JPS6122592A - Heater with automatic weight measuring 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] Industrial Application Field The present invention measures the weight of the object to be heated using the vibration frequency, and automatically sets the heating time, output, heating pattern, etc. according to the weight. This invention relates to an automatic weight measuring device and a heating device.

Conventional structure and problems Conventionally, in general heating devices, the weight of the object to be heated is measured before cooking using a scale, etc., and the heating time and heating output are determined based on the weight using a rotary timer or output setting key. This requires a cumbersome operation in which the user must set a new password, and there is a problem in simplifying the operation procedure.

Purpose of the Invention The present invention solves the above-mentioned conventional problems.The present invention automatically measures the weight of the object to be heated from the vibration frequency of the object on the table and automatically heats it based on the weight data. The present invention provides an automatic weight measurement device and heat addition device.

Structure of the Invention In order to achieve this object, the automatic weight measuring device heat addition device of the present invention includes a vibration generator that generates vibrations on a mounting table, a frequency detection device that detects the frequency of the object to be heated on the mounting table. , a control circuit that calculates the air volume of the object to be heated from the frequency detected by the frequency detection device, and controls the heating output, heating pattern, and heating time of the heating means based on the calculated weight, The mounting table is provided with a spring whose frequency changes according to 1Affl of the object to be heated.

According to the configuration described above, the object to be heated placed on the table is forced to vibrate by the vibration generator, the vibration frequency is detected by the vibration frequency detector, and the object to be heated is vibrated based on the detected frequency. The control circuit operates and automatic cooking can be performed.

Description of examples An embodiment of the present invention will be described based on the drawings.

FIG. 1 shows an external perspective view of a microwave oven, which is a high-frequency heating device.

1 is a display section that displays the weight of the object to be heated, heating time, heating means, etc.; 2 is a key on which various keys are arranged for selecting the heating time, heating means, heating output, cooking type, and starting cooking. The human power section 3 is a heating chamber for storing and cooking objects to be heated. Reference numeral 4 represents a door that can be opened and closed at the front of the heating chamber 3 for taking in and out the heated object, and 5 represents the body of the microwave oven.

FIG. 2 shows a sectional view of essential parts of the microwave oven taken along line AA' in FIG. Reference numeral 6 denotes food as the object to be heated; 7 is a magnetron that is a high frequency oscillator provided at the rear rear side of the heating chamber 3 to heat the object 6; and 8 is the food 6.
It is a rotatable table on which food 6 is placed, and generates magnetic vibrations according to the weight of the food 6. The magnetic vibrations are transmitted to the outside of the heating chamber 3 as food weight information. Reference numeral 19 denotes a magnetic vibration detection unit using a coil for detecting magnetic vibration, which is food weight information, and the magnetic attraction generated by passing a current through the coil of the magnetic vibration detection unit 19 for a certain period of time causes the placing table 8 to
The magnetic vibration detection section 19 also has a function as a vibration generator in order to apply initial vibration to the magnetic vibration detection section 19 . 20 is a motor for rotating the table 8.

FIG. 3 shows a cross-sectional view of the vicinity of the mounting table 8, and FIG. 4 shows an exploded perspective view of the vicinity of the mounting table 8, with X marks indicating spot welds. Reference numeral 9 denotes a wheel that smoothly rotates a rotatable table 8 that heats the food 6 evenly, and 10 denotes a rotating shaft of the wheel 9 and an arrangement ring that arranges the wheel 9 in a circular manner. Reference numeral 11 denotes a leaf spring that generates a frequency corresponding to the weight of the food, and is provided at the lower part of the upper plate of the table 8.

Reference numeral 12 denotes a spacer for fixing the plate springs j1 in parallel and at a constant distance. Reference numeral 13 is a spring fixing plate that fixes the leaf spring 11 and the spacer and is caulked. Reference numeral 14 denotes a rotatable support table that supports one end of the plate spring 11 on the wheel 9 and is rotatable. Reference numeral 15 denotes a plate spring mounting plate for fixing the plate spring 11 and attaching the end of the plate spring 11 to the mounting table 8 and the support rotating table 14. In addition, in order to avoid applying partial force to the rotation support base 14 and the mounting base 8 due to the material 15 when attaching the leaf spring, the reinforcing material 16 is attached to the rotation support base 14 and the mounting base 8 by the material 15. It is installed between.

