CN115789749A - surface heating tools - Google Patents

Abstract

The purpose is to detect the deterioration of the wire heater and stop the energization. The planar heating tool (100) of the present invention has: a wire heater (30), wired in the heating part (10), having a heater wire (32), a temperature detection wire (34) and an intermediate layer (33); And the control part (40) controls the temperature of the heating part (10) by alternately switching the energization and stoppage of energization to the heater wire (32) based on the temperature information detected by the temperature detection wire (34). The control unit (40) continues to stop the energization of the heater wire (32) based on information on at least one of energization and cessation of the energization to the heater wire (32).

Description

surface heating tools

technical field

The present invention relates to planar heating tools.

Background technique

Conventionally, there is known a surface heating tool using a single-wire type wire heater in which a heater wire and a temperature detection wire are integrally configured (see Patent Document 1). Such a surface heating tool is controlled so that the temperature desired by the user is achieved by heating the heater wire based on the temperature information detected by the temperature detection wire.

prior art literature

patent documents

Patent Document 1: Japanese Patent Application Laid-Open No. 6-5175

Contents of the invention

The problem to be solved by the invention

However, if an object is placed on the planar heating tool for a long time, the heat dissipation performance of the position will be impaired, and the high temperature state will continue due to partial heat retention. If such a high-temperature state continues, the intermediate layer between the heater wire and the temperature detection wire gradually deteriorates, and the heater wire and the temperature detection wire may be short-circuited. Surface heating tools usually have a thermal fuse as a safety device, and the thermal fuse is blown when the heater line and the temperature detection line are short-circuited. However, depending on the degree of deterioration of the intermediate layer, the thermal fuse is not blown, or it may be earlier than expected. ground was fused.

The purpose of the present invention is to detect the deterioration of the wire heater and stop the energization.

means to solve problems

The present invention is a planar heating tool, comprising: a wire heater, wired in a heating part, having a heater wire, a temperature detection wire, and an intermediate layer between the heater wire and the temperature detection wire; and a control mechanism, based on the temperature information detected by the above-mentioned temperature detection line, alternately switch the energization and energization stop of the above-mentioned heater line, and control the temperature of the above-mentioned heating part; it is characterized in that the above-mentioned control mechanism is based on Information on at least one of the energization and energization stop, continues the energization stop of the heater wire.

Invention effect

According to the present invention, deterioration of the wire heater can be detected and energization can be stopped.

Description of drawings

Fig. 1 is a diagram schematically showing the structure of a planar heating tool.

FIG. 2 is a diagram showing an example of a schematic configuration of a wire heater.

Fig. 3 is a diagram showing an example of an internal structure of a planar heating tool.

FIG. 4 is a graph showing an example of a change in voltage of a temperature detection line, and the like.

FIG. 5 is a graph showing an example of changes in temperature of the wire heater and the like.

FIG. 6 is a graph for explaining leakage current.

FIG. 7 is a diagram showing an example of a change in voltage of a temperature detection line when a leakage current increases.

FIG. 8 is a diagram showing an example of a change in voltage of a temperature detection line and the like in a case where there is a leakage current.

Fig. 9 is a flowchart showing an example of processing in the first embodiment.

Fig. 10 is a flowchart showing an example of processing in the second embodiment.

Fig. 11 is a flowchart showing an example of processing in the third embodiment.

FIG. 12 is a diagram showing an example of the configuration of an energization control unit of the fourth embodiment.

FIG. 13 is a diagram for explaining processing of an energization control unit.

Fig. 14 is a flowchart showing an example of processing in the fourth embodiment.

FIG. 15 is a diagram showing an example of the configuration of an energization control unit in the fifth embodiment.

Fig. 16 is a flowchart showing an example of processing in the fifth embodiment.

Label description

100: surface heating tool; 10: heating part; 20: controller; 21: temperature setting part; 22: reporting part; 30: line heater; 32: heater line; 33: middle layer; 34: temperature detection line; 38: smoothing circuit; 40: control unit; 50: energization control unit; 60: temperature control unit.

Detailed ways

Hereinafter, the surface heating tool according to this embodiment will be described with reference to the drawings. In this embodiment, it is assumed that it is applied to an electric blanket as a planar heating tool.

FIG. 1 is a diagram schematically showing an example of the structure of a planar heating tool 100 . The planar heating tool 100 starts driving by receiving, for example, AC 100V power.

The planar heating tool 100 includes a heating unit 10 , a controller 20 , and a wire heater 30 .

The heating unit 10 is a planar portion that a user rides on to be heated. The heating unit 10 is, for example, rectangular when viewed from above, and has a large area along the horizontal direction. The heating unit 10 is constructed by laminating a surface layer, a cushion layer, a heat insulating layer, and the like in this order from the top. The surface layer is a portion that comes into contact with the user, and for example, felt, polyvinyl chloride (PVC), or the like can be used. The underlayment disperses the force acting on the heating unit 10 when the user rides on the heating unit 10 to impart elasticity to the user, or to keep heat from the heat generated by the wire heater 30 . As a cushion layer, polyurethane etc. can be used, for example. In addition, the heat insulating layer performs heat insulation so that the heat generated by the wire heater 30 is not dissipated to the ground. As a heat insulating layer, felt etc. can be used, for example.

The controller 20 controls the temperature of the heating unit 10 by alternately switching between energization and de-energization of heater wires 32 to be described later for the wire heaters 30 . The controller 20 is arranged at a location exposed to the heating unit 10 . The controller 20 is electrically connected to a temperature setting unit 21 for the user to set the temperature of the heating unit 10 to a desired temperature, and a reporting unit 22 for notifying the user of the driving state of the surface heating tool 100 . The temperature setting unit 21 is, for example, a switch for setting a desired temperature level (for example, Lv1 to Lv5 ) by sliding a knob by the user, and inputs a voltage corresponding to the slid position to the controller 20 . Here, the temperature level Lv1 corresponds to "weak" in which the temperature of the heating part 10 becomes low, and the temperature level Lv5 corresponds to "strong" in which the temperature of the heating part 10 becomes high. The reporting unit 22 is, for example, a light emitting unit such as an LED, and by changing the time of turning on and the time of turning off, it notifies the user of the driving state of the surface heating tool 100 at the present time.

The wire heater 30 generates heat by converting electric power into heat by being energized. The wire heater 30 is wired into the heating part 10 . Specifically, the wire heater 30 is wired along the surface direction between the mat layer and the heat insulating layer in the heating unit 10 . The wire heater 30 heats the entire heating part 10 by being wired in a meandering manner or in a helical shape over the entire surface of the heating part 10 . In addition, it is also possible to preliminarily produce a unit in which the wire heater 30 is sandwiched from top and bottom by members such as sheet-like non-woven fabrics, and to arrange the wire heater 30 by laminating the produced unit between the mat layer and the heat insulating layer. Line to the heating department 10.

