JP2012252870A - Apparatus for manufacturing insulated wire and method for manufacturing insulated wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing an insulated wire, which can dry an insulating coating in a short period of time, and impart excellent appearance to the insulated wire, and to provide a method for manufacturing the insulated wire.SOLUTION: The apparatus for manufacturing the insulated wire has a plurality of heating parts 3a, 3b, ...3n for drying each of which is divided into a heating part (a first induction heating coil part) 1a, 1b, ...1n and a heat retaining part (a heating part for heat-retention) 2a, 2b, ...2n respectively. Each of the heating parts 1a, 1b, ...1n and each of the heat retaining parts 2a, 2b, ...2n are structured so that a temperature increase rate of a conducting wire 11 in the heating parts 1a, 1b, ...1n becomes higher than a temperature increase rate of the conducting wire 11 in the heat retaining parts 2a, 2b, ...2n.

Description

  The present invention relates to an insulated wire manufacturing apparatus and an insulated wire manufacturing method, and more particularly to an insulated wire manufacturing apparatus and an insulated wire manufacturing method for forming an insulating layer by applying and baking an insulating paint on a conductor. .

  Conventionally, an enameled wire in which an insulating coating is coated on a conductor is known. Enameled wires are widely used, for example, as wiring for various electric devices and windings for motors and transformers.

  In general enameled wire, the process of applying an insulating varnish on a conductor, and the process of passing the conductor coated with the insulating varnish through a baking furnace, drying and curing the insulating varnish, and baking the insulating layer (insulating film) ) Is repeated several times until a predetermined thickness is reached.

  As a technique related to the enamel wire baking furnace, a hot air circulation type baking apparatus is described in, for example, Japanese Patent Application Laid-Open No. 9-35556 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2003-187658 (Patent Document 2). The hot air circulation type baking apparatus performs enamel wire baking mainly by heat transfer by convection heat. This hot air circulation type printing apparatus has a circulation chamber and a baking chamber for circulating hot air. In this circulation chamber, a heater for air heating, a catalyst for burning the evaporation solvent, a fan for circulating hot air, and the like are arranged. The air heated by the heater is circulated between the circulation chamber and the baking chamber by a fan. Thereby, the insulating varnish applied to the conductor is dried and cured in the baking chamber.

  As a technique relating to the production of enameled wire, a technique for drying enamel varnish using an induction heating means is described in, for example, Japanese Patent Application Laid-Open No. 60-136111 (Patent Document 3). In the manufacture of the enameled wire described in this publication, after enamel varnish is applied to the outside of the conductor, the solvent in the varnish coating layer is evaporated by heating with an induction heating coil, and the varnish coating layer is dried. The applied film is cured with a heater or the like.

  In JP-A-60-136111, by using an induction heating coil, the varnish coating layer can be dried from the inside of the conductor, so compared to a heat source such as hot air that heats the enamel varnish from the outside. It is described that bubbles and cracks can be suppressed from occurring near the surface of the coating film.

JP-A-9-35556 JP 2003-187658 A JP-A-60-136111

  However, the technique described in Japanese Patent Application Laid-Open No. 60-136111 has a problem that it takes time to evaporate the solvent in the varnish coating layer and dry the varnish coating layer when the heating rate in the induction heating coil is small. is there.

  On the other hand, if the heating rate in the induction heating coil is increased in order to quickly evaporate the solvent in the varnish coating layer, it becomes difficult to control the heating temperature below the boiling point of the solvent. If the heating temperature exceeds the boiling point of the solvent before the solvent evaporates sufficiently, there is a problem that when the solvent evaporates, the insulating layer (coating film) foams and the appearance of the insulated wire is impaired.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an insulated wire manufacturing apparatus and an insulated wire manufacturing method capable of drying the insulating paint in a short time and improving the appearance of the insulated wire. Is to provide.

