JP2013222672A - High frequency heating device - Google Patents

High frequency heating device Download PDF

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JP2013222672A
JP2013222672A JP2012095207A JP2012095207A JP2013222672A JP 2013222672 A JP2013222672 A JP 2013222672A JP 2012095207 A JP2012095207 A JP 2012095207A JP 2012095207 A JP2012095207 A JP 2012095207A JP 2013222672 A JP2013222672 A JP 2013222672A
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slit
center
waveguide
antenna
rotating antenna
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Tetsuo Kubota
哲男 窪田
Sachi Tanaka
佐知 田中
Ryoichi Kobayashi
良一 小林
Yasuaki Henmi
泰章 逸見
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Hitachi Appliances Inc
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Hitachi Appliances Inc
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Abstract

PROBLEM TO BE SOLVED: To provide a high frequency heating device with a rotary antenna that can realize more efficient heating.SOLUTION: A high frequency heating device comprises: a heated object location plate provided in a heating chamber; a high frequency supplying chamber provided below the heated object location plate; a magnetron; a waveguide for mounting the magnetron; a coupling hole for radiating microwave energy introduced by the waveguide; an inner conductor penetrating through the coupling hole; a parabolic antenna-like and metal disc-like rotary antenna almost parallely coupled to one end of the inner conductor whose heating chamber side is projected; a dielectric shaft coupled in the waveguide of the inner conductor; and a drive section for rotary driving the dielectric shaft. A first slit and a second slit are provided on the rotary antenna. When a segment connecting a center of the first slit and a rotary antenna center 0 is designated as Land a segment connecting a center of the second slit and the rotary antenna center 0 is designated as L, the segment Land the segment Lare almost linear, and a length difference (L-L) of the segment Land the segment Lis about 1/2 of a wavelength of microwaves.

Description

本発明は、回転アンテナを用いてマイクロ波エネルギーを加熱室内に放射し、食品などを高周波加熱する高周波加熱装置に関するものである。   The present invention relates to a high-frequency heating apparatus that radiates microwave energy into a heating chamber using a rotating antenna and heats food or the like at high frequency.

従来の高周波加熱装置として、加熱室の底面に固着された誘電体からなる載置棚を備え、加熱室天井中央部に設けた導波管の励振口と導波管の励振口部分に回転導波管を備え、導波管により導かれるマイクロ波エネルギーを回転導波管に導き回転導波管に設けられた回転導波管軸方向に垂直なスリットと平行なスリットよりマイクロ波を加熱室内に放射し、載置棚に載置された食品などを高周波加熱するものがある(特許文献1、特に第1図)。   As a conventional high-frequency heating device, a mounting shelf made of a dielectric material fixed to the bottom surface of the heating chamber is provided, and the waveguide excitation port provided in the center of the heating chamber ceiling and the waveguide excitation port portion are rotated and guided. A microwave tube is provided, the microwave energy guided by the waveguide is guided to the rotating waveguide, and the microwave is introduced into the heating chamber by a slit parallel to the axis of the rotating waveguide provided in the rotating waveguide and parallel to the slit. There is one that radiates and heats the food placed on the placing shelf at high frequency (Patent Document 1, especially FIG. 1).

特開昭61−294788号公報Japanese Patent Laid-Open No. 61-294788

特許文献1に記載された高周波加熱装置では、回転導波管の構造が一般的な導波管のように矩形型構造でなく加熱室天井壁面と対向する回転導波管の長辺面が除去され、しかも、加熱室天井壁面間と隙間を持たせた構造となっている。このため、マグネトロンからのマイクロ波の大部分は導波管の励振口に近い上記加熱室天井壁面と回転導波管の隙間から四方八方に放射され、導波管を伝送されたほんの一部のみが回転導波管に結合される。   In the high-frequency heating device described in Patent Document 1, the structure of the rotating waveguide is not a rectangular structure like a general waveguide, but the long side surface of the rotating waveguide facing the heating chamber ceiling wall surface is removed. In addition, the heating chamber has a structure with a gap between the ceiling wall surfaces. For this reason, most of the microwaves from the magnetron are radiated in all directions from the space between the heating chamber ceiling wall and the rotating waveguide near the excitation port of the waveguide, and only a small part transmitted through the waveguide. Are coupled to the rotating waveguide.

