JP7802038B2 - induction heating cooker - Google Patents

Description

This technology relates to an induction cooking device that heats and cooks food.

Conventionally, induction cookers have been known in which a coil is formed by winding a thin metal film around the surface of an insulating substrate (see, for example, Patent Document 1). The induction cooker in Patent Document 1 aims to efficiently heat the object to be heated by providing coils at both the center and the periphery of the heating section.

Japanese Patent Application Laid-Open No. 2022-043697

However, in the induction heating cooker of Patent Document 1, the coils located in the center and periphery are connected, and therefore cannot be controlled independently. Therefore, with the induction heating cooker of Patent Document 1, uneven heating may occur depending on the size and placement of the heated object.

This disclosure has been made to solve the above-mentioned problems, and aims to prevent uneven heating in induction cooking devices that have coils formed by winding a conductor around a substrate.

The induction heating cooker according to the present disclosure comprises an insulating multi-layer substrate, an inner coil formed by winding a conductor across two layers of the substrate, an outer coil formed by winding a conductor across two layers of the substrate and formed outside the outermost periphery of the inner coil, and a power supply substrate to which the inner coil and the outer coil are independently connected , wherein the inner coil includes a first coil formed by winding a conductor around a first layer of the substrate, and a second coil electrically connected to the first coil and formed by winding a conductor around a second layer of the substrate, The outer coil includes a third coil formed by winding a conductor around a first layer and located outside the outer periphery of the first coil, and a fourth coil formed by winding a conductor around a second layer and electrically connected to the third coil and located outside the outer periphery of the third coil; the substrate has a first substrate and a second substrate provided below the first substrate, the second substrate being located at the bottom of the substrate, the first layer being a layer formed on the upper surface of the first substrate, and the second layer being a layer formed on the lower surface of the second substrate .

In the induction cooking device disclosed herein, the inner coil and outer coil are independently connected to the power supply board. Therefore, the induction cooking device can independently drive the inner coil and outer coil, thereby preventing uneven heating.

1 is a perspective view of an induction heating cooker according to a first embodiment; 3 is a diagram for explaining the configuration inside a main body case of the induction heating cooker of the first embodiment. FIG. 1 is a schematic diagram showing an internal configuration of an induction heating cooker according to a first embodiment. FIG. 5 is a diagram for explaining the positional relationship between the induction heating unit and the top plate according to the first embodiment. FIG. 1 is a diagram for explaining the configuration of an induction heating unit according to Embodiment 1. FIG. FIG. 2 is a diagram showing a substrate according to the first embodiment as viewed from above. FIG. 2 is a bottom view of the substrate according to the first embodiment. 4A and 4B are diagrams showing an inner connection terminal according to the first embodiment; 5A to 5C are diagrams for explaining a method of connecting an inner connection terminal and a lead wire according to the first embodiment. FIG. 2 is a view of the substrate according to the first embodiment as viewed from the right. 2A to 2C are diagrams for explaining the structure of a substrate according to the first embodiment. FIG. 2 is a diagram showing the upper layer of a substrate according to the first embodiment. FIG. 2 is a diagram showing an intermediate layer of a substrate according to the first embodiment. FIG. 2 is a diagram showing a lower layer of a substrate according to the first embodiment. 3 is a diagram for explaining a power supply system by a power supply board 20. FIG. FIG. 10 is a top view of a substrate according to a second embodiment. FIG. 10 is a bottom view of the substrate according to the second embodiment. FIG. 10 is a view of the substrate according to the second embodiment as viewed from the right. FIG. 10 is a diagram showing the upper layer of a substrate according to a second embodiment. FIG. 10 is a diagram showing an intermediate layer of a substrate according to a second embodiment. FIG. 10 is a diagram showing the lower layer of a substrate according to a second embodiment. FIG. 11 is a top view of a substrate according to a third embodiment. FIG. 11 is a bottom view of the substrate according to the third embodiment. FIG. 11 is a view of the substrate according to the third embodiment as viewed from the right. FIG. 10 is a diagram showing the upper layer of a substrate according to a third embodiment. FIG. 10 is a diagram showing an intermediate layer of a substrate according to a third embodiment. FIG. 10 is a diagram showing the lower layer of a substrate according to a third embodiment. 3 is a diagram for explaining a power supply system by a power supply board 20. FIG. FIG. 10 is a top view of a substrate according to a fourth embodiment. FIG. 10 is a bottom view of the substrate according to the fourth embodiment. FIG. 10 is a cross-sectional view showing a substrate and ferrite according to a fourth embodiment. FIG. 10 is a cross-sectional view showing a substrate and ferrite according to a fourth embodiment. 10A and 10B are diagrams showing a substrate and a jig according to a fourth embodiment; FIG. 10 is a diagram showing a substrate set in a jig according to a fourth embodiment. FIG. 10 is a diagram showing a substrate set in a jig according to a fourth embodiment.

Embodiment 1.
FIG. 1 is a perspective view of an induction cooking appliance 1 according to a first embodiment. As shown in FIG. 1, the induction cooking appliance 1 according to the first embodiment is a cooking appliance that uses electromagnetic induction to heat a cooking container and an object to be heated (food). A main body case 2 of the induction cooking appliance 1 houses an appliance that performs cooking. Note that arrows indicating directions are shown in the following figures as appropriate. The X direction is the right direction when the induction cooking appliance 1 is installed. The Y direction is the upward direction when the induction cooking appliance 1 is installed. The Z direction is the forward direction when the induction cooking appliance 1 is installed.

The top plate 3, which serves as the cooking top, is placed on top of the main body case 2, and a metal cooking container containing an object to be heated is placed on it. The top plate 3 is made, for example, of crystallized glass, which is transparent to infrared rays. The top plate 3 in embodiment 1 corresponds to the induction heating unit 10 described below, and has two heating areas 4, which are regions where the cooking container and object to be heated (hereinafter referred to as the object to be heated) placed on the surface of the top plate 3 can be induction heated. The boundaries of the heating areas 4 are indicated to the user by a circular pattern printed on the back of the top plate 3.

The induction cooker 1 in embodiment 1 also has an operation display panel 7 on the front top surface. The operation display panel 7 accepts operations for setting various cooking conditions and displays the cooking condition settings and information indicating abnormalities. Furthermore, the induction cooker 1 in embodiment 1 has a grill cooker 5 in the lower left when viewed from the front. The grill cooker 5 is installed on the left side of the front surface of the induction cooker 1 and has a grill door 6 for opening and closing the grill chamber 5a (see Figure 3).

