JPH0211819B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a cooking device that detects the weight of food and controls the heating time, heating temperature, heating output, heating pattern, etc. according to the weight.

Structure of conventional example and its problems An example of a conventional heat cooker with a weight detection function is a high-frequency heating device disclosed in Japanese Patent Application Laid-open No. 160742/1983. Figure 1 shows this high frequency heating device. In FIG. 1, there is a heating chamber 2 for storing food 1, and a door 3 which can be opened and closed for taking in and taking out the food is provided in front of the heating chamber 2. The entire main body is covered by a body 4. A magnetron 5 that oscillates high frequency waves is provided to heat the food 1. The food 1 is placed on a mounting table 6, and its load is supported by a shaft 16 and held by a spring 7. This spring 7
is supported by rollers 10 and is rotatable. The frequency of the spring 7 changes in response to the load of the food 1. A weight detection magnet 8 is fixed to the vibrating portion of the spring 7, and its vibration is detected by a detection coil 9. The rotational drive upper magnet 11 and the rotational drive lower magnet 12 are for rotating the mounting table 6, and the rotational drive lower magnet is fixed to a pulley 13. By applying a rotational force to the pulley 13, the rotational force is transmitted to the mounting table 6 by the attractive force of the upper rotational drive magnet 11 and the lower rotational drive magnet 12. Now, the weight of the food 1 is detected by the above configuration, and the main part thereof is shown in FIG. In FIG. 2, the loads of the food 1, the mounting table 6, and the shaft 16 are applied to the spring 7. Since the spring 7 is an elastic body, it generates vibration, and its frequency is correlated with the load, so
By detecting the frequency, the weight of the food 1 can be detected. Then, the output of the magnetron 5 is controlled based on the detected weight, and heating can be performed according to the weight of the amount of food, so the user does not need to set the heating time or heating output, and the cooking performance can be improved. It has the advantage of improving.

However, in actual use, the food 1 is placed on the placing table 6 with the door 3 open, but at that time, the food to be cooked is not necessarily placed at once, but twice. In some cases, it is placed in three parts. Therefore, it is necessary to constantly track and measure the changing weight of food. Further, when the device is placed, the load on the spring 7 may change, causing temporary unstable vibrations, making accurate weight measurement impossible. Furthermore, the generated vibrations may attenuate and stop, so it is necessary to always detect when stable vibrations are occurring and perform weight detection at that time.

As described above, in the conventional method, it is necessary to detect the occurrence of stable vibrations in order to accurately measure the weight of food. That is, functions such as an operation that follows weight changes, an operation that does not incorporate unstable vibrations, and an operation that detects vibration attenuation are required, and in order to actually achieve these functions, a considerable number of configurations are required. In addition, if these operations are not performed, the weight of the food cannot be accurately detected, which may cause the heating time and heating output to be incorrect.
The food will be undercooked.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to accurately detect the weight of food with a simple configuration and enable stable heating and cooking.

Structure of the Invention In order to achieve the above object, the heat cooker with a weight detection function of the present invention is provided with an excitation device to generate stable vibrations, and furthermore, by delaying the capture of the generated vibrations by the excitation device for a certain period of time. This has the effect of being able to detect weight when it is in a stable vibration state. In particular, the generation of vibrations is linked to the movement of the door from the open state to the closed state, so the door is closed when the weight is being loaded. This means that it is not possible for the user to change the amount of food in the heating chamber;
The amount of food in the heating chamber is therefore the final state in which cooking is to be carried out. It is most desirable to detect the weight of the food at this time. Furthermore, a door switch is provided to detect the open/closed state of the door, detect the change from the open state to the closed state of the door, and then detect the weight after a certain period of time when stable vibration is occurring.

With the above configuration, by capturing the weight of the food to be cooked when stable vibrations are occurring, it is possible to follow complex weight changes, prevent unstable vibrations, and damp vibrations. This has the effect that it is possible to easily and accurately detect the weight of food without requiring any detection operation.

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

FIG. 3 shows an external perspective view of a microwave oven which is a high frequency heating device as an embodiment of the present invention. 2 is a heating chamber, a door 3 which can be freely opened and closed is provided on the front side of the heating chamber, and 4 is a body that covers the main body. A display section consisting of a fluorescent display tube or light emitting diode is installed on the front to display heating output, heating time, food weight, etc., and near it, you can set the heating time, heating output, cooking menu, and start cooking. An operation input section is provided to instruct the engine to stop or stop.

