Varnish application mechanism, enameled wire manufacturing apparatus, and enameled wire manufacturing method

Abstract

To provide a varnish application mechanism capable of inhibiting occurrence of an uneven thickness of an insulation layer by uniformly applying varnish to a conductor even if a pass line is changed.SOLUTION: A varnish application mechanism for applying varnish while causing a conductor to travel is disclosed. The varnish application mechanism includes: a correction valve that corrects a pass line of the conductor upon receipt of supply of varnish; and an application die which is disposed downstream of the correction valve in a travelling direction of varnish in a state of being away from the correction valve, and which controls an amount of application of varnish to the conductor.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] The present invention relates to a varnish coating mechanism for applying varnish to a conductor, and an enameled wire manufacturing apparatus and manufacturing method including the mechanism.

Background Art

[0002] Conventionally, varnish has been applied while running a conductor, and then the varnish has been baked to manufacture enameled wire. Patent Document 1 discloses a horizontal enameled wire manufacturing apparatus, and provides a coating die capable of forming a uniform coating film. In particular, in Patent Document 1, a die chip (4) is installed at the lead-out portion of the case (3), and a second die chip (5) is installed at the lead-in portion, and the supply amount of varnish to the die chip (4) is regulated and controlled by the second die chip (5). The die chip (4) applies varnish to the conductor while stabilizing the supply amount of varnish, and as a result, attempts to form a uniform coating film. In a vertical enameled wire manufacturing apparatus, the die is floated and follows the shaking of the conductor to reduce eccentricity. In the horizontal type, there is a coating apparatus having a structure in which the angle with respect to the fulcrum of the die can be changed following the vertical type, and eccentricity reduction and die adjustment can be easily performed, aiming to shorten the adjustment time.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a horizontal enameled wire manufacturing apparatus, generally, it is necessary to consider the "catenary curve (curve drawn by the conductor hanging with both ends of the conductor)" of the conductor, and it is difficult to align the pass line. As a result, it is difficult to uniformly apply varnish to the conductor, and suppressing the occurrence of eccentricity in the insulating layer has become an immediate problem. In a conventional horizontal enameled wire manufacturing apparatus, the furnace length of the conductor (the furnace length of the baking furnace) was short, and the conductor tended to be supported by sheaves and run. However, in recent horizontal enameled wire manufacturing apparatuses, in order to achieve a high wire speed of the conductor in accordance with the requirement of improving the productivity of the enameled wire, the furnace length has been increasing to increase the amount of heat applied to the conductor. Therefore, the distance (span) between the sheaves tends to be long, the influence of the catenary of the conductor is large, it is difficult to suppress the vibration of the conductor, and as a result, it is difficult to specify the pass line of the conductor, and suppressing the occurrence of uneven thickness of the insulating layer has become a major issue. Even if the technology of Patent Document 1 is used to solve such a problem, in this technology, in a state where the positional relationship between the die chip (4) and the second die chip (5) is fixed, the arrangement of these members is matched with the pass line of the conductor to form a uniform coating film. Therefore, in a situation where the pass line of the conductor is unstable and it is difficult to specify it, uneven thickness of the insulating layer cannot be suppressed.

[0005] Also, in the case of a vertical enameled wire manufacturing apparatus, when floating the die, there is a concern that it may not be able to sufficiently follow in a place where the shaking changes greatly. In the case of a horizontal type, when providing a fulcrum for the die and rotating it freely, since it is considered that the position of the fulcrum is on the pass line, the accuracy of centering on the pass line becomes important. The change in the pass line is not only a relatively short-term change due to vibration and shaking, but also the influence of the slow temperature change of the furnace body itself until the baking furnace reaches an equilibrium state (long-term change), and the catenary curve changes along with the tension change when the speed of the conductor is changed or a speed fluctuation occurs. Thus, there are many factors that cause the catenary curve to change in the manufacturing process of enameled wire.

[0006] The main object of the present invention is to provide a varnish coating mechanism that can uniformly apply varnish to a conductor even when the pass line fluctuates and suppress the occurrence of uneven thickness of the insulating layer.

