Special-shaped insulated wire

Abstract

The utility model discloses a special-shaped insulated wire which comprises a conductor and an insulating paint layer covering the outer surface of the conductor, and the cross section of the conductor comprises a first straight edge and a second straight edge which are parallel to each other, and a semi-elliptical edge which is connected with the same-side end parts of the first straight edge and the second straight edge. The two ends of the first straight edge and the two ends of the second straight edge are both connected with semi-oval edges, the two semi-oval edges are oppositely arranged, the long axis of each semi-oval edge is perpendicular to the first straight edge and the second straight edge, and the length of each semi-oval edge is equal to the perpendicular distance between the first straight edge and the second straight edge. The short axis of the semi-oval side is parallel to the first straight side and the second straight side, and the length of the semi-oval side is smaller than 1 / 2 of the vertical distance between the first straight side and the second straight side. According to the special-shaped insulated wire provided by the utility model, the cross section shape of the conductor is improved, so that the special-shaped insulated wire has better leveling property and heat dissipation property, the painting uniformity is improved, the uniformity of the insulating paint layer is improved, the insulating paint layer is not easy to crack during winding, the slot fullness rate is improved, and the mechanical property and the electrical property are improved and are more stable.

Description

Technical Field

[0001] The utility model relates to the technical field of electric conductors, and more specifically, to a special-shaped insulated electric wire. Background Art

[0002] Insulated wire is a wire with an insulating paint layer on the conductor. It is mainly used to realize the conversion of electromagnetic energy in electrical equipment and is one of the main components of transformers. Insulated wire consists of two parts: conductor and insulating paint layer. According to different shapes, conductors and insulating materials, insulated wires have different classifications.

[0003] According to the shape, insulated wires are divided into two shapes: flat wire and round wire. Flat wire is conducive to improving the slot fill rate of the motor. Generally, the slot fill rate of round wire motor is about 40%, while the slot fill rate of flat wire motor can reach more than 60%. The improvement of slot fill rate means that more conductors can be filled in under the premise of unchanged space, generating stronger magnetic field strength and improving its power density.

[0004] At present, the four corners of the conductor cross section in the industry are set as rounded chamfers, such as Figure 1 The R part is shown, and the fillet radius r is designed to be 1 / 4-1 / 2 of the conductor thickness. When painting, the insulating paint layer is prone to uneven painting at the fillet. When the inner diameter of the vertical winding is less than 2 times the wire width, the insulating paint layer is prone to cracking, the mechanical properties are unstable, and thus the electrical properties are unstable. Utility Model Content

[0005] In view of the shortcomings of the prior art, the utility model innovatively provides a special-shaped insulated wire, which has better leveling and heat dissipation properties by improving the cross-sectional shape of the conductor, improves the uniformity of painting, improves the uniformity of the insulating paint layer, and makes the insulating paint layer less likely to crack during winding. At the same time, the slot fill rate is improved, and both the mechanical and electrical properties are improved and more stable.

[0006] To achieve the above technical objectives, the utility model discloses a special-shaped insulated wire, comprising a conductor and an insulating paint layer covering the outer surface of the conductor, wherein the cross section of the conductor comprises a first straight side and a second straight side parallel to each other, and a semi-elliptical side connecting the ends on the same side of the first straight side and the second straight side, both ends of the first straight side and the second straight side are connected to the semi-elliptical side, the two semi-elliptical sides are arranged opposite to each other, the major axis of the semi-elliptical side is perpendicular to the first straight side and the second straight side and the length is the same as the vertical distance between the first straight side and the second straight side, and the minor axis of the semi-elliptical side is parallel to the first straight side and the second straight side and the length is less than 1 / 2 of the vertical distance between the first straight side and the second straight side.

[0007] Furthermore, the length of the short axis of the semi-elliptical side is 1 / 5 to 1 / 3 of the vertical distance between the first straight side and the second straight side.

