JP7660601B2 - Induction Cooker - Google Patents

Description

The present invention relates to an induction heating cooker.

For example, Patent Document 1 describes an induction heating cooker that includes "a left board mounted with electronic components that supply power to the left heating coil and the middle heating coil, and a right board mounted with electronic components that supply power to the right heating coil."

JP 2017-68940 A

In the technology described in Patent Document 1, three or more high heat generating elements such as IGBTs (Insulated Gate Bipolar Transistors) or diode bridges are mounted in a row on each of the left and right boards. As a result, the temperature of the cooling air hitting the high heat generating elements increases toward the downstream side (downwind side) of the air flow. There is room to further improve the cooling performance of electronic components that contain high heat generating elements, but such technology is not described in Patent Document 1.

Therefore, the objective of the present invention is to provide an induction heating cooker with high cooling performance for electronic components.

In order to solve the above-mentioned problems, an induction heating cooker according to the present invention includes a board cover installed so as to cover a first board installed in a main body, a first heating coil and a second heating coil installed on the upper side of the board cover, and a fan device that sends air between the first board and the board cover in a vertical direction, and the first board includes a first heat sink arranged on a first inverter element of a first inverter circuit connected to the first heating coil, a second heat sink arranged on a second inverter element of a second inverter circuit connected to the second heating coil, and a diode heat sink arranged on a diode bridge connected to the DC sides of the first inverter circuit and the second inverter circuit. a heat sink is mounted on the first heat sink, the second heat sink, and the diode heat sink are arranged on the side where air blows out from the fan device, and with the surface on which a front panel is provided, the left-right distance between the first heat sink and the diode heat sink and the left-right distance between the second heat sink and the diode heat sink are longer than the left-right distance between the first heat sink and the second heat sink, and with the surface on which the front panel is provided being the front, the air blown out from the fan device flows in the front-to-rear direction via each of the first heat sink, the second heat sink, and the diode heat sink .

The present invention provides an induction heating cooker with excellent cooling performance for electronic components.

1 is a perspective view of an induction heating cooker according to a first embodiment; FIG. 2 is a plan view of the induction heating cooker according to the first embodiment with a top plate removed. FIG. 2 is an exploded perspective view of the induction heating cooker according to the first embodiment. FIG. 2 is an exploded perspective view of a fan device included in the induction heating cooker according to the first embodiment. FIG. 2 is a longitudinal sectional view of the induction heating cooker according to the first embodiment, taken along line V-V in FIG. 1 . 6 is a longitudinal sectional view of the induction heating cooker according to the first embodiment taken along line VI-VI in FIG. 1. 1 is a plan view including a fan device, left and right substrates, and a middle substrate provided in an induction heating cooker according to a first embodiment. FIG. FIG. 2 is a circuit diagram of the induction heating cooker according to the first embodiment. 9 is a longitudinal sectional view of the left and right substrates of the induction heating cooker according to the first embodiment taken along line IX-IX in FIG. 7 . FIG. 4 is a bottom view of the board cover included in the induction heating cooker according to the first embodiment. FIG. 11 is a plan view of the induction heating cooker according to the second embodiment with the top plate removed. FIG. 11 is a plan view including left and right boards and a fan device provided in the induction heating cooker according to the second embodiment.

The following describes, as an example, an induction heating cooker 100 (see FIG. 1) configured as a built-in induction heating (IH) cooking heater equipped with a grill chamber 4 (see FIG. 1).

First Embodiment
FIG. 1 is a perspective view of an induction heating cooker 100 according to the first embodiment.
As shown in FIG. 1, the surface of the induction heating cooker 100 on which the front panel 5 is provided is defined as the front (front face), and front-rear, left-right, and top-bottom are defined based on this.
The induction cooker 100 shown in Fig. 1 is a device that generates eddy currents in the bottom of a metal pot (not shown) to heat the pot itself with Joule heat generated by the eddy currents. The eddy currents are generated by passing a predetermined high-frequency current through the right heating coil 6 (see Fig. 2), the left heating coil 7 (see Fig. 2), and the middle heating coil 8 (see Fig. 2), thereby changing the magnetic flux over time.

As shown in FIG. 1, the induction cooking device 100 includes a main body 1, a top plate 2, an exhaust cover 3, a grill chamber 4, and a front panel 5. The main body 1 is a housing that forms the outer shell of the induction cooking device 100, and is box-shaped (concave) with an open top (see also FIG. 3).

The top plate 2 comprises a plate glass 2a on which a pot (not shown) to be cooked is placed, and a frame 2b that holds the four sides of the plate glass 2a, and is installed to cover the upper opening of the main body 1. The top plate 2 further comprises a three-port pot placement section 2c corresponding to the respective installation positions of the right heating coil 6 (see FIG. 2), left heating coil 7 (see FIG. 2), and middle heating coil 8 (see FIG. 2), and an operation panel 2d used to adjust the heating of the pot to be cooked. Note that while FIG. 1 shows an example in which the operation panel 2d is provided on the top plate 2, a part or all of the operation panel 2d may be provided on the front panel 5.

The exhaust cover 3 is a thin metal plate provided at the rear end of the top plate 2. The exhaust cover 3 has a number of holes 3h as exhaust ports for exhausting the air blown out from the fan unit 9 (see FIG. 2). The exhaust cover 3 is removable so that it can be washed if it becomes dirty.

