JP5418153B2 - electric blanket - Google Patents

Description

  The present invention relates to an electric blanket having a heater, and more particularly to an electric blanket for heating a laid mat.

  A large number of heat storage elements made of materials having a high cold storage effect are used as a cold storage agent in various fields such as transportation and medical use. Moreover, since this heat storage body also has a high heat storage effect, the mat of the heat storage body can be used as a heat insulating material for bedding. The temperature drop when the mat is left between the futons is as small as 6 ° C in 15 hours, so it is somewhat warm when used again. Since this heat storage mat does not include a heater, it needs to be warmed in some way, for example, with a kotatsu or hot carpet in advance, or with an electric blanket during sleeping.

  However, there is a problem that the method of warming the heat storage mat with a kotatsu or a hot carpet cannot be performed while sleeping. On the other hand, the method of warming the mat with an electric blanket can warm the heat storage body while sleeping. However, since the temperature of the normal electric blanket is not designed to heat the mat of the heat storage body, there is a problem that the surface temperature of the mat on the human body side cannot be increased to an appropriate temperature. In addition, none of the methods controls the temperature of the mat of the heat storage body to be a predetermined temperature, and there is a problem that the temperature of the mat cannot be set to an appropriate temperature.

  Therefore, Patent Document 1 discloses a technique for heating the heat storage body with a heater. FIG. 9A is a plan view showing a conventional heat storage mat with a heater, and FIG. 9B is a cross-sectional view of the conventional heat storage mat with a heater.

  As shown in FIG. 9A, the heat storage mat 50 described in the embodiment of Patent Document 1 is partitioned into four partition bags 50a. The three partition bags 50a on the right side of FIG. 2, 3rd heating element 51,52,53 is provided in order. Each of the first, second, and third heating elements 51, 52, and 53 is provided with a heater 54, and a temperature switch 55 is provided at an important point of the heater 54. As shown in FIG. 9B, the first, second, and third heating elements 51, 52, and 53 include a heat storage body 57 impregnated in an impregnating base material 56 such as polyester felt. The heat storage body 57 is a sodium acetate system having a large transformation latent heat, liquefies by being heated, and serves as a temperature detection means. The transformation temperature of the heat storage body 57 is 50 ° C., 55 ° C., and 58 ° C. for the first, second, and third heating elements 51, 52, and 53 in this order. The impregnated base material 56 impregnated with the heat storage body 57 is enclosed in a bag body 58 made of laminated aluminum foil. A heater 54 is disposed below the bag body 58 in FIG. 9B, and an aluminum foil 59 is bonded to the bottom of the bag body 58 with the heater 54 interposed therebetween. The bag body 58 to which the aluminum foil 59 is bonded is sandwiched between a cushion 60 on the upper side of FIG. 9B and cushions 61 and 62 on the lower side of FIG. 9B and enclosed in a partition bag 50a. With such a configuration, the heat storage body 57 of the heat storage mat 50 of Patent Document 1 is warmed by the heater 54 even while sleeping.

Japanese Utility Model Publication No. 2-42266 JP 2001-76846 A

  However, Patent Document 1 discloses a method for warming the heat storage body even while sleeping, but does not disclose a specific method for attaching the temperature switch 55. For this reason, it is difficult to derive a specific temperature control method for the mat of the heat storage body based on Patent Document 1. Further, since the mat of the heat storage body does not include the impregnating base material 56, the temperature detecting means for detecting the temperature of the mat on the human body side or the surface of the heat storage body cannot be sandwiched between the mat and the heat storage body having high viscosity. . For this reason, a holding member for attaching the temperature detecting means is required, and the material cost and labor cost are increased.

  In addition, when the heat storage mat and the heater are integrated, it is inconvenient to clean the mat, dry the sweat, or replace the mat with another mat. In addition, since the heat storage industry and the heater industry are different, it is not easy to design and manufacture a product in which the heat storage mat and the heater are integrated.

