JPS62290037A - Magnetron - Google Patents

Abstract

PURPOSE:To improve the mass-productivity and reduce the size of a magnet by providing the 1st cooling fin having a punched cylindrical projection which is fitted and fixed to the peripheral wall of an anode cylinder and a notch which allows an output antenna to pass through, and the 2nd cooling fin fitted and fixed to the peripheral wall of the punched cylindrical projection. CONSTITUTION:The 1st cooling fin 21 has a notch 22 to allow an output antenna 6 provided on the side surface of an anode cylinder 1 to pass through and a punched cylindrical projection 23 which is fitted and fixed to the peripheral wall of the anode cylinder 1, and is arranged opposedly interposing the output antenna 6 with both ends interposed by a yoke 16. The 2nd cooling fin 24 has a punched cylindrical projection 23a of a smaller height than the punched cylindrical projection 23 of the 1st cooling fin, and is fitted and fixed to the periphweral wall D of the punched cylindrical projection 23 of the 1st cooling fin. Radiation fins are mounted by fitting and fixing the punched cylindrical projection 23 of the 1st cooling fin to the peripheral wall of the anode cylinder 1, and then fitting and fixing the 2nd cooling fin 24 to the peripheral wall of the punched cylindrical projection 23.

Description

DETAILED DESCRIPTION OF THE INVENTION 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a magnetron used, for example, in a microwave oven, and particularly relates to an improvement in the cooling fin structure for cooling an anode cylinder.

Page 2/Conventional Technology As microwave ovens have become smaller and more compact in recent years, there has been a demand for smaller and lighter magnetrons, which are the main components. The factors that determine the size and weight of a magnetron are the magnet material and magnetic circuit configuration.
There is one disclosed in Publication No.-3943. This is intended to reduce the inner diameter of the magnet by arranging the output antenna perpendicular to the tube axis, improving the magnet utilization rate and making the magnet more compact.

FIG. 4 is a partial cross-sectional view of the conventional magnetron as described above, in which 1 is an anode cylinder, 2 is a cathode, 3 is a plurality of vanes, and 4
and 5 are magnetic poles, and 6 is an output antenna consisting of a microwave lead-out wire 7, a side tube 8, an antenna insulator 9, and a cap 10, and extends in a direction perpendicular to the axial direction of the anode cylindrical tube. 1
1.12 is a cylindrical magnet. The plurality of vanes 3 are arranged radially inside the anode cylinder 1, and the cathodes 2,
A working space is defined by the vane 3 and the magnetic pole 4.5. The DC voltage applied between the vane 3 and the cathode 23 and the magnetic field from the magnet 11.12 are applied orthogonally to this action space, and the thermoelectrons emitted from the cathode 2 reach the vane 3 without rotating. , a high frequency voltage is generated between the vanes 3. This high frequency voltage is applied to the microwave lead-out line 7.
The power is emitted from the output antenna 6 into the microwave oven and used as high-frequency power. In the figure, reference numeral 13 denotes a cathode stem, which has a conductor 14 and an insulator 15 for holding the cathode 2 and supplying power to the cathode 2. 16 is a yoke, and 17 is a cooling fin, which prevents the anode from being heated. 1
8 is a feedthrough capacitor, and 19 is a filter box, which prevents leakage of radio waves from the cathode 2 to the outside.

In the case of such a structure, that is, when the output antenna 6 is provided in a direction perpendicular to the axial direction of the anode cylindrical tube, the inner diameter of the magnet 12 on the opposite side to the cathode stem 13 can be made smaller, which improves the magnet utilization rate and increases the magnet utilization. Miniaturization can be achieved.

Problems to be Solved by the Invention A common method for mounting cooling fins on a magnetron is to provide a fitting hole in the cooling fin, press fit an anode cylinder into the fitting hole, and fix the anode cylinder. This is because it can be processed at room temperature compared to welding, brazing, etc., so there is no adverse effect of high temperature on the magnetron tube, and it is highly mass-producible.

In the conventional example described above, since the output antenna 6 is provided on the side surface of the anode cylinder 1, the cooling fins 17a located at the part where the output antenna 6 is led out are used for providing the output antenna 6 as shown in FIG. It is necessary to provide a notch 20. When the anode cylinder 1 becomes high in temperature, the cooling fins 17a deform in the direction shown by arrow A due to thermal expansion, resulting in poor contact with the anode cylinder 1 and deterioration of heat dissipation efficiency. Therefore, in the conventional example, the anode cylinder 1 and the cooling fins 17 must be joined by welding, brazing, etc., which may cause deformation of the anode cylinder 1 due to heat generated during joining, instability of oscillation characteristics due to oxidation, or machining. This has the problem of high cost.

In addition, a radiation fin 17 is provided at the part where the output antenna 6 is led out.
If no fins are provided, the heat dissipation area will be reduced and each heat dissipation fin will need to be made larger, which will increase the size of the entire magnetron.

Means for Solving the Problems In order to solve the above problems, the present invention provides a magnetron that extends perpendicularly to the anode cylinder axis and is provided with an output antenna on the side surface of the anode cylinder. a first cooling fin having a cylindrical cut-out portion that is fitted and fixed to the outer circumferential wall of the cylindrical cut-out portion and a notch portion through which the output antenna passes; It is equipped with two cooling fins.

