JPH0554967A - Microwave oven - Google Patents

Abstract

PURPOSE:To enhance the low output power heating performance by allowing electric waves to be radiated only to the irradiation part provided in the upper part of a heating chamber when the heater output is held small. CONSTITUTION:When the heater output is held below 50%, a rotary antenna 2 and a magnetron 3a installed in the upper part of a heating chamber are solely operated by a control relay. The heater output is adjusted by increasing or decreasing the operating time in steps. When the heater output exceeds 50%, another magnetron 3b and a turntable 7 are operated simultaneously. The output is adjusted by operating an upper and a lower irradiation part alternately and by increasing or decreasing the operating time. Thereby low output power heat emission can be made effectively by performing agitation with the agitating action of electric waves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating control structure for a microwave oven.

[0002]

2. Description of the Related Art As a microwave oven, there is a microwave oven having radio wave emitting portions at the upper and lower portions of a heating chamber so that heating can be performed with high output and efficiently. In such a microwave oven, as shown in FIG. 5, output heating is basically performed by alternate radiation from both upper and lower radiation portions at any output level.

[0003]

However, when the low power heating corresponding to the levels 2 to 5 shown in FIG. 5 is performed by the alternating radiation of the upper and lower radiation portions as described above, the radiation is performed from the lower radiation portion. The radio waves were not efficiently agitated by the stirrer fan and the rotating antenna above the heating chamber, and as a result, they were heated only by the radio waves from the upper radiating part, which caused uneven heating.

The present invention has been made in view of the above problems, and it is an object of the present invention to enhance the low output heating performance in a microwave oven having radio wave irradiating portions in the upper and lower portions of a heating chamber.

[0005]

According to the present invention, radio wave radiating portions are provided in the upper and lower portions of the heating chamber, an electric wave stirring mechanism is provided in the upper portion of the heating chamber, and a turntable is provided in the lower portion. In the microwave
When the heating output is reduced, the heating control means is provided for heating only by the radiation of the radiation part in the upper part of the heating chamber.

[0006]

According to the present invention, when the heating output is reduced, the heating is performed only by the radiation of the radiating portion in the upper part of the heating chamber, whereby the low output heating is always performed by the radio wave agitated by the radio wave agitation mechanism. It is done efficiently.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below. FIG. 1 is a simplified block diagram of the microwave oven of the present invention.

Reference numeral 1 denotes a heating chamber. Inside the heating chamber 1, there is provided a turntable 7 on which food S is placed and rotated.
A rotary antenna 2 is provided on the upper part, which is a radio wave agitating mechanism and whose tip serves as a radio wave radiation part. 3a, 3b
, Each of which is a magnetron, and a radio wave generated by an upper magnetron 3a is transmitted to the rotary antenna 2 through the upper waveguide 5a and radiated from the tip thereof.
The radio wave generated by the lower magnetron 3b is radiated from the opening 10 as a radiating portion that opens at the bottom of the heating chamber 1 through the lower waveguide 5b.

FIG. 2 is a circuit configuration diagram. 20a is a first power supply circuit of the magnetron 3a, and 20b is a second power supply circuit of the magnetron 3b. Control as heating control means constituted by a microcomputer. Part 21
When the first control relay 24 driven by is turned on, the magnetron 3a and the motor 25 of the rotary antenna 2 in parallel therewith are operated, and when the second control relay 26 is turned on, the magnetron 3a is turned on. Three
b and the motor 27 of the turntable 7 in parallel therewith are operated. Reference numeral 30 is a power source, and 31 is a blower motor for cooling the magnetrons 3a and 3b.

The heating control operation will be briefly described below with reference to the flowchart of FIG. When a desired operation command is issued and the heating output is 50% or less, only the first control relay 24 is driven and only the magnetron 3a and the rotary antenna 2 are operated (steps 1, 2, 3). .. This actual operation is, for example, 1 to 5 levels as shown in FIG. 4, and the magnetron 3a and the rotary antenna 2 are continuously operated at the 5th level, and discontinuously operated at the 4th level or lower, and the level is lowered. Each time the operating time is getting shorter.

On the other hand, when the heating output exceeds 50%, the magnetron 3a and the rotary antenna 2, and the magnetron 3b and the turntable 7 are operated together (steps 2 and 4). This actual operation is as shown in FIG.
For example, there are levels from 6 to MAX, and at the MAX level, the magnetron 3a and the rotating antenna 2, and the magnetron 3b and the turntable 7 are continuously operated, and the magnetron 3a, the rotating antenna 2, and the magnetron 3b are connected to each other as the level decreases. The turntable 7 is operated alternately, and the operation time is short.

[0012]

According to the present invention, when the heating output is reduced, the heating is performed only by the radiation of the radiating portion in the upper part of the heating chamber, whereby the low output heating is always stirred by the radio wave stirring mechanism. It is efficiently performed by radio waves, and as a result, it is possible to enhance the low-output heating performance in a microwave oven having radio wave irradiation units at the upper and lower portions of the heating chamber.

[Brief description of drawings]

FIG. 1 is a simplified configuration diagram of a microwave oven of the present invention.

FIG. 2 is a circuit configuration diagram of the microwave oven of the present invention.

FIG. 3 is a flowchart for explaining the operation.

FIG. 4 is a diagram showing an operation sequence of the present invention.

FIG. 5 is a diagram showing an operation sequence of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating chamber 2 Rotating antenna (radiating part, stirring mechanism) 7 Turntable 10 Opening part (radiating part) 21 Control part (heating control means)

Claims (1)

[Claims] 1. A microwave oven in which a radio wave radiation section is provided in the upper and lower portions of the heating chamber, a radio wave agitation mechanism is provided in the upper portion of the heating chamber, and a turntable is provided in the lower portion of the heating chamber. In this case, the microwave oven is provided with heating control means for performing heating only by the radiation of the radiation part above the heating chamber.