Stator structure with flat wire winding

Abstract

The utility model provides a flat wire winding stator structure. The flat wire winding stator structure comprises a stator core, flat wire windings and insulating sheets, the stator core comprises an annular yoke part, a plurality of tooth parts are arranged along the circumferential direction of the yoke part, a groove body extending along the radial direction is formed between a pair of adjacent tooth parts, one end part of the pair of tooth parts is provided with a boot part extending along the circumferential direction, and a groove opening of the groove body is formed. The flat wire winding is a linear conductor and is provided with an extension section positioned in the groove body. The insulating sheet is installed in the groove body and used for wrapping the arranged extension sections. The groove body is provided with a pair of inner check blocks, the protruding direction of the inner check blocks is perpendicular to the radial direction, and the extending sections are limited between the inner check blocks and the groove bottom of the groove body.

Description

Technical Field

[0001] The present application relates to a stator structure, and more particularly to a stator structure used for flat wire windings. Background Art

[0002] The basic structure of a motor includes a stator and a rotor. Through the principle of electromagnetic induction, it converts electrical energy into rotational kinetic energy to provide torque output. The interaction between the stator and the rotating magnetic field determines the output efficiency of the motor.

[0003] The stator core structure consists of an annular yoke with multiple teeth arranged circumferentially along the yoke. A radially extending slot is formed between each pair of teeth. The ends of these teeth have a shoe extending circumferentially to form the slot opening. The shoe's function is to collect magnetic force. The wider the shoe's circumferential extension, the greater the magnetic flux the stator core can absorb. Therefore, the shoe forming the slot opening is often narrow and flat, making it relatively fragile.

[0004] The stator windings of three-phase induction motors often utilize a type of copper wire known as hairpin windings, forming a flat-wire winding. Compared to traditional windings with round cross-sections, flat-wire windings (also known as rectangular wire) not only increase the slot fill rate and allow for higher currents, but also offer better heat dissipation, enabling the motor to operate at high power density and efficiency.

[0005] To assemble a hairpin winding, multiple flat copper wires are first bent sequentially into hairpin conductors. Next, according to the winding layout, the hairpin conductors are stacked radially and arranged circumferentially into a ring. The open ends of the conductors are then inserted axially into the stator core slots. The open ends of the hairpins are then twisted, flattened, and welded to form the flat wire winding. After the formed hairpin conductors are inserted into the stator core, the copper material properties and the geometric tolerances during the bending and twisting process cause the conductors within the slots to expand radially along the core.

[0006] Furthermore, to ensure proper insulation within the stator core slots, after the flat wire windings are formed, insulating varnish is injected into the slots. This fills the gaps within the slots and prevents the wires from shifting within them, which could lead to wear and tear on the enameled wires and compromised insulation. However, due to the volume expansion of insulating varnish as it cures, it can cause displacement or deformation of the wires, even causing hairpins near the core's inner diameter to protrude from the slot openings. If the rotor is placed within the core during operation under these conditions, it can easily come into contact with the wires, potentially damaging the stator and increasing product defects. Utility Model Content

[0007] The technical problem to be solved by this application is to provide a flat wire winding stator structure, including a stator core, a flat wire winding, and an insulating sheet. The stator core includes an annular yoke portion, and a plurality of tooth portions are arranged along the circumferential direction of the yoke portion. A groove body extending along a radial direction is formed between a pair of adjacent tooth portions, and one end portion of the pair of tooth portions has a boot portion extending along the circumferential direction and forming a groove opening of the groove body. The flat wire winding includes a plurality of linear conductors, and the linear conductors have an extension section positioned in the groove body. The insulating sheet covers the sequentially arranged extension sections, and the insulating sheet is installed in the groove body and is located between the extension section and the surface of the groove body.

[0008] Wherein, a pair of inner stoppers are provided in the groove body, and the protruding direction of the inner stoppers is perpendicular to the radial direction, and the extension section is restricted between the inner stoppers and a groove bottom of the groove body.

[0009] Wherein, in a direction perpendicular to the radial direction, let the width of the groove body be Sw, the width of the opening of the groove body be G1, the width of the extension section be Lw, the thickness of the insulating sheet be It, and the spacing width between a pair of the inner stoppers be G2, then the following conditions are satisfied:

[0010] G1≦G2<Lw, and It + 0.2mm < 0.5×(Sw - G2) ≦ It + 1mm.

