JPH10288493A - Heat exchanger for heating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the electric characteristics of an electrical heating element from deteriorating and also to easily mount the electrical heating element to the core part of a heat exchanger for heating. SOLUTION: In a heat exchanger for heating in which an electrical heating element 9 is placed in the partial site of a core part for exchanging heat consisting of flat tubes 6 where hot water flows and a corrugated fin 7 being joined between the tubes 6, retention boards 10 and 11 being extended in the longitudinal direction of each tube is joined to a folded top part of the adjacent corrugated fin 7 with a specific spacing in the site where the electrical heating element 9 is placed in the core part for exchanging heat and the electrical heating element 9 is mounted between the two retaining boards 10 and 11, thus completing one-piece brazing of the core part for exchanging heat, mounting the electrical heating element 9 between the retaining boards 10 and 11, and hence preventing the electrical characteristics of the electrical heating element 9 from deteriorating due to the brazing of a core part 3 for exchanging heat.

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]

By the way, in the conventional apparatus described in the above publication, the electric heating element composed of the heating element and the electrode plate is brazed integrally with the core of the heating heat exchanger. Since the heating element is exposed to an atmosphere having a high brazing temperature (about 600 ° C. in the case of aluminum brazing), there is a problem that the electrical characteristics of the heating element are significantly impaired.

[0004] The present invention has been made in view of the above points,
There is no risk of damaging the electrical characteristics of the electric heating element, and
An object of the present invention is to make it possible to easily attach an electric heating element to a core of a heating heat exchanger.

[0005]

According to the first aspect of the present invention, there is provided a flat tube (6) through which a heat source fluid flows, and a corrugated fin joined between the flat tubes (6). (7) In the heating heat exchanger in which the electric heating element (9) is installed at a part of the heat exchange core part (3), the heat exchange core part (3) includes:
At the site where the electric heating element (9) is installed, holding plates (10, 11) extending in the longitudinal direction of the flat tube (6) are respectively provided on the bent tops of the adjacent corrugated fins (7).
Are bonded at predetermined intervals, and the two holding plates (10,
It is characterized in that the electric heating element (9) is electrically insulated and assembled during 11).

According to this, the holding plates (10, 11) are previously joined to the corrugated fin (7), and after the brazing of the heat exchange core (3) is completed, the two holding plates (1) are joined.
Since the electric heating element (9) can be assembled between 0 and 11), there is no possibility that the electrical characteristics of the electric heating element are impaired by brazing the heat exchange core (3). In addition, even if the corrugated fin (7) has a complicated shape having a corrugated shape, the two holding plates (10, 11) are joined to the corrugated fin (7) in advance, so that the corrugated fin (7) is The electric heating element (9) follows the flat shape of the two holding plates (10, 11) without crushing the wave shape.
Can be easily assembled. Therefore, both ease of assembling the electric heating element (9) and maintaining the shape of the corrugated fin (7) (securing heat transfer performance) can be favorably achieved.

Further, since the electric heating element (9) is electrically insulated and assembled between the two holding plates (10, 11), a heat exchange core ( The electric heating element (9) can be directly energized without causing an electric current to flow through the metal member (tube or the like) of 3). As a result, the metal member of the heat exchange core (3) can be prevented from being corroded by electrolytic corrosion, and the corrosion resistance of the heat exchanger can be secured.

According to the second aspect of the present invention, the flat tube (6), the corrugated fin (7) and the holding plate (1) are provided.
0, 11) is formed of aluminum and brazed integrally. Therefore, the holding plate (1)
0, 11) can be easily performed simultaneously with the integral brazing of the heat exchange core (3). In addition, even if the bent height of the corrugated fins (7) is slightly irregular, since the corrugated fins (7) and the holding plates (10, 11) are pre-brazed, the molten brazing material is not brazed at the time of brazing. The gap can be filled by penetrating into the gap between the bent top of the corrugated fin (7) and the holding plate (10, 11) by the capillary action. Therefore, corrugated fins (7)
Can be securely joined to the holding plates (10, 11), so that the heat generated by the electric heating element (9) can be reduced by the holding plates (1).
0, 11) can be efficiently transmitted to the corrugated fin (7).

