Enameled wire with long service life

Abstract

The utility model discloses an enameled wire with long service life, which comprises a copper flat wire, fillets are arranged on the edges of the copper flat wire, a glass fiber wire coating layer, an inner insulating layer and an outer insulating layer are sequentially arranged on the outer side of the copper flat wire, and four self-adhesive repair tapes are arranged between the inner insulating layer and the outer insulating layer. The four self-adhesive repair tapes respectively wrap the four arc surfaces of the inner insulating layer, grooves into which the outer insulating layer is embedded are formed between the adjacent self-adhesive repair tapes, and stress release grooves corresponding to the grooves are formed in the four outer peripheral surfaces of the outer insulating layer; the inner insulating layer is formed by a glass fiber bundle spirally wound on the outer side of the copper flat wire, the glass fiber bundle is formed by stranding and twisting a plurality of glass fiber filaments, and the spiral pitch of the glass fiber bundle is 1.5-2 times of the diameter of the glass fiber bundle, so that a spiral channel is formed in the inner insulating layer.

Description

Technical Field

[0001] The utility model belongs to the field of enameled wires used in new energy vehicle hub motors, and in particular relates to an enameled wire with a long service life. Background Art

[0002] New energy vehicle batteries serve as the energy source, converting electrical energy into mechanical energy through in-wheel motors to propel the vehicle. Due to the heavy weight and high drive power of new energy vehicles, the in-wheel motors require a high current to meet the vehicle's needs. Therefore, the enameled wire in the in-wheel motors is relatively thick, typically exceeding 16 square millimeters.

[0003] From the perspective of improving motor efficiency, the larger the slot fill rate of the hub motor, the better. Therefore, most of the enameled wires used in hub motors are currently enameled copper flat wires. However, in actual use, it is found that the copper flat wires on the inside of the enameled copper flat wires are formed by drawing, and there is a large amount of drawing stress at the edges. Even after annealing, it can only be reduced but not completely removed. Similarly, the paint film on the outside of the enameled copper flat wire will also have residual stress after coating and drying, which is also mainly concentrated at the edges, forming a stress superposition.

[0004] The minimum design lifespan requirement for new energy vehicles is 10 years, placing high demands on the service life of enameled wire. However, existing enameled wire, due to its rectangular interface, is tightly stacked after being wound in the in-wheel motor, leaving almost no space. Thermal expansion compresses the wires, creating significant compressive stress and facilitating stress release. Furthermore, the vibrations of the vehicle on uneven roads also trigger stress release, which can easily break the paint film and cause problems such as short circuits in the wire, shortening its service life. Utility Model Content

[0005] The purpose of the utility model is to provide an enameled wire with a long service life. The utility model has the advantages.

[0006] The technical solution of the utility model is: a long-service-life enameled wire, comprising a copper flat wire, the edges of which are provided with rounded corners, the outer side of the copper flat wire being provided with a glass fiber coating layer, an inner insulating layer and an outer insulating layer in sequence, four self-adhesive repair tapes being provided between the inner insulating layer and the outer insulating layer, the four self-adhesive repair tapes respectively wrapping the four arc surfaces of the inner insulating layer, grooves embedded in the outer insulating layer being formed between adjacent self-adhesive repair tapes, and stress relief grooves corresponding to the grooves being formed on the four outer peripheral surfaces of the outer insulating layer.

[0007] In the aforementioned long-life enameled wire, the glass fiber coating is formed by a glass fiber bundle spirally wound on the outside of the copper flat wire. The glass fiber bundle is formed by twisting multiple glass fiber strands. The spiral pitch of the glass fiber bundle is 1.5-2 times the diameter of the glass fiber bundle, so that a spiral channel is formed on the inner insulating layer.

[0008] In the aforementioned enameled wire with a long service life, the glass fiber bundle is formed by plying and twisting 5 to 8 glass fiber filaments with a diameter of 10 to 20 microns.

[0009] In the aforementioned enameled wire with long service life, the inner side of the inner insulating layer is embedded in the channel.

[0010] In the aforementioned enameled wire with a long service life, the material of the inner insulating layer is polyesterimide varnish.

[0011] In the aforementioned enameled wire with a long service life, the material of the outer insulating layer is polyamide-imide varnish.

