JPS6212639B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention attempts to collect all the electrical components to be cooled in one side chamber, limit the cooling space, and perform efficient cooling using a propeller fan.

Conventionally, the cooling structure of high-frequency heating devices, generally microwave ovens, mainly cools the magnetron, which generates the largest amount of heat, so it is placed immediately after the cooling fan to perform efficient blow cooling, and the remaining transformer and Many of the operating circuits relied on blow-cooling from a cooling fan. In other words, components such as transformers, magnetrons, and cooling fans have been arranged in series. The advantage of this configuration is that the magnetron can be cooled well, but on the other hand, blow cooling has a lot of loss during the process, and the cooling effect of the parts that are cooled by suction is much inferior to the former, and for this reason, transformers etc. have to have a fairly large diameter. It was customary to suppress the temperature rise by using a coil with a
Focusing on this point, the present invention realizes a structure in which all parts can be efficiently blown and cooled. The configuration of the present invention will be explained below with reference to the drawings.

FIG. 1 is a front perspective view of a microwave oven showing an embodiment of the present invention, FIG. 2 is a side view of the internal structure, FIG. 3 is a top view of the internal structure, and FIG. 4 is a back view of the microwave oven. 1
2 is a door, 2 is a heating chamber, and 3 is an operation panel, which is a so-called horizontal range in this embodiment. When the exterior 4 is removed, all the electrical components are concentrated on the rear of the operation panel and on the right side of the heating chamber, as shown in FIGS. 2 and 3. 5 is magnetron, 6
is a transformer, 7 is a capacitor, 8 is a propeller fan, 9 is its drive motor, 10 is a timer, 11
is an oven lamp, 12 is a latch switch, 13 is
is the door switch, 14 is the fuse box, 15 is
is a diode. In this way, all the electrical parts are gathered on the right side, and the upper wall 16 of the heating chamber is extended to the side of the exterior as shown in Fig. 3, and this machine room space is partitioned, so that the effect of the propeller fan 8 can be exerted. Ru. This point will be explained. The characteristics of a propeller fan are that it can obtain a large air volume, but it cannot obtain a high wind pressure, so parts with high air resistance are difficult to cool.On the other hand, parts with low resistance can be sent several times the air volume with a motor of the same capacity compared to a Sirotskov fan. be able to. In the example shown in Fig. 2, it is difficult for wind to enter the cooling fins of the magnetron, and the wind tends to escape toward the outer circumference of the propeller fan, where there is less resistance. Therefore, the extension of the heating chamber rear wall 17 and the upper wall 16 and the exterior 4
The bottom chassis 18 and the right side wall 19 of the heating chamber house the propeller fan 8 and the parts to be cooled in a closed chamber, thereby preventing the wind from escaping toward the outer circumference of the propeller fan and allowing air to be taken in through the intake hole 20. The cooled outside air can be directed straight to the parts to be cooled. In this embodiment, in order to effectively cool the magnetron, which has the largest air resistance, the propeller fan and magnetron are positioned facing each other, and the distance between them is brought close to each other by about 10 to 15 mm, and the rotation center C-C axis is aligned with the magnetron. It is removed from the cooling fin, and the outer periphery of the propeller fan, which has the highest wind speed, is placed opposite the cooling fin. This allows the use of a large-diameter propeller fan that provides a large amount of air. Furthermore, move the mounting plate 2 so as to lift the propeller fan upward.
1, the cooling effect of the magnetron is further enhanced. A guide 22 guides the exhaust gas from the magnetron into the heating chamber, and also serves as a cover for the lamp 11 in this example. The guide 22 is U-shaped with a vertical surface that diverts the flow of the magnetron's exhaust gas and directs it into the heating chamber. The upper horizontal plane is the upper wall 1
This is a flange for attaching to 6. The lower horizontal plane has a triangular shape and shields the magnetron exhaust ventilation path and the machine room space so that the magnetron's exhaust gas does not leak into the machine room space where electrical components are arranged. The attachment portion of the guide 22 to the upper wall 16 is pressed against the flange of the inclined upper wall 16, as shown in FIG. 3, and is fixed with one screw. One corner of the triangularly cut upper wall 16 also serves as a stop for the guide 22 to rotate.

