JPS60143614A - Flat air-core coil and manufacture thereof - Google Patents

Abstract

PURPOSE:To reduce intrusion to be generated in the layer of the winding start and the layer close thereto at the acute angle part of a flat air-core coil by a method wherein the inside shape of the coil wound round for the necessary number of turns is formed in a shape having the enlarged angle thereof according to a slope provided to one side of the acute angle (including a right angle). CONSTITUTION:A three layer thin belt (d) wound around a core 11 is accommodated in a jig 12, and covered with a jig 13 from the upside. After, then, the jig 13 is pressed to the jig 12 according to screws 21, external pressure is applied to the three layer thin belt (d) to mold the external shape into the necessary shape, and respective layers are bonded. At this time, although a distortion is generated to the acute angle part according to relaxation of windings and expansion at heating time, while by forming the slope of the angle theta to the beta2 side, the inside layer parts meander at the acute angle part to absorb the distortion thereof without reducing length of alpha. Accordingly, generation of strong intrusion can be checked.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a drive coil of a motor in which several trapezoidally wound coils are combined to form a drive coil, which has at least one or more acute angles (hereinafter referred to as right angles) in a part of the inner shape. The present invention relates to a flat air-core coil having corner portions (including corners) and an apparatus for manufacturing the same.

Conventional flat air-core coils of this type are most commonly made by winding an insulating coated electric wire with a circular cross section around a core of a desired shape and a desired number of turns.

However, as shown in Fig. 1, even if the winding with the fewest voids is possible, the occupancy of the conductor 1 in the cross-sectional area cannot be kept high, compared to the required number of turns. There was a drawback that the cross-sectional area became large.

That is, in FIG. 1, the radius of the wire including the insulation N2 is R.
1. If the radius of the conductor in the wire is R2, the ratio of the cross-sectional area occupied by the wire to the cross-sectional area is 3πR22/6 x 5R1
2X 100-9.0.6 9%, which is an ideal value, but in actuality the value is lower than this because spaces are created between the wires.

The space factor of the conductor 2 in the wire differs slightly depending on the wire used, but for example, the space factor of the conductor 2 is O, 17m.
The maximum finished diameter of polyurethane coated copper wire when using copper wire with a diameter of 0.214. mm, the space factor is 6
It is 9%.

Therefore, the area ratio occupied by the conductor 2 in the cross section of the coil is:
Even in the ideal case, it is 90.69% x 69% #62%, but in reality it is usually around 50X, and at best it is only 60%, and the space factor of coils used in cassette record players etc. It is about 60X.

Therefore, as shown in FIG. 2, a method has also been proposed in which an insulating coated copper wire with a circular cross section is flattened using a roll machine or the like and then wound around a core.

In this case as well, since the material of the wire is an insulating coated copper wire, the space factor of the wire itself does not change, and therefore the space factor of the conductor as a coil cannot exceed 70%.

In addition, since the insulating layer is rolled with rolls, etc., if the aspect ratio of the cross section is increased, the insulating layer will be damaged and cause a short circuit between the layers, so it is not possible to flatten the cross section too much, and the flattening ratio cannot be increased. However, since the insulation thickness is about 0.022 mm for wires with a diameter of 0.17 mm, the thickness of the conductor becomes smaller compared to the thickness including the insulation layer, resulting in a decrease in the space factor. Undesirable.

Furthermore, if the diameter of the conductor varies, this variation will be magnified and varied in the crushed wire, resulting in the width of the entire wound coil not being able to fit into the specified center gate, or the width of the magnetic circuit may be affected. In the case of a coil used as a part, the gap between the coil and the magnet partially increases, resulting in a decrease in magnetic efficiency.

Recently, printed coils have been developed in which a metal thin film is pasted on a thin insulating sheet, a predetermined pattern is printed on this thin film, or a metal thin film is left in a predetermined coil shape by photoresist treatment and etching. A method has been proposed in which a required number of insulating sheets are stacked on top of each other.

However, since this coil is formed as described above, the middle part of the metal thin film that becomes the coil requires a large dimension compared to the thickness of the thin film, as shown in FIG.
Due to the stacking of insulating sheets, it could not be used for coils that required a large number of turns.

In addition, when considering productivity, the thickness of the insulating sheet 4 is set to 0.
．． Since it is difficult to reduce the thickness to 01n or less, there remains a drawback that an improvement in the space factor cannot be expected.

In order to eliminate these conventional drawbacks, the present invention involves twisting a conductive thin strip such as copper foil, and adding an insulating layer between the wound layers to insulate the thin strip, and an insulating layer and the thin strip between the wound layers. An adhesive layer is interposed and this is cut to the required thickness to create a flat air-core coil with terminals at the beginning of the winding and at the end of the winding. This improves the space factor of the conductor, makes the coil outer shape constant, and prints the coil. The present invention provides a flat air-core coil that can flow a higher current than the conventional one.

By changing the shape of the wound core to regularize this, it is possible to reduce the bite and distortion of the inner layer of the coil that occurs at the acute angle portion of the inner shape.

