JP2005019279A - High frequency heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency heating device in which microwave is emitted from a position shifted from the center of the ceiling wall so as not to hinder construction of the upper heater and which can make heating distribution uniform without having no rotation drive part. <P>SOLUTION: This is the high frequency heating device in which microwave emitted from a magnetron 33 is led to a heating chamber 31 through an opening 29 of a waveguide 28. The tube axis D of the waveguide 28 is shifted from the center G of the heating chamber and a shielding part 52 which shields the end part of the opening 29 on the side farther from the center G of the heating chamber is provided. Thereby, even if the tube axis D is shifted from the center G of the heating chamber, the direction of the microwave emitted from the waveguide 28 into the heating chamber 31 proceeds toward the opposite direction (center side G of the heating chamber) to the shielded side (farther side from the center G of the heating chamber) by the shielding part 52, and therefore the microwave can be emitted to the center of the heating chamber. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency heating apparatus that heats an object to be heated by microwaves, and uniformizes a heating distribution without being driven to rotate.
[0002]
[Prior art]
In a microwave oven, which is a typical high-frequency heating device, various configurations have been put into practical use for uniformizing the heating distribution by microwaves. For example, a configuration (turn table) for rotating a mounting table on which an object to be heated is placed, and a microwave radiation direction by rotating an antenna 3 that is coaxially coupled with a shaft portion 2 protruding into a waveguide 1 as shown in FIG. And the like (rotating antenna), and the structure of stirring the microwave by the rotation of metal blades in the heating chamber (rotating stirrer).
[0003]
In addition, as shown in FIG. 12, the effect of mounting the metal pieces 7a and 7b in the vicinity of the radiation antenna 6 of the magnetron 5 in the waveguide 4 and the effect of the turntable 8 are combined to achieve more uniformity. Yes (see, for example, Patent Document 1).
[0004]
Some examples using a turntable mention the shape of the opening connecting the waveguide and the heating chamber. For example, JP-A-8-124670 discloses many examples, which are described in FIGS. FIG. 13 shows a configuration in which the microwave oven is viewed from the front, and has a magnetron 9 and a waveguide 10 on the right wall surface side. FIG. 14 is a view as seen from the direction A in FIG. 13, and the opening 11 is formed in a rectangular shape. The waveguide generally transmits microwaves radiated from the antenna 12 of the magnetron 9 upward in FIGS. 13 and 14 by setting the width a to λ / 2 <a <λ with respect to the wavelength λ of the microwaves. (Generally λ = 120 mm and a = 80-100 mm). In this example, the opening 11 is formed at the upper end of the waveguide 10 to guide the microwave in the waveguide 10 to the heating chamber 13. As shown in FIG. 14, the most common opening often has the width a of the waveguide itself as the opening width. This is because the width of the opening is narrower than the width of the waveguide. This is thought to be due to the slight loss of microwaves at that part (when part of the width direction of the light is shielded). For reference, a general opening as shown in FIG. 14 has a symmetrical shape with respect to the center B in the width direction of the waveguide (referred to as a tube axis) and the end of the waveguide 10. It is characterized by being formed. Further, a general waveguide has two wide surfaces (H surface) and two narrow surfaces (E surface). As shown in FIGS. 13 and 14, the H surface is connected to a magnetron or a heating chamber wall surface. They are often integrated, and the opening is also formed on the H surface. FIG. 15 shows another example of the openings in which two openings 14 and 15 are formed on the end side of the waveguide and in front thereof. Further, in FIG. 16, there is one in which two openings 16 and 17 are formed at both ends of the waveguide 10 in the width direction. In the case of FIGS. 15 and 16, each side of the rectangular opening has a narrow side, but the other side has a length at least as long as the width of the waveguide 10, so that microwaves are sufficient. It is considered that transmission is possible in the heating chamber.
[0005]
[Patent Document 1]
JP-A-8-148273
[0006]
[Problems to be solved by the invention]
The conventional configuration has a rotation drive unit in any case, and parts such as a motor and a drive shaft are required, and power for driving is also required.
