JP3140817U - Coil parts - Google Patents

Abstract

An object of the present invention is to suppress the possibility of disconnection of a conductive wire connected to a terminal electrode used over time.
A coil component includes a coil around which a conductive wire is wound, and a terminal electrode having a locking portion connected to an end of the conductive wire. The conductive wire includes a core material, a first covering member, and a second covering member. The core material is aluminum, the first covering member is copper coated on the core material, and the second covering member is an insulating polyamide-imide resin coated on the first covering member. Thus, the locking portion of the terminal electrode and the end portion of the conductive wire are diffusion bonded. The terminal electrode 4a has a locking piece 7a that holds and fixes the conductive wire end 12a with the terminal electrode 4a facing each other. The contact length between the terminal electrode locking portion 6a and the outer periphery of the conductive wire end portion 12a is greater than 50% of the outer periphery of the conductive wire end portion 12a.
[Selection] Figure 1

Description

  More specifically, the present invention relates to a coil component in which aluminum (Al) is used as a core material and copper (Cu) is coated around the core material. Furthermore, when the outer peripheral surface of the copper coated with the core material is coated with an insulating resin made of, for example, polyamide-imide resin, and the terminal electrode locking portion and the conductive wire end are diffusion-bonded The present invention relates to a suitable coil component.

  In recent years, weight reduction of automobiles has been regarded as important in order to improve power performance and environmental performance represented by reduction in fuel consumption. Accordingly, the same weight reduction is required for each of the devices and parts mounted on the automobile. In addition, automobiles are being digitized to realize various functions. For this reason, it is necessary to suppress the increase of the vehicle weight accompanying computerization as much as possible.

  Here, ABS (Antilock braking system) is mentioned as an example of the function which an automobile carries. ABS is a system capable of sudden braking without locking tires in order to ensure steering performance such as emergency avoidance. In recent years, automobiles equipped with ABS have become widespread.

  In the ABS, a coil component (also referred to as a solenoid coil device) is used in order to operate a hydraulic valve that pressurizes and depressurizes brake oil. Further, many coil parts (a total of 8 to 12 ABS coils are usually used for one automobile) are often installed in the engine room of the automobile. For this reason, the coil parts must ensure reliability that can sufficiently withstand harsh usage environments such as temperature, humidity, and vibration. At the same time, the requirement to reduce the weight of coil parts must be satisfied.

  Here, a connection example between a wire and a terminal electrode forming a conventional coil component will be described with reference to FIG.

  Patent Document 1 discloses a conventional coil component. This coil component has a coil in which a copper wire is spirally wound, and a terminal electrode for connecting to an end of the copper wire. And after tying and fixing a copper wire to a terminal electrode, the copper wire is connected by immersing a fixed part in a molten solder tank.

  FIG. 6A is an enlarged view of a connection portion between a copper wire and a terminal electrode in the coil component 100 disclosed in Patent Document 1. FIG. For the coil component 100, a method is used in which a copper wire is entangled with a terminal electrode, and then a solder connection is performed by immersing the entangled portion in a molten solder bath. FIG. 6A shows that a copper wire is entangled with the terminal electrode 103 implanted in the drum core 101. The copper wire is covered with an insulating insulating resin film 102. At the time of solder connection, the copper resin and the terminal electrode are electrically and mechanically connected by thermally decomposing the insulating resin film coated around the copper wire with the heat of the molten solder. Then, the solder wire 105 adheres to the whole of the tangled portion of the copper wire and the terminal electrode 103 and the terminal electrode 103 by immersion in the molten solder, and the tangled portion of the copper wire 104 that is the tangled portion with the terminal electrode 103 is formed. It is formed.

  Patent Document 2 discloses a solenoid device. In this solenoid device, a terminal conductor portion of a coil is sandwiched between U-shaped bent portions of a terminal portion, and the terminal conductor portion is joined to the bent portion by fusing.

  FIG. 6B is an enlarged view of the connection portion between the copper wire and the terminal electrode in the solenoid device (coil) 110 disclosed in Patent Document 2. For the solenoid device 110, a method is used in which a copper wire is sandwiched between U-shaped bent portions of a terminal electrode portion, and a terminal conductor portion is joined to the bent portion by fusing (resistance welding). 6B shows that the copper wire is connected to the terminal electrode 113 in the copper wire fusing portion 111. FIG. By the way, this method also welds the copper wire to the terminal electrode 113 while thermally decomposing the coated insulating resin film 114.

