JPS5851163B2 - microwave oven - Google Patents

Description

[Detailed Description of the Invention] This invention provides an apparatus equipped with a hot air generator for browning, which uses blown air after magnetron cooling to efficiently cool the exterior plate around the hot air generator. The main purpose is to do something.

Conventional microwave ovens are equipped with a blower fan to cool the magnetron, and in addition to cooling the magnetron, blowing air after cooling the magnetron is introduced into the heating chamber and passed through the heating chamber. The front door glass is prevented from fogging up, the steam inside the heating chamber is discharged, and then the air is exhausted.

However, when the microwave oven is equipped with a hot air generator for browning, the air in the heating chamber is sucked into a duct with a built-in heater, heated to a temperature that allows browning, and then blown into the heating chamber again. When the hot air generator is in operation, if magnetron cooling air is blown into the heating chamber, the air temperature in the heating chamber is lowered by the cooling air, and the desired browning cannot be achieved.

Furthermore, the heater in the hot air generation duct generates extremely high temperature hot air for browning, which generates a large amount of heat.As a result, the exterior plate around the hot air generation duct becomes overheated, causing the cook to touch this exterior plate. There is a risk of getting burned if you touch it.

This invention has been made in view of this point, and one embodiment will be described below.

In Figures 1 and 2, 1 is the exterior of the microwave oven, 2 is the high-frequency heating chamber formed inside the exterior, 3 is the door, 4 is the operation panel, 5 is the magnetron, and 6 is the heating by high-frequency radio waves. A waveguide is introduced into the chamber 2, γ is an electric component for generating high voltage to drive the magnetron 5, and 8 is an electric component for generating a high voltage to drive the magnetron 5; 10 is a motor for driving the fan; 11 is a cold air duct for guiding the blown air after cooling the magnetron to the heating chamber 2; 12
13 is a heating chamber air intake hole for introducing blast air into the heating chamber 2, 13 is a heating chamber exhaust hole, 14 is a rubber pipe for leading out the exhaust gas exhausted from the heating chamber exhaust hole 13, and 15 is a heating chamber air intake hole from the rubber pipe 14. This is an exhaust cuctro to exhaust the exhaust gas to the outside of the microwave.

16 is a hot air guide duct having a hot air intake port 11 and a hot air blowing port 18 opened into the heating chamber 2; 19 is the duct 16;
The electric heater 20 built into the duct 16 is a hot air circulation fan built into the duct 16.

These 16, 19, 20, etc. form a hot air generator 21 for browning.

This browning is done by the hot air generator 21 in the heating chamber 2.
The air inside is heated to a temperature that allows browning and is discharged from the blowing port 18.

The hot air circulation fan 20 receives driving force from the motor 10 via a boolean IJ-22, a rubber belt 23, and a pulley 24.

25 is a small chamber formed to surround the hot air guide duct 16.

A small chamber intake port 26 communicating with the cold air duct 11 and a small chamber exhaust port 21 for discharging the cooling air after passing through the small chamber 25 are formed in the wall of the small chamber 25 .

The air passage for cooling the hot air guide duct 16 is narrowed by the small chamber 26, and the cooling air inside the small chamber 26 flows smoothly and quickly, so that the heat released from the wall of the hot air guide duct 16 is efficiently exhausted to the outside.

Furthermore, by providing the wall of the small chamber 25, the space between the heating chamber 2 and the outer device is double insulated, and therefore the amount of heat transferred from the hot air generator 21 to the outer device plate is reduced, preventing abnormal overheating of the outer device plate. It can be prevented.

2B is an air path switching device disposed near the heating chamber intake hole 12 and the small chamber intake port 26 for selectively switching the air passage after cooling the magnetron to the heating chamber 2 side or the small chamber 26 side.

The damper 2'9 of the air path switching device 28 is pivotally supported on the wall of the heating chamber 2 at one end, and comes into contact with the opening upper end or the opening lower end of the cold air duct 11 at the other end. By switching the air path.

When the damper 29 is located at the upper end of the opening as shown by the solid line, cooling air is sent into the heating chamber 2 side.

On the other hand, when it is located at the bottom edge of the opening as shown by the dotted line,
Cooling air is sent to the small chamber 25 side.

The air path switching device 2B is further equipped with an electromagnet (not shown) for rotating the damper 29, and the like.

The technique of switching the damper 29 using an electromagnet is a commonly used technique and can be easily constructed, so it will not be particularly explained.

A switch (not shown) for controlling the energization of the electromagnet and switching the damper 29 may be provided on the microwave operation panel section 4 so as to be manually switched. It may be formed so that it can be switched in conjunction with (no).

The air path switching device 28 is located at a position where cooling air is sent to the small chamber 25 side when the hot air generator 21 for browning is in operation, and where the cooling air is sent to the heating chamber 2 side when only high frequency heating is being performed. are respectively switched to the positions where they are sent out.

This invention is constructed as described above, and a small chamber surrounding the hot air guide duct is formed, and the blown air after being cooled by the magnetron is allowed to pass through the small chamber, so that the air path for cooling the hot air guide duct is Since the cooling air inside the small chamber is narrowed by the small chamber and flows smoothly and quickly, the heat emitted from the hot air guide duct wall is efficiently discharged to the outside.Furthermore, the air passage after magnetron cooling can be selected to the heating chamber side or the small chamber side. Since it is equipped with an air path switching device to switch the cooling air path to the heating chamber side during high-frequency heating, the cooling air path can be switched to the heating chamber side to discharge steam in the heating chamber, and when heating for browning, the cooling air path can be switched to the heating chamber side. By switching to the small chamber side, the cooling air is not blown into the heating chamber, so the hot air temperature can be maintained at a high temperature for browning.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention seen from the front, and FIG. 2 is a block diagram of the same embodiment seen from the plane with the exterior plate and chamber wall removed. 2...High frequency heating chamber, 5...Magnetron, 8...Blower fan, 16...Hot air guide duct, 19...Heater, 25...
...Small room, 2B... Air path switching device.

Claims (1)

[Claims] 1. A magnetron, a blower fan for cooling the magnetron, a heating chamber through which the blowing air after cooling the magnetron is introduced and passed through, and the air in the heating chamber is sucked into a hot air guide duct with a built-in heater for browning. and a hot air generator for browning by heating the hot air to a possible temperature and blowing it into the heating chamber again, forming a small chamber surrounding the hot air guide duct and cooling the small chamber with a magnetron. What is claimed is: 1. A microwave oven characterized in that it is equipped with an air passage switching device for selectively switching the air passage after cooling the magnetron to the heating chamber side or the small chamber side.