[0007]
In addition, rotating parts such as a turntable, rotating antenna, and rotating stirrer are arranged near the wall surface of the heating chamber and occupy a considerably large space. However, for products having not only a microwave oven function but also a heater heating function such as a recent microwave oven and toaster range, the rotation space is an obstacle, and it is difficult to arrange the heater at an optimal position. In particular, in the case of a radiant heater such as a tube heater used in an oven toaster, it is known that efficient heating can be achieved by bringing the upper heater and the lower heater as close as possible to the object to be heated. For example, when baking toast, it can be baked in a short time by placing a heater close to both the upper and lower surfaces of the pan. However, in the conventional configuration, the lower heater cannot be arranged in the center with the turntable or the rotating antenna arranged in the center of the bottom surface, and the upper heater is difficult to arrange in the rotating antenna or the rotating stirrer arranged in the center of the top surface. . In any case, not only the rotating parts but also the drive motor for transmitting the rotational force must be arranged in the vicinity of the rotating parts. Therefore, it is more difficult to arrange the heater.
[0008]
Moreover, in order to raise heater efficiency, the structure which makes the inside height low can be considered. This is because if the inside height is low, the distance between the upper heater and the food and the distance between the lower heater and the food can be reduced. However, when the inside height is lowered, it is difficult to make the heating distribution by the microwave uniform in a configuration without rotating parts. In general, most foods (objects to be heated) have a flat shape. Considering the case of heating flat foods, if microwaves are irradiated from the side wall or rear wall, the part on the side that irradiates microwaves However, the heating will proceed. On the other hand, when microwaves are irradiated from the bottom wall surface, the object to be heated and the bottom wall surface are so close that only the portion directly above the irradiated portion is heated. Therefore, in order to make the heating distribution uniform, it is always possible to know the ceiling wall surface that can maintain a certain distance from the object to be heated (especially from the center), and to irradiate uniform microwaves to make the distribution on the plane uniform. desirable.
[0009]
In order to solve these problems, the present invention is configured to irradiate microwaves from a position deviated from the center of the ceiling wall so as not to disturb the configuration of the upper heater, and has a uniform heating distribution even without a rotational drive unit. It aims at providing the high frequency heating device which can be made.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a high-frequency heating apparatus according to the present invention is a high-frequency heating apparatus that guides microwaves radiated from a magnetron to a heating chamber through an opening of a waveguide. It is deviated from the center of the heating chamber and has a shielding part that shields the end of the opening on the side far from the center of the heating chamber.
[0011]
Thereby, even if the tube axis is deviated from the center of the heating chamber, the direction of the microwave radiated from the waveguide to the heating chamber is the side shielded by the shielding portion (the side far from the center of the heating chamber). Since it goes to the opposite direction (center side of a heating chamber), a microwave can be radiated | emitted to the center of a heating chamber.
[0012]
Therefore, it is possible to provide a high-frequency heating device that is configured to irradiate microwaves from a position shifted from the center of the ceiling wall so as not to interfere with the configuration of the upper heater and that can make the heating distribution uniform even without a rotation drive unit. it can.
[0013]
The high-frequency heating device of the present invention guides the microwave radiated from the magnetron to the distribution adjustment chamber through the opening of the waveguide, and radiates the microwave from the periphery of the antenna provided in the distribution adjustment chamber into the heating chamber. In the heating apparatus, the tube axis of the waveguide is deviated from the center of the heating chamber, and a wide microwave passage space is formed on the center side of the heating chamber by the opening and the antenna.
[0014]
As a result, the non-uniform microwave transmitted from the waveguide opening into the distribution adjustment chamber is partially blocked by the antenna and radiated from the microwave passage space around the antenna into the heating chamber. The wave radiation direction can be changed, and uniform microwaves can be radiated into the heating chamber. In particular, even if the tube axis is deviated from the center of the heating chamber, the microwave can be radiated to the center of the heating chamber because it has a wide microwave passage space on the center side of the heating chamber.
[0015]
Therefore, it is possible to provide a high-frequency heating device that is configured to irradiate microwaves from a position shifted from the center of the ceiling wall so as not to interfere with the configuration of the upper heater and that can make the heating distribution uniform even without a rotation drive unit. it can.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The high frequency heating apparatus according to claim 1, wherein the microwave axis radiated from the magnetron is guided to the heating chamber through the opening of the waveguide, and the tube axis of the waveguide is shifted from the center of the heating chamber. And it is set as the structure which has the shielding part which shields the edge part of the said opening in the side far from the center of the said heating chamber.
[0017]
Thereby, even if the tube axis is deviated from the center of the heating chamber, the direction of the microwave radiated from the waveguide to the heating chamber is the side shielded by the shielding portion (the side far from the center of the heating chamber). Since it goes to the opposite direction (center side of a heating chamber), a microwave can be radiated | emitted to the center of a heating chamber.
