JP2000320992A - Aluminum heat exchanger and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a fin being jointed to a side plate against damage by making a first fillet at the joint of the side plate and the fin larger than a second fillet at the joint of a tube and the fin. SOLUTION: A bracket for fixing a condenser to the body of a vehicle is fixed to each side plate 19, 20 by means of bolts and each side plate 19, 20 is degreased along with a tube 14. Subsequently, a solder material is applied to the tube 14 and the joint face of the side plate 19, 20 and the fin 15. The assembly is carried into a soldering furnace and heated up to the melting point of the solder material thus soldering the each joint of the assembly integrally. Consequently, a first fillet at the joint of the side plate 19, 20 and the fin 15 is made larger than a second fillet at the joint of the tube 14 and the fin 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum heat exchanger assembled by brazing and a method for manufacturing the same, and is suitable for use in a condenser of a vehicle air conditioner.

[0002]

2. Description of the Related Art FIG. 3 shows a structure near a side plate 20 of a conventional condenser (heat exchanger), in which a multi-hole flat tube 14 having a number of refrigerant passage holes 14a is laminated and arranged. Side plates 20 (only one is shown) press-formed into a U-shaped cross section at both ends in the stacking direction
Are placed between the tubes 14 and between the tubes 14
A fin 15 made of an aluminum clad material clad with a brazing material is arranged between the fin 15 and the side plate 20.

[0003] Then, the tube 14, the side plate 2
After assembling the fins 15 and the like into a predetermined structure, the assembled body is heated to the melting point of the brazing material, and the entire assembled body is integrally brazed. In this case, the size of the fillet at the brazing joint is determined by the cladding ratio of the brazing material of the fin 15, and accordingly, the fillet at each portion has the same size.

[0004] On the other hand, a plate 21a forming a part of a bracket is attached to the side plate 20 by bolts 23, and the condenser is attached to the vehicle via the bracket. Therefore, a thick plate is used for the side plate 20 in order to secure the strength. Therefore, the outer radius Rs of the bent portion of the side plate 20 is also increased, and is inevitably compared with the radius Rt of the end of the tube 14. Rs> R
t.

[0005]

However, when Rs> Rt as described above, the length of the joint between the side plate 20 and the fin 15 in the air flow direction c is smaller than that of the tube 1.
The length of the joint between the side plate 20 and the fin 15 also becomes smaller than the length of the joint between the fin 15 and the fin 15.

Therefore, when an external force acts on the heat exchanger,
The stress at the joint between the side plate 20 and the fin 15 is
The fin 15 which is higher than the stress at the joint between the tube 14 and the fin 15 and is joined to the side plate 20
Had the problem that it was easily damaged at first. In view of the above, an object of the present invention is to prevent breakage of a fin joined to a side plate and improve the durability of a heat exchanger.

[0007]

According to the first and second aspects of the present invention, a fin (1) is provided.
5) replace the tube (14) and the side plate (19,
In the aluminum heat exchanger brazed to 20), the first fillet (24) at the joint between the side plates (19, 20) and the fins (15) is connected to the tube (1).
4) and the second fillet (2) at the joint between the fin (15).
The feature is that it is larger than 5).

According to this, the side plates (19, 2)
0) and the fin (15) can be increased in the area of the joint and the strength of that part can be increased, so that the fin (15) joined to the side plate (19, 20) can be prevented from being damaged, The durability of the heat exchanger can be improved. In addition, when the fillet is increased, the amount of brazing material used and the ventilation resistance increase, but only the fillet (24) at the joint between the side plates (19, 20) and the fins (15) is increased. Accordingly, it is possible to minimize the amount of expensive brazing material used and the increase in ventilation resistance.

According to the third and fifth aspects of the present invention, the amount of the brazing material held at the joint between the side plates (19, 20) and the fins (15) is determined by adjusting the amount of the brazing material to the tubes (14) and the fins (15). ), The fins (15) are brazed to the tubes (14) and the side plates (19, 20) and the fins (15) in a state where the amount of the brazing material is larger than the amount of the brazing material held at the joints.

According to this, the side plates (19, 2)
0) Fillet (24) at the joint between the fin (15)
Can be increased, and the same effect as that of the first aspect can be obtained. According to the fourth aspect of the present invention, the fins (15) are formed of a bare material, and the brazing material is held on the tubes (14) and the side plates (19, 20). (19, 20) and the fin (15) are assembled into a predetermined structure, and brazing is performed.

According to this, for example, in order to change the amount of the brazing material according to the joining portion, the fin (15) is made of a double-sided clad material, of which the amount of the brazing material of the fin joined to the side plates (19, 20) is formed. It is possible to increase the (cladding ratio), but in this case, two types of fins are required, whereas the tube (14) and the side plate (1) are required.
According to the method in which the brazing material is held by the fins (9, 20), the fins (15) arranged between the tubes (14) and the fins (1) arranged on the side plate (19, 20) side.
5) can be formed of a bare material and the same material can be used.

