Heat exchanger

Abstract: In order to provide a heat exchanger with which it is possible to set a plurality of variations in the length of the tube elements (1) and that can be manufactured with relative ease and at low cost, the present invention is a heat exchanger in which a heat exchanger core (3) is constituted by laminating a plurality of tube elements (1) in each of which, the shape of the tube cross section from an intake/outlet portion, which is constituted with intake/outlet ports, to the vicinity of a flow path U-turn area, is consistent. The heat exchanger is assembled with the intake/outlet portion of each tube element of the heat exchanger core inserted into a separately provided tank. A partitioning plate partitions the inside of the tank and is formed with tube fitting notches that fit on to a tube partitioning portion, at approximately the center of the intake/outlet portion of each tube element.

Description: The present invention relates to a heat exchanger mainly used in an air conditioning system for vehicles and, in particular, to a heat exchanger according to the preamble of claim 1. Among heat exchangers used in air conditioning systems for vehicles in the prior art. the type of heat exchanger in which a seperate tank is mounted at an end of the heat exchanger core is known e. g. from JP - A - 5-1896, which forms the starting point of the present invention. According to the above reference, it is necessary to form intake/outlet portions that are shaped to fit the insertion holes formed in the tank in order to insert these intake/outlet portions of the tube elements into the tank, where heat exchanging medium flows in and out. The shape of the tube cross section of the tube elements in the vicinity of the intake/outlet portions and the shape of the tube cross section in the area extending from the intake/outlet ports to the vicinity of the U-turn in the flow path are generally different from each other in the prior art. However, in a heat exchanger disclosed in the reference mentioned above a plurality of variations may be set for the length of the tube elements, depending upon the installation location or the capacity of the heat exchanger. In order to support such variations, it is necessary to provide a different die for the forming of formed plates for each variation of tube element length. Furthermore, it is necessary to change automated assembly production lines to correspond to each different length of tube elements required. Because of this, when manufacturing a heat exchanger in a variety of sizes by using tube elements of different lengths, the costs of the dies and of changes in automated production assembly lines become very great, presenting a serious problem in production costs. The DE - A - 38 03 599 discloses a heat exchanger with a plurality of tube elements having spaced inlet/outlet portions which are inserted in separate inscrtion holes of a tank. The EP - A - 0 113 003 discloses a heat exchanger with a plurality of tube elements having pipe-like. spaced connecting portions which are inserted into separate insertion holes of a tank. Object of the present invention is to provide a heat exchanger in which it is relatively easy to accommodate variations in the length of the tube elements so that the heat exchanger that can be provided in a plurality of sizes, and to do so at low manufacturing costs. The above object is achieved by a heat exchanger according to claim 1. Preferred embodiments are subject of the subclaims. Preferably, the heat exchanger comprises tube elements, each of which is provided with a pair of intake/outlet ports formed at one end parallel to each other and a U-shaped heat exchanging medium passage that communicates between these intake/outlet ports; fins provided alternately between a plurality of tube elements; a tank into which the intake/outlet portions of the tube elements are fitted an a partitioning plate provided in the tank, which blocks of one intake/outlet port of each tube element from the other and also separates the inside of the tank into an intake side, which communicates with one side of the intake / outlet portions of the tube elements and an outlet side, which communicates with the other side of the intake / outlet portions of the tube elements. In each of the tube elements, the shape of the tube cross section extending from the intake / outlet ports to the vicinity of the area of the U-turn in the heat exchanging medium passage is consistent. The partitioning plate is provided with tube fitting notches that are fitted on to the tube partitioning portions of the tube elements. In other words, in the heat exchanger according to the present invention, the heat exchanger core is constituted by laminating a plurality of tube elements, the shape whose tube cross section is consistent from the intake / outlet ports to the vicinity of the flow path U-turn, alternately with fins. The intake / outlet portions of the various tube elements of the heat exchanger core are inserted into a tank that is