[0008] Furthermore, the length of the short axis of the semi-elliptical side is 1 / 4 of the vertical distance between the first straight side and the second straight side.

[0009] Furthermore, the sum of the lengths of the first straight side or the second straight side and the short axes of the two semi-elliptical sides is 1-2 times the vertical distance between the first straight side and the second straight side.

[0010] Furthermore, the sum of the lengths of the first straight side or the second straight side and the short axes of the two semi-elliptical sides is 1.1-2 times the vertical distance between the first straight side and the second straight side.

[0011] Furthermore, a vertical distance between the first straight edge and the second straight edge is 0.500 mm-2.000 mm.

[0012] Furthermore, the conductor is copper, aluminum, copper alloy or aluminum alloy.

[0013] Furthermore, the insulating paint layer is a polyurethane layer, a polyetherimide layer, a polyimide layer or a polyamide-imide layer.

[0014] Furthermore, the insulating paint layer is formed by coating felt with paint liquid, and the viscosity of the paint liquid is 90-150cp.

[0015] Furthermore, the insulating paint layer is formed by coating a paint liquid through a mold, and the viscosity of the paint liquid is 2000-3000cp.

[0016] The beneficial effects of the utility model are:

[0017] The special-shaped insulated wire of the utility model has better leveling and heat dissipation properties by improving the cross-sectional shape of the conductor, improves the uniformity of paint coating, makes the insulating paint layer more uniform, and is not easy to crack during winding. At the same time, the slot fill rate is improved, and the mechanical and electrical properties are improved and more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the conductor cross section of an existing special-shaped insulated wire;

[0019] Figure 2 It is a schematic structural diagram of the conductor cross section of the special-shaped insulated wire in an embodiment of the utility model;

[0020] Figure 3a is a conductor cross-section comparison diagram of the special-shaped insulated wire with a conventional round chamfer radius of 1 / 2t and 1 / 4t and the special-shaped insulated wire of this embodiment when the width-to-thickness ratio is 1;

[0021] Figure 3b 1 is a diagram comparing conductor cross-sections of the conventional special-shaped insulated wires with chamfer radii of 1 / 2t and 1 / 4t and the special-shaped insulated wire of the present embodiment when the width-to-thickness ratio is 2;

[0022] Figure 4a 1 is a diagram comparing conductor cross-sections of the special-shaped insulated wires of the prior art with chamfer radii of 1 / 2t and 1 / 3t and the special-shaped insulated wires of the present embodiment when the width-to-thickness ratio is 1;

[0023] Figure 4b It is a conductor cross-section comparison diagram of the special-shaped insulated wire with the existing round chamfer radius of 1 / 2t and 1 / 3t and the special-shaped insulated wire of this embodiment when the width-to-thickness ratio is 2.

[0024] In the figure,

[0025] 1. The first straight side; 2. The second straight side; 3. The semi-elliptical side. DETAILED DESCRIPTION

[0026] The special-shaped insulated wire provided by the utility model is explained and illustrated in detail below in conjunction with the drawings of the specification.

