JPH11166736A - Microwave oven - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the unevenness of heating while efficiently heating relatively small food, and besides, prevent to enlarge a heating room. SOLUTION: This microwave oven is provided with a main rotating net 8, so to speak, oval in external form for supporting relatively large food through a food placing saucer 12, at the bottom within a heating room 2. This is provided with an RT motor for rotating the main rotating net 8 and a weight sensor for detecting the weight of placed things. This is provided with an auxiliary rotating net 13 for directly supporting relatively small food, so that it may overlap the locus of rotation of the main rotating net 8, being positioned in the vicinity of the vibration excitation port of the right wall of the heating room 2. This is provided with a motor for an auxiliary rotating net for rotating the auxiliary rotating net 13. When the main rotating net 8 is in stop rotational angle, the upper part of the auxiliary rotating net 13 opens. When the food on the main rotating net 8 is detected by a weight sensor at cooking by heating, both of the main rotating net 8 and the auxiliary rotating net 13 are rotated, and when it is not detected, only the auxiliary rotating net 13 is rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven having a rotating net for supporting food at the bottom of a heating chamber and heating the food by supplying microwaves into the heating chamber.

[0002]

Generally, in a microwave oven, a food placing plate (turntable) is set on a disk-shaped rotating net provided at the bottom of a heating chamber, and the food placing plate is placed on the food placing plate. , And microwaves are supplied into the heating chamber from an excitation port provided on a side wall of the heating chamber, for example, to heat and cook the food. At this time, the food placing plate is rotated to uniformly heat the food.

[0003] However, the above-mentioned conventional foods are effective for heating relatively large foods, but when the foods are relatively small, for example, a bowl of rice.
Since the microwaves cannot always be concentrated on the food, the heating efficiency will not be sufficiently high.
In this case, since the electric field strength near the excitation port is considered to be high, in the case of a small food, for example, without rotating the food placing plate, the food is placed near the excitation port to perform cooking. However, in this case, the side of the food that faces the excitation port is strongly heated, and there is a disadvantage that uneven heating of the food occurs.

Therefore, for example, a small rotary heating unit for centralized heating is provided at the bottom of the heating chamber, near the excitation port, separately from the main food placing plate (rotary net) to provide small food. It is also conceivable to adopt a configuration in which heating is performed by the rotary heating unit. However, in a configuration in which the number of rotary heating units is simply increased, the volume of the heating chamber increases,
Conversely, the heating efficiency of relatively large foods is reduced, and the overall size is increased.

The present invention has been made in view of the above circumstances, and an object thereof is to make it possible to efficiently heat relatively small foods while improving the uneven heating at that time. Moreover, it is an object of the present invention to provide a microwave oven capable of preventing the heating chamber from being enlarged.

[0006]

The microwave oven according to the present invention comprises:
A heating chamber, a microwave supply means for supplying microwaves from an excitation port into the heating chamber, and a main rotation supporting a food provided at a bottom portion of the heating chamber and having a shape in which the outer periphery of a circle is partially lost. A mesh, an auxiliary rotating net provided near the excitation port in the bottom of the heating chamber and arranged to overlap vertically with a rotation locus of the main rotating net, and the main rotating net and the auxiliary rotating net. And a driving mechanism for driving the rotation, and when the main rotation net is at a predetermined rotation angle, the main rotation net and the auxiliary rotation net are configured so as not to wrap up and down due to the missing portion. (The invention of claim 1).

[0007] According to this, since the auxiliary rotating net is provided in the vicinity of the excitation port having a high electric field strength, heating is performed by supporting relatively small food on the auxiliary rotating net. It becomes possible to concentrate microwaves on the food for efficient heating. At this time, since the auxiliary rotating net is rotationally driven by the driving mechanism, the whole food can be uniformly heated. In the case of a relatively large food, it is a matter of course that the cooking can be performed while being supported by the main rotating net.

[0008] Since the auxiliary rotating net is provided so as to overlap with the rotation trajectory of the main rotating net vertically, the auxiliary rotating net hinders the food from being placed on the main rotating net. No additional large space is required for arranging the auxiliary rotating mesh, and when the main rotating mesh is at a predetermined rotation angle, the lacking portion causes the main rotating mesh and the auxiliary rotating mesh to wrap up and down. Since the main rotating net is stopped at its predetermined rotation angle, when placing food on the auxiliary rotating net,
The main rotating net does not disturb it.

