JP6730209B2 - Induction cooker - Google Patents

Description

The present invention relates to an induction heating cooker.

An induction heating cooker is a cooker that uses Joule heating due to eddy currents generated in the bottom of a metal pot when magnetic field lines generated by passing a high-frequency current through the heating coil pass through the bottom of the pot. .. During heating and cooking, not only the bottom of the pan, but also the heating coil, the control board, and the like generate heat. Therefore, a fan device is used to blow and cool the heating coil and the control board.

In addition, in the induction heating cooker installed in the system kitchen, in addition to cooking on the top plate, those that can cook such as grilled fish using a grill with a heat source such as an electric heater are mainstream. Has become.

In such a conventional induction heating cooker, the main parts to be cooled are a plurality of heating coils and a control board. Due to the structure, the heating coils are near the top plate above the main body, and the control board is a surplus on the side of the grill. It is generally configured to be stored in a space.

In addition, the intake port and the exhaust port of the main body arranged in the system kitchen are, as shown in Patent Document 1, "the intake port provided on the outer surface front part or the bottom part of the main body outer shell or both, and the outside of the main body outer shell through the intake port. It is equipped with a fan that inhales air and blows it to the heat generation part inside the main body to forcibly cool it, and an exhaust port that is an outlet for cooling air provided in the upper rear part of the main body's configuration. The structure is such that the spillage due to boiling or bumping in the cooking pot and the steam in the pot do not easily flow into the main body.

When the induction cooker is stored in the system kitchen frame, the outer edge of the top plate forms a flange to hold the main body, and the liquid spilled over the top plate during heating of the cooking pot ( Packing is provided on the outer peripheral side of the top plate so that water cannot easily enter through the gap between the system kitchen frame and the top plate (flange portion).

Alternatively, even if the heating operation is accidentally performed with the top plate cracked or damaged, a structure that suppresses the spilled liquid from entering the charging part (exposed part of the circuit pattern) of the control board. Has been taken.

Further, not only the failure due to the above liquid intrusion, but an unexpected failure may occur depending on the use environment, the use frequency, the type of pot used, and the like. At that time, in the case of service at the time of failure or repair, it is necessary to remove the top plate and further replace parts of the control board arranged below the heating coil. In terms of serviceability, it is desirable that the connector or the like is provided at a position where it can be easily accessed because the easier the work of mounting and removing the parts such as the sensor, the quicker the repair/replacement.

On the other hand, since most system kitchen frames in Japan have specified dimensions, the maximum external dimensions of induction heating cookers are also roughly determined, which is ideal for cooling heating coils and control boards within a limited space. It is necessary to construct a simple air path.

In order to efficiently heat the cooking pot with the heating coil, it is important to optimally lay out the electronic components and connectors of the inverter circuit that feeds the heating coil. The optimum layout generally means that the distance between the components is short (high integration), the components are hardly affected by other electronic components such as a power supply (low noise), and the components are arranged in an ideal circuit pattern. In Patent Document 2, there is a control board having a control section for driving and controlling the heating section below a heating section (heating coil) support plate, and a fan motor cools heat generated by components on the control board. Similarly, it is housed in a box-shaped outer casing provided with an opening above the heating unit supporting plate, and a plurality of inverter circuits are formed on one control board on one surface. The components are arranged so that there are no wirings (jumper wires, etc.) between the control boards and across the electronic components on the control board.

JP, 2011-3372, A JP, 2014-142125, A

In the induction heating cooker of Patent Document 1, a plurality of control boards are vertically stacked and housed on the side of the grill cabinet, and a circuit configuration having a plurality of wirings connecting the control boards is provided. It easily occurs and heating efficiency deteriorates. Furthermore, a fan device that cools the heating coil and the control board is housed in a narrow space, and various members are arranged in the vicinity of the intake/exhaust portion of the fan device. Therefore, the turbulence of the intake air flow due to the distribution of the wind speed generated by the arrangement of the members and the increase of the ventilation resistance deteriorate the ventilation performance of the fan device, which causes the cooling performance of the components to deteriorate and the fan noise to increase. Further, the laminated board structure does not have good serviceability, and for example, in the case of replacing the board in the lowermost layer, it is necessary to remove most of the components, which requires enormous work time and labor.

On the other hand, in the case of an induction heating cooker having a grill cabinet, which is the most mainstream configuration, a plurality of fan devices and a control board arranged side by side are housed between the grill cabinet and the top plate as in Patent Document 2. Is difficult because the mounting volume of the board is small. In a general system kitchen, the gap between the grill and the top plate is only about 60 mm, and the volume of the grill is about half or more of the width of the main body. For this reason, when the control board is arranged on the substantially same surface and is to be housed in the main body, the gap in the height direction from the grill to the heating coil is about 20 to 30 mm, and the component mounting volume is conventionally (for example, Patent Document 1 ) Less than. Here, a heat sink that dissipates heat by mounting electronic components that generate high heat is mounted on the control board, and a heat sink having a height of about 40 to 50 mm is used for the control board that is stacked and stored on the side of the grill cabinet. There is. Cooling of electronic components that generate high heat is determined by the volume of the heat sink and the amount of air flow to the heat sink. Therefore, if the heat sink volume is made small, a large air volume (improve the air velocity between fins) or a fine fin shape (fin heat dissipation area) is required. A large fan device with high pressure is required.

