PTC heating device

Abstract

To provide a PTC heating device capable of efficiently heating even when the wind speed and the ambient temperature are low.SOLUTION: A PTC heating device according to an embodiment includes 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 heat generating components alternately one by one, and configured such that the N-1 PTC heat generating 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 degrees Celsius.SELECTED DRAWING: Figure 2

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] Heat generating devices using PTC (Positive Temperature Coefficient) heating elements utilize the positive temperature characteristics of the PTC heating element to facilitate temperature control and reduce power consumption. PTC heating devices are configured with a pair of heat dissipation fins sandwiching the PTC heating element, allowing the heat generated by the PTC heating element to be effectively dissipated to the outside through the heat dissipation fins.

[0003] Patent Document 1 discloses a PTC unit for a vehicle heater, which includes a heat generating part including a PTC element, and a heat dissipation part provided on at least one surface of the heat generating part, which includes a heat dissipation substrate and a heat dissipation coating provided on at least a part of the outer surface of the heat dissipation substrate to improve heat dissipation performance. Also, Patent Documents 2 and 3 disclose a PTC heater structure in which multiple PTC elements and multiple heat dissipation 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] Japanese Patent Application Laid-Open No. 2007-157528 Summary of the Invention [Problem to be solved by the invention]

[0005] When air is blown into a PTC heater block that combines a PTC heating element and heat dissipation fins using a blower (fan), if the temperature of the air (ambient temperature) is low, it will operate at a temperature much lower than the Curie temperature of the PTC heating element. For this reason, for example, when warming a narrow space (such as the foot space in a vehicle interior), if a very high wind speed is not required, it cannot be warmed sufficiently, and moreover, since it will be driven in a low-resistance state, power will be wasted.

[0006] An object of the present invention is to provide a PTC heating device that can efficiently warm even when the wind speed is low and the ambient temperature is 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 alternately stacking N (N is an integer of 3 or more) heat dissipation fins and N - 1 PTC heating members one by one, wherein the temperature of the air sent to the PTC heater block is in the temperature range from minus to room temperature in degrees Celsius, and as a whole, the N - 1 PTC heating members are provided to operate in a temperature range from the temperature at which the lowest resistance value in the temperature-resistance characteristics of PTC is exhibited to below the Curie point.

[0008] According to such a configuration, in the entire temperature range from minus to room temperature in degrees Celsius of the air sent to the PTC heater block, all of the N - 1 PTC heating members operate in a temperature range from the temperature at which the lowest resistance value in the temperature-resistance characteristics of PTC is exhibited to below the Curie point, that is, 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 a sufficient amount of 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 above the temperature showing the minimum resistance value in the PTC temperature-resistance characteristic and below 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, 3.5 m / s or less, and sufficient heat generation 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 HB, 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. This allows the amount of heat generated by the PTC heater block HB to be controlled by the rotation speed of the rotor.

[0011] The PTC heating device may further include a blower with a rotor that sends air to the PTC heater block, and the outer dimensions of the PTC heater block may be set to the same size as the circumscribed rectangle of the rotor. This allows the air sent from the rotor of the blower to be sent effectively to the PTC heater block. In this case, the blower may be connected opposite the PTC heater block. This realizes a device configuration in which the PTC heater block and the blower are integrated. [Effects 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 explanation of the drawings]

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

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same components will be designated by the same reference numerals, and the description of components 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 this embodiment. FIG. 2 is an exploded perspective view illustrating the configuration of the PTC heating device according to this embodiment. FIG. 3 is a cross-sectional view illustrating the configuration of the PTC heating device according to this embodiment. The PTC heating device 1 according to this embodiment is a device that generates heat when a voltage is applied. 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 elements alternately one by one. In this embodiment, the case where N=4 will be described as an example, but the experimental results described below also include examples where 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 stacked in this order.

