JP2000146477A - Laminated heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thinner laminate heat exchanger capable of improving heat exchange efficiency by eliminating stagnation on the side of the upstream of beads while securing durability. SOLUTION: A plurality of beads 25 are formed on a pair of plates of a liquid tube element, each of which bead is protruded into refrigerant flow passages correspondingly to each of the plates and is joined with each other. The plurality of the beads 25 are disposed such that bead positions of a line of the adjacent beads arranged perpendicularly to a refrigerant flow passage direction correspondingly to a position of the bead line between the beads. There is satisfied a relationship C<D, C<A, 1<B/A<1.3 among A, B, C, D where A denotes a pitch perpendicular to the refrigerant flow passage direction of the beads 25, B a pitch of the beads 25 in the direction of the refrigerant flow passage, C a width of a skirt of the bead 25 in the direction perpendicular to the refrigerant flow passage direction, D a width of the skirt of the bead 25 in the direction of the refrigerant flow passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a laminated heat exchanger such as a laminated evaporator used for an automobile or an air conditioner for an automobile.

[0002]

2. Description of the Related Art Generally, a laminated heat exchanger used in an automobile or an air conditioner for an automobile includes a radiator,
There are evaporators, condensers, heater cores and the like.

[0003] Among them, for example, a laminated evaporator constituting a refrigerating cycle of an air conditioner for an automobile is provided in a cooler unit in a vehicle cabin, and a low-pressure mist-like refrigerant is introduced into the inside by an expansion valve. Thus, heat exchange with intake air is performed.

[0004] The core portion through which the intake air of this type of laminated evaporator passes, a flat liquid pipe element in which a pair of plates are combined in the middle and a refrigerant flow passage is formed inside, and heat transfer fins are formed. It is configured so as to be stacked in large numbers through the intermediary. A large number of beads projecting into the coolant channel are formed on the plate of the liquid tube element. Therefore, the refrigerant flowing in the liquid pipe element is agitated by these many beads, and the flow is diffused. Thereby, the heat exchange efficiency of the evaporator is improved.

[0005]

In recent years, there has been an increasing demand for thinner and higher-performance heat exchangers from the viewpoint of making air conditioners for automobiles more compact.

However, if the thickness of the heat exchanger in the air passage direction is simply reduced, the interval between the beads in the direction perpendicular to the refrigerant flow direction is reduced, and the flow velocity of the refrigerant in the liquid pipe element increases. . For this reason, as shown in FIG.
On the upstream side of the bead 25 in the refrigerant flow direction, there is a problem that a refrigerant stagnation region 24 that hardly flows and does not contribute to heat exchange is generated, thereby deteriorating the performance as a heat exchanger. Further, since the bead also has a function of improving the durability strength as a heat exchanger, it is necessary to take care not to reduce the strength when forming the bead.

On the other hand, Japanese Patent Application Laid-Open No. Hei 7-167581 discloses a method for setting a desired heat exchange efficiency, passage resistance, and strength by setting ranges of a bead width, a pitch, a liquid tube element thickness, a plate thickness, and the like. And the like are disclosed. However,
In this laminated heat exchanger, the width and pitch of the bead are the shortest dimensions in a plane, and the relationship with the flow direction of the refrigerant is not studied. Therefore, it is considered insufficient from the viewpoint of making the heat exchanger as thin as possible and reliably avoiding the generation of the stagnation region 24 of the refrigerant as shown in FIG. Further, the strength of the heat exchanger is studied only with respect to the plate thickness, and no consideration is given to the point that a change in the width or pitch of the bead affects the strength as a whole. Therefore, it can be said that it is difficult to solve the above-mentioned problem with this type of conventional stacked heat exchanger.

The present invention has been made in view of such problems of the prior art, and an object of the present invention is to eliminate heat stagnation on the upstream side of a bead while ensuring durability, thereby improving heat exchange efficiency. An object of the present invention is to provide a thin stacked heat exchanger which can be improved.