The grill chamber 4 (also called a roaster or oven) heats food to be cooked using an upper heater 4b (see FIG. 6) and a lower heater 4c (see FIG. 6), which will be described later. In the example of FIG. 1, the grill chamber 4 is provided on the left front side of the main body 1 and can slide forward and backward.

The front panel 5 is provided on the main body 1 so as to be adjacent to the front of the grill chamber 4 in the left-right direction. A plug P is connected to the main body 1 via a wiring cord C.

FIG. 2 is a plan view of the induction heating cooker 100 with the top plate removed.
As shown in FIG. 2 , the induction heating cooker 100 includes a right heating coil 6 (first heating coil), a left heating coil 7 (second heating coil), a middle heating coil 8 (third heating coil), and a fan device 9.

The right heating coil 6, left heating coil 7, and middle heating coil 8 are each a coil through which a predetermined high-frequency current flows, and are provided on the underside of the top plate 2 (see FIG. 1). In the example of FIG. 2, the right heating coil 6 is provided in the right region of the main body 1 in a plan view, and the left heating coil 7 is provided in the left region of the main body 1. Also, the middle heating coil 8 is provided at the back center of the main body 1 in a plan view.

The fan device 9 is a device that blows out cooling air to dissipate heat from the right heating coil 6, the left heating coil 7, and the middle heating coil 8, as well as the electronic components mounted on the left and right boards 15 (see FIG. 3) and the middle board 16 (see FIG. 3), which will be described later. The board cover 12, the left and right boards 15, and the middle board 16 shown in FIG. 2 will be described later.

FIG. 3 is an exploded perspective view of the induction heating cooker 100. As shown in FIG.
In addition to the above-mentioned components, the induction heating cooker 100 further comprises a coil base 10, a temperature sensor 11, a board cover 12, board stands 13 and 14, left and right boards 15, and a middle board 16, all of which are shown in FIG.

The coil base 10 is a member on which the right heating coil 6, left heating coil 7, and middle heating coil 8 are placed, and is supported at three points by supports 20 (see FIG. 5) such as springs. An upward biasing force is applied to the coil base 10 from the supports 20, pressing the right heating coil 6, etc. against the underside (rear surface) of the top plate 2, and maintaining a predetermined distance between the cooking pot (not shown) and the right heating coil 6, etc.

The temperature sensors 11 are sensors that detect the temperature of the bottom of a cooking pot (not shown), and are provided near the center of each of the right heating coil 6, the left heating coil 7, and the middle heating coil 8.
The board cover 12 vertically separates the left and right boards 15 and the middle board 16 from the heating coils (the right heating coil 6, the left heating coil 7, and the middle heating coil 8). The board cover 12 also has the function of forming an air passage that guides the cooling air blown out from the fan device 9 in a predetermined direction.

The board cover 12 is installed so as to cover the left and right boards 15 (first board) and at least a part of the middle board 16 (second board). The right heating coil 6, the left heating coil 7, and the middle heating coil 8 are installed on the upper side of the board cover 12. The upper casing 9d of the fan unit 9 is provided substantially integrally with the board cover 12.

The substrate stand 13 is an insulating member made of resin on which the left and right substrates 15 are placed, and has a rectangular shape corresponding to the left and right substrates 15 in a plan view. The other substrate stand 14 is an insulating member on which the middle substrate 16 is placed, and has a rectangular shape corresponding to the middle substrate 16 in a plan view. These substrate stands 13, 14 are fixed to each other so that their respective plate surfaces are approximately flush and so that they are adjacent to each other at a predetermined distance in the front-to-back direction. Then, a substrate cover 12 is installed so as to cover these substrate stands 13, 14 from above.

As described above, the main body 1 is box-shaped (concave) with an open top. Specifically, the main body 1 is configured to include a partition plate 1a (the bottom plate of the main body 1) that is rectangular in plan view, and a side plate 1b that extends upward from the edge of the partition plate 1a. The base plates 13 and 14 are fixed to the partition plate 1a of the main body 1. The partition plate 1a is provided with an intake opening 1h for directing air from the outside to the intake port 91h (see FIG. 5) of the fan device 9. The main body 1 is also provided with a display unit 17 for displaying the state of the induction heating cooker 100 in a predetermined manner.

The left and right boards 15 (first boards) are printed circuit boards on which predetermined electronic components are mounted, and are installed on the main body 1. Such electronic components include right inverter elements S1, S2 (see FIG. 7) connected to the right heating coil 6, left inverter elements S3, S4 (see FIG. 7) connected to the left heating coil 7, as well as a diode bridge 21 (see FIG. 7), integrated circuits, capacitors, resistors, etc.

The middle board 16 (second board) is a printed circuit board on which certain electronic components are mounted, and is installed in the main body 1. Such electronic components include middle inverter elements S5, S6 (see FIG. 7) connected to the middle heating coil 8, as well as capacitors and resistors. The left and right boards 15 and middle board 16 are electrically connected via power lines and communication lines.

The water receiving section 18 shown in FIG. 3 receives droplets that drip through the holes 3h (see FIG. 1) in the exhaust cover 3, and is provided below the exhaust cover 3 and behind the fan unit 9. The water receiving section 18 is also provided with a lattice-shaped partition 18a to separate it from the fan unit 9. Providing this partition 18a prevents droplets from entering the fan unit 9.

