JPH0211822B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention measures the weight of the object to be heated and automatically controls the heating time, heating temperature, heating output, heating pattern, etc. according to the weight. This invention relates to a cooking device that enables cooking.

Conventional configuration and its problems Conventionally, in conventional cooking devices, the weight of the food to be heated is measured using a scale, etc., and the heating time and heating output are set based on the weight using a rotary timer or output setting key. etc. Therefore, cumbersome operations such as measuring, heating time, and heating output settings are required before starting cooking, and improvements in usability have been desired.

Therefore, as a measure to improve these, a configuration that automatically measures the weight of food and controls heating may be considered.
In this weight measurement method, as a concrete proposal,
There is a method in which a food table is supported by an elastic body and the amount of displacement of the elastic body that changes depending on the weight is measured. Alternatively, there is also a method of measuring the frequency of the elastic body in the same configuration as above.

The former method of measuring the amount of displacement of an elastic body tends to increase the vertical dimension when trying to obtain a certain range of food weight measurement, and if this displacement dimension is reduced, delicate measurement accuracy cannot be obtained. It has the following disadvantages.

Next, in the method of measuring the frequency of the elastic body, it is possible to configure the measuring section compactly, but it is susceptible to the effects of other external vibrations and the vibration of the main body itself, so the accuracy of weight measurement is poor. It has the disadvantage of being difficult to obtain.

Purpose of the Invention The present invention solves the above-mentioned conventional problems, and by realizing a compact weight measuring means that automatically weighs food accurately, automatically adjusts heating output, heating time, heating style, etc. The purpose is to improve the ease of use and improve the quality of cooking through control.

Structure of the Invention In order to achieve the above object, the cooking device with a weight detection function of the present invention supports a food table with an elastic body, and measures the weight by measuring the vibration frequency of this elastic body, The vibration frequency range of the elastic body in the measurement weight range is set so as to avoid the natural vibration frequency of the chassis, that is, the main body supporting and fixing the elastic body. With this configuration, there is no misjudgment in weight measurement due to external forces such as door opening/closing or external impact, improving measurement accuracy, and the weight measurement configuration using vibration frequency is compared to the method that originally measures displacement. Due to its compact configuration, it is possible to create an accurate weight measurement device that saves space, and has the effect of automatically determining the correct heating time and ensuring stable heating without having to set the heating time each time. .

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a partial sectional view of a cooking appliance with a weight detection function according to the present invention. In FIG. 1, a door 2 is provided at the front of a heating chamber 1 so as to be openable and closable. Radio waves oscillated from a magnetron (not shown) are irradiated into the heating chamber 1 to heat the object 3 at high frequency. The object to be heated 3 is placed on the rotating plate 4, and the rotating plate 4
is placed on the rotary mounting table 5. The rotary mounting table 5 is directly fitted onto the shaft of a motor 7 that passes through an opening 6 provided at the bottom of the heating chamber 1, and is driven to rotate by the motor 7. Motor 7 is block A
The block A8 is connected to the block B10 by a plurality of leaf springs 9, and the block B10 is fixed to the bottom 11 of the main body via a support member 12. Block A8, block B10, and leaf spring 9 constitute a roberval mechanism, so motor 7 fixed to block A8
moves vertically and elastically. A magnet 12 is provided on the block A8, and a detection coil 13 is provided on the bottom portion 11 of the main body in opposition to the magnet 12. Due to the action of the Roberval mechanism, block A8 is
The magnet 12 also moves, and this movement of the magnet generates a current in the detection coil. 14 is block A8 of the Roberval mechanism.
This is a pressure lever for pressurizing the door 2, and is configured to generate vibrations of the Roberval mechanism in conjunction with the opening/closing operation of the door 2.

The operation of the above configuration will be explained below.
The weight of the object to be heated is applied to the motor via the rotary mounting table, and since the motor is supported by an elastic body, it shifts downward in accordance with the weight. A detector detects this amount of displacement and the vertical vibration frequency of the motor section that occurs during the displacement, and the overall weight is determined from the detected amount. By measuring the weight of the rotating plate, rotating mounting table, and motor in advance, the weight of only the object to be heated can be detected from the overall weight.

