WO2007049438A1 - Heat exchanger and process for manufacturing the same - Google Patents

Abstract

Tubes (5), seat plates (7,8), plate fins (6) and tanks (9,10) are fitted together and mechanically bonded together with tolerance. Before fixing of tank (9) to the seat plates (7,8), the core consisting of tubes (5), seat plates (7,8) and plate fins (6) is subjected to main firing, attaining complete curing of semicured coating layer (18).

Description

 Specification

 Heat exchanger and manufacturing method thereof

 Technical field

 The present invention relates to a heat exchanger used in a cooling system of a fuel cell vehicle, for example, and a method for manufacturing the same.

 Background art

 [0002] For example, in a cooling system of an FCEV vehicle (luelce 11 electric vehicle), which is a fuel cell vehicle equipped with a fuel cell as a drive source, there are many conductive members such as electrodes inside the fuel cell. From the viewpoint of prevention, it is necessary to make the conductivity of the refrigerant low, and pure water with extremely low conductivity is used. In addition, as a component of the cooling system, stainless steel is used as much as possible in order not to deteriorate the electrical conductivity !, and the heat exchanger uses aluminum to reduce the weight and size.

 However, when the heat exchanger is formed of aluminum, aluminum may be corroded by pure water, or the corroded aluminum metal may be mixed into pure water and the pure water conductivity may be deteriorated. In order to prevent this, as disclosed in JP 2001-167782, a thermosetting organic resin (phenolic, acrylic, epoxy) is used on the inner surface of a tube and tank member that serve as a flow path for pure water. A technology for forming a (phenolic) coating layer has been devised.

 [0004] As shown in Fig. 7, this coating layer is formed after the assembly process Sl for assembling the core, the flux application process S2 for applying flux, the brazing process S3 for brazing, and the cleaning process S4 for removing flux. Performed in coating step S5. In the coating step S6, the coating liquid is applied to the inner surfaces of the tube and tank member. In the next process, the upright drying step S8 and the horizontal drying step S9, the core is dried upright or horizontally, and finally the coating solution is heated in the baking step S10 to bake the coating agent on the inner surface. .

 Disclosure of the invention

[0005] By the way, heat exchange ^^ produced by this method uses Nocolox flux. In view of brazing, therefore, firing brazing at high temperature (500-600 ° C) is necessary, and in addition, in order to cause poor conductivity of the fuel cell coolant due to residual flux, it is important A lux cleaning process is required, and an increase in production costs is inevitable. For example, in the cleaning process S6, it takes about a week to put pure into the core and melt the flux.

 [0006] Therefore, the present invention eliminates the flux cleaning step by using brazing, greatly reduces production man-hours, prevents deterioration of pure purity, and improves the sealing performance between the tube and the seat plate. The purpose is to provide exchanges and methods for their production.

 One aspect of the present invention is a heat exchanger, in which a plurality of tubes each having at least an inner surface formed with a semi-cured coating layer and both end portions of the tubes are inserted into the plurality of tubes. A seat plate on which at least a semi-cured coating layer is formed on the inner surface, and a plurality of plate fins that are inserted into the tube and arranged at predetermined intervals in the longitudinal direction of the tube. A tank attached to the seat plate and having a completely hardened coating layer formed on the inner surface, and the tube, the seat plate, the plate fin and the tank are mechanically coupled with each other by fitting tolerances. In addition, the semi-cured coating layer is completely cured in the gap between the tube and the seat plate and in the gap between the tube and the plate fin. Is characterized in that the formed.

 [0008] Another aspect of the present invention is a method of manufacturing a heat exchanger, comprising: applying a coating liquid to at least the inner surface of a tube and the inner surface of a seat plate, drying and semi-curing; and a plurality of the tubes A step of inserting and arranging one end side portion of the one seat plate at a predetermined interval and a plate fin formed with a plurality of tube insertion holes inserted in the tube and extending in the longitudinal direction of the tube. A step of arranging a plurality at predetermined intervals, a step of inserting and arranging the other seating plate on the other end side of the tube, and a step of subjecting the tube, the seating plate, and the core made of plate fins to main firing. And a step of applying a coating liquid on the inner surface of the seat plate after the main baking and drying and completely hardening the seat plate, and forcing the tank.

