Lamination type heat exchanger with pipe joint

Abstract: A side refrigerant outlet passage (6) and a side refrigerant inlet passage (7) are provided between first and second protruding portions (42a, 42b) of a side plate (42) and an end plate (40), which are joined to one another. The side plate (42) has base portions (424b, 425b) protruding in an opposite direction of the end plate (40), and a pipe joint (8) including an outlet pipe (8d) and an inlet pipe (8e) is joined to the base portions (424b, 425b) of the side plate (42). Accordingly, a strength of joining portions between the side pate (42) and the pipe joint (8) is improved, and simultaneously processing cost of the pipe joint (8) is decreased.

Description: The present invention relates to a lamination type heat exchanger according to the preamble of claims 1 and 6. Such a lamination type heat exchanger is known from EP-A-703 425. This known lamination type heat exchanger comprises pairs of thin plates for forming fluid passages including an end plate. A side plate is joined to the end plate and has protruding portions, such that inlet and outlet passages are formed adjacent to one another in the same height on the side plate. On the protruding portions a pipe joint including a fluid inlet and a fluid outlet communicating with the inlet and outlet passages is joined. Further, outlet and inlet pipes are inserted into the fluid inlet and outlet. Recently, a refrigerant evaporator for an automotive air conditioner has been required to include a pipe joint that is disposed at a side central portion of a heat exchanging part for a refrigerant pipe arrangement. This pipe arrangement has high flexibility, because a pipe can be directly taken out from the side of the heat exchanging part, and the position where the pipe is taken out can be arbitrarily selected within the side region of the heat exchanging part. The applicant of the present invention proposed a lamination type evaporator. In the evaporator, an inlet tank portion for distributing refrigerant into refrigerant passages in a heat exchanging part is positioned at an end in refrigerant flow direction of the heat exchanging part, and an outlet tank portion for receiving the refrigerant that passes through the heat exchanging part is positioned at the other end in the refrigerant flow direction of the heat exchanging part. A side refrigerant inlet passage for conducting refrigerant into the inlet tank portion and a side refrigerant outlet passage into which refrigerant flows from the outlet tank portion are provided at a side of the heat exchanging part (at an end in a lamination direction of metallic thin plates). The side refrigerant inlet passage is connected to a refrigerant inlet portion of a pipe joint, while the side refrigerant outlet passage is connected to a refrigerant outlet portion of the pipe joint. Specifically, the side refrigerant inlet passage and the side refrigerant outlet passage are defined by an end plate and a side plate that are positioned at the side of the heat exchanging part (at the end in the lamination direction of the metallic thin plates). The pipe joint is joined to the side plate. In this known heat exchanger, however, when an external refrigerant pipe is connected to the pipe joint, force is externally applied to the joining (brazing) portion between the pipe joint and the side plate, thereby generating excessive stress in the joining portion. This excessive stress can decreas strength of the joining portion. The present invention has been made in view of the above problem. An object of the present invention is to improve strength against external force at a joining portion between a side plate and a pipe joint at low cost. This object is solved by the features cited in the characterising parts of claims 1 and 6. According to a first aspect of the present invention, a lamination type heat exchanger includes side outlet and inlet passages, which are provided between an end plate and first and second protruding portions of a side plate, and a pipe joint that includes a fluid outlet and a fluid inlet respectively communicating with the side outlet and inlet passages. The first and second protruding portions further have first and second base portions embossing from the first and second protruding portions toward an opposite side of the end plate in a lamination direction of metallic thin plates, and an end face of the pipe joint is joined to the first and second base portions. As a result, a joining area between the pipe joint and the side plate is secured, so that joining strength therebetween against external force is improved. In addition, because the base portions are formed on the side plate that is formed from a metallic thin plate, the base portions can be readily formed when the side plate is formed by pressing. On the other hand, the end face of the pipe joint can be made flat, so that the pipe joint can be readily formed by cold forging, resulting in low processing cost of the pipe joint. According to a second aspect of the present invention, a side plate joined to an end plate includes first, second, and third members. The first member has strength that is larger than those of the second and third members, and the second