In the invention according to claim 5, the tube (1)
4) is an extruded multi-hole tube, and the tube (14)
, Side plates (19, 20) and fins (15) are formed of a bare material, and a brazing material is applied to the tube (14) and the side plates (19, 20).
4), side plates (19, 20) and fins (15)
Are assembled into a predetermined structure, and brazing is performed.

According to this, since the brazing material is applied to the tube (14) and the side plates (19, 20), it can be easily implemented even in the case of the extruded multi-hole tube (14) in which the use of the clad material is difficult. . In addition, tube (1
4) Fins (15) arranged between each other, and fins (15) arranged on the side plate (19, 20) side.
Can be formed of a bare material and the same material can be used.

[0014] The amount of the brazing material in the present specification refers to
The weight per unit area determined from the area of the brazing material applied or clad and the weight of the brazing material applied or clad on the site. In addition, the code | symbol in the parenthesis of each said means shows the correspondence with the concrete means of embodiment mentioned later.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example in which the present invention is applied to a condenser (heat exchanger) of a vehicle air conditioner.
Is for cooling and condensing a high-temperature and high-pressure superheated gas refrigerant discharged from a compressor (not shown) in a refrigeration cycle of a vehicle air conditioner.

The condenser 10 has a first and a second pair of header tanks 11 and 12 arranged at a predetermined interval.
The first and second header tanks 11 and 12 are made of aluminum and have a substantially cylindrical shape extending vertically.
A core 13 for heat exchange is arranged between the first and second header tanks 11 and 12. The condenser 10 of this example is generally called a multi-flow type,
The core portion 13 has a plurality of flat tubes 14 in which the refrigerant flows in the horizontal direction arranged vertically in parallel between the first and second header tanks 11 and 12, and fins 15 are interposed between the plurality of tubes 14. And joined. Here, the tube 14 is an extruded multi-hole flat tube in which a number of refrigerant passage holes 14a are formed by extrusion of aluminum, similarly to the conventional tube shown in FIG. Also, the fin 15
Is a corrugated fin made of aluminum which is bent in a wavy shape.

One end of the tube 14 communicates with the first header tank 11, and the other end communicates with the second header tank 12. A refrigerant inlet piping joint (refrigerant inlet) 16 is arranged and joined above the first header tank 11. A refrigerant outlet-side piping joint (refrigerant outlet) 17 is arranged and joined below the second header tank 12.

As a result, the refrigerant from the inlet-side pipe joint 16 passes through the first header tank 11 and passes through the core portion 13.
After flowing into the tube 14, it flows through the second header tank 12 to the outlet side pipe joint 17. Side plates 19 and 20 formed in a U-shaped cross section are arranged on both the upper and lower sides of the heat exchange core 13.
The side plates 19, 20 are joined to the outermost corrugated fins 15 and the first and second header tanks 11, 12, and serve as a member for attaching the condenser 10 to the vehicle body.

On both sides of each side plate 19, 20,
A bracket 21 for attaching the condenser 10 to the body 30 of the vehicle is disposed. The bracket 21 is formed by welding a metal second plate 21b to a metal first plate 21a formed in a U-shaped cross section. It is configured integrally. In addition, the bracket 21 includes the second plate 21
b, a rubber vibration isolating member 22 is assembled, and bolts 23
To the side plates 19 and 20.

In the condenser 10, the concrete material of the extruded multi-hole tube forming the tube 14 is an aluminum bear material of A1050, the side plates 19 and 20 are aluminum bear materials of A3003, A specific material is an aluminum bare material of A3003. The first and second header tanks 11,
Numeral 12 is made of a clad material in which a brazing material is clad on an aluminum core material. The inlet-side pipe joint 16 and the outlet-side pipe joint 17 are made of an aluminum bare material.

Next, a method of manufacturing the condenser 10 will be described.
First, each component is processed into a predetermined shape.
Next, a non-corrosive flux is applied to the first and second header tanks 11 and 12, and then the flux is dried. On the other hand, after the tubes 14 and the side plates 19 and 20 are degreased, a brazing material is applied to the joint surfaces of the side plates 19 and 20 with the fins 15 and the tubes 14. Here, the amount of the brazing material applied to the side plates 19 and 20 is larger than the amount of the brazing material applied to the tube 14. In addition, the brazing material application amount means the weight per unit area calculated from the brazing material application area and the brazing material application weight.

