JPH03250537A - magnetron - Google Patents

Abstract

PURPOSE:To prevent gasket from slipping off and enhance the electric contacting condition by furnishing a plurality of notches at the periphery of the wall surface at the end of a metal cylinder which supports a high frequency output part, bending the thin ridge obtained to the outside, and holding the gasket filling the gap relative to a yoke. CONSTITUTION:With an insulating member interposed, a high frequency output part 11 is supported through a penetrative hole provided in a permanent magnet 12 forming a magnetic field in the acting space of magnetron and a yoke 13 forming a magnetic circuit as surrounding the body of magnetron situated outside the mentioned permanent magnet 12, and a plurality of notches are furnished at the wall surface at the end of a metal cylinder 14 which is itself working as a grounding electrode, and thus a thin ridge 18 is formed. A resilient ring-shaped gasket 16 equipped with high electroconductivity, which fills the gap between the penetrative hole and the cylinder 14 and prevents leakage of electric waves, is held by bending the thin ridge 18 outside. This hinders the gasket 16 to displace, and electric contact with the cylinder and yoke 13 can be maintained in good performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetron that reliably prevents detachment of a highly conductive gasket that fills the space between a high frequency output section and a yoke to prevent radio wave leakage.

[Prior art] At the point where the high-frequency output part of a microwave oven magnetron is coupled to the waveguide of the microwave oven, the waveguide on the microwave oven side and the ground electrode on the magnetron side (metal part outside the magnetron tube body excluding the output antenna) In order to electrically connect between (outer periphery) into the through hole (inner periphery) of the magnetic yoke that surrounds the outside of the magnetron main body.Furthermore, when installing the magnetron on the waveguide on the microwave oven side, fit the protrusion on the periphery of the hole into the gasket. , so that good electrical contact can be obtained between each of the members.

However, since the above-mentioned highly conductive gasket is made by braiding thin copper wires, it is easily deformed, and even if the gasket is initially force-fitted into the metal cylinder, the fit between the gasket and the metal cylinder is There were problems such as the gasket becoming loose due to deformation and making the electrical connection unreliable, and in extreme cases, the gasket could become detached from its position or even fall off during transportation or handling of the magnetron. .

To solve this problem, conventionally, as shown in Fig. 2, a metal annular disk called a tip gasket base was inserted into the gap between the metal cylinder and the yoke through hole, and the metal cylinder was Countermeasures were taken such as making good electrical contact with the capacitor and inserting a gasket on top of it. In Fig. 2, 11 is the high-frequency output part of the magnetron (the lower end contains the end of an antenna connected to one resonator in a group of resonators formed on the inner surface of the anode cylinder), and 12 is the tube axis direction. 13 is a magnetic yoke that surrounds the outside of the magnetron body; 14 is a metal cylinder that supports the high-frequency output part via an insulating member (which serves as a ground electrode); 15 is a metal annular disk 16 is a gasket manufactured by braiding metal wires, and 17 is a waveguide leading to the food heating chamber of the microwave oven.

Furthermore, in Japanese Utility Model Publication No. 57-8135, the through hole of the yoke is formed to have a large diameter on the side near the magnetron body and a small diameter on the side near the waveguide, and a step is formed on the inner wall of the hole. In addition, a technique is described in which a stepped portion that engages with the stepped portion of the hole is formed on the outer periphery of the gasket to ensure the effect of preventing leakage of microwaves from the gasket portion. This structure also helps prevent the gasket from falling off.

[Problem to be solved by the invention] The above gasket-based countermeasure increases the number of parts,
Additionally, the gasket base must be in good electrical contact with the outer periphery of the metal cylinder, which requires high machining precision and must be handled carefully during assembly, which drives up costs.

In addition, making the inner wall of the yoke through hole a stepped surface would complicate the machining of the yoke, and the waveguide side mounting would engage the protrusion around the hole on the side facing the waveguide. Since the outer diameter of the gasket is small, installation may become difficult in some cases.

