CN118299126A - Preparation method of PEEK insulating layer of multilayer thin flat wire winding - Google Patents

Abstract

A preparation method of a PEEK insulating layer of a multilayer thin flat wire winding comprises the following steps: 1) Cold rolling and annealing the copper wire; 2) Rolling a layer of self-adhesive paint on the front and back surfaces of the thin flat wire, and drying; 3) Overlapping the painted thin flat wire into a plurality of layers, placing the thin flat wire into a die, performing high-temperature and high-pressure treatment, and performing lamination forming to obtain a multilayer thin flat wire winding; 4) Drying PEEK polymer particles and then melting at a high temperature; 5) Introducing the multilayer thin flat wire winding into the melted PEEK material, and extruding the PEEK material to obtain an insulating layer on the surface of the multilayer thin flat wire winding; 6) And cooling the multi-layer thin flat wire winding with the insulating layer and then rolling. By adopting the method, the coating treatment of the winding is reduced, the extruded multilayer thin flat wire winding and the PEEK insulating layer can meet the high temperature resistance and oil resistance, and the alternating current loss caused by the skin effect is effectively reduced.

Description

A method for preparing a PEEK insulation layer of a multi-layer thin flat wire winding

Technical Field

The invention belongs to the technical field of new energy motor wire winding insulation layers, and specifically relates to a method for preparing a multi-layer thin flat wire winding PEEK insulation layer.

Background technique

In the new energy drive motor industry, motor stators generally use flat wire windings because of their advantages over round wire windings, such as high slot fill rate, high power density, low armature noise, material saving at the end, and small and light weight. As the motor speed increases, the current distribution inside the conductor becomes uneven, and the current is mainly concentrated in the thin layer on the surface of the conductor. The current inside the conductor is small, causing increased AC losses. Therefore, it is proposed to prepare multi-layer thin flat wire windings to evenly distribute the current on each conductor and reduce the AC losses caused by the skin effect.

During the operation of the motor, the motor flat wire winding will directly contact the oil, and the insulation material needs to have excellent oil resistance. PEEK insulation material has the advantages of high and low temperature resistance, stable chemical properties, oil resistance, low moisture absorption, good fluidity in the molten state, high dielectric strength, high stiffness, high tensile strength, and high thermal conductivity in the solidified state. Therefore, PEEK insulation material is used as the insulation layer of the multi-layer thin flat wire winding. The prepared multi-layer thin flat wire winding needs to meet the requirements of PDIV greater than 1350V; power frequency withstand voltage greater than 2600V, and insulation resistance greater than 20MΩ; in the oil-water mixture BOT-805C-EV (oil: deionized water = 99.8:0.2), after a cycle test of room temperature-(155℃/40h-minus 45℃/8h)×8 cycles-room temperature, the winding appearance does not bubble, crack, or the paint film does not fall off, and the PDIV is not less than 80% of the initial value.

At present, the preparation of the existing flat wire winding insulation layer usually involves primer coating and drying the flat wire, then coating and drying the intermediate layer, and finally coating the insulating varnish. This preparation method has complex procedures, and the flat wire winding needs to be coated with a coating roller many times during the production process, which may result in uneven coating and surface damage.

Summary of the invention

The purpose of the present invention is to provide a method for preparing a PEEK insulation layer of a multi-layer thin flat wire winding in view of the shortcomings of the prior art. The method of the present invention reduces the coating process of the winding, and the extruded multi-layer thin flat wire winding and PEEK insulation layer can meet the requirements of high temperature resistance and oil resistance, and effectively reduce the AC loss caused by the skin effect.