FIG. 4 is an exploded perspective view of the fan device 9 provided in the induction heating cooker.
The fan device 9 shown in Fig. 4 is a centrifugal fan including a motor 9a, an impeller 9b, and casings 9c and 9d. The motor 9a is the driving source of the fan device 9, and includes a stator (not shown) and a rotor (not shown), as well as a rotating shaft 91a that rotates integrally with the rotor. The impeller 9b is an impeller that sends out air by rotating in response to the driving of the motor 9a. The casings 9c and 9d house the motor 9a and the impeller 9b.

As shown in FIG. 4, the lower casing 9c is configured by integrally molding a bottom 91c, a side 92c, a pair of tongues 93c, 94c, and a branch 95c. An intake port 91h is provided near the center of the impeller 9b in the bottom 91c of the casing 9c. The side 92c of the casing 9c extends upward from the edge of the bottom 91c and has a C-shape in plan view (in FIG. 4, the C-shape is reversed).

The pair of tongues 93c, 94c are formed so as to bend outward from one end and the other end of the side portion 92c in a plan view. The branch portion 95c has the function of dividing the air discharged in response to the rotation of the impeller 9b into two directions. As shown in FIG. 4, the branch portion 95c has an inverted V-shape in a plan view, and is provided at a predetermined position between the pair of tongues 93c, 94c.

The impeller 9b connected to the rotating shaft 91a of the motor 9a is then installed in the casing 9c, and another casing 9d is then fixed to cover the casing 9c from above. In this state, the impeller 9b is rotatably supported by the rotating shaft 91a of the motor 9a so as not to come into contact with the casings 9c and 9d.

The front air outlet 92h (one of the air outlets) and the left air outlet 93h (the other air outlet) shown in FIG. 4 are openings through which air is blown out from the fan device 9, and are provided between the left and right boards 15 (first board: see FIG. 3) and the board cover 12 (see FIG. 3) in the vertical direction.

In addition, the left air outlet 93h is configured to include a part of the bottom 91c of the casing 9c, one of the tongue portions 93c, and the branch portion 95c (the portion facing the tongue portion 93c), as well as a part of the substrate cover 12 (see Figure 3).
The front air outlet 92h is configured to include a part of the bottom 91c of the casing 9c, the other tongue 94c, and the branching portion 95c (the portion facing the tongue 94c), as well as a part of the board cover 12 (see FIG. 3). When the impeller 9b rotates as the motor 9a is driven, air introduced into the casings 9c and 9d through the intake port 91h is split and blown out in two directions, the front air outlet 92h and the left air outlet 93h.

It is desirable that the fan device 9 has pressure-air volume characteristics with sufficient margin against the ventilation resistance (e.g., 100 [Pa] to 200 [Pa]) inside the main body 1 (see FIG. 3). This makes it possible to obtain the air volume required for cooling (e.g., 1.0 to 1.5 [m ³ /min]) even at low rotation speeds, thereby efficiently cooling the heating coils as well as the electronic components on the left and right boards 15 (see FIG. 3) and middle board 16 (see FIG. 3), and also reducing noise during induction heating.

FIG. 5 is a vertical cross-sectional view of the induction heating cooker 100 taken along line VV in FIG.
The white arrows in Fig. 5 indicate the flow of air. As shown in Fig. 5, an intake opening 1h for taking air from the outside into the main body 1 is provided on the rear surface of the main body 1. Also, a duct 19 is provided in the space at the rear of the main body 1. The duct 19 guides the air flowing in through the intake opening 1h of the main body 1 to the intake port 91h of the fan device 9.

When the fan unit 9 is driven, the air that has passed through the intake opening 1h and the duct 19 in sequence is led to the fan unit 9 through the intake port 91h. The air pressurized by the fan unit 9 is then split into two directions through the front outlet 92h (see FIG. 4) and the left outlet 93h (see FIG. 4). In FIG. 5, the flow of air discharged through the front outlet 92h, one of the two directions, is indicated by a hollow arrow.

The air blown out through the front outlet 92h of the fan unit 9 flows generally forward through the space F1 between the left and right boards 15 and the board cover 12. This promotes heat dissipation from each electronic component E mounted on the left and right boards 15. The air that has flowed through the space F1 between the left and right boards 15 and the board cover 12 is then guided through the upper outlet 12h of the board cover 12 to the space F2 between the board cover 12 and the top plate 2. As the air flows through this space F2, the right heating coil 6 and the like are appropriately cooled. The air that has flowed through the space F2 is then exhausted to the outside through holes 3h provided in the exhaust cover 3.

FIG. 6 is a vertical cross-sectional view of the induction heating cooker 100 taken along line VI-VI in FIG.
As shown in Fig. 6, the grill chamber 4 is provided with a heating chamber 4k as a space partitioned by a partition plate 4a. The heating chamber 4k is provided with an upper heater 4b and a lower heater 4c as heat sources, a grill net 4d on which fish or the like is placed, and a tray 4e arranged below the grill net 4d. The tray 4e is slidable in the front-rear direction together with the grill net 4d.

The heat source for heating the food in the heating chamber 4k is not limited to an electric heater, but may be microwaves, steam, or a combination of these. Also, a temperature regulator (not shown) may be used to adjust the temperature inside the grill chamber 4 while performing oven heating as desired. The ferrite 3f shown in FIG. 6 is a high magnetic permeability material for suppressing electromagnetic effects on the left and right boards 15, and is installed below the middle heating coil 8, etc.