また、一部のマイクロ波が回転導波管に結合されて回転導波管の管軸方向に伝送されていたとしても、マイクロ波の進行方向に垂直な平面で水平方向に電界成分を一つもち、垂直方向には電界成分もたない、磁界成分のみがマイクロ波進行方向に存在するマイクロ波の伝送姿態であるTE10モードをもつ回転導波管において、回転導波管の食品と対向して設けられている長辺管壁面中心上で、回転導波管の管軸方向に平行にスリットを設けた従来技術では、上記スリットの幅Wが長さLに比べて十分小さい。このため、回転導波管の壁面を管軸方向に流れる高周波電流を殆ど切ることがないので、このスリットからはマイクロ波放射されない。   Moreover, even if some microwaves are coupled to the rotating waveguide and transmitted in the tube axis direction of the rotating waveguide, one electric field component is generated in the horizontal direction on a plane perpendicular to the traveling direction of the microwave. In a rotating waveguide having a TE10 mode, which is a transmission state of microwaves that has no electric field component in the vertical direction and only the magnetic field component exists in the microwave traveling direction, it faces the food of the rotating waveguide. In the prior art in which a slit is provided parallel to the tube axis direction of the rotating waveguide on the center of the long side tube wall surface provided, the width W of the slit is sufficiently smaller than the length L. For this reason, since the high-frequency current flowing in the tube axis direction through the wall surface of the rotating waveguide is hardly cut, microwaves are not emitted from the slit.

したがって、回転導波管にわずかに結合されたマイクロ波は、上記回転導波管の管軸方向と垂直に設け、管軸方向に流れる高周波電流を切ることができるもう一つのスリットからのみ食品に放射されるだけである。   Therefore, the microwave slightly coupled to the rotating waveguide is provided perpendicularly to the tube axis direction of the rotating waveguide and is applied to the food only from another slit that can cut the high-frequency current flowing in the tube axis direction. It is only radiated.

このため、食品が効率的に加熱されず、また、回転導波管を回転させるための回転軸は、上記回転導波管の一端に設置されているので回転時にぶれを生じ、加熱室天井面と接触してスパークを発生したり、衝突音、こすれ音が発生したりするなどの問題があった。   For this reason, the food is not efficiently heated, and the rotating shaft for rotating the rotating waveguide is installed at one end of the rotating waveguide, so that it is shaken during rotation, and the heating chamber ceiling surface There were problems such as sparks coming into contact with the device, collision noise, and rubbing noise.

上記課題を解決するため、本発明の高周波加熱装置では、被加熱物を収容する加熱室と、該加熱室の底面に設けられた誘電体からなる被加熱物載置板と、該被加熱物載置板の下方で前記加熱室の底面中央部に設けられた高周波供給室と、マイクロ波エネルギーを発生するマグネトロンと、該マグネトロンを取り付ける導波管と、該導波管に導かれたマイクロ波エネルギーを前記高周波供給室に放射するために高周波供給室底面略中央部に設けられた結合穴と、該結合穴を貫通して前記高周波供給室内へ略垂直に臨んで設けられた内導体と、該内導体の一端の前記高周波供給室内に略水平に連結された金属製円板の回転アンテナと、前記内導体の前記導波管内で連結された誘電体軸と、該誘電体軸を回転駆動する駆動部を備え、前記回転アンテナには、第1のスリットと第2のスリットが設けられており、前記第1のスリットの中心と回転アンテナ中心0を結ぶ線分L1、前記第2のスリット中心と回転アンテナ中心0を結ぶ線分L2としたとき、線分L1と線分L2が略直行し、線分L1と線分L2の長さの差(L2−L1)が前記マグネトロンから供給されるマイクロ波の波長の約1/2であることとした。 In order to solve the above-described problem, in the high-frequency heating device of the present invention, a heating chamber for storing a heated object, a heated object mounting plate made of a dielectric provided on the bottom surface of the heated chamber, and the heated object A high-frequency supply chamber provided at the bottom center of the heating chamber below the mounting plate, a magnetron for generating microwave energy, a waveguide for mounting the magnetron, and a microwave guided to the waveguide A coupling hole provided in a substantially central portion of the bottom surface of the high-frequency supply chamber for radiating energy to the high-frequency supply chamber; an inner conductor provided through the coupling hole and facing the high-frequency supply chamber substantially vertically; A rotating antenna of a metal disk connected substantially horizontally in the high-frequency supply chamber at one end of the inner conductor, a dielectric shaft connected in the waveguide of the inner conductor, and rotationally driving the dielectric shaft A drive unit for rotating the rotating antenna. The, a first slit and a second slit provided, connecting the line segment L 1, the rotation center of the antenna 0 and the second slit center connecting the rotational center of the antenna 0 and the center of the first slit When the line segment is L 2 , the line segment L 1 and the line segment L 2 are substantially perpendicular, and the length difference (L 2 −L 1 ) between the line segment L 1 and the line segment L 2 is supplied from the magnetron. It was about 1/2 of the wavelength of the microwave.

