JP2791846B2 - microwave - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven, and more particularly to a microwave oven having a turntable and a piezoelectric weight sensor.

[0002]

2. Description of the Related Art A schematic perspective view of a conventional microwave oven of this type is shown in FIG. In the figure, reference numeral 31 denotes a main body of a microwave oven. A heating chamber 33 is formed in the main body 31, and a door 34 is provided on a front surface of the heating chamber 33. In addition, heating room 3
A turntable 35 is disposed at the bottom of the turntable 3. The turntable 35 is rotated by rollers 36 in order to uniformly heat the food placed on the turntable 35. It is designed to pass while rotating. In the drawing, reference numeral 38 denotes a control unit, which can perform control such as setting of a heating time.

[0003] In the microwave oven configured as described above, when the food in the heating chamber 33 is taken out after the cooking is completed, the turntable 35 may be stopped at a place where the food is far from the user. There was a problem that it was difficult to take out food.

An example for solving the above problem is disclosed in Japanese Patent Publication No. 64-3425. The publication discloses that a fixed position stop function of the turntable 35 is mounted on a microwave oven so that the turntable 35 is stopped at the same position as at the start of cooking after cooking is completed. Therefore, the time required for the turntable 35 to make one round is calculated in advance (for example, 60 times).
(20 seconds at 50 Hz and 24 seconds at 50 Hz), and at the end of cooking, the turntable 35 is stopped at a fixed position by continuing to rotate the turntable 35 until it becomes an integral multiple of the above time.

[0005]

However, in the above-mentioned conventional microwave oven, the time required for the turntable 35 to make one round is determined, and the time is determined by continuing to rotate the turntable 35 by an integral multiple of the time. Since the stop is considered to be at the position, there is a problem that, when the mechanical rotation of the turntable 35 becomes uneven, the error in the stop position increases as the cooking time increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a microwave oven capable of stopping a turntable at the same position as when cooking was started, regardless of the length of cooking time. The purpose is.

[0007]

In order to achieve the above object, a microwave oven according to the present invention reduces the weight of a food placed on the turntable by passing through a plurality of rollers for supporting and rotating the turntable. In a microwave oven having a weight sensor for detecting, the position of the turntable at the start of cooking is detected based on the timing at which the rollers pass through the weight sensor, and after the cooking is completed, the turntable is stopped at the cooking start position. It is characterized by having turntable control means.

[0008]

According to the above arrangement, the position of the turntable at the start of cooking is detected based on the timing at which the rollers pass through the weight sensor. Thus, the turntable can be stopped.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the microwave oven according to the present invention will be described below with reference to the drawings. The hardware configuration of the embodiment is shown in FIG.
The description of the hardware configuration is omitted here.

FIG. 1A is a diagram showing an electromotive force waveform and a turntable signal in the weight sensor 37 of the microwave oven according to the embodiment, and FIG. 1B is a diagram showing a roller 36 for explaining (a). FIG. 3 is a schematic plan view showing a positional relationship with a weight sensor 37. Normally, the weight sensor 37 detects the weight of the food placed on the turntable 35, and measures the weight of the food as the roller 36 passes over the weight sensor 37. In this embodiment, the turntable 35 is driven as follows. First, the time until the roller 36 first passes the weight sensor 37 from the start of cooking, that is, the time ΔT until the electromotive force waveform appears, is measured and stored. The time from the first electromotive force waveform generation to the next electromotive force waveform generation, that is, 1/3 rotation time T, is also measured and stored. Then, the number of electromotive forces generated by the rotation of the turntable 35 due to the progress of cooking is counted. When the cooking time becomes zero, the heating is usually stopped, and the turntable signal is also turned off. In the present invention, however, the turntable signal is input in order to keep the turntable 35 rotating to the same position as when cooking was started. The state is maintained a little more. Further, (T−
At that point, the turntable signal is turned off, and the turntable 3 is turned off.
5 is stopped.

