Heat exchanger assembled without brazing in which adhesive is used to seal tube end portions and an end plate

Abstract: In a mechanically assembled type heat exchanger, in which an end portion of an oval tube (14) is inserted into a barring hole (16a) of a core plate (16) and expanded to be press fit to the core plate (16). Then adhesive (24) is potted on the core plate (16) for sealing the press fit portion in the end of the tube (14). A reinforcing member (16e, 16f, 16g, 16h, 16i, 16j) is formed around the barring hole (16a) for increasing the rigidity of the core plate (16) so as to improve the durability of sealing.

Description: The present invention relates to a heat exchanger according to the preamble of claim 1. Such a heat exchanger is disclosed by US-A-4,881,594. This known heat exchanger comprises a core plate connected to an opening surface of a tank, said core plate having a hole for receiving an end portion of a tube, which is press-fitted to said core plate. Further, a reinforcing member is arranged at least around said hole for increasing the rigidity of said core plate. Heat exchangers in which adhesive is used to seal the combined portion are known. According to these conventional structures, a supporting structure at the combined portion is such as shown in FIGS. 17A-17C, for example. That is, after both ends of a cylindrical tube 14 being inserted into a circular barring hole 16a of a core plate 16, the tube 14 is expanded so that outer peripheral surface of both ends of the tube 14 (the combined portion) are press fit with inner peripheral surface of the barring hole 16a of the core plate 16, thus, the tube 14 and the core plate 16 are integrated. Next, adhesive 24 is potted at an air flowing side face (right side face of FIG. 17B) of the core plate 16 to seal the press fit combined portion between the tube 14 and the core plate 16. Thus, water leak from this press fit combined portion is prevented. However, according to the result of study of tests with respect to a sample of above-mentioned mechanically assembled type heat exchanger in which the combined portion is sealed by potting the adhesive 24, it was found that a difficulty of sealing at the combined portion sealed by adhesive is caused by the following reason. When the heat exchanger is under the working condition, a pressure inside the heat exchanger rises, thereby, the core plate 16 is deformed as shown in FIG. 18B. Two-dot chain line A in FIG. 18B shows the core plate 16 which is not effected by the inside pressure, and solid line B shows the core plate 16 which is deformed by the inside pressure. Since the inner peripheral surface of a barring hole 16a of the core plate 16 is press fit to both ends of the tube 14, in case that pressure is increased inside a tank chamber constructed by the core plate 16 and a resinous upper tank 12 (or lower tank 13), as shown in FIG. 18A, out of the core plate 16, a portion of the core plate 16 in a groove 16b side which is connected to the tank 12 (tank 13) by caulking is deformed toward the tank 12 (tank 13), for pressure receiving area in the tank 12 (tank 13) side is large. Due to the above-mentioned deformation of the core plate 16, adhesive 24 potted on the air flowing side surface of the core plate 16 is effected by stretching stress. Under this stretching condition, since the intermolecular distance of the adhesive becomes large, intruding speed of any other molecule consisting of the fluid inside the tank (in case of radiator, engine coolant including anti-freeze ingredient and anti-corrosive ingredient, and so on) into the adhesive 24 increases. Furthermore, when molar volume of the above molecular becomes decreased by the rise in inside pressure, the intruding speed of the molecule into the adhesive becomes more increased. Thus, deterioration of the adhesive 24 itself proceeds, and cohesive destruction of the adhesive 24 and exfoliation of the bonded surface arise. As a result, sealing difficulty at the combined portion (being denoted as "a" in FIG. 18B) and the leak of the fluid inside tank (water leak) arise. Especially, recently, for reducing cost and weight, reducing the thickness (t) of an aluminum alloy core plate 16 (for example, 0.8-1.2 mm) and replacing a cylindrically shaped tube with an oval tube (the ratio of long diameter to short diameter: about 2-5) are greatly required. Accordingly, rigidity of the core plate 16 is reduced and the deformation is likely to be increased, so, the sealing difficulty at the combined portion becomes remarkable. SUMMARY OF THE INVENTION An object of the present invention is to improve durability of sealing in a heat exchanger in which a combined portion is sealed by potting adhesive. This object is solved by the features cited in claim 1. According to one aspect, the present invention achieves the above object by adopting a reinforcing structure to reinforce the tube combined portion at the core plate. Namely, for achieving the above object, according to the present invention, in a heat exchanger in which an end portion of a tube is inserted into a hole formed on a core plate, and the tube is press fit to the core plate by expanding the inside diameter of the tube, after that, adhesive is potted on the core plate for sealing the press fit portion of the end portion of the tube, and an