The air blown out through the left air outlet 93h of the fan unit 9 flows generally leftward through the space F1 between the left and right boards 15 and the board cover 12, cooling each electronic component E mounted on the left and right boards 15. The air that has flowed through the space F1 is then guided through the upper air outlet 12h (see FIG. 5) into the space F2 between the top plate 2 and the board cover 12.

FIG. 7 is a plan view including the fan device 9, the left and right substrates 15, and the middle substrate 16 provided in the induction heating cooker 100. As shown in FIG.
In Fig. 7, ribs Ra, Rb, Rc, and Rd and board cover partitions Rs and Rt that are integrally provided on the back side of the board cover 12 (see also Fig. 10) are indicated by dashed lines. Also, in Fig. 7, air flows are indicated by outline arrows.

As shown in FIG. 7, left and right boards 15 are disposed in front of the fan device 9, and air blown out through the front air outlet 92h of the fan device 9 is guided to the left and right boards 15. In addition, a middle board 16 is provided on the left side of the fan device 9, and air blown out through the left air outlet 93h of the fan device 9 is guided to the middle board 16.

The middle board 16 is disposed behind the left and right boards 15 in the front-rear direction, and is electrically connected to the left and right boards 15 via a connection 29. The connection 29 consists of a fixing portion 29a that directly fixes the left and right boards 15 and the middle board 16 to the board base, and a hook 29b through which the power line passes. The board surface (top surface) of the middle board 16 is substantially flush with the board surfaces (top surfaces) of the left and right boards 15. As shown in FIG. 7, in addition to the diode bridge 21, a pair of right inverter elements S1, S2 and a pair of left inverter elements S3, S4 are mounted on the left and right boards 15. Each of these electronic components will be described with reference to FIG. 8.

FIG. 8 is a circuit diagram of the induction heating cooker 100.
The induction heating cooker 100 includes, as electronic components mounted on the left and right substrates 15 (see FIG. 7), a diode bridge 21, a smoothing capacitor 22, a right inverter circuit 23 (first inverter circuit), a left inverter circuit 24 (second inverter circuit), and resonant capacitors 26 and 27. The induction heating cooker 100 also includes, as electronic components mounted on the middle substrate 16 (see FIG. 7), a middle inverter circuit 25 (third inverter circuit), a middle heating coil 8 (third heating coil), and a resonant capacitor 28.

The diode bridge 21 is a circuit that full-wave rectifies the AC voltage applied from the AC power source Q and converts it into a DC voltage (pulsating current). In the example of FIG. 8, the diode bridge 21 is configured with four diodes D1 to D4 connected in a bridge shape. The smoothing capacitor 22 is a capacitor that smoothes the voltage applied from the diode bridge 21 (pulsating DC voltage).

The right inverter circuit 23 is a power conversion circuit that converts the DC voltage applied from the smoothing capacitor 22 via the wiring 30a, 30b into a predetermined high-frequency voltage, and is connected to the right heating coil 6. As shown in FIG. 8, the right inverter circuit 23 includes a pair of right inverter elements S1, S2 (first inverter elements). For example, IGBTs are used as the right inverter elements S1, S2 (the same applies to the left inverter elements S3, S4 and the middle inverter elements S5, S6).

In the example of FIG. 8, the emitter of one right inverter element S1 is connected to the collector of the other right inverter element S2, and the intermediate connection point is connected to one end of the right heating coil 6. In addition, the collector of one right inverter element S1 is connected to the positive electrode of the smoothing capacitor 22, and the emitter of the other right inverter element S2 is connected to the negative electrode of the smoothing capacitor 22. A freewheel diode D is connected in anti-parallel to each of the pair of right inverter elements S1 and S2.

The pair of resonant capacitors 26, 26 are connected in series with each other, and their intermediate connection point is connected to the other end of the right heating coil 6. The pair of right inverter elements S1, S2 are turned on and off in a predetermined manner, allowing a high-frequency current to flow through the right heating coil 6.

The left inverter circuit 24 is a power conversion circuit that converts the DC voltage applied from the smoothing capacitor 22 through the wiring 30c, 30d into a predetermined high-frequency voltage, and is connected to the left heating coil 7. The left inverter circuit 24 is connected to the positive electrode of the smoothing capacitor 22 through the wiring 30c and the wiring 30a (part), and is connected to the negative electrode of the smoothing capacitor 22 through the wiring 30d and the wiring 30b (part). As shown in FIG. 8, the left inverter circuit 24 includes a pair of left inverter elements S3, S4 (second inverter elements), the intermediate connection point of which is connected to the left heating coil 7. In addition, a pair of resonant capacitors 27, 27 are connected in series with each other, and the intermediate connection point of which is connected to the other end of the left heating coil 7.

The middle inverter circuit 25 is a power conversion circuit that converts the DC voltage applied from the smoothing capacitor 22 through the wiring 30e, 30f to a predetermined high-frequency voltage, and is connected to the middle heating coil 8. The middle inverter circuit 25 is connected to the positive electrode of the smoothing capacitor 22 through the wiring 30e and the wiring 30a (part), and is connected to the negative electrode of the smoothing capacitor 22 through the wiring 30f and the wiring 30b (part). As shown in FIG. 8, the middle inverter circuit 25 includes a pair of middle inverter elements S5, S6 (third inverter elements), the intermediate connection point of which is connected to the middle heating coil 8. In addition, a pair of resonant capacitors 28, 28 are connected to each other in series, and the intermediate connection point of which is connected to the other end of the middle heating coil 8.