FIG. 2 is a diagram showing an example of a schematic configuration of the wire heater 30 .

A so-called single-wire type wire heater is used for the wire heater 30 . Specifically, the wire heater 30 has a winding core 31 , a heater wire 32 , an intermediate layer 33 , a temperature detection wire 34 , and a sheath layer 35 . The winding core 31 is made of polyester resin, for example, and the heater wire 32 is arranged on the outer periphery. The heater wire 32 is, for example, a conductor such as copper alloy, and is wound helically and arranged on the outer periphery of the winding core 31 . The intermediate layer 33 is a polymer layer such as nylon resin, and the temperature detection line 34 is arranged on the outer periphery. The temperature detection wire 34 is a conductor such as nickel, and is wound in a helical shape and arranged on the outer periphery of the intermediate layer 33 . The temperature detection line 34 has a characteristic that the resistance value increases as the temperature increases. The skin layer 35 is, for example, polyvinyl chloride or the like, and is disposed on the outermost periphery. In addition, the wire heater 30 is not limited to the above-mentioned structure and material, for example, the heater wire 32 and the temperature detection wire 34 are arranged oppositely, or another layer is added, and the structure and material can be appropriately changed.

FIG. 3 is a diagram showing an example of the internal structure of the planar heating tool 100 .

As shown in FIG. 3 , the surface heating tool 100 includes a control unit 40 , various elements, and circuits in addition to the above-mentioned wire heater 30 . The control unit 40 and various elements and circuits are arranged in the above-mentioned controller 20 .

The resistor H1 in the wire heater 30 shown in FIG. 3 is the heater wire 32, and one end of the heater wire 32 in the longitudinal direction is connected to the contact h1, and the other end is connected to the contact h2. In addition, the resistor S1 is the temperature detection line 34, and one end of the temperature detection line 34 in the longitudinal direction is connected to the contact s1, and the other end is connected to the contact s2. In addition, the heater wire 32 and the temperature detection wire 34 are insulated by the intermediate layer 33 .

Moreover, the power supply of AC100V for energizing the heater wire 32 is supplied to the contact v1 and the contact v2. Between the contact v1 and the contact v2, the heater wire 32 (resistance H1), the switch SW, and the thermal fuse TF1 are connected in series. The heating unit 10 is heated by energizing the heater wire 32 to generate heat. The heater wire 32 is energized when the switch SW is on, and the heater wire 32 is stopped when it is off. The switch SW can be switched on and off by a relay RL or an energization control unit 50 described later. The thermal fuse TF1 is heated by a resistor TF1-R integrally formed with the thermal fuse TF1, and is melted when the temperature reaches a predetermined temperature or higher. When the thermal fuse TF1 is blown, even if the switch SW is turned on, the energization to the heater wire 32 is cut off. Therefore, until the thermal fuse TF1 is replaced with a new one, the heater wire 32 does not generate heat and cannot heat the heating unit 10 .

In addition, a control power supply of, for example, DC5V for temperature control is supplied from the contact point u1 to the contact point u2. Here, the control power supply is supplied by converting AC100V with a voltage conversion circuit not shown. Between the contact point u1 and the contact point u2, a resistor R1, a variable resistor VR1, a temperature detection line 34 (resistor S1), and a resistor R2 are connected in series. The temperature detection line 34 changes the resistance S1 according to the temperature, and inputs a DC voltage corresponding to the temperature to the control unit 40 . Resistors R1 and R2 are resistors for dividing voltage so that the voltage input to control unit 40 becomes an appropriate value, and variable resistor VR1 is a resistor for adjusting according to the type (model) of the surface heating tool. In addition, the smoothing circuit 38 composed of the resistor R3 and the capacitor C1 is a circuit for smoothing the voltage input to the control unit 40 .

In addition, anodes of diodes D1 and D2 are respectively connected to both ends of temperature detection line 34, and cathodes of diodes D1 and D2 are connected together to one end of resistor TF1-R. In addition, the anode of the diode D3 is connected to the other end of the resistor TF1-R, and the cathode of the diode D3 is connected between the thermal fuse TF1 and the switch SW.

The control unit 40 has an energization control unit 50 and a temperature control unit 60 .

The energization control unit 50 controls not to energize the heater wire 32 of the wire heater 30 when deterioration of the wire heater 30 is detected. Note that the processing performed by the energization control unit 50 will be described later.

The temperature control unit 60 controls the temperature of the heating unit 10 by alternately switching between energization and de-energization of the heater wire 32 based on temperature information detected by the temperature detection line 34 . The temperature control unit 60 has an AD converter 61 , an AD converter 62 , a meter 63 , a selector 64 , an upper limit comparator 65 a, a lower limit comparator 65 b, and a relay switching unit 66 .

The AD converter 61 converts the voltage corresponding to the temperature detected by the temperature detection line 34 into a digital signal, and outputs it to the upper limit comparator 65a and the lower limit comparator 65b, respectively. The AD converter 62 converts the voltage corresponding to the temperature level set by the temperature setting unit 21 into a digital signal, and outputs it to the selector 64 . The table 63 holds information of the upper limit threshold value and the lower limit threshold value for each temperature level (Lv1 to Lv5 ) set by the temperature setting unit 21 . Here, for example, if the upper limit threshold of temperature level Lv1 is set as Vrmax1, the lower limit threshold of temperature level Lv1 is Vrmin1, the upper limit threshold of temperature level Lv5 is Vrmax5, and the lower limit threshold of temperature level Lv5 is Vrmin5, then Vrmax1>Vrmin1, The relationship of Vrmax5>Vrmin5, Vrmax5>Vrmax1, Vrmin5>Vrmin1.

The selector 64 extracts an upper limit threshold and a lower limit threshold corresponding to the temperature level set by the temperature setting unit 21, and outputs them to the upper limit comparator 65a and the lower limit comparator 65b, respectively.

The upper limit comparator 65 a compares the voltage value input from the detection line input terminal (hereinafter referred to as detection line input) based on the output of the temperature detection line 34 with the upper limit threshold, and outputs the comparison result to the relay switching unit 66 . The lower limit comparator 65b compares the voltage value input from the detection line input with the lower limit threshold, and outputs the comparison result to the relay switching unit 66 .

Relay switching unit 66 switches relay RL on and off based on comparison results from upper limit comparator 65a and lower limit comparator 65b. Specifically, relay switching unit 66 turns on relay RL when the voltage value of the detection line input is the lower limit threshold or is smaller than the lower limit threshold. Furthermore, relay switching unit 66 turns on relay RL when the voltage value of the detection line input reaches the lower limit threshold and then moves within a range between the lower limit threshold and the upper limit threshold. On the other hand, relay switching unit 66 turns off relay RL when the voltage value of the detection line input is the upper limit threshold or is larger than the upper limit threshold. In addition, the relay switching unit 66 turns off the relay RL when the voltage value of the detection line input reaches the upper threshold and then moves to a range between the lower threshold and the upper threshold.

