JP2755870B2 - Cooker temperature detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting the temperature of a cooking device such as an electric pot, a rice cooker, a hot plate, a fryer, and an electric pot.

[0002]

2. Description of the Related Art Conventionally, there has been known a cooking device in which a cooking container is detached from a cooking device body so that the cooking container can be washed. In this type of cooker, a temperature sensing element (for example, a thermistor or a resistor) for detecting the temperature of the cooking container or the cooked product is fixed to the cooker body.

[0003]

However, the cooking device has a problem in that when the cooking container is removed from the cooking device body, foreign substances such as water, oil and dust adhere to the temperature sensing element. In addition, if the temperature-sensitive element is covered with a protective cover in order to prevent foreign matter from adhering, the detection accuracy of the temperature-sensitive element is reduced, and particularly when the heat capacity of the cooking vessel is large, the detection accuracy is extremely reduced. Was. Furthermore, the temperature inside the container could not be directly measured.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first invention is directed to a cooking device main body, and a detachable or openable / closable contact / separation member for the cooking device main body. In the temperature detecting device for a cooker comprising: a temperature-sensitive means whose electrical characteristics change in accordance with the temperature; and a secondary coil forming a series closed circuit together with the temperature-sensitive means. A primary coil and a mutual induction action of the primary coil and the secondary coil in the cooking device main body.
A high-frequency generating means for inducing a current in the secondary coil;
Temperature detecting means for obtaining the temperature of the contact / separation member from the level of current flowing through the secondary coil.

Next, a second aspect of the present invention relates to
A secondary coil, a rectifier for rectifying a current flowing through the secondary coil, a power storage for storing electric charge flowing through the rectifier, and an electrical characteristic that changes according to temperature. Operating temperature sensing means, and control means for outputting a high-frequency current corresponding to a change in the electrical characteristics of the temperature sensing means to the secondary coil,
A primary coil, high-frequency generating means for inducing a current in the secondary coil by a mutual induction action of the primary coil and the secondary coil, and a high-frequency generating means for inducing a current in the primary coil by the mutual induction action. Temperature detecting means for determining the temperature of the contact / separation member from the characteristics.

Next, a third aspect of the present invention relates to the above-mentioned contact / separation member,
A vibrator whose vibration level changes in accordance with a temperature change of the contact / separation member; and a secondary coil forming a series closed circuit together with the vibrator. High frequency generating means for inducing a current in the secondary coil by mutual induction between the primary coil and the secondary coil, and temperature detecting means for obtaining the temperature of the contact / separation member from the oscillation frequency of the high frequency generating means are provided. Things.

It is preferable that one of the primary coil and the secondary coil is arranged so that one of them is located around the other in the cooking state.

[0008]

In the temperature detecting device for the contact / separation member according to the first aspect of the present invention, when a high-frequency current is output from the high-frequency generating means to the primary coil, the high-frequency current is output based on the mutual induction between the primary coil and the secondary coil. A current is induced in the secondary coil, and a current flows to the temperature sensing means. The electrical characteristics of the temperature sensing means change according to the temperature of the contact / separation member, and the impedance in the circuit on the contact / separation member side changes. Further, the change in the impedance is detected by the temperature detecting means, and the temperature of the contact / separation member is obtained.

Next, in the temperature detecting device for the contact / separation member according to the second invention, when a high-frequency current is output from the high-frequency generating means to the primary coil, the mutual induction between the primary coil and the secondary coil is reduced. A high-frequency current is induced in the secondary coil based on this. This high-frequency current is rectified into direct current by the rectifier, and the electric charge is stored in the electric storage. The temperature sensing means is operated by an output from the power storage means, and exhibits electric characteristics according to the temperature of the contact / separation member. The control means applies a high-frequency signal corresponding to the electrical characteristics of the temperature sensing means to the secondary coil. As a result, a high-frequency current is induced in the primary coil, and the temperature of the contact / separation member is determined by the temperature detecting means based on the characteristic.

