JP2006031980A - Heat-resistant insulated wire and fusing method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-resistant insulated wire having a heat-resistant insulated film wherein softening, sublimation and peeling of the insulated film by heating can be sufficiently performed in fusing and sufficient conduction and good connection with a terminal can be attained, and to provide a fusing method using it. <P>SOLUTION: In this heat resistant insulated wire, the insulated film comprising a heat-resistant insulating material is formed on the periphery of a conductor wire and the insulated film contains a foaming agent. The fusing method uses it. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat-resistant insulated wire that can be favorably bonded (connected) to a metal terminal (lead) or the like by fusing, and a fusing method using the heat-resistant insulated wire.

  Fusing is widely used as a terminal connection method in which an insulated wire having an insulating film on the outer periphery of a conductor and a terminal are joined by thermal caulking, and is a kind of solid-layer joining. FIG. 3 is a conceptual process diagram showing an example of joining (connection) between a lead and an insulated wire by fusing. First, fusing will be described with reference to FIG.

  As shown in FIG. 3A, first, a hook (U-shaped portion) is formed by the lead 11 of the terminal, and the insulated wire 12 is engaged with the hook. Electrodes 13 a and 13 b are in contact with the lead 11. Next, a voltage is applied between the electrodes 13a and 13b, and the hook portion of the lead 11 is pressed by the electrode 13a.

  Then, a current indicated by an arrow in the drawing flows in the lead 11, and the hook portion of the lead 11 is softened by resistance heat generation. Since the hook portion is simultaneously pressed by the electrode 13a, the hook portion is deformed, and has a shape that encloses the insulated wire 12 as shown in FIG.

  Due to the heat generated in the hook portion, the insulated wire 12 is also heated, and the insulating film 14 is softened and sublimated and peeled off, and the conductor core wire 15 is exposed and is electrically connected to the lead 11 as shown in FIG. Then, a current flows through the core wire 15 and resistance heat is generated, and the core wire 15 and the lead 11 are heated and pressed by this heat generation and the pressing of the electrode 13a, thereby achieving bonding. Such a fusing joint is known as an environmentally friendly joint that does not use solder harmful to the human body.

  In recent years, a heat-resistant insulated wire using a heat-resistant resin such as polyamideimide or polyimide for an insulating film has been used for a coil winding (heat-resistant winding) or the like. When fusing is applied to the connection of the heat-resistant insulated wire, the insulation film of the heat-resistant insulated wire has high heat resistance (softening and sublimation temperature), so that the insulation film is not easily softened by heating and peeled off by sublimation. As a result, the film remains on the electric wires, the core wire of the conductor is not sufficiently exposed, the conduction with the joint portion (crimped portion) of the terminal is insufficient, and the connection with the terminal may not be performed properly.

  Therefore, in order to make the connection by fusing more reliably, the coating coating baking during the production of heat-resistant insulated wires is made by low-temperature baking, and the method of making the film easy to heat soften is partly according to the user's request. Has been done. However, this method has a problem that the heat-resistant temperature of the electric wire is lowered. Moreover, since it is applied only to a part of the electric wires that are subjected to fusing, special seizure management different from other electric wires is required, and there is a problem that the production management of the electric wires is complicated. Therefore, it has been desired to develop a heat-resistant insulated wire that can sufficiently soften, sublimate, and peel off the insulating film by heating without under-baking and can achieve a good connection with the terminal.

  The present invention is a heat-resistant insulated electric wire having a heat-resistant insulating film, and in fusing, the insulating film is sufficiently softened, sublimated, and peeled off by heating to achieve sufficient conduction with the terminal and good connection. An object of the present invention is to provide a heat-resistant insulated wire that can be used.

  As a result of the study, the present inventor has found that the above-mentioned problems can be achieved by adding a foaming agent that foams by heating in fusing to the insulating film, and has completed the present invention.

  The present invention provides a heat-resistant insulated wire formed by forming an insulating film made of a heat-resistant insulating material on the outer periphery of a conductive wire, wherein the insulating film contains a foaming agent. (Claim 1).

  If this heat-resistant insulated wire is connected to a terminal or the like by fusing, the foaming agent decomposes and foams and destroys the film due to heat generated by energization during joining (hereinafter, this characteristic is referred to as fusing property). . As a result, the conductor under the film is exposed and heat conduction is improved, so that softening and sublimation of the film are promoted, and a satisfactory connection with sufficient conduction is achieved.