and third members respectively have first and second protruding portions for forming with the end plate a side outlet passage and a side inlet passage. Specifically, the strength of the first member is increased by increasing a thickness of the first member more than the second and third members. Otherwise, the first member is made of material having a strength that is larger than those of the second and third members. As a result, the joining strength between the pipe joint and the side plate is secured. The end face of the pipe joint can be made flat, so that the pipe joint is readily formed by cold forging, resulting in low processing cost of the pipe joint. Preferably, the pipe joint is composed of a joint body that is joined to the side plate, and outlet and inlet pipes, which are inserted into first and second through holes of the joint body. Accordingly, even if the outlet and inlet pipes have complicated configurations, the joint body separated from the pipes can be easily formed by cold forging. Other objects and features of the present invention will become more readily apparent from a better understanding of the preferred embodiments described below with reference to the following drawings. Fig. 1 is a plan view partially showing a side plate in a prototype formed by the inventors; Fig. 2 is a cross-sectional view taken along a II-II line in Fig. 1, showing the side plate and a pipe joint joined to the side plate; Fig. 3 is a front view showing an evaporator in a first preferred embodiment; Fig. 4 is a cross-sectional view partially showing the evaporator shown in Fig. 3; Fig. 5 is a plan view showing a side plate in the first embodiment; Fig. 6 is a partially enlarged view of the side plate shown in Fig. 5; Fig. 7 is a cross-sectional view taken along a VII-VII line in Fig. 6, showing the side plate and a pipe joint joined to the side plate; Fig. 8 is a plan view showing a side plate in a second preferred embodiment; Fig. 9 is a partially enlarged view of the side plate shown in Fig. 8; Fig. 10 is a cross-sectional view taken along a X-X line in Fig. 9, showing the side plate and a pipe joint joined to the side plate; Fig. 11 is a cross-sectional view showing a side plate and a pipe joint joined to the side plate, at a position corresponding to that taken along the VII-VII line in Fig. 6, according to a third preferred embodiment; Fig. 12A is a cross-sectional view for explaining a feature in the third embodiment; Fig. 12B is an enlarged view of a circled portion XIIB in Fig. 12A; Fig. 13A is a cross-sectional view for explaining the feature in the third embodiment; Fig. 13B is an enlarged view of a circled portion XIIIB in Fig. 13A; Fig. 14A is a cross-sectional view for explaining a feature in the third embodiment; Fig. 14B is an enlarged view of a circled portion XIVB in Fig. 14A; Fig. 15 is exploded perspective view showing a side plate and a pipe joint in a fourth preferred embodiment; Fig. 16 is a cross-sectional view showing a side plate and a pipe joint attached to the side plate in a modified embodiment; and Fig. 17 is a cross-sectional view showing a side plate and a pipe joint attached to the side plate in another modified embodiment. The inventors of the present invention manufactured a prototype joining structure shown in Figs. 1 and 2 and studied it. In Figs. 1 and 2, a side plate 42 is embossed to have protruding portions 42a, 42b protruding outwardly, thereby providing a side refrigerant outlet passage 6 and a side refrigerant inlet passage 7 therein. The side plate 42 further has sub-protruding portions 424, 425, which protrudes outwardly further from the protruding portions 42a, 42b at the central portion in the longitudinal direction of the side plate 42. Accordingly, refrigerant passage areas are enlarged, and pressure losses at generally right-angled corners of the passages are suppressed. On the other hand, a pipe joint 8 is composed of a joint body 8a that is a generally elliptically shaped block member, and refrigerant outlet and inlet pipes 8d, 8e that are respectively inserted into through holes 8b, 8c of the joint body 8a. Incidentally, the block member is significantly thicker than the side plate 42, a thickness of which is approximately 1 mm, to secure sufficient strength. Because of this, the side plate 42 is formed from an aluminum plate into a specific shape by pressing, and to the contrary, the joint body 8a is formed from an aluminum member by cold forging or the like. In this structure, joining deficiency between the refrigerant outlet and inlet pipes 8d, 8e and the side plate 42 easily causes refrigerant leakage. Therefore, the refrigerant outlet and inlet pipes 8b, 8e must be securely joined (brazed) to the side plate 42. In practice, the brazing of the joint body 8a and the refrigerant inlet and outlet pipes 8d, 8e to the side plate 42 is carried out using brazing filler metal for an aluminum clad member constituting the side plate 42. When the refrigerant outlet and inlet pipes 8d, 8e, and the joint body 8a are brazed on the identical surface, however, the brazing filler metal is attracted to a side of the joint body 8a that has a large area to be brazed by a surface tension thereof, resulting in shortage of the brazing