JPH07182943A - Insulating varnish applying method and device for enameled fine wire - Google Patents

Abstract

PURPOSE:To reduce application irregularities, unequal thickness, flatness, and the dispersion of the finished outer diameter and reduce defective appearances such as rashes and glaring by increasing varnish squeezing felt parts in the passing direction of fine wires. CONSTITUTION:Felts of all varnish squeezing felt parts 3 are dipped in the insulating varnish 2 to be used in advance, then they are set to the prescribed positions, and a bonding machine is operated. The peripheral speed of a roll 7 is finely adjusted so that the infiltration levels of the felts are made constant by the balance between the feed quantity to fine wires 1 from the coater roll 7 and the takeout quantity into a bonding furnace 4 by the fine wires 1. The fine wires 1 coated with the insulating varnish 2 proceed to the first felt part 3, they are sandwiched by the upper and lower felts in the passing process of the felt part 3, and the sticking of the varnish 2 is unified. The fine wires l passing through the first felt part 3 proceed to the second felt part 3, the stuck varnish 2 is again squeezed to the surfaces of the fine wires 1 by the felts and is further unified, and the fine wires 1 proceed to the bonding furnace 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying an insulating varnish and a coating apparatus for the insulating varnish in the baking step in the manufacturing process of an enamel electric wire. Further, the present invention relates to the production of a thin wire in which the printing machine used is a horizontal type and the insulating varnish application means is a felt diaphragm. In particular, it is highly effective when used for producing a thick film product having a wire diameter of 0.20 mm or less, especially an ultrafine wire of 0.07 mm or less.

[0002]

2. Description of the Related Art Generally, in a baking process for manufacturing an enamel electric wire, a vertical baking machine is used for a baking machine having a size larger than about 0.50 mm, and a horizontal printing machine is used for a thin cutting machine in consideration of a balance between quality and economy. A printing machine is used. And, as a means for applying the insulating varnish for applying a fixed amount of the insulating varnish, there are commonly known a die squeeze and a felt squeeze. The thinner the enamel wire, the faster the linear speed, which is the manufacturing speed. And is heavily used.

A conventional example of a felt squeeze will be described with reference to FIG. 3. After applying the insulating varnish 2 to the fine wire 1, the varnish squeeze felt portion 3 is passed through a baking furnace interior 4 in the direction of the arrow, and this is turned into a turn sheave 5. Repeatedly, the insulating layer having a desired thickness is formed. The number of repetitions is referred to as the number of times of coating, and the number of thin wires 1 that can be simultaneously manufactured per one printing machine is referred to as the number of heads or the number of multiplications.

In FIG. 3, the most general coating method is shown. In the insulating varnish 2, the coater roll 7 having a large number of V-shaped grooves 6 (see FIG. 1) on the peripheral surface of the cylindrical body is as shown by the arrow. By rotating the insulating varnish 2 at a constant speed,
The insulating varnish 2 is applied to the thin wire 1 that slides in the V-shaped groove 6, the insulating varnish 2 is leveled on the surface of the thin wire 1 at the varnish drawing felt portion 3, and the application amount is adjusted. The coater roll 7 may be rotated in the direction opposite to the arrow, and a roll without the V-shaped groove 6 is also used. Further, 8 is a pressing felt for preventing the fine wire 1 from departing from the inside of the V-shaped groove 6, although it is not always necessary. 9 applies clamping pressure to the thin wire 1 together with the varnish drawing felt part 3,
Further, it is a weight plate for suppressing the sliding of the felt. In any case, according to the conventional felt drawing method, the insulating varnish 2
The fine wire 1 coated with was only passed through one varnish drawing felt portion 3 before entering the inside of the baking furnace 4, and thereafter, the number of coating times was similarly repeated.

