JPH01112635A - Magnetron device - Google Patents

Abstract

PURPOSE:To increase the heat radiating efficiency due to cooling air by furnishing the outside surface of an anode cylinder with heat radiating fins equipped with a number of protruding edges having twisted part in such a way as in layers. CONSTITUTION:Cooling air is sent in from one side of a frame yoke 7 of a magnetron 1 to be exhausted upon heat exchange with the inside. Heat radiating fins 8 are installed at the outside surface of an anode cylinder 2 in such a way as in layers. Each heat radiating fin 8 is made of Al alloy etc., and provided with a number of protruding edges 8b separated by slits in the edge area facing the opening 7a for influx of cooling air. Each protruding edge 8b has a 90 deg. twisted part 8c. Heat radiating fins in this arrangement put the cooling air in contact with a comparatively large heat exchange surface, and flowing while generating turbulent air stream suppresses the wind force loss to the minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a forced air-cooled magnetron device used in microwave ovens and the like.

BACKGROUND ART In general, a magnetron in a forced air-cooled magnetron device is constructed integrally with an excitation means and an air-cooling means, as seen in Japanese Patent Application Laid-Open No. 62-86639.

The excitation means includes at least an annular permanent magnet stacked over a first magnetic pole piece of the magnetron so that one magnetic pole is magnetically coupled to the magnetic pole piece, and the other magnetic pole of the permanent magnet is stacked on the first magnetic pole piece of the magnetron. a frame-shaped yoke magnetically coupled to the other magnetic pole piece, and the air cooling means mainly includes:
It consists of a large number of heat dissipating fins mounted in multiple stages on the outer peripheral surface of the anode cylinder and exposed to forced air cooling airflow.

The magnetron of the device configured in this way is cooled by a large number of heat dissipating fins and the forced air cooling airflow flowing between them, so that the temperature of the permanent magnet on the magnetic pole piece, which becomes particularly hot during operation, is reduced due to the temperature rise. Can prevent magnetic force decline. However, in order to achieve this, it is important to make the surface area of the radiation fins as large as possible to ensure good contact with the cooling airflow.

Therefore, as disclosed in Japanese Utility Model Publication No. 58-50608, etc., bending parts are provided in the radiation fins, and both sides of the radiation fins are brought into contact with both (1111) walls of the frame magnetic yoke. .

Problems to be Solved by the Invention However, simply bending a portion of the heat dissipation fin does not significantly improve the contact between the two, unless the plate surface of the heat dissipation fin intersects the direction of flow of the cooling airflow. On the other hand, depending on the way the intersections are made, a resistance effect may occur that prevents airflow from flowing between the radiating fins, and if this occurs, the cooling efficiency will be reduced.

Means for Solving the Problems The present invention provides a magnetron having first and second magnetic pole pieces facing each other at both open ends of an anode barrel, and a magnetron having a first magnetic pole piece and a second magnetic pole piece stacked on top of the first magnetic pole piece. an annular permanent magnet whose magnetic pole is magnetically coupled to the first magnetic pole piece; the other magnetic pole of this permanent magnet is magnetically coupled to the second magnetic pole piece; In a magnetron device comprising a frame-shaped yoke through which a forced air cooling airflow flows toward an opening, and a large number of radiation fins attached in multiple stages to the outer peripheral surface of the anode cylinder and exposed to the forced air cooling airflow. The radiation fin has a large number of projecting edges separated by slits on the surface side of the opening, and each of the projecting edges has a twisted portion.

Function: With this configuration, the large number of the protrusions lined up on the airflow introduction side of the heat dissipation fins have twisted portions, which not only improves the contact between the incoming airflow and the heat dissipation fins, but also
Since the airflow advances along the twisted portion and causes turbulence, it is possible to minimize wind power loss and efficiently suppress abnormal temperature rises in the magnetron and permanent magnet.