The object of the present invention is achieved in that:

A method for preparing a multi-layer thin flat wire winding PEEK insulation layer comprises the following steps:

1) cold rolling and annealing the copper wire to obtain a thin flat wire with a thickness of 0.01 to 1 mm;

2) Roll a layer of 2-8 μm self-adhesive paint on both the front and back sides of the thin flat wire and dry it;

3) Overlap 2 to 100 layers of the painted thin flat wires and place them in a mold, subjecting them to high temperature and high pressure treatment, and laminating and forming a multi-layer thin flat wire winding;

4) After drying the PEEK polymer particles, they are melted at high temperature;

5) introducing the molten PEEK material into the multi-layer thin flat wire winding and extruding it to obtain an insulating layer with a thickness of 100 to 150 μm on the surface of the multi-layer thin flat wire winding;

6) The multi-layer thin flat wire winding with the insulation layer is cooled and then rolled up.

Step 2) The self-adhesive paint is a water-based organic resin and has good compatibility with the PEEK material.

Step 3) The high temperature is 180-280° C., the high pressure is 6-8 MPa, and the treatment time is 30-60 s.

Step 4) The PEEK polymer particles are placed in an air circulation oven for drying at 150° C. for 4 to 6 hours, or at 160° C. for 3 to 4 hours, until the moisture content of the PEEK polymer particles is less than 0.02% w/w.

Step 4) The melt temperature of the PEEK polymer is maintained at 360-400°C.

The extrusion speed in step 5) is laminar flow.

Step 6) When the cooling environment temperature is lower than 5°C, natural air cooling is adopted; when the cooling environment temperature is not lower than 5°C, forced air cooling or water cooling is adopted.

Beneficial effects of the present invention:

(1) The method of the present invention adopts extrusion molding of the insulating layer, which reduces the coating process of the winding and avoids the problem of uneven coating by the coating roller and damage to the surface of the insulating layer.

(2) PEEK insulation material is used as the insulation layer of the multi-layer thin flat wire winding, which can meet the high temperature and oil resistance of the motor.

(3) The use of several layers of thin flat wires stacked together to form a multi-layer thin flat wire winding can evenly distribute the current on each conductor and reduce the AC loss caused by the skin effect.

The applicant's experiment verified that the PDIV of the multi-layer thin flat wire winding prepared by the method of the present invention is greater than 1350V; the power frequency withstand voltage is greater than 2600V, and the insulation resistance is greater than 20MΩ; in the oil-water mixture BOT-805C-EV (oil: deionized water = 99.8:0.2), after a cyclic test of room temperature-(155℃/40h-minus 45℃/8h)×8 cycles-room temperature, the winding appearance does not bubble, crack, or fall off the paint film, and the PDIV is not less than 80% of the initial value.

The multi-layer thin flat wire winding prepared by the method of the present invention can meet the high temperature resistance and oil resistance of the motor, and effectively reduce the AC loss caused by the skin effect, thereby meeting the motor operation requirements.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a flow chart of the present invention;

FIG. 2 is a schematic diagram of a multi-layer thin flat wire winding.

Description of the drawings: PEEK insulation layer 1, thin flat wire 2, self-adhesive paint layer 3.

Detailed ways

Further description is given below in conjunction with the accompanying drawings and specific implementation methods.

Thickness of the self-adhesive paint layer Thickness of insulation layer Example 1 2～3μm 100μm Example 2 5～8μm 100μm Example 3 5～8μm 150μm

Referring to FIG. 1 , according to the above embodiment, a method for preparing a PEEK insulation layer of a multi-layer thin flat wire winding includes the following steps:

1) A copper wire with a diameter of 0.178 mm is selected for cold rolling to obtain a thin flat wire with a thickness of 0.1 mm and a width of 2.5 mm, and then annealed;

2) According to the thickness of the self-adhesive paint layer of Example 1 to Example 3, a layer of CP20-375 self-adhesive paint is rolled on the front and back sides of the thin flat wire respectively, and then dried;

3) Overlap 20 layers of the painted thin flat wire and put them into a mold. The temperature is set to 180-240°C, the pressure is set to 6MPa, the processing time is 60s, and the multi-layer thin flat wire winding with a thickness of 2mm is obtained by lamination molding;

4) PEEK polymer particles are placed in an air circulation furnace, dried at 150°C for 4-6 hours, and then placed in a barrel for high temperature melting, with the melt temperature maintained at 360-400°C;

5) introducing the melted PEEK material into the multi-layer thin flat wire winding and extruding it at a laminar flow rate so that the surface of the multi-layer thin flat wire winding has the thickness of the insulation layer of Example 1 to Example 3 respectively;

6) The multi-layer thin flat wire winding with an insulating layer is cooled by forced air cooling and wound up using an automatic winding device.