  An insulated wire manufacturing apparatus according to the present invention is an insulated wire manufacturing apparatus for forming an insulating layer by applying an insulating paint to a conductor and baking it, and includes a first induction heating coil section and a heat retaining heating section. I have. The first induction heating coil section is for mainly heating the conductor coated with the insulating paint to a temperature lower than the boiling point of the solvent contained in the insulating paint. The heat-retaining heating section is for mainly heating the conductor heated by the first induction heating coil section to a temperature equal to or higher than the boiling point of the solvent. The insulated wire manufacturing apparatus is configured so that the rate of temperature rise of the conductor by the first induction heating coil unit is greater than the rate of temperature rise of the conductor by the heat retaining heating unit.

  According to the insulated wire manufacturing apparatus of the present invention, the rate of temperature rise of the conductor by the first induction heating coil portion is larger than the rate of temperature rise of the conductor by the heat retaining heating portion. For this reason, first, the conductor can be heated to a temperature lower than the boiling point of the solvent in a short time in the first induction heating coil section, and the heating time can be shortened. Further, since the solvent can be slowly evaporated and evaporated by the heat-retaining heating section, the conductor can be heated to a temperature equal to or higher than the boiling point of the solvent after sufficiently evaporating the solvent. For this reason, foaming of the film (insulating layer) can be suppressed, and the appearance of the insulated wire can be improved.

  Further, the conductor is heated by the induction heating coil using the principle of electromagnetic induction. For this reason, compared with the case where the hot-air circulation type baking apparatus by the contact heat transfer from the outside using hot air is used, since the temperature rising time can be shortened, the length of the furnace can be shortened. Further, since the temperature of the furnace is not required, the cross-sectional area of the furnace can be reduced. Thus, since the length of the furnace can be reduced and the cross-sectional area of the furnace can be reduced, the equipment can be reduced and the structure can be simplified. Further, since the equipment can be made small and the structure can be simplified, the care of foreign matters is facilitated.

  In the above insulated wire manufacturing apparatus, the heat-retaining heating unit is configured to mainly heat the conductor to a temperature lower than the temperature at which the insulating paint is cured. There is further provided a second induction heating coil section for mainly heating the conductor heated by the heat retaining heating section to a temperature higher than the temperature at which the insulating coating is cured. As a result, the conductor can be heated at a temperature increase rate higher than that of the heat-retaining heating part using the second induction heating coil part after the insulating paint is dried, and the time until seizure of the insulating paint can be shortened. it can.

  In the above insulated wire manufacturing apparatus, the heat-retaining heating unit is configured to heat the conductor to a temperature higher than the temperature at which the insulating paint is cured. Thereby, the apparatus configuration can be simplified.

  The method for producing an insulated wire according to the present invention is a method for producing an insulated wire for forming an insulating layer by applying and baking an insulating paint on a conductor, and includes the following steps.

  The conductor coated with the insulating paint is heated by the first induction heating coil section to a temperature lower than the boiling point of the solvent contained in the insulating paint. The conductor heated by the first induction heating coil section is heated by the heat retaining heating section above the boiling point of the solvent. The rate of temperature rise of the conductor by the first induction heating coil portion is higher than the rate of temperature rise of the conductor by the heat retaining heating portion.

  According to the method for manufacturing an insulated wire of the present invention, the rate of temperature rise of the conductor by the first induction heating coil portion is higher than the rate of temperature rise of the conductor by the heating portion for heat retention. For this reason, like the above, while being able to shorten a heating time, foaming of a membrane | film | coat (insulating layer) can be suppressed and it becomes possible to make the external appearance of an insulated wire favorable.

  Further, similarly to the above, the length of the furnace can be shortened because the temperature raising time can be shortened as compared with the case where the hot air circulation type baking apparatus is used. Further, since the temperature of the furnace is not required, the cross-sectional area of the furnace can be reduced. Thus, since the length of the furnace can be reduced and the cross-sectional area of the furnace can be reduced, the equipment can be reduced and the structure can be simplified. Further, since the equipment can be made small and the structure can be simplified, the care of foreign matters is facilitated.

