JP2022038987A - Joint structure of header plate and flat tube of heat exchanger - Google Patents

Abstract

To decrease inflow resistance of a heat exchange fluid of a flat tube 3 having inner fins 4.SOLUTION: A wide part 2a is formed only at an axial intermediate part of a tube insertion hole 2 of a header plate 1 in advance and an expanded part 3a of an intermediate part of an end part of a flat tube 3 is crimped to the wide part 2a.SELECTED DRAWING: Figure 1

Description

The present invention relates to a heat exchanger having inner fins in a flat tube constituting the heat exchanger core, in which the internal ventilation resistance of the core is reduced.

The following Patent Documents 1 and 2 describe a heat exchanger in which a core is formed by a flat tube having an inner fin, a heat exchange fluid is circulated in the flat tube, and the heat exchanger is cooled.

Japanese Unexamined Patent Publication No. 2004-263616 Japanese Unexamined Patent Publication No. 2006-284004

When the heat exchange fluid is supplied to the flat tube having the inner fin, the inflow resistance of the heat exchange fluid at the inlet of the flat tube becomes large, and there is a drawback that the heat exchange performance is deteriorated.
Therefore, it is an object of the present invention to provide a heat exchanger that reduces the inflow resistance of the heat exchange fluid of a flat tube having an inner fin as much as possible.

According to the first aspect of the present invention, the end portion of the flat tube 3 is inserted into the tube insertion hole 2 of the header plate 1, the end portion thereof is expanded, and the flat tube 3 and the header plate 1 are joined. In the joint structure of the header plate of the heat exchanger and the flat tube
The tube insertion hole 2 has an axis L of the tube insertion hole 2 in the width direction of the header plate 1, and a wide portion 2a in which the width of only the intermediate portion in the axis direction is formed wider than both ends in advance. Have and
The intermediate portion of the end portion of the flat tube 3 is expanded to form an expanded portion 3a, and the outer periphery of the expanded portion 3a is crimped to the wide portion 2a of the tube insertion hole 2. It is a joint structure of the header plate of the exchanger and the flat tube.

The present invention according to claim 2 is the joint structure between the header plate of the heat exchanger and the flat tube according to claim 1.
The inner fin 4 is built in the flat tube 3, and the cut portion 4a is cut in advance only in the middle portion in the axial direction of the end portion of the inner fin 4, and the widened portion 3a of the flat tube 3 is provided at the cut portion 4a. It is a joint structure of the header plate of the heat exchanger and the flat tube in which the above is formed.

The present invention according to claim 3 is the joint structure between the header plate of the heat exchanger and the flat tube according to claim 1 or 2.
The expanded portion 3a of the flat tube 3 is formed in the shape of a flat drum that gradually swells from both ends toward the center, and the area of the cross section thereof is reduced as the distance from the end of the tube insertion hole 2 increases. It is a joint structure of a header plate and a flat tube.

According to the first aspect of the present invention, a wide portion 2a is formed in advance only in the middle portion of the tube insertion hole 2 of the header plate 1, and the wide portion 2a is formed in the middle portion of the end portion of the flat tube 3. The portion 3a is crimped.
In this way, when the outer circumference of the widened portion 3a of the flat tube 3 is pressed against the wide portion 2a in the middle of the end of the tube insertion hole 2, the inflow resistance of the heat exchange fluid at the inlet of the flat tube 3 is significantly increased. To reduce. At the same time, the expanded portion 3a of the flat tube 3 is pressed against the wide portion 2a of the tube insertion hole 2, and the strength of the joint portion between the header plate 1 and the flat tube 3 can be improved. Further, the stress applied to the end portion of the flat tube 3 can be dispersed to the widened portion 3a and the wide portion 2a to improve the durability of the heat exchanger.

In the invention according to claim 2, the inner fin 4 is incorporated in the flat tube 3, the cut portion 4a is cut in advance only in the middle portion of the end portion thereof, and the flat tube 3 is expanded at the cut portion 4a. It is an invention.
By expanding the cut portion 4a, the flat tube 3 can be expanded without being disturbed by the inner fin 4, and the heat exchange fluid can be smoothly distributed. Further, since the cut portion 4a is provided only in the intermediate portion and the inner fins 4 remain at both ends, the rigidity of the entire flat tube 3 can be ensured.

According to the third aspect of the present invention, the expanded portion 3a of the flat tube 3 is formed in a flat drum shape gradually swelling from both ends toward the center, and the area of the cross section thereof is separated from the end portion of the tube insertion hole. It will shrink as much as possible.
By doing so, the rigidity of the expanded portion 3a of the flat tube 3 can be increased. Further, the flat tube 3 can be expanded without difficulty to facilitate the flow of the heat exchange fluid.

