U.S. patent application number 10/572482 was filed with the patent office on 2007-01-04 for heat exchanger.
This patent application is currently assigned to BEHR GmbH & CO. KG. Invention is credited to Karsten Emrich, Werner Helms, Markus Reck, Stefan Weise.
Application Number | 20070000657 10/572482 |
Document ID | / |
Family ID | 34305890 |
Filed Date | 2007-01-04 |
United States Patent
Application |
20070000657 |
Kind Code |
A1 |
Emrich; Karsten ; et
al. |
January 4, 2007 |
Heat exchanger
Abstract
Disclosed is a heat exchanger comprising pipes and at least one
receptacle (20). Said receptacle encompasses at least one pipe
bottom (30) that is provided with passages (70), said passages (70)
being surrounded by flanks (91-94).
Inventors: |
Emrich; Karsten; (Stuttgart,
DE) ; Helms; Werner; (Esslingen, DE) ; Reck;
Markus; (Stuttgart, DE) ; Weise; Stefan;
(Stuttgart, DE) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
BEHR GmbH & CO. KG
|
Family ID: |
34305890 |
Appl. No.: |
10/572482 |
Filed: |
September 9, 2004 |
PCT Filed: |
September 9, 2004 |
PCT NO: |
PCT/EP04/10069 |
371 Date: |
March 17, 2006 |
Current U.S.
Class: |
165/173 |
Current CPC
Class: |
F28D 2021/0082 20130101;
B21D 39/06 20130101; F28F 9/182 20130101; F28F 2225/08 20130101;
F28D 1/0535 20130101; F28F 9/02 20130101 |
Class at
Publication: |
165/173 |
International
Class: |
F28F 9/02 20060101
F28F009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 17, 2003 |
DE |
103 43 239.6 |
Claims
1. A heat exchanger having tubes and at least one header box, the
header box comprising at least one tube plate, the tube plate
having rims into which the tubes can be fitted, wherein the rims
are enclosed by a respective peripheral flank, the flanks of two
adjacent rims bordering each other with a bead being formed.
2. The heat exchanger as claimed in claim 1, wherein the flanks
each have an essentially constant width over the circumference of a
rim.
3. The heat exchanger as claimed in claim 1, wherein the tubes are
flat tubes arranged in at least one row, in that the rims are of
elongate design corresponding to the tube cross sections, and in
that the flanks of the rims border one another with elongate beads
being formed.
4. The heat exchanger as claimed in claim 1, wherein the flanks
each have a rounded portion with an approximately constant radius
of curvature.
5. The heat exchanger as claimed in claim 4, wherein the flanks
each have a plurality of rounded portions with different radii of
curvature.
6. The heat exchanger as claimed in claim 1, wherein the flanks
each have at least one planar region.
7. The heat exchanger as claimed in claim 6, the at least one
planar region forms an obtuse angle, in particular an angle of
between 30.degree. and 60.degree., with the respective rim.
8. The heat exchanger as claimed in claim 1, wherein the rims face
out of the at least one header box.
9. A charge-air cooler, in particular for a motor vehicle,
characterized by the features of claim 1.
10. A method for producing a tube plate, comprising: a) providing a
planar metal sheet, b) raising one or more edge regions of the
planar metal sheet by means of a forming process, c) placing
depressions, which border one another, into the metal sheet by
means of a forming process, the depressions each having an
essentially planar base surface and a flank enclosing and
encircling the base surface, d) piercing the base surfaces by means
of a draw-through process and, in particular, and e) impressing
introductory slopes therein in order to facilitate an introduction
of tubes into the rims produced in step d).
Description
[0001] The present invention relates to a heat exchanger, in
particular a charge-air cooler for a motor vehicle.
[0002] In order to increase the power of an internal combustion
engine, it is possible for the air which is to be fed for
combustion to be compressed, for example using a turbocharger,
before it is fed to the combustion chambers of the internal
combustion engine. However, compressing the air at the same time
also heats it, which is disadvantageous for an optimum sequence of
the combustion process. By way of example, this can cause premature
ignition or increased emissions of nitrogen oxide. To avoid the
disadvantageous consequences of combustion of superheated air
supplied, a heat exchanger designed as a charge-air cooler, which
can be used to cool the compressed air to an acceptable temperature
before its combustion, is connected downstream of a
turbocharger.