  As a foaming agent, what has a decomposition temperature of the range of 350 degreeC or more and 450 degrees C or less is preferable. Examples of such a foaming agent include Celtetra BHT-PIPE (trade name, manufactured by Eiwa Kasei Kogyo Co., Ltd., decomposition temperature 350 to 375 ° C.). When the decomposition temperature is less than 350 ° C., foaming is likely to occur when a heat-resistant insulating material containing a foaming agent is painted and baked onto a conductor, and baking (manufacture of an insulated wire) may be difficult.

  On the other hand, when the decomposition temperature exceeds 450 ° C., sufficient foaming does not occur at the time of heating in fusing, and improvement in fusing property may be insufficient. Such foaming agents are difficult to obtain. Claim 2 corresponds to this preferred embodiment, and provides the heat-resistant insulated wire, wherein the foaming agent has a decomposition temperature of 350 ° C. or higher and 450 ° C. or lower. is there.

  The insulating film may be composed of one layer, or may be composed of multiple layers of different materials. When the insulating film is composed of multiple layers, the foaming agent may be contained only in some of the layers. When the foaming agent is contained in only a part of the layers, the fusing property is improved regardless of which layer is contained. However, if the foaming agent is contained in a layer close to the conductor (undercoat layer), the fusing property is improved. This is preferable because the improvement of Claim 4 corresponds to this preferred embodiment, wherein the heat-insulated electric wire is characterized in that the insulating film has two or more layers and the foaming agent is contained in a layer close to the conductor. A heat-resistant insulated wire is provided.

  The heat-resistant insulating material that forms the insulating film is a material that does not soften or sublime even at a temperature of 250 ° C. or higher, and examples thereof include heat-resistant polymers such as polyimide, polyamideimide, and polyesterimide. Claim 3 corresponds to this aspect, and is the heat-resistant insulated wire, wherein the insulating film has a layer made of at least one polymer selected from polyimide, polyamideimide, and polyesterimide. A heat-resistant insulated wire is provided. In an insulated wire using an insulating material that softens or sublimates at less than 250 ° C., the above-mentioned problem in fusing is not so remarkable, and the effect of the present invention is not so remarkable.

  The layer made of at least one polymer selected from polyimide, polyamideimide and polyesterimide is mainly composed of polyimide, polyamideimide or polyesterimide, or a mixture thereof, and consists of a layer made of polyimide and a polyamideimide. Examples thereof include a layer, a layer made of polyesterimide, a layer made of polyimide and polyamideimide, a layer made of polyimide and polyesterimide, and the like, but may contain other components as long as the heat resistance is not impaired.

  The content of the foaming agent in the insulating film varies depending on the type of insulating material and is not particularly limited. However, in the case of a layer composed of at least one polymer selected from polyimide, polyamideimide and polyesterimide, The range of 0.1 to 10% by weight is preferable with respect to the total weight. When the content of the foaming agent is less than 0.1% by weight, foaming at the time of energization heating may be insufficient, and improvement in fusing property may be insufficient. On the other hand, when the content of the foaming agent exceeds 10% by weight, the heat resistance of the electric wire tends to be lowered, and the skin of the film may be roughened during the production of the insulated electric wire, which may impair the appearance of the electric wire.

  Claim 5 corresponds to this preferred embodiment, and in the heat-resistant insulated electric wire according to claim 3, the layer made of at least one polymer selected from polyimide, polyamideimide and polyesterimide contains 0. It provides a heat-resistant insulated electric wire characterized by containing 1 to 10% by weight.

  The preferable range of the thickness of the insulating film is not particularly limited and varies depending on the thickness of the conductive wire, the required insulating properties, and the like. However, in order to more fully achieve the object of the present invention, the thickness of the layer containing the foaming agent is usually preferably in the range of 2 to 80 μm.

  The heat-resistant insulated wire of the present invention can be produced, for example, by applying a heat-resistant resin or a solution of a precursor thereof to a conductive wire serving as a core material, followed by baking and curing the resin. As the baking conditions, the same conditions as in the case of conventional heat-resistant insulated wires (for example, a temperature of 300 ° C. or more) can be adopted. In order to form a layer containing a foaming agent, a resin solution containing a foaming agent is applied. The application of the resin solution can be performed in a plurality of times.