Subsequently, in the temperature detecting device for the contact / separation member according to the third invention, when a high frequency current is output from the high frequency generating means to the primary coil, the mutual induction between the primary coil and the secondary coil is reduced. A high-frequency current is induced in the secondary coil based on this, and a current flows through the vibrator. The resonance frequency of the vibrator changes according to the temperature of the contact / separation member. The temperature detecting means detects the resonance level of the primary coil, and the resonance frequency is detected by the temperature detecting means to determine the temperature of the contact / separation member.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an electromagnetic cooker 1 provided with a temperature detecting device according to the first invention. The electromagnetic cooker 1 includes a cooker main body 2 (hereinafter, referred to as “main body 2”) and a cooking vessel 6.
(Hereinafter referred to as “container 6”). The cooking table 3 of the main body 2 is formed of a glass-based material. As shown in FIG. 2, a coil 4 is provided at the center of the lower surface, and a heating coil 5 is arranged around the coil 4.
As shown in FIG. 3, the container 6 includes a temperature-sensitive element 8 (for example, a thermistor) whose electric characteristics, for example, electric resistance change according to temperature, inside a protective case 7 at the center of the bottom upper surface.
The coil 9 is accommodated.

FIG. 4 is a circuit diagram showing the electrical connection of the coils 4, 9 and the temperature sensing element 8, etc. In the main body side circuit 10, the current output from the control unit 11 is converted into a high-frequency current by the oscillation unit 12. This high-frequency current is applied to the coil 4. Further, the magnitude of the high-frequency current is detected by the detection unit 13, and the detected value is output to the control unit 11. On the other hand, the coil 9 of the container side circuit 14
And the temperature sensing element 8 constitute a DC closed circuit.

In the electromagnetic cooker 1 having the above configuration, the container 6 is placed on the cooking table 3 such that the main body side coil 4 and the container side coil 9 approach during cooking. When power is supplied to the main body in this state, a high-frequency current flows through the heating coil 5, an eddy current is generated in the container 6, and the heat generation action heats the container 6 and the cooked contents.

In the main body side circuit 10, the current output from the control unit 11 is converted into a high-frequency current by the oscillation unit 12 and applied to the coil 4. As a result, the magnetic flux formed in the main body side coil 4 links with the container side coil 9, a current is induced in the container side coil 9 based on the mutual induction action, and the temperature sensing element 8
Works.

The temperature-sensitive element 8 changes its electrical characteristics, for example, its electrical resistance, according to the temperature of the container 6. That is, in the container-side circuit 14, the impedance changes according to the temperature change of the container 6. Further, the value of the high-frequency current oscillated by the oscillating unit 12 of the main body side circuit 10 changes according to the change in the impedance. Then, the detection unit 1 of the main body side circuit 10
Numeral 3 detects the value of the high-frequency current, and the controller 11 calculates the temperature of the container 6 based on the detection result.

In the above embodiment, the case where the temperature detecting device according to the present invention is applied to an electromagnetic cooker has been described.
The present invention is also applicable to cookers such as fryers, electric rice cookers, and electric pots. Further, the coil 9 is not limited to the container,
In an electric rice cooker, an electric pot or the like, it may be provided on a lid.
That is, the coil 9 may be a member that comes into contact with and separates from the cooking device main body.

FIG. 5 shows an example of application to a flyer. In this flyer 15, the main body 2a has a main body side control circuit 10a having a coil 4a, an oscillating section, a detecting section and a control section (not shown), and a container 6a detachable from the main body 2a.
Has a heater 5a for heating, a protective case 7a containing a temperature-sensitive element 8a and a coil 9a, and the coils 4a and 9a are opposed to each other in the mounted state shown in the drawing, and based on the mutual induction action of the two, the above embodiment is used. In the same manner as described above, the temperature of the container 6a can be detected.

