JPH02216733A - magnetron - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a metallized surface of a ceramic stem having a metallized surface only on the vacuum side or a metal plate bonded to the metallized surface, and a cathode support rod made of molybdenum. In a magnetron cathode support structure in which a magnetron cathode support structure is electrically connected to a cathode external connection line made of iron-based material, the withstand voltage characteristics between this relay connection (cathode potential) part and the anode potential part surrounding the outside thereof are improved. related to things.

[Prior Art] Magnetrons for microwave ovens are widely used for home use, so there is a strong demand for low prices, and the length of the expensive molybdenum cathode support rod that supports the hot cathode must be reduced as much as possible. There is a need. Therefore, 1 For example, JP-A-62-
Publication No. 55848 discloses that a part of the vacuum side surface of a ceramic stem inserted through an lla electrode support rod is metallized, and a cathode support rod made of molybdenum is connected to the metallized surface or a metal plate bonded to the metallized surface. It has been disclosed that the length of the cathode support rod made of molybdenum is shortened by electrically relaying the cathode external connection line made of an iron-based material.

[Problems to be Solved by the Invention] However, with the above technology, it is not possible to electrically connect the molybdenum H cathode support rod and the iron-based cathode external connection wire using the metallized surface on the vacuum side of the ceramic stem or the metal plate bonded thereto. In this case, the withstand voltage between this connection part at the cathode potential and the metal cylindrical body surrounding the outside and at the same potential as the anode cylinder or the annular metallized surface of the stem is insufficient, and sparks may occur. , leakage current often occurs.

The present invention solves the problems of the conventional technology as described above, and even when the cathode support rod and the cathode external connection wire are relay-connected on the vacuum-side metallized surface of the ceramic stem, the cathode potential can be connected. It is an object of the present invention to provide a magnetron cathode support structure in which sufficient withstand voltage characteristics can be obtained between the anode potential section and the anode potential section surrounding the outer side of the magnetron cathode support structure.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a tube shaft is attached to an end of a metal cylindrical body that is hermetically sealed to one end of an anode cylinder and forms a part of a vacuum envelope. The central part of the inside of the same end face is airtightly joined by the metallized outer annular groove of the end face perpendicular to A pair of semicircular metallized parts facing each other across the exposed insulating part are each provided with a hole of a predetermined depth through which one side of a molybdenum cathode support rod that supports the cathode via end hats at both ends is inserted, and a cathode external liquid f.
I! A through hole is provided through which one side of the wire is inserted and airtightly connected, and the cathode is supported, and the cathode support rod and the cathode external connection wire are electrically relay-connected using the metallized surface or a metal plate that connects the metallized surface and the metallized surface. In a magnetron cathode support structure equipped with a ceramic stem having a function of We decided to cover it with a metal relay plate that has a skirt part that covers a part of it and has a smooth outer surface (no sharp protrusions with a radius of curvature close to infinitesimal).

[Effects] By doing the above, the effects of the edge of the metallized surface and the cut surface of the flat metal plate bonded to the metallized surface, where electric fields tend to concentrate and cause discharge, are suppressed, and the withstand voltage characteristics are improved. Improved.

Even if the skirt portion is added as described above, the increase in material is small, and processing to smooth the outer surface can be economically performed by a method suitable for mass production, such as tumble processing.

[Example code] FIG. 1(a) is a sectional view of a main part of an embodiment of the present invention.

The filament cathode 1 is supported by cathode support rods 4.5 made of molybdenum via end hats 2.3 at the upper and lower ends. The cathode support rods 4.5 each have a pair of semicircular metallized parts 6b facing each other across an insulating part in which the central ceramic skin is exposed inside the vacuum side end face perpendicular to the tube axis of the ceramic stem 6. , 6c with a predetermined depth hole 4a.