Effect: With this configuration, the first cooling fin is provided with a notch for passing the output antenna through and is fitted and fixed to the anode cylindrical outer circumferential wall, and the second cooling fin is provided with a cutout in the cylindrical cutout of the first cooling fin.
In order to fit and fix the cooling fins, it is possible to install the cooling fins by fitting and fixing them to the anode cylinder, and also to provide heat dissipation fins in the part from which the output antenna is led out.

Example Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial sectional view of a magnetron according to the present invention, and FIG.
The figure shows an overall perspective view of a first cooling fin, which will be described later.
1 extends in a direction perpendicular to the tube axis of the anode cylinder 1 and is fitted and fixed to a notch 22 provided on the side surface of the anode cylinder 1 for passing the output antenna 6 and the outer peripheral wall of the anode cylinder 1. The cooling fin is a first cooling fin having a cylindrical cut-and-raised portion 23, and is provided facing each other with the output antenna 6 in between, and both ends are held by the yoke 16. 24
is a second cooling fin, which has a cylindrical cut-and-raised portion 2 that is shorter in height than the cylindrical cut-and-raised portion 23 of the first cooling fin 21.
3a, and is fitted and fixed to the outer peripheral wall of the cylindrical cut-and-raised portion 23 of the first cooling fin 21. Moreover, both ends are clamped by yoke 16. Here, the number of second cooling fins 24 is appropriately selected based on heat dissipation ability, pressure loss, etc.

7 b/' The rest is the same as the conventional example shown in FIG. 4, so the same symbols are given and the explanation is omitted.

In the above configuration, the heat dissipation fins are attached by fitting and fixing the cylindrical cut-out portion 23 of the first cooling fin 21 to the outer circumferential wall of the anode cylinder 1, and then optionally attaching the second cooling fin 24 to the cylindrical cut-out portion. This is done by fitting and fixing it to the outer peripheral wall of 23.

Therefore, since the cooling fins can be fitted and fixed, there is no need for welding, brazing, etc., and there is no adverse effect on the magnetron tube due to high temperatures. Also, mass productivity can be improved. Furthermore, since the first cooling fin 21 is provided with the notch 22 through which the output antenna 6 passes, the cooling fin can also be provided in the portion where the output antenna 6 is led out, and the radiation fin can be made smaller.

Further, since the cylindrical cut-and-raised portion 23 of the first cooling fin 21 has a large height in the tube axis direction, a large contact area with the anode cylinder 1 can be secured. Therefore, it has the effect of improving heat conduction and improving heat dissipation characteristics.

FIG. 3 shows another embodiment of the present invention, in which a second cooling fin 24 is fitted and fixed to the outer circumferential wall of the cylindrical cut-out portion 23 of the first cooling fin, and cooling fin 24
Another cooling fin 2 is attached to the outer peripheral wall surface of the cylindrical cut-and-raised portion 23a.
5 are fitted and fixed.

In this embodiment, even if the size of the output antenna 6 and the position of the output antenna from the side surface of the anode cylinder 1 change, the dimensions of the notch 22 of the first cooling fin 21 and the notch 22 of the second cooling fin 24 are changed. By providing this, there is an effect that fitting and fixing can be made possible.

Effects of the Invention As detailed above, according to the present invention, the following effects can be obtained.

(1) How to install a cooling fin even in a structure in which the extending antenna is provided in a direction perpendicular to the tube axis in order to fit and fix the second cooling fin to the cylindrical cut-and-raised part of the first cooling fin. Alternatively, a method of fitting and fixing can be used. Therefore, mass productivity is improved and the magnet can be made smaller.

(2) Since the first cooling fin is provided with a cut-off nine-vane top section that is commonly used for the output antenna, the cooling fin can also be provided in the portion where the output antenna is led out, and the cooling fin can be made smaller.

(3) Since the contact area between the cylindrical cut and raised portion of the first cooling fin and the anode cylinder can be increased, heat conduction is improved and heat dissipation characteristics are improved.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of a magnetron showing one embodiment of the present invention, FIG. 2 is an overall perspective view of the first fin of the magnetron, and FIG. 3 is a cross-sectional view of a main part showing another embodiment of the present invention. figure,
Figure 4 is a partial cross-sectional view of a conventional magnetron;
The figure is a sectional view of the same main part. 1... Anode cylinder, 2... Cathode, 3...
...Vane, 4.5...Magnetic pole, 6...
... Output antenna, 11.12 ... Magnet, 21
・・・・・・First cooling fin, 22・river・notch part,
23.23a... Cylindrical cut and raised portion, 24...
...Second cooling fin.

Claims (1)

[Claims] a plurality of vanes provided radially inside the anode cylinder;
a cathode provided in the axial direction of the anode cylinder; a pair of magnetic poles and magnets provided on both sides of the cathode in the axial direction; an output antenna provided on a side surface; a first cooling fin having a cylindrical cut-out portion that is fitted and fixed to the outer peripheral wall of the anode cylinder; and a cut-out portion that penetrates the output antenna; and the cylindrical cut-out. A magnetron comprising a second cooling fin having a cylindrical cut-and-raised portion that is fitted and fixed to the outer peripheral wall of the raised portion.