JP2012136154A - Vehicle heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle heating device that is capable of improving the efficiency of heat transfer and the durability.SOLUTION: The vehicle heating device includes a heat transfer block 4 having an insertion hole 28 for receiving an electric wire heater 2, and a flow path 6 where a heat medium heated by heating the electric wire heater 2 flows. The electric wire heater 2 is fitted into the insertion hole 28 by a shrink fit. The interference of the shrink fit is ≥10 μm.

Description

  The present invention relates to a vehicle heating device.

  In this type of heating device, a flat heat transfer body is formed by burying a flow pipe through which hot water as a heat medium circulates and a heating wire heater arranged in parallel with the flow pipe in a heat transfer metal. There is known a structure in which a plurality of the heat transfer bodies are formed and the flow pipes are connected in series and configured as a heat source device (see, for example, Patent Document 1).

JP 2003-48422 A

  Recently, the development and spread of hybrid vehicles and electric vehicles has been promoted, and the waste heat of the engine can no longer be used in the future. Therefore, the heating device using the heating wire heater as described above is mounted on the vehicle. It is possible. In the case of a hybrid vehicle, the refrigeration circuit of the vehicle air conditioner is used as an auxiliary heat source that can supply heat to supplement the waste heat of the engine, and in the case of an electric vehicle, as an alternative heat source that can supply heat instead of the engine. It is expected to be used for heating circulating refrigerants.

However, in the above prior art, regarding the effect of the material structure level gap between the housing hole for housing the heating wire heater and the heating wire heater in the heat transfer block, which is a heat transfer body, on the heat transfer efficiency and durability of the device No particular consideration has been given, and there are still problems in improving the heat transfer efficiency and durability of the heating device.
The present invention has been made based on the above-described circumstances, and an object thereof is to provide a vehicle heating apparatus that can improve heat transfer efficiency and durability.

In order to achieve the above object, a vehicle heating apparatus according to claim 1 of the present invention includes a heat transfer block having an insertion hole in which a heating wire heater is accommodated, and a flow path through which a heat medium heated by the heating wire heater flows. The heating wire heater is fitted into the insertion hole by shrink fitting.
The invention described in claim 2 is characterized in that the interference fit is 10 μm or more.

  According to the vehicle heating device of the first aspect, the heating wire heater and the insertion hole are brought into close contact with each other by fitting the heating wire heater into the insertion hole by shrink fitting. The gap at the material structure level can be reduced. Accordingly, it is possible to reduce the thermal resistance due to the presence of the air layer between the heating wire heater and the heat transfer block, and to reduce the temperature gap generated between the heating wire heater and the heat transfer block. Therefore, the heat transfer efficiency of the heating device can be improved.

Further, the heat gap in the heating wire heater, which is generated as a result of hindering the heat transfer from the heating wire heater to the heat transfer block and thus to the heat medium flowing through the flow path due to the large temperature gap, can be suppressed. Therefore, it is possible to prevent the heating wire heater from being abnormally heated and thermally deteriorated, and it is possible to improve the durability of the heating wire heater and thus the heating device.
Furthermore, since it is not necessary to provide an adhesive for fixing the heating wire heater to the insertion hole or a heat conducting material for improving heat transfer efficiency in the gap between the heating wire heater and the insertion hole, these adhesive and heat It is possible to prevent the heat transfer efficiency from being lowered due to thermal deterioration of the conductive material.

  According to the invention of claim 2, specifically, the clearance of the shrink fit is 10 μm or more, so that the gap in the material structure level between the heating wire heater and the heat transfer block is reduced, and the heating device Heat transfer efficiency and durability can be effectively improved.

It is the perspective view which sees through and showed the side surface of the outer side case of the heating apparatus which concerns on one Embodiment of this invention. It is a perspective longitudinal cross-sectional view of the heating wire heater of FIG. 1, and a figure which shows the external connection. It is a perspective view of the heat-transfer block of FIG. It is a longitudinal cross-sectional view of the outer case of FIG. It is a perspective view of the outer case of FIG. It is a longitudinal cross-sectional view of the outer case of FIG. It is the figure which showed the flow of the heat medium in the heating apparatus of FIG. It is the figure which showed notionally the gap | interval of the material structure level of the heating wire heater of FIG. 1, and an insertion hole. It is the figure which showed the relationship between the clearance gap of FIG. 8, and heater internal temperature. It is the figure which showed the temperature distribution in the heat-transfer block of FIG. It is the figure which showed the time-sequential change of the temperature distribution of FIG.