Figure 2 is a diagram illustrating the internal configuration of the main body case 2 of the induction cooking appliance 1 of embodiment 1. Figure 2 shows the main body case 2 without the top plate 3. The main body case 2 of the induction cooking appliance 1 has an air intake port 8 at the rear for taking in air from the outside to be sent to the grill chamber 5a of the grill cooker 5. The main body case 2 also has an exhaust port 9 for discharging smoke and other air generated by the heated items in the grill chamber 5a.

Furthermore, the induction heating cooker 1 in embodiment 1 has two induction heating units 10. The induction heating units 10 have coils, which will be described later, and inductively heat an object to be heated placed in the heating area 4 of the top plate 3. Here, the number of induction heating units 10 that the induction heating cooker 1 has is not limited to two.

Figure 3 is a schematic diagram showing the internal configuration of the induction cooking appliance 1 according to embodiment 1. Figure 3 shows the internal configuration of the induction cooking appliance 1 as viewed from the front. A power supply board 20 is installed inside the main body case 2. The power supply board 20 has components such as semiconductor integrated circuits, resistors, capacitors, and transistors fixed thereto, and has a circuit formed by wiring the components together with copper foil.

The power supply board 20 supplies power from a commercial power source (not shown) to the induction heating unit 10. Specifically, the power supply board 20 first converts and rectifies the AC power supplied from the commercial power source (not shown) into DC power. The converted DC power is then converted into AC power with a frequency based on the cooking condition settings set via the operation display panel 7, and supplied to the induction heating unit 10 via the lead wires 12. The lead wires 12 are twisted wires with an insulating coating.

Figure 4 is a diagram illustrating the positional relationship between the induction heating unit 10 and the top plate 3 according to embodiment 1. In Figure 4, arrows indicate the air flow. The induction heating unit 10 is supported from its rear by an elastic spring (not shown), which presses it against the rear surface of the top plate 3 and secures it in place. As shown in Figure 4, the induction heating unit 10 is secured at a fixed distance from the top plate 3 by a spacer 11. The spacer 11 is an elastic material such as rubber. While not particularly limited, the distance between the substrate 102 and the top plate 3 may be approximately 3 mm to 4 mm, for example. Providing a gap between the substrate 102 and the top plate 3 reduces the impact of heat from the heated object on the coil on the substrate 102, as described below. Furthermore, air flowing in through the air intake 8 passes over the coil on the substrate 102, thereby cooling the coil. Furthermore, damage to the printing on the rear surface of the top plate 3 caused by protrusions such as screws protruding from the substrate 102 can be prevented. The spacer 11 stabilizes the distance between the top plate 3 and a sensor (not shown) that measures the temperature of the object to be heated, improving the accuracy of temperature detection.

Figure 5 is a diagram illustrating the configuration of the induction heating unit 10 according to embodiment 1. Figure 5 is an exploded view of the induction heating unit 10. The induction heating unit 10 according to embodiment 1 includes a magnetic shielding member 101, a substrate 102, ferrite 103, a holding member 104, and a fixing screw 105.

The magnetic shielding member 101 is a plate-shaped member made of non-magnetic metal that prevents the magnetic field generated in the inner coil 30 and outer coil 40 (see Figure 6) from leaking outside the heating area 4. The magnetic shielding member 101 forms the outer shell of the induction heating unit 10, and is shaped to expose the inner coil 30 and outer coil 40. The magnetic shielding member 101 also sandwiches the holding member 104 and the substrate 102, preventing warping of the substrate 102. Note that the magnetic shielding member 101 is not a component that must be installed.

The substrate 102 is a printed circuit board on which the inner coil 30 and outer coil 40 (see Figure 6) are formed by printing. The substrate 102 is made of an insulating material. The substrate 102 is heat-resistant because it receives radiant heat from the object to be heated. The inner coil 30 and outer coil 40 may be protected by applying a solder resist to the substrate 102. In the following description, the surface of the substrate 102, which is a plate-shaped member, facing upward is referred to as the front surface, and the surface opposite the front surface is referred to as the back surface, based on the state in which the induction cooking appliance 1 is installed.

The appearance of the substrate 102, inner coil 30, and outer coil 40 will be briefly described using Figures 6 to 10. Figure 6 is a top view of the substrate 102 according to embodiment 1. Figure 7 is a bottom view of the substrate 102 according to embodiment 1. As shown in Figure 6, the substrate 102 is provided with the inner coil 30 and outer coil 40. The inner coil 30 and outer coil 40 are thin-film conductors such as copper foil, and are spirally wound around the substrate 102. Because the inner coil 30 and outer coil 40 are formed by printing, no jig for winding copper wire is required during manufacturing, allowing for a high degree of freedom in the coil shape that can be fabricated. When power is supplied from the power supply board 20 via the lead wires 12, the inner coil 30 and outer coil 40 generate a magnetic field, generating eddy currents due to electromagnetic induction. The inner coil 30 is located in the center of the surface of the substrate 102. The outer coil 40 is formed concentrically with the inner coil 30. The innermost periphery of the outer coil 40 is positioned further outward on the surface of the substrate 102 than the outermost periphery of the inner coil 30.

As shown in Figure 7, connection portions 50-52 are provided on the back surface of the substrate 102. The connection portion 50 is made of a thin-film conductor such as copper foil. The connection portion 50 is electrically connected to the inner coil 30, as will be described in detail below. An inner connection terminal 300 to which the lead wire 12 is connected is also attached to the connection portion 50 by soldering or the like. The inner connection terminal 300 is made of metal and is an input terminal that connects the lead wire 12 and the connection portion 50 and passes electricity from the power supply substrate 20 to the inner coil 30.

Here, a method for connecting the inner connection terminal 300 and the lead wire 12 will be described using Figures 8 and 9. Figure 8 is a diagram showing the inner connection terminal 300 according to embodiment 1. Figure 9 is a diagram for explaining a method for connecting the inner connection terminal 300 and the lead wire 12 according to embodiment 1. As shown in Figure 8, the inner connection terminal 300 has a screw hole 300a formed in its center. As shown in Figure 9, the tab terminal is fixed to the inner connection terminal 300 by tightening a terminal screw 12b into the inner connection terminal 300 and a screw hole (not shown) in the terminal portion 12a connected to the end of the lead wire 12. This electrically connects the lead wire 12 and the inner connection terminal 300. This also electrically connects the power supply board 20 and the inner coil 30.

