JPH0456093A - High frequency heating device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high-frequency heating device that uniformly heats the objects by placing the objects on 11 rotating objects in a heating chamber.

Conventional technology In recent years, high-frequency heating devices have been developed in which the object to be heated is placed on a rotating object mounting table within a heating chamber, and the object is heated uniformly and appropriately depending on the weight of the object. things are becoming mainstream.

Conventionally, this type of high-frequency heating device places a microwave detection sensor inside the heating chamber, and uses the characteristic that the reflected microwave power that is not absorbed by the detected object to be heated to be heated to be inversely proportional to the weight of the object to be heated. Detects the weight of heated objects in the room,
The heating was done according to the weight. Further, in order to uniformly heat the object, a rotating object mounting table (hereinafter referred to as a turntable) on which the object is placed has been used.

In order to drive this turntable, conventionally, as shown in FIG.
The object to be heated 43 is placed on a turntable 39 and is supported by a support ring 42 consisting of a bracket 41 that fixes the rotating shaft of the roller 40 . A projection 45 is provided at the center of the turntable 39 to receive the rotational force of the turntable 39 via a pulley shaft 44. Therefore, the object to be heated 43
The weight of the turntable 39 is supported by the roller 40 of the support ring 42, and the rotation is carried out by the turntable motor 46. As shown in FIG. 13, a turntable 39 on which an object to be heated 43 is placed is rotatably moved on rollers 40 connected by brackets 41.

Problems to be Solved by the Invention In such a conventional high-frequency heating device, the moving distance of the roller 40 is only half of the moving distance of the turntable 39. This situation is shown in FIG. 14(a) et al. In FIG. 14(a), the turntable 39 and roller 40
are in contact at point b, and the roller 40 is in contact with the ground at point a. When the turntable 39 moves Lab in the direction f using point a as a fulcrum in FIG.
LacL does not move. Therefore turntable 3
15(a) showing the relationship between the turntable 9 and the roller 40, when the turntable 39 makes one rotation in the counterclockwise direction from the point S, the roller 40a rotates around the turntable 39 as shown in FIG. 15(b). Although the starting point S has returned to its original position, the roller 40a has rotated only half way. At this time, the output of the microwave detection sensor (hereinafter referred to as detection sensor) that detects the reflected microwave power in the heating chamber fluctuates due to the rotation period t1 of the turntable 39, as well as the fluctuation due to the rotation period t1 of the turntable 39, as shown in FIG. It also changes every rotation period t2 of the support ring 42 made up of the bracket 41. Comparing the average value Vml of the first rotation of the turntable 39 to Vm4 of the fourth rotation after heating by microwaves is started, the detection signal changes depending on the position of the roller 40 in accordance with the rotation period t2 of the support ring 420. Therefore, in order to set the remaining heating time using a timer based on the output signal obtained by detecting the output of the detection sensor and amplifying the DC current, the detection signal must be becomes inaccurate;
There was a problem that it took time to obtain an accurate signal.

The present invention solves the above problems, and aims to provide a high-frequency heating device that suppresses and stabilizes the fluctuation of the microwave detection signal that fluctuates due to the rotation of the turntable, and is capable of accurate calculation processing. In order to achieve the above object, the present invention includes a detection sensor that detects the amount of reflection of high frequency energy from an object to be heated in a heating chamber, and a turntable on which the object to be heated is placed and rotates. The solution to the problem is that the turntable is supported by an even number of rollers arranged at equal angles to the rotation axis.

Operation The present invention uses the above-mentioned problem solving means to suppress the output signal of the detection sensor to fluctuations only in the rotation period of the turntable. Therefore, by simply smoothing the signal and inputting it to a microcomputer, etc., a stable output signal from the detection sensor can be obtained, and subsequent signal processing can be simplified.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 6.

As shown in the figure, microwaves excited by a magnetron 1 are guided into a heating chamber 3 by a waveguide 2 and absorbed by an object to be heated 4. After cooling the magnetron 1, the air generated by the fan 5 enters the heating chamber 3 through a number of small holes 6 provided on the side surface of the heating chamber 3, and absorbs the heat generated as a result of heating the object 4. The gas is transported, enters the exhaust guide 8 through a large number of small holes 7 in the opposing wall of the heating chamber 3, and is exhausted to the outside of the outer shell 9. A detection sensor 1 is installed on the ceiling of the heating chamber 3.
0 is installed perpendicularly to hole 11. The object to be heated 4 is placed on a turntable 12 for uniform heating, and the turntable 12 is rotated by a turntable motor 13. The turntable 12 is supported by a support ring 16 consisting of an even number of rollers 14 arranged at equal angles to the rotation axis and a bracket 15 fixing the rotation axis of the rollers 14, and supported by a projection 17 provided at the center. It is rotatable by receiving the rotational force of the pulley shaft 18. On the other hand, the intensity of the microwave measured by the detection sensor IO is amplified by an amplifier circuit 19 and then input to a microcomputer (hereinafter referred to as microcomputer) 20.

The detection sensor 10 is mounted on a printed circuit board 21 as shown in FIG.
Copper foil pattern 22 etched on top and chip component 2
It is composed of three groups, and an antenna 24 formed by etching is installed opposite a hole 11 made in the heating chamber 3 through a plate 25. As shown in FIG. 5, the signal detected by the antenna 24 is detected by the detection diode 26, and the detected high-frequency voltage is passed through the filter section 27 only for the low frequency component, and is converted into DC by the smoothing section 28, and then detected. This becomes the output of the sensor 10.

