Patent ID: 7604044

Claim:
A heat exchanger comprising: a plurality of tubes stacked on each other in a direction of stack of the tubes; and a pair of header tanks, each header tank having a flow section in which fluid flows, the flow section of each header tank extending continuously in the direction of stack of the tubes, each of the plurality of tubes extending in a longitudinal direction between the pair of header tanks; wherein both end sections of the tubes in the longitudinal direction are joined to the pair of header tanks, the flow section of each header tank and an inside of each tube communicate with each other, a tip position of the tube end section is arranged in an outside region of the flow section, a width of the flow section in a width direction generally perpendicular to both the longitudinal direction and the direction of stack of the tubes is smaller than a width in the width direction of the header tank at the tube end section over the entire length of the header tank, and the width of the flow section of the header tank in the width direction is smaller than a width in the width direction of the inside of the tube in direct communication with the flow section of the header tank; the header tank is composed of a tank section in which the flow section is formed and a plate section to which the tube end section is joined, and a communicating section is provided between the flow section and the tube end section so that both can be communicated with each other through the communicating section; a width of the communicating section in the width direction is larger than the largest width of the flow section of the header tank in the width direction; and an intermediate plate section is interposed between the tank section and the plate section, and the communicating section is composed of an opening section, in which the flow section is open on the plate section side and a plate hole arranged at a position corresponding to the tube end section in the intermediate plate section.