Tooth tip cap for motor stator
By inserting tooth tips into the stator slots of the motor to close the radial slot openings, the efficiency and noise problems in the radial insertion design are solved, enabling more efficient and stable motor assembly and operation.
Patent Information
- Application Number
- CN202510452732.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-04-11
- Filing Date
- 2025-04-11
- Publication Date
- 2025-10-21
AI Technical Summary
Existing radial insertion design motor stators have large radial slot openings, which leads to reduced efficiency and performance, as well as complex assembly and increased noise.
The toothed cap structure is adopted. By inserting the toothed cap into the stator slot, the radial slot opening is partially closed, reducing eddy current loss. It is also kept in place by the support legs and retaining tabs to prevent loosening.
It improves the efficiency and performance of the motor, simplifies the assembly process, reduces noise, and enhances the structural stability of the stator.
Smart Images
Figure CN120824946A_ABST
Abstract
Description
[0001] Related applications
[0002] This application claims the benefit of priority to U.S. Provisional Application Serial No. 63 / 632,807, filed April 11, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field
[0003] Exemplary embodiments relate to the field of electric machines, and more particularly to electric machines incorporating radially inserted continuous wire windings. Background Art
[0004] An electric machine is a machine that uses electromagnetic force to operate, such as a motor, generator, and similar machines. A typical electric machine consists of a stator and a rotor. The stator contains multiple windings, which are housed in slots within the stator.
[0005] In a hairpin stator, U-shaped hairpin windings are inserted axially into slots, and the opposite ends of the windings are twisted and welded together to form a composite winding. This design is advantageous in that axial insertion allows the laminations to be stamped with semi-enclosed slot openings at the lamination teeth and the inner dimension (ID) of the slots. Semi-enclosed slot openings offer advantages in terms of efficiency, performance, and noise. The windings in a hairpin stator require extensive twisting and welding to properly assemble the stator. Consequently, stator assembly is time-consuming and complex.
[0006] Alternatively, the stator can be constructed with radially inserted continuous wire. In this example, the stator includes slots at the ID with slot openings facing radially inward. The slot openings are large enough to allow the wire to enter the slots from the ID. The radial insertion design reduces the amount of twisting and welding required during assembly. However, due to this radial insertion, existing radial designs result in larger slot openings along the ID, which can reduce efficiency and performance and potentially increase noise. Summary of the Invention
[0007] Embodiments of the present disclosure provide a tooth tip cap for an electric motor, comprising a first connecting portion and a second connecting portion spaced apart from the first connecting portion. A first leg and a second leg connect the first connecting portion to the second connecting portion. The tooth tip cap is configured such that each leg partially reduces an air gap between radially inserted slot windings of a stator.
[0008] Embodiments of the present disclosure further provide a stator comprising a plurality of stator teeth arranged around an inner diameter of the stator and extending radially inward. The stator comprises a plurality of winding slots, each of the plurality of winding slots being defined between two corresponding stator teeth from the plurality of stator teeth. The stator further comprises a plurality of tooth tip caps, each tooth tip cap comprising a first leg and a second leg. Each leg is disposed in a corresponding winding slot from the plurality of winding slots. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The following description should not be considered as limiting in any way. Referring to the accompanying drawings, the same reference numerals are used for the same elements:
[0010] Figure 1 depicts a tooth tip cap for installation in a radially inserted stator;
[0011] Figure 2 depicts a partial view of a stator including a tooth tip cap according to an example;
[0012] Figure 3 depicts a partial view of a stator including a tooth tip cap according to another example;
[0013] Figure 4 depicts a partial view of a stator including a tooth tip cap according to yet another example;
[0014] Figure 5 Depicts Figure 4 A stator tooth tip cap, the tooth tip cap being shown independently of the stator environment;
[0015] Figure 6 depicts a partial cross-section of the stator as viewed from an axially oriented perspective;
[0016] Figure 7 A partial view showing a tip cap configuration including a connecting bridge; and
[0017] Figure 8 A partial view of a stator including a tooth tip cap according to another example is shown. DETAILED DESCRIPTION
[0018] One or more embodiments of the disclosed apparatus and method are described in detail herein by way of example and not limitation with reference to the accompanying drawings.