[0012] In the aforementioned enameled wire with a long service life, the self-adhesive repair tape is made of polyamide self-adhesive paint.

[0013] Compared with the prior art, in the present invention, the paint film that plays a role in insulation protection is mainly composed of an inner insulating layer and an outer insulating layer. The inner insulating layer has good electrical properties and high structural strength, while the outer insulating layer has a certain degree of elasticity. By providing a glass fiber coating layer on the outside of the copper flat wire, the structural strength of the inner insulating layer, which already has good structural strength, is further increased, resisting stress released from the inside to the outside, avoiding paint film breakage, and improving the service life of the enameled wire. A self-adhesive repair tape is provided between the inner and outer insulating layers, corresponding to the arc surface. That is, a self-adhesive repair tape is provided in the stress concentration area. When the paint film is impacted by stress and cracks occur, the self-adhesive repair tape is used to repair it in time, further improving the service life of the enameled wire. At the same time, after providing the self-adhesive repair tape, a stress relief groove can be formed on the outside of the enameled wire. When the enameled wire is wound in the hub motor, a certain avoidance space is formed between adjacent enameled wires, achieving stress release, avoiding paint film breakage, and improving the service life of the enameled wire. Furthermore, since the glass fiber coating is composed of spiral glass fiber bundles, the bending of the enameled wire is not affected, and the flexibility of the enameled wire is kept good, which is beneficial for subsequent winding operations. Therefore, the utility model has the advantage of a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional schematic diagram of the present utility model.

[0015] Figure 2 It is a schematic diagram of the structure of the glass fiber coating layer (the fiber bundle is thickened).

[0016] Figure 3 is a schematic cross-sectional view of a glass fiber bundle.

[0017] The markings in the accompanying drawings are: 1-copper flat wire, 2-rounded corner, 3-glass fiber coating, 4-inner insulation layer, 5-self-adhesive repair tape, 6-groove, 7-outer insulation layer, 8-stress relief groove, 30-glass fiber bundle, 31-glass fiber yarn, 32-channel. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0019] Example. A long-life enameled wire, such as Figure 1 As shown, it includes a copper flat wire 1, the copper flat wire 1 has a thickness of 3.5 mm and a width of 6 mm. A fillet 2 with a radius of 0.5 mm is provided on the edge of the copper flat wire 1. A glass fiber coating layer 3, an inner insulating layer 4 and an outer insulating layer 7 are provided on the outer side of the copper flat wire 1 in sequence. Four self-adhesive repair tapes 5 are provided between the inner insulating layer 4 and the outer insulating layer 7. The four self-adhesive repair tapes 5 respectively wrap the four arc surfaces of the inner insulating layer 4. A groove 6 embedded in the outer insulating layer 7 is formed between adjacent self-adhesive repair tapes 5, and stress relief grooves 8 corresponding to the grooves 6 are formed on the four outer peripheral surfaces of the outer insulating layer 7.

[0020] The glass fiber coating layer 3 is formed by a glass fiber bundle 30 spirally wound on the outside of the copper flat wire 1. The glass fiber bundle 30 is formed by twisting multiple glass fiber filaments 31 together. The spiral pitch of the glass fiber bundle 30 is 1.5-2 times the diameter of the glass fiber bundle 30, so that a spiral channel 32 is formed on the inner insulating layer 4.

[0021] The glass fiber bundle 30 is formed by twisting six glass fiber filaments 31 with a diameter of 15 microns.

[0022] The inner side of the inner insulating layer 4 is embedded in the channel 32 .

[0023] The inner insulating layer 4 is made of polyamide-imide varnish.

[0024] The outer insulating layer 7 is made of polyester imide paint.

[0025] The material of the self-adhesive repair tape 5 is polyamide self-adhesive paint.

[0026] The production method is as follows: after the copper rectangular wire 1 is annealed to eliminate most of the stress, it is first wound with a glass fiber bundle 30 to obtain a glass fiber coating 3, and a channel 32 is formed on the glass fiber coating 3.

