Vehicle heater control device

Abstract

To provide a vehicle heater control device capable of improving passenger comfort even when a vehicle interior temperature fluctuates.SOLUTION: A vehicle heater control device 1 includes a thermostat 12B which switches between a conduction state and a non-conduction state of a heat generation section 11 on a seat heater 10 heating a seat face 2A of a seat cushion 2. The thermostat 12B is: arranged at a position at a distance from the heat generation section 11 and exposed to a vehicle interior; and electrically connected to the heat generation section 11 through a lead line 14 extended from the heat generation section 11. The vehicle heater control device 1 also includes an overheat prevention thermostat 17 which is installed on the heat generation section 11. The overheat prevention thermostat 17 switches the heat generation section 11 in the conduction state to the non-conduction state when an element temperature of the heat generation section exceeds an overheat prevention temperature.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a vehicle heater control device. [Background technology]

[0002] Conventionally, a heater is provided near the seat of a vehicle such as an automobile. The heater is provided with a heat-generating member such as a copper wire that generates heat when electricity is passed through it, and the heat generated by the heat-generating member is transferred to the occupant through the cushion material and surface layer that constitute the seat. This type of heater is called an electric heater, and there are other types such as a radiant heater that transfers heat to the occupant by electromagnetic waves and a convection heater that transfers convection heat to the occupant by blowing warm air (air-conditioned air) to the occupant.

[0003] Known prior art techniques for controlling electric heaters include a method of switching only the heater's conductive (ON) and non-conductive (OFF) states, a method that allows the selection of high temperature (Hi) or low temperature (Low) as the operating setting when the heater is conductive, or a method that allows the selection of high temperature (Hi), medium temperature (Mid) or low temperature (Low) (see, for example, Patent Document 1). In all of these control methods, the conductive and non-conductive states of the heater are controlled so that the seat temperature becomes the target value determined at the time of design. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-301427 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, it is desirable to control the electric heater by controlling the conductive and non-conductive states of the heater so that the seat temperature is high when the interior of the vehicle is cold and low when the interior of the vehicle is warm. Normally, when the interior of the vehicle is cold, the air conditioning (heating) is operated, and the temperature inside the vehicle increases over time. It is desirable to control the heater so that the seat temperature gradually decreases in accordance with the increase in the temperature inside the vehicle. Conversely, when the temperature inside the vehicle temporarily decreases due to the opening and closing of the door when getting in and out of the vehicle, it is desirable to control the heater so that the seat temperature increases in accordance with the decrease in temperature.

[0006] However, in the control method for the conventional electric heater described above, the heater is controlled so that the seat temperature is maintained at a predetermined value regardless of the temperature inside the vehicle cabin, which causes the following problems: In other words, in a method that switches only between heater ON and OFF, if the target value of the seat temperature is set so that the occupant feels comfortable when the vehicle cabin is cold, the seat may feel hot when the vehicle cabin is warm, which may cause the occupant to feel uncomfortable. On the other hand, if the target value of the seat temperature is set so that the occupant feels comfortable when the vehicle cabin is warm, the seat may feel cold when the vehicle cabin is cold, which may cause the occupant to feel uncomfortable.

[0007] In addition, in the method of selecting the operation setting when the heater is in a conductive state, the occupant can manually change the temperature setting of the seat, but the changeover operation means, for example, selecting "low temperature (Low)" if the seat feels hot, and selecting "high temperature (Hi)" if the seat feels cold. In other words, the occupant has no choice but to change the operation setting of the heater when he or she feels uncomfortable. This makes it difficult to control the heater in a way that keeps the occupant comfortable at all times.

[0008] As described above, the conventional technology for controlling electric heaters requires the occupant to turn off the heater or change the heater operation settings if the occupant feels that the seat surface is too hot, leaving room for improvement in terms of improving occupant comfort. This is an issue not only for electric heaters that warm the seat surface of vehicle seats, but is common to electric heaters that warm various vehicle components that occupants touch.

[0009] The present invention has been made in light of the above points, and aims to provide a vehicle heater control device that can improve the comfort of occupants even when the temperature inside the vehicle cabin changes. [Means for solving the problem]

[0010] In order to achieve the above object, one aspect of the present invention provides a vehicle heater control device including a main switching element for switching between a conductive state and a non-conductive state of a heater that generates heat by conduction to warm vehicle components, the main switching element being configured to switch the heater to a non-conductive state when the element temperature of the heater exceeds an operating temperature in the conductive state of the heater, and to switch the heater to a conductive state when the element temperature of the heater falls below a return temperature lower than the operating temperature in the non-conductive state of the heater. The main switching element in this vehicle heater control device is disposed at a position separated from the heater and facing the interior of the vehicle compartment, and is electrically connected to the heater via a lead wire extending from the heater. The vehicle heater control device further includes an auxiliary switching element disposed over the heater, the auxiliary switching element being configured to switch the heater to a non-conductive state when the element temperature of the heater exceeds an overheat prevention temperature higher than the operating temperature in the conductive state of the heater. Effect of the Invention

[0011] According to one aspect of the vehicle heater control device of the present invention, the temperature around the heater is adjusted according to the temperature inside the vehicle cabin, thereby improving the comfort of the occupants even when the temperature inside the vehicle cabin changes. [Brief description of the drawings]

