JP2698184B2 - Electric device having a turntable - Google Patents

Description

The present invention relates to an electric device such as a microwave oven having a turntable.

(B) Prior art JP-A-64-3425 discloses that after the start of drive control of a motor for driving a turntable, the rotation time of the turntable is rotated by one natural number times substantially one natural number. A microwave oven for ending drive control is disclosed. In this case, the position of the food placed on the turntable in the heating chamber is the same at the end of heating, and therefore, when the food is placed on the front turntable in the heating chamber where the food is easily placed. Can be easily taken out.

However, there is no problem if the one turn time of the turntable is 10.5 seconds or 10.0 seconds, but if the one turn time is 10.00975 ... seconds and the decimal part continues for a long time, Actions must be taken, such as rounding to some decimal place. When the rounding process is performed in this manner, the one-turn time is not accurate for the turntable to make one turn, and has a slight error. Thus, in a configuration in which the drive control of the motor is terminated at the time when this one rotation time is substantially multiplied by a natural number under one rotation time having this error, the error is multiplied by a natural number at the end. A large error occurs, and the turntable deviates considerably from a state where the turntable rotates several times naturally. This means that even if the food is placed on the turntable in the front of the heating chamber in which the food is easily placed, it cannot be easily taken out.

(C) Problems to be Solved by the Invention The present invention provides a configuration in which the drive control of the motor is terminated at the time when the rotation time of one turn of the turntable is substantially a natural number times multiple times. Even when the motor is driven, the turntable can be rotated almost naturally several times at the end of the drive control of the motor.

(D) Means for Solving the Problems The electric device of the present invention includes a storage, a turntable arranged in the storage, and configured to rotate an object placed thereon,
A motor for driving the turntable, after the start of drive control of the motor, end means for terminating the drive control of the motor at a time when the rotation time of one turn of the turntable makes a substantially natural number times, A change means for changing the one-rotation time every time the one-rotation time is multiplied by a predetermined natural number during the drive control.

(E) Operation During the drive control of the motor driving the turntable, the rotation time is changed every time the rotation time of the turntable is multiplied by a predetermined natural number. Even if it is performed, it is controlled that the error due to this measure becomes large at the end of the drive control of the motor, and at the end of the drive control of the motor, the turntable is rotated almost naturally several times.

(F) Embodiment FIG. 1 shows the structure of a microwave oven according to an embodiment of the present invention. A turntable 4 for rotating a mounted object, that is, a food 3 is placed on the bottom of the storage or heating chamber 2 to which microwaves are supplied from the magnetron 1. The turntable is engaged and connected to an output shaft 6 of a synchronous motor 5 with a built-in speed reducer fixed below the heating chamber 2, and the turntable 4 is rotated by driving the synchronous motor 5.

FIG. 2 shows the circuit of the microwave oven. A microcomputer 7 is provided as a control unit for controlling the microwave oven. The computer inputs a desired signal from a keyboard 8 for setting heating conditions and the like, and also inputs a 60 Hz pulse having the same frequency as that of a 60 Hz commercial power supply 10 from a pulse generator 9 to operate the magnetron 1 to perform microwave heating. Drive control is performed, and drive control of the motor 5 is performed to rotate the turntable 4.

FIG. 3 shows the flow of the control program of the microcomputer 7, and the operation of the microwave oven will be described in detail with reference to FIG.

When the power to the microwave oven is turned on, the S1 step is first executed, and the heating condition is set on the keyboard 8 to wait for the start key to be operated.

When the microwave heating is performed, for example, when a desired heating time is set on the keyboard 8 and the start key is operated, steps S2, S3, and S4 are sequentially performed. S2
In the step, the counters K1 and K2 in the computer 7 are set.
And the flags F1 and F2 are reset. In step S3,
The magnetron 1 is driven to start microwave heating, and the motor 5 is driven to start rotating the turntable 4. In step S4, measurement of the elapsed time of the heating is started.

Next, step S5 is executed, and it is determined whether the heating time thus measured has reached the desired heating time set as described above. In this case, a negative determination is made in step S5, then steps S6, S7, and S8 are executed, and then steps S5 to S8 are cyclically executed. In step S6, each time a power frequency pulse signal input from the pulse generator 9 is generated, such a pulse is counted by the counter K2. In step S7, it is checked whether or not the flag F2 has been reset. In step S8, it is determined whether or not the count content of the counter K2 has reached 600.

