CN215955269U - Cooling device - Google Patents

Abstract

The present invention relates to a cooling device. The cooling device can improve durability. The cooling device comprises: a housing main body (21) having a recess; and a cover (22) joined to the case body (21) so as to form a flow space (35) through which the cooling liquid flows together with the case body (21), wherein the cover (22) is welded in a state of being placed on the case body (21), and a portion where an inner surface of the case body (21) on the flow space (35) side intersects with an inner surface (222) of the cover (22) on the flow space (35) side is formed with a melting portion and has an R shape.

Description

Cooling device

Technical Field

The present invention relates to a cooling device.

Background

For example, a cooling device described in patent document 1 includes a cooler in which a cooling medium flowing space is formed by a rectangular heat radiation substrate and a jacket. The heat-radiating base plate is integrally provided with a large number of fins standing upright at the center, and the periphery of the fin group is a flange. The sheath is box-shaped having a recess for receiving the fin group. The jacket is covered with a heat-radiating substrate, the fin group is accommodated in the recess, and the opening of the recess is closed with the heat-radiating substrate. The cooler is manufactured by assembling a heat-radiating substrate and a jacket with solder interposed therebetween at a joint portion thereof and by brazing and heating the assembly.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2019-220539

SUMMERY OF THE UTILITY MODEL

Problem to be solved by utility model

In the cooling device described in patent document 1, the joint between the heat-radiating substrate and the jacket may be a corner portion, and stress may be concentrated at the corner portion. Therefore, when this cooling device is installed in a place where vibration occurs, for example, stress is repeatedly concentrated, and there is room for further improvement in terms of low durability.

The utility model aims to provide a cooling device capable of improving durability.

Means for solving the problems

The present invention accomplished in view of the above object is a cooling device including: a1 st member having a recess; and a 2 nd member joined to the 1 st member so as to form a space through which a cooling medium flows together with the 1 st member, wherein the 2 nd member is welded in a state of being placed on the 1 st member, and a portion where a surface on the space side in the 1 st member and a surface on the space side in the 2 nd member intersect each other is formed into an R shape by forming a melting portion.

Here, the welding may be laser welding or electron beam welding.

Further, the 2 nd member may be irradiated with a laser beam or an electron beam from a side opposite to the 1 st member.

Further, the 2 nd member may be molded from a material having better weldability than the 1 st member.

Further, the 1 st member and the 2 nd member may be formed of an aluminum alloy or a brazing sheet of an aluminum alloy.

The 2 nd member may be flat and placed so that a plate surface thereof is orthogonal to the side wall of the 1 st member, and the surface of the 2 nd member opposite to the 1 st member may be irradiated with a laser beam or an electron beam.

From another viewpoint, the present invention is a method for manufacturing a cooling device, wherein a 2 nd member is placed on a1 st member having a recess, wherein the 2 nd member forms a space through which a cooling medium flows together with the 1 st member, and a laser or an electron beam is irradiated from a side of the 2 nd member opposite to the 1 st member.

Here, the 2 nd member may be flat, the 2 nd member may be placed on the 1 st member so that a plate surface thereof is orthogonal to the side wall of the 1 st member, and the laser beam or the electron beam may be irradiated to a surface of the 2 nd member opposite to the 1 st member.

Effect of the utility model

According to the present invention, a cooling device and the like capable of improving durability can be provided.

Drawings

Fig. 1 is an example of an exploded view of components constituting a cooling device according to an embodiment.

Fig. 2 is a view showing an example of a cross section of the cooling device.

Fig. 3 is a diagram showing an example of a case where the case main body and the cover are joined.

Fig. 4 is a diagram illustrating an example of a process of molding the welded portion.

Fig. 5 is a diagram illustrating another example of the welded portion.

Fig. 6 is a diagram illustrating another example of the welded portion.

Fig. 7 is a diagram illustrating an example of a welded portion in a case where an actual irradiation site is shifted from a target irradiation site to the cover side.

Fig. 8 is a diagram illustrating an example of a process of forming the welding portion in a case where the actual irradiation site is shifted from the target irradiation site toward the case main body side.