[0005]

Generally, in the baking process, when setting the manufacturing conditions, if the baking temperature condition is constant, the value obtained by multiplying the wire diameter of the wire to be manufactured by the wire speed is constant. The relational expression that there is is used. Therefore, the thinner the electric wire, the faster the linear velocity. Further, in order to reduce the cost, it is necessary to increase the linear velocity and increase the number of heads in the printing machine per machine. However, even if the baking conditions for forming the insulating film are correct, if the linear velocity is increased, the skin of the thin wire 1 is likely to be rough such as uneven coating and spots (small projections). For this reason, the insulating varnish 2 is used by diluting it in order to improve the so-called coating, but a coating called "glare" tends to form wavy unevenness in the length direction. Moreover, since the insulating varnish 2 is diluted, the amount of application per application is naturally reduced. Since the predetermined film thickness cannot be obtained unless the number of coatings is increased, the linear velocity is increased in order to prevent the cost increase due to the reduction in the number of heads. That is,
These are a vicious circle. Although these are related to the concentration and viscosity of the insulating varnish 2, they are always the biggest problems to be solved as defective appearance. In particular, the occurrence of uneven coating causes an extremely thin portion in a part of the film, which is likely to cause a serious defect.

[0006] In addition, for an insulating film layer having a particularly thick thickness, and an ultrafine wire having a thickness of 0.07 mm or less, the number of times of application of one thin wire 1 to be manufactured is large for the above reason. For example, 2UEW of polyurethane copper wire that is often used as extra fine wire
In that case, it is usually possible to obtain a predetermined film thickness by applying 4 to 6 times, but from 1 UEW of thick insulation layer to 0 UEW, from 10 UEW
If it is not applied 20 times, it is not possible to obtain a film thickness with good appearance. This is even more the case with other types of insulating varnish 2 having poor adhesion.

Further, when the number of times of application increases, the film is not formed into a perfect circle and is easily formed into a flat or uneven thickness.
Naturally, the degree of disconnection also increases. If the wire breaks, the thin wire 1 traveling next to the wire will also be broken, and the amount of heat absorbed by the thin wire 1 will be left over. The thin wire 1 therein is overheated, which adversely affects the electrical characteristics of the insulating layer. Moreover, as a matter of course, since the number of times of application is large, much work is required for the original repair work.

[0008] Since the furnace opening width of the baking machine is fixed, the thin film 1 having a thin film and the thin wire 1 having a large film are manufactured by the same baking machine. This means that the number of heads must be reduced as compared with the case where the thin thin wire 1 is manufactured, and the cost is increased accordingly. It is easy to understand this by comparing, as an example, 2UEW and 1UEW, which are polyurethane copper wires having a conductor diameter of 0.04 mm, by the film thickness per one time. The following table shows a conventional example in which an average number of times of application when a product of this size is manufactured with a good appearance. Looking at this table, although 1UEW has a large finishing outer diameter, it is necessary to apply twice and a half times as many times as 2UEW, because the film thickness is only about half that of 2UEW. .

[0009]

[Table 1]

Considering here, as long as the same insulating varnish is used, even if the thickness of the coating per application is as thick as 2 UEW, the electrical characteristics of the obtained insulating coating per degree are the same. It should be. In other words, as long as it does not cause a poor appearance, the thickness of the coating can be made as thin as 2UEW even with a thin wire of thick coating, and as a result, the number of coatings can be reduced and the number of heads can be increased accordingly. It should be possible. This invention, together with this cost reduction measure,
The purpose of the invention is to eliminate the above-mentioned uneven application of paint and defective appearance such as spots and glare.

[0011]

First, the insulating varnish coating method of the present invention will be described with reference to FIG. Fine line 1
In the conventional method for manufacturing an enamel thin wire, after applying the insulating varnish 2 to the varnish, passing it through the varnish drawing felt part 3 and passing through the baking furnace 4, and repeating this repeatedly to form an insulating layer of a desired thickness. A varnish drawing felt part 3 through which a thin wire 1 coated with an insulating varnish 2 passes through a manufacturing apparatus.
Are arranged in at least two places in the passing direction.

While the fine wire 1 is running, all the felts of the varnish drawing felt portion 3 are supplied to the running fine wire 1 by the insulating varnish 2 being used, so that the insulating varnish 2 is always supplied. It is a method for applying an insulating varnish for an enamel fine wire, which is characterized in that it is infiltrated in a constant state by

It is not necessary to specify the means for maintaining the felt infiltrating property of the varnishing felt portion 3.
As far as the felt of the varnish drawing felt part 3 (hereinafter referred to as the last varnish drawing felt part) closest to the arranged baking furnace 4 is infiltrated in a constant state,
Insulation varnish 2 to fine wire 1 that enters the felting part 3 for drawing on the coater roll 7 side (hereinafter referred to as the first felting part for drawing)
Can be supplied. That is, although not shown in the drawings, a method of directly supplying the insulating varnish 2 to the first varnish drawing felt portion 3 without using the coater roll 7 and adopting a fine supply pump may be used, or as shown in the drawing. It is also possible to supply by rotating the coater roll 7. The latter is generally easier to adjust the supply.

