JPH1183371A - Laminated heat exchanger for cooling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve drainage of a laminated heat exchanger. SOLUTION: In a laminated heat exchanger for cooling, a depth H of a groove 94 recessed in a direction toward an inside of a flat tube 91 is set to 0.9±0.2 mm, and a louver ending position L corresponding to a contact part 94a of a side wall 94b with a fin 93 is set to 0 to 0.6 mm. Thus, since the condensate water can be drained by the groove 94 while ensuring a sufficient suction force for turning the condensed water toward the groove 94 by the louver 93c, drainage of the heat exchanger can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated heat exchanger for cooling (hereinafter abbreviated as a laminated heat exchanger) in which a flat tube is formed by a pair of plates formed in a bowl (bathtub) shape. This is effective when applied to an evaporator of a vehicle air conditioner.

[0002]

2. Description of the Related Art As is well known, an evaporator of a vehicle air conditioner cools air blown into a room by the heat of evaporation of a refrigerant. Therefore, a flat tube or a corrugated fin (hereinafter, fin) of the evaporator is used. Condensed water adheres and accumulates in the evaporator, increasing the ventilation resistance in the evaporator.
The problem that condensed water is blown toward the room easily occurs.

[0003] In response to this problem, the applicant has already disclosed
As described in JP-A-234377, an application has been made in which a flat tube is formed with a groove for draining condensed water.

[0004]

The inventors of the present invention have studied in detail the flow of condensed water adhering to flat tubes and fins in order to further improve the drainage of condensed water. The point became clear. That is, as shown in FIG. 9, the path of the condensed water flows toward the downstream side of the air flow with the valley 93b of the fin 93 as a gutter,
The first drainage path A is turned at the cutting portion 93c such as a louver toward the groove 94, and the fin 93 is turned at the cutting portion without turning.
The second valley 93b flows toward the downstream side of the air flow with the valley 93b as a gutter, and turns to the opposite valley at the end of the fin 93.
There is a drainage path B and a third drainage path C that goes to the groove on the downstream side of the air flow along the plate surface 91c of the flat tube 91.

[0005] In the first and third drainage paths A and C, the condensed water naturally (directly) flows into the groove 94 when going downstream, whereas in the second drainage path B, the condensed water flows into the end of the fin 93. When turning, the condensed water stays at the end of the fin 93 due to its surface tension. Also, when the condensed water flows toward the opposite valley, it may be blown off by the air flowing through the evaporator.

Accordingly, in order to further improve the drainage of the condensed water, it is necessary to turn the condensed water flowing through the second drainage path by a cutting part such as a louver and guide the condensed water to the groove, similarly to the first drainage path. There is. By the way, the force for turning the condensed water toward the groove at the cut portion is a suction force due to the capillary phenomenon (surface tension) in the groove. For this reason, if the groove depth of the groove is reduced, the suction force due to the capillary phenomenon can be increased, but the surface tension makes it difficult for the condensed water to flow through the groove. Therefore, it is necessary to select a groove depth at which the condensed water can flow in the groove while ensuring a sufficient suction force to turn the condensed water toward the groove at the cut portion.

[0007] In view of the above, it is an object of the present invention to improve the drainage performance of a laminated heat exchanger.

[0008]

The present invention uses the following technical means to achieve the above object. Claim 1
According to the invention described in Item 4, the groove depth (H) of the groove (94), which is depressed toward the inside of the flat tube (91), is:
0.9 ± 0.2 mm.

[0009] Thus, as is apparent from the test results described later, while ensuring a sufficient suction force to turn the condensed water toward the groove portion (94) at the cutting portion (93c), the condensed water is formed at the groove portion (94). Since the condensed water can be circulated, the drainage performance of the stacked heat exchanger can be improved. The groove depth (H) of the groove portion (94) is more preferably 0.9 ± 0.1 mm, as described in claim 2, in order to improve drainage.

In the invention according to claim 3, the cutting portion (93)
The end position (93d) of c) is a contact portion (94) between the side wall portion (94b) on the upstream side in the gas flow direction and the fin (93).
The position is the same as the position corresponding to a).
Thereby, a large suction force (force due to capillary action (surface tension) in the groove portion (94)) can be applied to the condensed water flowing to the cut portion (93c), so that more condensation Water can be diverted towards the groove (94). Therefore, the drainage performance can be further improved.

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

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In this embodiment, a laminated heat exchanger according to the present invention is applied to an evaporator 9 of a vehicle air conditioner. FIG. 1 is a schematic diagram of the vehicle air conditioner 1. is there. At the air upstream side of the air-conditioning casing 2, there are formed an inside air inlet 3 for sucking the air inside the vehicle and an outside air inlet 4 for sucking the outside air.
Is provided with an inlet switching door 5 for selectively opening and closing the suction port. The inlet switching door 5 is opened and closed by driving means such as a servomotor or by manual operation.