In this case, the auxiliary rotating net can be provided near the front of the heating chamber (invention of claim 2), whereby the food can be taken in and out when the food is supported by the auxiliary rotating net. Etc. can be performed more easily.

[0010] Further, a food placing plate on which food is placed on the main rotating net is set detachably, and the upper surface of the auxiliary rotating net is a food placing surface. (The invention of claim 3). According to this,
Since the relatively small food can be placed directly on the upper surface of the auxiliary rotating net for heating and cooking, the auxiliary rotating net does not require any accessories such as a food placing plate. At this time, with respect to the main rotating net which is relatively large and does not easily come out of the flat surface, the food can be stably placed by setting the food placing dish, and the upper surface of the relatively small auxiliary rotating net can be removed. It is easy to make the surface flat.

The auxiliary rotating net is made of a conductive material, and has a rectangular opening having a length in a longitudinal direction of not less than の of the microwave wavelength and a transverse direction of less than １ ／ of the microwave wavelength. May be provided (the invention of claim 4). According to this, when the longitudinal direction of the opening intersects with the traveling direction of the microwave, the microwave is easily transmitted, and the microwave is transmitted when the traveling direction of the microwave coincides with the longitudinal direction of the opening. Since the waves are hardly transmitted, the electric field distribution in the heating chamber can be changed according to the change of the rotation angle of the auxiliary rotating net.

Similarly, the main rotating net is made of a conductive material, and has a rectangular opening having a length in the vertical direction which is equal to or more than の of the microwave wavelength and in the horizontal direction which is less than ４ of the microwave wavelength. A part may be provided (the invention of claim 5). According to this, the electric field distribution in the heating chamber can be changed according to the change in the rotation angle of the main rotating net.

Further, the main rotating net is formed in a grid shape having a vertical bar made of a conductive material and a horizontal bar crossing the vertical bar in a surrounding frame, and the vertical bar has a length longer than 1/2 of a microwave wavelength. The horizontal bar can be configured to be divided such that one bar has a length of less than half the microwave wavelength (the invention of claim 6). According to this, the wall current flows along the lattice portion by irradiating the microwave to the main rotating net, but the current is rectified and flows in one direction, which is the direction in which the vertical bar extends, The electric field distribution is changed by the flowing direction, that is, the rotation angle of the main rotating net. Further, it becomes difficult for the current to flow in the direction of the horizontal bar, which is a length dimension less than の of the microwave wavelength. Therefore, the change in the electric field distribution due to the change in the rotation angle of the main rotating net can be increased.

By the way, when the main rotating net and the auxiliary rotating net rotate, the state of reflection or transmission of the microwave changes according to the rotation angles, and the change causes a different electric field distribution (in the heating chamber) in the heating chamber. Standing wave mode)
Can be obtained. Here, if the rotation speeds of the main rotation net and the auxiliary rotation net are made different from each other (the invention of claim 7), the electric field distribution in the heating chamber always fluctuates over time, and the uniform heating of the food is achieved. Can be achieved.

Further, a detecting means for detecting whether or not the food is supported by the main rotating net is provided, and during cooking, when the food is supported by the main rotating net, both the main rotating net and the auxiliary rotating net are operated. When the food is not supported by the main rotating mesh, the auxiliary rotating mesh may be driven to rotate without rotating the main rotating mesh (the invention of claim 8). According to this, while heating the food on the main rotating net, it is possible to enjoy the advantage of the fluctuation of the electric field distribution in the heating chamber due to the rotation of the auxiliary rotating net. On the other hand, when the food is heated on the auxiliary rotating net, there is no possibility that the main rotating net hits the food.

Alternatively, when the auxiliary rotating net is cooked by heating,
It may be configured to stop at a specific rotation angle according to the type of food input or automatically determined by the user (the invention of claim 9). Here, as described above, different electric field distributions appear in the heating chamber due to the fluctuation of the rotation angle of the auxiliary rotating net,
For example, if the food is sake can, etc., the heating distribution at the top is small and the heating at the bottom is large to avoid uneven heating in the vertical direction. For shaped foods, there is an appropriate predetermined heating distribution depending on the type and size of each food, such as a uniform heating distribution in the plane direction. Therefore, by stopping the auxiliary rotating net at a specific rotation angle according to the type of food, a heating distribution can be obtained according to the type of food, and efficient heating can be performed.