FIG. 4 shows a side sectional view showing the structure of this microwave oven. In FIG. 4, a heating chamber 2 for storing food 1 is provided, and a door 3 that can be opened and closed for taking food in and out is provided in front of the heating chamber 2. A magnetron 5 that generates high frequency waves to heat the food 1 is provided. A mounting table 6 is provided inside the heating chamber 2 for placing the food 1, the food 1 and the mounting table 6 are supported by a shaft 16, and the load is held by a vibration-side spring spacer 17. This vibration side spring spacer 17 is connected to a fixed side spring spacer 18 via a plurality of leaf springs 19. FIG. 5 shows a perspective view of the main parts of the plate spring 19, the vibration-side spring spacer 17, and the stationary-side spring spacer 18 in an attached state. As shown in FIG. 5, the vibration-side spring spacer 17 and the fixed-side spring spacer 18 are sandwiched between leaf springs 19, and the leaf springs 19 are fixed in a parallel state.

As shown in FIG. 3, the fixed spring spacer 18 is fixed to the bottom plate 20 of the heating chamber. With the above configuration, the portion supported by the vibration-side spring spacer 17 vibrates. The frequency changes depending on the load applied to the leaf spring 19. Therefore, by detecting this frequency, the weight of the food 1 is detected. A weight detection magnet 8 and a detection coil 9 are used as means for detecting vibration. That is, the weight detection magnet 8 is attached to the vibrating part, while the detection coil 9 is attached to the stationary side. Weight detection magnet 8 by vibration
The distance between the sensing coil 9 and the sensing coil 9 changes, and the magnetic field strength at the sensing coil 9 changes correspondingly. An alternating current electromotive force corresponding to changes in magnet strength is generated in the detection coil 9, and the frequency of the electromotive force can be detected and processed by an electronic circuit or a so-called microcomputer. Therefore, an excitation lever 21 for applying vibration to the vibrating part is provided, and force is applied to the vibrating arm 22 of the vibrating part in conjunction with the opening/closing operation of the door 3 to generate vibration. An enlarged view of the main part of this part is shown in Fig. 6. That is, when the door 3 is opened and closed, the excitation lever protrusion 24 of the excitation lever 21 applies force to the excitation arm 22, thereby generating vibration in the vibrating section. By doing this, door 3
Stable vibration occurs when the device changes from open to closed, allowing accurate weight detection. For this purpose, a door switch 23 is provided as shown in FIG. 3 to detect whether the door is open or closed.
Then, by detecting the change of the door 3 from the open state to the closed state by the door switch 23, and detecting the weight from the vibration in synchronization with this change, when stable vibration is occurring, Moreover, the final amount of food to be cooked can be accurately measured.

FIG. 7 shows an embodiment of a processing circuit for alternating current electromotive force generated in the detection coil 9. That is, an electromotive force is generated in the detection coil 9 in response to the vibration of the weight detection magnet 8. Since the electromotive force is small, the amplifier circuit 2
Amplify by 5. The amplified signal includes radio wave noise and other vibration components different from the frequency of the weight detection magnet 8. Therefore, filter circuit 2
6, a circuit is provided to cut off frequencies other than those for weight detection. The waveform that has passed through the filter circuit 26 is then shaped into a square wave by a waveform shaping circuit 27 to make it a processable waveform. This square wave is then processed by a microcomputer or the like.

FIG. 8 shows the signal of the door switch 23 for detecting the open/closed state of the door 3 and the vibration of the mounting table. That is, when the door 3 is closed, the door switch 23 changes from OFF to ON. At the same time, vibration is generated in the vibration section by the vibration lever 21 in conjunction with the closing operation of the door 3. The vibration of the vibrating part, that is, the mounting table 6, is unstable at first, as shown in the figure. The original diagram of this is that the vibration lever 21 applies force to the vibrating part, causing temporary unnatural vibrations. Still another cause is that when the door 3 is closed, the door 3 collides with the front surface of the heating chamber 2, and at that time abnormal vibrations are generated, which affect the vibrating part of the vibrating part. i.e. door 3
The moment it closes, it ceases to be a stable free vibration. However, after a certain period of time, it becomes a stable free vibration. Therefore, as shown in the figure, weight detection is masked for a certain period of time _TM after the door switch 23 is turned on, and detection is performed after _TM . By doing so, more stable and accurate weight can be detected.