When the relay RL is turned on, the switch SW is turned on, and the heater wire 32 is energized. On the other hand, when the relay RL is turned off, the switch SW is turned off, and energization to the heater wire 32 is stopped.

Here, a change in the voltage of the temperature detection line 34 , a change in the energization state of the heater line 32 , and a change in the temperature of the line heater 30 corresponding to the above-mentioned operation by the temperature control unit 60 will be described with reference to FIG. 4 . In addition, FIG. 4 is a diagram showing an operation in a normal state where there is no leakage current, and in this case, the voltage of the temperature detection line 34 matches the voltage input to the detection line.

4( a ) is a diagram showing changes in the voltage of the temperature detection line 34 , FIG. 4( b ) is a diagram showing changes in the energized state of the heater wire 32 , and FIG. 4( c ) is a diagram showing the temperature of the wire heater 30. change graph. Note that the voltage of the temperature detection line 34 here is a voltage value smoothed by the smoothing circuit 38 and output to the control unit 40 .

The voltage value Va1 shown in FIG. 4( a ) is the voltage value of the temperature detection line 34 when the temperature of the wire heater 30 is rising. Here, since the voltage value moves to a range between the lower limit threshold and the upper limit threshold after the voltage value reaches the lower limit threshold, the relay RL is turned on, and the heater wire 32 is energized as shown in FIG. 4(b) (open state ). Therefore, as shown in FIG. 4( c ), the temperature of the wire heater 30 also continues to rise. In addition, the time of the ON state shown in FIG.4(b) is represented by HHs. Then, when the voltage value reaches the upper limit threshold value, the relay RL is turned off, and the energization to the heater wire 32 is stopped (closed state). In addition, the temperature of the wire heater 30 is lowered from Toff by stopping the energization of the heater wire 32 .

The voltage value Vb1 shown in FIG. 4( a ) is the voltage value of the temperature detection line 34 when the temperature of the wire heater 30 drops by stopping the energization to the heater wire 32 . Here, since the voltage value moves to a range between the lower threshold and the upper threshold after the voltage value reaches the upper threshold, the relay RL is closed, and as shown in FIG. Disabled). Therefore, as shown in FIG. 4( c ), the temperature of the wire heater 30 also continues to drop. In addition, the time of the closed state shown in FIG.4(b) is represented by HLs. Then, when the voltage value reaches the lower limit threshold value, the relay RL is turned on, and the heater wire 32 is energized (open state). In addition, the temperature of the wire heater 30 rises from Ton by energizing the heater wire 32 .

In this way, as shown in FIG. 4( a), the voltage value passing through the temperature detection line 34 repeatedly rises and falls between the lower limit threshold and the upper limit threshold, and the energization and energization of the heater line 32 as shown in FIG. 4( b) Stopping and switching alternately, as shown in FIG. 4( c ), the temperature of the wire heater 30 repeatedly rises and falls.

Also, when the temperature level set by the temperature setting unit 21 becomes higher, the lower limit threshold and the upper limit threshold compared by the upper limit comparator 65a and the lower limit comparator 65b become larger, respectively. Therefore, the higher the temperature level set by the temperature setting section 21 is, the higher the temperature of the wire heater 30 is repeatedly raised and lowered.

FIG. 5 is a graph showing an example of changes in the temperature of the wire heater 30 and the surface temperature of the heating unit 10 after power is supplied to the planar heating tool 100 . In addition, the cycle of the rise and fall of the temperature of the wire heater 30 shown in FIG. 5 is the same as the cycle of the rise and fall of the temperature of the wire heater 30 shown in FIG. 4 (c), and FIG. A graph in which time is set longer than the time on the horizontal axis of FIG. 4( c ). The unit of the horizontal axis shown in FIG. 5 is hour [h(hour)].

As shown in FIG. 5 , as the temperature of the wire heater 30 repeatedly rises and falls, the surface temperature of the heating unit 10 also repeatedly rises and falls at approximately the same cycle. At this time, the surface temperature of the heating unit 10 repeats rising and falling at a temperature corresponding to the temperature level set by the temperature setting unit 21 similarly to the temperature of the wire heater 30 . In addition, the temperature range between the upper limit and the lower limit of the surface temperature of the heating unit 10 is smaller than the temperature range between the upper limit and the lower limit of the temperature of the wire heater 30, and the temperature change is not noticed by the user.

In this way, the temperature control unit 60 controls the temperature of the heating unit 10 by alternately switching between energization and de-energization of the heater wire 32 based on the temperature information detected by the temperature detection line 34 .

Next, a method of detecting deterioration of the wire heater 30 will be described. FIG. 6 is a diagram showing a state where leakage current has occurred due to deterioration of the wire heater 30 . Specifically, FIG. 6( a ) is a diagram showing leakage current when the AC power supply is a positive half-wave, and FIG. 6( b ) is a diagram showing leakage current when the AC power supply is a negative half-wave.

The higher the temperature around the intermediate layer 33 of the wire heater 30 is, the more the deterioration progresses, and the more the deterioration progresses, the more the insulation resistance decreases. The insulation resistance of the intermediate layer 33 decreases, and the alternating current energized to the heater wire 32 leaks to the temperature detection wire 34 via the intermediate layer 33 .

When the AC power supply is a positive half wave as shown in FIG. 6( a ), the contact v1 is positive and the contact v2 is negative. The leakage current leaked from the heater wire 32 to the temperature detection wire 34 via the intermediate layer 33 flows to the smoothing circuit 38 via the contact s1 and the branch point A, and flows to the control GND via the contact s2 . Also, when the AC power supply is a positive half-wave, since the voltage on the side of diodes D1 and D2 is higher than that of contacts s1 and s2 , leakage current does not flow from contacts s1 and s2 to diodes D1 and D2 . When the leakage current flows into the smoothing circuit 38 via the contact point s1 and the branch point A, a voltage corresponding to the leakage current is added to the voltage detected by the temperature detection line 34 and input to the control unit 40 .

When the AC power supply is a negative half-wave as shown in FIG. 6( b ), the contact v1 is negative and the contact v2 is positive. The leakage current leaking from the heater wire 32 to the temperature detection wire 34 via the intermediate layer 33 flows from the diodes D1 and D2 to the resistor TF1 -R and the diode D3 via the contact s1 and the contact s2 . In addition, when the AC power supply is a negative half-wave, since the voltage on the side of the branch point A is higher than that on the side of the diodes D1 and D2 , leakage current does not flow to the side of the branch point A. In addition, if the deterioration of the intermediate layer 33 progresses further, the heater line 32 and the temperature detection line 34 are short-circuited, and the leakage current further flows into the resistor TF1-R, and the resistor TF1-R generates heat to become high temperature, and the temperature fuse TF1 fuse. When the thermal fuse TF1 is blown, even if the switch SW is turned on, the energization to the heater wire 32 is cut off, and functions as a final protection circuit.