[0017] In addition, in this embodiment, for convenience of explanation, the direction in which the first heater module HM1, the central PTC heating member 30, and the second heater module HM2 are stacked is referred to as the first direction D1, the direction orthogonal to the first direction D1 and in which the first heater module HM1 and the second heater module HM2 extend is referred to as the second direction D2, and the direction orthogonal to the first direction D1 and the second direction D2 is referred to as the third direction D3. Also, the first direction D1 is also referred to as the thickness (or stacking) direction, the second direction D2 is also referred to as the length direction, and the third direction D3 is also referred to as the width direction. Here, in FIG. 2, the insulating resin 17 described later is shown by a two-dot chain line. Also, FIG. 3 is a cross-sectional view of the PTC heating 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 includes a first PTC heating member 10, a pair of electrode portions 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 heating member 10 is sandwiched between a pair of electrode portions 13 and a pair of first heat dissipation fins 15.

[0019] The first PTC heating member 10 includes 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 coefficient. That is, when the temperature reaches or exceeds the Curie point, the resistance increases, and further temperature rise is restricted. By using the PTC element 11, it is possible to facilitate temperature control and suppress power consumption. In this embodiment, a plurality (for example, two) of PTC elements 11 are juxtaposed in the second direction D2 (length direction), but one may be used, or three or more may be juxtaposed. Also, a plurality of PTC elements 11 may be juxtaposed in the third direction D3 (width direction).

[0020] Metals such as silver (Ag) and aluminum (Al) are used as the material of the electrode layers 12 provided on the front and back of the PTC element 11. The electrode layers 12 are formed by, for example, spraying these metals on the front and back surfaces of the PTC element 11. Minute irregularities are provided on the surface of the electrode layer 12 formed by spraying the metal. Also, 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 component 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 these plate-like members 151 (the one on the first PTC heat generating component 10 side) is used as the electrode unit 13.

[0022] The electrode portion 13 and the first heat dissipation fins 15 are made of, for example, stainless steel or aluminum. The first heat dissipation fins 15 are formed, for example, by bending an aluminum plate so that peaks and valleys are repeated. The pair of first heat dissipation fins 15 are, for example, of the same size and have the same thermal resistance. By electrically connecting the first heat dissipation fins 15 to the electrode portion 13, the first heat dissipation fins 15 can be used as a conduction 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-dissipating fin 15, and a voltage-applying cable (not shown) is connected to this extension portion 152. This allows a predetermined voltage to be applied to the first PTC heat-generating member 10 from the cable via the plate-like member 151 and the first heat-dissipating fin 15.

[0024] The periphery of the first PTC heat generating component 10 sandwiched between the pair of first heat dissipation fins 15 (excluding the surfaces of the electrode layers 12 on the front and back) 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 (such as a conductive silicone adhesive). As a result, the first heat dissipation fin 15 on the side of the central PTC heat generating component 30 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 a configuration similar to that of the first heater module HM1. Specifically, the second heater module HM2 includes a second PTC heat generating member 20, a pair of electrode portions 23, and a pair of second heat dissipation fins 25. The second PTC heat generating member 20 is similar to the first PTC heat generating member 10, the PTC element 21 is similar to the PTC element 11, and the electrode layer 22 is similar to the electrode layer 12. The pair of electrode portions 23 are similar to the pair of electrode portions 13, and the pair of second heat dissipation fins 25 are similar to the pair of first heat dissipation fins 15. Furthermore, the plate-shaped member 251 is similar to the plate-shaped member 151, and the extension portion 252 is similar to the extension portion 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 sides of the central PTC heat generating member 30.

[0027] (Structure of the 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 sides 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. Furthermore, 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 sides) 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 sides, respectively.

[0029] In this embodiment, of the pair of first heat dissipation fins 15, the plate-like member 151 on the central PTC heat generating component 30 side of the first heat dissipation fin 15 is used as the electrode portion 33. Also, of the pair of second heat dissipation fins 25, the plate-like member 251 on the central PTC heat generating component 30 side of the second heat dissipation fin 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 electrically connected to the electrode portion 33 on one side of the front or back, and the second heat dissipation fin 25 is electrically connected to 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 such an embodiment, four heat dissipation fins (a pair of first heat dissipation fins 15 and a pair of second heat dissipation fins 25) and three PTC heating members (a first PTC heating member 10, a central PTC heating member 30, and a 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 dissipation fin provided therebetween. For example, the first heat dissipation fin 15 disposed 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. Also, the second heat dissipation fin 25 disposed between the second PTC heating member 20 and the central PTC heating member 30 is configured to be shared by the second PTC heating member 20 and the central PTC heating member 30.