Description of the reference numerals

1 … cooling device, 5 … semiconductor module, 10 … heat sink, 20 … case, 21 … case body, 22 … cover, 31 … bottom, 35 … circulation space, 40 … welding part, 41 … fusion part, 42 … heat affected part, 151 … laser head, 411 … projection part, L … laser

Detailed Description

Hereinafter, the embodiments will be described in detail with reference to the drawings.

Fig. 1 is an example of an exploded view of components constituting a cooling device 1 according to an embodiment.

Fig. 2 is a diagram showing an example of a cross section of the cooling apparatus 1.

The cooling device 1 of the embodiment includes: a heat sink 10 having fins 12; and a case 20 that houses the heat sink 10 and forms a space through which the cooling liquid flows. The cooling device 1 is a liquid-cooled cooling device that cools the semiconductor module 5, which is an example of a heat generating body, using a cooling liquid and a heat sink 10.

(case 20)

The case 20 includes a case body 21 having a bottomed concave shape and a cover 22 covering an opening of the case body 21. Further, the case 20 includes: an inflow pipe 25 for allowing the coolant to flow into the housing 20; and an outflow pipe 26 that flows the coolant out of the housing 20.

The housing main body 21 has: a flat plate-like rectangular bottom portion 31; and 4 side walls 32 protruding from the peripheral end of the bottom portion 31 in a direction orthogonal to the plate surface of the bottom portion 31. Also, the case main body 21 has a recess 33 formed by the bottom 31 and the 4 side walls 32.

The 1 st through-hole 323 penetrating the 1 st sidewall 321 is formed in the 1 st sidewall 321 among the 4 sidewalls 32. In addition, a 2 nd through hole 324 penetrating the 2 nd side wall 322 is formed in the 2 nd side wall 322 facing the 1 st side wall 321 among the 4 side walls 32. The inlet pipe 25 is fitted into the 1 st through hole 323, and the outlet pipe 26 is fitted into the 2 nd through hole 324.

The cover 22 is a flat plate-like member. The heat sink 10 is joined to the inner surface 222 of the cover 22, which is the surface on the housing main body 21 side. The bonding method is described in detail later.

On the other hand, the semiconductor module 5 is joined to an outer surface 223, which is a surface of the cover 22 opposite to the inner surface 222.

Here, the semiconductor module 5 includes: an insulating substrate 51; a wiring layer 52 provided on the insulating substrate 51; and a semiconductor element 53 mounted on the wiring layer 52 via a solder layer 54. The semiconductor module 5 further includes a heat transfer layer 55 for transferring heat from the insulating substrate 51 to the cooling device 1.

The heat transfer layer 55 of the semiconductor module 5 is bonded to the outer surface 223 of the cover 22. Examples of a method for joining the heat transfer layer 55 and the cover 22 include soldering, sintering (firing), bonding using a resin, and adhesion using a heat conductive grease.

(heating radiator 10)

The heat sink 10 includes: a flat plate-like portion 11; and a plurality of fins 12 projecting from the flat plate-like portion 11 in a direction orthogonal to the plate surface.

The fins 12 may be exemplified by a columnar shape that is in a columnar direction from the protruding direction of the flat plate-shaped portion 11. In addition, the fin 12 may have a shape cut along a plane orthogonal to the protruding direction (hereinafter, sometimes referred to as a "sectional shape") such as a circle or an ellipse. The cross-sectional shape may be a square, a rectangle, a rhombus, or the like. The fins 12 may be flat plates. In the case of a flat plate shape, the flat plate shape may be parallel to the direction from the inflow tube 25 to the outflow tube 26, or may be a wave shape having a portion inclined with respect to the direction from the inflow tube 25 to the outflow tube 26.

The heat sink 10 can be formed by forging, for example. The material of the heat sink 10 may be, for example, a 1000-type heat sink made of pure aluminum such as copper or a 1100.

The heat sink 10 engages the inner surface 222 of the cover 22. The joining of the heat sink 10 and the cover 22 can be performed by, for example, press fitting, bonding, brazing, laser welding, or electron beam welding.

The cooling device 1 configured as described above is assembled with the semiconductor module 5 as described below.

First, the cover 22 is bonded to the semiconductor module 5. In addition, the cover 22 is joined to the heat sink 10.