本発明の高周波加熱装置を用いると、結合穴と内導体で同軸モードで結合されたマイクロ波エネルギーは、回転アンテナと高周波供給室底面で挟まれた空間を回転アンテナの中心から外周囲に向かって放射状に球面波として伝送され、効率的に食品を加熱することができる。また、第1のスリットでの電界ベクトルと第2のスリットでの電界ベクトルが逆相であっても電界強度が弱まったり、打ち消されることはなく被加熱物の加熱が促進される。さらに、回転アンテナは円板で円板の中心0に回転軸があるために、ぶれが緩和され安定した回転を維持することができ、加熱室天井面と接触してスパークの発生、衝突音、こすれ音が発生するなどの問題がない。   When the high-frequency heating device of the present invention is used, the microwave energy coupled in the coaxial mode by the coupling hole and the inner conductor passes through the space sandwiched between the rotating antenna and the bottom surface of the high-frequency supply chamber from the center of the rotating antenna toward the outer periphery. It is transmitted as a spherical wave radially and can efficiently heat the food. Further, even if the electric field vector at the first slit and the electric field vector at the second slit are in opposite phases, the electric field strength is not weakened or canceled, and the heating of the object to be heated is promoted. Furthermore, since the rotating antenna is a disk and has a rotating shaft at the center 0 of the disk, the vibration is reduced and stable rotation can be maintained. There is no problem of rubbing noise.

実施例1の高周波加熱装置の要部縦断面図である。It is a principal part longitudinal cross-sectional view of the high frequency heating apparatus of Example 1. 実施例1の回転アンテナの平面図および断面図である。It is the top view and sectional drawing of the rotation antenna of Example 1. 実施例1の回転アンテナの加熱特性の改善効果を示す解析結果図である。It is an analysis result figure which shows the improvement effect of the heating characteristic of the rotating antenna of Example 1. 実施例2の回転アンテナの平面図および側面図である。It is the top view and side view of a rotation antenna of Example 2. 実施例3の回転アンテナの平面図および側面図である。It is the top view and side view of a rotation antenna of Example 3.

以下、本発明の実施例を図1〜図5を参照して説明する。   Embodiments of the present invention will be described below with reference to FIGS.

図1は実施例1の高周波加熱装置の要部縦断面図で、1は被加熱物を収容する加熱室である。2は被加熱物載置板で、加熱室1の底面に固着され誘電体からなり、例えば結晶化ガラスで構成され被加熱物を載置する。3は高周波供給室で、被加熱物載置板2の下方で前記加熱室1の底面略中央部に設けられている。4はマイクロ波エネルギーを発生させるマグネトロンである。5は導波管で、一端にはマグネトロン4が取り付けられており、他端はマグネトロン4から発生したマイクロ波エネルギーを高周波供給室3に導くように該高周波供給室3に連通されている。6は結合穴で、高周波供給室3の底面略中央部に設けられ、導波管5を高周波供給室3に連通させる。マグネトロン4で発生したマイクロ波エネルギーは結合穴6を通して高周波供給室3に放射される。7は結合穴6内に設けられる内導体で、結合穴6を貫通して設けられ、導波管5から高周波供給室3内へ略垂直に臨んで設けられている。8は加熱室1側を凸にしたパラボラアンテナ状の回転アンテナで、本実施例ではアルミニウム等の良導電性金属製の円板で構成され、中心部を内導体7の一端に略水平に連結されている。9は誘電体軸で、内導体7と導波管5内で連結され、誘電体軸9の他端は導波管5に開けられた穴10を通して導波管5の下部に設けられた駆動部11に連結され、回転アンテナ8は駆動部11により回転自在となっている。12は被加熱物載置板2に載置された被加熱物である。そして、マグネトロン4で発生したマイクロ波エネルギーは導波管5に導かれ、結合穴6を貫通する内導体7との同軸モード結合により高周波供給室3に伝播され、さらに、高周波供給室3内では伝播されたマイクロ波エネルギーは回転アンテナ8に伝播され、回転アンテナ8から被加熱物載置板2を通して加熱室1内に放射される。   FIG. 1 is a longitudinal sectional view of an essential part of the high-frequency heating apparatus according to the first embodiment. Reference numeral 1 denotes a heating chamber for accommodating an object to be heated. Reference numeral 2 denotes a heated object placing plate, which is fixed to the bottom surface of the heating chamber 1 and made of a dielectric, and is made of, for example, crystallized glass and places the heated object. Reference numeral 3 denotes a high-frequency supply chamber, which is provided at a substantially central portion of the bottom surface of the heating chamber 1 below the heated object placing plate 2. A magnetron 4 generates microwave energy. Reference numeral 5 denotes a waveguide. A magnetron 4 is attached to one end, and the other end communicates with the high-frequency supply chamber 3 so as to guide the microwave energy generated from the magnetron 4 to the high-frequency supply chamber 3. Reference numeral 6 denotes a coupling hole, which is provided at a substantially central portion of the bottom surface of the high-frequency supply chamber 3 and allows the waveguide 5 to communicate with the high-frequency supply chamber 3. Microwave energy generated by the magnetron 4 is radiated to the high-frequency supply chamber 3 through the coupling hole 6. Reference numeral 7 denotes an inner conductor provided in the coupling hole 6, which is provided so as to penetrate the coupling hole 6, and is provided to face the high-frequency supply chamber 3 from the waveguide 5 substantially vertically. Reference numeral 8 denotes a parabolic antenna-shaped rotating antenna having a convex heating chamber 1 side. In this embodiment, the rotating antenna is composed of a disk made of a highly conductive metal such as aluminum, and the central portion is connected to one end of the inner conductor 7 substantially horizontally. Has been. A dielectric shaft 9 is connected to the inner conductor 7 and the waveguide 5, and the other end of the dielectric shaft 9 is provided at the lower portion of the waveguide 5 through a hole 10 formed in the waveguide 5. The rotating antenna 8 is connected to the unit 11 and is freely rotatable by the driving unit 11. Reference numeral 12 denotes a heated object placed on the heated object placing plate 2. Then, the microwave energy generated in the magnetron 4 is guided to the waveguide 5 and propagated to the high frequency supply chamber 3 by coaxial mode coupling with the inner conductor 7 penetrating the coupling hole 6, and in the high frequency supply chamber 3. The propagated microwave energy is propagated to the rotating antenna 8 and radiated from the rotating antenna 8 through the heated object mounting plate 2 into the heating chamber 1.