  Therefore, in order to solve the above problems, the inventors have come up with the development of an electric blanket for heating a mat of a conventional heat storage body that does not include a heater. However, as disclosed in Patent Document 2, a heater having a temperature detection function is used for a normal electric blanket, and temperature control is performed by detecting the temperature of the heater. If a circuit for controlling heat with a temperature sensor is added, the price increases and the heat control becomes complicated. Therefore, without attaching temperature detection means to the mat of the heat accumulator, and without changing any hardware configuration such as the control circuit of the existing electric blanket, the electric blanket can be stored in the heat accumulator by changing only the control software. The use of such mats for heat insulation has been the subject of the development of a new electric blanket as described above.

  In this development, differences in the heat dissipation environment must also be considered. The difference in the environment is firstly the difference in the room temperature at bedtime. If the room temperature is low, heat dissipation increases, so a large amount of power must be supplied to the heater. In addition, heat dissipation from comforters and mattresses is also affected. For example, since a thin comforter increases heat dissipation, a large amount of power must be supplied to the heater. FIG. 10A is a diagram showing changes in the heater surface temperature of 20 ° C., 15 ° C., and 10 ° C. and the surface temperature of the heat storage body when the heater temperature control is not performed. I see, it gets lower. FIG. 10B is a diagram showing changes in the heater surface temperature of the thick comforter and the thin comforter and the surface temperature of the heat accumulator when the heater temperature control is not performed, and the thickness of the comforter becomes thin at any surface temperature. It gets lower. If this environment for heat dissipation is not taken into account, for example, when the room temperature is low and a thin futon, the heat dissipation may be very large and a cold may occur. There is a risk of low temperature burns. Even if only the room temperature is detected using an existing room temperature sensor on a conventional electric blanket, other heat dissipation environments (for example, the thickness of the above-mentioned futon, the environment of the bed or floor on which the electric blanket is laid) are considered. Otherwise, you may catch a cold or get a low-temperature burn.

  The present invention has been made to solve such problems of the prior art, and does not add a temperature detection means to the mat of the heat storage body, and changes the hardware configuration of the existing electric blanket. Without changing the control software alone, an electric blanket that can be used favorably to keep the mat of the heat accumulator, and with little change in the surface temperature of the mat even if there is a change in the heat dissipation environment, is supplied. The purpose is to do.

  In order to solve the above-mentioned problem, the electric blanket invention according to claim 1 is an electric blanket having a heater and heating a laid mat, the temperature detecting a temperature of a predetermined place of the electric blanket. A detection circuit; storage means for storing a temperature drop from a predetermined temperature at the predetermined location; and a table of the amount of electric power applied to the heater corresponding to the temperature drop; and the predetermined location at the time of applying electric power to the heater. When the temperature rise reaches the predetermined temperature, the heating to the heater is cut off, the temperature detection circuit detects the temperature drop at the predetermined location, and the heating to the heater corresponding to the detected temperature drop is detected. A thermal control circuit is provided that acquires the amount of electricity from the table of the storage means and controls the temperature of the heater with the acquired amount of applied electricity.

  Further, in the electric blanket according to claim 1, the invention according to claim 2 is that the predetermined temperature is a set temperature for thermal control in an environment where the amount of heat radiation is the smallest in the set heat radiation environment. Features.

  According to a third aspect of the present invention, in the electric blanket according to the first aspect, the thermal control circuit detects the temperature drop a plurality of times.

  According to a fourth aspect of the present invention, in the electric blanket according to the first aspect, the mat is a bedding.

  According to a fifth aspect of the present invention, in the electric blanket according to the first aspect, the thermal control circuit performs thermal control by changing a conduction rate, and the amount of applied electricity stored in the table is a conduction rate at a constant voltage. It is characterized by being.

