JPH10156461A - Rugged shape forming method in metal plate material for heat exchanger having rugged shape for controlling flow of heat exchanging medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove friction between a punch and a plate stock and to prevent local thin wall phenomena by applying a large instantaneous current to an electromagnetic forming oil, pressing plate stock for a plate to a die with a magnetic repulsing force and forming a rugged shape for controlling the flow of a heat exchanging medium to the raw plate. SOLUTION: A projecting part 11a is integrally formed and provided in the zone arranging the raw plate 6 of one side surface of a flat plate coil 11 in correspondence to each groove part 9a of the die 7. The plate stock 6 and the coil 11 are separated in the zone between projecting part 11a and at the same time the plate stock 6 and the coil 11 are arranged in the proximate state the zone of the projecting part 11a by providing the flat plate coil 11 with these projecting parts 11a. By this way, a strong electromagnetic force in the zone of projecting part 11a and a weaker electromagnetic force than it in the zone between the projecting part 11a are respectively influenced to the plate stock 6, and the strong electromagnetic force is influenced to a required part with such a local strength.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a metal plate material for a heat exchanger having an uneven shape for controlling the flow of a heat exchange medium.

[0002]

2. Description of the Related Art Evaporators and radiators for car coolers,
As shown in FIG. 10, a laminated heat exchanger made of aluminum called a Dron cup type used as a heat exchanger such as an oil cooler has two core plates (1) (1) made of a brazing sheet. 1) is overlapped to form a tube element (2), and the tube element (2) and the fins (3) are alternately laminated in a plurality of stages and brazed and integrated. In the laminated heat exchanger, the core plate (1) constituting the tube element (2) has both ends in the longitudinal direction as shown in FIGS. Except in the middle,
A rib (4) extending in the longitudinal direction is formed so as to protrude toward the inner surface, and the tip of the rib (4) abuts on the inner surface of the mating core plate (1) to thereby make the inside of the tube element wider. A plurality of heat exchange medium flow passages (5) in the direction ...
And the flow of the heat exchange medium is controlled.

For example, in the above-mentioned laminated heat exchanger, the ribs (4) of the core plate (1) are formed by:
Conventionally, this has been performed by pressing a blank for the core plate (1) using a die and a punch.

[0004]

However, the punch press method using a die and a punch requires both a punch die and a die die as a die, so that the die cost is high. is there.

[0005] In addition, in the punch press method, the rib (4) is formed by overhanging, and the thickness of the material is reduced particularly in the portion corresponding to the shoulder of the punch due to friction and the like acting between the punch and the base plate. Resulting in. Also, in this punch press method, even when the rib (4) is formed in a plurality of steps, for example, in a three-step press, a local thinning phenomenon occurs in the rib (4) due to a defect such as setting of a mold. Sometimes.

[0006] Such a local thinning phenomenon requires that the ribs (4) be formed in a higher and sharper shape in order to reduce the thickness of the core plate (1) and to improve the flow rate of the heat exchange medium in the tube element. In such a case, the pressure resistance of the heat exchanger is reduced, and the element plate may be broken. In particular, as described above, in the case where the base plate is a brazing sheet in which a brazing material is clad on the surface of a core material, this may cause cracks or the like in a brazing material having lower moldability than the core material.

As a molding method for preventing the local thinning phenomenon, there is a bulge molding method using hydraulic pressure. However, the bulge method generally has a low molding speed and has a problem in productivity.

The present invention has been made in view of the above-mentioned conventional problems, and has been made in view of the above-mentioned problems.
Forming of a metal plate material for a heat exchanger, such as a rib (4), for controlling the flow of a heat exchange medium, at a low mold cost, without causing a local thin-wall phenomenon, and An object is to provide a molding method that can be performed with high productivity.

[0009]

An object of the present invention is to provide a method for forming a metal plate material for a heat exchanger having a concave / convex shape for controlling the flow of a heat exchange medium. An electromagnetically formed coil in which a die having a concave / convex portion for forming a concave / convex shape corresponding to the concave / convex shape formed on the raw plate is arranged on one surface side to be sandwiched, and arranged on the other surface side for sandwiching the plate raw plate. The present invention solves the above problem by applying a momentary large current to the plate and pressing the plate for a plate against the die by a magnetic repulsive force to form an uneven shape for controlling the flow of the heat exchange medium on the plate.

That is, since the molding method of the present invention is based on the so-called electromagnetic molding method, a punch is not required and only a die is required, so that the die cost is reduced by half.

