Stator of motor and method for manufacturing stator

Abstract

The present application provides a stator of a motor and a method for manufacturing a stator. The stator comprises a core (10), conductors (20), and an insulating sheet (30). A wire slot (11) is formed in the core (10). The conductors (20) and the insulating sheet (30) are inserted into the wire slot (11), and the insulating sheet (30) surrounds the conductors (20). A cooling liquid recess (12) is further formed in the core (10), and the cooling liquid recess (12) is in communication with the wire slot (11). The insulating sheet (30) comprises a framework layer (32) and an expansion layer (31). The framework layer (32) is at least arranged on the surface of the expansion layer (31) away from the conductor (20). The expansion layer (31) is not in contact with the cooling liquid recess (12). The framework layer (32) is made of an oil-resistant and high-temperature-resistant material, and the framework layer (32) is able to prevent a liquid resin from flowing from one side of the framework layer (32) to the other side thereof.

Description

Stator of motor and method for manufacturing stator

[0001] Citation of Related Applications

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on October 24, 2023, with application number 202311376343.3 and invention name “Stator of Motor”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of motors, and more specifically to a stator of a motor and a method for manufacturing the stator. Background Art

[0004] With the continuous pursuit of motor power density in the industry, especially the new energy vehicle industry, the insulation performance and heat dissipation performance of the motor have become two important factors affecting the overall performance of the motor.

[0005] Regarding the heat dissipation problem of the motor stator, the more common heat dissipation method in the industry is to set up a heat dissipation channel on the outer surface of the stator and dissipate heat through oil cooling or water cooling; or to open an independent heat dissipation channel inside the iron core and dissipate heat through oil cooling.

[0006] However, how to make the heat dissipation channel simple in structure, not occupying extra space, and close to the winding area where heat is generated seriously is still a problem that can be further optimized in this field.

[0007] One approach to insulating the motor stator is to place insulating paper between the windings (also known as conductors) and the iron core, typically using insulating paper with a foaming material. The foaming material expands upon heating, filling the gaps within the stator slots.

[0008] However, the above-mentioned expansion material is prone to shedding, which can affect motor performance during operation. This is especially true when cooling oil flows through the stator, where the shedding of the expansion material can affect the normal flow of the cooling oil and even lead to serious consequences such as blocking the cooling oil circuit.

[0009] Summary of the Invention

[0010] The purpose of the present application is to overcome or at least alleviate the deficiencies of the above-mentioned prior art and to provide a stator for a motor and a method for manufacturing the stator.

[0011] According to a first aspect of the present application, a stator of a motor is provided, comprising: an iron core, a conductor, and an insulating sheet, wherein the iron core is formed with wire slots, the conductor and the insulating sheet are inserted into the wire slots, and the insulating sheet surrounds the conductor.

[0012] The iron core is further formed with a cooling liquid tank, which is in communication with the wire slot.

[0013] The insulating sheet includes a skeleton layer and an expansion layer. The skeleton layer is at least arranged on the surface of the expansion layer that is away from the conductor. The expansion layer does not contact the cooling liquid tank. The skeleton layer is made of an oil-resistant and high-temperature resistant material, and the skeleton layer can prevent liquid resin from flowing from one side of the skeleton layer to the other side.

[0014] In at least one embodiment, the insulating sheet includes two skeleton layers, and the expansion layer is sandwiched between the two skeleton layers.

[0015] In at least one embodiment, the skeleton layer is made of a material comprising: one of polyetherimide, polyphenylene sulfide, polyimide and polyetheretherketone;

[0016] The expansion layer is made of a material comprising one or more of a B-stage epoxy resin, a phenolic resin, a cyanate resin, a polyurethane resin, and a polyacrylate resin containing a foaming agent.

[0017] In at least one embodiment, an insulating resin is provided between the conductor and the insulating sheet, and no insulating resin is provided between the insulating sheet and the wall of the wire duct.

[0018] In at least one embodiment, the insulating resin is applied by a paint dripping process.

[0019] In at least one embodiment, the insulating sheet extends out from both axial ends of the stator to form extended ends, and the extended ends are formed in a funnel shape.

[0020] In at least one embodiment, the expansion temperature of the expansion layer of the insulation sheet is lower than the curing temperature of the insulation resin.