[0009]

According to the first aspect of the present invention, there is provided a liquid tube element having a pair of plates combined in a middle state and having a flow passage formed therein. A laminated heat exchanger having a core portion formed by laminating a plurality of fins via fins, wherein the pair of plates correspond to a plurality of beads projecting into the flow path and being joined to each other. The plurality of beads are arranged such that the bead positions of the bead rows arranged in a direction perpendicular to the flow path direction correspond to the positions between the beads of the adjacent bead rows, and the flow direction of the beads The pitch A in the direction perpendicular to the pitch, the pitch B in the flow direction of the bead, the width C in the direction perpendicular to the flow direction of the hem of the bead, and the width D of the flow direction of the hem of the bead are C <D, C <A, 1 <B / A <
1.3.

Further, according to a second aspect of the present invention, in the laminated heat exchanger according to the first aspect, the pitch A,
The pitch B, the width C, and the width D are 3.4 mm ≦ A ≦ 3.
95mm, 4.0mm ≦ B ≦ 4.5mm, 3.0mm ≦
It is characterized by further satisfying the relationship of C ≦ 3.9 mm, 3.0 mm ≦ D ≦ 3.9 mm.

According to a third aspect of the present invention, there is provided the laminated heat exchanger according to the second aspect, wherein a width E of the top of the bead in a direction perpendicular to a flow path direction and a flow of the top of the bead are changed. The width F in the road direction is E ≦ F, 1.0 mm ≦ E ≦ 1.8 m
m, 1.0 mm ≦ F ≦ 1.8 mm.

According to a fourth aspect of the present invention, in the laminated heat exchanger according to the second aspect, the thickness G of the core portion in a direction in which air passes is 45 mm ≦ G ≦ 60 m.
m, is satisfied.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a laminated evaporator according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a liquid tube element and a heat transfer fin, and FIG. 3 is a sectional view of the laminated evaporator.

As shown in FIG. 1, a laminated evaporator 100 of the present embodiment has a core portion 10 which is a heat exchanger body.
And a tank 1 which exchanges heat between refrigerant flowing from the refrigerant inlet hole 14 and flowing out of the refrigerant outlet hole 15 through the core portion 10 and air flowing in a direction perpendicular to the plane of FIG. It is intended to be.

The core part 1 of the laminated evaporator 100
No. 0 is constituted by laminating a plurality of liquid pipe elements 2 each having a pair of plates P1 and P2 facing each other with concave surfaces facing each other in the middle, via heat transfer fins 3 (FIG. 2). reference). Note that, in FIG.
The liquid tube element 2 and the heat transfer fins 3 are only partially illustrated and the others are omitted.

As shown in FIGS. 2 and 3, a partition wall 23 is formed at the center of each of the plates P1 and P2.
Therefore, a U-shaped refrigerant flow path 22 is formed inside each liquid pipe element 2, and the refrigerant flowing from one lower end portion 21 has a U-shaped refrigerant flow, for example, in a direction indicated by an arrow in FIG. 3. It flows out from the other lower end portion 21 through the refrigerant flow path 22.

2 is provided below the evaporator 100.
The tank 1 has a top plate 11 and a bottom plate 1 each having a gutter shape.
2 and the tank 1
Is a plurality of slit-like connection holes 13 formed in the top plate 11.
The lower end portions 21 of the liquid pipe elements 2 are respectively inserted into the liquid pipe elements 2 and brazed in a liquid-tight manner so as to be joined to the liquid pipe elements 2.

A coolant inlet hole 14 and a coolant outlet hole 15 are formed on the lower surface of the bottom plate 12 of one of the tanks 1, and a partition plate is provided between the coolant inlet hole 14 and the coolant outlet hole 15. 6 is provided so that the refrigerant does not flow. The refrigerant formed into a mist of low pressure by the expansion valve 4 flows into the refrigerant inlet hole 14, and the refrigerant after the heat exchange flows out from the refrigerant outlet hole 15 and returns to the compressor.