 Brief Description of Drawings

FIG. 1 is a system diagram of a cooling system for an electric vehicle equipped with a fuel cell. FIG. 2 is a perspective view of a heat exchanger according to the present embodiment.

 FIG. 3 is an exploded perspective view of the heat exchanger according to the present embodiment.

 [FIG. 4] FIG. 4 (a) is an enlarged cross-sectional view of a main part showing a state where a tube is inserted and arranged on one seat plate, and FIG. 4 (b) is an enlarged cross-sectional view of a main part showing a state where a plate fin is inserted and arranged. is there.

 FIG. 5 is an enlarged cross-sectional view of a main part showing a state in which a punch is pushed into a tip portion of a tube projecting to the inner surface side of the seat plate to force the tube and the seat plate.

 [Fig. 6] Fig. 6 (a) is an enlarged cross-sectional view of the main part showing a state in which the core is fully fired, and Fig. 6 (b) is an enlarged cross-sectional view of the main part showing a state in which the tank is attached to the seat plate by force. .

 FIG. 7 is a flowchart showing a manufacturing process of a conventional heat exchanger.

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

 [0011] First, the FCEV cooling system using the heat exchanger of the present embodiment will be briefly described.

 [0012] "Schematic configuration of FCEV cooling system"

 Figure 1 is a cooling system diagram of an electric vehicle equipped with a fuel cell. Use a fuel cell as the drive source! / Some fuel cell vehicles generate heat most efficiently by maintaining the temperature of the fuel cell at about 80 [° C].冷却 Cool the fuel cell by circulating the refrigerant like so! / Speak.

In this cooling system 1, when the refrigerant that cools the heated fuel cell flows through the flow path formed in the fuel cell main body 2, it is sent to the heat exchanger 4 by the pump 3, and the fuel cell The refrigerant heated in the main body 2 is cooled by the heat exchanger 4. Then, the cooled refrigerant is sent again to the fuel cell main body 2 and is cooled down to keep the heated fuel cell at a predetermined temperature. As the refrigerant circulating in such a path, for example, pure water with low conductivity or a mixture of pure water and ethylene glycol as an antifreezing agent is used. This is because the fuel cell body 2 is provided with an electrode that is made of conductive material, so if the refrigerant circulating inside it has conductivity, the reaction between hydrogen and oxygen will be adversely affected. Because. [0014] "Schematic configuration of heat exchanger"

 As shown in FIGS. 2 and 3, the heat exchanger 4 of the present embodiment is arranged with a plurality of tubes 5 and a plurality of tubes 5 inserted into the tubes 5 at predetermined intervals in the longitudinal direction of the tubes 5. The plate fins 6 and both ends of the tubes 5 are inserted, and the plurality of tubes 5 are arranged at predetermined intervals. The seat plates 7 and 8 are arranged on the seat plates 7 and 8, and the tanks 9 and 10 are attached by force. And sealing members 11 and 12 for sealing between the seat plates 7 and 8 and the tanks 9 and 10

[0015] The tube 5, the plate fin 6, and the seat plates 7, 8 are all made of aluminum for the purpose of reducing the weight and size. The tube ₅ is formed, for example, as a cylindrical body having a circular cross section, and pure water as circulating water circulates therein. On the inner surface of the tube 5, as will be described later, a coating layer formed by applying an epoxy thermosetting coating liquid and drying and semi-curing is formed.

 [0016] The plate fin 6 functions as a cooling fin that promotes heat exchange between the pure water flowing in the tube 5 and the ambient air, and is formed as a rectangular plate. The plate fin 6 is formed with a tube insertion hole 13 into which each tube 5 is inserted. The tube insertion hole 13 is mechanical so that it does not slip off after the plate fin 6 is placed at a predetermined position with respect to the tube 5 due to the fitting tolerance between the inner diameter dimension and the outer diameter dimension of the tube 5. Dimensional relationship that is combined with

 The seat plates 7 and 8 are formed with tube insertion arrangement holes 14 and 15 for inserting and arranging a plurality of tubes 5 at predetermined intervals. The tube insertion holes 14 and 15 do not fall off after inserting both ends of the tube 5 due to the fitting tolerance between the inner diameter of the tube and the outer diameter of the tube 5, similar to the tube insertion hole 13. Dimensional relationship that is mechanically coupled to On the inner surfaces of the seat plates 7 and 8, as with the tube 5, a coating layer is formed by applying an epoxy thermosetting coating liquid and drying and semi-curing it.