  In the above method for manufacturing an insulated wire, the heat-retaining heating unit heats the conductor to a temperature lower than the temperature at which the insulating paint is cured. There is further provided a step of heating the conductor heated by the heat-retaining heating unit by the second induction heating coil unit at a temperature equal to or higher than a temperature at which the insulating paint is cured. Thereby, like the above, the conductor can be heated at a temperature rising rate larger than that of the heat-retaining heating part by using the second induction heating coil part after the insulating paint is dried, and the time until the insulation paint is seized can be reduced. It can be shortened.

  In the method for manufacturing an insulated wire, the heat-retaining heating unit heats the conductor to a temperature equal to or higher than the temperature at which the insulating paint is cured. Thereby, the apparatus configuration can be simplified.

  As described above, according to the present invention, it is possible to obtain an insulated wire manufacturing apparatus and an insulated wire manufacturing method capable of drying the insulating paint in a short time and improving the appearance of the insulated wire.

It is a schematic diagram which shows roughly the structure of the manufacturing apparatus of the insulated wire in one embodiment of this invention. It is a figure which shows the temperature control at the time of drying in the manufacturing apparatus of the insulated wire of FIG. It is a figure which shows the temperature control at the time of hardening in the manufacturing apparatus of the insulated wire of FIG. It is a schematic diagram which shows roughly the structure which uses the induction heating coil for heat insulation of the manufacturing apparatus of the insulated wire shown in FIG. 1 also as a heating apparatus for hardening of an insulating paint. The schematic diagram (A) which shows schematically the structure of the manufacturing apparatus of the insulated wire in the modification of this invention, and the figure (B) which shows the structure of the heating apparatus for drying seen from the arrow VB direction of the schematic diagram (A) It is. It is a figure which shows the relationship between time and the temperature of a conductor. It is a schematic sectional drawing (C) which follows the XIIc-XIIc line | wire of the side view (A), front view (B), and front view (B) for demonstrating the structure of a cocoon-type coil.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Referring to FIG. 1, an insulated wire manufacturing apparatus 10 </ b> A according to the present embodiment is for forming an insulating layer by applying and baking an insulating paint on a conductive wire (conductor) 11, which includes a plurality of coating tanks ( Application unit) 6, a plurality of dice devices 7, drying heating devices 3 a, 3 b,..., 3 n, a curing heating device 4, and a plurality of glass tubes 5.

  Each of the plurality of coating tanks 6 is filled with an insulating paint such as a polyamide imide resin varnish or a polyimide resin varnish, and the conductor 11 passes through the coating tank 6 so that the outer peripheral surface of the conductor 11 is covered with the insulating paint. It is comprised so that can be apply | coated. Each of the plurality of dice devices 7 is configured such that the thickness of the insulating coating applied to the outer peripheral surface of the conductor 11 can be controlled to a constant thickness as the conductor 11 passes through the dice device 7.

  The drying heating devices 3a, 3b,..., 3n are for heating the conductor 11 and the insulating paint in order to dry the insulating paint applied on the conductor 11. Here, the drying of the insulating paint means heating to a temperature at which the solvent contained in the insulating paint is vaporized and the insulating paint is not cured. The drying heating devices 3a, 3b,..., 3n are arranged in order along the moving path of the conductor 11 (the traveling path indicated by the conductor 11 and the one-dot chain line in FIG. 1). The heating unit 3a, the second drying heating unit 3b,..., And the nth drying heating unit 3n have a plurality of drying heating units. Although there is no restriction | limiting in particular in the number of the heating parts for drying, Preferably it is about ten pieces. Each of the plurality of drying heating units 3a, 3b, ..., 3n is an induction heating coil.