In the laminated evaporator 100, the flange 5 is brazed to the refrigerant inlet hole 14 and the refrigerant outlet hole 15 described above, and the expansion valve 4 is attached to the flange 5. The expansion valve 4 is a so-called integral type expansion valve in which an expansion valve is built in a block in which a refrigerant outflow / inflow hole is formed. A female screw hole 51 is formed in the flange 5, and the expansion valve 4 can be fixed to the flange 5 by inserting a bolt 7 into a through hole 41 formed in the expansion valve 4 and tightening the bolt 7. Has become.

FIG. 4 is a perspective view schematically showing the flow of the refrigerant in the laminated evaporator. As described above, the refrigerant flowing into the refrigerant inlet hole 14 is supplied from the first region 31 of the tank 1 provided with the refrigerant inlet hole 14 to each of the liquid pipe elements 2.
Flows through the U-shaped refrigerant flow path 22 through the lower end 21 of the tank 1 and flows from the other lower end 21 to the second region 32 of the other tank 1. Since the other tank 1 is not provided with the partition plate 6, the refrigerant flowing into the tank 1 flows to the third region 33 of the tank 1 and the liquid pipe element 2 After flowing from the lower end portion 21 through the U-shaped refrigerant flow path 22 to the fourth region 34 of the tank 1 in which the refrigerant outlet hole 15 is formed from the other lower end portion 21, it flows out from the refrigerant outlet hole 15. Return to the compressor. In addition,
Various types have been known for the flow of the refrigerant in the core portion 10 and the positions of the refrigerant inlet holes 14 and the refrigerant outlet holes 15 and can be changed.

FIG. 5A is a view of a bead formed on a plate as viewed from the top, and FIG. 5B is a view of FIG.
FIG. 5A is a cross-sectional view taken along the line XX, and FIG.
It is sectional drawing which follows the YY line of (A).

As shown in FIG. 3, a pair of plates P
Each of P1 and P2 has a plurality of beads 25 protruding into the coolant channel 22. The plurality of beads 25 are formed so that their positions correspond between the pair of plates P1 and P2, and the tops 26 of the beads 25 are joined by brazing.

The plurality of beads 25 are arranged so that the bead positions of the bead row R1 arranged in the direction perpendicular to the flow path direction correspond to the positions between the beads of the adjacent bead rows R2 and R3. ) It has a lattice shape.

The pitch A of the bead 25 in the direction perpendicular to the direction of the refrigerant flow path 22, the pitch B of the bead 25 in the direction of the refrigerant flow path 22, and the width of the foot of the bead 25 in the direction perpendicular to the direction of the refrigerant flow path 22. C, the width D of the bottom of the bead 25 in the direction of the refrigerant flow path 22 is represented by the following relationship: C <D (1) C <A (1) C <A (1) 1 <B / A <1.3 (3) Is set to meet.

According to the equation (1), the shape of the bead 25 is an infinite circle or an elliptical shape whose major axis is along the direction of the refrigerant flow path 22, that is, the flow direction of the refrigerant. Also, from equation (2),
The gap H between the beads when viewed from the flow direction of the refrigerant (FIG. 5A)
Cf.). The lower limit of the formula (3) is determined from the viewpoint of securing a predetermined flow resistance, and the upper limit is determined from the viewpoint of securing a predetermined durability.
1.1 <B / A <1.2, more preferably B / A =
1.15 is set.

The above-mentioned pitch A, pitch B, width C and width D satisfy the following equations (4) to (7) in addition to the above equations (1) to (3). The setting is desirable from the viewpoint of maintaining the durability and improving the heat exchange performance while reducing the thickness (width) of the stacked evaporator in the air passage direction. In other words, the bead of the heat exchanger has been conventionally formed by roll forming or press forming a flat plate, but if this bead is formed too small, the root of the bead with large plastic deformation becomes thin. Too much, resulting in poor durability. On the other hand, if the bead is formed too large, the number of beads in the limited space occupied by the heat exchanger (the width of the heat exchanger) decreases,
It becomes a product with inferior performance. Thus, according to experimental studies by the present inventors, it has been found that a heat exchanger having the following numerical range is a heat exchanger that maintains durability and has a good heat exchange rate.