concave and convex formed reinforcing member located at least around the hole of the core plate is provided. By this reinforcing member, the rigidity of the core plate is increased. Thereby, when an inside pressure of the heat exchanger affects on the core plate, a deformation of the core plate, especially, a deformation around the hole to which the tube is press fit can be reduced efficiently. So, cohesive destruction of the adhesive itself and exfoliation of the bonded surface due to the deformation of the core plate caused by the inside pressure are reduced. Accordingly, a good sealing function at the press fitted portion of the tube end is guaranteed in the long period by the adhesive potted on this press fit portion. Alternatively, for achieving the same object, according to the present invention, in a heat exchanger in which an end portion of a tube is inserted into a hole formed on a core plate, and the tube is press-fit to the core plate by expanding the inside diameter thereof. After that, adhesive is potted on the core plate for sealing the press-fit portion of the end portion of the tube and, finally, a reinforcing member which is formed of an independent plate material of the core plate is connected to at least around said hole integrally. By this reinforcing member, the rigidity of the core plate is increased. Thereby, the rigidity of the core plate is increased due to the reinforcing member formed of an independent plate material to the core plate, so that, a good sealing function at the press fit portion of the tube end can be guaranteed in the long period by the adhesive potted on this press fit portion. BRIEF DESCRIPTION OF THE DRAWINGS Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiments thereof when taken together with the accompanying drawings in which: FIG. 1 is a front view of a heat exchanger according the first embodiment of the present invention; FIG. 2 is a front cross sectional view of the tank of a heat exchanger relevant to understand the invention; FIG. 3 is a side cross sectional view transverse to FIG. 2; FIG. 4A is an enlarged plan view of a principal part of the tank of a heat exchanger relevant to understand the invention, and FIG. 4B and FIG. 4C are cross sectional views of shown FIG. 4A; FIG. 5A is an enlarged plan view of a principal part of the tank of a heat exchanger relevant to understand the invention, and FIG. 5B and FIG. 5C are cross sectional views of shown FIG. 5A; FIG. 6A is an enlarged plan view of a principal part according to an embodiment of the present invention, and FIG. 6B and FIG. 6C are cross sectional views of shown FIG. 6A; FIG. 7A is an enlarged plan view of a principal part according to an embodiment of the present invention, and FIG. 7B and FIG. 7C are cross sectional views of shown FIG. 7A; FIG. 8A is an enlarged plan view of a principal part according to an embodiment of the present invention, and FIG. 8B and FIG. 8C are cross sectional views of shown FIG. 8A; FIG. 9A is an enlarged plan view of a principal part according to an embodiment of the present invention, and FIG. 9B and FIG. 9C are cross sectional views of shown FIG. 9A; FIG. 10A is an enlarged plan view of a principal part according to an embodiment of the present invention, and FIG. 10B and FIG. 10c are cross sectional views of shown FIG. 10A; FIG. 11A is an enlarged plan view of a principal part according to an embodiment of the present invention, and FIG. 11B and FIG, 11C are cross sectional views of shown FIG. 11A; FIG. 12A is an enlarged plan view of a principal part according to an embodiment of the present invention, and FIG. 12B and FIG. 12C are cross sectional views of shown FIG. 12A; FIG. 13A is an enlarged plan view of a principal part according to an embodiment of the present invention, and FIG. 13B and FIG. 13C are cross sectional views of shown FIG. 13A; FIG. 14A is an enlarged plan view of a principal part according to an embodiment of the present invention, and FIG. 14B and FIG. 14C are cross sectional views of shown FIG. 14A; FIG. 15A is an enlarged plan view of a principal part according to an embodiment of the present invention, and FIG. 15B and FIG. 15C are cross sectional views of shown FIG. 15A; FIG. 16A is an enlarged plan view of a principal part according to an embodiment of the present invention, and FIG. 16B and FIG. 16C are cross sectional views of shown FIG. 16A; FIG. 17A is an enlarged plan view of a principal part according to the related art, and FIG. 17B and FIG. 17C are cross sectional views of shown FIG. 17A; and FIG. 18A is a cross sectional view of a principal part of a conventional radiator, and FIG. 18B and FIG. 18C are enlarged cross sectional views of the conventional radiator. