JP2006351456A - Temperature control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature control device safely controlling a heating element from high temperature to low temperature with good accuracy even if a heat sensing layer absorbs moisture. <P>SOLUTION: The temperature control device has a first temperature detection part 9a detecting temperature from a temperature sensing layer signal and a second temperature detection part 9b detecting temperature from a heat generating resistant wire signal of the heating element 6. The temperature of the first temperature detection means 9a and the second temperature detection means 9b is compared, and when it is judged so that the temperature of the first temperature detection means 9a is higher than that of the second temperature detection means 9b, it is corrected so as to lower the temperature of the first temperature detection member 9a. As a result, it is eliminated to control the heating element 6 by a bit lower temperature even if a temperature a bit higher than normal temperature is detected by moisture absorption of the temperature sensing layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a temperature control device for a flexible linear heating element used in, for example, an electric warming instrument.

  Conventionally, a flexible linear heating element is generally employed as a heating means used for an electric warming instrument or the like.

  The flexible linear heating element has a configuration in which a core conductor is wound with a first conductor wire in a spiral shape, a temperature-sensitive layer is provided thereon, and a second conductor wire is formed thereon from the first conductor wire. On the contrary, it was wound in a spiral and covered with a jacket insulating layer (for example, see Patent Document 1).

  The temperature signal of the flexible linear heating element mainly depends on the temperature-sensitive characteristics of the temperature-sensitive layer, but the contact state between the temperature-sensitive layer, the first conductor wire, and the second conductor wire. Is also greatly related. In particular, in the configuration in which the second conductor wire is used as the heating resistance wire of the heating element, the second conductor wire needs to be thickened to obtain a low resistance value.

  Therefore, after the temperature-sensitive layer is spirally wound, a phenomenon occurs in which the adhesion between the second conductor wire and the temperature-sensitive layer deteriorates due to a springback phenomenon. This deterioration in adhesion has a problem in that the temperature dependency of the temperature-sensitive layer impedance (hereinafter referred to as B constant) is small when the heating element is in a low temperature range, so that the control temperature variation in the low temperature range becomes large.

In response to this problem, the heating element is controlled by the temperature-sensitive layer signal in the high-temperature range where the variation is less affected, and conversely, it is not related to the temperature-sensitive layer signal in the low-temperature range where the variation is significant. No timer control was performed (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 2-54885 JP-A-6-13159

  However, in the conventional configuration, when the heating element is not energized for a long period of time, the material used for the temperature sensitive layer (especially nylon resin) absorbs moisture, and the temperature sensing characteristic detects the temperature higher (temperature sensing). It shifts to the side where the layer impedance becomes lower. This phenomenon becomes normal impedance-temperature characteristics when the moisture in the temperature sensitive layer disappears during use for several days, but the heating element may absorb moisture at the beginning of use in the heating season, etc. There is a problem that the heating element is turned off even though the heating device such as the carpet is not yet heated.

  In addition, since the timer control is simple in the low temperature range, there is a problem that it is not known how many times the carpet surface temperature becomes with respect to the setting.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a temperature control device capable of controlling a heating element accurately and safely from a high temperature to a low temperature.

In order to solve the above-described conventional problems, the present invention compares the temperature of the heating element calculated from the temperature-sensitive layer signal with the temperature of the heating element calculated from the resistance wire signal, and is calculated from the temperature-sensitive layer signal. If the temperature of the heating element is determined to be higher than the temperature of the heating element calculated from the resistance wire signal, a correction is applied to the side where the temperature detection of the heating element calculated from the temperature sensing layer signal is low. However, even if the temperature is detected high due to moisture absorption or the like, the temperature of the heating element can be prevented from being controlled to be low.

  Further, in the region where the B constant of the heat sensitive layer is large and the temperature change signal is large, energization to the heat generating element is stopped based on at least the temperature of the heat generating element calculated from the temperature sensitive layer signal, and the B constant of the temperature sensitive layer is small. In the region where the temperature change signal is small, the heating element is turned on based on the temperature calculated from the signal of the heating resistance line, and the control target temperature can be set also on the low temperature side.

  The temperature control device of the present invention can perform safe and efficient temperature control from high temperature to low temperature with high accuracy even if there is a characteristic variation factor from inside and outside the temperature sensitive layer.