Further, when the control board is arranged below the heating coil, the positional relationship between the control board and the top plate becomes closer than in the conventional case. Therefore, compared to the state in which the control substrate is concentrated and laminated on one side as in Patent Document 1, the possibility that the control substrate and the liquid come into contact with each other due to the liquid intrusion becomes higher. In other words, the distance between the exhaust port of the top plate and the control board and the distance between the outer edge of the top plate and the control board become much shorter. Furthermore, when the top plate is cracked or damaged, liquid may enter the entire surface of the top plate.

Therefore, according to the present invention, the control board is arranged below the heating coil so that the electronic parts can be optimally arranged, and the control board layout is provided with a circuit pattern that drives with high efficiency, and a liquid intrusion prevention structure is provided. An object of the present invention is to provide an induction heating cooker having an air-cooling structure that realizes low noise operation by a ventilation path with suppressed ventilation resistance and serviceability in case of failure.

In order to solve the above problems, an induction heating cooker according to the present invention includes a main body, a top plate installed on an upper surface of the main body, a heating coil provided below the top plate, and a heating coil below the heating coil. An inverter board that is arranged and supplies a high-frequency current to the heating coil, a fan device that cools the inverter board, and a board cover that mounts the heating coil and substantially covers the inverter board are provided. In the induction heating cooker, the inverter board is provided with a relay connector at a position not covered by the board cover in a top view of the main body, and a region above the relay connector and not covered by the board cover is The air passage extending from the fan device to the inverter board is configured to be covered with a removable lid.

The details will be described in the embodiment for carrying out the invention.

ADVANTAGE OF THE INVENTION According to this invention, in the component mounting which arrange|positioned the inverter board in planar shape, the circuit noise was hard to occur, the stable IH operation, the low noise operation by the ventilation path which suppressed ventilation resistance, and the serviceability at the time of failure were put in parallel. An induction heating cooker having an air cooling structure can be provided.

The perspective view of the induction heating cooker of Example 1. Exploded perspective view of the induction heating cooker of the first embodiment. Side sectional view taken along the line AA of FIG. Front sectional view taken along the line BB of FIG. Front sectional view taken along the line CC of FIG. Layout inside the substrate cover taken along the line D-D in FIG. Circuit diagram of the current resonance inverter of the first embodiment Top view showing the flow of air in the induction heating cooker Side sectional view of the heating coil of Example 1 when installed Exploded perspective view of the heating coil of Example 1 Exploded perspective view of the induction heating cooker of the second embodiment. Sectional side view of the heating coil of Example 2. A perspective view of a substrate cover and a heating coil of Example 3. Sectional side view of the induction heating cooker of the third embodiment. Exploded perspective view of the induction heating cooker of the modification of Example 1. Front sectional drawing of the induction heating cooking appliance of the modification of Example 1.

An induction heating cooker that is an embodiment of the present invention will be described in detail with reference to the drawings, taking a built-in type IH (Induction Heating) cooking heater equipped with a grill for heating an object to be cooked with an electric heater as an example. To do. Note that, as shown in FIG. 1 and the like, front-rear, up-down, left-right are defined with reference to the line of sight of the user facing the induction heating cooker Z (see FIG. 1).

<Structure of induction heating cooker>
The induction heating cooker Z of the first embodiment is a device in which an eddy current is generated at the bottom of a cooking pot (not shown) made of metal, and the eddy current causes Joule heat to heat the cooking pot itself. 1 is a perspective view of the induction heating cooker Z, FIG. 2 is an exploded perspective view of FIG. 1, FIG. 3 is a side sectional view taken along the line AA of FIG. 1, and FIG. 4 is a line BB of FIG. 1 is a front sectional view taken along line C-C in FIG. 1, and FIG. 6 is a layout inside the substrate cover taken along line D-D in FIG.

As shown in the exploded perspective view of FIG. 2, the induction heating cooker Z mainly includes a main body 1, a top plate 2, heating coils 3a, 3b, 3c, and substrates placed on substrate stands 73a, 73b. 7a and 7b, substrate covers 6a and 6b provided to cover the substrates 7a and 7b, and a fan device 9. In the induction heating cooker Z having such a configuration, the eddy current is generated by causing a high-frequency current of, for example, about 20 kHz to 40 kHz to flow through the heating coils 3a, 3b, and 3c to change the magnetic flux with time.

The heating coils 3a, 3b, 3c are installed below the top plate 2, and a temperature sensor 34 for detecting the temperature of the pan bottom is installed near the center thereof. Further, the heating coils 3a, 3b, 3c are arranged on the downstream side of the fan device 9, and after the cooling air blown from the fan device 9 cools the substrate covers 6a, 6b and the substrates 7a, 7b below the lid portion 6c. The heating coils 3a, 3b, 3c are cooled via the discharge part 60a at the front corner of the main body. The heating coils 3 a, 3 b, 3 c are coils through which a high-frequency current flows by driving an inverter circuit described later, and are mounted on the coil base 31. In this embodiment, the heating coils 3a, 3b, 3c are provided one at each of the right, left, and center depths in plan view. The coil base 31 is supported by three support portions 32 (for example, springs), and an upward biasing force is applied by the support portions 32. As a result, the heating coil is pressed against the lower surface of the top plate 2, and the distance between the pan to be cooked and the heating coils 3a, 3b, 3c is kept constant.

