Title of Invention: MANUFACTURING METHOD OF HEAT EXCHANGER

Technical Field

[0001]

The present invention relates to a manufacturing method of a heat exchanger having a medium flowing therein so as to exchange heat with an object.

Background Art

[0002]

For example, in a vehicle with a motor as a drive source, a battery configured to supply power to the motor, and a heat exchanger configured to cool this battery are mounted. As related art to the heat exchanger, there is a technique disclosed in patent literature 1.

[0003]

Patent literature 1 discloses that plates are molded by roll bonding so as to manufacture a heat exchanger. More specifically, two plates are partly bonded, and inflated by introducing a fluid into a non-bonded part. The inflated part is to be a medium passage where a medium flows.

Citation List Patent Literature

[0004]

Patent Literature 1: JP-A-11-277167

Summary of Invention Technical Problem [0005]

In molding by roll bonding, a relatively soft material with high moldability is used so that the material is deformed by the introduced fluid. However, in the case that the heat exchanger is made of a soft material, there is a problem that the heat exchanger may be easily damaged, for example, when the heat exchanger accidentally contacts another part at the time of vehicle assembling operation. It is desired to obtain a heat exchanger of high hardness while using a highly flexible material suitably adapted for the molding step.

[0006]

An object of the invention is to provide a manufacturing method of a heat exchanger that makes it possible to obtain a heat exchanger of high hardness while using a highly flexible material suitably adapted for a molding step.

Solution to Problem [0007]

In the following description, reference numerals in the accompanying drawings are appended in parentheses to facilitate understanding of the invention, but the invention is not limited to illustrated embodiments. [0008]

According to a first aspect, there is provided a manufacturing method of a heat exchanger including: a preparation step of preparing plural plates (11, 12) made of metal; a bonding step of superposing the prepared plates (11, 12) on each other and thereafter bonding the plates (11, 12) at predetermined positions; a molding step of injecting a fluid between the bonded plates (11, 12) so as to mold a medium passage (R) ; a heating step of heating at least one plate (11) of the plates (11, 12) to a first temperature; and an aging step of maintaining the plates (11, 12) that have undergone the heating step and the molding step, at a second temperature lower than the first temperature.

[0009]

According to a second aspect, preferably, in the manufacturing method of the heat exchanger according to the first aspect, the heating step is performed between the preparation step and the bonding step.

[0010]

According to a third aspect, preferably, in the manufacturing method of the heat exchanger according to the first aspect, the heating step is performed between the bonding step and the aging step.

[0011]

According to a fourth aspect, preferably, in the manufacturing method of the heat exchanger according to the first aspect, the heating step is performed between the molding step and the aging step.

[0012]

According to a fifth aspect, preferably, in the manufacturing method of the heat exchanger according to any one of the first to fourth aspects, the bonding step is performed by bonding at predetermined positions by laser welding.

Advantageous Effects of Invention [0013]

According to the invention, it is possible to provide the manufacturing method of the heat exchanger that makes it possible to obtain the heat exchanger of high hardness while using the highly flexible material suitably adapted for the molding step.

Brief Description of Drawings

[0014]

FIG. 1 is a perspective view of a heat exchanger according to a first example.

FIG. 2A is a diagram illustrating a preparation step in a manufacturing method of the heat exchanger illustrated in FIG. 1.

FIG. 2B is a diagram illustrating a heating step.

FIG. 2C is a diagram illustrating a superposing step, which is a first half of a bonding step.

FIG. 2D is a diagram illustrating a welding step, which is a second half of the bonding step.

FIG. 2E is a diagram illustrating a molding step.

FIG. 2F is a diagram illustrating an aging step.

FIG. 3A is a diagram illustrating the preparation step in a manufacturing method of a heat exchanger according to a second example.

FIG. 3B is a diagram illustrating the superposing step, which is the first half of the bonding step.

FIG. 3C is a diagram illustrating the welding step, which is the second half of the bonding step.

FIG. 3D is a diagram illustrating the heating step. FIG. 3E is a diagram illustrating the molding step.

FIG. 3F is a diagram illustrating the aging step.

FIG. 4A is a diagram illustrating the preparation step in a manufacturing method of a heat exchanger according to a third example.

