PTC heating device

Abstract

To provide a PTC heating device capable of efficiently heating even when the wind speed and the surrounding temperature are low. [Solution] One aspect of the present invention is a PTC heating device including a PTC heater block configured by stacking N (N is an integer greater than or equal to 3) heat dissipation fins and N-1 PTC heating components alternately one by one, and the N-1 PTC heating components are configured to operate as a whole in a temperature range above the temperature showing the minimum resistance value in the PTC temperature-resistance characteristics and below the Curie point over the entire temperature range of air sent to the PTC heater block from negative to room temperature in degrees Celsius.

Description

[Technical field]

[0001] The present invention relates to a PTC heating device having a PTC heating element and heat dissipation fins. [Background technology]

[0002] Heating devices using PTC (Positive Temperature Coefficient) heating elements can easily control temperature and reduce power consumption by utilizing the positive temperature characteristics of the PTC heating element. In a PTC heating device, a pair of heat dissipation fins are provided to sandwich the PTC heating element, and the heat generated by the PTC heating element is effectively dissipated to the outside from the heat dissipation fins.

[0003] Patent Document 1 discloses a PTC unit for vehicle heaters, which includes a heat generating part including a PTC element, and a heat dissipating part provided on at least one surface of the heat generating part, which includes a heat dissipating substrate and a heat dissipating coating provided on at least a part of the outer surface of the heat dissipating substrate to improve heat dissipation performance. Patent Documents 2 and 3 disclose a PTC heater structure in which multiple PTC elements and multiple heat dissipating fins are stacked. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2019-509940 [Patent Document 2] International Publication No. 2014 / 069270 [Patent Document 3] JP 2007-157528 A Summary of the Invention [Problem to be solved by the invention]

[0005] When using a blower (fan) to blow air into a PTC heater block that combines a PTC heating element and heat dissipation fins, if the air temperature (ambient temperature) is low, it will operate at a temperature significantly lower than the Curie temperature of the PTC heating element. For this reason, for example, when heating a small space (such as the foot space in a vehicle), where a high wind speed is not required, it will not be able to heat sufficiently, and it will also be driven in a low resistance state, resulting in unnecessary power consumption.

[0006] An object of the present invention is to provide a PTC heating device that can efficiently heat even when the wind speed and the ambient temperature are low. [Means for solving the problem]

[0007] One aspect of the present invention is a PTC heating device including a PTC heater block configured by stacking N (N is an integer greater than or equal to 3) heat dissipation fins and N-1 PTC heating components alternately one by one, and the N-1 PTC heating components are configured to operate as a whole in a temperature range above the temperature showing the minimum resistance value in the PTC temperature-resistance characteristics and below the Curie point over the entire temperature range of air sent to the PTC heater block from negative to room temperature in degrees Celsius.

[0008] With this configuration, over the entire temperature range of the air sent to the PTC heater block from negative to room temperature in Celsius, all of the N-1 PTC heat generating components operate in a temperature range above the temperature showing the minimum resistance value in the PTC temperature-resistance characteristics and below the Curie point, i.e., in the range of positive temperature characteristics, and even when the ambient temperature is low, heat can be actively stored in the heat dissipation fins to obtain sufficient heat generation.

[0009] In the above PTC heating device, the N-1 PTC heating components may be configured to operate as a whole in a temperature range from the temperature showing the minimum resistance value in the PTC temperature-resistance characteristic to the Curie point when the wind speed of the air sent to the PTC heater block is in the range of 3.5 m / s or less. This allows all of the N-1 PTC heating components to operate in the range of the positive temperature characteristic even when the ambient temperature is low and the wind speed of the air sent to the PTC heater block is relatively low at 3.5 m / s or less, and a sufficient amount of heat can be obtained by utilizing the heat storage effect in the heat dissipation fins due to the low wind speed.

[0010] The PTC heating device may further include a temperature sensor that detects the temperature near the PTC heater block, and a control unit that controls the rotation of the rotor based on the temperature detected by the temperature sensor, and the control unit may be configured to control the rotation speed of the rotor to a second rotation speed higher than the first rotation speed when the temperature detected by the temperature sensor exceeds a preset temperature while the rotation speed of the rotor is controlled to a first rotation speed. In this way, the amount of heat generated by the PTC heater block HB is controlled by the rotation speed of the rotor.

[0011] The above PTC heating device may further include a blower having a rotor for blowing air to the PTC heater block, and the outer dimensions of the PTC heater block may be set to be the same size as a circumscribed rectangle of the rotor. This allows the air blown from the rotor of the blower to be effectively blown to the PTC heater block. In this case, the blower may be connected to face the PTC heater block. This realizes a device configuration in which the PTC heater block and the blower are integrated. Effect of the Invention

[0012] According to the present invention, it is possible to provide a PTC heating device that can efficiently heat even when the wind speed and the ambient temperature are low. [Brief description of the drawings]

