JP3331230B2 - Magnetron - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron,
In particular, the present invention relates to a magnetron having a structure in which radio wave leakage at a connection part of a filter case installed on the input side of a magnetron vacuum vessel is prevented to maintain its performance and improve reliability and to improve mass productivity.

[0002]

2. Description of the Related Art Since a magnetron efficiently generates high-frequency output, it is used in various fields such as radar devices, medical equipment, and cookers. However, there is a drawback that the leaked radio wave of the oscillating microwave may cause radio interference to communication devices and the like, and may cause harm to the human body.

In order to prevent this leaked radio wave, a countermeasure such as adding a filter to an input portion of the magnetron and shielding the input portion with a metal cover (filter case) is taken. FIG. 10 is a cross-sectional view for explaining the structure of a conventional magnetron, wherein 2 is a lower magnet, 3 is a lower yoke, 4 is a lower sealing component, 41 is a flange-shaped sealing material of the lower sealing component 4, 6 is a filter case, 8 Is an input side ceramic, 101 is a cathode (cathode filament), 102
Is an anode vane, 103 is an anode cylinder, 104 is an upper magnet, 105 is a magnetic pole piece, 107 is an antenna lead, 108 is an antenna, 109 is an exhaust pipe, 110 is an antenna cover, 111 is a cylindrical insulator, and 112 is an exhaust pipe support. , 121 is an upper end shield, 122 is a lower end shield, 123 and 124 are cathode leads, 126 is a cathode terminal, 127 is a spacer, 128 is a sleeve, 13
1 is a choke coil, 132 is a feedthrough capacitor, 134
Is a lid, 141 is an upper seal part, 143 is a metal gasket, 144 is an upper yoke, and 145 is a cooling fin.

In FIG. 1, a plurality of anode vanes 102 are formed radially around a cathode 101. The plurality of anode vanes 102 are fixed to the anode cylinder 103 by brazing or the like, or are integrally formed with the anode cylinder 103 by extrusion or the like. Above the anode cylinder 103, a cylindrical upper magnet 104 is provided.
At the lower part, a cylindrical lower magnet 2 is installed,
The magnetic flux from the upper magnet 104 and the lower magnet 2 passes through the pole piece 105 and the cathode 101 and the anode vane 10.
A necessary DC magnetic field is generated in the vertical direction (the tube axis direction) with respect to the working space formed between the two. The lower yoke 3 and the upper yoke 144 pass magnetic flux from a magnet.

In such a structure, electrons emitted from the cathode 101 form a high-frequency potential on each anode vane 102 while circulating under the influence of a DC magnetic field, and oscillate high-frequency (microwave). The oscillated microwave is output from the antenna 108 through the antenna lead 107. FIG. 11 is a plan view for explaining details of only the anode portion of the magnetron shown in FIG.
02, 102 'are provided in the direction of the center O from the inner wall of the anode cylinder 103, and are arranged radially when viewed from an axis passing through the center O.

The anode vanes 102, 102 'are provided with a first strap ring 1 made of two annular bodies having different diameters.
61 and the second strap ring 162 are connected every other. FIG. 12 is a perspective view for explaining the strap ring in FIG. 11. The first strap ring 161 is a small-diameter strap ring, and the second strap ring 162 is a large-diameter strap ring.

FIG. 13 is an explanatory view of a main part of the anode vane portion of the magnetron shown in FIG. 10. The first strap ring 161 having a small diameter comes into contact with the anode vane 102, and a second strap ring having a large diameter is provided. The ring 162 is not in contact, the second strap ring 162 having a large diameter is in contact with the adjacent anode vane 102, and the first strap ring 161 having a small diameter is disposed without being in contact with the anode vane 102. The rings 161 and the second strap rings 162 are alternately joined to every other anode vane 102.

One of the anode vanes 102 has a structure shown in FIG.
As shown in FIG. 0, an antenna lead 107 for deriving a high frequency is planted by brazing. Anode vane 1
The antenna lead 107 implanted in the cylinder 02 is inserted through the pole piece 105 enclosed in one opening side of the anode cylinder 103, and is hermetically sealed to the end of the sealing part 141 which is a metal sealing body. A cylindrical insulator 111 is provided, and a cup-shaped exhaust pipe support 112 brazed to the outer periphery of the exhaust pipe 109 is brazed to one end of the cylindrical insulator 111.