provided separately, and tube fitting notches are provided toward the heat exchanger core in the partitioning plate that divides the inside of the tank, that fit on to the tube partitioning portions that are formed at approximately the center of the intake / outlet portion of the tube elements. Consequently, since, according to the present invention, the shape of the tube cross section of the tube elements in the area extending from the intake / outlet ports to the vicinity of the flow path U-turn area is consistent, tube elements of varying lengths can be formed by first forming the plates for a tube element of a given length and then by cutting the plates at various points, thereby increasing the possible variations of the tube elements. In addition, since the shape of the cross section of the front ends of the intake / outlet ports remains unchanged regardless of where the tube element is cut, it requires no change in the method of assembling the heat exchanger, or to be more specific, the method of inserting the tube elements into the insertion holes formed in the tank. In short, since the shape of the cross section of the front ends of the intake / outlet ports of the tube elements remains the same after cutting, when mounting tube elements to the tank by inserting the front ends of the intake / outlet ports of the tube elements into the tank and inserting the partitioning portions of the tube elements into the tube fitting notches provided in the partitioning plate of the tank, there is no difference in the procedure with or without cutting. In addition, when dividing the intake / outlet ports of the tube elements into the intake side and the outlet side with the partitioning plate of the tank, since the shape of the tube elements after cutting remains the same as before cutting, the work can be conducted in the same manner as it would without cutting. Consequently, even if identical work is performed on uncut tube elements and cut tube elements, there will be no leak of heat exchanging medium in the cut tube elements just as there would be no leak in uncut tube elements. Alternatively, the heat exchanger may comprise tube elements, in each of which the shape of the tube cross section extending from the intake / outlet ports to the vicinity of the flow path U-turn area is basically consist ent, at least one indented portion for cutting, which is indented from the outside of the tube toward the inside, is provided at a given location along the length of the tube element, whereby a tube element of a specific length is formed by cutting at a given indented portion for cutting and the shoulder part of the remaining part of the indented portion for cutting functions as a tank contact portion; fins alternately provided between a plurality of tube elements; a tank into which the intake / outlet ports of the tube elements are fitted and a partitioning plate provided in the tank, which blocks off one side of the intake / outlet portions of the tube elements from the other and which also separates the inside of the tank into an intake side, which communicates with one side of the intake / outlet portions of the tube elements, and an outlet side, which communicates with the other intake / outlet portions of the tube elements. The tube elements are mounted by placing the tank contact portions of the tube elements into contact with the lower portion of the tank with the tube fitting notches provided in the partitioning plate that partitions the inside of the tank fitted onto the tube partitioning portions at approximately the center of the intake / outlet portion of the tube elements. In other words, this heat exchanger is constituted with a heat exchanger core which, in turn, is constituted by laminating a plurality of tube elements that have a consistent tube cross section shape from the intake / outlet ports to the vicinity of the flow path U-turn, at least one indented portion for cutting that is indented from the outside of the tube toward the inside in the middle of the tube and a tank contact portion, in which intake / outlet ports are constituted by cutting at a given indented portion for cutting in the tube elements, alternately with fins. The intake / outlet portions of the tube elements in the heat exchanger core are inserted into a tank that is provided separately and the tube elements are mounted by placing the tank contact portions of the tube elements in contact with the lower portion of the tank and fitting the tube fitting notches provided toward the heat exchanger core in the partitioning plate, which partitions the inside of the tank, onto the tube partitioning portions at approximately the center of the intake / outlet portions of the tube elements. As a result, in this heat exchanger, the shape of the tube cross section from the intake / outlet ports to the vicinity of the flow path U-turn of each tube element is consistent and an indented portion for cutting provided with a tank contact portion for positioning is formed along the length of the tube. In this