Coil unit and induction heating device or non-contact power supply device using the same

Abstract

To provide a coil unit and an induction heating device or a non-contact power supply device using the same which suppress the electrolytic corrosion of aluminum over time at connections between a plurality of coil wires and connection terminals and the increase in contact resistance at the connections due to thermal history (creep phenomenon).SOLUTION: A coil unit and an induction heating device or a non-contact power supply device using the same includes: a coil wire 10 primarily composed of aluminum and covered with an insulating coating; a child stranded wire bundle 2 formed by twisting a plurality of coil wires; a connection terminal 20 primarily composed of a copper-based metal material having a crimped portion 21 for joining the child stranded wire bundle; and a connection portion 3 formed by partially removing the insulating coating from the portion of the coil wire that comes into contact with the connection terminal and joining it to the crimped portion, thereby electrically connecting the child stranded wire bundle and the connection terminal. The connection portion is configured such that the entire connection portion is covered with solder.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a coil unit and an induction heating device or a contactless power supply device using the same. [Background technology]

[0002] Patent Document 1 discloses an electromagnetic induction heating device that aims to suppress deterioration over time due to oxidation in the connection terminals of a coil. This electromagnetic induction heating device is configured to store and melt solder or brazing filler metal in a storage compartment provided in the connection terminal of a conductor whose main component is aluminum, while eliminating the insulating properties of the insulating coating around the conductor to establish an electrical connection.

[0003] Patent Document 2 discloses a heating coil for induction heating that aims to improve reliability and connection stability at the connection between a coil conductor using aluminum wire and a connection terminal. The connection between this coil conductor using aluminum wire and a connection terminal includes a coil conductor made by twisting together multiple strands of aluminum wire with an insulating coating on the outer layer, and connection terminals for receiving a supply of power on both ends of the coil conductor, and the connection terminals include storage sections in which the strands of the coil conductor are formed into a flat shape in three stages and fixed under pressure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-120683 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-157546 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a coil unit that suppresses the electrolytic corrosion of aluminum over time at the connection points between multiple coil wires and connection terminals and the increase in contact resistance at the connection points due to thermal history (creep phenomenon), and an induction heating device or a contactless power supply device using the same. [Means for solving the problem]

[0006] The coil unit and the induction heating device or contactless power supply device using the coil unit according to the present disclosure include a coil wire primarily composed of aluminum covered with an insulating coating, a child stranded wire bundle formed by twisting multiple coil wires, a connection terminal primarily composed of a copper-based metal material having a crimped portion for joining the child stranded wire bundle, and a connection portion electrically connecting the child stranded wire bundle and the connection terminal by partially removing the insulating coating from a portion of the coil wire that comes into contact with the connection terminal and joining the crimped portion, and the connection portion is configured so that the entire connection portion is covered with solder. [Effects of the Invention]

