High-power-density motor coil and manufacturing method and assembling method thereof

Abstract

The invention belongs to the technical field of motors, and particularly relates to a high-power-density motor coil and a manufacturing method and an assembling method thereof. On the premise of meeting the performance requirement of a high-power torque density motor, the stator has excellent manufacturability, the external heat dissipation effect of the winding can be greatly improved, the effective use area in the slot is increased, and the performance of the motor is improved. Comprising a non-wire outlet end, an iron core groove inner coil part and a wire outlet end, the coil is composed of a flat wire, the cross section of a flat wire enameled wire is a rectangle with the length-width ratio not equal to 1, and the flat wire enameled wire is bent in the wide ridge direction instead of the narrow ridge direction.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and in particular relates to a high power density motor coil and a manufacturing method and an assembly method thereof. Background Art

[0002] In the field of motor technology, motor coil designs at home and abroad present a variety of structural forms. Among them, flat wire is the basic winding form of coil and is widely used in automotive motors, high-voltage motors and other fields.

[0003] In terms of automotive motors, winding span>1 (common poles are 6, 8, 10, and 12) is often used. However, this type of automotive motor has obvious defects, including extremely high production equipment costs, difficult manufacturing processes, and difficulty in extending series products on the same core specification, which greatly increases production difficulty.

[0004] High-voltage motors use insulating materials to bend and shape flat wires, wind the coils with multiple layers of insulation, and finally embed them into the stator core of the motor. However, the existence of multiple layers of slot insulation seriously weakens the heat dissipation effect of the windings, affecting the performance of the motor.

[0005] It can be seen that although the existing motor product design can meet some of the needs of the corresponding industry, there are still many unavoidable problems. Especially in the face of the strict requirements of high power density and high torque density in pure electric aircraft working conditions, the limitations of the above traditional solutions are becoming more and more prominent, and it is difficult to meet new development requirements. Summary of the invention

[0006] The present invention aims at solving the defects in the prior art and provides a high power density motor coil and a manufacturing method and an assembly method thereof.

[0007] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a high power density motor coil, including a non-outlet terminal, a coil part in a core slot, and an outlet terminal, wherein the coil is composed of a flat wire, wherein the cross-section of the flat enameled wire is a rectangle with an aspect ratio not equal to 1, and the bending direction is along the wide flute direction rather than the narrow flute direction.

[0008] Furthermore, the bending parts (ie, the bending positions) of each turn of the coil are staggered along the width direction to ensure that the bending points do not overlap at the same position, thereby preventing insulation damage and maintaining the consistency of the size of the flat wire.

[0009] Furthermore, the offset range of the bending parts of two adjacent turns of the coil is 2 to 8 mm.

[0010] Furthermore, the portion of the coil that cooperates with the core stator teeth has a trapezoidal cross-section, that is, the two straight lines of the coil along the cross-sectional direction are not parallel, and the tooth shape that cooperates with the core stator teeth is a trapezoidal tooth (on the stator core of the motor, the teeth used for winding installation (i.e., stator teeth) have a trapezoidal cross-sectional shape); this allows the coil to fit more closely to the core during assembly, thereby increasing the efficiency of external heat dissipation.

[0011] Furthermore, the coil output terminal and the non-output terminal are both in a staggered stepped shape, and there is no limit on the number of staggered or stepped layers, so as to optimize the overall performance of the motor winding.

[0012] Furthermore, the coil is constructed by vertically winding a flat wire.

[0013] Furthermore, each turn of the coil is in direct contact with the iron core through the insulating material, so that the external heat dissipation conditions of each turn of the coil are the same, thereby avoiding the aggravation of local insulation thermal aging caused by uneven winding temperature.