[0013] [Figure 1]1 is a perspective view illustrating a configuration of a PTC heating device according to an embodiment of the present invention. [Diagram 2] FIG. 1 is an exploded perspective view illustrating the configuration of a PTC heating device according to an embodiment of the present invention. [Diagram 3] 1 is a cross-sectional view illustrating the configuration of a PTC heating device according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating the temperature-resistance characteristics of a PTC heat generating component. [Diagram 5] FIG. 5 is an enlarged view of the temperature-resistance characteristics of FIG. [Figure 6] FIG. 2 is a perspective view illustrating the configuration of a reference PTC heating device. [Figure 7] FIG. 2 is a schematic diagram illustrating a method for measuring heating characteristics. [Figure 8] 13(a) and (b) are diagrams showing heating characteristics when the wind speed is 0.5 m / s. [Figure 9] 13(a) and (b) are diagrams showing heating characteristics when the wind speed is 1.5 m / s. [Figure 10] 13(a) and (b) are diagrams showing the relationship between heating characteristics and room temperature. [Figure 11] 11A to 11C are diagrams illustrating heating characteristics according to differences in configuration. [Figure 12] 11A to 11C are diagrams illustrating heating characteristics according to differences in configuration. [Figure 13] 11A to 11C are diagrams illustrating heating characteristics according to differences in configuration. [Figure 14] 5 is a schematic diagram for explaining the control of the PTC heating device according to the present embodiment. FIG. [Figure 15] FIG. 11 is a perspective view showing an example in which a PTC heater block and a blower are integrated together. [Figure 16] 11 is a diagram showing the relationship between the distance between a PTC heater block and a blower and the temperature of the blower. FIG. [Figure 17] 11 is a diagram showing the relationship between the distance between a PTC heater block and a blower and the temperature of the blower. FIG. [Figure 18] 11 is a diagram showing the relationship between the distance between a PTC heater block and a blower and the temperature of the blower. FIG. [Figure 19]13 is a perspective view illustrating a PTC heating device according to another embodiment. FIG. [Figure 20] 13 is a perspective view illustrating a PTC heating device according to another embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same members are designated by the same reference numerals, and the description of members that have already been described will be omitted as appropriate.

[0015] (Configuration of PTC heating device) FIG. 1 is a perspective view illustrating the configuration of a PTC heating device according to the present embodiment. FIG. 2 is an exploded perspective view illustrating the configuration of the PTC heating device according to the present embodiment. FIG. 3 is a cross-sectional view illustrating the configuration of the PTC heating device according to the present embodiment. The PTC heating device 1 according to this embodiment is a device that generates heat by applying a voltage. The PTC heating device 1 includes a PTC heater block HB that is configured by stacking N (N is an integer of 3 or more) heat dissipation fins and N-1 PTC heating members one by one in an alternating manner. In this embodiment, the case of N=4 will be described as an example, but the experimental results described later also include examples other than N=4.

[0016] The PTC heating device 1 shown in FIGS. 1 to 3 has a PTC heater block HB in which a first heater module HM1, a central PTC heating member 30, and a second heater module HM2 are laminated in this order.

[0017] In this embodiment, for convenience of explanation, the direction in which the first heater module HM1, the central PTC heat generating member 30, and the second heater module HM2 are stacked is called the first direction D1, the direction in which the first heater module HM1 and the second heater module HM2 extend perpendicular to the first direction D1 is called the second direction D2, and the direction perpendicular to the first direction D1 and the second direction D2 is called the third direction D3. The first direction D1 is also called the thickness (or stacking) direction, the second direction D2 is also called the length direction, and the third direction D3 is also called the width direction. Here, in FIG. 2, the insulating resin 17 described later is indicated by a two-dot chain line. Also, FIG. 3 is a cross-sectional view of the PTC heat generating device 1 cut along a plane parallel to the first direction D1 and the third direction D3.

[0018] (Configuration of the first heater module) The first heater module HM1 has a first PTC heat generating member 10, a pair of electrode parts 13, and a pair of first heat dissipation fins 15. That is, the first heater module HM1 has a configuration in which the first PTC heat generating member 10 is sandwiched between the pair of electrode parts 13 and the pair of first heat dissipation fins 15.

[0019] The first PTC heat generating member 10 has a PTC element 11 and electrode layers 12 provided on the front and back of the PTC element 11. The PTC element 11 has a positive temperature characteristic. That is, when the temperature reaches or exceeds the Curie point, the resistance increases, limiting any further temperature increase. By using the PTC element 11, it is possible to facilitate temperature control and reduce power consumption. In this embodiment, a plurality of (for example, two) PTC elements 11 are arranged in parallel in the second direction D2 (length direction), but one or three or more may be arranged in parallel. In addition, a plurality of PTC elements 11 may be arranged in parallel in the third direction D3 (width direction).

[0020] Metals such as silver (Ag) and aluminum (Al) are used as materials for the electrode layers 12 provided on the front and back sides of the PTC element 11. The electrode layers 12 are formed by, for example, spraying these metals onto the front and back sides of the PTC element 11. The surface of the electrode layer 12 formed by spraying the metal has minute projections and recesses. The electrode layer 12 is in ohmic contact with the PTC element 11.

[0021] The pair of electrode units 13 sandwich the first PTC heat generating member 10 therebetween and are electrically connected to the front and rear electrode layers 12. In this embodiment, plate-like members 151 are provided to sandwich the outer sides of the first heat dissipation fins 15 in the first direction D1, and one of the plate-like members 151 (the one on the first PTC heat generating member 10 side) is used as the electrode unit 13.

[0022] The electrode portion 13 and the first heat dissipation fin 15 are made of, for example, stainless steel or aluminum. The first heat dissipation fin 15 is formed by bending a plate material made of, for example, aluminum so that peaks and valleys are repeated. The pair of first heat dissipation fins 15 are provided, for example, to have the same size and have the same thermal resistance. The first heat dissipation fin 15 is electrically connected to the electrode portion 13, so that the first heat dissipation fin 15 can be used as a conductive path for applying a voltage to the PTC element 11. For example, a voltage is applied to the PTC element 11 with one side of the pair of first heat dissipation fins 15 as a positive electrode and the other side as a negative electrode.