[0011] In the above structure, a pair of inner stoppers located in the groove body restrict a plurality of linear conductors (flat copper wires) in the groove. Therefore, when the flat copper wires are deformed by an external force, the deformation of the copper wires is constrained between the inner stoppers and the groove bottom, which can increase the manufacturing yield.

[0012] In addition, the following condition can be further satisfied, 0.1mm≦It≦0.3mm.

[0013] In addition, the insulating sheet has a main portion and two folding portions extending outward from the two sides away from the main portion. The insulating sheet is bent so that the two folding portions overlap to cover the sequentially arranged plurality of extension sections, and the two folding portions of the insulating sheet face the groove bottom.

[0014] In addition, the inner stopper has a tip and two inclined surfaces extending from the two sides away from the tip. The groove body has two groove walls extending from the two sides away from the groove bottom. In a cross-section, an extension line of each of the two inclined surfaces intersects an extension line of its adjacent groove wall to define a first point and a second point. The second point is located between the first point and the boot portion, and the extension line of the groove wall intersects the boundary of an inner circumferential surface of the stator core to define a third point;

[0015] In the cross-section, the extension section has a thickness of Lt and is parallel to the extension line of the slot wall. The distance from the first point to the second point is L3, and the distance from the second point to the third point is L4. Then, the following condition is satisfied: Lt ≤ L3 + L4. Therefore, even if the copper wire deforms within the slot, it will not protrude beyond the slot opening.

[0016] In addition, the following condition can be further satisfied: Lt≦L4.

[0017] The details of other functions and embodiments of the present application are described below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 Exploded schematic diagram of the components of the stator structure;

[0020] Figure 2 is a cross-sectional view of the stator structure;

[0021] Figure 3 for Figure 2 A partial enlarged view of

[0022] Figure 4 Schematic diagram of the structure of the stator slot;

[0023] Figure 5 for Figure 2 A partial enlarged view of

[0024] Figure 6A 、 Figure 6B 、 Figure 6C 、 Figure 6D Magnetic field distribution diagram of stator slots with different structures.

[0025] Explanation of symbols

[0026] 10: stator core 101: core unit

[0027] 11: Yoke 12: Tooth

[0028] 121: Boot 121t: Tip

[0029] 13: Flat portion 14a, 14b: Inner stopper

[0030] 14t: Tip 14p1: First point

[0031] 14p2: Second point 14s1, 14s2: Inclined surface

[0032] 15: slot body 151: slot opening

[0033] 152: groove wall 153: groove bottom

[0034] 20: Insulation sheet 21: Main part

[0035] 22A, 22B: Folded part 30: Flat wire winding

[0036] 31: Linear conductor 31A: Extension

[0037] 31B: Connecting section 51: Inner circumference

[0038] 52: Outer surface 51p3: Third point

[0039] 60: Insulation varnish filling area 70: Rotor

[0040] 71: Permanent magnet G1: Opening width

[0041] G2: Gap distance L1, L2, L3, L4: Length

[0042] Da: width direction Db: groove extension direction

[0043] It: Insulation paper thickness Lw: Wire width

[0044] Lt: conductor thickness Sw: slot width

[0045] Bd: protrusion distance DETAILED DESCRIPTION

[0046] The positional relationships described in the following embodiments include up, down, left, and right. Unless otherwise specified, they are based on the directions of the components shown in the drawings.

[0047] The motor structure of this application includes an inner rotor and an outer stator. The complete stator structure is an annular structure. In order to clearly identify each structure, only a part of the stator structure is shown in this embodiment. Figure 1 and Figure 2 , shows a part of the stator structure, which includes a stator core 10 , an insulating sheet 20 and a flat wire winding 30 .

[0048] The stator core 10 is composed of multiple core units 101 stacked axially. Each core unit 101 includes an annular yoke 11 and multiple teeth 12 arranged circumferentially around the yoke 11. A radially extending slot 15 is formed between adjacent pairs of teeth 12. One end of each pair of teeth 12 includes a shoe 121 extending circumferentially. The tips 121t of the shoe 121 are radially symmetrical and form a slot opening 151 of the slot 15. The slot 15 has a slot bottom 153 adjacent to the yoke 11 and two slot walls 152 extending away from the slot bottom 153. A portion of the shoe 121 faces the inner rotor, forming the inner circumferential surface 51 of the core unit 101. The outer circumferential surface 52 of the core unit 101 is relatively remote from the teeth 12.