  Each of the plurality of drying heating sections 3a, 3b, ..., 3n includes heating sections (first induction heating coil sections) 1a, 1b, ..., 1n, and a heat retaining section (heat retaining heating section) 2a. 2b,..., 2n. The heating units 1a, 1b, ..., 1n and the heat retaining units 2a, 2b, ..., 2n are configured such that both temperatures are controlled separately. In particular, the heating units 1a, 1b,..., 1n so that the heating rate in the heating units 1a, 1b,. And each of the heat retaining units 2a, 2b,..., 2n is configured. Specifically, the heating units 1a, 1b,..., 1n induction heating coils and the heat retaining units 2a, 2b,..., 2n induction heating coils have the number of turns, wire diameter, coil length, etc. It is configured to be different as appropriate. For example, the heating units 1a, 1b,..., 1n induction heating coils and the heat retaining units 2a, 2b,..., 2n induction heating coils differ only in length (for example, heating units 1a, 1b,. 1n is shorter than the heat retaining portions 2a, 2b,..., 2n), and the temperature rising speed of both is adjusted by the current flowing through both.

  The curing heating device 4 is for heating the conductor 11 and the insulating paint in order to cure the insulating paint dried after being applied on the conductor 11. Here, curing the insulating paint means heating to a temperature higher than the temperature at which the insulating paint is cured. The curing heating device 4 is preferably an induction heating coil (second induction heating coil portion), but may be heated by a heat source such as hot air, infrared rays, or electric heat. In the above description, the case where the heat retaining units 2a, 2b,..., 2n are made of induction heating coils has been described, but the heat retaining units 2a, 2b,..., 2n are also heated by a heat source such as hot air, infrared rays, and electric heat. It may be a thing.

  Each of the plurality of glass tubes 5 is disposed so as to surround the outer periphery of the conductor 11 inside each of the plurality of drying heating units 3a, 3b, ..., 3n. The glass tube 5 is provided for liquefying and recovering the solvent that is vaporized when the insulating coating applied on the conductor 11 is dried. That is, the glass tube 5 is configured such that the solvent evaporated when the insulating paint is dried is condensed on the surface of the glass tube 5 and adhered as droplets, and dropped into a separate collection container to recover the solvent. Has been.

  Each of the plurality of coating tanks 6 and each of the plurality of drying heating units 3a, 3b,..., 3n are alternately arranged along the movement path of the conductor 11. Here, the coating tank 6 and the drying heating unit which form a pair are such that the coating tank 6 is located on the upstream side and the drying heating unit is located on the downstream side in the movement path of the conductor 11. A dice device 7 is disposed between the coating tank 6 and the drying heating unit. The curing heating device 4 is disposed only on the downstream side of the drying heating unit 3n disposed on the most downstream side of the plurality of drying heating units 3a, 3b, ..., 3n.

  In the above description, the induction heating coil unit of the heating unit and the induction heating coil unit of the heat retaining unit are separately provided. However, the induction heating coil unit of the heating unit and the induction heating coil unit of the heat retaining unit are described. It may be integrated. When these are integrated, the induction heating coil unit and the heat retaining unit of the heating unit are set so that the temperature rising rate of the induction heating coil unit of the heating unit is larger than the temperature rising rate of the induction heating coil unit of the heat retaining unit. The number of turns, the wire diameter, the coil length, etc. are different from those of the induction heating coil section.

  In the above description, the case where there are a plurality of coating tanks 6 has been described, but a configuration in which a plurality of conductors pass through one coating tank 6 may be employed. In this case, one coating tank 6 has a plurality of coating portions, and one coating portion corresponds to a passage portion of one conductor.

  As the insulating paint, for example, an enamel-coated constituent resin dissolved in a solvent is used. This constituent resin is not particularly limited as long as it has high insulating properties and high heat resistance. Specifically, a polyamide resin, a polyimide resin, a polyamideimide resin, a polyesterimide resin, or the like can be suitably used. As the solvent, N-methyl-2-pyrrolidone or cresol can be used.