FIG. 2 shows a flowchart of the control of the rotation operation of the turntable 35 by the control unit 38. First, the microwave oven is operated to start cooking (step 1). Next, it is determined whether or not the electromotive force waveform shown in FIG. 1 is detected by the weight sensor 37 (step 2). If it is determined that the electromotive force waveform is not detected, the process returns to step 2 again. The determination as to whether or not the electromotive force waveform is detected is repeated. If it is determined that the other electromotive force waveform has been detected, the process proceeds to step 3, where the time ΔT from the start of cooking until the electromotive force waveform is detected is calculated and stored. It is determined whether the next electromotive force waveform has been detected (step 4). If it is determined that the electromotive force waveform has not been detected, the process returns to step 4 again to determine whether the electromotive force waveform has been detected. Is repeated. When it is determined that the electromotive force waveform is detected in step 4, the process proceeds to step 5, and
The time T from when the electromotive force waveform is detected until when the electromotive force waveform is detected is calculated and stored. It is determined whether the next electromotive force waveform has been detected (step 6). If it is determined that the electromotive force waveform has not been detected, the process returns to step 6 again. When it is determined that the electromotive force has been detected, the process proceeds to step 7, and it is determined whether the electromotive force waveform of the second cycle has been detected. If it is determined that the electromotive force waveform of the second round has not been detected, the process returns to step 7 again, and the determination of whether the electromotive force waveform of the second round has been detected is repeated. Is detected, the electromotive force passing through the roller 36 is continuously detected by the weight sensor 37, and cooking is executed (step 8). Then, after a certain period of time, it is determined whether or not the cooking has been completed (step 9). If it is determined that the cooking has not been completed, the process returns to step 8, and the cooking is continued as it is. If it is determined that the cooking has been completed, the process proceeds to step 10, where the turntable signal is maintained in the ON state, and it is determined whether the number of generated electromotive forces is a multiple of three. If it is determined that the number of generated electromotive forces is not a multiple of three, the process returns to step 10 again, and it is repeatedly determined until the number of generated electromotive forces becomes a multiple of three, and it is determined that the number of generated electromotive forces is a multiple of three. In this case, it is then determined whether or not the turntable 35 has been further rotated for (T-ΔT) time (step 1).
1). If it is determined that the turntable 35 has been rotated for (T−ΔT) time, the turntable signal is
FF is performed, and the turntable 35 is stopped (step 1).
2) If it is determined that the turntable 35 has not been rotated for the time (T-ΔT), the process returns to step 11 again, and the determination is repeated until the turntable 35 is rotated for the time (T-ΔT).

According to this embodiment, the weight sensor 37 has a function of detecting the timing of the electromotive force generated when the roller 36 passes, in addition to the function of measuring the weight of food, which is a normal operation. Cooking is performed by detecting the timing of the electromotive force, and the turntable signal is maintained in the ON state for a while even after the completion of cooking. Further, from the time when the number of electromotive force generation becomes a multiple of 3, the time ΔT from the time of starting cooking to the time of first electromotive force generation is calculated from the time T from the time of the first electromotive force generation to the time of next electromotive force generation. The turntable 35 is rotated only for the time subtracted, that is, (T-ΔT) time, and after the turntable 35 is rotated for (T-ΔT) time, the turntable signal is turned off. Therefore, the turntable 35 can always be stopped accurately at the same position as when cooking was started.

The weight sensor 37 includes a roller 36.
And a piezoelectric type that generates a voltage.

[0014]

As described in detail above, in the microwave oven according to the present invention, the weight of the food placed on the turntable is detected by passing through a plurality of rollers that support and rotate the turntable. In a microwave oven having a weight sensor, a turntable for detecting a position of the turntable at the start of cooking by timing when the roller passes the weight sensor, and stopping the turntable at the cooking start position after cooking is completed. Since the control means is provided, the turntable can be stopped at the same position as when the cooking was started after the completion of the cooking, regardless of the length of the cooking time. Therefore, it is easy to take out the food from the heating chamber, and the usability can be improved.

[Brief description of the drawings]

FIG. 1A is a diagram showing an electromotive force waveform and a turntable signal in a weight sensor of a microwave oven according to an embodiment, and FIG. 1B is a diagram illustrating a roller and a weight sensor for explaining (a). It is the schematic plan view shown.

FIG. 2 is a flowchart illustrating control of the rotation operation of the turntable by the control unit of the microwave oven according to the embodiment.

FIG. 3 is a schematic perspective view showing a microwave oven.

[Explanation of symbols]

 35 turntable 36 roller 37 weight sensor 38 control unit (turntable control means)

Claims (1)

(57) [Claims] 1. A microwave oven having a weight sensor for detecting the weight of food placed on the turntable by passing through a plurality of rollers that support and rotate the turntable, wherein the rollers pass through the weight sensor. A microwave oven comprising: a turntable control means for detecting a position of the turntable at the start of cooking based on the timing of the start, and stopping the turntable at the cooking start position after the completion of cooking.