When the main rotating net is stopped, it is desirable to position the main rotating net at a predetermined rotation angle (the tenth aspect of the present invention). As a result, before the start of heating cooking, the main rotating net and the auxiliary rotating net are always in a state in which they do not overlap with each other, so that the food can be supplemented without performing an operation such as moving the main rotating net. Heat cooking can be performed while being supported by a rotating net.

Further, by providing an angle detecting means for detecting the rotation angle of the main rotation net or the auxiliary rotation net, the main rotation net is stopped at a predetermined rotation angle, or the auxiliary rotation net is set to a specific rotation angle. In this case, if the angle detecting means is configured by using an optical sensor (the invention of claim 11) or by using a magnetic sensor (the invention of claim 12), The rotation angles of the rotating nets can be reliably detected, and the configuration for that can be simplified.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention (corresponding to claims 1, 2, 3, 4, 5, 6, 7, 8, 10, 11)
Will be described with reference to FIGS. 1 to 6. 1 to 4 schematically show the inside of a heating chamber of a microwave oven according to the present embodiment. Here, this microwave oven is configured by arranging a rectangular box-shaped oven cabinet 1 having an open front surface in an outer box (not shown), and the inside of the oven cabinet 1 is a heating chamber 2.

Although not shown, the front of the outer box has
A door for opening and closing the heating chamber 2 is provided, and located on the right side thereof, an operation for a user to select a food type (cooking menu), set a cooking time, give an instruction to start cooking, and the like. A panel 3 (shown only in FIG. 5) is provided. As shown in FIG. 5, an operation signal of the operation panel 3 is input to a control circuit 4 which is composed of a microcomputer or the like and functions as control means for controlling the entire microwave oven.

Although not shown in detail, a machine room is provided in the outer box at the right side of the oven chamber 1, and a micro chamber is provided in the machine room as shown in FIG. A magnetron 5 that oscillates waves, its driving circuit, a cooling fan device, the control circuit 4 and the like are provided. Further, in the present embodiment, a heater 6 (shown only in FIG. 5) for heating the food with a heater is provided on the ceiling of the heating chamber 2.

The microwave oscillated from the magnetron 5 passes through a waveguide (not shown), and in this case, an excitation port 7 (FIGS. 1 and 2) formed at the lower part of the right side wall of the oven chamber 1 in the front-rear direction. ) Is supplied into the heating chamber 2. Therefore, the microwave supply means is constituted by the magnetron 5 and the waveguide. Further, as shown in FIG.
Are also controlled by the control circuit 4.

FIG. 6 shows a bottom of the heating chamber 2.
As shown in FIG. 2, the main rotating net 8 for supporting the food Fb
Is provided. As shown in FIG. 3 and FIG. 4, the center of the main rotating net 8 is connected to a first rotating shaft 9 provided through the bottom surface of the heating chamber 2 (oven storage 1). The rotating shaft 9 is rotatably driven by an RT motor 10 as a driving mechanism provided on the outer bottom surface side of the heating chamber 2. The lower end of the first rotating shaft 9 is connected to a well-known capacitive weight sensor 11.

The main rotating net 8 is formed by enamelling the surface of a conductive material such as a steel plate. As shown in FIG. It is cut in a straight line, and is formed in a so-called oval shape, and is formed in a lattice shape integrally having a plurality of vertical bars 8b and a plurality of horizontal bars 8c orthogonal thereto in an annular peripheral frame 8a constituting the outer shape. ing. At this time, most of the vertical bars 8b extend continuously in the front-rear direction in FIG. 2, and are provided at equal pitches in the left-right direction in FIG. On the other hand, the horizontal bar 8c
Is almost always the wavelength λ of the microwave (about 122 m
m) is provided in a divided form so as to have a length dimension less than 1/2.

In this case, from the vertical bar 8b and the horizontal bar 8c, several rectangular openings 8d which are long in the front-rear direction in FIG.
“d” is provided so as to be shifted in the longitudinal direction by a half pitch and arranged in the left-right direction in the figure. Incidentally, the vertical dimension of the opening 8d is λ / 2 or more, for example, 64 mm,
The lateral dimension is less than λ / 4, for example, 30 mm.

As shown in FIGS. 1, 3 and 6, a food tray (turntable) 1 made of heat-resistant glass or ceramic is formed on the upper surface of the main rotating net 8 in the shape of a circular dish.
2 is set so as to be detachable, and a relatively large food Fb (for example, frozen pizza or the like) is placed on the food placing plate 12. Therefore, the main rotating net 8 supports the food Fb via the food placing plate 12. At this time, the weight of the food Fb (and the food placing tray 12) supported on the main rotating net 8 is detected by the weight sensor 11, and the signal is sent to the control circuit 4
To be entered.