  In the first invention, a temperature signal line is spirally wound around the outer periphery of the core yarn, the outer periphery thereof is covered with a temperature-sensitive layer, and a heating resistance wire is spirally wound around the outer periphery of the temperature-sensitive layer. A heating element formed with an outer insulating layer; first temperature detecting means for detecting temperature from the temperature sensitive layer signal; and second temperature detecting means for detecting temperature from a resistance line signal of the heating resistance line; An energization control unit that controls energization to the heating element according to the temperatures of the first temperature detection unit and the second temperature detection unit, and the energization control unit includes the temperature of the first temperature detection unit, When the temperature of the first temperature detection means is compared with the temperature of the second temperature detection means and it is determined that the temperature of the first temperature detection means is higher than the temperature of the second temperature detection means, the temperature of the first temperature detection means is corrected. The temperature sensitive layer is hygroscopic by having a correction means for applying Accordingly, even if the high temperature detection temperature of the heating element no longer possible to control the temperature of the heating element low.

  In the second invention, in particular, an upper limit temperature is set for the temperature of the first temperature detecting means of the first invention, and when the temperature of the first temperature detecting means exceeds the upper limit temperature, energization to the heating element is forced. Therefore, even if the heating element is partially heated or kept warm, it can be prevented from becoming an abnormal temperature.

  The third invention uses at least the temperature of the first temperature detecting means when turning off the power to the heating element of the first or second invention, and detects the second temperature when turning on the heating element. The temperature of the means is used. As a result, the temperature detection means is switched between the side where the relatively high temperature heating element is turned off and the side where the relatively low temperature heating element is turned on, so temperature control with little variation from high temperature to low temperature is possible. In addition to this, the control target temperature can also be set for the low temperature side.

  The fourth invention uses at least the temperature of the first temperature detecting means when the energization to the heating element of the first or third invention is turned off, and when the heating element is turned on, the heat generating pair is turned off. At the same time, the heating element is turned on only when the temperature of the second temperature detection means is lower than the temperature at which the heating element is turned on when the timer means activated at the same time expires. As a result, it is possible to set a period for turning off the energization of the heating element to a certain time or longer, and it is possible to prevent the energization of the heating element unnecessarily.

  In the fifth aspect of the invention, in particular, the first to fourth temperature control devices are mounted on an electric warming instrument, and accurate warming is possible.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
In FIG. 1, a temperature signal line 2 is wound spirally around a core yarn 1 and a temperature sensitive layer 3 is coated thereon, and a heating resistance wire 4 is wound spirally around the temperature sensitive layer 3. Further, the flexible linear heating element 6 is configured by covering the outer insulating layer 5.

  The core yarn 1 is made of polyester or polyamide fiber, the temperature signal wire 2 is copper or copper alloy wire, the temperature sensitive layer 3 is nylon, the heating resistance wire 4 is copper or copper alloy wire, The insulating layers 5 are each formed of vinyl chloride resin (PVC).

  The spiral direction of the core yarn 1 and the spiral direction of the heating resistance wire 4 are set to be opposite to each other.

  Here, the temperature signal line 2 is a conducting wire for deriving a temperature signal from the impedance change of the temperature sensitive layer 3, and a relatively thin wire is used, and the heating resistance wire 4 functions as a heating element, so that it is a relatively thick wire. Is used. The temperature sensitive layer 3 is obtained by adding an additive to a nylon-based resin material and has impedance-temperature characteristics shown in FIG. Note that FIG. 2 shows a logarithmic scale.

  As apparent from FIG. 2, the B constant in the temperature range of 80 ° C. or lower is relatively small, whereas the B constant in the temperature range of 80 ° C. or higher shows a large value. This is because the temperature change characteristic of the capacitance mainly appears in the low temperature range because the material of the temperature sensitive layer 3 is based on nylon, whereas the temperature change characteristic of the resistance component appears strongly in the high temperature range. .

  Further, FIG. 3 shows a resistance temperature characteristic of the heating resistance wire 4. The resistance value of the heating resistance wire 4 increases in proportion to the temperature, and the temperature of the heating resistance wire 4 can be detected by detecting the value of this resistance value.