[0007] The coil unit and the induction heating device or contactless power supply device using the coil unit according to the present disclosure can isolate and seal the connection portion where the child stranded wire bundle of the coil unit and the connection terminal are electrically connected from the outside. Therefore, the connection portion does not come into contact with an electrolytic medium such as water, and even if the connection terminal is made of a dissimilar metal and the coil wire is primarily made of aluminum, and there is a potential difference of 0.65 V or more, the galvanic corrosion of the aluminum at the connection portion over time can be suppressed. Furthermore, the connection portion can be firmly and integrally joined by mechanical joining. Therefore, the contact resistance at the connection portion can be reduced to nearly zero, and an increase in contact resistance at the connection portion due to thermal history (creep phenomenon) can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view of a coil unit according to a first embodiment; [Figure 2] 1 is a cross-sectional view of a child stranded wire bundle of a coil unit according to the first embodiment. [Figure 3] 1 is a cross-sectional view of a coil unit according to the first embodiment; [Figure 4] FIG. 1 is a diagram showing an electrochemical potential table according to the first embodiment. [Figure 5] 1 is an enlarged plan view of a terminal portion of a coil unit according to the first embodiment; [Figure 6] Schematic diagram of ultrasonic soldering of a coil unit in embodiment 1 [Figure 7] 1 is an enlarged plan view of a terminal portion of a coil unit according to a first embodiment and a cross-sectional view of a connection portion; [Figure 8] 1 is an enlarged plan view of a terminal portion of a coil unit according to a first embodiment and a cross-sectional view of a connection portion; [Figure 9] 1 is a cross-sectional view of a connection portion when the crimped portion of the coil unit according to the first embodiment is cylindrical; [Figure 10] Schematic diagram of an induction heating device equipped with a coil unit according to the first embodiment. [Figure 11] Schematic diagram of a non-contact power supply device equipped with a coil unit according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Findings that formed the basis of this disclosure) At the time the inventors arrived at the idea of ​​this disclosure, there was a technology for connecting an aluminum-based coil conductor to a connection terminal, which involved storing solder or brazing filler in a storage section that stores the coil conductor between the coil conductor and the connection terminal, and then applying heat and deforming the storage section with an external force, reducing the volume of the storage section and causing the solder or brazing filler to be ejected between the contact surfaces of the coil conductor and the connection terminal, thereby connecting the coil conductor to the connection terminal (Patent Document 1). In this way, an alloy is formed between the aluminum-based coil conductor and the connection terminal via the solder or brazing filler, and the aluminum-based coil conductor can be prevented from oxidizing due to the solder or brazing coating on its surface, and the formed alloy achieves electrical connection between dissimilar metals.

[0010] Another technology involves arranging the strands of a coil conductor using aluminum wire in a flat three-tiered configuration in a housing of a connection terminal, sandwiching the strands in the housing, and securing them by fusing welding. The boundary between the coil conductor and the housing is then soldered to connect the coil conductor to the connection terminal (Patent Document 2). This prevents peeling of the insulating coating on the coil conductor at the connection between the aluminum coil conductor and the connection terminal, and also prevents stress from being applied to the soldered portion connecting the connection terminal and the coil conductor. This improves the reliability of the connection and provides a stable connection.

[0011] However, the above-mentioned conventional techniques sometimes fail to cover the entire connection between the connection terminal and the coil conductor with solder or brazing filler. For example, in the configuration of Patent Document 1, the amount of solder or brazing filler dispensed to connect the coil conductor and the connection terminal varies depending on the external force that deforms the housing and the amount of solder or brazing filler stored in the housing, so the amount dispensed can be small. In such cases, the connection between the coil conductor and the connection terminal can be made without the entire connection being covered with solder or brazing filler.

[0012] In addition, in the configuration of Patent Document 2, the tip of the coil conductor is soldered to the housing, and the housing is soldered to the coil, but the boundary between the constituent surfaces of the connection terminal that occurs when the coil conductor is sandwiched between the connection terminals and folded back is not soldered, which can cause gaps to form at the boundary due to thermal history initially or during use.

[0013] In a configuration where the entire connection area is not covered with solder or brazing filler, if the connection area comes into contact with an electrolytic medium such as water, the aluminum component of the coil conductor will corrode due to electrolytic corrosion, weakening the connection between the coil conductor and the connection terminal, especially when the potential difference between the coil conductor, which is primarily aluminum, and the connection terminal, which is primarily copper-based metal material, is large (0.65V or more). There were cases where this happened.

[0014] In addition, there are cases where the heat history of the connection portion not covered with solder or brazing material causes an increase in contact resistance (creep phenomenon).

[0015] In addition, to solve the problem of water or other electrolytic media coming into contact with the connection, there is a technology that covers the connection between the aluminum-based coil conductor and the connection terminal made of a copper-based metal material with a rubber-based material such as silicone rubber. This makes it possible to isolate and seal the connection between the coil wire and the connection terminal from the outside when current flows between them, and prevents water or other electrolytic media from coming into contact with the connection, even when the potential difference between the coil wire and the connection terminal is large (0.65V or more), preventing the aluminum-based coil conductor from corroding due to electrolytic corrosion.