Then, the case body 21 is covered with the cover 22 obtained by bonding the heat sink 10 and the semiconductor module 5 so that the semiconductor module 5 is positioned outside and the heat sink 10 is housed inside the case 20, and the opening of the case body 21 is covered with the cover 22.

Thereafter, the case body 21 is joined to the cover 22 using laser welding or electron beam welding.

Thereby, a circulation space 35 through which the coolant flows is formed in the space surrounded by the radiator 10, the cover 22, and the case main body 21.

Next, a method of joining the case main body 21 and the cover 22 will be described.

Fig. 3 is a diagram showing an example of a case where the case main body 21 and the cover 22 are joined.

Fig. 4 is a diagram illustrating an example of a process of molding the welded portion 40.

As shown in fig. 3, the cover 22 is placed on the 4 side walls 32 of the case main body 21. Then, the laser L is irradiated from the laser head 151 of the laser device 150 to the outer surface 223 of the cover 22. Then, the laser torch 151 is moved along the shape of the upper end surface 320 of the 4 side walls 32 of the case main body 21, thereby continuously irradiating the laser beam L to form the soldering portion 40 around the semiconductor module 5.

When the cover 22 is irradiated with the laser light L, the energy of the laser light L is converted into heat, and the cover 22 and the base material itself of the case main body 21 are melted and then rapidly cooled. The welded portion 40 is subjected to structural change by the rapid heating and rapid cooling, and the welded portion 40 is composed of a molten portion 41 that is melted and solidified and a heat-affected portion 42 that is subjected to structural change by welding heat. The heat-affected zone 42 is constituted by a heat-affected zone 42c of the cover 22 and a heat-affected zone 42h of the case main body 21.

In the present embodiment, laser welding is performed so that the shape of the flow space 35 in the melting portion 41 is an R shape. For example, as shown in fig. 4 (d), the melting portion 41 has a convex portion 411 protruding toward the flow space 35 side, and laser welding is performed so that the shape of the convex portion 411 on the flow space 35 side, that is, the tip end shape is curved.

Here, the size of the melting portion 41 is determined by the energy density per unit time. The energy density per unit time becomes large, and a larger melting portion 41 is formed. How the shape of the melting portion 41 changes is determined by the position at which the cover 22 is irradiated with the laser light L. In consideration of the above, the energy density per unit time and the irradiation position of the laser light L are set so that the shape in the flow space 35 in the melting section 41 becomes the R shape.

Fig. 5 and 6 show other examples of the welded portion 40.

When the energy density per unit time is low, only the cover 22 melts and the case main body 21 does not melt as shown in fig. 5 (a). Alternatively, when the energy density is low, as shown in fig. 5 (b), the cover 22 and a part of the upper end portion of the side wall 32 of the case body 21 are melted, and the melted portion 41 falls within the size W in the thickness direction of the side wall 32 of the case body 21. As a result, the joining strength between the cover 22 and the case main body 21 is reduced, and the reliability against the leakage of the coolant from the inside of the flow space 35 is lowered.

On the other hand, focusing on the irradiation position of the laser light L, when the laser light L is irradiated to the inner side (the side of the flow space 35) of the case main body 21 with respect to the extension line Le of the inner surface 211 of the side wall 32, only the cover 22 melts and the case main body 21 does not melt, as shown in fig. 6 (a). Alternatively, when the laser light L is irradiated to the inside (the side of the flow space 35) of the case main body 21 with respect to the extension line Le of the inner surface 211, only a part of the cover 22 and the part inside the upper end portion of the side wall 32 of the case main body 21 are melted as shown in fig. 6 (b). As a result, the joining strength between the cover 22 and the case main body 21 is reduced, and the reliability against the leakage of the coolant from the inside of the flow space 35 is lowered.

On the other hand, when the laser light L is irradiated to the outside of the extension line Le of the inner surface 211 of the case main body 21, as shown in fig. 6 (c), even if the side wall 32 of the case main body 21 is also melted, the melted portion 41 may fall within the size W in the thickness direction of the side wall 32 of the case main body 21, and the melted portion 41 may not protrude into the flow space 35. For example, when the laser light L is irradiated to the outside of the central portion C in the thickness direction of the side wall 32 of the case main body 21, the melting portion 41 may not protrude into the flow space 35 even if the energy density is high, as shown in fig. 6 (C).