  According to a sixth aspect of the present invention, in the electric blanket according to the first aspect, the storage means stores a set value of the temperature at the predetermined location corresponding to the temperature rise in the table, and the thermal control. The circuit acquires the set value corresponding to the detected temperature rise from the table of the storage means, and when the temperature of the predetermined location exceeds the acquired set value or more than the acquired set value Then, the power supply to the heater is stopped.

  According to a seventh aspect of the present invention, in the electric blanket according to the first aspect, the heater has a conductor for heating the mat and detecting the temperature.

  By providing the above configuration, the present invention has the following excellent effects. That is, according to the invention of the electric blanket according to claim 1, without detecting the temperature of the mat of the heat storage body, the temperature drop from a predetermined temperature is measured using the temperature detection means inherent to the electric blanket, The amount of electricity applied to the heater corresponding to the temperature drop is obtained from a table, and the temperature of the mat can be adjusted by controlling the temperature of the heater with the obtained amount of electricity applied. For this reason, it is not necessary to add a new sensor for detecting the temperature of the mat and the accompanying parts such as a circuit, and by changing only the control software without changing the hardware configuration of the electric blanket. In addition, the electric blanket can be suitably used to keep the heat storage mat mat warm. Further, if a table obtained from experimental data is used, a change in the surface temperature of the mat can be reduced. Further, since the electric blanket of the present invention does not detect the temperature of the mat, the heat storage mat and the heater can be separated. Thereby, it becomes easy to remove the dirt on the mat, dry the sweat, or replace the mat.

  According to the invention of claim 2, since the temperature drop is detected from the set temperature of the thermal control in the environment where the amount of heat radiation is the smallest, it is possible that the mat exceeds the appropriate temperature by the heating to the heater before the temperature drop is detected. Can be prevented.

  According to the invention of claim 3, since the thermal control circuit detects the temperature drop a plurality of times, the detection accuracy of the temperature drop can be increased. As the temperature drop value, a final detection value that is more stable than the first time may be adopted, or an average value of a plurality of detection values may be adopted.

  According to the invention of claim 4, in the electric blanket according to claim 1, even if the heat radiation is different due to the difference in the thickness or material of the bedding such as the comforter and the mattress, the change in the surface temperature of the mat can be reduced. it can.

  According to the fifth aspect of the present invention, in the electric blanket according to the first aspect, the present invention can be applied to an electric blanket in which thermal control is performed by changing the energization rate.

  According to the invention of claim 6, in the electric blanket according to claim 1, when the temperature of the mat of the heat storage body exceeds the set value or exceeds the set value without detecting the temperature of the mat of the heat storage body, the heater Stop energizing the. As a result, the surface temperature of the heat storage body becomes high in an abnormal state, and the user can be prevented from getting a low temperature burn.

  According to the seventh aspect of the present invention, the present invention can be applied even if an existing heater of an electric blanket is called a one-wire system that performs heating and temperature detection with a single conductor.

FIG. 1 is a cross-sectional view showing a usage state of the electric blanket according to the present embodiment. FIG. 2 is a plan view showing an outline of the electric blanket according to the present embodiment. 3A is a perspective view of the heater, and FIG. 3B is an equivalent circuit diagram of the heater. FIG. 4 is a block diagram showing an outline of the electric blanket according to the present embodiment. FIG. 5A is a diagram showing the measurement of the temperature drop of the heater for obtaining the energization rate table in the experiment, FIG. 5B is a diagram showing the energization rate of the thermal control, and FIG. 5C is the energization rate corresponding to the temperature drop. It is a figure which shows the table of. FIG. 6 is a flowchart showing the operation of the thermal control circuit. FIG. 7A is a diagram showing a change in temperature when the room temperature is different, and FIG. 7B is a diagram showing an energization rate when the room temperature is different. FIG. 8A is a diagram showing a change in temperature when the thickness of the comforter is different, and FIG. 8B is a diagram showing an energization rate when the thickness of the comforter is different. 9A is a cross-sectional view showing a conventional heat storage mat with a heater, and FIG. 9B is a cross-sectional view of a conventional heat storage mat with a heater. FIG. 10A is a diagram showing a temperature change when the room temperature is different and thermal control is not performed, and FIG. 10B is a diagram showing a temperature change when the comforter thickness is different and thermal control is not performed.

