JPS62237637A - Magnetron - Google Patents

Abstract

PURPOSE: To restrict the unnecessary radiation to a cathode stem, by composing a conductive side-tube and an auxiliary conductive sidetube to form two kinds of space dimensions, and supporting the second dielectric member by one end of the auxiliary conductive side-tube and the bend of a feeding line, as well as connecting the other end of the auxiliary conductive side-tube to the main side-tube. CONSTITUTION:An auxiliary conductive side-tube is arranged concentrically to a conductive side-tube, and composed to form spaces S1 and S2 of different sizes between the both side-tubes. The lengths of the tube portions l1 and l2 to form the spaces S1 and S2 respectively are made in specific sizes. Moreover, one end of the tube portion of the auxiliary side-tube to form the larger space S2 is extended to the conductive side-tube side and connected to the tube electrically by soldering, by pressing a pole piece 20 and the conductive side tube, or the like. Therefore, one end of the larger space S2 is shortcircuited electrically. In such a way, by short-circuitting one end of the larger space, and by selecting the sizes of S2, l1, and l2 at adequate values, a desired frequency transmission can be restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to magnetrons, and more particularly to improvements in filament support structures.

BACKGROUND OF THE INVENTION FIG. 3 shows a sectional view of a main part of an example of a conventional filament support structure. A filament 1 that emits thermoelectrons is arranged concentrically with the tube axis of the magnetron, and end hats 2 and 3 are arranged at both ends to prevent the thermoelectrons from deviating in the axial direction. The upper end hat 2 is fixedly supported on the upper end of the center supply line 4, and the lower end hat 3 is placed concentrically with the center supply line and not in contact with the center supply line, and is fixedly supported on the upper end of the side supply line 5. The center supply line and side supply line are connected to a terminal 8 via a conductor side pipe 6 and a dielectric cathode stem 7.
Along with 9, silver is soldered to the cathode stem.

Further, both supply lines are fitted into through-holes of a spacer 1o of the dielectric member, and a choke member 11 having a function of preventing displacement of the spacer and preventing radio wave leakage is welded and fixed to the center supply line. The spacer is for maintaining the wiring of both leads.

Problems to be Solved by the Invention In the cathode stem having the above-described structure, the filament portion is inevitably coupled with the microwave energy generated by the magnetron. This combined microwave energy transmits through both supply lines and attempts to leak out of the cathode stem, but the conventional configuration has insufficient performance to prevent this leakage, so terminals 8 and 9 are left with no clearance. It was necessary to install the filter in a sturdy filter case.

For this reason, strict management is required in terms of construction and manufacturing, and there is a strong desire to provide a filament support structure that suppresses unnecessary radiation from the terminals 8 and 9 to below the legally regulated value.

Means for Solving the Problems In order to solve the above problems, the present invention provides a structure in which an auxiliary conductor side tube made of a non-magnetic material is arranged concentrically with the conductor side tube within the conductor side tube section, and the auxiliary conductor side tube and the conductor side tube are connected to each other. The gap created by the auxiliary conductor side tube is configured in two types in order, one end of the sub-conductor side tube that forms a large gap is extended and joined to the conductor side tube, and power is applied to the sub-conductor side tube part and filament that form a small gap. A filament support structure is provided in which a spacer made of a second dielectric material is supported by a bent portion of a supply line.

Effect By adopting the above configuration, the gap space formed between the sub-conductor side pipe and the conductor side pipe resonates at a specific frequency depending on the configuration dimensions, which acts as a choke seal and prevents microwaves along the supply line. It has the effect of suppressing energy propagation. Further, the spacer made of the second dielectric material has the function of stably maintaining the concentric configuration of the conductor side tube and the sub-conductor side tube, maintaining the gap space in a desired structure, and stably maintaining the choke seal performance.

Example The present invention will now be described with reference to the accompanying drawings.

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

12 is an anode cylinder, 13 is a vane arranged radially within the anode cylinder, 14 is a filament, 15° 16 is an end hat, 17 is a center supply line, 18 is a side supply line, 19
．． 20 is a pole piece, 21 is a conductor side tube, 22 is a cathode stem made of a first dielectric material, 23 is a sub conductor side tube made of a non-uniform material, and 24 is a spacer which is a second dielectric member.

