JP2011127896A - Heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that a service life of a punching board shielding microwaves at a bottom surface section of a cooking chamber, while allowing magnetic flux to pass therethrough, is short as use frequency is high in a case of business use, and it takes a long time for its replacement and repair, which degrades operational efficiency of the device. <P>SOLUTION: A circular opening is formed on a bottom plate 71 forming a bottom section of the cooking chamber, and an annular bottom plate fitting 73 to which the punching board 72 is welded, is detachably mounted thereon. By fixing the bottom plate fitting 72 to the bottom plate 71 by combining a fixing section 75 by engagement of a weld bolt fixed to the bottom plate 71 and a nut, and a pressure contact section 78 by simple pressing of a projecting section 73b, the necessary strength can be ensured while improving work efficiency. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a combined cooking device having both high-frequency heating means and induction heating means for cooking food stored in a substantially hermetically sealed cooking chamber.

  Microwave ovens directly heat high-frequency foods using microwaves, so they are very effective for high-speed cooking such as warming, but they cannot burn foods and are not suitable for scorched cooking. On the other hand, induction heating (IH) cookers, which have been popularized in recent years, are ideal for cooking by cooking or cooking for cooking by heating a magnetic metal pan or the like by induction heating. Therefore, in order to compensate for the drawbacks of cooking by high frequency heating as described above, a composite cooking device using induction heating cooking has been conventionally known.

  For example, in the heating and cooking apparatus described in Patent Document 1, an induction heating coil is disposed below the bottom surface of a substantially box-shaped cooking chamber, and a cooking dish placed on the bottom surface of the cooking chamber is guided by the magnetic flux generated from the coil. It can be heated. On the other hand, a magnetron is arranged outside the cooking chamber, and the microwave generated from the magnetron is supplied into the cooking chamber through a power supply port formed on the side surface of the cooking chamber, and thereby the food placed on the cooking pan. Can be heated at high frequency. This type of heating cooking apparatus is suitable for performing burnt-eye cooking or stew cooking on foods stored in a container such as a pan or a frying pan having a configuration capable of induction heating.

  Of course, such a cooking device is convenient for general household use, but it is also very useful for business use such as a restaurant chain store and a convenience store where shortening of cooking time is particularly required. One of the major differences between the general household use and the business use in the state of use of the cooking device is the frequency of use. In other words, in the case of business use, it is desirable to operate the cooking device as efficiently as possible, that is, to increase the operation efficiency, so it is assumed that the operation is performed almost continuously for a long time without interruption. Is done.

  When the induction heating coil is disposed below the bottom surface of the cooking chamber as in the above-described configuration, the bottom surface of the cooking chamber is configured by a member through which magnetic flux passes, for example, a punching plate having a large number of small holes perforated. The Such a punching plate is hardly heated by induction, but is slightly heated by the action of a part of magnetic flux penetrating the member. Further, the temperature rises due to heat conduction such as a temperature rise of the induction heating coil itself. Therefore, when induction heating is repeated almost continuously as described above, heat accumulates on the punching plate and the temperature rises, which is a considerable high temperature that cannot occur in ordinary household use. May be reached. For this reason, in business use, the punching plate is consumed by heating, and damage such as tearing is likely to occur.

  Therefore, it is often necessary to replace the punching plate particularly in a cooking device for business use. On the other hand, as described above, it is important to increase the operating efficiency of the apparatus as much as possible for business use, and therefore it is anxious to shorten the time required for maintenance such as repair as much as possible. However, in the conventional cooking device as described above, the replacement work of the punching plate is very troublesome. This is because, generally, a box-shaped cooking chamber has a structure in which the other five surfaces (top surface portion, bottom surface portion, rear surface portion, and left and right side surfaces) other than the front surface portion opened and closed by a door are integrated. In this case, in order to replace the punching plate on the bottom surface, it is necessary to replace the entire cooking chamber. Since the cooking chamber is equipped with various members on its outer surface, This is because it will be disassembled once and the cooking cabinet will be replaced and reassembled. Furthermore, after the reassembly, various mechanical adjustments such as a door switch operation adjustment are necessary, and the above-described repair is very troublesome. For this reason, it is inevitable that even a manufacturer's service person takes a considerable amount of time for repair, and in order to save such trouble, the apparatus itself is often replaced with a new one. For these reasons, in the conventional cooking device, the cost associated with repair / exchange for damage to the punching plate is considerably high.

  Moreover, in the apparatus described in Patent Document 1, the bottom portion of the cooking chamber is formed of a thin plate-like member that reflects a microwave while allowing magnetic flux such as the punching plate as described above to pass through, and a dielectric is formed thereon. A non-magnetic mounting plate having heat resistance is provided, and an induction heating coil is installed below the bottom of the cooking cabinet. Since the alternating magnetic flux generated from the induction heating coil decreases as the distance from the coil decreases, the induction heating coil is preferably as close to the bottom surface of the container as the object to be heated in view of induction heating efficiency. However, as described above, a plate-like member such as a mounting plate and a punching plate is inserted between the bottom surface of the container and the induction heating coil, and depending on the contents, the heat of the container at 200 to 300 ° C. In order to suppress the transmission to the induction heating coil, it is necessary to provide an appropriate gap between them.