As shown by an imaginary line in FIG. 2, the food placing plate 12 has a diameter slightly smaller than the longitudinal dimension in the heating chamber 2, and the main rotating net 8 has a slightly smaller dimension in the longitudinal direction (diameter dimension of a circle). Further, for example, when performing heater cooking such as toast, the food placing plate 12 is
And the main rotating net 8 is used as a grill net as it is.

An auxiliary rotating net 13 is provided on the right side of the main rotating net 8. The auxiliary rotating net 13 is formed by applying an enamel process to the surface of a conductive material such as a steel plate, and has an outer shape smaller than that of the main rotating net 8 as shown in FIGS. I have. The auxiliary rotating net 13 also has a lattice shape in which a plurality of vertical bars 13b and a plurality of horizontal bars 13c perpendicular thereto are integrally formed in an annular peripheral frame 13a, and FIG. The rectangular opening 13d long in the front-rear direction has a vertical dimension of λ / 2 or more, for example, 64 mm, and a horizontal dimension of λ.
It is less than / 4, for example, 30 mm.

As shown in FIGS. 3 and 4, the center of the auxiliary rotary net 13 is connected to a second rotary shaft 14 provided through the bottom of the heating chamber 2 (oven storage 1). The second rotating shaft 14 is rotatably driven by an auxiliary rotating net motor 15 as a driving mechanism provided on the outer bottom surface side of the heating chamber 2. At this time, the auxiliary rotating net 1
3 is provided at a position lower than the main rotating net 8. As shown in FIG. 4, the upper surface of the auxiliary rotating net 13 is
It is a flat and horizontal food mounting surface on which a relatively small food Fs (eg, a bowl of rice) is directly mounted.

As shown in FIGS. 1 and 2, the auxiliary rotating net 13 is located near the excitation port 7 and closer to the front of the heating chamber 2 (closer to the door). A part of the rotation trajectory of the main rotating net 8 wraps up and down. Further, when the main rotating net 8 is at a predetermined rotation angle whose longitudinal direction coincides with the front-rear direction as shown in FIG. 2 (this is called a stop rotation angle), The auxiliary rotating net 13 does not wrap up and down with the main rotating net 8 due to the notched portion, so to speak, so that the entire upper surface of the auxiliary rotating net 13 is opened upward when the food placing tray 12 is removed. .

The RT motor 10 and the auxiliary rotating mesh motor 15 are, for example, synchronous motors, and are controlled to be energized by the control circuit 4 as shown in FIG.
And the auxiliary rotating net 13 is rotated at a constant speed. At this time, as will be described later in detail,
In the case where the food Fb is placed on the top 2 and heating is performed, both the main rotating net 8 and the auxiliary rotating net 13 are simultaneously rotated.
Is located at a position lower than the main rotating net 8, the rotation thereof does not hinder cooking. At this time, the rotation speeds of the RT motor 10 and the auxiliary rotation net motor 15 are, for example, 5 rpm and 3.5 rpm, respectively, and the rotation speeds of the main rotation net 8 and the auxiliary rotation net 13 are different from each other. ing.

On the other hand, as will be described later, in the present embodiment, a relatively small food Fb can be placed on the auxiliary rotating net 13 for cooking.
At this time, the auxiliary rotating net 13 is rotated while the main rotating net 8 is stopped at the above-mentioned stop rotation angle. When the main rotating net 8 is not rotating, the main rotating net 8 is always stopped at the above-mentioned stop rotation angle. An angle detecting means is provided for detecting the rotation angle (rotation position) of the rotating net 8.

In this embodiment, as shown in FIGS. 2 and 6, the angle detecting means is provided with a light reflecting portion 16 at a predetermined position on the outer peripheral surface of the peripheral frame 8a of the main rotating net 8, and the heating chamber 2 A reflection type optical sensor 17 having a light projecting portion 17a and a light receiving portion 17b arranged side by side is provided on a wall portion on the far side of. The light reflecting portion 16 reflects the light emitted from the light projecting portion 17a at the light reflecting portion 16 and receives the light at the light receiving portion 17b when the main rotating net 8 rotates and comes to the stop rotation angle. Position.