[0027] This embodiment specifically discloses a special-shaped insulated wire, including a conductor and an insulating paint layer covering the outer surface of the conductor, such as Figure 2 As shown, the cross section of the conductor includes a first straight side 1 and a second straight side 2 which are parallel to each other, and a semi-elliptical side 3 connecting the ends of the first straight side 1 and the second straight side 2 on the same side. The two ends of the first straight side 1 and the second straight side 2 are both connected with the semi-elliptical side 3. The two semi-elliptical sides 3 are arranged opposite to each other, and the centers of the two semi-elliptical sides 3 are close to each other, that is, the arcs of the semi-elliptical sides 3 protrude away from each other; the lengths of the first straight side 1 and the second straight side 2 are the same, the ends of the first straight side 1 and the second straight side 2 are aligned one by one, the major axis of the semi-elliptical side 3 is perpendicular to the first straight side 1 and the second straight side 2, and the length is the same as the vertical distance between the first straight side 1 and the second straight side 2, and the distance between the first straight side 1 and the second straight side 2 is equal to the vertical distance between the first straight side 1 and the second straight side 2. The vertical distance between the first straight side 1 and the second straight side 2 is the thickness t of the conductor, and the length of the major axis of the semi-elliptical side 3 is d=t; the minor axis of the semi-elliptical side 3 is parallel to the first straight side 1 and the second straight side 2 and its length is less than 1 / 2 of the vertical distance between the first straight side 1 and the second straight side 2, that is, the length of the minor axis of the semi-elliptical side 3 a<1 / 2t; preferably, the length of the minor axis of the semi-elliptical side 3 is 1 / 5 to 1 / 3 of the vertical distance between the first straight side 1 and the second straight side 2, that is, the range of the length a of the minor axis of the semi-elliptical side 3 is: 1 / 5t≤a≤1 / 3t; more preferably, the length of the minor axis of the semi-elliptical side 3 is 1 / 4 of the vertical distance between the first straight side 1 and the second straight side 2, that is, the length of the minor axis of the semi-elliptical side 3 a=1 / 4t.

[0028] The sum of the lengths of the short axes of the first straight side 1 or the second straight side 2 and the two semi-elliptical sides 3 is 1-2 times the vertical distance between the first straight side 1 and the second straight side 2, and the sum of the lengths of the short axes of the first straight side 1 and the two semi-elliptical sides 3 or the sum of the lengths of the short axes of the second straight side 2 and the two semi-elliptical sides 3 is the width L of the conductor, and L is 1-2 times of t. In order to improve the slot fill rate, preferably, the conductor is set as a flat wire, and the sum of the lengths of the short axes of the first straight side 1 or the second straight side 2 and the two semi-elliptical sides 3 is 1.1-2 times the vertical distance between the first straight side 1 and the second straight side 2, that is, the width-to-thickness ratio is 1.1-2.

[0029] Furthermore, the vertical distance between the first straight side 1 and the second straight side 2 is 0.500mm-2.000mm, that is, the thickness t of the conductor is 0.500mm-2.000mm. The width-to-thickness ratio and thickness setting of the conductor can effectively control the processing amount of the conductor cross-section forming mold, avoid the conductor from breaking during the straightening process, so that the conductor can be processed smoothly while ensuring the performance of the conductor, and also improve the slot fill rate of the special-shaped insulated wire and improve the electrical performance.

[0030] In this embodiment, the conductor is copper, aluminum, copper alloy or aluminum alloy.

[0031] The insulating varnish layer is a polyurethane (PU) layer, a polyetherimide (PEI) layer, a polyimide (PI) layer or a polyamide-imide (PAI) layer, and has good self-adhesion, which helps to improve the tightness between the stacked special-shaped insulated wires, thereby improving the performance of the coil formed by stacking and winding the special-shaped insulated wires.

[0032] In some embodiments, the insulating paint layer is formed by coating felt with paint liquid, and the viscosity of the paint liquid is 90-150cp. In other embodiments, the insulating paint layer is formed by coating a mold with paint liquid, and the viscosity of the paint liquid is 2000-3000cp. The cross-sectional shape of the conductor is designed to allow the paint liquid of the above viscosity to be evenly coated to form the insulating paint layer.

[0033] like Figure 3a , Figure 3b , Figure 4a and Figure 4b As shown, the semi-elliptical edge 3 of the present embodiment has better leveling and heat dissipation than when the round chamfer radius r=1 / 4t and r=1 / 3t, thereby making the paint coating more uniform and the formed insulating paint layer has better uniformity; the semi-elliptical edge 3 has a better slot fill rate than when the round chamfer radius r=1 / 2t, and when the width-to-thickness ratio is 1, the special-shaped insulated wire is no longer a flat wire but a round wire when the round chamfer radius r=1 / 2t, and the special-shaped insulated wire of the present embodiment still has a higher slot fill rate; in summary, the special-shaped insulated wire of the present embodiment has better electrical properties.

