JP2010255978A - Heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating cooker allowing easy works for easily optimizing a structure and a dimension of a choke means for suppressing leakage of microwaves radiated to a heating chamber from a gap of its door. <P>SOLUTION: A metal reflection member 24 is inserted into a choke groove 20 in a direction orthogonal to a circumferential direction of the choke groove 20 so that the microwave propagating through the choke groove 20 is circumferentially divided by the reflection member 24, which makes it possible to partially intercept the propagation in the circumferential direction of the choke groove 20, thereby allowing partial optimization, and after all, the whole optimization of the choke groove 20. Therefore, it is possible to easily build a choke structure capable of suppressing leakage of radio wave better than before. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cooking device including a choke unit that suppresses leakage of microwaves radiated into a heating chamber to the outside through a gap in a door.

  Conventionally, an annular choke groove has been provided in the part surrounding the window on the back of the door, and a periodic structure piece that delays the radio wave propagating in the circumferential direction in the choke groove has been arranged to suppress external radio wave leakage. (See Patent Document 1).

JP 59-37695 A

  By the way, the choke groove is configured as one choke groove by connecting the respective choke grooves corresponding to the four sides (upper side, right side, left side, lower side) of the door. I was adjusting. In other words, the adjustment of the structure dimensions of each of the four sides also affects all other sides, so it is not always optimized for each side, but it is not always optimal for each side (section). It was not designed in size, but was designed with a globally optimal solution that could be optimized when looking at all four sides. This occurs because radio waves propagating in the choke grooves corresponding to the respective sides are connected, and the work for obtaining the overall optimum solution is extremely troublesome.

  The present invention has been made in view of the above circumstances, and its purpose is to facilitate the work of simply optimizing the structural dimensions of the choke means for suppressing the microwave radiated into the heating chamber from leaking through the gap of the door. It is in providing the cooking device which becomes.

The heating cooker of the present invention is provided with a heating chamber provided in a main body and having an opening for taking in and out food, heating means for radiating microwaves to the heating chamber, and the opening at the front of the main body. An annular front plate provided so as to surround the door, the opening provided to be openable and closable, a door facing the front plate in a closed state, and a ring in a portion of the door facing the front plate A choke unit that suppresses the amount of radio wave leakage from the heating chamber to the outside, and a reflection unit that reflects radio waves propagating in the circumferential direction of the choke unit in the opposite direction,
The choke means is divided in the circumferential direction by the reflecting means.

  According to the present invention, since the microwave propagating through the choke means is reflected by the reflecting means in the opposite direction, the choke means can be separated by the reflecting means. As a result, the choke means can be partially optimized for each divided section, so that overall optimization can be easily achieved after all.

The perspective view which shows the backplate of the door in one Embodiment of this invention. The perspective view which expands and shows the corner | angular part of a backplate Perspective view of microwave oven Front view of the microwave oven shown with the door open Broken section showing the main part of the door Perspective view of choke groove schematically showing attachment of reflecting member Choke groove vertical section 6 equivalent diagram 7 equivalent diagram 6 equivalent diagram 2 equivalent diagram 7 equivalent diagram Diagram showing the correspondence between the width of the front plate and the amount of radio wave leakage

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a perspective view of the microwave oven, and FIG. 4 is a front view of the microwave oven shown with the door open. The main body 2 of the microwave oven 1 (corresponding to a heating cooker) is provided with a heating chamber 3, and food can be taken in and out of the heating chamber 3 through the opening 4. An annular front plate portion 5 is provided on the front surface of the main body 2 so as to surround the opening 4. A door 6 is supported at the lower part of the main body 2 by a hinge 7 so as to be pivotable in the vertical direction. When the door 6 is closed, the back side of the door 6 is slightly spaced from the front plate portion 5 (for example, 0.5 mm). To face each other.