Next, the insulating varnish coating apparatus of the present invention will be described with reference to FIGS. 1 and 2. Insulation varnish 2 on thin wire 1
In the manufacturing device for the enamel thin wire, which is formed by passing through the varnishing felt portion 3 and then passing through the baking furnace 4 and repeatedly repeating this to form an insulating layer having a desired thickness,
An varnish applicator for an enamel thin wire, characterized in that at least two or more varnish drawing felt parts (3) through which the thin wire (1) coated with the insulating varnish (2) passes are provided in the passing direction. In the above, the varnish squeezing felt part 3 is provided at two or more locations, but it is difficult to maintain the third location at a constant swelling property for a long period of time due to the influence of the furnace temperature and the degree of squeezing at the preceding stage. Caution is required when there are three or more locations.

It should be noted that two felts of the varnish squeezing felt portion 3 having a rectangular shape which is commonly used are combined, and one felt having a rectangular shape as shown in FIG. The required number of cut lines 10 may be inserted in the running direction of the fine wire 1 up to the middle of the felt thickness, and the fine wire 1 may be sandwiched in the cut line 10 for running. In this case, a normal two-sheet felt may be used as the first diaphragm felt portion, and a slit line 10 may be formed as the second diaphragm felt portion, or vice versa.

[0016]

In the following description, the coater roll 7 shown in the figure is used as the supply means for the insulating varnish 2 and the varnish drawing felt portion 3 is also provided at two locations. First, all the felts of the varnish drawing felt portion 3 are dipped in the insulating varnish 2 to be used in advance, then they are set at predetermined positions, and the printing machine is operated. Naturally, the peripheral speed of the coater roll 7 is finely adjusted so that the degree of infiltration of each felt is kept constant by the balance between the amount of supply from the coater roll 7 to the thin wire 1 and the amount of the thin wire 1 carried into the baking furnace. To do.

The operation of the present invention is considered that the insulating varnish 2 supplied to the thin wire 1 goes through the following process. 1) The insulating varnish 2 supplied to the thin wire 1 by the coater roll 7 adheres only to the surface of the thin wire 1 in contact with the coater roll 7, and does not easily adhere to the entire peripheral surface. In particular, it is difficult to reach the upper surface portion and flows toward the first varnish drawing felt portion 3 while flowing downward due to gravity. 2) During the passage of the first varnish drawing felt part 3, the felt is sandwiched between the upper and lower felts and leveled so as to adhere to the upper surface part of the fine wire 1. 3) The insulating varnish 2 that has been discharged into the air from the first varnish squeezing felt portion 3 and has been leveled has the coating applied to the surface of the fine wire 1 averaged by gravity or surface tension, while the second varnish is squeezed. Head to the felt section 3. 4) The insulating varnish 2 reattached here in the second varnish drawing felt portion 3 is pressed against the surface of the thin wire 1 by the felt, and is further uniformized and surely attached. 5) Go out into the air from the second varnish drawing felt part 3 and proceed to the inside of the baking furnace 4.

In the above, 1) to 3) are the same as in the conventional case, and in the conventional case, the film was formed by leaving 3) and immediately proceeding to the inside of the baking furnace 4. In the present invention, there is a second varnish drawing felt part 3 which is spaced apart from the first varnish drawing felt part 3 so that the coating can be made more uniform. This is similar to the way a good painter uses a brush to spread the paint and top it off. If it is desired to increase the coating amount per one time, that is, the film thickness, the peripheral speed of the coater roll 7 may be increased in advance in advance. Then, a large amount of the insulating varnish 2 is supplied to the thin wire 1, so that the film thickness per application is also large.

