JPS6293833A - Radiator for magnetron - Google Patents

Abstract

PURPOSE:To construct fins having good radiation performance by folding the side section of a radiation fin parallel with the air flow while arranging a plurality of band type raising sections, where the sides facing against the air flow are raised and opened on the radiation fin around the side and the rear section of the anode side section, and fixing them to the folded side section of the fin. CONSTITUTION:Since raising sections 11 are provided, the pressure loss of the air flow passing through said sections 11 will increase while simultaneously the air flow will decrease thereby the wind flow at the section provided with no raising sections 11 will increase correspondingly. Consequently, the air flow toward the center of a radiation fin 9 is induced gradually at the rear stream side of an anode or a fin collar thus the dead water area 13 reduces considerably. Since the foot part of the raising section 11 has obliquely constructed joint side 14 to provide an elevation angle against the air flow, the air flow will vary abruptly at the foot part to cause turbulence, increasing the heat conductivity. While since the raising sections 11 are connected to the side section 10 of the fin, the efficiency of fin radiation is improved, lowering the entire thermal resistance of the fin 9 resulting in reduction of the temperature nonuniformity around the anode.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a radiation fin for a high frequency generator used in a high frequency cooking device or the like.

BACKGROUND ART Conventionally, such a high frequency generator (hereinafter abbreviated as magnetron) mainly consists of an antenna 11, a magnet 2aT2b, an anode 3, and a radiation fin 4, as shown in FIG.
, yoke 5. The input electricity is converted into electromagnetic waves inside the anode 3 and emitted from the antenna 1, and the electromagnetic waves heat and cook the food. However, some of the input electricity is not converted into electromagnetic waves and is generated as heat, causing the anode 3 to reach a high temperature. Cool by letting outside air flow in.

FIG. 3 shows a perspective view of one such radiation fin 4. As shown in FIG. Generally, the radiation fins 4 are made of metal such as aluminum or copper, and are fitted to the anode 3. Heat generated by the anode 3 is transmitted from the fin collar 5 to the fins 4, but outside air 6a is placed between the fins 4. is flowing, heat exchange occurs between the fin 4 surface and the airflows 8b and 6C, and as a result, the heat generated at the anode 3 is transferred to the airflow 8b.
.

6C and the anode 3 will be cooled.

Problems to be Solved by the Invention As mentioned above, the heat dissipation fin dissipates the heat generated in the anode to the outside air and cools the anode, but since the airflow is branched left and right by the anode, A large water stop area (hatched area 7 in FIG. 3) is created on the downstream side of the anode.

This water stop area is an airflow retention area, and heat is difficult to be released from the radiation fin surface, resulting in a high temperature. This not only deteriorates the efficiency of dissipating heat generated from the anode, but also causes a temperature distribution of several tens of degrees in the circumferential direction of the anode, causing thermal distortion in the anode. Currently, this thermal strain not only increases the contact thermal resistance between the radiation fins and the anode, but also shortens the life of the magnetron.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention bends the side portions of the radiation fins that are parallel to the airflow, and also bends the sides of the radiation fins that are parallel to the airflow from the anode side to the rear radiation fins, facing the airflow. A plurality of belt-shaped cut-and-raised sides with cut-raised and open sides are provided,
Further, the cut and raised portion is configured to be joined to the bent side portion of the fin.

The present invention uses the method described above to reduce the cut-off area on the downstream side of the anode of the magnetron, increase the heat transfer coefficient in the downstream area of the anode by the boundary layer leading edge effect, and increase the amount of heat dissipated from the entire heat dissipation fin. At the same time, it also equalizes the temperature of the anode outer wall and reduces thermal distortion of the anode.

EXAMPLE The present invention will be explained below according to an example of the present invention shown in FIG.

FIG. 1a is a perspective view of one radiation fin of the magnetron device according to the present invention, and FIG. 1b is a cross section XX.

In FIG. 1, a heat dissipating fin 9 made of aluminum, copper, etc. has a bent side 1Q parallel to the air flow 12, and a plurality of band-shaped parts having a joint side 15 on the side 1o. A cut-and-raised portion 11 is provided. This cut-up 11
The other joint side 14 is configured to be oblique to the airflow direction, and the cut and raised rhyme also has an angle of attack with respect to the flow. Further, the cut and raised portion 11 is configured so that as the air flows downstream, the length of its two open sides, that is, the cut side facing the airflow, gradually becomes longer.

