Not applicable.
Not applicable.
Not applicable.
The present invention is directed toward heat exchangers, and particularly toward heat exchanger manifolds having corners therein and the manufacture of such manifolds.
Heat exchangers are known of a variety of configurations, including EP 1 004 841 A2, which has a plurality of tubes connected to a manifold which is formed of a header, closure caps and a tank closure, the individual parts being produced from solder-coated aluminum sheets, which are assembled into a heat exchanger. Process-reliable manufacture of such heat exchangers may be difficult, however, because the connection of the components, particularly at corners formed of three parts, is difficult to manage.
Heat exchangers for vehicles, such as radiators, have been state-of-the-art for many decades and have proven themselves to be reliably producible and functionally reliable as well. An example is described in German Utility Model 7 229 162, in which the tube bottom is divided into several small segments.
However, the collecting tanks or manifolds are often made of plastic and fastened mechanically on the peripheral edge of the bottom of the tubes. Since such tube bottoms have a distinct protrusion above the heat exchanger core (generally consisting of flat tubes and corrugated ribs), such structures can require relatively significant incorporation space, which can be undesirable in instances where space is limited, such as in vehicle engine compartments. Recycling is also hampered, because of the use of different material.
There are and have been many proposals, and heat exchangers consisting completely of aluminum are also already in use for vehicles, in which the weight and the required incorporation space of vehicle heat exchangers have been further reduced by omitting the tube bottom. DE 38 34 822 A1 is representative in this regard. Such solutions require deformation of the ends of the flat tubes in order to be able to join them to the walls of the collecting tank or manifold in sealed fashion. The manufacturing process in such heat exchangers can still, however, be problematic, particularly the tight solder connection, and the manufacturing cost caused by deformation of the tube ends. The necessary use of high-grade materials with very good deformation properties also cannot be overlooked.
It has been proposed, including in DE 197 22 098 A1, to lengthen the side parts on both ends and to close the front ends of the collecting tanks with these extensions. An additional reduction in the number of individual parts was achieved with this expedient, and a costly deep drawing die need not be prescribed for production of the collecting tanks, because the collecting tanks need have only two bevelings or flanges running in the longitudinal direction, which can be accomplished with a relatively simple bending tool.
A heat exchanger with collecting tanks have a rectangular profile in cross section is described in DE 1 277 282. The flat tube ends are deformed in order to be able to solder them in the profile, and the end openings of the collecting tanks are closed by individual caps. A tube bottom is not required there as an individual part.
A coolant condenser is described in DE 195 36 999 A1, which also shows caps closing the front openings of the collecting tanks. Since the collecting tanks and the coolant condenser are in two parts, one part can be viewed as the tube bottom, since it has openings in which the ends of the flat tubes are arranged, and the other part can be viewed as the tank. Both parts are joined on a common soldering edge.
Side parts, whose ends each extend in a slit provided on the ends of the collecting tubes, are shown in EP 0 882 940 A2, in which a condenser of an air conditioner is described. However, the ends do not close the entire cross section of the collecting tubes. A situation is only achieved in which the integrity of the heat exchanger is improved. Since the collecting tanks are designed as tubes, this heat exchanger has no tube bottom as an individual part, as stated in the preamble.
This developmental trend briefly sketched on the example of condensers, however, has not been pursued in heat exchangers for vehicles, like water coolers or charge-air coolers, since the direction described further above is being pursued there and the tube bottom has been abandoned, so that a developmental direction that has also long been known has been resumed again and pursued.
The present invention is directed toward overcoming one or more of the problems set forth above.
In one aspect of the present invention, a vehicle heat exchanger is provided, including a plurality of flat tubes communicating with an enclosed space defined by a plurality of connected closure pieces. The tubes have open ends secured to and extending through tube openings in one of the closure pieces. A first corner of the defined space is defined by the connected joint of three of the closure pieces where a first of the closure pieces has a first bent edge abutting an end of a second of the closure pieces adjacent a generally flat section of a third of the closure pieces. The first bent edge of the first closure piece adjacent the first corner comprises a bend in a thin portion of the first closure piece. The thin portion has a sheet thickness which is less than the sheet thickness of the adjacent portions of the first closure piece.
