Heat exchanger

Abstract

A heat exchanger has tubes defining refrigerant passages therein and fins disposed between the tubes. The tubes have tube main walls opposed to each other. The fins are joined to the tube main walls. The tube main walls have projections that project inside of the tubes and define recesses on outer sides of the tubes. Each of the tubes has an outer dimension, in a direction perpendicular to the tube main walls, in a range between equal to or greater than 0.8 mm and equal to or less than 1.9 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which like parts are designated by like reference numbers and in which:

FIG. 1 is a perspective view of a heat exchanger according to a first embodiment of the present invention;

FIG. 2 is a schematic perspective view of a part of the heat exchanger according to the first embodiment;

FIG. 3A is a perspective view for showing a step of forming projections and recesses on a plate member for the heat exchanger according to the first embodiment;

FIG. 3B is a perspective view for showing a step of folding the plate member according to the first embodiment;

FIG. 4 is a perspective view for showing a step of joining formed tube members as another example of forming a tube for the heat exchanger according to the first embodiment;

FIG. 5 is a graph showing a relationship between the height of the tube and efficiency of heat transfer of air according to the first embodiment;

FIG. 6 is a graph showing a relationship between pitch of projections of the tubes and efficiency of heat transfer of air according to the first embodiment;

FIG. 7 is a graph showing a relationship between the height of fins of the heat exchanger and efficiency of heat transfer of air according to the first embodiment;

FIG. 8 is a schematic perspective view of a part of a heat exchanger according to a second embodiment of the present invention;

FIG. 9 is a schematic perspective view of a part of a heat exchanger according to a third embodiment of the present invention;

FIG. 10 is a schematic perspective view of a part of a heat exchanger according to a fourth embodiment of the present invention;

FIG. 11 is a schematic perspective view of a part of a heat exchanger according to a fifth embodiment of the present invention;

FIG. 12 is a schematic perspective view of a part of a heat exchanger according to a sixth embodiment of the present invention;

FIG. 13 is a schematic perspective view of a part of a heat exchanger according to a seventh embodiment of the present invention;

FIG. 14 is a schematic perspective view of a part of a heat exchanger according to an eighth embodiment of the present invention;

FIG. 15 is a perspective view for showing a step of forming a tube of the heat exchanger according to the eighth embodiment; and

FIG. 16 is a schematic perspective view of a part of a heat exchanger according to a ninth embodiment of the present invention.

Claims

1. A heat exchanger for performing heat exchange between a refrigerant and an external fluid, comprising: tubes defining passages therein for allowing the refrigerant to flow, the tubes having tube main walls opposed to each other; andfins disposed between the tubes and joined with the tube main walls, whereinthe tube main walls have projections that project inside of the tubes and define recesses outside of the tubes for allowing the external fluid to flow, andeach of the tubes has a tube outer dimension in a range between at least 0.8 mm and at most 1.9 mm, in a direction perpendicular to the tube main walls.

2. The heat exchanger according to claim 1, wherein the tube outer dimension is in a range between at least 1.0 mm and at most 1.6 mm.

3. The heat exchanger according to claim 2, wherein the tube outer dimension is in a range between at least 1.2 mm and at most 1.4 mm.

4. The heat exchanger according to claim 1, wherein the projections are arranged at a predetermined pitch with respect to a longitudinal direction of the tube, andthe predetermined pitch is in a range between at least 1.0 mm and at most 6.5 mm.

5. The heat exchanger according to claim 4, wherein the predetermined pitch is in a range between at least 1.6 mm and at most 5.7 mm.

6. The heat exchanger according to claim 5, wherein the predetermined pitch is in a range between at least 2.3 mm and at most 5.0 mm.

7. The heat exchanger according to claim 1, wherein each of the fins has a fin outer dimension in a range between at least 2.0 mm and at most 9.0 mm, in the direction perpendicular to the tube main walls.

8. The heat exchanger according to claim 7, wherein the fin outer dimension is in a range between at least 3.0 mm and at most 7.3 mm.

9. The heat exchanger according to claim 8, wherein the fin outer dimension is in a range between at least 4.0 mm and at most 6.0 mm.

10. The heat exchanger according to claim 1, wherein the projections extend continuously from upstream ends to downstream ends of the tubes with respect to a flow direction of the external fluid flowing outside of the tubes.

11. The heat exchanger according to claim 1, wherein each of the tubes has a first tube member and a second tube member joined with the first tube member, and the tube main walls of each tube are included in the first and second tube members.

12. The heat exchanger according to claim 11, wherein the first tube member and the second tube member have an identical shape.

13. The heat exchanger according to claim 1 wherein each of the tubes has a separation wall for separating an inner space of the tube into a plurality of spaces in a direction perpendicular to a longitudinal direction of the tube, andthe separation wall is integrated with the tube main walls.

14. The heat exchanger according to claim 1, wherein the projections have curved shapes extending along the tube main walls in a meandering manner in a direction perpendicular to a longitudinal direction of the tubes.

15. The heat exchanger according to claim 1, wherein the projections have straight shapes extending along the tube main walls and obliquely with respect to a longitudinal direction of the tubes.

16. The heat exchanger according to claim 1, wherein the projections have V-shapes that extend along the tube main walls and diverging in a longitudinal direction of the tubes.

17. The heat exchanger according to claim 1, wherein the projections are meshed along the tube main walls.

18. The heat exchanger according to claim 1, wherein the projections have side walls extending perpendicular to outer surfaces of the tube main walls, andthe side walls define edged corners with the outer surfaces of the tube main walls.

19. The heat exchanger according to claim 1, wherein the projections have side walls extending perpendicular to outer surfaces of the tube main walls, andthe side walls define curved corners with the outer surfaces of the tube main walls.

20. The heat exchanger according to claim 1, wherein the fins are corrugated fins including first fin walls and second fin walls connecting the first fin walls, andthe first fin walls are flat and joined with outer surfaces of the tube main walls.

21. The heat exchanger according to claim 20, wherein the second fin walls have louvers that are angled with respect to a flow direction of the external fluid flowing through the fins.

22. The heat exchanger according to claim 1, wherein the external fluid is air for cooling the refrigerant.