The grill storage 5 on the left side of the front of the main body 1 is provided with an inlet (not shown) for sliding back and forth to set an object to be cooked (not shown). On the right side of the front of the main body 1, there is provided an operation panel P2 mainly for adjusting the heating condition in the grill case 5. The top plate 2 is composed of a plate-shaped glass (not shown) on which the pan to be cooked is placed and a frame portion (not shown) that holds the four sides of the plate-shaped glass, and is installed from above the main body 1. There is. The top plate 2 includes a three-neck pot placement portion 21 corresponding to the installation positions of the three heating coils 3a, 3b, and 3c, an operation portion 22 for adjusting the heat of the cooking pot, and an exhaust opening H2. have. The exhaust openings H2 are a plurality of holes for discharging the air blown out from the fan device 9, and are provided on the rear side (right side/left side) of the top plate 2.

The main body 1 is a housing having an outer shell corresponding to the space (predetermined left/right width/front/back width/height) in which the induction heating cooker Z is installed, and has a box shape (concave shape) with an open top. There is. The grill cabinet 5 is provided on the lower left side of the main body 1, and the board stands 73a and 73b are placed on the partition plate 1b that covers the grill cabinet 5, on which the boards 7a and 7b and the fan unit 9 are configured. The side casing 90b and the impeller 91 are arranged in a plane. Further, as shown in FIG. 3, the discharge port 95 which is the outflow portion of the fan device 9 is arranged at a height including the surfaces of the substrates 7a and 7b.

Here, the fan device 9 is a centrifugal fan including an impeller 91, casings 90a and 90b provided with the impeller 91 sandwiched vertically, and a motor 92 that penetrates the casing 90a and is connected to the impeller 91. That is, the impeller 91 is housed in a space surrounded by the casing 90a provided with the motor 92 and the casing 90b provided with the intake port 9a, and the rotating shaft 92a of the motor 92 is prevented from coming into contact with the casings 90a, 90b. It is rotatably supported by. Therefore, the fan device 9 has the rotary shaft 92a of the impeller 91 in the up-down direction of the main body 1, sucks air from below, and blows air out in two directions from the side discharge port 95. Further, as shown in FIG. 3, the intake port 9a of the casing 90b has a bell mouth shape. That is, the fan device 9 is arranged on the upstream side of the substrates 7a and 7b, the motor 92 is driven to take in air from the intake port 9a, and the air is diverted in two directions from the discharge port 95, and the heat sinks 8a of the substrates 7a and 7b. Cooling air is supplied toward 8b.

Further, as shown in FIG. 2 and the like, the boards 7a and 7b are covered with board covers 6a and 6b and a lid portion 6c, respectively, and an upper casing 90a forming the fan device 9 is arranged side by side with the board covers 6a and 6b. It is arranged. Further, the heating coils 3a, 3b, 3c, the display portion P1 and the like are installed above them, and the top plate 2 is further provided so as to cover from above.

Here, the electronic components 71 on the substrates 7a and 7b are integrated circuits, inverter circuits, capacitors, resistors, etc. used for supplying high-frequency currents to the heating coils 3a, 3b and driving the fan device 9. Is. The board bases 73a and 73b are insulating members (resin members) for fixing the boards 7a and 7b, and are fixed to the inner wall of the main body 1 and the partition plate 1b.

A relay connector 77 is provided on the left side (center side of the main body) of the substrate 7a, and is connected to the signal line of the temperature sensor 34 installed on the heating coils 3a, 3b, 3c. Further, a detachable lid portion 6c is fitted in a region between the substrate covers 6a and 6b which is not covered by the substrate cover. Therefore, the signal line of the temperature sensor can be easily removed from the relay connector 77 by removing the lid portion 6c that covers the upper portion of the relay connector 77. Further, the space between the relay connector 77 and the lid portion 6c serves as an air passage extending from the fan device 9 to the left side substrate 7b. According to the configuration of this embodiment, the air passage extending from the fan device 9 to the left-side substrate 7b can have a wide cross-sectional area, and thus a small ventilation resistance can be applied toward the heat sink 8b of the left-side substrate 7b. A flow that efficiently supplies cooling air can be configured.

Since the relay connector 77 is located on the right side substrate 7a, which is the shortest distance to the heating coils 3a, 3b, and 3c, that is, in the gap between the heating coils 3a, 3b, and 3c in the top view of the main body, maintenance is performed. At times, the lid 6c can be easily attached and detached, and the signal line of the temperature sensor 34 can be easily detached from the relay connector 77 without moving the heating coils 3a, 3b, and 3c largely. ..

Further, since it is not necessary to take an extra length of the signal line of the temperature sensor 34 provided in each heating coil 3a, 3b, 3c from the relay connector 77, the wiring can be easily arranged, and, for example, the ventilation resistance of the air passage can be suppressed. This makes it possible to mount components with high reliability such that electromagnetic noise on the substrates 7a and 7b is unlikely to occur.