  Next, a control circuit used in the temperature control device is shown in FIG. The heating resistance wire 4 is connected in series to the power source via the contact 7a of the relay 7. Further, the temperature signal line 2 of the temperature sensitive layer 3 is connected to the first temperature detecting means 9a provided in the energization control unit 9 through the semiconductor element 8, and the signal is converted into temperature.

  Further, the temperature signal from the heating resistor wire 4 is pulled up by the resistor 11 through the diode 10 from the connection portion of the relay contact 7a, and converted into temperature by the second temperature detecting means 9b provided in the previous energization control section 9. Is done.

  The drive circuit of the relay 7 includes a relay coil, and is configured to be controlled by a control element 12 that is turned on and off by an output signal of the energization control unit 9.

  The energization control unit 9 is composed of a memory, a signal comparison, a one-chip microcomputer having a calculation function, and the like.

  In the above configuration, when the heating element 6 absorbs moisture now, for example, in a temperature range of 80 ° C. or lower, the impedance is high and is easily affected by moisture absorption, and the temperature characteristic of the heating element (temperature change characteristic of impedance) is shown in FIG. As shown by the broken line in FIG. When the above characteristic change occurs, even if the signal from the temperature sensitive layer 3 is simply converted into temperature and the impedance is equivalent to 80 ° C., the actual temperature becomes about 70 ° C., and the heating element is controlled to be low. .

In addition, since the heating element control is performed in a state where the temperature is low, the absorbed moisture is difficult to evaporate, and the lower control is continued for a long time. On the other hand, the resistance value of the heating resistor line 4 is not affected at all by the humidity, and its resistance temperature characteristic remains as shown in FIG. By correcting the temperature calculated from the signal of the layer 3, the heating element can be controlled at a normal temperature even if moisture is absorbed and the temperature is detected on the higher side. The operation at this time will be described with reference to the flowchart of FIG.

  First, the temperature correction a is initialized in step S1, the heating element is turned on in step S2, and the temperature ST from the temperature sensitive layer signal is detected by the first temperature detection means 9a in step S3.

  Next, compared with an abnormal temperature ST1 (for example, 120 ° C.) provided in advance in step S4, if the temperature is equal to or higher than ST1, energization of the heating element is stopped in step S6 as a high temperature abnormality in step S5. If it is less than ST1, in step S7, the temperature obtained by subtracting the temperature correction a from the temperature ST from the temperature-sensitive layer signal is compared with the heating element off temperature (for example, 85 ° C.) in the preset normal temperature range to generate heat. If it is lower than the body off temperature, the process returns to step S2.

  If it is higher than the heating element off temperature, the heating element is turned off in step S8. Next, in step S9, the temperature HT from the resistance wire signal of the heating element is detected by the second temperature detecting means 9b. In step S10, a difference ΔT (ST−HT) between the temperature ST of the first temperature detecting means 9a in step S3 and the temperature HT from the second temperature detecting means 9b detected in step S9 is calculated.

  In step S11, if the calculated ΔT is larger than a predetermined temperature T0 (for example, 5 ° C.), it is determined that the temperature of the temperature sensitive layer is too high, and ΔT is added to the correction value a in step S12. If it is smaller than T0, zero is entered in the correction value a in step S13. In step S14, the temperature HT detected by the second temperature detecting means 9b in step S9 is compared with a predetermined heating element ON temperature (for example, 75 ° C.), and the temperature HT detected by the second temperature detecting means 9b in step S9 is It waits until it becomes lower than the predetermined heating element ON temperature, and when it becomes lower, it returns to step S2.

  As described above, in the present embodiment, the temperature ST of the heating element calculated from the temperature-sensitive layer signal is compared with the temperature HT of the heating element calculated from the resistance wire signal, and the temperature of ST is the temperature of HT. If the temperature is higher than the actual temperature, the heating element is controlled by the SHT temperature, which is corrected on the lower temperature detection side of the ST, so only when the temperature sensing layer detects a temperature higher than the actual temperature due to moisture absorption or the like. The temperature can be corrected on the lower side.

  In this embodiment, the difference ΔT between the temperature calculated from the temperature-sensitive layer signal as the correction temperature and the temperature calculated from the resistance wire signal of the heating element is defined as the correction temperature a. It is also conceivable that weighting is applied according to the degree of influence so that the amount of the water becomes an amount commensurate with the amount displaced due to moisture absorption. For example, ΔT is corrected as it is near 80 ° C., but ΔT × 0.9 near 90 ° C., and ΔT × 1.1 near 70 ° C. can be corrected more accurately.