[0023] The electrode portion 13 (or the plate-like member 151 used as the electrode portion 13) is connected to the first PTC heat generating member 10 by, for example, a heat-resistant adhesive having electrical conductivity (such as a conductive silicone adhesive). An extension portion 152 is provided on the plate-like member 151 of the first heat dissipation fin 15, and a cable (not shown) for applying voltage is connected to this extension portion 152. As a result, a predetermined voltage is applied from the cable to the first PTC heat generating member 10 via the plate-like member 151 and the first heat dissipation fin 15.

[0024] The periphery (excluding the surfaces of the electrode layers 12 on the front and back) of the first PTC heat generating component 10 sandwiched between the pair of first heat dissipation fins 15 is covered with insulating resin 17. This insulating resin 17 can prevent dust from entering between the pair of first heat dissipation fins 15, prevent moisture from entering the first PTC heat generating component 10, prevent the side surfaces of the first PTC heat generating component 10 from being exposed, and prevent the pair of first heat dissipation fins 15 from being crushed (mechanical reinforcement).

[0025] Of the pair of first heat dissipation fins 15, the first heat dissipation fin 15 on the side of the central PTC heat generating component 30 is connected to the central PTC heat generating component 30 by, for example, a heat-resistant adhesive having electrical conductivity (conductive silicone adhesive or the like). As a result, the first heat dissipation fin 15 on the side of the central PTC heat generating component 30 of the pair of first heat dissipation fins 15 is electrically connected to one of the electrode layers 32 on the front and back of the central PTC heat generating component 30.

[0026] (Configuration of the second heater module) The second heater module HM2 has the same configuration as the first heater module HM1. That is, the second heater module HM2 has a second PTC heat generating member 20, a pair of electrode parts 23, and a pair of second heat dissipation fins 25. Here, the second PTC heat generating member 20 is the same as the first PTC heat generating member 10, the PTC element 21 is the same as the PTC element 11, and the electrode layer 22 is the same as the electrode layer 12. In addition, the pair of electrode parts 23 is the same as the pair of electrode parts 13, and the pair of second heat dissipation fins 25 is the same as the pair of first heat dissipation fins 15. Furthermore, the plate-shaped member 251 is the same as the plate-shaped member 151, and the extension part 252 is the same as the extension part 152. The second heat dissipation fin 25 on the side of the central PTC heat generating member 30 of the pair of second heat dissipation fins 25 is electrically connected to the other of the electrode layers 32 on the front and back of the central PTC heat generating member 30.

[0027] (Structure of central PTC heating element) The central PTC heat generating component 30 has a PTC element 31 and electrode layers 32 provided on the front and back of the PTC element 31. The PTC element 31 is similar to the PTC element 11 and the PTC element 21. In this embodiment, a plurality of (for example, two) PTC elements 31 are arranged side by side in the second direction D2 (length direction), but one or three or more PTC elements may be arranged side by side. Also, a plurality of PTC elements 31 may be arranged side by side in the third direction D3 (width direction). The periphery of the central PTC heat generating component 30 (excluding the surfaces of the electrode layers 32 on the front and back) is covered with an insulating resin 17.

[0028] Electrode portions 33 are provided between one of the electrode layers 32 of the central PTC heat generating component 30 and the first heat dissipation fin 15, and between the other of the electrode layers 32 of the central PTC heat generating component 30 and the second heat dissipation fin 25. That is, the pair of electrode portions 33 sandwich the central PTC heat generating component 30 therebetween and are electrically connected to the electrode layers 32 on the front and back, respectively.

[0029] In this embodiment, the plate-like member 151 on the central PTC heat generating member 30 side of the first heat dissipating fins 15 on the central PTC heat generating member 30 side of the pair of first heat dissipating fins 15 is used as the electrode portion 33. Also, the plate-like member 251 on the central PTC heat generating member 30 side of the second heat dissipating fins 25 on the central PTC heat generating member 30 side of the pair of second heat dissipating fins 25 is used as the electrode portion 33.

[0030] The electrode portion 33 (or the plate-like members 151, 251 used as the electrode portion 33) is connected to the central PTC heat generating member 30 by, for example, a heat-resistant adhesive having electrical conductivity (such as a conductive silicone adhesive).

[0031] The first heat dissipation fin 15 is conductive with the electrode portion 33 on one side of the front or back, and the second heat dissipation fin 25 is conductive with the electrode portion 33 on the other side of the front or back, so that the first heat dissipation fin 15 and the second heat dissipation fin 25 can be used as a conductive path for applying voltage to the central PTC heat generating member 30.

[0032] In the PTC heater block HB of the PTC heating device 1 according to this embodiment, four heat dissipating fins (a pair of first heat dissipating fins 15 and a pair of second heat dissipating fins 25) and three PTC heating members (the first PTC heating member 10, the central PTC heating member 30, and the second PTC heating member 20) are alternately stacked one by one in the first direction D1. With this configuration, two adjacent PTC heating members share one heat dissipating fin provided between them. For example, the first heat dissipating fin 15 arranged between the first PTC heating member 10 and the central PTC heating member 30 is shared by the first PTC heating member 10 and the central PTC heating member 30. In addition, the second heat dissipating fin 25 arranged between the second PTC heating member 20 and the central PTC heating member 30 is shared by the second PTC heating member 20 and the central PTC heating member 30.

