JPS61237337A - Magnetron device - Google Patents

Abstract

PURPOSE:To suppress demagnetization by high temperature of ferrite magnet and prevent damage of ferrite magnet by providing a projected portion located in the heighborhood of ferrite magnet by bending, in the form of V-character or U-character, a part of horizontal wall of frame type yoke into the internal side of frame and causing this projected portion to be in contact with cooled air flow. CONSTITUTION:Since a frame type yoke 8 operates as a heat radiating wing for ferrite magnets 5, 7 and the surface area of frame type yoke 8 is enlarged by the projected portions 9a, 9b, 10a, 10b formed in the form of character V, it becomes possible to suppress temperature rise of ferrite magnets 5, 7 and reduce the size of heat radiating fin without enlargement in external size of frame type yoke 8. Moreover, since the projected portions 9a, 9b, 10a, 10b give the cushion effect in the substantial axial direction of the frame type yoke 8, damage by tightening in the axial direction of ferrite magnets 5, 7 can be prevented. In addition, since a pair of projected portions 9a, 9b collide with the ferrite magnet 5 while a pair of projected portions 10a, 10b with the ferrite magnet 7, respectively from both sides, the ferrite magnets 5, 7 can be positioned easily at the time of assembling and displacement after assembling can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetron device consisting of a magodron and excitation means coupled thereto.

BACKGROUND OF THE INVENTION In general, an annular ferrite magnet is used as the excitation means of a magnetron device for a microwave oven, and this magnet is placed on a pole piece located at one end of the pole body of the magnetron. On the other hand, since the magnetron has a large anode loss of several hundred watts, the temperature of the ferrite magnet increases during operation of the device, and there is a risk of irreversible demagnetization (hereinafter referred to as high-temperature demagnetization). Therefore, a large number of heat radiation fins are attached in multiple stages to the outer peripheral surface of the anode cylinder, and a forced air cooling airflow is circulated between the heat radiation fins. The problem was that it was difficult.

Furthermore, since ferrite magnets are relatively fragile, there was a risk of damage due to thermal expansion of the anode cylinder when the annular ferrite magnets stacked on the magnetic pole pieces were tightened with a strong frame-like yoke.

Problems to be Solved by the Invention Accordingly, an object of the present invention is to provide a highly efficient magnetron device that can further suppress high-temperature demagnetization of ferrite magnets and prevent the aforementioned damage to ferrite magnets. There is a particular thing.

Means for Solving the Problems According to the present invention, a portion of the horizontal wall of the frame-shaped yoke is bent inward into the frame in a V-shape or U-shape to have a protrusion located next to the ferrite magnet. , a cooling air stream is brought into contact with this protrusion.

Effect: With this configuration, the surface area of the frame-shaped yoke that also serves as a heat dissipation blade for the ferrite magnet, that is, the area that comes into contact with the forced air cooling air flow, is increased, and the temperature rise of the magnet can be suppressed to that extent. Further, since the protrusion provides a cushioning effect on the substantial axial length of the frame-shaped yoke, the above-mentioned damage to the ferrite magnet can be prevented.

Embodiment As shown in FIG. 1, a large number of heat dissipating fins 3 attached to the outer peripheral surface of the anode cylinder 2 of the magnetron 1 are arranged in multiple stages so that a flow path for forced air cooling is created between the fins. has been done. A first annular ferrite magnet 5 is coaxially arranged on a first magnetic pole piece 4 provided at one end of the anode cylinder 2, and one magnetic pole is magnetically coupled to the first magnetic pole piece 4. has been done. Further, a second annular ferrite magnet 7 is coaxially arranged on the second magnetic pole piece 6 provided at the other end of the anode cylinder 2, and one magnetic pole is attached to the second magnetic pole piece 6. are connected to each other. Then, the anode cylinder body 2, the radiation fins 3, and the first. The other magnetic poles of the first and second annular ferrite magnets 5, 7 are magnetically coupled by a frame-shaped yoke 8 surrounding the second annular ferrite magnets 5, 7.