If the lid portion 6c is located in the gap between the heating coils 3a, 3b, 3c in a top view of the main body, even if the lid portions 6c are fixed to the substrate covers 6a, 6b with screws, it is troublesome to attach and detach the lid portion 6c. It does not take.

FIG. 3 is a side cross-sectional view taken along the line AA shown in FIG. 1, mainly showing the positional relationship between the heating coil 3a on the right side and the fan device 9. An intake opening H1 for taking in air from the outside by driving the fan device 9 is provided on each of the back sides of the main body 1. Further, the air blown into the main body 1 from the fan device 9 is discharged from the exhaust opening H2 provided at the rear of the top plate 2. In addition to the rear of the main body 1, if an intake opening is provided on the lower front side, for example, it becomes easier to take in relatively low temperature air into the main body 1. Further, by providing the intake opening H1 on the back side far from the grill case 5 located on the left side (see FIG. 2 ), it is possible to make it difficult to suck the air having a high temperature taken in through the intake opening H1. In addition, in the induction heating cooker Z of the present embodiment, a hollow portion (chamber portion F0) is provided below the fan device 9, that is, on the right side of the grill case 5. The chamber part F0 provided between the intake opening H1 and the fan device 9 relaxes the wind velocity distribution of the air flowing in from the intake opening H1 and supplies a less disturbed airflow along the bell mouth of the intake port 9a.

Therefore, separation of the flow at the impeller 91 downstream of the intake port 9a can be suppressed, and the impeller 91 can be blown with high efficiency. Therefore, the fan device 9 can be rotationally driven with a low noise and a large air volume, and becomes an induction heating cooker with a low operating noise. That is, when the fan device 9 is incorporated in the induction heating cooker Z, a predetermined pressure increase of the impeller 91 can be ensured, so that the rotational speed does not need to be increased more than necessary and the operation can be performed with low noise.

Further, the lower casing 90b of the fan device 9 projects downward from the partition plate 1b (see FIG. 2) on which the board base 73a is placed, so that the impeller having a large diameter and a large blade thickness can be easily housed. ing.

The fan device 9 in the induction heating cooking has a sufficient margin to the ventilation resistance (for example, 100 to 200 Pa) in the main body 1 so that the fan device 9 has a sufficient margin of pressure-air flow, and the air flow required for cooling at low speed ( Since, for example, 1.0 to 1.5 m ³ /min) is obtained, the substrates 7a and 7b and the heating coils 3a, 3b and 3c can be efficiently cooled, and noise reduction during operation can be suppressed easily. .. Further, if the ventilation resistance from the intake opening H1 to the exhaust opening H2 is small, the air volume required for cooling can be flown even if the rotation speed of the fan device 9 is suppressed, so that the noise can be further reduced.

The air blown out from the fan unit 9 flows on the substrate 7a installed in the gap between the substrate table 73a and the substrate cover 6a (F1), and moves toward the heating coil 3a installed on the substrate cover 6a downstream of the substrate cover 6a. It flows through the gap of the top plate 2 (F2). In this embodiment, a discharge portion 60a (see FIG. 2) that supplies air from the side toward the heating coil 3a is provided on the front side of the substrate cover 6a. The opening of the discharge part 60a faces the side surface of the heating coil 3a, and the opening surface cannot be seen even when viewed in plan from above. This is effective in preventing the liquid from entering the substrate cover through the opening of the ejection portion 60a even if the liquid enters through the cracked portion of the top plate.

In addition, since the intake port 9a communicating with the impeller 91 is located below the substrate table 73a, the discharge port 95 of the fan device 9 blows air obliquely upward toward the substrate cover 6a. This configuration suppresses the temperature rise of the substrate cover 6a caused by providing the substrate 7a and the heating coil 3a in close proximity via the substrate cover 6a. Since the heating coil 3a during cooking rises to a temperature close to 200° C., the temperature of the substrate cover 6a rises due to the radiant heat of the heating coil 3a. Therefore, by forming the discharge port 95 toward the substrate cover 6a and biasing the main stream to the substrate cover 6a side, thermal deformation due to radiant heat is suppressed.

In the present embodiment in which the substrate 7a (7b) is provided above the grill cabinet 5, the distance between the heating coils 3a (3b, 3c) and the substrate 7a (7b) is also greater than in the configuration in which the substrate is provided on the side of the grill cabinet. However, as in the present configuration, the main flow of the air blown by the fan device 9 is inclined to the substrate cover 6a (6b), so that the substrate cover 6a can be used to approach the substrate cover 6a. The heat transferred to 7a can be prevented, and the entire components in the main body 1 can be efficiently cooled.

Here, the air (F2) that cools the heating coil 3a and flows through the gap between the substrate cover 6a and the top plate 2 is discharged toward the exhaust opening H2 at the rear of the main body 1. The exhaust opening H2 is covered with an exhaust cover 25 in which a plurality of small diameter holes are provided in a metal plate, and it is difficult for a liquid (not shown) that flows in when a spillage or the like occurs on the top plate to directly enter. There is. The exhaust cover 25 is removable and can be removed and cleaned when it becomes dirty. Further, the liquid that has passed through the exhaust cover 25 receives the liquid drops that have passed through the small-diameter holes and drops on a wide surface by the water receiving portion 94 provided below the exhaust cover 25, buffers them, and flows into the fan device 9 side. I try not to. A grid-shaped partition 94a is provided between the water receiving portion 94 and the motor 92 to prevent liquid from entering the inside of the main body 1.