[0049] The rectangular wire winding 30 includes a plurality of linear conductors 31. The shapes of the linear conductors 31 can be the same or different. Hairpin windings are used as an example of the linear conductors 31. The linear conductors 31 have a bend (not shown) and two extensions 31A extending from the bend at opposite ends. The ends of the two extensions 31A each form a connecting section 31B.

[0050] When installing the linear conductor 31, it is first folded into a U-shape (forming an extension section 31A and a bent section). The two extension sections 31A are then inserted axially into different slots 15. The bent sections of all the linear conductors 31 are located on one end of the stator core 10, while the extension sections 31A of the linear conductor 31 are located on the other end of the stator core 10. The ends of all the extension sections 31A are twisted and trimmed flat. The wires at the ends of the extension sections 31A are then exposed to form connecting sections 31B. The two corresponding connecting sections 31B are then welded together according to the wiring to form a complete circuit.

[0051] In this embodiment, the portion of the linear conductor 31 located within the slot 15 is defined as the extension 31A. During installation, deformation of the extension 31A due to external forces can increase the defect rate. Furthermore, even if the linear conductor 31 is not U-shaped, such as an I-pin, S-winding, or X-pin as defined in the prior art, as long as these conductors have an extension 31A located within the slot 15, they all fall within the definition of a linear conductor 31 in this embodiment.

[0052] The insulating sheet 20 is installed in the slot body 15 and is located between the extension section 31A and the inner surface of the slot body 15 (the slot wall 152 and the slot bottom 153). The insulating sheet 20 is constructed to cover the multiple extension sections 31A arranged in the slot body 15 to ensure insulation between the linear conductor 31 and the slot body 15.

[0053] See also Figure 2 and Figure 4 、 Figure 5 shows the contour formed by the slot 15 of the stator core 10 in the cross-section perpendicular to the axial direction of the stator core 10. A pair of inner stoppers 14a and 14b protrude from the inner surface of the slot 15, and the protruding directions of the inner stoppers 14a and 14b are perpendicular to the slot extension direction Db. When installing the flat wire winding 30, the extension section 31A is restricted between the inner stoppers 14a and 14b and the slot bottom 153.

[0054] The width direction Da of the slot 15 is perpendicular to the radial direction of the stator core 10. In the width direction Da, let the width of the slot 15 be Sw, the width of the opening of the slot 15 be G1, the extension section 31A has a width of Lw, the thickness of the insulating sheet 20 is It, and the spacing distance between the pair of inner stoppers 14a and 14b is G2. It is recommended to satisfy the following conditions:

[0055] G1 ≦ G2 < Lw, and

[0056] It + 0.2mm < 0.5×(Sw - G2) ≦ It + 1mm.

[0057] Among them, 0.5×(Sw - G2) is the protruding distance Bd of one inner stopper 14a (or inner stopper 14b) towards the inside of the slot 15 relative to the slot wall 152. The inner stoppers 14a and 14b located on different side slot walls 152 are symmetrically arranged. Under this condition, the protruding distance Bd of the inner stopper 14a towards the inside of the slot 15 is about 0.3 times to about 1 times the protruding distance of the boot part 121 towards the slot 15.

[0058] The pair of inner stoppers 14a and 14b restrict the plurality of linear conductors in the slot. When the extension section 31A is deformed by an external force, the deformation of the extension section 31A is constrained between the inner stopper and the slot bottom. When the insulating paint in the insulating paint filling area 60 in the slot 15 cures, excessive deformation can still be avoided, and the manufacturing yield can be increased.

[0059] Furthermore, the following condition can be further satisfied: 0.1mm ≦ It ≦ 0.3mm.

[0060] Furthermore, the following condition can be further satisfied: It + 0.2mm < Bd ≦ It + 0.6mm. Under this condition, the protruding distance Bd of the inner stopper 14a towards the inside of the slot 15 is about 0.4 times to about 0.6 times the protruding distance of the boot part 121 towards the slot 15.

[0061] In this embodiment, the width Sw of the slot 15 has the following condition: 3mm ≦ Sw ≦ 5mm. The width Lw of the extension section 31A has the following condition: 2.5mm ≦ Lw ≦ 4.5mm.