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings, preferred embodiments of the present invention will be described. A heat exchanger used for a car radiator is constructed, as shown in FIG. 1, by a core portion 11 to carry out heat exchange between an engine coolant and a cooling air (outside air), an upper tank 12, and a lower tank 13, in general. The core portion 11 is constructed by a plurality of tubes 14, plate fins 15, an upper core plate 16, and a lower core plate 16. Theses parts 14, 15, 16 of the core portion 11 are made of a metal which has a high heat conductivity and a high corrosion resistance, such as an aluminum alloy. Further, as shown in FIG. 2, the tube 14 is formed into oval shape in cross section, and its combined portions (both ends portion) are press fit to each barring hole 16a formed into cross sectional oval shape of the upper and lower tank 16. In this, the "barring hole" 16a is defined as a shape provided with a protrusion portion protruding into inside the tank (water side) from edge of a cross sectional oval shape hole. Both end portions of the tube 14 are opened in each chamber inside the upper tank 12 and the lower tank 13. It is to be noted that the oval shape in this specification includes an ellipse shape formed by a curve shape consisting of first circular arc whose radius of curvature is large and second circular arc whose radius of curvature is small, or an elongated oval shape formed by a circular arc and a liner line, etc. The example disclosed in some Figures is the ellipse shape. The oval tubes 14 are arranged in such a manner that a major axis direction is parallel to a cooling air flowing direction C (refer to FIG. 4B), and many parallel tubes 14 are arranged in the lateral direction in FIG. 1 in order that a predetermined distance between adjacent tubes is provided. Setting a ratio of the major axis direction size L1 the oval tube 14 L1 to the minor axis direction size L2 (L1/L2) is about 2-5 is preferable for reducing a pressure resistance in the air side, for enhancing the heat exchange efficiency, and for simplifying a tube expanding operation. While, many plate fins 15 are stacked in a predetermined pitch in a tube axis direction in FIG. 1. This pitch between adjacent plate fins 15 are set by protruded pins (not illustrated) integrated with the plate fin 15, and supported. Also, in the plate fin 15, oval shape barring holes (not illustrated) corresponding to the oval shape tube 14 are formed, and the oval shape tubes 14 are inserted into the oval shape barring holes, thus, the plate fin 15 is press fit to the oval shaped tube 14 in the barring hole. Further, in the plate fin 15, a plurality of louvers (not illustrated) are formed diagonally in the well known manner. Further, an outer shape of the upper (lower) core plate 16 is in an elongated rectangular shape, and this core plate 16 is provided with the above-described cross sectional oval shape barring holes 16a at the center region, and as shown in FIG. 2 and FIG. 3, a groove 16b into which a sealing packing 25 is installed is formed at an outer periphery of the core plate 16. The packing 25 is made of elastic material such as a rubber. The groove 16b is formed along outer periphery of the core plate 16, and it makes a closed circuit. At a lid portion of the periphery of the core plate 16, a plurality of clips 16c for caulking are formed in all round. The upper tank 12 and the lower tank 13 are made of resin having a high heat resistance and strength etc. and formed into box shape having a opening surface 22. An inlet pipe 18 into which a coolant from the car engine is introduced and a coolant feeding port 19 etc. are integrated with the upper tank 12, and a well known pressurizing cap 20 is attached to the coolant feeding port 19 removably. Also, an outlet pipe 21 from which the coolant flows out is integrated with the lower tank 13. Further, after setting the opening surface 22 of the upper and lower tanks 12 and 13 on the sealing packing 25, by press caulking the clip 16c of the core plate 16 onto a shoulder portion 22a of the opening surface 22, the packing 25 is subjected to be compressed elastically. Next, the supporting structure of the core plate 16 in the first embodiment will be explained in more detail. As shown in FIGS. 6A-6C, out of the main flat portion 16d, a combined portion 16d of the barring hole 16a is located on the same plane as the main flat portion 16d (as shown in FIG. 6B), and between the combined portion 16d' and the main flat portion 16d, a rib 16g protruding toward the air flowing side of these portions 16d', 16d is formed. By the rib 16g, the rigidity of the core plate 16 in the main axis direction of the oval tube become increased. It is to be noted that, the thickness of the core plate 16 according to the present embodiment is 0.8-1.2 mm, and the thickness of the tube 14 is 0.25-0.50 mm. Next, an assembling method of the heat exchanger of the present embodiment will be explained. At first, the predetermined number of the plate fins 15 are stacked in a predetermined pitch in the upper and lower direction in FIG. 1, and the oval tubes 14 are inserted into each barring hole (not illustrated) of the plate fins 15. Next, by inserting an expanding instrument (not illustrated) into the oval tube 14 and expanding inside diameter of the oval tube 14, the outer peripheral surface of the oval tubes 14 are press fit to the respective inner surface of the barring hole of the plate fins 15. Thus, the plate fins 15 are fixed to the oval tubes 14. Both upper and lower ends of the tube 14 are inserted into the barring hole 16a of the upper and lower core plates 16 respectively. By inserting the expanding instrument (not illustrated) into the both upper and lower ends of the oval tube 14, and also expanding inside diameter of the oval tube 14, both upper and lower ends of the oval tube 14 are press fit to the inner surface of the barring hole 