[0012] [Figure 1] 1 is an exploded perspective view showing a configuration example of a seat cushion to which a vehicle heater control device according to a first embodiment of the present invention is applied; [Diagram 2]FIG. 2 is a perspective view showing the appearance of the seat cushion in the first embodiment. [Diagram 3] FIG. 2 is a diagram showing an example of a circuit configuration of a seat heater in the first embodiment. [Figure 4] 4 is an enlarged side view showing a schematic diagram of a front portion of the seat heater shown in FIG. 3. [Diagram 5] 4 is a graph illustrating an example of the operation of the thermostat when the temperature inside the vehicle compartment is low in the first embodiment. [Figure 6] 4 is a graph illustrating an example of the operation of a thermostat when the temperature inside the vehicle compartment is high in the first embodiment. [Figure 7] 5 is a graph showing an example of changes over time in the temperature inside the vehicle compartment and the temperature of the seat in the first embodiment. [Figure 8] FIG. 6 is a diagram showing an example of a circuit configuration of a seat heater in a vehicle heater control device according to a second embodiment of the present invention. [Figure 9] FIG. 11 is a diagram showing an example of a circuit configuration of a seat heater in a vehicle heater control device according to a third embodiment of the present invention. [Figure 10] FIG. 13 is a diagram showing a modified example related to the third embodiment. [Figure 11] FIG. 11 is a block diagram showing a functional configuration of a vehicle heater control device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. [First embodiment] Fig. 1 is an exploded perspective view showing a configuration example of a seat cushion 2 to which a vehicle heater control device 1 according to a first embodiment of the present invention is applied. Fig. 2 is a perspective view showing the appearance of the seat cushion 2 in the first embodiment. In each of the drawings described below, the arrow F direction indicates the front in the vehicle longitudinal direction, and the arrow U direction indicates the upper side in the vehicle vertical direction. The arrow R direction and the arrow L direction indicate the right and left directions when looking at the front of the vehicle from inside the vehicle compartment.

[0014] 1 and 2, a vehicle heater control device 1 of the first embodiment controls the driving state of a seat heater 10 installed in a seat cushion 2 on which an occupant sits in a seat of a vehicle such as an automobile. The seat heater 10 spreads to cover a seating surface 2A and a front upper portion 2B of the seat cushion 2. A heating portion 11 is formed in a portion of the seat heater 10 corresponding to the seating surface 2A of the seat cushion 2, and a temperature adjustment portion 12 is formed in a portion of the seat heater 10 corresponding to the front upper portion 2B of the seat cushion 2. In the first embodiment, the seating surface 2A of the seat cushion 2 corresponds to the "vehicle member" of the present invention.

[0015] Specifically, the seat cushion 2 has a cushion material 21 on which the seat heater 10 is mainly placed on the upper surface, and a cushion cover 22 that covers the cushion material 21 and the seat heater 10 (FIG. 1). The cushion material 21 has elastic properties and serves as a base that forms the seat surface 2A of the seat cushion 2. The cushion material 21 is installed on the upper part of a cushion frame 23 that constitutes the skeleton of the seat cushion 2 (FIG. 2). The lower part of the cushion frame 23 is movably attached to left and right seat rails 24 via running parts (not shown) at both sides in the seat width direction. The seat rails 24 are provided on the floor of the vehicle interior and extend in the front-rear direction of the vehicle. A seat back (not shown) is pressed against the upper rear end of the cushion material 21 via the seat heater 10 and the cushion cover 22.

[0016] The cushion cover 22 is a trim that covers the cushion material 21 and the seat heater 10 from above (FIG. 1). The cushion cover 22 covers the upper part, front part, rear part, and both left and right sides of the cushion material 21. In other words, the seat cushion 2 is configured such that the seat heater 10 is interposed at a predetermined position between the cushion material 21 and the cushion cover 22. A material having high thermal conductivity or thermal transferability is used for the portions of the cushion cover 22 that correspond to at least the upper part and front part of the cushion material 21.

[0017] The seat heater 10 is interposed between the cushion material 21 and the cushion cover 22, and extends in the front-rear and left-right directions so as to cover the upper surface of the cushion material 21, and also curves downward to continuously cover from the upper surface of the cushion material 21 to the upper front surface and the left-right directions (broken line in FIG. 2). The seat heater 10 has a heating section 11 formed in a portion covering the upper surface of the cushion material 21, and a temperature adjustment section 12 formed in a portion covering the upper front surface of the cushion material 21. Power is supplied to the heating section 11 from the vehicle battery via an electric connector wiring 13.

[0018] The temperature adjustment unit 12 is disposed at a position away from the heat generating unit 11 and facing the interior of the vehicle. In the first embodiment, the temperature adjustment unit 12 is disposed below the front end line 2C of the seat cushion 2 shown by the dashed line in FIG. 2 and near the center line 2D in the seat width direction (left-right direction), and is configured to face the interior of the vehicle through a portion of the cushion cover 22 having high thermal conductivity or thermal transferability. The temperature adjustment unit 12 disposed in this manner is located between the left and right legs of an occupant seated on the seat cushion 2 in the seat width direction. Therefore, the temperature adjustment unit 12 is located at a position where the air in the vehicle interior can easily reach the temperature adjustment unit 12 without being blocked by the legs of the occupant. The temperature adjustment unit 12 is electrically connected to the heat generating unit 11 through a lead wire 14 extending from the heat generating unit 11 (FIG. 1).