Means for Solving the Problem

[0007] According to the present invention, in order to solve the above problems, a varnish coating mechanism for coating a varnish while running a conductor, a correction valve that corrects the position of the path line of the conductor before receiving the supply of the varnish, a coating die that is arranged downstream of the correction valve in the running direction of the varnish while being separated from the correction valve, and controls the coating amount of the varnish on the conductor, A varnish coating mechanism is provided, which is characterized by comprising the above.

Advantages of the Invention

[0008] According to the present invention, by providing means for suppressing fluctuations in the path line in front of the coating die, fluctuations in the path line can be suppressed, so that the varnish can be uniformly applied to the conductor and the occurrence of uneven thickness of the insulating layer can be suppressed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2A

Figure 2B

Figure 2C

Figure 3A

Figure 3B

Figure 3C

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an enameled wire manufacturing apparatus, a varnish coating mechanism, and an enameled wire manufacturing method according to preferred embodiments of the present invention will be described in order. In this specification, the description of "~" indicating a numerical range includes the upper limit value and the lower limit value of the numerical range.

[0011] [Enameled Wire Manufacturing Apparatus] As shown in FIG. 1, the enameled wire manufacturing apparatus 100 mainly includes an annealing furnace 3, a varnish coating mechanism 4, a baking furnace 5, and a take-up machine 6 along the running direction of the conductor 10, and the varnish coating mechanism 4 has a configuration in which a varnish tank 7 is connected thereto. In the enameled wire manufacturing apparatus 100, while the conductor 10 is run in the lateral direction (horizontal direction) in the annealing furnace 3, the varnish coating mechanism 4, and the baking furnace 5, the conductor 10 is annealed, and then varnish is applied to the conductor 10 and baked (to form an insulating layer) to manufacture enameled wire. Note that, in the enameled wire manufacturing apparatus 100, a wire drawing machine 2 may be installed inline between the supply drum 1 and the annealing furnace 3 to draw the conductor 10 to a certain diameter.

[0012] [Varnish Coating Mechanism] The varnish coating mechanism 4 is a mechanism that is disposed between the annealing furnace 3 and the baking furnace 5 of the enameled wire manufacturing apparatus 100 and applies varnish 12 to the conductor 10 running in the lateral direction. As shown in FIG. 2A, the varnish coating mechanism 4 mainly includes a correction valve 20 and a coating die 30 in order along the running direction of the conductor 10. In the varnish coating mechanism 4, the conductor 10 passes through the correction valve 20 and the coating die 30 in order, and while suppressing vibration with the correction valve 20 and correcting (constraining) the pass line for the conductor 10 running in the lateral direction, the varnish 12 is supplied, and the varnish is uniformly applied with the coating die 30. Note that the conductor 10 here includes a coated conductor after varnish coating.

[0013] The conductor 10 is a so-called wire conductor having conductivity. As the conductor 10, for example, copper, aluminum, etc. are used, and oxygen-free copper, pure copper, copper alloys, etc. are included. The material of the conductor 10 is not particularly limited as long as it has conductivity. The form of the conductor 10 may be a round wire or a flat wire. When the conductor 10 is a round wire, its diameter is, for example, about 0.4 to 1.6 mm. When the conductor 10 is a flat wire, its size (width) is, for example, about 1.5 to 2.0 mm. In either case, the diameter or size (width) of the conductor 10 is not limited. The varnish 12 forms an insulating layer around the conductor 10. As the varnish 12, for example, varnishes containing polyesterimide and polyamideimide, varnishes containing amideimide, varnishes containing esterimide and amideimide, etc. are used.

[0014] The correction valve 20 is a member having a substantially cylindrical shape, and its inner surface has a tapered shape and the diameter decreases from the wire inlet side to the wire outlet side of the conductor 10. The correction valve 20 is housed in the valve holder 22. The valve holder 22 is a member fixed at a certain position in the arrangement of the enameled wire manufacturing apparatus 100, and the position of the correction valve 20 is fixed (regulated) in the state of being housed in the valve holder 22. The position where the correction valve 20 is fixed is preferably a position corresponding to the path line along which the conductor 10 travels. However, since it is difficult to specify the position of the path line of the conductor 10 itself, it is preferable to set it to the position of the designed path line of the enameled wire manufacturing apparatus 100, or to measure the position of the conductor 10 during the operation of the apparatus and set it to the temporal and spatial average position. Supply holes 24 and 26 are respectively formed in the correction valve 20 and the valve holder 22, and the two supply holes 24 and 26 communicate with each other. The varnish tank 7 is connected to the correction valve 20 and the valve holder 22 via the two supply holes 24 and 26. The positions and numbers of the supply holes of the correction valve 20 and the valve holder 22 can be appropriately changed.

