JPS6321421A - Heating device - Google Patents

Abstract

PURPOSE:To allow a shape of a heated item to be identified and provide an automatic setting of a heating time by a method wherein a ultrasonic wave sensor and a weight sensor are provided, a heated item is rotated, height data of the heated item are continuously inputted to a control part to detect a size of the heated item. CONSTITUTION:An ultrasonic-wave sensor 6 is arranged on a ceiling of a heating chamber 7 and a heated item 9 is rotated by a rotary mounting table 8. Under this condition, as the rotary mounting table 8 within the heating chamber 7 is started to rotate, a relative positional relationship between the heated item 9 and the ultrasonic-wave sensor 6 is varied. Height data of the heated item are continuously inputted to a control part 5, the control part may detect a certain rotational section of the heated item in response to the data and then a size of the heated item can be estimated. Then, the control part may detect a weight of the heated item by applying a weight sensor 10 arranged below the rotary mounting table. With the foregoing arrangement, it is possible to provide an accurate acknowledgement of a shape of the heated item and perform an automatic heating of the heated item.

Description

[Detailed description of the invention] Industrial application field.

The present invention relates to a heating device that realizes automation of the heating device by recognizing the shape of an object to be heated.

The conventional automatic high-frequency heater described in Japanese Unexamined Patent Publication No. 50-152334 detects the thickness -gv of the object to be heated using a wave detector and automatically sets the heating time.

This is the size of the load on the object to be heated, equivalent to water vtg+
is detected by a detector placed in the auxiliary waveguide, and from this, the manually set initial temperature Ts', and the finished temperature Te, a heating time proportional to vx (Te - Ts') is calculated, and the heating time is automatically calculated. It controls the heating.

The magnitude V of the object to be heated as a load is realized by detecting a part of the heating radio waves.

Problems to be Solved by the Invention However, in such conventional automatic heating methods, the size of the object to be heated is estimated from the degree of matching between the magnetron and the load, and the size of the object to be heated is estimated by the impedance of the magnetron. It is detected whether the object is heavy or light, and from this the size of the object in terms of water can be determined, but the volume of the object to be heated is not actually detected.

However, the high frequency current detected by the wave detector varies significantly depending on the temperature of the magnetron, and the size of the object to be heated, V, in terms of water, is not stable. In other words, even if the object to be heated is the same size, the high-frequency current increases when it is cold, and as the magnetron is repeatedly used, the magnetron warms up, the high-frequency current decreases, and the size of the object to be heated is detected to be smaller. In view of this background, the present invention attempts to detect the actual volume of the object to be heated and automatically control the heating time based on this and weight data.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an ultrasonic sensor on the ceiling of the heating chamber, rotates the object to be heated on a rotating mounting table, and measures the distance to the object to be heated. is continuously input to the control unit, and a weight sensor is used to detect the size and weight of the object to be heated, and the heating time is automatically controlled from these.

Function In the heating device of the present invention, since the ultrasonic sensor is attached to the upper surface of the heating chamber, the distance to the object to be heated is continuously input to the control unit by rotation of the rotary mounting table, and the control unit receives this data. The rotational cross section of the object to be heated can be detected from this, and the size and volume of the object to be heated can be estimated from this.

Based on this and the weight data, the control unit can set the heating time or a factor that determines the heating time and control the power supply to the heating means.

EXAMPLE Hereinafter, a heating device according to an example of the present invention will be explained with reference to the drawings.

FIG. 2 is a perspective view of the main body of the heating device according to the present invention.

A door body 2 is pivotally supported on the front surface of the main body 1 so as to be freely openable and closable, and an operation panel 3 is provided. A keyboard 4 is arranged on this operation panel 3.

FIG. 1 is a block diagram showing the configuration of such a heating device. Operation commands input from the keyboard 4 on the operation panel 3 are decoded by the control section 5. Then, the control unit 5 uses the ultrasonic sensor 6 to measure the distance to the object to be heated.

Since the distance from the ultrasonic sensor to the rotating mounting table is constant,
If the object to be heated comes below the ultrasonic sensor, the reflection returns to the ultrasonic sensor quickly. The height of the object to be heated can be determined by the difference.

In other words, the height of the heated object is h=H-d　　h-Height of the heated object H-Distance to rotary mounting table d - detected distance (See Figure 1).

Now, when the rotary mounting table 8 in the heating chamber T starts rotating in this state, the relative positional relationship between the object to be heated 9 and the ultrasonic sensor 6 changes. Then, the height data of the object to be heated is input one after another to the control section, and the control section can detect a certain rotational cross section of the object to be heated from this data, and can estimate the size (volume) of the object to be heated from this data.

Next, the control unit controls the weight sensor 1 provided below the rotary mounting table.
o is used to detect the weight of the object to be heated.

As the weight sensor 10, a capacitance method or a strain gauge method for detecting the displacement amount of the rotary mounting table 8, a vibration method for measuring the natural frequency of the mounting table using a magnet and a coil, etc. can be adopted. The motor 11 is a drive source that rotates the rotary mounting table 8 .