[0019] Here, a specific configuration example of the seat heater 10 in the first embodiment will be described in detail with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram showing an example of a circuit configuration of the seat heater 10. Fig. 4 is an enlarged side view that typically shows a front portion of the seat heater 10 in Fig. 3.

[0020] As shown in Fig. 3 and Fig. 4, the seat heater 10 includes a base material 10A using a felt mat or the like, and heater wires 11A, 12A and a thermostat 12B disposed on the back surface (the surface on the cushioning material 21 side) of the base material 10A. Here, the heat generating unit 11 described above is constituted by the heater wire 11A, and the temperature adjusting unit 12 is constituted by the heater wire 12A and the thermostat 12B. The heater wire 11A of the heat generating unit 11 and the heater wire 12A and thermostat 12B of the temperature adjusting unit 12 are electrically connected via a lead wire 14. In the first embodiment, the heat generating unit 11 (heater wire 11A) corresponds to the "heater" of the present invention, and the thermostat 12B of the temperature adjusting unit 12 corresponds to the "main switching element" of the present invention.

[0021] The base material 10A of the seat heater 10 is formed in a trapezoid shape with the width at the front side of the seat wider than the width at the rear side of the seat, corresponding to the shape of the seat surface 2A and the upper front surface 2B of the seat cushion 2. The base material 10A has flexibility that allows it to form a curved surface along the surface shape of the cushion material 21 when attached to the seat cushion 2. The base material 10A also has high breathability, and here, an opening 10B is formed at the location of the base material 10A where the thermostat 12B is to be placed, thereby improving the thermal conductivity or thermal transferability of the base material 10A (FIG. 4). The thermostat 12B is fixed to the periphery of the opening 10B so as to close the opening 10B from the back side of the base material 10A, and the air in the vehicle cabin is ventilated to the surface of the thermostat 12B through the cushion cover 22 and the opening 10B. If the thermal conductivity or thermal transferability of the base material 10A is sufficiently high, the opening 10B can be omitted.

[0022] The heater wire 11A of the heating portion 11 is fixed to the rear surface of the base material 10A according to a wiring pattern that covers almost the entire seating surface 2A of the seat cushion 2. A power source 15 (vehicle battery) and a heater switch 16 are connected in series to the heater wire 11A via the above-mentioned electric connector wiring 13. The heater switch 16 is, for example, a switch installed on the instrument panel of the vehicle, and allows the seat heater 10 to be switched ON and OFF by manual operation by an occupant. The heater wire 11A generates heat when the heater switch 16 is turned ON and a current flows due to the electromotive force of the power source 15, thereby warming the seating surface 2A of the seat cushion 2.

[0023] Furthermore, the heater wire 11A of the heat generating unit 11 has a lead wire 14 extending from the front portion of its wiring pattern, and the heater wire 12A and thermostat 12B of the temperature adjusting unit 12 are connected in series to the lead wire 14. As described above, the power source 15 (vehicle battery), heater switch 16, electrical connector wiring 13, heater wire 11A of the heat generating unit 11, lead wire 14, and heater wire 12A and thermostat 12B of the temperature adjusting unit 12 are connected in order to form a series circuit as a whole (FIG. 3).

[0024] The heater wire 12A of the temperature control unit 12 is fixed to the rear surface of the substrate 10A and the front surface of the thermostat 12B according to a wiring pattern that covers the front surface of the thermostat 12B. One end of the heater wire 12A is connected to one of the two lead wires 14, and the other end of the heater wire 12A is connected to one terminal of the thermostat 12B. The other lead wire 14 is connected to the other terminal of the thermostat 12B.

[0025] The thermostat 12B is configured using, for example, a bimetal thermostat in which two or more metal plates with different coefficients of thermal expansion are bonded together. When the temperature (element temperature) Te of the thermostat 12B exceeds the operating temperature Tα (Te > Tα) in the conductive state of the series circuit including the heater wire 11A of the heating unit 11, the thermostat 12B switches the series circuit to a non-conductive state. Also, when the element temperature Te of the thermostat 12B falls below the return temperature Tβ (Te < Tβ < Tα) which is lower than the operating temperature Tα in the non-conductive state of the series circuit, the thermostat 12B switches the series circuit to a conductive state. The operating temperature Tα and the return temperature Tβ of the thermostat 12B are unique values determined by the temperature characteristics of elements such as the bimetal used. That is, the thermostat 12B functions as a switching element that switches from ON to OFF when the element temperature Te reaches the operating temperature Tα, and switches from OFF to ON when the element temperature Te drops to the return temperature Tβ.