[0033] In addition, since the four heat dissipation fins (a pair of first heat dissipation fins 15 and a pair of second heat dissipation fins 25) are used as a conductive path for applying a voltage to each PTC element, the polarity of the voltage applied to each of the four heat dissipation fins is in the order of positive, negative, positive, negative (or the reverse order). An example of the size of the heater block HB of the PTC heating device 1 is about 3 cm to about 5 cm in thickness, about 3 cm to about 5 cm in length, and about 2 cm in width.

[0034] In the PTC heating device 1 according to this embodiment, the first PTC heating member 10, the second PTC heating member 20, and the central PTC heating member 30 are configured to operate in a temperature range between the minimum resistance value in the PTC temperature-resistance characteristic and the Curie point as a whole, in the entire temperature range of the air sent to the PTC heater block HB from negative to room temperature in Celsius. In other words, the heater block HB operates in the positive temperature characteristic range in the temperature range including negative Celsius. As a result, even when the ambient temperature is low, the heater block HB operates in the positive temperature characteristic range, and a sufficient amount of heat can be obtained by actively storing heat in the heat dissipation fins.

[0035] FIG. 4 is a diagram illustrating the temperature-resistance characteristics of a PTC heat generating component. FIG. 5 is an enlarged view of the temperature-resistance characteristics of FIG. The ambient temperature on the horizontal axis of the temperature-resistance characteristics shown in Figures 4 and 5 is the temperature in a windless state inside the thermostatic chamber containing the PTC heat generating component. In this temperature-resistance characteristic, the temperature inside the thermostatic chamber in a windless state is regarded as the temperature of the PTC heat generating component. As shown in Figures 4 and 5, the PTC heating component has the characteristic that its resistance value rises sharply near the Curie point Tc. Here, the Curie point Tc is the temperature at which the resistance value R25 at room temperature (25°C) doubles. The Curie point Tc is set by changing the compounding ratio of, for example, lead (Pb), titanium (Ti), barium (Ba), etc., when mixing the materials of the PTC heating element. Once set, the Curie point Tc does not change over time.

[0036] As shown in FIG. 5, the change in resistance from room temperature to the Curie point Tc tends to drop from the resistance value R25 at room temperature to the minimum resistance value Rmin, and then tends to increase from the minimum resistance value Rmin toward the Curie point Tc.

[0037] In the PTC heating device 1 of this embodiment, the first PTC heating member 10, the second PTC heating member 20 and the central PTC heating member 30 as a whole are configured to operate in a temperature range (characteristic temperature range) above the temperature Tm indicating the minimum resistance value Rmin and below the Curie point Tc, over the entire temperature range from negative to room temperature in Celsius, of the air sent to the PTC heater block HB.

[0038] (Standard PTC heating device) Next, a reference PTC heating device that serves as a comparative example for the PTC heating device 1 according to this embodiment will be described. FIG. 6 is a perspective view illustrating the configuration of a standard PTC heating device. The reference PTC heating device 100 is configured by directly connecting the first heater module HM1 and the second heater module HM2 without providing the central PTC heating member 30 of the PTC heater block HB of the PTC heating device 1 according to this embodiment. That is, in the reference PTC heating device 100, a pair of first heat dissipation fins 15 are provided between the first PTC heating member 10, and a pair of second heat dissipation fins 25 are provided between the second PTC heating member 20, so that the first PTC heating member 10 and the second PTC heating member 20 do not share heat dissipation fins.

[0039] The PTC heating device 1 having three PTC heating members has a higher absolute output than the reference PTC heating device 100 having two PTC heating members. However, in the PTC heating device 1 according to this embodiment, two adjacent PTC heating members share one heat dissipation fin provided between them, so the heat dissipation efficiency of the shared heat dissipation fin is lower than that of the reference PTC heating device 100 having the same number of heat dissipation fins.

[0040] Here, if the heat dissipation efficiency of the heat dissipation fins in the PTC heating device 1 is sufficiently increased (if heat dissipation fins with sufficiently low thermal resistance are used), the temperature characteristics with respect to the wind speed will be equivalent between the PTC heating device 1 and the reference PTC heating device 100 even if the number of PTC heating members is different. However, in this embodiment, a configuration in which the heat dissipation fins are shared is adopted to reduce the heat dissipation efficiency. Specifically, in the PTC heating device 1 and the reference PTC heating device 100, the thermal resistance of each of the four heat dissipation fins is equivalent, but in the PTC heating device 1, the heat dissipation fin between two adjacent PTC heating members is shared. As a result, the PTC heating device 1 is configured to promote the accumulation of heat in the heat dissipation fins compared to a configuration in which the heat dissipation fins are not shared, and to operate in a temperature range of the PTC heating members as a whole, above the temperature Tm indicating the minimum resistance value Rmin and below the Curie point Tc, even when the ambient temperature is low. By utilizing this configuration, the PTC heating device 1 achieves a higher reaching temperature than the reference PTC heating device 100 even at a low ambient temperature and with the same wind speed.

[0041] On the other hand, in the reference PTC heating device 100, when the ambient temperature is low, at least one of the first PTC heating member 10 and the second PTC heating member 20 operates in a temperature range significantly lower than the Curie point Tc. As shown in Fig. 5, if the temperature is lower than the Curie point Tc and the temperature is in the range from the resistance value R25 to the minimum resistance value Rmin (range of negative temperature characteristics), a phenomenon occurs in which the resistance value increases as the ambient temperature decreases (phenomenon due to negative temperature characteristics), which further reduces the heating temperature, which further increases the resistance value, creating a vicious cycle.