Here, focusing on the voltage at the branch point A shown in FIGS. 6( a ) and 6 ( b ), at the branch point A, a voltage corresponding to the leakage current occurs only in the positive half-wave of the AC power supply. On the other hand, if attention is paid to the voltage input to the control unit 40 of the circuit shown in FIG. 6(a) and FIG. The smoothing circuit 38 smoothes.

FIG. 7 is a graph showing changes in voltage detected by leakage current. Here, the description will be given assuming that the AC power supply is 60 Hz. As shown in FIG. 7 , when the leakage current is low, a voltage dv corresponding to the leakage current occurs at the branch point A every 1/60 second, that is, every half-wave of AC. The voltage dv corresponding to this leakage current is smoothed by the smoothing circuit 38 to become a voltage adv (see "smoothed value" shown in FIG. 7 ). As a result, a voltage obtained by adding a voltage adv corresponding to the leakage current to the voltage detected by the temperature detection line 34 is input to the control unit 40 .

Also, when the leakage current increases and becomes high, at the branch point A, a voltage dv+ higher than the voltage dv is generated every 1/60 second corresponding to the leakage current (see the dotted line shown in FIG. 7 ). The voltage dv+ corresponding to this leakage current is smoothed by the smoothing circuit 38 to become a voltage adv+ higher than the voltage adv. As a result, the voltage obtained by adding the voltage adv+ corresponding to the leakage current to the voltage detected by the temperature detection line 34 is input to the control unit 40 .

In this way, when a voltage added corresponding to the leakage current is input to the control unit 40, the voltage of the temperature detection line 34 is lower than that of a case where only the voltage detected by the temperature detection line 34 is input to the control unit 40 without current leakage. Changes etc. become different dynamics. Specifically, referring to FIG. 8 , the change in the voltage of the temperature detection line 34 and the energization of the heater line 32 corresponding to the operation of the temperature control unit 60 when a voltage applied corresponding to the leakage current is input to the control unit 40 will be described. Changes in the state, changes in the temperature of the wire heater 30 .

Fig. 8 (a) is a figure showing the change of the voltage of the temperature detection line 34, and the change of the voltage of the temperature detection line 34 under the situation of leakage current is represented by a solid line, and the change of the voltage of the temperature detection line 34 under the situation of no leakage current The variation of the voltage at 34 is indicated by a dotted line. In addition, the change of the voltage of the temperature detection line 34 when there is no leakage current is the same as the change of the solid line of FIG.4(a). FIG. 8( b ) is a diagram showing changes in the energized state of the heater wire 32 . The change in the energized state when there is a leakage current is shown by a solid line, and the change in the energized state when there is no leakage current is shown by a dotted line. express. In addition, the change of the energized state when there is no leakage current is the same as the change of the solid line in FIG. 4( b ). Fig. 8(c) is a diagram showing the change of the temperature of the wire heater 30. The change of the temperature of the wire heater 30 under the condition of leakage current is represented by a solid line, and the change of the temperature of the wire heater 30 under the condition of no leakage current is shown by a solid line. The change in temperature of 30 is indicated by the dashed line. In addition, the change in the temperature of the wire heater 30 when there is no leakage current is the same as the change in the solid line in FIG. 4( c ).

The voltage value Va2 shown in FIG. 8( a ) is the voltage value of the temperature detection line 34 when the temperature of the wire heater 30 rises. A voltage Δv (offset amount Δv) is added to the voltage value Va2 compared to the voltage value Va1 in the case of no leakage current. The voltage Δv corresponds to the voltage adv or the voltage adv+ shown in FIG. 7 . Here, as shown in FIG. 8( b ), the heater wire 32 is energized (open state), and the temperature of the wire heater 30 continues to rise as shown in FIG. 8( c ). Then, when the voltage value reaches the upper limit threshold quickly in accordance with the applied voltage Δv, the relay RL is turned off, and the heater wire 32 is stopped from being energized (closed state). Therefore, as shown in FIG. 8( b ), the time HH of the on state is corresponding to the voltage value reaching the upper limit threshold sooner, and the heater line 32 is stopped from being energized faster, so compared with the on state without leakage current, The time HHs becomes shorter. In addition, as shown in FIG. 8( c ), since the temperature of the wire heater 30 stops energizing the heater wire 32 quickly, the temperature of the wire heater 30 reaches the temperature Toff faster than in the case of no leakage current. began to descend. In addition, as shown in FIG. 8(a), if the voltage value reaches the upper threshold value, by stopping the energization of the heater wire 32, there is no leakage current itself, so the addition of the voltage Δv amount disappears immediately, returning to no leakage. The voltage value of the temperature detection line 34 (the voltage value on the dotted line shown in FIG. 8( a )) in the case of a current gradually decreases.

The voltage value Vb2 shown in FIG. 8( a ) is the voltage value of the temperature detection line 34 when the temperature of the wire heater 30 drops by stopping the energization to the heater wire 32 . Here, the relay RL is closed, and is a state (closed state) in which energization to the heater wire 32 shown in FIG. 8( b ) is stopped. Therefore, as shown in FIG. 8( c ), the temperature of the wire heater 30 also continues to drop. Then, when the voltage value disappears according to the addition of the voltage Δv and quickly reaches the lower limit threshold value, the relay RL is turned on, and the heater wire 32 is energized (open state). Therefore, as shown in FIG. 8( b ), the time HL of the off state corresponds to the voltage value reaching the lower limit threshold sooner and the heater wire 32 is energized faster, so the time HL of the off state is compared with that in the case of no leakage current. The time HLs become shorter. In addition, as shown in FIG. 8( c ), the temperature of the wire heater 30 starts to rise sooner than in the case of no leakage current due to faster energization of the heater wire 32 .

In the same way, the voltage value passing through the temperature detection line 34 is affected by the addition of the voltage Δv, or the addition of the voltage Δv disappears immediately, and the time HH of the ON state when the heater wire 32 is energized and the time HH of the OFF state when the energization is stopped. HL is respectively shorter than the case of no leakage current, so the cycle of energization and energization stop to the heater wire 32 is shortened. In addition, the cycle of temperature rise and fall of the wire heater 30 is also shortened, and the temperature (average temperature) of the wire heater 30 falls because the temperature Toff in the case of no leakage current is not reached.

In addition, since the voltage Δv increases as the leakage current increases, the cycle of energization and stoppage of energization to the heater wire 32 becomes shorter as the leakage current increases. Also, as the leakage current increases, the period during which the temperature of the wire heater 30 rises and falls becomes shorter, and the temperature (average temperature) of the wire heater 30 decreases.