[0026] Also, in the thermostat 12B of the first embodiment, as the temperature of the air in the vehicle interior (vehicle interior temperature) Tc increases, the degree of increase in the element temperature Te becomes larger and the degree of decrease becomes smaller. That is, when the vehicle interior temperature Tc increases and the temperature difference from the element temperature Te of the thermostat 12B becomes smaller, a phenomenon occurs where the amount of heat transfer per unit time from the thermostat 12B to the vehicle interior air becomes smaller, so the thermostat 12B is likely to warm up (the degree of increase in the element temperature Te is large) and difficult to cool down (the degree of decrease in the element temperature Te is small). In other words, when the vehicle interior temperature Tc decreases and the temperature difference from the element temperature Te of the thermostat 12B becomes larger, a phenomenon occurs where the amount of heat transfer per unit time from the thermostat 12B to the vehicle interior air becomes larger, so the thermostat 12B is difficult to warm up and easy to cool down. The element temperature Te of the thermostat 12B changes according to the vehicle interior temperature Tc when the series circuit is in a non-conductive state, and changes according to the vehicle interior temperature Tc and the amount of heat generated by the heater wire 12A when the series circuit is in a conductive state.

[0027] Specifically, the operation of the thermostat 12B in the first embodiment will be described in detail with reference to Fig. 5 and Fig. 6. Fig. 5 is a graph illustrating an example of the operation of the thermostat 12B when the vehicle interior temperature Tc is low. Fig. 6 is a graph illustrating an example of the operation of the thermostat 12B when the vehicle interior temperature Tc is high.

[0028] First, assume that the vehicle interior temperature Tc is low (e.g., -30°C). In this case, when the heater switch 16 is turned on to activate the seat heater 10, the element temperature Te of the thermostat 12B is lowered to approximately the same temperature as the vehicle interior temperature Tc. Therefore, the element temperature Te is lower than both the operating temperature Tα (e.g., 36°C) and the return temperature Tβ (e.g., 25°C) of the thermostat 12B.

[0029] In this low-temperature state immediately after startup, thermostat 12B turns on the series circuit including heater wire 12A of temperature control unit 12. As a result, current I flowing through heater wire 12A of temperature control unit 12 becomes a predetermined value Ion, and heater wire 12A generates heat, as shown in the lower part of Fig. 5. Due to the heat generated by heater wire 12A, element temperature Te of thermostat 12B rises at a constant rate over time, as shown in the upper part of Fig. 5.

[0030] The current I=Ion also flows through the heater wire 11A of the heat generating unit 11, so the seat surface temperature of the seat cushion 2 also rises. However, even if the seat surface temperature and the element temperature Te rise due to the heat generated by the heater wires 11A and 12A, the temperature Tc inside the vehicle compartment remains low with almost no change unless the vehicle compartment is heated by an air conditioner or the like. This is because the heat capacity of the air inside the vehicle compartment is much larger than the heat capacity of the seat cushion 2 and the thermostat 12B.

[0031] When the element temperature Te of thermostat 12B reaches operating temperature Tα due to heat generation from heater wire 12A of temperature adjustment unit 12, thermostat 12B switches the series circuit to a non-conducting state. This causes the current I flowing through heater wire 12A to become zero (Ioff). When heater wire 12A stops generating heat, the interior temperature Tc of the vehicle is much lower than the operating temperature Tα, so the element temperature Te of thermostat 12B, which is located facing the interior of the vehicle, begins to decrease at a certain rate over time.

[0032] When the element temperature Te of thermostat 12B falls below the return temperature Tβ, thermostat 12B switches the series circuit to a conductive state, and current I=Ion flows through heater wire 12A, causing the element temperature Te of thermostat 12B to rise again at a constant rate. Then, when the element temperature Te of thermostat 12B reaches operating temperature Tα, thermostat 12B switches the series circuit to a non-conductive state, and current I flowing through heater wire 12A becomes zero (Ioff), causing the element temperature Te of thermostat 12B to fall again at a constant rate. In this way, in thermostat 12B, the above series of operations are repeated according to the relationship of element temperature Te to operating temperature Tα and return temperature Tβ (FIG. 5).

[0033] Next, assume that the vehicle interior temperature Tc is high (e.g., 25°C). In this case, when the heater switch 16 is turned on and the seat heater 10 is activated, the element temperature Te of the thermostat 12B is in a high temperature state that is approximately the same as the vehicle interior temperature Tc. Since this element temperature Te is lower than the operating temperature Tα of the thermostat 12B (e.g., 36°C), the thermostat 12B turns on the series circuit including the heater wire 12A of the temperature adjustment unit 12. As a result, as shown in the lower part of FIG. 6, the current I flowing through the heater wire 12A becomes a predetermined value Ion, and the heater wire 12A generates heat. Due to the heat generated by the heater wire 12A, the element temperature Te of the thermostat 12B rises at a certain rate over time, as shown in the upper part of FIG. 6. At this time, the degree of increase in the element temperature Te over time is greater than the degree of increase in the element temperature Te when the vehicle interior temperature Tc is low, because the vehicle interior temperature Tc is high. In other words, when the vehicle interior temperature Tc becomes relatively high, the thermostat 12B becomes easier to warm up.