After exhausting the inside of the magnetron tube, the exhaust pipe 109 is sealed off together with the antenna lead 107.
The antenna cover 110 is press-fitted and fixed to the exhaust support 112 to protect the tip. Here, a concave portion 109a formed by sealing off the exhaust pipe 109 and the antenna lead 107 is a choke portion for preventing unnecessary radio wave radiation.

As the cathode 101 for generating electrons, tungsten containing a small amount of thorium oxide (ThO ₂ ) is generally used. In order to improve the electron emission characteristics, a carbonized layer (W ₂ C) is formed on the surface of the cathode. The cathode 101 has a high melting point brazing material such as ruthenium.
It is engaged and supported by a molybdenum eutectic alloy or the like.

The upper end shield 121 and the lower end shield 122 are connected to cathode leads 123 and 12 respectively.
4 supported. These end shields 1
Molybdenum (Mo) is generally used for the cathodes 21 and 122 and the cathode leads 123 and 124 from the viewpoint of heat resistance and workability. The two cathode leads 123 and 124 are
The cathode leads 123 and 124 are supported by the input-side ceramic 8 and are soldered to the input-side ceramic 8 together with the cathode terminal 126 so as to maintain a vacuum tight state.

When vibration or impact is applied to the magnetron, the cathode leads 123 and 124 vibrate, and the manner of the vibration differs between the cathode leads 123 and 124.
In some cases, a mechanical stress is generated in the cathode 101 to cause disconnection of the cathode 101. To prevent this, a spacer 127 is used. Due to the action of the spacer 127, even if the cathode leads 123 and 124 vibrate, the movement of the cathode leads 123 and 124 due to the vibration becomes substantially the same, so that the stress applied to the cathode 101 can be reduced. The sleeve 128 is for supporting the spacer 127 at a predetermined position.

The cathode terminal 126 is connected to a choke coil 131. The choke coil 131 is connected to a feedthrough capacitor 132 for mounting the filter case 6 of the input section, and the feedthrough capacitor 132 is connected to a power supply. Cathode terminal 126
The choke coil 131 and the choke coil 131 are generally connected by welding. Further, the choke coil 131 and the feedthrough capacitor 132 are generally connected by welding.

Here, the choke coil 131 and the feedthrough capacitor 132 form a low-pass filter when the power supply side is viewed from inside the magnetron. This is cathode 1
The microwave generated in the working space between the cathode 101 and the anode cylinder 103 causes the cathode 101 and the cathode leads 123, 1
This is to prevent radiation to the outside through 24.

FIG. 14 is a plan view of the filter case portion when the input portion of the magnetron shown in FIG. 10 is viewed from the lower surface. The choke coil 131 is connected to the cathode terminal 126.
The choke coil 131 is connected to a feedthrough capacitor 132 in which the input case filter case 6 is attached, and the feedthrough capacitor 132 is connected to a power supply (not shown). FIG. 15 is a fragmentary sectional view for explaining the structure of a feedthrough capacitor.
51 is an insulating cover, 152 is a dielectric, 153, 156
Is an electrode.

In FIG. 1, a dielectric 152 is an electrode 15
3,156 together with the capacitor. Electrode 156
Has a role of attaching the feedthrough capacitor 132 to the filter case 6. The electrode 153 is shown as being separated in the lower left part of the figure, but is integrally connected to the terminal 154 in other cross sections. Reference numeral 155 denotes a silicon tube which serves as a cushioning material (damper) that covers the terminal 154 and does not impair the adhesion between the resin 157 and the dielectric 152. Further, 151a has a function of dividing the stress generated in the resin 157. And terminal 154
Is connected to the choke coil 131.

As shown in FIG. 10, each of the cathode leads 123 and 124 is connected in series with one end of a choke coil 131, and the other end of the choke coil 131 is connected to a capacitor 1
It faces the ground via 32. The filter case 6 of the input section is sealed by the lid 134 to prevent high frequency (microwave) from being radiated to the outside.

