JPH11235918A - Heating heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost of the electric heating element part while securing a self- temperature control function by carrying an electric current by electrically serially connecting a heating element having a positive resistance temperature characteristic of suddenly increasing a resistance value at a prescribed preset temperature and heating resistance plates composed of a flexible metallic heating resistance material. SOLUTION: A heating element 90 and heating resistance plates 91, 92 composed of a flexible metallic heating resistance material are electrically connected in series to each other. The heating element 90 has a self temperature control function to self-control the heating temperature to a preset temperature since it is a PTC element having a positive resistance temperature characteristic of suddenly increasing a resistance value at a prescribed preset temperature when voltage of an on-vehicle power source is applied between terminals of the heating resistance plates from an external control circuit at heating time. Therefore, a calorific value is restrained since a value of an electric current flowing to a series circuit of the heating element 90 and the heating resistance plates 91, 92 suddenly reduces, so that a heating temperature of the heating element 90 and the heating resistance plates 91, 92 is self controlled to a preset temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating heat exchanger in which an electric heating element is integrated, and heats air using hot water (engine cooling water) heated by a vehicle engine (internal combustion engine) as a heat source. It is suitable for use in a vehicle heat exchanger.

[0002]

2. Description of the Related Art Conventionally, a heat exchanger in which an electric heating element of this kind is integrated has been proposed in Japanese Patent Application Laid-Open No. 5-69732. According to this conventional device, the electric heating element is integrated with a heating heat exchanger that heats air using hot water (engine cooling water) as a heat source. By energizing the body, the heat generated by the electric heating element can be radiated into the air to heat the air.

[0003] As the electric heating element, a PTC heater element made of a resistor material having a positive resistance-temperature characteristic whose resistance value rapidly increases at a predetermined set temperature T ₀ is used. The temperature self control function for self-regulating the heating temperature of the electric heating element to the set temperature T ₀ by the use of the PTC heater element can be exhibited.

[0004]

However, since the electric heating element is disposed in the core of the heat exchanger, it is formed in a flat shape similar to a flat tube through which hot water flows. Therefore, P
The TC heater element also needs to have a flat thin plate shape. Moreover, since the PTC heater element is made of a shock-resistant ceramic material such as barium titanate, damage such as cracking of the PTC heater element is likely to occur during the assembly process of the heat exchanger.

For this reason, it is conceivable to form the PTC heater element by dividing it into a number of pieces.
As the number of heater elements used increases, the cost of the electric heating element increases, the temperature of the gap between the PTC heater elements becomes lower than the temperature of the element, and the temperature variation of the air blown out from the heat exchanger increases. There is a defect. The present invention has been made in view of the above points, and in a heating heat exchanger that integrates an electric heating element, it is possible to reduce the cost of the electric heating element portion while ensuring the self-temperature control function of the PTC heater element. It is an object of the present invention to eliminate temperature variations in a heating element portion.

[0006]

In order to achieve the above object, according to the first to fifth aspects of the present invention, the electric heating element (9) incorporated in the heat exchange core (3) has a predetermined set temperature. Element (90) made of a resistor material having a positive resistance temperature characteristic whose resistance value increases rapidly and a heating resistor plate (91, 9) made of a flexible metal heating resistor material.
2), wherein the heat generating element (90) and the heat generating resistance plates (91, 92) are electrically connected in series to supply current.

According to this, since the heating element (90) has a positive resistance temperature characteristic in which the resistance value rapidly increases at a predetermined set temperature, the temperature of the heating element (90) reaches the set temperature. Then, the resistance value of the heating element (90) rapidly increases,
Heating element (90) and heating resistor plate (91, 92)
The amount of current flowing through the abruptly decreases, the calorific value is suppressed,
Heating element (90) and heating resistor plate (91, 92)
Can self-control the heat generation temperature to the set temperature.