Further, in the configuration of the present embodiment, by disposing the fan device 9 in the vicinity of the exhaust opening H2, it is possible to increase the distance from the right exhaust opening H2 to the substrate 7a, and the liquid permeates into the charging portion of the substrate. It has a difficult structure. Therefore, the possibility that liquid will enter the substrate 7a with respect to the exhaust opening H2 can be extremely reduced, and the present embodiment has a highly safe structure in which failure does not easily occur. In the left exhaust opening H2, as shown in FIG. 2, a water receiving portion 1a is provided behind the partition plate 1b, and the droplets that have passed through the exhaust cover 25 fall to the rear of the grill case 5. Therefore, it is difficult to enter the substrate cover 6b side.

FIG. 4 is a front sectional view taken along line BB shown in FIG. 1 and FIG. 5 is taken along line CC shown in FIG. 1. The positional relationship between the heating coils 3a, 3b and 3c and the substrates 7a and 7b is shown. Is shown. First, the heating chamber 50 in the grill case 5 is, for example, a space for arranging foods such as fish grills, and an electric heater (upper heater 51, lower heater 52) as a heat source and a grill for placing fish and the like. 54 and a saucer 53 arranged below the grill 54. As described above, the heating chamber 50 is arranged in the left region of the main body 1 in a plan view, and the internal saucer 53 and the like are slidable in the front-rear direction with respect to the main body 1.

The heat source of the heating chamber 50 is not limited to the electric heater, and the food may be heated by microwaves, steam, or a combination thereof. Alternatively, a temperature controller may be provided to heat the oven. In this embodiment, the induction heating cooker Z provided with the grill case 5 having a width equal to or larger than 1/2 of the main body is shown.

As described above, the boards 7a and 7b on which the electronic components 71 are mounted and the fan device 9 that allows air to flow through the air passages in the board covers 6a and 6b are provided in the vicinity of the exhaust opening H2 of the top plate 2. It is arranged. Therefore, in FIG. 4 showing the front cross section of the heating coil 3c and FIG. 5 showing the front cross section of the heating coils 3a and 3b, the right region in the main body 1 is a space (chamber part F0). Further, as shown in FIG. 5, in the present embodiment, the substrate 7a is arranged below the right heating coil 3a and the substrate 7b is arranged below the left heating coil 3b in a divided manner. An inverter circuit for supplying electric power to 3a is mounted on the substrate 7b, and an inverter circuit for supplying electric power to the heating coil 3b on the left side and the heating coil 3c on the inner side is mounted. The substrates 7a and 7b are arranged in a space in which the substrate base 73a and the substrate cover 6a and the substrate base 73b and the substrate cover 6b are vertically combined, and the space serves as an air passage (F1). In the induction heating cooker Z of the present embodiment, a plurality of boards are arranged in a plane so that each inverter board can be replaced when parts are replaced due to a failure or the like, and parts can be replaced efficiently. Therefore, the service workability is improved.

FIG. 6 is a layout of the substrate and the fan device in the substrate cover taken along the line D-D shown in FIG. 1, and shows the relationship between the flow of air supplied from the fan device 9 and the substrates 7a and 7b. As shown in FIG. 6, the heat sink 8 a of the board 7 a, the relay connector 77, and the heat sink 8 b of the board 7 b are respectively arranged at positions close to the fan apparatus 9 on the downstream side of the discharge port 95 of the casing 90 a of the fan apparatus 9. There is. The heat sinks 8 a and 8 b are radiators that absorb heat from the high heat generating element 72, which is an electronic component having a high heat generating property, and radiate heat to the air flowing in through the fan device 9. The heat sinks 8a and 8b each have fins (not shown) having a predetermined surface area and are installed on the substrates 7a and 7b. The discharge port 95 of the fan device 9 splits into two parts facing the heat sinks 8a and 8b, and guides a predetermined flow rate of air to the heat sinks 8a and 8b as the motor 92 is driven. Since the high heat-generating elements 72 that form the inverter circuit are installed on the heat sinks 8a and 8b, high cooling performance can be obtained by disposing them on the most upstream side near the fan device 9. In addition, from the fan device 9 to the exhaust opening H2, the air passage of the air flowing through the heat sink 8b becomes longer than the air passage of the air flowing through the heat sink 8a.

In this embodiment, ribs 66a, 66b, 66c extending downward (on the substrate side) are provided on the upper wall surfaces of the substrate covers 6a, 6b (see FIG. 6) to form two air passages toward the heat sinks 8a, 8b. doing. Therefore, the air passage to the heat sink 8a constitutes the ventilation duct 65a by the substrate cover 6a serving as the air passage upper surface, the ribs 66a and ribs 66b extending downward from the substrate cover 6a serving as the air passage side surface, and the substrate 7a serving as the air passage lower surface. To be done. On the other hand, the air passage to the heat sink 8b includes a substrate cover 6b and a lid portion 6c which are the air passage upper surface, ribs 66c and ribs 66b extending downward from the substrate cover 6b which is the air passage side surface, a substrate 7a which is the air passage lower surface, and a substrate. The ventilation duct 65b by 7b is comprised. That is, the air duct cross-sectional area of the air duct 65b having a long air passage to the exhaust opening H2 is made larger than that of the air duct 65a to reduce the overall air flow resistance and the load on the fan device 9 to reduce the operating noise. Is suppressed.

