KR940002926Y1 - Magnetron - Google Patents

Abstract

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Description

magnetron

1 is a longitudinal cross-sectional view showing the structure of a conventional magnetron.

Figure 2 is a main longitudinal cross-sectional view showing an embodiment of the present invention.

3 is an enlarged cross-sectional view of the stem insulator of FIG.

* Explanation of symbols for main parts of the drawings

11: filament cathode 13,45,46: terminal piece

15,16,41,42 Cathode lead 17,43 Stem insulator

20,22: soldering part 21: metal container

23: metal bonding plate 31: anode body

32: cathode filament 33: anode vane

34,35: magnetic pole piece 41,42: cathode lead

43: circular groove 44: metal plate

50: output terminal 56: exhaust pipe

57: insulated tube 58: metal tube

59: conductor for deriving microwaves

The present invention relates to a magnetron for an electronic engine, and more particularly, to a magnetron for a microwave oven having an improved stem insulator disposed on the cathode input side.

The conventional magnetron for microwave oven is known to have a structure as shown in FIG. That is, as shown in FIG. 1, the stem insulator 17 and the respective cathodes 15 and 16 are disposed on the cathode side of the stem insulator 17, that is, the metal bonding plate 23 at the side to be a vacuum region. It is a structure sealed by airtight using (23).

Insulation distances between the step insulator 17 and the metal container 21 from the solder parts 20 and 20 between the step insulator 17 and the cathode 15 and 16 can be ensured. The step is formed so that.

As is well known, magnetrons for microwave ovens generally have a metal vessel 21, which is integrally coupled with the anode, to which the earth potential is grounded. On the contrary, the cathode and the lead 15, 16 have a negative voltage, for example, 4 KV. To operate. By the way, in the conventional structure like FIG. 1, it is easy to produce a discharge by current leakage between the both solder parts 20 and 22 of the inner surface side of the special stem insulator 17. As shown in FIG. That is, since the airtight soldering part of the metal bonding plate 23 to the stem insulator 17 and the airtight soldering part 22 of the metal container 21 go through a peripheral edge, discharge generate | occur | produces between both. Particularly, in a microwave oven using a leakage transformer, when the power switch is inserted without preheating the filament cathode 11, an ideally high no-load voltage is applied to the magnetron in the initial stage when electrons are not emitted from the filament cathode 11, and the soldered part It is easy to generate a discharge between (20) and (22). In addition, some of the electrons emitted from the filament cathode 11 pass through the gap between the end hat 12 and the pole piece (not shown) and reach the stem insulator 17 as floating electrons.

The floating electrons collide with the inner surface of the stem insulator 17 to discharge secondary electrons from the ceramic to charge the ceramic surface. As a result, discharge is likely to occur between the surface of the stem insulator which is charged and becomes the high potential and mainly with the cathode leads 15, 16 or the metal bonding plates 23, 23.

In addition, in the magnetron having the structure as shown in FIG. 1, a microwave oscillation operation is performed using a fundamental wave of 2450 MHz. The difference voltage between the negative voltage and the positive voltage is usually 4 KV or more, so that the straight line distance between the negative electrode and the positive electrode, That is, in order to ensure the insulation distance between the terminal piece 13 and the metal container 21 more than 15.5 mm, ie, the creepage distance (distance along a surface) 17.5 mm or more through the stem insulator 17, the stem insulator 17 ) Is a cylindrical phenomenon, the length of the stem insulator 17 (L1) must be increased or the diameter (D) must be increased, so the stem insulator becomes larger, and the manufacturing cost increases with the increase in size. there was.

The present invention has been made in view of the above-mentioned shortcomings, and an object of the present invention is to form a circular groove in a stem insulator and to secure an insulation distance between a terminal piece and a metal container while miniaturizing and reducing the manufacturing cost. To provide a magnetron for the stove.

In order to achieve the above object, a magnetron according to the present invention is provided with a cathode body having a plurality of anode vanes on the inner circumferential surface of the cathode and a plurality of anode vanes protruding toward the cathode to form a resonant cavity, and are disposed opposite to each other at open end portions of the cathode cylinder. A high frequency oscillation apparatus in which a funnel-shaped first and second magnetic pole pieces for magnetic field convergence and a stem insulator for hermetically passing a pair of cathode leads through a metal tube at an input end of the anode cylinder are sealed. And a circular groove is formed between the terminal piece and the outer diameter of the stem insulator so as to secure an insulating distance between each one end of each terminal piece attached to the stem insulator and the metal tube.