filler metal for the joining portions at the side of the refrigerant outlet and inlet pipes 8d, 8e. As a result, brazing deficiency occurs at the side of the refrigerant outlet and inlet pipes 8d, 8e. Therefore, in the prototype structure shown in Figs. 1 and 2, the joint body 8a is formed with base portions 8k protruding toward the side plate side with a height of approximately 1.5 mm as joining faces (brazing faces) to the side plate 42. With this structure, the inventors tried to braze the joint body 8a to the side plate 42 in a state where the base portions 8k are brought to contact the side plate 24 by pressure. In Fig. 1, regions Y hatched with slant lines indicate the joining portions of the joint body 8a at the base portions 8k. According to this prototype structure, recess portions (joining face interception part) 8g are provided between the joining portions of the joint body 8a and the joining portions of the refrigerant outlet and inlet pipes 8d, 8e. The recess portions 8g prevent the brazing filler metal from moving from the side of the refrigerant outlet and inlet pipes 8d, 8e to the side of the joint body 8a, so that the brazing filler metal is secured for the refrigerant outlet and inlet pipes 8d, 8e to improve brazing performance. Simultaneously, a sufficient joining area resistible to external force is secured by the base portions 8k. In the prototype structure, however, it is necessary to form the complicated circular-like base portions 8k, which cannot easily be formed by cold forging. Therefore, the joint portion 8a is not formed only by cold forging, and cutting work must be carried out on the joint body 8a to form the base portions 8k, resulting in deterioration of workability and increased cost of the joint body 8a. Preferred embodiments of the present invention have been made to further improve these points. (First Embodiment) In a first preferred embodiment, the present invention is applied to a refrigerant evaporator 1 shown in Figs. 3 and 4 in a refrigerating cycle for an automotive air conditioner. The evaporator 1 receives low-temperature low-pressure gas-liquid two-phase refrigerant that is decompressed by a thermostatic expansion valve (decompressing device) that is not shown. As shown in Figs. 2 and 3, the evaporator 1 includes plural refrigerant passages 2 arranged in parallel, and a heat exchanging part 3 for exchanging heat between refrigerant (inside fluid) flowing in the refrigerant passages 2 and conditioning air flowing outside the refrigerant passages 2. The heat exchanging part 3 has a lamination structure composed of metallic thin plates 4. Each of the metallic thin plates 4 is formed from a both-surface clad member (thickness : approximately 0.6 mm) into a specific shape. The both-surface clad member is composed of an aluminum core member (No. A3000 family material), both surface of which are clad with brazing filler metal (No. A4000 family material). The metallic thin plates 4 forms plural pairs. The plural pairs are laminated with and joined to one another by brazing, thereby providing the plural refrigerant passages 2 extending in parallel with one another. The metallic thin plates 4 respectively have tank portions 4c, 4d with communication holes 4a, 4b on both ends thereof (on the upper and lower ends in Fig. 4). The refrigerant passages 2 communicate with one another through the tank portions 4c, 4d. Each of the tank portions 4c, 4d is a cup-like protruding portion protruding outwardly in the lamination direction of the metallic thin plates 4 (in the crosswise direction in Figs. 3 and 4). In this embodiment, the tank portions 4c at one side constitute an outlet side tank portion in which refrigerant gathers after passing through the refrigerant passages 2, while the tank portions 4d at the other side constitute an inlet tank portion from which refrigerant is distributed into the refrigerant passages 2. In the heat exchanging part 3, corrugated fins 5 are disposed between respective adjacent two of the refrigerant passages 2 at an outer surface side, and are joined thereto, thereby increasing a heat transfer area at an air side. Each of the corrugated fins 5 is formed into a specific shape from an aluminum bare member such as A3003 that is not clad with brazing filler metal. An end plate 40 is disposed at an end portion of the heat exchanging part 3 (at the right end portion in Fig. 4) in the lamination direction of the metallic thin plates 4, and a side plate 42 is joined to the end plate 40. Another end plate 41 is disposed at the other end portion (at the left end portion in Fig. 4) in the lamination direction described above, and another side plate 43 is joined to the end plate 41. Each of the plates 40-43 is composed of the both-surface clad member as well as the metallic thin plates 4, and has a thickness of, for instance, approximately 1 mm, which is thicker than that of the metallic thin plates 4, to have sufficient strength thereof. The end plate 40 has tank portions 40c, 40d with communication holes 40a, 40b at both ends thereof. The tank portions 40c, 40d are also shaped into cup-like protrusions protruding outwardly in the metallic thin plate lamination direction. The communication hole 40a of the tank portion 40c at