structure, more variations in the length of the tube elements can be achieved by cutting at an indented portion for cutting at a given position and, at the same time, when inserting tube elements thus cut, the lower surface part of the indented portion for cutting functions as the tank contact portion so that the position of the insertion of the tube element can be determined at the tank lower surface portion. Furthermore, since the shape of the cross section of the front ends of the intake / outlet ports of the tube elements thus cut is not changed, when mounting tube elements onto the tank by first inserting the front ends of the intake / outlet portions of the tube elements into the tank and inserting the partitioning portions of the tube elements into the tube fitting notches provided in the partitioning plate of the tank, the intake / outlet ports of the tube elements are divided into intake side ports and outlet side ports by the partitioning plate in the tank, thus ensuring that no leak of heat exchanging medium will occur. At the same time, whatever length the tube element is cut to, the shape of the cross section of the intake / outlet ports remain as it was before the cut. Therefore, the assembly method of the heat exchanger does not change, either. Consequently, according to the present invention, by cutting a tube element whose length is originally set at a specific length at a given position, a heat exchanger comprising tube elements of a plurality of variations in length can be easily manufactured. FIG. 1 is a schematic diagram of a heat exchanger according to the present invention in a first embodiment; FIG. 2 is a perspective view of a tube element used in the heat exchanger shown in FIG. 1; FIG. 3 is a cross section of a part of the heat exchanger shown in FIG. 1; FIG. 4 is a exploded perspective view of a part of the heat exchanger shown in FIG. 1; FIG. 5 is a front view of a tube element used in a heat exchanger according to the present invention in a second embodiment; FIG. 6 is a cross section of a part of the heat exchanger shown in FIG. 5, which illustrates a state of assembly, and FIG. 7 is an exploded perspective view of a part of a exchanger according to the present invention in a third embodiment. The following is an explanation of the embodiments of the present invention in reference to the drawings. FIGS. 1 through 4 show a heat exchanger in the first embodiment of the present invention. The heat exchanger comprises a heat exchanger core 3 formed by laminating tube elements 1, each of which is provided with a roughly U-shaped heat exchanging medium passage, alternately with corrugated fins 2 and a tank 5 that is connected to one end of the heat exchanger core 3. The tank 5 is provided with intake / outlet pipes 4 and 4. As shown in FIG. 2, each tube element 1 is approximately rectangular and is formed by bonding two formed plates 10 and 10 face-to-face. The formed plates10 are formed through so-called press forming and are constituted of aluminum or an aluminum alloy, dressed with a brazing material on the surface. The formed plates 10 are each provided with an projection 11 that extends from one end of the formed plate to the vicinity of the other end, and an indented portion for heat exchanging medium passage formation 12 that is formed around the projection 11 except at one end. A tube element 1 is constituted by bonding two such formed plates 10 and 10 face-to-face. Inside the tube element 1, a roughly U-shaped heat exchanging medium passage 15 is formed with the projections 11 and the indented portions for heat exchanging medium passage formation 12. With this, at one end of the tube element 1, intake / outlet ports 16a and 16a for heat exchanging medium open, and in the vicinity of the other end a flow path U-turn area 17 is formed. In addition, at approximately the center of the tube element 1, a tube partitioning portion 18 is formed with the projections 11 that are bonded face-to-face. This ensures that the heat exchanging medium that flows in through one of the intake / outlet ports 16a will flow to the other of the intake / outlet ports 16a after making a U-turn in the flow path U-turn area 17. Since, in the tube element 1 structured as explained above, the shape of the tube cross section is consistent from the intake / outlet portion 16 at one end, where the intake / outlet ports 16a and 16a open, to the flow path U-turn area 17 (to the end of the projections 11), its cross section remains the same even if the tube element 1 is cut to an arbitrary length. Consequently, when setting a plurality of variations in the length of the tube elements to be used in one heat exchanger, the tube element described above only has to be cut at an appropriate position (length) to correspond to a given variation and then the tube element 1 that has been cut to support that particular variation can be mounted to the heat exchanger. Note that, since no matter what length the tube element 1 is cut to, the shape of the cross section of the front end