[0018]
Therefore, it is possible to provide a high-frequency heating device that is configured to irradiate microwaves from a position shifted from the center of the ceiling wall so as not to interfere with the configuration of the upper heater and that can make the heating distribution uniform even without a rotation drive unit. it can.
[0019]
The high-frequency heating device according to claim 2 includes a distribution adjustment chamber between the waveguide and the heating chamber, and an opening and a shielding portion are formed on an upper surface of the distribution adjustment chamber, and the microwave incident from the opening is the distribution adjustment. It is configured to radiate into the heating chamber from around the antenna provided in the room.
[0020]
As a result, the non-uniform microwave transmitted from the waveguide opening into the distribution adjustment chamber is partially blocked by the antenna and radiated from the end of the distribution adjustment chamber around the antenna to the heating chamber. Thus, the microwave radiation direction can be changed, and uniform microwaves can be radiated into the heating chamber.
[0021]
The high frequency heating apparatus according to claim 3, wherein the microwave radiated from the magnetron is guided to the distribution adjusting chamber through the opening of the waveguide, and is radiated from the periphery of the antenna provided in the distribution adjusting chamber to the heating chamber. In the apparatus, the tube axis of the waveguide is deviated from the center of the heating chamber, and a wide microwave passage space is formed on the center side of the heating chamber by the opening and the antenna.
[0022]
As a result, the non-uniform microwave transmitted from the waveguide opening into the distribution adjustment chamber is partially blocked by the antenna and radiated from the microwave passage space around the antenna into the heating chamber. The wave radiation direction can be changed, and uniform microwaves can be radiated into the heating chamber. In particular, even if the tube axis is deviated from the center of the heating chamber, the microwave can be radiated to the center of the heating chamber because it has a wide microwave passage space on the center side of the heating chamber.
[0023]
Therefore, it is possible to provide a high-frequency heating device that is configured to irradiate microwaves from a position shifted from the center of the ceiling wall so as not to interfere with the configuration of the upper heater and that can make the heating distribution uniform even without a rotation drive unit. it can.
[0024]
The high-frequency heating device according to claim 4 is configured such that the opening is disposed on the center side of the heating chamber with respect to the waveguide.
[0025]
The high-frequency heating device according to claim 5 is configured such that the antenna is disposed on the side far from the center of the heating chamber with respect to the waveguide.
[0026]
Thus, a wide microwave passage space can be easily formed on the center side of the heating chamber.
[0027]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0028]
(Example 1)
1 to 4 show the configuration of the first embodiment of the present invention, FIG. 1 is a cross-sectional configuration diagram of the high-frequency heating device viewed from the front, FIG. 2 is a cross-sectional configuration diagram viewed from the right, and FIG. 4A and 4B are configuration diagrams of the antenna and the antenna holder that holds the antenna. FIG. 4A is a view from above, and FIG. 4B is a cross-sectional view taken along the line C-C in FIG.
[0029]
The left wall surface 18, the rear wall surface 19 and the right wall surface 20 are made of a common wall member, but this member is made of a material coated with fluorine in advance so that each wall surface is hard to get dirty and easy to wipe off. Yes. A horizontally long tube heater 22 (heating element) is attached to the lower center portion of the bottom wall surface 21 and the periphery is covered with a reflecting plate 23 to achieve uniform radiation heating from below. The ceiling wall surface 24 is provided with a tube heater 26 (a heating element) in a horizontally narrowed aperture 25 on the near side, and the shape of the aperture 25 makes uniform radiation heating from above. Since both the bottom wall surface 21 and the ceiling wall surface 24 are heated by the tube heaters 22 and 26, they are constituted by other members not coated with fluorine.
[0030]
In addition, a metal distribution adjusting chamber 27 is disposed behind the ceiling wall surface 24 and substantially in the center in the left-right direction. The microwave transmitted through the waveguide 28 is guided into the distribution adjustment chamber 27 from the opening 29 formed on the upper surface, passes through the periphery of the antenna 30 fixed in the distribution adjustment chamber 27, and is heated in the heating chamber 31. It is the structure radiated to. Here, the heating chamber 31 is formed by five wall surfaces (the left wall surface 18, the rear wall surface 19, the right wall surface 20, the bottom wall surface 21, and the ceiling wall surface 24), and is a space for heating an object to be heated (not shown). is there. The left wall surface 18, the rear wall surface 19, the right wall surface 20, the bottom wall surface 21, the ceiling wall surface 24, the distribution adjustment chamber 27, and the waveguide 28 forming the heating chamber 31 are electrically resistance welding (projection welding, spot welding) or caulking. Are joined mechanically and electrically conductively. The door 32 is configured to be able to open and close the heating chamber 31. The magnetron 33 generates microwaves from the radiation antenna 34, and the microwaves are transmitted from the center rear of the ceiling wall surface 24 into the heating chamber 31 through the waveguide 28, the opening 29, and the distribution adjustment chamber 27. In this configuration, an object to be heated (not shown) disposed in the heating chamber 31 is heated.
