JP6343183B2 - Flat tube for header plateless heat exchanger - Google Patents

Description

  The present invention relates to a flat tube of a header plateless heat exchanger.

The invention of the following patent document is disclosed about the flat tube used for a header plateless heat exchanger.
In the present invention, as shown in FIG. 7, a pair of first plate 21 and second plate 22 is bent into a groove shape, and the groove bottom portions 21a and 22a are fitted so as to face each other to form a flat tube 8. Is done. As for this 1st plate 21, the front-end | tip part of a pair of side wall part 21b is formed in a step inside, and the step part 21c is formed there. The tip end portion of the side wall portion 22b of the second plate 22 is fitted into the stepped portion 21c. Further, both opening end portions of the flat tube 8 are expanded in the thickness direction to form an expanded portion 23.

An inner fin 7 is usually interposed inside the flat tube 8. A dimple 6 is formed at an intermediate portion in the longitudinal direction of the flat tube 8 so as to protrude outward from the groove bottom portions 21a and 22a.
The height of the dimple 6 matches the expanded height of the expanded portion 23.
A large number of the flat tubes 8 are stacked in the thickness direction at the position of the widened portion 23 to constitute the core 10 of the heat exchanger. And the core fitting member 11, such as a casing and a tank, is fitted to the outer periphery of the core 10, and a heat exchanger is manufactured.

In such a core 10, the outer surfaces of the expanded portions 23 at both ends of the flat tube 8 are in contact with each other, a passage is formed in the middle portion in the longitudinal direction, and cooling water flows through the passage. And exhaust gas distribute | circulates the inside of the flat tube 8, and it is cooled with cooling water.
Since this heat exchanger is laminated in the thickness direction at the position of the expanded portion 23, there is a feature that a header plate is unnecessary, the number of parts is small, and assembly is easy.

JP 2011-163642 A

However, this flat plate for header plateless heat exchanger is divided into a flat tube 8 and a core fitting member 11 (in Patent Document 1, the casing is the core fitting member 11) vertically divided in the thickness direction. In addition, they are integrally brazed and fixed in a high-temperature furnace in a state where they are crimped together in the thickness direction. At that time, there is a possibility that abnormal deformation may occur at the joint between the pair of plates 21 and 22 in the expanded portion 23 of the flat tube 8.
That is, at the time of brazing, it is necessary to apply an external force in the thickness direction of each flat tube 8 to bring the plates 21 and 22 into close contact with each other. Then, as shown in FIG. 8, in the spread part 23, the end surface of the side wall part 22b of the 2nd plate 22 tends to slide down from the step part 21c. This is because the inner fin 7 is not interposed in the expanded portion 23 and the inside is hollow. In addition, the inner fin 7 is interposed other than the expansion part 23, and it supports the external force.

As a result, a gap is generated between the pair of plates 21 and 22 in the expanded portion 23 of each flat tube 8. When brazed in that state, a brazing failure occurs.
In addition, since the pair of plates 21 and 22 constituting such a flat tube 8 have different shapes, the quality control is not easy. Further, when the grooved plates are fitted by fitting, there is a drawback that their assembly is troublesome.
Accordingly, the present invention provides a flat tube for a header plateless heat exchanger that is easy to control and assemble a pair of plates, and that does not easily deviate from the side wall end of the flat tube even when an external force is applied in the thickness direction of the flat tube. The task is to do.

In the present invention according to claim 1, the pair of plates 1 are formed in the same shape by press molding,
Each plate 1 is bent into an L-shaped cross section by a bottom portion 1a and a side wall portion 1b provided on one side thereof, and at both ends in the longitudinal direction of each plate 1, the bottom portion 1a and the side wall portion 1b are is expanded outward in the thickness direction and expansion unit 2 is formed with a flared bottom 2a and the expansion side wall portion 2b,
The front edge of the side wall 1b forms an abutting surface 3a that is bent inward in parallel to the bottom 1a,
Wherein in the width direction of the front end edge of the bottom portion 1a, and the contact surface 4 is formed to match the contact surface 3a,
At least a part of the abutting surface 4 in the longitudinal direction is formed with a step 4b that is slightly recessed from the outer surface of the bottom portion 1a to prevent displacement in the width direction, and a convex portion that matches the step 4b. 3b is formed on the abutment surface 3a,
With the bottom 1a of the plate 1 are disposed opposite to each other so as to face the abutment surface 3a of the plate 1 abuts on the abutted surface 4 of the opposing plates 1, each A stepped positioning portion 5 is formed at the base of the bottom 1a of the plate 1 and the stepped portion 4b, and the leading edge of the convex portion 3b is brought into contact with the positioning portion 5 and fixed by brazing. This is a flat tube for a header plateless heat exchanger.