one side communicates with the outlet side tank portion 4c of the metallic thin plates 4, while the communication hole 40b of the tank portion 40d at the other side communicates with the inlet side tank portion 4d. The side plate 43 at the left end portion in Figs. 3 and 4 enhances rigidity of the heat exchanging part 3 and simultaneously provides a refrigerant passage (not shown) with the end plate 41. The constitution of the refrigerant passages including this refrigerant passage is disclosed in JP-A-9-170850, and the detailed explanation is omitted. The side plate 42 at the right end portion in Figs. 3 and 4 is formed with first and second protruding portions 42a, 42b which protrude outwardly in the metallic thin plate lamination direction with rib-like shapes. The two protruding portions 42a, 42b are separated from one another at an approximately intermediate portion in the side plate longitudinal direction, and side refrigerant outlet and inlet passages 6 and 7 are provided in the spaces defined by the two protruding portions 42a, 42b and the end plate 40, respectively. The side refrigerant outlet passage 6 communicates with outlet portions (upper end portions in Fig. 4) 2a of the respective refrigerant passages 2 through the tank portion 40c and the outlet side tank portion 4c. The side refrigerant inlet passage 7 communicates with inlet portions (lower end portions in Fig. 4) 2b of the refrigerant passages 2 through the tank portion 40d and the inlet side tank portion 4d. Fig. 5 shows the side plate 42 from a side of a pipe joint 8 described below (from an outside), and Fig. 6 is a partially enlarged view of Fig. 5 and indicates the pipe joint 8 with two-dot chain lines. Fig. 7 is a cross-sectional view taken along a VII-VII line in Fig. 6. As shown in Fig. 5, the first and second protruding portions 42a, 42b of the side plate 42 are respectively divided into several (six in this embodiment) parts, and protrudes from a reference joining face (brazing face) 420 in parallel with the side plate longitudinal direction. The reference joining face (brazing face) 420 is a face that is to be brazed to the end plate 40, and corresponds to the face at the paper space back side in Fig. 5. Reinforcement ribs 421, 422 are provided respectively between the divided parts of the first and second protruding portions 42a, 42b to serve as joining faces that are to be joined to the end plate 40. The top portions of the reinforcement ribs 421, 422 protrude in an opposite direction (in a back side direction of the paper space in Fig. 5) with respect to the top portions of the protruding portions 42a, 42b. The top portions of the reinforcement ribs 421, 422 are coplanar with the reference joining face 420 of the side plate 42. As understood from the constitution described above, the side refrigerant outlet passage 6 and the side refrigerant inlet passage 7 are respectively composed of parallel passages defined by the divided parts of the protruding portions 42a, 42b, and are partitioned from one another by a partitioning joining face 423 that extends entirely in a width direction of the side plate 42 at the intermediate portion in the side plate longitudinal direction. The partitioning joining face 423 is also coplanar with the reference joining face 420. Further, first and second sub-protruding portions 424, 425 are integrally formed at upper and lower sides of the partitioning joining face 423 to protrude outwardly in the lamination direction (in the right direction in Fig. 4) more than the top portions (protruding end faces) of the first and second protruding portions 42a, 42b. As shown in Fig. 4, an inside space of the first (upper side) sub-protruding portion 424 communicates with a downstream side end portion of the side refrigerant outlet passage 6 defined by the protruding portion 42a. An inside space of the second (lower side) sub-protruding portion 425 communicates with an upstream side end portion of the side refrigerant inlet passage 7 defined by the protruding portion 42b. The first and second sub-protruding portions 424, 425 have circular opening portions 424a, 425a, respectively, at protruding end faces thereof for connecting inside and outside spaces thereof. The first and second sub-protruding portions 424, 425 further have base portions 424b, 425b that extend at relatively larger areas at outer circumference sides of the opening portions 424a, 425a on the protruding end faces. The base portions 424b, 425b are embossed by pressing. The base portions 424b, 425b have generally arc-like rib shapes extending along the outer circumferences of the opening portions 424a, 425a, and protrude toward a side of the pipe joint 8 to contact an end face of a joint body 8a. The joint body 8a of the pipe joint 8 is formed from a No. A6000 family aluminum bare member into a generally elliptical block body by cold forging. Two through holes 8b, 8c are formed to passing through the joint body 8a in the thickness direction (in the crosswise direction in Fig. 7) of the block body. Refrigerant outlet and inlet pipes 8d, 8e are respectively inserted into the through holes 8b, 8c, and are retained by the joint body 8a. Both pipes 8d, 8e are formed from No. A6000 family aluminum bare members as