JP2560340B2 - Stacked heat exchanger - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminated heat exchanger formed by laminating a large number of flat tubes in which two core plates are joined.

[Prior Art] Generally, for example, in the case of a refrigerant evaporator used in an air conditioner for an automobile, a laminated heat exchanger has a shallow tray shape made of an aluminum plate, as shown in FIG. A flat tube 101 is formed by joining two core plates 100 each having a portion facing each other, and a large number of the flat tubes 101 are stacked to form a core of a refrigerant evaporator.

The flat tube 101 includes a refrigerant tank 102 and a refrigerant passage 103.
Are formed, and when the flat tubes 101 are stacked, the refrigerant tanks 102 of the respective flat tubes 101 are provided so as to communicate with each other. Fins 104 for heat transfer are attached between the refrigerant passages 103 of each flat tube 101 in order to improve heat exchange performance. The specific flat tube 101 is formed with a refrigerant inflow pipe serving as a refrigerant inlet passage into the refrigerant evaporator, and a refrigerant outflow pipe serving as a refrigerant outlet passage from the refrigerant evaporator,
On the outside of the flat tubes 101 arranged at both ends of the core,
A side plate 105 as a reinforcing plate is arranged. Under such a structure, they are integrally brazed and joined together.

When the refrigerant flows into the refrigerant evaporator assembled as described above, the inflowing refrigerant pressure serves as a force for separating the core plates 100 forming the flat tubes 101 from each other. Particularly, in the refrigerant tank 102, since the joint portion is only the peripheral portion of the refrigerant tank 102 and does not exist inside the refrigerant tank 102, the pressure resistance strength of the refrigerant tank 102 is lower than that of the other portions. The force applied to the core plates 100 other than the core plates (hereinafter referred to as the end plates 106) adjacent to the side plates 105 also acts on the adjacent flat tubes 101 to separate the core plates 100 from each other. As a result, the force of separating the core plates 100 from each other is offset by the force of separating the adjacent core plates 100 from each other.

However, since the end plate 106 does not have the adjacent flat tubes 101, the forces that separate the core plate 100 and the end plate 106 are not offset, and the stress generated in the end plate 106 is the stress generated in the other core plate 100. Will be larger than In particular, as shown in FIG. 8, stress concentration occurs in the parts A and B. For this reason,
It is necessary to increase the pressure resistance of the end plate 106 as compared with other core plates 100.

For this reason, conventionally, for example, the pressure strength is increased by increasing the plate thickness of the end plate 106 to about 3 times the plate thickness of the other core plates 100.

[Problems to be Solved by the Invention] However, since the plate thickness of the end plate 106 is increased, the weight of the refrigerant evaporator is increased.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a lightweight laminated heat exchanger by finding a shape that improves the pressure resistance of an end plate.

[Means for Solving Problems] In order to achieve the above-mentioned object, the present invention has a tray-like portion that constitutes a heat transfer medium tank, a plate-like portion that constitutes a heat exchange passage, the tray-like portion and the plate. A core having a large number of flat tubes laminated by facing and joining two core plates each having a joining flange portion formed on the outer edge of the groove, a side plate attached to an end portion of the core, and the heat exchange. In a laminated heat exchanger including fins provided between each of the passages and between the heat exchange passage and the side plate, the core plate adjacent to the side plate is joined to the tray portion and the joint. The radius of curvature R1 of the boundary with the flange for use is set to the minimum value for forming the core plate, and the depth h of the tray is the length L of the heat transfer medium tank in the longitudinal direction. Sometimes between L / 5 and L / 2, and , The distance from the joint surface of the flat tube adjacent to the side plate to the inner surface of the side plate is equal to or less than H, and the radius R2 of the curved surface of the tray is set to the maximum value that can be taken within the constraint. The provision is provided as a technical means.

[Operation and Effect of the Invention] In the present invention having the above-described configuration, the shape of the heat transfer medium tank of the core plate adjacent to the side plate is set to a value in the most desirable range obtained based on experiments, It is possible to reduce stress concentration due to the heat transfer medium applied to the heat transfer medium tank of the core plate adjacent to the plate.

As a result, the compressive strength of the core plate adjacent to the side plate is improved, so that even if the thickness of the core plate is reduced, it is possible to obtain the same compressive strength as that of the conventional core plate. Then, by reducing the thickness of the core plate, it is possible to reduce the weight of the laminated heat exchanger.

[Embodiment] Next, a refrigerant evaporator as a laminated heat exchanger of the present invention will be described based on an embodiment shown in the drawings.

FIG. 1 is an enlarged sectional view of a side tank portion of a laminated refrigerant evaporator, FIG. 2 is a front view of the laminated refrigerant evaporator, and FIG. 3 is a sectional view of a flat tube constituting the laminated refrigerant evaporator. Four
The figure shows a front view of a core plate constituting a flat tube.

As shown in FIG. 2, the laminated refrigerant evaporator 1 of this embodiment is formed by combining a plurality of flat tubes 2 in a laminated shape.