[0016] However, when connecting parts are sealed off from the outside with silicone rubber or the like, there are problems with the presence of moisture-containing cavities inside the silicone rubber or with pinholes that allow communication with the outside. In addition, materials such as silicone rubber have low peel strength, and the silicone rubber or the like can easily peel off due to contact during processing or assembly, exposing the connecting parts. Another problem is that the process of curing the silicone rubber or the like increases the work time.

[0017] The inventors have discovered the above problem and have come to form the subject of the present disclosure in order to solve the problem.

[0018] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters or redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art.

[0019] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0020] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to FIGS.

[0021] [1-1.Configuration] In FIG. 1, coil unit 1 is spirally wound and is configured by twisting multiple coil wires 10 together to form a child stranded wire bundle 2, as shown in FIG. 2. As shown in FIG. 3, coil wire 10 is configured from aluminum element wires 11, which are primarily made of aluminum, insulating coating 12 that is insulated by an enamel coating covering aluminum element wire 11, and self-fusing coating 13 that further covers insulating coating 12. The insulating coating 12 and self-fusing coating 13 are removed from coil wires 10 at both ends of coil unit 1, exposing aluminum element wires 11. In this state, child stranded wire bundle 2 is joined by crimping or the like at crimped portion 21 of connection terminal 20, thereby forming connection portion 3 between child stranded wire bundle 2 and connection terminal 20. This electrically connects child stranded wire bundle 2 and connection terminal 20. Note that connection terminal 20 of this embodiment is made of a copper-based metal material that has a combination with aluminum wire 11 that produces an electrochemical potential difference of 0.65 V or more in the electrochemical potential table shown in Fig. 4. Copper-based metal materials have low electrical resistance, which has the effect of making it difficult for the temperature of connection terminal 20 to rise when a current flows through connection terminal 20. In addition, copper-based metal materials are less expensive than other metals with low electrical resistance, such as gold and silver.

[0022] As shown in FIG. 5, the connection terminal 20 has a smooth portion 25 to which solder does not adhere, outside the connection portion 3 to be soldered to the aluminum wire 11. In this embodiment, the boundary between the connection portion 3 to be soldered of the connection terminal 20 and the smooth portion 25 is referred to as a solder bath boundary line 26. The connection terminal 20 also has a screw fixing hole 27 (an example of a screw fastening hole in the present disclosure) in the smooth portion 25. The screw fixing hole 27 is provided in a direction away from the connection portion 3 with respect to the solder bath boundary line 26. The solder 4 to be integrally joined to the aluminum wire 11 is composed of a metal material whose main component is a tin-based metal and has an electrochemical potential difference of 0.45 V in the electrochemical potential table of FIG. 4.

[0023] The ultrasonic soldering process in this embodiment will be described with reference to Fig. 6. The connection portion 3 between the child stranded wire bundle 2 and the connection terminal 20 is clamped and fixed between an ultrasonic tip 30 and a reflector 31, and is immersed in a solder bath 32. The connection portion 3 is subjected to ultrasonic vibrations emitted by the ultrasonic tip 30 and the reflector 31, and is ultrasonically soldered.

[0024] The ultrasonically soldered connection 3 will be described with reference to FIGS.

[0025] 7 and 8, the area of ​​region B shown in the plan view and cross section A-A is soldered. Accordingly, while maintaining the linear shape, the gaps between the multiple aluminum wires 11 and the gaps inside the multiple aluminum wires 11 and the crimped portion 21, as well as the crimped opening 22, entrance opening 23, and exit opening 24 of the connection terminal 20 are all soldered. This allows the solder 4 to cover the entire connection portion 3 where the child stranded wire bundle 2 and the connection terminal 20 are electrically connected, and the connection portion 3 can be isolated and sealed from the outside.

[0026] The crimped portion 21 shown in Fig. 7 is configured so that both ends face each other, while the crimped portion 21 shown in Fig. 8 is configured so that both ends overlap one another. The crimped portion 21 of the connection terminal 20 may also be formed in a cylindrical shape as shown in Fig. 9. In this case, the crimped opening 22 is not formed, but the inlet opening 23 and the outlet opening 24 are configured so that they are all covered with the solder 4.