According to the third aspect of the present invention, the electric heating element (9) has the positive electrode plate (9b) and the negative electrode plate (9c) interposed between the two electrode plates (9b, 9c). A heating element (9a) is provided, and the periphery of the two electrode plates (9b, 9c) is covered with a covering member (9d) made of an electrically insulating material, and the surface of the covering member (9d) is held. The electric heating element (9) is assembled between the two holding plates (10, 11) so as to be pressed against the plates (10, 11).

Accordingly, the electric insulation between the electric heating element (9) and the two holding plates (10, 11) can be surely insulated by the covering member (9d) and the covering member (9d).
The two electrode plates (9b, 9c) and the heating element (9
The protection of a) can be performed. According to a fourth aspect of the present invention, terminal portions (9e, 9f) for electrical connection with an external circuit are integrally formed on the positive electrode plate (9b) and the negative electrode plate (9c). And

Therefore, the electrical connection with the external circuit can be easily made by the terminal portions (9e, 9f) integrally formed on the two electrode plates (9b, 9c). In the invention according to claim 5, the terminal portions (9e, 9f) are connected to the positive electrode plate (9
b) and project from the negative electrode plate (9c) in the thickness direction of the heat exchange core (3).

According to this, the work of connecting the external circuit to the terminals (9e, 9f) can be easily performed without being hindered by the heat exchange core (3). In the invention according to claim 6, a tightening force is applied to the heat exchange core portion (3) so as to press and hold the electric heating element (9) between the two holding plates (10, 11). Fastening members (12, 1
3) is provided.

Accordingly, the electric heating element (9) can be securely held and fixed by the fastening members (12, 13).
The invention according to claim 7 relates to a method of manufacturing a heat exchanger for heating, in which flat tubes (6) and corrugated fins (7) of a heat exchange core (3) are alternately laminated. At the same time, in the portion of the heat exchange core portion (3) where the electric heating element (9) is installed, it extends in the longitudinal direction of the flat tube (6) between the bent tops of the adjacent corrugated fins (7). A core assembling step of arranging the two holding plates (10, 11) at predetermined intervals, and a flat tube (6) and a corrugated fin (7) of the heat exchange core (3) and the holding plate (10, 11); 11) and a heating element assembling step of assembling an electric heating element (9) between two holding plates (10, 11).

According to this, the electric heating element (9) can be easily assembled without deteriorating the electrical characteristics of the electric heating element. In addition, the code | symbol in the parenthesis of each said means shows the correspondence with the concrete means of embodiment mentioned later.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a heat exchanger for vehicle heating to which the present invention is applied, and FIG. 2 is a cutaway perspective view showing an enlarged main part of FIG. The heat exchanger has a hot water inlet side tank 1, a hot water outlet side tank 2, and a heat exchange core 3 provided between the two tanks 1, 2.

The hot water inlet side 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 side 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 faces of the tank main bodies 1a and 2a, and has a well-known tank structure in which the vertical direction in FIGS. A large number of flat tube insertion holes (not shown) are formed in the sheet metals 1b and 2b, and one or more rows are formed in the vertical direction in FIGS.

The heat exchanging core 3 is composed of a number 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 FIG. 1). Have been placed. Corrugated fins (fin members) 7 formed in a wave shape are 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 at a predetermined angle with respect to the flow direction of the heating air, and the louvers are formed to improve the fin heat transfer coefficient.

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 four positions of the heat exchange core 3 at equal intervals. Then, in the portion of the heat exchange core 3 where the electric heating element 9 is installed,
Flat metal holding plates 10 and 11 (see FIG. 2) extending in the longitudinal direction of the flat tube 6 are provided at predetermined intervals (L = thickness of the electric heating element 9) at the bent tops of the adjacent corrugated fins 7. They are arranged and joined, and the electric heating element 9 is assembled between the two holding plates 10 and 11.

By the way, in the heat exchanger of this embodiment, all of the above components 1 to 8b are formed of aluminum (including an aluminum alloy), and the flat holding plates 10 and 11 are similarly formed. It is formed of aluminum. The flat holding plates 10 and 11 have a thickness of 0.1
The width of the flat holding plates 10 and 11 (width in the heating air flow direction) is substantially the same as the width of the corrugated fins 7.
The lengths 0 and 11 in the longitudinal direction (left and right dimensions in FIG. 1) are substantially the same as the dimensions between the sheet metals 1b and 2b.