[0042] In the PTC heating device 1 of this embodiment, the first PTC heating member 10, the second PTC heating member 20 and the central PTC heating member 30 as a whole are configured to operate in a temperature range above the temperature Tm indicating the minimum resistance value Rmin and below the Curie point Tc, over the entire temperature range of the air sent to the PTC heater block HB from negative to room temperature in Celsius.

[0043] Furthermore, the PTC heating device 1 according to this embodiment has one more PTC heating component than the reference PTC heating device 100, and shares one heat dissipation fin between two adjacent PTC heating components, thereby making active use of heat accumulation in the heat dissipation fin (sharing reduces the heat dissipation efficiency of the heat dissipation fin and causes heat accumulation).With these configurations, the PTC heating device 1 can provide sufficient heating even at low ambient temperatures, and since it operates in a temperature range with a relatively high resistance value compared to the reference PTC heating device 100, it is possible to reduce power consumption.

[0044] Here, whether the first PTC heat generating member 10, the second PTC heat generating member 20, and the central PTC heat generating member 30 as a whole are operating in a temperature range above the temperature Tm showing the minimum resistance value Rmin and below the Curie point Tc can be grasped by changing the temperature of the air sent to the PTC heater block HB and changing the amount of current (resistance value) when electricity is passed through the PTC heater block HB. For example, when the temperature of the air sent to the PTC heater block HB is raised from negative to room temperature in Celsius, if the amount of current flowing through the entire PTC heater block HB decreases (resistance value increases) within that range, it means that they are operating in a temperature range showing a positive temperature characteristic.

[0045] (Heating characteristics) Next, the heating characteristics of the PTC heating device 1 according to this embodiment will be described. FIG. 7 is a schematic diagram illustrating a method for measuring the heating characteristics. 7, a box 210 connected to a duct 200 is prepared, the PTC heating device 1 and a blower 50 are placed inside the duct 200, and air is sent from the blower 50 to the PTC heating device 1. Then, while the PTC heating device 1 is energized to generate heat, the temperature reached at a predetermined position of the box 210 is measured.

[0046] The dimensions of the box 210 are 395 mm in length, 392 mm in width, and 443 mm in depth (height). The dimensions of the duct 200 are 50 mm in length, 500 mm in width, and 345 mm in length. The front dimensions of the blower 50 are 50 mm x 50 mm. The duct 200 is connected to the lower side (near the bottom) of the side wall of the box 210, and heated air is sent into the box 210 from an opening (air outlet) at the connection position of the duct 200.

[0047] The temperature was measured at four locations within the box 210: positions A, B, C, and D. Position A is the air outlet of the PTC heating device 1. Position B is the bottom center of the box 210. Position C is the center of the box 210. Position D is the ceiling center of the box 210. The horizontal distance from the air outlet to positions B, C, and D is approximately 20 cm. The heightwise distance between positions B and C, and the heightwise distance between positions C and D, are each approximately 20 cm.

[0048] The temperature inside the box body 210 was set to 20°C, the PTC heating device 1 was made to generate heat, and air was sent from the blower 50 to the PTC heating device 1 at a predetermined wind speed, and the temperatures reached at positions A, B, C and D were measured every minute from 0 minutes to 5 minutes.

[0049] Figures 8(a) and (b) are diagrams showing heating characteristics when the wind speed is 0.5 m / s. Figures 9(a) and (b) are diagrams showing heating characteristics when the wind speed is 1.0 m / s. In each of Figures 8 and 9, (a) shows the reached temperature versus time, and (b) shows the output versus time. The heating characteristics shown in Figures 8 and 9 are the characteristics of a PTC heating device 1 equipped with two PTC heating components (N=3).

[0050] As shown in Figure 8(a), when the wind speed is 0.5 m / s, the temperature reached at position A is the highest and the temperature reached at position B is the lowest. The temperatures reached at positions C and D are slightly higher than the temperature reached at position B.

[0051] As shown in Fig. 9(a), when the wind speed is 1.0 m / s, similar to when the wind speed is 0.5 m / s, the reached temperature is the highest at position A and the lowest at position B. The reached temperatures at positions C and D are lower than those at position A and higher than those at position B, but the reached temperature at position C is higher than that at position D.

[0052] Comparing the outputs in Figure 8(b) and Figure 9(b), the output in the case of a wind speed of 0.5 m / s shown in Figure 8(b) decreases over time, but the output in the case of a wind speed of 1.0 m / s shown in Figure 9(b) does not change much. In other words, the lower the wind speed, the lower the output tends to be.

[0053] For example, when heating a narrow space such as the foot space in a car, it is sufficient to heat the space at a distance of several tens of centimeters from the hot air outlet. As shown in FIG. 7, the temperature around positions C and D (around the pedal position at the feet) is sufficient. As shown in FIG. 8(a) and FIG. 9(a), positions C and D reach 30°C in a few minutes. On the other hand, the output is lower at a wind speed of 0.5 m / s. In other words, with the PTC heating device 1 according to this embodiment, a sufficient heating temperature can be obtained even with a low wind speed, and the output required for this can be low. This is because the heat storage effect in the heat dissipation fins is effectively utilized.