  Specific examples of the conductor 11 include, for example, a copper wire, a copper alloy wire, a tin-plated copper wire, an aluminum wire, an aluminum alloy wire, a steel core aluminum wire, a copper fly wire, a nickel-plated copper wire, a silver-plated copper wire, and a copper covering. An aluminum wire etc. are mentioned. The conductor 11 may be a round wire or a flat wire.

Next, the manufacturing method of the insulated wire of this Embodiment is demonstrated.
Referring to FIG. 1, first, the conductor 11 passes through the coating tank 6 positioned at the uppermost stream in the movement path of the conductor 11, so that the first layer of insulating paint is applied to the outer peripheral surface thereof. Thereafter, the conductor 11 coated with the first layer of the insulating paint passes through the dice device 7 so that the thickness of the first layer of the insulating paint is controlled to be constant. Thereafter, the conductor 11 and the insulating paint are heated by the drying heating unit 3a. This heating is performed at a temperature at which the solvent in the first-layer insulating paint is vaporized and the first-layer insulating paint is not cured. At this time, as shown in FIG. 3, the temperature rising rate in the heating unit 1a is controlled to be larger than the temperature rising rate in the heat retaining unit 2a. The heating unit 1a heats to a temperature lower than the boiling point of the solvent contained in the insulating paint, and the heat retaining unit 2a slowly heats from a temperature lower than the boiling point of the solvent to a temperature slightly exceeding the boiling point. As a result, the solvent in the first-layer insulating coating is vaporized, and the first-layer insulating coating is dried.

  Thereafter, the conductor 11 coated with the first-layer insulating paint passes through the second coating tank 6 to apply the second-layer insulating paint onto the first-layer insulating paint. Is done. Thereafter, the conductor 11 coated with the second-layer insulating paint passes through the dice device 7 so that the thickness of the second-layer insulating paint is controlled to be constant. Thereafter, the conductor 11 and the insulating paint are heated by the drying heating unit 3b. This heating is performed at a temperature at which the solvent in the second-layer insulating coating is vaporized and the second-layer insulating coating is not cured. At this time, as shown in FIG. 3, the temperature rising rate in the heating unit 1b is controlled to be larger than the temperature rising rate in the heat retaining unit 2b. The heating unit 1b heats to a temperature lower than the boiling point of the solvent contained in the insulating coating, and the heat retaining unit 2b slowly heats from a temperature lower than the boiling point of the solvent to a temperature slightly exceeding the boiling point. As a result, the solvent in the second layer insulating paint is vaporized and the second layer insulating paint is dried.

  The above application and drying are repeated a predetermined number of times (n times: for example, 10 times), and n layers of insulating paint are laminated on the outer peripheral surface of the conductor 11.

  Thereafter, the conductor 11 is heated by the curing heating device 4. This heating is performed at a temperature equal to or higher than the temperature at which the insulating coatings from the first layer to the n-th layer are cured. At this time, as shown in FIG. 3, the heating temperature in the curing heating device 4 is higher than the heating temperatures (for example, the reached temperature is 230 ° C.) of the drying heating units 3 a, 3 b,. For example, the ultimate temperature is controlled to be 270 ° C. As a result, the first to nth insulating coatings are cured on the conductor 11. Thereafter, the insulated wire of the present embodiment is manufactured through cooling, winding around a bobbin, and the like.

Next, the effect of this Embodiment is demonstrated.
According to the present embodiment, as shown in FIG. 2, the heating rate by the heating units 1a, 1b,..., 1n is larger than the heating rate by the heat retaining units 2a, 2b,. . For this reason, it can heat to the temperature below the boiling point of a solvent for a short time with heating part 1a, 1b, ..., 1n first, and can shorten heating time. Further, since the solvent can be slowly evaporated and evaporated by the heat retaining portions 2a, 2b,..., 2n, the solvent can be sufficiently evaporated and then heated to a temperature equal to or higher than the boiling point of the solvent. For this reason, foaming of an insulating layer can be suppressed and it becomes possible to make the external appearance of an insulated wire favorable.

