JPH0979788A - Thermal stress preventing structure for heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit the absorption of thermal stress by forming the vicinity of end part of a protector, connected to an end plate, so as to be deformable elastically. SOLUTION: This is a thermal stress preventing structure comprising an elastically deformable spring unit 7 formed by bending the end part of a protector 5, constituting a radiator core 1 so as to be arced and the free end of the spring unit 7 retained by the inside wall 6 of a tank engaging recessed groove 6, formed on an end plate 4, to incorporate into the inside wall 6c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat distortion preventive structure for a heat exchanger used for a radiator of an automobile.

[0002]

2. Description of the Related Art In FIGS. 4 and 7, A is a conventional corrugated fin type heat exchanger, and its radiator core 1 has the following structure. That is, in the figure, 2 is a flat tube arranged in parallel, and the flat tube 2,
When the corrugated fins 3 are interposed between the two, the upper and lower open end portions of the flat tube 2 are inserted into the insertion holes 4a formed in the flat end plate 4, and the corrugated fins located at both outer ends are also inserted. Protectors 5 and 5 are respectively provided at 3a and 3a.

Then, the corrugated fin 3 and the flat tube 2, the corrugated fin 3a and the protector 5, the flat tube 2 and the insertion hole 4a of the end plate 4, and the upper and lower ends 5A of the end plate 4 and the protector 5 which are bent at right angles. Each joint (hereinafter referred to as a netsuke) of
The copper radiator is soldered, and the aluminum radiator is integrally brazed or welded.

Further, the flange portions 8a formed at the open ends of the tank 8 are inserted into the concave grooves 6 formed on the outer circumferences of the upper and lower end plates 4, respectively, through O-rings 9, and the concave grooves are formed. The tank 8 is integrally fixed to the end plate 4 by bending the outer wall 6a of 6 and swaging it.

5 and 6 are other conventional examples, in which the upper and lower ends 5A of the protector 5 are inserted into the mounting holes 4b formed in the end plate 4 (protruding type). 6, the upper and lower ends 5A of the protector 5 are aligned with the outer peripheral surface of the concave groove 6 of the end plate 4, and then the concave groove 6 is formed. A part of the outer wall 6a of 6 is fixed by caulking (caulking type).

[0006]

However, in the conventional structure shown in FIGS. 4 to 6, the protector 5 is fixed to the corrugated fins 3, and the upper and lower ends 5A of the protector 5 are fixed to the end plate 4. Therefore, when hot water flows through the flat tube 2 of the radiator core 1,
Further, the degree of thermal expansion differs between the flat tube 2 that is directly affected by the cooling water and the protector 5 that is only indirectly affected by the cooling water when the temperature of the cooling water becomes normal temperature due to the engine stop.

Therefore, the flat tube 2 due to the temperature difference
Due to the difference in thermal expansion between the flat tube 2 and the protector 5, a thermal stress is applied to the root portion of the flat tube 2 and the end plate 4, and by repeated thermal stress (thermal strain), solder cracking or rooting of the root portion is caused in the copper radiator. There was a risk of cracks in the base material around the welded part and cracks in the tube base material near the root of the aluminum radiator, causing water leaks and other problems.

In order to solve such a problem, in the case of an aluminum radiator, after the core is integrally brazed, the central portion B of the protector 5 may be cut to absorb the thermal strain as shown in FIG. However, this may increase the number of man-hours for assembling the radiator core and may reduce the strength of the radiator core.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, in which the vicinity of the end of the protector joined to the end plate is elastically deformable. The purpose of the invention is to provide a material capable of absorbing thermal strain, and its gist is to form an elastically deformable spring portion by bending the end portion of the protector constituting the radiator core into an arc shape. In the structure for preventing heat distortion of a heat exchanger, the free end of the spring portion is engaged with and fixed to the inner wall of a groove for fitting a tank formed in the end plate.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to the embodiments shown in FIGS. 1 to 3. In FIG. 1, reference numeral 1 is a radiator core of a corrugated fin type heat exchanger, which is provided between the flat tubes 2 and 2. Corrugated fins 3 are interposed between the flat tubes 2, and the upper and lower open ends of the flat tubes 2 are inserted into insertion holes 4a formed in a flat end plate 4.

Reference numeral 5 denotes a pair of left and right protectors disposed on the corrugated fins 3a, 3a located at both outer ends. The corrugated fin 3 and the flat tube 2, the corrugated fin 3a and the protector 5, the flat tube 2 and the end plate 4 are shown. Each joint portion (hereinafter, referred to as a root portion) of the insertion hole 4a is fixed by soldering or brazing. Reference numeral 5b in the figure denotes a heat radiating plate which is erected in parallel from both sides of the protector substrate 5a.