[0031]
In the present embodiment, while the magnetron 33 is disposed on the right wall surface 20 side, the microwave is introduced into the heating chamber 31 from the ceiling wall surface 24, so that the heating distribution by the microwave can be achieved even if the inside height is lowered. Can be made uniform to some extent. If the magnetron 33 is arranged on the right wall surface 20 side, the components can be arranged together on the right wall surface 20 side as in the conventional case, so that efficient component arrangement can be performed. At the same time, the magnetron 33 does not have to be disposed on the ceiling wall surface 24 side, so that the dead space on the ceiling wall surface 24 side can be reduced, and a compact configuration can be realized particularly in the vertical direction. As described above, even if the inside height is lowered, there is no harmful effect, and it is easy to shorten the baking time for toast and the like by improving the heater performance by reducing the inside height. In this embodiment, the upper and lower heaters are optimized by optimizing the shape of the aperture 25 for the tube heater 26 that is the upper heater and optimizing the reflector 23 for the tube heater 22 that is the lower heater. While improving the distribution, the height in the cabinet is reduced to about 145 mm to improve efficiency. (By the way, the inner width is 285 mm and the depth is 270 mm) And, for example, a toast (not shown) is placed on the top 35 mounted in the chamber and can be efficiently baked from both the upper and lower sides. Even with a commercial power supply (100V, 15A), the toast baking time can be shortened to about 3 minutes, similar to an oven toaster. Moreover, at the time of microwave heating, food may be placed on the top 35, or food may be placed after placing the plate 36 on the top 35 as shown in FIG.
[0032]
As shown in FIG. 4, the antenna 30 has a flat plate shape whose outer shape is processed into a circular shape having a diameter of 80 mm, and has notches 37 a and 37 b toward the center of the circle. The cuts 37a and 37b are both 17.5 mm wide and about 30 mm long, and the angle they make is about 160 degrees.
[0033]
On the other hand, the opening 29 is located slightly in front of the waveguide 28, and both the opening 29 and the antenna 30 are disposed in front of the distribution adjusting chamber 27. The opening 29 is about 68 mm in the vertical direction of FIG. 3 and about 80 mm in the horizontal direction of FIG.
[0034]
On the other hand, the waveguide 28 is disposed in the center of the distribution adjusting chamber 27 in the depth direction (vertical direction in FIG. 3) and to the right in the horizontal direction (horizontal direction in FIG. 3). The waveguide 28 has a width (vertical direction in FIG. 3) of about 80 mm, as in the case of a general microwave oven waveguide, and is located in front of and behind the depth (vertical direction in FIG. 3) 108 mm of the distribution adjusting chamber 27. There will be steps of 14 mm.
[0035]
Further, the length of the distribution adjusting chamber 27 in the left-right direction in FIG. 3 is such that the upper surface is about 103 mm and the lower surface is 143 mm and becomes wider toward the heating chamber. Further, the thickness of the distribution adjusting chamber 27 (vertical direction in FIGS. 1 and 2) is about 15 mm, and the antenna 30 is mounted at the approximate center in the thickness direction.
[0036]
The mounting method of the antenna 30 is a material with low high-frequency dielectric loss, and is electrically insulated from the waveguide 28 and the distribution adjustment chamber 27 and held, while the distribution adjustment chamber 27, the waveguide 28, the ceiling wall surface 24, and the like. Although it may be fixed to either one, the antenna holder 38 is particularly provided in the present embodiment. From FIG. 4, the three holes 39 of the antenna 30 are holes for catching the three claws A40 of the antenna holder 38, and have a small shape (10 mm × 3.5 mm) so that the microwave does not easily pass. The hole 41 of the antenna 30 is a hole for inserting the positioning pin 42 of the antenna holder 38, and the hole 43 is for inserting a stopper 44 formed of a protrusion of the antenna holder 38. Thus, in order to mount the antenna 30 to the antenna holder 38, first, the pin 42 is inserted into the hole 41, the claw A 40 is inserted into the hole 39, the antenna 30 is rotated counterclockwise, and the stopper 44 is inserted into the hole 43. Fit it in. The claw B45 is for fixing the antenna holder 38 to the distribution adjusting chamber 27, and is configured to be fitted into a hole 46 provided outside the waveguide 28 on the upper surface of the distribution adjusting chamber 27. Further, the hole 47 and the notch 48 of the antenna holder 38 have a high possibility that the electric field concentrates on the end faces 49 and 50 of the antenna 30, thereby avoiding local generation of high-frequency dielectric loss in the nearby antenna holder. The relief part which made the material escape is formed. Incidentally, it is desirable that the antenna holder 38 of this embodiment is made of a material such as PPS that is easy to process, has strength, and has low high-frequency dielectric loss. Of course, mica may be used if there is no problem in strength.