[0018] Refrigerant introduction and discharge pipes 16, 17 for supplying pure water to the tubes 5 are attached to the tanks 9, 10. As will be described later, a coating layer is formed on the inner surfaces of the tanks 9 and 10 by applying an epoxy-based thermosetting coating solution and drying it completely. It is. The tanks 9 and 10 are formed of carbon fiber reinforced resin for the purpose of, for example, further lightening weight.

[0019] The seal members 11 and 12 seal between the seat plates 7 and 8 and the tanks 9 and 10, for example, EPD

Formed by M (ethylene propylene terpolymer)!

In the heat exchanger 4 configured as described above, pure water introduced into the tank 10 from one refrigerant introduction / discharge pipe 17 flows through each tube 5, and the core flows in the process of flowing through each tube 5. After heat exchange with the air passing through the tank, it joins the other tank 9 and is discharged from the other refrigerant introduction / discharge pipe 16, so that the fuel cell body 2 is maintained at an appropriate temperature. Yes.

 [0021] The heat exchanger according to the present embodiment includes a plurality of tubes each having at least an inner surface formed with a semi-cured coating layer, and both end portions of the tubes are inserted into the tubes at a predetermined interval. A seat plate on which at least a semi-cured coating layer is formed on the inner surface, a plurality of plate fins inserted into the tube and arranged at predetermined intervals in the longitudinal direction of the tube, and the seat A tank attached to the plate and having a completely hardened coating layer formed on the inner surface, the tube, the seat plate, the plate fin and the tank are mechanically coupled with each other through a fitting tolerance. The semi-cured coating layer is completely cured in the gap between the tube and the seat plate and between the tube and the plate fin to form a seal. To, Ru.

 [0022] Therefore, according to this heat exchanger, the sealing performance between the tube and the seat plate and between the tube and the plate fin can be enhanced, and brazing can be eliminated, thereby improving the heat exchange productivity. Can be made.

 [0023] "Method for manufacturing heat exchanger"

Next, a method for manufacturing the heat exchanger 4 described above will be described. First, the coating liquid is applied to the inner and outer surfaces of the tube 5 and the inner surfaces of the seat plates 7 and 8 and dried to be semi-cured. An epoxy thermosetting coating liquid is used as the coating liquid. Once the coating solution is applied, it is dried at a temperature of about 80 ° C or less and semi-cured. As a result, a precoated coating layer 18 is formed on the inner and outer surfaces of the tube 5 and the inner surfaces of the seat plates 7 and 8. [0024] Next, a step of inserting and arranging one end side portion of one of the plurality of tubes 5 on one seat plate 7 at a predetermined interval is performed. That is, as shown in FIG. 4 (a), one end side portion of the tube 5 is inserted into each of the tube insertion arrangement holes 14 formed in the seat plate 7. As a result, the tube 5 and the seat plates 7 and 8 are mechanically coupled and fixed by fitting tolerances of the outer diameter of the tube 5 and the inner diameter of the tube insertion hole 14.

 Next, a plurality of plate fins 6 are inserted from the other end side of the tube 5 fixed to the seat plate 7, and a plurality of plate fins 6 are arranged at predetermined intervals in the longitudinal direction of the tube 5. That is, as shown in FIG. 4B, the tube insertion hole 13 formed in the plate fin 6 is passed through the other end side portion of the tube 5 fixed to the seat plate 7. Then, the plate fin 6 is slid to the predetermined height position of the tube 5. By repeating this process, a plurality of plate fins 6 are arranged at predetermined intervals in the longitudinal direction of the tube 5.

 Next, as shown in FIG. 5, a punch 19 is pushed into the tip end portion (refrigerant flow hole) of the tube 5 protruding from the tube insertion arrangement hole 14 to the inner surface of the seat plate 7, so that the tube 5 Push and widen the tip side. Thereby, the coupling force between the tube 5 and the seat plate 7 is increased.

 [0027] Next, a process of inserting and arranging the other seat plate 8 in the other end side portion of the tube 5 is performed.

 Since this step is the same as the step of inserting and arranging one seat plate 7 on one end side of the tube 5 described above, the description thereof is omitted.