A magnet 17 is provided at the center of the back surface of the table 8, and like the leaf spring 11, it vibrates at a frequency corresponding to the weight of the food 6. Further, this magnet 17 is protected by a magnet cover 18 made of a material that blocks high frequencies and allows magnetic fields to pass through. Reference numeral 19 denotes a magnetic vibration detection section that detects changes in the magnetic field from the magnet 17, and uses a coil. As the magnet 17 vibrates, the distance between the magnetic vibration detection section 19 and the magnet 17 changes, and the magnetic field strength in the magnetic vibration detection section 19 changes correspondingly. Due to the change in the magnetic field strength, an induced electromotive force having a frequency equal to the frequency of the magnet 17 is generated in the coil of the magnetic vibration detection section, and is scattered outside the heating chamber as weight information. The magnetic vibration detection section 19 also functions as a vibration generation section that applies initial vibration to the food 6.

20 is a motor for rotating the support rotary table 14, and the rotational force of the motor 20 is indirectly transmitted through the transmission shaft 21. Reference numeral 22 designates a plate for mounting a coil that is attached to the back side of the bottom plate of the #8 chamber 3 and supports the magnetic vibration detection unit 19, and reference numeral 23 designates a plate for mounting a motor for fixing the motor 20.

The operating principle when the magnetic vibration detection section 19 is used for detecting magnetic vibration will be explained based on FIG.

In FIG. 5(a), when the distance between the magnet 17 and the coil I/V 19a of the magnetic vibration detection unit 19 is vibrating in the direction of narrowing, the magnetic flux passing through the coil I/V 19a increases and attempts to cancel it. An induced current I flows through the coil/L'19a in a direction that generates magnetic flux shown by the dotted line.

When the magnet 17 and the coil 19a vibrate in a direction in which the distance between them widens in FIG. 5(b), an induced current I flows through the coil 19a in the opposite direction to that in FIG. 5(a).

The induced electromotive force V that generates this induced current I is expressed as dΦ v--n-, where the magnetic flux passing through the coil is Φ and the number of turns of the coil is n. If so, it can be seen that the induced electromotive force V also has the same angular frequency W. Therefore carp/I/19a
By detecting the frequency of the induced electromotive force, it is possible to detect the frequency of the magnet 17, that is, the frequency of the spring corresponding to the weight of the food.

The operating principle when the magnetic vibration detecting section 19 is used for generating vibrations will be explained based on FIG. 6. Figure 6 (
In a) and (b), if a current is passed through the coil 19a of the magnetic vibration detection unit 19 for a certain period of time, Nm and S poles are generated at both ends of the coil 19a, attracting or repelling the magnet 17, and giving initial vibration to the spring. After the vibration occurs, the carp/L'19a is 9λ. FIG. 7(b) shows a sectional view of the vicinity of the leaf spring 11 in FIG. 3. In FIG. 7(b),
The weight of the food 6 is applied to the table 8, and the weight is applied to one end of the plate spring 11 by the reinforcing member 16 attached to the table 8 and the plate spring attachment member 15. Further, since the other end of the leaf spring 11 is fixed to the support rotating table 14, the leaf spring 11 bends and vibrates. The magnet 17 vibrates, and the magnetic vibration can be detected by a magnetic vibration detection section 19 (not shown). Further, a configuration in which the leaf springs 11 are fixed in parallel is called a donkey pal mechanism, and is common in the field of scales. With this donkey pal mechanism, even if the food 6 is placed at any position on the table 8, the change in weight applied to the leaf spring 11 can be reduced depending on the position where the food 6 is placed.

FIG. 8(a) is a diagram showing the relationship between the distance between the magnet 17 and the magnetic vibration detection section 19 and the magnetic field strength H in the coil 19a. ■) in the same figure shows that when the magnet 17 performs simple harmonic motion, the magnet 17
This is just a diagram showing how the distance between the magnetic vibration detecting section 19 and the magnetic vibration detecting section 19 changes over time.

Figure (C) shows the change over time in the magnetic field strength H in the magnetic vibration detection unit 19 due to the vibration of the magnet 17 from Figures (,) and (b). The same figure (d) shows the magnet 17.
This figure shows the change over time in the induced electromotive force V generated in the coil 19a of the magnetic vibration detection unit 19 due to simple harmonic motion.