The arrangement of the coils in the temperature detecting device is not limited to the above embodiment. For example, as shown in FIG. 6, a protective case 7b is provided on the lower surface of the container 6b, and the concave portion 3b is formed in the main body 2b. May be provided, and the protective case 7b may be inserted into the recess 3b for positioning. By doing so, the positional relationship between the main body side coil 4b and the container side coil 9b in the cooking state is fixed, the mutual inductance of the two coils 4b, 9b is constant, and the accuracy of temperature detection is improved. Further, the main body side coil 4b is positioned around the recess 3b, and the main body side coil 4b and the container side coil 9b are positioned.
Are arranged concentrically, the leakage magnetic flux is reduced and the temperature detection accuracy is further improved.

Further, depending on the type of cooker, as shown in FIG. 7, the convex portion 3 for accommodating the coil 4c is provided on the main body side 2c.
The protrusion 3c may be provided to face the protective case 7c and the coil 9c of the container 6c. In addition,
8c is a temperature sensing element.

FIG. 8 shows a circuit configuration of the temperature detecting device according to the second invention. In the main body side circuit 20, the current output from the control unit 21 is converted into a high frequency current by the oscillation unit 22, and this high frequency current is The voltage is applied to the coil 23. The current induced in the coil 23 is demodulated by the demodulation unit 24 and output to the control unit 21.

In the container side circuit 25, the coil 26 is connected to a power storage unit 29 (for example, a capacitor) of a control unit 28 via a rectifying unit 27. Further, a temperature sensing element 30 for detecting the temperature of the container is connected to the control unit 28. Further, a modulation unit 31 is connected to the control unit 28, and the control unit 28
Is modulated in accordance with the temperature detected by the temperature sensing element 30 and output to the coil 26.

In the above temperature detecting device, as shown in FIG. 9, when the main body side circuit 20 is set to the oscillation mode, the control section 21 outputs a current (# 1). This current is generated by the oscillator 2
At 2, the current is converted into a high-frequency current and applied to the main body side coil 23. The oscillation of the control section 21 is stopped after a predetermined time (# 2), and the main body side circuit 20 is set to the reception mode (# 3).

On the other hand, as shown in FIG. 10, the container-side circuit 25 receives the high-frequency current induced in the container-side coil 26, rectifies it into DC by the rectifier 27, and stores it in the power storage unit 29 (# 11). ). Further, the control unit 28 applies a current to the temperature sensing element 30 from the power storage unit 29 to detect the container temperature (# 1).
2). Next, when the main body side circuit 20 is set to the reception mode and the reception of the high frequency is stopped (# 13: YES), the modulation unit 31 is operated to modulate the high frequency current applied to the coil 26 according to the container temperature, The temperature data is transmitted to the main body side circuit 20 (# 14). Note that the modulation includes amplitude modulation, frequency modulation, pulse width modulation, and the like.

Returning to FIG. 9, the main body side circuit 20 receives the data transmitted from the container side circuit 25 (# 3). When the reception is completed (# 4: YES), the high-frequency current induced in the main body side coil 23 is demodulated by the demodulation unit 24, and the container temperature is obtained from the demodulated signal (# 5).

As described above, the main body side circuit 20 is switched between the oscillation mode and the reception mode at predetermined time intervals, and the container temperature is intermittently detected. However, if the oscillation frequencies of the main body side circuit 20 and the container side circuit 25 do not match, the output of the main body side circuit 20 is always turned on, and continuous temperature detection becomes possible.

FIG. 11 is a circuit diagram of a temperature detecting device according to the third invention. In this temperature detecting device, a crystal resonator 80 is used as a temperature-sensitive element. Other configurations are the same as those shown in FIG. 4, and the same portions are denoted by the same reference numerals and description thereof will be omitted.