The energization control unit 50 of this embodiment detects the deterioration of the wire heater 30 before the thermal fuse TF1 is blown based on the above-mentioned various changes caused by the leakage current, stops energization to the heater wire 32 , and stops continuation of energization. Hereinafter, specific processing performed by the energization control unit 50 will be described with reference to a flowchart.

(first embodiment)

In the first embodiment, the energization control unit 50 continues to energize the heater wire 32 based on the information on the energization and cessation of the energization to the heater wire 32 , specifically, based on the cycle of energization and cessation of the heater wire 32 . stop.

FIG. 9 is a flowchart showing an example of processing performed by the energization control unit 50 in the first embodiment. In addition, in the following flowcharts including FIG. 9 , it is realized by the energization control unit 50 executing a program stored in a memory in the energization control unit 50 .

In S10, the energization control part 50 acquires the time HH of the ON state which energized the heater wire 32 (refer FIG.8(b)). The energization control unit 50 acquires the time HH of the ON state when the heater wire 32 is energized by measuring the time when the relay switching unit 66 outputs an ON signal to the relay RL. However, the energization control unit 50 may acquire the ON state time HH by measuring the ON time of the relay RL or the ON time of the switch SW.

In S11, the energization control part 50 acquires the time HL of the OFF state in which energization to the heater wire 32 was stopped (refer FIG.8(b)). The energization control unit 50 acquires the off-state time HL when the energization to the heater wire 32 is stopped by measuring the time when the relay switching unit 66 outputs an off signal to the relay RL. However, the energization control unit 50 may acquire the off-state time HL by measuring the time when the relay RL is turned off or the time when the switch SW is turned off.

In S12, the energization control unit 50 acquires the cycle of energization and energization stop. The energization control unit 50 acquires the period of energization and energization stop by adding the time HH of the ON state and the time HL of the OFF state. As described above, as the leakage current increases, the cycle of energization and stoppage of energization to the heater wire 32 becomes shorter.

In S13 , the energization control unit 50 calculates a difference between the acquired energization and energization stop periods and the energization and energization stop periods when there is no leakage current. In addition, the cycle of energization and energization stop when there is no leakage current corresponds to the time of adding the time HHs of the on state and the time HLs of the off state shown in FIG. in memory. In addition, the energization control part 50 may repeat S10-S13 several times, and may calculate the average value of a difference.

In S14, the energization control unit 50 determines whether or not the period difference is greater than or equal to a predetermined value (threshold value Ta). If the difference is greater than the predetermined value, it proceeds to S15, and if it is not greater than the predetermined value, it returns to S10. The predetermined value is stored in advance in a memory in the energization control unit 50 , and is constant regardless of the temperature level set by the temperature setting unit 21 . In addition, the predetermined value is set to a value smaller than the difference between the energization and energization stop cycle when the thermal fuse TF1 is blown (before) and the energization cycle and the energization stop cycle when there is no leakage current. In addition, the cycle difference may be an average value calculated by repeating S10 to S13 a plurality of times.

In S15 , the energization control unit 50 determines that the wire heater 30 has deteriorated, and stops energization to the heater wire 32 regardless of the temperature information detected by the temperature detection line 34 , and continues to stop energization. Specifically, the energization control unit 50 continues to stop the energization of the heater wire 32 by turning off the relay RL or the switch SW via a safety circuit not shown. The process of stopping energization by the energization control unit 50 takes priority over the process of temperature control by the temperature control unit 60 . In addition, the energization control unit 50 notifies the user that the continuation of energization is stopped due to the deterioration of the wire heater 30 by changing the time when the reporting unit 22 is turned on and the time when it is turned off.

Thus, according to the present embodiment, it is possible to detect deterioration of the wire heater 30 early before the thermal fuse TF1 is blown by continuing to stop the energization of the heater wire 32 based on the cycle of energization and energization stop. In addition, since the cycle of energization and energization stop is longer than the cycle of the waveform of the AC power supply, it is not necessary to measure the cycle with high accuracy, and thus the deterioration of the wire heater 30 can be detected at low cost.

In addition, in the first embodiment, the case of using the cycle of energization and energization stop was described, but the time HH of the ON state when the heater wire 32 is energized and the ON state when there is no leakage current may be used. When the difference in time HHs is equal to or greater than a predetermined value (threshold value Tb), the continuation of energization to the heater wire 32 is stopped. In addition, when the difference between the off-state time HL when the heater wire 32 is not energized and the off-state time HLs when there is no leakage current is greater than or equal to a predetermined value (threshold value Tc), the heater wire 32 may be Continue to power off.

In addition, the ON state time HH in which the heater wire 32 is energized may be compared with a predetermined time (threshold value Td), and the energization to the heater wire 32 may be stopped when the predetermined time is less than the predetermined time. In addition, the off-state time HL in which the heater wire 32 is not energized may be compared with a predetermined time (threshold Te), and the energization of the heater wire 32 may be stopped if the predetermined time is less than the predetermined time. In addition, the measured cycle of energization and energization stop may be compared with a predetermined cycle (threshold value Tf), and when the cycle is equal to or less than the predetermined cycle, energization and stop of heater wire 32 may be continued.

(second embodiment)

In the second embodiment, the energization control unit 50 continues the energization of the heater wire 32 based on the information on the energization and energization stop of the heater wire 32 , specifically, the number of energization and energization stops of the heater wire 32 stop. FIG. 10 is a flowchart showing an example of processing performed by the energization control unit 50 of the second embodiment.

In S20 , the energization control unit 50 counts the number of times of energization and stop of energization to the heater wire 32 , and adds it to the first counter. The energization control unit 50 adds "1" to the first counter when the energization is applied, and then adds "1" to the first counter when the energization is stopped. The energization control unit 50 counts the number of times the relay RL is turned on and off, or the number of times the switch SW is turned on and off, thereby counting the number of times energized and stopped. As the leak current increases, the period of energization and stop of energization to the heater wire 32 becomes shorter as described above. Therefore, as the leak current increases, the number of times of energization and stop of energization within a certain period of time increases.

In S21 , the energization control unit 50 determines whether or not the number of times counted (the first counter) during a certain period of time has become more than or equal to a predetermined number of times (threshold value N, for example, 10 times). If it is more than the predetermined number of times, "1" is added to the second counter, and the process proceeds to S22. On the other hand, if it is not more than the predetermined number of times, it returns to S20, and the count of the number of times of energization and energization stop is continued. The threshold value N is stored in advance in a memory in the energization control unit 50 , and is constant regardless of the temperature level set by the temperature setting unit 21 . In addition, the threshold value N is set to a number smaller than the number of times that the heater wire 32 is energized and energized when the thermal fuse is blown.