In one form of this aspect of the invention, the first bent edge comprises a flange at generally right angles to a wall member of the first closure piece which defines a side of the defined space, and the flange is generally aligned with the generally flat section of the third closure piece.
In another form of this aspect of the invention, the one closure piece includes four side flanges extending generally in the direction of the tubes, wherein at least two of the flanges join at the first bent edge.
In still another form of this aspect of the invention, four corners of the defined space are each defined by the connected joint of three of the closure pieces. In this form, the first closure piece includes four side flanges extending generally in the direction of the tubes and joined in a rectangular configuration with four bent edges at the joining of the side flanges. Each of the four corners is defined by a connected joint of three of the closure pieces, one of which is one of the bent edges of the first closure piece. Each of the bent edges comprise a bend in a thin portion of the first closure piece having a sheet thickness which is less than the sheet thickness of the adjacent portions of the first closure piece. In further forms, the first closure piece is a header, other closure pieces are closure caps and a tank closure, and two side flanges on opposite ends of the header are fluid tight sealed to the first and second closure caps, respectively, along their length, and the other two side flanges are fluid tight sealed to the tank closure along their length, and the tank closure and the side flanges are fluid tight sealed.
In still further forms, the first bent edge at the thin portion of the first closure piece has an outer bending radii of 0.8 mm or less, the one of the closure pieces is a header, the plurality of connected closure pieces comprise a manifold, and/or the closure pieces are aluminum with a fluid tight seal at the first corner formed by solder.
In another aspect of the present invention, a method is provided for manufacturing a vehicle heat exchanger having a plurality of flat tubes having open ends secured to a manifold defined by connected closure pieces, the closure pieces being connected whereby a first corner of the manifold is defined by the connected joint of three of the closure pieces. The method includes the steps of (1) forming a thin portion of a first of the closure pieces with a sheet thickness which is less than the sheet thickness of the adjacent portions of the first closure piece, (2) deforming the first closure piece thin portion to form a first bent edge, and (3) connecting the closure pieces to form the manifold, wherein the first bent edge abuts an end of a second of the closure pieces adjacent a generally flat section of a third of the closure pieces.
In a further form of this aspect of the invention, the closure pieces are aluminum, and the connecting step comprises soldering the aluminum pieces together.
In a still further form of this aspect of the invention, the forming step includes reducing the sheet thickness at the thin portion by about ⅓ over the sheet thickness of the adjacent portions.
In yet another form of this aspect of the invention, a plurality of corners are defined by the connected joint of three of the closure pieces and the method includes, for each of the plurality of corners, (1) in at least one of the closure pieces forming a thin portion in an area to be at the connected joint defining the corner, wherein the thin portion for each corner has a sheet thickness which is less than the sheet thickness of the adjacent portions of the at least one closure piece, and (2) deforming the closure piece thin portion to form a bent edge, where the connecting step includes connecting the closure pieces to form the manifold with at least one of the bent edges abutting an end of a second of the closure pieces adjacent a generally flat section of a third of the closure pieces at each of the plurality of corners.
The invention is described below in practical examples, for which purpose the accompanying figures are referred to. In the figures:
a and 10b are perspective views of still further headers which may be used with the present invention;
a and 14b are detailed cross-sectional views of a corner region of a manifold, showing representative alternate structures which may be used within the scope of the present invention; and
a, 15b, 15c, 15d and 15e show five representative alternate embodiments of side plates and closure caps which may be used within the scope of the present invention.