  A machine room (not shown) is formed on the back of the main body 2, and a magnetron (corresponding to a heating means), a magnetron power supply device, a cooling fan device for cooling the magnetron and the power supply device, and the like are formed in the lower part of the machine room. It is arranged. The high frequency generated from the magnetron is radiated to the heating chamber 3 through the bottom plate 8 made of a dielectric such as a glass plate or a ceramic plate disposed at the bottom of the main body 2. In the space below the bottom plate 8 in the main body 2, a rotating antenna for reflecting and stirring the high frequency radiated from the magnetron is disposed. A lower heater composed of a sheath heater or the like is disposed so as to surround the rotating antenna, and an upper heater composed of a planar heater or the like is disposed in the space above the heating chamber 3 in the main body 2. . These upper and lower heaters function as oven heaters.

  A hot air generator (not shown) is provided on the back surface of the heating chamber 3. This hot air generator has a centrifugal fan and a hot air heater. A large number of air inlets 9 are formed on the inner wall of the heating chamber 3 so as to correspond to the center side of the fan, and a plurality of air outlets 10 are formed on both upper and lower sides of the air inlet 9. Yes. At the time of cooking in the oven, the hot air generator is driven, and the air in the heating chamber 3 is sucked into the hot air generator from the intake port 9 by the fan, heated by the hot air heater, and discharged from the upper and lower exhaust ports 10 to the heating chamber 3. . The heating chamber 3 is heated by such hot air circulation, and oven cooking is performed.

  A handle portion 11 is provided at the upper front portion of the door 6, and an operation panel 14 having a plurality of operation portions 12 and a display portion 13 is provided at the lower portion. The operation unit 12 is for setting a cooking mode, cooking time, cooking cabinet temperature (setting temperature), etc. for cooking. The display unit 13 is for displaying the selected cooking mode and cooking time.

  FIG. 5 is a broken sectional view showing a main part of the door 6. The door 6 includes a door main body 15 that forms a housing of the door 6, a metal back plate 16 integrated with the door main body 15, and an inner glass plate fixed to the back side of the window portion 16 a of the back plate 16. 17. A punching metal 18 fixed to the front side of the back plate 16 and formed with a number of holes of a size for blocking microwaves, and an outer glass plate 19 fixed to the front side of the door body 15. ing.

  FIG. 1 is a perspective view showing the back plate 16. An annular choke groove 20 (corresponding to choke means) is formed at the peripheral edge of the window 16a on the back side of the back plate 16. The choke groove 20 is a so-called slit choke groove, and includes a large number of periodic structure pieces 21 bent in a U-shape on the inner side. The periodic structure piece 21 adjusts the propagation characteristics of the radio waves in the circumferential direction of the choke groove 20 and suppresses the amount of radio wave leakage to the outside to be less than a specified value. The choke groove 20 is covered with a door cover 22 shown in FIG. 5, and a rectangular frame packing 23 is mounted between the back plate 16 and the door cover 22. The packing 23 hermetically blocks a gap between the door 6 and the front plate portion 5 when the door 6 is closed.

  Now, by adjusting the propagation characteristics of the radio waves in the circumferential direction of the choke groove 20 with the choke groove shape and the shape of the periodic structure piece 21, the amount of radio wave leakage to the outside is suppressed to a specified value or less. Since the choke grooves on the upper, lower, left and right sides are connected and the characteristics of the four sides influence each other, changing a part of the shape affects the entire circumference of the choke structure. For this reason, optimization cannot be performed for each side, and adjustment is performed while maintaining the overall balance. Is doing the right design. This occurs because radio waves are connected and propagated in the choke groove 20 corresponding to each side.

  Therefore, in the present embodiment, paying attention to this point, the reflection in the circumferential direction is suppressed by inserting the reflecting member 24 (corresponding to the reflecting means) into the choke groove 20. The reflecting member 24 reflects the radio wave propagating through the choke groove 20 to the opposite side, and divides the propagation path of the radio wave by inserting the choke groove 20 in a direction orthogonal to the circumferential direction of the choke groove 20. To function.

Here, the material, size, arrangement, etc. of the reflecting member 24 will be considered.
As the reflecting member 24, a conductive member that reflects radio waves is used, and is fixed to the choke groove 20 by welding, bonding, screwing, or the like. By disposing the reflecting member 24 in this way, most of the radio wave propagating in the circumferential direction through the choke groove 20 is reflected (slightly propagates, but the influence is reduced as a ratio. In this case, an independent choke space can be formed in the section delimited by the reflecting member 24. As a result, an optimum choke structure can be constructed in each section defined by the reflecting member 24, so that the overall choke performance can be improved.

