Heat exchange – Tubular structure
Reexamination Certificate
2001-08-21
2003-12-23
Flanigan, Allen (Department: 3743)
Heat exchange
Tubular structure
C029S890053
Reexamination Certificate
active
06666265
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a heat exchanger to be used for a refrigerating cycle mounted on a vehicle or the like, a method of manufacturing the heat exchanger and a method of manufacturing a tube for heat exchange.
BACKGROUND ART
Conventionally, the heat exchangers to be used for the refrigerating cycle of vehicles and others are comprised of stacking a plurality of flat tubes, mounting fins between the stacked tubes, and connecting either end of the tubes to tanks. A heat exchange medium flowing from another apparatus of the refrigerating cycle into the tanks is distributed to the respective tubes to make heat exchange with outside air through the tubes and fins.
Generally, the tubes used for the heat exchangers are formed into a flat cross-sectional shape by joining the ends of one or two plates. Forming to have the flat cross-sectional shape is to enlarge a contact area between the fin and the tube so to efficiently conduct heat of the medium from the heat exchange tubes to the fins, thereby improving heat exchange performance.
For example, as shown in
FIG. 11
, a flat tube
2
is formed by bending a single plate at about its center to form a U-shaped cross section so to form beads or the like, and brazing to mutually adhere the opposed surfaces of both ends
2
h
,
2
h
of the plate.
The tubes
2
formed to have the flat cross-sectional shape are fitted with fins and alternately stacked to form a core, the both ends of the tubes
2
are fitted to tanks and brazed to form a heat exchanger
1
.
But, the tube
2
having the opposed surfaces of the both ends
2
h
,
2
h
of the plate contacted with each other had a possibility that the portions, where the both ends
2
h
,
2
h
are joined, would open before or at brazing to degrade the assembling property of the tubes
2
and the tanks or to cause defective brazing.
And, when the tube
2
was formed by joining the both ends
2
h
,
2
h
of the plate, the joint portion had a shape protruded from the other portion of the tube, so that there was a possibility of causing defective brazing because tube insertion holes of the tanks into which the tubes were inserted became complex and a gap was formed between the tube fitted to the tube insertion hole and the tube insertion hole.
In addition, a heat exchange tube
40
described in Japanese Patent Application Laid-Open Publication No. Hei 10-274489 has fold-back portions
41
,
41
which are formed by bending to fold back the ends of two plates which configure a tube, and which are mutually joined on the fold-back outer surfaces as shown in FIG.
12
.
The heat exchange tube
50
described in Japanese Patent Application Laid-Open Publication No. Hei 11-248383 forms fold-back portions
51
a
,
51
b
at the ends of two plates, caulking the fold-back portions
51
a
,
51
b
after joining them mutually, and brazing the caulked portion as shown in FIG.
13
.
But, the aforesaid tube
40
is formed to have a gap
42
a
in a triangle cross-sectional shape at the joint portion
42
where the fold-back portions
41
,
41
are joined.
The tube
50
is also formed a gap
52
a
having a triangle cross-sectional shape in a joint portion
52
where the fold-back portions
51
a
,
51
a
are joined.
These gaps
42
a
,
52
a
having a triangle cross-sectional shape are not supplied with a sufficient amount of flux or a brazing material, resulting in the possibility of causing defective brazing.
When usual sizing is performed, the ends of the plates are rolled in a direction of the insides of the tubes
40
,
50
, and there is a disadvantage that the gaps
42
a
,
52
a
having a triangle cross-sectional shape are not filled with extra thickness of the plates.
And, a heat exchanger using the aforesaid tubes, such as a condenser, is generally mounted at the front or a lower part of a vehicle.
Therefore, a small stone or the like having entered from the outside into the vehicle tends to hit the front of the condenser and becomes a cause of breaking the tubes to leak a medium or the like, resulting in a problem that the air conditioner does not work.
Accordingly, it is an object of the present invention to improve an assembling property and a brazing property by preventing the joint portion of the tube from opening and modifying the peripheral shape of the tube, and to provide a heat exchanger using tubes resistant to stone hitting or the like, a method of manufacturing the heat exchanger and a method of manufacturing the tubes for the heat exchange.
SUMMARY OF THE INVENTION
The invention described in claim
1
is a heat exchanger comprising a core which is consisting of tubes provided with medium passages and fins fitted to the tubes, and tanks to which ends of the tubes are connected, wherein the tube is formed to have a flat cross-sectional shape by joining ends of one or two plates, the tube has a contact portion which is formed by bending at least one of the plate ends a plurality of times and overlaying the plate end on the other plate end, and a joint portion which is formed by placing a part of the contact portion on the top or bottom flat surface of the tube and mutually engaging the both ends of the plate.
For example, when a pressure is applied in directions of the top and bottom flat surfaces of the tube, an extra thickness at the end of each plate configuring the tube escapes in the direction of the mutually engaged contact portions, and the gaps in the contact portions are filled.
Therefore, the peripheries of the tube are restricted to within the tolerance of a predetermined dimension.
Thus, the tubes are improved in the assembling property with the tanks, and the gaps in the contact portions of the tubes are eliminated, so that adhesion between the tube insertion holes of the tanks and the peripheries of the tubes is improved, and the brazing property can be improved.
The invention described in claim
2
is the invention according to claim
1
, wherein the tube is provided with a joint portion which is formed by fully covering the end of the tube with one of the plate ends and mutually engaging the both plate ends.
Here, the end of the tube means at least one of the ends of the tube.
For example, when sizing is performed to apply a pressure in the top and bottom flat surface directions of the tube, the extra thickness of the plate end produced by the application of pressure escape in a direction intersecting at right angles with the direction that the pressure is applied, so that the gap between the mutually engaged contact portions is filled with the extra thickness.
Therefore, the tube is restricted its periphery to within the tolerance of a predetermined size.
Thus, because the tube's assembling property with the tanks is improved and no gap is caused between the contact portions of the tubes, adhesion between the tube insertion holes of the tanks and the tube periphery is improved, and the tube can be improved its brazing property.
The invention described in claim
3
is a heat exchanger comprising a core which is consisting of tubes provided with medium passages and fins fitted to the tubes, and tanks to which ends of the tubes are connected, wherein the tube is provided with a joint portion which is formed by contacting at least one plate end surface to the other plate end, and the joint portion is such that one plate end surface is engaged with the other plate end brazed to prevent the tubes from opening.
When the tubes are prevented from opening, the assembling property of the tubes and the tanks becomes good. And, because the tubes are prevented from opening, the brazing property between the tubes and the tanks is improved, and it becomes possible to provide a quality heat exchanger free from a leakage of the medium or the like.
The invention described in claim
4
is the heat exchanger according to any of claims
1
to
3
, wherein the joint portion of the tube uses a tube in which a portion positioned on at least the periphery of the tube is present in the same peripheral surface as the outer peripheral surface of the tube configuring the medium passa
Akaike Jun
Akiyama Shoji
Kato Soichi
Kurihara Shin
Ochiai Kazuo
Flanigan Allen
Kanesaka & Takeuchi
Zexel Valeo Climate Control Corporation
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