After the output of the detection sensor 10 passes through the amplifier circuit 19, as shown in FIG. 31, the weight W is calculated and V
Va-Vb is calculated by the a-Vb calculation unit 32, and ■a-■
The heating time T is stored in the b memory 33, and the heating time T is calculated by the T calculation unit 34. The heating time T is set in the timer 35, and the subtraction processing section 36 starts subtraction. The content being subtracted is also displayed on the external display unit 37. During subtraction, the switch 3rd is turned ON.

When the subtraction process ends, cooking ends.

To explain the operation in the above configuration, the relationship between the output of the detection sensor 10 and the weight of the object to be heated 4 is as shown in FIG. The weight W can be estimated from the characteristic of being small. In addition, FIG. 8 shows the temporal change in the output of the detection sensor 10. The voltage level Va at the start of heating and the voltage level Vb after 1 minute are measured, and the difference between them indicates the progress of heating, for example, defrosting. can be known. Furthermore, the difference in heating time depending on the initial temperature of the object to be heated 4 is known experimentally, and a 10 degree difference in initial temperature results in a difference of approximately 20% in time.

Therefore, the optimum decompression time can be calculated from Va-Vb and W. Therefore, unless both the absolute value and the elapsed time of the output signal of the detection sensor 10 are stable, it will not be possible to accurately calculate the optimal decompression time.

Therefore, by setting the number of rollers 14 of the support ring 16 to an even number such as 4 as shown in 21g(a), when the turntable 12 makes one rotation from the starting point S, the roller 14a rotates 180 degrees and the roller 14b It comes to the position of
Since they are symmetrical, the rollers 14a and 14b are simply exchanged as shown in FIG. 2, etc., and the time course of the output signal of the detection sensor 10 becomes as shown in FIG. NMVml is now completely unaffected by the roller I4 of the support ring 16.

FIG. 10 is a flowchart of the processing process of the microcomputer 2o that executes the above-mentioned detection process. After the start of cooking, the output of the detection sensor 10 is measured. As shown in Fig. 11, this is calculated by integrating the output of the detection sensor 10 for 10 seconds corresponding to one rotation of the turntable and dividing this by the integration time of 10 seconds.
get a. The weight W is calculated from this integral output Va, and a similar integration is performed one minute later to obtain an integral output vb. W and V
Calculate the remaining heating time T from a-Vb. After T has elapsed, cooking ends.

As described above, according to the high frequency heating device of the embodiment of the present invention,
The weight W of the object to be heated 4 is calculated by averaging the output of the detection sensor 10 for each rotation of the turntable 12, and the average value for each rotation of the turntable 12 is influenced by the roller 14 of the support ring 16. Therefore, the weight W of the object to be heated 14 can be accurately calculated, and the remaining heating time T can be calculated.

Effects of the Invention As is clear from the above embodiments, according to the present invention, there is provided a microwave detection sensor that detects the amount of reflection of high-frequency energy from an object to be heated in a heating chamber, and a sensor that rotates with the object to be heated placed thereon. Since the turntable is supported by an even number of rollers arranged at equal angles to the rotation axis, it is stabilized by suppressing fluctuations in the output signal of the detection sensor that fluctuates due to the rotation of the turntable. As a result of accurate and precise processing, it is possible to determine a stable and optimal heating time, and automation of heating can be realized.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of a high-frequency heating device according to an embodiment of the present invention, FIGS.
The figure is a partially cutaway front view of the high-frequency heating device, Figure 4 is an exploded perspective view of the detection sensor of the high-frequency heating device, Figure 5 is a circuit diagram of the detection sensor, and Figure 6 is the same high-frequency heating device. A data flow diagram inside the microcomputer, Figure 7 is a characteristic diagram of the weight of the heated object of the same high-frequency heating device and the output signal of the detection sensor,
Fig. 8 is a time change characteristic diagram of the output signal of the detection sensor of the same high frequency heating device at different initial temperatures of the heated object, and Fig. 9 is a time change characteristic diagram of the output signal of the detection sensor of the same high frequency heating device. 1θ diagram is a flowchart showing the processing contents of the microcomputer of the high-frequency heating device, FIG. 11 is a subroutine flowchart of the same flowchart, FIG. 12 is an exploded perspective view of the turntable drive device of the conventional high-frequency heating device, and FIG. 13 is an exploded perspective view of the turntable drive device of the conventional high-frequency heating device. Same side view, Fig. 14(a), (
b) is an explanatory diagram showing the difference in the travel distance of the turntable and the support ring as the turntable rotates;
slli4(a) and (b) are plan views showing the operating states of the turntable, respectively, and FIG. 16 is a time variation characteristic diagram of the output signal of the detection sensor of the high-frequency heating device. 1... Mag-Kayatron, 3... Heating chamber,
4... Heated object, lO... Detection sensor (microwave detection sensor), 12... Turntable (heated object mounting table), 14...・Name of Lawlor's agent: Patent attorney Shigetaka Awano Haka1 person! -Makotron Figure 2 (α) (b) Figure 3 Figure 3 [A] 411 hours (minutes) Figure 0 Whistle; 3 rt. Figure (cL) Combined ■ Figure 4/ (b) Figure 2 Figure 15 (IL) Old Figure 6 rl)) #Mountain

Claims (1)

[Claims] a heating chamber in which an object to be heated is placed, a magnetron that supplies high frequency energy to the object to be heated in the heating chamber, a microwave detection sensor that detects the amount of reflection of high frequency energy from the object to be heated in the heating chamber; A high frequency device comprising: a heated object mounting table that rotates with the heated object mounted thereon; the heated object mounting table is supported by an even number of rollers arranged at equal angles to a rotation axis; heating device.