of the intake / outlet portion 16 formed by the intake / outlet ports 16a and 16a, remains unchanged, and therefore, the cutting does not affect the method of assembling the heat exchanger in any way whatsoever, as explained in detail later. The tank 5 is constituted with a pipe-side tank member 20 and a tube-side end plate 21, as shown in FIGS. 1, 3 and 4. The tank 5 is also provided with a partitioning plate 22 that partitions the inside of the tank 5. The pipe-side tank member 20 has a box-like shape with one side open and pipe insertion holes 23 (shown in FIG. 1), for inserting the intake / outlet pipes 4 and 4, are bored in the upper surface, which is the side surface opposite the open side. The tube-side end plate 21 is formed through so-called press forming and is constituted of aluminum or an aluminum alloy dressed with a brazing material on its surface. The tube-side end plate 21 is constituted of a flat plate with its edges bent toward the pipe-side tank member to form a fitting frame 25, into which the pipe-side tank member 20 is fitted. Also, a plurality of tube element insertion holes 27, for inserting the intake / outlet portions 16 of the tube elements 1, are bored over specific intervals M1 in the bottom surface portion 26 of the tube-side end plate. The intake / outlet portions 16, which constitute the upper ends of the tube elements 1, and the tube partitioning portions 18 can be inserted into the tube element insertion holes 27 as they are, and a burr 30 extends below the tube element insertion holes 27, to improve the brazing contact with the tube elements 1. The partitioning plate 22 divides the inside of the tank 5 and is provided at approximately the center in the direction of the width of the tank, with tube fitting notches 33 for fitting on to the tube partitioning portion 18 at approximately the center of the intake / outlet portion 16 of each tube element 1, formed by notching at its lower edge. The interval between these tube fitting notches 33 is set to correspond to the interval M1 of the tube element insertion holes 27 described earlier. Note that a protrusion 34a is formed at both sides of each tube fitting notch 33, to be fitted into the indented tube partitioning portions 18 so that the gaps between the tube partitioning portions 18 and the tube element insertion holes 27 are filled. Consequently, when the tube elements 1 are inserted in the tube element insertion holes 27 of the tank 5, the tube partitioning portions 18 of the tube elements 1 are fitted inside the tube fitting notches 33 of the partitioning plate 22. As a result, with the heat exchanger described above, since it is possible to mount the tube elements 1 after setting their lengths arbitrarily by cutting, a heat exchanger with specific variations in the length of the tube elements 1 can be constituted with relative ease and at low cost. In other words, the lengths of the tube elements 1 can be varied simply by changing the length of a single type of tube element formed in a single metal die and it becomes possible to produce a heat exchanger with tube elements of differing lengths (different variations) on a single automated assembly production line. In addition, since the tube partitioning portion 11 of each tube element 1 is brazed while fitted into a tube fitting notch 33 of the partitioning plate 22 inside the tank 5, a fillet is formed on the tank at the time of brazing the tube-side end plate 21 of the tank 5 and the tube elements 1. Consequently, there is no danger of the brazing material being drawn away to the fins 2, and thus, brazing material shortage is prevented, ensuring good brazing. Next, another example of the heat exchanger according to the present invention is explained in reference to FIGS. 5 and 6. Note that components with identical structures to those in the first embodiment are assigned the same reference numbers and their explanation is omitted here. The difference between the heat exchanger in the second embodiment according to the present invention and the one in the first embodiment described earlier is that, as shown in FIG. 5, a plurality of indented portions for cutting 41 are provided at appropriate locations toward the outside in the direction of the width of a tube element 40. The other structural features are identical to those in the heat exchanger in the first embodiment. In each tube element 40, at least one indented portion for cutting 41, which is indented from the outside of the tube to the inside is provided along the length of the tube whose cross section shape is formed consistent from the intake / outlet ports 16a and 16a formed at the intake / outlet portion 16 to the flow path U-turn area 17, and the length of the tube element 40 can be set arbitrarily by cutting at a given indented portion for cutting 41 to a specific length (for instance, L1, L2, L3 or L4 in the figure). In this embodiment, the shape of the cross section of the front ends of the intake / outlet ports 16 and 16 remains unchanged after the tube element 40 is