  As the reflecting member 24, it is sufficient that at least the surface is a conductive member. Therefore, the reflecting member 24 may be formed of a metal-plated material or the like on the resin surface. However, in the product in which the oven function is added to the microwave oven 1 as in the present embodiment. Since the temperature of the choke structure portion may become high, it is desirable to form the reflecting member 24 of metal. From the viewpoint of durability, metal is desirable, and among metals, it is desirable to use a material having as low a surface resistance as possible, particularly an aluminum member having a small heat loss, such as an aluminum member, or stainless steel having high corrosion resistance. .

  On the other hand, when the size of the reflecting member 24 is larger than the width of the choke groove 20 as shown in FIGS. 8 and 9, the effect of suppressing the radio wave propagating in the circumferential direction is great, but the trade-off is As a relationship, the radio wave is easily leaked from the tip of the reflecting member 24 through the reflecting member itself. For these reasons, it is desirable that the size of the reflecting member 24 be smaller than the width of the choke groove 20. Further, since the electric field at the width of the opening of the choke groove 20 is strong, the size of the reflecting member 24 is as shown in FIG. 6 showing the choke groove 20 in cross section and FIG. Furthermore, it is desirable to make the width of the opening of the choke groove 20 smaller than the width of the opening while covering the width of the opening. Although the actual size of the reflecting member 24 is a matter of design, the desired performance can be exhibited by setting it to approximately the same width as the width of the opening of the choke groove 20.

On the other hand, in the choke structure, when the position where the periodic structure piece 21 is located and the position between the periodic structure pieces 21 are compared, the electric field component in the direction orthogonal to the circumferential direction of the position between the periodic structure pieces 21 is relatively small. For this reason, the reflection member 24 is inserted in a direction orthogonal to the circumferential direction, so that the electric field in the direction orthogonal to the circumferential direction of the reflection member 24 is theoretically zeroed to be reflected. For this reason, by inserting the reflecting member 24 at a position where the electric field in the direction orthogonal to the circumferential direction is small, the disturbance of the electric field in the reflecting member 24 can be suppressed, and the generation of leakage radio waves from the reflecting member 24 can be suppressed. it can. That is, the radio wave propagating through the choke groove 20 is not forcibly reflected but reflected at a position where the intensity of the radio wave is small, thereby minimizing the discontinuity of the radio wave in the choke groove 20 due to the insertion of the reflecting member 24. It is.
Moreover, since it is not necessary to change the shape of the periodic structure piece 21 itself by attaching the reflecting member 24 between the periodic structure pieces 21, the shape of the periodic structure piece 21 is not different in part by the reflecting member 24. , Local inconsistencies can be suppressed.

  By the way, the radio wave flowing into the choke structure from the heating chamber 3 is affected by the intensity distribution of the microwave in the heating chamber 3. Since the intensity distribution is mainly determined by the dimensions of the heating chamber 3, when the height dimension and the width dimension of the heating chamber 3 are different, the distribution of radio waves flowing into the left and right sides is different from the distribution of radio waves flowing into the upper and lower sides. It is common. In addition, since the choke structure has a recess for attaching to the hinge 7 and arm of the door 6 and a portion having a different shape, the characteristics of the radio wave propagating in the choke groove 20 are different for each side, and each is optimal. It is desirable to make it.

  Therefore, it is desirable to divide the circumferential direction of the choke groove 20 into a plurality of sections by the reflecting member 24. For this purpose, a plurality of reflecting members 24 are inserted. By dividing the choke groove 20 into a plurality of sections by the plurality of reflecting members 24, an optimum choke structure can be adjusted in each section.