The heat sinks 8a and 8b are installed on the upstream side near the fan device 9. That is, the heat sinks 8a and 8b are arranged so that the high heat generating element 72, which has the largest heat generation amount, is cooled first by the air flowing in through the discharge port 95. In this way, by disposing the heat sinks 8a and 8b in the vicinity of the discharge port 95 and concentrating the flow by the ribs 66a, 66b and 66c, the high heat generating element 72 can be effectively cooled. The ribs provided on the substrate covers 6a and 6b may be appropriately provided in consideration of air flow distribution to other electronic components 71. Further, the height of the ribs may be appropriately determined according to the situation of air volume distribution, and may be provided not on the inside of the substrate cover but on the upper wall surface side on the heating coil side to serve as a coil cooling air passage. Further, instead of the rib shape, an unevenness may be provided on the upper wall surface of the substrate cover according to the outer shape of the component.

Next, the circuit diagram of the current resonance inverter used in the induction heating cooker Z of the present embodiment will be described with reference to FIG. 7. Here, an example in which a half bridge circuit of a current resonance inverter is configured by the high heat generating element 72 shown in FIG. 6 is shown, and FIG. 7A shows a half for a left heating coil 3b and a back heating coil 3c. A bridge circuit diagram, FIG. 7B is a half bridge circuit diagram for the heating coil 3a on the right side.

As a circuit generally used in the induction heating cooker, there is a half bridge circuit of a current resonance inverter. For example, as shown in FIG. 7B, two IGBTs (Insulated Gate Bipolar Transistor) 72a and DB (Diode Bridge) 72x are provided. Composed. Further, as shown in FIG. 7A, in the present embodiment, the DB of the inverter that feeds the heating coils 3b and 3c is shared. The common use of the DB is such that two half bridge circuits are arranged on one substrate 7b with the DB interposed therebetween, and as shown in FIG. 7, the high heat generating elements 72 are arranged in the front-back direction of the main body. And used as a cooling air passage.

FIG. 8 is a top view showing a flow in the main body 1 from the fan device 9 to the exhaust opening H2 through the top plate 2. As shown in FIG. 8, the air discharged from the fan device 9 flows from the rear to the front in the ventilation ducts 65a and 65b near the left and right center of the main body 1 (see FIG. 6). Then, the main flow of air passing through the ventilation duct 65a bends to the right side of the main body, cools the electronic component 71 (not shown) on the substrate 7a in the substrate cover 6a, and flows (cools) to the heating coil 3a downstream thereof. ).

Further, the main air of the air passing through the ventilation duct 65b is bent to the left side of the main body to cool the electronic component 71 (not shown) on the board 7b in the board cover 6b, and also to cool the heating coil 3b downstream thereof. In other words, the cooling air of the fan device 9 has a main stream branched into the left and right sides of the main body in the substrate covers 6a and 6b. As a result, the flows are easily guided to the downstream exhaust opening H2 efficiently without crossing. Further, in this configuration, since the cooling air passage is composed of two layers inside the substrate covers 6a and 6b (F1) and below the top plate 2 (F2), the main flow from the fan device 9 collides with the wall surface. The number of parts that change the flow direction is reduced, and a structure with reduced ventilation resistance can be realized.

FIG. 9 is a side sectional view when the heating coil 3a is installed, and FIG. 10 is a perspective exploded view of the heating coil 3a. As shown in FIGS. 9 and 10, the heating coil 3a is placed on a coil base 31 radially containing rod-shaped ferrites 33 that are magnetic bodies. For example, an elastic spring or the like is used to form the heating coil 3a. It is held by the support portions 32 at three places via the support groove 31a on the outer periphery of the portion 31. The ferrite 33 is arranged so that the magnetic flux around the heating coil 3a, which is generated by the high frequency current supplied from the inverter board 7a to the heating coil 3a, is directed toward the cooking pot. The ferrite 33 may have a fan shape instead of a rectangular shape with respect to the heating coil. If it is fan-shaped, it becomes easy to cover the lower surface of the heating coil with ferrite, and leakage of magnetic flux can be reduced.

The support portion 32 is installed on the substrate covers 6a and 6b and the casing 90a (see FIG. 2) and supports the coil base 31 from below. In this embodiment, the support portion 32 is composed of a spring inserted into the support groove 31a, and while the positioning of the heating coil 3a is performed, the coil base 31 is pressed against the top plate 2 side, and the heating coil 3a and the top plate 2 are aligned. Close to each other.