Returning to Figure 7, the connection portion 51 is made of a thin-film conductor such as copper foil. The connection portion 51 is electrically connected to the outer coil 40, as will be described in detail below. An outer connection terminal 400, to which the lead wire 12 is connected, is attached to the connection portion 51 by soldering or the like. The outer connection terminal 400 is made of metal and serves as an input terminal for connecting the lead wire 12 to the connection portion 51 and passing electricity from the power supply board 20 to the outer coil 40. The configuration of the outer connection terminal 400 and the method of connecting the outer connection terminal 400 to the lead wire 12 are similar to those of the inner connection terminal 300, and therefore will not be described here. In this way, the inner coil 30 and the outer coil 40 are independently connected to the power supply board 20.

The connection portion 52 is made of a thin-film conductor such as copper foil. The connection portion 52 is electrically connected to the inner coil 30 and outer coil 40, as will be described in detail below. A common connection terminal 500, to which the lead wire 12 is connected, is attached to the connection portion 52 by solder or the like. The common connection terminal 500 is made of metal and connects the lead wire 12 to the connection portion 52 to pass electricity from the inner coil 30 and outer coil 40 to the power supply board 20. The configuration of the common connection terminal 500 and the method of connecting the common connection terminal 500 to the lead wire 12 are similar to those of the inner connection terminal 300 and outer connection terminal 400, so further explanation is omitted.

Figure 10 is a right-side view of the substrate 102 according to embodiment 1. As shown in Figures 7 and 10, the inner connection terminals 300, outer connection terminals 400, and common connection terminals 500 are arranged side by side along the same side of the substrate 102. Arranging the inner connection terminals 300, outer connection terminals 400, and common connection terminals 500 side by side allows for efficient connection of the lead wires 12. Furthermore, when the outer coil 40, located on the front surface, is projected onto the back surface, the inner connection terminals 300, outer connection terminals 400, and common connection terminals 500 are all located outside the outermost periphery of the outer coil 40. This allows the power supply substrate 20 to be connected to the inner connection terminals 300, outer connection terminals 400, and common connection terminals 500 without having to route the lead wires 12 beneath the inner coil 30 and outer coil 40. This allows for efficient application of cooling air to the inner coil 30 and outer coil 40.

Returning to Figure 5, the ferrite 103 is a magnetic material that guides the magnetic flux generated by the magnetism in the inner coil 30 and outer coil 40 via the top plate 3 to the object to be heated located above the induction heating unit 10. The ferrite 103 also suppresses magnetic flux leakage downward from the inner coil 30 and outer coil 40. By suppressing magnetic flux leakage, the ferrite 103 prevents various boards and control devices (not shown) from malfunctioning due to magnetism. In embodiment 1, eight ferrites 103 are arranged so that their longitudinal directions are aligned with the radial direction of the board 102.

The holding member 104 is a member that holds the substrate 102 and the ferrite 103 sandwiched between the substrate 102. The holding member 104 is also fixed to the substrate 102 with fixing screws 105, preventing the substrate 102 from warping due to heat.

In addition, the inner connection terminal 300, outer connection terminal 400, and common connection terminal 500 are exposed at the bottom of the induction heating unit 10 through through holes (not shown) formed in the holding member 104, allowing connection of the lead wire 12.

The fixing screws 105 secure the substrate 102, holding member 104, and magnetic shielding member 101 together. By fastening the substrate 102, holding member 104, and magnetic shielding member 101 together with the fixing screws 105, adhesive is not required to secure the substrate 102 when manufacturing the induction heating unit 10, making disassembly easier. Here, the fixing screws 105 are made of a non-magnetic material.

Here, using Figures 11 to 14, a detailed description will be given of the inner coil 30, the outer coil 40, and the conductor patterns of the connection portions for connecting them to the respective connection terminals. Figure 11 is a diagram for explaining the structure of the substrate 102 according to embodiment 1. Figure 11 shows a vertical cross section of the substrate 102. As shown in Figure 11, the substrate 102 has a first substrate 102a and a second substrate 102b disposed below the first substrate 102a. The first substrate 102a and the second substrate 102b are non-conductive insulating layers of the multilayer substrate 102. The conductor layer formed on the surface of the first substrate 102a is referred to as the upper layer 111, the conductor layer formed on the back surface of the second substrate 102b is referred to as the lower layer 113, and the conductor layer formed between the first substrate 102a and the second substrate 102b is referred to as the middle layer 112. Note that the conductor layer refers to the entire conductor pattern formed on one side of the insulating layer. As shown in FIG. 11 , the inner coil 30 is formed across the upper layer 111 and middle layer 112. Furthermore, connection portions 50 and 52 for connecting the inner coil 30 to each connection terminal are formed on the lower layer 113. Although not shown, the outer coil 40 is similar to the inner coil 30. That is, the outer coil 40 is also formed across the upper layer 111 and middle layer 112. Furthermore, connection portions 51 and 52 for connecting the outer coil 40 to each connection terminal are formed on the lower layer 113. In the first embodiment, the upper layer 111 corresponds to the "first layer" of this disclosure, and the middle layer 112 corresponds to the "second layer" of this disclosure.

The inner coil 30 and outer coil 40 on each layer are connected to the connection points by vias. A via is an opening that penetrates the substrate 102, with the area surrounding the opening plated with metal. Vias V1 to V3 shown in Figure 11 indicate different types of vias. Via V1, which penetrates the first substrate 102a and the second substrate 102b, electrically connects the conductor on the upper layer 111 to the conductor on the lower layer 113. Via V2, which penetrates only the first substrate 102a, electrically connects the conductor on the upper layer 111 to the conductor on the middle layer 112. Via V3, which penetrates only the second substrate 102b, electrically connects the conductor on the middle layer 112 to the conductor on the lower layer 113.

Figure 12 is a diagram showing the upper layer 111 of the substrate 102 according to embodiment 1. Figure 13 is a diagram showing the middle layer 112 of the substrate 102 according to embodiment 1. Figure 14 is a diagram showing the lower layer 113 of the substrate 102 according to embodiment 1. Figures 12 to 14 all show the substrate 102 as viewed from above. The configuration formed in each layer and their electrical connections will be explained below.