  Further, when the choke groove 20 is divided into a plurality of sections in this way, the distribution of radio waves flowing into each side is different, so it is desirable that the choke structure for each side can be adjusted independently. Therefore, as shown in FIG. 2 in which the corner portion of the back plate 16 of the door 6 is enlarged, it is extremely effective to provide the reflecting member 24 at the four corner portions 20a that connect the four sides of the choke groove 20. In this case, the corner of the choke groove 20 is relatively far from the heating chamber 3, and the amount of microwaves directly flowing from the heating chamber 3 is relatively small, so that the radio waves in the heating chamber 3 travel through the reflecting member 24. Thus, the amount of leakage directly to the outside can be suppressed, which is also extremely suitable in this respect.

  By the way, in the choke groove 20, the width of the opening, particularly the electric field strength near the entrance of the opening of the choke groove 20 is strong. For this reason, if there is a gap space between the reflection member 24 and the inner wall surface 20b of the choke groove 20 in the portion where the reflection member 24 is inserted, particularly the opening, radio waves are transmitted through the gap space, and further, The reflected member 24 is in a floating state in the choke groove 20 and may rather be a factor that deteriorates the choke performance.

  Therefore, it is desirable that the reflecting member 24 and the inner wall surface 20b of the choke groove 20 are electrically connected (in terms of high frequency). On the other hand, since the electric field strength is relatively weak near the bottom surface of the choke groove 20, the effect of the gap is small, but it is desirable that there is no gap between the reflecting member 24 and the bottom surface of the choke groove 20. In this case, in order to further ensure electrical continuity between the reflecting member 24 and the inner wall surface 20b of the choke groove 20, a bent portion 24a is integrally formed on the reflecting member 24 as shown in FIG. It is desirable to provide a portion where both wrap by fixing along the inner wall surface 20b. By comprising in this way, the reflection member 24 and the inner wall surface 20b can be reliably conducted. In this case, in order to provide the reflecting member 24 at the corner portion 20a of the choke groove 20 as in this embodiment, the bent portion 24a is curved as shown in FIG. 11, and the curved inner wall surface 20b is circumferentially formed. Fix it in close contact with it.

  On the other hand, a door cover 22 (corresponding to a cover member) made of resin or the like is provided to protect the choke structure. Conventionally, the door cover 22 is held by the periodic structure piece 21 and the door body 15. However, the periodic structure piece 21 has a shape that tends to collapse due to its structural shape, and in the structure in which the door cover 22 is held by the periodic structure piece 21, there is a risk that force is applied to the periodic structure piece 21 during manufacturing. there were. For this reason, when force is applied to the periodic structure piece 21 to deform it, the choke performance deteriorates, so that management at the time of manufacture is troublesome. On the other hand, as shown schematically in FIG. 12, by holding the door cover 22 with a high-strength metal reflecting member 24, the force is not applied to the periodic structure piece 21. There is no troublesome manufacturing, the choke performance is stabilized, and the productivity is improved. In this case, since the reflecting member 24 is provided in a direction orthogonal to the mounting direction of the door cover, there is very little risk of deformation even when a force is applied by the door cover 22.

  From the above, the entire choke performance can be improved by inserting the reflecting member 24 between the periodic structure sides 21 at the corner 20a of the choke groove 20 as shown in FIG. In this case, the choke performance can be further improved by making the size of the reflecting member 24 smaller than the width of the opening of the choke groove 20 or fixing it in a state of being wrapped on the inner wall surface 20b of the choke groove 20. .

  Now, from experience, if the width of the front plate portion 5 on the main body 2 side (dimension in the direction orthogonal to the circumferential direction) is reduced, the choke performance deteriorates. Therefore, in the conventional structure, the width of the front plate portion 5 is reduced. It was difficult to set the value to ¼ or less of the microwave wavelength. However, in this embodiment, as a result of improving the choke performance as described above, even if the width of the front plate portion 5 is set to ¼ or less of the wavelength of the microwave, the desired choke performance can be exhibited. Can do.

  The inventor has obtained the correspondence between the width of the front plate portion 5 and the amount of radio wave leakage through experiments. FIG. 13 shows the correspondence between the width of the front plate 5 and the amount of radio wave leakage. From FIG. 13, according to this embodiment, even if the width of the front plate portion 5 is set to 30.5 mm or less, which is 1/4 of the wavelength of the microwave, the amount of radio wave leakage can be suppressed to an allowable value or less. I found out. Accordingly, the width of the front plate portion 5 necessary for the entire circumference of the heating chamber 3 can be reduced, so that the outer dimensions of the product can be reduced, and the installation property of the product can be improved.