[0015] The lateral length of the correction valve 20 is, for example, about 5 to 20 mm. The taper angle θ1 of the correction valve 20 is preferably 4 to 40°. The "taper angle θ1" is an angle formed by the extension line of the inner surface and the central axis of the correction valve when the inner surface of the correction valve 20 is viewed in a longitudinal sectional view parallel to the central axis of the correction valve 20.

[0016] In the varnish application mechanism 4, since the inner surface of the correction valve 20 is tapered, when the varnish 12 is supplied from the varnish tank 7 to the correction valve 20 through the two supply holes 24 and 26, the pressure of the varnish 12 generated by the wedge effect is applied to the conductor 10, and the structure can suppress the vibration of the conductor 10 during running (Fig. 2B). According to such a configuration, when the position of the pass line of the conductor 10 during running deviates from the central axis of the correction valve 20, a restoring force acts to return the position of the pass line of the conductor 10 to the center of the correction valve 20, and the position of the pass line of the conductor 10 is corrected (Fig. 2C). Specifically, in a region where the gap between the conductor 10 and the inner surface of the correction valve 20 is narrow, the static pressure of the varnish 12 is high, and conversely, in a region where the gap between the conductor 10 and the inner surface of the correction valve 20 is wide, the static pressure of the varnish 12 is low, and a restoring force that returns the conductor 10 to the center of the correction valve 20 acts due to the pressure difference.

[0017] In addition, instead of or in combination with the above configuration, the correction valve 20 may adopt other configurations, as long as it can generate pressure with respect to the varnish 12 as a fluid. For example, the correction valve 20 (and its peripheral mechanism) in Fig. 2A may be replaced with the correction valve 20 in Figs. 3A to 3C. In the correction valve 20 of Fig. 3A, a space portion 27 having a larger diameter than these is formed between the inlet portion and the outlet portion of the conductor 10. According to such a configuration, when the varnish 12 is supplied to the correction valve 20, the varnish 12 is temporarily stored or immersed in the space portion 27, and the static pressure of the varnish 12 is applied to the conductor 10. In the structure of Fig. 2B, it is necessary to make the inlet diameter and the outlet diameter smaller than the diameter of the space portion 27. In the correction valve 20 of FIG. 3B, a spiral groove 28 is formed on the inner surface of the correction valve 20. According to such a configuration, when the varnish 12 is supplied to the correction valve 20, the varnish 12 flows spirally along the groove 28, and the dynamic pressure of the varnish 12 is applied from the concave portion of the groove 28 to the conductor 10. In the correction valve 20 of FIG. 3C, two rollers 29 are arranged opposite to each other at the lead-out portion of the conductor 10, and the diameter of the lead-out portion is narrower than the diameter of the lead-in portion. There may be only one roller 29. A lubricating film is formed on the surface of the roller 29. According to such a configuration, when the varnish 12 is supplied to the correction valve 20, the roller 29 with the varnish 12 adhering to its surface touches the conductor 10, and pressure is generated between the roller 29 and the conductor 10 due to the rotation of the roller 29, and the dynamic pressure of the varnish 12 is applied from the roller 29 to the conductor 10. Also with the configurations of FIGS. 3A to 3C, when the position of the pass line of the conductor 10 during running deviates from the central axis of the correction valve 20, a restoring force acts to return the position of the pass line of the conductor 10 to the center of the correction valve 20, and the position of the pass line of the conductor 10 is corrected.