The brazing materials are Si, KAlF ₄ and K ₃
It is a mixture (powder) with AlF _6, and this brazing filler metal also has properties as a flux. Then, the brazing material and a binder (for example, an acrylic resin powder) are mixed with a solvent (for example, isopropyl alcohol) to form a mixed solution, and the components are immersed in the mixed solution to apply the brazing material.

Next, the first and second header tanks 11, 1
2, tube 14, fin 15, side plate 19,
20 and other components, and a piping joint 1
6 and 17 are assembled and temporarily assembled to the predetermined heat exchanger structure shown in FIG. Then, a fastening force is applied from both sides in the laminating direction with an appropriate jig to maintain an assembled state of the heat exchanger structure.

Next, while maintaining the assembled state, the assembled body is carried into a brazing furnace, and the assembled body is melted in a brazing furnace filled with nitrogen gas or an inert gas. And brazing the joints of each part of the assembly. Thereby, the assembly of the condenser 10 main body is completed. In the condenser 10 manufactured as described above, the fillet at the joint between the side plates 19 and 20 and the fin 15 is larger than the fillet at the joint between the tube 14 and the fin 15. ,
Since the joint area between the fins 20 and the fins 15 increases and the strength of the parts increases, the breakage of the fins 15 joined to the side plates 19 and 20 is prevented, and the durability of the condenser 10 is improved. Can be.

Next, the relationship between the size and strength of the fillet will be described based on an experimental example. (Experimental example) Table 1 shows that the brazing material application amount Vt of the tube 14 is constant (10 g / m ² ),
Amount Vs applied to joint surface side with fin 15 at the time
The following shows the results of an experiment performed using as a parameter.

The brazing material used in this experiment was Si (about 3
3%), KAlF ₄ (about 60%) and K ₃ AlF ₆ (about 7%).
%), And used in a solvent together with a binder. FIG. 2 shows a schematic shape of a test piece used in this experiment. Fins 15 are arranged between one tube 14 and side plates 19 and 20. The main dimension of the fin 15 is fin plate thickness Tf = 0.0
7 mm, fin pitch Pf = 3.2 mm, fin height H
f = 7.8 mm.

The fillet lengths Ls and Lt in FIG. 2 correspond to the portions of the fillets 24 and 25 that are in contact with the fins 15.
Ls represents the length of the first fillet 24 on the side plates 19 and 20 side, and Lt represents the length of the second fillet 25 on the tube 14 side. Represents The main dimensions of the tube 14 and the side plates 19 and 20 used in the test piece will be described with reference to FIG.
7mm, tube width Wt = 16mm, Rt = 0.85m
m, side plate thickness Ts = 1.6 mm, side plate width Ws = 16 mm, and Rs = 2.4 mm.

Further, the materials of the tube 14, the fin 15, and the side plates 19, 20 are the same as in the above embodiment. The length Lt of the second fillet 25 is constant at 0.55 mm in all the test pieces. The evaluation of the breaking force of the fins 15 was performed by applying a tensile load in the vertical direction in FIG. 2, and the evaluation of the ventilation resistance was performed at a wind speed of 4.5 m / s.

[0029]

[Table 1] First, the relationship between the brazing material application amount Vs of the side plates 19 and 20 and the breaking force of the fin 15 will be described with reference to Table 1. As the application amount Vs increases, the length Ls of the first fillet 24 increases, The breaking force per fin is also increasing.

Then, the brazing material application amount Vt of the tube 14
= 10 g / m ^2, while Vs = 10 g / m ² ,
As in the conventional case, the fin 15 is broken at the joint between the side plates 19 and 20 and the fin 15 (portion a in FIG. 2). Vs
In the case of = 12.5 g / m ² , part a of FIG. 2 breaks, and part of the fin 15 also breaks at the joint between the tube 14 and the fin 15 (part b of FIG. 2),
The breaking force is increasing.

Further, in the case of Vs = 17.5g / m ² or more, the breaking point is moved to the junction between the tube 14 and the fin 15 (b section), side plates 19, 20 and the fins 1
No longer break at the joint with No. 5, and the breaking force further increases. This is because the joint area between the side plates 19 and 20 and the fins 15 increased due to the increase in the length Ls of the first fillet 24.

As described above, the brazing material application amount Vs of the side plates 19 and 20 is made larger than the brazing material application amount Vt of the tube 14, and the fillet length Ls of the side plates 19 and 20 is increased. By making the length longer than the length Lt, the joint area between the side plates 19 and 20 and the fin 15 increases, and the strength of the portion increases, so that the fin 15 joined to the side plates 19 and 20 is damaged. By preventing the above, the durability of the condenser 10 can be improved.