The main parts of the heat exchanger of the present invention are shown, (A) is a plan view thereof, (B) is a cross-sectional view taken along the line BB of (A), and (C) is a cross-sectional view taken along the line CC of (B). figure. Explanatory drawing of the flat tube 3 of the same heat exchanger and the inner fin 4 inserted into it. Explanatory drawing which shows the assembly procedure of the core of the heat exchanger. It is an assembly explanatory view of the header plate 1 and the flat tube 3 of the heat exchanger, (A) (B) show the state before the assembly, and (C) (D) show the state after assembly. Is shown. A perspective view of a main part showing the assembled state of the heat exchanger.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a main part of the core of the heat exchanger of the present invention, (A) is a plan view thereof, (B) is a sectional view taken along the line BB of (A), and (C) is C of (B). -C is a cross-sectional view taken along the arrow. Further, FIG. 2 is an explanatory diagram showing the relationship between the flat tube 3 used in the heat exchanger and the inner fin 4, and FIG. 3 is an explanatory diagram showing the procedure for assembling the header plate 1 and the flat tube 3 of the heat exchanger. FIG. 4 is an explanatory view of the assembly, and FIG. 5 is a perspective view of the main part after the assembly.
INDUSTRIAL APPLICABILITY In a heat exchanger having an inner fin 4 inside a parallel flat tube 3 such as an EGR cooler or a condenser, the present invention reduces the flow resistance of the flat tube 3 at least on the inlet side of the heat exchange fluid. The purpose.
FIG. 5 is a perspective view of a main part of the heat exchanger of the present invention, which has a large number of parallel flat tubes 3 and a header plate 1 through which both ends thereof are inserted, and an outer fin 7 is arranged in each flat tube 3. It was done.

[Characteristics of the invention]
In FIG. 3, a wide portion 2a is formed in an axial middle portion of a large number of tube insertion holes 2 previously formed in the header plate 1, and both ends of a flat tube 3 having an inner fin 4 are inserted therein (lower). Side omitted). Next, as shown in FIGS. 4 (B) and 4 (C), the expander 8 is inserted into the open end of the flat tube 3, and the end of the flat tube 3 is expanded as shown in FIGS. 4 (C) and 4 (D). To form the expansion portion 3a. Then, the expanded portion 3a is pressed against the wide portion 2a of the header plate 1. In this expansion step, the outer circumferences of both ends in the axial direction in the cross section of each flat tube 3 are maintained.
A brazing material is coated or applied to either the flat tube 3 or the header plate 1. Next, the outer fins 7 are arranged between the flat tubes 3 and inserted into the furnace in a state where the whole is assembled, and the parts are brazed integrally.

In this example, as shown in FIG. 2, both ends of the inner fin 4 are cut into a V-shaped side surface to form a cut portion 4a. After inserting such an inner fin 4 into the flat tube 3, the flat tube 3 is expanded at the excision portion 4a. The shape of the expander 8 is formed so that the outer peripheral surface thereof matches the wide portion 2a after the flat tube 3 is expanded.
At this time, the expanded portion 3a is formed in the shape of a flat drum that gradually swells from both ends toward the center in FIG. At the same time, each cross section of the end of the flat tube 3 shrinks as its area moves away from the end of the tube insertion hole 2. Then, the outer circumference of the expanded portion 3a is pressed against the wide portion 2a of the tube insertion hole 2 of the header plate 1. As the cross section of the expanding tool 8 for that purpose, one that is aligned with or slightly larger than the outer periphery of the expanding portion 3a is used.
Next, in this example, the claw portion 1b (FIG. 3) on the outer periphery of the header plate 1 is caulked as shown in FIG. 1 (A) to form the caulked portion 1a. At this time, a seal ring 6 is interposed between the tank body 5 and the annular groove of the header plate 1 as shown in FIG. 1 (B).

In the embodiment of the drawing, the widened portion 3a and the wide portion 2a of only the upper header plate 1 are displayed, but this can also be done with the lower header plate 1.
Furthermore, they may be formed only on the upper header plate 1.
In this example, the upper header plate 1 and the tank body 5 form an inflow tank for heat exchange fluid.

[Modification example]
The shape of the cut portion of the inner fin 4 is not limited to the above implementation, and may be U-shaped in a side view.

The present invention can be used for a heat exchanger in which a core is formed by a large number of flat tubes 3 having inner fins 4, and a heat exchange fluid flows in the flat tubes 3, such as an EGR cooler and a condenser, as well as an oil cooler.

1 Header plate 1a Caulking part 1b Claw part 2 Tube insertion hole 2a Wide part 3 Flat tube 3a Expanded part

4 Inner fin 4a Excision part 5 Tank body 6 Seal ring 7 Outer fin 8 Expansion tool

Claims (3)

The end of the flat tube (3) is inserted into the tube insertion hole (2) of the header plate (1), the end is widened, and the flat tube (3) and the header plate (1) are joined. In the joint structure of the header plate of the heat exchanger and the flat tube
The tube insertion hole (2) has an axis L of the tube insertion hole (2) in the width direction of the header plate (1), and the width of only the middle portion in the axis direction is formed wider in advance than both ends. Has a wide portion (2a)
The intermediate portion of the end portion of the flat tube (3) is expanded to form an expanded portion (3a), and the outer periphery of the expanded portion (3a) is a wide portion (2a) of the tube insertion hole (2). The joint structure of the header plate of the heat exchanger and the flat tube, which is characterized by being crimped to. In the joint structure of the header plate of the heat exchanger and the flat tube according to claim 1.
The flat tube (3) is provided with an inner fin (4), and has a pre-cut cut portion (4a) only in the middle portion in the axial direction of the end portion of the inner fin (4), and the cut portion (4a) is provided. A joint structure between the header plate of the heat exchanger and the flat tube in which the expanded portion (3a) of the flat tube (3) is formed. In the joint structure between the header plate of the heat exchanger and the flat tube according to claim 1 or 2.
The expanded portion (3a) of the flat tube (3) is formed in a flat drum shape that gradually swells from both ends toward the center, and the cross-sectional area thereof is separated from the end portion of the tube insertion hole (2). A shrinking heat exchanger header plate and flat tube joint structure.

Images