[0027] Two more coats of polyamide-imide varnish are applied to form the inner insulating layer 4. The first coat of polyamide-imide varnish fills the channels 32, smoothing the outer surface of the glass fiber sheath 3. The second coat, after leveling, further smoothes the outer surface of the inner insulating layer 4 and increases the insulation thickness. The inner insulating layer 4 serves two purposes: first, to form the first insulating protective layer; second, to prevent axial slippage of the glass fiber bundles 30, thereby providing a firm shape. Furthermore, the glass fiber bundles 30 act as a skeleton for the inner insulating layer 4, increasing its strength and providing better resistance to stress and shock.

[0028] Then, polyamide self-adhesive paint is applied to the corresponding edge positions to form four self-adhesive repair strips 5. The polyamide self-adhesive paint can be applied in two or more coats to obtain a thicker paint layer, or it can be refrigerated at a lower temperature to reduce its temperature and fluidity before applying it in a single coat to obtain a thicker paint layer. The paint layer thickness is preferably about 0.1 mm, resulting in a depth of about 0.1 mm for the grooves 6.

[0029] Finally, polyesterimide paint is applied to obtain the outer insulating layer 7.

[0030] Working principle: In terms of electrical performance, including high temperature resistance and corona resistance, polyamide-imide paint is superior to polyester-imide paint, but the price is also much higher. However, in terms of flexibility, polyester-imide paint is superior to polyamide-imide paint. The utility model combines polyamide-imide paint and polyester-imide paint. The polyamide-imide paint with better electrical performance is set on the inner side, which can improve the electrical performance of the enameled wire; the polyester-imide paint with better flexibility is set on the outer side, which can better withstand the bending stress of the enameled wire and has a certain elasticity on the outer side of the enameled wire. At the same time, it also reduces the amount of polyamide-imide paint used and reduces the cost of the enameled wire. The glass fiber bundle 10 is spirally wound on the copper flat wire 1, which can not only comprehensively enhance the strength of the inner insulation layer and enhance its ability to withstand stress, but also basically has no effect on the bending and winding of the enameled wire, making it convenient to use the enameled wire. In the stress release area and the edge, the utility model is provided with a self-adhesive repair tape 5. The self-adhesive repair tape can not only form a stress release groove 8 on the outer peripheral surface of the enameled wire to improve the heat dissipation performance, but also can repair the paint film when it is broken, thereby increasing the service life of the enameled wire and reducing the failure rate of the hub motor.

[0031] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

Claims

1. An enameled wire with a long service life, characterized by: The invention comprises a copper flat wire (1), wherein a rounded corner (2) is provided on the edge of the copper flat wire (1), a glass fiber coating layer (3), an inner insulating layer (4) and an outer insulating layer (7) are sequentially provided on the outer side of the copper flat wire (1), four self-adhesive repair tapes (5) are provided between the inner insulating layer (4) and the outer insulating layer (7), the four self-adhesive repair tapes (5) respectively wrap four arc surfaces of the inner insulating layer (4), grooves (6) embedded in the outer insulating layer (7) are formed between adjacent self-adhesive repair tapes (5), and stress release grooves (8) corresponding to the grooves (6) are formed on the four outer peripheral surfaces of the outer insulating layer (7).

2. The long-life enameled wire according to claim 1, characterized in that: The glass fiber coating layer (3) is formed by a glass fiber bundle (30) spirally wound on the outside of the copper flat wire (1). The glass fiber bundle (30) is formed by twisting a plurality of glass fiber filaments (31). The helical pitch of the glass fiber bundle (30) is 1.5-2 times the diameter of the glass fiber bundle (30), so that a spiral channel (32) is formed on the inner insulating layer (4).

3. The long-life enameled wire according to claim 2, characterized in that: The glass fiber bundle (30) is formed by plying and twisting 5 to 8 glass fiber filaments (31) with a diameter of 10 to 20 microns.

4. The long-life enameled wire according to claim 2 or 3, characterized in that: The inner side of the inner insulating layer (4) is embedded in the channel (32).

5. The enameled wire with a long service life according to claim 1, characterized in that: The material of the inner insulating layer (4) is polyester imide paint.

6. The enameled wire with a long service life according to claim 1, characterized in that: The material of the outer insulating layer (7) is polyamide-imide paint.

7. The enameled wire with a long service life according to claim 1, characterized in that: The material of the self-adhesive repair tape (5) is polyamide self-adhesive paint.

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