[0018] Returning to FIG. 2A for explanation, the coating die 30 is a so-called die tip, and its inner surface is tapered and the diameter decreases from the lead-in side to the lead-out side of the conductor 10. The tip of the coating die 30 is fitted into the die holder 32. The tip of the coating die 30 is curved, and the inner surface of the die holder 32 is also curved. The die holder 32 is a member fixed at a certain position in the arrangement of the enameled wire manufacturing apparatus 100. The coating die 30 has a slight degree of freedom in the vertical, horizontal, and left-right directions with respect to the running direction of the conductor 10 and can also rotate with respect to the die holder 32 in the state of being fitted into the die holder 32. That is, the coating die 30 is fitted in a floating state with respect to the die holder 32.

[0019] The lateral length of the coating die 30 is about 4 to 20 mm, for example. The taper angle θ2 of the coating die 30 is preferably 4 to 40°. The "taper angle θ2" is an angle formed by the extension line of the inner surface and the central axis of the coating die 30 when the inner surface of the coating die 30 is viewed in a longitudinal cross-sectional view parallel to the central axis of the coating die 30.

[0020] In the varnish coating mechanism 4, since the inner surface of the coating die 30 has a tapered shape, the excess varnish 12 adhering to the conductor 10 is smoothly shaved off during the running of the conductor 10, and the varnish 12 is coated on the conductor 10 with a uniform film thickness.

[0021] In the varnish coating mechanism 4, the correction valve 20 and the coating die 30 are arranged in a state of being laterally separated from each other. It is preferable to arrange the rotation center of the coating die 30 with respect to the pass line of the conductor 10 stabilized by the correction valve 20. For this purpose, it is preferable to arrange the coating die 30 as close as possible to the correction valve 20 within a range that allows the overflow of the varnish 12. In the case of a horizontal type, the axial centers of the nozzles of the correction valve 20 and the coating die 30 generally do not coincide on the same axis. However, by devising the positional relationship between these members and the size of the coating die 30, it is possible to arrange the axes of both nozzles on the same axis or the die surfaces in parallel. The cross-sectional shapes of the conductor passing holes of the correction valve 20 and the coating die 30 are circular or flat rectangular according to the cross-sectional shape of the conductor 10, respectively.

[0022] [Enameled wire manufacturing method] As shown in FIG. 4, in the enameled wire manufacturing method, first, the conductor 10 is annealed in the annealing furnace 3 (S1). Thereafter, the conductor 10 is sent out to the varnish coating mechanism 4, and the varnish 12 is applied to the conductor 10 (S2). Thereafter, the conductor 10 is sent out to the baking furnace 5, and the varnish 12 of the conductor 10 is baked and cured in the baking furnace 5 (S3), and the conductor 10 is wound up by the winding machine 6 (S4). In the method for manufacturing an enameled wire, generally, the varnish application step S2 and the baking step S3 are repeated a plurality of times to form an insulating layer having a desired thickness and manufacture the enameled wire. The number of repetitions of the varnish application step S and the baking step S3 is, for example, about 11 to 23 times, and is not limited.

[0023] In the varnish application step S2, the conductor 10 is passed and run through the correction valve 20 and the coating die 30 in this order. In such a case, in the correction valve 20, while supplying the varnish 12 from the varnish tank 7, the conductor 10 is run, pressure of the varnish 12 is applied to the conductor 10 to suppress vibration of the conductor 10, and the position of the pass line of the conductor 10 is corrected and stabilized. Excess varnish 12 is overflowed from the incoming side of the correction valve 20. When the supply amount of the varnish 12 is Q1, the adhesion amount of the varnish 12 to the conductor 10 is Q2, and the overflow amount of the varnish 12 is Q4, the relational expression Q1 = Q2 + Q4 holds. The overflow amount Q4 of the varnish 12 may be 0 (zero).