The present invention solves the conventional problems as described above, and ensures that the inner and outer peripheral surfaces of the gasket are in the desired position while maintaining good electrical contact with the outer peripheral surface of the metal cylinder and the inner peripheral surface of the magnetic yoke through hole. The object of the present invention is to provide a magnetron that can be held.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a permanent magnet that forms a magnetic field in the working space of the magnetron, and a magnetic circuit that is located outside the permanent magnet and surrounds the magnetron body. A plurality of cuts are provided around the metal cylindrical wall surface of the end of the metal cylinder, which passes through a through hole provided in the yoke, supports the high frequency output part via an insulating member, and serves as a ground side electrode. After fitting a highly conductive and elastic annular gasket that maintains good electrical contact between the cylinder and the through hole provided in the yoke into the gap between the cylinder and the through hole provided in the yoke, a gasket formed in the wall surface of the metal cylinder by the cut A plurality of protruding strips are bent outward to press down on the gasket and prevent the gasket from coming off.

[Function] By doing the above, it is completely prevented that the gasket leaves its original position and falls off, and the gasket used here, which is made of braided conductive metal wire, is relatively flexible. However, if the plurality of protruding strips formed on the wall of the metal cylinder are bent outward and pressed down so that they cannot be displaced, deformation becomes less likely to occur, and the outer periphery of the metal cylinder and the inner periphery of the yoke through-hole become less likely to occur. The state of electrical contact between the fitting portion and the fitting portion is also maintained satisfactorily.

[Embodiment] FIG. 1(a) is a perspective view showing the vicinity of a high frequency output section which is a main part of an embodiment of the present invention, and FIG. 1(b) is a side sectional view of the main part of the same embodiment. In the figure, reference numeral 18 denotes a plurality of protruding stripes formed by cutting around the wall surface of the metal cylinder at the end of the metal cylinder, and the other symbols are the same as those in FIG. 2. Figure 1 (
As shown in b), the protruding strip 18 formed at the end of the metal cylinder 14 is bent outward to press the gasket 16. In this way, the gasket 16 cannot be displaced and therefore the gasket and the metal cylinder 1
Both the electrical contact with the outside of the magnetic yoke 4 and the electrical contact with the inside of the through hole of the magnetic yoke 13 are maintained well.

[Effects of the Invention] As explained above, according to the present invention, the gasket cannot be displaced from its original position, and electrical contact between the gasket and adjacent members is maintained in good condition, making handling and transportation easier. It is also possible to prevent accidents such as the gasket falling off during the process.

[Brief explanation of drawings]

FIG. 1(a) is a perspective view showing the vicinity of the high frequency output section which is the main part of one embodiment of the present invention, FIG. 1(b) is a side sectional view of the main part of the same embodiment, and FIG. 2 is a conventional FIG. 2 is a side cross-sectional view showing the vicinity of a high-frequency output section of the magnetron. 11... High frequency output section, 12... Annular permanent magnet. 13...Magnetic yoke, 14...Metal cylinder that supports the high frequency output section via an insulating member, 15...Gasket base, 16...Gasket 517...Microwave oven waveguide, 18 ...Protruding stripes formed on the end of a metal cylinder.

Claims (1)

[Claims] 1. The high frequency output section is passed through a through hole provided in the permanent magnet that forms a magnetic field in the working space of the magnetron and the yoke that is located outside of the permanent magnet and forms a magnetic circuit surrounding the magnetron body, and the high frequency output part is connected to the insulating member. A plurality of cuts are provided around the wall surface of the metal cylinder at the end of the metal cylinder, which itself serves as a ground side electrode, and a plurality of cuts are provided in the gap between the metal cylinder and the through hole provided in the yoke to provide a good connection between the two. A magnetron characterized in that a plurality of protruding stripes formed on a metal cylindrical wall surface by the cuts are bent outward after a highly conductive and elastic annular gasket for maintaining electrical contact is fitted.