JP2006513392A - Heat exchangers, especially gas coolers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a heat exchanger so that an assembly box has high strength at a light weight and can be manufactured at low cost.
A heat exchanger for a CO ₂ refrigerant circuit of an automobile air conditioner, in particular a gas cooler, is divided into two vertical passages (5, 6) by a vertical separation wall (7), and at least one collective box (2 ) And one row of flat tubes (3). The flat tube end (3a) of the flat tube is received in the hole (4) of the collecting box (2) and fluidly coupled to the longitudinal passages (5, 6). A collecting box (2) with longitudinal passages (5, 6) is provided with a longitudinal edge (9, 10) with tongues (11, 12) and a central coupling region (14) with recesses (13) Is bent from the belt strip (8), the vertical edges (9, 10) form the vertical separation wall (7) and are locked in the recess (13) via the tongues (11, 12) Has been.

Description

The present invention relates to a heat exchanger for a CO ₂ refrigerant circuit of an automobile air conditioner, in particular a gas cooler, in which at least one collection box partitioned into two vertical passages by a vertical separation wall, a row of flat tubes, And the flat tube end of the flat tube is received in the hole of the collecting box and fluidly coupled to the longitudinal passage.

A heat exchanger for an air conditioner using R134a as a refrigerant, for example, a condenser, includes a heat exchanger network including flat tubes, and a circular or other cross-sectional header disposed on both sides of the network. Another heat exchanger for an air conditioner, for example a two-row evaporator according to the Applicant's patent document 1, has a collection box divided into two vertical chambers, the collection box from the prepared substrate to the edge of the substrate. Manufactured by folding the area. In this way, a central double-layer vertical separation wall is obtained, and this vertical separation wall is fixed in a recess at the bottom of the flat collection box by a tongue piece. Two rows of tube holders for both flat tube rows are arranged at the bottom. That is, each vertical chamber communicates with one flat tube row. This structure style already achieves a relatively high pressure resistance. However, modern air conditioners that use CO ₂ (R744) as a refrigerant produce fairly high pressures, which can reach about 10 times and can no longer be overcome with conventional heat exchanger design. For this reason, US Pat. No. 6,057,056 proposes an extruded header with increased wall thickness, which consists of four juxtaposed circular flow passages. The manufacture of such an extruded header is expensive because it requires tools.

Another type of header has been proposed in US Pat. No. 6,057,056, which consists of two or three extruded or pressure formed members and has two circular flow passages for refrigerant (CO ₂ ). Even in this construction mode, at least one member of the header must be produced by extrusion or other laborious plastic working methods, which negatively affects the production costs of heat exchangers such as gas coolers.
German Patent Application Publication No. 19826881 International Publication No. 98/51983 German Patent Application Publication No. 199090689

  The object of the present invention is therefore to improve the heat exchanger of the type indicated at the beginning so that the assembly box has a high strength at a light weight and can be manufactured at low cost.

  The problem is that the collection box with the vertical passage is folded from a strip prepared with a vertical edge with tongue and a central coupling region with a recess, the vertical edge forms a vertical separation wall, And it is solved by being locked in the recess through the tongue.

BEST MODE FOR CARRYING OUT THE INVENTION

  As is known per se from the state of the art pointed out at the beginning (Patent Document 1), the collecting box is composed of a single part and is bent from one strip so as to produce two longitudinal passages, however. The longitudinal passage-unlike the current state of the art-is fluidly coupled to only one flat tube row. This construction style of the collecting box allows a substantially circular cross section and thus a more pressure-resistant collecting box. The double-layer longitudinal separation wall is fixed and locked in the central region of the strip by means of a tongue piece, which facilitates manufacture and increases strength.

  According to one advantageous configuration of the invention, the tongue piece can be arranged either on the side facing the flat tube or on the opposite side of the flat tube in order to fix the longitudinal separation wall. This increases the possibility of modeling heat exchangers.

  According to one advantageous configuration of the invention, notches are arranged in the longitudinal separating wall in the region of the flat tube end projecting into the longitudinal passage, and the flat tube end engages in these notches. This allows the flat tube to be pushed into the collection box considerably-almost to the center-and configured at the maximum depth (the flat tube depth is measured in the direction of air flow). Therefore, the collecting box is not deeper than the flat tube. This advantageously provides a space for the working part or the tube holding part.

  In another advantageous configuration of the invention, a gap is left between the notch and the end of the flat tube, the gap being configured, for example, in a U shape, or simply arranged laterally or above the flat tube. Can be kept. In that case, it is advantageous if the notch portion simultaneously serves as a stopper for the flat tube when the flat tube is inserted into the grooved hole of the collecting box. This provides accurate positioning for the flat tube within the collection box. A gap provides pressure and flow compensation between both adjacent longitudinal passages.

  According to another advantageous configuration of the invention, the collecting box area in which the recesses with tongues are arranged can be drawn inwardly, i.e. in the direction of the longitudinal separating wall, whereby the crossing of the collecting box A certain “tailoring” is obtained with respect to the surface. It is thus achieved that the cross section of the longitudinal channel approximates a circular cross section even further, i.e. beyond the circumference of 270 degrees, which is advantageous for strength and weight.

