JPH07109751B2 - Magnetron device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron device used for microwave heating equipment such as a microwave oven, and more particularly to a coupling structure of a magnetron and a frame-shaped yoke as an exciting circuit member thereof. is there.

2. Description of the Related Art Generally, a magnetron device used in a microwave oven or the like is constructed as shown in FIG.
The first pole piece 3 at one open end of the anode cylinder 2.
And a second magnetic pole piece 4 at the other open end. A microwave lead wire 6 having one end fixed to an anode vane 5 projecting from the inner peripheral surface of the anode cylinder 2 toward the tube axis extends to an output terminal 7, and the output terminal 7 is provided with an insulating ring 8 between them. The eyelet-shaped metal tube 9 connected by the above is sealed to one opening end of the anode cylinder 2 so that the flange portion 9a covers the first magnetic pole piece 3. Further, the eyelet-shaped metal tube 11 connected to the stem insulator 10 forming the cathode terminal has the second pole piece 4 at the flange portion 11a thereof.
Is sealed to the other open end of the anode cylinder 2 so as to cover.

The first annular permanent magnet 12 coaxially stacked on the flange portion 9a so as to surround the tubular portion 9b of the metal tube 9 magnetically couples one magnetic pole S to the first magnetic pole piece 3. The flange portion 1 has a relationship to surround the tubular portion 11b of the metal tube 11.
The second annular permanent magnet 13 coaxially stacked on 1a has one magnetic pole N magnetically coupled to the second magnetic pole piece 4. The frame-like yoke 14 that magnetically couples the other magnetic poles of the first and second annular permanent magnets 12 and 13 together connects the first yoke member 14a and the second yoke member 14b with a screw 15. And has a square cross-section and integrally surrounds the anode cylinder 2 and the first and second annular permanent magnets 12 and 13. The second yoke member 14b is provided with a through hole 16 for projecting the output terminal 7, and a projecting edge 16a formed around the through hole 16 to project.
Is in contact with the tubular portion 9b of the metal tube 9.

A large number of heat radiation fins 17 are attached to the outer peripheral surface of the anode cylinder 2 in multiple stages, and a metal shield case 18 is attached to the outer end surface of the first yoke member 14a.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional magnetron device thus configured, the microwave output radiated from the output terminal 7 is generated by inserting the top portion of the frame yoke 14 into the waveguide. , Is introduced into a heating chamber such as a microwave oven through the waveguide. And, there is a risk that a part of the microwave output leaks to the inside of the frame of the frame yoke 14 and leaks to the outside of the device because of the contact between the projecting edge 16a of the through hole 16 and the tubular portion 9b of the metal tube 9. Prevented by action.

However, in order to obtain such a shielding effect, the tubular portion 9b of the metal tube 9 becomes long and the position occupied by the insulating ring 8 becomes high, which makes it very difficult to meet the demand for miniaturization of the device.

In addition, when the protruding edge 16a of the through hole 16 is brought into contact with the tubular portion 9b of the metal tube 9, the elastic holding force with respect to the first annular permanent magnet 12 is reduced, and the permanent magnet 12 is displaced from the center. There is also a problem that the excitation efficiency is deteriorated due to the occurrence of a crack, and cracking due to thermal strain easily occurs.

Means for Solving the Problems In the present invention, an eyelet-shaped metal tube having a tubular portion connected to an output terminal via an insulating ring has a flange portion that covers the first magnetic pole piece in the anode tube. A magnetron sealed to the body, an annular permanent magnet stacked on the flange portion so as to surround the tubular portion, and one magnetic pole magnetically coupled to the first magnetic pole piece, A magnetron device comprising: a frame-shaped yoke formed in a square cross-section for magnetically coupling the other magnetic pole of the permanent magnet to the second magnetic pole piece of the magnetron, wherein Around the through hole formed so as to project the output terminal, there is an annular edge portion that projects toward the first magnetic pole piece in a U-shaped cross section and abuts the outer peripheral surface of the tubular portion of the metal tube. Also, the maximum of the annular part with the U-shaped cross section The inner peripheral surface of the permanent magnet is in contact with the outer peripheral surface.