In the downstream portion of the inlet switching door 5,
A blower 7 according to the present embodiment is provided, and the air sucked from both suction ports 3 and 4 by this blower 7 is blown toward respective outlets 14, 15 and 17 described below. An evaporator 9 serving as an air cooling means is provided downstream of the blower 7 in the air, and all the air blown by the blower 7 passes through the evaporator 9. A heater core 10 serving as air heating means is provided downstream of the evaporator 9 in the air. The heater core 10 heats the air using the cooling water of the engine 11 as a heat source.

A bypass passage 12 for bypassing the heater core 10 is formed in the air-conditioning casing 2, and an air flow ratio between an air flow passing through the heater core 10 and an air flow passing through the bypass passage 12 is adjusted upstream of the heater core 10. An air mix door 13 is provided. The adjustment of the air volume ratio is adjusted by adjusting the opening of the air mix door 13.

At the most downstream side of the air-conditioning casing 2, there are provided a face outlet 14 for blowing out conditioned air to the upper body of the passenger in the passenger compartment, and a foot outlet 15 for blowing air to the feet of the passenger in the passenger compartment. Defroster outlet 1 for blowing air toward the inner surface of windshield 16
7 are formed. Each of the outlets 14, 1
Blow-out mode switching doors (blow-out adjusting means) 18, 19, and 20 are provided at the air upstream side of the air blowers 5 and 17, respectively. In addition, these blowing mode switching doors 18, 19,
20 is opened and closed by driving means such as a servomotor or by manual operation.

Next, the structure of the evaporator 9 will be described. FIG. 2 shows a cross section of the evaporator 9 cut in the direction of air flow. Reference numeral 91 denotes a plurality of plates formed by joining the outer peripheral portions of a pair of plates 91a and 91b formed in a bowl shape (bathtub). (Hereinafter, abbreviated as a tube), in which a refrigerant (cooling medium) such as Freon flows.

Incidentally, in the tube 91, there are wavy inner fins 92 for improving the heat transfer coefficient between the refrigerant and the tube 91 (plates 91a and 91b). In addition, between the tubes 91, the uneven surface 91c of the tube 91
Outer fins (hereinafter abbreviated as fins) 93 for promoting heat exchange between the air and the refrigerant flowing substantially parallel to the fins 93 are provided. It is formed in a wave (corrugated) shape so as to have a portion 93a.

The valleys (bends) 93b of the fins 93
Are joined by brazing in a state where they are in contact with each other at the uneven plane 91 c of the tube 91, and the fin 93 and the inner fin 9 are joined together.
2 and tubes 91 (plates 91a, 91b)
It is made of aluminum. In the present embodiment, both plates 91a and 91b are formed by pressing an aluminum material having a plate thickness of 0.4 to 0.6, while the fins 93 are formed by louvers (not shown) formed on the plane portion 93a. It is formed by a roller forming method together with the cutting portion 93c.

The louver 93c deflects air into the flat portion 93.
The heat transfer coefficient between the fins 93 and the air is improved by meandering both sides of a. Also, the louver 9 of the tube 91 (plates 91a and 91b) is used.
3c, a plurality of grooves 94 which are depressed toward the inside of the flat tube 91 and extend in a direction (gravity direction) orthogonal to the flat portion 93a are formed. In the present embodiment, the depth H is
It is about 0.9 mm.

Incidentally, as shown in FIG. 3, the groove depth H is defined by the distance between the fin 93 and the side wall 94b on the upstream side in the air flow direction in the groove 94 formed of the two side walls 94b and 94c and the bottom 94d. This is a dimension indicating a depression depth from the contact portion 94a to the bottom portion 94d. The cut end position 93d of the louver 93c is the same as the position corresponding to the contact portion 94a between the side wall portion 94b and the fin 93 (FIGS. 3 to 5).
reference). Here, the position where the cut end portion position 93d corresponds to the contact portion 94a and the same position do not mean exactly only the same position (L = 0), but, for example, a range of about L = 0 to +0.6 mm. That's what it says.

The direction of + means the direction toward the downstream of the air flow direction, and L is the cutting edge position 93d first encountered and the contact portion 94a when viewed from the contact portion 94a in the + direction.
The distance between a and a portion parallel to the ventilation direction. By the way,
Of the side wall portions 94b and 94c of the plurality of groove portions 94, the side wall portion 94c of the groove portion 94 on the most downstream side in the air flow direction is shown in FIG.
As shown in FIG. 5, the fins 93 are not in contact with each other, and a slight gap δ is formed (see FIGS. 3 to 5).

Next, features of the evaporator 9 according to the present embodiment will be described. FIG. 6 shows the relationship between the wind speed when the condensed water is blown off (hereinafter, this wind speed is referred to as a water jumping wind speed) and the groove depth H, using L (hereinafter, L is referred to as a louver break position L) as a parameter. This is a test result showing the relationship. As is clear from this test result, the water jumping wind speed becomes the largest when the groove depth H is 0.9 mm, and the water jumping wind speed increases as the louver break position L decreases. You can see that.