[0019] To reduce operational drawbacks associated with the larger radially inward facing slot openings of stators designed for radial winding insertion, a tooth tip cap is inserted into each stator slot after the corresponding radial winding is inserted. The tooth tip cap partially closes the radially inward facing slot opening, thereby reducing the drawbacks associated with using a radial insertion stator.
[0020] Figure 1 Exemplary tip caps 100, 110, 160 are shown that can be used in radially inserted stators according to any of the designs described herein. In some stators, tip caps 100, 110, 160, or any combination thereof, can be used in a circumferentially alternating manner and / or in combination with other tip cap configurations.
[0021] Each tooth tip cap 100, 110, 160 is made of stamped or cut magnetic permeable material (e.g., steel) to reduce eddy current losses. The thickness of the tooth tip cap 100, 110, 160 in the radial direction relative to the axis of the stator in which the tooth tip cap 100, 110, 160 is installed ranges from approximately 0.2 mm to 0.5 mm. The tooth tip cap 100 can be stamped from electrical lamination material. To further reduce eddy current losses, the tooth tip cap 100 can be made of high-silicon (e.g., 3.5% silicon or 6.5% silicon) electrical steel.
[0022] Each tooth tip cap 100, 110, 160 includes a connecting portion 104, 114, 164 at a first axial end 101 and a second connecting portion 106, 116, 166 at a second axial end 103 opposite the first axial end 101. The axial connecting portions 104, 106, 114, 116, 164, 166 are connected by legs 108, 118, 168. In one example, the entire tooth tip cap 100, 110, 160 is formed from a single sheet of material by stamping, cutting, or both.
[0023] In both the first example tip cap 100 and the second example tip cap 110, the legs 108, 118 are zigzag shaped, including bends 120, 123 and slots 109, 119. The inclusion of slots 109, 119 in the legs 108, 118 further reduces eddy currents.
[0024] In examples where the vortex flow associated with the tip cap 160 provides acceptable performance (eg, the tip cap 160 ), the legs 168 may be straight or contain minimal bends.
[0025] In the first example tip cap 100, legs 108 include relatively large slots 109 between bends 120. Slots 109 reduce eddy current losses caused by the inclusion of tip cap 100 at the expense of increased air gap. The large size of slots 109 allows tip cap 100 to be manufactured using stamping techniques, but requires a larger air gap.
[0026] In the second tooth tip cap 110, the legs 118 include smaller slots 119 located between bends 123. As in the first example, slots 119 reduce eddy current losses caused by the presence of the tooth tip cap. Smaller slots 119 increase the amount of tooth tip material, further enclosing radially facing winding slots. However, smaller slots 119 require a manufacturing process involving cutting and milling.
[0027] Continue to refer to Figure 1 , Figure 2 A first tooth tip cap 100 configuration is shown inserted into a stator 102. Figure 3 A second tooth tip cap 110 is shown inserted into the stator 102. In one example, the stator 102 is a laminated stator constructed from axially stacked laminations. The stator 102 includes a plurality of teeth 122 extending radially inward, with radial insertion slots 124 defined between adjacent teeth 122. During assembly, an insulating gasket 126 is installed in each slot 124. Following the gasket 126, a winding 128 is radially inserted into the slot 124, and the tooth tip caps 100, 110 are installed. Each tooth tip cap 100, 110 is positioned around the radially inner end of one tooth 122, such that the axial connection portions 104, 106, 114, 116 of the tooth tip caps 100, 110 extend beyond the axial end of the tooth 122, and each meandering connection 108, 118 is positioned within a slot 124 adjacent to the tooth 122 around which the tooth tip cap 100, 110 is positioned.
[0028] The resulting configuration includes the legs 108, 118 of each tip cap 100, 110 being positioned in two adjacent radially aligned slots 124, with each slot 124 receiving the legs 108, 118 of two tip caps 100, 110. An air gap 140 is defined between the legs 108, 118 received in each slot 124.