The electric heating element 9 has a structure shown in FIG. 3 and includes a plate-shaped heating element 9a and elongated flat plate-shaped electrode plates 9b and 9c arranged on both front and back surfaces of the heating element 9a. It has a three-layer sandwich structure. The entire periphery of the electrode plates 9b and 9c is covered with a covering member 9d made of an electrically insulating material.
Here, the heating element 9a is set at a predetermined set temperature (for example, 9
(Around 0 ° C.) A PTC heater element made of a resistor material (eg, barium titanate) having a positive resistance temperature characteristic whose resistance value rapidly increases at T ₀ , and has a plate thickness of 1.0 to
It is about 2.0 mm.

The two electrode plates 9b and 9c of the heating element 9a are formed of a conductive metal material such as aluminum, copper, and stainless steel, and have a thickness of about 0.1 to 0.5 mm. The lengths of these two electrode plates 9b and 9c in the longitudinal direction (the sizes in the left and right directions in FIG. 1) are substantially the same as those of the holding plates 10 and 11.
A plurality of heating elements 9a (four in the example of FIG. 3) are arranged in the longitudinal direction of both electrode plates 9b and 9c. The heat generating element 9a and the two electrode plates 9b and 9c are brought into pressure contact with each other to obtain electrical continuity between them.

The electric heating element 9 is configured such that the covering member 9 d is pressed against the holding plates 10 and 11, so that the electric heating element 9 has two holding plates 10 and 11.
Assembled between. Here, the covering member 9d performs an electrical insulating action between the holding plates 10, 11 and the two electrode plates 9b, 9c, and conducts heat of the heating element 9a to the holding plates 10, 11. To play a role, holding plate 1
The thickness t1 of the covering member 9d between the electrodes 0 and 11 and the two electrode plates 9b and 9c is formed into a thin film having a thickness of about 25 to 100 .mu. To secure a good heat conducting action.

On the other hand, the thickness t2 of the covering member 9d on the side of the heating element 9a is increased to about 1 to 2 mm to protect the heating element 9a. Covering member 9d
As a specific material, a highly heat-resistant resin (for example, a polyimide resin or the like) is preferable. The electrode plate 9b is a positive electrode plate, and the electrode plate 9c is a negative electrode plate, and terminals 9e and 9 for electrical connection to an external circuit are provided, respectively.
f is integrally formed. In this example, the two terminal portions 9e and 9f protrude forward (in the direction opposite to the air flow direction A) of the heat exchange core portion 3. The terminal 9e of the positive electrode plate 9b is formed at the right end of the positive electrode plate 9b as shown in FIG. 1, and the terminal 9f of the negative electrode plate 9c is formed at the left end of the negative electrode plate 9c. Is formed. Both terminals 9
The projecting directions of e and 9f may be on the rear side (air flow direction A) of the heat exchange core portion 3, that is, it may be in the thickness direction of the heat exchange core portion 3.

The electrode plates 9b, 9c of each electric heating element 9
An external control circuit (not shown) is electrically connected to the terminal portions 9e and 9f integrally formed with the power supply unit, and power is supplied to each electric heating element 9 from a vehicle-mounted power supply via the external control circuit. Reference numerals 12 and 13 denote fastening members made of a metal material having excellent corrosion resistance such as stainless steel.
Are arranged on both the air inlet side surface and the air outlet side surface. Each of the fastening members 12 and 13 has a hook portion formed in a bent shape at both ends thereof, and this hook portion is provided with locking grooves 8c and 8d formed at the longitudinal center portions of the upper and lower side plates 8a and 8b. And attached between the upper and lower side plates 8a and 8b. The fastening members 12, 13
By mounting the electric heating element 9, the two holding plates 10, 11
Between the heat exchange core portion 3 and the clamping force to be pressed and held during the heat exchange.

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
In the part where the is installed (the four hatched portions in FIG. 1), two holding plates 10 and 11 extending in the longitudinal direction of the tube 6 are spaced apart from each other by a predetermined interval between the bent tops of the adjacent corrugated fins 7. Deploy. In order to maintain a predetermined interval between the two holding plates 10, 11, the two holding plates 10, 1
1, a dummy plate (not shown) having this predetermined thickness is inserted.