[0003] A charge-air cooler is described, for example, in DE 197 57
034 A1. In the heat exchanger disclosed therein, the hot air is
introduced into a first header passage of the heat exchanger, where
it is distributed and flows into flat tubes which open out into the
header passage. The flat tubes are arranged next to one another and
with the side faces which include the long sides of their cross
section parallel to one another, forming a flow path through which
cooling air is routed. Cooling fins, which are responsible for
effective heat exchange between the flat tubes and the cooling air
stream, are arranged between the flat tubes in the flow path. After
the cooling air stream has passed through, the flat tubes open out
into a second header passage, which feeds the cooled, compressed
charge air flowing into it for combustion in the engine.
[0004] In heat exchangers, such as in particular charge-air coolers
of this type, the tubes are usually fitted into openings in a tube
plate and are soldered in place in a fluid-tight manner. Each time
that compressed air is applied, this soldered join is subject to
high mechanical loads on account of rapid pressure changes. In
particular the narrow sides of flat tubes do not satisfy the
increasing demands on strength, which can result in leaks in
particular in regions of tube-plate joins of this type which face
the sides of the tube plate.
[0005] A simple way of increasing the strength of tube-plate joins
is to use tubes and/or tube plates with a greater wall thickness or
external and/or internal fins with a greater material thickness.
The increased mechanical stability is useful in both cases, but the
increased outlay that is required on material costs and weight is
very high.
[0006] Other proposed solutions deal with a reduction in the
mechanical loading on the tube-plate joins by the use of tie rods
in the charge-air boxes. These tie rods stabilize the charge-air
boxes and thereby relieve the load on the tube-plate joins, but
also increase the outlay on material and the pressure loss caused
by the charge-air cooler.
[0007] The object of the invention is to provide a heat exchanger,
in particular a charge-air cooler, in which mechanical loads on
tube-plate joins are reduced without an increased outlay on
material.
[0008] This object is achieved by a heat exchanger having the
features of claim 1.
[0009] According to claim 1, a heat exchanger has tubes which are
suitable to have a first medium flowing through them and a second
medium flowing around them, so that heat can be transferred from
the first medium to the second medium or vice versa. At least one
header box which is in communication with the tubes comprises at
least one tube plate, the tube plate being of essentially flat
design and having rims into which the tubes can be fitted in order
to form the communicating connection to the header box.
[0010] The basic concept of the invention is to geometrically
configure those regions of the tube plate which surround the rims
in the form of depressions or elevations in such a manner that the
rims are in each case arranged on the "base" of a depression or on
the "summit" of an elevation. As a result of this, the rims are
enclosed peripherally by flanks, namely the flanks of the
depressions or elevations. A geometrical configuration of this
type, particularly the peripheral configuration of the flanks,
increases the flexural rigidity of the tube plate in a plurality of
directions in comparison to a flat tube plate, thus reducing
deformations that occur due to a compressive load on the header
box, as a result of which joins of tubes to the tube plate are
mechanically relieved of load. The depressions or elevations are
preferably of such a width that the flanks of in each case two
adjacent rims border each other with a reinforcing bead being
formed.
[0011] The configuration of the heat exchanger according to the
invention increases its mechanical strength and therefore also its
service life without requiring an increased outlay on material or
number of parts.
[0012] Advantageous embodiments of the invention are the subject
matter of the subclaims.
[0013] According to a preferred embodiment, the flanks each have an
essentially constant width over the circumference of a rim. This
essentially uniformly increases the flexural rigidity of the tube
plate in all directions.
[0014] According to an advantageous embodiment, the tubes are
designed as flat tubes and are arranged in one or more rows. The
rims and the beads which are situated in between and are formed by
the flanks are then of elongate design corresponding to the tube
cross sections.
[0015] The flanks preferably each have a rounded portion with an
approximately constant radius of curvature or a plurality of
rounded portions with different radii of curvature. This achieves a
particularly good approximation to a semicircular cross section of
the beads situated between the rims, thus resulting in particularly
high flexural rigidity.
[0016] According to another embodiment, the flanks each comprise
one or more planar regions, so that the flanks or the beads have a
faceted form between the rims. This allows reliable production with
low manufacturing tolerances.