[0037]
In addition, a cover 51 is attached to the lower side of the distribution adjustment chamber 27 so as to be closed from the inside of the heating chamber 31.
[0038]
In addition, since the antenna 30 is located in the vicinity of the microwave radiated from the waveguide 28 through the opening 29, the antenna 30 should be made of a material with low high-frequency magnetic loss, such as a material obtained by performing aluminum plating on aluminum or an iron plate. Is desirable.
[0039]
Here, the opening 29 will be further described. In this embodiment, the upper surface of the distribution adjusting chamber 27 also serves as the H surface of the waveguide 28, and an opening 29 is formed on this surface. At this time, as is apparent from FIG. 3, the opening 29 is in front of the tube axis D of the waveguide 28. It can also be said that a shielding part 52 that shields a part of the opening is arranged behind the opening 29 (upper side in FIG. 3). In general, it seems that the microwave loss increases when such a shielding portion is provided. However, in the case of this example, there is no particular inconvenience, and heating efficiency is not lowered. There was no.
[0040]
On the other hand, it has been found that this shielding part has a great effect on the distribution of microwaves. A description will be added with reference to FIGS.
[0041]
5 and 6 show the simulation results of the electric field intensity distribution for the microwave radiated from the opening of the waveguide. FIG. 5 shows a conventional opening, and FIG. 5 has a shielding portion as in this embodiment. This is the case with an opening. 5 and 6 show (a) the electric field intensity 20 mm below the opening, (b) the electric field intensity 80 mm below the opening, and the lines in the figure are equal electric field intensity lines. 5 and 6, the equal electric field strength lines are coarser in (b) than in (a), so that the electric field strength is weak, that is, the electric field strength is weakened when moving away from the opening. . This is not a cavity resonator like a heating chamber, that is, a simulation based on the premise that it does not return by being reflected by the wall surface, and is considered to simply indicate the directivity of the microwave radiated from the opening. It is done. Therefore, the electric field strength decreases as the distance from the opening increases.
[0042]
First, in the case of the conventional opening 53 of FIG. 5, the opening 53 is symmetrical with respect to the tube axis E with respect to the microwave transmitted from the right side along the tube axis E in the waveguide 54, so that It can be easily imagined that the electric field strength distribution is symmetric downward. However, when attention is paid to the horizontal direction in the figure, the shape extends to the left.
[0043]
On the other hand, in the case of the present embodiment shown in FIG. 6, it is assumed that the opening 55 and the shielding portion 56 for forming the opening 55 are provided, and the shielding portion 56 is enlarged to make the effect of the shielding portion 56 easier to understand. For the microwave transmitted from the right side along the tube axis F in the waveguide 54, the opening 55 has an asymmetric shape with respect to the tube axis F, so that the electric field intensity distribution is asymmetrical upward and downward in the figure. Is easy to imagine. However, what is particularly worthy of attention here is that the shape of the electric field strength line extends downward. This means that by having the shielding part 56, the direction of the microwaves without the shielding part 56 is directed from the tube axis F.