In addition, in the electromagnetic forming, the raw plate for a plate is pressed against the concave / convex portion of the die in a non-contact state to form the die. There is no friction between the base plate and the local thinning phenomenon is prevented.

In addition, since an instantaneous large current is applied to the electromagnetic molding coil to form the irregular shape by the magnetic repulsion, the molding speed is high and the productivity is excellent.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings.

The object to be formed in this embodiment is the ribs (4) of the core plate (1) constituting the tube element (2) of the Dron cup type heat exchanger shown in FIGS.

As shown in FIG. 1, the core plate (6) is made of an aluminum brazing sheet (FIG. 12) in which a brazing material (6b) is clad on both sides of a core material (6a).
(See (b)).

The die (7) has a concave and convex portion (9) for forming a groove (9a) corresponding to the convex shape of the rib (4) to be formed. The die (7) is made of an insulator such as a glass cloth solidified with epoxy resin, a cloth or glass cloth solidified with bakelite, or a metal having low conductivity such as stainless steel. The surface of the die (7) may be coated with an insulator to reduce the coefficient of friction, if necessary.

When forming the ribs (4)... On the raw plate (6) as described above, the electromagnetically formed coil is shown in FIG.
As shown in (b), a die (7) is placed on the base plate (6).
Any surface may be used as long as it can apply an electromagnetic force F from the side opposite to the side on which it is arranged. For example, a flat plate coil (11) as shown in FIG. 1 or a flat plate as shown in FIG. A one-turn coil (12) or a planar spiral coil (13) as shown in FIG. 6 is preferably used.
These coils (11), (12) and (13) are connected to an electric circuit (16) with a capacitor (14) and a switch (15) interposed.

First, the case where the flat coil (11) is used will be described. As shown in FIGS. 1 and 2, the flat coil (11) is made of a flat material having a thickness T of 1 to 100 mm made of a copper alloy such as oxygen-free copper or tough pitch copper, and has a base plate ( 6) and an insulating film for avoiding contact with the dice (7). In this insulating film,
Polyamide, Teflon tape or the like is used. Regarding the size of the coil (11), the length L is set to be slightly longer than the length of the base plate (6), and the width B is set in consideration of a large decrease in the magnetic field in the width direction. 6) of width b1
It is set to 5 times or more.

On one surface of the flat coil (11), projections (11a)... Corresponding to the individual grooves (9a) of the dice (7) are integrally formed in the arrangement area of the base plate (6). It is provided by molding. The flat coil (11) has these convex portions (11a
) Allows the base plate (6) and the coil (11) to be separated from each other in the region between the protrusions (11a) and the base plate (6) in the region between the protrusions (11a).
And the coil (11) can be arranged in proximity to each other, so that the base plate (6) is provided with a strong electromagnetic force in the area of the protrusions (11a). A weak electromagnetic force can also be exerted, and a strong electromagnetic force can be exerted on necessary parts by locally increasing or decreasing the strength. In the flat coil (11), these projections (11a)
Are optional, and a flat plate coil having no convex portion (11a) may be used.

The ribs (4) are formed on the base plate (6) by using the flat coil (11) as follows. That is, a die (7) is provided on one surface side sandwiching the raw plate (6).
And a flat coil (11) is arranged on the other surface side of the raw plate (6), and the raw plate (6) is set so as to be sandwiched between the die (7) and the flat coil (11). . Thereafter, the switch (15) is turned on to apply a large instantaneous current to the coil (11). As a result, the flat coil (11) and the base plate (6) cause a magnetic repulsion, whereby the base plate (6)
Are pressed against the die (7), and ribs (4) are formed on the base plate (6).

In forming, the base plate (6) and the die (7)
May be set on any surface of the flat coil (11). In addition, by setting each of the flat coils (11) on both sides, it is possible to simultaneously form ribs on two base plates by applying a single current using one flat coil (11). Further, the length of the flat coil (11) is increased to arrange a plurality of base plates in series, or the width of the flat coil (11) is increased to set a plurality of base plates in parallel. Alternatively, by increasing both the length and width of the flat coil (11) and arranging a plurality of base plates in both the length direction and the width direction, one flat coil (11) can be used. It is also possible to simultaneously form ribs on a plurality of base plates by applying a current several times.