[0017] The at least one planar region particularly preferably forms
an obtuse angle with the respective rim. This means that the rim
itself brings about an additional increase in the flexural rigidity
of the tube plate, since the rim faces in the same direction as the
depression or elevation on the "base" of which or on the "summit"
of which the rim is situated.
[0018] The angle between the planar region of the flank and the rim
is preferably between 300 and 600, particularly preferably
approximately 45.degree.. In this case, a width of the flank is,
under some circumstances, approximately equal to a height of the
flank, thus resulting in particularly high stability of the tube
plate to deformations.
[0019] According to an advantageous configuration, the rims face
out of the at least one header box. This has, if appropriate, the
advantage that in each case one region of the flanks, which region
is adjacent to an edge of the tube plate, merges into an edge of
the tube plate, which edge is raised under some circumstances, thus
resulting in a further increase in strength of the tube plate.
[0020] According to a preferred development, the heat exchanger
according to the invention is designed as a charge-air cooler which
can particularly preferably be used in motor vehicles. In
particular, the charge-air cooler has two header boxes, a first of
which is provided to distribute charge air and a second of which is
provided to collect charge air. It is advantageous for each of the
header boxes to have precisely one tube plate, which is provided
with a row of tube openings. It is also advantageous to use a row
of flat tubes with in particular soldered corrugated fins between
them, since this increases the heat-transfer surface area. The
cooling medium used is preferably air, although other cooling
media, such as water or coolant, are also conceivable.
[0021] According to an advantageous embodiment of the invention, a
tube plate is produced by one or more edge regions of a planar
metal sheet being raised by means of a forming process and
depressions, which border one another, being placed into the metal
sheet. In this case, the depressions each have an essentially
planar base surface and a flank enclosing and encircling the base
surface. Subsequently, the base surfaces of the depressions are
pierced with the aid of a draw-through process with rims being
formed. If tubes are to be fitted into the tube plate from the side
of the depressions, it is particularly preferable for introductory
slopes to be impressed therein in order to facilitate a fitting of
tubes in this way into the rims.
[0022] An embodiment of a tube plate with one or more rows of
identical flanks and/or rims is advantageous in terms of
manufacturing.
[0023] The invention is explained below on the basis of exemplary
embodiments and with reference to the drawings, in which
[0024] FIG. 1 shows an oblique view of a tube plate,
[0025] FIG. 2 shows a side view of a tube plate with a tube
inserted,
[0026] FIG. 3 shows a longitudinal section through a tube plate
with tubes inserted,
[0027] FIG. 4 shows a longitudinal section through an excerpt of a
tube plate with a tube inserted, and
[0028] FIG. 5 shows a longitudinal section through an excerpt of a
tube plate with a tube inserted.
[0029] FIG. 1 shows an excerpt from a heat exchanger 10 in the form
of a perspective illustration. A header box 20 for distributing a
first medium comprises a tube plate 30 and a box cover (not shown),
which are welded to each other at a common contact surface 50. In
this case, the box cover is fitted into the tube plate 30. However,
it is also conceivable for the box cover to be fitted onto the tube
plate 30 or attached to the tube plate 30 in some other way. In
other exemplary embodiments (not shown), a tube plate and a box
cover are joined to one another by soldering, adhesive bonding or a
positive lock or are formed as a single part or integrally with one
another, i.e., for example from a deformed plate.
[0030] The tube plate 30 has a tube opening 60, the edge 70 of
which is deformed out of the header box as what is described as a
rim. An essentially rectangular flat tube can be fitted into the
tube opening 60 and can be soldered or welded to the tube plate 30.
Corrugated fins which adjoin the flat tube (not shown) on both
sides and are soldered to said flat tube, so that heat transfer
from a medium flowing through the tube to a medium flowing around
the tube and the fins or vice versa is increased, are not shown. In
total, the heat exchanger 10 comprises an entire row of alternating
flat tubes and corrugated fins, which form what is known as a
tube-fin block.