[0062] When the stamping process of the stator core 10 is taken into consideration, Figure 4 In the cross section shown, the inner stopper 14a has a tip 14t and two inclined surfaces 14s1 and 14s2 extending away from the tip 14t. The tips of the two inner stoppers 14a and 14b are aligned with each other and the distance therebetween is defined as a gap width G2.

[0063] In this embodiment, the centerline of the slot body 15 overlaps with the radial direction of the stator core 10 and defines the slot extension direction Db of the slot body 15. In the cross-section, the two slot walls 152 are parallel to the slot extension direction Db. An extension line of each of the two inclined surfaces 14s1 and 14s2 of each inner stopper 14a intersects with an extension line of the adjacent slot wall 152, defining a first point 14p1 and a second point 14p2. The second point 14p2 is located between the first point 14p1 and the shoe 121. The extension line of the slot wall 152 intersects the boundary of the inner circumferential surface 51 of the stator core 10, defining a third point 51p3.

[0064] In the cross section, let the extension section 31A have a thickness of Lt and be parallel to the groove extension direction Db. The distance from the groove bottom to the third point 51p3 is L1, the distance from the groove bottom 153 to the first point 14p1 is L2, the distance from the first point 14p1 to the second point 14p2 is L3, and the distance from the second point 14p2 to the third point 51p3 is L4. That is, L1, L2, L3, and L4 satisfy the following relationship:

[0065] L1=L2+L3+L4

[0066] For the purpose of this embodiment, it is recommended that the following conditions be met:

[0067] Lt≦L3+L4.

[0068] That is, the inner stoppers 14a and 14b limit the extension section 31A in the slot body 15 to a distance of the thickness Lt of the extension section 31A from the slot opening 151. Thus, even if the copper wire is deformed in the slot, it will not protrude from the slot opening.

[0069] Furthermore, the following condition can be satisfied: Lt≦L4.

[0070] In this embodiment, the thickness Lt of the extension section 31A satisfies the following condition: 1.5 mm≦Lt≦3 mm.

[0071] In this embodiment, a flat portion 13 is formed at the junction of the boot portion 121 and the inner stopper 14 a (or the inner stopper 14 b ). In the cross section, the flat portion 13 overlaps with the extension line of the groove wall 152 .

[0072] See also Figure 2 and Figure 3In this embodiment, the insulating sheet 20 has a main portion 21 and two folded portions 22A extending outward from two sides of the main portion 21. When the insulating sheet 20 is placed within the slot 15, the insulating sheet 20 bends so that the two folded portions 22A and 22B overlap, thereby covering the plurality of arranged extension segments 31A. In this embodiment, the overlapping folded portions 22A and 22B of the insulating sheet 20 face the slot bottom 153 and cover the extension segments 31A relatively close to the outer circumference 52. The main portion 21 of the insulating sheet 20 bends between the pair of inner stoppers 14a and 14b and covers the extension segments 31A relatively close to the inner circumference 51.

[0073] During stator assembly, the folded portions 22A and 22B of the insulating sheet 20 merely overlap but are not bonded. If these folded portions 22A and 22B face open space within the slot 15, they could be pushed by the multiple extensions 31A covered by the insulating sheet 20, or expand due to the insulating varnish curing. Therefore, aligning the folded portions 22A and 22B toward the slot bottom 153 and positioning the main portion 21 of the insulating sheet 20 between the extensions 31A and the inner stops 14a and 14b prevents this. Furthermore, the coordination between the insulating sheet 20's placement and the inner stops 14a and 14b ensures minimal deformation of the extensions 31A.

[0074] In a specific embodiment, the groove body 15 contains 8 extension segments 31A, G1 is 1.6 mm, G2 is 2.74 mm, Lw is 3.51 mm, Sw is 4.3 mm, It is 0.25 mm, and Bd is 0.78 mm; and Lt is 1.8 mm, L2 is 16.27 mm, L3 is 0.91 mm, and L4 is 1.85 mm.

[0075] In another specific embodiment, the groove body 15 contains 6 extension segments 31A, G1 is 1.6 mm, G2 is 3.1 mm, Lw is 3.43 mm, Sw is 4.5 mm, It is 0.2 mm, and Bd is 0.7 mm; and Lt is 2.38 mm, L2 is 16.78 mm, L3 is 0.92 mm, and L4 is 1.8 mm.