[0034] When the element temperature Te of the thermostat 12B reaches the operating temperature Tα, the thermostat 12B switches the series circuit to a non-conducting state. This causes the current I flowing through the heater wire 12A to become zero (Ioff), and the heater wire 12A stops generating heat. When the heater wire 12A stops generating heat, the interior temperature Tc is lower than the operating temperature Tα, so the element temperature Te of the thermostat 12B, which is disposed at a position facing the interior of the vehicle, starts to decrease at a certain rate over time. At this time, the degree of decrease in the element temperature Te over time is smaller than the degree of decrease in the element temperature Te when the interior temperature Tc is low, because the interior temperature Tc is high. In other words, when the interior temperature Tc becomes relatively high, the thermostat 12B becomes difficult to cool down.

[0035] When the element temperature Te of thermostat 12B falls below return temperature Tβ, thermostat 12B switches the series circuit to a conductive state, and current I=Ion flows through heater wire 12A, causing the element temperature Te of thermostat 12B to rise again at a constant rate. Then, when the element temperature Te of thermostat 12B reaches operating temperature Tα, thermostat 12B switches the series circuit to a non-conductive state, and current I flowing through heater wire 12A becomes zero (Ioff), causing the element temperature Te of thermostat 12B to fall again at a constant rate (FIG. 6).

[0036] Since the thermostat 12B operating as described above and the heater wire 11A of the heat generating unit 11 are connected in series, the higher the vehicle interior temperature Tc, the more the amount of power supplied to the heater wire 11A of the heat generating unit 11 can be reduced. That is, the amount of power obtained by integrating the current I over time when the vehicle interior temperature Tc is low (corresponding to the area surrounded by the graph of current I and the time axis shown in FIG. 5) is less than the amount of power obtained by integrating the current I over time when the vehicle interior temperature Tc is high. This makes it possible to realize, by an electric circuit using the thermostat 12B, control for lowering the seat surface temperature of the seat cushion 2 as the vehicle interior temperature Tc becomes higher.

[0037] FIG. 7 is a graph showing an example of changes over time in the vehicle interior temperature Tc and the seat surface temperature Ts in the first embodiment. In the example of Fig. 7, at time t0, the heater switch 16 is turned on to activate the seat heater 10 and start the heating operation of the air conditioner. The vehicle interior temperature Tc shown in the graph in the lower part of Fig. 7 gradually rises from time t0 to t2 due to heating, then drops temporarily from time t2 to t3 due to passengers getting in and out of the vehicle, begins to rise again from time t3 to t4, and is kept at a constant temperature after time t4 has passed.

[0038] With respect to such a change in the vehicle interior temperature Tc over time, the seat surface temperature Ts of the seat cushion 2 shown in the graph at the top of Fig. 7 is at a low temperature similar to the vehicle interior temperature Tc=X0 when the heater is turned on at time t0, and as described above, the thermostat 12B turns on the series circuit. This causes a current I=Ion to flow through the heater wire 11A of the heat generating unit 11, and the seat surface temperature Ts rises sharply due to the heat generated by the heater wire 11A, and at time t1, the seat surface temperature Ts reaches Y1. At this point, the element temperature Te of the thermostat 12B begins to repeatedly rise and fall between the operating temperature Tα and the return temperature Tβ, and the rapid rise in the seat surface temperature Ts converges.

[0039] Between times t1 and t2, as the vehicle interior temperature Tc rises from X1 to X2 due to heating, the amount of power supplied to the heater wire 11A of the heat generating unit 11 decreases as described above, causing the seat temperature Ts to gradually drop from Y1 to Y2. Between times t2 and t3, as the vehicle interior temperature Tc drops from X2 to X3 due to passengers getting in and out of the vehicle, the amount of power supplied to the heater wire 11A starts to increase, causing the seat temperature Ts to rise from Y2 to Y3.

[0040] Between times t3 and t4, as the vehicle interior temperature Tc rises from X3 to X4 due to heating, the amount of power supplied to the heater wire 11A starts to decrease again, causing the seating surface temperature Ts to gradually decrease from Y3 to Y4. After time t4, the vehicle interior temperature Tc is maintained at X4, and the seating surface temperature Ts is also maintained at Y4.

[0041] As described above, in the vehicle heater control device 1 of the first embodiment, the thermostat 12B of the temperature adjustment unit 12 in the seat heater 10 is disposed at a position facing the vehicle interior, away from the heat generating unit 11 that heats the seating surface 2A of the seat cushion 2, and is electrically connected to the heater wire 11A of the heat generating unit 11 via the lead wire 14 extending from the heat generating unit 11. By using such a thermostat 12B to switch the heat generating unit 11 between a conductive state and a non-conductive state, the seating surface temperature Ts of the seat cushion 2 can be automatically adjusted according to the vehicle interior temperature Tc. Therefore, it is possible to improve the comfort of the occupant even when the vehicle interior temperature Tc changes.

[0042] In the vehicle heater control device 1 of the first embodiment, as the vehicle interior temperature Tc increases, the degree of increase in the element temperature Te of the thermostat 12B increases and the degree of decrease decreases. In this way, by utilizing the phenomenon that the ease of heating and cooling changes depending on the difference between the vehicle interior temperature Tc and the element temperature Te of the thermostat 12B, it is possible to realize control to lower the seat surface temperature Ts as the vehicle interior temperature Tc increases. This makes it possible to suppress the occupant from feeling that the seat surface 2A of the seat cushion 2 is too hot even when the vehicle interior temperature Tc is high, thereby further improving the comfort of the occupant in the vehicle interior. In addition, the higher the vehicle interior temperature Tc, the longer it takes for the element temperature Te to fall below the limit temperature Tβ, so the time during which the power supplied to the heater wire 11A of the heat generating unit 11 is limited becomes longer. This makes it possible to extend the interval at which the heater wire 11A is repeatedly turned on and off, thereby further improving the comfort of the occupant and reducing the amount of power consumption.