Patent Document 3 discloses a coil component in which the main material of the conductive wire is aluminum and the electrical conductivity is increased.
JP 2002-307186 A JP 2002-299118 A Utility Model Registration No.3130031

Conventionally, copper (Cu) has been used as the main material of conductive wires used for coil components (hereinafter, conventional conductive wires are also referred to as copper wires). The biggest reason for using copper for the conductive wire is that copper has good electrical conductivity and can be obtained relatively inexpensively. However, copper has a relatively high density of about 8.90 g / cm ³ . For this reason, when a large number of ABS coils are used in one automobile, the weight of the automobile increases.

  In addition, polyurethane resin is used as an insulating coating for copper wires used in conventional coil components. However, in the case of an ABS coil that is exposed to a high temperature environment in the engine room, it is necessary to take measures against the high temperature in order to ensure reliability.

In the conventional coil component, the conductive wire terminal and the terminal electrode are joined by immersion in molten solder. However, coil parts for automobiles are constantly subjected to vibrations, impacts, etc. that occur when the automobile is running, and soldering may cause problems such as cracks and peeling of solder, resulting in poor reliability. It was.
In addition, the so-called “copper erosion phenomenon” in which the Cu component of the conductive wire elutes in the molten solder is likely to occur, and the conductive wire is thinned and easily breaks.

  Furthermore, as a terminal processing method different from the above, the conductive wire terminal of the coil component and the terminal electrode are joined by resistance welding. In resistance welding, since the connection site is heated in a wide range, it is necessary to increase the voltage applied to the welded portion, and there is a concern about an increase in process time / an increase in cost.

  The present invention has been made in view of the above problems, and its purpose is to enable weight reduction while maintaining excellent electrical conduction, and to prevent problems such as short circuit and disconnection in a high temperature environment. And providing a coil component with excellent reliability.

  The present invention is suitable for a coil component including a coil formed by winding a conductive wire and a terminal electrode having a locking portion connected to an end of the conductive wire. The conductive wire includes a core material, a first covering member, and a second covering member, the core material is aluminum, and the first covering member is copper coated on the core material. The second covering member is a polyamide-imide resin having an insulating property that is covered with the first covering member. And the latching | locking part of a terminal electrode and the edge part of a conductive wire are diffusion-bonded.

  According to the present invention, the weight of the coil component can be reduced by making the core material of the conductive wire aluminum. Also, excellent electrical conduction can be maintained by coating copper around the core material. Also, the terminal electrode locking portion and the conductive wire end are diffusion bonded. For this reason, for example, when this coil component is attached to an automobile, the connection between the terminal electrode locking portion of the terminal coil component and the end of the conductive wire can be reliably maintained even when subjected to vibrations generated during traveling of the automobile. Is possible.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, an example in which the present invention is applied to a coil component 1 (ABS coil) employed in an automobile ABS system will be described. And as a main material of the electroconductive conductive wire which comprises the coil component 1, aluminum is used, It is characterized by the above-mentioned.

First, a configuration example of the coil component 1 will be described with reference to FIG.
FIG. 1A is an external perspective view of the coil component 1. The coil component 1 includes a bobbin 2 molded with resin, a winding coil 5 in which a conductive wire covered with an insulating resin film is spirally wound around the bobbin 2 a predetermined number of times, and both ends of the conductive wire Are constituted by two terminal electrodes 4a and 4b to which are connected. The bobbin 2 has a cylindrical shape, and a through hole 9 having a predetermined radius is formed at the center of the cylinder axis. A hydraulic valve (not shown) is installed in the through hole 9.

  Collar portions 3a and 3b are formed at both ends of the bobbin 2 so that the wound conductive wire does not loosen. The radius of the collar portions 3 a and 3 b is larger than the radius around which the winding coil 5 is wound around the bobbin 2.