[0033] Further, 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 conduction paths for voltage application to each PTC element, the polarities of the voltages applied to each of the four heat dissipation fins are in the order of positive electrode, negative electrode, positive electrode, negative electrode (or the reverse order). An example of the size of the heater block HB of the PTC heating device 1 is a thickness of about 3 cm to about 5 cm, a length of about 3 cm to about 5 cm, and a width of about 2 cm.

[0034] In such a PTC heating device 1 according to this embodiment, in the entire temperature range from minus to room temperature in degrees Celsius of the air sent to the PTC heater block HB, 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 below the Curie point and above the lowest resistance value in the temperature-resistance characteristics of PTC. That is, the heater block HB operates in the region of positive temperature characteristics in the temperature range including minus in degrees Celsius. Thereby, even when the ambient temperature is low, it operates in the range of positive temperature characteristics, actively stores heat in the heat dissipation fins, and can obtain a sufficient amount of heat generation.

[0035] FIG. 4 is a diagram illustrating the temperature-resistance characteristics of the PTC heating member. 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 these temperature-resistance characteristics, the temperature inside the thermostatic chamber in a windless state is considered to be the temperature of the PTC heat generating component. As shown in Figures 4 and 5, the PTC heating element has the characteristic that its resistance rises sharply near its Curie point Tc. Here, the Curie point Tc is the temperature at which the resistance 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), and barium (Ba) when mixing the materials for 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 decrease from the resistance value R25 at room temperature to the minimum resistance value Rmin, and then 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 element 10, the second PTC heating element 20 and the central PTC heating element 30 as a whole are configured to operate in a temperature range (characteristic temperature range) above the temperature Tm showing the minimum resistance value Rmin and below the Curie point Tc, over the entire temperature range of negative to room temperature in degrees Celsius 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 reference PTC heating device. The reference PTC heating device 100 has a configuration in which the first heater module HM1 and the second heater module HM2 are directly connected without providing the central PTC heating member 30 of the PTC heater block HB of the PTC heating device 1 according to the present 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 members 10, and a pair of second heat dissipation fins 25 are provided between the second PTC heating members 20. Therefore, the heat dissipation fins are not shared between the first PTC heating member 10 and the second PTC heating member 20.

[0039] In the PTC heating device 1 having three PTC heating members, the absolute output is higher than that of the reference PTC heating device 100 having two PTC heating members. However, in the PTC heating device 1 according to the present embodiment, since two adjacent PTC heating members share one heat dissipation fin provided therebetween, 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 by the heat dissipation fins in the PTC heating device 1 is sufficiently increased (if heat dissipation fins with sufficiently low thermal resistance are used), even if there is a difference in the number of PTC heating members, the temperature characteristics with respect to the wind speed in the PTC heating device 1 and the reference PTC heating device 100 will be the same. However, in the present embodiment, a configuration is adopted in which the heat dissipation fins are shared to intentionally 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 the same, but in the PTC heating device 1, the heat dissipation fins between two adjacent PTC heating members are shared. As a result, in the PTC heating device 1, compared with the configuration where the heat dissipation fins are not shared, the accumulation of heat in the heat dissipation fins is promoted, and even when the ambient temperature is low, as a whole of the PTC heating members, it is configured to operate in a temperature range below the Curie point Tc and above the temperature Tm at which the minimum resistance value Rmin is exhibited. 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 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, assuming that it operates in the range from the resistance value R25 to the minimum resistance value Rmin (the range of negative temperature characteristics) at a temperature lower than the Curie point Tc, a phenomenon occurs in which the resistance value increases as the ambient temperature decreases (a phenomenon due to negative temperature characteristics). This leads to a further decrease in the heating temperature, resulting in a vicious cycle in which this causes a further increase in the resistance value.

[0042] In the PTC heating device 1 according to the present embodiment, in the entire temperature range from minus to room temperature in degrees Celsius of the air sent to the PTC heater block HB, as a whole, 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 below the Curie point Tc and above the temperature Tm indicating the minimum resistance value Rmin.