  The best mode for carrying out the present invention will be described below with reference to the embodiments and drawings. However, the embodiments shown below are not intended to limit the present invention to those described herein. The present invention can be equally applied to various modifications without departing from the technical idea shown in the claims.

  As shown in FIG. 1, the electric blanket 10 of this embodiment is laid on a mattress 30, a mat 31 is laid on the electric blanket 10, a human body 32 lies on the mat 31, and a comforter 33 is hung on the human body 32. In the mat 31, a heat storage body 35 made of a material having a high heat storage property is enclosed in a non-woven bag 34. The heat storage body is composed of, for example, a water-absorbing polymer, parapen, antifungal agent, glycerin, water, and the like, and has a heat storage property several tens of times that of water alone. Due to this heat storage property, the temperature of the heat storage body 35 is small. For example, the temperature drop after 15 hours of the 30 ° C. mat 31 left in the futon is about 7 ° C. In addition, the heat storage body 35 has a high viscosity and low repulsion, and since the body pressure can be well dispersed in order to fit the body, the heat storage body 35 also has a feature that the sleeping comfort is good.

  As shown in FIG. 1, the electric blanket 10 is configured such that a heater 11 is sandwiched between a first blanket fabric 12 and a second blanket fabric 13. The first blanket fabric 12 and the second blanket fabric 13 are made of acrylic and polyester, for example. As shown in FIG. 2, the heater 11 is wired in a zigzag manner between the rectangular first blanket fabric 12 and the second blanket fabric 13. Both ends of the heater 11 are connected to the controller 14. As shown in FIG. 3A, in the heater 11, a primary conductor 16 having a large resistance is wound around a core wire 15 made of a flexible resin such as polyester, and a layer of a plastic thermistor 17 is formed thereon. A secondary conductor 18 having a small resistance is wound around the outer cover 19, and a jacket 19 made of a flexible electrical insulating material such as vinyl chloride is formed thereon. The plastic thermistor 17 is made of a resin whose impedance changes with temperature, such as vinyl chloride, and can detect the temperature. As shown in FIG. 3B, the primary conductor 16 having a large resistance becomes a heat generating resistor and warms the heat storage body 35. The plastic thermistor 17 whose impedance changes is electrically connected to the primary conductor 16 and the secondary conductor 18 so that a temperature detection signal can be taken out by the primary conductor 16 and the secondary conductor 18. Thus, the heater 11 has a function of heating the heat storage body 35 and a function of detecting its own temperature.

  As shown in FIG. 4, the controller 14 to which the heater 11 is connected includes a switch 20, a temperature detection circuit 21, a thermal control circuit 22, a storage circuit 23, and a room temperature sensor 24. The primary conductor 16, which is a heating element, is connected to a commercial power supply 36 of AC 100V through the switch 20. The temperature detection circuit 21 is electrically connected to the primary conductor 16 and the secondary conductor 18 of the heater 11, detects the temperature of the heater 11, and outputs this to the thermal control circuit 22 as disclosed in Patent Document 2. To do. The storage circuit 23 stores in advance a program 25 for operating the thermal control circuit 22, an initial value 26 of ON time, and an energization rate table 27. The room temperature sensor 24 is a component when the electric blanket 10 is used as an existing electric blanket, and is exposed to the outside air and affected by the heating of the heater 11 so that the room temperature can be detected as the existing electric blanket. It is placed in a difficult position.