[0043] In the above first embodiment, an example was described in which the ease of heating and cooling changes depending on the difference between the vehicle interior temperature and the thermostat temperature, thereby realizing control to lower the seat temperature as the vehicle interior temperature increases. However, similar control can also be achieved even if the thermostat 12B itself has the characteristic of being easy to heat and difficult to cool.

[0044] [Second embodiment] Next, a vehicle heater control device according to a second embodiment of the present invention will be described. In the second embodiment, for example, an application example in which an overheating prevention thermostat is provided in addition to the thermostat 12B of the temperature adjustment unit 12 in the above-mentioned first embodiment to prevent the seat surface temperature Ts of the seat cushion 2 from rising too high will be described.

[0045] 8 is a diagram showing an example of a circuit configuration of a seat heater 10 in a vehicle heater control device 1 of the second embodiment. In the following description, the same reference numerals as those in the first embodiment above indicate the same or corresponding parts. In Fig. 8, the configuration of the vehicle heater control device 1 of the second embodiment differs from that of the first embodiment in that an overheat prevention thermostat 17 is provided in the heat generating portion 11 of the seat heater 10. The configuration of the vehicle heater control device 1 of the second embodiment other than the above differences is the same as that of the first embodiment, so a description thereof will be omitted here. In the second embodiment, the overheat prevention thermostat 17 corresponds to the "auxiliary switching element" of the present invention.

[0046] The overheating prevention thermostat 17 is inserted in series onto the heater wire 11A of the heat generating portion 11, and is disposed at a position overlapping with part of the wiring pattern of the heater wire 11A. Here, the overheating prevention thermostat 17 is fixed to the back surface of the base material 10A of the seat heater 10 so that the overheating prevention thermostat 17 is disposed at the rear part of the seat surface 2A of the seat cushion 2, toward the left of the center in the seat width direction.

[0047] When the element temperature Te' of the series circuit including the heater wire 11A is in a conductive state, the overheat prevention thermostat 17 switches the series circuit to a non-conductive state when the element temperature Te' exceeds the overheat prevention temperature Tα'. The overheat prevention temperature Tα' of the overheat prevention thermostat 17 is set to a value higher than the operating temperature Tα of the thermostat 12B of the temperature adjustment unit 12 described above. As a specific example of the overheat prevention temperature Tα', it can be set to a temperature (e.g., 45°C) at which an occupant sitting on the seat cushion 2 is unlikely to suffer low-temperature burns. The return temperature Tβ' of the overheat prevention thermostat 17 is set to a temperature (e.g., 36°C) equivalent to human body temperature at which an occupant does not feel cold or hot when touching the seat surface 2A.

[0048] In the vehicle heater control device 1 of the second embodiment as described above, the overheat prevention thermostat 17 performs switching operation according to the temperature around the heater wire 11A of the heat generating unit 11, independently of the operation of the thermostat 12B of the temperature adjusting unit 12. If the seat surface temperature Ts of the seat cushion 2 becomes higher than the overheat prevention temperature Tα' for some reason, the overheat prevention thermostat 17 cuts off the current I flowing through the heater wire 11A of the heat generating unit 11. As a result, the heater wire 11A does not generate heat when overheating occurs, so it is possible to prevent the seat surface 2A of the seat cushion 2 from becoming too hot and causing discomfort to the occupant.

[0049] [Third embodiment] Next, a vehicle heater control device according to a third embodiment of the present invention will be described. In the third embodiment, for example, a modified example in which the temperature adjustment unit 12 provided inside the seat heater 10 in the above-described first embodiment is provided outside the seat heater 10 will be described.

[0050] Fig. 9 is a diagram showing an example of a circuit configuration of a seat heater 10 in a vehicle heater control device 1 of a third embodiment. As shown in Fig. 9, in the seat heater 10 of the third embodiment, only the heater wire 11A of the heat generating unit 11 that heats the seat surface 2A of the seat cushion 2 is provided on the back surface of the base material 10A. As in the case of the first embodiment described above, a power source 15 and a heater switch 16 are connected in series to the heater wire 11A of the heat generating unit 11 via an electric connector wiring 13. A lead wire 14 extends from the wiring connecting the electric connector wiring 13 and the heater switch 16, and a heater wire 12A and a thermostat 12B of a temperature adjustment unit 12 are connected in series to the lead wire 14.

[0051] The heater wire 12A and thermostat 12B of the temperature adjustment unit 12 are installed outside the seat heater 10, specifically, for example, on the bottom surface, right side surface or left side surface of the seat cushion 2, the rear surface of the seat back, the floor inside the vehicle compartment, the instrument panel, or the console box. The temperature adjustment unit 12 is also installed at a position away from the heat generating unit 11 of the seat heater 10 and facing the inside of the vehicle compartment. In the vehicle heater control device 1 of the third embodiment, the configuration is the same as that of the first embodiment described above, except that the temperature adjustment unit 12 is provided outside the seat heater 10, and therefore a description thereof will be omitted here.