[0031] If the header box 20 is acted upon by a medium under
pressure, the header box 20 is under certain circumstances deformed
in such a manner that its cross-sectional shape approximates a
circular shape. To oppose a deformation of this type, the rim 70 is
enclosed by an encircling flank 90 which adjoins the rim at an
obtuse angle. The flank has a width which is essentially constant
all the way around the rim 70. This results in a uniform stiffening
of the tube plate 30 both in the longitudinal direction of the tube
plate, by means of the flank regions 91, 92 on the end sides of the
rim 70, and also in the transverse direction of the tube plate, by
means of the flank regions 93, 94 on the longitudinal sides of the
rim 70.
[0032] This results in reduced deformation of the tube plate 30
when the header box 20 is under compressive load. This reduced
deformation of the tube plate 30 involves a reduction in the
mechanical load on the tube or on the tube-plate join. In
particular, the end sides of the flat tube, which in mechanical
terms are under the highest loads in the event of such
pressure-induced deformations, are relieved of load as a
result.
[0033] As can be seen in the side view of the heat exchanger 110 in
FIG. 2, the tube 120 is fitted into the tube opening 160
sufficiently far for an upper edge region 121 of the tube 120 to
project beyond the tube plate 130. This ensures good utilization of
an inner surface (not visible), which faces the tube 120, of the
rim 170 as a bearing surface for a tube-plate join. This serves,
for example, to ensure sealed soldering. To avoid an unnecessarily
high pressure drop of the first medium across the heat exchanger,
the extent to which the tube 120 projects above the tube plate 130
is to be minimized. For this reason, the tube opening 160 is
situated in an essentially planar central region 131 of the tube
plate 130. The rim 170 is enclosed by a flank 190, the end sides
191, 192 of which, firstly, merge into the rim 170 at an obtuse
angle and, secondly, likewise at an obtuse angle, merge into a
raised edge region 132 of the tube plate 130. An additional
reduction in load on the tube 120 and/or the tube-plate join is
brought about on account of the associated S-shaped cross section
of the tube plate 130 in the region of the cover connection surface
150--edge region 132--flank region 191/192--rim 170.
[0034] FIG. 3 shows a further exemplary embodiment of part of a
heat exchanger 210 in a longitudinal section. Tubes 220, 221, 222
are fitted in rims 270, 271, 272 of a tube plate 230. In order to
reduce a drop in pressure across the heat exchanger 210 of a medium
flowing through the heat exchanger 210 and, inter alia, through the
tubes 220, 221, 222, the rims 270, 271, 272 face out of the header
box (otherwise not shown) and the tubes 220, 221, 222 do not
protrude over the tube plate 230 or the rims 270, 271, 272
thereof.
[0035] The rims 270, 271, 272 are enclosed here by flanks 290 which
each have a planar subregion 295. The planar subregion 295 encloses
an obtuse angle with the rim 270, as a result of which the
reinforcing effect of the depression, which is formed by the flank
290, in the tube plate 230 is additionally increased. The flanks
290 are directly adjacent to one another here, so that beads 299
are formed, which can be seen in cross section in FIG. 3. As is
clearly shown in this cross section, the beads 299 do not have any
horizontal regions situated between the flanks 290.
[0036] The width b is advantageously similar to the height h of the
flanks 290, particularly preferably is approximately the same. For
this reason, the angle between the planar subregion 295 of the
flank 290 and the rim 270 is approximately 45.degree.. For the
beads 299, this results in a bead angle .alpha. of approximately
90.degree., which is associated with a particularly high stiffening
effect of the beads 299.
[0037] FIG. 4 shows the excerpt of a modified configuration of the
heat exchanger from FIG. 3. The tube 320 protrudes here over the
rim 370, but ends below a surface 335 of the tube plate 330. This
results in increased manufacturing reliability with regard to a
fluid-tight connection between the tube plate 330 and the tube 320.
For example, a soldered join is improved by a soldering gap 376 to
be additionally added to the soldering gap 375. The soldering gap
serves here at the same time as an introductory slope for
facilitating the fitting of the tube 320 into the tube plate
330.
[0038] In contrast thereto, in the exemplary embodiment illustrated
in FIG. 5, the tube 420 protrudes beyond the rim 470 and beyond a
surface 435 of the tube plate 430. Owing to the associated,
relatively large tolerances with respect to the length of the tube
420, a further increase in the manufacturing reliability
results.
* * * * *