  With the above-described configuration, the heater surface temperature is detected by the temperature detection circuit 21 under the control of the thermal control circuit 22, and the detected heater surface temperature is input to the thermal control circuit 22. The detection of the heater surface temperature is performed intermittently both when the mat 31 is heated (when the heater described later is ON) and when it is not heated. Note that commercially available heaters include one that detects temperature using a change in impedance due to the temperature of a plastic thermistor, and one that detects temperature using a change in resistance value of a metal resistance wire. In addition, there are one that performs heating and temperature detection with one conductive wire, and another that performs heating and temperature detection with separate wires. Thus, there are various heaters, but the present invention can be applied to any heater. Even in the case of a heater that performs heating and temperature detection with a single conductor, since the heater surface temperature is detected intermittently, a short-time current flows through the conductor even when the mat 31 does not need to be heated. become. However, the temperature rise of the mat 31 due to this temperature detection is negligibly small.

  Next, the energization rate table 27 will be described. FIG. 5A is a diagram for obtaining the energization rate table 27 by experiment, and shows changes in the heater surface temperature and the surface temperature of the heat storage body 35. FIG. 5B shows the voltage applied to the heater 11. As shown in FIG. 5B, the heater 11 is applied with a pulse having an ON time B in one cycle P at a predetermined voltage, and the energization rate (duty ratio) at this time is B / P. First, an environment with the least heat dissipation and an environment with the most heat dissipation are set as product specifications. For example, the environment with the least heat dissipation is an environment where the room temperature is high and the comforter is thickest, and the environment with the highest heat dissipation is an environment where the room temperature is low and there is no comforter. The heater surface temperature Cmin at which the surface temperature of the heat storage body 35 becomes the target value T (for example, 32 ° C.) in the environment with the least heat radiation, and the surface temperature of the heat storage body 35 in the environment with the most heat radiation is the target value T. The heater surface temperature Cmax is determined by experiment. For example, the temperature difference between Cmax and Cmin is 6 ° C. The heater surface temperature Cmin is a threshold value at which the surface temperature of the heat storage body 35 does not exceed the target value T in any environment within the product specifications.

  When Cmin which is a threshold value of the heater surface temperature is acquired, as shown in FIG. 5A, the room temperature and the comforter thickness are set to predetermined conditions, and the ON time of the energization rate is set until the heater surface temperature becomes Cmin. A pulse having an initial value Bd is applied to the heater 11 (D1 period in FIG. 5). When the heater surface temperature becomes Cmin, the energization to the heater 11 is turned off for a predetermined time E (for example, 1 minute to 5 minutes), and the first temperature drop An (n is a sign of the environment. N = 1, 2, 3, ...) (1) is measured. Again, the heater 11 is energized at the energization rate of the initial value Bd until the heater surface temperature reaches Cmin, and the second temperature drop An (2) on the heater surface for a predetermined time E is measured. By repeating this, three temperature drops An (1), An (2), An (3) are measured, and the third temperature drop measurement value An (3) is the temperature drop of the current ratio table 27. The measured value An is stored (D2 period in FIG. 5). Since the final measurement value An (3) is a more stable heat dissipation state than the first measurement value An (1), the third measurement value An (3) is employed. However, an average value of a plurality of detection values may be adopted and may be measured only once.

  Thereafter, a pulse having an ON time Bn (n is an environmental code, n = 1, 2, 3,...) Such that the surface temperature of the heat storage body 35 becomes the target value T is obtained by experiments. Further, the heater surface temperature when the surface temperature of the heat storage body 35 is substantially equal to the target value T is obtained by experiments as a set value Cn (n is an environmental code, n = 1, 2, 3,...). The ON time Bn and the set value Cn are recorded corresponding to the temperature drop An of the heater surface temperature for a predetermined time E. While changing the room temperature and the thickness of the comforter, experimental data of the temperature drop An, the ON time Bn, and the set value Cn are acquired and stored in the storage circuit 23 as an energization rate table as shown in FIG. 5C. When the room temperature increases, the heat release from the heat storage body 35 decreases, and the ON time Bn, temperature drop An, and set value Cn such that the surface temperature of the heat storage body 35 reaches the target value T decrease. When the thickness of the comforter is increased, the heat release of the heat storage body 35 is reduced, and therefore, the ON time Bn, the temperature drop An, and the set value Cn such that the surface temperature of the heat storage body 35 becomes the target value T are reduced.