First, we will explain the structure formed on each layer, starting from the top layer 111. As shown in FIG. 12, the first coil 31, which is part of the inner coil 30, is formed on the top layer 111 by winding a thin-film conductor. The first coil 31 is wound from via 311 to via 312. Via 311 is one of the vias V1 connecting the top layer 111 and the lower layer 113. Via 312 is one of the vias V2 connecting the top layer 111 and the middle layer 112. Also, on the top layer 111, the third coil 41, which is part of the outer coil 40, is formed by winding a thin-film conductor. The third coil 41 is wound from via 411 to via 412. Via 411 is one of the vias V1 connecting the top layer 111 and the lower layer 113. Via 412 is one of the vias V2 connecting the top layer 111 and the middle layer 112.

As shown in FIG. 13, the second coil 32, which is part of the inner coil 30, is formed on the middle layer 112 by winding a thin-film conductor. The second coil 32 is wound from via 312 to via 313. Via 313 is one of vias V3 that connect the middle layer 112 and the lower layer 113. Also, the fourth coil 42, which is part of the outer coil 40, is formed on the middle layer 112 by winding a thin-film conductor. The fourth coil 42 is wound from via 412 to via 413. Via 413 is one of vias V3 that connect the middle layer 112 and the lower layer 113.

As shown in Figure 14, connection portions 50-52 are formed on the lower layer 113. Connection portion 50 is elongated in the front-to-rear direction and connects the inner connection terminal 300 and via 311 described above. Connection portion 51 is approximately rectangular and connects the inner connection terminal 300 and via 411 described above. Connection portion 52 is elongated in the front-to-rear direction and connects the common connection terminal 500 and vias 313 and 413 described above.

Next, the electrical connections of the components formed on each layer will be explained along the flow of electricity. Note that parentheses indicate which conductor layer each conductor constitutes. For the inner coil 30, power supplied from the power supply board 20 flows in the following order: inner connection terminal 300, connection portion 50 (lower layer 113), via 311, first coil 31 (upper layer 111), via 312, second coil 32 (middle layer 112), via 313, connection portion 52 (lower layer 113), and common connection terminal 500. For the outer coil 40, power supplied from the power supply board 20 flows in the following order: outer connection terminal 400, connection portion 51 (lower layer 113), via 411, third coil 41 (upper layer 111), via 412, fourth coil 42 (middle layer 112), via 413, connection portion 52 (lower layer 113), and common connection terminal 500.

Figure 15 is a diagram illustrating the power supply system using the power supply board 20. As shown in Figure 15, the inner coil 30 and outer coil 40 are individually connected to the power supply board 20 by lead wires 12 and are individually supplied with power. Therefore, the induction cooking device 1 can drive one of the inner coil 30 and outer coil 40 and stop the other. For example, if the object to be heated is small, heating can be performed using only the inner coil 30, and if the object to be heated is large, heating can be performed using only the inner coil 30 and outer coil 40, thereby heating the object evenly. Alternatively, the induction cooking device 1 can drive one coil at high frequency and the other at low frequency. In this way, the induction cooking device 1 can drive the inner coil 30 and outer coil 40 independently.

As described above, according to the induction cooking device 1 of embodiment 1, the inner coil 30 and the outer coil 40 are independently connected to the power supply board 20. Therefore, the induction cooking device 1 can independently drive the inner coil 30 and the outer coil 40. This allows the induction cooking device 1 to prevent uneven heating.

Embodiment 2.
The induction heating cooker 1 of the second embodiment differs from that of the first embodiment in the conductor patterns of the inner coil 30A and the outer coil 40A. Below, the differences from the first embodiment will be described, and a description of the commonalities will be omitted.

First, the external appearance of the substrate 102, inner coil 30A, and outer coil 40A of embodiment 2 will be briefly described using Figures 16 to 18. Figure 16 is a view of the substrate 102 of embodiment 2 as seen from above. Figure 17 is a view of the substrate 102 of embodiment 2 as seen from below. As shown in Figure 16, the inner coil 30A and outer coil 40A are provided on the substrate 102.

As shown in Figure 17, the back surface of the substrate 102 is provided with the inner coil 30A, outer coil 40A, and connection portions 53-55. The connection portion 53 is made of a thin-film conductor such as copper foil. The connection portion 53 is electrically connected to the inner coil 30A, as will be described in detail later. Furthermore, the inner connection terminal 300, to which the lead wire 12 is connected, is attached to the connection portion 53 by soldering or the like.

The connection portion 54 is made of a thin-film conductor such as copper foil. The connection portion 54 is electrically connected to the outer coil 40A, as will be described in detail below. The outer connection terminal 400, to which the lead wire 12 is connected, is also attached to the connection portion 54 by soldering or the like.

The connection portion 55 is made of a thin-film conductor such as copper foil. The connection portion 55 is electrically connected to the outer coil 40A and the inner coil 30A, as will be described in detail later. A common connection terminal 500, to which the lead wire 12 is connected, is also attached to the connection portion 55 by soldering or the like.

Figure 18 is a view of the substrate 102 according to embodiment 2 as viewed from the right. As shown in Figures 17 and 18, the inner connection terminal 300, outer connection terminal 400, and common connection terminal 500 are arranged side by side along the same side of the substrate 102. Furthermore, the inner connection terminal 300, outer connection terminal 400, and common connection terminal 500 are all located outside the outermost periphery of the outer coil 40A.

Now, using Figures 19 to 21, we will provide a detailed description of the inner coil 30A, outer coil 40A, and the conductor patterns of the connections for connecting them to the respective connection terminals. Figure 19 is a diagram showing the upper layer 111 of the substrate 102 according to embodiment 2. Figure 20 is a diagram showing the middle layer 112 of the substrate 102 according to embodiment 2. Figure 21 is a diagram showing the lower layer 113 of the substrate 102 according to embodiment 2. Figures 19 to 21 all show diagrams of the substrate 102 as viewed from above. Below, we will explain the configuration formed on each layer and their electrical connections.

First, we will explain the structure formed on each layer, starting from the top layer 111. As shown in Figure 19, the first coil 31A, which is part of the inner coil 30A, is formed on the top layer 111 by winding a thin-film conductor. The first coil 31A is wound from via 322 to via 323. Via 322 is one of the vias V2 connecting the top layer 111 and the middle layer 112. Via 323 is one of the vias V1 connecting the top layer 111 and the lower layer 113. The third coil 41A, which is part of the outer coil 40A, is also formed on the top layer 111 by winding a thin-film conductor. The third coil 41A is wound from via 421 to via 422. Via 421 is one of the vias V1 connecting the top layer 111 and the lower layer 113. Via 422 is one of vias V1 that connects upper layer 111 and lower layer 113.