By controlling the oscillation of the magnetron via the control unit based on this output, the object to be heated can be heated for an optimum heating time depending on the weight of the object. The detection coil 13 detects the amount of displacement and frequency of the magnet 12. The frequency of an object's vibrations is determined by the strength of the elastic body that supports it and the weight of the object, so by measuring its frequency, you can find out its weight.

Next, the vibration frequency, which is the key point of the present invention, will be explained. FIG. 2 is a diagram schematically showing the vibration system of the embodiment. In the figure, _M1 is block A.
This is the total mass of the parts that are integrally constructed with 8 and is supported by the leaf spring 9. M ₂ represents the total mass applied to the main body bottom plate 11, and since the main body bottom plate and the legs 15 that support the main body also have elasticity, the spring B
16. This spring B16 has a large adhesive or frictional resistance, and this spring B16 has a large adhesive or frictional resistance.
Shown as By opening and closing door 2,
The force f ₁ is applied to M ₁ and M ₁ starts to vibrate freely.
However, if the natural frequency determined from the elastic constant of spring B16 and M ₂ is close to the frequency determined from the above M ₁ and the elastic constant K ₁ of leaf spring 9, the kinetic energy of M ₁ is transmitted as a motion of M ₂ , and due to the resistance of CB, the vibration is
It also quickly decays. Figure 3 is a graph showing the relationship between actual measured values and true values for the phenomenon described above, and shows the measurement error when the frequency of _M2 matches the frequency of _M1 when it is around 300g. It represents.

In the present invention, after clearly grasping such problems, the elastic constant of the leaf spring 9 and the elastic constant of the block A8 are designed to greatly avoid the frequency in the measurement weight range of the object to be heated compared to the natural frequency of the main body. The mass of each part is set. As a result, the vibration of the Roberval mechanism can be maintained as a stable signal for a long time as shown in FIG. 4, so that extremely accurate weight measurement can be performed. In addition, strong impact force on the main body
Even when f ₂ is active, the natural frequencies are significantly different from each other, so it is possible to eliminate the inconvenience of canceling the free vibration of M ₁ due to overlapping of opposite phases.

In addition, as a method of exhibiting the effects of the present invention, it is also possible to deal with this by setting the mass and elastic constant of the main body to appropriate values. Specifically, there are ways to reinforce the bottom plate of the main body or change the thickness of the plate to make it heavier.

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

(1) Since the vibration damping due to the weight of the heated object is small, the vibration frequency can be detected stably, and the accuracy is significantly improved.

(2) Since it is almost unaffected by the opening and closing of the door or external impact, the accuracy of weight measurement is improved in this respect as well.

(3) Since the method measures the vibration frequency, even if the amount of displacement of the elastic body is small, it can be accurately detected, and the main body structure can be made compact.

(4) By measuring the weight of the object to be heated, the heat source is controlled via the control unit, so it is possible to heat the object for the optimum time without setting the heating time each time, making it convenient and easy to use.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an embodiment of the present invention;
Figure 2 is a schematic diagram equivalently showing the same elastic system, Figure 3 is a weight characteristic diagram showing the relationship among M ₁ , K ₁ , M ₂ , K ₂ , and Figure 4 is a diagram showing the vibration detection and waveform. FIG. 3 is an electronic circuit diagram that performs shaping processing. 1... Heating chamber, 2... Door, 3... Heated object, 4... Rotating plate, 5... Rotating mounting table, 6... Opening, 7... Motor, 8... Block A, 9...
Leaf spring, 10... Block B, 11... Bottom of main body, 12... Supporting material, 13... Detection coil, 1
4...pressure lever, 15...leg, 16...spring B.

Claims (1)

[Claims] 1. A heating chamber for storing an object to be heated, a heating means for heating the object to be heated in the heating chamber, a mounting table on which the object to be heated is placed, an elastic body supporting the mounting table, and the It has a main body that supports an elastic body, and by detecting the vibration frequency of the elastic body, the weight of the object to be heated is detected, and the output, heating style, and heating time of the heat source are determined in accordance with the detected weight. A cooking appliance with a weight detection function, in which the elastic constant of the elastic body is set so that the frequency band of the elastic body in the measurement range of the detected weight avoids the natural frequency band of the main body. .