Flat Tube, Platelike Body for Making the Flat Tube and Heat Exchanger

Abstract

A flat tube includes a pair of upper and lower walls opposed to each other, two side walls interconnecting the upper and lower walls at left and right opposite side edges thereof, and a covering wall provided over the outer surface of the left side wall and brazed to the left side wall. The left side wall is made from a side wall forming portion projecting downward from the upper wall integrally therewith and a side wall forming portion projecting upward from the lower wall integrally therewith by brazing these portions as butted against each other. The covering wall is made by folding a covering wall forming portion formed by extending one side edge of the upper wall. The left side wall including the wall forming portion of the upper wall and the wall forming portion of the lower wall can be protected.

1 : A flat tube comprising a pair of flat walls opposed to each other and two side walls interconnecting the flat walls at opposite side edges thereof, at least one of the opposite side edges of one of the flat walls being provided with a covering wall integral therewith and covering an outer surface of at least one of the side walls. 
   
   
       2 : A flat tube according to  claim 1  wherein the covering wall is made by folding a covering wall forming portion formed by extending said at least one side edge of one of the flat walls. 
   
   
       3 : A flat tube according to  claim 1  wherein the covering wall is joined to the outer surface of said at least one side wall. 
   
   
       4 : A flat tube according to  claim 1  wherein said at least one side wall has a smaller thickness than the other side wall and the covering wall is provided over the outer surface of the side wall of smaller thickness. 
   
   
       5 : A flat tube according to  claim 4  wherein the side wall of smaller thickness is made from side wall forming portions projecting from the corresponding side edges of the two flat walls by joining the side wall forming portions as butted against each other. 
   
   
       6 : A flat tube according to  claim 5  wherein the covering wall covers at least a joint between butted ends of the side wall forming portions in the entire outer surface of the side wall of smaller thickness. 
   
   
       7 : A flat tube according to  claim 5  wherein the covering wall covers the entire outer surface of the side wall of smaller thickness. 
   
   
       8 : A flat tube according to  claim 4  wherein the side wall of large thickness is integral with the two flat walls. 
   
   
       9 : A flat tube according to  claim 1  wherein a plurality of reinforcing walls extending longitudinally of the tube are arranged at a spacing between the two flat walls and interconnect the two flat walls. 
   
   
       10 : A flat tube according to  claim 9  wherein the reinforcing walls are made from reinforcing wall forming portions projecting from each of the two flat walls integrally therewith by joining each corresponding pair of reinforcing wall forming portions of the flat walls as butted against each other. 
   
   
       11 . A platelike body for making a flat tube comprising a pair of flat walls opposed to each other and two side walls interconnecting the flat walls at opposite side edges thereof, at least one of the opposite side edges of one of the flat walls being provided with a covering wall integral therewith and covering an outer surface of one of the side walls, the platelike body being in the form of a single metal plate in its entirety and comprising two flat wall forming portions a connecting portion interconnecting the two flat wall forming portions integrally therewith for making one of the side walls, two side wall forming portions projecting from the respective flat wall forming portions and each formed at a side edge of the flat wall forming portion opposite to the connecting portion, and a covering wall forming portion provided by extending one of the flat wall forming portions at the side edge thereof opposite to the connecting portion. 
   
   
       12 : A flat tube making platelike body according to  claim 11  wherein the side wall forming portions have a thickness smaller than the height of the connecting portion. 
   
   
       13 : A flat tube making platelike body according to  claim 11  wherein the covering wall forming portion has a width not greater than the combined height of the two side wall forming portions and larger than the height of the side wall forming portion of the flat wall forming portion provided with the covering wall forming portion. 
   
   
       14 : A flat tube making platelike body according to  claim 11  wherein the covering wall forming portion has a width equal to the combined height of the two side wall forming portions. 
   
   
       15 : A flat tube making platelike body according to  claim 11  wherein the metal plate is made by rolling an aluminum brazing sheet having a brazing material layer over opposite surfaces thereof the platelike body being covered with the brazing material layer in its entirety except at an outer side surface of the side wall forming portion of the flat wall forming portion not provided with the covering wall forming portion and an outer end face of the covering wall forming portion. 
   
   
       16 : A process for fabricating a flat tube characterized by folding a platelike body according to  claim 11  into a hairpin form at opposite sides of the connecting portion to butt the side wall forming portions against each other, folding the covering wall forming portion to cover outer surfaces of the side wall forming portions therewith, and brazing ends of the side wall forming portions to each other and the covering wall forming portion to the outer surfaces of the side wall forming portions at the same time. 
   
   
       17 : A heat exchanger comprising a pair of headers arranged in parallel as spaced apart from each other, a plurality of flat tubes each according to  claim 1 , the flat tubes being arranged in parallel at a spacing between the headers and having opposite ends joined to the respective headers, and fins arranged in respective air passing clearances between respective adjacent pairs of flat tubes and each brazed to the pair of flat tubes adjacent thereto. 
   
   
       18 : A refrigeration cycle comprising a compressor, a condenser and an evaporator, the condenser comprising a heat exchanger according to  claim 17 . 
   
   
       19 : A vehicle having installed therein a refrigeration cycle according to  claim 18  as a motor vehicle air conditioner. 
   
   
       20 : A refrigeration cycle comprising a compressor, a condenser and an evaporator, the evaporator comprising a heat exchanger according to  claim 17 . 
   
   
       21 : A vehicle having installed therein a refrigeration cycle according to  claim 20  as a motor vehicle air conditioner. 
   
   
       22 : A process for fabricating a heat exchanger characterized by making a plurality of folded bodies from flat tube making platelike bodies each according to  claim 11  by folding each of the platelike bodies into a hairpin form at opposite sides of the connecting portion to butt the side wall forming portions against each other and thereafter folding the covering wall forming portion to cover outer surfaces of the two side wall forming portions therewith, preparing a pair of headers each having folded body inserting holes arranged at a spacing and fins, arranging the pair of headers as spaced apart from each other and arranging the folded bodies and the fins alternately, inserting opposite ends of the folded bodies into the respective inserting holes of the headers, fabricating flat tubes by brazing the side wall forming portions of each folded body to each other and the covering wall forming portion thereof to the outer surfaces of the side wall forming portions, and brazing the flat tubes to the headers and each fin to the flat tubes adjacent thereto simultaneously with the fabrication of the flat tubes.