As shown in Figure 20, connection portions 53a and 53b are formed on the middle layer 112. Connection portion 53a is elongated in the front-to-rear direction and connects via 321 and via 322. Via 321 is one of vias V3 that connect the middle layer 112 and the lower layer 113. Connection portion 53b is elongated in the front-to-rear direction and connects via 324 and via 325. Via 324 is one of vias V3 that connect the middle layer 112 and the lower layer 113. Via 325 is one of vias V3 that connect the middle layer 112 and the lower layer 113.

As shown in FIG. 21, the second coil 32A, which is part of the inner coil 30A, is formed on the lower layer 113 by winding a thin-film conductor. The second coil 32A is wound from via 323 to via 324. The fourth coil 42A, which is part of the outer coil 40A, is formed on the middle layer 112 by winding a thin-film conductor. The fourth coil 42A is wound from via 412 to connection portion 55. Connection portions 53 to 55 are also formed on the lower layer 113. Connection portion 53 is approximately rectangular and connects the inner connection terminal 300 to via 321. Connection portion 54 is approximately rectangular and connects the outer connection terminal 400 to via 421. Connection portion 55 is elongated in the left-right direction and connects the common connection terminal 500, the outer coil 40A, and via 325.

Next, the electrical connections of the components formed on each layer will be explained along the flow of electricity. Note that parentheses indicate which conductor layer each conductor constitutes. For the inner coil 30A, power supplied from the power supply board 20 flows in the following order: inner connection terminal 300, connection portion 53 (lower layer 113), via 321, connection portion 53a (middle layer 112), via 322, first coil 31A (upper layer 111), via 323, second coil 32A (lower layer 113), via 324, connection portion 53b (middle layer 112), via 325, connection portion 55 (lower layer 113), and common connection terminal 500. For the outer coil 40A, power supplied from the power supply board 20 flows in the following order: outer connection terminal 400, connection portion 54 (lower layer 113), via 421, third coil 41A (upper layer 111), via 422, fourth coil 42A (lower layer 113), connection portion 55 (lower layer 113), and common connection terminal 500.

In the second embodiment, the inner coil 30A and the outer coil 40A are also individually connected to the power supply board 20 by lead wires 12, and are individually supplied with power. Therefore, the induction cooking device 1 can drive one of the inner coil 30A and the outer coil 40A and stop the other. Alternatively, the induction cooking device 1 can drive one at high frequency and the other at low frequency. In this way, the induction cooking device 1 can drive the inner coil 30A and the outer coil 40A independently.

As described above, according to the induction heating cooker 1 of embodiment 2, similar to embodiment 1, the inner coil 30A and the outer coil 40A are independently connected to the power supply board 20. Therefore, the induction heating cooker 1 can independently drive the inner coil 30A and the outer coil 40A, thereby preventing uneven heating.

Furthermore, according to embodiment 2, the inner coil 30A and the outer coil 40A are provided on the upper layer 111 and the lower layer 113, i.e., on the front surface of the first substrate 102a and the back surface of the second substrate 102b. Therefore, the inner coil 30A and the outer coil 40A, which generate a large amount of heat, can be cooled more efficiently than when the inner coil 30A and the outer coil 40A are provided on the middle layer 112.

Note that the inner coil 30A and outer coil 40A in embodiment 2 are formed across the upper layer 111 and the lower layer 113. Therefore, in embodiment 2, the upper layer 111 corresponds to the "first layer" in this disclosure, and the lower layer 113 corresponds to the "second layer" in this disclosure.

Embodiment 3.
The induction heating cooker 1 of the third embodiment differs from the first embodiment in that it has an inner coil 30, a rear coil 60, a front coil 70, a left coil 80, and a right coil 90. Below, the differences from the first embodiment will be described, and a description of the commonalities with the first embodiment will be omitted.

First, using Figures 22 to 24, we will briefly explain the appearance of the substrate 102, and the inner coil 30, rear coil 60, front coil 70, left coil 80, and right coil 90 of embodiment 3. Figure 22 is a top view of the substrate 102 of embodiment 3. Figure 23 is a bottom view of the substrate 102 of embodiment 3. As shown in Figure 22, the substrate 102 is provided with the inner coil 30, rear coil 60, front coil 70, left coil 80, and right coil 90. The inner coil 30 is provided in the same position as in embodiment 1 and has the same conductor pattern. The rear coil 60 is provided behind the inner coil 30. The front coil 70 is provided in front of the inner coil 30. The left coil 80 is provided to the left of the inner coil 30. The right coil 90 is provided to the right of the inner coil 30. The rear coil 60, front coil 70, left coil 80, and right coil 90 are all located outside the substrate 102 relative to the outermost periphery of the inner coil 30. Therefore, the rear coil 60, front coil 70, left coil 80, and right coil 90 are all forms of the "outer coil 40" of the present disclosure. In other words, in embodiment 3, four outer coils 40 are provided.

As shown in FIG. 23, the back surface of the substrate 102 is provided with a connection portion 50 and connection portions 56-58. The connection portion 50 has the same configuration as in embodiment 1. The connection portion 56 is made of a thin-film conductor such as copper foil. The connection portion 56 is electrically connected to the rear coil 60 and the front coil 70, as will be described in detail below. The front-rear connection terminal 600, to which the lead wire 12 is connected, is attached to the connection portion 56 by soldering or the like. The front-rear connection terminal 600 is made of metal and serves as an input terminal for connecting the lead wire 12 to the connection portion 56 and passing electricity from the power supply board 20 to the rear coil 60 and the front coil 70. The configuration of the front-rear connection terminal 600 and the method of connecting the front-rear connection terminal 600 to the lead wire 12 are the same as those of the inner connection terminal 300 in embodiment 1, and therefore will not be described here.