[0076] See also Figure 6A 、 Figure 6B 、 Figure 6C 、 Figure 6D These diagrams simulate the magnetic field distribution diagrams of the stator and the rotor 70 during operation, and the position of the stator is represented by the stator core 10. Figure 6A The stator core 10 does not have an inner stopper. Figure 6B The stator core 10 has an inner stopper, and a protruding distance of the inner stopper toward the inside of the slot body is about 0.5 times a protruding distance of the shoe toward the slot body. Figure 6CThe stator core 10 has an inner stopper, and a protruding distance of the inner stopper toward the inside of the slot body is approximately 1 times a protruding distance of the shoe toward the slot body. Figure 6C The two inner stopper tips of the stator core 10 are connected, that is, G2=0.

[0077] As described above, in this embodiment, the stator core 10 has an inner stopper, and when the inner stopper is within the aforementioned range, it will not affect the existing operation of the motor structure and can also have the effect of improving the process yield.

[0078] The embodiments and / or implementation methods described above are only used to illustrate the preferred embodiments and / or implementation methods for realizing the technology of the present application, and do not impose any form of limitation on the implementation methods of the technology of the present application. Any person skilled in the art may make slight changes or modifications to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present application, but they should still be regarded as technologies or embodiments that are essentially the same as those of the present application.

Claims

1. A flat wire winding stator structure, characterized in that: The flat wire-wound stator structure includes: A stator core including an annular yoke portion and a plurality of tooth portions arranged circumferentially along the yoke portion. A slot extending radially is formed between a pair of adjacent tooth portions. The ends of the pair of tooth portions have boot portions extending circumferentially and forming a slot opening of the slot. A flat wire winding including a plurality of linear conductors, and the linear conductors have extension segments positioned in the slots. Insulating sheets covering the arranged extension segments, and the insulating sheets are installed in the slots and located between the extension segments and the surfaces of the slots. It is characterized in that the slot has paired inner stoppers and the protruding directions of the inner stoppers are perpendicular to the radial direction, and the extension segments are restricted between the inner stoppers and the bottom of the slot. Wherein, in a direction perpendicular to the radial direction, let the width of the slot be Sw, the width of the opening of the slot be G1, the width of the extension segment be Lw, the thickness of the insulating sheet be It, and the interval width between a pair of the inner stoppers be G2, then the following conditions are satisfied: G1≦G2<Lw, and 2. The flat wire winding stator structure according to claim 1, characterized in that: It + 0.2mm < 0.5×(Sw - G2) ≦ It + 1mm.

3. The flat wire winding stator structure according to claim 1, characterized in that: The following condition is satisfied: 0.1mm≦It≦0.3mm.

4. The flat wire winding stator structure according to claim 1, characterized in that: The following condition is satisfied: It + 0.2mm < 0.5×(Sw - G2) ≦ It + 0.6mm.

5. The flat wire winding stator structure according to claim 1, characterized in that: A flat portion is formed at the junction of the boot portion and the inner stopper.

6. The flat wire winding stator structure according to claim 1, characterized in that: The insulating sheet has a main portion and two folding portions extending outward from the two sides away from the main portion. The insulating sheet is bent so that the two folding portions overlap to cover the arranged extension segments, and the two folding portions of the insulating sheet face the bottom of the slot. The inner stopper has a tip and two inclined surfaces extending from the two sides away from the tip, and the slot has two slot walls extending from the two sides away from the bottom of the slot. Wherein, in a cross-section, the extension lines of the two inclined surfaces respectively intersect with the extension lines of the adjacent slot walls to define a first point and a second point. The second point is located between the first point and the boot portion, and the extension line of the slot wall intersects with the boundary of the inner circumferential surface of the stator core to define a third point. Wherein, in the cross-section, let the extension segment have a thickness of Lt and be parallel to the extension line of the slot wall, the distance from the first point to the second point be L3, and the distance from the second point to the third point be L4, then the following condition is satisfied:

7. The flat wire winding stator structure according to claim 6, characterized in that: Lt≦L3 + L4.

8. The flat wire winding stator structure according to claim 1, characterized in that: The following condition is satisfied: Lt≦L4. Insulating paint is filled between the insulating sheet and the extension segment.

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