The input side ceramic 8 has a flange-shaped seal portion 4.
Anode cylinder 10 via lower sealing part 4 with
3 while maintaining the vacuum tightness.
Is the anode cylinder 103 via the upper sealing part 141
Is engaged while maintaining vacuum tightness. Also, the upper yoke 1
44 is an upper sealing part 1 via a metal gasket 143.
41 and is electrically connected. This sealing part 141
Has the same potential as the anode cylinder 103. Therefore, the upper yoke 144 has the same potential as the anode cylinder 103.

FIG. 16 is a top view of the magnetron.
The upper yoke 144 and the lower yoke 3 (FIG. 10) are generally connected by caulking. FIG. 17 is a schematic cross-sectional view of a principal part of one structural example illustrating a leakage radio wave sealing mechanism between a filter case of a conventional magnetron and a vacuum container for a magnetron, wherein 1 is an anode cylinder, 2 is a lower magnet, Is the lower yoke, 4 is the lower seal part, 5
Is a metallic tubular member, 51 is a protrusion, 52 is an outer diameter edge, 6 is a filter case, 61 is an inner diameter edge, and 8 is a ceramic.

As shown in FIG. 1, between the lower seal part 4 and the filter case 6, a metallic tubular member 5 is inserted into the lower seal part 4, and the inner circumferential surface of the metallic tubular member 5 The projection 51 provided in this way is fitted so as to abut against the lower seal component 4 and assembled. Further, between the metallic tubular member 5 and the filter case 6, the outer peripheral edge 52 on the filter case 6 side of the metallic tubular member 5 and the inner peripheral edge 61 of the filter case 6 are fitted and fitted so as to be in contact with each other. Have been.

The prior art relating to this type of magnetron is disclosed in Japanese Utility Model Laid-Open No. 52-50046.
No. 58-24370, or JP-A 2-3-2
No. 12139 is known.

[0022]

In the joint structure of the lower seal part 4 and the filter case 6 according to the prior art described with reference to FIG. 17, when an external force such as an impact is applied at right angles to the tube axis direction of the magnetron, Between the metallic tubular member 5 and the filter case 6 or the projection 51 of the metallic tubular member 5
There may be a gap between the lower seal part 4 and
Leakage of oscillating radio waves (microwaves) may occur through this gap, causing radio interference to peripheral devices, and depending on the size of this gap, leakage of a fundamental wave (2450 MHz) having a large energy may occur, causing a human body to leak. There is a risk of causing harm.

Further, since the metallic tubular member 5, the lower sealing part 4 and the filter case 6 are tightly fitted, the metallic cylindrical member 5 is inside the anode cylinder 1 when an external force such as the above-mentioned impact force is applied. The cathode may have an adverse effect such as eccentricity. When the eccentricity of the cathode occurs, there is a problem that the operating characteristics of the magnetron are deteriorated and the oscillation efficiency is reduced.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to produce a gap at a joint portion between a lower seal component and a filter case even when an external force such as an impact force is applied perpendicularly to the tube axis direction of the magnetron. An object of the present invention is to provide a magnetron having a structure for preventing leakage of an oscillating radio wave without using the structure.

[0025]

In order to achieve the above object, the present invention provides an anode cylinder having a cathode and an anode vane, a lower seal component having a flange-shaped seal on the anode cylinder side, and a lower seal component. A magnetron vacuum vessel having at least a connected insulator, an upper magnet and a lower magnet arranged at the upper and lower ends of an anode cylinder, and a cathode lead fixed to the magnetron vacuum vessel via a yoke and supplying power to the cathode. In a magnetron comprising a filter case for accommodating a connected filter, the lower seal part and the outer periphery of the insulator are fitted and inserted, and an extension is provided on the filter case side extending through a central opening of the filter case. An insulating elastic tubular member having a, fitted and inserted around the outer periphery of the elastic tubular member, at least A metal tubular member that penetrates the lower magnet and has a narrowed portion at one end, and the metallic cylindrical member that is interposed between the step portion of the narrowed portion of the metallic tubular member and the filter case; A lower gasket for electrically connecting the filter case, and a metallic tubular member and the lower seal component interposed between a flange-like seal material of the lower seal component of the metallic tubular member. An upper gasket for electrical connection and a leaked radio wave seal structure comprising the upper gasket are provided.