[0021] In at least one embodiment, the cooling liquid groove is provided between two adjacent slots in the circumferential direction of the stator.

[0022] In at least one embodiment, in the radial direction of the stator, the coolant groove is provided in a region close to the radial outer side of the wire slot.

[0023] In at least one embodiment, in the circumferential direction of the stator, at least two adjacent coolant grooves between adjacent slots are staggered in the radial direction.

[0024] According to a second aspect of the present application, a method for manufacturing a stator is provided. The method is used to manufacture the stator according to the first aspect of the present application, and the method comprises:

[0025] Folding and rolling the insulating sheet into a cylindrical shape and inserting the cylindrical shape into the cable duct;

[0026] inserting the conductor into the inner periphery of the cylindrical region of the insulating sheet;

[0027] Insulating resin is dripped or poured from the axial end portion of the core toward the inner periphery of the cylindrical region of the insulating sheet.

[0028] In at least one embodiment, before the insulating resin is dripped or poured into the inner periphery of the cylindrical region of the insulating sheet, the stator is heated to expand the expansion layer of the insulating sheet.

[0029] In at least one embodiment, before the insulating resin is dripped or poured into the inner periphery of the cylindrical region of the insulating sheet, the expansion layer of the insulating sheet does not expand or does not expand completely;

[0030] After dripping or pouring insulating resin into the inner periphery of the cylindrical region of the insulating sheet, the stator is heated.

[0031] When the heating temperature reaches a first heating temperature, the expansion layer expands and the insulating resin remains in a fluid state. When the heating temperature reaches a second heating temperature, the insulating resin solidifies. The first heating temperature is lower than the second heating temperature.

[0032] In at least one embodiment, when the heating temperature reaches the third heating temperature, the expansion layer is fully expanded.

[0033] The third heating temperature is greater than the first heating temperature and less than the second heating temperature.

[0034] The motor of this application has a simple stator structure and includes a coolant tank connected to the wire slots, enabling more direct and effective heat dissipation from the conductors. Furthermore, the wire slots are provided with insulating sheets that block the flow of resin. The insulating sheets not only enhance interphase insulation but also allow for the placement of insulating resin within the insulating sheets. This improves both the heat dissipation and insulation performance of the stator. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] 1 to 4 are cross-sectional views of partial structures of stators according to four possible embodiments of the present application.

[0036] 5 and 6 are schematic diagrams of layered structures of insulating sheets according to two possible embodiments of the present application.

[0037] FIG7 is a schematic diagram of some steps of a stator manufacturing process according to one embodiment of the present application.

[0038] Description of reference numerals:

[0039] 10 iron core; 11 wire slot; 12 coolant tank;

[0040] 20 conductors;

[0041] 30 insulating sheet; 31 expansion layer; 32 skeleton layer; 301 extended end;

[0042] 40 Insulation resin; 50 Tooling. DETAILED DESCRIPTION

[0043] The following describes exemplary embodiments of the present application with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all possible embodiments of the present application, nor to limit the scope of the present application.

[0044] 1 to 7 , a stator of a motor according to the present application is introduced.

[0045] Unless otherwise specified, in the figures, A represents the axial direction of the motor stator, R represents the radial direction of the motor stator, and C represents the circumferential direction of the motor stator.

[0046] 1 , the stator according to the present embodiment includes a core 10 , a conductor 20 , and an insulating sheet 30 .

[0047] The iron core 10 is formed with a plurality of wire slots 11 and a plurality of coolant tanks 12 (only one wire slot and one coolant tank are shown in FIG1 ). Conductors 20 are inserted into the wire slots 11. Preferably, the conductors 20 are flat copper wires with a generally rectangular cross-section, commonly referred to in the industry as flat wire windings or hairpin windings. Accordingly, the stator of the motor according to the present application is preferably the stator of a flat wire motor.

[0048] The cooling liquid tank 12 is used for passing a cooling liquid, such as engine oil. The wiring slot 11 and the cooling liquid tank 12 are connected so that the cooling liquid can flow into the wiring slot and flow very close to the conductor 20 to remove the heat generated by the conductor 20.