[0043] Furthermore, in the PTC heating device 1 according to the present embodiment, one more PTC heating member is provided than in the reference PTC heating device 100, and by sharing one heat radiation fin between two adjacent PTC heating members, heat accumulation in the heat radiation fin (heat is accumulated by reducing the heat radiation efficiency of the heat radiation fin by sharing) is actively utilized. With these configurations, the PTC heating device 1 can be sufficiently heated even at a low ambient temperature, 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] Whether the first PTC heat generating element 10, the second PTC heat generating element 20, and the central PTC heat generating element 30 as a whole are operating in the temperature range above the temperature Tm showing the minimum resistance value Rmin and below the Curie point Tc can be determined by changing the temperature of the air sent to the PTC heater block HB and observing the change in the amount of current (resistance value) when electricity is passed through the PTC heater block HB. For example, if the temperature of the air sent to the PTC heater block HB is raised from negative Celsius to room temperature, and 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 coefficient.

[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, and the PTC heating device 1 and a blower 50 are placed inside the duct 200, with air being sent from the blower 50 to the PTC heating device 1. Then, with the PTC heating device 1 energized to generate heat, the temperature reached at a predetermined position in 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 measurement points are four points at positions A, B, C, and D inside the box body 210. Position A is the air outlet of the PTC heating device 1. Position B is the central part of the bottom of the box body 210. Position C is the central part of the box body 210. Position D is the central part of the ceiling of the box body 210. The horizontal distance from the air outlet to positions B, C, and D is about 20 cm. The height-direction intervals between position B and position C, and between position C and position D are each about 20 cm.

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

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

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

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

[0052] Comparing the outputs in Figure 8(b) and Figure 9(b), the output at a wind speed of 0.5 m / s shown in Figure 8(b) decreases over time, but the output at 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 small space such as the foot area in a car, it is sufficient to heat the area within a distance of several tens of centimeters from the hot air outlet. As shown in Figure 7, it is sufficient to have a sufficient temperature around positions C and D (around the foot pedal position). As shown in Figures 8(a) and 9(a), positions C and D both reach 30°C in a few minutes. On the other hand, the output is lower at an air velocity of 0.5 m / s. In other words, the PTC heating device 1 according to this embodiment can obtain a sufficient heating temperature even at a low air velocity, and the output required for this can be low. This is because the heat storage effect of the heat dissipation fins is effectively utilized.

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

[0055] The PTC heating device 1 according to this embodiment is designed to operate in the temperature range from the minimum resistance value Rmin (Tm) to the Curie point Tc across the entire PTC heating element, over the entire ambient temperature range from minus Celsius to room temperature. Therefore, even if the ambient temperature is, for example, -20°C, it can reach temperatures exceeding 60°C.

[0056] Here, if the ambient temperature is low and the plurality of PTC heating elements operate as a whole in the range of negative temperature characteristics, sufficient heating characteristics cannot be obtained. For example, when the ambient temperature is low enough to be negative in degrees Celsius, if the PTC heating element operates in the region where it has negative temperature characteristics (the region that descends from the resistance value at room temperature shown in FIG. 5 to the minimum resistance value Rmin), the resistance value will increase as the temperature decreases, and sufficient heating characteristics cannot be obtained.

[0057] In this embodiment, even when the ambient temperature is negative in degrees Celsius, the plurality of PTC heating elements are configured to operate as a whole in the temperature range from the temperature Tm indicating the minimum resistance value Rmin to below the Curie point Tc, so that the resistance value decreases as the temperature decreases, and sufficient heating characteristics can be obtained. For example, in the PTC heating device 1 according to this embodiment, even when the ambient temperature is about -50°C, it is configured to operate in the temperature range from the temperature Tm indicating the minimum resistance value Rmin to below the Curie point Tc. Thereby, sufficient heating characteristics can be obtained even at low temperatures. Moreover, since the temperature range in which it is driven at a resistance value higher than the resistance value R25 at room temperature is also included, power consumption can be reduced.