Therefore, since the frequency of the induced electromotive force generated in the magnetic vibration detection section 19 and the frequency of the vibration of the magnet 17 are the same, it is possible to detect the frequency of the magnet 17 by detecting the frequency of the induced electromotive force. It is possible.

Next, an example of a waveform conversion circuit for extracting the induced electromotive force of the magnetic vibration detection section 19 as a pulse signal will be described. In FIG. 9, the induced electromotive force in the coil 19a of the magnetic vibration detection section 19 is applied at point A. At point B, the voltage at point A is amplified by a negative feedback operational amplifier.

By inputting the amplified voltage at point B to the comparator, the coil 19 is connected to point 0, which is the output section of the comparator.
A square wave having the same frequency as the induced electromotive force of a is output.

FIG. 10 shows the relationship between the vibration of the magnet 17 and the output waveform at point C in FIG. In FIG. 10 (,), the frequency becomes high when the weight of the food is small. Conversely, in FIG. 10(b), when the weight of the food is large, the frequency becomes low.

As can be seen from the relationship shown in FIG. 10, the weight of the food can be detected from the frequency of the output waveform at the 0 point in FIG. 9.

FIG. 11 is an example of a control circuit for a microwave oven according to the present invention. A microcomputer 24 performs information processing such as storage, judgment, calculation, and data input/output. Reference numeral 25 denotes an oscillation circuit, which generates a fundamental frequency for measuring the vibration frequency of the magnet 17.

26 is a fan motor for cooling the magnetron 7;
Reference numerals 27 and 28 are a relay for controlling the output of the magnetron 7 and a relay for the drive circuit of the magnetron 7, respectively. 29 and 30 are relays for switching the coil 19a to either magnetic vibration detection or vibration generation.

31 is a DC voltage circuit for supplying DC voltage to the coil 19a when the coil/L/19a is selected as the vibration generator by operating the relay 29.30. Supply voltage.

The weight measurement operation will be explained based on FIG. 12.

12(a) shows a square wave obtained by converting the vibration of the magnet 17 into a pulse signal by the waveform conversion circuit shown in FIG. 9, and FIG. 12(b) shows the output waveform of the oscillation circuit 25. Figure 12 (C
) (This is a flowchart showing the flow of the weight measurement method. In other words, a coil) V19aK DC current is applied, and the generated magnetic field attracts or repels the magnet 17 to generate vibration, and the same coil 19a is used for magnetic vibration detection. The vibration is detected as an induced electromotive force, and the waveform is shaped by the waveform conversion circuit shown in FIG. 9 to obtain the pulse shown in FIG. 12 (,). The frequency of the magnet 17 can be detected by counting the pulses from the oscillation circuit 25 between the falling P/P point and the next P/N falling point in FIG. 12(,). .

An example of operation of a microwave oven according to an embodiment of the present invention will be explained with reference to FIG.

FIG. 13 is a front view of the display section 1 and key operation section 2 of a microwave oven according to an embodiment of the present invention. The key unit 2 has a cooking menu selection key, which determines the heating time, output, and pattern depending on the selected menu and the measured weight of the food. The operation will now be explained using an example of thawing frozen food. "Unzip" key 3 of key human power section 2
When 2 is pressed, "°0 minutes 00 seconds" is displayed on the display section 1 as an initial value. Next, the frozen food is placed on the table 8 in the heating chamber 3, the door 4 is closed, and the "cooking start" key 33 is pressed to forcefully vibrate the food, detect the vibration frequency of the food, and detect the detected vibration. The microcomputer 24 calculates the weight based on the number, displays the heating time T corresponding to the calculated weight on the display section 1, and starts heating. From then on, the remaining nine hours are displayed as being subtracted every second as time passes.

Furthermore, the heating power P, heating time T, and heating pattern for defrosting the food in this case are as shown in FIG.

The weight, heating time, and heating pattern shown in FIG.
3 is determined and decompression proceeds, and when a predetermined time has elapsed, high frequency oscillation stops and decompression is completed. Furthermore, Fig. 14(a)
shows a heating pattern in which heating is performed for T1 seconds at an output of 600 W, stopped for the next 12 seconds, and heated at an output of 200 W for the next 13 seconds. Furthermore, Fig. 14 Φ) is T1 and T2, respectively.
, T3 time is determined from the food weight wg, T1=KIXW, T2=2XW, T3=3XW.
K1, K2, and K3 are constants determined in advance.