Further, the present invention provides a vacuum vessel for a magnetron having at least an anode cylinder having a cathode and an anode vane, a lower seal component having a flanged seal portion on the anode cylinder side, and an insulator connected to the lower seal component. And an upper magnet and a lower magnet disposed at the upper and lower ends of the anode cylinder, and a filter case that houses a filter fixed to the magnetron vacuum vessel via a lower yoke and connected to a cathode lead that supplies power to the cathode. In the magnetron, the lower sealing part and the outer periphery of the insulator are fitted and inserted, and an insulating elastic tubular member extending through a central opening of the filter case and extending therethrough. A metallic tubular shape having a flange-shaped portion fitted and inserted into the outer periphery and inserted between the filter case and the lower yoke Material, a lower gasket interposed between the lower yoke and the opposing portion of the filter case to electrically connect the flange portion of the metallic tubular member and the filter case, and the metallic tubular member, An upper gasket interposed between the flange-shaped sealing material of the lower sealing component and the electrical connection between the metallic tubular member and the lower sealing component, and a leakage radio wave sealing structure comprising: Magnetron.

Further, the present invention provides a vacuum vessel for a magnetron having at least an anode cylinder having a cathode and an anode vane, a lower seal component having a flanged seal portion on the anode cylinder side, and an insulator connected to the lower seal component. And an upper magnet and a lower magnet disposed at the upper and lower ends of the anode cylinder, and a filter case which accommodates a filter fixed to the magnetron vacuum vessel via a yoke and connected to a cathode lead for supplying power to the cathode. In the magnetron, a metallic tubular member having a flange portion inserted and inserted between the lower seal component and the outer periphery of the ceramic and inserted between the filter case and the lower yoke, the lower yoke and the filter A flange portion of the metallic tubular member interposed between opposed portions of the case and the filter; And a lower gasket, which is electrically connected to the lower gasket, and is inserted between a lower gasket of the lower gasket of the metal gasket and the lower gasket. An upper gasket for electrical connection and a leaked radio wave seal structure comprising the upper gasket are provided.

[0028]

In the above construction of the present invention, the insulating elastic tubular member fitted and inserted into the outer periphery of the lower seal component and the insulator is used to reduce impact force or the like on the lower seal component or the insulator. It has a buffering action against external force and prevents sparks between the filament lead and the metallic tubular part.

The lower gasket is interposed between the metallic tubular member and the filter case to electrically connect the metallic tubular member and the filter case, and the upper gasket is An electric connection between the lower sealing component and the metal tubular member is secured to prevent radio wave leakage due to displacement of the filter case due to an external force such as an impact force.

The metal tubular member having the narrowed portion on the inner side has an effect of centering both when the yoke and the filter case are assembled. Furthermore, the one provided with the metallic tubular member having the flange portion, the lower gasket and the upper gasket has the same shock resistance and radio wave leakage preventing effect as described above while simplifying the structure.

[0031]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a main part of a magnetron according to a first embodiment of the present invention, wherein 2 is a lower magnet, 3 is a lower yoke, 4 is a sealing component, 41 is a flange-shaped sealing material connected to the sealing component, 5 is a conductive tubular member, 53 is a throttle portion (or a stepped portion) of the conductive tubular member 5.
Say), 6 filter case, the insulating elastic tubular member 7, 71 is a small diameter extension of the resilient cylindrical member 7, 8 ceramic as an insulator, 91 lower conductive gasket (hereinafter, simply Reference numeral 92 denotes an upper conductive gasket (hereinafter, simply referred to as an upper gasket). Here, the gasket is formed by knitting and compression-molding a thin metal wire.

In the figure, an insulating elastic tubular member 7 is inserted around the outer periphery of the input-side sealing component 4 that penetrates the lower magnet 2 of the magnetron, and the metallic tubular member 5 is inserted through the outer periphery thereof. It becomes. The insulating elastic tubular member 7
A small-diameter extension portion 71 is provided so as to contact the outer periphery of the ceramic 8 located on the filter case 6 side. The small-diameter extension portion 71 extends inside the filter case 6 and surrounds the ceramic 8 in order to maintain insulation between the metallic tubular member 5 and the filament lead.

The metallic tubular member 5 has a narrowed portion 53 at a portion from the yoke 3 to the filter case. The narrowed portion 53 is inserted into the central opening of the filter case 6 with a clearance. The metallic tubular member 5 and the filter case 6 are electrically connected by a gasket 91 interposed between the metallic cylindrical member 5 and the step at the start portion of the throttle portion 53. The restricting portion 53 extends to the inside of the filter case, but may be any position as long as at least a position for sealing the central opening of the filter case 6.