1 to 7 show a vehicle heating apparatus 1 according to an embodiment of the present invention.
As shown in FIG. 1, the heating device 1 includes a heat transfer block 4 in which four heating wire heaters 2 are accommodated, and the heat transfer block 4 is accommodated between the heat transfer blocks 4. It is comprised from two units with the outer side case 8 which forms the flow path 6 through which a medium flows.
The heating device 1 is mounted on a vehicle such as a hybrid vehicle or an electric vehicle, for example. In the case of a hybrid vehicle, as an auxiliary heat source for supplying heat so as to compensate for waste heat that the engine lacks, As an alternative heat source for supplying heat in place of a non-existing engine, it is used for heating a refrigerant circulating in a refrigeration circuit of a vehicle air conditioner.

  Specifically, in the case of a hybrid vehicle, LLC (cooling water, antifreeze liquid) circulating in the cooling water circuit to cool the engine in the flow path 6 flows as a heat medium and is heated by the heating wire heater 2. This cooling water circuit is provided in the vehicle air conditioner, and the heat of the LLC heated by the engine and the heating device 1 is used to heat the refrigerant circulating in the refrigeration circuit provided in the air conditioner. It becomes possible.

  On the other hand, in the case of an electric vehicle, the refrigerant circulating in the refrigeration circuit flows through the flow path 6 as a heat medium and is heated by the heating wire heater 2. This refrigeration circuit is provided in the vehicle air conditioner in the same manner as described above, and the interior and exterior of the vehicle compartment can be cooled and heated by the heat of the refrigerant heated by the heating device 1. Further, water as a heat medium is circulated through the flow path 6, the water is heated by the heating wire heater 2, and the refrigerant circulating through the heating circuit of the vehicle air conditioner is heated using this hot water as an alternative heat source for the engine. It can also be used as a heat source for this purpose.

Further, in both cases of a hybrid vehicle and an electric vehicle, a heating device 1 is provided together with a heater core (not shown) in a heating circuit in which the antifreeze liquid circulates, and the heating device 1 is used as one of the heat sources of the antifreeze liquid and is heated by the heater core. It is also conceivable to blow air.
As shown in FIG. 2, the heating wire heater 2 is formed by inserting a coiled heating wire 12 such as a nichrome wire into a bottomed cylindrical metal pipe 10 made of, for example, stainless steel (SUS). The heat-resistant insulating material 14 having high electrical insulation and thermal conductivity is press-filled and the heating wire 12 is enclosed. The heat resistant insulating material 14 is, for example, magnesium oxide (MgO), and the main body of the heating wire heater 2 including the heat resistant insulating material 14 and the metal pipe 10 has a heat resistant temperature of about 1100 ° C.

  A terminal portion 16 is provided in the opening of the metal pipe 10, and the terminal portion 16 has a terminal 18 that is connected to the heating wire 12 and protrudes from the heating wire heater 2. Each terminal 18 of each heating wire heater 2 is electrically connected to an external power supply device 20 and constitutes an energization circuit 22 for energizing the heating wire 12. The terminal portion 16 is formed of silicon or glass at the opening of the metal pipe 10, and the terminal portion 16 has a heat resistant temperature of about 200 ° C. to 300 ° C.

  In addition, each heating wire 12 of each heating wire heater 2 is provided with a current fuse (not shown) to protect each energizing circuit 22 from a large current exceeding the rating flowing through the heating wire 12, Prevents ignition. Further, a temperature sensor 24 such as a thermistor for detecting the temperature of the heat medium in the flow path 6 is disposed in the vicinity of each heating wire heater 2.