[0034] The present application is further described in detail below in conjunction with specific tests.

[0035] Example 1

[0036] The thickness of the special-shaped insulated wire is 1.200 mm, the width is 2.400 mm, the short axis length of the semi-elliptical side 3 is 0.300 mm, and a polyurethane layer with a viscosity of 120 cp is used to form an insulating paint layer of 0.020±0.005 mm.

[0037] Comparative Example 1

[0038] The thickness of the special-shaped insulated wire is 1.200 mm, the width is 2.400 mm, the radius of the R portion is r=0.600 mm, and a polyurethane layer with a viscosity of 120 cp is used to form an insulating varnish layer of 0.020±0.005 mm.

[0039] Comparative Example 2

[0040] The thickness of the special-shaped insulated wire is 1.200 mm, the width is 2.400 mm, the radius of the R portion is r=0.400 mm, and a polyurethane layer with a viscosity of 120 cp is used to form an insulating varnish layer of 0.020±0.005 mm.

[0041] Comparative Example 3

[0042] The thickness of the special-shaped insulated wire is 1.200 mm, the width is 2.400 mm, the radius of the R portion is r=0.300 mm, and a polyurethane layer with a viscosity of 120 cp is used to form an insulating varnish layer of 0.020±0.005 mm.

[0043] 1. Paint uniformity test

[0044] Test method:

[0045] 1) Place the sample line vertically into a mold with a fixed pattern filled with metallographic powder and curing agent, and wait for it to be completely cured before polishing.

[0046] 2) Measure the polished metallographic section under a metallographic microscope.

[0047] 3) Calculate the eccentricity: eccentricity = maximum value of the thickness of the insulating paint layer in the cross section / minimum value of the thickness of the insulating paint layer in the cross section.

[0048] The sample lines of Example 1 and Comparative Examples 1-3 were tested using the above method. The eccentricity results are shown in Table 1:

[0049] Table 1

[0050] Eccentricity Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 1 1.173 1.300 1.428 1.041 2 1.217 1.238 1.538 1.086

[0051] It can be seen from the results in Table 1 that the eccentricity of Example 1 is the smallest and is close to 1, indicating that the paint liquid of Example 1 is applied more evenly and the formed insulating paint layer has good uniformity.

[0052] 2. Breakdown voltage performance test

[0053] The breakdown voltage performance test adopts the existing commonly used breakdown voltage test method, specifically:

[0054] 1) Cut a 500mm sample line and then use the diameter of the sample line The mandrel was bent 180° into a U shape, and both ends of the sample line were placed in a glass cup containing a 2mm steel ball, and voltage was applied for testing;

[0055] 2) Record the breakdown voltage value of the sample line.

[0056] The sample wires of Example 1 and Comparative Examples 1-3 were respectively tested for breakdown voltage performance using the above method. The test results are shown in Table 2:

[0057] Table 2

[0058]

[0059]

[0060] It can be seen from the results in Table 2 that the breakdown voltage of Example 1 is significantly greater than that of Comparative Examples 1-3, indicating that the electrical performance of the special-shaped insulated wire of Example 1 is significantly improved.

[0061] 3. Flexibility test

[0062] Test method:

[0063] Take a sample wire of about 500 mm in length and use a winding machine to perform vertical winding on the sample wire. Vertical winding means winding the long side of the flat wire perpendicular to the winding axis, bending it 180±3° into a U shape. The vertical winding inner diameters of the sample wire are 4 times, 3 times, 2 times, 1.5 times, and 1 times the wire width, respectively. Perform 10 sets of windings for each vertical winding inner diameter, and then use a 50x microscope to check whether the wire has cracks.