In addition, by selecting the material of the winding core, it is possible to ensure the ease of extracting the core, and also to press the coil between the spacer that shapes the outer needle of the coil to achieve close contact and adhesion between the eyebrows. be.

Hereinafter, the process of manufacturing the air-core coil of the present invention using the manufacturing apparatus of the present invention will be described in detail with reference to FIGS. 5 to 12.

In the first step, a diluted epoxy resin is applied as an insulating agent onto one side of a medium-wide copper foil a using a roll coater 6.

At this time, the coating thickness is set by adjusting the doctor knife 7 attached to the roll coater 6, and after the coating is applied, it is heated and dried with a heater 8, solidified, and wound onto a winding roll 9. The thickness of the insulating material after solidification is sufficient to provide the necessary electrical insulation.

In the second step, the take-up roll 9 is suspended so that the rotation direction of the take-up roll 9 is reversed, and the m-foil a is applied to the roll coater 6 with the adhesive Jib facing upward. Apply an adhesive made of diluted polyamide thermoplastic resin to the opposite side to the adhesive side.

This is heated with a heater 8, dried and solidified, and wound onto a take-up roll 10 as an adhesive layer C. As shown in FIG. Layer C
A medium-wide three-layer ribbon d is formed.

In the third step, the three-layer thin ribbon d is wound around the trapezoidal core 11 shown in FIG. 7 for a required number of turns while applying pack tension.

Next, as a fourth step, the three-layer thin ribbon d wound around the core 11 is put into a jig 12 of a desired shape, and is strongly compressed and molded from above with a jig 13 of a desired shape. In the winding process, the material that swells toward the outer periphery and has the shape shown in Figure 8 is a process for making each one-turn layer closely adhere to the required shape with the inner and outer peripheries parallel as shown in Figure 9. It is.

In the fifth step, the molded three-layer ribbon d is placed in a jig 12.1.
3 is heated in a hot air drying oven 15 having a heater 14, and the adhesive layer C adheres to the copper foil a and the insulating layer A which was brought into close contact with each other in the fourth step by this heating and cooling.

The 6th process is the 3-layer ribbon d that has strong shape retention ability in the previous process.
The core 11 is extracted from the core 11 using a press-fitting machine.

The seventh step is a step of cutting the three-layer ribbon d from which the core 11 has been removed to a required thickness, and the wire 16 and three
Stress is applied between the wire 16 and the thin ribbon d, and the wire 16 is cut while moving back and forth.

In order to increase cutting efficiency, the three-layer ribbon d may be fixed to a glass plate or the like with an adhesive and simultaneously cut using a large number of wires.

Step 8.9.10 is a step of cleaning the abrasive grains attached to the three-layer ribbon d after the cutting, and the cleaning is carried out by ultrasonic cleaning using Triclean and Gaiflon, which do not have a negative effect on the three-layer ribbon d. Drying is performed using a hot air drying oven 19 while heating with a heater 18 at a lower temperature than in the fifth step.

The 11th step is nitric acid (HNO3), ferric chloride (FeCβ)
3) Etching is used to remove short-circuits between the eyebrows of the three-layer thin strip d due to copper powder during cutting or burrs on the material of the copper foil a. , nitric acid is used in the insulating layer b, including the post-process.
This is to prevent the adhesive layer C from being adversely affected.

The 12th and 13th steps are steps for removing the etching agent used in the previous step, and the cleaning is done by neutralizing the etching agent and then washing with water, or directly washing with water, and then drying with the heater 18.
This is carried out in a hot air drying oven 19 heated at the same temperature as in the 10th step.

The next 14th and 15th steps are insulation treatment steps for the cut end surface.
It is immersed in a bath 20 in which epoxy or polyamide is diluted and dried in a hot air drying oven 19 heated by a heater 18.

Finally, in the 16th step, the beginning and end of the three-layer ribbon d are pulled out to form a terminal.

In the fourth step of manufacturing this flat air-core coil, the three-layer thin ribbon d wound around the core 11 is housed in a jig 12 as shown in FIG. After the lid is closed, the jig 13 is pressed against the jig 12 with the screw 21 to apply external pressure to mold the three-layer thin ribbon d into a desired shape, thereby bringing each layer into close contact with each other.

At this time, if there is an acute angle in the circular shape of the coil, the inner periphery will be unwound as shown in Figure 11, as it will be subjected to the shrinkage effect due to the molding in the fourth step, the pressurization due to heating in the fifth step, and the cooling. Not only does the layer have a shape that bites into it, and there is a risk of it breaking due to the stress caused by sudden bending, but it also becomes difficult to pull out the innermost layer of the 3N thin ribbon d to make a terminal.

On the other hand, when a flat air-core coil is used as a drive coil of a motor, α of the core 11 in Fig. 7 is required for torque generation.
The three-layer thin ribbon d wound around the sides has a large influence, and the sides βl and β2 do not contribute much to the generation of torque.

In such a case, the core 11 is formed with slopes at an angle of θ, which reduces the acute angle of that portion, at both the left and right ends of the β2 side.