[0052] According to the vehicle heater control device 1 of the third embodiment as described above, the heater wire 12A and thermostat 12B of the temperature adjustment unit 12 are separate components from the heat generating unit 11 of the seat heater 10, so that the temperature characteristics of the thermostat 12B can be easily changed by replacing these components, and design freedom regarding the installation location of the temperature adjustment unit 12 can be increased.

[0053] In the third embodiment, an example was shown in which the temperature adjustment unit 12, which is a separate component, includes one thermostat 12B. However, as shown in FIG. 10, it is also possible to selectively use a plurality of thermostats 12B having different characteristics by connecting them in parallel. In the modified example of FIG. 10, three sets of circuit units, each of which has a heater wire 12A and a switch 12C connected in series to three thermostats 12B having different characteristics, are connected in parallel between the lead wires 14. When the temperature adjustment unit 12 is in operation, the switch 12C corresponding to the thermostat 12B having the desired characteristics is turned ON, and the remaining switches 12C are turned OFF. According to such a circuit configuration of the temperature adjustment unit 12, the control characteristics of the seat surface temperature Ts according to the vehicle interior temperature Tc can be appropriately switched according to the preference of the occupant, so that the comfort of the occupant can be further improved.

[0054] [Fourth embodiment] Next, a vehicle heater control device according to a fourth embodiment of the present invention will be described. In the fourth embodiment, for example, an application example in which a function equivalent to the temperature adjustment unit 12 in the above-mentioned first to third embodiments is realized without using a thermostat will be described.

[0055] FIG. 11 is a block diagram showing a functional configuration of a vehicle heater control device 1 according to the fourth embodiment. 11, the vehicle heater control device 1 of the fourth embodiment includes a switch circuit 31 that switches between a conductive state and a non-conductive state of the heater wire 11A of the seat heater 10, and a switch control unit 32 that controls the operation of the switch circuit 31. In the fourth embodiment, the switch circuit 31 corresponds to the "switching element" of the present invention, and the switch control unit 32 corresponds to the "control means" of the present invention.

[0056] The switch circuit 31 is inserted on the wiring connecting the electric connector wiring 13 of the seat heater 10 and the heater switch 16, similar to the third embodiment described above. When the heater switch 16 is in the ON state, the switch circuit 31 switches between conduction (ON) and non-conduction (OFF) of the current I flowing through the heater wire 11A of the seat heater 10 by the electromotive force of the power source 15. Note that, although an example in which the switch circuit 31 is provided separately from the heater switch 16 has been shown here, it is also possible to use a common circuit for the heater switch 16 and the switch circuit 31.

[0057] The switch control unit 32 controls ON / OFF of the switch circuit 31 based on the vehicle interior temperature Tc detected by the vehicle interior temperature sensor 33 and the seat surface temperature Ts detected by the seat surface temperature sensor 34. The vehicle interior temperature sensor 33 is installed, for example, on the instrument panel of the vehicle, and detects the temperature of the air in the vehicle interior and transmits it to the switch control unit 32. An air conditioning temperature sensor (not shown) installed in the vehicle may also be used as the vehicle interior temperature sensor 33. The seat surface temperature sensor 34 is installed near the seat heater 10, and detects the temperature around the seat heater 10 (the seat surface 2A of the seat cushion 2) and transmits it to the switch control unit 32.

[0058] When the vehicle interior temperature Tc detected by the vehicle interior temperature sensor 33 exceeds a predetermined limit temperature Ta, the switch control unit 32 controls the switch circuit 31 so as to limit the power supplied to the heater wire 11A of the seat heater 10. The limit temperature Ta corresponds to the operating temperature Tα of the thermostat 12B of the temperature adjustment unit 12 in the above-mentioned first to third embodiments. Here, the power is limited by relatively lengthening the time during which the switch circuit 31 is in the OFF state to shorten the current supply time. Note that the power can be limited by reducing the amount of current (the current value I passed through the heater wire 11A) in addition to shortening the current supply time.

[0059] Furthermore, the switch control unit 32 controls the switch circuit 31 so that the power restriction is lifted when the vehicle interior temperature Tc falls below a predetermined release temperature Tb. The release temperature Tb corresponds to the return temperature Tβ of the thermostat 12B of the temperature adjustment unit 12 in the first to third embodiments described above.

[0060] When limiting or releasing the power supply to the heater wire 11A of the seat heater 10 as described above, the switch control unit 32 controls the switch circuit 31 so that the amount of power limitation is changed based on the vehicle interior temperature Tc detected by the vehicle interior temperature sensor 33 and the seat temperature (heater ambient temperature) Ts detected by the seat temperature sensor 34.