In addition, the heating resistor plates (91, 92)
Is made of a flexible metal material such as dichromium, so that the heating element (90) and the heating resistance plates (91, 92) can be continuously formed over the entire length of the electric heating element (9) in the longitudinal direction. it can. Therefore, the air can be heated substantially uniformly by the combination of the heating element (90) and the heating resistor plates (91, 92) over the entire length of the electric heating element (9) in the longitudinal direction, so that the temperature variation of the air blown out of the heat exchanger can be reduced. Can be resolved.

Further, the heating element (90) is mainly responsible for the temperature control function, and the heating function can be mainly assigned to the heating resistor plates (91, 92). You only need to place one
On the other hand, the heat generating resistance plates (91, 92) can be made of a material much cheaper than the heat generating element (90). Therefore, the cost of the entire electric heating element (9) can be reduced.

Further, since the heat generating resistance plates (91, 92) are made of a flexible metal material such as dichromium, it is possible to greatly reduce the occurrence of crack damage and the like in an assembling process and the like.
And, specifically, the present invention, as described in claim 2,
Heating element (90) and heating resistor plate (91, 9)
2) are formed in a thin plate shape, and connection ends (91a, 92a) having a smaller thickness than other portions are formed at the ends of the heat generating resistance plates (91, 92). By bringing the (91a, 92a) into pressure contact with the heating element (90), it is possible to electrically connect the heating element (90) and the heating resistor plates (91, 92).

According to the present invention, specifically, a heating element (90) is disposed at a central portion in the longitudinal direction of the electric heating element (9), and the heating element (90) is provided. The heating resistor plates (91, 92) may be arranged on both left and right sides of the device. The present invention specifically relates to claim 4
As described, terminal portions (91b, 92b) for connection to an external circuit are provided at both left and right ends in the longitudinal direction of the electric heating element (9).
May be arranged.

According to the present invention, specifically, a heating element (90) is disposed at one end in the longitudinal direction of the electric heating element (9), and the electric heating element (9) is provided. The heat-generating resistor plate (9)
1, 92), and a heating resistor plate (91, 92)
Among them, a terminal portion (91b, 92b) for connection to an external circuit may be arranged at a portion on the other end side in the longitudinal direction of the electric heating element (9).

The reference numerals in parentheses of the above means indicate the correspondence with the concrete means described in the embodiments described later.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 3 show a first embodiment of a vehicle heating heat exchanger to which the present invention is applied. In FIG. 1, a heating heat exchanger H includes a hot water inlet side tank 1. And a hot water outlet side tank 2 and a heat exchange core 3 provided between the tanks 1 and 2.

The hot water inlet tank 1 is provided with an inlet pipe 4 through which hot water (engine cooling water) from a vehicle engine (not shown) flows in, and the hot water outlet tank 2 allows hot water to flow outside and return to the engine side. An outlet pipe 5 is provided. Since the heat exchanger of this example is symmetrical as shown in FIG. 1, the hot water inlet side tank 1 and the hot water outlet side tank 2 may be reversed left and right.

Each of the tanks 1 and 2 has a tank body 1
a and 2a, and a sheet metal 1b and 2b for closing the opening end surfaces of the tank main bodies 1a and 2a, and has a well-known tank structure in which the vertical direction in FIG. A large number of flat tube insertion holes (not shown) are formed in the sheet metal 1b, 2b in one or more rows in the vertical direction of FIG.

The heat exchanging core portion 3 includes a plurality of flat tubes 6 formed in a flat shape parallel to the flow direction of the air for heating (the direction of arrow A in FIGS. 1 and 2) in parallel in the vertical direction in FIG. Have been placed. A corrugated fin (fin means) 7 formed in a wave shape is arranged and joined between the plurality of flat tubes 6. This corrugated fin 7
As is well known, a large number of louvers (not shown) are cut and raised obliquely at a predetermined angle with respect to the flow direction A of the heating air, and the fin heat transfer coefficient is improved by forming the louvers. .