The present invention described in claim 2 is a flat tube for a header plateless heat exchanger according to claim 1,
The abutting surface (3a) has a concave surface (3d) that is concave with respect to the convex portion (3b) in the longitudinal direction, and a convex surface (4d) that matches the concave surface (3d). It is a flat plate for a header plateless heat exchanger that is provided on the abutting surface (4) and prevents the displacement in the longitudinal direction by the concave surface (3d) and the convex surface (4d).

According to a third aspect of the present invention, in the flat tube for a header plateless heat exchanger according to the first or second aspect,
An inner fin (7) is interposed between the pair of plates (1),
The tip edge of the contact surface (3a) of each plate (1) and / or the stepped portion (4a) of the contacted surface (4) contact the both end portions in the width direction of the inner fin (7), and the inner A flat plate for a header plateless heat exchanger, wherein the width direction of the fin (7) is positioned.

The flat plate for header plateless heat exchanger according to the present invention is a step in which a pair of plates 1 are formed by press molding into the same shape having an L-shaped cross section, and a protrusion 3b is provided on the abutting surface 3a. A portion 4 b is provided on the abutted surface 4, and a stepped positioning portion 5 is formed at the base of the bottom portion 1 a and the step portion 4 b of each plate 1, and a convex portion is formed on the positioning portion 5. The leading edge of 3b is abutted to prevent displacement in the width direction.

With this configuration, the flat tube 8 can be manufactured by one type of plate 1 having an L-shaped cross section. Furthermore, it is possible that the leading edge of the positioning portion 5 and the convex portion 3b of the stepped portion 4b to prevent displacement in the width direction by the this abutting, assembled precisely a pair of plates.
Moreover, since brazing is performed on a horizontal surface, the reliability of brazing is improved.

  In the above configuration, the contact surface (3a) is provided with a concave surface (3d), and a convex surface (4d) that matches the concave surface (3d) is provided on the contacted surface (4), and the concave surface (3d) If the longitudinal displacement is prevented by the convex surface (4d), the flat tube can be assembled more easily.

  Further, in any of the above-described configurations, the inner fin 7 is interposed between the pair of plates 1, and the tip surface of the contact surface 3 a of each plate 1 and / or the stepped portion 4 a of the contacted surface 4 is an inner fin. 7 is configured so as to be in contact with both end portions in the width direction, the width direction of the inner fin 7 can be positioned with a simple plate structure when the flat tube is assembled.

The disassembled perspective view which shows the Example of the flat tube for header plateless heat exchangers of this invention. The front view which shows the opening edge part of the flat tube. III-III arrow sectional drawing of FIG. FIG. 4 is a cross-sectional view taken along arrows IV-IV in FIG. 1. The principal part sectional drawing which shows a state when the flat tube 8 is laminated | stacked and the core 10 is formed. The VI section enlarged view of FIG. Sectional drawing (A) and a partially broken side view (B) of a conventional flat tube. Explanatory drawing which shows the shift | offset | difference of the side wall part when laminating | stacking and compressing a conventional flat tube.

Next, embodiments of the present invention will be described with reference to the drawings.
FIGS. 1-4 show the Example of the flat tube for header plateless heat exchangers of this invention, FIG. 5, FIG. 6 is explanatory drawing of the principal part of the core using the flat tube. For convenience of explanation, in FIG. 1, the lateral direction (left-right direction) of the plate 1 is defined as the width direction, and the depth direction perpendicular thereto is defined as the longitudinal direction.

(Structure of each plate 1)
The flat tube 8 of this application consists of a fitting body of a pair of plates 1 formed in the same shape by press molding.
As shown in FIG. 1, each plate 1 is bent into an L-shaped cross section, and has a bottom portion 1a and a side wall portion 1b. And the expansion part 2 which spreads in the outward direction of the bottom part 1a is formed in the both ends of the longitudinal direction of each plate 1. As shown in FIG. The expanded portion 2 includes an expanded bottom portion 2a and an expanded sidewall portion 2b.