  A terminal electrode fixing portion 3d for implanting the terminal electrodes 4a and 4b is formed on the collar portion 3a. The terminal electrode fixing portion 3d is formed by protruding a part of the collar portion 3a. By forming the terminal electrode fixing portion 3d in this manner, the fixing strength of the implanted terminal electrodes 4a and 4b is increased. And the notch part 3c which lacked a part of collar part 3a is formed in the collar part 3a. The notch 3c serves as a guide groove when connecting the conductive wire to the terminal electrodes 4a and 4b, and suitably maintains the arrangement position of the conductive wire.

  Here, the peripheral part of the terminal electrode fixing part 3d is defined as an enlarged area 10, and the enlarged area 10 will be described. On each of the terminal electrodes 4a and 4b, single-blade locking pieces 7a and 7b (see FIG. 1C) for electrically and mechanically fixing the conductive wires are formed. Conductive wire ends 12a and 12b extending along the notch 3c are in contact with the respective terminal electrodes 4a and 4b. The conductive wire ends 12a and 12b are held and fixed by the bent locking pieces 7a and 7b. Thus, let the holding | maintenance part in the state which the latching pieces 7a and 7b fix the conductive wire be the latching | locking parts 6a and 6b.

  Then, the conductive wire and the locking pieces 7a and 7b are processed by diffusion bonding, which will be described later, and formed as a locking portion with improved mechanical / electrical connection reliability. Here, diffusion bonding refers to bonding using the diffusion of atoms generated between the bonding surfaces by pressing the base material in close contact and applying pressure to the extent that plastic deformation does not occur as much as possible under temperature conditions below the melting point of the members to be bonded. It is a method to do. At the time of diffusion bonding, electrodes are applied to the engaging portions 6a and 6b sandwiching the conductive wire end portions 12a and 12b, respectively, and a voltage is applied. The locking portions 6a and 6b are plated with tin or copper. For this reason, when diffusion bonding is performed, the atoms of the respective members in the vicinity of the interfaces between the respective conductive wire end portions 12a and 12b and the locking portions 6a and 6b are diffused and firmly bonded.

FIG. 1B is a perspective view of the coil component 1 with the winding coil 5 removed.
FIG.1 (c) is a perspective view of the coil component 1 in the state which removed the terminal electrodes 4a and 4b from the terminal electrode fixing | fixed part 3d. The terminal electrodes 4a and 4b are formed with fixing portions 8a and 8b for fixing to the terminal electrode fixing portion 3d. Terminal electrode press-fitting holes 10a and 10b for fixing the terminal electrodes 4a and 4b are formed in the terminal electrode fixing portion 3d. The terminal electrode press-fitting holes 10a and 10b are holes that match the cross-sectional shape of the fixing portions 8a and 8b.

  Next, an example of a state in which the locking portion 6a described in FIG. 1 is viewed in cross section along the line A-A ′ will be described with reference to FIG. 2. In addition, since the latching | locking part 6b is comprised similarly, detailed description of the latching | locking part 6b is abbreviate | omitted.

  FIG. 2A is an enlarged view of a state in which the conductive wire end portion 12a is disposed on the locking portion 6a of the terminal electrode 4a and fixedly held. The conductive wire end 12a is held and fixed by the terminal electrode 4a and the locking piece 7a bent 180 °. And the latching | locking part 6a hold | maintained and fixed is connected (joined) by diffusion joining.

  The length of contact between the terminal electrode 4a and the conductive wire end 12a is L1. Similarly, the contact length at which the locking piece 7a and the conductive wire end 12a contact each other is L1 ′. As is clear from FIG. 2A, the conductive wire end portion 12a and the locking portion 6a are arranged such that the contact length (L1 + L1 ′) is larger than 50% of the outer peripheral length of the conductive wire end portion 12a. Is connected.

  FIG. 2B is an enlarged view of a state in which the conductive wire end portion 12a is fixed and held with the curved portion of the locking portion 6a interposed therebetween. In this state, the contact length at which the conductive wire end portion 12a and the locking portion 6a come into contact is L2. At this time, the contact length L2 is larger than 50% of the outer peripheral length of the conductive wire end portion 12a.

  FIG.2 (c) is an enlarged view of the state which crushed the latching | locking part 6a of the state of FIG.2 (b). In this state, the contact length at which the conductive wire end portion 12a and the locking portion 6a come into contact is L3. At this time, the contact length L3 is substantially equal to the outer peripheral length of the conductive wire end portion 12a.