Here, the count content of the counter K2 being 600 means that 60 seconds of the 60 Hz pulse have been generated 600 times and 10 seconds have elapsed. On the other hand, when the frequency of the applied commercial power supply is constant, the synchronous motor 5 has a characteristic that the rotation speed is constant, and the rotation time during which the turntable 4 makes one rotation is constant. In this case, it is assumed that one rotation time of the turntable 4 actually lasts for a long time after the decimal point, for example, 10.00975... Seconds. It is assumed that Therefore, as described above, the count content of the counter K2 is
At the time point when the number reaches 600, the turntable 4 is rotated once for convenience.

In the cyclic execution state of steps S5 to S8, when the count of the counter K2 after 10 seconds has reached 600, the steps S9, S10, S11, and S12 are sequentially executed. In step S9, the counter K2 is reset. In step S10, it is checked whether or not the flag F1 has been reset. In step S11, the counter K1 is set to 1
Is added. In step S12, it is determined whether or not the count content of the counter K1 has reached 14. When it is determined that the count content has reached 14, the one rotation time has repeatedly elapsed 14 times.

In this case, the content of the counter K1 is not 14;
Each step of S9 to S12 is executed every time the count value of the counter K2 reaches 600 while the steps of S8 are cyclically executed.

At the time when the content of the counter K1 becomes 14, the one-turn time is 10 seconds, which is determined for convenience, and is slightly smaller than the actual one-turn time. From this, it will be in a state of rotating slightly less. In view of this, the following control is performed.

That is, when the content of the counter K1 becomes 14, S13, S1
4. Each step of S15 is executed. In step S13,
The counter K1 is reset. In step S14,
The flag F2 is set. In step S15, it is determined whether or not the count content of the counter K2 has reached 601. The fact that the count content of the counter K2 is 601 means that 60 times of the 60 Hz pulse has been generated 601 times and a time slightly longer than 10 seconds has elapsed, and the rotation time of the turntable 4 is slightly longer. Means that Then, steps S5, S6, S7, and S15 are cyclically executed, and the count of 601 is awaited. At the time of the count of 601, one turn of the turntable 4 is determined based on the elapse of the slightly longer one-turn time. As a result, the content of the counter K1 becomes 14, and the state in which the turntable 4 has been rotated slightly slightly from the state in which the turntable 4 has just rotated 14 times becomes a state in which the turntable 4 has just rotated 15 times when one rotation time has elapsed. is there.

Thus, when the count of 601 is performed, step S16 is executed, and the counter K2 and the flag F2 are reset. After that, as is now clear, the steps S5 to S8 are circulated until the content of the counter K1 becomes 14, and each of the processes of S9 to S12 is performed every time the content of the counter K2 reaches 600. The process is repeated from the state where the step is executed.

Then, when the currently measured heating time reaches the desired heating time set as described above, the above-described repetition ends in step S5, and then steps S17 and S18 are executed. In step S17, the driving of the magnetron 1 is stopped to end the microwave heating, and the measurement of the heating time is ended and the contents are reset. In step S18, the flag F1 is set.

Thereafter, in a situation where the counter K2 has counted 600 when the time has reached, steps S5 to S8 are cyclically executed, and steps S9 and S10 are executed based on the count of 600, and the flag F1 is set. , The step S19 is then executed. In this step, the drive of the motor 5 is stopped and the turntable 4
Stops rotating.

Here, the turntable 4 stops rotating in a state in which one rotation time is multiplied by a natural number while changing one rotation time every time one rotation time is multiplied by a predetermined natural number 14. Therefore, even if one rotation time is determined to be 10 seconds for convenience as described above, the turntable 4 has rotated a natural number of times with little deviation when the rotation is stopped.

As a result, the position of the food 3 placed on the turntable 4 in the heating cabinet 2 becomes the same at the end of heating, and therefore, the forward turntable in the heating cabinet 2 in which the food 3 is easily placed. When it is placed on the top 4, it can be easily taken out.

(G) Effects of the Invention According to the present invention, in the configuration in which the drive control of the motor is terminated at the time when the turntable one rotation time is multiplied by a substantially natural number, a measure such as rounding off the one rotation time is performed. Even when the motor is driven, the turntable can be rotated almost naturally several times without error, and when the object is placed on the turntable on which the object is easily placed, the object can be easily taken out.

[Brief description of the drawings]

1 is a front sectional view, FIG. 2 is a circuit diagram, and FIG. 3 is a flowchart of a control program. 2 ... heating chamber, 4 ... turntable, 5 ... synchronous motor, 7 ... microcomputer.

Claims (1)

(57) [Claims] 1. A storage, a turntable disposed in the storage, for rotating an object to be placed, a motor for driving the turntable, and after starting the drive control of the motor,
Terminating means for ending the drive control of the motor at a time when the rotation time of the turntable makes one rotation is substantially a natural number, and at each time when the rotation time is multiplied by a predetermined natural number during the drive control of the motor. An electric device having a turntable comprising the change means for changing one rotation time.