[0049] In the embodiment shown in FIG1 , the coolant groove 12 is located on the side of the wire slot 11 in the circumferential direction C and, in the radial direction R, in the radially outer region of the wire slot 11. This is because the circumferential width of the tooth portion between circumferentially adjacent wire slots 11 increases as it approaches the radially outer region. Providing the wire slot 11 can increase the tooth saturation level in this region, making the tooth saturation levels of the tooth portion between the wire slots 11 closer in the radial direction.

[0050] It should be understood that, depending on the actual size of the stator, the cooling liquid tank 12 may also be provided in a substantially central region in the radial direction R of the wire slot 11 , for example, referring to FIG. 2 , so as to cool the conductor 20 more evenly.

[0051] It should be understood that the present application does not limit the specific number, position and shape of the cooling liquid grooves 12 near each wire groove 11.

[0052] For example, referring to FIG. 3 , a coolant groove 12 may be provided on both sides of a wire groove 11 in the circumferential direction, and the two coolant grooves 12 may be staggered in the radial direction R so that the teeth between adjacent wire grooves 11 can be reasonably occupied.

[0053] For another example, referring to FIG4 , the cooling liquid tank 12 is located on the inner circumference of the wire slot 11. Alternatively, it can be considered that the cooling liquid tank 12 is located within the wire slot 11 and occupies the inner circumference of the wire slot 11. This arrangement can provide better cooling for the conductor 20 located radially inward, which is subject to severe heat generation, without changing the core structure as much as possible.

[0054] Next, an insulating sheet 30 according to the present application will be described with reference to Figures 1 and 5. The insulating sheet 30 includes an expansion layer 31 and a skeleton layer 32 that are stacked and connected together.

[0055] It should be understood that for various reasons such as convenience of display, the layered structure of the insulating sheet 30 is not shown in Figures 1 to 4 and 7, the overlapping seam edges of the folded insulating sheet 30 are not shown in Figures 2 to 4, and the proportional relationship of the various structures in the figures does not represent the actual situation.

[0056] The skeleton layer 32 is film-shaped and has a dense structure. The skeleton layer 32 is made of a material such as polyetherimide (abbreviated as PEI), polyphenylene sulfide (abbreviated as PPS), polyimide (abbreviated as PI) and polyetheretherketone (abbreviated as PEEK). The skeleton layer 32 is oil-resistant, high-temperature resistant, insoluble in resin and can block the flow of resin. Among them, oil resistance mainly refers to that it is not soluble in coolants such as engine oil and transmission oil; high-temperature resistance, for example, its temperature resistance is greater than 200 degrees Celsius; barrier resin, mainly for the insulating resin 40 that will be further introduced below, the skeleton layer 32 can prevent the liquid insulating resin 40 from flowing from one side of the skeleton layer 32 to the other side.

[0057] The expansion layer 31 is made of a material that can expand after heating, such as a composite of one or more of B-stage epoxy resin, phenolic resin, cyanate resin, polyurethane resin, and polyacrylate resin containing a foaming agent.

[0058] Regarding the insulating sheet 30 shown in Figure 5 , when inserted into the cable tray 11, the expansion layer 31 is positioned toward the conductor 20. Specifically, the skeleton layer 32 is located on the surface of the expansion layer 31 facing away from the conductor 20. This arrangement ensures that the portion of the insulating sheet 30 exposed to the coolant tank 12 is the skeleton layer 32, not the expansion layer 31. Therefore, the expansion layer 31 is prevented from falling off and entering the coolant tank 12. The hollow arrow in Figure 5 indicates the direction of the conductor.

[0059] In addition, the skeleton layer 32 made of, for example, PEI has a high structural strength, so that the portion of the insulating sheet 30 exposed to the cooling liquid tank 12 can stand upright opposite the cooling liquid tank 12, or become part of the outer wall of the cooling liquid tank 12.

[0060] 6 , in another possible embodiment, the insulating sheet 30 may include two skeleton layers 32 , and the two skeleton layers 32 sandwich the expansion layer 31 , thereby better preventing the expansion layer 31 from falling off.

[0061] Next, the form of the insulating sheet 30 formed in the wire slot 11 and the method of manufacturing the stator will be further described with reference to FIG. 7 .