図2は実施例1の回転アンテナ8の平面図および断面図で、本実施例では直径220mmの円板で構成されている。この回転アンテナ8上に、スリット幅WA、スリット長さLAのスリットA(8a)と、スリット幅WB、スリット長さLBのスリットB(8b)を設ける。スリットA(8a)、スリットB(8b)の各々は長軸が回転アンテナ8の直径と垂直になるように設けられている。ここで、スリットAの中心と回転アンテナ8の中心0を結ぶ線分をL1とし、スリットBの中心と回転アンテナ8の中心0を結ぶ線分をL2とする。そして、2本の線分L1とL2が略直行し、L1とL2の長さの差(L2−L1)がマイクロ波の波長約120mmの1/2に保たれるようにスリットA(8a)とスリットB(8b)を配置する。図2に示す本実施例では、L1=15〜20mm、L2=75〜80mmに設定し、(L2−L1)=55〜65mm(好ましくは60mm)とした。つまり、(L2−L1)がマイクロ波の波長λ120mmの46〜54%程度となるように、両スリットを配置した。また、スリット長さLA、LBを61mmとし、スリット幅WA、WBを10mmとした。なお、スリット幅WA、WBは同一の幅でもよく、異なった幅でもよい。実用上スリット幅WA、WBは、スリットにマイクロ波が結合された時の耐スパーク性などを考慮してWA、WB=5〜15mmに選んでいる。なお、本実施例では、回転アンテナ8の高さを10mmとしているが、5〜10mmの範囲であれば、任意の高さを選択してよい。 FIG. 2 is a plan view and a cross-sectional view of the rotating antenna 8 according to the first embodiment. In this embodiment, the rotating antenna 8 is formed of a disk having a diameter of 220 mm. On the rotating antenna 8, the slit width W A, the slit length L A of the slit A (8a), the slit width W B, the slits B (8b) of the slit length L B. Each of the slit A (8a) and the slit B (8b) is provided so that the long axis is perpendicular to the diameter of the rotating antenna 8. Here, the line segment connecting the center 0 of the center of the slit A rotating antenna 8 and L 1, a line segment connecting the center 0 of the center of the slit B rotating antenna 8 and L 2. Then, the two line segments L 1 and L 2 are substantially orthogonal, and the difference in length between L 1 and L 2 (L 2 −L 1 ) is maintained at ½ of the microwave wavelength of about 120 mm. Slit A (8a) and slit B (8b). In this embodiment shown in FIG. 2, L 1 = 15 to 20 mm, L 2 = 75 to 80 mm, and (L 2 −L 1 ) = 55 to 65 mm (preferably 60 mm). That is, both slits were arranged so that (L 2 −L 1 ) was about 46 to 54% of the microwave wavelength λ120 mm. Further, slit length L A, the L B and 61 mm, the slit width W A, a W B was 10 mm. The slit width W A, W B may be the same width, may be different widths. Practically, the slit widths W A and W B are selected to be W A and W B = 5 to 15 mm in consideration of spark resistance when microwaves are coupled to the slit. In the present embodiment, the height of the rotating antenna 8 is 10 mm, but an arbitrary height may be selected within the range of 5 to 10 mm.

次に、以上の構成による作用を説明する。   Next, the operation of the above configuration will be described.