[0058] (Heating characteristics due to configuration differences) FIGS. 11 to 13 are diagrams illustrating heating characteristics due to configuration differences. FIGS. 11 to 13 show the relationship between the wind speed by the blower 50 and the reaching temperature. In each figure, the respective relationships are shown when the temperatures of the air sent by the blower 50 are -25°C, 0°C, and 25°C as parameters. Here, the reaching temperature at position A is measured when air at wind speeds of 1.0 m / s, 2.0 m / s, 3.0 m / s, and 4.0 m / s is sent from the duct 200 shown in FIG. 7 toward the heater block HB and heated for 3 minutes.

[0059] Figure 11 shows the characteristics of a PTC heating device equipped with two PTC heating elements (N=3) and a heater block HB measuring 40 mm in length, 40 mm in height, and 15 mm in width. Figure 12 shows the characteristics of a PTC heating device equipped with three PTC heating elements (N=4) and a heater block HB measuring 40 mm in length, 40 mm in height, and 15 mm in width. Figure 13 shows the characteristics of a PTC heating device equipped with three PTC heating elements (N=4) and a heater block HB measuring 40 mm in length, 40 mm in height, and 24 mm in width.

[0060] As shown in Figures 11 to 13, the greater the number of PTC heat generating elements, the higher the temperature achieved at any temperature and wind speed. Furthermore, as shown in Figures 12 and 13, even with the same number of PTC heat generating elements, a heater block HB with a narrower width achieves a higher temperature at relatively low temperatures such as 0°C and -25°C, 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, resulting in heat accumulation in the heat dissipation fins.

[0061] In ceramic fan heaters and the like that use 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 equipment that is used in such high-speed conditions, the PTC heating element will operate in the negative temperature characteristic range when the temperature falls into the negative temperature range, and sufficient temperature characteristics cannot be obtained.

[0062] To solve this problem of negative temperature characteristics, this embodiment intentionally adds a central PTC heat-generating element 30 (a shared configuration of the first and second heat-radiating fins 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-radiating fins with this configuration, warm air can be maintained even in subzero temperatures. Furthermore, by limiting the air velocity to 3.5 m / s or less, power consumption can be reduced. Heating in subzero temperatures is particularly essential when heating the footwell area of an electric vehicle (EV) in cold regions. Even in such conditions, this embodiment provides a heating configuration that provides sufficient heating performance while suppressing battery consumption (electricity cost).

[0063] (PTC heating device control) FIG. 14 is a schematic diagram illustrating 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 near 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 placed inside the duct 200. The external dimensions of the PTC heater block HB are preferably set to be the same size as the circumscribed rectangle of the rotor blades 51. This allows the PTC heating device 1 and the blower 50 to be placed tightly inside the duct 200, so that the air sent from the rotor blades 51 can be sent effectively to the PTC heater block HB.

[0065] In this 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 that is 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 temperature that can be reached 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 generation of heat in the PTC heating element and the release of heat from the heat radiation fins, the higher the wind speed, the greater the amount of heat released from the heat radiation fins (the less the heat storage amount of the heat radiation fins), and as a result, the temperature that can be reached 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, control is performed to increase the wind speed of the rotary blade 51 to promote heat radiation from the heat radiation fins and lower the temperature that can be reached.

[0067] On the other hand, when the temperature detected by the temperature sensor 60 is lower than the preset temperature, control is performed to set the rotational speed of the rotary blade 51 to a rotational speed lower than the second rotational speed. As a result, contrary to the above, the temperature that can be reached increases, and the temperature of the space can be increased.

[0068] In this way, in this embodiment, it becomes possible to control the temperature of the space by the PTC heating device 1 by the rotational speed of the rotary blade 51.

[0069] (Other embodiments) FIG. 15 is a perspective view showing an example in which the PTC heater block and the blower are integrated. 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 circumscribed rectangle of the rotary blade 51, by overlapping and connecting the blower 50 to the PTC heater block HB (opposite connection), it becomes easy to integrate them compactly.

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

[0071] Here, when the PTC heater block HB and the blower 50 are connected and integrated in a facing manner, if the distance between the PTC heater block HB and the blower 50 is too narrow, the heat from the PTC heater block HB will be transmitted to the housing 52 of the blower 50, and the housing 52 will be easily heated. On the other hand, if the distance between the PTC heater block HB and the blower 50 is made too wide, the merit of miniaturization by integration will be impaired. Therefore, it is important to set an appropriate distance between the PTC heater block HB and the blower 50.