3.4 mm ≦ A ≦ 3.95 mm (4) 4.0 mm ≦ B ≦ 4.5 mm (5) 3.0 mm ≦ C ≦ 3.9 mm (6) 3.0 mm ≦ D ≦ 3.9 mm (7) Further, the width E of the top 26 of the bead 25 in the direction perpendicular to the direction of the coolant flow path 22 and the width F of the top of the bead 25 in the direction of the coolant flow path 22 are as follows: E ≦ F (8) 1.0 mm ≦ E ≦ 1.8 mm (9) 1.0 mm ≦ F ≦ 1.8 mm (10)

According to equation (8), the shape of the top 26 of the bead 25 is a circular or elliptical shape in which the major axis extends along the refrigerant flow path 22, that is, the flow direction of the refrigerant, or a circular shape. Thus, the flow of the refrigerant near the top 26 of the bead 25 becomes smooth. Further, according to the expressions (9) and (10), it is possible to secure a predetermined joining area in the bead 25 between the pair of plates P1 and P2 while maintaining the good formability of the bead 25, and improve the durability strength. Can be planned.

Further, in the present embodiment, the thickness G of the core portion 10 of the laminated evaporator 100 in the air passage direction can be reduced as described above, and the thickness G of the core portion 10 is 45 mm ≦ G ≦ 60 mm (11)

Therefore, the laminated evaporator 10
0 can be made compact, the degree of freedom of the layout of the air conditioner can be increased, and the space occupying the vehicle interior space can be reduced.

Next, the operation of the present embodiment will be described.

The refrigerant made into a low-pressure mist by the expansion valve 4 flows into the first region 31 of the tank 1 from the refrigerant inlet hole 14. As shown in FIG. 3, the refrigerant flows through the U-shaped refrigerant flow path 22 through the lower end 21 of each liquid pipe element 2.

FIGS. 6A and 6B are diagrams schematically showing the measurement results of the flow state between the beads. FIG. 6A is a diagram showing the case of the laminated evaporator of the present embodiment, and FIG. FIG. 7 is a diagram showing a measurement result of a surface temperature distribution of a plate, in which FIG. 7A is a diagram showing a case of a laminated evaporator of the present embodiment, and FIG. 7B is a diagram showing a conventional laminated evaporator. It is a figure which shows the case of a type evaporator.

The refrigerant is a bead 25 having an oval or oval shape.
Smoothly sent along the surface. In addition, since the gap H is formed between the beads as viewed from the flow direction of the refrigerant (see FIG. 5A), the refrigerant flows between the adjacent beads 25 without being narrowed so much. In other words, there is no portion where the flow velocity increases due to the restriction of the flow, and the degree of freedom is given to the flow of the refrigerant, and an appropriate vortex 27 is formed as shown in FIG. As a result, as shown in FIG. 7 (A), the stagnation of the refrigerant, which tends to occur conventionally on the upstream side of the bead 25, is eliminated. Therefore, the refrigerant always circulates around the refrigerant flow path 22 and has no stagnant portion, so that the heat exchange area per liquid tube element is increased, and the performance as a heat exchanger is improved.

On the other hand, in the conventional laminated evaporator, as shown in FIG. 6B, the refrigerant is throttled between the adjacent beads 25, and the flow velocity increases. As a result, the degree of freedom of the flow is reduced, and the refrigerant flows in a predetermined direction indicated by an arrow in the drawing. Therefore, the refrigerant is
Since the air flows regardless of the area 24 shown in FIG. 2B, the area 24 becomes a stagnation area where the refrigerant does not move, and does not contribute to heat transfer.

As described above, according to the present embodiment, the heat exchange efficiency can be improved by eliminating the refrigerant stagnation that tends to occur on the upstream side of the bead while securing the durability of the laminated evaporator. .

The embodiments described above are not described to limit the present invention, and can be variously modified by those skilled in the art within the technical scope of the present invention. For example, in the above embodiment, the stacked evaporator has been described. However, the present invention is not limited to this, and it is needless to say that the present invention can be applied to other stacked heat exchangers.