16a of the core plate 16, and both upper and lower ends of the oval tube 14 are fixed to the core plate 16. Out of the main flat portion 16d of the core plate 16, around the tube combined portion of the air flowing side surface (the right side surface in FIG. 4B) the adhesive 24 is potted. Here, as the adhesive 24, a rubber type adhesive, more specifically a silicon rubber type adhesive, having high resistance for heat and chemical such as anti-freezing ingredient and anti-corrosive ingredient etc., and so on, is preferable. Further, since the air flowing side surface of the step portion 16e is formed into cup shape which stores the adhesive 24 around the oval tube 14, the adhesive is firmly stored around the oval tube 14. The packing 25 is installed into the groove 16b of the upper and lower core plate 16. The tank 12 and 13 are assembled to the upper and lower core plates 16 such that the opening surfaces 22 and 23 of the upper and lower resin tanks 12 and 13 are located on the packing 25. Finally, the clip 16c of the core plate 16 is press caulked to the shoulder portion 22a of the opening surface 22 under the condition that the opening surface of each upper and lower tanks 12 and 13 are press fixed to the sealing packing 25. Thereby, the upper and lower core plate 16 and the upper and lower tank 12 and 13 are connected integrally, and the sealing packing 25 is press fixed to the opening surface 22 and the groove 16b by elastically compressed deformation. By the above-described operation, the assembling of the entire heat exchanger is completed. Next, an operation of the above-described component will be explained. The engine coolant flowing into the upper tank 12 through the inlet pipe 18 is introduced into the tube 14 through the upper end port of the oval tube 14 which is opening inside the upper tank 12. During the coolant is passing through this tube 14, the coolant carries out a heat exchange with the cooling air through the plate fin 15 and is cooled down. The engine coolant flows into the lower tank 13 after passing through the tube 14, and it flows out from the outlet pipe 21 and returns to the engine. Here, the radiator according to the present embodiment is assembled by mechanically assembling method without brazing as mentioned above, however, the packing 25 is compressed elastically between the upper (lower) tank 16 and the groove 16b and performs a sealing function, so the prevention of the water leak from the opening surface 22 of the upper and lower tank 12, 13 is firmly obtained. While, when the car engine is working, inside an engine cooling recirculation passage, an internal pressure (for example, 88 kPa) arises by a water pump operation. Thus, the core plate 16 tends to be deformed by this internal pressure. However, in the present embodiment, the step portion 16e is integrally protruded from the surface of the main flat portion 16d toward the protruding direction of the barring hole 16a (tank inside direction) in the entire outer peripheral side of the protrusion portion of this barring hole 16a formed at the center region of the main flat portion 16d of the core plate 16. Since, the step portion 16e is formed, increasing the section modulus of the core plate 16 in the barring hole 16a region and increasing the geometrical moment of inertia are provided, whereby, the rigidity of the core plate 16 is increased efficiently. Thus, if the internal pressure under the car engine working affects on the core plate 16, the prevention of the deformation of the core plate 16, especially the deformation at the barring hole 16a region which is press fit by the tube 14, is efficiently obtained. So, the cohesive destruction of the adhesive 24 itself and the exfoliation of the bonded surface caused by the deformation based on the internal pressure of the core plate are reduced. Accordingly, at the press fit portion between the upper /lower core plate 16 and the upper/lower end portion of the tube 14, this adhesive 24 potted on this press fit portion can prevent the water leak in the long period. In another embodiment shown in FIGS. 7A-7C, the combined portion 16d' of the barring hole 16a of the core plate 16 is located on substantially the same plane as the main flat portion 16d, and between the combined portion 16d' of the barring hole 16a, a rib 16h protruding toward the water flowing side (the barring hole 16a protruding direction) is formed. According to this embodiment, by forming this rib 16h, increasing the section modulus of the core plate 16 in the barring hole 16a region is obtained, the rigidity of the core plate 16 is increased efficiency. In another embodiment shown in FIG. 8A-8C, a reinforcing member 26 partially formed with the core plate 16 is combined. This reinforcing member 26 is formed by an aluminum rectangular plate, and a perforation 26a formed in the center thereof is attached to an outer periphery side of the protrusion of the barring hole 16a of the core plate 16. This reinforcing member 26 and the core plate 16 are fixed to each other by expanding the protrusion of the barring hole 16a, which is done by expanding inside diameter of the both ends of the oval tube 14. By attaching the reinforcing member 26 as an independent part to the outer peripheral side of the barring hole 16a of the core plate 16, the rigidity of the