  Each temperature sensor 24 is electrically connected to an external electronic control unit (ECU) 26 that comprehensively controls the vehicle, and the power supply device 20 is also electrically connected to the ECU 26. The ECU 26 is connected to each of the four heating wire heaters 2 or to a plurality of terminals 16 in accordance with the temperature of the heat medium in each flow path 6 detected by each temperature sensor 24 via the power supply device 20. On the other hand, energization control for energizing individually is performed.

  As shown in FIGS. 3 and 4, the heat transfer block 4 is formed as a single unit by casting an aluminum (Al) alloy having a heat resistance temperature of about 400 ° C. and high thermal conductivity, for example. Yes. On the end face 4a of the heat transfer block 4, there are formed block opening end portions 30 in which four insertion holes 28 for accommodating the heating wire heaters 2 are gathered and opened at substantially equal intervals in the end face 4a.

  A flange-like flange portion 4c is formed over the entire circumference of the block opening end portion 30, and bolt insertion holes 32 are formed through the four corners of the flange portion 4c. Further, on the side surface 4 b of the heat transfer block 4, a convex guide 34 is integrally formed with the heat transfer block 4 so as to guide and flow the heat medium from an inlet port 40 to an outlet port 42 described later. Two guides 34 are provided by alternately shifting the height in the direction perpendicular to the longitudinal direction of the heating wire heater 2.

  On the other hand, as shown in FIGS. 5 and 6, the outer case 8 is integrally formed as one unit by casting metal, for example, and can accommodate the heat transfer block 4, and the side surface of the heat transfer block 4. 4b and the inner surface 8a of the outer case 8 have a volume capable of forming a gap constituting the flow path 6 of the heat medium. A case opening end portion 36 having an opening hole 8e for inserting the heat transfer block 4 is formed on the end surface 8b of the outer case 8 on the side where the heat transfer block 4 is accommodated.

  The case opening end portion 36 is formed in a size that allows the heat transfer block 4 to be inserted into the outer case 8, and the back surface 4 d of the flange portion 4 c covers the entire circumference in a state where the heat transfer block 4 is accommodated in the outer case 8. And has a shape that comes into contact with the case opening end 36. Bolt holes 38 are formed at the four corners of the case opening end 36 at positions that match the bolt insertion holes 32 in a state where the heat transfer block 4 is accommodated in the outer case 8. That is, the flange portion 4c is bolted and joined to the case opening end portion 36 so that the heat transfer block 4 and the outer case 8 are joined only at the respective opening end portions 30 and 36, in other words, heat transfer. The block 4 is fixed to the outer case 8 in a non-contact state except for the case opening end portion 36.

  Further, when the side surface 8c of the outer case 8 is on the case opening end 36 side, that is, in the state where the heat transfer block 4 is accommodated in the outer case 8, the heat medium inlet port 40 is formed in a pipe shape at the end on the terminal portion 16 side. It is projecting. On the other hand, at the end of the side surface 8c of the outer case 8 opposite to the case opening end portion 36, on the side of the bottom portion 8d, the outlet portion 42 of the heat medium projects in a pipe shape substantially diagonally to the inlet portion 40 of the side surface 8c. It is installed. That is, the inlet port 40 and the outlet port 42 are respectively provided in the vicinity of each apex that forms a diagonal in the longitudinal direction of the side surface 8c.

  As shown in FIG. 7, two guides 34 are provided by alternately shifting the height in the direction perpendicular to the longitudinal direction of the heating wire heater 2. Specifically, the guide 34 on the front side as viewed in FIG. 7 is provided. The height of the guide 34 on the back side opposite to the front side is lowered when the height of the guide 34 on the back side is higher than the height of the guide 34 on the one side. When the height is lower than the height of the guide 34 on the back side, the height is increased. As a result, as shown by solid line arrows and broken line arrows in FIG. 7 (the flow of the heat medium on the back side of the heat transfer block 4 is indicated by broken line arrows), the heat medium flows along the guides 34 of the heating wire heater 2. It flows through the flow path 6 while meandering in the longitudinal direction, that is, from the inlet port 40 toward the outlet port 42.