In view of the above, in the present embodiment, the target position to which the laser light L is irradiated is set to a position on the extension line Le of the inner surface 211 of the housing main body 21 in the outer surface 223 of the cover 22 (hereinafter, this position may be referred to as a "target irradiation position Lt") (see fig. 4 (a)). However, even if the laser light L is irradiated with the target irradiation site Lt as a target, there is a possibility that the actual irradiation site may be shifted from the target irradiation site Lt. Therefore, even when the laser light L is irradiated to a portion that is supposed to be maximally displaced from the target irradiation portion Lt, the energy density is set so that the melting portion 41 has the convex portion 411 protruding toward the flow space 35 side and the tip of the convex portion 411 is curved.

In addition, as for the adjustment of the energy density per unit time, at least either one of the adjustment of the moving speed of the laser head 151 and the adjustment of the laser output may be adopted. For example, for increasing the energy density per unit time, at least one of a method of reducing the moving speed of the laser head 151 and a method of increasing the laser output may be employed.

The cooling device 1 configured as described above includes: a housing main body 21 as an example of the 1 st member, which has a recess 33; and a cover 22 as an example of the 2 nd member joined to the case main body 21 so as to form a flow space 35 as an example of a space through which a cooling liquid as an example of a cooling medium flows together with the case main body 21. The cooling device 1 is laser-welded with the cover 22 placed on the case body 21. Thus, for example, in comparison with a configuration in which the case main body 21 and the cover 22 are joined by brazing, when brazing the case main body 21 and the cover 22, the cover 22 and the heat sink 10 joined by brazing or the like are not annealed, and therefore, a decrease in strength of the cover 22 and the heat sink 10 due to annealing can be suppressed.

Here, for example, in the case of brazing the case main body 21 and the cover 22, since the inner surface 211 of the case main body 21 and the inner surface 222 of the cover 22 are joined in a state of intersecting at 90 degrees, there is a possibility that a corner portion of 90 degrees or less is formed after joining. Further, when the device is installed in a place where vibration occurs, for example, stress may be repeatedly concentrated, and durability may be reduced.

In contrast, in the cooling device 1, the melting portion 41 is formed in an R-shape at a portion where the inner surface 211 on the side of the flow space 35 in the case main body 21 intersects the inner surface 222, which is an example of the surface on the side of the flow space 35, in the cover 22. Therefore, stress concentration at the intersection of the inner surface 211 of the housing main body 21 and the inner surface 222 of the cover 22 can be suppressed. As a result, the durability of the cooling device 1 can be improved.

In the manufacturing method of the cooling device 1, when the case body 21 and the cover 22 are joined, the cover 22 is placed on the case body 21, and the laser light L is irradiated from the side of the cover 22 opposite to the case body 21. In other words, the cover 22 is irradiated with the laser light L in a state where the case body 21 and the cover 22 are superposed on each other.

Here, for example, the following methods are considered: in a state where the cover 22 is placed on the case body 21, the laser L is irradiated to the contact portion between the case body 21 and the cover 22 in parallel with the plate surface of the cover 22, in other words, the laser L is irradiated to the contact portion between the cover 22 and the case body 21 in parallel with the plate surface of the cover 22. Hereinafter, this method may be referred to as "butt welding".

Consider the following case: a case where the target position to be irradiated with the laser light L at the time of butt welding is set on the contact surface between the upper end surface 320 of the side wall 32 of the case main body 21 and the inner surface 222 of the cover 22, in other words, a case where the target irradiation position Lp at the time of butt welding is set on the contact surface between the upper end surface 320 of the case main body 21 and the inner surface 222 of the cover 22 is considered.

Fig. 7 is a diagram illustrating an example of the welded portion 140 in a case where the actual irradiation site is shifted from the target irradiation site Lp toward the cover 22 side.

When the actual irradiation site is shifted from the target irradiation site Lp toward the cover 22, only the cover 22 melts and the case main body 21 does not melt. Alternatively, as shown in fig. 7, only a part of the cover 22 and a part of the outer side of the upper end portion of the side wall 32 of the case main body 21 are melted. As a result, the joining strength between the cover 22 and the case main body 21 is reduced, and the reliability against the leakage of the coolant from the inside of the flow space 35 is lowered.