[0054] 10(a) and (b) are diagrams showing the relationship between the heating characteristics and room temperature. FIG. 10(a) shows the relationship between room temperature (ambient temperature) and outlet temperature (achieved temperature), and FIG. 10(b) shows the relationship between the reached temperature and output. The heating characteristics shown in FIG. 10 are the characteristics of a PTC heating device 1 equipped with three PTC heating components (N=4). Here, the ambient temperature is changed from -20°C to +20°C in 5°C increments, and air is blown at a volume of 10 m from the duct 200 shown in FIG. 7 toward the heater block HB. 3 The temperature reached and output at position A were measured when air was sent at a speed of 2.0 m / s and heated for 3 minutes.

[0055] In the PTC heating device 1 according to this embodiment, the PTC heating components are set to operate in a temperature range from the temperature Tm at which the minimum resistance value Rmin is shown to the Curie point Tc or lower in the entire ambient temperature range from negative to room temperature in Celsius. Therefore, even if the ambient temperature is, for example, -20°C, it is possible to obtain a temperature exceeding 60°C.

[0056] Here, if the PTC heating elements as a whole operate in a range of negative temperature characteristics when the ambient temperature is low, sufficient heating characteristics cannot be obtained. For example, when the ambient temperature is low enough to be negative in Celsius, if the PTC heating elements operate in a region of negative temperature characteristics (a region in which the resistance value at room temperature drops to the minimum resistance value Rmin as shown in Figure 5), the resistance value increases with the decrease in temperature, and sufficient heating characteristics cannot be obtained.

[0057] In this embodiment, even when the ambient temperature is negative in Celsius, the PTC heating members as a whole are configured to operate in a temperature range of not less than the temperature Tm indicating the minimum resistance value Rmin and not more than the Curie point Tc, so that the resistance value decreases with a decrease in temperature, and sufficient heating characteristics can be obtained. For example, the PTC heating device 1 according to this embodiment is configured to operate in a temperature range of not less than the temperature Tm indicating the minimum resistance value Rmin and not more than the Curie point Tc, even when the ambient temperature is about -50°C. As a result, sufficient heating characteristics can be obtained even at low temperatures. Moreover, the temperature range includes the temperature range in which the device is operated at a resistance value higher than the resistance value R25 at room temperature, so that power consumption can be reduced.

[0058] (Heating characteristics due to differences in composition) 11 to 13 are diagrams illustrating heating characteristics resulting from differences in configuration. 11 to 13 show the relationship between the wind speed of the blower 50 and the temperature reached. Each figure shows the relationship when the temperature of the air sent by the blower 50 is set as a parameter of -25°C, 0°C, and 25°C. Here, air is sent from the duct 200 shown in Fig. 7 toward the heater block HB at wind speeds of 1.0 m / s, 2.0 m / s, 3.0 m / s, and 4.0 m / s, and the temperature reached at position A after heating for 3 minutes is measured.

[0059] Figure 11 shows the characteristics of a PTC heating device equipped with two PTC heating elements (N=3) and a heater block HB that is 40 mm long, 40 mm high, and 15 mm wide. Figure 12 shows the characteristics of a PTC heating device equipped with three PTC heating elements (N=4) and a heater block HB that is 40 mm long, 40 mm high, and 15 mm wide. Figure 13 shows the characteristics of a PTC heating device equipped with three PTC heating elements (N=4) and a heater block HB that is 40 mm long, 40 mm high, and 24 mm wide.

[0060] As shown in Figures 11 to 13, it can be seen that the greater the number of PTC heat generating components, the higher the ultimate temperature can be obtained at any temperature and wind speed. Also, as shown in Figures 12 and 13, it can be seen that even with the same number of PTC heat generating components, a heater block HB with a narrower width achieves a higher ultimate temperature at relatively low temperatures such as 0° and -25° and in areas with low wind speeds (2.0 m / s or less). This is because the narrower the width, the lower the heat dissipation efficiency of the heat dissipation fins, and heat accumulates in the heat dissipation fins.

[0061] In a ceramic fan heater using a conventional PTC heating device (reference PTC heating device 100), the wind speed of the air sent to the heater is relatively high because it is necessary to heat a large space such as a room. If a conventional PTC heating device is used in an appliance used under such high wind speed conditions, the PTC heating component will operate in the negative temperature characteristic range when the temperature reaches the negative temperature range, and sufficient temperature characteristics cannot be obtained.

[0062] In order to solve the problem of the negative temperature characteristic, in this embodiment, a central PTC heat generating member 30 is added (a shared configuration of the first heat dissipation fin 15 and the second heat dissipation fin 15), which is not adopted in the standard PTC heat generating device 100 due to its poor heat dissipation efficiency. By storing heat in the heat dissipation fins with this configuration, it is possible to maintain warm air even in a minus environment. In addition, by setting the wind speed to 3.5 m / s or less, it is possible to reduce power consumption. In particular, when heating the feet inside a vehicle cabin of an EV (Electric Vehicle) in a cold region, heating in a minus environment is essential. Even in such a situation, this embodiment provides a heating configuration that provides sufficient heating performance and reduces battery consumption (electricity cost).

[0063] (PTC heating device control) FIG. 14 is a schematic diagram for explaining the control of the PTC heating device according to this embodiment. As shown in FIG. 14, the PTC heating device 1 may further include a blower 50 having a rotor 51 that sends air to the PTC heater block HB, a temperature sensor 60 that detects the temperature in the vicinity of the PTC heater block HB, and a control unit 70 that controls the rotation of the rotor 51 of the blower 50 based on the temperature detected by the temperature sensor 60.

