JPS6352292B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a yagura kotatsu in which the power supply to a heating element provided on the yagura kotatsu main body can be wirelessly controlled by an operation unit provided on a table board.

<Prior art> Conventional Yagura kotatsu, for example, a Yagura kotatsu in which a control circuit that controls the energization of a heating element provided in the main body of the Yagura kotatsu is operated by an operation part provided on a table board, has an operation part on the table board and the above-mentioned Yagura kotatsu. It is constructed by connecting the control circuit of the Gurakotatsu body with a lead wire (cord), so when using the kotatsu futon on the Yagura Kotatsu body, the lead wires get in the way and the table board cannot be used freely. There was a drawback that it could not be placed in the correct direction.

<Objective> The object of the present invention is to provide a yagura kotatsu that eliminates the above-mentioned drawbacks.

<Example> An example of the tower kotatsu of the present invention will be described below with reference to the drawings.

The Yagura Kotatsu of the present invention is constructed as shown in the drawings, and in FIG.
), and the oscillation frequency changes depending on the voltage of the capacitor 13. The oscillation output of the VCO 1 is generated between an electrode plate 11A provided on the yagura kotatsu main body 11 and an electrode plate 12A provided on the table board 12 placed on the yagura kotatsu main body 11 so as to face the electrode plate 11A. Capacitance generated in (stray capacitance)
It is applied to the variable resonant circuit 10 provided on the table plate 12 through wireless connection via capacitor coupling by _CA. The variable resonant circuit 10 is formed of a capacitor, a coil, etc., and the resonant frequency is varied by operating the capacitance of the capacitor or the inductance of the coil using an operating section provided on the table plate 12. This is what I did. The resonance signal of the variable resonance circuit 10 is transmitted to the electrode plate 12B provided on the table board 12 and the tower kotatsu main body 11 facing the electrode plate 12B.
Due to the capacitance (stray capacitance) C _B generated between the electrode plate 11B and the electrode plate 11B, the voltage is connected wirelessly through capacitor coupling and is applied to the detector 2 provided on the tower kotatsu main body 11. An amplifier circuit 3 for amplifying the output signal of the detector 2 is connected to the detector 2 . A detection circuit 4 is connected to the amplifier circuit 3 for detecting the output signal of the amplifier circuit 3 (cutting out high frequencies). The detection circuit 4 includes a minimum value detection circuit 5 that determines that the variable resonance circuit 10 is in a resonant state at the resonant frequency when it detects that the output signal of the detection circuit 4 [shown in FIG. 2A] has reached the minimum value. is connected. Until the minimum value detection 5 detects the minimum value, the output is at a high level (power supply voltage) and charges the capacitor 13 through the resistor 14, the voltage of the capacitor 13 rises, and the oscillation frequency of the VCO 1 also rises, and When the lowest value is detected, the output becomes a low level (earth potential) and is connected to the capacitor 1 via the resistor 14.
3 is discharged and the voltage of the capacitor 13 decreases to the above value.
The oscillation frequency of VCO1 also decreases. 6 is a limiter circuit connected to the capacitor 13, and when the voltage (potential) of the capacitor 13 rises and the oscillation frequency of the VCO 1 becomes higher than the variable range of the variable resonance circuit 10, the output of the limiter circuit 6 becomes a low impedance. When the capacitor 13 is discharged and reaches zero voltage, the output becomes high impedance and the capacitor 13 is charged again.
The voltage of the capacitor 13 is used as a reference voltage for temperature control, and the reference voltage is compared with the output voltage of the temperature detection section (not shown) of the temperature detection circuit, and based on the comparison result, the Yagura Kotatsu A temperature detection circuit 7 that changes the detected temperature inside is connected. A power control circuit 8 is connected to the temperature detection circuit 7, which controls energization of the heating element 9 according to the output of the temperature detection circuit 7 to maintain the temperature at the detected temperature.

In addition, in FIG. 2, FIG. 2A is the output waveform of the detection circuit 4 in FIG. 1, FIG. 2B is the voltage waveform of the capacitor 13 in FIG. 1, and FIG. 2C is the lowest value in FIG. 5 is an output waveform diagram of the detection circuit 5. FIG.

Next, the operating state of the tower kotatsu of the present invention constructed as described above will be explained.

First, set the resonant frequency f _p of the variable resonant circuit 10 of the table board 12, and when the oscillation frequency of the VCO 1 is lower than the resonant frequency f _p , the detection output of the detection circuit 4 is at the voltage V _D in FIG. 2A. Since it is not the lowest value, the output of the lowest value detection circuit 5 becomes a high level,
When the capacitor 13 is charged and the oscillation frequency of the VCO 1 rises and reaches the resonant frequency f _p , the second
As shown in FIG.
is discharged, the voltage of the capacitor 13 decreases, and the oscillation frequency of the VCO 1 also decreases. When the oscillation frequency decreases and deviates from the resonant frequency f _p , it also deviates from the minimum value, so the output of the minimum value detection circuit 5 becomes high level, charging the capacitor 13 and increasing the voltage of the capacitor 13. VCO1
Increase the transmission frequency and repeat the same operation.