Here, the main rotating net 8 is point-symmetrical with respect to the center of rotation (the same shape even when rotated by 180 degrees), so as shown in FIG. A similar light reflecting portion 16 is also provided at the position, and the optical sensor 17 can stop at the stop rotation angle regardless of which of the light reflecting portions 16 is detected. FIG.
As shown in the figure, the detection signal of the optical sensor 17 is input to the control circuit 4.
When the main rotating network 8 is stopped, the RT motor 10 is turned off when a detection signal from the optical sensor 17 is input.

The control circuit 4 controls the magnetron 5, the RT motor 10, the auxiliary rotating net motor 15 and the like based on an input signal from the operation panel 3 to execute heating cooking by the software configuration. I do
As will be described later, when starting the heating cooking, first, based on the detection of the weight sensor 11, whether the food Fb (and the food placing plate 12) is placed on the main rotating net 8 or not. It is designed to determine whether or not.
Therefore, the weight sensor 11 functions as a detecting unit.

When it is determined that the food Fb is supported by the main rotating net 8, the magnetron 5 is driven to start heating and cooking, and both the RT motor 10 and the auxiliary rotating net motor 15 are energized. Then, both the main rotating net 8 (the food placing tray 12) and the auxiliary rotating net 13 are driven to rotate. Further, for example, when the cooking time set by the user elapses, the magnetron 5, the RT motor 10, and the auxiliary rotating net motor 15 are stopped to end the cooking. At this time, the main rotation is performed as described above. Net 8
At the stop rotation angle.

On the other hand, when it is determined that the food Fb and the food placing plate 12 are not supported by the main rotating net 8, the magnetron 5 is driven and the auxiliary rotating net motor 15 is driven.
And the main rotating net 8 is not rotated, and only the auxiliary rotating net 13 is driven to rotate.

Next, the operation of the above configuration will be described. When the user wants to cook the food, the food is stored in the heating chamber 2. However, when the user wants to cook a relatively large food Fb, for example, for warming a frozen pizza, the user needs to cook the food. As shown in FIG. 3, in a state where the food placing plate 12 is set on the main rotating net 8, the food Fb is placed on the food placing plate 12. In this case, with respect to the main rotating net 8 which is relatively large and hardly comes out of a flat surface, the food Fb is stably set by setting the food placing plate 12.
Can be supported.

Then, the user operates the operation panel 3 to start cooking after setting, for example, a cooking time. Then, as described above, the weight sensor 11
It is determined that the food Fb is supported by the main rotating net 8 based on the detection of the control signal, and the control circuit 4 drives the magnetron 5 and simultaneously executes the RT motor 10 and the auxiliary rotating net motor 15.
And both the main rotating net 8 (food dish 12) and the auxiliary rotating net 13 are driven to rotate.

Thus, the microwave is supplied from the excitation port 7 into the heating chamber 2 to heat the food Fb. At this time, the auxiliary rotating net 13 newly provided in the heating chamber 2 is provided. Are provided so as to vertically overlap with the rotation locus of the main rotating net 8 (the food placing tray 12), so that the auxiliary rotating net 13
Does not require an extra large space to install
Compared with the conventional one not having the auxiliary rotating net 13, the capacity of the heating chamber 2 is increased or the food Fb (the food placing plate 12) is increased.
Does not move away from the excitation port 7. For this reason,
The heating efficiency of the food Fb does not decrease, and the auxiliary rotating net 13 does not hinder cooking.

At this time, the food Fb is placed on the food
2, the food Fb can be uniformly heated over the entire circumference thereof, and the main rotating net 8 made of a conductive material can be vertically bared with a length equal to or more than の of the microwave wavelength λ. 8b and a horizontal bar having a length of less than λ / 2, and a rectangular opening 8d having a length of λ / 2 or more and a width of less than λ / 4 is provided. As the rotation angle of the net 8 fluctuates, the state of reflection and transmission of microwaves and the state of flow of wall current change with time, so that the electric field distribution in the heating chamber 2 can be greatly changed, and the uniformity of the food Fb Heating can be achieved.

Then, along with this, the vertical direction is also λ /
2 or more, rectangular opening 13d whose lateral direction is less than λ / 4
Is also rotating, the microwaves are also disturbed by the auxiliary rotating net 13, and the electric field distribution in the heating chamber 2 can be changed. In addition, at this time, since the rotation speed of the auxiliary rotating net 13 is different from that of the main rotating net 8, the electric field distribution in the heating chamber 2 is not changed every time the main rotating net 8 is rotated but always fluctuates. Thus, the food Fb can be more uniformly heated. Furthermore, in the heating chamber 2,
Since the food placing plate 12 does not exist, the absorption of the radio wave by that amount is eliminated, and the heating efficiency is improved.