  For these reasons, while it is preferable to ensure a sufficient gap between the bottom surface of the container and the induction heating coil and to increase the induction heating efficiency as much as possible, it has not been taken into consideration in the past, and is sufficiently high. It could not be said that heating efficiency was obtained.

JP 2004-327260 A

  The present invention has been made to solve the above-mentioned problems, and in a combined-type cooking device having both high-frequency heating means and induction heating means, the cooking time can be shortened by increasing the heating efficiency of induction heating compared to the prior art. And to reduce power consumption.

In order to achieve the above object, the present invention includes a substantially hermetically sealed box-shaped cooking chamber, a magnetron for generating microwaves for high-frequency heating of food stored in the cooking chamber, and the microwave High-frequency heating means including a waveguide that guides the inside of the cooking chamber, and induction heating means including an induction heating coil that generates an alternating magnetic flux for induction heating the heating element accommodated in the cooking chamber. In the cooking device provided,
The induction heating coil is installed outside one of the wall surfaces of the cooking chamber, and at least a part of the wall surface has a magnetic flux passage portion that allows a magnetic flux generated from the induction heating coil to pass therethrough and prevents a microwave from passing therethrough. Furthermore, a plate member made of a low-loss dielectric material and heat resistant material is disposed inside the magnetic flux passage portion of the wall surface, and the thickness from the inner surface of the plate member to the magnetic flux passage portion The relationship between the distance in the direction l and the distance L in the thickness direction from the inner surface of the plate member to the inner surface of the induction heating coil is set as l ≦ L / 2 and L−l ≧ 3 mm. It is said.

  Therefore, according to the heating cooking apparatus which concerns on this invention, the heating efficiency of the induction heating by inserting a magnetic flux passage part, preventing the leakage from the microwave cooking chamber in the case of high frequency heating reliably by a magnetic flux passage part Can be suppressed. In addition, the magnetic flux passage part itself is also slightly heated by induction heating, but heat conduction to the induction heating coil can be suppressed by separating from the induction heating coil. Furthermore, since the gap between the induction heating coil and the magnetic flux passage portion becomes large, air can easily flow, and the cooling effect of both the induction heating coil and the magnetic flux passage portion is enhanced.

  Moreover, the leakage of the microwave from the cooking chamber in the case of high frequency heating can be prevented efficiently by making the distance between a magnetic flux passage part and the induction heating coil inner surface 3 mm or more.

  Further, in the heating cooking apparatus according to the present invention, the induction heating coil is accommodated in a flat box-shaped resin case having a surface facing the cooking chamber wall surface, and is provided on the outer surface of the case and the peripheral edge of the opening. It is good to set it as the structure which forms the metal layer and has arrange | positioned the said case so that the peripheral edge part may contact the outer surface of the kitchen wall surface which is metal.

  According to this configuration, since leakage of magnetic flux from between the peripheral edge of the opening of the case and the wall surface of the cooking chamber can be reduced, the magnetic metal member arranged outside the case is undesirably heated. It can be avoided.

  Moreover, as one aspect of the cooking device according to the present invention, temperature detection means for detecting the temperature of the magnetic flux passage section, and control means for controlling the power supplied to the induction heating coil based on the temperature detected by the temperature detection means It can be set as the structure provided with these.

  In this configuration, for example, when the temperature detected by the temperature detection unit exceeds a predetermined value, the control unit reduces or stops the power supplied to the induction heating coil. For example, if the pan is boiled or heated abnormally for a long time, the temperature of the magnetic flux passage may rise abnormally. In such a situation, the magnetic force generated from the induction heating coil weakens or disappears. The heat generation of the magnetic flux passage part due to the is suppressed. Thereby, in addition to abnormal heating of the magnetic flux passage part itself, abnormal temperature rise of the induction heating coil due to heat conduction from the magnetic flux passage part and other abnormal temperature rises of other peripheral electrical components can be prevented.

  As described above, according to the heating and cooking apparatus according to the present invention, an object to be heated such as a pot accommodated in the cooking chamber while effectively preventing leakage of microwaves to the outside of the cooking chamber during high-frequency heating. On the other hand, it is possible to efficiently heat the magnetic flux by penetrating. Thereby, while being able to shorten cooking time, the power consumption is suppressed and it contributes also to the reduction of cooking cost.

  Hereinafter, a cooking device according to an embodiment of the first to fourth inventions will be described with reference to the drawings.

  1 is an external perspective view of the cooking device of the present embodiment with the door open, FIG. 2 is a top plan view (a) and a front plan view (b), and FIG. 3 is an AA ′ arrow in FIG. FIG.