[0014] A method for manufacturing a high power density motor coil comprises the following steps:

[0015] S1. Select a rectangular enameled wire with a cross-section and an aspect ratio not equal to 1 as the winding material;

[0016] S2, bend the flat wire along the wide corrugation direction to form a multi-turn coil (at least 3 turns);

[0017] S3. During the bending process, ensure that the bending point (i.e., the bending position) of each coil turn is staggered by 2 to 8 mm in the wide corrugation direction to avoid damage to the insulating paint film layer and thinning and thickening of the flat wire bending position due to stretching and compression;

[0018] S4, assembling the bent flat wire into a coil with a trapezoidal cross-section, so that the coil can fit closely with the stator teeth of the iron core to improve the external heat dissipation efficiency;

[0019] S5. Install the formed trapezoidal cross-section coil into the stator core slot of the motor, ensure that each coil turn is in direct contact with the core through the insulating material, ensure that the external heat dissipation conditions of each coil turn are the same, and prevent the local insulation thermal aging from being aggravated;

[0020] S6. Perform quality inspection on the stator coil after assembly to ensure that there is no insulation damage, dimensional changes and that the electrical performance meets the design requirements.

[0021] Furthermore, the flat wire material is made of a copper alloy with high conductivity and is preheated before bending to reduce stress concentration during the bending process.

[0022] A method for assembling a high power density motor coil comprises the following steps:

[0023] S001. Provide a coil structure;

[0024] 1) Before assembly, clean and dry the coil to remove oil and impurities on the surface;

[0025] 2) Clean and insulate the inner wall of the core slot;

[0026] S002. Assemble the coil into the core slot along the trapezoidal teeth, ensuring that the two straight lines inside the coil are not parallel;

[0027] S003. Make the coil directly contact with the iron core through insulating materials to ensure the same heat dissipation conditions for each turn of the coil;

[0028] S004. During the assembly process, avoid relative sliding between the insulating material and the iron core to reduce damage to the insulating material.

[0029] Compared with the prior art, the present invention has beneficial effects.

[0030] The present invention has excellent processability while meeting the performance requirements of high power torque density motors. While ensuring insulation strength, improving motor reliability and extending service life, it can greatly improve the external heat dissipation effect of the winding, increase the effective use area in the slot, and improve motor performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. The protection scope of the present invention is not limited to the following description.

[0032] Figure 1 It is a schematic diagram of the structure of a high power density motor coil according to an embodiment.

[0033] Figure 2 It is a partial enlarged structural schematic diagram of the high power density motor coil of the embodiment.

[0034] Figure 3 It is a front view of the high power density motor coil of the embodiment.

[0035] Figure 4 is a top view of a high power density motor coil according to an embodiment.

[0036] Figure 5 yes Figure 4 AA section view.

[0037] Figure 6-7 This is an example of a trapezoidal tooth fit. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and beneficial effects of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0039] like Figure 1-7 As shown, a specific embodiment: a high power density motor coil structure includes a non-outlet terminal 1, a coil part 2 in the core slot, and an outlet terminal 3. The coil is composed of a flat wire, wherein the cross-section of the flat wire enameled wire is a rectangle with an aspect ratio not equal to 1, and the aspect ratio of the flat wire is 1.8 to 3.5. And the bending direction is along the wide flute direction rather than the narrow flute direction. Among them, the bending direction of the flat wire is along the wide flute direction rather than the traditional narrow flute direction, so that the characteristics of the flat wire can be better utilized and the damage to the insulation layer of the enameled wire during the bending process can be reduced.

[0040] Embodiment 1: The bending parts (i.e., the bending positions) of each coil turn are staggered along the width direction to ensure that the bending points do not overlap at the same position, thereby preventing insulation damage and maintaining the consistency of the flat wire size. Moreover, the staggered range of the bending parts of two adjacent coil turns is 2 to 8 mm. The specific value depends on the length-to-width ratio of the flat wire, the vertical winding bending deformation, and the insulation damage.

[0041] That is, each turn of the coil (or each layer of the coil) does not overlap at the bending position, and the specific staggered distance is 2 to 8 mm, so as to avoid inter-turn disconnection caused by damage to the insulating paint film layer and solve the problem of thinning and thickening of the flat wire due to stretching and compression.

