The heat exchanger for vehicles disclosed in Japanese Unexamined Utility Model Publication No. H1-61582 is achieved by forming a heat exchanger for engine cooling water, a heat exchanger for air conditioning and other heat exchangers as an integrated unit, with each heat exchanger provided with a core constituted of a plurality of tubes and fins secured in contact with the tubes and a tube plate that covers the ends of tubes belonging to two cores collectively. In addition, a groove is formed at the circumferential edge of the tube plate, and the bottom portion of the tank main body constituted of a synthetic resin is fitted and fastened through calking at the groove.
The radiator illustrated in FIG. 23(a) is a so-called down-flow radiator and assumes a structure similar to that described above. In more specific terms, this radiator 100 is provided with tank main bodies 102 and 103 constituted of a synthetic resin and disposed at the top and the bottom of a core main body 101 constituted of tubes 104 and fms 105 both constituted of aluminum alloy. As shown in FIG. 23(b), the tank main bodies 102 and 103 each have a flange portion 108 which is fitted via an o-ring at a groove 107 formed at the periphery of an end plate 106 to which ends of the tubes 104 are mounted and the tank main bodies 102 and 103 are each further fastened by using calking tabs 109 formed over specific intervals at the circumferential edge of the end plate 106.
It is to be noted that in FIG. 23(a) illustrating the radiator 100, reference number 110 indicates an intake pipe through which engine cooling water is guided into the upper tank main body 102 and reference number 111 indicates an outlet pipe through which the engine cooling water is discharged from the lower tank main body 103. In addition, a cooling water induction port 116, which is closed off by a cap 112 having a pressure valve, for instance, is provided at the upper tank main body 102. Inside the lower tank main body 103, an oil cooler is provided, and reference numbers 114 and 115 indicate intake/outlet pipes of the oil colors.
However, in the structure of the prior art described above, in which the tubes and the fins constituting the core are formed from aluminum alloy and the tank main bodies are formed from a synthetic resin, there is a problem in that they cannot be formed together. There is another problem in that the recyclability of the radiator itself is poor.
As a solution, a method achieved by forming the members constituting the tank portions with aluminum alloy and then the aluminum alloy tank portions are brazed together with the core in a furnace to achieve an integrated unit may be proposed. However, a problem occurs during the repair process implemented after the brazing process to repair any defective brazing occurring between the individual members constituting the tank portions by means such as torch brazing or the like that is, the brazed areas between the individual members are close to the tubes and fins, the tubes and fins become melted during the repair process.
In addition, while the oil cooler for cooling the automatic transmission oil (hereafter referred to as the A/T oil cooler) is mounted at the same time inside the outlet-side (lower) tank main body 103 in the radiator, if U-shaped tank plates are used, the intake/outlet pipes of the A/T oil cooler become a hindrance to the assembly work. Furthermore, while the intake/outlet pipes of the A/T oil cooler may be enclosed and brazed between the tank plates, this method poses problems in that the shapes in the vicinity of the insertion holes for the intake/outlet pipes are bound to become complicated and in that good brazing is not achieved for the intake/outlet pipes, the tank plates and the like.
An object of the present invention is to provide a heat exchanger with a structure that allows integrated brazing, that achieves an improvement in the assemblability in the mounting of the A/T oil cooler and also achieves good overall assemblability and good recyclability.