  As shown in FIGS. 1 and 2, the cooking device includes a substantially rectangular parallelepiped casing 1, and a cooking chamber 3 having a front surface opened is formed inside the casing 1. The front opening of the cooking chamber 3 is opened and closed by a side-opening door 2. A punching plate for preventing microwave leakage and a heat-resistant glass capable of seeing through the inside of the cooking cabinet 3 are installed in the central portion 2a of the door 2, and around the door 2, the cooking cabinet 3 is closed when the door 2 is closed. A microwave leakage prevention structure is provided that prevents the microwave in the cooking cabinet 3 from leaking to the outside in contact with the front opening peripheral frame portion 3f. In addition, an operation panel having a key input unit 11 in which a plurality of operation keys are arranged and a display unit 12 such as a segment LCD is disposed in a position that is not hidden when the door 2 is closed on the front surface of the housing 1. The cook instructs various cooking conditions and start / stop of operation using the key input unit 11, and the display unit 12 displays such cooking conditions and remaining operation time. In addition, on the lower side of the front surface of the housing 1 and below the door 2, an air inlet 4 for taking in outside air for cooling each part in the housing 1 to be described later is widely formed.

  As shown in FIG. 3, the cooking cabinet 3 has a substantially rectangular parallelepiped box shape having a rear surface portion 3a, a top surface portion 3b, a bottom surface portion 3c, a left side surface portion 3d, and a right side surface portion 3e as wall surfaces, and the front opening is as described above. When closed by the door 2, it is almost sealed. Each wall surface of the cooking chamber 3 is considered to be a case where each is a separate member and a case where a member in which a plurality of wall surfaces are integrated (for example, a U-shaped plate member) is used. By fixing, each wall surface except for the front surface is integrated into a box-like body. The integrated member constituting the cooking cabinet 3 is a wall surface member in the present invention. In the cooking chamber 3, as shown in the figure, for example, a container 90 in which a food 91 to be cooked is stored is stored. In the present cooking apparatus, in order to cook the food 91, the high-frequency (microwave) heating means for cooking the microwave oven and the container 90 as the heating element in the first and third inventions are indirectly heated. And an induction heating means for cooking the food 91.

  That is, as a high-frequency heating means, a magnetron 5 that generates microwaves is installed at the rear upper part of the rear surface portion 3a of the cooking cabinet 3, and the microwaves generated by the magnetron 5 are guided to extend forward in the upper part of the casing 1. It propagates through the pipe 6 and is guided to the microwave diffusion chamber 7 provided in the top surface portion 3b of the cooking chamber 3. In the microwave diffusion chamber 7, there is provided a radiation antenna 9 that is driven to rotate in a substantially horizontal plane by an antenna drive motor 8, so that the microwave is reflected on the top surface portion 3b of the cooking chamber 3 as indicated by the dotted arrow in FIG. It is radiated from the power feeding port while being diffused into the cooking cabinet 3. The food 91 in the container 90 is cooked by the action of the microwave.

  In addition, the top | upper surface part 3b of the cooking chamber 3 is not horizontal, but is provided in the shape of an inclination so that it may fall toward back. Thereby, when the water vapor | steam generate | occur | produced in the cooking chamber 3 has condensed on the top | upper surface part 3b, the condensed water flows to the back side along the top | upper surface part 3b. For this reason, when the container 90 and food are taken in and out, water drops are less likely to be caught on the cook's hand.

  On the other hand, as an induction heating means, an induction heating coil 82 for induction heating of the container 90 itself is installed in a substantially horizontal plane below the bottom surface portion 3c of the cooking cabinet 3, When a high frequency current is supplied to the induction heating coil 82 from an inverter circuit to be described later, an alternating magnetic flux is generated, and the magnetic flux passes through the bottom surface portion 3c and enters the cooking chamber 3, for example, a container 90 made of magnetic metal. Across the bottom of the. Then, an eddy current is induced at the bottom of the container 90 by the induction action of the alternating magnetic flux, the container 90 becomes high temperature due to Joule heat, and the food 91 contained in the container 90 is cooked. The structure of the induction heating unit including the induction heating coil 82 and the bottom surface portion 3c of the cooking cabinet 3 will be described in detail later.

  FIG. 4 is an electric system configuration diagram of the cooking device according to the present embodiment. As shown in FIG. 4, the main control unit 20, which is the center of control, is configured with a CPU at the center, and the main control unit 20 receives a key input signal from the key input unit 11 and the door switch 14 from the door 2. A door opening detection signal for recognizing the open / close state is input from the temperature sensor 86 as a temperature detection signal for a punching plate constituting a part of the bottom surface portion 3c. The main control unit 20 drives an induction heating inverter circuit (IH inverter circuit) 24 via an induction heating (IH) driving unit 18, and the induction heating coil 82 which is a part of the configuration of the inverter circuit 24. A high frequency current is supplied. The main control unit 20 drives a high frequency heating inverter circuit (EM inverter circuit) 25 via a high frequency heating (EM) driving unit 19 and supplies driving power to the magnetron 5 to generate microwaves.