Since the raised cut 11 is provided in this way, the pressure loss of the air flow passing through the raised cut 11 increases, and at the same time, the air flow rate decreases. Air volume increases. As a result, an airflow is gradually induced toward the center of the radiation fins 9 on the downstream side of the anode (not shown) or the fin collar 8, and the cutoff area 13 is significantly reduced. Also, cut and raise 1
Since the joint side 14 of the leg section 1 is formed obliquely and has an angle of attack with respect to the air flow, a sudden change in the flow occurs at the leg section, causing turbulence 'i'1. and increase the heat transfer coefficient.

Due to this increase in heat transfer coefficient and the increase in heat transfer coefficient due to the leading edge effect of the cut and raised boundary layer, the surface thermal resistance of the radiation fins 9 downstream of the anode is greatly reduced. On the other hand, since the cut and raised portions 11 are connected to the side portions 10 of the radiation fins, the fin efficiency is high. This lowers the overall thermal resistance of the fins 9 and reduces temperature unevenness around the anode. In this embodiment, as shown in FIG. 1, the cut-and-raised portions 11 are formed only in one direction of the radiation fins 9, and are arranged parallel to the radiation fins 9. However, various modifications of this shape are possible. Figure 2a,
b and c show cross sections at the same position as the XX cross section in FIG. 1 for other embodiments. Figure 2 a'
1a+11a' is cut and raised, and the upper and lower sides of the radiation fins are provided. This makes it possible to effectively utilize the space created between the lowermost and uppermost radiation fins and the magnet. The cut-and-raised portions 11b and 11b' are provided so as to be slightly offset toward the downstream side, and it is possible to avoid the waiter caused by the front cut-and-raised portion, thereby improving the heat transfer coefficient. C is a twisted cut-and-raised 110, which induces a vortex and has an effective heat transfer coefficient. Obtainable.

In the above embodiment, the thermal resistance of the fins is reduced more than in the first embodiment, so that the anode temperature can be lowered and thermal distortion can also be reduced.

Effects of the Invention As described above, the magnetron device of the present invention bends the side portion parallel to the airflow, and provides a plurality of band-shaped cut and raised portions on the radiation fins downstream of the anode so as to be connected to the side portion. ■ Air flow is induced to the anode stop area, increasing the effective heat dissipation area. ■The heat transfer coefficient on the fin surface increases due to the boundary layer leading edge effect. ■Fin efficiency increases due to the circulation of heat to the sides. As a result, it is possible to construct a heat dissipation fin with good heat dissipation performance, and the temperature unevenness around the anode is reduced.
This not only makes it possible to reduce thermal distortion caused by temperature unevenness and extend the life of the anode, but also makes it possible to obtain a highly efficient magnetron device.

[Brief explanation of drawings]

Fig. 1a is a perspective view of an embodiment of a heat dissipation fin for a magnetron according to the present invention, Fig. 1 is a XX sectional view of Fig. 1a, Fig. 2a
, b, and c are respectively sectional views of heat dissipating fins for magnetrons according to other embodiments of the present invention, FIG. 3 is a perspective view of a conventional example of heat dissipating fins for magnetrons, and FIG. 4 is a front view of the same magnetron. be. 1... Antenna, 3... Anode, 4
．． 9... Heat dissipation fin, 11... Cut and raise. Name of agent: Patent attorney Toshio Nakao and one other person B-
--Beautiful- 11-Kirishikoshikui) Figure 2//b (C) Figure 3 3--Red 4/---Antenna? --- Insect stone 3 --- Anode 4 -- One side η heat pin 5 --- Yo 7

Claims (3)

[Claims] (1) The sides parallel to the airflow of multiple parallel plates attached perpendicular to the cylindrical anode are bent, and from the anode side to the rear, two sides facing the airflow are open and the other sides are parallel. A radiator for a magnetron, wherein a plurality of band-shaped cut and raised parts are provided to be joined to a plate, and one of the joining sides of the cut and raised parts is provided on the bent side part. (2) The heat radiator for a magnetron according to claim 1, wherein the cut-and-raised opening side gradually becomes longer as it goes downstream. (3) The heat radiator for a magnetron according to claim 1, wherein one of the joint portions of the cut and raised joints is configured to be oblique to the airflow direction.