  Further, according to the present embodiment, the heat retaining portions 2a, 2b,..., 2n heat the conductor 11 to below the temperature at which the insulating paint is cured, and the curing heating device 4 cures the conductor 11 with the insulating paint. Heat above temperature. For this reason, after drying the insulating paint, it can be heated at a temperature rising rate larger than the heat retaining parts 2a, 2b,..., 2n using the heating device 4 for curing, and the time until seizure of the insulating paint is shortened. can do.

  In addition, since each of the heating units 1a, 1b, ..., 1n, the heat retaining units 2a, 2b, ..., 2n, and the curing heating device 4 are induction heating coils, the principle of electromagnetic induction is used. The conductor can be heated. For this reason, compared with the case where the hot-air circulation type baking apparatus by the contact heat transfer from the outside using hot air is used, since the temperature rising time can be shortened, the length of the furnace can be shortened. Further, since the temperature of the furnace is not required, the cross-sectional area of the furnace can be reduced. Thus, since the length of the furnace can be reduced and the cross-sectional area of the furnace can be reduced, the equipment can be reduced and the structure can be simplified. Further, since the equipment can be made small and the structure can be simplified, the care of foreign matters is facilitated.

  Next, a modified example of the insulated wire manufacturing apparatus of the present embodiment will be described with reference to FIGS.

  In FIG. 1, the case where the heating device 4 for curing is provided separately from the induction heating coils 2 a, 2 b,..., 2 n has been described, but as shown in FIG. ... each of 2n may be configured to heat the conductor 11 above the temperature at which the insulating paint is cured. In this case, the insulating paint is baked (dried and cured) for each application of the insulating paint, and it is not necessary to provide the curing heating device 4 separately. For this reason, an apparatus structure can be simplified.

  In FIG. 1, the heating units 1 a, 1 b,..., 1 n are composed of a plurality of induction heating coils, and the heat retaining units 2 a, 2 b,. As shown in FIGS. 5A and 5B, the heating units 1a, 1b,..., 1n are composed of, for example, one induction heating coil 1, and the heat retaining units 2a, 2b,. 2n may also be composed of one induction heating coil 2. In this case, each of the induction heating coils 1 and 2 needs to be configured so that a plurality of conductors 11 can be simultaneously disposed therein. The induction heating coil 1 has a plurality of heating portions 1a, 1b,..., 1n corresponding to the portions for heating the conductors 11, and the induction heating coil 2 is a plurality of portions corresponding to the portions for heating the conductors 11. , 2n.

  Each of the induction heating coils 1 and 2 has a rectangular outer shape as seen from the direction along the traveling direction of the conductor 11 (the direction of the arrow VB in FIG. 5A) as shown in FIG. Preferably it is. That is, it is preferable to have a rectangular outer shape in which the dimension L in the direction in which the plurality of conductors 11 are arranged is large and the dimension W in the direction orthogonal to the direction is small. If a plurality of conductors 11 can be arranged simultaneously, the outer shape of the induction heating coil 3 viewed from the traveling direction of the conductors 11 is not limited to a rectangle, but a trapezoid, a parallelogram, a rhombus, a polygon, a perfect circle, an ellipse, Any shape such as a track shape may be used.

  In the insulated wire manufacturing apparatus 10B shown in FIGS. 5A and 5B, each of the heating section and the heat retaining section is formed of one induction heating coil, so the number of parts of the manufacturing apparatus can be reduced. The configuration can be simplified.

  5 (A) and 5 (B), the illustration of the curing heating device is omitted for convenience of explanation, but these devices 10B also have the heat retaining portions 2a, 2b, ... the heating device 4 for curing disposed only on the downstream side of the heat retaining portion 2n disposed on the most downstream side of 2n. 5 (A) and 5 (B), the heat-retaining devices 4a, 2b,. You may be comprised so that it may heat more than the temperature to do.