  The power supply circuit 23 includes a power switch 231, a noise filter 232 common to high-frequency heating / induction heating, rectifier circuits 233, 234 independent of induction heating and high-frequency heating, and the like. The DC power converted from the AC power is supplied to the induction heating inverter circuit 24 and the high frequency heating inverter circuit 25. The main control unit 20 that receives drive power from the power supply circuit 23 via the DC power supply circuit 26, via the load drive unit 21, in addition to the antenna drive motor 8, three cooling fan motors, that is, EM cooling fan motors. 16, the operations of the IH cooling fan motor 17 and the coil cooling fan motor 84 are controlled. Furthermore, the display unit 12 outputs a display control signal about the setting information of the cooking course, the operation status, and the like to perform display, and the buzzer 13 is sounded as necessary. As will be described later, the EM cooling fan motor 16 is mainly for cooling the high-frequency heating inverter circuit 25, and the IH cooling fan motor 17 is mainly for cooling the induction heating inverter circuit 24. The coil cooling fan motor 84 is mainly for cooling the induction heating coil 82.

  The main control unit 20 includes a ROM in which an operation program is stored. In the process of executing the operation program on the CPU, the operation of the cooker and the operation state of the appliance are monitored by various input signals as described above. While controlling the operation of each of the above parts.

  Next, the structure of the induction heating unit and the structure of the bottom surface portion 3c of the cooking cabinet 3 which are one of the features of the cooking device according to the present embodiment will be described with reference to FIGS. 7 is an exploded view of the bottom surface portion 3c of the cooking cabinet 3 and the induction heating unit 80 located below the bottom portion 3c, FIG. 8 is an assembly structure diagram of the cooking cabinet bottom 70, FIG. 9 is an assembly structure diagram of the induction heating unit 80, and FIG. FIG.

  As shown in FIG. 7, an integrated induction heating unit 80 is installed below the cooking chamber bottom 70 forming the bottom surface portion 3 c of the cooking cabinet 3, while food is accommodated on the cooking cabinet bottom 70. A placement plate 60 for placing the container is placed. The mounting plate 60 needs to allow magnetic flux to pass for induction heating, but needs to be a low-loss dielectric material so that it is difficult to be heated by microwaves at high frequencies. Moreover, since it contacts a container which becomes high temperature, heat resistance is also required. Therefore, the mounting plate 60 can be made of, for example, crystal glass. The mounting plate 60 is formed with a substantially circular recess 61 in which a position for placing an object to be heated is recessed, and the recess 61 is coaxial with the induction heating coil 82.

  As shown in FIG. 8, the cooking cabinet bottom 70 is formed of a stainless steel (SUS304) bottom plate 71 in which a large circular opening forming the bottom of the cooking cabinet 3 is formed. The punching plate 72 and the bottom plate metal fitting 73 which are parts are detachably mounted. Specifically, the bottom plate fitting 73 made of stainless steel (SUS304) corresponding to the frame plate in the present invention has an annular shape, and the same stainless steel punching plate 72 in which a large number of small holes of a predetermined diameter are drilled has a circular shape. Both of these are integrated by a strong fixing method such as spot welding. The plate thickness of the bottom plate 71 and the bottom plate metal fitting 73 is 0.5 mm and its rigidity is high, but the punching plate 72 has a thin plate thickness of 0.1 mm in order to increase the passage efficiency of magnetic flux. Thus, although the punching plate 72 is thin and has low rigidity, the thick bottom plate metal fitting 73 has high rigidity. By fixing the bottom plate metal fitting 73 to the bottom plate 71, the strength of the fixed parts of both is sufficiently increased. Can be high. The bottom plate 71 forms the bottom surface portion 3c of the cooking cabinet 3, and is described as one member in FIGS. 7 and 8, but as described above, the rear surface portion 3a and the side surface portions 3d and 3e are spot-welded. The whole is a single wall member constituting the cooking chamber 3.

  As described above, the punching plate 72 has a function of passing the magnetic flux generated from the induction heating coil 82 and blocking the microwave supplied into the cooking cabinet 3 as described later. The condition of such magnetic flux passage efficiency is mainly determined by the aperture ratio and thickness of the punching plate 72, while the microwave passage prevention condition is mainly determined by the diameter and thickness of the small hole of the punching plate 72. . Therefore, these elements need to be set appropriately. Here, a small hole having a diameter of 1.4 mm provided at intervals of 1.7 mm is used. However, the magnetic flux can pass under the condition that the plate thickness is thin even if the small hole is not necessarily formed.

  Further, the diameter of the punching plate 72 is larger than the outer diameter of the induction heating coil 82 below the punching plate 72, and is actually formed larger with an appropriate margin. Thereby, it is possible to prevent the bottom plate 71 and the bottom plate fitting 73 from being undesirably heated by the magnetic flux generated from the induction heating coil 82.

  In this cooking device, when the punching plate 72 is damaged such as torn, only the punching plate 72 is exchanged without exchanging the bottom plate 71 (strictly, the punching plate 72 and the bottom plate metal fitting 73 are integrated for magnetic flux passage. A mounting structure is employed so that the plate member can be easily replaced. This will be described with reference to FIGS. 11 and 12 are longitudinal sectional views of the mounting structure of the bottom plate metal fitting 73 and the bottom plate 71. FIG. 11 shows a fixing portion 75 and FIG. The attachment structure is provided at 36 locations at substantially equal angular intervals in the circumferential direction of the bottom plate metal fitting 73, and the fixing portions 75 and the press contact portions 78 are alternately provided. In order to prevent leakage of the microwave, the mounting structure needs to be ¼ or less of the wavelength of the microwave. Generally, the wavelength of the microwave used is about 120 mm, so the interval between the mounting structures is 30 mm. It is set as follows.