[0064] The sample wires of Example 1 and Comparative Examples 1-3 were tested using the above method respectively. When the sample wire of Example 1 was vertically wound, the first straight edge 1 and the second straight edge 2 were wound perpendicular to the winding axis. The test results are shown in Table 3:

[0065] Table 3

[0066]

[0067] Among them, NG means that cracks appeared in 10 groups of sample lines tested, 5 / 10 means that cracks appeared in 5 groups out of 10 groups of test sample lines, and so on.

[0068] It can be seen from the results in Table 3 that the special-shaped insulated wire of Example 1 has no cracks when the inner diameter of the vertical winding is different, and the mechanical and electrical properties are improved and more stable.

[0069] In summary, the present application designs the cross-sectional shape of the conductor so that the conductor cross-section has better leveling and heat dissipation properties, the paint coating is more uniform, the insulating paint layer has better uniformity, and the insulating paint layer is not easy to crack during winding. The design of the cross-sectional shape of the conductor also increases the slot fill rate, and the mechanical and electrical properties are improved and more stable.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement and simple improvement made to the essential content of the present invention shall be included in the protection scope of the present invention.

Claims

1. A special-shaped insulated wire, characterized in that: The invention comprises a conductor and an insulating paint layer covering the outer surface of the conductor, wherein the cross section of the conductor comprises a first straight side (1), a second straight side (2) and a semi-elliptical side (3) connecting the ends of the first straight side (1) and the second straight side (2) on the same side, wherein both ends of the first straight side (1) and the second straight side (2) are connected to the semi-elliptical side (3), and the two semi-elliptical sides (3) are arranged opposite to each other, wherein the major axis of the semi-elliptical side (3) is perpendicular to the first straight side (1) and the second straight side (2) and has a length the same as the vertical distance between the first straight side (1) and the second straight side (2), and the minor axis of the semi-elliptical side (3) is parallel to the first straight side (1) and the second straight side (2) and has a length less than 1 / 2 of the vertical distance between the first straight side (1) and the second straight side (2).

2. The special-shaped insulated wire according to claim 1, characterized in that: The length of the short axis of the semi-elliptical side (3) is 1 / 5 to 1 / 3 of the vertical distance between the first straight side (1) and the second straight side (2).

3. The special-shaped insulated wire according to claim 2, characterized in that: The length of the short axis of the semi-elliptical side (3) is 1 / 4 of the vertical distance between the first straight side (1) and the second straight side (2).

4. The special-shaped insulated wire according to claim 1, characterized in that: The sum of the lengths of the short axes of the first straight side (1) or the second straight side (2) and the two semi-elliptical sides (3) is 1 to 2 times the vertical distance between the first straight side (1) and the second straight side (2).

5. The special-shaped insulated wire according to claim 1, characterized in that: The sum of the lengths of the short axes of the first straight side (1) or the second straight side (2) and the two semi-elliptical sides (3) is 1.1-2 times the vertical distance between the first straight side (1) and the second straight side (2).

6. The special-shaped insulated wire according to any one of claims 1 to 5, characterized in that: The vertical distance between the first straight edge (1) and the second straight edge (2) is 0.500 mm-2.000 mm.

7. The special-shaped insulated wire according to claim 1, characterized in that: The conductor is copper, aluminum, copper alloy or aluminum alloy.

8. The special-shaped insulated wire according to claim 1, characterized in that: The insulating paint layer is a polyurethane layer, a polyetherimide layer, a polyimide layer or a polyamide-imide layer.

9. The special-shaped insulated wire according to claim 1 or 8, characterized in that: The insulating paint layer is formed by coating felt with paint liquid, and the viscosity of the paint liquid is 90-150cp.

10. The special-shaped insulated wire according to claim 1 or 8, characterized in that: The insulating paint layer is formed by coating a paint liquid through a mold, and the viscosity of the paint liquid is 2000-3000cp.

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