The connection portion 57, details of which will be described later, is electrically connected to the left coil 80 and right coil 90. Furthermore, left and right connection terminals 800, to which the lead wires 12 are connected, are attached to the connection portion 57 by soldering or the like. The left and right connection terminals 800 are made of metal and are input terminals that connect the lead wires 12 to the connection portion 57 and allow electricity to flow from the power supply board 20 to the left coil 80 and right coil 90. The configuration of the left and right connection terminals 800 and the method of connecting the left and right connection terminals 800 to the lead wires 12 are the same as those of the inner connection terminals 300 in embodiment 1, and therefore will not be described here.

The connection portion 58 is made of a thin-film conductor such as copper foil. The connection portion 58 is electrically connected to the inner coil 30, rear coil 60, front coil 70, left coil 80, and right coil 90, as will be described in detail below. A common connection terminal 500, to which the lead wire 12 is connected, is attached to the connection portion 58 by soldering or the like. The common connection terminal 500 is made of metal and connects the lead wire 12 to the connection portion 58, allowing electricity to flow from the inner coil 30, rear coil 60, front coil 70, left coil 80, and right coil 90 to the power supply board 20. The common connection terminal 500 is a terminal shared by the inner coil 30, rear coil 60, front coil 70, left coil 80, and right coil 90. The configuration of the common connection terminal 500 and the method of connecting the common connection terminal 500 to the lead wire 12 are similar to those of the inner connection terminal 300 in embodiment 1, and therefore will not be described here.

Figure 24 is a view of the substrate 102 according to embodiment 3 as viewed from the right. As shown in Figures 23 and 24, the inner connection terminals 300, front and rear connection terminals 600, left and right connection terminals 800, and common connection terminal 500 are arranged side by side along the same side of the substrate 102. Furthermore, when the rear coil 60, front coil 70, left coil 80, and right coil 90 provided on the front surface are projected onto the back surface, the inner connection terminals 300, front and rear connection terminals 600, left and right connection terminals 800, and common connection terminal 500 are all located outside the outermost peripheries of the rear coil 60, front coil 70, left coil 80, and right coil 90.

Now, using Figures 25 to 27, we will provide a detailed description of the inner coil 30, rear coil 60, front coil 70, left coil 80, and right coil 90, as well as the conductor patterns of the connections for connecting these to the respective connection terminals. Figure 25 is a diagram showing the upper layer 111 of the substrate 102 according to embodiment 3. Figure 26 is a diagram showing the middle layer 112 of the substrate 102 according to embodiment 3. Figure 27 is a diagram showing the lower layer 113 of the substrate 102 according to embodiment 3. All of Figures 25 to 27 show the substrate 102 as viewed from above. Below, we will explain the configuration formed on each layer and their electrical connections. Note that the inner coil 30 is the same as in embodiment 1, so its description will be omitted.

First, we will explain the structure formed on each layer, starting from the top layer 111. As shown in Figure 25, the fifth coil 61, which is part of the rear coil 60, is formed on the top layer 111 by winding a thin-film conductor. The fifth coil 61 is wound from via 611 to via 612. Via 611 is one of the vias V1 connecting the top layer 111 and the lower layer 113. Via 612 is one of the vias V2 connecting the top layer 111 and the middle layer 112. Also on the top layer 111, the seventh coil 71, which is part of the front coil 70, is formed by winding a thin-film conductor. The seventh coil 71 is wound from via 711 to via 712. Via 711 is one of the vias V1 connecting the top layer 111 and the lower layer 113. Via 712 is one of the vias V2 connecting the top layer 111 and the middle layer 112. Additionally, the ninth coil 81, which is part of the left coil 80, is formed on the upper layer 111 by winding a thin-film conductor. The ninth coil 81 is wound from via 811 to via 812. Via 811 is one of the vias V1 that connect the upper layer 111 and the lower layer 113. Via 812 is one of the vias V2 that connect the upper layer 111 and the middle layer 112. The eleventh coil 91, which is part of the right coil 90, is formed on the upper layer 111 by winding a thin-film conductor. The eleventh coil 91 is wound from via 911 to via 912. Via 911 is one of the vias V1 that connect the upper layer 111 and the lower layer 113. Via 912 is one of the vias V2 that connect the upper layer 111 and the middle layer 112.

As shown in FIG. 26 , the sixth coil 62, which is part of the rear coil 60, is formed on the middle layer 112 by winding a thin-film conductor. The sixth coil 62 is wound from via 612 to via 613. Via 613 is one of the vias V3 connecting the middle layer 112 and the lower layer 113. The eighth coil 72, which is part of the front coil 70, is also formed on the middle layer 112 by winding a thin-film conductor. The eighth coil 72 is wound from via 712 to via 713. Via 713 is one of the vias V3 connecting the middle layer 112 and the lower layer 113. The tenth coil 82, which is part of the left coil 80, is also formed on the middle layer 112 by winding a thin-film conductor. The tenth coil 82 is wound from via 812 to via 813. Via 813 is one of the vias V3 connecting the middle layer 112 and the lower layer 113. The twelfth coil 92, which is part of the right coil 90, is formed by winding a thin-film conductor on the middle layer 112. The twelfth coil 92 is wound from via 912 to via 913. Via 913 is one of vias V3 that connects the middle layer 112 and the lower layer 113.

As shown in FIG. 27, connection portions 56-58 are formed on the lower layer 113. Connection portion 56 is elongated in the front-to-rear direction and connects the inner connection terminal 300, via 611, and via 711. Connection portion 57 extends from the rear of the substrate 102 to the left, passing through the right and front portions, and connects the left and right connection terminals 800, via 811, and via 911. Connection portion 58 extends from the center of the substrate 102 to the right, passing through the rear, left, and front portions, and connects the common connection terminal 500, via 313, via 613, via 713, via 813, and via 813.

Next, the electrical connections of the components formed on each layer will be explained along the flow of electricity. Note that parentheses indicate which conductor layer each conductor constitutes. The inner coil 30 is the same as in embodiment 1, so explanation will be omitted. For the rear coil 60, power supplied from the power supply board 20 flows in the following order: front and rear connection terminal 600, connection portion 56 (lower layer 113), via 611, fifth coil 61 (upper layer 111), via 612, sixth coil 62 (middle layer 112), via 613, connection portion 58 (lower layer 113), and common connection terminal 500. For the front coil 70, power supplied from the power supply board 20 flows in the following order: front and rear connection terminal 600, connection portion 56 (lower layer 113), via 711, seventh coil 71 (upper layer 111), via 712, eighth coil 72 (middle layer 112), via 713, connection portion 58 (lower layer 113), and common connection terminal 500.