[0042] Specifically, the bending positions of each coil turn (each layer of coil) do not overlap, such as: bending outer circles 4, 5, 6, and bending inner circles 7, 8. During the bending process of the flat wire, the outer circle of the bend is stretched and the inner circle is compressed, which will cause the enameled wire film to be stretched and compressed to varying degrees, which can easily cause the insulation layer to be damaged. In addition, the copper material itself will be stretched and compressed, which will cause the stretched part to become thinner and the compressed part to become thicker. The non-overlapping bending positions can effectively avoid the problem of thinning and thickening of the flat wire bending position due to stretching and compression, which will cause the stacking height of the multi-layer (multi-turn) coil to change along the narrow flute direction.

[0043] Embodiment 2: The part where the coil matches with the core stator teeth is a trapezoidal cross section, that is, the two straight lines (i.e., straight line 1 9 and straight line 2 10) of the coil along the cross-sectional direction are not parallel, and the tooth shape that matches with the core stator teeth is a trapezoidal tooth, that is, on the stator core of the motor, the teeth used for winding installation (i.e., stator teeth) have a trapezoidal cross-sectional shape; so that the coil can fit the core more closely during assembly, thereby increasing the efficiency of external heat dissipation. In addition, during the assembly process of the coil, the insulating material and the core do not have to slide relative to each other like parallel teeth, thereby avoiding damage to the insulating material and increasing the safety and reliability of the product. At the same time, the contact between the coil and the core stator teeth depends on the pressure applied to the coil in the direction of the trapezoidal height. The greater the pressure, the greater the force component of the winding acting vertically on the core teeth, and the closer the contact with the core teeth; the improvement of the contact effect reduces the thermal resistance and improves the efficiency of external heat dissipation.

[0044] Embodiment 3: The coil outlet terminal 3 and the non-outlet terminal 1 are both staggered and stepped, and the number of staggered or stepped layers is not limited, so as to optimize the overall performance of the motor winding. It solves the problem of flat wire coil production processability, and also solves the problem of insulation damage risk at the flat wire bending position, and avoids the problem of flat wire size change caused by stretching thinning and compression thickening.

[0045] Furthermore, the coil is constructed by vertically winding a flat wire.

[0046] In the preferred solution, each turn of the coil is in direct contact with the iron core through the insulating material, so that the external heat dissipation conditions of each turn of the coil are the same, thereby avoiding the aggravation of local insulation thermal aging caused by uneven winding temperature.

[0047] Embodiment 4: A method for manufacturing a high power density motor coil, comprising the steps of:

[0048] S1. Select a rectangular enameled wire with a cross-section and an aspect ratio not equal to 1 as the winding material.

[0049] S101. The flat wire material is made of a high-conductivity copper alloy and is preheated before bending to reduce stress concentration during the bending process. The preheating temperature is controlled at 150°C to 200°C.

[0050] S2. Bend the flat wire along the wide direction to form a multi-turn coil.

[0051] Use lubricants to reduce friction during the bending process to prevent insulation wear.

[0052] S3. During the bending process, ensure that the bending point (i.e. bending position) of each turn of the coil is staggered by 2 to 8 mm in the direction of the wide corrugation to avoid damage to the insulating paint film layer and thinning and thickening of the flat wire bending position due to stretching and compression.

[0053] Among them, according to stress distribution theory, the stress is the largest at the bending point. If multiple turns of coils are bent at the same position, the stress will be superimposed, increasing the probability of damage. By staggering the bending points by 2 to 8 mm along the width direction, the stress is effectively dispersed and the failure rate is reduced. Moreover, the staggered arrangement of the bending points of each turn of the coil is also conducive to improving the overall heat dissipation effect of the winding, because the heat distribution at different positions is more uniform, avoiding the formation of hot spots. According to the theory of heat conduction, uniform heat distribution is conducive to improving the overall heat dissipation efficiency of the system.