In the first embodiment, as shown in FIG. 8, one diode bridge 21 is shared (commonized) by the right inverter circuit 23, the left inverter circuit 24, and the middle inverter circuit 25, and this diode bridge 21 is mounted on one left and right board 15 (see FIG. 7). In other words, the diode bridge 21 is commonly connected to the DC side of each of the right inverter circuit 23, the left inverter circuit 24, and the middle inverter circuit 25. This reduces the mounting area of the diode bridge 21, and ultimately makes it possible to make the left and right boards 15 (see FIG. 7) more compact. Note that the circuit diagram in FIG. 8 is an example, and the circuit configuration of the induction heating cooker 100 is not limited to this.

FIG. 9 is a vertical cross-sectional view of the left and right substrates 15 and the like of the induction heating cooker 100 taken along line IX-IX in FIG.
As shown in Fig. 9, the left and right substrates 15 are provided with a heat sink H1 (first heat sink) as a metal member on which the right inverter element S1 is installed. The heat sink H1 includes a plate-shaped base Ha1 on which the right inverter element S1 is installed, and a plurality of fins Hb1 extending vertically from the base Ha1. In the example of Fig. 9, the heat sink H1 is installed so that the base Ha1 is vertical to the substrate surfaces of the left and right substrates 15, and the plurality of fins Hb1 extend to the left side from the base Ha1. The same is true for the heat sink H2 (see Fig. 7) on which the other right inverter element S2 (see Fig. 7) is installed.

The left and right substrates 15 are also provided with a heat sink H3 (second heat sink) as a metal member on which the left inverter element S3 is mounted. The heat sink H3 includes a plate-shaped base Ha3 on which the left inverter element S3 is mounted, and a plurality of fins Hb3 extending perpendicularly from the base Ha3. In the example of FIG. 9, the heat sink H3 is mounted so that the base Ha3 is perpendicular to the substrate surfaces of the left and right substrates 15, and the plurality of fins Hb3 extend to the right from the base Ha3. The same is true for the heat sink H4 (see FIG. 7) on which the other left inverter element S4 (see FIG. 7) is mounted.

In the example of FIG. 9, the tips of the fins Hb1 of the heat sink H1 and the tips of the fins Hb3 of the heat sink H3 face each other in the left-right direction with a certain gap between them. A board cover partition Rs (see also FIG. 7) extending in the front-rear direction is provided in this gap. The board cover partition Rs is a member that separates the areas of the heat sinks H1 and H3 to form an air path for the cooling air, and extends downward from the back surface of the board cover 12.

As shown in FIG. 7, heat sinks H1, H2 (first heat sinks) are individually installed on the pair of right inverter elements S1, S2 (first inverter elements). The pair of heat sinks H1, H2 are arranged in a row along the flow direction of the cooling air (front-to-back direction in FIG. 7). In the example of FIG. 7, of the pair of heat sinks H1, H2, the heat sink H2 on the downstream side of the cooling air has a longer length extending in the flow direction of the cooling air than the heat sink H1 on the upstream side of the cooling air. This improves the cooling performance of the heat sink H2 on the leeward side relative to the heat sink H1 on the windward side.

For example, the length L1 of the heat sink H1 on the windward side in the front-to-rear direction may be 25 mm, and the length L2 of the heat sink H2 on the leeward side in the front-to-rear direction may be 35 mm. By defining the relationship in the length of the heat sinks H1 and H2 in the front-to-rear direction in this way, even if the temperature of the cooling air rises due to heat dissipation from one of the right inverter elements S1, the other right inverter element S2 is also adequately cooled by heat dissipation via the heat sink H2 on the leeward side.

Similarly, heat sinks H3 and H4 (second heat sinks) are installed separately on the pair of left inverter elements S3 and S4 (second inverter elements), respectively. The pair of heat sinks H3 and H4 are arranged in a row along the flow direction of the cooling air. Of the pair of heat sinks H3 and H4, the heat sink H4 on the downstream side of the cooling air has a longer length extending in the flow direction of the cooling air than the heat sink H3 on the upstream side of the cooling air. This improves the cooling performance of the heat sink H4 on the leeward side relative to the heat sink H3 on the windward side.

The left and right substrates 15 are also provided with a heat sink HD (heat sink for diodes) as a metal member on which the diode bridge 21 is mounted. As shown in FIG. 9, the heat sink HD has a plate-shaped base HDa on which the diode bridge 21 is mounted, and a number of fins HDb extending vertically from the base HDa. In the example of FIG. 9, the heat sink HD is mounted so that the base HDa is perpendicular to the substrate surfaces of the left and right substrates 15, and the multiple fins HDb extend horizontally from the base HDa.

As shown in FIG. 7, the horizontal distance between the heat sinks H1 and HD (the first heat sink and the diode heat sink) is preferably longer than the horizontal distance between the heat sinks H1 and H3 (the first heat sink and the second heat sink). Furthermore, the horizontal distance between the heat sinks H3 and HD (the second heat sink and the diode heat sink) is preferably longer than the horizontal distance between the heat sinks H1 and H3 (the first heat sink and the second heat sink). With this configuration, heat transfer from one side to the other of the right inverter elements S1 and S2 and the diode bridge 21 is suppressed. Heat transfer from one side to the other of the left inverter elements S3 and S4 and the diode bridge 21 is also suppressed. Therefore, the right inverter elements S1 and S2, the left inverter elements S3 and S4, and the diode bridge 21 are efficiently cooled by heat exchange with the cooling air.