  As shown in FIG. 11A, in the fixing portion 75, the welding bolt 76 is fixed to the bottom plate 71 by welding or the like so that the screw rod 76a protrudes downward. A screw hole 73a is perforated in the bottom plate metal fitting 73 opposite to this, and a screw rod 76a is inserted into the screw hole 73a, and a nut 77 is screwed into the screw rod 76a from below to tighten. As shown in b), a bottom plate fitting 73 integrated with the punching plate 72 is attached to the bottom plate 71. Since the welding bolt 76 is fixed to the bottom plate 71, it is not necessary to hold the bolt so that it does not rotate when the nut 77 is tightened as described above, and the working efficiency at the time of tightening the nut 77 can be improved.

  On the other hand, as shown in FIG. 12A, in the press-contact portion 78, the bottom surface of the bottom plate 71 is a flat surface, whereas the bottom plate fitting 73 has a convex portion (dwell) 73 b. Since the lower surface of the bottom plate 71 and the upper surface of the bottom plate metal fitting 73 are in contact with each other in the state where the fixing portion 75 adjacent in the circumferential direction is fixed as described above, the pressure contact portion as shown in FIG. In 78, the upper surface of the convex portion 73 b of the bottom plate metal fitting 73 is strongly pressed against the lower surface of the bottom plate 71. Thereby, the high adhesiveness of both contact surfaces is ensured.

  The fixing portion 75 requires time and labor for fixing the welding bolt 76 to the bottom plate 71 and tightening the nut 77, but the pressing portion 78 does not require time and labor. That is, of the 36 mounting structures, half of them are fixed portions 75 and the rest are press-contact portions 78, so that microwaves can be transmitted between the bottom plate 71 and the bottom plate metal fitting 73 while reducing labor and cost of parts. Adhesion at intervals such that leakage does not occur can be ensured, and microwave leakage can be reliably prevented.

  As shown in FIG. 9, the induction heating unit 80 has a coil cooling fan unit 84 including a coil cooling fan motor 84 and a fan driven to rotate by the coil cooling fan unit 84 inside the case 81 whose upper surface is opened. The induction heating coil 82 wound in the shape of a flat plate placed on the coil is accommodated, and a thin mica plate 85 as an insulator is fixed above the induction heating coil 82. That is, the above parts are integrated in the case 81. The case 81 is formed from a resin such as polypropylene (PP) resin, acrylonitrile butadiene styrene (ABS) resin, polycarbonate acrylonitrile butadiene styrene (polycarbonate ABS, PC / ABS) resin, polyethylene terephthalate (PET) resin, phenol resin, etc. The upper edge portion 81a is subjected to metal plating.

  As shown in FIG. 3, when the induction heating unit 80 is installed below the bottom surface portion 3c, the upper edge 81a of the case 81 is in contact with the lower surface of the bottom plate 71. Since a metal layer is formed on the upper edge 81a of 81, the conductivity between the two is ensured, and microwave leakage through the gap can be prevented. That is, even if a part of the microwave radiated into the cooking chamber 3 passes through the punching plate 72, it does not leak to the outside of the induction heating unit 80, so that unnecessary radiation to the surroundings can be further reduced. .

  As shown in FIG. 9, a temperature sensor 86 is provided on the mica plate 85 via a spring 87, and when the induction heating unit 80 is installed below the bottom surface portion 3c, the biasing force of the spring 87 is provided. Thus, the temperature sensor 86 is pressed against and closely contacts the lower surface of the upper punching plate 72. Thereby, the temperature sensor 86 can accurately detect the temperature of the punching plate 72.

  As shown in FIGS. 7 and 10, a mica plate 74, which is an insulator, is arranged on the punching plate 72 as a spacer, so that the gap between the punching plate 72 and the mounting plate 60 can be reduced. Care is taken to keep the distance constant. Such consideration is because a change in the distance of the gap between the punching plate 72 and the mounting plate 60 affects the heating efficiency during induction heating.

  As shown in FIG. 10, since the container 90 that is an object to be heated is placed on the placement plate 60, the upper surface of the placement plate 60 can be regarded as the bottom surface of the container 90. At this time, the distance (distance in the thickness direction) between the upper surface of the induction heating coil 82 as a heating source and the upper surface of the mounting plate 60 is L, and the distance between the punching plate 72 and the upper surface of the mounting plate 60 is l. Think of it as Since the punching plate 72 is as thin as 0.1 mm, the distance l from either the upper surface or the lower surface (or the center) of the punching plate 72 is not much different, but in FIG. 10, the distance from the upper surface of the punching plate 72 is used. .