  In order to form a multi-layer insulation coating, first, an undercoat layer is formed by applying and baking a resin solution, then applying and baking a resin solution for forming an upper layer, forming an upper layer, and further if necessary This process is repeated. When polyimide, polyamideimide, polyesterimide or a mixture thereof is used as the heat resistant resin, a varnish of polyimide, polyamideimide, polyesterimide or a mixture thereof is used as the resin solution.

  The heat-resistant insulated wire of the present invention is suitably used for connection with a terminal by fusing. Such a connection is applied to wiring for a wiper, a power window, a starter, a power steering and the like, and is also used as a connection for a commutator of a rotor of a small motor.

  According to a sixth aspect of the present invention, there is provided a fusing method using the above heat-resistant insulated wire. By the fusing method of the present invention, a good connection between the heat-resistant insulated wire and the terminal can be easily obtained.

  When fusing using the heat-resistant insulated wire of the present invention, and according to the fusing method of the present invention, the foaming agent foams due to heat generated by energization, destroys the film, and the conductor under the film is exposed. Softening of the film and sublimation are promoted, and a good connection is formed between the electric wire and the terminal, thereby improving the accuracy of terminal processing. Moreover, in the manufacture of the heat-resistant insulated wire of the present invention, a process under manufacturing conditions different from that of a normal heat-resistant insulated wire, such as under-baking, is not required. Therefore, heat resistance is not impaired, and special management of manufacturing conditions is not required, and a heat-resistant insulated wire with excellent fusing properties can be efficiently manufactured.

  Next, the best mode of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram schematically showing a cross section of an example of a heat resistant insulated wire of the present invention, and FIG. 2 is a schematic diagram schematically showing a cross section of an example of a conventional heat resistant insulated wire.

  FIG. 1A and FIG. 2A are examples in which the insulating films 2 and 7 covering the outer periphery of the conductor core wires 1 and 6 are formed of one layer. The film 7 in FIG. 2A (conventional example) is a resin layer that does not contain a foaming agent and is composed of at least one polymer selected from polyimide, polyamideimide, and polyesterimide, whereas FIG. The film 2 of (Invention Example) is the same in that it is a resin layer composed of at least one polymer selected from polyimide, polyamideimide, and polyesterimide, but the foaming agent 10 is used with respect to the weight of the film 2. It differs in that it contains about 1% by weight.

  FIGS. 1B and 2B show an example in which the insulating films 2 and 7 covering the outer periphery of the conductor core wires 1 and 6 are composed of two layers, that is, the undercoat layers 3 and 8 and the overcoat layers 4 and 9. It is.

  2B (conventional example), neither the undercoat layer 8 nor the overcoat layer 9 contains a foaming agent. Examples of the constitution of the undercoat layer 8 and the overcoat layer 9 include: (1) the undercoat layer 8 is a resin layer made of polyimide and the overcoat layer 9 is a resin layer made of polyamideimide, and (2) the undercoat layer 8 is a polyester. Examples thereof include a resin layer made of imide and a topcoat layer 9 made of polyamideimide or polyimide. Further, as the overcoat layer 9, a self-lubricating layer made of polyamideimide or the like may be provided in place of the above-mentioned polyamideimide or polyimide, or a non-heat-resistant, fusion-bonded layer may be provided in place of the overcoat layer 9. A layer or nylon layer may be provided.

  Here, the self-lubricating layer is a layer provided in the outermost layer of the coating in order to extremely increase the lubricity of the electric wire and make it difficult to cause damage or disconnection in the winding process. What is excellent in heat resistance, flexibility, stability, workability, and appearance, and that can cope with demands for speeding up the coil manufacturing process and improving space efficiency is desired. In addition, the fused layer is provided as the outermost layer of the wire to fuse between the coil wires by methods such as heating at high temperature, heating with electricity, heating in an organic solvent, drying after drying, etc. Layer. By fusing the coil wires, the coil wires are firmly fixed and exhibit excellent (thermal) vibration resistance. Therefore, a fusion layer may be provided on the outermost layer of the electric wire.

  On the other hand, in the film 2 of FIG. 1B (invention example), the overcoat layer 4 does not contain a foaming agent, but the undercoat layer 3 has a foaming agent 10 of 1 with respect to the weight of the undercoat layer 3. Contains about weight percent. Examples of the material of the undercoat layer 3 including the foaming agent 10 include polyimide, polyamideimide, polyesterimide, or a mixture thereof, and the overcoat layer 4 also includes polyimide, polyamideimide, polyesterimide, or a mixture thereof. The materials selected from each can be arbitrarily combined. In addition, a self-lubricating layer made of polyamide imide or the like may be provided as the top coating layer 4 instead of polyimide, polyamide imide, polyester imide, or the like. A wearing layer or a nylon layer may be provided.