In S22 , the energization control unit 50 determines whether or not the counted number of times (first counter) is equal to or greater than a predetermined number of times (threshold value M, for example, 3 times) continuously for a certain period of time. That is, it is determined whether the second counter is continuously added up to a predetermined number of times (threshold value M, for example, 3 times). When the predetermined number of times has been continued, the process proceeds to S23. On the other hand, if there is no continuous predetermined number of times, return to S20, after resetting the counted number of times (first counter, second counter), counting of the number of times of energization and energization stop is continued.

In S23 , the energization control unit 50 determines that the wire heater 30 is degraded, and stops energization to the heater wire 32 regardless of the temperature information detected by the temperature detection wire 34 , and continues to stop energization. This processing is the same processing as S15 described above.

Thus, according to the present embodiment, by continuing to stop the energization of the heater wire 32 based on the number of times of energization and energization stop, deterioration of the wire heater 30 can be detected early before the thermal fuse TF1 is blown.

In addition, in the second embodiment, the case of counting the number of energized and energized stops has been described, but it is also possible to count only the number of energized times and determine whether or not the counted number of times has reached the specified number of times during a certain period of time. (threshold value N/2, such as 5 times) or more, it is also possible to only count the number of times the power is stopped, and determine whether the number of times counted during a certain period of time has become more than a predetermined number of times (threshold value N/2, such as 5 times) . In addition, when the counted number of times reaches the predetermined number of times before a certain time has elapsed, the counted number of times may be reset without waiting for a certain time to elapse, and the counting may be powered on after the next certain time counting is started. and the number of power-off times. In this way, the deterioration of the wire heater 30 can be detected earlier by starting the counting of the next predetermined time without waiting for the elapse of the predetermined time.

(third embodiment)

In the third embodiment, the energization control unit 50 continues to stop the energization of the heater wire 32 based on the information on the temperature of the wire heater 30 , specifically, based on the average temperature of the wire heater 30 .

FIG. 11 is a flowchart showing an example of processing performed by the energization control unit 50 of the third embodiment. In the third embodiment, the surface heating tool 100 has a temperature sensor for measuring the temperature of the wire heater 30 . The temperature sensor is preferably capable of measuring multiple points of the line heater 30 , and for example, a film-shaped multi-point sensor attached to the line heater 30 separately from the line heater 30 may be used. Information on the temperature measured by the temperature sensor is input to the energization control unit 50 .

In S30, the energization control part 50 always acquires the temperature information of the multiple points of the wire heater 30 from a temperature sensor for a predetermined period of time. The energization control unit 50 stores the acquired temperature information of the wire heater 30 .

In S31, the energization control part 50 calculates the average temperature of the wire heater 30 from the acquired temperature information of multiple points. As described above, the average temperature of the wire heater 30 decreases as the leakage current increases.

In S32 , the energization control unit 50 calculates the difference between the calculated average temperature of the wire heater 30 and the average temperature of the wire heater 30 when there is no leakage current. In addition, the average temperature of the wire heater 30 when there is no leakage current is a temperature corresponding to the temperature level set by the temperature setting unit 21 , and is stored in a memory in the energization control unit 50 in advance. In addition, the energization control part 50 may repeat S30-S32 several times, and may calculate the average value of a difference.

In S33 , the energization control unit 50 determines whether the temperature difference is greater than or equal to a predetermined value (threshold value Tg). The predetermined value is stored in advance in a memory in the energization control unit 50 , and is constant regardless of the temperature level set by the temperature setting unit 21 . In addition, the predetermined value is set to a value smaller than the difference between the average temperature of the wire heater 30 when the thermal fuse TF1 is blown and the average temperature of the wire heater 30 when there is no leakage current. In addition, the temperature difference may be an average value calculated by repeating S30 to S32 a plurality of times.

In S34 , the energization control unit 50 determines that the wire heater 30 is degraded, and stops energizing the heater wire 32 regardless of the information of the temperature detected by the temperature detection wire 34 , and continues to stop energizing. This processing is the same processing as S15 described above.

Thus, according to the present embodiment, by continuing to stop the energization of the heater wire 32 based on the temperature of the wire heater 30 , deterioration of the wire heater 30 can be detected early before the thermal fuse TF1 is blown.

In addition, in the third embodiment, the case where the temperature information of multiple points of the line heater 30 is frequently acquired for a certain period of time to calculate the average temperature has been described, but it is also possible to use the temperature information of multiple points of the line heater 30 The temperature when the temperature switches from rising to falling (upper limit temperature), and the temperature when switching from falling to rising (lower limit temperature) are stored, and the average temperature is calculated from the upper limit temperature and lower limit temperature at multiple points.

Alternatively, the upper limit average temperature may be calculated only by calculating the average value based on the upper limit temperature at multiple points for a certain period of time, and the difference from the upper limit average temperature of the wire heater 30 when there is no leakage current may be calculated to determine whether it is a predetermined value (threshold value Th). above.

Alternatively, the average temperature at multiple points of the wire heater 30 may be compared with a predetermined temperature (threshold Ti), and if the temperature exceeds the predetermined temperature, continuation of energization to the heater wire 32 may be stopped. Alternatively, the upper limit average temperature at multiple points of the wire heater 30 may be compared with a predetermined temperature (threshold Tj), and if the temperature exceeds the predetermined temperature, continuation of energization to the heater wire 32 may be stopped.

In addition, the cycle of energization and energization stop in the first embodiment may be replaced with the cycle when the temperature of the wire heater 30 is switched from rising to falling, or the cycle of the on state of energizing the heater wire 32 in the first embodiment may be replaced. The time HH is replaced by the time when the temperature of the wire heater 30 rises, or the time HL in the off state when the heater wire 32 of the first embodiment is not energized is replaced by the time when the temperature of the wire heater 30 falls, etc., to detect wire heating. Deterioration of device 30.

(fourth embodiment)

In the fourth embodiment, the energization control unit 50 continues to stop energization to the heater wire 32 based on the information of the voltage to be applied corresponding to the leakage current to the voltage detected by the temperature detection wire 34 .

Fig. 12 is a diagram showing an example of the internal structure of a planar heating tool 100 according to the fourth embodiment.

Here, the block diagram of the energization control unit 50 is added to the planar heating tool 100 .

The energization control unit 50 has a half-wave rectification & zero-cross detection unit 121 , a sampling pulse generation unit 122 , a voltage detection unit 123 , a subtractor 124 , a comparator 125 , and a smoothing circuit 38 .

The half-wave rectification & zero-cross detection unit 121 detects the timing of the negative half-wave of the AC power supply in which a voltage corresponding to the leakage current is not generated even if there is a leakage current. The sampling pulse generator 122 generates a sampling pulse based on the timing of the negative half wave detected by the half-wave rectification & zero-cross detection unit 121 .