[0061] Specifically, the switch control unit 32 in the fourth embodiment controls the switch circuit 31 so that the smaller the difference between the vehicle interior temperature Tc and the seat surface temperature Ts, the greater the amount of power restriction. In other words, the switch control unit 32 controls the switch circuit 31 so that the larger the difference between the vehicle interior temperature Tc and the seat surface temperature Ts, the less the amount of power restriction. In other words, the switch control unit 32 controls the switch circuit 31 so that the time during which current is applied to the heater wire 11A becomes shorter as the vehicle interior temperature Tc rises and approaches the seat surface temperature Ts, and the time during which current is applied to the heater wire 11A becomes longer as the vehicle interior temperature Tc falls and moves away from the seat surface temperature Ts. In addition to the control of the amount of power restriction according to the difference between the vehicle interior temperature Tc and the seat surface temperature Ts as described above, the amount of power restriction may be increased when the vehicle interior temperature Tc is higher than a predetermined value.

[0062] In the vehicle heater control device 1 of the fourth embodiment as described above, the operation of the switch circuit 31 that switches the conductive state and non-conductive state of the heater wire 11A of the seat heater 10 is controlled by the switch control unit 32 based on the vehicle interior temperature Tc and the seat surface temperature Ts, thereby limiting the power supplied to the heater wire 11A. This suppresses the rise in the seat surface temperature Ts caused by the heat generated by the heater wire 11A according to the vehicle interior temperature Tc, thereby preventing the occupant from feeling that the seat surface 2A is too hot, thereby improving comfort. In particular, if the switch control is performed to change the amount of power limit according to the difference between the vehicle interior temperature Tc and the seat surface temperature Ts, the seat surface temperature Ts can be appropriately adjusted according to the change in the vehicle interior temperature Tc, thereby further improving the comfort of the occupant.

[0063] Although the first to fourth embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned first to fourth embodiments, and various modifications and changes are possible based on the technical concept of the present invention. For example, in each of the above-mentioned embodiments, an example in which the heat generating portion 11 (heater wire 11A) of the seat heater 10 provided in the seat cushion 2 is the control target has been described, but the control target may be a heater provided in a vehicle member that comes into contact with an occupant, such as a seat back, an ottoman, a footrest, a headrest, an armrest, or a steering wheel. [Explanation of symbols]

[0064] 1...Vehicle heater control device 10…Seat heater 10A…Base material 10B…Aperture 11... Heater 11A…Heater wire 12...Temperature control section 12A…Heater wire 12B…Thermostat (main switching element) 13…Electrical connector wiring 14…Leader line 15...Power supply 16…Heater switch 17...Thermostat for overheating prevention (auxiliary switching element) 2. Seat cushion 2A…Seat (vehicle component) 2B…Top front 2C…Front line 2D…Center line 21…Cushioning material 22...Cushion cover 23…Cushion frame 24…Seat rail 31...Switch circuit (switching element) 32...Switch control section (control means) 33…Vehicle interior temperature sensor 34…Seat temperature sensor Ta: Limit temperature Tb…Release temperature Tc…Indoor temperature Te, Te': Element temperature Ts…Seat temperature (temperature around heater) Tα…Operating temperature Tα'...Overheating prevention temperature Tβ, Tβ': Recovery temperature

Claims

1. a main switching element for switching between a conductive state and a non-conductive state of a heater that generates heat when conductive to warm vehicle members; a main switching element configured to switch the heater to a non-conductive state when an element temperature of the main switching element exceeds an operating temperature in a conductive state of the heater, and to switch the heater to a conductive state when the element temperature of the main switching element falls below a return temperature that is lower than the operating temperature in a non-conductive state of the heater, the main switching element is disposed at a position separated from the heater and facing the interior of the vehicle compartment, and is electrically connected to the heater via a lead wire extending from the heater; Further comprising an auxiliary switching element disposed over the heater, a switching element configured to switch the heater to a non-conductive state when the element temperature exceeds an overheat prevention temperature that is higher than the operating temperature while the heater is in a conductive state.

2. a main switching element for switching between a conductive state and a non-conductive state of a heater that generates heat when conductive to warm vehicle members; a main switching element configured to switch the heater to a non-conductive state when an element temperature of the main switching element exceeds an operating temperature in a conductive state of the heater, and to switch the heater to a conductive state when the element temperature of the main switching element falls below a return temperature that is lower than the operating temperature in a non-conductive state of the heater, The main switching element is disposed at a position separated from the heater and facing the interior of the vehicle cabin, and is electrically connected to the heater via a lead wire extending from the heater, and as the interior temperature of the vehicle cabin, which indicates the temperature of the air inside the vehicle cabin, increases, the rate of increase in the element temperature increases and the rate of decrease in the element temperature decreases.

3. a switching element for switching between a conductive state and a non-conductive state of a heater that generates heat when conductive to warm vehicle components; a control means for controlling the switching element so that power supplied to the heater is limited when an interior temperature indicating an air temperature inside the vehicle compartment exceeds a limit temperature, and for controlling the switching element so that the power limit is released when the interior temperature falls below a release temperature, The control means controls the switching element so that the amount of power limitation is changed based on the vehicle interior temperature and a heater surrounding temperature indicating the temperature around the heater.

4. 4. The vehicle heater control device according to claim 3, wherein the control means controls the switching element so that the amount of power restriction increases as the difference between the vehicle interior temperature and the heater surrounding temperature decreases.

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