Denso Corporation

Shuji Komoda

Shinichi Hamada

Yasutoshi Yamanaka

Hisashi Nakashima

Takayoshi Harada

A heat exchanger made of aluminum includes a plurality of first plates and a plurality of second plates stacked alternately in the direction along the thickness thereof. The first plates and the second plates each constitute a three-layer structure. A first sacrificing material layer is clad on the side surface of a first core member making up each of the first plates nearer to a cooling water path and a second sacrificing material layer is clad on the side surface of a second core member making up each of the second plates nearer to the cooling water path. A first brazing material layer is clad on the side surface of the first core member nearer to an oil path, and a second brazing material layer is clad on the side surface of the second core member nearer to the oil path. The outer peripheral portions of the first and second plates are bent substantially into a U shape in such a manner that the first brazing material layer is interposed between the outer peripheral edge portions of the first and second plates and the adjacent second and first plates, respectively.

Heat exchanger of aluminum

An assembly (oil cooler unit), under the state where first and second plates ( ) prevent a heat exchange core ( ) from falling from a casing ( ), is provisionally assembled, and this oil cooler unit is dipped in a flux to apply the flux. A seal surface plate ( ) is then assembled to the second plate ( ) and is brazed by heat-brazing in an inert gas atmosphere. Since a flux residue on the seal surface plate ( ) can be drastically reduced in this manner after brazing is complete, the seal surface plate ( ) can secure predetermined surface texture even after brazing is complete while the number of process steps necessary for applying the flux is reduced.

Heat exchanger and brazing method

A heat exchanger has a core portion composed of several pairs of first and second plates laminated with and brazed to one another. Each of the first and second plates is composed a core member, a brazing filler layer formed on a surface of the core member, and a sacrifice layer formed on the other surface of the core member. For instance, to form a pair of the first and second plates, the first plate is formed with a convex portion with an opening portion, and a burring portion of the second plate is inserted into the opening portion and is plastically deformed such that the sacrifice layer of the second plate closely contacts the brazing filler metal layer of the first plate. Then the first and the second plates are brazed together.

Aluminum-made heat exchanger with brazed joint portion

An oil cooler is fixed to an engine via an installation stay provided around an outer periphery of the oil cooler. Thus, the load applied to a core portion is reduced, and the load is dispersed on entire portion of the oil cooler. Thus, the respective stresses applied to respective portions of the oil cooler are very small, and a deformation of the core portion is prevented. Furthermore, since the respective stresses on any portion of the oil cooler is reduced, it is possible to make the oil cooler with aluminum whose strength is lower than that of iron. Furthermore, since the thickness of the installation stay can be reduced, difference in the thermal expansion quantity caused by difference in coefficients of linear expansion of the bolt and the installation stay is significantly reduced, and the loose bolt of the bolt caused by difference in coefficients of linear expansion is prevented.

Oil cooler mounting structure

An oil cooler has a tube disposed in a cooling water passage and defining an oil passage therein, an oil side inner fin brazed to an inside wall of the tube in the oil passage, and a water side inner fin brazed to an outside wall of the tube in the cooling water passage. The thickness Tw of the water side inner fin is thicker than the thickness To of the oil side inner fin. The water side and oil side inner fins are corrugated fins.

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Kariya, Japan

Shuji Komoda