実施例1の回転アンテナ8では、結合穴6と内導体7で同軸モード結合されたマイクロ波エネルギーは、回転アンテナ8と高周波供給室3底面で挟まれ空間を回転アンテナ8の中心から回転アンテナ8外周囲に向かって放射状に球面波として伝送される。本実施例では、2線分の長さの差(L2−L1)を供給されるマイクロ波の波長のおよそ1/2に選んでいるので、スリットA(8a)で電界強度が最大で結合した場合に、1/2波長離れたスリットB(8b)では逆相の最大電界が結合される。 In the rotating antenna 8 of the first embodiment, the microwave energy coupled in the coaxial mode by the coupling hole 6 and the inner conductor 7 is sandwiched between the rotating antenna 8 and the bottom surface of the high-frequency supply chamber 3, and the space is opened from the center of the rotating antenna 8 to the rotating antenna 8. It is transmitted as a spherical wave radially toward the outer periphery. In this embodiment, the difference in length (L 2 −L 1 ) between the two line segments is selected to be approximately ½ of the wavelength of the supplied microwave, so that the electric field strength is maximum at the slit A (8a). When coupled, the maximum electric field of the opposite phase is coupled at the slit B (8b) separated by ½ wavelength.

また、スリットA(8a)、スリットB(8b)は長軸が互いに直角に配置されるために、スリットA(8a)とスリットB(8b)から放射されるマイクロ波エネルギーの電界ベクトルは90°回転した状態で加熱室1内の被加熱物12に放射される。したがって、スリットA(8a)、スリットB(8b)での電界ベクトルが逆相であっても電界強度が弱まったり、打ち消されたりすることはなく、被加熱物12が効率よく加熱される。   Further, since the long axes of the slit A (8a) and the slit B (8b) are arranged at right angles to each other, the electric field vector of the microwave energy radiated from the slit A (8a) and the slit B (8b) is 90 °. Radiated to the object to be heated 12 in the heating chamber 1 in a rotated state. Therefore, even if the electric field vectors in the slit A (8a) and the slit B (8b) are in reverse phase, the electric field strength is not weakened or canceled out, and the object to be heated 12 is efficiently heated.

さらに、回転アンテナ8の形状をパラボラアンテナ状としたので、回転アンテナの放射角を非加熱物である水のブリュースタ角に近づけることができるという効果がある。すなわち回転アンテナ8の形状をパラボラアンテナ状としたことで、回転アンテナの放射角が水負荷のブリュースタ角70度〜80度前後(水の被誘電率で異なる)に近づき反射波が小さくなるので放射したマイクロ波エネルギーの大部分が非加熱物である水に吸収され加熱効率が向上する(水に入射するマイクロ波の入射角度がブリュースタ角に等しくなると反射波がなくなり水に放射したマイクロ波がすべて水に吸収されるようになる。アンテナの放射角度と水の入射角度は幾何学的には錯角の関係にあり、例えばアンテナの放射角が70度ならば水へのマイクロ波の入射角度も70度となる。)。   Furthermore, since the shape of the rotating antenna 8 is a parabolic antenna, the radiation angle of the rotating antenna can be brought close to the Brewster angle of water that is a non-heated object. That is, since the shape of the rotating antenna 8 is a parabolic antenna, the radiation angle of the rotating antenna approaches 70 to 80 degrees Brewster angle of water load (differs depending on the water permittivity), and the reflected wave becomes small. Most of the radiated microwave energy is absorbed by water, which is not heated, and heating efficiency is improved. (When the incident angle of the microwave incident on the water becomes equal to the Brewster angle, the reflected wave disappears and the microwave radiated to the water. The radiation angle of the antenna and the incident angle of water are geometrically in a complex relationship, for example, if the radiation angle of the antenna is 70 degrees, the incident angle of the microwave to water Is also 70 degrees).

次に、図3を用いて、本実施例の回転アンテナ8による加熱特性の改善効果を説明する。2線分の長さの差(L2−L1)と加熱特性の関係を調べるため、500mlの耐熱性ビーカに入れた125ml、285mlの水負荷を被加熱物12として被加熱物載置板2に載置し、(L2−L1)を変化させた場合に、被加熱物12に吸収される電力を電磁解析手法で解析し、この解析結果を図3に示す。 Next, the improvement effect of the heating characteristic by the rotating antenna 8 of the present embodiment will be described with reference to FIG. In order to investigate the relationship between the difference between the lengths of the two segments (L 2 -L 1 ) and the heating characteristics, a heated object mounting plate with 125 ml and 285 ml of water load placed in a 500 ml heat resistant beaker as the heated object 12 2, when (L 2 −L 1 ) is changed, the power absorbed by the article to be heated 12 is analyzed by an electromagnetic analysis method, and the analysis result is shown in FIG.