  In the present embodiment, the contact lengths (L1 + L1 ′), L2, and L3 are set to be longer than 50% of the outer peripheral length of the conductive wire end portion 12a. For this reason, the contact area of the conductive wire end portion 12a and the locking portion 6a can be increased, and the contact strength between them can be increased. As a result, even when an external force is applied to the part, it is possible to prevent a problem that the conductive wire end 12a is detached from the terminal electrode 4a. Further, since the contact area between the conductive wire end portion 12a and the locking portion 6a is increased, the contact resistance at the contact portion can be reduced.

  The conductive wire in the present embodiment is characterized in that copper is coated around an aluminum wire whose core material is aluminum, and a polyamide-imide film is formed on the outer periphery of the coated copper.

  The reason why aluminum is used for the core material is to reduce the weight of the coil component 1. The reason why the core material is coated with copper is to increase the tensile strength of the conductive wire itself while obtaining excellent electrical conduction. In addition, the coating of polyamideimide resin was formed on the outer periphery of the coated copper because, compared to conventional urethane resins, this resin has heat resistance that can withstand use in high-temperature environments, and has insulating properties. It is because it is excellent in.

  Here, an example in which a cross section of a conventional wire and a conductive wire in this embodiment is compared will be described with reference to FIG.

FIG. 3A is an example of a cross-sectional view of a general conductive wire conventionally used.
It can be seen that the first covering portion 22 is formed on the outer peripheral surface of the core material 21. The material of the core material 21 is copper. The material of the 1st coating | coated part 22 is resin.
FIG. 3B is an example of a cross-sectional view of the conductive wire in the present embodiment.
The conductive wire of this example includes a core material 15, a first covering portion 16, and a second covering portion 17. It can be seen that the first covering portion 16 is formed on the outer peripheral surface of the core member 15 and the second covering portion 17 is formed on the outer peripheral surface of the first covering portion 16. The material of the core material 15 is aluminum. The material of the first covering portion 16 is copper. The material of the second covering portion 17 is a polyamideimide resin.

Next, an example of the characteristics of each conductive wire will be described with reference to FIG.
FIG. 4A shows an example of characteristics of a conductive wire in which each base material is formed as aluminum, copper, or copper clad aluminum (conductive wire according to the present embodiment).
From this result, the conductive wire according to the present embodiment has a lower specific gravity than the copper wire. For this reason, the conductive wire according to the present embodiment is approximately 60% lighter than a copper wire having the same length.

Further, as a comparison between the core material 15 and the copper coated around the core material 15, for example, when the wire diameter of the conductive wire (excluding the insulating coating) is 1 mm, the diameter of the core material 15 is 0.8 to 0.00 mm. It is desirable to satisfy the relationship of 9 mm and a copper coating thickness of 0.1 to 0.05 mm. The ratio of the diameter of the aluminum core material to the coating thickness of the copper coated on the core material is formed so as to satisfy the relationship of the following formula (1).
Aluminum: Copper = A: B (1)
(0.8 ≦ A ≦ 0.9, 0.05 ≦ B ≦ 0.1, A + 2 × B = 1.0)

Here, as a comparison condition, consider a case where aluminum is smaller than 0.8 mm and copper is larger than 0.05 mm. In this case, the weight of the coil component is increased, and a large amount of copper is used, which increases the cost of the conductive wire.
Moreover, when the aluminum of the conductive wire is larger than 0.9 mm and the copper is smaller than 0.05 mm, the electrical conductivity is lowered and the tensile strength of the conductive wire is lowered. Further, since the amount of copper used is small, the connection strength between the locking portion and the conductive wire end portion is lowered.

  Conventionally used copper, which is the main material of the conductive wire, has a specific gravity of about 8.89. On the other hand, the specific gravity of aluminum, which is the main material of the conductive wire employed in the present invention, is about 2.70, and the specific gravity is about 1/3. Therefore, the weight when the coil component is manufactured can be remarkably reduced, and the weight of the automobile in which the coil component is mounted as an ABS coil can also be reduced. It will be an advantage.