The sealing part 4 is formed by connecting a flange-shaped sealing material 41 bent at right angles to the tube axis direction from the outer periphery to the lower magnet 2. An upper gasket 92 is interposed between the portion and the end of the metallic tubular member 5. A gasket 92 inserted between the lower gasket 91 and the flange-shaped sealing material 41 and the end of the cylindrical member 5 is inserted between the stepped portion at the start portion of the throttle portion 53 and a thin metal wire or the like. It is compression molded and can provide electrical continuity between the members interposed.Also, due to its elastic deformation, no gap is created even when the above members move slightly, preventing radio wave leakage. It has the effect of doing.

According to the present embodiment configured as described above, the metallic tubular member 5, the sealing portion 4, and the filter case 6
Is elastically bonded between them, so that even if an external force such as an impact force in the direction perpendicular to the magnetron tube axis is applied, there is no gap between them, and the oscillating radio wave leaks. I will not do it. Moreover, the insulating elastic tubular member 7 maintains the withstand voltage of the metallic tubular member 5 and the filament lead portion, and also has a buffer effect even when an external force such as an impact force perpendicular to the tube axis is applied to the tube axis. The eccentricity of the cathode can be prevented.

Further, since the metallic tubular member 5 is fitted and inserted into the outer periphery of the insulating elastic tubular member 7, it is coaxial with the magnetron vacuum vessel, and the lower magnet 2 is attached to the magnetron vacuum vessel. , Yoke 3, filter case 6
Are sequentially assembled, the metal tubular member 5 can guide each of the components, so that there is an effect that the assembly is facilitated.

FIG. 2 is a sectional view of a main part of a magnetron according to a second embodiment of the present invention, in which a throttle portion is located outside. In this embodiment, the metallic tubular member 5
Except for the structure in which the step 53 is separated from the insulating elastic tubular member 7 in the direction away from the elastic elastic tubular member 7, that is, the structure is located on the outside opposite to FIG.
It is the same as FIG. Therefore, this embodiment has the same operation and effect as the above embodiment except that the step 53 of the metallic tubular member 5 does not have the axial alignment effect described in FIG.

FIG. 3 is a sectional view of a main part of a magnetron according to a third embodiment of the present invention, and the same reference numerals as those in FIG. 1 correspond to the same parts. In the figure, the insulating elastic tubular member 7 fitted to the outer periphery of the input-side seal component 4 penetrating the magnetron lower magnet 2 is a straight pipe cylindrical shape, and the ceramic 8 The metal tubular member 5 extending to the inside of the filter case 6 surrounding the outer periphery of the filter case 6 has a lower yoke 3 and a flange portion 54 interposed between the opposed portions of the filter case 6. A lower gasket 91 similar to that of the above-described embodiment is interposed between the lower yoke 3 and the filter case 6 so as to abut on the tip of the flange-like portion 54 so that the metallic tubular member 5 and the filter case 6 And are electrically connected. Further, the lower gasket 91 may be arranged so as to wrap around the tip of the flange portion 54 or between the flange portion 54 and the filter case 6.

An upper gasket 92 similar to that described above is interposed between the sealing member 41 and the end of the metallic tubular member 5 on the side of the sealing component 4 so that the metallic tubular member 5 and the sealing component 4 are inserted. The electrical connection between is guaranteed. In the above description, the filter case 6 side of the elastic tubular member 7 has been described as extending beyond the outer periphery of the ceramic 8. However, the elastic tubular member 7 has at least a length that seals the center opening of the filter case 6. I just need.

In the present embodiment constructed as described above, similarly to the above-described embodiment, the metallic cylindrical member 5, the sealing component 4 and the filter case 6 are elastically joined to each other. Even when an external force such as an impact force in a direction perpendicular to the tube axis of the magnetron is applied, no gap is formed between the respective magnets, so that the oscillating radio wave does not leak. The insulating elastic tubular member 7 maintains the withstand voltage of the filter case 6 and the filament lead, and has a buffering action against external force such as an impact force perpendicular to the tube axis. The eccentricity of the cathode is prevented by the buffering action.