FIG. 4B is a diagram illustrating the superposing step, which is the first half of the bonding step.

FIG. 4G is a diagram illustrating the welding step, which is the second half of the bonding step.

FIG. 4D is a diagram illustrating the molding step.

FIG. 4E is a diagram illustrating the heating step.

FIG. 4F is a diagram illustrating the aging step.

Description of Embodiments

[0015]

Embodiments of the invention will be described below based on the accompanying drawings.

[0016]

<First Exampl e>

Refer to FIG. 1. FIG. 1 illustrates a state of a heat exchanger 10 placed on a lower surface of a battery Ba. The battery Ba, for example, supplies power to a motor configured to drive a vehicle. The battery Ba, which comes to have high temperature during operation, is disposed in contact with the heat exchanger 10, and cooled by heat exchange with a heat medium (coolant or cooling water) flowing inside the heat exchanger 10.

[0017]

The heat exchanger 10 includes a first plate 11 (plate 11) in which a concave portion Ila where the heat medium flows is formed, and a second plate 12 (plate 12) of a plate shape that is superposed and welded on this first plate 11. A space surrounded by the concave portion Ila and a portion of the second plate 12 that is superposed on the concave portion Ila is a medium passage R where the heat medium flows.

[0018]

The first plate 11 and the second plate 12 are made of, for example, metal such as an aluminum alloy. The first plate 11 and the second plate 12 may be made of an aluminum alloy of an identical composition or may be made of aluminum alloys of compositions different from each other. When metals of different compositions are used for the first plate 11 and the second plate 12, a soft material of a lower hardness is preferably used for the first plate 11 than for the second plate 12. The reason will be described later.

[0019]

Alternatively, the heat exchanger 10 may be composed of two of such first plates 11 where the concave portions Ila are formed. The medium passage R may be formed by superposing the first plates 11 on each other in such a manner that the concave portions Ila are opposed to each other, or the medium passage R may be formed by opposing the concave portion Ila formed in one of the first plates

11 to a flat surface of the other first plate 11. [0020]

A manufacturing method of such a heat exchanger 10 will be described next. [0021]

Refer to FIG. 2A. First, two or more plates 11 and

12 are prepared (preparation step) . The prepared plates may be the first plate 11 and the second plate 12, or both the two plates may be the first plates 11. Hereinafter, a case in which the first plate 11 of a plane shape and the second plate 12 of a plane shape are prepared will be described as an example.

[0022]

Next, as illustrated in FIG. 2B, of the prepared plates 11 and 12, at least the first plate 11 is heated (heating step) . It is noted that at the heating step, the second plate 12 may be heated at the same time. The heating step is performed, for example, by a heating furnace 21 an inside of which is at 500°C (first temperature) . Time of maintaining the first temperature is set to be, for example, approximately three hours.

[0023]

After ending the heating step, as illustrated in FIG. 2C and FIG. 2D, the first plate 11 and the second plate 12 are superposed on each other and bonded at predetermined positions (bonding step) . [0024]

More specifically, the first plate 11 and the second plate 12 are bonded by laser welding. Peripheral edges of a portion to be the medium passage R are welded to each other by laser welding. The portion to be the medium passage R is not welded.

[0025]

Next, as illustrated in FIG. 2E, the plates 11 and 12 bonded to each other are placed in molding dies 31, and a fluid is injected between the plates 11 and 12 so as to mold the medium passage R (molding step) . After undergoing the molding step, the concave portion Ila is formed in the first plate 11. [0026]

The molding step is performed by bulge molding. Here, as the bulge molding, a hot gas bulge molding method or a cold hydroforming method may be selected. [0027]

Next, as illustrated in FIG. 2F, the plates 11 and 12 where the medium passage R is molded are maintained at a temperature (second temperature) lower than at the time of the heating step for predetermined time (aging step) . Specifically, at the aging step, the plates 11 and 12 are maintained at normal temperature as the second temperature for approximately 24 hours. After undergoing the aging step, the plates 11 and 12 are increased in hardness due to age hardening. [0028]