FIG. 13 is a diagram for explaining processing performed by the half-wave rectification & zero-cross detection unit 121 and the sampling pulse generation unit 122 .

FIG. 13( a ) is a diagram showing a waveform of an AC power input to the half-wave rectification & zero-cross detection unit 121 . The half-wave rectification & zero-cross detection unit 121 rectifies the negative half-wave based on the waveform of the input AC power supply.

Fig. 13(b) is a diagram showing a waveform after rectifying the negative half-wave. The half-wave rectification & zero-cross detection unit 121 detects the timing at which the voltage value crosses 0 [v] (zero-cross) based on the rectified waveform.

FIG. 13( c ) is a diagram showing a waveform after the timing at which the voltage value crosses 0 [v] (zero crossing point) is detected. The sampling pulse generator 122 generates a sampling pulse every predetermined time from the timing of generating the voltage.

FIG. 13( d ) is a diagram showing the timing at which sampling pulses are generated. The sampling pulse generation unit 122 outputs the generated sampling pulse to the voltage detection unit 123 .

The voltage value of the temperature detection line 34 at the branch point A before being smoothed is input to the voltage detection unit 123 . The voltage detection unit 123 measures the voltage value of the temperature detection line 34 at the timing of the sampling pulse output from the sampling pulse generation unit 122 . Therefore, the voltage detection unit 123 can measure the voltage value Vso of the temperature detection line 34 when there is no leakage current even if there is a leakage current.

The smoothing circuit 38 smoothes the voltage value of the temperature detection line 34 at the branch point A. Therefore, when there is a leakage current, the smoothing circuit 38 outputs the voltage value (Vso+ΔV) added corresponding to the leakage current. In addition, the smoothing circuit 38 outputs the voltage value Vso of the temperature detection line 34 when there is no leakage current.

The subtracter 124 subtracts the voltage value measured by the voltage detection unit 123 from the voltage value output by the smoothing circuit 38 , and outputs the subtracted value to the comparator 125 . For example, when there is a leakage current, the subtracter 124 subtracts the voltage value Vso measured by the voltage detection unit 123 from the voltage value (Vso+ΔV) output from the smoothing circuit 38 and added corresponding to the leakage current to obtain The voltage value ΔV is output to the comparator 125 .

The comparator 125 compares the voltage value output from the subtractor 124 with a predetermined threshold value, and when the voltage value is equal to or greater than the predetermined threshold value, energization to the heater wire 32 is stopped, and continuation energization is stopped.

FIG. 14 is a flowchart showing an example of processing performed by the energization control unit 50 in the fourth embodiment.

In S40 , the energization control unit 50 obtains the voltage value of the temperature detection line 34 smoothed by the smoothing circuit 38 while the heater wire 32 is energized. Specifically, the energization control unit 50 can obtain the smoothed voltage value of the temperature detection line 34 by measuring the voltage value input to the control unit 40 . As described above, as the leakage current increases, the voltage value of the temperature detection line 34 increases.

In S41 , the energization control unit 50 calculates the difference between the acquired voltage value of the temperature detection line 34 and the voltage value of the temperature detection line 34 when there is no leakage current. Here, the voltage value of the temperature detection line 34 when there is no leakage current can be obtained by the voltage detection unit 123 measuring the voltage value of the temperature detection line 34 at the timing of the sampling pulse generated by the sampling pulse generation unit 122 as described above. In addition, the voltage value of the temperature detection line 34 when there is no leakage current may be previously stored in the memory in the energization control unit 50 as a value corresponding to the temperature level set by the temperature setting unit 21 . In addition, the energization control part 50 may repeat S40-S41 several times, and may calculate the average value of a difference.

In S42, the energization control unit 50 determines whether or not the difference in voltage value is equal to or greater than a predetermined value (threshold value Vc). If the difference is equal to or greater than the predetermined value, the process proceeds to S43, and if it is not greater than the predetermined value, the process returns to S40. . The predetermined value is stored in advance in a memory in the energization control unit 50 , and is constant regardless of the temperature level set by the temperature setting unit 21 . In addition, the predetermined value is set to a value smaller than the difference between the voltage value when the thermal fuse is blown and the voltage value when there is no leakage current. In addition, the difference in voltage values may be an average value calculated by repeating S40 to S41 a plurality of times.

In S43 , the energization control unit 50 determines that the wire heater 30 has deteriorated, stops energization to the heater wire 32 , and stops continuation of energization. This processing is the same processing as S15 described above.

Thus, according to the present embodiment, by continuing to stop the energization of the heater wire 32 based on the information on the temperature of the temperature detection wire 34 smoothed by the smoothing circuit 38, wire heating can be detected as early as possible before the thermal fuse TF1 is blown. Deterioration of device 30.

In the fourth embodiment, the case of calculating the difference between the smoothed voltage value of the temperature detection line 34 and the voltage value of the temperature detection line 34 when there is no leakage current is described. The smoothed voltage value of the temperature detection line 34 during the energization time of the heater line 32 is compared with a predetermined voltage value (threshold value Vd), and the energization of the heater line 32 is continued and stopped when the predetermined voltage value is greater than or equal to the predetermined voltage value.

(fifth embodiment)

In the fifth embodiment, the energization control unit 50 continues to stop the energization of the heater wire 32 based on the information of the voltage detected by the temperature detection wire 34 corresponding to the leakage current.

Fig. 15 is a diagram showing an example of the internal structure of a planar heating tool 100 according to the fifth embodiment.

Here, the block diagram of the energization control unit 50 is added to the planar heating tool 100 . In addition, the same structure as FIG. 12 is given the same code|symbol, and description is abbreviate|omitted. The energization control unit 50 is located between the branch point A and the smoothing circuit 38 .

The energization control unit 50 has a delay unit 126 . The voltage value of the temperature detection line 34 at the branch point A before being smoothed is input to the delay unit 126 . The delay unit 126 measures the peak voltage value of each half-wave output of the AC power supply among the input voltage values, and causes the subtracter 124 to delay the measured peak voltage value and output it. This delay is to match the timing at which the voltage value of the temperature detection line 34 is measured by the voltage detection unit 123 . Furthermore, the delay unit 126 sequentially outputs the measured voltage values including the peak voltage value to the smoothing circuit 38 .

The subtracter 124 subtracts the voltage value measured by the voltage detection unit 123 from the voltage value output by the delay unit 126 , and outputs the subtracted value to the comparator 125 . The comparator 125 compares the voltage value output from the subtractor 124 with a predetermined threshold, and when the voltage value is greater than the predetermined threshold, the energization to the heater wire 32 is stopped, and the continuation of the energization is stopped.

FIG. 16 is a flowchart showing an example of processing performed by the energization control unit 50 of the fifth embodiment.