As shown in FIG. 12, the temperature detecting device utilizes the characteristic that the frequency at which the vibration level (resonance level) of the crystal unit 80 becomes maximum changes depending on the environmental temperature or the detected temperature. That is, when the frequency of the high-frequency current induced in the container-side coil 9 is increased, the vibration level of the crystal oscillator 80 gradually increases, and the frequency at which the vibration level reaches the maximum is read, whereby the crystal oscillator 80 is read. This utilizes the property that the ambient temperature can be determined.

More specifically, with reference to FIG. 14, the main body side circuit 10 includes a control unit 1 as shown in FIG.
The high frequency current is applied to the coil 4 from the oscillation unit 12 for a predetermined time according to the output of # 1 (# 21). As described later, the oscillation frequency f _n of the high-frequency current is increased stepwise. When a high-frequency current flows through the main body side coil 4, a current is induced in the coil 9 of the container side circuit 14, and the crystal resonator 80 vibrates. The vibration state at this time is shown in FIG.
On the other hand, the current value I _n of the main coil 9 varies in accordance with the vibration level of the crystal oscillator 80. The main body control unit 11 detects the current value I _n of the body-side coil 4 (# 22), the current value I _n and the frequency is set just before _{f n-1 (f n-} 1 <f n)
It compares the current value I _n-1 in step _{(# 23), I n>} I
_{If n-1} , the oscillation frequency of the oscillation unit 12 is raised by one step (f _n ←
f + Δf) (# 24), _{if In} ≦ I _n−1 , it is determined that the vibration level of the crystal unit has reached the maximum, and the container temperature is obtained from the oscillation frequency f _n or f _n−1 at that time. (# 25).
When the container temperature is determined, the oscillation frequency f _n is returned to the initial state f ₀ and the same processing is repeated (# 26).

A second embodiment according to the third invention will be described with reference to FIG. In this embodiment, as shown in FIG. 13 (b), even when the high-frequency current flowing through the main body side coil 4 is turned off, the oscillation of the crystal oscillator 80 does not completely stop and shows slow attenuation. This utilizes the property that the reception level of the current induced from the container side coil 9 to the main body side coil 4 corresponds to the vibration (resonance) level of the crystal unit.

[0030] Specifically, the body-side circuit 10, first, the control unit 11 is set to the oscillation mode, a high-frequency current having a frequency f _n by the oscillator 12 is applied a predetermined time to the coil 4 in accordance with the output (# 31 ), A high-frequency current is induced in the container side coil 9 to vibrate the crystal oscillator 80. Next, the oscillation of the main body side circuit 10 is turned off to switch to the reception mode (# 3).
2). As a result, the vibration of the crystal unit 80 is
(B) As shown in FIG. Also, the crystal oscillator 8
A current flows through the container-side coil 9 by the damping vibration of 0, and a high-frequency current is induced in the main-body-side coil 4. Subsequently, the main body side control section 11 detects the reception level V _n of the current induced in the main body side coil 4, and detects the reception level V _n and the frequency f _n−1 (f _n−1 <fn) set immediately before. )), The reception level is compared with the reception level V _n−1 (# 33). If V _n > V _n−1 , the oscillation frequency is increased by the oscillation unit 12 (f _n ← f + Δf) (# 3)
4) If V _n ≦ V _n−1 , vibration (resonance) of the crystal unit 80
Judge that the level has reached the maximum and calculate the container temperature (#
35). When the container temperature is determined, the oscillation frequency is returned to the initial state (f _n ← f ₀ ), and the same processing is repeated (# 3).
6).

In the above description, the temperature sensing element is provided on a member such as a pot or a container. However, in an electric rice cooker or an electric pot, the temperature sensing element may be provided on a lid.

[0032]

As is apparent from the above description, in the temperature detecting device for a cooking appliance according to the present invention, the temperature sensing means can be provided directly on the detachable or openable / closable member from the cooking appliance main body. The temperature of the contact / separation member can be directly detected by the temperature sensing means. Therefore, even if the contact / separation member is formed of a material having a large heat capacity, the temperature of the container can be accurately detected.