  For example, the inventor of the present invention experimented with a trial production of the coil component 1. The conductive wire according to the present embodiment and the copper wire are wound 515 turns to create five samples each. And the weight of five samples was measured for every conductive wire, and the average weight was calculated | required. As a result, as shown in FIG. 4B, the weight of the coil component using the conductive wire according to the present embodiment is about 5 g, compared with the weight of the coil component using the copper wire (about 11 g). About half. Here, since a total of 8 to 12 ABS coils are generally used in one automobile, reducing the weight of each coil may lead to a significant reduction in the weight of the entire ABS unit. Indicated.

Next, an example of resistance welding and diffusion bonding will be described with reference to FIG.
Both resistance welding and diffusion bonding are techniques for heating and bonding by applying a voltage by pressing a heating electrode at a desired site.
FIG. 5A is an example of resistance welding.
Using the locking piece 7 a, the conductive wire end 33 made of copper as the main material is sandwiched and a current 31 is applied. At this time, the heating part 32 becomes a wide range. In the case of this resistance welding, in order to join the conductive wire whose core material is copper and the locking portion, the temperature of the joining portion must be raised to the melting point of copper (about 1080 ° C.) or more. Further, since the resistance of copper is small, it is necessary to increase the voltage. At this time, since the whole core material is heated and copper is easily melted, the diameter of the conductive wire in the locking portion may be reduced.

FIG. 5B is an example of diffusion bonding.
Diffusion bonding is a technique in which a base material is brought into close contact, and pressure is applied to the extent that plastic deformation does not occur as much as possible under a temperature condition below the melting point of the base material. For this reason, the heating portion 42 is limited to the interface between the conductive wire and the locking portion, and the core material does not melt. For this reason, a conductive wire is not cut | disconnected at the time of joining. As a bonding condition in the diffusion bonding, a range of approximately 750 ° C. or more and a melting point of copper or less is preferable. The reason for this temperature is that the polyimide amide resin insulation film is surely thermally decomposed and the diffusion of atoms at the interface between the copper coating layer of the conductive wire and the terminal electrode is activated to ensure bonding. . In addition, since this bonding temperature is about 200 ° C. lower than the melting point of copper (about 1080 ° C.), the voltage applied at the time of bonding can be lowered and the manufacturing cost / time can be reduced compared to resistance welding. It becomes.

  According to the present embodiment described above, aluminum (Al) is used as the main material of the conductive wire. For this reason, it is possible to ensure the reliability of the coil component that can sufficiently withstand a severe use environment such as temperature, humidity, and vibration.

  By making the core material of the conductive wire aluminum, the weight of the coil component 1 can be reduced. For this reason, even if many coil components 1 are used, the whole weight is light. In addition, by covering copper around the core material, it is possible to increase the tensile strength of the conductive wire while maintaining excellent electrical conduction. Further, the terminal electrode latching portion and the conductive wire end portion are diffusion-bonded at a temperature in the range of approximately 750 ° C. or more and copper melting or less. For this reason, for example, when this coil component is attached to an automobile, the connection between the terminal electrode locking portion of the terminal coil component and the end of the conductive wire can be reliably maintained even when subjected to vibrations generated during traveling of the automobile. Is possible.

  The aluminum conductive wire and the terminal electrode are connected by diffusion bonding. For this reason, the latching | locking part excellent in connection strength is obtained compared with the construction method immersed in the molten solder demonstrated with the conventional coil component 100 (refer Fig.6 (a)).

  Further, in the conventional solenoid device (see FIG. 6B), when the copper wire and the terminal electrode are connected by the joining means, an applied voltage is required so that the temperature is higher than the melting point of copper (about 1080 ° C.). It was. However, the melting point of aluminum, which is the main material of the conductive wire of the coil component 1 according to the present embodiment, is about 660 ° C. For this reason, compared with the case where a copper wire is joined, since it can join at low temperature, an applied voltage can be made low. Therefore, it is possible to simplify the manufacturing process and reduce the cost.

  In addition, although the insulating film made of polyamideimide having excellent heat resistance is used as the insulating film of the conductive wire of the present invention, the temperature condition at the time of diffusion bonding is generally in the range of 750 ° C. or more to the copper melting store or less. Therefore, the film can be removed and the joint connection can be made by applying a single voltage. Furthermore, the fact that the bonding temperature is low can reduce the degree of influence related to the thermal deterioration of the bobbin 2, so that the highly reliable coil component 1 can be obtained.