[0044]
The reason for this is not yet clear, but I think that the configuration of the H-plane T-branch of the waveguide may be a hint. The H plane T branch will be described with reference to FIGS. Both are connected to the heating chamber 58 at the H surface of the waveguide 57, and the microwave incident wave 61 transmitted leftward in the waveguide 57 is guided into the heating chamber 58 through the openings 59 and 60. . In the case of FIG. 7, it is considered that the direction of the microwave 62 entering the storage is not directed downward, but is radiated slightly to the left by inheriting the direction of the incident wave 61. This may be considered to coincide with the fact that the equal electric field strength line extends to the left as shown in FIG. On the other hand, in the case of FIG. 8, the end of the waveguide 57 is extended to form a shield 63 at the end rather than the opening 60. The shield 63 forms a bag path 64 at the end of the waveguide 57, and a reflected wave 65 is generated in which a part of the incident wave 61 is reflected by the bag path 64. Therefore, the direction of the microwave 66 entering the chamber is a direction in which the incident wave 61 and the reflected wave 65 are combined, and is directed directly downward as shown in FIG. 8, for example. Here, in FIG. 8, the waveguide 57 and the opening 60 are branched into a T-shape (the waveguide 57 is a T horizontal bar and the opening 60 is a T vertical bar), and in particular, the H plane is branched. Therefore, it is called H-plane T-branch.
[0045]
Now, according to the H-plane T-branch, it is an important point that the terminal end forms a shield part with respect to the direction of the incident wave, but this embodiment is not. As apparent from FIG. 3, the shielding portion 52 is formed not on the end of the waveguide 28 but on the side, and is arranged in a direction orthogonal to the direction of the incident wave. Therefore, it is not possible to make a clear theorem at present, but as one point of view, if a part of the opening is shielded from the wall surrounding the opening, the direction of the microwave may be changed to the side opposite to the shielded side. . Therefore, in FIG. 3 and FIG. 6, a part of the opening is shielded by the shielding portions 52 and 56 from the E surface side on the upper side of the wall surface surrounding the openings 29 and 55, so that the side opposite to the shielded side is provided. The direction of the microwave can be changed at the bottom of the figure.
[0046]
In summary, in this embodiment, the tube axis D of the waveguide 28 is shifted backward (upward in FIG. 3) as viewed from the center of the heating chamber (G in FIG. 3), and from the center G of the heating chamber. The shielding part 52 that shields the end of the opening 29 is provided on the far side.
[0047]
Thereby, even if the tube axis D is deviated from the center G of the heating chamber, the direction of the microwave radiated from the waveguide 29 to the heating chamber 31 is changed to the side shielded by the shielding portion 52 (the center G of the heating chamber). Since it goes to the opposite direction (side G side of the heating chamber), the microwave can be emitted toward the center of the heating chamber.
[0048]
Therefore, there is provided a high-frequency heating device that is configured to irradiate microwaves from a position shifted from the center G of the ceiling wall surface 24 so as not to interfere with the configuration of the upper heater 26 and that can make the heating distribution uniform even without a rotation drive unit. can do.
[0049]
A distribution adjustment chamber 27 is provided between the waveguide 28 and the heating chamber 31, and an opening 29 and a shielding part 52 are formed on the upper surface of the distribution adjustment chamber 27. Microwaves incident from the opening 29 are contained in the distribution adjustment chamber 27. It is set as the structure radiated | emitted from the circumference | surroundings of the antenna 30 provided in the heating chamber 31.
[0050]
As a result, the non-uniform microwave transmitted from the opening 29 of the waveguide 28 into the distribution adjusting chamber 27 is partially blocked by the antenna 30 and the heating chamber 31 from the end of the distribution adjusting chamber 27 around the antenna 30. Therefore, the microwave radiation direction can be changed in the distribution adjusting chamber 27, and uniform microwaves can be radiated into the heating chamber 31.
[0051]
(Example 2)
FIG. 9 is a configuration diagram of the high-frequency heating device according to the second embodiment of the present invention as viewed from above.
[0052]
When the opening 29 and the antenna 67 are overlapped with each other, a hatched region 68 is formed, and this region is a space through which microwaves can pass. The antenna 67 has a notch 69 in the lower right of FIG. 9, thereby expanding the microwave passage space 68.
[0053]
As described above, in this embodiment, the tube axis D of the waveguide 28 is shifted from the center G of the heating chamber, and a wide microwave passing space 68 is formed on the center G side of the heating chamber by the opening 29 and the antenna 67. Yes.
[0054]
Thus, the non-uniform microwave transmitted from the opening 29 of the waveguide 28 into the distribution adjusting chamber 27 is partially blocked by the antenna 67 and radiated from the microwave passing space 68 around the antenna 67 into the heating chamber. Therefore, the microwave radiation direction can be changed in the distribution adjusting chamber 27, and uniform microwaves can be radiated into the heating chamber. In particular, even if the tube axis D is deviated from the center G of the heating chamber, since the microwave passage space 68 is wide on the center G side of the heating chamber as viewed from the tube axis D, the microwave is placed in the center of the heating chamber. Can radiate toward.