Next, the case where a flat one-turn coil (12) is used will be described. As shown in FIGS. 3 and 4, the flat one-turn coil (12) has a thickness T made of a copper alloy such as oxygen-free copper or tough pitch copper, similarly to the flat coil (11).
Is a flat plate having a length of 1 to 100 mm, which is bent into a U-shape or a U-shape to form a pair of parallel flat plates (19) (2).
0), and an insulating film is similarly affixed to the surface. Length L and width B of each flat plate part (19) (20)
Is set with the same considerations as in the case of the flat coil (11). The distance H between the flat plate portions (19) and (20) is
It is set in the range of 0.5 to 500 mm. If the distance H is small, sparks may occur. Therefore, it is preferable to insert and fix an insulating plate such as bakelite between the flat plates (19) and (20). The flat plate portions (19) and (20) also repel each other due to the application of the current, so they are preferably fixed.

The ribs (4) are formed by setting the base plate (6) on the outer surface side of one flat plate portion (19) of the flat plate one-turn coil (12) and setting the die (7) on the outside thereof. I do.
Then, the switch (15) is turned on to apply an instantaneous large current to the coil (12). Thereby, the flat plate one-turn coil (12) and the base plate (6) cause magnetic repulsion, and the base plate (6) is pressed against the die (7), and the rib (4) is pressed against the base plate (6).
... are formed.

In this flat plate one-turn coil (12),
As shown in FIGS. 3 and 4, another flat plate portion (20) different from the flat plate portion (19) on which the two raw plates (6) are set.
In addition, by providing grooves and holes (20a) as shown in the drawing corresponding to the individual grooves (9a) of the die (7), the magnetic flux density of the other flat plate (19) corresponding to the holes is formed. Can be increased. Of course, instead of such grooves or holes (20a) as shown in the drawing, similarly to the case of the above-mentioned flat coil (11), a convex portion is formed on the flat plate portion (19) on which the raw plate (6) is set. (11a) may be integrally formed, or may be a structure in which grooves, holes (20a), and convex portions (11a) are omitted.

In forming the base plate (6) and the dice (7), the setting mode may be, as described above, not only the one set on the outer surface side of one flat plate portion (19) but also the configuration shown in FIG.
As shown in (a), they are set on the outer surfaces of both flat portions (19) and (20), respectively, or between the flat portions (19) and (20) as shown in FIGS. Alternatively, one or two sets can be set. This makes it possible to simultaneously form ribs on a plurality of base plates by applying a single current using one flat plate one-turn coil (12). The ribs are simultaneously formed on a plurality of base plates by increasing each flat plate portion (19) (20) in the length direction or the width direction and setting a plurality of base plates (6) on the same surface. And productivity can be improved.

Finally, the case where the planar spiral coil (13) is used will be described. As shown in FIGS. 6 and 7,
The planar spiral coil (13) is formed by winding a copper wire (21) in a spiral shape and molding it with glass cloth, epoxy resin, or the like. Although the planar spiral coil (13) has some difficulty in forming uniformity due to the distribution of the strength of the magnetic field on the upper surface of the coil (13), it has the advantage that a large magnetic field can be generated with little charging energy. With. The ribs (4) are formed by setting the base plate (6) on the upper surface of the planar spiral coil (13) and setting the die (7) on the outside thereof. Then, the switch (15) is turned on to apply an instantaneous large current to the coil (13).

[0027]

EXAMPLE As shown in FIG. 8 (a), as a sample (6), a 0.5 mm thick A3003 core material having a thickness of 0.5 mm was used.
An aluminum brazing sheet clad with a 05 mm brazing material layer was prepared. A die (7) having a groove (9a) having a depth d of 2.1 mm and a width b of 3 mm was prepared. The opening side edge of the groove (9a) was formed as a curved surface having a radius of curvature R1 of 0.75 mm. Then, using a flat plate one-turn coil (12), the capacity of the condenser is 40
0 μF, charging energy 7 kJ, the above sample (6)
Was subjected to electromagnetic molding to form a rib (4). As a comparative example, the same sample (6) and die (7) as described above were used, and as shown in FIG.
In the process, a rib (4) was formed on the sample (6). The punch (51) had a size b2 of 2.4 mm and a peripheral edge portion of a curved surface having a radius of curvature R2 of 0.5 mm. Then, as shown in FIG. 8 (C), the thickness of the ribs (4) at the portions a, b, and c was measured for each of the obtained samples. The wall thickness is 0.36 mm, the wall thickness of the part b is 0.21 mm, the wall thickness of the part c is 0.35 mm, and in the case of electromagnetic molding using a flat plate one-turn coil (12), the wall thickness of the part a is 0.1 mm. The thickness of the portion b was 36 mm, the thickness of the portion b was 0.35 mm, and the thickness of the portion c was 0.33 mm. According to the above test results, according to the electromagnetic forming method of the present invention, a
It has been confirmed that the portions, b and c can be formed to a substantially uniform thickness, and in particular, the local thinning phenomenon of the portion b corresponding to the punch shoulder in the rib (4) can be prevented.