cut at the specific position mentioned above, and also, under the indented portion for cutting 41, a tank contact portion 42 for positioning the tube element 40 through its contact with the tube-side end plate 21 of the tank 5 is formed after the cut. The method of assembling the heat exchanger does not change because of the cutting in any way whatsoever (see FIG. 6). In addition, the tube elements 40 that are inserted in the tube element insertion holes 27 of the tank 5 are brazed with their tube partitioning portions 18 fitted into the tube fitting notches 33 of the partitioning plate 22, as in the case of the heat exchanger in the first embodiment (see FIG. 6). As a result, with the heat exchanger described above, since it is possible to mount the tube elements 40 after setting their lengths at arbitrary lengths by cutting them at a specific position, a heat exchanger with a number of variations in the length of the tube elements 40 can be constituted with relative ease and at low cost. In other words, the lengths of the tube elements 40 can be varied simply by changing the length of a single type of tube element formed in a single metal die and it becomes possible to produce a heat exchanger with differing lengths of tube elements (different variations) on a single automated assembly production line. In addition, the shoulder of the remaining portion of the indented portion for cutting 41 that has been cut functions as a tank contact portion 42 which performs positioning by placing the tube element 40 in contact with the tube-side end plate 21 of the tank 5. With the positioning of the tube elements 40 performed with the tank contact portions 42 coming in contact with the tube-side end plate 21, the tube elements 40 do not hit the partitioning plate 22 and consequently, no gap is formed between the partitioning plate 22 and the tube-side end plate 21 during assembly, which in turn prevents leak inside the tank 5. Furthermore, since, in this heat exchanger, the indented portions for cutting of the tube elements 40 that have not been cut remain intact, and these remaining indented portions for cutting 41 promote turbulent flow of the heat exchanging medium, improving the efficiency of heat exchange. Yet another embodiment of the heat exchanger according to the present invention is explained below in reference to FIG. 7. In this embodiment, a protrusion 36, which fits into the tube partitioning portion 18, is formed on both sides of each tube element insertion hole 27 at approximately the middle thereof. With this, the shape of the tube element insertion hole 27 is formed identical to the shape of the cross section of the tube element 1. Because the protrusions 36 are provided, no protrusion is formed at the sides of the tube fitting notches 33 of the partitioning plate 22 and, therefore, only the tube fitting notches 33 are formed, and the shape of the partitioning plate 22 is simplified. The other features have identical structures to those in the first embodiment, are assigned the same reference numbers and their explanation is omitted here. As has been explained, with the heat exchanger according to the present invention described above, since it is possible to mount the tube elements after setting their lengths arbitrarily by cutting, even when constituting a heat exchanger with arbitrary variations in length, the lengths can be achieved by simply changing the length of a single type of tube element formed in a single metal die and it becomes possible to produce a heat exchanger with differing lengths of tube elements (different variations) on a single automated assembly production line. In addition, since the tube partitioning portion of each tube element is brazed while fitted into a tube fitting notch of the partitioning plate inside the tank, a fillet is formed on the tank at the time of brazing the tube-side end plate of the tank and the tube elements. Consequently, there is no danger of the brazing material being drawn away to the fins, and a brazing material shortage is thus prevented, ensuring good brazing. At the same time, since the intake / outlet portion of the tube element is divided into an intake side and an outlet side by the partitioning plate of the tank, no leak of heat exchanging medium occurs. In addition to the advantages described above, with the tank contact portions formed under the indented portions for cutting that have been cut are placed in contact with the tube-side end plate of the tank to determine the position of the tube elements, the tube elements 40 do not hit the partitioning plate 22 and, consequently, no gap is formed between the partitioning plate 22 and the tube-side end plate 21 during assembly, which, in turn, prevents leakage inside the tank 5. Furthermore, since, in this heat exchanger, the indicate portions for cutting that have not been cut in each tube element remains as is, these remaining indented portions for cutting promote turbulent flow of the heat exchanging medium and improves the efficiency of heat exchange.