well. In this embodiment, the pipes 8d, 8e are respectively formed with grooves 8h, 8i for holding O-rings 8f, 8g therein at external protruding end portions thereof. The O-rings 8f, 8g are for sealing connecting portions with counter pipes. The grooves 8h, 8i, however, complicate the shapes of the pipes 8d, 8e, and accordingly, it is difficult to integrally form the pipes 8d, 8e with the joint body 8a by cold forging or the like. Therefore, the pipes 8d, 8e are separately formed from the joint body 8a. The joint body 8a has two holes 8j for attachment. The joint body 8a is, as shown in Figs. 4, 6, and 7, disposed on the two sub-protruding portions 424, 425. Specifically, the flat end face of the joint body 8a is brought to contact and is joined (brazed) to the base portions 424b, 425b of the sub-protruding portions 424, 425 in a state where the refrigerant outlet pipe 8d communicates with the opening portion 424a of the sub-protruding portion 424 and the refrigerant inlet pipe 8e communicates with the opening portion 425a of the sub-protruding portion 425, respectively. The front end portions of the pipes 8d, 8e are brought to contact and joined (brazed) to peripheral portions of the opening portions 424a, 425a of the sub-protruding portions 424, 425. Thus, the joint body 8a, and the pipes 8d, 8e are respectively integrally brazed to the side plate 42. Therefore, the pipes 8d, 8e need not be brazed to the joint body 8a. In practice, however, when the evaporator 2 is integrally brazed, brazing filler metal invades into clearances between the through holes 8b, 8c and the pipes 8d, 8e due to surface tension thereof. The pipes 8d, 8e consequently are brazed to the joint body 8a. On the other hand, the refrigerant inlet pipe 8e of the pipe joint 8 is connected to an outlet side refrigerant pipe of the expansion valve that is not shown. The refrigerant outlet pipe 8d is connected to a suction pipe of the compressor that is not shown. The first and second sub-protruding portions 424, 425 enlarge passage areas at approximately right-angled corners provided at portions immediately before and after the pipe joint 8, thereby suppressing an increase in pressure loss. Next, a manufacturing method of the refrigerant evaporator 1 in this embodiment will be briefly explained. The evaporator 1 is temporarily assembled in the state shown in Fig. 3, and after that is transferred into a brazing furnace while keeping the temporarily assembled state using a specific jig. Then, the temporarily assembled member is heated up to a melting point of brazing filler metal for the aluminum clad members, thereby integrally brazing respective parts of the evaporator 1. According to the constitution described above in the first embodiment, because the base portions 424b, 425b composed of rib-like protrusions are formed, joining portions (regions Y1 hatched with slant lines in Fig. 6) at the side of the joint body 8a are separated from the joining portions at the side of the refrigerant outlet and inlet pipes 8d, 8e by steps as joining face interception parts 424c that have heights approximately equal to the thickness (for instance, approximately 1 mm) of the side plate 42. Accordingly, brazing filler metal is prevented from moving from the joining portions at the sides of the refrigerant outlet and inlet pipes 8d, 8e toward the joining portions Y1 at the side of the joint body 8a, so that brazing filler metal can be secured at the joining portions at the sides of the outlet and inlet pipes 8d, 8e. As a result, the brazing property at the sides of the refrigerant outlet and inlet pipes 8d, 8e are improved, and consequently refrigerant leakage does not occur due to the brazing deficiency at the sides of the refrigerant outlet and inlet pipes 8d, 8e. Simultaneously, the joining portions Y1 shown in Fig. 6 can have relatively large areas due to the base portions 424b, 425b. Accordingly, even if external force is applied to the pipe joint 8 when external pipes are connected to the refrigerant outlet and inlet pipes 8d, 8e, the pipe joint 8 can have strength resistible to the external force. In addition, because the base portions 424b, 425b are formed on the side plate 42 that is formed from the metallic (aluminum) thin plate having a thickness of approximately 1 mm, the base portions 424b, 425b can be formed when the side plate 42 is formed by pressing. Comparing with the case where the base portions 8f are formed on the block body 8a, it is not necessary to perform cutting work after cold forging, and the end face of the joint body 8a is flat. Therefore, the joint body 8a can be formed only by cold forging, resulting in improved workability and low processing cost of the pipe joint 8. (Second Embodiment) A joining structure in a second preferred embodiment will be explained referring to Figs. 8 to 10. In the first embodiment, the flat end face of the joint body 8a is joined to the base portions 424b, 425b of the side plate 42. In addition to that, in the second embodiment, protruding portions 424d, 425d are formed on the side plate 42 at the outer circumference sides of the base portions 424b, 425b to protrude outwardly (toward the side of the pipe joint 8) more than the base portions 424b, 425b. The protruding