[0054] S4. Assemble the bent flat wire into a coil with a trapezoidal cross-section, so that the coil can fit closely with the stator teeth of the iron core to improve the external heat dissipation efficiency.

[0055] The trapezoidal cross-section design allows the coil to fit more closely to the core surface, reducing the air gap and improving the heat conduction efficiency. According to Fourier's law of heat conduction, thermal resistance is proportional to the thickness of the medium, so reducing the thickness of the air layer between the contact interfaces can directly improve the heat transfer efficiency, thereby enhancing the cooling capacity of the motor.

[0056] S5. Install the formed trapezoidal cross-section coil into the motor stator core slot to ensure that each coil turn is in direct contact with the core through the insulating material, ensure that the external heat dissipation conditions of each coil turn are the same, and prevent the local insulation thermal aging from being aggravated.

[0057] In addition, before step S5, the inner wall of the core slot can be insulated (coated with insulating paint or pasted with insulating film) to prevent the risk of short circuit caused by direct contact between the coil and the core. At the same time, during the assembly process, thermal conductive glue or thermal conductive gasket can be used to fill the gap between the coil and the core to improve the heat dissipation efficiency.

[0058] S6. Perform quality inspection on the stator coil after assembly to ensure that there is no insulation damage, dimensional changes and that the electrical performance meets the design requirements.

[0059] Embodiment 5, a method for assembling a high power density motor coil, taking 24 teeth as an example, comprises the following steps:

[0060] S001, providing a coil structure; specifically comprising the following steps:

[0061] 1) Before assembly, clean and dry the coil to remove oil and impurities on the surface to ensure the adhesion of the insulating material.

[0062] 2) Clean and insulate the inner wall of the core slot to ensure that there are no impurities and damage during the assembly process.

[0063] 3) Prepare glue, assembly fixtures, and PTFE strips.

[0064] S002. Assemble the coil into the core slot along the trapezoidal teeth, ensuring that the two straight lines inside the coil are not parallel;

[0065] Taking 24 teeth as an example, the specific steps include: inserting the coils in a counterclockwise direction, in three groups, with 8 in each group.

[0066] S003. Make the coil directly contact with the iron core through insulating material to ensure the same external heat dissipation conditions for each turn of the coil.

[0067] 1) Use adhesive and PTFE tape to fix the coil to ensure that the external heat dissipation conditions of each turn of the coil are the same.

[0068] 2) Check whether the insulating material evenly covers the coil surface.

[0069] S004. During the assembly process, avoid relative sliding between the insulating material and the iron core to reduce damage to the insulating material.

[0070] Among them, it is necessary to pay attention to inserting the coil slowly and avoid over-tightening the clamp. And check whether the clamp is aligned to avoid damage to the insulation material.

[0071] S005. Let it stand for at least 24 hours to allow the glue to fully solidify. Remove the clamp and PTFE strips and clean up the excess solidified glue.

[0072] It should be noted that the high power density coil is:

[0073] Volume power density: above 20kW / L.

[0074] Weight power density: above 5kW / kg.

[0075] The exact values ​​depend on the area of ​​application and the technology.

[0076] The technical objectives and effects achieved by the technical solution of the present invention are:

[0077] 1. The flat wire vertical winding structure increases the effective area in the slot, the trapezoidal cross-section of the coil further optimizes the space utilization, and the staggered design avoids the problem of coil size changes. The three work together to enable the motor to output higher power and torque at the same size.

[0078] 2. The trapezoidal cross-section design of the coil makes the coil fit closely with the iron core. The flat wire vertical winding structure and the staggered structure make the heat dissipation conditions of each turn of the coil uniform. The three work together to significantly improve the heat dissipation efficiency of the winding and avoid local overheating problems.

[0079] 3. The coil outlet terminal 3 and the non-outlet terminal 1 are both staggered and stepped, which avoids the problems of insulation paint film damage and flat wire size change. The flat wire vertical winding structure simplifies the production process, and the trapezoidal cross-section design improves assembly reliability. The three work together to make the motor more manufacturable and more reliable.