Openings at both ends of the flat tube 6 are inserted into tube insertion holes of the sheet metals 1b and 2b, respectively.
Joined. Further, side plates 8a and 8b are provided further outside the corrugated fins 7 on the outermost sides (upper and lower ends in FIG. 1) of the core portion 3, and these side plates 8a and 8b are disposed.
8b is joined to the outermost corrugated fin 7 and sheet metal 1b, 2b.

Further, instead of the flat tube 6, an electric heating element 9 is provided at a part of the heat exchange core 3. In the example of FIG. 1, electric heating elements 9 are installed at equal intervals at four locations (hatched portions) of the heat exchange core 3. In the heat exchange core portion 3, at the portion where the electric heating element 9 is installed, between the bent top portions of the adjacent corrugated fins 7, a holding plate 10 having a U-shaped cross section extending in the longitudinal direction of the flat tube 6. Has been arranged. As shown in FIG. 2, a closed end portion 10a of the holding plate 10 having a U-shaped bent shape.
Of the holding plate 10 is set so that the opening faces the air inlet side of the core section 3 for heat exchange and the opening 10b on the other end side faces the air outlet side of the core section 3 for heat exchange.

The holding plate 10 has a predetermined interval between the two opposing plate surfaces 10c and 10d, and in this state, the two plate surfaces 10c and 10d are respectively bent at the bent tops of the corrugated fins 7. To be joined. The electric heating element 9 is inserted into the holding plate 10 through the opening 10b and held. Here, the electric heating element 9 is electrically insulated and held with respect to the holding plate 10 by a structure described later.

The entire thickness of the holding plate 10 is
The thickness of the tube is set to be the same as
Corrugated fins with holding plate 10 in place of
7 can be installed between each other. By the way, the heat exchange in this example
In the heat exchanger, all of the above-mentioned components 1 to 8b are made of aluminum.
(Including aluminum alloy)
The holding plate 10 having a U-shaped cross section is also made of aluminum.
It is formed of aluminum.

The electric heating element 9 has the structure shown in FIGS. 2 and 3, and the horizontal direction (the longitudinal direction of the electric heating element) in FIG.
A heating element 90 having a circular thin plate shape is arranged at the center of the electric heating element 9. The heating element 90 is made of P made of a resistor material (for example, barium titanate) having a positive resistance temperature characteristic whose resistance value rapidly increases at a predetermined set temperature (for example, around 200 ° C.) T ₀ .
It is a TC heater element.

Heating resistance plates 91 and 92 are disposed on both the left and right sides of the heating element 90. The heating resistance plates 91 and 92 are made of a flexible metal heating resistance material, for example, dichromium (nickel-chromium alloy). As shown in FIG. 3 (a), it has a thin plate shape bent in a meandering shape. A necessary electric resistance value is secured by this meandering shape.

The portions of the heating resistor plates 91 and 92 that are electrically connected to the heating element 90 have connection ends 91a and 92a that are significantly thinner than the other portions. As shown in FIG. 3, the connection end 91a is connected to the heating element 9
The connection end 92 a is placed on the upper side of the upper surface of the heating element 90 so as to contact the lower side of the lower surface of the heating element 90. As a result, the heating element 90 is connected to the connection ends 91a and 92a.
Are sandwiched in a sandwich shape. The thickness of the heat generating resistance plates 91 and 92 is set to the connection ends 91a and 92.
By making the heating element 9 thicker than the heating element 90 by the thickness a, the thickness of the entire electric heating element 9 can be made uniform over its entire length in the left-right direction.

Further, the entire heating element 90 and the heating resistance plates 91 and 92 are formed by upper and lower insulating covering members 93,
The electric heating element 9 is covered with 94 so as to be held electrically insulated from the holding plate 10. As a specific material of the insulating covering members 93 and 94, an insulating film made of a resin having high heat resistance (for example, a polyimide resin) is preferable. In FIG. 3B, reference numeral 95 denotes a mating surface of the upper and lower insulating coating members 93 and 94.