The present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the invention. For example, in the above-described embodiment, the molding target is the rib (6) of the core plate (1) of the stacked heat exchanger, but other metal plates used for heat exchangers other than the stacked type heat exchanger are used. Various irregularities that control the flow of the exchange medium may be used as molding targets. Further, the metal plate is not limited to the brazing sheet, and may be various metal plates such as copper in addition to aluminum. Also, the electromagnetically formed coil is not limited to the above three types, and various types of electromagnetically formed coils may be used.

[0029]

As described above, according to the molding method of the present invention, on one surface side of the plate base plate, there is formed a concave / convex portion having a concave / convex shape corresponding to the concave / convex shape formed on the base plate. A die is arranged, a large instantaneous current is applied to the electromagnetic forming coil arranged on the other surface side sandwiching the plate for plate, and the plate for plate is pressed against the die by magnetic repulsion, and heat exchange is performed on the plate. Since it is to form the uneven shape for controlling the flow of the medium, the die for molding need only be a die,
No punch is required, so that the cost of the mold can be reduced. Moreover, since the plate plate is pressed against the die by the magnetic repulsive force, that is, in a non-contact state, there is no friction between the punch and the plate as in the case of a punch press on the plate plate, Therefore, the occurrence of the local thinning phenomenon can be prevented. In addition, since an instantaneous large current is applied to the electromagnetic forming coil to form the uneven shape by the magnetic repulsion, the forming speed is high and the productivity is excellent. Not only that, since the molding speed is very fast, there is also an effect of suppressing the springback of the base plate,
It can be formed with good shape accuracy. Further, since lubricating oil application is not required as in the case of a punch press, a washing step after molding is not required, and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a method according to a first embodiment and showing a material, a die, and a flat coil in a separated state.

FIG. 2 is a sectional view taken along line II of FIG. 1;

FIG. 3 is a perspective view illustrating a method according to a second embodiment, in which a material, a die, and a flat plate one-turn coil are separated.

FIG. 4 is a sectional view taken along line II-II of FIG. 2;

FIGS. 5A to 5C are cross-sectional views each showing a modified example of the method of the second embodiment.

FIG. 6 is a perspective view showing a method according to a third embodiment, in which a material, a die, and a planar spiral coil are separated.

FIG. 7 is a sectional view taken along line III-III of FIG. 3;

8A is a sectional view of an embodiment of electromagnetic forming using a flat plate one-turn coil, FIG. 8B is a sectional view of a comparative example in the case of a punch press, and FIG. 8C is a sectional view of an obtained rib. .

9A and 9B show the principle of electromagnetic molding. FIG. 9A is a sectional view before molding, and FIG. 9B is a sectional view after molding.

FIG. 10 is an exploded perspective view of the stacked heat exchanger.

FIG. 11 is a plan view of a core plate.

12A is a sectional view taken along the line IV-IV of FIG. 11, and FIG. 12B is an enlarged sectional view of a rib.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Core plate (plate material) 4 ... Rib 6 ... Base plate 7 ... Die 9 ... Forming uneven part 9a ... Groove part 11 ... Plate coil (electromagnetic molding coil) 12 ... Plate 1 turn coil (electromagnetic molding coil) 13 ... Plane Spiral coil (electromagnetic molded coil)

Claims (1)

[Claims] 1. A method of forming a metal plate material for a heat exchanger having a concave-convex shape for controlling a flow of a heat exchange medium, wherein the concave-convex shape is formed on one surface side of a plate plate. A dice having a concave / convex portion for forming a concave / convex shape corresponding to the concave / convex shape to be formed on the base plate is arranged, and a large instantaneous current is applied to an electromagnetic forming coil disposed on the other surface side sandwiching the plate base plate to apply a magnetic force. A forming method, wherein a plate for a plate is pressed against the die by a repulsive force to form an uneven shape for controlling the flow of a heat exchange medium on the plate.