[0027] The coil unit 1 of this embodiment configured as described above can be used in an induction heating device 40 that includes a high-frequency power supply device 42 that supplies high-frequency alternating current to the coil unit 1.

[0028] The configuration of the induction heating device 40 will be described with reference to FIG.

[0029] Induction heating device 40 includes top plate 41 and coil unit 1 below it. Coil unit 1 is connected by fastening lead wires 43, which are connected to high-frequency power supply device 42 via screw fixing holes 27 of connection terminal 20, with screws 44. High-frequency power supply device 42 is connected to power source 46 via outlet 45.

[0030] [1-2. Operation] The operation of the induction heating device 40 configured as above will now be described.

[0031] When a user places cooking pot 47 containing an object to be heated on top plate 41 and turns on a switch (not shown) of induction heating device 40, the alternating current supplied from power source 46 is converted into high-frequency current by high-frequency power supply device 42, and the high-frequency current is supplied to coil unit 1. As a result, cooking pot 47 is induction heated.

[0032] When a high-frequency current is supplied to the coil unit 1, a high current of several tens of amperes flows through the connection terminal 20.

[0033] [1-3. Effects, etc.] As described above, in this embodiment, the coil unit 1 includes the coil wire 10, which is primarily aluminum and covered with the insulating coating 12, the child stranded wire bundle 2 formed by twisting a plurality of coil wires 10, the connection terminal 20, which is primarily made of a copper-based metal material and has a crimped portion 21 that joins the child stranded wire bundle 2, and the connection portion 3, which is formed by partially removing the insulating coating 12 from the portion of the coil wire 10 that comes into contact with the connection terminal 20 and joining it to the crimped portion 21, thereby electrically connecting the child stranded wire bundle 2 and the connection terminal 20. The connection portion 3 is configured so that it is entirely covered with solder 4.

[0034] This allows the connection portion 3, where the child stranded wire bundle 2 of the coil unit 1 is electrically connected to the connection terminal 20, to be isolated from the outside and sealed. Therefore, the connection portion 3 does not come into contact with an electrolytic medium such as water, so even if the connection terminal 20 is made of a dissimilar metal to the aluminum-based coil wire 10 and there is a potential difference of 0.65 V or more, galvanic corrosion of the aluminum at the connection portion 3 over time can be suppressed. Furthermore, the connection portion 3 can be firmly and integrally joined by mechanical joining. Therefore, the contact resistance at the connection portion 3 is substantially zero, and an increase in the contact resistance of the connection portion due to thermal history (creep phenomenon) can be suppressed. These features prevent breakage and abnormal heat generation at the connection portion 3, providing a safe and durable coil unit 1.

[0035] Furthermore, as in this embodiment, the coil unit 1 may be configured so that the multiple coil wires 10 housed inside the crimped portion 21 and the opening of the crimped portion 21 are covered with solder 4 by ultrasonic soldering.

[0036] This isolates and seals the crimped opening 22, inlet opening 23, and outlet opening 24 of crimped portion 21 of connection terminal 20, through which a high current flows, from the outside, and also prevents the openings from becoming mechanically loose and deforming or opening due to thermal history. As a result, it is possible to achieve almost zero electrolytic corrosion of aluminum over time in connection portion 3 and zero contact resistance in connection portion 3, and it is also possible to suppress an increase in contact resistance in connection portion 3 due to thermal history (creep phenomenon).

[0037] Furthermore, as in this embodiment, the coil unit 1 may be configured such that the connection terminal 20 has a smooth portion 25 between the solder bath boundary line 26 for soldering to the multiple coil wires 10 and the screw fixing hole 27.

[0038] This prevents the solder 4 from adhering to the periphery of the screw fixing hole 27 for fastening the connection terminal 20 and the lead wire 43. This prevents the solder 4 from adhering to the area where the screw 44 is fastened, causing unevenness, and ensures a sufficient contact area between the connection terminal 20, the lead wire 43, and the screw 44. This prevents the screw 44 from loosening and abnormal heat generation due to a reduced contact area.