  FIG. 1 (c) and FIG. 2 (c) show that the insulating films 2 and 7 covering the outer periphery of the conductor core wires 1 and 6 are three layers, that is, the undercoat layers 3 and 8, the overcoat layers 4 and 9, and the middle This is an example composed of coating layers 5 and 8 '.

  In the film 7 of FIG. 2C (conventional example), neither the undercoat layer 8, the intermediate coat layer 8 ′ nor the overcoat layer 9 contains a foaming agent. Configuration examples of the undercoat layer 8 and the overcoat layer 9 include: (1) a resin layer in which the undercoat layer 8 is made of polyimide, a resin layer in which the intermediate coat layer 8 ′ is made of polyamideimide, and a polyamide imide in which the overcoat layer 9 is made of polyamideimide (2) The undercoat layer 8 is a resin layer made of polyamideimide, the intermediate coat layer 8 'is a resin layer made of polyimide, and the overcoat layer 9 is a self-lubricated layer made of polyamideimide, etc. 3) A resin layer in which the undercoat layer 8 is made of polyesterimide, a resin layer in which the intermediate coat layer 8 'is made of polyimide or polyamideimide, a self-lubricating layer in which the overcoat layer 9 is made of polyamideimide, or the like. Further, instead of the top coat layer 9, a non-heat-resistant fusing layer or a nylon layer may be provided.

  On the other hand, in the film 2 of FIG. 1C (invention example), the overcoat layer 4 and the intermediate coat layer 5 do not contain a foaming agent, but the undercoat layer 3 is formed by adding the foaming agent 10 to the undercoat layer 3. About 1% by weight is included. Examples of the material of the undercoat layer 3 including the foaming agent 10 include polyimide, polyamideimide, polyesterimide, and a mixture thereof. Also, the intermediate coating layer 4 includes polyimide, polyamideimide, polyesterimide, and a mixture thereof. The materials selected from each can be arbitrarily combined. Examples of the overcoat layer 4 include a self-lubricating layer made of polyamideimide or the like. Further, in place of the top coat layer 4, a non-heat-resistant fused layer or nylon layer may be provided.

  The process of fusing using a heat resistant insulated wire as in the example of FIG. 1 is basically the same as conventional fusing. For example, the heat-resistant insulated wire can be satisfactorily connected to a terminal or the like by a process as shown in FIG. That is, by engaging the heat-resistant insulated wire of the present invention with the hook portion of the lead 11 of the terminal, current flows between the electrodes 13a and 13b shown in FIG. 3, and the hook portion is pressed by the electrode 13a. As shown in FIG. 3B, the hook portion is deformed, and the lead wire 15 and the lead 11 are fused, joined, and connected by heat generated by energization.

  In the case of using a conventional heat-resistant insulated wire, the insulation film could not be sufficiently peeled off during heat generation by energization. However, in the case of using the heat-resistant insulated wire of the present invention, the insulation film was peeled off. The core wire 15 from which the insulating film 14 is peeled off as shown in FIG. 3B can be easily formed, and a good connection can be obtained.

Examples 1-3, Comparative Examples 1-3
One of the following resin varnishes on a copper wire having a diameter of 1.0 mm, and 1 weight of foaming agent Cell Tetra BHT-PIPE (trade name, manufactured by Eiwa Kasei Kogyo Co., Ltd., decomposition temperature 350 to 375 ° C.) % Varnish was applied and baked to form an undercoat layer to obtain an electric wire having a cross section as shown in FIG. As a comparative example, an electric wire having a cross section as shown in FIG. 1B was obtained in the same manner except that no foaming agent was added.
[resin]
Polyimide (PI): Pyre-ML Wire Enamels RC-5057 (trade name, manufactured by I.S.T.)
Polyamideimide (PAI): HI-405H-6 (trade name, manufactured by Hitachi Chemical Co., Ltd.)
Polyesterimide (EI): Isomid 40SM-45 (trade name, manufactured by Nichichi Schenectady Chemical Co., Ltd.)