  FIG. 8 is an enlarged view conceptually showing the gap C at the material structure level between the heating wire heater 2 and the insertion hole 28 as viewed from the direction A in FIG. In this embodiment, the hole diameter d of each insertion hole 28 is formed at least 10 μm or more, preferably about 30 to 40 μm smaller than the outer diameter D of each metal pipe 10, that is, each heating wire heater 2. Is fitted in the insertion hole 28 in close contact by shrink fitting.

  Shrink fit is a kind of shrink fit. Inner member that is cooled and shrunk in a state where heat transfer block 4 that is an outer member is expanded by heating at a shrink fit heating temperature of about 150 to 250 ° C. The heating wire heater 2 is inserted into the insertion hole 28. And by leaving it to stand in this state and cooling to room temperature, the heating wire heater 2 can be fitted into the insertion hole 28 with an interference fit corresponding to an interference of at least 10 μm, preferably about 30 to 40 μm. . In the case of this embodiment, it is known that when the interference is 50 μm or more, the heating wire heater 2 cannot be inserted into the insertion hole 28 and the size of the interference is limited.

  On the outer surface 10a of the SUS metal pipe 10 and the inner surface 28a of the insertion hole 28 formed in the heat transfer block 4 made of aluminum alloy, unevenness due to the surface roughness corresponding to each processing accuracy is generated. In addition, in the case of the interference fit shown in FIG. 8 as well as the fit of the heating wire heater 2 with respect to the insertion hole 28 in the case of a clearance fit or an intermediate fit, the heat transfer with the heating wire heater 2 at the material structure level. A gap C is formed between the block 4 and the block 4.

  FIG. 9 is a diagram showing the relationship between the gap C in FIG. 8 and the internal temperature Ti of the heating wire heater 2. FIG. 9 shows, by experiment, the internal temperature Ti in the heat-resistant insulating material 14 in the metal pipe 10 when the gap C is changed under the condition that the target temperature Tt of the heat medium flowing through the flow path 6 set by the ECU 26 is constant. It is the result of observation. According to this figure, when the gap C becomes larger and the fit tends to fit, the heat resistance due to the air layer generated in the gap C is generated, and the heating wire heater 2 to the heat transfer block 4, and thus the flow path 6. Heat transfer to the heat medium flowing through is obstructed. As a result, although the heat generation amount of the heating wire heater 2 is constant because the target temperature Tt is constant, there is no escape of heat from the heating wire heater 2, and the inside of the heating wire heater 2 is insulated. As a result, the internal temperature Ti rises significantly.

  On the other hand, when the gap C is 0 mm, that is, when the fit is an intermediate fit where the fit tolerance is almost zero, the internal temperature Ti is lowered but not the lowest. Even if the gap C is −10 μm, the internal temperature is reduced. Ti is decreasing. This is because the gap C at the material structure level exists even in the case where the fit is an interference fit, but the clearance C is reduced and the thermal resistance is reduced due to a reduction in the air layer. This indicates that the heat transfer performance is enhanced as compared with the case of the second or intermediate fit, and the heat insulation state in the heating wire heater 2 is suppressed, and as a result, the internal temperature Ti is lowered.

  FIG. 10 is a diagram showing the temperature distribution in the heat transfer block 4 when the target temperature Tt of the heat medium flowing through the flow path 6 is 80 ° C. In this figure, a temperature sensor 44 is embedded in the heat transfer block 4 between the flow path 6 and the heating wire heater 2, and each temperature detected by the temperature sensors 24, 44 and the heat transfer block 4: Al, metal pipe, respectively. This is a result of estimating the temperature T of each part in the heat transfer block 4 based on the thermal conductivity of each part made of 10: SUS, heat-resistant insulating material 14: MgO.

  According to FIG. 10, when the fit of the heating wire heater 2 with respect to the insertion hole 28 is a clearance fit or an intermediate fit, as shown by the dotted line, the gap C is large, so that the insertion hole 28 and the metal pipe 10 are separated. It is estimated that a thermal gap of about 100 ° C. is generated between the outer surface 10 a of the metal pipe 10 and the inner surface 28 a of the insertion hole 28. As a result, the inside of the electric heater 2 becomes insulative, and the internal temperature Ti may reach about 500 ° C. while the target temperature Tt of the heat medium is 80 ° C.