The flat tube 2 has a thickness of 0.3 to 0.8 mm and a material plate in which a brazing material such as A4004 is clad in advance on the surface of an aluminum plate or the like of material A3003, as shown in FIG.
It is formed by press-molding the core plate 3 in the shallow basin portion and joining the two press-molded core plates 3 with their concave sides facing each other.

As shown in FIG. 4, the core plate 3 forms two tray-shaped portions 3a and plate-shaped portions 3b, and the plate-shaped portion 3b has its lower end at the center in the longitudinal direction (vertical direction in FIG. 4). Partition wall 4
Is provided. As a result, the two core plates 3
When the flat tube 2 is configured with, each plate-shaped portion 3b
As a result, the refrigerant passage 5 (shown by the double-dotted chain line arrow in FIG. 4) which is the heat exchange passage of the present invention is formed in a U shape. The basin portions 3a that contact both end portions of the refrigerant passage 5 (upper left and right in FIG. 4) are
It is configured as a refrigerant tank 6 which is a heat transfer medium tank of the present invention, and a port portion 6a serving as a refrigerant inlet / outlet is formed substantially at the center of the tray 3a.

The core plate 3 is provided with a large number of ribs 7 having a short jetty shape in the same direction, and the ribs 7 of the two core plates 3 constituting one flat tube 2 are attached to each other in an X shape. It is brazed and joined under the condition.

By adopting such a structure, the flat tube 2
Since the flow of the refrigerant flowing inside is zigzag, the heat exchange performance can be greatly improved and the strength of the flat tube 2 can be increased.

At the peripheral edge of the core plate 3, a joining flange portion 8 is provided as a brazing joining surface when the flat tube 2 is formed. Further, as shown in FIG. 3, the lower end portion of the joining flange portion 8 is horizontally bent to the outside of the core plate 3, and the tip end portion thereof is bent downward, so that the flat tube 2 adjacent to the flat tube 2 is It has a function as a spacer for keeping the space 9 for heat exchange formed between them to have a predetermined width.

As shown in FIG. 2, a plurality of flat tubes 2 configured as described above are laminated so that the port portions 6a of adjacent flat tubes 2 are overlapped with each other to form the core 10, and each adjacent flat tube is formed. Corrugated fins 11 are sandwiched in respective heat exchange spaces 9 formed by the second port portion 6a and the lower end portion of the joining flange portion 8.

The corrugated fins 11 are formed by bending an extremely thin aluminum plate into a wavy shape with a pitch width of about 4.0 mm in order to improve the heat exchange performance of the refrigerant.

Side plates 12 as reinforcing plates are attached to both ends of the core 10, and corrugated fins 11 are arranged between the side plates 12 and the refrigerant passages 5 of the flat tubes 2.

Of the two core plates 3 forming the flat tube 2 adjacent to the side plate 12, the side plate
Core plate 3 arranged on the 12 side (hereinafter referred to as end plate
13) is not formed with the port portion 6a and has a different shape from the other core plates 3. The shape of the end plate 13 will be described later.

A specific flat tube 2 is provided in the vicinity of the approximate center of the refrigerant evaporator 1 formed by combining a plurality of flat tubes 2 in a laminated form.
A refrigerant inflow pipe 14 serving as a refrigerant inlet into the refrigerant evaporator 1 and a refrigerant outflow pipe 15 serving as a refrigerant outlet from the refrigerant evaporator 1 are formed integrally with a and 2b.

The free ends of the refrigerant inflow pipe 14 and the refrigerant outflow pipe 15 are connected to a box type expansion valve 17 via a joint member 16.

 Next, the shape of the end plate 13 will be described.

In the refrigerant tank 6 of the flat tube 2 adjacent to the side plate 12 (hereinafter referred to as the side tank 18), the stress distribution generated with respect to the refrigerant pressure flowing into the side tank 18 was examined by an experiment, and as a result, the conventional end plate In the shape of 106, as shown in FIG. 8, stress concentration occurs in the portions A and B.

From this, the relationship between each dimension of the end plate 13 which will be described later and the generated stress is found experimentally, and the shape of the end plate 13 is determined.

First, as shown in FIG. 1, in the longitudinal cross section of the end plate 13, the boundary curvature radius between the tray portion 3a of the end plate 13 and the joining flange portion 8 is R1, the curvature surface radius of the tray portion 3a is When the depth of R2 and the basin 3a is h, the change in the value of each dimension R1, R2, h and the corresponding part A and B
The magnitude of the stress generated in the part is shown in the graphs of FIGS. 5, 6, and 7.

In the relationship between the R1 dimension and the generated stress shown in FIG. 5, the generated stress also decreases as the R1 dimension decreases. In the relationship between the R2 dimension and the generated stress shown in FIG. 6, the generated stress decreases as the R2 dimension increases. In the relationship between the h dimension and the generated stress shown in FIG. 7, when the length of the side tank 18 in the longitudinal direction is L, the generated stress is small between L / 5 and L / 2. End plate 13 when h dimension is L / 2
The basin 3a has a hemispherical shape, and the generated stress shows the minimum value.