  Since the alternating magnetic flux generated from the induction heating coil 82 passes through the container 90, the container 90 generates heat, and the magnetic force of the alternating magnetic flux is stronger as it is closer to the induction heating coil 82. Therefore, considering only the heating efficiency, the induction heating coil 82 is preferably as close as possible to the container 90. However, the induction heating coil 82 itself generates heat due to a resistance loss against a high frequency current, and the punching plate 72 itself generates heat due to an eddy current loss generated when a part of the magnetic flux penetrates the plate portion. Therefore, it is necessary to consider these heat dissipations. For this purpose, as shown in the figure, an appropriate gap (coil cooling air path 88) is provided between the induction heating coil 82 and the mica plate 85, and the mica plate 85 is punched. It is necessary to provide an appropriate gap (punching plate cooling air passage 79) between the plates 72. For this reason, it is necessary to secure a distance L between the upper surface of the induction heating coil 82 and the upper surface of the mounting plate 60 to some extent. Therefore, the heating cooking apparatus of this embodiment employs a configuration in which the heating efficiency is as high as possible under the condition that the distance L is set to a certain value.

  FIG. 13 is a graph showing the results of actual measurement of the relationship between the distance L-l between the induction heating coil 82 and the punching plate 72 and the heating efficiency when the distance L is set to 8.5 mm and 11.7 mm. is there. Although it is natural that the heating efficiency is reduced by inserting the punching plate as compared with the case without the punching plate, the distance l between the punching plate 72 and the upper surface of the mounting plate 60 is the same even if the distance L is the same. It can be seen that the heating efficiency decreases greatly as the value is increased. This is considered to be because if the punching plate 72 is disposed in a region where the magnetic force of the magnetic flux generated from the induction heating coil 82 is strong, the loss in the punching plate 72 becomes so much that the heating efficiency is reduced as a whole. Therefore, here, the punching plate 72 is disposed at a position closer to the mounting plate 60 than an intermediate point between the upper surface of the induction heating coil 82 and the upper surface of the mounting plate 60, that is, the distance l becomes L / 2 or less. Are arranged as follows. Thereby, the influence of the reduction in the efficiency of induction heating due to the provision of the punching plate 72 for microwave shielding can be suppressed as small as possible.

  In addition, since the punching plate 72 is shifted toward the side close to the mounting plate 60 between the mounting plate 60 and the induction heating coil 82, the space between the punching plate 72 and the induction heating coil 82 is relatively widened. The coil cooling air passage 88 and the punching plate cooling air passage 79 described above can be easily secured, which is advantageous for promoting the heat radiation of the induction heating coil 82 and the punching plate 72.

  On the other hand, under the condition of l ≦ L / 2, when L is reduced, L−1 is also reduced. However, according to the study of the present inventor, the value of L−l is the degree of microwave leakage from the cooking chamber 3. Has been found to affect. This is because if the induction heating coil 82 is too close to the punching plate 72, the microwaves can easily pass therethrough. Therefore, L-l is set to 3 mm or more so as not to increase microwave leakage.

  In the induction heating unit configured as described above, when a high frequency current is caused to flow from the inverter circuit 24 to the induction heating coil 82 by the induction heating drive unit 18 operating under the control of the main control unit 20, an alternating magnetic flux is generated, and the magnetic flux is punched. It passes through the plate 72 and the mounting plate 60 and enters the cooking chamber 3, and at least crosses the bottom of the container 90 whose bottom is made of magnetic metal. An eddy current is induced at the bottom of the container 90 by the induction action, the container 90 is heated by Joule heat, and the food 91 to be cooked accommodated in the container 90 is heated. As described above, since the relationship among the induction heating coil 82, the punching plate 72, and the mounting plate 60 is appropriately determined, the container 90 can be efficiently induction heated to achieve efficient cooking. Further, as described above, since the bottom plate metal fitting 73 in which the punching plate 72 is integrated with the bottom plate 71 is detachable, when the punching plate 72 is damaged, the manufacturer's service person removes the nut 77 to perform punching. The plate 72 can be easily replaced.

  Moreover, in the heating cooking apparatus of the present embodiment, since the inverter circuits 24 and 25 for driving the induction heating coil 82 and the magnetron 5 are independently provided, the induction heating operation and the high frequency heating operation can be performed simultaneously. In addition, it is possible to operate both of them alternately or independently. Such inverter circuits 24 and 25 include power switching elements (for example, power FETs), and since heat generation during operation is large, it is necessary to appropriately dissipate heat. The induction heating coil 82 generates magnetic flux. However, since the temperature of the induction heating coil 82 increases due to resistance loss or radiant heat from the heating element due to induction heating, it is also necessary to appropriately dissipate heat. Furthermore, as described above, the induction heating coil 82 and the punching plate 72 themselves generate considerable heat. Furthermore, since the cooking chamber 3 may be filled with water vapor or the like during cooking, it is necessary to exhaust the air in the cooking chamber 3.

  Therefore, in the cooking device of the present embodiment, the first fan unit 30 including the EM cooling fan motor 16, the second fan unit 31 including the IH cooling fan motor 17, and the coil for cooling and exhausting as described above. Three third fan units 32 including a cooling fan motor 84 are provided. The air intake ports of these three fan units 30, 31, and 32 are all air intake ports 4 provided in the lower front portion of the housing 1. As described above, the third fan unit 32 is integrated with the induction heating coil 82 in the case 81, and has already been described.

  When the coil cooling fan motor 84 is driven, the fan of the third fan unit 32 rotates, and the outside air sucked from the intake port 4 is sent to the coil cooling air passage 88 and the punching plate cooling air passage 79 described above. Thereby, the heat_generation | fever of the induction heating coil 82 and the punching board 72 can be suppressed.