  According to the present embodiment, by inserting the metal reflection member 24 in a direction orthogonal to the circumferential direction of the choke groove 20, the reflection member 24 transmits the radio wave propagating in the circumferential direction to the circumferential direction. Therefore, the radio wave propagating through the choke groove 20 can be partially blocked. Accordingly, since the choke groove 20 can be partially optimized, overall optimization can be easily achieved, and a choke structure capable of suppressing radio wave leakage can be easily constructed as compared with the prior art.

  In addition, as a result of improved choke performance, it is possible to construct a choke structure that is equivalent to the conventional space-saving configuration, so that it has been empirically orthogonal to the circumferential direction of the front plate portion facing the door. Although the width is required to be 1/4 or more of the wavelength λ of the microwave due to performance limitations, the width of the front plate portion 5 is reduced to λ / 4 or less as a result of the improved choke performance according to the present invention. It becomes possible.

The present invention is not limited to the above embodiment, and can be modified or expanded as follows.
The choke means is not limited to the choke groove, and the shape thereof is not limited as long as the structure attenuates the microwave.
The reflecting member may be formed integrally with the back plate of the door.
Instead of contacting the cover member with the reflecting member, a leg portion may be provided on the back side of the cover member so as to be separated from the periodic structure piece.

  In the drawings, 1 is a microwave oven (heating cooker), 2 is a main body, 3 is a heating chamber, 4 is a front plate portion, 6 is a door, 20 is a choke groove (choke means), 20a is a corner portion, and 20b is an inner wall surface. , 24 are reflecting members (reflecting means).

Claims (10)

A heating chamber provided in the main body and having an opening for taking in and out food;
Heating means for radiating microwaves to the heating chamber;
An annular front plate provided to surround the opening on the front surface of the main body;
The door is provided so as to be openable and closable, and is a door facing the front plate in a closed state,
Choke means that is provided in a ring shape at a portion facing the front plate portion in the door, and suppresses the amount of radio wave leakage from the heating chamber to the outside,
Reflecting means for reflecting radio waves propagating in the circumferential direction of the choke means in the opposite direction;
The cooking device according to claim 1, wherein the choke means is divided in the circumferential direction by the reflecting means.   The cooking device according to claim 1, wherein the reflecting means is made of metal. A plurality of the reflecting means are provided,
The cooking device according to claim 1 or 2, wherein the choke means is divided into a plurality of sections in the circumferential direction by the reflecting means. The choke means is configured by connecting a plurality of sides at corners,
The cooking device according to any one of claims 1 to 3, wherein the reflecting means is provided at the corner. The choke means is a choke groove;
The cooking device according to any one of claims 1 to 4, wherein the reflecting means is inserted into the choke groove. The choke means is a choke groove having an inner wall surface;
The cooking device according to any one of claims 1 to 5, wherein the reflecting means is fixed to the inner wall surface. The choke means is a choke groove having an inner wall surface;
The reflecting means is configured to have a bent portion bent in a direction orthogonal to the reflecting means,
The cooking device according to any one of claims 1 to 6, wherein the bent portion is fixed to the inner wall surface in a state of being closely contacted along a circumferential direction. The choke means is a choke groove having a plurality of periodic structure pieces arranged in the circumferential direction,
The cooking device according to any one of claims 1 to 7, wherein the reflecting means is provided between the periodic structure pieces. The choke means is a choke groove having a plurality of periodic structure pieces arranged in the circumferential direction,
A cover member for closing the choke groove;
The reflection means is provided in a state protruding from the periodic structure piece to the front plate portion side,
The cooking device according to any one of claims 1 to 8, wherein the cover member is held by the periodic structure piece.   The width orthogonal to the circumferential direction of the front plate portion is set to ¼ or less of the wavelength of the microwave radiated from the heating means. Cooking cooker.

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