With the above configuration, the heating element 90 and the heating resistor plates 91 and 92 are electrically connected in series, and both ends of the heating resistor plates 91 and 92 are taken out of the insulating covering members 93 and 94. , Terminal portions 91b, 9
2b. More specifically, the terminals 91b and 92b protrude downstream from the core 3 in the air flow direction A as shown in FIG. 1 and are electrically connected to an external control circuit (not shown). Then, power is supplied from the vehicle-mounted power supply to each electric heating element 9 via the external control circuit.

In FIG. 1, reference numerals 12 and 13 denote fasteners (bands) made of a metal material having excellent corrosion resistance such as stainless steel.
It is a member and is disposed on both the air inlet side surface and the air outlet side surface of the heat exchange core 3. Fastening member 12,
Reference numeral 13 has a hook portion having a bent shape at both ends thereof, and the hook portion is connected to the upper and lower side plates 8a, 8a.
locking grooves 8c, 8d formed at the center in the longitudinal direction of b
And attached between the upper and lower side plates 8a and 8b. By mounting the fastening members 12 and 13, a tightening force for pressing and holding the electric heating element 9 between the plate surfaces 10 c and 10 d of the holding plate 10 is applied to the heat exchange core 3.

Next, a method of manufacturing the above-described heating heat exchanger will be described. First, a core assembling step of assembling the heat exchanger configuration shown in FIG. 1 is performed. That is, the tubes 6 and the corrugated fins 7 of the heat exchange core 3 are alternately stacked, and the electric heating elements 9
At the position where the is installed (the four hatched portions in FIG. 1), a holding plate 10 having a U-shaped cross section extending in the longitudinal direction of the tube 6 is arranged between the bent top portions of the adjacent corrugated fins 7.

Here, in order to maintain the space between the two opposing plate surfaces 10c and 10d of the holding plate 10 at a predetermined distance, a dummy plate having a predetermined thickness of the plate is provided inside the holding plate 10. (Not shown). This dummy plate is formed of a material (for example, carbon or the like) having a heat resistance against an integral brazing process described later and having a property of not being brazed with aluminum. In this assembly process,
Tanks 1, 2, pipes 4, 5, and side plate 8
It goes without saying that a and 8b are also assembled.

Next, as described above, the assembled state of the assembled heat exchanger assembly is held by an appropriate jig (not shown), carried into a brazing furnace, and a brazing step is performed.
That is, the heat exchanger assembly is heated to a brazing temperature (about 600 ° C.) in a brazing furnace to melt the brazing material of the aluminum clad material of each member of the heat exchanger. Are brazed together.

After the brazing is completed, the heat exchanger assembly is taken out of the brazing furnace, and after the temperature of the heat exchanger assembly has dropped to room temperature, the heat exchanger core 3 of the heat exchanger assembly is cooled. Then, the dummy plates inserted inside the four holding plates 10 are taken out. Thereafter, the electric heating element 9 is inserted from the opening 10b toward the closed end 10a into a space at a predetermined interval formed inside the two opposing plate surfaces 10c and 10d of the holding plate 10.

That is, the electric heating element 9 is independently assembled separately from the heat exchanger assembly in the structure shown in FIG. 3, and the electric heating element 9 is inserted into the holding plate 10. At this time, the covering member 9 d is pressed against the holding plate 10,
The electric heating element 9 is assembled in the holding plate 10. After the electric heating element 9 is assembled, the hooks at both ends of the fastening members 12 and 13 are hooked on the locking grooves 8c and 8d of the upper and lower side plates 8a and 8b, and the upper and lower side plates 8a and 8
The fastening members 12 and 13 are mounted so that the heat exchange core 3 is compressed between the positions b.

