Heat transfer device for a motor vehicle and method of making same

A method of making a heat-transfer device for a motor vehicle comprising:

• providing at least one collecting box divided by at least one lengthwise partition into a least two parallel collecting chambers,
• providing a rib/tube block composed of a plurality of tubes and corrugated ribs, with the tubes for the two collecting chambers each forming the same number of terminating channels,
• wherein the tubes are made as multichannel tubes divided by at least one lengthwise separating rib positioned at a level of the at least one lengthwise partition into a number of channels that matches the number of collecting chambers, and
• wherein the at least one lengthwise partition, with its edge facing the tube ends, is provided with recesses with the spacing of the multichannel tubes, said recesses fitting over the separating ribs of the multichannel tubes in a shapewise and flush manner and being tightly connected with the outside contours of the tube ends, said partition exhibiting arcuate profiles adjoining the recesses and configured to abut corresponding arcuate profiles of the tube ends which adjoin the respective separating ribs.