core plate 16 in the barring hole 16a region is increased efficiently. It is for granted that the other connecting method of brazing or spot welding etc. can be used as a means for attaching the reinforcing member 26 to the core plate 16. In another embodiment shown in FIG. 9A-9C, the reinforcing member 26 as an independent part is arranged on the air flowing side face of the main flat portion 16d of the core plate 16 for increasing the rigidity of the core plate 16. Fixing between the reinforcing member 26 as an independent part and the core plate 16 can be done by the connecting method such as brazing or spot welding etc. In another embodiment shown in FIGS. 10A-10C, the oval barring hole 16a is protruded toward inside the tank (water side) from the main flat portion 16d of the core plate 16, and a rib 16i being parallel to the main axis direction (upper and lower direction in FIG. 10A) of the oval shaped barring hole 16a is formed in the center region between the adjacent barring holes 16a. This rib 16i is protruded toward the air flowing side (an opposite direction to the protruding direction of the barring hole 16a) from the main flat portion 16d, and formed covering all width area in the main axis direction (upper and lower direction in FIG. 10A) of the barring hole of the main flat portion 16d. By forming this rib 16i, increasing the section modulus of the core plate 16 and the rigidity of the core plate 16 is provided. In another embodiment shown in FIGS. 11A-11C, a rib 16j corresponding to the rib 16i in the seventh embodiment is formed to be protruded toward the protruding direction of the barring hole 16a (water side) from the main flat portion 16d of the core plate 16. In the embodiment in FIGS. 10A-10C, the rib 16i is formed covering the all width area in the main axis direction of the barring hole (upper and lower direction in FIG. 10A) of the main flat portion 16d. Contrary to this, in the embodiment shown in FIGS. 12A-12C, this rib 16i is set to be shorter than all width dimension of the main flat portion 16d in the main axis direction of the barring hole (upper and lower direction in FIG. 10A), and set to be a little longer than the dimension of the barring hole 16a in the main axis direction. In another embodiment shown in FIGS. 13A-13C, the rib 16j in the embodiment in FIGS. 11A-11C is set to be a little longer than the dimension of the barring hole 16a in the main axis direction. In another embodiment shown in FIGS. 14A-14C, the same rib 16j as described in the embodiment shown in Figs 10A-10C is formed and the combined portion 16d' of the barring hole 16a is located on the same plane as the main flat portion 16d (refer to FIG. 14B). Furthermore, between this combined portion 16d' and the main flat portion 16d, a rib 16g (a same rib as the rib 16g in FIGS. 6A-6C) protruding toward the air flowing side of these parts 16d', 16d is formed. According to this embodiment, in comparison with the embodiment in FIGS. 10A-10C, it is an advantage that an area for storing the adhesive can be made by forming the rib 16g. Furthermore, a a rigidity of the core plate 16 in the groove 16b side region can be increased due to an irregularity shape of the rib 16g and the main flat portion 16d. Whereby, increasing the caulking strength of the clip 16c of the core plate 16 can be attained. According to the embodiment in FIGS. 14A-14C, the ribs 16g are formed at both sides of the tube 14 in the main axis direction. Contrary to this, according to the another embodiment shown in FIGS. 15A-15C, the rib 16g at one side (an above side in the figure) is to be abolished, and at the other side of the oval tube 14 in its main axis direction, the combined portion 16d' of the barring hole 16a and the main flat portion 16d are formed on the same plane in a continuous manner. According to the another embodiment, the oval tube 14 in the embodiment in FIGS. 10A-10C is replaced with a cylindrical tube 14. According to the above-described embodiments, the barring hole 16a of the core plate 16 is protruded toward inside the tank (water flowing side). Contrary to this, protruding the barring hole 16a toward outside the tank (air flowing side) from the main flat portion 16d is possible. In this case, applying several core plate reinforcing structure disclosed in the first to tenth embodiment to both water flowing side and air flowing side of the main flat portion 16d can be done. Further, in the above-modified example, the cup shaped portion of the barring hole 16a is formed inside the tank (water flowing side), so it is preferable that the adhesive is potted on the inside of the tank (water flowing side) surface of the core plate 16 for simplifying a coating operation. Also, in the above embodiments, the case of arranging the tube 14 in only one row with respect to the cooling air flowing direction was explained. In addition to this, it is for granted that applying the present invention to such case that the tube 14 is arranged in two or more rows with respect to the cooling air flowing direction C is possible. Furthermore, in the above embodiments, one example that the present invention is applied to the car engine cooling radiator is explained. In addition to this, it is for granted that the present invention can be applied to the other heat exchanger such as a heater core.