  Moreover, since each locking piece is integrally formed with the terminal electrode, there is an effect that the manufacturing is easy. Furthermore, the end of the conductive wire is held and fixed in a state in which the locking piece is at least opposed and sandwiches the end of the conductive wire. For this reason, the position shift of the conductive wire in the stage before joining can be suppressed. For this reason, there exists an effect that a joining process is stabilized.

  Further, the contact length where the engaging portion of each terminal electrode comes into contact with the outer periphery of the end portion of the conductive wire is held and fixed in a state where it is larger than 50% of the outer periphery of the end portion of the conductive wire. At this time, since the terminal electrode has a locking piece that is held and fixed across the end portion of the conductive wire in an opposed state, the holding and fixing are facilitated. Further, since the interface for diffusion bonding is widened, there is an effect that the bonding strength is increased.

  Further, since the polyamideimide resin is used as the second covering member 17, the temperature resistance of the coil component 1 is increased, which is suitable when the coil component 1 is used in a high temperature environment. Moreover, since the polyamide-imide resin is a material having excellent insulating characteristics, current leakage does not occur.

  In the above description of the present embodiment, the description has been given of an example in which the present invention is applied to an automobile ABS coil. However, the present invention is not limited to an automobile ABS coil. Needless to say, the coil component according to the present invention can be suitably used in other applications (such as home appliances and industrial electronic devices).

  In addition, the fixing position of the conductive wire is not particularly limited as long as the locking portion and the conductive wire end are in contact with each other at 50% or more of the outer peripheral length of the conductive wire. Furthermore, since a favorable joining state can be ensured, there is an effect that the reliability of the coil component is improved.

  Further, the shape of the holding portion where the locking portion holds the conductive wire end portion may not be a curved shape. The shape of the holding part may be, for example, a linear U-shape. With such a shape, even when the pressure is applied and the locking portion is crushed, the end portion of the conductive wire can be reliably connected to the terminal electrode without disconnection.

  Moreover, in this Embodiment, although the cross-sectional outer periphery of a conductive wire is made into circular shape, since aluminum is a raw material with comparatively low hardness, it can also become elliptical shape. For this reason, if manufacturing conditions are controlled so as not to flatten excessively, the strength does not deteriorate. Furthermore, the cross-sectional shape of the conductive wire is not limited to a circular shape, and may have a square cross section. In this case, since the line area ratio of the winding is improved as compared with the conductive wire having a circular cross section, a coil component having excellent electromagnetic characteristics can be obtained.

It is the block diagram which showed the example of the coil components in one embodiment of this invention. It is the block diagram which showed the example of the latching | locking part in one embodiment of this invention. It is explanatory drawing which showed the example which compares the cross section of the conventional wire and the electrically conductive wire in one embodiment of this invention. It is explanatory drawing which showed the example of the characteristic of each electrically conductive wire. It is explanatory drawing which showed the example of resistance welding and diffusion bonding. It is the block diagram which showed the example of a connection of the conductive wire wound by the conventional coil components.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Coil component, 2 ... Bobbin, 3a, 3b ... Collar part, 3c ... Notch part, 3d ... Terminal electrode fixing part, 4a, 4b ... Terminal electrode, 5 ... Winding coil, 6a, 6b ... Locking part, 7a, 7b ... locking piece, 8a, 8b ... fixed part, 9 ... through hole, 10 ... enlarged region, 12a, 12b ... conductive wire end

Claims (3)

In a coil component including a coil formed by winding a conductive wire and a terminal electrode having a locking portion connected to an end of the conductive wire,
The conductive wire includes a core material, a first covering member, and a second covering member,
The core material is aluminum,
The first covering member is copper coated on the core material,
The second covering member is a polyamide-imide resin having an insulating property that is coated on the first covering member,
The coil part, wherein the terminal electrode locking part and the conductive wire end part are diffusion-bonded. 2. The coil component according to claim 1, wherein the terminal electrode has a locking piece that is held and fixed with an end portion of the conductive wire sandwiched between the terminal electrodes. The contact length between the terminal electrode locking portion and the outer periphery of the end portion of the conductive wire is greater than 50% of the outer periphery of the end portion of the conductive wire. Coil parts as described in.