In the example of FIG. 9, the number of fins Hb1, Hb3 of the heat sinks H1, H3 (12) is greater than the number of fins HDb of the heat sink HD (10). This reduces the mounting area of the heat sinks H1, H3 and also reduces the pressure loss when the cooling air flows through the heat sinks H1, H3, improving the cooling efficiency (the same applies to the heat sinks H2, H4). The vertical length relationship of the heat sinks H1 to H4, HD can be changed as appropriate.

Returning to FIG. 7 again, the explanation will be continued.
As shown in Fig. 7, when paying attention to the installation positions of the heat sinks H1 to H4, HD provided on the left and right boards 15, they are arranged as follows. That is, in the direction (left and right direction) perpendicular to the flow direction (front and back direction) of the cooling air flowing through the heat sinks H1, H2 (first heat sink), the heat sinks H3, H4 (second heat sink), and the heat sink HD (heat sink for diodes), the heat sinks H1, H2 (first heat sink), the heat sinks H3, H4 (second heat sink), and the heat sink HD (heat sink for diodes) are provided at different positions. Then, the cooling air flows through each of the heat sinks H1 to H4, HD through a predetermined air passage, and the heat dissipation of the right inverter elements S1, S2 and the left inverter elements S3, S4, which are high heat generating elements, as well as the diode bridge 21 is promoted.

As shown in FIG. 7, the middle substrate 16 is provided with heat sinks H5 and H6 (third heat sinks) as metal members on which a pair of middle inverter elements S5 and S6 are mounted. In the example of FIG. 7, two heat sinks H5 and H6 are provided along the flow direction (left-right direction) of the cooling air. One heat sink H5 is provided with a middle inverter element S5, and the other heat sink H6 is provided with another middle inverter element S6.

As described above, the fan device 9 is provided with two air outlets, a front air outlet 92h and a left air outlet 93h. Of these two air outlets, the cooling air blown out through the front air outlet 92h (one of the air outlets) is diverted toward the right inverter elements S1 and S2 (first inverter elements), the left inverter elements S3 and S4 (second inverter elements), and the diode bridge 21. The cooling air blown out through the left air outlet 93h (the other air outlet) is guided to the middle inverter elements S5 and S6 (third inverter elements).

In this way, air paths are provided to guide the cooling air blown out from the fan device 9 so that it is diverted toward the right inverter elements S1 and S2 (first inverter elements), the left inverter elements S3 and S4 (second inverter elements), the middle inverter elements S5 and S6 (third inverter elements), and the diode bridge 21. Such air paths are described using FIG. 10.

FIG. 10 is a bottom view of the board cover 12 provided in the induction heating cooker 100. As shown in FIG.
10 is a bottom view of the rear surface of the board cover 12 as viewed from below, and is therefore left-right reversed from FIG.
10, the board cover 12 is provided with a plurality of ribs Ra, Rb, Rc, and Rd and board cover partitions Rs and Rt that extend downward from the lower surface (rear surface) of the board cover 12. Note that the air passage W1 that guides the cooling air from the fan device 9 to the heat sinks H1 and H2 of the right inverter elements S1 and S2 (see FIG. 7) is configured to include the board cover partition Rt (near the heat sinks H1 and H2), another board cover partition Rs, parts of the left and right boards 15 (see FIG. 7), and parts of the board cover 12.

In addition, the air passage W2, which guides the cooling air from the fan unit 9 to the heat sinks H3, H4 of the left inverter elements S3, S4 (see Figure 7), is composed of the board cover partition Rs, the rib Ra, parts of the left and right boards 15 (see Figure 7), and parts of the board cover 12.
In addition, the air passage W3, which guides the cooling air from the fan unit 9 to the heat sink HD of the diode bridge 21 (see Figure 7), is composed of the board cover partition Rt (near the heat sink HD), the rib Rb, parts of the left and right boards 15 (see Figure 7), and parts of the board cover 12.

As mentioned above, the diode bridge 21 (see FIG. 7) is located relatively far away from the right inverter elements S1 and S2 (see FIG. 7) and the left inverter elements S3 and S4 (see FIG. 7). Therefore, relatively low-temperature cooling air is guided to the heat sink HD of the diode bridge 21, promoting heat dissipation from the diode bridge 21.

In addition, air passage W4, which guides the cooling air from fan device 9 to heat sinks H5, H6 of middle inverter elements S5, S6 (see FIG. 7), is configured to include ribs Rc, Rd, a part of middle board 16 (see FIG. 7), and a part of board cover 12. This allows relatively low-temperature cooling air to be guided to heat sinks H5, H6 of middle inverter elements S5, S6 as well.

＜Effects＞
According to the first embodiment, the cooling air is guided so as to be diverted to each of the right inverter elements S1 and S2, the left inverter elements S3 and S4, the middle inverter elements S5 and S6, and the diode bridge 21. Therefore, the thermal influence between the electronic components is suppressed, and each electronic component can be appropriately cooled. Therefore, the size of the fan device 9 can be reduced and the power consumption can be reduced.