Claims: A mechanically assembled type heat exchanger comprising: a tank (12, 13) provided with at least an inlet port (18) into which a fluid to be heat exchanged flows, or an outlet port (21) from which the heat exchanged fluid flows out; a core plate (16) connected to an opening surface (22) of said tank (12, 13); a sealing packing (25) disposed between said core plate (16) and said tank (12, 13); said core plate (16) having a hole (16a) thereon; a tube (14), an end portion of which is inserted into said hole (16a), and press fit to said core plate (16); a reinforcing member (16e, 16f, 16g, 16h, 16i, 16j) arranged at least around said hole (16a) for increasing a rigidity of said core plate (16), characterised in that an adhesive (24) is potted on said core plate (16) and seales the press fit portion of the end portion of said tube (14); said core plate (16) has a main flat portion (16d); a combined portion (16d') is formed on the substantially same plane as said main flat portion (16d) outside said hole (16a), and a rib (16g, 16h) is protruded from a plane of said main flat portion (16d) as said reinforcing member between said combined portion (16d') and said main flat portion (16d). A mechanically assembled type heat exchanger according to claim 1, wherein said tank (12, 13) is an upper tank (12) provided with said inlet port (18), and a lower tank (13) provided with said outlet port (21). A mechanically assembled type heat exchanger according to claim 1, wherein said hole (16a) is provided at a plurality of locations of said core plate (16). A mechanically assembled type heat exchanger according to claim 3, wherein a second rib (16i, 16j) is protruded from the plane of said main flat portion (16d) as said reinforcing member at a center region between said adjacent holes (16a). A mechanically assembled type heat exchanger according to claim 4, wherein said rib (16g, 16h) and said second rib (16i, 16j) intersect with each other orthogonally. A mechanically assembled type heat exchanger according to one of the preceeding claims, wherein said core plate (16) having a large number of holes (16a) thereon; and wherein the reinforcing member (26) is formed of an independent plate material of said core plate (16), and is connected to it at least around said hole (16a) integrally, for increasing a rigidity of said core plate (16). A mechanically assembled type heat exchanger according to claim 1 or 6, wherein, said hole (16a) is provided with a protrusion portion protruded from a plane of the main flat portion (16d) of said core plate (16). A mechanically assembled type heat exchanger according to claim 1 or 6, wherein said tube (14) is formed into a cross sectional oval shape; said oval tube (14) is arranged in such a manner that a main axis direction of said oval tube (14) is parallel to a flowing direction of a heat exchanged media flowing outside said tube (14), and said hole (16a) is in a oval shape corresponding to said oval tube. A mechanically assembled type heat exchanger according to claim 8, wherein a plate fin (15) is press fit to said oval tube (14) integrally. A mechanically assembled type heat exchanger according to claim 7, wherein said reinforcing member 26) is attached to said protrusion portion of said hole (16a).

Inventors: KATO SEIICHI, NAKASHIMA HISASHI, SUSA SUMIO, KATO, SEIICHI, NAKASHIMA, HISASHI, SUSA, SUMIO
Applicants: DENSO CORP, DENSO CORPORATION
Application year: 1997
Main classification: F28F9
IPC codes: F28F9