  Finally, it may be advantageous to configure the cross sections of both longitudinal passages to be different rather than identical, whereby the position of the separating wall can also be eccentric, i.e. asymmetric. What is important during the formation of the assembly box is that the tongue piece is arranged substantially perpendicularly to the connecting band having the recesses to achieve the optimum bar effect.

  Embodiments of the invention are shown in the drawings and are described in detail below.

A gas cooler 1 partially shown in FIG. 1 has a collection box 2 and a flat tube 3, and the flat tube has a flat tube end 3 a leading to the collection box 2 and is received in the grooved hole 4. Between the flat tubes 3 —not shown—corrugated fins are arranged to increase the air side heat transfer area. The gas cooler 1 is particularly suitable for use in an automotive air conditioner refrigerant circuit using CO ₂ as a refrigerant, however, it is not limited to this application. Gas cooler at the primary side, i.e. the gaseous CO ₂ is circulated at a pressure of about 120 bar in a collection box and a flat tube, it is added to the ambient air in the secondary side. The role of the gas cooler is to cool the CO ₂ gas from a temperature of about 150 ° C. to 50 ° C. The pressure appearing at that time is about 10 times that of the conventional condenser in the circuit having the refrigerant R134a.

  FIG. 2 shows the gas cooler 1 according to FIG. 1 in section, and it is clear that the collecting box 2 is composed of a single member. The collecting box has two vertical chambers 5 and 6, which are separated from each other by a double vertical separation wall 7. The assembly box 2 is manufactured from a substrate or strip 8 which has outer edge bands or vertical edges 9, 10, which have tongues 11, 12. A concave portion 13 is arranged in the center of the band plate 8 in accordance with the arrangement of the tongue pieces 11 and 12.

  From the strip 8, which has been prepared, i.e. cut and punched out, the side with the longitudinal edges 9, 10 is bent into a substantially cylindrical passage 5, 6 so that the longitudinal edges 9, 10 are central and substantially perpendicular to the central coupling region. The assembly box 2 is manufactured so that it is pulled back to 14 where it is inserted into the recess 13 by the tongues 11,12. Thus, the vertical edges 9 and 10 are fixed, and the assembly box 2 is finished for the brazing process. The flat tube 3 has its flat tube end 3 a inserted into the hole 4, and its upper ridge 3 b protrudes into the free cross section of the longitudinal passages 5, 6 by almost half. Since the cross section of the longitudinal passages 5, 6 has its maximum width here, a stop for the flat tube 3 is obtained by the cross section narrowing thereafter.

  FIG. 3 shows a cross section of the gas cooler 1 in the III-III plane of FIG. The separating wall 7 shown by this section of the longitudinal passage 5 has a U-shaped notch 15 in the region of the flat tube end 3a. A gap 16 is left between the contour of the flat tube end 3 a and the contour of the notch 15, and this clearance opens the flow cross section between both longitudinal passages 5, 6. On the one hand, the refrigerant can flow out from the center of the flat tube end 3a through the gap 16, and on the other hand, the refrigerant can flow from one longitudinal passage 5 to the other longitudinal passage 6 and vice versa, between the two longitudinal passages. Pressure compensation can be performed. The notch 15 or gap shape 16 is only illustrated in the drawing-the gap shape is only above the flat tube end, i.e. only above the upper ridge 3b or next to the flat tube end 3a. It can also be changed so that there is only a gap. In the last case, the upper ridge 3b of the flat tube will come into contact with the notch of the separating wall 7 and this will provide a stop. The tongue pieces 11 and 12 protrude from the outer wall of the assembly box 2 and are respectively arranged at substantially the center between the two flat tubes 3. However, it is also possible to jump over the distance of one or a plurality of flat tubes and arrange the tongue pieces 11, 12 and the recess 13 between the two flat tubes at an arbitrary distance.

  The gas cooler 20 of another embodiment shown in FIG. 4 includes a collection box 21 and a flat tube 22. Here, the tongue piece 23 and the recess 24 are arranged on the upper surface of the assembly box 21, that is, on the side opposite to the flat tube 22.

  FIG. 5 shows the gas cooler 20 in section. The collecting box 21 is basically the same as in the embodiment according to FIG. The collecting box 21 has two vertical chambers 21 a and 21 b, and the vertical chambers are separated from each other by a double vertical separation wall 25. The flat tube 22 is pushed into the assembly box 21 through a hole which cannot be seen here, and the flat tube end 22a closes almost half of the longitudinal passages 21a and 21b. Accordingly, the upper ridge 22b is at the height of the maximum width of the internal cross section. The flat tube 22 has a continuous depth t extending into the assembly box 21.