[0072] Figures 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 resin (for example, PPS: polyphenylene sulfide) frame (not shown), and the distance between the PTC heater block HB and the blower 50 is set by a spacer 53 disposed therebetween. Figure 16 shows the reaching temperature when the distance between the PTC heater block HB and the blower 50 is 5 mm, Figure 17 shows the reaching temperature when the distance between the PTC heater block HB and the blower 50 is 10 mm, and Figure 18 shows the reaching temperature when the distance between the PTC heater block HB and the blower 50 is 15 mm. In each figure, the blowing from the blower 50 is stopped (windless state), and 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 are shown.

[0073] As shown in Fig. 16, when the distance between the PTC heater block HB and the blower 50 is 5 mm, the heat from the PTC heater block HB is easily transmitted 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 Figs. 17 and 18, when the distance between the PTC heater block HB and the blower 50 becomes 10 mm or more, the phenomenon that 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 if the distance between the PTC heater block HB and the blower 50 is set to about 10 mm, it is preferable in that the PTC heating device 1 integrated with the blower 50 can be downsized while suppressing the heating of the housing 52.

[0074] Also, in this way, by integrating the PTC heater block HB and the blower 50, the distance between the PTC heater block HB and the blower 50 can be made constant (fixed). As a result, the wind speed and air volume of the air sent from the blower 50 to the heater block HB are less likely to be affected by disturbances. Therefore, it becomes easier to perform stable and accurate temperature control according to the wind speed and air volume of the air sent from the blower 50 to the PTC heater block HB.

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

[0076] Both the PTC heating devices 1B and 1C include a PTC heater block HB that includes 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 that is configured such that 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, the N-1 PTC heat generating members 40 as a whole operate within a temperature range above the temperature Tm showing the minimum resistance value Rmin and below the Curie point Tc, i.e., within the range of positive temperature characteristics, over the entire temperature range in which the temperature of the air sent to the PTC heater block HB ranges from negative to room temperature in degrees Celsius. Therefore, even when the ambient temperature is low, heat can be actively stored in the heat dissipation fins to generate sufficient heat.

[0078] As described above, according to this 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, any embodiment or application example in which a person skilled in the art appropriately adds, deletes, or modifies components, or appropriately combines features of the above embodiments, is also included within the scope of the present invention as long as it includes the gist of the present invention. [Industrial Applicability]

[0080] The present invention can be used as a heating mechanism part for 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...Case 53...Spacer 60...Temperature sensor 70...Control unit 80...Power supply section 100...Standard PTC heating device 151, 251...Plate-shaped members 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...Electrification control line

Claims

1. A PTC heating device including a PTC heater block configured by alternately laminating N (where N is an integer of 3 or more) heat dissipation fins and N-1 PTC (Positive Temperature Coefficient) heating members one by one, The temperature of the air sent to the PTC heater block is in the entire temperature range from minus to room temperature in degrees Celsius, and as a whole, the N-1 PTC heating members operate in a temperature range equal to or higher than the temperature showing the minimum resistance value in the temperature-resistance characteristics of PTC and equal to or lower than the Curie point. A PTC heating device provided in a configuration.

2. In a wind speed range where the wind speed of the air sent to the PTC heater block is 3.5 m / s or less, as a whole, the N-1 PTC heating members operate in a temperature range equal to or higher than the temperature showing the minimum resistance value in the temperature-resistance characteristics of PTC and equal to or lower than the Curie point. A PTC heating device provided in a configuration.

3. A temperature sensor for detecting the temperature near the PTC heater block, A control unit for controlling the rotation of the rotary wing based on the temperature detected by the temperature sensor, and further comprising: The control unit performs control to set the rotation speed of the rotary wing 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 rotary wing is controlled to the first rotation speed. The PTC heating device according to claim 1.

4. Further comprising a blower equipped with a rotary wing for sending air to the PTC heater block, The PTC heating device according to claim 1, wherein the outer dimensions of the PTC heater block are provided in the same size as the circumscribed rectangle of the rotary wing.

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

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