On the other hand, it was confirmed that the ventilation resistance slightly increased with an increase in Vs. This is because the air flow area of the core 13 decreases due to an increase in Ls with an increase in Vs. Here, by increasing only the fillet 24 at the joint between the side plates 19 and 20 and the fin 15, it is possible to minimize the amount of expensive brazing material used and the increase in ventilation resistance.

Further, in order to change the amount of the brazing material according to the joining portion as described above, the fin 15 is made of a double-sided clad material, and the amount of the brazing material of the fin to be joined to the side plates 19 and 20 (cladding rate) ) Is possible, but in this case, two types of fins are required. On the other hand, according to the method of the above embodiment, the fins 15 disposed between the tubes 14 and the side plates 19 are provided. , 2
The same fin 15 can be used as the fin 15 disposed on the zero side.

(Other Embodiments) The present invention is applicable not only to the above-described condenser but also to various heat exchangers (for example, radiators) for vehicles, and further to heat exchangers other than those for vehicles. It is. Further, in the above embodiment, a mixture of Si, KAlF ₄ and K ₃ AlF ₆ is used as the brazing material, but a brazing material mainly composed of aluminum (for example, A4045) may be used.

In the above embodiment, the aluminum heat exchanger using the extruded multi-hole tube 14 is shown. However, the present invention can be applied to an aluminum heat exchanger in which one tube is constituted by a pair of press-formed core plates. Of course. In the above-described embodiment, the brazing material is held by applying the brazing material to the tubes 14 and the side plates 19 and 20. However, the brazing material is formed by forming the tubes 14 and the side plates 19 and 20 with a clad material. May be held.

Further, the fin 15 is made of a double-sided clad material,
Among them, the cladding ratio of the fins joined to the side plates 19 and 20 may be increased. Further, the fins 15 may be a double-sided clad material, and the side plates 19 and 20 may be coated or clad with a brazing material. According to them,
The amount of brazing material at the joint between the side plates 19 and 20 and the fins 15 increases, and the fillet length Ls on the side plates 19 and 20 is changed to the fillet length L on the tube 14 side.
It can be longer than t.

[Brief description of the drawings]

FIG. 1 is a front view of a heat exchanger to which the present invention is applied.

FIG. 2 is a front view of a main part of a test piece used in an experiment.

FIG. 3 is a cross-sectional view near a side plate of a conventional heat exchanger. 14 ... tube, 15 ... fin, 19, 20 ... side plate, 24 ... first fillet, 25 ... second fillet.

Claims (5)

[Claims] 1. An aluminum tube (14) in which a large number of tubes are stacked, and aluminum side plates (1) arranged at both ends in the stacking direction of the tubes (14).
9, 20) and the tubes (14) and between the tubes (14) and the side plates (19, 2).
0) and an aluminum fin (15) that is continuously bent in a wavy shape, and the fin (15) is connected to the tube (14) and the side plate (19, 20) An aluminum heat exchanger brazed to the side plate (19, 20) and the fin (1).
An aluminum heat exchanger characterized in that the first fillet (24) at the joint with the tube (14) is larger than the second fillet (25) at the joint with the tube (14) and the fin (15). . 2. In the first fillet (24),
The length (L) of the fin (15) in the direction continuous in a wave
2. The aluminum heat exchanger according to claim 1, wherein s) is longer than a length (Lt) of the second fillet (25) in a direction in which the fins (15) are continuous in a wave shape. 3. An aluminum tube (14) in which a large number of tubes are stacked and arranged, and aluminum side plates (1) arranged at both ends in the stacking direction of the tubes (14).
9, 20) and the tubes (14) and between the tubes (14) and the side plates (19, 2).
0) and an aluminum fin (15) that is continuously bent in a wavy shape, and the fin (15) is connected to the tube (14) and the side plate (19, 20) A method of manufacturing an aluminum heat exchanger brazed to a side plate (19, 20) and said fin (1).
5) with the amount of brazing material held at the joint between the tube (14) and the fin (15) being larger than the amount of brazing material held at the joint between the tube (14) and the fins (15).
4) and a method of manufacturing an aluminum heat exchanger, comprising brazing the side plates (19, 20) and the fins (15). 4. The fin (15) is formed of a bare material, and a brazing material is held on the tube (14) and the side plates (19, 20). The method for manufacturing an aluminum heat exchanger according to claim 3, wherein the brazing is performed by assembling the plates (19, 20) and the fins (15) into a predetermined structure. 5. The tube (14) is an extruded multi-hole tube, and the tube (14), the side plates (19, 20), and the fins (15) are formed of a bare material. 14) and after applying a brazing material to the side plates (19, 20), the tube (14), the side plates (19, 20), and the fins (15) are assembled into a predetermined structure, and the brazing is performed. The method for manufacturing an aluminum heat exchanger according to claim 3, wherein joining is performed.