Heat exchanger

Abstract

A heat exchanger has a clad thin sheet material, a clad thick sheet material that is disposed so as to define a passage between the clad thick sheet material and the clad thin sheet material, and that has a sheet thickness greater than that of the clad thin sheet material, and an inner fin held between the clad materials. The clad thick sheet material and the clad thin sheet material have Zn-containing brazing filler metal layers on their passage sides, respectively, and the post-brazing surface Zn amounts are set so as to satisfy specific conditions. Further, certain conditions concerning the compositions of each of the layers that constitute the clad materials, and the inner fin are set.

1 . A heat exchanger, characterized by comprising:
 a clad thin sheet material;   a clad thick sheet material that is disposed so as to define a passage between the clad thick sheet material and the clad thin sheet material, and that has a sheet thickness greater than that of the clad thin sheet material; and   an inner fin held between the clad thick sheet material and the clad thin sheet material, wherein:   joint regions of the clad thick sheet material, the clad thin sheet material, and the inner fin are joined by brazing;   the heat exchanger is configured such that a cooling target to be attached on an opposite side of the clad thin sheet material from the passage is cooled by heat exchange with a cooling water that flows in the passage;   the clad thick sheet material has a first core material and a first passage-side brazing filler metal layer that covers a surface of the first core material on a passage side thereof;   the clad thin sheet material has a second core material and a second passage-side brazing filler metal layer that covers a surface of the second core material on a passage side thereof;   each of the first and second core materials is formed of an aluminum alloy that contains Mn, Cu, and Si in contents given below and contains at least one selected from Fe, Ti, and Zr in contents given below, with the balance being made of Al and unavoidable impurities   Mn: 0.4 to 1.5 mass %   Cu: 0.05 to 0.8 mass %   Si: 0.05 to 1.0 mass %   Fe: 0.05 to 0.5 mass %   Ti: 0.05 to 0.20 mass %   Zr: 0.05 to 0.15 mass %;   each of the first and second passage-side brazing filler metal layers is formed of an aluminum alloy brazing filler metal that contains Si and Zn in contents given below, with the balance being made of Al and unavoidable impurities   Si: 4.5 to 11.0 mass %   Zn: 0.5 to 6.0 mass %;   the inner fin is formed of an aluminum alloy that contains Mn and Zn in contents given below and contains at least one selected from Cu, Si, Fe, Ti, and Zr in contents given below, with the balance being made of Al and unavoidable impurities   Mn: 0.8 to 1.5 mass %   Zn: 0.5 to 3.0 mass %   Cu: 0.05 to 0.3 mass %   Si: 0.05 to 1.0 mass %   Fe: 0.05 to 0.5 mass %   Ti: 0.05 to 0.20 mass %   Zr: 0.05 to 0.20 mass %; and   assuming that A 1  is an amount of Zn at the surface of the clad thick sheet material on the passage side thereof after brazing and A 2  is an amount of Zn at the surface of the clad thin sheet material on the passage side thereof after brazing, following conditions are satisfied:   A 1 : 0.5 to 3.0 mass %   A 2 : 0.4 to 2.0 mass %   A 1 >A 2 −0.5.   
     