Thus, a tightening force for pressing and holding the electric heating element 9 against the inside of the holding plate 10 is applied to the heat exchange core portion 3 to securely hold and fix the electric heating element 9 inside the holding plate 10. it can. At the same time, inside the electric heating element 9, the connection ends 91 of the heating resistance plates 91 and 92 are connected.
Since a pressing force acts on the sandwich-shaped sandwiching structure between the heat generating element 90a and the heat generating element 90, good electrical continuity can be established between them with a small contact resistance.

Next, the operation of the above configuration will be described.
When heating the passenger compartment, an air-conditioning blower fan (not shown) is operated to heat the air gap between the flat tube 6 and the corrugated fin 7 of the core portion 3 of the heat exchanger H for heating in the direction of arrow A. Air passes. On the other hand, warm water (heat source fluid) from the engine flows into the warm water inlet side tank 1 from the inlet pipe 4 by the operation of the water pump (not shown) of the vehicle engine.

The hot water is distributed to a number of flat tubes 6 in the inlet side tank 1 and radiates heat to the heating air via the corrugated fins 7 while flowing through the flat tubes 6 in parallel. The hot water that has passed through the many flat tubes 6 flows into the hot water outlet side tank 2 and is collected there, and the hot water flows out of the heat exchanger from the outlet pipe 5 and returns to the engine side.

On the other hand, when the temperature of the hot water from the engine is lower than the set temperature (for example, 80 ° C.) during heating, the terminal parts 91b and 91b of the heating resistance plates 91 and 92 of the electric heating element 9 are supplied from an external control circuit. The voltage of the vehicle-mounted power supply is applied between 92b. Thus, the heating element 90 and the heating resistance plates 91 and 92 are energized and generate heat. Heating element 9
The heat generated by the zero and the heat generating resistance plates 91 and 92 is transmitted to the corrugated fins 7 on both sides through the covering members 93 and 94 and the holding plate 10, and is radiated from the corrugated fins 7 to the heating air. Therefore, even when the temperature of the hot water is low, the heating air can be quickly heated to perform the immediate heating.

Here, the heating element 90 has a positive resistance-temperature characteristic having a resistance value that rapidly increases at a predetermined set temperature T ₀ .
Because it is TC elements, as is well known, has a self temperature control function for self-regulating the heating temperature to the set temperature T _0. That is, when the temperature of the heating element 90 reaches the set temperature (Curie point) T ₀ , the resistance value of the heating element 90 sharply increases.
The value of the current flowing through the series circuit of the heating elements 1 and 92 sharply decreases, the amount of heat generation is suppressed, and the heating temperature of the heating element 90 and the heating resistor plates 91 and 92 is set to a set temperature (Curie point) T
Can self-control to ₀ .

Furthermore, since the heat generating resistance plates 91 and 92 are made of a flexible metal material such as dichromium, the heat generating resistance plates 91 and 92 extend over the entire length of the electric heating element 9 in the longitudinal direction (left and right direction in FIG. 1).
The heating element 90 and the heating resistance plates 91 and 92 can be formed continuously. Therefore, the electric heating element 9 is combined with the heating element 90 and the heating resistance plates 91 and 92.
Since the air can be heated substantially uniformly over the entire length in the longitudinal direction, the temperature variation of the air blown out from the heat exchanger can be eliminated.

Furthermore, the heating element 90 composed of a PTC heater element mainly has a temperature control function, and the heating function can be mainly assigned to the heating resistance plates 91 and 92. The heating resistor plates 91 and 92 need only be provided with one PTC.
It can be made of a material much cheaper than the heater element, and cost reduction can be achieved. Further, since the heat generating resistance plates 91 and 92 can be made of a flexible metal material such as dichromium, the occurrence of crack damage and the like in the assembling process and the like can be greatly reduced.