[0024] In the coating die 30, the conductor 10 is run in a state where the varnish 12 is adhered to the conductor 10, and while smoothly shaving off the excess varnish 12, the varnish 12 is applied to the conductor 10 with a uniform film thickness. Excess varnish 12 is overflowed from the incoming side of the coating die 30. When the adhesion amount of the varnish 12 to the conductor 10 is Q2, the coating amount of the varnish 12 to the conductor 10 is Q3, and the overflow amount of the varnish 12 is Q5, the relational expressions Q2 = Q3 + Q5 and Q2 > Q3 hold. The overflow amount Q5 of the varnish 12 is not 0 (zero). The correction valve 20 and the coating die 30 are separated from each other as described above, and it is necessary to secure a distance that can allow at least the overflow amount Q5 of the varnish 12 as the separation distance (lower limit), and it is necessary to secure a distance that is not affected or hardly affected by the variation of the catenary curve of the conductor 10 (upper limit).

[0025] According to the above-described embodiment, in the varnish application mechanism 4, the correction valve 20 and the application die 30 are separately installed and arranged in a state of being separated from each other. In such a configuration, (1) as a means for stabilizing the varnish application, instead of aligning the application die 30 with the pass line of the conductor 10, (2) the correction valve 20 is provided with a function of suppressing fluctuations in the pass line of the conductor 10, and by stabilizing the position of the pass line, the positional relationship of the pass line of the conductor 10 between the application die 30 is stabilized. That is, (3) a mechanism is provided that utilizes a mechanism for generating pressure with a fluid (varnish) from the structure of the correction valve 20 to suppress the vibration of the conductor 10 and correct the position of the pass line of the conductor 10. In the application die 30, since it is fitted in a floating state with respect to the die holder 32, the conductor 10 with excess varnish 12 adhering thereto travels through the center of the application die 30, and the varnish 12 can be applied to the conductor 10 with a uniform film thickness, and the structure can suppress the thickness non-uniformity of the insulating layer.

[0026] In this embodiment, incidentally, (A1) fluctuations in the pass line (position of the catenary curve) of the conductor 10 caused by conditions such as temperature, tension, and linear velocity can be minimized, and a stable varnish 12 application environment can be provided. (A2) By correcting the traveling position of the conductor 10 with the correction valve 20, the pass line of the conductor 10 can be constrained without contact and without contacting the conductor 10, so that the conductor 10 and its film are not damaged, and the generation and mixing of foreign substances in the varnish 12 can be suppressed, and the cause of disconnection of the conductor 10 can be reduced. (B) By determining the pass line of the conductor 10 with the correction valve 20, the reproducibility and stability of the positional relationship between the application die 30 installed nearby and the pass line of the conductor 10 can be improved, and thus the time for thickness non-uniformity adjustment can be shortened. (C) The combination of the correction valve 20 and the application die 30 can enhance the ability to attenuate the vibration of the conductor 10 through the fluid film of the varnish 12, and (D) at the same time, the thickness non-uniformity of the insulating layer can be minimized, and a thinner film than before can be realized.

[0027] Note that the varnish coating mechanism is applicable not only to horizontal enameled wire manufacturing equipment but also to the vertical enameled wire manufacturing equipment 200 as shown in Fig. 5. In the vertical enameled wire manufacturing equipment 200, in particular, the varnish coating mechanism 4 and the baking furnace 5 are installed in the vertical direction (vertical direction).

Example

[0028] (1) Preparation of round wire sample A round copper conductor with a diameter of 1.0 mm was prepared as the conductor, and polyamideimide was prepared as the varnish. Using the varnish coating mechanism shown in Fig. 2A, enameled wire of 1AIW conforming to JIS standard 3215 was manufactured. As the correction valve of the varnish supply mechanism, one with a length of about 10 mm and a taper angle θ1 = about 10° was prepared, and as the coating die (die tip), one with a length of about 4.0 mm and a taper angle θ2 = about 8.0° was prepared.

[0029] (2) Preparation of square wire sample A square copper conductor with a width of 2.0 mm × a thickness of 1.0 mm and a corner radius R of 0.4 mm was prepared as the conductor, and enameled wire was manufactured in the same manner as the round wire sample.