  In addition, although an example has a dead zone region in which the correction is activated when the difference between the temperature calculated from the temperature-sensitive layer signal and the temperature calculated from the resistance wire signal of the heating element is 5 ° C. or more, It is not limited.

  Furthermore, the heating element on-temperature and off-temperature of this embodiment do not have to be fixed to one value, and the same effect can be obtained even if a plurality of temperature-adjusting functions are provided.

(Embodiment 2)
7 and 8 show the second embodiment of the present invention, and the same reference numerals are given to the configurations that exhibit the same action as the first embodiment, and the detailed description of the first embodiment is used. .

  In FIG. 7, a timer 9c that is activated when the heating element 6 is turned off and stopped when the heating element 6 is turned on is added to the energization control unit 9.

  The operation of the above configuration will be described with reference to the flowchart of FIG.

  When the heating element is turned off in step S8, the timer 9c is started in step S20. After the correction value a is determined in steps S11, S12, and S13, the timer 6c is checked for an overflow in step S21. The heating element is continuously turned on or off in accordance with the temperature HT detected by the resistance line signal in step S9.

  As described above, in this embodiment, after the heating element is turned off, the heating element is controlled according to the temperature HT of the heating element calculated from the resistance wire signal after securing the minimum timer 9c. It is possible to eliminate unnecessary energization of the heating element and reduce the frequency of relay opening and closing.

  As described above, the temperature control device according to the present invention can correct the temperature to the lower side only when it is determined that the temperature-sensitive layer has detected a high temperature due to moisture absorption or the like. Even if there is a characteristic variation factor from the outside, it is safe and efficient from high temperature to low temperature, and accurate temperature control can be performed. Therefore, it can be applied to heating purposes such as electric carpets and electric blankets.

Partially cutaway side view of a heating element in Embodiment 1 of the present invention Temperature characteristics of impedance of the same heating element Resistance-temperature characteristics of the same heating element Control circuit diagram Diagram showing temperature characteristics of the same impedance Operation flowchart of the control device Circuit diagram showing Embodiment 2 of the present invention Same operation flowchart

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core thread 2 Temperature signal line 3 Temperature sensitive layer 4 Heating resistance wire 5 Outer insulation layer 6 Heat generating body 9 Current supply control part 9a First temperature detection means 9b Second temperature detection means 6c Timer means

Claims (5)

Constructed by spirally winding a temperature signal wire around the outer periphery of the core yarn and covering it with a temperature-sensitive layer, and further winding a heat-generating resistance wire spirally around the outer periphery of this temperature-sensitive layer and covering the outer periphery with an outer insulation layer A flexible heating element, a first temperature detecting means for detecting a temperature from a signal of the temperature sensitive layer, a second temperature detecting means for detecting a temperature from a resistance wire signal of the heating resistance wire, and the first temperature An energization control unit that controls energization to the heating element according to the temperature of the detection unit and the second temperature detection unit, and the energization control unit includes the temperature of the first temperature detection unit and the second temperature detection unit If the temperature of the first temperature detecting means is determined to be higher than the temperature of the second temperature detecting means by calculating the difference from the temperature of the means, the correction is made so that the temperature of the first temperature detecting means is lowered. A temperature control device designed to be applied. The temperature control according to claim 1, wherein the energization control unit has an upper limit temperature of the temperature sensitive layer signal, and forcibly stops energization to the heating element when the temperature of the first temperature detection means exceeds the upper limit temperature. apparatus. The energization control unit uses at least the temperature of the first temperature detecting means when turning off the energization to the heating element, and uses the temperature of the second temperature detecting means when turning on the heating element. 2. The temperature control apparatus according to 2. The energization control unit has a timer unit that is activated when the heating element is turned off. When the energization to the heating element is turned off, at least the temperature of the first temperature detection unit is used and the heating element is turned on. 3. The temperature control device according to claim 1, wherein the heating element is turned on only when the temperature of the second temperature detection means is lower than the heating element on temperature when the timer means expires. An electric warming instrument equipped with the temperature control device according to any one of claims 1 to 4.