portions 424d, 425d have arc-like shapes along the generally semicircular side surfaces on both end portions of the joint body 8a in the longitudinal direction, and cover (contact) parts of the side surfaces on the both end portions of the joint body 8a. Accordingly, the joining area between the joint body 8a and the side plate 42 is increased, resulting in further improved joining strength. Incidentally, external force is generally applied to the pipe joint 8 in the crosswise direction in Fig. 9 (in the side plate width direction). Therefore, as shown in Fig. 9, it is effective for improving the joining strength in the crosswise direction to dispose the base portions 424b, 425b at the right and left both sides of the first and second sub-protruding portions 424, 425, respectively. The right and left base portions 424b, 424b of the first sub-protruding portion 424 and the right and left base portions 425b, 425b of the second sub-protruding portion 425 may be respectively integrated as continuing base portions as indicated by two-dot chain lines a, b shown in Fig. 9. (Third Embodiment) A joining structure in a third preferred embodiment will be explained referring to Fig. 11 which corresponds to a cross-section taken along a VII-VII line in Fig. 6. In the third embodiment, the base portions 424b, 425b are formed to protrude from the first and second sub-protruding portions 424, 425 of the side plate 42, and at the same time, base portions 8k are formed at the front end face of the joint body 8a to protrude toward the side of the base portions 424b, 425b and to be joined to the base portions 424b, 425b. According to the third embodiment described above, because both the side plate 42 and the joint body 8a have the protruding portions 424d, 425d, and 8k, respectively, protruding heights H 1 , H 2 of the base portions 424b, 425b, and 8k can be decreased as follows. That is, in a structure (the prototype structure of Fig. 2) shown in Figs. 12A and 12B, it is necessary for the base portion 8f to have the protruding height H 2 of approximately 1.5 mm. To the contrary, according to the third embodiment, as shown in Figs. 13A and 13B, the protruding height H 2 of the respective base portions 8k can be decreased to approximately 0.75 mm that is an approximately half of that shown in Figs. 12A and 12B. Further, in the first embodiment shown in Figs. 14A and 14B, it is necessary for the base portions 424b, 425b to have the protruding height H 1 of approximately 1.5 mm. To the contrary, according to the third embodiment, the protruding height H 1 of the base portions 424b, 425b can be decreased to approximately 0.75 mm that is an approximately half of that shown in Figs. 14A and 14B. Thus, the protruding height H 1 of the base portions 424b, 425b at the side plate side and the protruding height H 2 of the base portions 8k at the joint body side can be decreased to half of their dimensions, respectively. This makes it possible to form base portions 8k of the joint body 8a by cold forging. Further, concerning the side plate 42, a plastic deformation amount (processing degree) of the plate as a whole is decreased due to the decrease in the protruding height H 1 of the respective base portions 424b, 425b, resulting in improvement of workability of the side plate 42 at pressing. (Fourth Embodiment) A joining structure in a fourth preferred embodiment will be explained referring to Fig. 15. In the fourth embodiment, the side plate 42 is divided into first, second, and third members 42A, 42B, 42C. The first member 42A is to be joined to the pipe joint 8, the second member 42B has the protruding portion 42a for defining the side refrigerant outlet passage 6, and the third member 42C has the protruding portion 42b for defining the side refrigerant inlet passage 7. Because the first member 42A is joined to the pipe joint 8, the strength of the first member 42A needs to be enhanced. On the other hand, the second and third members 42B, 42C are for forming the refrigerant passages 6, 7, and do not directly receive external force. Therefore, the first member 42A has a thickness (for instance, approximately 1.2 mm) that is larger than that (for instance, approximately 1 mm) of the second and third members 42B, 42C. As a result, the first member 42A has a sufficient joining strength to the pipe joint 8. Instead of increasing the thickness of the first member 42A more than that of the second and third members 42B, 42C, the first member 42A may be made of high strength material having a strength more than that of the second and third members 42B, 42C. For instance, BA10PC-O can be used as the high strength material for the first member 42A, while BA10PC-H14 can be used as material, which has strength smaller than that of the first member 42A, for the second and third members 42B, 42C. According to the fourth embodiment, the strength of the first member 42A is enhanced more than that of the second and third members 42B, 42C by appropriately selecting at least one of the thickness and the material thereof. As a result, the joining strength (breakage strength) between the first member 42A and the pipe joint 8 is improved. Accordingly, it is not always necessary to form the base portions 424b, 425b and the