解析は、L1を15mmに固定し、L2を変化させて、(L2−L1)をλ/4(40mm)、3λ/8(45mm)、λ/2(60mm)、5λ/8(75mm)とすることで行った。ここで、λは供給されるマイクロ波の波長(≒120mm)である。図3からも明らかなように、水負荷125ml、285mlとも、(L2−L1)がλ/2で最大の吸収電力値となることがわかる。このことからも、図2に示した本実施例の回転アンテナ8の加熱特性が良いことが確認でき、この回転アンテナ8を用いた本実施例の高周波加熱装置では、加熱室1内に高周波エネルギーが効率よく導入され、被加熱物12が短時間で加熱することができる。 In the analysis, L 1 is fixed to 15 mm, L 2 is changed, and (L 2 −L 1 ) is changed to λ / 4 (40 mm), 3λ / 8 (45 mm), λ / 2 (60 mm), 5λ / 8 (75 mm). Here, λ is the wavelength of the supplied microwave (≈120 mm). As is apparent from FIG. 3, it can be seen that the maximum absorbed power value is obtained when (L 2 −L 1 ) is λ / 2 for both the water loads 125 ml and 285 ml. Also from this, it can be confirmed that the heating characteristics of the rotating antenna 8 of this embodiment shown in FIG. 2 are good. In the high-frequency heating apparatus of this embodiment using this rotating antenna 8, high-frequency energy is contained in the heating chamber 1. Is efficiently introduced, and the article to be heated 12 can be heated in a short time.

以上で説明したように、本実施例の高周波加熱装置によれば、2線分の差(L2−L1)を供給されるマイクロ波の波長のおよそ1/2としたので、結合穴6と内導体7で同軸モード結合されたマイクロ波エネルギーが、回転アンテナ8と高周波供給室3底面で挟まれ空間を回転アンテナ8の中心から外周囲に向かって放射状に球面波として伝送される。また、スリットA(8a)、スリットB(8b)での電界ベクトルが逆相であっても電界強度が弱まったり、打ち消されたりすることはない。しかも回転アンテナ8の形状をパラボラアンテナ状としたので、回転アンテナの放射角を非加熱物である水のブリュースタ角に近づけることができるので効率よく被加熱物12を加熱できる。さらに、回転アンテナ8は円板で円板の中心0に回転軸があるために、ぶれが緩和され安定した回転を維持することができ、加熱室天井面と接触してスパークの発生、衝突音、こすれ音が発生するなどの問題がない。 As described above, according to the high-frequency heating device of the present embodiment, the difference (L 2 −L 1 ) between the two segments is set to about ½ of the wavelength of the supplied microwave. The microwave energy coupled in the coaxial mode by the inner conductor 7 is sandwiched between the rotating antenna 8 and the bottom surface of the high-frequency supply chamber 3 and is transmitted as a spherical wave in a radial pattern from the center of the rotating antenna 8 toward the outer periphery. Further, even if the electric field vectors in the slit A (8a) and the slit B (8b) are in reverse phase, the electric field strength is not weakened or canceled. In addition, since the shape of the rotating antenna 8 is a parabolic antenna, the radiation angle of the rotating antenna can be brought close to the Brewster angle of water, which is a non-heated object, so that the object to be heated 12 can be efficiently heated. Further, since the rotating antenna 8 is a disc and has a rotation axis at the center 0 of the disc, the vibration is reduced and stable rotation can be maintained. There are no problems such as rubbing noise.

次に、図4を用いて実施例2の高周波加熱装置を説明する。なお、実施例1と同等の構成については説明を省略することとする。   Next, the high frequency heating apparatus of Example 2 will be described with reference to FIG. The description of the configuration equivalent to that of the first embodiment will be omitted.

実施例2の高周波加熱装置は、実施例1の回転アンテナ8に更にスリットを追加した実施例で、図4(a)は1個のスリットA(8a)と2個のスリットB(8b)を設け、図4(b)は2個のスリットA(8a)と2個のスリットB(8b)を設けたものである。   The high frequency heating apparatus of Example 2 is an example in which a slit is further added to the rotating antenna 8 of Example 1, and FIG. 4A shows one slit A (8a) and two slits B (8b). In FIG. 4B, two slits A (8a) and two slits B (8b) are provided.

図4(a)は、実施例1の回転アンテナ8に更にスリットB(8b)を設け、回転アンテナ8を挟んで二つのスリットB(8b)を対称に設けたものである。この構成では、図2の回転アンテナ8と同様の効果を得ることができるのに加え、2個のスリットB(8b)は回転アンテナ8の中心からの距離L2が等しいので2個のスリットB(8b)でのマイクロ波は同相で電界ベクトルも同じ向きとなるので、互いに打ち消すことがなく、それぞれの電界ベクトルが合成され強めあって放射されるという利点もある。 In FIG. 4A, the rotary antenna 8 of the first embodiment is further provided with a slit B (8b), and two slits B (8b) are provided symmetrically with the rotary antenna 8 interposed therebetween. In this configuration, in addition to being able to obtain the same effect as rotating antenna 8 of FIG. 2, two slits B (8b) because the equal distance L 2 from the center of the rotating antenna 8 two slits B The microwaves in (8b) have the same phase and electric field vectors in the same direction, so that they do not cancel each other, and there is an advantage that the respective electric field vectors are synthesized and strengthened and emitted.