  Next, the operation of the thermal control circuit 22 when used by the user will be described based on the flowchart of FIG. When the main power supply (not shown) of the electric blanket 10 is turned on (step S1), the thermal control circuit 22 reads the initial value Bd of the pulse ON time B from the storage circuit 23 (step S2). The thermal control circuit 22 applies the ON time Bd to the heater 11 and heats the mat 31 until the heater surface temperature becomes Cmin (steps S3 and S4). Then, the energization to the heater 11 is turned off for a predetermined time E after the heater surface temperature reaches Cmin in the same manner as the acquisition of the temperature drop An for the predetermined time E of the heater surface temperature in the energization rate table 27 described above. The temperature drop at this time is measured three times, and the final measured value A (3) is set as the measured value A of the temperature drop in this environment (step S5).

  The thermal control circuit 22 obtains the ON time Bn and the heater surface temperature setting value Cn corresponding to the measured value A of the temperature drop from the energization rate table 27 of the storage circuit 23, and obtains the ON time B and the heater surface temperature setting value C. Obtain (step S6). If the measured value A of the temperature drop is not present in the energization rate table 27, the ON value is interpolated from the two ON times Bn corresponding to the values before and after the measured value A of the temperature drop and the two heater surface temperature set values Cn. The value of time B and the set value C of the heater surface temperature are acquired. If the heater surface temperature is lower than the set value C (Y in Step S7), the thermal control circuit 22 applies the ON time B to the heater 11 to heat the mat 31 (Step S8). If the heater surface temperature is equal to or higher than the set value C (N in step S7), the thermal control circuit 22 turns off the power supply to the heater 11 assuming that the surface temperature of the heat storage body 35 exceeds the target value T ( Step S9). Then, the thermal control circuit 22 returns to step S7 if the main power switch (not shown) of the electric blanket 10 is not turned off (N in step S10), and if the main power switch of the electric blanket 10 is turned off. (Y in step S10), the operation is terminated.

  As described above, the ON time Bn (the amount of power applied) to the heater 11 corresponding to the measured value An of the temperature drop from the predetermined temperature Cmin is obtained in advance for a plurality of environments, and this is stored as the energization rate table 27 and the thermal control circuit. 22 acquires the ON time B to the heater 11 corresponding to the detected temperature drop A from the energization rate table 27, and controls the heater 11 with heat by the acquired ON time B. Note that the above-described temperature drop is obtained by a temperature change for a predetermined time, but the temperature drop can also be obtained by a time for temperature drop from a predetermined first temperature to a predetermined second temperature.

  FIG. 7A is a diagram showing the surface temperature of the heat storage body 35 and the surface temperature of the heater 11 when the room temperature is 20 ° C., 15 ° C., and 10 ° C. The solid line is 20 ° C., the alternate long and short dash line is 15 ° C., and the alternate long and short dash line is 10 ° C. Indicates. FIG. 7B is a diagram showing the ON time Bn during one cycle P when the room temperature is 20 ° C., 15 ° C., and 10 ° C. As shown in FIG. 7A, the surface temperature of the heat storage body 35 converges to the same target value T for all the room temperatures of 20 ° C., 15 ° C., and 10 ° C. The temperature of the surface of the heater 11 at the time of convergence becomes lower in the order of 20 ° C., 15 ° C., and 10 ° C. because the amount of heat radiation increases as the room temperature decreases. The measured value An of the temperature drop for a predetermined time E from the predetermined temperature Cmin decreases in the order of 20 ° C., 15 ° C., and 10 ° C. in room temperature. Accordingly, if the pulse ON time is 20 ° C., 15 ° C., and 10 ° C., respectively B1, B2, and B3, B1 <B2 <B3, and the lower the room temperature, the greater the amount of heating to the heater 11. Note that the voltage and pulse period are the same P for all of 20 ° C., 15 ° C. and 10 ° C. Thus, since the mat 31 is heated with the ON time Bn corresponding to the temperature drop measurement value An, the surface temperature of the heat storage body 35 can converge to the same target value T even if the room temperature is different.