[Brief description of the drawings]

FIG. 1 is a perspective view of a cooker.

FIG. 2 is a partial cross-sectional view of the temperature detecting device in the cooking device main body.

FIG. 3 is a partial sectional view of a temperature detecting device in a cooking container.

FIG. 4 is a circuit diagram of a temperature detection device.

FIG. 5 is a cross-sectional view showing an application example of a temperature detection device to a flyer.

FIG. 6 is a sectional view of another embodiment of the temperature detecting device.

FIG. 7 is a cross-sectional view of another embodiment of the temperature detecting device.

FIG. 8 is a circuit diagram of a temperature detection device according to a second invention.

FIG. 9 is a control flowchart of a main body side control unit of the temperature detection device according to the second invention.

FIG. 10 is a control flowchart of a container-side control unit of the temperature detection device according to the second invention.

FIG. 11 is a circuit diagram of a temperature detection device according to a third invention.

FIG. 12 is a diagram showing the vibration characteristics of the crystal resonator according to the third invention.

FIG. 13 is a diagram showing an oscillation output on the main body side and an oscillation output on the container side in the temperature detection device according to the third invention.

FIG. 14 is a control flowchart of a main body side control unit of the temperature detection device according to the third invention.

FIG. 15 is another control flowchart of the main body side control unit of the temperature detection device according to the third invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cooking device, 2 ... Cooking device main body, 4 ... Body side coil (primary side coil), 6 ... Cooking container (contact / separation member), 8 ... Temperature sensing element, 9 ... Secondary side coil, 11 ... Control part , 12 ... oscillator,
13: detection unit, 80: crystal oscillator.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI A47J 37/12 301 A47J 37/12 301 G01K 7/00 G01K 7/00 Z 7/36 7/36

Claims (4)

(57) [Claims] An apparatus for detecting a temperature of a cooker, comprising: a cooker main body; and a detachable or openable / closable contact / separation member for the cooker main body, wherein the contact / separation member has an electrical characteristic according to a temperature. A variable temperature sensing means, and a secondary coil forming a series closed circuit together with the temperature sensing means, wherein the cooking device main body has a primary coil, and a mutual connection between the primary coil and the secondary coil. A high-frequency generating means for inducing a current in the secondary coil by an induction action; and a temperature detecting means for determining the temperature of the contact / separation member from the level of the current flowing in the primary coil. Detection device. 2. A temperature detecting device for a cooker comprising: a cooker main body; and a detachable / openable / closable contact / separation member for the cooker main body, wherein the contact / separation member includes a secondary coil; Rectifying means for rectifying the current flowing in the secondary coil, power storage means for storing electric charge flowing through the rectification means, temperature-sensitive means whose electric characteristics change in accordance with temperature and which are operated by an output from the power storage means, A control means for outputting a high-frequency current corresponding to a change in the electrical characteristics of the temperature-sensitive means to the secondary coil; a primary coil; High-frequency generating means for inducing a current in the secondary coil by the mutual induction of the side coils; and temperature detecting means for obtaining the temperature of the contact / separation member from characteristics of the current induced in the primary coil by the mutual induction. It is characterized by having Temperature sensing device of the cooker. 3. A temperature detecting device for a cooking device comprising a cooking device main body and a detachable or openable / closable contacting / separating member for the cooking device main body, wherein the contacting / separating member detects a change in temperature of the contacting / separating member. A vibrator whose resonance frequency changes in response to the vibrator and a secondary coil forming a series closed circuit together with the vibrator; a primary coil; A cooking device comprising: a high-frequency generating means for inducing a current in the secondary coil by a mutual induction action of the coils; and a temperature detecting means for obtaining a temperature of the contact / separation member from an oscillation frequency of the high-frequency generating means. Temperature detector. 4. The cooking device according to claim 1, wherein the primary coil and the secondary coil are arranged such that one of them is located around the other in a cooking state. Cooking device temperature detector.