As described above, simply by placing food in the heating chamber 3, vibrations are automatically generated, the weight is measured, and the heating time and heating pattern are controlled, so that cooking can be performed with simple operations.

In addition, since the coil 19a, which is the food vibration detection section, is provided outside the heating chamber 3, it is not affected by the high frequency waves inside the heating chamber 3, and the detection section has excellent durability. Furthermore, since the coil 19a is used both for detecting magnetic vibrations and for generating vibrations, it is very cost effective and has great effects.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) The weight of the heated object can be measured simply by placing it in the heating chamber, eliminating the need for weighing before cooking.

(2) Since the weight of the object to be heated is measured by the frequency of the spring, the cause of measurement error is the elastic constant of the spring, as well as variations in the elastic constant caused by uneven assembly of the donkey pal mechanism, and the magnetic field. It is not affected by the strength of the signal or variations in the detection circuit.

(3) Since it has a vibration generator, it is possible to apply vibration to the spring at any time and with any strength, so there will be no malfunction due to external vibrations such as door opening/closing, and therefore measurement errors will not occur.

(4) Since the information necessary for weight measurement is the vibration frequency of the spring, the weight can be detected simply by converting it into pulses with the same period, and converting the analog waveform into a digital waveform A-
The detection circuit can be simplified without requiring a D conversion function, which is advantageous in terms of cost.

[Brief explanation of drawings]

FIG. 1 is an external perspective view of a microwave oven according to an embodiment of the present invention;
Fig. 2 is a sectional view of the main parts of the microwave oven taken along line A-A' in Fig. 1, Fig. 3 is a sectional view of the vicinity of the microwave oven stand, and Fig. 4 is an exploded perspective view of the vicinity of the microwave oven stand. Figure 6 is a diagram explaining the operating principle in vibration detection, Figure 6 is a diagram explaining the operating principle in vibration generation, Figure 7 (a) is a diagram with a weight suspended on a spring, and Figure 7 (b) is a diagram explaining the operating principle in vibration generation. 8 is a diagram showing the relationship between various quantities in the vibration detection section, FIG. 9 is a waveform conversion circuit diagram of an embodiment of the present invention, FIG. 10 is a characteristic diagram showing the relationship between weight and frequency, and FIG. The figure is a circuit diagram of the control section of the microwave oven, Figure 12 (, ) is an output waveform diagram of the waveform conversion circuit, Figure 12 (crest) is an output waveform diagram of the oscillation circuit, and Figure 12 (c) is an output waveform diagram of the oscillation circuit.
) is a flowchart showing the flow of weight measurement, FIG. 13 is a front view of the microwave key manual section and display section, and FIG. 14 is a characteristic diagram showing conversion of the heating sequence for defrosting. 3... Heating chamber, 7... Magnetron (
high frequency oscillator), 8... place stand, 11...
- Plate spring, 19... Magnetic vibration detection section (vibration detection device and vibration generator), 24... Microcomputer (control section). Name of agent: Patent attorney Toshio Nakao p! Figure 1 Figure 2 Figure 4 Figure 7 rα) Figure 8 aI Distance L (bl Figure 9 Figure 1θ Figure 12 Figure 13

Claims (4)

[Claims] (1) A heating chamber for storing an object to be heated, a heating means for heating the object to be heated, and an elasticity for placing the object to be heated and generating a frequency corresponding to the weight of the object to be heated. a vibration generator that actively generates vibrations on the mounting base; a frequency detection device that detects the frequency of the object to be heated on the mounting base; and a control circuit for controlling the means. (2) The automatic weight measuring device additional heat device according to claim 1, wherein the vibration generator is configured to use a solenoid. (3) The automatic apparatus according to claim 1, wherein the vibration frequency detection device uses a solenoid and is configured to transmit the vibration of the object to be heated on the stand as an induced electromotive force of the solenoid generated by magnetism to the outside of the heating chamber. Weight measuring device Addition heat device. (4) The automatic weight measuring device additional heat device according to claim 2, wherein the vibration generating device and the vibration frequency detecting device share a solenoid.