Therefore, the groove depth H is set to 0.9 mm,
Assuming that the louver break position L = 0, the condensed water is passed through the louver 93c.
The condensed water can be circulated in the groove portion 94 while securing a suction force sufficient to turn toward the groove portion 94, so that the drainage of the evaporator (stacked heat exchanger) 9 can be improved. . Note that the groove depth H is ideally preferably set to 0.9 mm as described above,
In consideration of variations such as manufacturing intersection, the groove depth H = 0.9
If ± 0.2 mm or H = 0.9 ± 0.1, practically sufficient drainage can be obtained.

Further, as described in the section of "Problems to be Solved by the Invention", the force for turning condensed water toward the groove 94 by the louver 93c is the suction force due to the capillary phenomenon (surface tension) in the groove 94. Therefore, the cut end position 9
It is desirable to make the 3d as close to the groove 94 as possible in order to improve drainage. Therefore, it is desirable to reduce not only the louver cut position L but also the dimension L _R (see FIG. 3) in the direction orthogonal to the louver cut position L.

The groove 94 at the most downstream side in the air flow direction
Since the gap δ is formed in the side wall portion 94c of the groove 94, it is possible to reliably prevent the condensed water from staying in the groove portion 94 in the groove portion 94. Therefore, the drainage of the evaporator 9 can be further improved. By the way, in the above-described embodiment, the cutting portion 93A that cuts a part of the flat portion 93a.
The louver 93c is formed as described above, but the present invention is not limited to this, and other types such as punching, slits, notches, etc. may be used (see FIGS. 7 and 8).

In the modified example shown in FIG.
A is formed in a valley (bent portion) 93 b of the end of the fin 93 on the air flow direction side. Thereby, drainage can be further improved. Further, in the above-described embodiment, the fin 93 has a simple wavy shape. However, the present invention is not limited to this, and may have another shape such as an offset fin as shown in FIG. .

In the above-described embodiment, as shown in FIG. 2, the grooves 94 are formed at three positions, that is, upstream, middle, and downstream with respect to the air flow direction. However, the present invention is not limited to this. Instead, the groove 94 may be formed at least on the downstream side. Further, in the present invention, the louver break position L is not limited to the above-mentioned size, and the drainage can be improved if the groove depth H is set to the above-mentioned predetermined size.

Further, in the above-described embodiment, the laminated heat exchanger for cooling according to the present invention is applied to the evaporator, but the laminated heat exchanger for cooling according to the present invention is not limited to this. Instead, the present invention can be applied to a laminated heat exchanger for cooling in which gas is cooled by another cooling medium such as water.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a vehicle air conditioner.

FIG. 2 is a cross-sectional view of the evaporator cut in the air flow direction.

FIG. 3 is an enlarged view of a downstream end portion in the air flow direction of FIG. 2;

FIG. 4 is an enlarged view of a downstream end portion in the air flow direction of FIG. 2;

FIG. 5 is a schematic diagram showing a groove depth H and a louver break position L. In the drawings, the louver also shows a cross-sectional shape.

FIG. 6 is a graph showing a relationship between a water splashing wind speed and a groove depth H using a louver break position L as a parameter.

FIG. 7 is a perspective view showing a modified example of a fin and a cutting section.

FIG. 8A is a perspective view of a fin, and FIGS.
(F) is a perspective view showing a modification of cutting part 93A.

FIG. 9 is a perspective view showing a drain path.

[Explanation of symbols]

91: flat tube, 92: inner fin, 93: outer fin, 94: groove.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Eiichi Torikoshi 1-1-1, Showa-cho, Kariya-shi, Aichi, Japan

Claims (4)

[Claims] 1. A pair of plates (91) formed in a bowl shape.
a, 91b) by joining the outer peripheral portions thereof,
A plurality of flat tubes (91) through which a cooling medium flows, and the flat tubes (9) interposed between the flat tubes (91).
1), the flat tube (9)
1) A wavy fin (93) for promoting heat exchange between the gas flowing outside and the cooling medium, and the fin (93) has a cut portion (93c) obtained by cutting a part thereof. Is formed, and the cutting portion (93c) of the flat tube (91) is formed.
A groove (94) that is depressed in a direction toward the inside of the flat tube (91) and extends in a direction intersecting with the gas flow direction is formed at a portion corresponding to the groove (94). ) Is 0.9 ± 0.9 ±
The heat exchanger according to claim 1, wherein the heat exchanger has a thickness of 0.2 mm. 2. A groove depth (H) of the groove (94) is:
A laminated heat exchanger for cooling, characterized by being 0.9 ± 0.1 mm. 3. The groove (94) has two side walls (9).
4b, 94c) and a bottom portion (94d). The position (93d) of the end of the cut portion (93c) is determined by the flow of the gas in the two side wall portions (94b, 94c). The heat exchanger according to claim 1, wherein the heat exchanger is located at the same position as a position corresponding to a contact portion (94 a) between the side wall portion (94 b) on the upstream side in the direction and the fin (93). vessel. 4. The louver according to claim 1, wherein the cut portion (93c) forms a louver for meandering the gas on both sides of the fin (93). Laminated heat exchanger for cooling.