[0038]

As described above, according to the present invention, the following effects can be obtained for each claim. According to the first aspect of the present invention, the durability of the stacked heat exchanger can be ensured, and the heat exchange efficiency can be improved by reliably eliminating the refrigerant stagnation that tends to occur on the upstream side of the bead. Can be done.

According to the second aspect of the invention, in addition to the effect of the first aspect, the thickness of the stacked heat exchanger in the air passage direction can be reduced.

According to the third aspect of the present invention, the flow of the refrigerant in the vicinity of the top of the bead becomes smooth, and a predetermined joining area in the bead between the plates can be secured, thereby improving the durability. Can be.

According to the fourth aspect of the present invention, the overall configuration of the air conditioner on which the stacked heat exchanger is mounted can be made compact, and the degree of freedom of the layout of the air conditioner is increased and the air conditioner is occupied. Space is small.

[Brief description of the drawings]

FIG. 1 is a side view of a laminated evaporator according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a liquid tube element and a heat transfer fin.

FIG. 3 is a cross-sectional view of a laminated evaporator.

FIG. 4 is a perspective view schematically showing a flow of a refrigerant in the laminated evaporator.

5A is a view of a bead formed on a plate as viewed from the top, FIG. 5B is a cross-sectional view taken along line XX of FIG. 5A, and FIG. 5C is a view of FIG. FIG. 3 is a cross-sectional view taken along line YY of FIG.

6A and 6B are diagrams schematically showing a measurement result of a flow state between beads, wherein FIG. 6A is a diagram showing a case of a laminated evaporator of the present embodiment, and FIG. 6B is a diagram of a conventional laminated evaporator; FIG.

7A and 7B are diagrams showing measurement results of a surface temperature distribution of a plate, wherein FIG. 7A shows a case of a laminated evaporator of the present embodiment, and FIG. 7B shows a case of a conventional laminated evaporator. It is.

FIG. 8 is a view schematically showing a flow state between beads of a conventional laminated evaporator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tank, 2 ... Liquid pipe element, 3 ... Heat transfer fin, 4 ... Integrated expansion valve, 10 ... Core part, 14 ... Refrigerant inlet hole, 15 ... Refrigerant outlet hole, 22 ... Refrigerant flow path, 25 ... Bead , 100: laminated evaporator (heat exchanger), P1, P2: plate.

Claims (4)

[Claims] 1. A liquid pipe element in which a pair of plates (P1, P2) are combined in the middle and a flow path (22) is formed inside.
(2) is a laminated heat exchanger having a core part (10) formed by laminating a plurality of layers via a heat transfer fin (3), wherein the pair of plates (P1, P2) includes: Each of the channels (2
2) A plurality of beads (25) protruding into and joined to each other are formed correspondingly, and the plurality of beads (25) are located at a bead position in a row of beads arranged in a direction perpendicular to the direction of the flow path (22). Are arranged so as to correspond to the positions between the beads of the adjacent bead rows, the pitch A in a direction perpendicular to the flow path (22) direction of the bead (25), the flow path (22) of the bead (25) Direction B, the width C of the hem of the bead (25) in the direction perpendicular to the flow path (22) direction, and the width D of the hem of the bead (25) in the flow path (22) direction is C < D, C <A, and 1 <B / A <1.3. 2. The pitch A, pitch B, width C, and width D are as follows: 3.4 mm ≦ A ≦ 3.95 mm, 4.0 mm ≦ B ≦ 4.5 mm, 3.0 mm ≦ C ≦ 3.9 mm, 2. The laminated heat exchanger according to claim 1, further satisfying the following relationship: 3.0 mm ≦ D ≦ 3.9 mm. 3. A width E of the top portion (26) of the bead (25) in a direction perpendicular to the direction of the flow path (22), and a width F of the top portion (26) of the bead (25) in the direction of the flow path (22). 3. The laminated heat exchanger according to claim 2, wherein the following relationship is satisfied: E ≦ F, 1.0 mm ≦ E ≦ 1.8 mm, and 1.0 mm ≦ F ≦ 1.8 mm. 4. The laminated heat exchanger according to claim 2, wherein the thickness G of the core portion in the direction in which the air passes is 45 mm ≦ G ≦ 60 mm.