One end of the conductor side tube is welded to one end of the anode cylinder so as to press and fix the pole piece 2o, and the other end is silver soldered to the cathode stem. Also, both supply lines are connected to terminals 25 and 26.
It is also brazed to the cathode stem. The auxiliary conductor side pipe is arranged concentrically with the conductor side pipe, and the auxiliary conductor side pipe is configured to form two different gaps 81.32 between the side pipes. Also, each clearance SL
The sub-conductor side pipe length #1.12 forming S2 is configured to have a predetermined dimension. One end of the auxiliary conductor side pipe that forms an even larger gap s2 is extended to the conductor side pipe and electrically shorted to the conductor side pipe by brazing the conductor side pipe or suppressing the pole piece 2o and the conductor side pipe. ing. Therefore, one end of the large gap s2 is electrically shorted.

One end that forms a large gap is electrically short-circuited and the size S1.92. l! 1. 1) By selecting an appropriate value for 2, desired frequency propagation can be suppressed.

Now, set the desired frequency to 4, which is the second harmonic of the magnetron.
Assuming 900 Mllz, examples of each dimension of the above configuration are s1 = 1mm, S2 = 4mm, l! 1=(12
=4.5 gates should be selected. In this case 4910±25
>1IIx band was able to achieve a transmission loss of 20 dB or more.

By configuring the sub-conductor side tube with a non-magnetic material, a decrease in the elongation of the magnetic field in the working space 28 caused by the branching of the magnetic path of the magnet 27 is prevented.

Further, the spacer is fixedly supported by the bent portion 29 of the center supply line and the sub-conductor side pipe. In addition to maintaining the wiring positions of both supply lines, this spacer has the effect of arranging the sub-conductor side and meter concentrically with the conductor side pipe.

FIG. 2 is a sectional view of a main part of a magnetron showing another embodiment of the present invention. In the drawings, the same or equivalent parts as in FIG. 1 are indicated by the same numbers.

The difference from FIG. 1 is that in the two types of gap structures formed by the conductor side pipe 3o and the sub-conductor side pipe 31, one end 32 forming a small gap is electrically short-circuited.

If such a configuration is used, propagation of two different frequencies can be suppressed. As an example, each dimension in the figure is 33
=4.71m, 54=0.5ms, e3=14=12.
If it is set to 31++3, the propagation of the second and third harmonics of the magnetron can be suppressed.

In the two embodiments described above, the frequency of low-power suppression is not limited to harmonics of the magnetron firing frequency, but may also be used for subharmonics or parasitic wave numbers.

Effect of the invention As described above, according to the present invention, the following effects are achieved.

(1) Unnecessary radiation to the cathode stem can be suppressed.

(2) Since the sub-conductor side tube is made of a non-magnetic material, there is no magnetic path branching due to the addition of the sub-conductor side tube, so the same magnetic circuit structure as the conventional one may be used.

(3) Since it is co-assembled with the spacer, which is the second dielectric material, the sub-conductor side pipe can be used as a member for supporting and fixing the spacer, eliminating the need for extra members, and the spacer connects the sub-conductor side pipe and the conductor. The concentric arrangement of side pipes can be stably configured and the filter effect can be easily maintained.

4) Propagation of two desired frequencies can be suppressed by simply changing the gap arrangement structure.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main part of a magnetron showing one embodiment of the present invention, FIG. 2 is a sectional view of the main part of a magnetron showing another embodiment of the invention, and FIG. 3 is a main part of a magnetron showing a conventional example. FIG. 14...Filament, 17.18...Supply line, 21.30...Conductor side tube, 22...
... Cathode stem, 23.31 ... Subconductor side pipe, 24 ... River second dielectric member, 29 ... Bend part of supply line, (sl. S2), ( S3.S4) ...Two types of clearance dimensions. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 4
---Filamesito

Claims (1)

[Claims] A cathode stem made of a first dielectric material that supports a supply line that supplies power to the filament, a conductor side tube that supports the cathode stem, and a nonmagnetic material disposed concentrically within the conductor side tube. comprising a sub-conductor side pipe and a second dielectric member connected to the sub-conductor side pipe and through which the supply line passes, the conductor side pipe and the sub-conductor side pipe having two types of predetermined clearance dimensions. The magnetron is configured such that one end of the sub-conductor side tube is joined to the conductor side tube, and the second dielectric member is supported by the other end of the sub-conductor side tube and the bent portion of the supply line.