[0062] Referring to steps (i) and (ii) in Figure 7 , the insulating sheet 30 is folded and rolled into a cylindrical shape before being inserted into the cable tray 11. The two protruding ends 301 of the insulating sheet 30 in the axial direction A, which are exposed from the core 10, are then expanded using a tool 50. The tool 50 may have a conical surface, for example, which can expand the protruding ends 301 into a funnel shape.

[0063] In step (iii), conductor 20 is inserted into the inner circumference of the cylindrical region of insulating sheet 30. Next, a dripping operation is performed, where insulating resin 40 is dripped or poured into the inner circumference of the cylindrical region of insulating sheet 30 from the axial end of core 10. The extended end 301 serves as a dripping port. Its funnel-shaped structure guides insulating resin 40 into the inner circumference of insulating sheet 30 while preventing it from entering and clogging the coolant tank 12 located on the outer circumference of insulating sheet 30.

[0064] The insulating resin 40 is, for example, one or more of unsaturated polyester resin, unsaturated polyesterimide resin, epoxy resin, polyimide resin, and the like.

[0065] After the paint is dripped, the stator is heated to solidify the insulating resin 40, thereby obtaining a stator with a stable structure and good insulation effect.

[0066] The addition of the insulating resin 40 has the following benefits: first, it can fill the gaps between the conductors 20 that the insulating sheet 30 cannot fill, thereby enhancing the insulation performance; second, the cured insulating resin 40 can serve as the inner lining of the cylindrical insulating sheet 30, thereby increasing the structural strength of the insulating sheet 30, and since the insulating sheet 30 also serves as part of the wall of the cooling liquid tank 12, the structure of the cooling liquid tank 12 is also stable; third, the insulating resin 40 can further form a sealing protection for the expansion layer of the insulating sheet 30 toward the inner circumference, thereby preventing the expansion layer from falling off.

[0067] The above-mentioned operations of heating and curing the insulating resin 40 and heating and expanding the insulating sheet 30 can be combined; or the expansion layer of the insulating sheet 30 can be heated first to expand, and then the paint dripping and curing operations are performed. For example, before dripping the paint, the stator is first heated to expand the expansion layer 31 of the insulating sheet 30.

[0068] In the case of a combined operation, the expansion temperature of the expansion layer is preferably lower than the curing temperature of the insulating resin 40, so that during the heating process, the expansion layer can expand first; and during this process, the insulating resin 40 remains in a flowable state, thereby further filling the gaps between the conductors 20. For example, before the paint is applied, the expansion layer 31 has not expanded or has not fully expanded. After the paint is applied, the stator is heated. When the heating temperature reaches the first heating temperature, the expansion layer 31 begins to dynamically expand, while the insulating resin 40 remains in a flowable state. When the heating temperature gradually rises to the second heating temperature, the insulating resin 40 solidifies. When the heating temperature continues to rise to the third heating temperature, the expansion layer 31 is fully expanded.

[0069] It should be understood that the above-mentioned embodiments and some aspects or features thereof may be appropriately combined.

[0070] This application has at least one of the following advantages:

[0071] (i) The stator according to the present application has a cooling liquid groove that can be connected to the wire slot, so that the cooling oil can flow around the conductor at a closer distance, taking away the heat generated by the conductor, and achieving a good heat dissipation effect.

[0072] (ii) The insulating sheet forms a part of the wall of the cooling liquid tank, which makes the cooling liquid tank simple in structure and low in manufacturing cost.

[0073] (iii) The skeleton layer of the insulating sheet has the function of hindering the flow of insulating resin. When the core is dripped with paint to enhance the insulation performance, the insulating resin will not flow into the coolant tank and form a blockage.

[0074] (iv) In the case where the insulating sheet has an expansion layer, dripping paint on the inner periphery of the insulating sheet can not only enhance the insulation performance but also prevent the expansion layer from falling off.

[0075] Of course, the present application is not limited to the above embodiments, and those skilled in the art can make various modifications to the above embodiments under the guidance of the present application without departing from the scope of the present application. For example:

[0076] (i) The insulating sheet may not have an expansion layer but may have only a skeleton layer.

[0077] (ii) Although the skeleton layer of the insulating sheet according to the present application has the property of blocking the flow of resin, the stator according to the present application may not perform the dripping operation, that is, the insulating resin is not provided on the inner circumference side of the insulating sheet.