In this way, the insulation distance from the one end of each terminal piece attached to the stem insulator can be secured through the creepage distance of the stem insulator, so that it can be prevented from being discharged from the surface of the stem insulator, so that the operation characteristics of the magnetron are stable. Will be.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 3 is an enlarged sectional view of the second stem insulator.

As shown in FIG. 2 and FIG. 3, in the cylindrical anode cylinder 31, the cathode filaments 32 between the end hats 37 and 38 supported by the respective cathodes 41 and 42, respectively. A plurality of anode vanes 33 are disposed on the inner circumferential surface so as to protrude toward the side to form a resonant cavity, and the first and second magnetic pole pieces 34 having a funnel shape for magnetic field convergence at both opening ends of the anode cylinder 31. 35 are disposed to face each other. And since the flange part 58a of the round metal pipe 58 sealed by the metal exhaust pipe 56 via the insulating pipe 57 which consists of ceramics covers the 1st pole piece 34, The other end of the microwave-conducting conductor 59 is connected to the inside of the exhaust pipe 56 as an antenna that is sealed at the open end of the anode cylinder 31 and extends from the anode vane 33. In addition, a metal cap-shaped microwave output terminal 50 is fixed to the outside of the exhaust pipe 56.

On the other hand, as shown in detail in FIG. 3, the ceramic cup-shaped stem insulator 3 which hermetically penetrates the pair of cathode rides 41 and 42 has another round metal tube at its open end. It is sealed by the solder | pewter 44, and is sealed by the input side opening edge part of the anode cylinder 31 so that the 2nd pole piece 35 of the flange part 44a of this metal pipe 44 may be covered.

Further, the stem insulator 3 and the pair of cathode leads 41 and 42 are hermetically sealed by a pair of terminal pieces 45 and 46 disposed outside the bottom of the stem insulator 3. , Between one end of each pair of terminal pieces 45 and 46 disposed on the stem insulator 43 and the outer diameter of the stem insulator 43, ie, outside the attachment point of the terminal pieces 45 and 46; A circular groove 43a having a width W of at least 1 mm and a depth of h is formed in the gap between the terminal piece 45 (or terminal piece 46) and the metal pipe 44 via the stem insulator 43. The insulation distance is 15.5 mm or more, specifically, the distance along the surface of the stem insulator 43 is 17.5 mm or more.

In this configuration, since the creepage distance of the stem insulator 43 is formed along the circular groove 43a, the depth h of the circular groove 43a is lower than that of the conventional stem insulator 17 in which the circular groove is not formed. At least twice the length can be secured.

As described above, according to the present invention, a groove having a width (w) of at least 1 mm and a depth of h is formed on the outside from each one end of the pair of terminal pieces disposed on the stem insulator, and thus applied to the conventional magnetron. Compared with the stem insulator, the height dimension can be reduced by at least 2h, or the outer diameter of the stem insulator can be reduced by the length corresponding to 2h. Therefore, the size of the stem insulator and the magnetron can be made smaller, and the manufacturing cost can be reduced. There is an excellent effect that can be down.

Claims (3)

The anode cylinder 31 having a plurality of anode vanes 33 on the inner circumferential surface of the cathode 32 and the cathode vanes 33 protruding toward the cathode 32 to form a resonant cavity, and opposite opening ends of the anode cylinder 31 on both sides thereof. A pair of cathode leads 41 having a funnel-shaped first and second magnetic pole pieces 34 and 35 for magnetic field converging and a metal tube 44 at the input end of the anode cylinder 31. In the high frequency oscillation apparatus in which the stem insulator 43 for hermetically penetrating the 42 is hermetically sealed, one end of each terminal piece 45 and 46 attached to the stem insulator 43 and a metal tube ( A magnetron, characterized in that a circular groove (43a) is formed between the respective terminal pieces (45) (46) and the outer diameter of the stem insulator (43) to secure an insulation distance from the 44. The magnetron according to claim 1, wherein the circular groove (43a) has a width (W) of at least 1 mm and a depth of h. A magnetron according to claim 1, wherein said stem insulator (43) is made of ceramic.