A contact-type temperature sensor 34, such as a thermistor, which indirectly detects the temperature of the cooking pot from the contact temperature with the top plate 2 is arranged near the center of the coil base 31 via a sensor base 34a. .. The sensor base 34a has a shaft portion (not shown) penetrating the support hole 31b at the center of the coil base 31, and a spring 34b provided on the shaft portion allows the temperature sensor 34 on the sensor base 34a to move to the top. It is configured to be pressed against the plate 2. The smaller the gap between the heating coil 3a and the top plate 2 is, the better the electrical coupling between the heating coil 3a and the cooking pan is. Therefore, the smaller the gap is, the more efficient the heating can be. The heating coil 3a of the present embodiment has a configuration in which a litz wire formed by twisting a plurality of strands is wound in a spiral shape, and the heating coil 3a includes an outer litz wire 30a and an inner litz wire 30b, and is doubled in the radial direction. It has a divided structure. The above configuration is an arrangement effective for uniformly heating the cooking pot, and if a temperature sensor is separately arranged between the outer Litz wire 30a and the inner Litz wire 30b, the bottom of the cooking pot is The sensor can be placed close to the highest temperature part, and the cooking pot temperature can be controlled appropriately.

Here, as the temperature sensor, a non-contact sensor such as an infrared sensor may be used instead of the thermistor. Further, as the number of temperature sensors provided in the heating coil 3a increases, it is possible to detect a plurality of positions in the pan placing portion 21 (see FIG. 1), so that cooking temperature control such as pan temperature adjustment and safety controllability such as empty heating can be achieved. Can be increased. A plurality of relay connectors 77 are provided on the board in order to connect the sensor installed on the heating coil to the board during assembly. Further, the power supply cable from the substrate 7a to the heating coil 3a is generally constructed by terminals provided on the coil base 31, but by providing the terminals below the coil base 31, the mounting efficiency can be improved. it can. At this time, since the connection to the relay connector 77 is made after the heating coil 3a is installed, the structure becomes easier to remove and the serviceability is improved.
<Modification>
FIG. 15 and FIG. 16 are modified examples of the present embodiment. As shown in these drawings, this modified example has a configuration in which a rib 66 extending toward the relay connector 77 is provided below the lid portion 6c. There is.

In the first embodiment, as shown in FIG. 6, the air passage toward the heat sink 8a and the air passage toward the heat sink 8b are separated by using the three ribs 66a, 66b, and 66c. The ribs 66 form the ventilation duct 65a to the substrate 7a and the ventilation duct 65b to the substrate 7b, and the air volume distribution to the ventilation ducts 65a and 65b can be adjusted by the position, inclination, and shape of the rib 66.

Therefore, according to the present modification, the ribs 66 provided on the lid portion 6c do not have to provide the ribs 66a, 66b, 66c (see FIG. 6) of the substrate covers 6a, 6b, but have a simple structure and the ventilation ducts 65a, 65b. Can be configured. In addition, the complicated shapes of the substrate covers 6a and 6b are reduced, and attachment and detachment are facilitated and service work is facilitated.
<Heating operation and air flow in the board case>
The pan to be cooked is placed on the pan placing portion 21 (corresponding to the heating coil 3a on the right side) of the top plate 2, and the user operates the operating portion 22 (see FIG. 1) to start the heating process. The operation unit 22 is a touch key, and can be operated by touching a key printed on the top plate 2.

High frequency current is supplied to the heating coil 3a located below the cooking pot from the inverter circuit shown in FIG. 7(b) in response to a command from a control device (not shown) to induction-heat the cooking pot. .. When the cooking pan is induction-heated by the heating coil 3a, in addition to the heating coil 3a, the high heat generating element 72 and the electronic component 71 forming the inverter circuit also generate heat.

When the heating process is started, the fan device 9 is driven in response to a command from a control device (not shown). When the fan device 9 is driven, a negative pressure is generated on the inflow side of the impeller 91, and the air that has flowed from the intake opening H1 through the chamber part F0 is sucked into the fan device 9. The air discharged from the fan device 9 is divided into the ventilation ducts 65a and 65b in the substrate covers 6a and 6b, and absorbs heat from the heat sink 8a on the substrate 7a. The high heat generating element 72 (72a, 72x) is cooled by heat dissipation through the heat sink 8a, and the other electronic components 71 mounted on the substrate 7a are also cooled by heat exchange with air. The air that has cooled the substrate 7a flows from the discharge portion 60a above the substrate cover 6a toward the heating coil 3a, cools the heating coil 3a, and then is discharged through the exhaust opening H2. The air passing through the ventilation duct 65b also flows inside the substrate cover 6b and is discharged through the exhaust opening H2.
<Effect>
According to the present embodiment described above, circuit noise is less likely to occur due to component mounting that maximizes the circuit pattern area, stable IH operation, low noise operation by a ventilation path with suppressed ventilation resistance, and serviceability at the time of failure. It is possible to provide an induction heating cooker having an air-cooling structure in which the above are arranged side by side.

The second embodiment is different from the first embodiment in the configuration of the substrate covers 6a and 6b, the heating coil, and the top plate 2, but is otherwise the same as the first embodiment. Therefore, the different part will be described, and the description of the part overlapping with the first embodiment will be omitted.

FIG. 11 is an exploded perspective view of the induction heating cooker according to the second embodiment, showing the component configuration of the substrate covers 6a and 6b and the heating coils 3a, 3b and 3c. FIG. 12 is a side sectional view of the heating coil shown in FIG. As shown in FIG. 11, the substrate covers 6a and 6b according to the present embodiment are provided with an opening 63 and a discharge portion 60a. The opening provided above the substrate covers 6a and 6b has an opening area larger than that of the ejection unit 60a (see FIG. 2) of the first embodiment. The larger the opening area, the lower the average wind speed and the ventilation resistance when passing through the discharge part 60a.