Claims

1. A stator of a motor, comprising: An iron core (10), a conductor (20) and an insulating sheet (30), wherein the iron core (10) is formed with a wire groove (11), the conductor (20) and the insulating sheet (30) are inserted into the wire groove (11), and the insulating sheet (30) surrounds the conductor (20), wherein: The iron core (10) is further formed with a cooling liquid groove (12), and the cooling liquid groove (12) is connected to the wire groove (11). The insulating sheet (30) comprises a skeleton layer (32) and an expansion layer (31), wherein the skeleton layer (32) is at least arranged on a surface of the expansion layer (31) that is used to face away from the conductor (20), and the expansion layer (31) does not contact the cooling liquid tank (12). The skeleton layer (32) is made of an oil-resistant and high-temperature-resistant material, and the skeleton layer (32) can prevent liquid resin from flowing from one side of the skeleton layer (32) to the other side.

2. The stator of the motor according to claim 1, wherein: The insulating sheet (30) comprises two skeleton layers (32), and the expansion layer (31) is sandwiched between the two skeleton layers (32).

3. The stator of the motor according to claim 1, wherein: The skeleton layer (32) is made of a material selected from the group consisting of polyetherimide, polyphenylene sulfide, polyimide and polyetheretherketone; The expansion layer (31) is made of a material comprising: a B-stage epoxy resin containing a foaming agent, a phenolic resin, a cyanate resin, a polyurethane resin, a polyacrylate resin, or a composite of several of the above.

4. The stator of the motor according to claim 1, wherein: An insulating resin (40) is provided between the conductor (20) and the insulating sheet (30), and the insulating resin (40) is not provided between the insulating sheet (30) and the wall of the wire duct (11).

5. The stator of the motor according to claim 4, wherein: The insulating resin (40) is applied by a paint dripping process.

6. The stator of the motor according to claim 4, wherein: The insulating sheet (30) extends out from both axial ends of the stator to form extended ends (301), and the extended ends (301) are formed in a funnel shape.

7. The stator of the motor according to claim 4, wherein: The expansion temperature of the expansion layer (31) of the insulation sheet (30) is lower than the curing temperature of the insulation resin (40).

8. The stator of the motor according to claim 1, wherein: In the circumferential direction of the stator, the cooling liquid groove (12) is arranged between two adjacent wire grooves (11).

9. The stator of the motor according to claim 8, wherein: In the radial direction of the stator, the cooling liquid groove (12) is arranged in a region close to the radial outer side of the wire groove (11).

10. The stator of the motor according to claim 8, wherein: In the circumferential direction of the stator, at least two adjacent cooling liquid grooves (12) between adjacent wire grooves (11) are staggered in the radial direction.

11. A method for manufacturing a stator, wherein: The method is used to manufacture the stator of the motor according to any one of claims 1 to 10, and the method comprises: The insulating sheet (30) is folded and rolled into a cylindrical shape and inserted into the wire slot (11); Inserting the conductor (20) into the inner periphery of the cylindrical region of the insulating sheet (30); An insulating resin (40) is dripped or poured from the axial end of the iron core (10) toward the inner periphery of the cylindrical region of the insulating sheet (30).

12. The method for manufacturing a stator according to claim 11, wherein: Before the insulating resin (40) is dripped or poured into the inner periphery of the cylindrical region of the insulating sheet (30), the stator is heated to expand the expansion layer (31) of the insulating sheet (30).

13. The method for manufacturing a stator according to claim 11, wherein: Before the insulating resin (40) is dripped or poured into the inner periphery of the cylindrical region of the insulating sheet, the expansion layer (31) of the insulating sheet (30) has not expanded or has not fully expanded; After dripping or pouring insulating resin (40) into the inner periphery of the cylindrical region of the insulating sheet, the stator is heated. When the heating temperature reaches a first heating temperature, the expansion layer (31) expands and the insulating resin (40) remains in a fluid state. When the heating temperature reaches a second heating temperature, the insulating resin (40) solidifies. The first heating temperature is lower than the second heating temperature.

14. The method for manufacturing a stator according to claim 13, wherein: When the heating temperature reaches the third heating temperature, the expansion layer (31) is fully expanded. The third heating temperature is greater than the first heating temperature and less than the second heating temperature.

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