JPH0233831A - Magnetron - Google Patents

Abstract

PURPOSE:To heighten utilization efficiency of a yoke material for the purpose of lightening by forming the mounting holes on a yoke without impairing a magnetic circuit. CONSTITUTION:Bottomed cylindrical mounting holes 12 are formed on the side of a yoke piece 9 being deformed by swelling out toward the inside of a yoke 8, while the bottomed mounting holes 15 are formed on the side of the yoke piece 9 being deformed by swelling out toward the inside of the yoke 8. Then, the mounting holes 12 and 15 do not disturb passage of a magnetic flux so that a magnetic circuit can be constituted by effective utilization of a yoke material.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetron, and more particularly to an improved structure of a magnetic circuit.

(Explanation) Conventionally, this type of magnetron has been constructed by disposing annular magnets at both ends of the oscillating tube body in the tube axis direction, surrounding the oscillating tube body and the magnets with a frame-shaped yoke, and constructing a magnetron consisting of the magnet and the yoke. A device configured to apply a magnetic force of a certain value or more to the oscillator tube body using a magnetic circuit is known, for example, from Japanese Utility Model Publication No. 58-40520. When assembling into a device, mounting holes are drilled for fixing device parts such as ventilation ducts and thermoswitches with screws, but multiple mounting holes are drilled because the mounting positions of the components differ depending on the device.

As part of the magnetic circuit, the yoke needs to have a cross-sectional area that corresponds to a predetermined amount of magnetic flux in order to apply a magnetic force of a certain value or more to the oscillator body. Because the magnetic circuit was designed with the possibility of parts missing, the yoke material was used inefficiently, making the magnetron heavier and more expensive.

(c) Problems to be Solved by the Invention The present invention was made to solve the above-mentioned drawbacks, and an object of the present invention is to provide a magnetron that can be made lighter and less expensive by improving the utilization efficiency of yoke material. shall be.

(d) Means to solve the problem The mounting hole is formed in the yoke without damaging the magnetic circuit.

(4) Function: Since a part of the magnetic circuit is not lost due to the mounting hole, the yoke material can be used effectively and the magnetic circuit can be constructed with less material than before.

(F) Embodiment An embodiment of the present invention will be described below in detail with reference to FIGS. 1 to 5.

(1) is the oscillation tube body, which includes a cylindrical anode body (2), an output antenna (3) protruding from one end of the anode body, and a cathode stem (4) protruding from the other end of the anode body (2). It is composed of. (5> is a plurality of cooling fins press-fitted to the outer periphery of the anode body (2>), and a plurality of tongue pieces (6) are attached to the ends.
is formed. (7) is an annular permanent magnet disposed around the output antenna (3) and the cathode stem (4);
(8> represents the main body (1), the cooling fins (5) and the magnet (
The magnet (7) and the yoke (8) constitute a magnetic circuit that applies a magnetic force of -a certain value or more to the main body (1), and the yoke (8) has a cross section omitted. A U-shaped first yoke piece (9), the first yoke piece (9) and a screw (
10> A fixed second yoke piece (11).

(12) is a bottomed cylindrical attachment hole formed on the side surface of the first yoke (9) by press working to bulge inward to the yoke (8), and is generated by a blower (not shown). A ventilation duct (13) that guides the cooling air into the yoke (8) is fixed with screws (<14), and multiple mounting holes (12) are formed to accommodate the types of equipment to be incorporated. has been done. (15) is the first yoke piece (9)
The thermoswitch (16) is fixed with a screw (17) through a bottomed cylindrical mounting hole formed on the side by bulging and deforming toward the inside of the yoke (8) by press processing. A plurality of mounting holes (15) are also formed to correspond to the type of equipment to be incorporated. The cooling fins (5
As shown in FIG. 5, the tongue piece (6) of ) has its side end in contact with or close to the mounting holes (12) and (15) for positioning during assembly.

(18) is a choke coil connected to the cathode node (19) protruding from the cathode stem (4); (20) is a shield case surrounding the cathode stem (4) and the choke coil (18); (21) is the choke coil (
capacitor connected to the shield case (2).
0> is penetrated and supported.