That is, by providing the discharge portion 60a with a large opening area shown in FIG. 11, the overall ventilation resistance from the intake opening H1 to the exhaust opening H2 is reduced. Therefore, the fan device 9 can efficiently blow air with a small fan power. Further, as shown in FIG. 12, since the cooling air can be supplied from below the heating coil 3a, the heating coil can be efficiently cooled with a low pressure loss.

On the other hand, when the liquid enters due to cracks in the top plate 2 or the like, in order to protect the electronic components 71 of the substrates 7a and 7b exposed from the ejection portions 60a provided on the substrate covers 6a and 6b, the heating of the present embodiment is performed. In the coil 3a, a waterproof plate 35 larger than the outer shape of the heating coil 3a is installed in the gap between the coil 3a and the top plate 2. The waterproof plate 35 is not limited as long as it is a material that does not affect the induction heating of the cooking pot. For example, if it is a mica plate, it is inexpensive and easy to mold, so that it is easy to manufacture. Since the discharge parts 60a of the substrate covers 6a and 6b provided below the heating coils 3a, 3b and 3c of the present embodiment can be covered with the waterproof plate 35, liquid intrusion when the top plate is cracked can be prevented as in the first embodiment. It is possible to provide an induction heating cooker that suppresses, is safe, and has high reliability.

The third embodiment is different from the first embodiment in the configuration of the substrate covers 6a and 6b and the display portion P1, but is otherwise the same as the first embodiment. Therefore, the different part will be described, and the description of the part overlapping with the first embodiment will be omitted.

FIG. 13 is a perspective view of the substrate cover and the heating coil of the induction heating cooker according to the third embodiment, and shows another example of the air passage configuration by the substrate covers 6a and 6b. Further, FIG. 14 is a side sectional view of the induction heating cooker showing the main flow of the cooling air on the substrate covers 6a and 6b of FIG. As shown in FIG. 13, in the present embodiment, the substrate covers 6a and 6b on the front side of the main body are open surfaces, and are placed on the downstream side of the heat sinks (8a and 8b, see FIG. 2) into which the air blown from the fan device 9 flows. It constitutes a large space. With this configuration, air easily flows between the fins of the heat sink, and the ventilation resistance of the air passage can be reduced. In this embodiment, as shown in FIG. 14, the air passage F1 for cooling the substrate 7a (7b) and the air passage F2 for cooling the heating coils 3a (3b, 3c) are referred to as the substrate cover 6a (6b). It is configured so as to be partitioned and separated at the portion P1. The fitting portion (not shown) of the substrate cover 6a (6b) and the display portion P1 may form a labyrinth seal (non-contact seal) with a rib or the like, or a packing or the like (contact seal). It may be. If the fitting portion is provided with an opening for cooling the heating coil 3a (3b) to form the discharge portion 60a, cooling air is supplied to the heating coil 3a (3b) from an arbitrary position to improve cooling efficiency. it can. If the collar portion 61 is provided on the display portion P1 and the flow direction of the cooling air is limited, the heating coil 3a (3b) can be cooled more effectively.

Z induction cooker,
1 body,
2 top plate,
21 pot placement section,
22 operation part, 3a, 3b, 3c heating coil,
31 coil base,
32 instruction section,
34 temperature sensor,
5 grill storage,
6a, 6b substrate cover,
6c lid,
60a discharge part,
65a, 65b ventilation duct,
66, 66a, 66b, 66c ribs,
7a, 7b substrate,
71 electronic components,
72 (72a, 72b, 73b, 73x) high heat generating element,
73a, 73b substrate stand,
77 relay connector,
8a, 8b heat sink,
9 fan device,
9a intake port,
90a, 90b casing,
91 Impeller,
92 motor,
95 outlet,
F0 chamber part,
H1 intake opening,
H2 exhaust opening,
P1 display, P2 operation panel

Claims (5)

Body,
A top plate installed on the upper surface of the main body,
A heating coil provided below the top plate,
An inverter board arranged below the heating coil and supplying a high-frequency current to the heating coil,
A fan device for cooling the inverter board;
An induction heating cooker including the heating coil and a substrate cover that substantially covers the inverter substrate,
The inverter board is provided with a relay connector at a position not covered by the board cover in a top view of the main body,
An induction heating cooker, characterized in that a region above the relay connector and not covered by the substrate cover is covered with a detachable lid part to form an air passage from the fan device to the inverter substrate. The heating coil and the inverter board are respectively provided in plurality,
Each inverter board is arranged in a substantially planar shape,
The induction heating cooker according to claim 1, wherein the lid portion is arranged in a gap between the plurality of heating coils in a top view of the main body. The induction heating cooker according to claim 2, wherein a rib extending toward the relay connector is provided on a lower surface of the lid, and the air flow distribution to the plurality of inverter boards is controlled by the rib. A display unit is arranged below the top plate and on the front side of the main body,
The guide according to any one of claims 1 to 3, wherein the board cover and the display section separate a space in which the plurality of heating coils are installed from a space in which the plurality of inverter boards are installed. Heating cooker. The induction heating cooker according to claim 4, wherein an opening for blowing air to the heating coil is provided in a gap between the display unit and the substrate cover.

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