Reference numeral 6 denotes a concave groove formed on the outer circumference of the upper and lower end plates 4 for fitting with the flange portion 8a of the tank 8, and like the conventional example shown in FIGS. It is composed of a wall 6a, a bottom surface portion 6b and an inner side wall 6c, and the bottom surface portion 6b is set at a position lower than the end plate 4.

The protector 5 is, as shown in FIG.
Spring portions 7 that are elastically deformable in the vertical direction are connected to the upper and lower ends of the substrate 5a that is joined to the corrugated fins 3a. The spring portion 7 includes a lower plate portion 7a which is bent inward and upward from the upper and lower ends of the substrate 5a.
And the upper plate portion 7 bent from the lower plate portion 7a outwardly at an acute angle.
The upper plate 7b and the end plate 7c are bent at an obtuse angle from the upper plate 7b in the same direction, and can be elastically deformed between the lower plate 7a and the upper plate 7b.

The mounting of the radiator core 1 is the same as the conventional one except the mounting of the protector 5. Therefore, only the mounting of the protector 5 will be described with reference to FIGS. 1 and 2. In this way, the protector 5 is arranged at the corrugated fins 3a, 3a located at both outer ends with the protruding sides of the lower and upper plate portions 7a and 7b of the upper and lower ends thereof being inward.

The end plate portion 7c of the spring portion 7
Is pressed toward the substrate 5a to elastically deform the lower plate portion 7a and the upper plate portion 7b from the state shown by the dashed line in FIG. 1 to the state shown by the solid line. In this state, the protector 5 is attached to the end plate 4
It is pushed into the concave groove 6 formed on the outer periphery of the end plate 7c, and the upper surface of the end plate portion 7c is placed in contact with the back surface of the end plate 4. At this time, the tip portion of the end plate portion 7c has the concave groove 6
The core 1 assembled in this state is integrally brazed in the furnace because it is positioned by hitting the inner wall 6c of the.

Therefore, as described above, when hot water flows through the tube 2 of the radiator core 1 or when the cooling water reaches normal temperature due to engine stop, thermal expansion due to the temperature difference between the tube 2 and the protector 5 occurs. Due to the difference, the thermal stress at the root of the tube 2 and the end plate 4 is
The spring portion 7 of the protector 5 is elastically deformed in the vertical direction to be absorbed, and thermal strain is prevented from occurring.

3 shows another embodiment, in which the spring portion 7 of the protector 5 has a lateral V-shape, whereas the protector 5 shown in this embodiment has the upper and lower ends of the substrate 5a, respectively. A lateral side composed of a lower plate portion 7a bent obliquely upward to the outside, a side wall portion 7d standing upright from the lower plate portion 7a, and a horizontal portion 7e bent from the side wall portion 7d toward the lower plate portion 7a. The U-shaped configuration is the same as that of the above-described embodiment, except that the side wall 7d is positioned by hitting the inner wall 6c of the groove 6.

[0018]

As described above, the heat distortion preventing structure of the heat exchanger according to the present invention forms an elastically deformable spring portion by bending the end portion of the protector constituting the radiator core into an arc shape. Since the free end of the spring portion is fixed to the inner wall of the groove for fitting a tank formed in the end plate by assembling and fixing, the tube and the protector are affected by the cooling liquid flowing in the tube of the radiator core. The difference in thermal expansion due to the temperature difference is absorbed by the elastic deformation of the spring portion of the protector, which prevents the occurrence of solder cracks in the rooted portion or base material cracks around the rooted portion due to repeated thermal strains, and prevents water leakage and the like. Since there is no need to cut the protector when there is no risk of failure, the strength of the radiator core is improved and the number of assembly steps can be reduced. That, there are various effects such as.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part of a heat exchanger to which a thermal strain prevention structure according to the present invention is applied.

FIG. 2 is a perspective view of components used in the heat exchanger.

FIG. 3 is a longitudinal sectional view of a main part of a heat exchanger according to another embodiment.

FIG. 4 is a longitudinal sectional view of a main part of a conventional heat exchanger.

FIG. 5 is a longitudinal sectional view of a main part of a conventional heat exchanger.

FIG. 6 is a longitudinal sectional view of a main part of still another conventional heat exchanger.

FIG. 7 is a front view of a general-purpose heat exchanger.

[Explanation of symbols]

 1 radiator core 2 flat tube 3 corrugated fin 3a corrugated fin 4 end plate 4a insertion hole 5 protector 5a substrate 6 concave groove 6a outer side wall 6b bottom part 6c inner side wall 7 spring part 7a lower plate part 7b upper plate part 7c end plate part 7d Side wall part 7e Horizontal part 8 Tank 8a Flange part 9 O-ring A Radiator core

Claims (1)

[Claims] 1. An inner wall of a groove for fitting a tank in which an end portion of a protector constituting a radiator core is bent into an arc to form an elastically deformable spring portion, and a free end of the spring portion is formed in an end plate. A heat distortion prevention structure for a heat exchanger, characterized by being locked to and fixed to.