[0019]

[Example] For a copper wire having a conductor diameter of 0.04 mm, the diameter of the coater roll 7 as shown in FIG.
mm, the felt part 3 for varnish drawing has two places, and all felts (manufactured by Marushin Felt Textile Co., Ltd.) of the felt part 3 for varnish drawing are applied with a thickness of 3 mm and a width through which the fine wire 1 passes 20 mm. The weight of the weight plate is 30g at 8 times of 5mm.
The coating device has a distance of 40 mm between the first varnish drawing felt part 3 and the second varnish drawing felt part 3. Insulation varnish 2 WD4303B with a non-volatile content of 26% (manufactured by Hitachi Chemical Co., Ltd.) was used at a viscosity of about 0.6 dPa · s. The baking conditions were 4 temperatures in the baking furnace at the inlet 280 ° C and the outlet.
It was manufactured at 340 ° C. at a linear velocity of 300 m / min. Also,
Table 2 shows the comparison with the conventional example of 15 times coating manufactured under the same manufacturing apparatus, the same insulating varnish 2 and the same baking conditions, in terms of the film thickness per coating.

[0020]

[Table 2]

From the above table, the peripheral speed of the coater roll is 20%
It can be seen that the film thickness per application is almost doubled by just increasing the amount, and the number of applications is almost halved. As shown in Table 1, this is similar to a film thickness of 0.000833 mm, which is about the same as 2 UEW. This is
The formed insulating film is the same as 2UEW, which means that there is no problem in electrical characteristics even if the number of times of coating is reduced. The following table shows the comparison of the inspection results. The number of samples in Tables 3 and 4 is
The result is 50 bobbins each. The numerical values in Table 3 show only the average value, and Table 4 shows the degree of variation. The breakdown voltage is shown by the cylinder method, the pulse breakdown voltage is shown by the time until breakdown at a frequency of 15.75 Hz and a voltage of 900 V, and other inspection items are in accordance with JIS. Further, although the description of the standard value is omitted, even the value of the comparatively low embodiment far exceeds the standard value.

[0022]

[Table 3]

[0023]

[Table 4]

According to Table 3, regarding voltage-related items,
The average values of all of these average values are superior to those of the examples, but the variation is shown in Table 4, and it is found that the examples are all smaller. In particular, the dimensional variation of the insulating film is obviously small. Therefore, as mentioned above, 2U per application
Regarding obtaining the same coating thickness as in EW manufacturing,
Regarding the dielectric breakdown voltage, the average value of the dielectric breakdown voltage per one coating is compared again. It is shown in Table 5 together with 2UEW0.04 mm, but it can be seen that the value of Example is close to 2UEW and is more excellent, and that the value of Conventional Example is as low as about half that of Example.

[0025]

[Table 5]

Returning to the drawings, the weight of the weight plate 9 varies depending on the wire diameter to be manufactured, but before and after the size of the embodiment, a metal plate of about 4 g per application may be used. In addition, if the distance between the first varnish drawing felt part 3 and the second varnish drawing felt part 3 is too long, the felt infiltration property of the second varnish drawing felt part 3 may be impaired. Be careful. On the other hand, if the interval is too short, the linear velocity is high, and the effect was small. In addition, it is possible to provide the third or more varnish drawing felt parts 3 by shortening the passing length of the thin wire 1 of each felt and also shortening the interval between the varnish drawing felt parts 3. Needless to say.

The results of wire diameters thicker than those in the above-described embodiment also yielded substantially the same effect, and therefore description thereof is omitted. Although the data is omitted, it is a conventional method using only the first varnish drawing felt part 3 and the felt width through which the fine wire 1 passes is significantly increased to 2 to 3 times the conventional length. However, the effect of the present invention was not obtained.

The type of enamel wire differs depending on the type of the insulating varnish 2. Then, depending on the type of the insulating varnish 2, the ease of applying the fine wire 1 in the baking process,
There is also a difference in how easy it is to paint. For example, among the special polyurethane varnishes that suppress outgassing,
The flow of varnish is poor, and uneven coating, flatness and uneven thickness are likely to occur. As described above, the unevenness of coating causes a thin portion of the film partially, and this does not mean that the entire circumference becomes thin over a certain length of the thin wire 1, but that a part of the circumferential surface has a short length. It occurs with a certain size. Naturally, the place tends to be a place where the electrical characteristics cannot be satisfied, and it is extremely troublesome because it is difficult to identify the place where the occurrence occurs.

The inventor has found that this kind of enamel wire has 0.03 to 0.
07 was manufactured and the number of spots where uneven paint was generated was investigated carefully along with the length of the conventional method. The investigation method is pinhole inspection, selecting the location of the breakdown voltage in water,
The unevenness of coating was identified with an electron microscope. As a result, the number of occurrences was clearly reduced, and even if it occurred, the size itself became small.