The leading edge of the side wall 1b is bent in parallel to the bottom 1a side to form the contact surface 3a there. The abutment surface 3a has a convex portion 3b provided at the center thereof in the longitudinal direction, and concave surfaces 3d formed on both sides of the convex portion 3b so as to form a trapezoidal shape as a whole.
In addition, a band-shaped contact surface 4 is formed at the leading edges of the bottom 1a and the expanded bottom 2a. The abutted surface 4 is aligned with the abutting surface 3a. And the step part 4b which is slightly recessed from the outer surface of the bottom part 1a is formed in the intermediate part of this contacted surface 4 in the longitudinal direction. And the convex surface 4d is formed in the both sides of the longitudinal direction of the step part 4b.

  In addition, a large number of dimples 6 are formed on the bottom 1a of each plate 1 so as to protrude to the outer surface side. The height of the dimple 6 is the same as the expanded height of the expanded portion 2 of each plate 1.

In this example, the convex part 3b of the intermediate part of the longitudinal direction of the contact surface 3a of each plate 1 fits into the recessed step part 4b of the to-be-contacted surface 4, and has a width direction shift stop function.
That is, as shown in FIG. 4, the stepped portion 4 b slightly protrudes from the outer surface of the bottom portion 1 a in the thickness direction, and the convex portion 3 b is fitted therein, so that the positioning portion 5 in the width direction is formed.

(Assembly of flat tube 8)
As shown in FIG. 1, the pair of identically shaped plates 1 formed in this way are arranged in opposite directions so that their bottoms 1 a face each other, and with the inner fins 7 interposed, the flat tubes 8. Configure.
2 to 4 show the contact surfaces 3a and 3c and the contacted surface 4 in each part (the expanding part 2 is shown in FIG. 2, the step part 4a is shown in FIG. 3, and the step part 4b in the longitudinal intermediate position is shown in FIG. 4). 4c shows a state of contact with 4c.

In FIG. 2, the contact surface 4c of the expanded side wall 2b of the upper plate 1 is in contact with the contact surface 4c of the expanded bottom 2a of the lower plate 1, and the contact of the lower plate 1 is contacted on the right. The contact surface 4c of the upper plate 1 is in contact with the contact surface 3c.
On the left side of the cross section shown in FIG. 4, the lower surface of the convex portion 3 b of the upper plate 1 is in contact with the upper surface of the step portion 4 b of the lower plate 1, and the tip surface of the convex portion 3 b is in contact with the positioning portion 5. Thus, the side wall 1b of each plate 1 is configured not to be displaced in the width direction.

On the right side, the upper surface of the convex portion 3 b of the lower plate 1 is in contact with the lower surface of the step portion 4 b of the upper plate 1, and the tip surface of the convex portion 3 b is in contact with the positioning portion 5. In this way, the plates 1 are brought into contact with each other at the horizontal surface of the edge in the width direction and brazed at that portion. Therefore, the brazing material is held on the horizontal plane.
On the other hand, if the plates are brought into contact with each other on a vertical surface and brazed as in the prior art, the brazing material may leak in the direction of gravity.

(Inner fin 7 positioning structure)
In FIG. 3, when the flat tube 8 is assembled, first, the plate 1 constituting the lower surface is arranged, and the inner fin 7 is placed thereon. At this time, one lower edge (left side) of the inner fin 7 in the width direction contacts the step 4a of the plate 1, and the other upper edge (right side) contacts the tip surface of the contact surface 3a. . Therefore, temporary positioning of both side edges in the width direction of the inner fin 7 is possible. Thereafter, the upper plate 1 is fitted. At that time, the upper edge of the inner fin 7 is further positioned in the width direction by the step 4a of the plate 1 on the upper surface side.

  In this example, the inner fins 7 are described as rectangular wave-shaped straight fins, but known ones such as trapezoidal wave-shaped, sine wave-shaped straight fins, wave fins, and offset fins can be used.

(Assembling the heat exchanger)
The flat tubes 8 formed in this way are laminated in the thickness direction by the widened portion 4 and the tops of the dimples 6 to constitute the core 10 of the heat exchanger as shown in FIGS. Then, the core fitting member 11 is fitted on the outer periphery of the core 10.
As an example, when the core fitting member 11 is a casing, the casing can be formed of a pair of groove-like members, and can be fitted to each other at an intermediate portion in the stacking direction. A pair of cooling water inlets / outlets (not shown) are formed in the side wall of the casing, and pipes are connected thereto. A pair of tanks are arranged at both ends of the core 10 in the opening direction.