protruding portions 424d, 425d as in the first and second embodiments. However, if necessary, the base portions 424b, 425b, and the protruding portions 424d, 425d in the first and second embodiments can be combined with the constitution in the fourth embodiment. Further, in the fourth embodiment, the countermeasure of increasing the thickness of the first member 42A more than that of the second and third members 42B, 42C may be combined with the countermeasure of forming the first member 42A from the material having the strength larger than that of the second and third members 42B, 42C. While the present invention has been shown and described with reference to the foregoing preferred embodiments, it will be apparent to those skilled in the art that changes in form and detail may be made therein without departing from the scope of the invention as defined in the appended claims. For instance, in the first to third embodiments described above, as shown in Figs. 7, 10, and 11, the outlet and inlet pipes 8d, 8e of the pipe joint 8 do not protrude into the side refrigerant outlet and inlet passages 6, 7; however, as shown in Fig. 16, the outlet and inlet pipes 8d, 8e may be protrude into the side refrigerant outlet and inlet passages 6, 7, respectively. Further, the protruding portions of the outlet and inlet pipes 8d, 8e may be caulked as shown in Fig. 17. Accordingly, the outlet and inlet pipes 8d, 8e can be more steadily fixed to the side plate 42. In the first to fourth embodiments, the pipe joint 8 is composed of the joint body 8a, and the outlet and inlet pipes 8d, 8e, which are integrated with the joint body 8a by being inserted into the through holes 8b, 8c of the joint body 8a. However, when the outlet and inlet pipes 8d, 8e have simple configurations, the outlet and inlet pipes 8d, 8e may be integrally formed with the joint body 8a by cold forging using aluminum or the like. It is apparent that the present invention can be applied to such a pipe joint 8.

Claims: A lamination type heat exchanger comprising: a plurality of pairs of metallic thin plates (4, 40, 41) laminated with one another for forming a plurality of fluid passages (2) therein, in which an inside fluid flows for exchanging heat with an outside fluid flowing outside the plurality of fluid passages (2), the plurality of fluid passages (2) respectively having inlet and outlet portions (2a, 2b) of the inside fluid, the plurality of pairs of metallic thin plates (4, 40, 41) including an end plate (40) that is disposed at an end in a lamination direction of the plurality of pairs of metallic thin plates (4, 40, 41); a side plate (42) joined to the end plate (40), and having first and second protruding portions (42a, 42b) for forming a side outlet passage (6) and a side inlet passage (7) with the end plate (40), the side outlet passage (6) communicating with the outlet portions (2a) of the plurality of fluid passages (2), the side inlet passage (7) communicating with the inlet portions (2b) of the plurality of fluid passages (2), the first and second protruding portions (42a, 42b) having first and second base portions (424b, 425b) embossing from the first and second protruding portions toward an opposite side of the end plate (40) in the lamination direction; and a pipe joint (8) including a fluid outlet that communicates with the side outlet passage (6) and a fluid inlet that communicates with the side inlet passage (7), and having an end face that is joined to the first and second base portions (424b, 425b) of the side plate (42); wherein the first and second protruding portions (42a, 42b) of the side plate (42) have first and second opening portions (424a, 425a) for communicating with the fluid outlet and the fluid inlet of the pipe joint (8), and first and second peripheral portions respectively surround the first and second opening portions (424a, 425a); and wherein the pipe joint (8) comprises a joint body (8a) joined to the first and second base portions (424b, 425b) of the side plate (42) and having first and second through holes (8b, 8c); an outlet pipe (8d) having the fluid outlet therein, inserted into the first through hole (8b) of the joint body (8a), the pipe is brought to contact and joined to the first peripheral portion of the side plate (42), and an inlet pipe (8e) having the fluid inlet therein, inserted into the second through hole (8c) of the joint body (8a), the pipe is brought to contact and joined to the second peripheral portion of the side plate (42) characterised in that , said peripheral portions are a part of sub-protuding portions (424, 425), which surround said opening portions (424a, 425a), and said joint body (8a) has a surface contacting each side surface of the first and second base portions (424b, 425b). The lamination type heat exchanger of claim 1, wherein at least one of the first and second protruding portions (42a, 42b) of the side plate (42) has a secondary protruding portion (424d, 425d) protruding more than the first and second base portions (424b, 425b) to contact a side face of the pipe joint (8). The lamination type heat exchanger of claim 1, wherein the end face of the pipe joint (8) is flat. The lamination type heat exchanger of claim 1, wherein: the end face of