(Second Embodiment) FIG. 4 shows a second embodiment. In the first embodiment, the terminals 91b and 92b of the heat generating resistance plates 91 and 92 are arranged at both ends in the longitudinal direction of the electric heating element 9. However, in the second embodiment, the heating element 90 composed of a PTC heater element is disposed at one end of the electric heating element 9 in the longitudinal direction, and from one end to the other end of the electric heating element 9 in the longitudinal direction. Heating resistance plates 91, 9
2 and the terminal portions 91b and 92b are both disposed at the other end of the electric heating element 9 in the longitudinal direction.
b and 92b are collected at the same site.

In the second embodiment, the heat generating resistance plates 91 and 92 are not formed in a meandering shape but formed in a straight line. (Other Embodiments) In the first and second embodiments, two heating resistor plates 91 and 92 are used, but one heating resistor plate may be used. In this case, the heating element 90 consisting of the PTC heater element is
One end of each of the heating resistor plates is electrically connected, the heating element 90 is provided with one of the positive and negative terminals, and the other end of the heating resistor plate is provided with the other of the positive and negative terminals. I just need.

In the first and second embodiments described above, the heat exchanger for vehicle heating has been described. However, the present invention is not limited to the vehicle heat exchanger, but is widely applied to various types of heating heat exchangers. Applicable. Further, the installation form of the electric heating element 9 is not limited to the form shown in FIG. 1, and it is needless to say that various changes can be made in response to changes in the specifications of the heating heat exchanger.

[Brief description of the drawings]

FIG. 1 is a perspective view of a heating heat exchanger according to a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view of an electric heating element installation portion of FIG.

FIG. 3A is a plan view of the electric heating element shown in FIGS.
The state which removed the upper insulating coating member is shown. (B) is BB sectional drawing of (a).

FIG. 4 is a plan view of an electric heating element according to a second embodiment of the present invention, showing a state where an upper insulating coating member is removed.

[Explanation of symbols]

1, 2 ... tank, 3 ... heat exchange core, 6 ... flat tube, 7 ... corrugated fin, 9 ... electric heating element, 90 ... heating element, 91, 92 ... heating resistance plate, 91a, 9
2a: Connection end, 91b, 92b: Terminal, 93, 94
... an insulating coating member, 10 ... a holding plate.

Claims (5)

[Claims] An electric heating element (9) is incorporated in a part of a heat exchange core (3) comprising a combination of a tube (6) through which a heat source fluid flows and a fin means (7). In the exchanger, as the electric heating element (9), a heating element (90) made of a resistor material having a positive resistance temperature characteristic whose resistance value rapidly increases at a predetermined set temperature, and a flexible metal heating resistance material A heating resistor plate (91, 92) comprising the heating element (90) and the heating resistor plate (9).
1, 92) are electrically connected in series to energize the heating heat exchanger. 2. The heat generating element (90) and the heat generating resistance plates (91, 92) are both formed in a thin plate shape. Connection ends (91a, 92a) having a reduced plate thickness
a) is formed, and this connection end (91a, 92a) is connected to the heating element (9).
0), the heating element (90)
The heat exchanger for heating according to claim 1, wherein an electric connection is made between the heating resistor plate (91, 92). 3. The heating element (90) is disposed at the longitudinal center of the electric heating element (9), and the heating resistance plates (91, 9) are provided on both left and right sides of the heating element (90).
The heat exchanger for heating according to claim 1 or 2, wherein 2) is arranged. 4. Terminal portions (91b, 92) for connection to an external circuit are provided at both left and right ends in the longitudinal direction of the electric heating element (9).
4. The heat exchanger for heating according to claim 3, wherein b) is arranged. 5. The heating element (90) is disposed at one end of the electric heating element (9) in the longitudinal direction, and from one end to the other end of the electric heating element (9) in the longitudinal direction. The heating resistor plates (91, 92) are disposed, and the electric heating element (9) is included in the heating resistor plates (91, 92).
The heat exchanger for heating according to claim 1 or 2, wherein terminal portions (91b, 92b) for connection to an external circuit are arranged at a portion on the other end side in the longitudinal direction of the heating device.