  6 is a cross-sectional view of the longitudinal passage 21a in the VI-VI plane of FIG. The flat tube 22 is fitted through a corresponding hole 26 in the assembly box 21, and the hole 26 extends over the entire depth t of the flat tube 22. A substantially circular notch 27 is disposed above the upper ridge 22b of the flat tube end 22a, and the notch moves to a rectangular cross section in accordance with the flat tube cross section, thus introducing the flat tube end 22a. enable. A substantially circular gap 28 is left above the upper ridge 22b of the flat tube end 22a, and this gap forms a flow cross section between the two vertical chambers 21a, 21b. No gap is left immediately next to the flat tube end 22a. The tongues 23 and the recesses which are likewise not visible here are again arranged between the flat tubes 22 respectively.

  FIG. 7 shows a third embodiment of the gas cooler 30 including the collecting box 31 and the flat tube 32. The double vertical separating wall 33 is locked in the central coupling area 35 by means of a tongue piece 34, this coupling area 35 being drawn inward somewhat, ie against the lower boundary line l of the collecting box 31. Is shifted inward by the value x. Thereby, the cross section of the vertical passages 36 and 37 is approximated to a circular shape exceeding a three-quarter circle (270 degrees). Nevertheless, the step-like central coupling region 35 and the double vertical separation wall 33 form a right angle. Therefore, this cross-sectional shape provides higher pressure resistance for the collective box 31.

All the embodiments described above are suitable and advantageous for high internal pressures, and therefore also for refrigerant circuits operating on CO ₂ in automotive air conditioners.

It is a fragmentary perspective view of a gas cooler. FIG. 2 is a cross-sectional view of the gas cooler according to FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. 2 shows a second embodiment of the gas cooler. FIG. 5 is a sectional view of the gas cooler according to FIG. 4. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. A third embodiment of a gas cooler is shown in cross section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas cooler 2 Collecting box 3 Flat tube 4 Hole 5 Vertical passage 6 Vertical chamber 7 Vertical separation wall 8 Strip plate 9 Vertical edge 10 Vertical edge 11 Tongue piece 12 Tongue piece 13 Recessed part 14 Central coupling area 15 U-shaped notch 16 Gap 17 Gap 20 Gas cooler 21 Collecting box 21a Vertical chamber 21b Vertical chamber 22 Flat tube 23 Tongue piece 24 Recess 25 Vertical separation wall 26 Hole 27 Notch 28 Gap 30 Gas cooler 31 Collecting box 32 Flat tube 33 Vertical separation wall 34 Tongue piece 35 Central coupling area 36 Vertical passage 37 Vertical passage 38 Crevice

Claims (14)

A heat exchanger for a CO ₂ refrigerant circuit of an automobile air conditioner, in particular a gas cooler, and at least one collecting box (2) partitioned into two vertical passages (5, 6) by a vertical separation wall (7); The flat tube end (3a) is received in the hole (4) of the collecting box (2) and fluidly coupled to the longitudinal passages (5, 6). The assembly box (2) with the longitudinal passages (5, 6) comprises a longitudinal edge (9, 10) with tongues (11, 12) and a central coupling region (14) with recesses (13). Folded from the prepared strip (8), the vertical edges (9, 10) form a vertical separation wall (7), and inside the recess (13) via the tongues (11, 12) The heat exchanger is characterized by being locked by.   2. A heat exchanger according to claim 1, characterized in that the tongue pieces (11, 12) and the recesses (13) are arranged on the side of the collecting box (2) facing the flat tube (3).   The heat exchanger according to claim 1, characterized in that the tongue piece (23) and the recess (24) are arranged on the opposite side of the flat tube (22) of the collecting box (21).   The longitudinal separation wall (7, 25) has notches (15, 27), and the flat tube ends (3a, 22a) are engaged in these notches. Or the heat exchanger of 3.   A heat exchanger according to any one of the preceding claims, characterized in that the collecting box or the collecting box part is provided with corresponding deformations, moldings and / or protrusions which serve as pipe stops.   6. A heat exchanger according to claim 4 or 5, characterized in that a gap (16, 28) is left between the notch (15, 27) and the flat tube end (3a, 22a).   7. A heat exchanger according to claim 6, characterized in that the gap (16) is U-shaped.   7. A heat exchanger according to claim 6, characterized in that the gap is arranged laterally and the notch forms a tube end stop.   7. A heat exchanger according to claim 6, characterized in that the gap (28) is arranged above and / or below the flat tube ends (22a, 22b).   The tongues (11, 12; 23) and the recesses (13, 24) are arranged between the nth flat tubes (3, 22), and n = 1, 2, 3, 4, 5,. The heat exchanger according to any one of claims 1 to 9, characterized in that   11. The longitudinal passage (5, 6; 23, 24; 36, 37) has a substantially circular cross-section, in particular over a circumferential range of at least 270 degrees. The heat exchanger according to item 1.   12. Heat exchange according to claim 11, characterized in that the central coupling region (35) for receiving the tongue (34) is drawn in by the value x in the direction of the longitudinal separating wall (33) or curved outwards. vessel.   A heat exchanger according to any one of the preceding claims, characterized in that the cross sections of the longitudinal passages differ in shape and / or size. A heat exchanger according to any one of the preceding claims, characterized in that the longitudinal separation wall has at least one hole or notch or overflow hole.

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