With this structure, the annular edge portion formed around the through hole of the frame-shaped yoke protrudes toward the first magnetic pole piece side in a U-shaped cross section. Therefore, this edge portion and the metal tube of the magnetron The shield-acting portion formed by the contact with and is immersed in the frame of the frame-shaped yoke, and the total length of the magnetron device can be shortened accordingly. Further, in the case where the annular edge portion of the frame yoke is abutted on the metal pipe, the inner peripheral surface of the permanent magnet abuts the maximum outer peripheral surface of the annular portion of the frame yoke having a U-shaped cross section. The center deviation of the permanent magnet can be prevented and the excitation efficiency can be improved.

Example Next, an example of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the magnetron device according to the embodiment of the present invention has a cylindrical portion 21 connected to the output terminal 7 via an insulating ring 8.
The eyelet-shaped metal tube 21 having b surrounds the magnetron sealed to the anode cylinder 2 in a relation to cover the first magnet piece 3 at the flange portion 21a and the cylindrical portion 21b of the metal tube 21. In relation to each other, the annular permanent magnet 12 is stacked on the flange portion 21a, and one magnetic pole S is magnetically coupled to the first magnetic pole piece 3.
And a frame-shaped yoke 19 having a square cross section for magnetically coupling the other magnetic pole N of the permanent magnet 13 to the second magnetic pole piece 4. The frame-shaped yoke 19 projects around the through hole 20 for projecting the output terminal to the first magnetic pole piece 3 side in a U-shaped cross section and contacts the outer peripheral surface of the tubular portion 21b of the metal tube 21. In addition to having the annular edge portion 20a, the inner peripheral surface of the annular permanent magnet 12 is in contact with the maximum outer peripheral surface of the annular portion of the frame yoke 19 having a U-shaped cross section.

The magnetron device according to the embodiment of the present invention has a frame-shaped yoke.
By having an annular edge portion 20a around the through hole 20 of 19 and protruding toward the first magnetic pole piece 3 side in a U-shape in cross section and contacting the outer peripheral surface of the tubular portion 21b of the metal tube 21, Since the shield acting portion formed by the contact between the edge portion 20a and the metal tube 21 is located inside the frame of the frame yoke 19, the total length of the magnetron device can be shortened. Further, in addition to the structure, the permanent magnet 12 is provided on the maximum outer peripheral surface of the annular portion of the frame yoke 19 having a U-shaped cross section.
Since the inner peripheral surfaces of the permanent magnets are in contact with each other, the center deviation of the permanent magnet 19 can be prevented, and the excitation efficiency can be improved. Furthermore, since the inner peripheral surface of the permanent magnet 19 is held by the elastic force of the annular portion having a U-shaped cross section, thermal strain of the permanent magnet 19 is absorbed and cracking of the permanent magnet 19 due to thermal strain can be prevented. .

EFFECTS OF THE INVENTION As described above, according to the present invention, the total length of the magnetron device can be shortened, the center deviation of the permanent magnet can be prevented, and the excitation efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a magnetron device embodying the present invention, and FIG. 2 is a partially cutaway side view of a conventional magnetron device. 2 ... Anode structure, 3, 4 ... Pole piece, 7 ... Output terminal, 8
…… Insulation ring, 19 …… Frame-like yoke, 20 …… Hole, 21a …… Edge part, 21 …… Metal tube.

Claims (1)

[Claims] 1. An eyelet-shaped metal tube having a tubular portion connected to an output terminal via an insulating ring is sealed to an anode tubular body so that its flange portion covers the first magnetic pole piece. A magnetron and an annular permanent magnet, which is stacked on the flange portion so as to surround the tubular portion and magnetically couples one magnetic pole to the first magnetic pole piece, and the other magnetic pole of the permanent magnet. In a magnetron device comprising a frame yoke having a square cross-section for magnetically coupling to the second magnetic pole piece of the magnetron, the frame yoke includes:
Around the through hole for projecting the output terminal, there is provided an annular edge portion which projects toward the first magnetic pole piece side in a U-shaped cross section and abuts on the outer peripheral surface of the cylindrical portion of the metal tube. The magnetron device, wherein the inner peripheral surface of the permanent magnet is in contact with the maximum outer peripheral surface of the annular portion having a U-shaped cross section.