) that are joined together in the circumferential direction to form a closed magnetic yoke. The inner walls of the circular yoke (11) and the independent yoke (2) are both fixedly connected with teeth (12). There are multiple teeth (12) on the inner wall of the circular yoke (11) and they are evenly distributed. There is at least one tooth (12) on the inner wall of the independent yoke (2). The multiple teeth (12) on the circular yoke (11) and the independent yoke (2) are arranged in a ring array around the central axis of the circular yoke (11). The upper and lower end faces of the circular yoke (11) and the independent yoke (2) are provided with corresponding grooves (201), and the two opposite grooves (201) are combined to form a complete limiting groove. Each limiting groove is fitted with a locking plate (3) by bolts. The end face of the locking plate (3) facing out of the limiting groove is flush with the end face of the circular yoke (11) and the independent yoke (2). A monitoring unit (5) is provided between the two locking plates (3) and the bottom of the limiting groove. The two monitoring units (5) correspond to two non-adjacent corners of the independent yoke (2), and both correspond to the independent yoke (2).

2. The stator structure of a high slot fill factor concentrated winding according to claim 1, characterized in that: The circular yoke (11) is a continuous ring, and the inner wall of the circular yoke (11) is provided with a dovetail groove (101). The independent yoke (2) matches the dovetail groove (101).

3. The stator structure of a high slot fill factor concentrated winding according to claim 1, characterized in that: The circular yoke (11) has an integrally formed outer protrusion (102) on the outer wall of the dovetail groove (101), and the distance between the outer protrusion (102) and the inner wall of the dovetail groove (101) is consistent with the thickness of the circular yoke (11).

4. The stator structure of a high slot fill factor concentrated winding according to claim 1, characterized in that: The circular yoke (11) is a ring with a notch, and the notches of the independent yoke (2) and the circular yoke (11) are both set in a stepped shape, and the stepped structures of the two overlap and match each other.

5. The stator structure of a high slot fill factor concentrated winding according to claim 4, characterized in that: Two relief grooves (202) are provided on the left and right inner walls of the notch of the circular yoke (11). A wave spring (4) is placed in the relief groove (202), and the crest of the wave spring (4) is pressed against the end of the independent yoke (2).

6. The stator structure of a high slot fill factor concentrated winding according to claim 1, characterized in that: The monitoring unit (5) is a pressure sensor. When the locking plate (3) is tightened by bolts, the monitoring unit (5) is in a squeezed state.

7. The stator structure of a high slot fill factor concentrated winding according to claim 1, characterized in that: The locking plate (3) has a monitoring hole. The monitoring unit (5) includes a fixed measuring column (51), a moving measuring column (52) fixedly connected to the inner wall of the monitoring hole, and a piezoelectric module disposed between the two. The moving measuring column (52) is located on the side of the fixed measuring column (51) facing the mounting groove. When the locking plate (3) is not installed in the mounting groove, the end of the moving measuring column (52) protrudes out of the locking plate (3).

8. The stator structure of a high slot fill factor concentrated winding according to claim 7, characterized in that: The dynamic measuring column (52) includes a column body (521) and a control ring (522) fixedly connected between the outer wall of the column body (521) and the inner wall of the monitoring hole. The fixed measuring column (51) and the control ring (522) are both made of highly elastic materials, and the column body (521) is a rigid structure.

9. The stator structure of a high slot fill factor concentrated winding according to claim 8, characterized in that: The piezoelectric module includes a piezoelectric ceramic layer (531) fixedly connected to a column (521), a base (532) fixedly connected to a measuring column (51), and two electrode strips (501) fixedly embedded in the base (532) facing one end of the piezoelectric ceramic layer (531). The width of the piezoelectric ceramic layer (531) is greater than the distance between the two electrode strips (501).

10. The stator structure of a high slot fill factor concentrated winding according to claim 9, characterized in that: The base (532) has arc-shaped left and right ends and a straight middle section. The center of the arc is located on the upper surface of the base (532), and the distance between the upper and lower surfaces is less than the radius of the arc.

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