[0064] For example, the PTC heating device 1 and the blower 50 are disposed inside the duct 200. The outer dimensions of the PTC heater block HB are preferably set to be the same size as the circumscribing rectangle of the rotor 51. This allows the PTC heating device 1 and the blower 50 to be disposed without any gaps inside the duct 200, so that the air sent from the rotor 51 can be effectively sent to the PTC heater block HB.

[0065] In such a configuration, when the temperature detected by the temperature sensor 60 exceeds a preset temperature while the rotation speed of the rotor 51 is controlled to a first rotation speed, the control unit 70 controls the rotation speed of the rotor 51 to a second rotation speed higher than the first rotation speed. The control unit 70 is supplied with power from the power supply unit 80, and controls the power sent to the PTC heating device 1 and the blower 50.

[0066] In the PTC heating device 1, the ultimate temperature can be lowered by increasing the wind speed of the air sent from the blower 50 to the PTC heater block HB. This is because, in the balance between the heat generation in the PTC heating element and the heat release from the heat dissipation fins, the higher the wind speed, the more heat is released from the heat dissipation fins (the less heat stored in the heat dissipation fins), and as a result, the ultimate temperature after a certain period of time becomes lower. In this embodiment, this characteristic is utilized, and when the temperature detected by the temperature sensor 60 reaches the set temperature, the wind speed of the rotor 51 is increased to promote heat dissipation from the heat dissipation fins, thereby controlling to lower the ultimate temperature.

[0067] On the other hand, when the temperature detected by the temperature sensor 60 falls below a preset temperature, the rotation speed of the rotor 51 is controlled to be lower than the second rotation speed. This increases the ultimate temperature, in the opposite manner to the previous example, and the temperature in the space can be increased.

[0068] In this manner, in this embodiment, the temperature of the space created by the PTC heating device 1 can be controlled by the rotation speed of the rotor 51.

[0069] (Other embodiments) FIG. 15 is a perspective view showing an example in which a PTC heater block and a blower are integrated together. As shown in FIG. 15, for example, if the outer dimensions of the PTC heater block HB of the PTC heating device 1 are the same size as the circumscribing rectangle of the rotor 51, it is easy to integrate the blower 50 into a compact unit by stacking it on top of the PTC heater block HB and connecting it (facing connection).

[0070] In this PTC heating device 1, a control unit 70 may be attached to the housing 52 of the blower 50. A power supply line L1 and a signal line L2 from the temperature sensor 60 (see FIG. 8) are connected to the control unit 70 as input lines, and a rotation control signal line L3 for controlling the rotation of the rotor 51 and a current control line L4 for controlling the current supply to the PTC heating device 1 are connected to the control unit 70 as output lines.

[0071] Here, when the PTC heater block HB and the blower 50 are connected facing each other and integrated, if the distance between the PTC heater block HB and the blower 50 is too narrow, heat from the PTC heater block HB is transferred to the housing 52 of the blower 50, and the housing 52 is likely to be heated. On the other hand, if the distance between the PTC heater block HB and the blower 50 is too wide, the advantage of compactness achieved by integration is lost. Therefore, it is important to set an appropriate distance between the PTC heater block HB and the blower 50.

[0072] 16 to 18 are diagrams showing the relationship between the distance between the PTC heater block and the blower and the temperature of the blower. Here, the PTC heater block HB is supported by a frame made of resin (e.g., PPS: polyphenylene sulfide) not shown, and the distance between the PTC heater block HB and the blower 50 is set by a spacer 53 arranged between them. Fig. 16 shows the temperature reached when the distance between the PTC heater block HB and the blower 50 is 5 mm, Fig. 17 shows the temperature reached when the distance between the PTC heater block HB and the blower 50 is 10 mm, and Fig. 18 shows the temperature reached when the distance between the PTC heater block HB and the blower 50 is 15 mm. Each figure shows the results of measuring the surface temperature of the frame supporting the TC heater block HB and the surface temperature of the housing 52 of the blower 50 when the blowing of air from the blower 50 is stopped (windless state).

[0073] As shown in Fig. 16, when the distance between the PTC heater block HB and the blower 50 is 5 mm, heat from the PTC heater block HB is easily transferred to the blower 50, and the surface temperature of the housing 52 of the blower 50 is higher than the surface temperature of the frame of the PTC heater block HB. As shown in Fig. 17 and Fig. 18, when the distance between the PTC heater block HB and the blower 50 is 10 mm or more, the phenomenon in which the surface temperature of the housing 52 of the blower 50 is higher than the surface temperature of the frame of the PTC heater block HB does not occur. From this result, it can be seen that setting the distance between the PTC heater block HB and the blower 50 to about 10 mm is preferable in that it is possible to miniaturize the PTC heating device 1 integrated with the blower 50 while suppressing heating of the housing 52.

[0074] Furthermore, by integrating the PTC heater block HB and the blower 50 in this way, the distance between the PTC heater block HB and the blower 50 can be made constant (fixed). This makes it difficult for the wind speed and volume of the air sent from the blower 50 to the heater block HB to be affected by disturbances. Therefore, it becomes easier to perform stable and accurate temperature control by the wind speed and volume of the air sent from the blower 50 to the PTC heater block HB.