Claims: Heat exchanger comprising: a plurality of tube elements (1, 40) each of which having an intake/outlet portion (16) formed at one end of said tube element (1, 40) with a pair of intake/outlet ports (16a) opening parallel to each other, a tube partitioning portion (18) extending from said intake/outlet portion (16) to a portion adjacent to the other end of said tube element (1, 40), and a U-shaped heat exchanging medium passage (15) formed around said tube partitioning portion (18) and communicating between said intake/outlet ports (16a); fins (2) provided alternately between said tube elements (1); and a tank (5) comprising a pipe tank member (20) with intake/outlet pipes (4), and a tube side end plate (21) with tube element insertion holes (27) in which said intake/outlet portions (16) of said tube elements (1, 40) are inserted, wherein a partitioning plate (22) is located in said tank (5) to partition the space inside said tank (5) into an intake side and an outlet side, each of which communicates with said intake and outlet ports (16a), respectively; characterized in that said partitioning plate (22) is provided with a plurality of tube fitting notches (33), wherein the intake/outlet portion (16) of each tube element (1, 40) is inserted into one respective tube element insertion hole (27) such that the tube partitioning portion (18) extends into a respective tube fitting notch (33). Heat exchanger according to claim 1, characterized in that said tank (5) has a box shape with one open side which is closed by said tube side end plate (21). Heat exchanger according to claim I or 2, characterized in that the tube element insertion holes (27) are provided with protrusions (36) filling up dents of said tube elements (1, 40) in the area of said tube partitioning portions (18). Heat exchanger according to claim 1 or 2, characterized in that said partitioning plate (22) is provided with protrusions (34a) on both sides of each tube fitting notch (33), wherein said protrusions (34a) extend along a respective tube partitioning portion (18) into the respective tube element insertion hole (27) and fill up dents of the respective tube element (1, 40) in the area of the respective tube partitioning portion (18). Heat exchanger according to any one of the preceding claims, characterized in that the shape of the tube cross section is formed consistently between said intake/outlet ports (16a) and the other end of said tube partitioning portion (18) in each tube element (1). Heat exchanger according to any one of claims 1 to 4, characterized in that said tube elements (40) are formed by cutting between indented portions (41) provided on both longitudinal sides of said tube elements (40), wherein a shoulder portion of the remaining portion of said indented portion (41) is provided with a tank contact portion (42), wherein the shape of the cross section is consistent in portions of each tube element (40) in which said indented portions (41) are formed. Heat exchanger according to any of the preceding claims, characterized in that each of said tube elements (1, 40) is formed by bonding a pair of formed plates (10) face-to-face, wherein each formed plate (10) is provided with an indented portion for heat exchanging medium passage formation (12) for forming said intake/outlet portion (16) and said heat exchanging medium passage (15), and a projection (11) forming said tube partitioning portion (18). Heat exchanger according to any one of the preceding claims, characterized in that a burr (30) projects out around each of said tube element insertion holes (27) toward said tube elements (1, 40).

Inventors: ETO YOSHIHISA, KOBINATA HIROSHI, KUWABARA SHOJI, SEKIYA YOSHIHIRO, SUGITA TAKASHI, TSUBAKIDA TOSHIO, ETO, YOSHIHISA, KOBINATA, HIROSHI, KUWABARA, SHOJI, SEKIYA, YOSHIHIRO, SUGITA, TAKASHI, TSUBAKIDA, TOSHIO, Eto, Yoshihisa, c/o Zexel Corp. Konan Factory, Kobinata, Hiroshi,c/o Zexel Corp. Konan Factory, Kuwabara, Shoji, c/o Zexel Corp. Konan Factory, Sekiya, Yoshihiro,c/o Zexel Corp. Konan Factory, Sugita, Takashi, c/o Zexel Corp. Konan Factory, Tsubakida, Toshio, c/o Zexel Corp. Konan Factory
Applicants: ZEXEL CORP, ZEXEL CORPORATION
Application year: 1995
Main classification: F28D1
IPC codes: F28D1, F28F9