図4(b)は、図4(a)の回転アンテナ8に更にスリットA(8a)を設け、回転アンテナ8を挟んで二つのスリットA(8a)を対称に設けたものである。この構成では、図4(a)の回転アンテナ8と同様の効果を得ることができるのに加え、回転アンテナ8の中心0に対称となる二組のスリットを設けたので、同相で電界ベクトルが同じ向きのものが2組となり、図4(a)の回転アンテナ8を用いた場合よりも更に大きな電界強度のマイクロ波エネルギーが得られるという利点があり、加熱スピード高速化が期待できる。   In FIG. 4B, a slit A (8a) is further provided in the rotating antenna 8 of FIG. 4A, and two slits A (8a) are provided symmetrically with the rotating antenna 8 in between. In this configuration, in addition to obtaining the same effect as the rotating antenna 8 of FIG. 4A, two symmetrical slits are provided at the center 0 of the rotating antenna 8, so that the electric field vector has the same phase. There are two sets of the same direction, and there is an advantage that microwave energy having a larger electric field strength can be obtained than when the rotating antenna 8 of FIG. 4A is used, and an increase in heating speed can be expected.

図5を用いて実施例3の高周波加熱装置を説明する。なお、実施例1と同等の構成については説明を省略することとする。   The high frequency heating apparatus of Example 3 will be described with reference to FIG. The description of the configuration equivalent to that of the first embodiment will be omitted.

実施例3の高周波加熱装置は、実施例2の図4(a)の回転アンテナ8の各スリットを弧状とするとともに、スリットBから中心0に向かう弧状のスリットC(8c)と、回転アンテナ8の中心0を挟むようにスリットAの反対側に設けられたスリットD(8d)を設けた実施例である。   In the high-frequency heating device according to the third embodiment, each slit of the rotating antenna 8 of FIG. 4A according to the second embodiment is formed in an arc shape, the arc-shaped slit C (8c) from the slit B toward the center 0, and the rotating antenna 8 This is an example in which a slit D (8d) provided on the opposite side of the slit A is provided so as to sandwich the center 0 thereof.

回転アンテナ8を実用化するには加熱効率のみならず、被加熱物12に加熱むらが発生しないようにすることが求められる。そのため、図5の回転アンテナ8では、加熱むらを改善するために新たにスリットC(8c)とスリットD(8d)を設けて、加熱効率改善に加えて均一加熱を図った回転アンテナ8としている。   In order to put the rotating antenna 8 into practical use, not only the heating efficiency but also the heating unevenness of the article to be heated 12 is required not to occur. Therefore, in the rotating antenna 8 of FIG. 5, a slit C (8c) and a slit D (8d) are newly provided in order to improve uneven heating, and the rotating antenna 8 is designed to achieve uniform heating in addition to improving heating efficiency. .

この実施例では、スリットA8aとスリットB8bは長方形のスリットでなく、回転アンテナ8の中心0方向に中心を持った弧状スリットで構成されている。この理由は、結合穴6と内導体7で同軸モード結合されたマイクロ波エネルギーは、回転アンテナ8と高周波供給室3底面で挟まれ空間を回転アンテナ8の中心から外周囲に向かって放射状に球面波として伝送されるので、スリットを弧状にすることによりスリット長さ方向各部で等しいマイクロ波エネルギーの結合が期待される。すなわち、図2や図4の実施例では長方形状のスリットであったので、回転アンテナ8中心部0からのスリット幅Wまでの距離はスリットの中心から端に移動するに伴って長くなり、スリットの中心で最大の電界強度が結合するが端部はそれよりも弱い電界強度のマイクロ波エネルギーが結合することになるが、図5の実施例ではスリットを弧状スリットにすることでスリットの何れの位置に置いても同じ電界強度のマイクロ波エネルギーを結合させることができる。   In this embodiment, the slits A8a and B8b are not rectangular slits but arc-shaped slits having a center in the direction of the center 0 of the rotating antenna 8. This is because the microwave energy coupled in the coaxial mode by the coupling hole 6 and the inner conductor 7 is sandwiched between the rotating antenna 8 and the bottom surface of the high-frequency supply chamber 3 so that the space is radially spherical from the center of the rotating antenna 8 toward the outer periphery. Since it is transmitted as a wave, equal microwave energy coupling is expected at each part in the slit length direction by making the slit arc. That is, in the embodiment of FIG. 2 and FIG. 4, the slit was a rectangular shape, so the distance from the central portion 0 of the rotating antenna 8 to the slit width W becomes longer as it moves from the center of the slit to the end. The maximum electric field strength is coupled at the center of the center, but microwave energy having a weaker electric field strength is coupled to the end portion. In the embodiment of FIG. Even when placed at a position, microwave energy having the same electric field strength can be coupled.