When, for example, the set cooking time has elapsed, the magnetron 5, the RT motor 10, and the auxiliary rotating net motor 15 are stopped to finish the cooking. At this time,
The magnetron 5 and the auxiliary rotating net motor 15 are immediately turned off, but the main rotating net 8 is continuously rotated until the optical sensor 17 detects the light reflecting portion 16. When any of the light reflecting portions 16 is detected, the RT motor 10 is turned off, and the main rotating net 8 is stopped at the stop rotation angle.

On the other hand, when the user wants to heat and cook relatively small food Fs, for example, for warming a bowl of rice, as shown in FIG. In the state where the food F is removed, the food F
s is placed directly. In this case, the auxiliary rotating net 1
3 is a flat and horizontal food loading surface, so that food F can be stably stored without using accessories such as a food loading plate.
s can be placed. At this time, since the auxiliary rotating net 13 is small, it is easy to make its upper surface a flat surface.

At this time, since the main rotating net 8 is stopped at the stop rotation angle as shown in FIG. 2, the entire upper part of the auxiliary rotating net 13 is open, and the food Fs is placed thereon. It doesn't get in the way. Furthermore, since the auxiliary rotating net 13 is located on the near side of the right side portion in the heating chamber 2, the work of putting in and out the food Fs can be performed more easily.

When the cooking is started, it is detected that the food Fb is not placed on the main rotating net 8 based on the weight sensor 11 as described above, and the control circuit 4 drives the magnetron 5. And the auxiliary rotating mesh motor 15
To drive the auxiliary rotating net 13 to rotate. Also, R
The T motor 10 is not energized, and the main rotating net 8 remains stopped at the stop rotation angle and does not hit the food Fs.

Thus, the food Fs on the auxiliary rotating net 13 is heated and cooked. Since the auxiliary rotating net 13 and thus the food Fs are arranged immediately near the excitation port 7, they are supplied. Microwaves are directly concentrated on the food Fs, and extremely efficient heating is performed. Further, at this time, the food Fs rotates, so that the entire circumference is uniformly heated, and further, the uniform heating by the change of the electric field distribution in the heating chamber 2 due to the rotation of the auxiliary rotating network 13 as described above. The effect can be expected.

As described above, according to this embodiment, the auxiliary rotating net 1 different from the main rotating net 8 is provided near the excitation port 7 in the heating chamber 2.
3 and a relatively small food F on the auxiliary rotating net 13 thereof.
Since the cooking can be performed with the s placed thereon, the relatively small food Fs can be efficiently heated, and the uneven heating at that time can be prevented to achieve uniform heating. Was.

In addition, the auxiliary rotating mesh 13 is provided so as to vertically wrap around the rotation locus of the main rotating mesh 8, and the main rotating mesh 8 is formed to have a shape in which a part of a circular outer periphery is deleted, and its stop rotation angle is reduced. Since the upper portion of the auxiliary rotating net 13 is opened at, the heating chamber 2 does not become large in size, and it is possible to prevent the heating efficiency of the relatively large food Fb from decreasing. is there.

In particular, in the present embodiment, the grids of the main rotating net 8 and the auxiliary rotating net 13 are devised, and the rotational speeds thereof are made different from each other, so that the food F
Further uniform heating of b and Fs can be achieved. Further, the auxiliary rotating net 13 is arranged near the front part, the food Fs is directly placed, and the weight sensor 11 automatically detects which of the rotating nets 8 and 13 is used. Therefore, the usability is improved for the user. Further, by using the optical sensor 17 to stop the main rotating net 8 at the stop rotation angle, it is possible to obtain several advantages such that the configuration can be simplified.

FIGS. 7 and 8 show other embodiments of the present invention, which are different from each other. Both of them have a structure of an angle detecting means for detecting the rotation angle (stop rotation angle) of the main rotating net 8. This is different from the above embodiment. That is, in the embodiment shown in FIG. 7, instead of the reflection type optical sensor 17 of the above embodiment,
A transmission-type optical sensor 21 in which a light projecting part 21a and a light receiving part 21b are arranged to face each other is provided at a corner on the left rear side of the heating chamber 2. On the other hand, at a predetermined position on the outer peripheral edge of the main rotating net 8, a protruding portion 22 that protrudes in the outer peripheral direction is provided.