5a, and is bonded and fixed with silver solder to a metal relay plate 7 that covers a part of the wall surface in the tube axis direction of the insulating groove 9 in which these metallized surfaces and the surrounding ceramic skin are exposed. There is. The relay plate 7 has a semicircular plane portion and is fixed by brazing to the metallized portion of the end face of the stem. On the other hand, 1
The pair of cathode external connection lines 8 each include a semicircular metallized portion 6b,
It is inserted into through holes 8a and 8b provided in 6c, and the metallized surface and the metal plate are joined by brazing, and at the same time, the ends of these through holes on the vacuum side are hermetically sealed. The large diameter portion of the upper end of the metal cylindrical body 10 is hermetically sealed to an anode cylinder of a magnetron (not shown), and the lower end is hermetically sealed to the outer annular metallized portion 6a of the vacuum side end surface of the stem 6. In addition, FIG. 1(b) is a top view of the stem 6, and FIG. 1(Q) is a top view of the relay plate 7.
shows a top view and a side view.

As described above, the molybdenum cathode support rod 4°5 is
They are relay-connected to the cathode external connection line 8 through the semicircular metallized portions 6b and 6c and the metal relay plate 7 covering them, respectively. Conventionally, a molybdenum cathode support rod penetrated a ceramic stem.

It was connected to an external connection line at the outside air side end of the through hole. Therefore, in this embodiment, the amount of molybdenum wire used can be reduced considerably.

A semicircular metallized portion 6b on the vacuum side end surface of the stem 6 is a relay portion between the cathode support rod and the external connection wire.

6c (and the relay plate 7 covering them) are approximately at cathode potential,
The outer annular metallized portion 6a (and the metal cylindrical body 10) is approximately at an anode potential (however, it is grounded).1 There is a potential difference between the cathode and the anode, for example, approximately 8 kV when the power is turned on.
A high voltage will be applied. Although there has been an annular groove 9 for insulation in the past, since the relay plate was a flat plate, there were many sharp protrusions on the outer peripheral end face and exposed metallized surface, and the electric field was concentrated on these, which caused the discharge to start. In the present invention, since the relay part of the cathode power supply path is covered with a relay plate with a smooth skirt and one surface, concentration of electric field does not occur.

It became difficult to discharge and the withstand voltage characteristics improved.

[Effects of the Invention] As explained above, according to the present invention, the amount of molybdenum wire used can be reduced, and the withstand voltage characteristics are good.

[Brief explanation of the drawing]

FIG. 1(a) is a sectional view of essential parts of an embodiment of the present invention, FIG.
b) is a top view of a ceramic stem, and FIG. 1(c) is a top view and side view of a relay plate according to the present invention. 1... Filament cathode, 2, 3... End hat, 4, 5... Cathode support rod, 4a, 5a...
Hole of predetermined depth, 6... Stem, 6a, 6b, 6
c...Metallized portion, 7...Relay plate according to the present invention, 8...Cathode external connection wire, 8a, 8b...Through hole, Fig. 91 r===koR Ying J! surplus kidney

Claims (1)

[Claims] 1. At the end of a metal cylindrical body that is hermetically sealed to one end of the anode cylinder and forms part of the vacuum envelope, an end face perpendicular to the tube axis is attached.
Airtightly joined by a metallized outer annular part, and insulated by an annular groove concave in the tube axis direction with respect to this joint, the surface of which is not metalized, inside the same end face, across the central exposed insulating part. A hole of a predetermined depth through which one of the cathode support rods made of molybdenum that supports both ends of the cathode is inserted, and one of the cathode external connection wires is inserted into each of the pair of opposing substantially semicircular metallized parts to form an airtight connection. A stem made of ceramics is provided with a through hole and has a function of supporting the cathode and electrically connecting the cathode support rod and the cathode external connection wire with the metallized surface or the metal plate bonded to the metallized surface and the metallized surface. In the magnetron cathode support structure, each of the semicircular metallized parts has a smooth outer surface, a semicircular flat part is joined to the metallized surface, and a part of the side wall surface in the tube axis direction of the annular groove is formed on the periphery of the flat part. A magnetron cathode support structure, characterized in that it is covered with a metal relay plate having a skirt portion that covers the magnetron cathode support structure.