About the obtained electric wire, fusing was performed in the process as shown in FIG. 3, and after connecting the leads, the contact resistance was measured. The fusing was performed by a two-stage energization method. After energization at 1.50 kA for 0.1 seconds, the energization was stopped for 0.1 seconds, and then energized at 2.00 kA for 0.15 seconds. The operation under these conditions was repeated 5 times, and the contact resistance was measured for each. The results are shown in Table 1. In Table 1, the fusing results are displayed according to the following criteria. Moreover, the thing whose appearance was smooth and in which fine foaming was not seen was made the appearance "good".
○: Contact resistance is almost 0Ω
Δ: Contact resistance is 0.1Ω or more ×: Contact resistance is ∞

Examples 4-6, Comparative Examples 4-6
On a copper wire having a diameter of 1.0 mm, the resin varnish of any one of the above-mentioned PI, PAI, and EI, and a foaming agent cell tetra BHT-PIPE (trade name, manufactured by Eiwa Chemical Industry, decomposition temperature 350 to A varnish added with 1% by weight of 375 ° C. was applied and baked to form an undercoat layer. Thereafter, the same PAI varnish as described above or self-lubricating polyamide-imide (SLAI) varnish (blended with low molecular weight polyethylene in PAI varnish) is applied and baked to form an overcoat layer. An electric wire having a cross section as shown in (a) was obtained. As a comparative example, an electric wire having a cross section as shown in FIG. 2B was obtained in the same manner except that no foaming agent was added. The obtained electric wire was subjected to fusing in the same manner as in Examples 1 to 3, and after connecting the leads, the contact resistance was measured. The results are shown in Table 2 based on the same criteria as in Examples 1 to 3.

Examples 7-9, Comparative Examples 7-9
On a copper wire having a diameter of 1.0 mm, the resin varnish of any one of the above-mentioned PI, PAI, and EI, and a foaming agent cell tetra BHT-PIPE (trade name, manufactured by Eiwa Chemical Industry, decomposition temperature 350 to A varnish to which 1% by weight of 375 ° C. was added was applied and baked to form an undercoat layer. Thereafter, the same PI or PAI varnish as described above was applied and baked to form an intermediate coating layer. Further, the same SLAI varnish as described above was applied and baked to form an overcoat layer, thereby obtaining an electric wire having a cross section as shown in FIG. As a comparative example, an electric wire having a cross section as shown in FIG. 3B was obtained in the same manner except that no foaming agent was added. About the obtained electric wire, fusing was performed in a process as shown in FIG. 3, and after connecting the leads, the contact resistance was measured. The results are shown in Table 3 based on the same criteria as in Examples 1 to 3.

  As shown in Tables 1 to 3, in the present invention examples (examples) using a foaming agent, good fusing property is achieved even when any resin is used. On the other hand, in a comparative example using no foaming agent, the fusing property is poor. That is, it is clear from Tables 1 to 3 that excellent fusing properties are achieved by the present invention.

  The heat-resistant insulated wire of the present invention has excellent fusing properties, and by using the fusing method of the present invention using this heat-insulated insulated wire, a good connection between the heat-insulated insulated wire and the terminal can be obtained. It is suitably applied to welding of windings and commutators, welding of windings of transformers and relays, and metal terminals.

It is a schematic diagram which shows typically the cross section of the heat-resistant insulated wire of this invention. It is a schematic diagram which shows typically the cross section of the conventional heat-resistant insulated wire. It is a conceptual process figure which shows the process of an example of fusing.

Explanation of symbols

1, 6, 15 Core wires 2, 7, 14 Insulating film 3, 8 Undercoat layer 5, 8 'Intermediate layer 4, 9 Overcoat layer 10 Foaming agent 11 Lead 12 Insulated wire 13a, 13b Electrode

Claims (6)

  A heat-resistant insulated electric wire formed by forming an insulating film made of a heat-resistant insulating material on the outer periphery of a conducting wire, wherein the insulating film contains a foaming agent.   The heat-resistant insulated wire according to claim 1, wherein the foaming agent has a decomposition temperature of 350 ° C or higher and 450 ° C or lower.   The heat-resistant insulated wire according to claim 1 or 2, wherein the insulating film has a layer made of at least one polymer selected from polyimide, polyamideimide, and polyesterimide.   The heat-resistant insulated wire according to any one of claims 1 to 3, wherein the insulating film has two or more layers, and the foaming agent is contained in a layer close to a conductor.   The heat resistant layer according to claim 3 or 4, wherein the layer made of at least one polymer selected from polyimide, polyamideimide and polyesterimide contains 0.1 to 10% by weight of the foaming agent. Insulated wire. A fusing method using the heat-resistant insulated wire according to any one of claims 1 to 5.

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