In this configuration, the position where the projection 22 crosses the optical axis between the light projecting portion 21a and the light receiving portion 21b is set to be the stop rotation angle of the main rotating net 8,
Thus, the main rotating net 8 can be reliably stopped at the stop rotation angle by the detection of the optical sensor 21.

In the embodiment shown in FIG. 8, a magnet 23 is provided at a predetermined position on the outer peripheral edge of the main rotating net 8 and an angle detecting means for detecting that the magnet 23 has approached the inner wall of the heating chamber 2. A magnetic sensor 24 such as a Hall element is provided (corresponding to claim 12). Also in such a configuration, the angle at which the magnet 23 is detected by the magnetic sensor 24 is set to be the stop rotation angle of the main rotating net 8,
Accordingly, the detection of the magnetic sensor 24 allows the main rotating net 8 to be reliably stopped at the stop rotation angle.

In the above embodiment, the main rotating net 8
Even when a relatively large food Fb is supported on the (food placing plate 12) and is being cooked by heating, the auxiliary rotating net 13 is moved to uniform the electric field distribution by disturbing the radio waves in the heating chamber 2. It was configured to rotate. However, such uniformity of the electric field distribution may be such that, for example, when cooking sake cans, the upper portion becomes too hot due to convection, causing uneven heating in the vertical direction. However, this does not necessarily lead to an improvement in the heating efficiency. From the viewpoint of the heating efficiency, it may be more appropriate to heat the auxiliary rotating net 13 while stopping it at a specific rotation angle.

Therefore, although not shown, at the time of heating and cooking using the main rotating net 8 (the food placing tray 12), the auxiliary rotating net 13 is selected according to the food type input by the user or automatically determined by the user. May be stopped at a specific rotation angle to perform heating cooking (corresponding to claim 9). As a result, an appropriate heating distribution according to the food type can be obtained, and efficient heating can be performed.

In this case, the rotation angle of the auxiliary rotating net 13 for obtaining the optimum electric field distribution according to the kind of food is previously experimentally obtained, and when the food is, for example, "sake can", the lower part is heated strongly. The auxiliary rotating net 13 is stopped at a rotation angle A at which an electric field distribution capable of uniformly heating up and down is obtained,
When the food is, for example, "frozen pizza", the auxiliary rotating net 13 is stopped at a rotation angle B at which an electric field distribution that can be uniformly heated in a plane and has excellent heating efficiency is obtained. What is necessary is just to perform control of rotating the rotating net 13.

At this time, it is necessary to stop the auxiliary rotating net 13 at specific rotation angles A and B. However, as in the above-described embodiment, the auxiliary rotating net 13 is rotated by using an optical sensor or a magnetic sensor. Detecting the rotation angle, or the second rotation axis 1
The predetermined rotation angle may be detected using a microswitch or the like.

In addition, the present invention is not limited to each of the above-described embodiments, and for example, the following extensions and modifications are possible. That is, in the above embodiment, the weight sensor 11 detects whether or not the food Fb is supported on the main rotating net 8, but an optical sensor (position sensor) or the like may be used as the detecting means. Alternatively, the user may specify and input which rotating net is to be used. The cooking time may be automatically determined based on the weight detected by the weight sensor 11, or the cooking end point may be determined using a steam sensor or the like.

The outer shape of the main rotating net is not limited to the oval shape, but may be a shape obtained by cutting one side of a circle with a straight line, or a shape obtained by cutting off a part of a circle into a fan shape. It may be a rectangle or the like. Furthermore, the present invention can be implemented with appropriate modifications without departing from the gist, for example, various modifications can be made to the structure and dimensions of the grids inside the main rotating net and the auxiliary rotating net. .

[0060]

As apparent from the above description, according to the microwave oven of the present invention, the auxiliary rotating net for supporting relatively small foods located near the excitation port in the heating chamber is provided.
Since the main rotating mesh is provided so as to be wrapped up and down on the rotation locus of the main rotating mesh, and the main rotating mesh is formed in a shape in which a part of a circular outer periphery is deleted, the upper portion of the auxiliary rotating mesh is opened at a predetermined rotation angle. An excellent practical effect that it is possible to efficiently heat relatively small foods, but also to improve the uneven heating at that time, and to prevent the heating chamber from being enlarged. Is played.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a schematic perspective view of a heating chamber.

FIG. 2 is a plan view showing a state of a bottom in a heating chamber.

FIG. 3 is a front view of a heating chamber showing a state where relatively large food is cooked.