FIG. 4 is a sectional view of a main part of a magnetron according to a fourth embodiment of the present invention. The same reference numerals as those in FIG. 1 correspond to the same parts. In the present embodiment, unlike the third embodiment, there is no elastic tubular member, and a metallic tubular member 5 is directly inserted around the outer periphery of the input-side sealing component 4 that penetrates the magnet 2 of the magnetron. The metallic tubular member 5 has a flange portion 54 inserted between the lower yoke 3 and the opposing portion of the filter case 6 as in the third embodiment.

A lower gasket 91 similar to that of the above-described embodiment is interposed outside the portion where the lower yoke 3 of the flange portion 54 and the filter case 6 are opposed to each other to electrically connect the metallic tubular member 5 and the filter case 6 to each other. Connected to An upper gasket 92 similar to that described above is interposed between the end of the metallic tubular member 5 on the side of the seal component 4 and the seal material 41 to allow the metallic tubular member 5 and the seal component 4 to pass through. Electrically connected.

In the present embodiment constructed as described above, the metallic tubular member 5, the sealing component 4 and the filter case 6 are elastically joined to each other, as in the above embodiments. Even when an external force such as an impact force in a direction perpendicular to the tube axis of the magnetron is applied, no gap is formed between the respective magnets, so that the oscillating radio wave does not leak. In addition, since each member incorporated between the main body of the magnetron and the filter case has a simple shape and a small number of parts,
Its assemblability is further improved than in the previous embodiment.

According to each of the embodiments described above, the problems of the prior art can be solved and a highly reliable magnetron can be obtained. FIG. 5 is a side view of the magnetron according to the present invention as seen from the yoke side, showing an external appearance common to the above-described embodiments. The antenna 108 includes an upper seal part 141 and an upper yoke 14 with a cylindrical insulator 111 interposed therebetween.
4 is connected to the antenna lead described in FIG. Below the lower yoke 3, the filter case 6 is joined and fixed by the structure described in each of the above embodiments. Reference numeral 132 denotes a feedthrough capacitor.

FIG. 6 is a front view illustrating the external appearance of the magnetron as viewed from the cooling fin side. The temperature of the anode of the magnetron becomes high due to the heat radiation from the cathode 101 described above with reference to FIG. When the temperature of the anode becomes high, adverse effects such as changing the magnetic properties of the magnet and adversely affecting peripheral devices of the magnetron occur. The cooling fin 145 is for dissipating this heat generation.

FIG. 7 is an explanatory view of the cooling fin shape.
(A) is a plan view, (b) is a side view as viewed from the direction of arrow A in (a), and (c) is a side view as viewed from the direction of arrow B in (a). 6, the cylindrical portion 145a is fitted with the anode cylinder 103 in FIG. In FIG. 6, five cooling fins shown in FIG. 7 are used. Generally, during operation of the magnetron, cooling air is sent to the cooling fins by a cooling fan installed in an applied device such as a microwave oven.

FIG. 8 is a circuit diagram for explaining an example of a magnetron driving circuit. In FIG. 8, reference numeral 231 denotes a magnetron. A DC power supply 201 that supplies DC power to the switching power supply 209 includes a commercial AC power supply 203 and a full-wave rectifier 205. A filter 207 composed of a reactor and a capacitor is connected to a DC output terminal of the full-wave rectifier 205.
Is not to smooth the rectified current, but to prevent high-frequency noise contained in the oscillation current from leaking through the AC power supply, thereby preventing the propagation of interfering waves.

The switching power supply 209 includes a transistor 211 and is turned on / off by a drive circuit 241 driven by an on signal of an on signal generation circuit 237 controlled by a synchronization pulse generated by a synchronization pulse generator 235. . The switching power supply 209 includes a damper diode 21 connected in anti-parallel to the transistor 211.
5 and a resonance capacitor 213 connected in parallel.

The switching power supply 209 comprises a primary winding 219 and secondary windings 221, 223 and 224, 225.
, The primary winding 219 is connected to the filter 207 via the switching power supply 209, and the capacitor 213 and the primary winding 219 form a series resonance circuit. The secondary winding 221 is connected to the magnetron 231 through a voltage doubler rectifier including a capacitor 227 and a high voltage diode 229. Current detector 2
Reference numeral 33 denotes a load current flowing through the magnetron, and an averaging circuit 249 adds the difference from the set value of the output setter 251 to the synchronization pulse from the synchronization pulse generator 235 via the amplifier 257 as an average value to generate an ON signal. 237 as a control signal.