Next, a cooling structure for the transformer 6 and other parts will be explained. The outside air taken in through the intake port 20 is naturally blown onto the transformer 6 and the condenser 7 as well. The air is then exhausted to the outside of the aircraft through a small hole provided in the standing wall 23 (a part of the bottom chassis 18) located almost directly below the right wall of the heating chamber. Therefore, the cooling resistance of these parts is extremely small, and therefore the transformer 6, the motor coil of the timer 10, the coil of the cooling fan motor 9, etc. are much better than conventional cooling, and can use wires with a thin diameter. Cost reduction is possible. Note that 25 is a heating chamber excessive temperature rise prevention device, which is attached to the heating chamber wall, but as shown in the figure, it is installed near the blowout of the fan, that is, on the heating chamber wall near the magnetron, to ensure good cooling. There is no malfunction during normal operation even at low temperatures. Therefore, an abnormality can be detected quickly and other parts can be prevented from being destroyed secondary. In addition to detecting abnormal overheating of the magnetron and fire in the heating chamber, it can also detect stoppages due to propeller fan failure.

The latch switch 12 is made of two insulation sheets 2.
6 (Fig. 2), which is sandwiched and fixed in a sandwich-like manner, which not only insulates the terminals but also prevents the switch case from cracking. 2
7 is an insulating tube which insulates the diode 15 and the capacitor case. The ground terminal 28 of the diode is fixed to the mounting plate 29 of the capacitor 7, so that the capacitor and diode can be treated as one unit. Because the atmosphere around both insulation sheets and tubes is low, there is little deterioration of insulation performance due to high temperatures. Also,
30 is a cooking indicator light 31 that converts the light of the oven lamp 11
This is a light conductor that guides the light, but it is mostly made of acrylic because of its translucency. Although acrylic is a resin that is easily deformed by heat, this does not pose any problem according to the present invention.

Next, we will discuss the exhaust structure for ventilation air guided into the heating chamber. Recently, wind-driven stirrer fans have come into widespread use due to their cost advantages.In consideration of such wind-driven stirrers, the small hole 32 is designed to be equipped with a method other than magnetron exhaust to increase the driving force. , which introduces air directly into the heating chamber from the propeller fan. 33 is a slit that blows ventilation air into the peephole 34 of the door after turning the stirrer. Air entering the heating chamber through the slit 33 is discharged to the outside of the main body through the exhaust guide 35. Here, the exhaust guide 35 is provided close to the intake hole 20 to ensure a reliable intake gap d at the intake hole 20 even if the main body is tilted and pressed against a wall (FIG. 3).

Finally, the door and its surroundings will be explained with reference to FIGS. 1 and 3. 36 is a handle; 37 is a key that moves up and down when the handle is operated and operates the latch switch 12 together with the operation of the cooking start switch 38;
9 is a door switch pin, 40 is a lever that magnifies the movement of the pin, 41 is an arm, and 42 is an arm pin that controls the movement of the arm. door switch 1
3 and the fuse box 14, the temperature usually rises significantly in the vicinity of the waveguide 43, and it is difficult to place components in such a position without using an expensive insulating material with a high allowable temperature. ,
According to the present invention, door switches and fuse boxes made of inexpensive materials can be used without any special consideration for such locations. Note that 44 is a power cord.

As described above, according to the present invention, the space to be cooled is limited, the propeller fan with low pressure and large air volume can fully demonstrate its characteristics, and a good cooling structure can be realized. In addition, since all the electrical parts are concentrated on one side, the lead wires can be shortened, allowing for easy and inexpensive wiring. As a matter of course, the service quality is also very good.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a high-frequency heating device showing an embodiment of the present invention, FIG. 2 is a perspective view showing the inside of the same side,
FIG. 3 is a top view of the same, and FIG. 4 is a rear perspective view of the same. 5... Magnetron, 6... Transformer, 8...
Propeller fan, 16...Heating chamber upper wall extension.

Claims (1)

[Claims] 1. A heating chamber that irradiates high frequency waves to the object to be heated, a magnetron that generates high frequency waves, a transformer that supplies high voltage to this magnetron, a cooling fan that has a propeller fan, and an intake hole and a first , a second exhaust hole, and an excessive temperature rise prevention device, the magnetron and the transformer are arranged centrally on one wall of the heating chamber, the rotating shaft of the fan is removed from the cooling fin of the magnetron, and the propeller is The outer periphery of the fan and the cooling fin are arranged to face each other, and the outside air taken in through the intake hole is blown onto the magnetron to cool it, and the exhaust gas is guided into the heating chamber and discharged to the outside of the aircraft through the first exhaust hole. In addition, the transformer is also cooled by blowing outside air taken in through the intake hole, and the exhaust air is discharged to the outside of the aircraft through a second exhaust hole provided near the transformer. A high-frequency heating device comprising the above temperature rise prevention device on the wall surface of the heating chamber.