In addition, in conventional induction cooking devices, three or more high heat generating elements such as inverter elements and diode bridges are mounted on a board in a line (for example, Patent Document 1). In such a configuration, the temperature of the cooling air rises due to heat absorption from the high heat generating elements, making it difficult for the high heat generating elements on the downwind side to dissipate heat. In addition, when the induction cooking device consumes a lot of power, the amount of heat generated per unit time by the diode bridge increases, so the rotation speed of the fan device is increased to prevent insufficient cooling, which can lead to an increase in power consumption.

In contrast, in the first embodiment, only two high heat generating elements (e.g., right inverter elements S1 and S2: see FIG. 7) are mounted in a row along the air flow direction. Therefore, even if the rotation speed of the fan device 9 is relatively slow, the high heat generating element on the downwind side (e.g., right inverter element S2) is appropriately cooled. Furthermore, the pressure loss of the cooling air in the process of passing through the high heat generating elements is reduced, making it easier for the cooling air to pass through.

In addition, the diode bridge 21 connected to the DC side of the right inverter circuit 23 (see FIG. 8), the left inverter circuit 24, and the center inverter circuit 25 is integrated (commonized) into one. Furthermore, because the grounded busbar (wire 30b in FIG. 8, etc.) is commonized, the area of the left and right boards 15 can be reduced, and the induction heating cooker 100 can be made more compact.

In addition, since the middle inverter elements S5 and S6 are mounted on the middle board 16, they are relatively far from the diode bridge 21 mounted on the left and right boards 15. Therefore, there is almost no thermal effect between the middle inverter elements S5 and S6 and the diode bridge 21, and the middle inverter elements S5 and S6 can be efficiently cooled by cooling air. In addition, for example, when a radiant heater is used instead of the middle heating coil 8, the left and right boards 15 can be reused almost as they are with a configuration that omits the board stand 14 (see Figure 3) and middle board 16 (see Figure 3). Therefore, even if the model of the induction heating cooker is different, many parts can be standardized, which reduces development costs and manufacturing costs.

Second Embodiment
In the second embodiment, a radiant heater 40 (see FIG. 11) is provided instead of the middle heating coil 8 (see FIG. 2) described in the first embodiment. The second embodiment is different from the first embodiment in that the induction heating cooker 100A (see FIG. 12) includes left and right substrates 15 (see FIG. 12) but does not include the middle substrate 16 (see FIG. 7 of the first embodiment). The rest of the second embodiment is the same as the first embodiment. Therefore, only the parts that are different from the first embodiment will be described, and the description of the overlapping parts will be omitted.

FIG. 11 is a plan view of the induction heating cooker 100A according to the second embodiment with the top plate removed.
As shown in FIG. 11, the induction heating cooker 100A includes a right heating coil 6 (first heating coil), a left heating coil 7 (second heating coil), a radiant heater 40, and a fan device 9.

The radiant heater 40 is a spiral heating wire (e.g., nichrome wire) that generates heat when an electric current flows through it. In the example of FIG. 11, the radiant heater 40 is installed on the upper side of the board cover 12, at the back center in a plan view. The radiant heater 40 is connected to predetermined electronic components mounted on the left and right boards 15 (first boards).

FIG. 12 is a plan view including the left and right boards 15 and the fan unit 9 provided in the induction heating cooker 100A.
12 differs from the configuration of the first embodiment (see FIG. 7) in that the substrate stand 14 and the middle substrate 16 are not provided, but other aspects (such as the configuration of the left and right substrates 15) are the same as those of the first embodiment. In the example of FIG. 12, the other substrates are not particularly connected to the connection portions 29 (fixing portions 29a and hooks 29b) provided on the edges of the left and right substrates 15 (first substrate). Electricity is supplied to the radiant heater 40 from the left and right substrates 15 via a predetermined wiring, causing the radiant heater 40 to generate heat.

As shown in FIG. 12, the cooling air blown out through the front outlet 92h (one of the two outlets of the fan device 9, the front outlet 92h and the left outlet 93h, is divided toward the right inverter elements S1 and S2 (first inverter elements), the left inverter elements S3 and S4 (second inverter elements), and the diode bridge 21. The cooling air blown out through the left outlet 93h (the other outlet) of the fan device 9 is guided to the space G near the connection part 29 consisting of the fixing part 29a and the hook 29b.

＜Effects＞
According to the second embodiment, even in the configuration in which the radiant heater 40 is provided, it is possible to appropriately cool high heat generating elements such as the right inverter elements S1 and S2, the left inverter elements S3 and S4, and the diode bridge 21. In addition, the induction heating cooker 100A requires only one printed circuit board 15 on which the right inverter elements S1 and S2, the left inverter elements S3 and S4, the diode bridge 21, etc. are mounted, so that the induction heating cooker 100A can be made compact.

In addition, for example, even if an intermediate heating coil 8 (see FIG. 2) as described in the first embodiment is provided instead of the radiant heater 40, the left and right substrates 15 can be used as is, which allows parts to be standardized between different models, thereby reducing development and manufacturing costs.

<<Variations>>
Although the induction heating cookers 100 and 100A according to the present invention have been described in each embodiment above, the present invention is not limited to these descriptions and can be modified in various ways.
For example, in each embodiment, the ribs Ra to Rd (see FIG. 10) of the board cover 12 and the board cover partitions Rs, Rt (see FIG. 10) are used to divide the cooling air in a predetermined manner, but the present invention is not limited to this. For example, the casing 9c of the fan device 9 may be provided with three or more air outlets, and the cooling air may be divided in a predetermined manner through these air outlets.