The secondary winding 225 is provided for heating the filament of the magnetron 231, and the other secondary winding 223 is for producing a voltage for output feedback. After the shaping, the signal is subjected to a predetermined time delay by the delay circuit 245, and is provided as a control signal of the ON signal generation circuit 237. The secondary winding 224 is provided to an auxiliary power supply 247, rectified and used as a power supply for a control circuit and the like.

Here, a high voltage of usually several KV is applied to the filament and the anode. In the figure, reference numeral 232 denotes a waveguide, and 234 denotes a cooking chamber of a microwave oven. The microwave oscillated by the magnetron 231 is supplied to the cooking chamber 234 through the waveguide 232. FIG. 9 is a conceptual diagram for explaining a specific example in which the magnetron of the above embodiment according to the present invention is applied to a microwave oven. Reference numeral 301 denotes a microwave oven, in which a heated object 303 is set from a door 302. 304 is a magnetron, 305 is an antenna, 306 is a magnetron power supply, 307 is a cooling fan,
308 is a cooling wind, 309 is a waveguide, and 310 is a stirrer.

In the same figure, the microwave generated by the magnetron 304 is supplied from the antenna 305 through the waveguide 309 to the cooking chamber 301 in which the object 303 to be heated is set. The stirrer 310 rotates in the cooking chamber 301 to diffuse microwaves so that the object to be heated 303 is uniformly heated. The cooling fan 307 sends cooling air 308 to the magnetron 304 to
31 is for cooling.

According to the above-described embodiment of the present invention, a highly reliable magnetron which can solve the problems of the prior art can be obtained. Note that the present invention is not limited to the structure described in each of the above embodiments, and it goes without saying that various modifications can be made without departing from the technical idea of the present invention.

[0054]

As described above, according to the present invention,
By making the insulating tubular member located on the outer periphery of the sealing part of the magnetron vacuum vessel elastic, the eccentricity of the cathode of the magnetron can be prevented, and the characteristic deterioration can be avoided. In the case of FIG. 1, the metallic tubular member 2 can guide each part when the lower magnet, yoke, and filter case are sequentially assembled into the magnetron vacuum vessel, so that the assembly is facilitated. There is.

Further, even when an external force such as an impact force perpendicular to the tube axis direction is applied to the magnetron, the radio wave is sealed by the elastic gasket and the radio wave leakage can be prevented. That is, by appropriately selecting the entire length of the metallic tubular member, a gasket is sandwiched between the tubular member whose one end is drawn and the filter case, and the other end is composed of the metallic tubular member and the magnetron body. And the radio wave leakage is effectively prevented.

As described above, according to the present invention, it is possible to eliminate the drawbacks of the prior art and provide a magnetron having excellent functions.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a first embodiment of a magnetron according to the present invention.

FIG. 2 is a sectional view showing a main part of a second embodiment of the magnetron according to the present invention.

FIG. 3 is a cross-sectional view illustrating a main part of a magnetron according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing a main part of a magnetron according to a fourth embodiment of the present invention.

FIG. 5 is a side view of the magnetron according to the present invention, as seen from the yoke side, showing an external appearance common to the above embodiments.

FIG. 6 is a front view of the magnetron according to the present invention, as viewed from the side of the cooling fins, for explaining an external appearance common to the above embodiments.

FIG. 7 is an explanatory view of a cooling fin shape common to the above embodiments of the magnetron according to the present invention, wherein (a) is a plan view,
(B) is a side view seen from the arrow A direction of (a), and (c) is a side view seen from the arrow B direction of (a).

FIG. 8 is a circuit diagram illustrating an example of a driving circuit common to each of the above embodiments of the magnetron according to the present invention.

FIG. 9 is a conceptual diagram illustrating a specific example in which the magnetron of each of the above embodiments according to the present invention is applied to a microwave oven.

FIG. 10 is a cross-sectional view illustrating an example of the structure of a conventional magnetron.

FIG. 11 is a plan view illustrating details of only an anode portion of the magnetron.

FIG. 12 is a perspective view illustrating a magnetron strap ring.

FIG. 13 is an explanatory view of a main part of an anode vane portion of a magnetron.