[0029] Continue to refer to Figure 1-Figure 3 , Figure 4 Another example of a tooth tip cap 500 is shown, which is installed in the stator 102 and held in place by axially extending retaining tabs 502. The tooth tip cap 500 may be Figure 1 In any of the tooth tip cap configurations shown (tooth tip cap 100, 110, or 160), axially extending retention tabs 502 extend from either or both axial connectors of the tooth tip cap 500. Each tooth 422 of the stator 102 includes an axially extending lip 504. The axially extending lip 504 extends axially outward from the tooth 422. When the tooth tip cap 500 is installed, the retention tabs 502 flex to pass over the axially extending lip 504 and then spring back into place once the tooth tip cap 500 is fully seated. The interaction between the axially extending retention tabs 502 and the lip 504 prevents the tooth tip cap 500 from vibrating loose from the slot, falling out of the slot due to gravity, or otherwise failing out of position.
[0030] In alternative embodiments, the retaining tabs 502 may be friction fit with the teeth 422, or may fit into corresponding holes or divots in the teeth 422 to further assist the retaining tabs 502 in retaining the tooth tip caps 500 in place. In one example, the holes or divots in the teeth 422 may be formed by including holes at corresponding locations in the teeth of one, two, or three axially outermost laminations at each axial end of the stator 100.
[0031] Continue to refer to Figure 1-Figure 5 , Figure 6 A close-up view of two slots 602 containing slot liners 606 is shown. To prevent the tooth tip cap 608 from accidentally forming a current path with the winding 610, a liner wedge 612 is positioned within each slot 602 and between the tooth tip cap 608 and the winding 610 in that slot 602. The liner wedge 612 is constructed from the same material as the liner 606 and can be inserted during the same assembly steps as the liner 606. Furthermore, each tooth 614 includes a circumferentially extending nub 616 at or near the inner diameter of the stator. The circumferential distance between the two nubs 616 of a slot is greater than the width of the winding 610 to facilitate winding installation. The nubs 616 have a radial height of approximately 0.3 mm along the radius of the stator.
[0032] exist Figure 6 In the example shown, the tooth tip cap 608 snaps radially outwardly of the protrusion 616, and the protrusion 616 holds the tooth tip cap 608 in place.
[0033] Now refer to all Figures 1-6 In some variations, eddy currents can be further reduced by stacking multiple tooth tip caps 100, 110, 160, 500 in the radial direction. In one example, one tooth tip cap 100, 110, 160, 500 can be stamped from a 0.25 mm thick laminate and installed in the stator slot 124. Figure 6 and Figure 1-Figure 5 For example, another tooth tip cap 100, 110, 160, 500 can be snapped onto the rear face of a protrusion on a laminated tooth. The second tooth tip cap 100, 110, 160, 500 is also approximately 0.25 mm thick, resulting in a composite cap thickness in the radial direction of approximately 0.5 mm. Composite thickness refers to the physical thickness of the tooth tip cap, excluding any radial spacing between the tooth tip caps on individual teeth.
[0034] exist Figure 7 In another variation shown, the tooth tip cap 100, 110, 160, 500 can be stamped or cut to have at least one bridge connecting two or more adjacent tooth tip caps 804. The bridge(s) 802 in this example provide a structural connection between two or more adjacent tooth tip caps 100, 110, 160, 500 and are as thin as possible in the axial direction while maintaining structural integrity, thereby minimizing the effect of the bridge 804 on the electrical characteristics of the tooth tip caps 100, 110, 160, 500.
[0035] exist Figure 8In yet another variation shown, each tooth tip cap 100 can be snapped into a winding slot 902 defined between two radially adjacent stator teeth 904, 906. After the winding 908 is inserted, the tooth tip cap 100 is inserted into the slot 900 so that in the assembled stator, the tooth tip cap 100 is located radially inside the winding 908. The tooth tip cap 100 is held in place within the slot 902 by a circumferentially extending lip 910 at the base of each tooth 904. Figure 8 In the example shown, the axial connection portion 106 of the tooth tip cap 100 does not extend beyond the axial ends of the stator teeth 904 , 906 .