FIG. 9 shows an embodiment of a control circuit for a heat cooker with a weight detection function according to the present invention. A magnetron 5 is provided with a high voltage transformer 28 that generates a high voltage to operate the magnetron, and a cooling fan motor 29 that cools the magnetron 5. Output control relay 30 and operation control relay 31
is a relay for controlling the output of the magnetron 5, and is operated by a signal from the microcomputer 32. 33 is a basic oscillation circuit, and the microcomputer 32 generates basic pulses for operation. The microcomputer 32 has functions such as calculation, judgment, input, and output control, and performs complex control, and is called an electronic brain. Therefore, it is easy to detect the change of the door 3 from the open state to the closed state by the door switch 23, and simultaneously detect the vibration of the weight detection magnet 8 using the output waveform of the waveform shaping circuit 27. It can be achieved.

Furthermore, the microcomputer 32 can easily count the constant time T _M from the signal of the door 23 when the door 3 is closed.

FIG. 10 shows a flow chart showing the operation of the microcomputer 23.

As described above, according to this embodiment, it is possible to accurately detect the weight of food, and it is possible to realize optimal heating and cooking according to the amount of food.

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

(1) Since the device is configured to capture the weight after generating vibrations and masking them for a certain period of time, it is possible to detect the weight while stable vibrations are occurring, making it possible to accurately detect the weight of food. This enables optimal cooking.

(2) The device generates vibrations when the door closes and captures the weight in synchronization with the vibrations, so stable vibrations are generated and the weight of the food can be accurately detected. This allows optimal cooking.

(3) By generating vibration due to the door closing operation, detecting the door closing timing with a door switch, and masking the vibration for a certain period of time after detecting the door closing timing,
Since it is only necessary to perform the weight detection operation at this timing, a complicated weight detection operation is not required, and the weight can be easily and reliably captured.

(4) Since the door is closed, the weight of the food is the final weight that will be cooked. Therefore, it is most ideal to take in weight at this timing.

(5) Since the timing of loading the weight is detected by the door switch, it is easy to realize the weight loading operation.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the structure of a conventional microwave oven as a heat cooker with a weight detection function, Fig. 2 is a sectional view of a mounting table as a weight detection part, and Fig. 3 is a weight detection function of the present invention. A perspective view of the appearance of a microwave oven as an additional heat cooker, FIG. 4 is a sectional view showing its structure, FIG. 5 is a partial perspective view of the weight detection section, FIG. 6 is a sectional view thereof, and FIG. signal processing circuit diagram,
FIG. 8 is a timing diagram showing the relationship between the door switch signal and the vibration state of the vibrating section, and FIG. 9 is a control circuit diagram of a microwave oven as an embodiment of the present invention.
FIG. 10 is a flow diagram showing the operation of the microcomputer. 1...Food, 2...Heating chamber, 3...Door, 4
... Body, 5 ... Magnetron, 6 ... Mounting table, 7 ... Spring, 8 ... Weight detection magnet, 9 ...
Detection coil, 10... Roller, 11... Upper magnet for rotational drive, 12... Lower magnet for rotational drive, 1
3... Pulley, 14... Display section, 15... Operation input section, 16... Shaft, 17... Vibration side spring spacer, 18... Fixed side spring spacer, 19... Leaf spring, 20... Heating chamber bottom plate, 21...excitation lever,
22... Excitation arm, 23... Door switch,
24...Excitation lever protrusion, 25...Amplification circuit, 2
6... Filter circuit, 27... Waveform shaping circuit,
28... High voltage transformer, 29... Cooling fan motor, 30... Output control relay, 31... Operation control relay, 32... Microcomputer,
33...Basic oscillation circuit.

Claims (1)

[Scope of Claims] 1. A heating chamber for storing food, a heat source for heating the food in the heating chamber, a door that can be opened and closed for taking food in and out of the heating chamber, and a door on which the food is placed. a placing table; an elastic body that supports the placing table and vibrates in accordance with the weight of the food; a detection unit that detects the vibration of the elastic body; and a detection unit that detects the weight of the food from the vibration of the elastic body detected by the detection unit. A configuration comprising a weight detection section for detecting the food and an excitation device for generating vibration in the elastic body, and the weight detection section detects the weight of the food after a certain time delay after the excitation device vibrates the elastic body. A heat cooker with a weight detection function. 2. The heat cooker with a weight detection function according to claim 1, wherein the excitation device is configured to operate in synchronization with the opening/closing operation of the door. 3. A door switch for detecting the open/closed state of the door is provided, and the weight detection section is configured to operate after a certain time delay from the time when the door switch detects a change in the open/closed state of the door. Heat cooker with weight detection function.