Fig. 8 is a diagram illustrating an example of a process of forming the welded portion 140 in a case where the actual irradiation site is shifted from the target irradiation site Lp toward the case main body 21 side.

As shown in fig. 8 (a), when the actual irradiation site is shifted from the target irradiation site Lp toward the housing main body 21, as shown in fig. 8 (d), only the side wall 32 of the housing main body 21 may melt, and the housing main body 21 and the cover 22 may not be joined.

On the other hand, in manufacturing the cooling device 1, the case body 21 and the cover 22 can be joined with high accuracy because the laser light L is irradiated from the side of the cover 22 opposite to the case body 21 in a state where the case body 21 and the cover 22 are overlapped. Therefore, the allowable value of the amount of displacement of the actual irradiation site with respect to the target irradiation site Lt can be increased, and thus the manufacturing can be facilitated.

In the cooling device 1, the cover 22 is preferably formed of a material having better weldability than the case main body 21. If the material of the cover 22 is better in weldability than the material of the case main body 21, heat is more easily conducted to the case main body 21 than if the material of the case main body 21 is better in weldability than the material of the cover 22, and the joining strength between the cover 22 and the case main body 21 is more easily increased even if the energy density per unit time is the same.

For example, the material of the cover 22 may be an a3000 series of aluminum alloy such as a3003, and the material of the case body 21 may be an a6000 series of aluminum alloy such as copper or a 6063. The material of the cover 22 is a brazing sheet obtained by clad-rolling (press-fitting) an a3000 series aluminum alloy and an a4000 series aluminum alloy as a brazing material in a hot rolling process, and examples of the material of the case body 21 include an a6000 series aluminum alloy such as copper and a 6063. The material of the cover 22 may be an a3000 series aluminum alloy or an a4000 series aluminum alloy brazing sheet, and the material of the case body 21 may be an a6000 series aluminum alloy or an a4000 series aluminum alloy brazing sheet. By using a brazing sheet as a material of the case body 21 or the cover 22, corrosion resistance of the case 20 can be improved.

In the cooling device 1, the size of the cover 22 in the thickness direction may be set smaller than the size W of the side wall 32 of the casing main body 21 in the thickness direction. By setting as described above, as compared with the case where the size of the cover 22 in the thickness direction is equal to or larger than the size W of the side wall 32 of the case main body 21, heat is easily conducted to the case main body 21, and even if the energy density per unit time is the same, the bonding strength between the cover 22 and the case main body 21 is easily increased.

In the above embodiment, the case body 21 and the cover 22 are joined by laser welding, but the present invention is not particularly limited to laser welding. For example, the case body 21 and the cover 22 may be joined by electron beam welding. In the electron beam welding, the electron beam may be caused to collide with the cover 22 from the side of the cover 22 opposite to the case body 21 in a state where the case body 21 and the cover 22 are overlapped. The energy density per unit time and the position where the electron beam collides may be set so that the shape in the flow space 35 in the melting portion 41 becomes an R shape.

Claims (6)

1. A cooling device having:

a1 st member having a recess; and

a 2 nd member joined to the 1 st member so as to form a space through which a cooling medium flows together with the 1 st member,

the cooling device is characterized in that,

the 2 nd member is welded in a state of being placed on the 1 st member, and a portion where the surface on the space side of the 1 st member and the surface on the space side of the 2 nd member intersect each other forms a melting portion and has an R-shape.

2. The cooling device of claim 1, wherein the weld is a laser weld or an electron beam weld.

3. The cooling device according to claim 2, wherein a laser or an electron beam is irradiated from a side of the 2 nd member opposite to the 1 st member.

4. A cooling device as claimed in claim 3, wherein the 2 nd member is formed of a material better in weldability than the 1 st member.

5. A cooling device according to claim 3 or 4, wherein the 1 st and 2 nd members are formed of an aluminum alloy or a brazing sheet of an aluminum alloy.

6. The cooling device according to any one of claims 2 to 4, wherein the 2 nd member is flat plate-shaped and is placed so that a plate surface thereof is orthogonal to a side wall of the 1 st member,

irradiating a surface of the 2 nd member opposite to the 1 st member with a laser beam or an electron beam.

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