[0036] Figure 8 The variations shown may employ any of the example tip cap configurations and utilize Figure 8 Variations of 902 may be used to construct a stator assembly that includes any combination of the exemplary tooth tip cap configurations distributed between the winding slots 902 .
[0037] To this end, the present application provides a tooth tip cap for an electric motor, comprising: a first connecting portion and a second connecting portion spaced apart from the first connecting portion; a first leg and a second leg connecting the first connecting portion to the second connecting portion; and wherein the tooth tip cap is configured so that each leg partially reduces the air gap of the radially inserted slot winding of the stator.
[0038] In one embodiment, the first leg and the second leg each include a set of slots.
[0039] In one embodiment, the tooth tip cap further includes a first retaining tab extending axially from one of the first connecting portion and the second connecting portion relative to an axis of the stator of the motor.
[0040] In one embodiment, the tooth tip cap further includes a second retention tab extending axially from the other of the first connecting portion and the second connecting portion.
[0041] In one embodiment, the first retention tab extends toward the other of the first connecting portion and the second connecting portion.
[0042] In one embodiment, the tooth tip cap is made of a single magnetic conductive material.
[0043] The present application also provides a stator, comprising: a plurality of stator teeth arranged around the inner diameter of the stator and extending radially inward; a plurality of winding slots, wherein each winding slot of the plurality of winding slots is defined between two corresponding stator teeth of the plurality of stator teeth; and a plurality of tooth tip caps, each tooth tip cap comprising a first leg and a second leg, each leg being disposed in a corresponding winding slot of the plurality of winding slots.
[0044] In one embodiment, the first leg of each tooth tip cap is disposed in a different corresponding winding slot than the second leg of the tooth tip cap.
[0045] In one embodiment, each tooth tip cap includes a first connecting portion and a second connecting portion separated by the first leg and the second leg.
[0046] In one embodiment, the first leg and the second leg each include a set of slots.
[0047] In one embodiment, the stator further comprises a first retaining tab extending axially from one of the first connecting portion and the second connecting portion relative to an axis of the stator.
[0048] In one embodiment, the stator further comprises a second retaining tab extending axially from the other of the first connecting portion and the second connecting portion.
[0049] In one embodiment, the first retention tab extends toward the other of the first connecting portion and the second connecting portion.
[0050] In one embodiment, the first retention tab is received in an intrusion in a stator tooth about which the tooth tip cap is disposed.
[0051] In one embodiment, the stator is a laminated stator, and wherein the intrusion in the stator comprises slots in at least two axially outermost lamination layers of the laminated stator.
[0052] In one embodiment, each stator tooth includes a first protrusion extending circumferentially into a first adjacent slot at an inner diameter of the stator tooth and a second protrusion extending circumferentially into a second adjacent slot at the inner diameter of the stator tooth.
[0053] In one embodiment, the tooth tip cap is disposed radially outside the first protrusion and the second protrusion.
[0054] In one embodiment, each winding slot includes an insulating slot liner, a rotor winding, and a liner wedge radially disposed between the rotor winding and each tooth tip cap disposed about the stator tooth defining the slot.
[0055] In one embodiment, the stator further comprises a second tooth tip cap disposed around the stator teeth.
[0056] In one embodiment, each tooth tip cap further comprises a connecting bridge structurally connecting the tooth tip cap to at least one circumferentially adjacent tooth tip cap.
[0057] In one embodiment, the tooth tip cap is formed of a magnetic conductive material.
[0058] In one embodiment, the tooth tip cap is formed from electrical steel laminate material.
[0059] In one embodiment, the tooth tip cap is formed of high silicon electrical laminate material.
[0060] In one embodiment, the tooth tip cap is formed from an electrical laminate material having at least 4% silicon.
[0061] The term "about" is intended to encompass the degree of error associated with measuring the particular quantity based on the equipment available at the time this application was filed. For example, "about" encompasses a range of ±8% of a given value.