  FIG. 8A is a diagram showing the surface temperature of the heat storage body 35 and the surface temperature of the heater 11 in a thick comforter and a thin comforter, where the solid line indicates a thick comforter and the broken line indicates a thin comforter. FIG. 8B is a diagram showing the ON time Bn during one cycle P of the thick comforter and the thin comforter. As shown in FIG. 8A, the surface temperature of the heat storage body 35 converges to the same target value T for both the thick comforter and the thin comforter. The temperature of the surface of the heater 11 at the time of convergence becomes lower in the order of thicker comforters and thinner comforters because the amount of heat release increases as the comforter thickness decreases. And the measured value An of the temperature drop from the predetermined time E from the predetermined temperature Cmin becomes lower in order of the thick comforter and the thinner comforter. Therefore, the pulse ON time is B4 <B5 when the thick comforter and the thin comforter are B4 and B5, respectively, and the heating amount to the heater 11 increases as the comforter is thinner. Note that the voltage and pulse period are the same P for both the thick comforter and the thin comforter. As described above, since the mat 31 is heated for the ON time Bn corresponding to the temperature increase value An, the surface temperature of the heat storage body 35 can converge to the same target value T even if the thickness of the comforter is different.

  Further, as shown in step S7 and step S9 in FIG. 6, the thermal control circuit 22 determines that the surface temperature of the heat storage body 35 becomes the target value T when the heater surface temperature becomes equal to or higher than the set value Cn based on the energization rate table 27. As a result, the power supply to the heater 11 is turned off. Thereby, it is possible to prevent the heat storage body surface temperature from becoming high in an abnormal state and causing the user to get a low temperature burn without detecting the temperature of the mat of the heat storage body. For example, an environmental change in which a comforter is added during the period T2 heated by Bn in FIG. 5A, an accident in which the electric blanket 10 breaks down due to a fallen object, or an electric blanket 10 for heating the mat 31 Low temperature burns can be prevented from misuse, such as hanging on the body as a conventional electric blanket. The thermal control circuit 22 turns off the energization to the heater 11 when the heater surface temperature exceeds the set value Cn. However, the thermal control circuit 22 turns off the energization to the heater 11 when the heater surface temperature exceeds the set value Cn. It may be.

  As described above, the present invention measures the temperature drop for a predetermined time using a conventional heater with temperature detection without detecting the temperature of the mat, and controls the temperature of the heater based on the temperature drop. The temperature is adjusted. For this reason, there is no need to add a new sensor to detect the temperature of the mat or the accompanying parts such as circuits, and only the control software is changed without changing the hardware configuration of the existing electric blanket. By doing so, the electric blanket can be used to keep the mat of the heat storage body warm. Further, since the present invention does not detect the temperature of the mat, the mat of the heat storage body and the heater can be separated. Thereby, it becomes easy to remove the dirt on the mat, dry the sweat, or replace the mat.

  In addition, although the room temperature sensor 24 as an existing electric blanket can detect room temperature, it cannot detect the temperature change accompanying ON / OFF of the heater 11. FIG. Therefore, since the room temperature sensor 24 cannot be used as a means for detecting an electric blanket corresponding to a change in the heat radiation environment other than the room temperature, for example, a temperature change on the surface of the heat storage body 35 due to a difference in the thickness of the comforter, the present invention is not limited to the room temperature. The present invention can also be applied to an existing electric blanket without the sensor 24. However, if a plurality of the energization rate tables in FIG. 5C are acquired and stored for each room temperature, and the energization rate table is selected according to the temperature detected by the room temperature sensor 24, the accuracy of thermal control is improved with respect to temperature changes. It is also possible to cope with changes in the heat radiation environment other than room temperature.