 Next, a step of subjecting the core composed of the tube 5, the seat plates 7, 8 and the plate fin 6 assembled in this way to the main firing is performed. In the main firing, the core is heated with a heat of about 120 ° C or higher by a heating means such as a heater. Then, the semi-cured coating layer 18 is melted by heat as shown in FIG. 6 (a), and the gap between the tube insertion holes 14, 15 and the tube 5 and between the tube insertion hole 13 and the tube 5 are melted. After entering each of the gaps, it is fluidized and completely cured.

 [0029] Next, as shown in FIG. 6 (b), a tank is formed by forming a coating layer 18 on the inner surface of the post-fired seat plates 7, 8 by applying a coating liquid on the inner surface and drying it completely. Enforce 9 and 10. This completes the heat exchange 4 that is assembled by mechanical connection without brazing.

[0030] As described above, according to the present embodiment, the coating liquid is applied to the inner surface and dried. Thus, the semi-cured coating layer 18 is formed, so that the pre-coated tube 5 and the seat plates 7 and 8 and the coating layer 18 which is completely cured by applying the coating liquid on the inner surface and drying are formed. Brazing can be eliminated by mechanically connecting the tanks 9 and 10 and the plate fins 6 with the fitting tolerances. Therefore, according to the present embodiment, the flux application process and the flux cleaning process for removing the flux can be eliminated, and the production man-hour can be greatly reduced.

 [0031] Further, according to the present embodiment, since the core including the tube 5, the seat plates 7, 8 and the plate fin 6 is finally fired, the pre-coated semi-cured coating layer 18 is melted and the tube is melted. It is possible to seal the gap between the tube 5 and the seat plates 7 and 8 and to prevent the deterioration of the pure purity flowing through the heat exchanger 4.

 [0032] Further, according to the method of the present invention, the tube 5, the seat plates 7, 8 and the plate fins 6 are formed and the core is formed, and then the core is fully baked to apply the coating liquid to the inner surface. The dried and semi-cured coating layer 18 is melted by the heat, and the coating liquid enters the gap between the tube 5 and the seat plates 7 and 8, and is completely cured. Therefore, according to the method of the present invention, the sealing performance between the tube 5 and the seat plates 7 and 8 can be enhanced, and the pure purity can be prevented from being deteriorated.

 Industrial applicability

[0033] According to the present invention, a coating layer is formed by applying a coating liquid on the inner surface and drying and semi-curing it. In other words, the precoated tube and seat plate are coated, and the coating liquid is applied to the inner surface and dried. Brazing can be eliminated by mechanically coupling and assembling the tank in which the completely hardened coating layer is formed and the plate fin with a fitting tolerance. Therefore, according to the present invention, the flux application process and the flux cleaning process for removing the flux can be eliminated, and the number of production steps can be greatly reduced.

Claims

The scope of the claims  [1] At least semi-cured on the inner surface, a plurality of tubes having a semi-cured coating layer formed on at least the inner surface, and inserting both ends of the tube and arranging the tubes at predetermined intervals. A seat plate on which a coating layer is formed, and a plurality of plate fins inserted into the tube and arranged at predetermined intervals in the longitudinal direction of the tube;  A tank attached to the seat plate and having a completely hardened coating layer formed on the inner surface,  The tube, the seat plate, the plate fin and the tank are mechanically joined by fitting tolerances, and a semi-cured coating layer is formed in the gap between the tube and the seat plate and between the tube and the plate fin. Heat exchange ^^, characterized by complete curing and formation of a seal.  [2] A step of applying a coating liquid to at least the inner surface of the tube and the inner surface of the seat plate, and drying and semi-hardening;  Inserting one end side portion of the plurality of tubes into the one seat plate at a predetermined interval; and  Inserting a plurality of plate fins formed with a plurality of tube insertion holes into the tube and arranging the plurality of plate fins at predetermined intervals in the longitudinal direction of the tube;  Inserting and arranging the other seat plate on the other end side of the tube;  A step of subjecting the tube, the seat plate, and the plate fin core to a final firing step, and a step of caulking a tank formed by applying a coating liquid on the inner surface and drying and completely curing the seat plate after the final firing. The  A method for producing heat exchange ^^ characterized by this.