[0030] (3) Evaluation of samples In the varnish coating mechanism, the enameled wire when both the correction valve and the coating die were installed was taken as the example, and the enameled wire when the correction valve was intentionally omitted and only the coating die was installed was taken as the comparative example. The thickness non-uniformity ratio of the insulation layer of each sample was calculated and compared. The comparison results of the round wire samples are shown in Table 1, and the comparison results of the square wire samples are shown in Table 2 respectively. The thickness non-uniformity ratio is represented by the maximum film thickness with respect to the minimum film thickness of the insulation layer when the enameled wire is viewed in cross-section, and the closer it is to 1, the more uniformly the insulation layer is formed. Here, in each sample, cross-sections with N = 30 were observed at intervals of 100 mm in the longitudinal direction, the minimum film thickness and the maximum film thickness of the insulation layer were measured, and the thickness non-uniformity ratio was calculated.

[0031]

Table 1

[0032]

Table 2

[0033] As shown in Table 1, in the round wire sample according to the example, the thickness non-uniformity of the insulating layer was reduced compared to the round wire sample according to the comparative example, and the variation in thickness non-uniformity could be improved by about 67%. As shown in Table 2, in the square wire sample according to the example, the thickness non-uniformity of the insulating layer was reduced compared to the square wire sample according to the comparative example, and the variation in thickness non-uniformity could be improved by about 60%.

Industrial Applicability

[0034] The varnish coating mechanism and the enameled wire manufacturing apparatus according to the present invention are useful for manufacturing enameled wires that can suppress, for example, the thickness non-uniformity of the insulating layer.

Explanation of Reference Numerals

[0035] 1 Supply drum 2 Drawing machine 3 Annealing furnace 4 Varnish coating mechanism 5 Baking furnace 6 Take-up machine 7 Varnish tank 10 Conductor 12 Varnish 20 Correction valve 22 Valve holder 24, 26 Supply holes 27 Space part 28 Groove 29 Roller 30 Coating die 32 Die holder 100 Enameled wire manufacturing apparatus (horizontal type) 200 Enameled wire manufacturing apparatus (vertical type)

Claims

1. A varnish coating mechanism for coating varnish while a conductor is running, comprising: a correction valve that receives the supply of the varnish and corrects the position of the path line of the conductor; a coating die that is disposed downstream of the correction valve in the running direction of the varnish while being spaced apart from the correction valve and controls the coating amount of the varnish on the conductor; The varnish coating mechanism is characterized by comprising the above.

2. In the varnish coating mechanism according to Claim 1, when the correction valve receives the supply of the varnish and its interior is filled, if the position of the path line of the conductor deviates from the central axis of the correction valve, the position of the path line of the conductor is corrected to the central axis of the correction valve by the pressure due to the flow of the varnish. The varnish coating mechanism is characterized by this.

3. In the varnish coating mechanism according to Claim 1, the position of the correction valve is fixed, The varnish coating mechanism is characterized in that the inner surface of the correction valve has a tapered shape.

4. In the varnish coating mechanism according to Claim 1, the position of the correction valve is fixed, The varnish coating mechanism is characterized in that a space portion for storing or immersing the varnish is formed in the correction valve.

5. In the varnish coating mechanism according to Claim 1, the position of the correction valve is fixed, The varnish coating mechanism is characterized in that a spiral groove is formed on the inner surface of the correction valve.

6. In the varnish coating mechanism according to Claim 1, the position of the correction valve is fixed, The varnish coating mechanism is characterized in that a roller is disposed with respect to the outgoing line portion of the correction valve.

7. In an enameled wire manufacturing apparatus for coating and baking varnish while a conductor is running, an annealing furnace for annealing the conductor; the varnish coating mechanism according to any one of Claims 1 to 6; a varnish tank for supplying varnish to the varnish coating mechanism; a baking furnace for baking the varnish on the conductor to form an insulating layer; The enameled wire manufacturing apparatus is characterized by comprising the above.

8. In an enameled wire manufacturing method for coating and baking varnish while a conductor is running, a step of annealing the conductor; a step of coating the varnish on the conductor using the varnish coating mechanism according to any one of Claims 1 to 6; a step of baking the varnish on the conductor to form an insulating layer, and comprising the above steps. In the varnish coating step, while supplying varnish to the correction valve, pressure is applied to the conductor to correct the pass line of the conductor, and the amount of varnish applied to the conductor is controlled by the coating die. A method for manufacturing an enameled wire, characterized by this.

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