Heat exchanger

Abstract

A heat exchanger with the ends of tubes (10) connected by being inserted into a tank (2) is disclosed. Insertion holes are formed in a protrusion (210) convex outward of the tank (2) along the tube length (X). The junction length ratio B / A is not less than 1.15, where A is the outer peripheral surface length of the tubes (10) and B the peripheral length of the junction between the tubes (10) and the tank (2). The larger the junction length ratio, the more the stress generated in the tubes (10) is distributed and reduced. Especially in the case where the junction length ratio is not less than 1.15, the stress is reduced by one half as compared with the junction length ratio of 1.0.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates to a heat exchanger allowing a fluid to exchange heat or, in particular, to a heat exchanger effectively applicable to an automotive radiator for radiating the heat of the cooling water of a water-cooled engine into the atmosphere. [0003] 2. Description of the Related Art [0004] The conventional heat exchanger is configured by stacking a multiplicity of tubes and a multiplicity of corrugated fins in alternate layers to form a core portion. The longitudinal end of each tube is connected by being inserted into an insertion hole of a tank. Also, to reinforce the core portion, a side plate is arranged at each end of the core portion in the direction along the tube stack (see, for example, Japanese Utility Model Publication No. 3059971 and Japanese Unexamined Patent Publication No. 11-337290). [0005] In the case where this heat exchanger is used as an automotive radiator, however, engine cooling wa...

AI Technical Summary

Benefits of technology

[0009] This invention has been achieved in view of the points described above, and the object thereof is to provide a heat exchanger in which the tubes can be reduced in thickness without shortening the service life thereof.

[0011] The larger the junction length ratio, the more the stress generated in the tubes is dispersed and the smaller the stress becomes. In the case where the junction length ratio is not less than 1.15, for example, the stress is reduced by about one half that of the junction length ratio of 1.0, as shown in FIG. 5. Thus, the tube thickness can be reduced without adversely affecting the service life of the tubes.

[0016] In the heat exchanger including the tubes of aluminum and the tanks of resin, the thermal expansion difference between the tubes and the side plates and between the tubes are absorbed by the resin tanks, and therefore the stress generated in the tubes is relaxed.

[0020] In the case where the tanks are substantially rectangular, as in this invention, on the other hand, the tank width can be reduced by increasing the tube length in the tanks and securing a sufficient flow area.

[0022] The job of bringing the connecting portions into close contact with each other is performed easily while the plate members not formed with insertion holes are not mounted, i.e. while the tube ends are not covered. As a result, the connecting portions can be positively brought into close contact with each other.

Problems solved by technology

This causes a temperature difference and hence a thermal expansion difference between the tubes and the side plates.

Also, in the case where the cooling air amount varies from one part to another of the core portion, a multiplicity of the tubes develop temperature differences in accordance with the positions thereof, thereby causing thermal expansion differences between the tubes.

Nevertheless, the thermal expansion difference between the tubes may not be absorbed, and therefore the tubes develop stress due to the thermal expansion difference between them.

Thus, it is difficult to reduce the tube thickness without the risk of shortening the life of the tubes.

Images