The heat exchanger assembled in this way is brazed in the furnace with an external force applied in the stacking direction of the cores 10. As a method of brazing, brazing material is clad on one of the parts which are in contact with each other, or brazing material is interposed or applied between them.
Although the core fitting member 11 has been described as a casing in this example, it is also possible to first fit the open end of the core 10 with a tank, and then fit the core and the outer periphery of the tank with a casing.

(Action during brazing)
As shown in FIG. 5 and FIG. 6, since it contacts with the inner surface of the core fitting member 11 in the plane of the side wall portion 1b and the expanded side wall portion 2b, highly reliable brazing is realized.
Further, as shown in FIG. 6, the expanded bottom portion 2 a is also formed flat up to the abutted surface 4 c, and the end surface thereof is cut out at the corner, and is flush with the outer surface of the expanded side wall portion 2 b of the opposing plate 1. Is consistent. And the end surface contacts the inner surface of the core fitting member 11.
Therefore, the gap between the core fitting member 11 and the flat tube 8 can be made half of the gap shown in FIG. That is, the gap generated by the corner portion 9 of the flat tube 8 can be easily closed with the brazing material during brazing. In addition, it is possible to provide a highly reliable header plateless heat exchanger that is unlikely to leak due to brazing during brazing.

DESCRIPTION OF SYMBOLS 1 Plate 1a Bottom part 1b Side wall part 2 Expanded part 2a Expanded bottom part 2b Expanded side wall part 3a Contact surface 3b Convex part 3c Contact surface 3d Concave surface

4 Contact surface 4a Step portion 4b Step portion 4c Contact surface 4d Convex surface 5 Positioning portion

6 Dimple 7 Inner fin 8 Flat tube 9 Corner portion 10 Core 11 Core fitting member

21 1st plate 21a Groove bottom part 21b Side wall part 21c Step part 22 2nd plate 22a Groove bottom part 22b Side wall part 23 Widening part

Claims (3)

A pair of plates (1) are formed in the same shape by press molding,
Each plate (1) is bent into an L-shaped cross section by a bottom portion (1a) and a side wall portion (1b) provided on one side thereof, and at both ends in the longitudinal direction of each plate (1), bottom (1a) and side wall (1b) it is being expanded outward in the thickness direction and expanded portions having diverging bottom (2a) and diverging side wall portion (2b) (2) is formed ,
The tip edge of the side wall (1b) forms an abutting surface (3a) that is bent inward parallel to the bottom (1a),
It said bottom in the widthwise direction of the leading edge of (1a), and the contact surface (4) is formed to match the contact surface (3a),
At least a part of the abutted surface (4) in the longitudinal direction is slightly recessed from the outer surface of the bottom (1a) to form a step (4b) that prevents displacement in the width direction. protrusion that matches the (4b) (3b) is formed wherein the abutment surface (3a),
The plates (1) are arranged in opposite directions so that the bottoms (1a) of the plates (1) face each other, and the abutting surfaces (3a) of the plates (1) are in contact with the opposed plates (1). In contact with the surface (4) ,
A stepped positioning part (5) is formed at the base of the bottom part (1a) and the step part (4b) of each plate (1), and the tip of the convex part (3b) is formed in the positioning part (5). A flat tube for a header plateless heat exchanger, wherein the edge is abutted and fixed by brazing. In the flat plate for header plateless heat exchangers according to claim 1,
The abutting surface (3a) has a concave surface (3d) that is concave with respect to the convex portion (3b) in the longitudinal direction, and a convex surface (4d) that matches the concave surface (3d). A flat plate for a header plateless heat exchanger, which is provided on the contact surface (4) and prevents the displacement in the longitudinal direction by the concave surface (3d) and the convex surface (4d). In the flat plate for header plateless heat exchangers according to claim 1,
An inner fin (7) is interposed between the pair of plates (1),
The leading edge of the abutting surface (3a) of each plate (1) and / or the stepped portion (4a) of the abutted surface (4) abuts on both ends in the width direction of the inner fin (7), A flat plate for a header plateless heat exchanger, characterized by positioning the width direction of the inner fin (7).

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