  Meanwhile, the configuration and operation of the first and second fan units 30 and 31 will be described with reference to FIGS. 4 is a perspective view of the rear side with the housing removed, and FIG. 5 is a perspective view showing a state in which the ventilation path cover is removed in FIG.

  Between the left side surface portion 3d of the cooking chamber 3 and the left side surface portion of the casing 1, and between the right side surface portion 3e of the cooking chamber 3 and the right side surface portion of the casing 1, air passages are provided. Ventilation path covers 33 and 35 extending vertically are provided on the left and right of the rear part. A high frequency heating inverter circuit 25 is provided in the ventilation path cover 33, and a first fan unit 30 is provided below the cover 33. That is, when the EM cooling fan motor 16 of the first fan unit 30 is driven, the outside air sucked from the intake port 4 by the rotating fan rises in the ventilation path cover 33 and the high-frequency heating inverter circuit 25 is Cooling. Then, the warm air is carried rearward through an exhaust duct 34 disposed at the upper portion, and is discharged from the exhaust port formed on the rear surface of the housing 1 to the outside of the machine.

  An induction heating inverter circuit 24 is provided in the ventilation path cover 35, and a second fan unit 31 is provided below the cover 35. That is, when the IH cooling fan motor 17 of the second fan unit 31 is driven, the outside air sucked from the intake port 4 by the rotating fan rises in the ventilation path cover 35, and the induction heating inverter circuit 24 is Cooling. This air is carried forward through an exhaust duct 36 disposed at the upper portion, and supplied into the cooking chamber 3 through an opening (not shown). That is, the first fan unit 30 is used exclusively for cooling the circuit 25, but the second fan unit 31 is used not only for cooling the circuit 24 but also for exhausting dirty air in the cooking cabinet 3. . A number of exhaust holes are formed in the left side surface portion 3d of the cooking chamber 3, and the air in the cooking chamber 3 passes through the exhaust holes and passes through an exhaust duct (not shown) disposed outside the left side surface portion 3d. It is discharged outside.

  As described above, the cooking device of the present embodiment includes the fans that respectively cool the inverter circuits of the induction heating means and the high frequency heating means that can be driven independently, so that the heat radiation of each inverter circuit is sufficiently promoted and continuously. Can be used.

  By the way, although the heat radiation of the punching plate 72 and the induction heating coil 82 is promoted by the air blowing by the third fan unit 32 as described above, for example, the container 90 is in an empty state or covers almost the entire mounting plate 60. When such a steel plate is accommodated and heating for a long time is continued, the punching plate 72 is abnormally heated, and accordingly, the induction heating coil 82 and its surrounding members are abnormally heated and break down. There is a risk of causing this. Therefore, in order to prevent such abnormal heating, the main control unit 20 performs the following control.

  That is, when induction heating is performed, the main control unit 20 reads the temperature detected by the temperature sensor 86 periodically or irregularly, and determines whether or not the temperature exceeds a predetermined upper limit temperature. judge. If the upper limit temperature is not exceeded, the operation is continued, but if the upper limit temperature is exceeded, the inverter circuit 24 reduces the AC wave current supplied to the induction heating coil 82 via the induction heating drive unit 18. To control. Alternatively, the AC wave current supplied to the induction heating coil 82 may be temporarily stopped. Thereby, since the magnetic flux generated from the induction heating coil 82 is reduced or eliminated, the temperature rise of the punching plate 72 is also suppressed. Further, instead of controlling the inverter circuit 24 to reduce the drive power, the cooling effect may be enhanced by increasing the rotational speed of the coil cooling fan motor 84.

  In addition, when cooking in the heating cooking apparatus of a present Example, if it is only cooking by high frequency heating, what is necessary is just to accommodate the foodstuff in the cooking chamber 3, However, in the case of cooking by induction heating, the induction heating coil 82 of Good cooking cannot be performed unless the container 90 is positioned directly above. Therefore, in the above embodiment, the recess 61 is provided in the mounting plate 60. However, for the same purpose, a protrusion that makes it difficult to place the container at an undesired position on the mounting plate 60 is provided. Concavities and convexities that fit into the shape of the mounting plate 60 may be provided on itself. Further, a container position instruction guard or the like, which is a separate member from the mounting plate 60, may be placed on the mounting plate 60 so that the container 90 can be placed accordingly.

  Moreover, as the container 90 used for cooking, as shown in FIG. 10, it is good to use the thing of the structure which coat | covered the handle 90a with the protective cover 90b made from a silicone rubber. Silicone rubber has high heat resistance and is not easily affected by microwaves. Furthermore, even if it approaches the wall surface of the cooking chamber 3, which is made of metal, electric discharge hardly occurs.