[0062] The terms used herein are intended only to describe specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be further understood that the terms "comprises" and "includes," when used in this specification, specify the presence of the recited features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.
[0063] Although the present invention has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. Furthermore, many modifications may be made to adapt a particular situation or material to the teachings of the present invention without departing from its essential scope. Therefore, the present invention is not limited to the specific embodiments disclosed as the best mode for carrying out the invention, but is intended to encompass all embodiments falling within the scope of the claims.
Claims
1. A tooth tip cap for a motor, the tooth tip cap comprising: a first connecting portion and a second connecting portion spaced apart from the first connecting portion; a first leg and a second leg connecting the first connecting portion to the second connecting portion; and The tooth tip cap is configured such that each leg partially reduces the air gap of the radially inserted slot winding of the stator.
2. The tooth tip cap of claim 1, wherein the first leg and the second leg each include a set of slots. 3 . The tooth tip cap of claim 1 , further comprising a first retaining tab extending axially from one of the first connecting portion and the second connecting portion relative to an axis of the stator of the motor. 4 . The tooth tip cap of claim 3 , further comprising a second retention tab extending axially from the other of the first connecting portion and the second connecting portion.
5. The tooth tip cap of claim 3, wherein the first retaining tab extends toward the other of the first connecting portion and the second connecting portion. The tooth tip cap according to claim 1 , wherein the tooth tip cap is made of a single magnetic conductive material.
7. A stator, comprising: a plurality of stator teeth arranged about an inner diameter of the stator and extending radially inwardly; a plurality of winding slots, wherein each winding slot of the plurality of winding slots is defined between two corresponding stator teeth of the plurality of stator teeth; as well as A plurality of tooth tip caps, each tooth tip cap including a first leg and a second leg, each leg disposed in a corresponding winding slot of the plurality of winding slots.
8. The stator of claim 7, wherein a first leg of each tooth tip cap is disposed in a different corresponding winding slot than a second leg of the tooth tip cap.
9. The stator of claim 7, wherein each tooth tip cap includes a first connecting portion and a second connecting portion spaced apart by the first leg and the second leg.
10. The stator of claim 9, wherein the first leg and the second leg each include a set of slots.
11. The stator of claim 9, further comprising a first retention tab extending axially from one of the first connection portion and the second connection portion relative to an axis of the stator. 12 . The stator of claim 11 , further comprising a second retention tab extending axially from the other of the first connection portion and the second connection portion. 13 . The stator of claim 11 , wherein the first retaining tab extends toward the other of the first connecting portion and the second connecting portion.
14. The stator of claim 11, wherein the first retention tab is received in an intrusion in a stator tooth about which the tooth tip cap is disposed.
15. The stator of claim 14, wherein the stator is a laminated stator, and wherein the intrusion in the stator comprises slots in at least two axially outermost lamination layers of the laminated stator.
16. The stator of claim 7, wherein each stator tooth includes a first protrusion extending circumferentially into a first adjacent slot at an inner diameter of the stator tooth and a second protrusion extending circumferentially into a second adjacent slot at the inner diameter of the stator tooth. 17 . The stator of claim 16 , wherein the tooth tip cap is disposed radially outside the first protrusion and the second protrusion.
18. The stator of claim 7, wherein each winding slot comprises an insulating slot liner, a rotor winding, and a liner wedge radially disposed between the rotor winding and each tooth tip cap disposed about the stator tooth defining the slot.
19. The stator of claim 7, further comprising a second tooth tip cap disposed around the stator teeth.
20. The stator of claim 7, wherein each tooth tip cap further comprises a connecting bridge that structurally connects the tooth tip cap to at least one circumferentially adjacent tooth tip cap.
21. The stator of claim 7, wherein the tooth tip caps are formed of a magnetically conductive material.
22. The stator of claim 21, wherein the tooth tip caps are formed from electrical steel lamination material.
23. The stator of claim 22, wherein the tooth tip caps are formed from high silicon electrical lamination material.
24. The stator of claim 23, wherein the tooth tip cap is formed from an electrical lamination material that is at least 4% silicon.