[0055]
Therefore, there is provided a high-frequency heating apparatus that is configured to irradiate microwaves from a position shifted from the center G of the ceiling wall so as not to hinder the configuration of the upper heater 26, and that can make the heating distribution uniform even without a rotation drive unit. be able to.
[0056]
Particularly, in this embodiment, the opening 29 is arranged on the center G side of the heating chamber with respect to the waveguide 28.
[0057]
Accordingly, a wide microwave passage space 68 can be easily formed on the center G side of the heating chamber.
[0058]
Example 3
FIG. 10 is a configuration diagram of the high-frequency heating device according to the third embodiment of the present invention as viewed from above.
[0059]
The opening 70 has a symmetric shape with respect to the tube axis D of the waveguide 28 and does not have a shielding part. However, the antenna 71 is arranged on the side farther from the center G of the heating chamber with respect to the tube axis D (upper side in FIG. 10), and the microwave passage space 72 is widely configured on the center G side of the heating chamber.
[0060]
As a result, the non-uniform microwave transmitted from the opening 70 of the waveguide 28 into the distribution adjusting chamber 27 is partially blocked by the antenna 71 and is widely disposed around the antenna 71, particularly on the heating chamber center G side. Since radiation is radiated from the microwave passage space 72 into the heating chamber, the direction of microwave radiation can be changed in the distribution adjustment chamber 27, and uniform microwaves can be radiated into the heating chamber. In particular, even if the tube axis D is deviated from the center G of the heating chamber, the microwave can be radiated to the center of the heating chamber because it has a wide microwave passage space on the center side of the heating chamber.
[0061]
Therefore, there is provided a high-frequency heating apparatus that is configured to irradiate microwaves from a position shifted from the center G of the ceiling wall so as not to hinder the configuration of the upper heater 26, and that can make the heating distribution uniform even without a rotation drive unit. be able to.
[0062]
In particular, the antenna 71 is arranged on the far side from the center G of the heating chamber with respect to the waveguide 28.
[0063]
Thereby, the wide microwave passage space 70 can be easily formed on the center G side of the heating chamber.
[0064]
In the above-described embodiment, the microwave passing space is shown around the antenna or in the cut portion. However, it is also possible to form the microwave passing space by providing a hole in the antenna.
[0065]
Moreover, although the antenna and the distribution adjustment chamber have been described as being parallel to the heating chamber, the antenna and the distribution adjustment chamber may be inclined with respect to the ceiling wall surface, for example. In particular, it is possible to widen the microwave passage space by inclining the antenna so that the center side of the heating chamber is lowered.
[0066]
Moreover, although the antenna has been described using only a flat plate, it is also conceivable that the microwave passage space is expanded or reduced by bending the edge, for example.
[0067]
Further, the microwave passage space is not formed only in the space when the opening and the antenna are viewed from above, but may be formed as a three-dimensional space. It can be considered as a space through which microwaves can pass.
[0068]
In the above embodiment, the opening formed in the connection surface between the distribution adjusting chamber and the heating chamber has been illustrated in a so-called fully open state without any particular description. However, the present invention is not limited to this. It is also possible to block a part by providing a shielding part. In particular, if the shielding portion is provided in the same direction as the shielding portion that covers the opening of the waveguide, it can be expected to further enhance the effect of changing the direction of the microwave.
[0069]
【The invention's effect】
As described above, the present invention relates to a high-frequency heating apparatus that guides microwaves radiated from a magnetron to a heating chamber through an opening of a waveguide, and the tube axis of the waveguide is deviated from the center of the heating chamber, It has the structure which has the shielding part which shields the edge part of the said opening in the side far from the center of a heating chamber.
[0070]
Thereby, even if the tube axis is deviated from the center of the heating chamber, the direction of the microwave radiated from the waveguide to the heating chamber is the side shielded by the shielding portion (the side far from the center of the heating chamber). Since it goes to the opposite direction (center side of a heating chamber), a microwave can be radiated | emitted to the center of a heating chamber.
[0071]
Therefore, it is possible to provide a high-frequency heating device that is configured to irradiate microwaves from a position shifted from the center of the ceiling wall so as not to interfere with the configuration of the upper heater, and that can make the heating distribution uniform even without rotational driving. .