FIG. 4 is a front view of a heating chamber showing a state when relatively small foods are cooked.

FIG. 5 is a block diagram schematically showing an electrical configuration.

FIG. 6 is a perspective view of a main part in a heating chamber showing an optical sensor part.

FIG. 7 is a view corresponding to FIG. 6, showing another embodiment of the present invention.

FIG. 8 is a perspective view of a main part of a heating chamber showing a magnetic sensor part according to another embodiment of the present invention.

[Explanation of symbols]

In the drawing, 2 is a heating chamber, 4 is a control circuit, 5 is a magnetron (microwave supply means), 7 is an excitation port, 8 is a main rotating net,
8a and 13a are peripheral frames, 8b and 13b are vertical bars, 8c and 1
3c is a horizontal bar, 8d and 13d are openings, 10 is an RT motor (driving mechanism), 11 is a weight sensor (detection means), 12 is a food placing plate, 13 is an auxiliary rotating net, and 15 is an auxiliary rotating net motor. , 17, and 21 indicate optical sensors (angle detecting means), 24 indicates a magnetic sensor (angle detecting means), and Fb and Fs indicate foods.

Claims (12)

[Claims] 1. A heating chamber, a microwave supply means for supplying microwaves from an excitation port into the heating chamber, and a food provided at a bottom of the heating chamber in a shape in which the outer periphery of a circle is partially lost. And a smaller auxiliary than the main rotating net provided in the bottom of the heating chamber in the vicinity of the excitation port at the bottom portion so as to vertically overlap the rotation locus of the main rotating net. A rotating mesh, and a drive mechanism for rotating the main rotating mesh and the auxiliary rotating mesh, and when the main rotating mesh is at a predetermined rotation angle, the missing portion causes the main rotating mesh and the auxiliary rotating mesh to be rotated. Characterized in that the microwave oven is configured not to wrap up and down. 2. The microwave oven according to claim 1, wherein the auxiliary rotating net is provided near the front of the heating chamber. 3. A food placing plate on which food is placed is set detachably on the main rotating net, and the upper surface of the auxiliary rotating net is a food placing surface. The microwave oven according to claim 1 or 2, wherein: 4. The auxiliary rotating net is made of a conductive material,
4. The apparatus according to claim 1, wherein a longitudinal opening has a rectangular opening having a length dimension equal to or more than 1/2 of the microwave wavelength and a horizontal direction having a length dimension less than 1/4 of the microwave wavelength. The microwave oven described in Crab. 5. The main rotating net is formed of a conductive material, and has a rectangular opening having a length of at least half the microwave wavelength in the vertical direction and less than 横 of the microwave wavelength in the horizontal direction. The microwave oven according to any one of claims 1 to 4, wherein the microwave oven is provided. 6. The main rotating net has a lattice shape having a vertical bar made of a conductive material and a horizontal bar crossing the vertical bar in a surrounding frame, wherein the vertical bar has a length dimension equal to or more than の of a microwave wavelength. The microwave oven according to any one of claims 1 to 5, wherein the microwave oven has at least one horizontal bar, and one of the horizontal bars is divided so as to have a length of less than half the microwave wavelength. 7. The microwave oven according to claim 1, wherein the rotation speeds of the main rotation net and the auxiliary rotation net are different from each other. 8. A cooking machine comprising a detecting means for detecting whether or not food is supported by the main rotating net,
Based on the detection by the detection means, when the food is supported by the main rotating mesh, both the main rotating mesh and the auxiliary rotating mesh are driven to rotate. When the food is not supported by the main rotating mesh, the main rotating mesh is rotated. The microwave oven according to any one of claims 1 to 7, wherein the auxiliary rotation net is driven to rotate without rotating. 9. The method according to claim 1, wherein the auxiliary rotating net is stopped at a specific rotation angle corresponding to a food type input or automatically determined by a user during cooking. The microwave oven described in Crab. 10. The microwave oven according to claim 1, wherein the main rotating net is positioned at a predetermined rotation angle when stopped. 11. The apparatus according to claim 1, further comprising angle detecting means for detecting a rotation angle of the main rotating net or the auxiliary rotating net, and wherein the rotating angle detecting means is constituted by using an optical sensor. 11. The microwave oven according to any one of 10 above. 12. The apparatus according to claim 1, further comprising angle detection means for detecting a rotation angle of the main rotation net or the auxiliary rotation net, wherein the rotation angle detection means is constituted by using a magnetic sensor. 11. The microwave oven according to any one of 10 above.