The ultrasonic sensor inputs data to the control unit via the detection circuit 12, and the weight sensor inputs data to the control unit via the detection circuit 13.

FIG. 3 shows a narrow ultra-directional ultrasonic microphone as an example of an ultrasonic sensor. The ultrasonic sensor includes a piezoelectric element 14,
It consists of a conical resonator 15, a terminal 16, a beam shaping plate 17, a case 18, a lead wire 19, a coupling shaft 20, a terminal plate 21, and a sound absorbing sheet 22. (National Technical Report P, 504-514 Vol. 29
No. 3 JAN 1983) FIG. 4 shows the volume of a heated object detected using such an ultrasonic sensor. The horizontal axis represents the position (rotation angle) of the rotary mounting table, and the vertical axis represents the height of the object to be heated. Therefore, the continuous data of the height of the heated object detected at each position on the mounting table (the shaded area) represents the rotational cross section of the heated object, and the ultrasonic sensor should be installed at the appropriate position. If selected, the shape of the entire object to be heated can be estimated.

1=80 m indicates the distance of the ultrasonic sensor from the center of the heating chamber, and in one experiment, the shape of the object to be heated could be determined best at this position. In any case, better results can be obtained by placing the sensor slightly off the center of the ceiling of the heating chamber. This is because if the sensor is placed in the center, the relative positional relationship with the object to be heated will not change much.In an extreme example, if the object to be heated is placed in the center of the mounting table, the sensor will be placed at a point in the center of the object. This is because only the height of the object can be detected and the overall shape cannot be determined.

Note that the optimum value of one value naturally changes depending on the size of the heating chamber and the selection of the ultrasonic sensor.

Figure 4 shows the data for spinach and potatoes, but as is clear from the figure, there is a considerable difference between the two if their weights are the same. In other words, if the weight and volume can be detected, in the case of vegetables, for example, it is possible to identify whether they are leafy vegetables (spring grass) or root vegetables (potatoes). Based on this determination, the heating means 2 is heated via the driver 26.
It is possible to control the power supply to 6 and automate heating.

Now, FIG. 5 is a block diagram showing an example of the configuration of a detection circuit of an ultrasonic sensor.

The control unit 5 is composed of a microcomputer or the like, and performs timing control so that one ultrasonic sensor transmits an ultrasonic wave of several tens of KHz, and when receiving the ultrasonic wave, it is switched to a receiver and operates.

23 is a transmitting circuit, and 24 is a receiving circuit. Comparison circuit 25
compares the reference voltage and the received signal, latches the received signal exceeding this reference voltage, and inputs it to the control section 6. The control unit 5 counts the time from transmitting the ultrasonic waves to receiving them, calculates the distance to the object to be heated from the propagation velocity of the ultrasonic waves, and calculates the height of the object from this.

With the above configuration, the shape of the object to be heated can be accurately recognized, and the object to be heated can be automatically heated.

Effects of the Invention As described above, the heating device of the present invention is equipped with an ultrasonic sensor and a weight sensor, rotates the object to be heated using a rotary mounting table, and continuously transmits height data of the object to the control unit. By inputting this information, the size of the object to be heated can be detected, the shape of the object to be heated can be recognized with good reproducibility, and the heating time of the object to be heated can be automatically set.

Furthermore, since an ultrasonic sensor is used as a shape recognition sensor, it is much cheaper and more resistant to dirt than optical sensors such as cameras and CODs that are commonly used. In heating devices such as microwave ovens, the heating chamber gets quite dirty with oil, and the sensors installed in these devices usually require measures such as burning off the dirt with a heater, but if it is a drip-proof ultrasonic sensor, the element It is impossible for the material itself to change physically or chemically over time due to dirt, so there is no need for such consideration.

As described above, according to the present invention, detection can be performed with good reproducibility even after repeated use, and stable operation can be expected over a long period of time.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of a heating device according to an embodiment of the present invention, Fig. 2 is a perspective view of the main body, Fig. 3 is a sectional view of a narrow directional ultrasonic sensor, and Fig. 4 is an ultrasonic sensor. FIG. 6 is a circuit block diagram showing a configuration example of a detection circuit of an ultrasonic sensor. 5...Control unit, 6...Ultrasonic sensor,
7... Heating chamber, 8... Rotating mounting table, 9
... Heated object, 1° ... Weight sensor,
26... Heating means. Name of agent: Attorney Toshio Nakao and 1 other person 2nd
Fig. 3 Fig. 4

Claims (1)

[Claims] a heating chamber in which an object to be heated is placed; a heating means coupled to the heating chamber; a control section that controls power supply to the heating means; an ultrasonic sensor that detects the size of the object to be heated;
The apparatus comprises a weight sensor that detects the weight of the object to be heated, and a rotating mounting table that rotates the object to be heated, the ultrasonic sensor is provided on the upper surface of the heating chamber, and the control section uses the ultrasonic sensor to The height of the heated object is estimated by detecting the distance to the heated object, and the size of the heated object is recognized from distance data that is continuously input by rotation of the rotary mounting table. The heating device is further configured to set a heating time or a factor for determining the heating time based on the weight of the object to be heated detected by the weight sensor, and to control power supply to the heating means.