[0072]
Further, the present invention is a high-frequency heating apparatus that guides microwaves radiated from a magnetron to a distribution adjustment chamber through an opening of a waveguide, and radiates the microwaves from around the antenna provided in the distribution adjustment chamber to the heating chamber. The tube axis of the waveguide is shifted from the center of the heating chamber, and a wide microwave passage space is formed on the center side of the heating chamber by the opening and the antenna.
[0073]
As a result, the non-uniform microwave transmitted from the waveguide opening into the distribution adjustment chamber is partially blocked by the antenna and radiated from the microwave passage space around the antenna into the heating chamber. The wave radiation direction can be changed, and uniform microwaves can be radiated into the heating chamber. In particular, even if the tube axis is deviated from the center of the heating chamber, the microwave can be radiated to the center of the heating chamber because it has a wide microwave passage space on the center side of the heating chamber.
[0074]
Therefore, it is possible to provide a high-frequency heating device that is configured to irradiate microwaves from a position shifted from the center of the ceiling wall so as not to interfere with the configuration of the upper heater and that can make the heating distribution uniform even without a rotation drive unit. it can.
[Brief description of the drawings]
FIG. 1 is a cross-sectional configuration diagram of a high-frequency heating device according to a first embodiment of the present invention viewed from the front.
FIG. 2 is a sectional configuration view from the right
FIG. 3 is a structural view seen from above.
Fig. 4 (a) Configuration of antenna and antenna holder
(B) The CC cross-section block diagram of Fig.4 (a) same as the above
FIG. 5 is an electric field intensity distribution diagram obtained by simulation with respect to a conventional example for comparison with Example 1 of the present invention.
(A) Electric field intensity distribution diagram 20 mm below the opening
(B) Electric field intensity distribution diagram 80 mm below the opening
FIG. 6 is an electric field intensity distribution diagram obtained by simulation with respect to Example 1 of the present invention.
(A) Electric field intensity distribution diagram 20 mm below the opening
(B) Electric field intensity distribution diagram 80 mm below the opening
FIG. 7 is a configuration diagram showing the direction of microwaves radiated from a waveguide to a heating chamber in the first embodiment of the present invention.
FIG. 8 is a configuration diagram showing the direction of the microwave radiated from the H-plane T-branch waveguide to the heating chamber in the first embodiment of the invention
FIG. 9 is a structural view of a high-frequency heating device according to a second embodiment of the present invention as viewed from above.
FIG. 10 is a configuration diagram of a high-frequency heating device according to a third embodiment of the present invention as viewed from above.
FIG. 11 is a cross-sectional configuration diagram of a conventional rotating antenna of a microwave oven.
FIG. 12 is a cross-sectional configuration diagram of another conventional microwave oven.
FIG. 13 is a cross-sectional configuration diagram of another conventional microwave oven.
FIG. 14 is a configuration diagram of the opening.
FIG. 15 is a configuration diagram of another opening.
FIG. 16 is a configuration diagram of another opening.
[Explanation of symbols]
27 Distribution adjustment room
28, 54 Waveguide
29, 55, 70 opening
30, 67, 71 Antenna
31 Heating chamber
33 Magnetron
52, 56 Shield
68, 72 Microwave passage space
D, F pipe shaft
G Heating chamber center

Claims (5)

In the high-frequency heating apparatus that guides the microwave radiated from the magnetron to the heating chamber through the opening of the waveguide, the tube axis of the waveguide is deviated from the center of the heating chamber and is far from the center of the heating chamber. A high-frequency heating apparatus having a configuration that includes a shielding portion that shields an end portion of the opening on the side. A distribution adjustment chamber is provided between the waveguide and the heating chamber, and an opening and a shielding part are formed on the upper surface of the distribution adjustment chamber, and the microwave incident from the opening is transmitted from the periphery of the antenna provided in the distribution adjustment chamber. The high-frequency heating device according to claim 1, wherein the high-frequency heating device is configured to radiate into the heating chamber. In the high-frequency heating apparatus for guiding the microwave radiated from the magnetron to the distribution adjustment chamber through the opening of the waveguide and radiating the microwave from the periphery of the antenna provided in the distribution adjustment chamber to the heating chamber, the tube of the waveguide A high-frequency heating apparatus having a configuration in which a shaft is deviated from the center of the heating chamber, and a wide microwave passing space is formed on the center side of the heating chamber by the opening and the antenna. The high-frequency heating device according to claim 3, wherein an opening is disposed on the center side of the heating chamber with respect to the waveguide. The high frequency heating apparatus according to claim 3, wherein an antenna is disposed on a side far from the center of the heating chamber with respect to the waveguide.

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