Embodiments Next, the present invention will be explained in detail together with embodiments shown in the drawings.◇ As shown in FIG. 1, the anode cylinder 2 of the magnetron 1 is
A first annular permanent magnet 5 made of ferrite is stacked on the outer end surface of the first magnetic pole piece 3 and has first and second magnetic pole pieces 3 and 4 attached to both open ends thereof. The magnetic pole N is magnetically coupled to the first magnetic pole piece 3. Further, a second annular permanent magnet 6 made of ferrite provided on the outer end surface of the second magnetic pole piece 4 magnetically couples one magnetic pole S to the second magnetic pole piece 4 . The other magnets and poles of the first and second annular permanent magnets 5 and 6 are magnetically coupled by a frame-shaped yoke 7. Furthermore, a large number of heat dissipating fins 8 are installed in multiple stages on the outer peripheral surface of the anode cylinder 2 of the magnetron 1, and the forced air cooling air flow passing between the plates is directed from one opening of the frame magnetic yoke 7. Enter and exit through the other opening.

In addition, 9 in the figure is a microwave emission terminal of the magnetron 1, 10 is a ceramic insulating ring, 11 is a gasket, 12
13 indicates a shield case, and 13 indicates a feedthrough capacitor.

The radiation fin 8 made of aluminum or its alloy has a cylindrical portion 8a into which the anode cylinder 2 is press-fitted, as shown in FIG.
It has a large number of projecting edges 8b separated by a large number of slits in the central region, and has a large number of projecting edges 8b separated by a large number of slits in the edge region facing the open lower a of the frame-shaped yoke 7. The edge 8b has a twisted portion 8c formed by twisting about 90 degrees.

In the magnetron device configured in this way, the twisted protrusion 8b of the radiation fin 8 comes into contact with the air cooling air flow sent from the fan (not shown) toward the frame-shaped yoke 7 over a relatively large area. , Moreover, the incoming airflow is transferred to the anode cylinder 2.
Since it acts to guide air to the side while creating turbulence, wind loss here can be minimized.

The flange 8b having the twisted portion 8c only needs to be formed on the side of the two openings of the frame-shaped yoke 7 into which the forced air cooling airflow is sent. However, when incorporating the magnetron device into a set such as a microwave oven, the capacitor 1
Because the front and back surfaces may be reversed depending on the position of the opening B8C, it is preferable to form the protrusion B8C on either side of the two openings.

Effects of the Invention Since the present invention is configured as described above, the air cooling efficiency for the magnetron can be improved without increasing the size of the radiation fins, the number of them used, or the supplied wind power, and the permanent magnet integrated into the magnetron can be improved. It is possible to prevent the coercive force from decreasing due to a rise in temperature, and it is also possible to downsize the heat dissipation fins and reduce the number of them used.

[Brief explanation of the drawing]

FIG. 1 is a side view of a magnetron device implementing the present invention;
Figure 2 is a partially cutaway perspective view of the radiation fins of the same device.
... Anode cylinder, 3.4... Magnetic pole piece, 5,
6・・・・・・・・・Permanent magnet, 7・・・・・・・・・
Frame-shaped yoke, 8...Radiation fin, 8a...
・・・・・・Cylindrical part, 8b・・・・・・Protrusion.

Claims (1)

[Claims] a magnetron having opposing first and second magnetic pole pieces at both open ends of an anode cylinder; stacked on the first magnetic pole piece and magnetically coupling one magnetic pole to the first magnetic pole piece; a ring-shaped permanent magnet, and a frame-shaped yoke that magnetically couples the other magnetic pole of the permanent magnet to the second magnetic pole piece, and allows forced air cooling to flow from one opening to the other opening. and a large number of heat radiation fins that are attached in multiple stages to the outer circumferential surface of the anode cylinder and are exposed to the forced air cooling airflow, and the heat radiation fins have a large number of ridges separated by slits on the surface side of the opening. 1. A magnetron device characterized in that the flange has a twisted portion.