  1, 4, and 5 (A) and 5 (B), induction heating coils 1, 2, 1 a, 1 b,..., 1 n, 2 a, 2 b,. Although the coil has been described, a so-called so-called coil may be used. As shown in FIGS. 7A, 7 </ b> B, and 7 </ b> C, the soot-coiled coil includes two extending portions 20 a that extend linearly along the conductor 11 while sandwiching the conductor 11, and 2 It consists of the one conducting wire 20 which has the bending part 20b connected to each edge part of the one extension part 20a. The bent portion 20 b is bent so as to go around the conductor 11 so as not to interfere with the conductor 11.

  In addition, in FIG. 1, FIG. 4, and FIGS. 5A and 5B, the induction heating coils 1, 2, 1a, 1b,..., 1n, 2a, 2b,. , Other types of coils other than 竪 竪 type may be used.

  1 and 4, the configuration using the glass tube 5 has been described. However, the glass tube 5 is not provided, and an enclosure is formed so as to surround the entire insulated wire manufacturing apparatus 10 </ b> A. Alternatively, a configuration may be employed in which solvent vapor is sucked from the outside and dew condensation is performed outside.

Next, the study conducted by the inventor will be described.
An insulating enamel varnish made of polyamideimide resin was applied to a conductor made of copper having a wire diameter of φ0.9 mm, and then heat history heating shown in P1 of FIG. 6 was performed. This heating (P1) is performed by heating to a temperature at which the boiling point of the solvent contained in the insulating enamel varnish is exceeded and the insulating enamel varnish is cured. As a result, the insulating enamel varnish dries and hardens. The application and heating (drying and curing) of this insulating enamel varnish were repeated 6 times. The insulated wire thus obtained is shown in Table 1 below as a sample (1).

  An insulating enamel varnish made of polyamide-imide resin was applied to a conductor made of copper having a wire diameter of φ0.9 mm, and then the heat history shown in P2 of FIG. 6 was applied. The temperature increase rate at P2 was set larger than the temperature increase rate at P1. This heating (P2) is performed by heating to a temperature at which the boiling point of the solvent contained in the insulating enamel varnish is exceeded and the insulating enamel varnish is cured. As a result, the insulating enamel varnish dries and hardens. The insulating enamel varnish was applied and heated (dried and cured) once. The insulated wire thus obtained is shown in Table 1 below as a sample (2).

  In addition, after applying an insulating enamel varnish made of polyamide-imide resin to a conductor made of copper having a wire diameter of φ0.9 mm, heat history heating shown in P3 of FIG. 6 was performed. This heating (P3) is relatively small from the boiling point to the temperature at which the insulating enamel varnish is cured after being heated to the boiling point of the solvent contained in the insulating enamel varnish at a relatively high heating rate (about 400 ° C./second). It is performed by heating at a temperature rising rate (about 40 ° C./second). As a result, the insulating enamel varnish dries and hardens. The application and heating (drying and curing) of this insulating enamel varnish were repeated 6 times. The insulated wire thus obtained is shown in Table 1 below as a sample (3).

  About each insulated wire of samples (1) to (3) obtained above, appearance, film thickness, glass transition temperature Tg, pinhole, flexibility, adhesion, thermal shock resistance, energy required for heating , And the maximum time to manufacture of the insulated wire. The results are also shown in Table 1 below.

  For pinholes, item 6 of “Enamelled wire test method” of JIS C 3003 in the previous JIS standard list. Uniformity, c) Evaluation was made by the method described in the pinhole method. Specifically, the length of the test piece was 6 m, a length of 5 m or more was immersed in the liquid, a voltage was applied, and the number of generated pinholes was examined.

  Regarding flexibility, item 7 of “Enamel wire test method” of JIS C 3003 in the old JIS standard list. The flexibility was evaluated by the method described in the 7.1A method. Specifically, a test piece (electric wire) was wound 10 times around a round bar having a self-diameter (same diameter as the electric wire to be evaluated: 1d), and the presence or absence of a crack in the insulating film was evaluated.