As mentioned above, since the feedback of the VCO 1 is applied, the voltage of the capacitor 13 becomes a constant voltage proportional to the resonant frequency. Compare the output of the temperature detection section (not shown) and
When the output is higher than the reference voltage, the temperature detection circuit 7 outputs an output, and based on this output, the power control circuit 8 controls the energization of the heating element 9 to maintain the temperature inside the tower kotatsu constant. When the resonant frequency is varied by the variable resonance circuit 10, the constant voltage of the capacitor 13 changes, the reference voltage for temperature control changes, and the output ratio of the temperature detection circuit 7 changes, so the power control circuit 8 controls it. The energization rate to the heating element 9 also changes, and the temperature inside the tower kotatsu is controlled to a temperature corresponding to the resonant frequency varied by the variable resonant circuit 10.

In the above, the voltage of the capacitor 13 is used as the reference voltage for temperature control, and when the voltage becomes higher than this reference voltage, the temperature detection circuit 10 outputs an output, but when the voltage becomes lower than the reference voltage, the temperature The detection circuit 10 may be controlled to output.

<Effects of the Invention> Since the Yagura Kotatsu of the present invention has the above-described configuration, when the Yagura Kotatsu body is used with a kotatsu futon placed on it, the lead wires do not get in the way and the table board can be moved in any direction. Since only the variable resonant circuit that can be mounted and operated by the operation unit is provided on the table board, the space on the table board for the variable resonant circuit is used for the variable resistor, monostable multivibrator, and their power supply. It can be extremely small compared to a device including a temperature control signal generating means formed from a battery or the like. Therefore, there is no need to secure a special space for installing the variable resonant circuit, and the variable resonant circuit operated by the operation unit can be easily installed at a desired position on the table board. This eliminates the need for battery maintenance and inspection. Since the variable resonant circuit of the table board and the control circuit of the main body of the kotatsu are connected wirelessly by capacitor coupling, the temperature control signal generated by the temperature control signal generating means of the table board of the electric kotatsu is transmitted to the coil and iron core. Compared to the signal transmitted via a medium to the temperature control signal detection means provided on the electric kotatsu frame base, the Yagura kotatsu is subject to noise generated when controlling the temperature of surrounding equipment such as heating equipment such as electric carpets. This makes it possible to more reliably control the control circuit of the Yagura Kotatsu body using the operating section on the table board. Moreover, the space required for the table plate for providing the electrode plate for capacitor coupling is small, and the electrode plate can be easily provided at a desired position on the table plate.

Furthermore, since the impedance of the variable resonant circuit reaches its maximum when it is in a resonant state, if the resonance frequency is detected at the lowest value of the output voltage of the detector circuit, even if the output voltage of the detector circuit fluctuates due to external noise, the output voltage will not change. Fluctuations to the lowest value are extremely rare, and the influence of external noise can be minimized, malfunctions caused by the external noise can be prevented, and accurate temperature control can be performed.

[Brief explanation of drawings]

Figure 1 is a block diagram showing an embodiment of the tower kotatsu of the present invention, Figure 2A is an output waveform diagram of the detection circuit in Figure 1, Figure 2B is a voltage waveform diagram of the capacitor in Figure 1, FIG. 2C is an output waveform diagram of the lowest value detection circuit of FIG. 1. In the drawing, 9 is a heating element, 10 is a variable resonant circuit, 1
1 indicates the main body of the Yagura Kotatsu, and 12 indicates the table board.

Claims (1)

[Claims] 1. A variable resonant circuit whose resonant frequency changes according to the operation of the operating section is provided on the table board, a voltage controlled oscillation circuit whose oscillation frequency changes according to changes in applied voltage, and an oscillation frequency of the voltage controlled oscillator circuit. a detection circuit that detects the voltage via the variable resonance circuit, and a minimum value at which it is determined that the resonant frequency of the variable resonance circuit and the oscillation frequency of the voltage controlled oscillation circuit match when the output voltage of the detection circuit reaches a minimum value. a detection circuit, and a voltage that adjusts the voltage applied to the voltage controlled oscillation circuit so that the output of the minimum value detection circuit changes the oscillation frequency of the voltage controlled oscillation circuit in a direction that matches the resonant frequency of the variable resonance circuit. A control circuit consisting of an application means and a power control means for controlling energization to the heating element according to the voltage of the voltage application means is provided in the main body of the Yagura Kotatsu, and electrode plates are provided on the table board and the main body of the Yagura Kotatsu, respectively. A tower kotatsu characterized in that the control circuit and the variable resonance circuit are capacitor-coupled through the electrode plate.