If the distance h from the joint surface of the flat tube 2 adjacent to the side plate 12 to the inner surface of the side plate 12 is H, and the depth h of the tray 3a becomes larger than the H dimension, the side tank 18 is most likely to move. Since it protrudes from the corrugated fins 11 arranged on the outside, it becomes difficult to temporarily assemble the refrigerant evaporator 1 with a jig during brazing and assembling. Further, since it jumps out from the corrugated fin 11, it becomes easy to receive external pressure. From these things, h dimension is assumed to be H dimension or less.

Based on the above experimental results, the R1
Is set to the minimum value for forming, h dimension is set between L / 5 and L / 2 and less than H dimension, and R2 dimension is set to R1 dimension and h
Set to the maximum value that can be taken within the dimensional constraints End plate
Determine the shape of 13.

The method for assembling the laminated refrigerant evaporator 1 having the structure as described above is such that both surfaces of each core plate 3 and the side plates 12 are clad with a brazing material in advance,
The corrugated fins 11 and the joint member 16 are superposed or fitted in a laminated state in the state shown in FIG. 2 to temporarily assemble the refrigerant evaporator 1. This state is fastened and fixed using a jig and then heated to the melting temperature of the brazing material in the brazing furnace to complete the brazing assembly.

As described above, by setting each dimension of the end plate 13 to a value in the most desirable range obtained based on the experiment and determining the shape of the end plate 13, it is possible to reduce the refrigerant load applied to the end plate 13. it can. As a result, with respect to the load of the refrigerant, the A portion of the side tank 18,
It is possible to reduce the magnitude of the stress generated in the section B and the section B.

Therefore, even if the pressure strength of the end plate 13 is improved and the plate thickness of the end plate 13 is reduced, the same pressure resistance strength as the conventional end plate 13 can be obtained (according to the experiment, Even if it is thinned to about 25%, the same compressive strength can be obtained). Then, by making the plate thickness of the end plate 13 thin, it is possible to reduce the weight of the laminated heat exchanger 1.

The side plate 12 may have a shape along the end plate 13 (one-dot chain line in the drawing) or a linear shape (solid line in the drawing) as shown in FIG.

In this embodiment, the refrigerant inflow pipe 14 and the refrigerant outflow pipe 15
Although the case of arranging and at approximately the center of the refrigerant evaporator 1 is illustrated, it is also possible to dispose at and at one end of the core 10 and form the end plate 13 of this embodiment at the other end. good.

In addition, the refrigerant tank 6 formed in the flat tube 2 is
Although the case where it is arranged adjacent to the upper side (upper side in FIG. 2) of the refrigerant evaporator 1 is illustrated, it may be arranged separately on the upper side and the lower side of the refrigerant evaporator 1.

Although the laminated heat exchanger of the present invention has been described as a refrigerant evaporator, a refrigerant condenser of an air conditioner, a hot water heater core,
Alternatively, it may be used for a radiator or the like.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a side tank portion of the laminated refrigerant evaporator of the present invention, FIG. 2 is a front view of the laminated refrigerant evaporator, and FIG.
The figure is a cross-sectional view of a flat tube that constitutes the laminated refrigerant evaporator, Fig. 4 is a front view of the core plate that constitutes the flat tube, and Fig. 5 is a graph showing the relationship between the R1 dimension and the generated stress. FIG. 7 is a graph showing the relationship between the R2 dimension and the generated stress, FIG. 7 is a graph showing the relationship between the h dimension and the generated stress, and FIG. 8 is a cross-sectional view of the main parts of a conventional laminated refrigerant evaporator. . In the figure, 1 ... Laminated refrigerant evaporator, 2 ... Flat tube,
3 ... core plate, 3a ... tray-like part, 3b ... plate-like part, 5
…… Refrigerant passage (heat exchange passage), 6 …… Refrigerant tank (heat transfer medium tank), 8 …… Joint flange, 10 …… Core, 11 …… Corrugated fin, 12 …… Side plate,
13 …… End plate, 18 …… Side tank

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masatoshi Suto 1-1, Showa-cho, Kariya city, Aichi Japan Denso Co., Ltd. (56) References JP 61-184394 (JP, A) JP 61- 173097 (JP, A) Actually opened 64-31371 (JP, U)

Claims (1)

(57) [Claims] 1. A core plate comprising a tray-like portion constituting a heat transfer medium tank, a plate-like portion constituting a heat exchange passage, and a joining flange portion formed on an outer edge of the tray-like portion and the plate-like portion. A core having a large number of flat tubes laminated by facing each other, a side plate attached to an end of the core, a space between each of the heat exchange passages, and the heat exchange passage and the side plate. In the laminated heat exchanger including a fin provided therebetween, the core plate adjacent to the side plate has a boundary curvature radius R1 between the tray-shaped portion and the joining flange portion.
Is set to the minimum value for forming the core plate, and the depth h of the tray is L / 5 to L / 2, where L is the length in the longitudinal direction of the heat transfer medium tank. Between the flat plate adjacent to the side plate and the inner surface of the side plate to a distance H or less, and the radius R2 of the curved surface of the tray is within the constraint. A laminated heat exchanger having a maximum possible value.