In S50 , the energization control unit 50 acquires the peak voltage value of the temperature detection line 34 before being smoothed by the smoothing circuit 38 while the heater wire 32 is energized. Specifically, the energization control unit 50 can acquire the voltage value of the temperature detection line 34 before being smoothed by measuring the voltage value at the branch point A shown in FIG. 3 . As described above, if there is a leakage current, a voltage is generated corresponding to the leakage current for every alternating half-wave.

In S51 , the energization control unit 50 calculates the difference between the acquired peak voltage value of the temperature detection line 34 and the voltage value of the temperature detection line 34 when there is no leakage current. Here, the voltage value of the temperature detection line 34 when there is no leakage current can be obtained by the voltage detection unit 123 measuring the voltage value of the temperature detection line 34 at the timing of the sampling pulse generated by the sampling pulse generation unit 122 . In addition, the voltage value of the temperature detection line 34 when there is no leakage current may be stored in memory in the energization control unit 50 in advance as a value corresponding to the temperature level set by the temperature setting unit 21 .

In S52, the energization control unit 50 determines whether or not the difference in voltage value is greater than or equal to a predetermined value (threshold Ve), and if the difference is greater than or equal to the predetermined value, proceeds to S53, and if not greater than the predetermined value, returns to S50. . The predetermined value is stored in advance in a memory in the energization control unit 50 , and is constant regardless of the temperature level set by the temperature setting unit 21 . In addition, the predetermined value is set to a value smaller than the difference between the voltage value when the thermal fuse is blown and the voltage value when there is no leakage current.

In S53 , the energization control unit 50 determines that the wire heater 30 has deteriorated, stops the energization to the heater wire 32 , and continues to stop the energization. This processing is the same processing as S15 described above.

Thus, according to the present embodiment, based on information on the temperature of the temperature detection wire 34 before being smoothed by the smoothing circuit 38, by continuing to stop the energization of the heater wire 32, the wire can be detected earlier before the thermal fuse TF1 is blown. Deterioration of the heater 30 .

In addition, in the fifth embodiment, the case of calculating the difference between the peak voltage value of the temperature detection line 34 before being smoothed and the voltage value of the temperature detection line 34 when there is no leakage current has been described, but the The peak voltage value of the temperature detection line 34 before being smoothed is compared with a predetermined voltage value (threshold value Vf), and when the predetermined voltage value is greater than or equal to the predetermined voltage value, energization to the heater line 32 is continuously stopped.

As mentioned above, the present invention has been described using the above-mentioned embodiment and each example, but the present invention is not limited to the above-mentioned embodiment and each example, and changes and the like can be made within the scope of the present invention. An appropriate combination of examples.

In the above-mentioned embodiment, the case where the planar heating tool is an electric blanket has been described, but it is not limited to this case, and it can also be applied to an electric heating pad, an electric heating blanket, and the like. In addition, it is not limited to the product of AC 100V, and it can apply also to the product of AC 200V.

Claims (10)

1. A planar heating tool comprises:

a wire heater wired in the heating section and having a heater wire, a temperature detection wire, and an intermediate layer located between the heater wire and the temperature detection wire; and

a control means for controlling the temperature of the heating section by alternately switching between energization and interruption of the heater wire based on information of the temperature detected by the temperature detection wire,

it is characterized in that the preparation method is characterized in that,

the control means continues the stop of the energization of the heater wire based on information on at least one of the energization and the stop of the energization of the heater wire.

2. Planar heating tool according to claim 1,

the information on at least one of the energization and the energization stop of the heater line is:

information on the period of energization and energization stop of the heater line;

information on the time when the heater wire is energized;

information on a time when the heater wire is powered on and off; or

Information on the number of times of at least one of energization and energization stoppage of the heater line.

3. Planar heating tool according to claim 2,

the control mechanism is as follows

In the case where the above-mentioned period is below the threshold,

when the time for which the heater wire is energized is equal to or less than a threshold value,

when the time for which the heater wire is not energized is equal to or less than a threshold value,

or the number of times of at least one of the energization and the stoppage of the heater wire is equal to or more than a threshold value,

the energization of the heater wire is continuously stopped regardless of information on the temperature detected by the temperature detection wire.

4. The planar heating tool as claimed in claim 2,

the control mechanism is as follows

When the difference between the period and the period of the heater line in which the current is supplied to and stopped from the heater line when there is no leakage current is equal to or greater than a threshold value,

in the case where the difference between the time when the heater wire is energized and the time when the heater wire is energized in the absence of the leakage current is equal to or greater than the threshold value,

when the difference between the time when the heater wire is energized and stopped and the time when the heater wire is energized and stopped without leakage current is equal to or greater than a threshold value,

the energization of the heater wire is continuously stopped regardless of information on the temperature detected by the temperature detection wire.

5. Planar heating tool according to claim 4,

has a temperature fuse for cutting off the energization to the heater wire,

the threshold value is a value smaller than a difference between a period of energization and energization stop of the heater line when the thermal fuse disconnects energization to the heater line and a period of energization and energization stop of the heater line when there is no leakage current.

6. The planar heating tool according to any one of claims 1 to 4,

has a temperature fuse for cutting off the energization to the heater wire,

the control means continues to stop the energization of the heater wire before the thermal fuse breaks the energization.

7. The planar heating tool according to any one of claims 1 to 6,

the control means notifies the user of the fact that the heater wire is continuously energized and stopped via a notification unit.

8. A planar heating tool comprises:

a wire heater wired in the heating section, and having a heater wire, a temperature detection wire, and an intermediate layer located between the heater wire and the temperature detection wire;

a control means for controlling the temperature of the heating unit by alternately switching between energization and interruption of energization to the heater wire based on information on the temperature detected by the temperature detection wire; and

a temperature detection mechanism which is separated from the temperature detection line and detects the temperature of the line heater,

it is characterized in that the preparation method is characterized in that,

the control means continues the stop of the energization of the heater wire based on the information of the temperature detected by the temperature detection means.

9. A planar heating tool, comprising:

a wire heater wired in the heating section, and having a heater wire, a temperature detection wire, and an intermediate layer located between the heater wire and the temperature detection wire; and

a control means for controlling the temperature of the heating section by alternately switching between energization and interruption of energization to the heater wire based on information of the temperature detected by the temperature detection wire,

it is characterized in that the preparation method is characterized in that,

the control means continues the stop of the energization of the heater wire based on the information on the temperature detected by the temperature detection line and the information on the temperature detected by the temperature detection line when there is no leakage current.

10. Planar heating tool according to claim 9,

a smoothing means for smoothing information on the temperature detected by the temperature detection line,

the control means continues the stop of the energization of the heater wire based on the information that the information of the temperature detected by the temperature detection wire is smoothed by the smoothing means.

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