It should be noted that, in the case of this type of enameled wire having a size of 0.10 mm or more, the flatness of 0.001 to 0.004 mm has been apt to occur in the past, but according to the coating method of the present invention similar to the above-mentioned 1UEW 0.04 mm, The occurrence of
Even if it was flat, it contracted and stabilized within 0.001 mm to 0.002 mm.

The shape of the felt is necessarily rectangular due to its use. Since the first varnish drawing felt part 3 is sandwiched with respect to the thin wire 1 from the vertical direction,
Since I want to apply it to a perfect circle as much as possible, I want to change the holding direction of the second varnish drawing felt part 3 from the previous stage.
As shown in FIG. 4, as a means for this, two weight plates 11 having sawtooth-shaped cross sections are used, and two thinly cut felts 12 are sandwiched between them to alternate the sandwiching direction. To
It is possible to change it to 45 degrees. However, since FIG. 4 is an enlarged drawing and it is necessary to make it small in reality, it seems to be very unwieldy and not practical.

Therefore, as shown in FIG. 5, a parallel line-shaped cut line 10 is inserted from one side of the thick felt to halfway,
The thin wire 1 may be inserted into the cut line 10. However, the thin line such as 0.04 mm mentioned above is notched 10
When inserting it or replacing the felt, it is not practical because the long fibers obstruct it, but it is possible with a size of 0.10 mm or more. When it was carried out in combination with this felt, the same effect as that of the above-mentioned embodiment was obtained, but no more remarkable effect was obtained.

[0033]

EFFECTS OF THE INVENTION A very simple and inexpensive device for increasing the number of felt parts 3 for varnish drawing in a horizontal printing machine in the passing direction of the thin wire 1 has a serious defect of uneven coating, uneven thickness and flatness, and finishing outer diameter. It is possible to reduce unevenness of the product, and also to reduce appearance defects such as spots and glare. Further, since the number of times of application can be reduced, the number of heads in the printing machine can be increased, the cost in the printing process can be significantly reduced, the degree of wire breakage is small, and even if the wire breaks, there is an adverse effect on other thin wires 1 running. This is an industrially very useful invention in that the size becomes smaller and the repair work becomes easier.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a side view for explaining a partial cross section showing only a main part in the embodiment of the present invention.

FIG. 3 is a side view for explaining a partial cross-section showing only a main part in a conventional example.

FIG. 4 is a front view of an example of the felt portion for varnish drawing used in the present invention.

FIG. 5 is a perspective view of an embodiment of a felt used in the felt portion for varnish drawing of the present invention.

[Explanation of symbols]

 1 Fine wire 2 Insulation varnish 3 Felt part for varnish drawing 4 Inside baking oven 7 Coater roll 10 Cut line

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01B 7/02 A

Claims (3)

[Claims] 1. A thin wire (1) is coated with an insulating varnish (2), then passed through a varnish drawing felt part (3) and then passed through a baking furnace (4), which is repeatedly repeated to obtain a desired thickness. In the method for producing an enamel thin wire for forming an insulating layer, at least two or more varnish drawing felt parts (3) through which the thin wire (1) coated with the insulating varnish (2) passes are provided in the passing direction, and While the thin wire (1) is running, the felt of the felt part (3) for squeezing all the varnish is always supplied to the thin wire (1) while the insulating varnish (2) is running, so that the insulating varnish ( 2) A method of applying an insulating varnish for fine enamel wire, which is characterized by infiltrating in a constant state by 2. After applying the insulating varnish (2) to the thin wire (1), the fine varnish is passed through the felt part (3) for squeezing the varnish and then passed through the baking furnace (4). In the enamel thin wire manufacturing device for forming the insulating layer, at least two or more varnish drawing felt parts (3) through which the thin wire (1) coated with the insulating varnish (2) passes are provided in the passing direction. An insulating varnish coating device for fine enamel wire. 3. A varnishing felt part (3) having two felts of rectangular shape combined, and one rectangular felt having a cut line (10) in the running direction of the thin wire (1). The varnish coating device for fine enamel wire according to claim 2, which is used in combination with a thin wire (1) sandwiched therein for running.