Therefore, the ventilation duct (13) and the thermo switch (16)
) is fixed to the side surface of the yoke (8) by screwing the screws (14, 17) into the mounting holes (12, 15) from the outside of the yoke (8).

The mounting holes (12) and (15) are bulged and deformed into a cylindrical shape with a bottom, and are not cut out like in the past, so the mounting holes (12) and (15) prevent the passage of magnetic flux. By effectively utilizing the yoke material, it is possible to construct a magnetic circuit equivalent to the conventional one with less material than the conventional one. Therefore,
The magnetron can be made lighter and cheaper.

Figures 6 and 7 show the second embodiment, in which (22) is a ventilation duct (13) formed by deformation by press working on the side of the first yoke (9) for fixing screws (14). The mounting hole <23) is formed by pressing the thermoswitch (16) screw (1) on the side of the first yoke (9).
7> Mounting holes for fixing, the mounting holes (22) and (23) each have a pair of notches (
22a ) (23a ) and the notch (22a ) (2
37) and curved portions (22b) and (23b) curved toward the inside of the yoke (8).

Therefore, the ventilation duct (13) and the thermo switch <16
) are the pair of notches (22a) (22a) (2
3a) It is fixed by screwing together while tapping between the edges.

A pair of notches (22a) and (23a) are formed in the mounting holes (22) and (23) of this second embodiment approximately parallel to the passing direction of the magnetic flux, and a curved portion (22a>(23a)) is formed between the notches (22a>(23a)). 22b) (23b), the passage of magnetic flux is almost not obstructed by the mounting holes (22) and (23), and a continuous magnetic circuit can be constructed, making effective use of the yoke material. A magnetic circuit equivalent to the conventional one can be constructed using fewer materials.

Figures 8 and 9 show the third embodiment, in which (24) is a ventilation duct (13) formed by deforming by press working on the side of the first yoke (9) for fixing screws (14). The mounting hole (25) is a thermoswitch (16〉screw (1
7) Attachment holes for fixing, the attachment holes (24) and (25) are cut out (24a) and (25), respectively, approximately parallel to the passing direction of the magnetic flux.
5a), and these notches (24a) (25a)
It is formed by bulging and deforming both sides toward the inside of the yoke (8).

Therefore, the ventilation duct (13) and the thermo switch (16)
) are the notches (24a)(
25a) It is fixed by screwing the screws (14) and (17) into the periphery of the hole formed by deforming both sides.

The mounting holes (24) and (25) of this second embodiment are formed with cuts <24a) and (25a) approximately parallel to the direction of passage of magnetic flux, and the cuts (24a and 25a) are bulged and deformed on both sides. The mounting holes (24) (25)
The passage of magnetic flux is hardly obstructed by
A continuous magnetic path can be constructed, and by effectively utilizing the yoke material, a magnetic circuit equivalent to the conventional one can be constructed with less material than the conventional one.

(G) Effects of the Invention As described above, according to the present invention, the passage of magnetic flux is almost not obstructed by the mounting hole, and a continuous magnetic circuit can be constructed, and the yoke material can be effectively used, requiring less material than before. It is possible to construct a magnetic circuit equivalent to the conventional one. Therefore, the magnetron can be made lighter and cheaper, etc.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is a sectional view of the same, FIG. 3 is a perspective view of the yoke, and FIG. 4 is a sectional view of the same essential parts.
5 is a plan view of the same essential parts, FIG. 6 is a perspective view of the yoke of the second embodiment, FIG. 7 is a sectional view of the same essential parts, and FIG. 8 is a perspective view of the yoke of the third embodiment. FIG. 9 is a sectional view taken along line IX-IX in FIG. (1)... Oscillator tube body, (7)... Annular magnet, 8
)... Yoke, (13)... Ventilation duct, (16
)...Thermo switch, (12) (15), (22)
(23), <24) (25)...Mounting hole.

Claims (1)

[Claims] (1) In a magnetron in which an annular magnet is coaxially disposed on an oscillation tube body and a frame-shaped yoke surrounds the body and the magnet, parts necessary for installing the magnetron in a device such as a microwave oven are fixed with screws. A magnetron with mounting holes formed in the yoke that makes up the magnetic circuit without damaging the magnetic circuit.