[0080] That is to say, by optimizing the heat dissipation conditions and insulation strength, local overheating and insulation aging problems are avoided, and the service life of the motor is extended. It is not only applicable to pure electric fixed-wing aircraft motors, but can also be extended to other high-power density application scenarios such as automotive motors and industrial motors.

[0081] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "preferred embodiments", "specific implementation", or "preferred implementation" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, it should be understood by those skilled in the art that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features therein may be replaced by equivalents. Therefore, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. A high power density motor coil, characterized in that: It comprises a non-outlet terminal (1), a coil part (2) in an iron core slot, and an outlet terminal (3), wherein the coil is composed of a flat wire, wherein the cross section of the flat enameled wire is a rectangle with an aspect ratio not equal to 1, and the bending direction is along the wide flute direction rather than the narrow flute direction.

2. The high power density motor coil according to claim 1, characterized in that: The bending parts of each turn of the coil are staggered along the width direction to ensure that the bending points do not overlap at the same position, thereby preventing insulation damage and maintaining the consistency of the flat wire size.

3. The high power density motor coil according to claim 2, characterized in that: The staggered range of the bending parts of two adjacent turns of the coil is 2 to 8 mm.

4. The high power density motor coil according to claim 1, characterized in that: The part where the coil matches with the core stator teeth is a trapezoidal cross section, that is, two straight lines of the coil along the cross section are not parallel, and the teeth matching with the core stator teeth are trapezoidal teeth; this allows the coil to fit more closely to the core during assembly, thereby increasing the efficiency of external heat dissipation.

5. The high power density motor coil according to claim 1, characterized in that: The coil output terminal (3) and the non-output terminal (1) are both in a staggered stepped shape, and the number of staggered or stepped layers is not limited, so as to optimize the overall performance of the motor winding.

6. The high power density motor coil according to claim 1, characterized in that: The coil is constructed by vertical winding of flat wire.

7. The high power density motor coil according to claim 1, characterized in that: Each turn of the coil is in direct contact with the iron core through the insulating material, so that the external heat dissipation conditions of each turn of the coil are the same, avoiding the aggravation of local insulation thermal aging caused by uneven winding temperature.

8. A method for manufacturing a high power density motor coil, characterized in that: Includes steps: S1. Select a rectangular enameled wire with a cross-section and an aspect ratio not equal to 1 as the winding material; S2, bending the flat wire along the wide corrugation direction to form a multi-turn coil; S3. During the bending process, ensure that the bending points of each coil turn are staggered by 2 to 8 mm in the direction of the wide corrugation to avoid damage to the insulating paint film layer and thinning and thickening of the flat wire bending position due to stretching and compression; S4, assembling the bent flat wire into a coil with a trapezoidal cross-section, so that the coil can fit closely with the stator teeth of the iron core to improve the external heat dissipation efficiency; S5. Install the formed trapezoidal cross-section coil into the stator core slot of the motor, ensure that each coil turn is in direct contact with the core through the insulating material, ensure that the external heat dissipation conditions of each coil turn are the same, and prevent the local insulation thermal aging from being aggravated; S6. Perform quality inspection on the assembled stator coil.

9. The method for manufacturing a high power density motor coil according to claim 8, characterized in that: The flat wire material is made of a copper alloy with high conductivity and is preheated before bending to reduce stress concentration during the bending process.

10. A method for assembling a high power density motor coil, characterized in that: Includes steps: S001. Providing a coil according to any one of claims 1 to 7; further comprising: 1) Before assembly, clean and dry the coil to remove oil and impurities on the surface; 2) Clean and insulate the inner wall of the core slot; S002. Assemble the coil into the core slot along the trapezoidal teeth, ensuring that the two straight lines inside the coil are not parallel; S003. Make the coil directly contact with the iron core through insulating materials to ensure the same heat dissipation conditions for each turn of the coil; S004. During the assembly process, avoid relative sliding between the insulating material and the iron core to reduce damage to the insulating material.

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