It is noted that in order to adjust a hardness after the aging step in accordance with components (compositions) of the plates 11 and 12, the aging step may be performed by maintaining approximately 150°C as the second temperature for several hours. [0029]

When ending the aging step, the heat exchanger 10 (see FIG. 1) is completed. The manufacturing method of the heat exchanger 10 will be summarized below. [0030]

The manufacturing method of the heat exchanger 10 includes : the preparation step of preparing the plural plates 11 and 12 made of metal; the bonding step of superposing the prepared plates 11 and 12 on each other and thereafter bonding the plates 11 and 12 at the predetermined positions; the molding step of injecting the fluid between the bonded plates 11 and 12 so as to mold the medium passage R; the heating step of heating at least one plate 11 of the plates 11 and 12 to the first temperature; and the aging step of maintaining the plates 11 and 12 that have undergone the heating step and the molding step, at the second temperature lower than the first temperature. [0031]

The manufacturing method of the heat exchanger 10 includes, in addition to the molding step, the heating step of the plate, and as a step that follows the heating step, the aging step of maintaining the plates at the predetermined temperature (second temperature) so as to harden the plates due to age hardening. Thus, while using a highly flexible material suitably adapted for the molding step, the heat exchanger 10 of high hardness can be obtained [0032]

Moreover, the heating step is performed between the preparation step and the bonding step. Because the heating step is performed prior to the bonding step, only the component that requires the heating step (first plate 11) can be selected in advance and subjected to heating treatment, thereby improving productivity. [0033]

Furthermore, at the bonding step, bonding at the predetermined positions is performed by laser welding. That is, the two plates 11 and 12 superposed on each other are bonded by laser welding. Laser welding makes it possible to bond the plates 11 and 12 kept flat at the bonding step so that the productivity is improved as compared with a case of bonding plates partly having a three-dimensional shape. Besides, in a manner different from bonding by the roll bonding method, the plates can be bonded without being rolled in a plane direction and changed in dimensions, so as to facilitate dimensional management of products, thereby improving the productivity. [0034]

For the first plate 11 where the concave portion Ila is formed at the molding step, a softer material is preferably used than for the second plate 12 where the concave portion Ila is not formed. When a softer material is used for the first plate 11 where the concave portion Ila is formed, moldability can be improved. Meanwhile, a hard material is used for the second plate 12 where the concave portion Ila is not formed, so that strength of the heat exchanger 10 can be enhanced. While being more suitably adapted to the molding step, the heat exchanger 10 of high hardness can be obtained. [0035]

<Second Example>

Next, a manufacturing method of a heat exchanger according to a second example will be described based on the drawings. Parts common to the first example are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0036]

Refer to FIG. 3A. First, two or more plates 11 and 12 are prepared (preparation step) . The prepared plates may be the first plate 11 and the second plate 12, or both the two plates may be the first plates 11. Hereinafter, a case in which the first plate 11 of a plane shape and the second plate 12 of a plane shape are prepared will be described as an example.

[0037]

Next, as illustrated in FIG. 3B and FIG. 3C, the first plate 11 and the second plate 12 prepared are superposed on each other and bonded at predetermined positions (bonding step) .

[0038]

In a manner similar to the first example, the bonding step may be performed by welding peripheral edges of a portion to be the medium passage R (see FIG. 3E) to each other by laser welding. [0039]

Next, as illustrated in FIG. 3D, the plates 11 and 12 bonded to each other are heated (heating step) . The heating step is performed, for example, by a heating furnace 21 an inside of which is at 500°C (first temperature) . Time of maintaining the first temperature is set to be, for example, approximately three hours. [0040]

Next, as illustrated in FIG. 3E, the heated plates 11 and 12 are placed in the molding dies 31, and a fluid is injected between the plates 11 and 12 so as to mold the medium passage R (molding step) . After undergoing the molding step, the concave portion Ila is formed in the first plate 11. [0041]

The molding step is performed by bulge molding. Here, as the bulge molding, a hot gas bulge molding method or a cold hydroforming method may be selected. [0042]

Next, as illustrated in FIG. 3F, the plates 11 and 12 where the medium passage R is molded are maintained at a temperature (second temperature) lower than at the time of the heating step for predetermined time (aging step) . [0043]

When ending the aging step, the heat exchanger 10 (see FIG. 1) is completed. The manufacturing method of the heat exchanger 10 will be summarized below.