For the left coil 80, power supplied from the power supply board 20 flows in the following order: left and right connection terminal 800, connection portion 57 (lower layer 113), via 811, ninth coil 81 (upper layer 111), via 812, tenth coil 82 (middle layer 112), via 813, connection portion 58 (lower layer 113), and common connection terminal 500. For the right coil 90, power supplied from the power supply board 20 flows in the following order: left and right connection terminal 800, connection portion 57 (lower layer 113), via 911, tenth coil 82 (upper layer 111), via 912, eleventh coil 91 (middle layer 112), via 913, connection portion 58 (lower layer 113), and common connection terminal 500.

Figure 28 is a diagram illustrating the power supply system via the power supply board 20. As shown in Figure 28, the inner coil 30, the rear coil 60 and front coil 70, and the left coil 80 and right coil 90 are individually connected to the power supply board 20 via lead wires 12 and are individually supplied with power. Therefore, the induction cooking device 1 can drive either the inner coil 30, the rear coil 60 and front coil 70, or the left coil 80 and right coil 90, and stop the others. Alternatively, the induction cooking device 1 can drive either the inner coil 30, the rear coil 60 and front coil 70, or the left coil 80 and right coil 90 at high frequency and drive the others at low frequency. In this way, the induction cooking device 1 can independently drive the inner coil 30, the rear coil 60 and front coil 70, and the left coil 80 and right coil 90.

As described above, according to the induction cooking device 1 of embodiment 3, similar to embodiment 1, the inner coil 30, the rear coil 60 and front coil 70, and the left coil 80 and right coil 90 are independently connected to the power supply board 20. Therefore, the induction cooking device 1 can independently drive the inner coil 30, the rear coil 60 and front coil 70, and the left coil 80 and right coil 90, thereby preventing uneven heating.

Furthermore, the induction heating cooker 1 of embodiment 3 has a rear coil 60, a front coil 70, a left coil 80, and a right coil 90, so the position at which the heated object is heated can be finely adjusted. Therefore, uneven heating can be further prevented.

Embodiment 4.
The induction heating cooker 1 of the fourth embodiment differs from the first embodiment in that a slit 120 and a positioning hole 130 are formed in the substrate 102. Below, the differences from the first embodiment will be described, and a description of the commonalities with the first embodiment will be omitted.

Figure 29 is a top view of the substrate 102 according to embodiment 4. Figure 30 is a bottom view of the substrate 102 according to embodiment 4. As shown in Figures 29 and 30, the substrate 102 has multiple slits 120 and multiple positioning holes 130 formed therein. The slits 120 are formed between the inner coil 30 and the outer coil 40 and penetrate the substrate 102 in the vertical direction. The inner coil 30 is surrounded by the multiple slits 120. The slits 120 surround almost the entire circumference of the inner coil 30, but are not formed in the areas where the inner coil 30 and outer coil 40 are located or where the ferrite 103 is disposed. The positioning holes 130 are formed outside the outermost periphery of the outer coil 40 and penetrate the substrate 102 in the vertical direction. The positioning holes 130 are shaped to generally fit over the protrusions 150 of the jig 106, which will be described later.

Figures 31 and 32 are cross-sectional views showing the substrate 102 and ferrite 103 according to embodiment 4. Figure 31 shows a cross-section of the substrate 102 and ferrite 103 of Figure 30 taken along the A-A cross-section. In other words, Figure 31 is a cross-section including the slit 120. Figure 32 shows a cross-section of the substrate 102 and ferrite 103 of Figure 30 taken along the B-B cross-section. In other words, Figure 32 is a cross-section including the positioning hole 130. As shown in Figures 31 and 32, the ferrite 103 is adhered to the substrate 102 with silicone 140. As will be described in detail later, the adhesion position of the ferrite 103 relative to the substrate 102 is determined by inserting a jig 106 into the ends of the slits 120 located on the sides of the ferrite 103 and into all of the positioning holes 130. Therefore, as shown in Figure 31, the ends of the slits 120 are located on both sides of each ferrite 103. Additionally, as shown in Figure 32, positioning holes 130 are formed on both sides of each ferrite piece 103.

The procedure for adhering the ferrite 103 to the substrate 102 will now be described using Figures 33 to 35. Figure 33 is a diagram showing the substrate 102 and jig 106 according to embodiment 4. As shown in Figure 33, the dimensions of the bottom surface of the jig 106 are approximately the same as the surface of the substrate 102, and the edges are raised on all four sides from the bottom surface. The jig 106 has multiple protrusions 150. The protrusions 150 are provided corresponding to the positions where the ferrite 103 will be adhered. Specifically, after the substrate 102 is fitted into the jig 106, the adhesion position of the ferrite 103 is determined so that both sides are sandwiched at two different positions in the radial direction of the substrate 102. For this reason, eight pairs of two protrusions 150 corresponding to the eight ferrite pieces 103 are arranged in a ring shape on the jig 106. In Figure 33, one of the pairs is indicated by dashed line P1. Additionally, eight more sets of protrusions 150 are provided on the jig 106 outside of these eight sets of protrusions 150. In Figure 33, the set provided outside P1 is indicated by dashed line P2.

34 and 35 are diagrams showing the substrate 102 set in the jig 106 according to embodiment 4. FIG. 34 shows a cross section similar to FIG. 31 with the jig 106 inserted into the substrate 102. FIG. 35 shows a cross section similar to FIG. 32 with the jig 106 inserted into the substrate 102. In the first bonding step, the substrate 102 is set in the jig 106 so that the surface of the substrate 102 is in contact with the bottom surface of the jig 106. At this time, as shown in FIG. 34, multiple protrusions 150 are inserted into the opposing slits 120. The protrusions 150 inserted into the slits 120 are positioned at the ends of the slits 120. Furthermore, as shown in FIG. 35, multiple protrusions 150 are inserted into the opposing positioning holes 130. In the second bonding step, silicone 140 is applied to the positions of the substrate 102 where the ferrite 103 is to be bonded. In the third bonding step, the ferrite 103 is placed on the silicone 140. This causes the ferrite 103 to adhere to the rear surface of the substrate 102. Because the slits 120 and positioning holes 130 are formed at different radial positions on the substrate 102, the multiple protrusions 150 inserted into the slits 120 and positioning holes 130 prevent the ferrite 103 from shifting its adhesion position.