     
         2 . A heat exchanger, characterized by comprising:
 a clad thin sheet material;   a clad thick sheet material that is disposed so as to define a passage between the clad thick sheet material and the clad thin sheet material, and that has a sheet thickness greater than that of the clad thin sheet material; and   an inner fin held between the clad thick sheet material and the clad thin sheet material, wherein:   joint regions of the clad thick sheet material, the clad thin sheet material, and the inner fin are joined by brazing;   the heat exchanger is configured such that a cooling target to be attached on an opposite side of the clad thin sheet material from the passage is cooled by heat exchange with a cooling water that flows in the passage;   the clad thick sheet material has a first core material and a passage-side brazing filler metal layer that covers a surface of the first core material on a passage side thereof;   the first core material is formed of an aluminum alloy that contains Mn, Cu, and Si in contents given below and contains at least one selected from Fe, Ti, and Zr in contents given below, with the balance being made of Al and unavoidable impurities   Mn: 0.4 to 1.5 mass %   Cu: 0.05 to 0.8 mass %   Si: 0.05 to 1.0 mass %   Fe: 0.05 to 0.5 mass %   Ti: 0.05 to 0.20 mass %   Zr: 0.05 to 0.15 mass %;   the passage-side brazing filler metal layer is formed of an aluminum alloy brazing filler metal that contains Si and Zn in contents given below, with the balance being made of Al and unavoidable impurities   Si: 4.5 to 11.0 mass %   Zn: 0.5 to 6.0 mass %;   the clad thin sheet material has a second core material and a sacrificial material layer that covers a surface of the second core material on a passage side thereof;   the second core material is formed of an aluminum alloy that contains Mn, Cu, and Si in contents given below and contains at least one selected from Fe, Ti, and Zr in contents given below, with the balance being made of Al and unavoidable impurities   Mn: 0.4 to 1.5 mass %   Cu: 0.05 to 0.8 mass %   Si: 0.05 to 1.0 mass %   Fe: 0.05 to 0.5 mass %   Ti: 0.05 to 0.20 mass %   Zr: 0.05 to 0.15 mass %;   the sacrificial material layer is formed of an aluminum alloy sacrificial material that contains Zn in a content given below and contains at least one selected from Si, Fe, Mn, Ti, and Zr in contents given below, with the balance being made of Al and unavoidable impurities   Zn: 0.5 to 5.0 mass %   Si: 0.1 to 1.0 mass %   Fe: 0.05 to 0.5 mass %   Mn: 0.1 to 1.1 mass %   Ti: 0.05 to 0.20 mass %   Zr: 0.05 to 0.15 mass %;   the inner fin is a clad material having a third core material and a fin brazing filler metal layer that covers both sides of the third core material or only the clad thin sheet material side of the third core material, the inner fin being formed of an aluminum alloy that contains Mn and Zn in contents given below and contains at least one selected from Cu, Si, Fe, Ti, and Zr in contents given below, with the balance being made of Al and unavoidable impurities   Mn: 0.8 to 1.5 mass %   Zn: 0.5 to 3.0 mass %   Cu: 0.05 to 0.3 mass %   Si: 0.05 to 1.0 mass %   Fe: 0.05 to 0.5 mass %   Ti: 0.05 to 0.20 mass %   Zr: 0.05 to 0.20 mass %;   the fin brazing filler metal layer is formed of an aluminum alloy brazing filler metal that contains Si and Zn in contents given below, with the balance being made of Al and unavoidable impurities   Si: 5.0 to 12.0 mass %   Zn: 0.5 to 3.0 mass %; and   assuming that B 1  is a Zn content at the surface of the clad thick sheet material on the passage side thereof after brazing and B 2  is a Zn content at the surface of the clad thin sheet material on the passage side thereof after brazing, following conditions are satisfied   B 1 : 0.5 to 3.0 mass %   B 2 : 0.4 to 2.0 mass %   B 1 >B 2 −0.5.   
     
     
         3 . The heat exchanger according to  claim 1 , wherein
 the clad thin sheet material has an outer brazing filler metal layer that covers an opposite side of the second core material from the passage, and   the outer brazing filler metal layer is formed of an aluminum alloy brazing filler metal that contains 5.0 to 12.6 mass % of Si, with the balance being made of Al and unavoidable impurities.   
     
     
         4 . The heat exchanger according to  claim 3 , wherein
 the clad thin sheet material has an outer sacrificial material layer between the second core material and the outer brazing filler metal layer, and   the outer sacrificial material layer is formed of an aluminum alloy sacrificial material that contains Zn in a content given below and contains at least one selected from Si, Fe, Mn, Ti, and Zr in contents given below, with the balance being made of Al and unavoidable impurities   Zn: 0.5 to 5.0 mass %   Si: 0.1 to 1.0 mass %   Fe: 0.05 to 0.5 mass %   Mn: 0.1 to 1.1 mass %   Ti: 0.05 to 0.20 mass %   Zr: 0.05 to 0.15 mass %.   
     
     
         5 . The heat exchanger according to  claim 2 , wherein
 the clad thin sheet material has an outer brazing filler metal layer that covers an opposite side of the second core material from the passage, and   the outer brazing filler metal layer is formed of an aluminum alloy brazing filler metal that contains 5.0 to 12.6 mass % of Si, with the balance being made of Al and unavoidable impurities.   
     
     
         6 . The heat exchanger according to  claim 5 , wherein
 the clad thin sheet material has an outer sacrificial material layer between the second core material and the outer brazing filler metal layer, and   the outer sacrificial material layer is formed of an aluminum alloy sacrificial material that contains Zn in a content given below and contains at least one selected from Si, Fe, Mn, Ti, and Zr in contents given below, with the balance being made of Al and unavoidable impurities   Zn: 0.5 to 5.0 mass %   Si: 0.1 to 1.0 mass %   Fe: 0.05 to 0.5 mass %   Mn: 0.1 to 1.1 mass %   Ti: 0.05 to 0.20 mass %   Zr: 0.05 to 0.15 mass %.