[0075] 19 and 20 show PTC heating devices 1B and 1C having a different number of heat dissipating fins and PTC heating members from the PTC heating device 1 shown in FIG. The PTC heat generating device 1B shown in Fig. 19 has a PTC heater block HB in which three heat dissipating fins 45 and two PTC heat generating members 40 are alternately stacked one by one. The PTC heat generating device 1C shown in Fig. 20 has a PTC heater block HB in which five or more heat dissipating fins 45 and PTC heat generating members 40, the number of which is one less than the heat dissipating fin 45, are alternately stacked one by one.

[0076] Both the PTC heating devices 1B and 1C include a PTC heater block HB having N (N is an integer of 3 or more) heat dissipation fins 45 and N-1 PTC heating members 40 with electrode layers on the front and back, and the N heat dissipation fins 45 and the N-1 PTC heating members 40 are stacked alternately one by one. As a result, both the PTC heating devices 1B and 1C are configured such that two adjacent PTC heating members 40 share one heat dissipation fin 45 provided between them.

[0077] In this configuration, over the entire temperature range of the air sent to the PTC heater block HB from negative to room temperature in Celsius, the N-1 PTC heat generating components 40 as a whole operate within a temperature range above the temperature Tm indicating the minimum resistance value Rmin and below the Curie point Tc, i.e., within the range of positive temperature characteristics, so that even when the ambient temperature is low, heat can be actively stored in the heat dissipation fins to obtain a sufficient amount of heat.

[0078] As described above, according to the present embodiment, it is possible to provide the PTC heating devices 1, 1B, and 1C that can efficiently heat even when the wind speed and the ambient temperature are low.

[0079] Although the present embodiment and its application examples have been described above, the present invention is not limited to these examples. For example, those in which a person skilled in the art appropriately adds, deletes, or modifies the design of the above-mentioned embodiments or their application examples, or those in which the features of the embodiments are appropriately combined, are also included in the scope of the present invention as long as they include the gist of the present invention. [Industrial Applicability]

[0080] The present invention can be used as a heating mechanism part of moving objects such as automobiles, trains, ships, and airplanes, bathroom dryers, drum-type washing and drying machines, dishwashers, and futon dryers. [Explanation of symbols]

[0081] 1,1B,1C…PTC heating device 10...First PTC heating element 11, 21, 31...PTC element 12,22,32...electrode layer 13,23,33...electrode part 15…First heat dissipation fin 17...Insulating resin 20...Second PTC heating element 25…Second heat dissipation fin 30…Central PTC heating element 40...PTC heating element 45…Heat dissipation fin 50…Blower 51...Rotor 52…Housing 53…Spacer 60...Temperature sensor 70...Control unit 80...Power supply section 100...Standard PTC heating device 151, 251...Plate-shaped member 152,252...Extension part 200…Duct 210...Box body HB...PTC heater block HM1…First heater module HM2: Second heater module L1…Supply line L2: Signal line L3: Rotation control signal line L4: Power supply control line

Claims

1. A PTC heating device including a PTC heater block having N heat dissipation fins (N is an integer of 3 or more) and N-1 PTC (Positive Temperature Coefficient) heat generating members stacked alternately one by one, with one heat dissipation fin shared between two adjacent PTC heat generating members, The PTC heat generating member has a PTC element and electrode layers provided on both the front and back surfaces of the PTC element, each of the N heat dissipation fins is made of a conductive material and is electrically connected to the electrode layer of the PTC element by a heat-resistant adhesive; one side of the pair of heat dissipation fins sandwiching the PTC heat generating component therebetween is a positive electrode and the other side is a negative electrode, and the polarities of the N heat dissipation fins are alternately positive and negative in the stacking direction to apply a predetermined voltage to the PTC element, a first direction is a stacking direction of the heat dissipation fins and the PTC heat generating component, a second direction is a length direction perpendicular to the first direction, and a third direction is a width direction perpendicular to the first direction and the second direction, the length of the PTC heater block in the first direction is 3 cm or more and 5 cm or less, the length of the PTC heater block in the second direction is 3 cm or more and 5 cm or less, and the length of the PTC heater block in the third direction is 20 mm or more and 24 mm or less, A PTC heating device configured so that the N-1 PTC heating components as a whole operate in a temperature range above the temperature showing the minimum resistance value in the PTC temperature-resistance characteristics and below the Curie point, over the entire temperature range of the air sent to the PTC heater block from negative to room temperature in Celsius.

2. 2. The PTC heating device according to claim 1, wherein the N-1 PTC heating members as a whole are configured to operate in a temperature range from the temperature showing the minimum resistance value in the PTC temperature-resistance characteristics to the Curie point when the wind speed of the air sent to the PTC heater block is in a range of 3.5 m / s or less.

3. a blower having a rotor for blowing air to the PTC heater block; a temperature sensor for detecting a temperature in the vicinity of the PTC heater block; A control unit that controls rotation of the rotor based on the temperature detected by the temperature sensor, 2. The PTC heating device according to claim 1, wherein when the temperature detected by the temperature sensor exceeds a preset temperature while the rotation speed of the rotor is controlled to a first rotation speed, the control unit controls the rotation speed of the rotor to a second rotation speed higher than the first rotation speed.

4. A blower having a rotor for blowing air to the PTC heater block is further provided, 2. The PTC heating device according to claim 1, wherein the outer dimensions of said PTC heater block are set to be equal to a circumscribing rectangle of said rotor blade.

5. 5. The PTC heating device according to claim 4, wherein the air blower is connected opposite to the PTC heater block.

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