  As for adhesion, item 8 of “Enamel wire test method” of JIS C 3003 in the old JIS standard list. Evaluation was made by the method described in Adhesion.

  Furthermore, for thermal shock resistance, after the wire was stretched by 20% (after stretching to 120% of the original length), the wire was wrapped around a round bar with a diameter twice as long as its own diameter, and the temperature was 240 ° C. And left for 1 hour, and then the presence or absence of cracks was evaluated.

  From the results shown in Table 1, in sample (1), a good enamel wire was obtained in appearance and characteristics, but it took too much time for each heating. In sample (2), the heating time for each time was short, but before the solvent sufficiently evaporated (vaporized), the solvent reached the boiling point, so that the insulating coating foamed and the appearance was impaired.

  On the other hand, sample (1) can be baked in a short time, has a good appearance without foaming in the insulating paint, and has good characteristics (film thickness, glass transition temperature Tg, pinhole, possible An enameled wire having flexibility, adhesion, and thermal shock resistance was obtained.

  The embodiments and examples disclosed above are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments and examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims. .

  INDUSTRIAL APPLICABILITY The insulated wire manufacturing apparatus and the insulated wire manufacturing method of the present invention can be used for manufacturing insulated wires suitable for windings such as motors and transformers and various wirings of other electrical devices.

  1, 2 induction heating coils, 1a, 1b, ..., 1n heating section, 2a, 2b, ..., 2n heat retaining section, 3a, 3b, ..., 3n drying heating section, 4 curing heating device 5 Glass tube, 6 coating tank, 7 dice device, 10A, 10B insulated wire manufacturing device, 11 conductor.

Claims (6)

An insulated wire manufacturing apparatus for forming an insulating layer by applying an insulating paint to a conductor and baking it,
A first induction heating coil portion for heating the conductor coated with the insulating paint to a temperature below the boiling point of the solvent contained in the insulating paint;
A heat-retaining heating part for heating the conductor heated by the first induction heating coil part to a temperature not lower than the boiling point of the solvent;
The insulated wire manufacturing apparatus configured such that a rate of temperature rise of the conductor by the first induction heating coil unit is greater than a rate of temperature rise of the conductor by the heat-retaining heating unit. The heat-retaining heating unit is configured to heat the conductor to a temperature lower than a temperature at which the insulating paint is cured,
The insulated wire manufacturing apparatus according to claim 1, further comprising a second induction heating coil unit for heating the conductor heated by the heat retaining heating unit to a temperature equal to or higher than a temperature at which the insulating paint is cured.   The insulated wire manufacturing apparatus according to claim 1, wherein the heat retaining heating unit is configured to heat the conductor to a temperature equal to or higher than a temperature at which the insulating paint is cured. A method for producing an insulated wire for applying an insulating paint to a conductor and baking it to form an insulating layer,
Heating the conductor coated with the insulating paint by a first induction heating coil unit to a temperature lower than the boiling point of the solvent contained in the insulating paint;
A step of heating the conductor heated by the first induction heating coil part to a temperature equal to or higher than the boiling point of the solvent by a heat-retaining heating part,
The method for manufacturing an insulated wire, wherein a temperature rise rate of the conductor by the first induction heating coil portion is higher than a temperature rise rate of the conductor by the heat retaining heating portion. The heat-retaining heating unit heats the conductor to a temperature lower than the temperature at which the insulating paint is cured,
The method for manufacturing an insulated wire according to claim 4, further comprising a step of heating the conductor heated by the heat-retaining heating unit with a second induction heating coil unit at a temperature higher than a temperature at which the insulating paint is cured. .   The method for manufacturing an insulated wire according to claim 4, wherein the heat retaining heating unit heats the conductor to a temperature at which the insulating paint is cured.

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