As described above, according to the induction heating cooker 1 of embodiment 4, the inner coil 30 and the outer coil 40 are independently connected to the power supply board 20, just as in embodiment 1. Therefore, the induction heating cooker 1 can independently drive the inner coil 30 and the outer coil 40, thereby preventing uneven heating.

Furthermore, according to embodiment 4, slits 120 are formed in the substrate 102. This allows the air blown by the fan from the back surface of the substrate 102 to escape more easily, improving the cooling efficiency of the surface of the substrate 102.

Furthermore, according to embodiment 4, slits 120 and positioning holes 130 are formed in the substrate 102. By inserting the jig 106 into the slits 120 and positioning holes 130, the mounting position of the ferrite 103 can be determined.

The various aspects of this disclosure are summarized below as appendices.

(Appendix 1)
an insulating multilayer substrate;
an inner coil formed by winding a conductor across two layers of the substrate;
an outer coil formed by winding a conductor across two layers of the substrate and positioned outside the outermost periphery of the inner coil;
an electric power supply board to which the inner coil and the outer coil are independently connected;
(Appendix 2)
The inner coil is
a first coil formed by winding a conductor on a first layer of the substrate;
a second coil electrically connected to the first coil and formed by winding a conductor on a second layer of the substrate,
The outer coil is
a third coil formed by winding a conductor around the first layer and positioned outside the outer periphery of the first coil;
and a fourth coil formed by winding a conductor around the second layer, the fourth coil being electrically connected to the third coil and formed outside the outer periphery of the third coil.
(Appendix 3)
The substrate is
a first substrate;
a second substrate provided below the first substrate,
the first layer is a layer formed on an upper surface of the first substrate,
The induction heating cooker according to claim 2, wherein the second layer is a layer sandwiched between the first substrate and the second substrate.
(Appendix 4)
The substrate is
a first substrate;
a second substrate provided below the first substrate,
the first layer is a layer formed on an upper surface of the first substrate,
The induction heating cooker according to claim 2, wherein the second layer is a layer formed on a lower surface of the second substrate.
(Appendix 5)
5. The induction heating cooker according to any one of appendices 1 to 4, wherein an inner connection terminal connecting the inner coil and the power supply board is arranged outside an outer periphery of the outer coil.
(Appendix 6)
The induction heating cooker according to any one of appendices 1 to 5, wherein an outer connection terminal connecting the outer coil and the power supply board is arranged outside an outer periphery of the outer coil.
(Appendix 7)
The outer coil includes four of the outer coils,
The induction heating cooker according to any one of appendices 1 to 6, wherein each of the outer coils is arranged one on each of the four sides of the inner coil.
(Appendix 8)
The substrate is
8. The induction heating cooker according to any one of claims 1 to 7, further comprising a slit formed between the inner coil and the outer coil.
(Appendix 9)
Further, the substrate is provided with ferrite that guides magnetic flux toward the object to be heated,
The substrate is
a positioning hole formed outside the outer periphery of the outer coil,
The induction heating cooker according to claim 8, wherein an attachment position of the ferrite on the substrate is determined by a jig inserted into the slit and the positioning hole.

1 induction heating cooker, 2 main body case, 3 top plate, 4 heating area, 5 grill cooker, 5a grill chamber, 6 grill door, 7 operation display panel, 8 air intake, 9 exhaust port, 10 induction heating unit, 11 spacer, 12 lead wire, 12a terminal portion, 12b terminal screw, 20 power supply board, 30, 30A inner coil, 31, 31A, first coil, 32, 32A second coil, 40, 40A outer coil, 41, 41A third coil, 42, 42A fourth coil, 50 to 52, 53, 53a, 53b, 54, 55, 56, 57, 58 connection portion, 60 rear coil, 61 fifth coil, 62 sixth coil, 70 front coil, 71 seventh coil, 72 eighth coil, 80 left coil, 81 ninth coil, 82 10th coil, 90 right coil, 91 11th coil, 92 12th coil, 101 magnetic shielding member, 102 substrate, 102a first substrate, 102b second substrate, 103 ferrite, 104 holding member, 105 fixing screw, 106 jig, 111 upper layer, 112 middle layer, 113 lower layer, 120 slit, 130 positioning hole, 140 silicone, 150 protrusion, 300 inner connection terminal, 300a screw hole, 311 to 313, 321 to 325 via, 400 outer connection terminal, 411 to 413, 421, 422 via, 500 common connection terminal, 600 front and rear connection terminal, 611 to 613 via, 711 to 713 via, 800 left and right connection terminal, 811 to 813 Vias, 911-913 vias, V1-V3 vias.

Claims (6)

an insulating multilayer substrate;
an inner coil formed by winding a conductor across two layers of the substrate;
an outer coil formed by winding a conductor across two layers of the substrate and positioned outside the outermost periphery of the inner coil;
a power supply board to which the inner coil and the outer coil are independently connected ,
The inner coil is
a first coil formed by winding a conductor on a first layer of the substrate;
a second coil electrically connected to the first coil and formed by winding a conductor on a second layer of the substrate,
The outer coil is
a third coil formed by winding a conductor around the first layer and positioned outside the outer periphery of the first coil;
a fourth coil formed by winding a conductor around the second layer, the fourth coil being electrically connected to the third coil and formed outside an outer periphery of the third coil,
The substrate is
a first substrate;
a second substrate provided below the first substrate,
The second substrate is located at the bottom of the substrate,
the first layer is a layer formed on an upper surface of the first substrate,
The second layer is a layer formed on the lower surface of the second substrate.
Induction heating cooker. The induction heating cooker according to claim 1 , wherein an inner connection terminal that connects the inner coil to the power supply board is disposed outside an outer periphery of the outer coil. The induction heating cooker according to claim 1 or 2 , wherein an outer connection terminal that connects the outer coil to the power supply board is disposed outside an outer periphery of the outer coil. having four of the outer coils,
The induction heating cooker according to claim 1 or 2 , wherein the outer coils are arranged one on each of the four sides of the inner coil. The substrate is
The induction heating cooker according to claim 1 or 2 , further comprising a slit formed between the inner coil and the outer coil. Further, the substrate is provided with ferrite that guides magnetic flux toward the object to be heated,
The substrate is
a positioning hole formed outside the outer periphery of the outer coil,
The end of the slit and the end of the positioning hole are positioned on the same straight line.
The induction heating cooker according to claim 5 .