なお、スリットCを設けることで、スリットBの放射電力を調整できるという効果があり、スリットDを設けることで、加熱むらを抑制できるという効果がある。   By providing the slit C, there is an effect that the radiation power of the slit B can be adjusted, and by providing the slit D, there is an effect that uneven heating can be suppressed.

1 加熱室
2 被加熱物載置板
3 高周波供給室
4 マグネトロン
5 導波管
6 結合穴
7 内導体
8 回転アンテナ
8a スリットA
8b スリットB
8c スリットC
8d スリットD
9 誘電体軸
11 駆動部
DESCRIPTION OF SYMBOLS 1 Heating chamber 2 To-be-heated object mounting plate 3 High frequency supply chamber 4 Magnetron 5 Waveguide 6 Coupling hole 7 Inner conductor 8 Rotating antenna 8a Slit A
8b Slit B
8c Slit C
8d Slit D
9 Dielectric shaft 11 Drive unit

Claims (3)

被加熱物を収容する加熱室と、
該加熱室の底面に設けられた誘電体からなる被加熱物載置板と、
該被加熱物載置板の下方で前記加熱室の底面中央部に設けられた高周波供給室と、
マイクロ波エネルギーを発生するマグネトロンと、
該マグネトロンを取り付ける導波管と、
該導波管に導かれたマイクロ波エネルギーを前記高周波供給室に放射するために高周波供給室底面略中央部に設けられた結合穴と、
該結合穴を貫通して前記高周波供給室内へ略垂直に臨んで設けられた内導体と、
該内導体の一端の前記高周波供給室内に略水平に連結され、前記加熱室側を凸にしたパラボラアンテナ状かつ金属性の回転アンテナと、
前記内導体の前記導波管内で連結された誘電体軸と、
該誘電体軸を回転駆動する駆動部を備え、
前記回転アンテナには、第1のスリットと第2のスリットが設けられており、
前記第1のスリットの中心と回転アンテナ中心0を結ぶ線分L1、前記第2のスリット中心と回転アンテナ中心0を結ぶ線分L2としたとき、
線分L1と線分L2が略直行し、線分L1と線分L2の長さの差(L2−L1)が前記マグネトロンから供給されるマイクロ波の波長の約1/2であることを特徴とする高周波加熱装置。
A heating chamber for storing an object to be heated;
A heated object mounting plate made of a dielectric provided on the bottom surface of the heating chamber;
A high-frequency supply chamber provided in the center of the bottom surface of the heating chamber below the heated object placing plate;
A magnetron that generates microwave energy;
A waveguide for mounting the magnetron;
A coupling hole provided at a substantially central portion of the bottom surface of the high-frequency supply chamber for radiating the microwave energy guided to the waveguide to the high-frequency supply chamber;
An inner conductor provided through the coupling hole and facing substantially vertically into the high-frequency supply chamber;
A parabolic antenna-like and metallic rotating antenna that is connected substantially horizontally to the high-frequency supply chamber at one end of the inner conductor and has a convex side on the heating chamber;
Dielectric axes connected within the waveguide of the inner conductor;
A drive unit that rotationally drives the dielectric shaft;
The rotating antenna is provided with a first slit and a second slit,
When a line segment L 1 connecting the center of the first slit and the rotating antenna center 0 and a line segment L 2 connecting the second slit center and the rotating antenna center 0 are obtained,
The line segment L 1 and the line segment L 2 are substantially perpendicular, and the difference in length between the line segment L 1 and the line segment L 2 (L 2 −L 1 ) is about 1 / wavelength of the microwave supplied from the magnetron. 2. A high-frequency heating device, wherein
請求項1に記載の高周波加熱装置において、
前記第1のスリットおよび前記第2のスリットは弧状のスリットであり、
各スロットの弧の中心は、前記回転アンテナの中心方向にあることを特徴とする高周波加熱装置。
In the high frequency heating apparatus according to claim 1,
The first slit and the second slit are arc-shaped slits;
The center of the arc of each slot is in the center direction of the rotating antenna.
請求項2に記載の高周波加熱装置において、
更に、前記第2のスリットから前記回転アンテナの中心に向かう第3のスリットが設けられていることを特徴とする高周波加熱装置。
In the high frequency heating apparatus according to claim 2,
Further, a third slit is provided, wherein a third slit is provided from the second slit toward the center of the rotating antenna.
JP2012095207A 2012-04-19 2012-04-19 High frequency heating device Pending JP2013222672A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111417226A (en) * 2019-01-04 2020-07-14 青岛海尔股份有限公司 Heating device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111417226A (en) * 2019-01-04 2020-07-14 青岛海尔股份有限公司 Heating device

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