JPH0211971B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetron in which the number of protrusions provided on a yoke is reduced and the life of a press mold for forming a yoke is extended.

Figure 1 shows an example of a conventional magnetron.
2 is a yoke, 2 is an air cooling fin, 3 is a vertically long protrusion provided on the yoke, 4 is a round protrusion, 5 is an anode cylinder, 6 is a permanent magnet, 7 is a filter case, and 8 is an output terminal. The end of the fin 2 is divided into a plurality of parallel pieces, and in the one shown in the figure, the nearest piece of each fin is bent upward into a chevron shape, and the adjacent piece is bent downward into a chevron shape. The proximal piece of the bottom fin intersects the underfolded pieces of the three fins above it, and the pieces are positioned relative to each other.
A protrusion 4 is provided under the piece bent into a chevron shape under the lowest fin, and is in contact with the middle of the chevron shape of the fin piece. The vertical end of the piece bent into a chevron shape under the second fin from the bottom, which contacts the yoke, contacts the side surface of the vertically long protrusion 3. Under normal loads, the fitting between the fins 2 and the anode cylinder 5 will not loosen, but at high temperatures such as during overload, the coefficient of thermal expansion of the aluminum fins is usually higher than that of the copper anode cylinder. Since it is also large, there is a risk that the fin may fall downward. However, since there is a protrusion 4 below the bottom fin, it is supported by the protrusion 4 and does not fall. There are vertical parts at the fitting part with the anode cylinder and also at the ends of the fins to keep the fin spacing constant, so if the lowest fin does not fall, the three fins above it will also not fall. Also, the vertical end of the piece bent into a chevron shape under the second fin from the bottom that touches the yoke touches the side of the vertically long protrusion 3 (the side farthest from the viewer), so the fin is attached to the axis. There is no rotation (lateral shift) around the . Since each fin is positioned relative to the other as described above, the other three fins do not rotate either. However, such a conventional structure requires four protrusions for fixing the fins on one side of the yoke parallel to the anode cylinder axis. The yoke has holes for stopping cooling air ducts, installing temperature fuses, and installing thermostats, and also has many protrusions.
As shown in FIG. 2, there was a problem in that the life of the yoke-forming press mold was short. In the case of mass-produced magnetrons for microwave ovens, the lifespan of the press mold cannot be taken lightly from the standpoint of cost reduction.

An object of the present invention is to provide a magnetron in which the number of protrusions provided on the yoke is small and the life of a press die for forming the yoke is extended.

In order to achieve the above object, in the present invention,
One end of the divided piece of the lowest fin in the axial direction is in contact with the upper surface of the convexity of the yoke, and an adjacent piece of the same fin or a corresponding piece of the adjacent fin is in contact with the side surface of the same convexity. By preventing movement of the fins in the circumferential direction, the number of protrusions for preventing movement of the fins has been halved.

FIG. 3 is a diagram showing one embodiment of the present invention. The end of the closest piece bent into a chevron shape on the axially lowest fin is in contact with the upper surface of the protrusion 9 to prevent the fin 2 from falling even in the event of overheating. In this case, the fins are press-molded so that the burrings protrude upward, and when fitting the fins into the anode cylinder, the fins are pushed downward from above. Therefore, when in use, if the position is upside down as shown in Fig. 3, the protrusion 9 will not help prevent falling, but the bur ring will actually help prevent falling (the fins and anode cylinder If a large gap occurs between them, the heat of the anode cylinder will not be conducted to the fins,
At the station where the temperature of the fin decreases and thermal expansion decreases,
There is actually almost no gap between the fins and the anode cylinder, so the effect is sufficient to prevent the bur ring from falling). In addition, in the example shown in Fig. 3, the piece bent in a chevron shape under the second fin from the bottom touches the side surface (farthest from the plane of the paper) of the same protrusion 9, causing lateral deviation of the fin (the axial circumference rotation) is prevented. This is also useful for positioning the fins fitted into the anode cylinder when assembling them into the yoke when manufacturing the magnetron. FIG. 4 is an enlarged view of the main part of the embodiment, and in this example, the vertical end in contact with the yoke of the piece bent into a chevron shape under the lowest fin is in contact with the side surface of the protrusion 9. .

As explained above, according to the present invention, the protrusions can be used to prevent the fins from falling and to prevent the fins from slipping laterally.Therefore, the number of protrusions provided on the yoke can be halved, and the number of protrusions provided on the yoke can be reduced by half. life extension,
Helps reduce costs.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of a conventional magnetron, Fig. 2 is a diagram showing the outer surface of a yoke of a conventional magnetron, Fig. 3 is a diagram of an embodiment of the present invention, and Fig. 4 is an enlarged view of main parts of the embodiment. It is. 1...Yoke, 2...Wind cooling fin, 9...Protrusion provided on the yoke.

Claims (1)

[Claims] 1. Attach multiple air cooling fins perpendicularly to the axis of the anode cylinder, surround the outer periphery of the fins with a magnetic yoke consisting of sides parallel and perpendicular to the axis, and separate each fin into multiple parallel pieces except for the vicinity of the mounting part. The adjacent pieces of the same fin are alternately bent in opposite directions, and the corresponding pieces of each adjacent fin are bent parallel to each other in a chevron shape to position each fin relative to each other. In a magnetron in which the fins are prevented from moving by engaging with protrusions provided on sides parallel to the axis, one piece of the lowest fin in the axial direction is placed on the upper surface of the protrusion of the yoke, with an adjacent piece of the same fin or an adjacent piece of the adjacent fin. A magnetron characterized in that the corresponding pieces are in contact with the side surfaces of the same protrusion to prevent movement of the fins in the axial direction and the circumferential direction, respectively.