This dummy plate is formed of a material (for example, carbon or the like) having a heat resistance to an integral brazing step described later and a property not to be aluminum brazed. In this assembly process, tanks 1, 2, pipes 4,
Of course, 5 and the side plates 8a 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, and the brazing material of the clad material of each member of the heat exchanger is melted. The members are brazed together.

After the brazing is completed, the heat exchanger assembly is carried out of the brazing furnace, and after the temperature of the heat exchanger assembly has dropped to room temperature, the electric heating element 9 is assembled. In other words, the electric heating element 9 alone has a three-layer sandwich structure in which the front and back surfaces of the plate-shaped heating element 9a are sandwiched between the plate-shaped electrode plates 9b and 9c separately from the heat exchanger assembly. The entire periphery of the electrode plates 9b and 9c is covered with a covering member 9d.

Then, the dummy plate inserted between the four holding plates 10 and 11 in the heat exchange core 3 of the heat exchanger assembly is taken out, and the two holding plates 10 and 1 are taken out.
1 in such a manner that the covering member 9 d is pressed against the holding plates 10 and 11 in a space formed at a predetermined interval between the electric heating elements 9.
Is assembled between the two holding plates 10 and 11. After this assembling, the hook portions at both ends of the fastening members 12, 13 are hooked on the locking grooves 8c, 8d of the upper and lower side plates 8a, 8b, so that the fastening members 12 are located between the upper and lower side plates 8a, 8b. , 13 are mounted such that the heat exchange core 3 is compressed.

Thus, a tightening force for pressing and holding the electric heating element (9) between the two holding plates (10, 11) is applied to the heat exchange core (3), and the electric heating element (9) is pressed. Is securely held and fixed between the two holding plates 10 and 11. Next, the operation of the above configuration will be described. When heating the passenger compartment, an air-conditioning blower (not shown) is operated, and the air for heating is provided in the space between the flat tube 6 and the corrugated fin 7 of the core portion 3 of the heating heat exchanger as shown by an arrow A. 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 external control circuit supplies the terminal portions 9 of the two electrode plates 9b and 9c.
Apply a voltage from the vehicle power supply between e and 9f. This allows
The heating element 9a is energized to generate heat. Heat generated by the heating element 9a is generated by the electrode plates 9b and 9c, the covering member 9d, the holding plate 10,
Through 11, it is conducted to the corrugated fins 7 on both sides,
Heat 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.

The heating element 9a of the electric heating element 9 is a PTC element having a positive resistance temperature characteristic whose resistance value increases rapidly at a predetermined set temperature T ₀ . A self-temperature control function for self-control to the temperature T ₀ is provided. By the way, the holding plates 10 and 11 are previously attached to the corrugated fin 7 having a complex shape having a corrugated shape.
And the electric heating element 9 is assembled along the flat shape of the holding plates 10 and 11, so that the corrugated fins 7 do not collapse when the electric heating element 9 is assembled. Therefore, even if the electric heating element 9 is arranged between the corrugated fins 7, the corrugated fins 7 can be maintained in a corrugated shape and the heat transfer performance can be secured.

When the electric heating element 9 is directly joined to the corrugated fin 7, if the bent height of the corrugated fin 7 is not uniform, as shown in FIG. A gap is formed between the bent top of the fin 7 and the electric heating element 9, and the heat of the electric heating element 9 may not be efficiently transmitted to the corrugated fin 7. In contrast, according to the present embodiment, since the corrugated fins 7 and the holding plates 10 and 11 are brazed in advance, even if the corrugated fins 7 have some irregularities in the bending height, they are melted during brazing. The brazing material is bent by capillarity to the bent top of the corrugated fin 7 and the holding plates 10 and 1.
1, and can fill this gap. Therefore, each bent top of the corrugated fin 7 can be securely joined to the holding plates 10 and 11, and the heat generated by the electric heating element 9 can be efficiently transmitted from the holding plates 10 and 11 to the corrugated fin 7.