  On the other hand, in this embodiment, since the fitting of the heating wire heater 2 to the insertion hole 28 is an interference fit, as shown by the solid line, the gap C is relatively small so that the gap between the insertion hole 28 and the metal pipe 10 is reduced. It is estimated that the thermal resistance is also reduced, and only a temperature gap Tg of about 10 ° C. is generated between the outer surface 10a of the metal pipe 10 and the inner surface 28a of the insertion hole 28. As a result, the heat insulation state in the electric heater 2 is also suppressed, and the internal temperature Ti is suppressed to about 250 ° C. while the target temperature Tt of the heat medium is 80 ° C.

  FIG. 11 is a diagram showing a time-series change in the temperature distribution of FIG. As is apparent from this figure, the temperature gap is initially Tg0, which is approximately 0 ° C., but the temperature gap gradually increases with time as Tg1 and Tg2, and the temperature of the heat medium becomes 80% of the target temperature Tt. When it reaches ° C., the temperature gap Tg stabilizes at about 10 ° C. which is the largest. That is, the temperature gap Tg is gradually increased from the start of the energization control by the ECU 26 and is held in the largest state when the target temperature Tt is reached.

  As described above, according to the vehicle heating apparatus 1 of the present embodiment, the heating wire heater 2 is fitted into the insertion hole 28 by shrink fitting, so that the heating wire heater 2 and the insertion hole 28 are in close contact with each other. The gap C at the material structure level between the metal pipe 10 of the heating wire heater 2 and the heat transfer block 4 can be reduced. Therefore, the thermal resistance due to the presence of the air layer between the heating wire heater 2 and the heat transfer block 4 can be reduced, and the temperature gap Tg generated between the heating wire heater 2 and the heat transfer block 4 can be reduced. Since it can be made small, the heat transfer efficiency of the heating apparatus 1 can be improved.

  Further, since the temperature gap Tg is large, it is possible to suppress the heat insulation state in the heating wire heater 2 resulting from the inhibition of the transmission from the heating wire heater 2 to the heat transfer block 4 and thus the heat medium flowing through the flow path 6. . Therefore, it is possible to prevent the heating wire heater 2 from being abnormally heated to be deteriorated by heat and to improve the durability of the heating wire heater 2 and thus the heating device 1.

  Further, since the heating wire heater 2 is fitted and fixed in the insertion hole 28 by an interference fit by reducing the gap C, an adhesive for fixing the heating wire heater 2 to the insertion hole 28 is unnecessary. In addition, it is not necessary to arrange a high thermal conductivity silicon material for improving the heat transfer efficiency in the gap C, or to embed a thermal conductive putty in the gap C. It is possible to prevent a decrease in heat transfer efficiency associated with.

The present invention is not limited to the above-described embodiments, and various modifications can be made.
For example, in the above embodiment, the heat transfer block 4 is formed of an aluminum alloy and the metal pipe 10 is formed of SUS. However, the heat transfer block 4 is not limited to these materials, and the heat transfer block 4 is a material having high heat shrinkage, The metal pipe 10 may be another material as long as it is a high heat resistant material.
Moreover, the insertion hole 28 of the said embodiment will not ask | require the processing method, if it can be formed with sufficient dimensional accuracy.

  Furthermore, the numerical values of the temperature and the fitting tolerance in the above embodiment are examples of experimental results, and are not limited to these numerical values. However, when the interference fit is at least 10 μm or more, the gap C at the material structure level between the heating wire heater 2 and the heat transfer block 4 is reduced, and the heat transfer efficiency and durability of the heating device 1 are effectively improved. It is preferable that it can be improved.

DESCRIPTION OF SYMBOLS 1 Heating device for vehicles 2 Heating wire heater 4 Heat-transfer block 6 Flow path 28 Insertion hole

Claims (2)

A heat transfer block having an insertion hole for accommodating a heating wire heater;
A flow path through which the heat medium heated by the heating wire heater flows,
The heating apparatus for vehicles, wherein the heating wire heater is fitted into the insertion hole by shrink fitting.   The heating apparatus for a vehicle according to claim 1, wherein the interference fit is 10 μm or more.

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