[0039] Furthermore, as in this embodiment, the coil unit 1 may be mounted on an induction heating device 40 that includes a high-frequency power supply device 42 that supplies high-frequency alternating current to the coil unit 1.

[0040] This allows the user to use the induction heating device 40 in a safe and durable manner. (Embodiment 2) Hereinafter, the second embodiment will be described with reference to FIG. [2-1.Configuration] FIG. 11 illustrates the configuration of a contactless power supply device 50 according to the second embodiment.

[0041] The non-contact power supply device 50 includes a pickup unit 51 and a coil unit 1 below the pickup unit 51. The coil unit 1 is connected to the high frequency power supply device 52 via the screw fixing hole 27 of the connection terminal 20. The pickup unit 51 is connected to a lead wire 53 connected to the pickup unit 51 by fastening with a screw 54. The pickup unit 51 is electrically connected to a supply device 56 via a power supply line 55. [2-2. Operation] The operation of the contactless power supply device 50 configured as above will be described below.

[0042] The coil unit 1 induces AC power through electromagnetic induction by the high frequency current supplied from the high frequency power supply device 52. The pickup unit 51 converts the AC power excited in the coil unit 1 into AC voltage or DC voltage, which is supplied to the supply device 56 via the power supply line 55 and stored.

[0043] For example, when a vehicle carrying a powered object is placed on the supplying device 56, the powered object is charged.

[0044] When a high-frequency current is supplied to the coil unit 1, a high current of several tens of amperes flows through the connection terminal 20. [2-3. Effects, etc.] As described above, in this embodiment, the coil unit 1 may be mounted on a contactless power supply device 50 including a high-frequency power supply device 52 that supplies a high-frequency alternating current to the coil unit 1. [Industrial Applicability]

[0045] The present disclosure is applicable to a coil unit formed using a coil wire whose main component is aluminum, and to a dielectric heating device or a non-contact power supply device using the coil unit. Specifically, the present disclosure is applicable to an induction heating (IH) cooking heater, an induction heating (IH) rice cooker, a non-contact power supply device for outdoor charging, etc. [Explanation of symbols]

[0046] 1 coil unit 2-ply twisted wire bundle 3 Connection 4 Solder 10 Coil wire 11 Aluminum wire 12 Insulation coating 13 Self-adhesive coating 20 Connection terminal 21 Crimping part 22 Crimped opening 23 Inlet opening 24 Exit opening 25 Smooth section 26 Solder bath boundary line 27 screw fixing holes 30 ultrasonic tips 31 Reflector 32 Solder bath 40 Induction heating device 41 Top Plate 42, 52 High frequency power supply equipment 43, 53 lead wire 44, 54 screws 45 outlets 46 Power supply 47 Cooking Pot 50 Non-contact power supply device 51 Pickup unit 55 Power line 56 Feeding device

Claims

1. A coil wire whose main component is aluminum covered with an insulating coating, a stranded wire bundle formed by twisting a plurality of the coil wires; a connection terminal made mainly of a copper-based metal material and having a crimping portion for joining the child stranded wire bundle; a connection portion that electrically connects the child stranded wire bundle and the connection terminal by partially removing the insulating coating from a portion of the coil wire that comes into contact with the connection terminal and joining the portion to the crimped portion, Covering all of the connection portions with solder; Coil unit.

2. By ultrasonic soldering, A plurality of the coil wires housed inside the crimped portion; The opening of the crimped portion is covered with solder. The coil unit according to claim 1.

3. The connection terminal has a smooth portion between a solder bath boundary line for soldering to the plurality of coil wires and a screw fixing hole. The coil unit according to claim 2.

4. A coil unit according to any one of claims 1 to 3; a high frequency power supply device that supplies a high frequency alternating current to the coil unit; An induction heating device equipped with:

5. A coil unit according to any one of claims 1 to 3; a high frequency power supply device that supplies a high frequency alternating current to the coil unit; A non-contact power supply device comprising:

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