In the practical example of a heat exchanger 18 according to
The header 20 such as illustrated in
The header 20 is assembled as described in more detailed hereafter with other closure pieces to form a manifold 40 which defines an enclosed space such as is known for handling the flow of fluid from the tubes 24 such as is known in the art. It will be readily recognized that the details of the manifold 40, including specifically the provision of system inlets and outlets, may be designed according to the desired operation of the heat exchanger 18. The description herein is generally of the manifold 40 without reference to such inlets and outlets, which may be suitably provided according to design requirements.
As illustrated, the manifold 40 may be formed by suitable connection of the header 20, a generally U-shaped tank closure 42 having opposite side walls 44, 46, and closure caps 48 on opposite ends (only one cap 48 is shown in the cut off view of
The closure caps 48 may be, as illustrated in
The side plates 50 may have longitudinally extending flanges 56 along their length. Further, the closure caps 48 may have longitudinally extending flanges 60 on opposite sides, as well as an end flange 62 for suitable strong connection in forming the manifold 40 as described in more detail hereafter.
Specifically, the header 20 and side plates 50 with closure caps 48 may be cut from a solder-coated aluminum sheet in any suitable fashion. Once cut, they may further be subjected to metal working operations as described hereafter.
In the enlarged detail shown in
As best seen in
It should be further mentioned for the
Further, as shown particularly in
As illustrated in
Alternatively, as illustrated in
As a result, as shown in
The closure caps 92 (only one of which is shown in
a–10b illustrate still other embodiments of headers which may be advantageously used with the present invention. For example, header 100 in
With this structure, the closure cap 122 has a flange running around its entire periphery, allowing for excellent connections to the tank closure 42 and the header 120. It is unimportant whether the cap flange (60, 62, 124) is directed outward, as shown, or inward into the formed manifold 40′.
Moreover, it should be appreciated that the
a–14b show details, similar to
For example, in
It can be readily seen in
b similarly illustrates the provision of only one thin portion at the corner, and is essentially the same as the structure illustrated in
In short, it should be appreciated that the present invention incorporates a wide variety of structures containing thin portions enabling the bending radius of the closure piece at the described corners to be reduced so as to close the open cross section at such corners to allow use of advantageous solder methods to securely close the open cross section. Variations as to which bent edges may be formed as described herein may be selected dependent upon the individual case, that is, on how much solder is available in the corner region and whether the solder supply is sufficient to properly close the remaining gap.
a–e illustrate five different embodiments of integral side plates 150a–e and closure caps 152a–e which may be used with different heat exchangers and header constructions. Various portions of the closure caps may be thinned in accordance with the present invention to provide a small bend radius at desired corners such as indicated generally at 154a–e in each of the embodiments. As illustrated in the various embodiments, the closure caps 152a–e may be aligned with, or offset in or out, relative to the side plates 150a–e. Further, cut out portions may be provided in the side flanges of each. Still further, the integral structure may be configured so as to permit expansion under the influence of temperature fluctuations.
With an understanding of the above, it should be appreciated that manufacture of heat exchangers embodiments incorporating the present invention may be accomplished by suitably assembling closure pieces wherein, in at least one corner of the manifold defined by the connected joint of three closure pieces, (1) a thin portion of at least one closure piece is formed with a sheet thickness which is less than the sheet thickness of the adjacent portions, (2) the closure piece thin portion is deformed to form a first bent edge, and (3) the closure pieces are connected to form the manifold, wherein the formed bent edge abuts an end of a second of the closure pieces adjacent a generally flat section of a third of the closure pieces. The connecting step may be readily accomplished via suitable heading of solder coated aluminum sheets forming at least one of the closure pieces, where the solder is caused to bond the components and provide a fluid tight seal, including at the defined corner.
Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.
Number | Date | Country | Kind |
---|---|---|---|
102 37 769 | Aug 2002 | DE | national |
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1277282 | Sep 1968 | DE |
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Number | Date | Country | |
---|---|---|---|
20040069468 A1 | Apr 2004 | US |