(Other Embodiments) In the above embodiments, the heat exchanger for heating a vehicle has been described. However, the present invention is not limited to a heat exchanger for a vehicle, but may be applied to a heat exchanger for heating for various purposes. Widely 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.

Further, the electric heating element 9 is made of an adhesive resin as a covering member 9 d of the electric heating element 9, and the electric heating element 9 is attached to the holding plate 10.
11 can also be adhesively fixed. In this case, the fastening members 12 and 13 can be eliminated.

[Brief description of the drawings]

FIG. 1 is a perspective view of a heating heat exchanger to which the present invention is applied.

FIG. 2 is an enlarged perspective view of an electric heating element installation section showing one embodiment of the present invention.

3A is a partially cutaway perspective view of an electric heating element according to an embodiment of the present invention, FIG. 3B is a cross-sectional view of the electric heating element,
(C) is a longitudinal sectional view of the electric heating element, and (d) is a plan view of the electric heating element.

FIG. 4 is an enlarged view of an electric heating element installation portion showing a comparative example of the present invention.

[Explanation of symbols]

1, 2, tank, 3 heat exchange core, 6 flat tube, 7 corrugated fin, 9 electric heating element, 9a heating element, 9b, 9c electrode plate, 9d coating member, 9
e, 9f terminal part, 10, 11 holding plate, 12, 13 ...
Fastening members.

Claims (7)

[Claims] 1. A flat tube through which a heat source fluid flows.
Are arranged in parallel, and a corrugated fin (7) is joined between the many flat tubes (6) to form a heat exchange core (3). In a heating heat exchanger in which an electric heating element (9) is installed in a part of (3), a part of the heat exchanging core (3) where the electric heating element (9) is installed is: The holding plates (10, 11) extending in the longitudinal direction of the flat tube (6) are respectively joined to the bent tops of the adjacent corrugated fins (7) at predetermined intervals, and the two holding plates (10, A heating heat exchanger wherein the electric heating element (9) is electrically insulated and assembled during 11). 2. The heating system according to claim 1, wherein the flat tubes, the corrugated fins, and the holding plates are made of aluminum and are integrally brazed. For heat exchanger. 3. The electric heating element (9) includes a positive electrode plate (9b) and a negative electrode plate (9c), and a heating element (9b) arranged between the two electrode plates (9b, 9c). 9a), and the periphery of the two electrode plates (9b, 9c) is covered with a covering member (9d) made of an electrically insulating material. The surface of the covering member (9d) is covered with the holding plate (10, 1).
Heat exchange for heating according to claim 1 or 2, wherein the electric heating element (9) is assembled between the two holding plates (10, 11) so as to be pressed against 1). vessel. 4. A terminal part (9e, 9f) for electrical connection to an external circuit is integrally formed on each of the positive electrode plate (9b) and the negative electrode plate (9c). The heat exchanger for heating according to claim 3 which does. 5. The terminal portions (9e, 9f) protrude from the positive electrode plate (9b) and the negative electrode plate (9c) in the thickness direction of the heat exchange core (3). The heat exchanger for heating according to claim 4, characterized in that: 6. A fastening member for applying a tightening force to the heat exchange core (3) so as to press-hold the electric heating element (9) between the two holding plates (10, 11). (1
The heat exchanger for heating according to any one of claims 1 to 5, further comprising (2, 13). 7. A flat tube through which a heat source fluid flows.
Are arranged in parallel, and a corrugated fin (7) is joined between the many flat tubes (6) to form a heat exchange core (3). (3) A method for manufacturing a heat exchanger for heating, in which an electric heating element (9) is installed at a part of a part, wherein the flat tube (6) and the corrugated fin (7) of the heat exchange core (3) are provided. ) Are alternately stacked, and at the portion of the heat exchange core (3) where the electric heating element (9) is installed, the flattening is performed between the bent tops of the adjacent corrugated fins (7). A core assembling step of arranging two holding plates (10, 11) extending in the longitudinal direction of the tube (6) at a predetermined interval; and a flat tube (6) and a corrugate of the heat exchange core (3). Fin (7) and the holding plate (10, 1) a heating step of integrally brazing; and a heating element assembling step of assembling the electric heating element (9) between the two holding plates (10, 11). Manufacturing method of heat exchanger for industrial use.