FIG. 14 is a plan view of a filter case portion when the input section of the magnetron is viewed from below.

FIG. 15 is a fragmentary sectional view for explaining the structure of a feedthrough capacitor of a magnetron.

FIG. 16 is a top view of the magnetron.

FIG. 17 is a schematic cross-sectional view of an essential part for explaining one structural example of assembly between a filter case and a main body of a conventional magnetron.

[Explanation of symbols]

 2 Lower Magnet 3 Lower Yoke 4 Seal Part 41 Sealing Material 5 Conductive Cylindrical Member 53 Restricted Portion of Conductive Cylindrical Member 54 Flange Portion of Conductive Cylindrical Member 6 Filter Case 7 Insulating Elastic Cylindrical Member 71 Elasticity Small-diameter extension 8 of a cylindrical member 8 Ceramic 91 Lower gasket 92 Upper gasket.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-138748 (JP, A) JP-A-62-285345 (JP, A) Fully open 1974-77050 (JP, U) Really open 1975 112759 (JP, U) 50-80353 (JP, U) 50-177262 (JP, U) 50-176263 (JP, U) (58) Field surveyed (Int. ⁷ , DB name) H01J 23/15

Claims (3)

(57) [Claims] 1. A magnetron vacuum vessel including at least an anode cylinder having a cathode and an anode vane, a lower seal component having a flange-shaped sealing material on the anode cylinder side, and an insulator connected to the lower seal component. A magnet case comprising: an upper magnet and a lower magnet arranged at upper and lower ends of the magnet; and a filter case which houses a filter fixed to a magnetron vacuum container via a yoke and connected to a cathode lead for supplying power to a cathode. Fitting and inserting around the periphery of the component and the insulator,
An insulating elastic tubular member having an extension on the filter case side extending through the center opening of the filter case, and fittingly inserted through the outer periphery of the insulating elastic tubular member; A metal tubular member that penetrates the lower magnet and has a step at one end; interposed between the step of the metal tubular member and the filter case to electrically connect the metal tubular member and the filter case; Upper part electrically connected between the lower gasket and the lower seal part by being interposed between the lower gasket to be electrically connected and the flange-shaped seal material of the lower seal part of the metal cylindrical member A magnetron comprising a gasket and a leaky radio wave seal structure. 2. A magnetron vacuum vessel including at least an anode cylinder having a cathode and an anode vane, a lower seal component having a flange-shaped sealing material on the anode cylinder side, and an insulator connected to the lower seal component. A magnet case comprising: an upper magnet and a lower magnet disposed at the upper and lower ends of the magnet; and a filter case fixed to the magnetron vacuum vessel via a lower yoke and accommodating a filter connected to a cathode lead for supplying power to a cathode. Fitted and inserted around the outer periphery of the seal component and the insulator,
An insulating elastic tubular member extending through the center opening of the filter case, fitted and inserted around the outer periphery of the elastic tubular member, and inserted between the filter case and the lower yoke; A metallic tubular member having a flange-shaped portion, and a lower portion interposed between the lower yoke and the opposed portion of the filter case to electrically connect the flange-shaped portion of the metallic tubular member to the filter case. A gasket; and an upper gasket interposed between the metallic tubular member and the flange-shaped sealing material of the lower seal component to electrically connect the metallic tubular member and the lower seal component. A magnetron having a leaky radio wave seal structure. 3. A magnetron vacuum vessel having at least an anode cylinder having a cathode and an anode vane, a lower seal component having a flange-shaped sealing material on the anode cylinder side, and an insulator connected to the lower seal component. A magnet case comprising: an upper magnet and a lower magnet arranged at upper and lower ends of the magnet; and a filter case fixed to the magnetron vacuum vessel via a lower yoke and accommodating a filter connected to a cathode lead for supplying power to a cathode. Fitted and inserted around the outer periphery of the seal component and the insulator,
A metallic tubular member having a flange portion inserted between the filter case and the lower yoke; and a flange-like portion of the metallic tubular member interposed between the lower yoke and the opposing portion of the filter case. A lower gasket for electrically connecting a portion and the filter case; and a metallic gasket and the lower sealing component interposed between the metallic tubular member and the flange-like sealing material of the lower sealing component. And an upper gasket for electrically connecting the gasket and a leaky radio wave seal structure.