Furthermore, the circuit configuration of the induction heating cooker 100 is not limited to the example shown in Fig. 8, and various modifications are possible. For example, a chopper circuit (not shown) that steps up or steps down a DC voltage may be provided as appropriate.
In addition, in the first embodiment, the induction heating cooker 100 (see FIG. 2) is described as having the right heating coil 6, the left heating coil 7, and the middle heating coil 8. However, for example, the middle heating coil 8 may be omitted.

In the first embodiment, the DC side of the middle inverter circuit 25 (see FIG. 8) is connected to the diode bridge 21 mounted on the left and right boards 15, but this is not limited to the configuration. For example, a separate diode bridge (not shown) may be provided that is connected to the DC side of the middle inverter circuit 25, and this diode bridge may be installed on the middle board 16.

In addition, in each embodiment, a configuration has been described in which a board cover partition Rs is provided to separate the heat sinks H1, H2 of the right inverter elements S1, S2 (see FIG. 7) from the heat sinks H3, H4 of the left inverter elements S3, S4, but this board cover partition Rs may be omitted. The cooling air may be diverted in a predetermined manner in front of (upwind from) the high heat generating elements such as the right inverter elements S1, S2 and the left inverter elements S3, S4.

In addition, in each embodiment, the heat sinks H1 and H2 are individually provided for the right inverter elements S1 and S2, but the heat sinks for the right inverter elements S1 and S2 may be shared. The same is true for the heat sinks for the left inverter elements S3 and S4 and the middle inverter elements S5 and S6.
In addition, in each embodiment, a configuration has been described in which a heat sink is installed on each of the high heat generating elements such as the right inverter elements S1, S2, etc., but the heat sink may be omitted as appropriate, or a specified heat dissipation component other than a heat sink may be installed.

In addition, in each embodiment, the right inverter elements S1 and S2, the left inverter elements S3 and S4, and the center inverter elements S5 and S6 are described as being IGBTs, but this is not limited to this. In other words, a specified switching element other than an IGBT may be used as each of the inverter elements described above. Furthermore, multiple types of switching elements may be mixed.

In addition, in each embodiment, the induction heating cooker 100, 100A is described as a built-in type IH cooking heater equipped with a grill chamber 4 (see FIG. 1), but this is not limited to this. In other words, each embodiment can be applied to various types of induction heating cookers other than built-in type IH cooking heaters.

In addition, the embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to having all of the configurations described. In addition, it is possible to add, delete, or replace part of the configuration of the embodiment with other configurations.
Furthermore, the above-mentioned mechanisms and configurations are those considered necessary for the explanation, and do not necessarily show all mechanisms and configurations of the product.

1 Main body 6 Right heating coil (first heating coil)
7 Left heating coil (second heating coil)
8 Middle heating coil (third heating coil)
9 Fan device 92h Front air outlet (one of the air outlets)
93h Left air outlet (the other air outlet)
12 Board cover 15 Left and right boards (first board)
16 Middle board (second board)
21 Diode bridge 23 Right inverter circuit (first inverter circuit)
24 Left inverter circuit (second inverter circuit)
25 Middle inverter circuit (third inverter circuit)
29 Connection part 29a Fixing part 29b Hook 40 Radiant heater 100, 100A Induction heating cooker E Electronic component G Space H1, H2 Heat sink (first heat sink)
H3, H4 Heat sink (second heat sink)
H5, H6 Heat sink (third heat sink)
HD Heat sink (heat sink for diodes)
S1, S2 Right inverter element (first inverter element)
S3, S4 Left inverter element (second inverter element)
S5, S6 Middle inverter element (third inverter element)
W1, W2, W3, W4 Wind path

Claims (3)

a substrate cover disposed so as to cover a first substrate disposed on the main body;
A first heating coil and a second heating coil are provided on an upper side of the substrate cover,
a fan device for blowing air between the first board and the board cover in a vertical direction;
The first substrate has:
A first heat sink is disposed on a first inverter element of a first inverter circuit connected to the first heating coil;
A second heat sink is disposed on a second inverter element of a second inverter circuit connected to the second heating coil;
a diode heat sink disposed in a diode bridge connected to the DC side of each of the first inverter circuit and the second inverter circuit;
the first heat sink, the second heat sink, and the diode heat sink are disposed on a side from which air is blown out of the fan device,
a left -right distance between the first heat sink and the diode heat sink and a left-right distance between the second heat sink and the diode heat sink are longer than a left-right distance between the first heat sink and the second heat sink, when a surface on which a front panel is provided is regarded as a front surface,
a surface on which the front panel is provided is defined as a front surface, and air blown out from the fan unit flows in a front-rear direction through each of the first heat sink, the second heat sink, and the diode heat sink.
Induction heating cooker. In claim 1,
an air passage is provided in the board cover to guide the cooling air blown out from the fan device so as to be diverted to each of the first inverter element, the second inverter element, and the diode bridge;
Induction heating cooker. In claim 2,
the first heat sink, the second heat sink, and the diode heat sink are provided at different positions in a direction perpendicular to a flow direction of cooling air;
Induction heating cooker.