the pipe joint (8) has a pipe joint base portion (8k) partially protruding from the end face toward the side plate (42); and the pipe joint base portion (8k) is joined to the first and second base portions (424b, 425b) of the side plate (42). The lamination type heat exchanger of claim 1, wherein: the first and second base portions (424b, 425b) are respectively provided around the first and second peripheral portions; and the first and second base portions (424b, 425b) protrude in the opposite direction of the end plate (40) more than the first and second peripheral portions, respectively. A lamination type heat exchanger comprising: a plurality of pairs of metallic thin plates (4, 40, 41) laminated with one another for forming a plurality of fluid passages (2) therein, in which an inside fluid flows for exchanging heat with an outside fluid flowing outside the plurality of fluid passages (2), the plurality of fluid passages (2) respectively having inlet and outlet portions (2a, 2b) for the inside fluid, the plurality of pairs of metallic thin plates (4, 40, 41) including an end plate (40) that is disposed at an end in a lamination direction of the plurality of pairs of metallic thin plates (4, 40, 41); a side plate (42) joined to the end plate (40) and including first and second protruding portions (42a, 42b) for forming with the end plate (40) a side outlet passage (6) that communicates with the outlet portions (2a) of the plurality of fluid passages (2), and for forming with the end plate a side inlet passage (7) that communicates with the inlet portions (2b) of the plurality of fluid passages (2) respectively, and a pipe joint (8), the pipe joint including a fluid outlet (8d) that communicates with the side outlet passage (6) and a fluid inlet (8e) that communicates with the side inlet passage (7), characterised in that said side-plate (42) includes first, second, and third members (42A, 42B, 42C), the first member (42A) having a strength that is larger than those of the second and third members, the second member (42B) having the first protruding portion (42a), and the third member (42C) having the second protruding portion (42b); and the pipe joint (8) is joined to the first member (42A) of the side plate (42). The lamination type heat exchanger of claim 6, wherein the first member has a thickness that is larger than those of the second and third members. The lamination type heat exchanger of claim 6, wherein the first member is made of a material having a strength that is larger than those of the second and third members. The lamination type heat exchanger of claim 6, wherein the pipe joint (8) comprising: a joint body (8a) joined to the first member (42A) of the side plate (42) and having first and second through holes (8b, 8c); an outlet pipe (8d) having the fluid outlet therein and inserted into the first through hole of the joint body; and an inlet pipe (8e) having the fluid inlet therein and inserted into the second through hole of the joint body. The lamination type heat exchanger according to claim 1, wherein the first and second protruding portions (42a, 42b) form with the end plate (40) a side outlet passage (6) and a side inlet passage (7) respectively communicating with the outlet and inlet portions (2a, 2b) of the plurality of fluid passages (2), the first and second protruding portions (42a, 42b) having first and second opening portions; and wherein the pipe joint (8) includes joint body (8a) that has first and second through holes (8b, 8c) therein and is joined to a first joining region of the side plate (42), and outlet and inlet pipes (8d, 8e) respectively inserted into the first and second through holes (8b, 8c) to protrude with their front end portions from the first and second through holes (8b, 8c) at ends thereof and to communicate with the first and second opening portions of the side plate (42), the outlet and inlet pipes (8d, 8e) being joined to second and third joining regions of the first and second protruding portions (42a, 42b) of the side plate (42), the second and third joining regions being non-coplanar with the first joining region. The lamination type heat exchanger of claim 10, wherein: the first joining region includes a first part that is provided on the first protruding portion (42a) around the second joining region, and a second part that is provided on the second protruding portion (42b) around the third joining region; and the first and second parts of the first joining region protrude in an opposite direction of the end plate more than the second and third joining regions. The lamination type heat exchanger of claim 10, wherein the outlet and inlet pipes (8d, 8e) may protrude into the side refrigerant outlet and inlet passages (6, 7), respectively. The lamination type heat exchanger of claim 12, wherein the outlet and inlet pipes (8d, 8e), which may protrude into the side refrigerant outlet and inlet passages (6, 7), respectively, are caulked.

Inventors: AIKAWA YASUKAZU, NAKAMURA TOMOHIKO, AIKAWA, YASUKAZU, NAKAMURA, TOMOHIKO, Aikawa, Yasukazu c/o Denso Corporation, Nakamura, Tomohiko c/o Denso Corporation
Applicants: DENSO CORP, DENSO CORPORATION
Application year: 1999
Main classification: F28F9
IPC codes: F28F9, F28F3, F28D1