  Further, the temperature change accompanying the ON / OFF of the heater 11 of the electric blanket is performed by directly detecting the temperature of the heater. However, the room temperature sensor of the existing electric blanket is disposed at a position covered with the mat. Therefore, if it is possible to detect a temperature change accompanying ON / OFF of the heater 11, a temperature change accompanying ON / OFF of the heater 11 can be detected by a room temperature sensor instead of the heater 11. Furthermore, when the temperature detection of the existing electric blanket is provided with a temperature detection means separate from the heater and the room temperature sensor, the temperature of the blanket of the electric blanket is detected and the temperature of the heater is controlled. By detecting the temperature drop by the detecting means, the present invention can be applied to this electric blanket.

  Further, as described above, an energization rate table is acquired in advance from experimental data, and thermal control is performed based on the energization table, so that the error in the mat surface temperature can be further reduced.

  Further, the present invention measures a temperature drop from a predetermined temperature, and the predetermined temperature is a heater surface temperature Cmin at which the surface temperature of the heat storage body in the environment with the least heat dissipation in the environment within the product specifications becomes a target value. Therefore, the surface temperature of the heat storage body does not exceed the target value T, and for example, low temperature burns can be prevented. And it can heat with an initial stage electric charge rate until the surface temperature of a thermal storage body does not exceed target value T. For this reason, by increasing the initial charging rate, the surface temperature of the heat storage body can be quickly raised while preventing low-temperature burns. Even if the predetermined temperature is not Cmin, low temperature burns can be prevented if it is Cmin or less.

DESCRIPTION OF SYMBOLS 10 ... Electric blanket 11 ... Heater 12 ... 1st blanket fabric 13 ... 2nd blanket fabric 14 ... Controller 15 ... Core wire 16 ... Primary conductor 17 ... Plastic thermistor 18 ... Secondary conductor 19 ... Outer sheath 20 ... Switch 21 ... Temperature detection circuit 22 ... Thermal control circuit 23 ... Memory circuit 24 ... Room temperature sensor 27 ... Electricity rate table 30 ... Mattress 31 ... Mat 32 ... Human body 33 ... Comforter 34 ... Bag body 35 ... Heat storage body

Claims (7)

An electric blanket having a heater and heating a laid mat,
A temperature detection circuit for detecting a temperature at a predetermined location of the electric blanket, a storage means for storing a temperature drop from the predetermined temperature at the predetermined location and a table of the amount of electricity applied to the heater corresponding to the temperature drop; When the temperature rise at the predetermined place during heating to the heater reaches the predetermined temperature, the heating to the heater is cut off, and the temperature drop at the predetermined place is detected by the temperature detection circuit and detected. An electric blanket comprising a thermal control circuit that acquires an applied amount of electricity to the heater corresponding to the temperature drop from the table of the storage means, and controls the temperature of the heater with the acquired applied amount of electricity.   2. The electric blanket according to claim 1, wherein the predetermined temperature is a set temperature for thermal control in an environment where the amount of heat radiation is the smallest in a set heat radiation environment.   The electric blanket according to claim 1, wherein the thermal control circuit detects the temperature drop a plurality of times.   The electric blanket according to claim 1, wherein the mat is a bedding.   2. The electric blanket according to claim 1, wherein the thermal control circuit performs thermal control by changing an energization rate, and the applied amount stored in the table is an energization rate at a constant voltage.   The storage means stores a set value of the temperature at the predetermined location corresponding to the temperature increase in the table, and the thermal control circuit stores the set value corresponding to the detected temperature increase in the table of the storage means. 2. The electricity according to claim 1, wherein the heater is turned off when the temperature of the predetermined location exceeds the acquired set value or becomes equal to or higher than the acquired set value. blanket.   The electric blanket according to claim 1, wherein the heater has a conductive wire for heating the mat and detecting the temperature.

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