The material required for the core 11 is No. 3.4.
In the process, the strength is determined, and in the fifth step, the distance between the jigs 12 and 13 is determined by expansion due to heating, and in the sixth step, the cross-sectional area of the core 11 is reduced by cooling, and the three-layer ribbon d This creates a gap between the two.

Regarding the strength, if you wrap it around the core 11 without adding much back tension in the third step, you will not need the strength to harden the SK material.
Hardness comparable to that of aluminum or aluminum alloy is sufficient.

The increase or decrease in the cross-sectional area of the core 11 during heating and cooling in step 5.6 is determined by the fact that the material of the conductive ribbon a is copper, and the jigs 12, 13
Since steel is normally used for the core 11, the purpose can be achieved by using aluminum or an aluminum alloy having a higher coefficient of thermal expansion than the core 11.

By combining the materials in the 4.5th step as described above, the 3N thin ribbon d is made of core 11 and jigs 12 and 13.
The adhesion between the eyebrows is increased, and when cooled, at a temperature below the softening point of the adhesive layer of the three-layer ribbon d,
There is no fear of peeling of the adhesive layer, the glabella adhesion is maintained, and a gap is created between the three-layer ribbon d and the core 11, making the sixth step easier.

Moreover, by making the shape of the core 11 as described above,
When the 3N ribbon d is pressurized in step 4.5, distortion occurs at the sharp edges due to loosening of the winding and expansion during heating.
By forming a slope with an angle of θ on the two sides of β, α
This strain is absorbed by the inner layer meandering at the acute corner as shown in Fig.
Strong biting as shown in the figure does not occur.

In the second step, the winding roll 9 was suspended so that the rotation direction was reversed, but the adhesive layer C may be applied on the insulating material Nb with the winding roll 9 suspended in the same direction.

By doing so, it is also possible to use the same material for both.

As described above, the present invention involves winding a conductive thin strip with a thickness of about several microns, and forming an insulating layer and an adhesive layer of about 1 to several microns between the winding eyebrows, making it conductive. In addition to increasing the space factor of the body, since it is cut to a constant thickness, the outer shape is also constant, and a high-quality, high-efficiency flat air-core coil with a large ampere turn can be obtained.

Then, the material of the core used in the third step and below is
By using a material with a higher coefficient of thermal expansion than the conductive ribbon, such as aluminum or aluminum alloy, the degree of adhesion between the winding layers of the three-layer ribbon is increased, and the core can be easily removed after cooling. There is no risk of damage to the innermost layer or collapse of the winding shape, and it also leads to improved productivity.

By forming the core shape as described above, the inner layer becomes distorted at the acute angle of the inner shape, causing a wedged state, which may cause wire breakage or make it difficult to pull out the terminal. , distortion and biting can be reduced, there is no risk of wire breakage, the terminal can be easily pulled out, and the length of the side that contributes to rotational torque is not shortened, so there is no decrease in torque. .

Furthermore, the flat air-core coil formed in this way can be pulled out without damaging the terminal due to its internal shape, and the inner layer is not broken at sharp corners, so its performance is improved. It is possible to fully demonstrate this.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the space factor of a coil using a wire with a circular cross section, Figure 2 is an explanatory diagram of the cross section when the wire with a circular cross section is flattened, Figure 3 is a diagram of the coil shape, and Figure 4 5 is an explanatory cross-sectional view of a printed coil, FIG. 5 is a step 4 showing an example of the manufacturing process of the coil of the present invention, FIG. 6 is a cross-sectional view of a three-layer ribbon, and FIG. 7 is a side view of the core. Figure 8 is a side view when it is rolled up, Figure 9 is a side view when it is molded, Figure 10 is a diagram of the relationship between the core and spacer, and Figure 11.
This figure and FIG. 12 are comparative diagrams of the winding state of the three-layer ribbon when no slope is provided at the circular acute corner and when it is provided. a...Copper foil, b...Insulating layer, C...
...Adhesive layer, d...3N ribbon, 11...
... Core, 12.13 ... Spacer. Patent Applicant: Pioneer Corporation 5

Claims (1)

[Claims] (1) An insulating layer that insulates the wound thin strip and an adhesive layer that adheres the insulating layer and the thin strip are interposed between each wound layer of the conductive thin strip, and the corners of the inner shape are A rectangular shape with one or more of the acute angles (including right angles), and the inner shape of the coil wound with the required number of turns, by a slope provided on one side of the acute angle,
A rectangular air-core coil is manufactured by winding this three-layer ribbon around a core, with the angle expanded, and the beginning of the winding at the acute angle part and the biting that occurs in the layers near it, forming a light and thin ribbon. In the device, the rectangular shape has one or more acute angles (including right angles), and is made of a material having a larger coefficient of thermal expansion than the conductive ribbon, and a slope that enlarges the acute angle, A manufacturing apparatus for a flat air-core coil, characterized in that an air-core coil is manufactured using a core shaped at one side of the acute angle.