The multilayer thin flat wire windings prepared in Examples 1 to 3 were subjected to insulation resistance, power frequency withstand voltage, and PDIV tests; in an oil-water mixture BOT-805C-EV (oil: deionized water = 99.8:0.2), a cycle test of room temperature-(155°C/40h-minus 45°C/8h)×8 cycles-room temperature was carried out, and the PDIV was measured again. The test results are shown in the following table:

PDIV Power frequency withstand voltage Insulation resistance PDIV after high and low temperature oil resistance test Example 1 1420V 2700V 20MΩ 1380V Example 2 1470V 2780V 21MΩ 1430V Example 3 1520V 3000V 32MΩ 1490V

Conclusion: It can be seen from the above table that the PDIV values of the multi-layer thin flat wire windings prepared in Examples 1 to 3 are all greater than 1350V, the power frequency withstand voltage is greater than 2600V, and the insulation resistance is greater than 20MΩ. After the high and low temperature oil resistance test, the appearance of the multi-layer thin flat wire winding does not bubble, crack, or fall off the paint film, and the PDIV is not less than 80% of the initial value.

The multi-layer thin flat wire winding prepared in Example 1 was subjected to a performance comparison test with a single-layer flat wire winding of the same size (2 mm thick × 2.5 mm wide). Under the same test conditions, the AC loss of the single-layer flat wire winding at 16000 rpm was 5 kW, and the AC loss of the multi-layer thin flat wire winding at 16000 rpm was 1 kW, and the AC loss was reduced by 80%. Therefore, the multi-layer thin flat wire winding prepared by the method of the present invention can meet the high temperature resistance and oil resistance of the motor, and effectively reduce the AC loss caused by the skin effect, meeting the motor operation requirements.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims (7)

1. The preparation method of the PEEK insulating layer of the multilayer thin flat wire winding is characterized by comprising the following steps of:

1) Cold rolling and annealing the copper wire to obtain a thin flat wire with the thickness of 0.01-1 mm;

2) Rolling a layer of self-adhesive paint with the thickness of 2-8 mu m on the front and back surfaces of the thin flat wire, and drying;

3) Overlapping the painted thin flat wire by 2-100 layers, placing the thin flat wire into a die, performing high-temperature and high-pressure treatment, and performing lamination forming to obtain a multilayer thin flat wire winding;

4) Drying PEEK polymer particles and then melting at a high temperature;

5) Introducing the multilayer thin flat wire winding into the melted PEEK material, and extruding the PEEK material to obtain an insulating layer with the thickness of 100-150 mu m on the surface of the multilayer thin flat wire winding;

6) And cooling the multi-layer thin flat wire winding with the insulating layer and then rolling.

2. The method of claim 1, wherein the self-adhesive paint of step 2) is an aqueous organic resin.

3. The method according to claim 1, wherein the high temperature in step 3) is 180 to 280 ℃, the high pressure is 6 to 8MPa, and the treatment time is 30 to 60s.

4. The method of claim 1, wherein the PEEK polymer particles of step 4) are dried in an air circulation oven at 150 ℃ for 4-6 hours or 160 ℃ for 3-4 hours until the PEEK polymer particles have a moisture content of less than 0.02% w/w.

5. The method of claim 1, wherein the PEEK polymer in step 4) is maintained at a melt temperature of 360-400 ℃.

6. The method of claim 1, wherein the extrusion speed of step 5) is laminar.

7. The method of claim 1, wherein step 6) is performed by natural air cooling when the cooled ambient temperature is less than 5 ℃; when the cooling ambient temperature is not lower than 5 ℃, forced air cooling or water cooling is adopted.