[0044]

In the manufacturing method of the heat exchanger according to the second example as well, while using a highly flexible material suitably adapted for the molding step, the heat exchanger 10 of high hardness can be obtained Moreover, use of laser welding can facilitate dimensional management of products, thereby improving the productivity. Furthermore, the softer material is used for the first plate 11 than for the second plate 12, so that while being more suitably adapted to the molding step, the heat exchanger

10 of high hardness can be obtained.

[0045]

In addition, the heating step is performed between the bonding step and the aging step. Because the heating step is performed after the bonding step, both of the plates

11 and 12 can obtain effects by the heating step and the aging step performed after the heating step, so that strength of the whole heat exchanger 10 (see FIG. 1) can be improved.

[0046]

<Third Example>

Next, a manufacturing method of a heat exchanger according to a third example will be described based on the drawings .

[0047]

Refer to FIG. 4A. First, two or more plates 11 and 12 are prepared (preparation step) . The prepared plates may be the first plate 11 and the second plate 12, or both the two plates may be the first plates 11. Hereinafter, a case in which the first plate 11 of a plane shape and the second plate 12 of a plane shape are prepared will be described as an example.

[0048]

Next, as illustrated in FIG. 4B and FIG. 4G, the first plate 11 and the second plate 12 prepared are superposed on each other and bonded at predetermined positions (bonding step) .

[0049]

In a manner similar to the first example, the bonding step may be performed by welding peripheral edges of a portion to be the medium passage R (see FIG. 4D) to each other by laser welding.

[0050]

Next, as illustrated in FIG. 4D, the plates 11 and 12 bonded to each other are placed in the molding dies 31, and a fluid is injected between the plates 11 and 12 so as to mold the medium passage R (molding step) . After undergoing the molding step, the concave portion Ila is formed in the first plate 11.

[0051]

The molding step is performed by bulge molding. Here, as the bulge molding, a hot gas bulge molding method or a cold hydroforming method may be selected. [0052]

Next, as illustrated in FIG. 4E, the molded plates 11 and 12 are heated (heating step) . The heating step is performed, for example, by a heating furnace 21 an inside of which is at 500°C (first temperature) . Time of maintaining the first temperature is set to be, for example, approximately three hours. [0053]

Next, as illustrated in FIG. 4F, the heated plates 11 and 12 are maintained at a temperature (second temperature) lower than at the time of the heating step for predetermined time (aging step) . [0054]

When ending the aging step, the heat exchanger 10 (see FIG. 1) is completed. The manufacturing method of the heat exchanger 10 will be summarized below. [0055]

In the manufacturing method of the heat exchanger according to the third example as well, while using a highly flexible material suitably adapted for the molding step, the heat exchanger 10 of high hardness can be obtained. Moreover, use of laser welding can facilitate dimensional management of products, thereby improving the productivity. Furthermore, the softer material is used for the first plate 11 than for the second plate 12, so that while being more suitably adapted to the molding step, the heat exchanger

10 of high hardness can be obtained.

[0056]

In addition, the heating step is performed between the bonding step and the aging step. Because the heating step is performed after the bonding step, both of the plates

11 and 12 can obtain effects by the heating step and the aging step performed after the heating step, so that strength of the whole heat exchanger 10 (see FIG. 1) can be improved.

[0057]

Furthermore, the heating step is performed as a step immediately before the aging step, so that temperature management can be continuously performed to improve the productivity .

[0058]

It is noted that though the heat exchanger according to the invention has been described based on the examples of using the heat exchanger as a vehicular battery cooling device, the heat exchanger can be also applied as a cooling device of an object other than the vehicular battery and as a warming device of an object.

[0059]

The invention is not limited to the examples as long as operations and effects of the invention are achieved.

Industrial Applicability

[0060]

The manufacturing method of the heat exchanger according to the invention is suitable for a manufacturing method of a vehicular battery cooling device.

Reference Signs List [0061]

10: heat exchanger

11: first plate (plate)

12: second plate (plate)

R: medium passage