The frame-shaped yoke 8 includes a first member 9 having an opening-shaped cross section and a second member 9 having a cross-sectional shape.
In addition to member 1o, both members 9 and 1° are integrally connected by screws 11 so as to have a cross-sectional shape. Then, a portion of the two horizontal walls of the frame-shaped yoke 8 in a plane perpendicular to the tube axis is bent in a figure 7 shape toward the inside of the frame to form a pair of protrusions 9a.
, sb and a pair of protrusions 10 a and 10 b are formed.

As shown in FIG. 2, the pair of protrusions 9a and 9b are pressed into two strips parallel to both side walls, and are located on both sides of the annular ferrite magnet 5, and are located on the outer surface of the seven-piece light magnet 5. is in contact with A pair of protrusions 10 a and 10 b are also formed in the same manner as described above, and are located on both sides of the annular ferrite magnet 7 and in contact with the outer surface of the ferrite magnet 7 . A forced air cooling airflow sent out from a fan of a blower (not shown) flows in one direction perpendicular to the plane of the paper so as to be in contact with the radiation fins 3 and the frame-shaped yoke 8.

In the magnetron device configured in this manner, the frame-shaped yoke 8 also serves as heat dissipation blades for the ferrite magnets 5, 7, and the surface area of the frame-shaped yoke 8 is formed by protrusions 9a, 9b formed in a figure 7 shape. , 1oa, 1ob, so
It is possible to reduce the size of the heat dissipation fins that suppress the temperature rise of the ferrite magnets 5.7 without increasing the external size of the frame-shaped yoke 8. In addition, the protrusions 9a, 9b, 1
0a.

10b provides a cushioning effect to the substantial axial length of the frame-shaped yoke 8, thereby making it possible to prevent the ferrite magnets 5, 7 from being damaged due to internal tightening in the axial direction. Furthermore, a pair of protrusions 9a and sb are provided on the ferrite magnet 5, and a pair of protrusions 10 are provided on the ferrite magnet 5.
Since the magnets a and 10b abut on the ferrite magnet 7 from both sides, it is not only easy to position the ferrite magnets 5 and 7 during assembly, but also to prevent misalignment after assembly.

In the embodiment described above, the protrusions 9a, 9b, 10a, and 10b were bent in a 7-shape, but they may also be in a U-shape. Moreover, protrusions 9a, 9b, and 10a.

10b may not be in contact with each of the ferrite magnets 5, 7, and may be formed only on either one of the two horizontal walls. Furthermore, it goes without saying that the present invention is equally applicable to a type of device that does not have either the first or second annular ferrite magnet.

Effects of the Invention Since the present invention is configured as described above, it is possible to suppress high-temperature demagnetization caused by a rise in the temperature of the ferrite magnet and to downsize the radiation fins without increasing the external size of the frame-shaped yoke. Not only is this possible, but it is also possible to prevent damage to the ferrite magnet due to axial wire fitting.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view of a magnetron device embodying the present invention, and FIG. 2 is an exploded perspective view of essential parts of the device. 1... Magnetron, 2... Anode cylinder, 3...
−・・・Radiation fin, 4.6・・・Magnetic pole piece, 5
, 7... Ferrite magnet, 8... Frame-shaped yoke, 9a, 9b, 10a. 1ob...protrusion. Name of agent: Patent attorney Toshio Nakao and one other person

Claims (1)

[Claims] A ring-shaped ferrite magnet is coaxially arranged on the first magnetic pole piece of a magnetron, which has a large number of radiation fins attached in multiple stages on the outer peripheral surface of an anode cylinder, and one magnetic pole of the magnet is magnetically attached to the first magnetic pole piece. At the same time, the other magnetic pole of the magnet is magnetically coupled to the other magnetic pole piece of the magnetron by means of a frame-shaped yoke surrounding at least the anode cylinder, the radiation fin, and the magnet, and the air is sent out from the fan of the blower. In the magnetron device that distributes the forced air cooling airflow between the heat radiation fins, a part of the horizontal wall of the frame-shaped yoke is bent inside the frame in a V-shape or a U-shape and is positioned next to the magnet. 1. A magnetron device comprising a protrusion that causes a portion of the airflow to come into contact with the protrusion.