  In addition, any of the above-described embodiments is merely an example of the present invention, and it is obvious that modifications, corrections, additions, and the like as appropriate within the scope of the present invention are included in the scope of the claims of the present application. For example, in the above embodiment, the container containing the food is heated by induction heating, but instead of the container, a heating element such as a metal plate is arranged, and the heating element is induction-heated to heat the temperature in the cooking chamber. It is also possible to increase the temperature or to heat the water dropped or supplied to the heating element into water vapor. In general, when the container is induction-heated as described above, it is appropriate to provide an induction heating coil under the bottom wall surface of the cooking chamber, but particularly when the heating element other than the container is induction-heated as described above. In addition, the induction heating coil can be modified to be disposed outside the other wall surface, top surface, rear surface, side surface, etc. of the cooking chamber, and a punching plate for passing magnetic flux is disposed correspondingly.

The external appearance perspective view of the state which opened the door in the heat cooking apparatus by one Example of this invention. The upper surface top view (a) and front plan view (b) of the heating cooking apparatus of a present Example. FIG. 3 is a cross-sectional view taken along line A-A ′ in FIG. 2. The electric system block block diagram of the heat cooking apparatus of a present Example. The perspective view of the back side of the state which removed the housing | casing of the heat cooking apparatus of a present Example. The perspective view which shows the state which removed the ventilation path cover in FIG. The exploded view of the bottom part of a cooking chamber, and an induction heating unit. The assembly structure figure of a cooking chamber bottom part. The assembly structure figure of an induction heating unit. The longitudinal cross-section structure figure of an induction heating unit and a cooking chamber bottom part. The longitudinal cross-sectional view of the fixing | fixed part of the attachment structures of a baseplate metal fitting and a baseplate. The longitudinal cross-sectional view of the press-contact part of the attachment structure of a baseplate metal fitting and a baseplate. The graph which shows the result of having measured the relationship between the distance Ll between an induction heating coil and a punching board, and heating efficiency.

DESCRIPTION OF SYMBOLS 1 ... Housing 2 ... Door 3 ... Cooking chamber 3a ... Rear surface part 3b ... Top surface part 3c ... Bottom surface part 3d ... Left side part 3e ... Right side surface part 3f ... Front opening surrounding frame part 4 ... Inlet 5 ... Magnetron 6 ... Waveguide DESCRIPTION OF SYMBOLS 7 ... Microwave diffusion chamber 8 ... Antenna drive motor 9 ... Radiation antenna 16 ... EM cooling fan motor 17 ... IH cooling fan motor 18 ... Induction heating drive unit 19 ... High frequency heating drive unit 20 ... Main control unit 21 ... Load drive Unit 22 ... Commercial AC power supply 23 ... Power supply circuit 231 ... Power switch 232 ... Noise filter 233, 234 ... Rectifier circuit 24 ... Induction heating inverter circuit 25 ... High frequency heating inverter circuit 26 ... DC power supply circuit 30 ... First fan unit 31 ... 2nd fan unit 32 ... 3rd fan units 33, 35 ... Ventilation path covers 34, 36 ... Exhaust duct 60 ... Mounting plate 70 ... Cooking cabinet bottom 71 ... Bottom 72 ... punching plate 73 ... bottom plate metal fitting 73a ... screw hole 73b ... convex portion 74 ... mica plate 75 ... fixing portion 76 ... welding bolt 76a ... screw rod 77 ... nut 78 ... pressure contact portion 79 ... punching plate cooling air passage 80 ... induction heating Unit 81 ... Case 82 ... Induction heating coil 83 ... Insulating heat insulating plate 84 ... Coil cooling fan motor 85 ... Mica plate 86 ... Temperature sensor 87 ... Spring 88 ... Coil cooling air passage 90 ... Container 90a ... Handle 90b ... Protective cover

Claims (3)

A high-frequency wave including a box-shaped cooking chamber that can be substantially sealed, a magnetron that generates microwaves for high-frequency heating of food stored in the cooking chamber, and a waveguide that guides the microwaves into the cooking chamber. A heating cooking apparatus comprising: heating means; and induction heating means including an induction heating coil that generates an alternating magnetic flux for induction heating the heating element accommodated in the cooking chamber;
The induction heating coil is installed outside one of the wall surfaces of the cooking chamber, and at least a part of the wall surface has a magnetic flux passage portion that allows a magnetic flux generated from the induction heating coil to pass therethrough and prevents a microwave from passing therethrough. Furthermore, a plate member made of a low-loss dielectric material and heat resistant material is disposed inside the magnetic flux passage portion of the wall surface, and the thickness from the inner surface of the plate member to the magnetic flux passage portion The relationship between the distance in the direction l and the distance L in the thickness direction from the inner surface of the plate member to the inner surface of the induction heating coil is set as l ≦ L / 2 and L−l ≧ 3 mm. A cooking device.   The induction heating coil is accommodated in a flat box-shaped resin case whose surface facing the cooking chamber wall surface is open, and a metal layer is formed on the outer surface of the case and the peripheral edge of the opening, and the peripheral edge thereof The cooking device according to claim 1, wherein the case is arranged so that the portion is in contact with the outer surface of the wall surface of the cooking chamber made of metal.   The temperature detection means which detects the temperature of the said magnetic flux passage part, and the control means which controls the electric power supplied to the said induction heating coil based on the temperature detected by this temperature detection means are characterized by the above-mentioned. The cooking apparatus according to the description.