JP6961053B1 - Joined structure and manufacturing method of joined structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joined structure capable of suppressing a decrease in productivity and reliability, and a method for manufacturing the joined structure. SOLUTION: The joint structure has a first member 2 having a stepped portion, a second member 1 arranged so as to be overlapped with the stepped portion of the first member 2, and a first member 2 and a second member. A joint portion 4 formed by friction stir welding of overlapping portions of members 1 and an insulating sealing agent 6 formed along a joint line of the joint portion 4 so as to cover the joint portion 4 are provided. It is prepared. [Selection diagram] FIG. 5

Description

The present application relates to a bonded structure and a method for manufacturing the bonded structure.

Conventionally, for example, friction stir welding is one of the techniques for joining metals. Friction stir welding is a method in which a rotary tool called a tool is inserted into a member to be joined, and the tool is rotated to stir the joint portion to perform solid phase welding. Further, since the friction stir welding can join the members to be joined at a melting temperature or lower, there are many advantages such as a small decrease in strength or deformation of the joined portion due to transformation of the metal structure. However, due to friction stir welding, a large amount of metal scraped out when stirring from the upper surface of the member to be joined is generated as burrs.

For example, in the friction stir welding step used in manufacturing a heat sink for a vehicle power conversion device, burrs are generated on the exposed surface of the joint after the friction stir welding of the heat dissipation base plate to the jacket. If the burr generated in the vehicle power converter falls off and adheres to the terminal of the power module containing the power device, the vehicle power converter is short-circuited and the reliability is lowered. In addition, burrs protruding from the member to be joined may get caught in the worker's clothes or body when handling the parts, which may lead to an unexpected situation.
In the conventional processing process by friction stir welding, after performing friction stir welding, cutting is performed to remove burrs. In addition, as a measure against burrs, a device that removes or suppresses burrs, such as devising a tool shape to suppress the occurrence of burrs and increasing the size of the shoulder so as to suppress the metal scraped out when stirring. Also exists (see, for example, Patent Document 1 or Patent Document 2).

Japanese Patent No. 4774256 Japanese Patent No. 3285013

However, if the width of the friction stir welding tool is increased, a wide processing area must be secured in the product having the member to be welded, and the value of the product decreases as the size increases. Further, even when the cutting process and the tool shape are used, burrs can be removed to some extent, but the burrs cannot be completely removed, and finally manual rework is required. Deburring and visual inspection by rework not only reduces productivity because it increases the number of processes and personnel, but it also reduces reliability because further minute burrs may fall off and lead to functional defects of the product. There was a problem to do.

The present application discloses a technique for solving the above-mentioned problems, and an object of the present application is to provide a bonded structure and a method for manufacturing the bonded structure, which can suppress a decrease in productivity and reliability.

The joint structure disclosed in the present application includes a first member having a stepped portion, a second member arranged so as to overlap the stepped portion of the first member, the first member, and the second member. A joint portion formed by friction stir welding of overlapping portions of the members of the above, and an insulating sealing agent formed along the joint line of the joint portion so as to cover the joint portion. It is a thing.
Further, the method for manufacturing the joint structure disclosed in the present application includes a step of preparing a first member having a stepped portion and a step of arranging the second member on the stepped portion of the first member. , The step of forming a joint portion by friction stir welding the overlapping portion of the first member and the second member, and the insulating property along the joint line of the joint portion so as to cover the joint portion. It is provided with a step of applying a sealing agent to have.

According to the joint structure and the method for producing the joint structure disclosed in the present application, it is possible to obtain the joint structure and the method for producing the joint structure capable of suppressing a decrease in productivity and reliability.

It is sectional drawing for demonstrating the manufacturing method of the cooler according to Embodiment 1. FIG. It is sectional drawing which shows the cooler according to Embodiment 1. FIG. It is sectional drawing which shows the cooler according to Embodiment 1. FIG. It is sectional drawing which shows the cooler according to Embodiment 1. FIG. It is sectional drawing which shows the cooler according to Embodiment 1. FIG. It is sectional drawing which shows the cooler according to Embodiment 2. It is sectional drawing which shows the cooler according to Embodiment 2. It is a perspective view of the power conversion apparatus according to Embodiment 3. It is a perspective view of the power conversion apparatus according to Embodiment 4. It is a perspective view of the power conversion apparatus according to Embodiment 5. It is a perspective view of the power conversion apparatus according to Embodiment 6. It is sectional drawing which shows the manufacturing method of the cooler according to Embodiment 7. It is sectional drawing which shows the cooler according to Embodiment 7. It is sectional drawing which shows the manufacturing method of the cooler according to Embodiment 8. FIG. It is sectional drawing which shows the manufacturing method of the cooler according to Embodiment 8. FIG. It is sectional drawing which shows the manufacturing method of the cooler according to Embodiment 8. FIG. It is sectional drawing which shows the manufacturing method of the cooler according to Embodiment 9. FIG. It is sectional drawing which shows the manufacturing method of the cooler according to Embodiment 9. FIG. It is sectional drawing which shows the manufacturing method of the cooler according to Embodiment 9. FIG. FIG. 5 is a schematic cross-sectional view of the power conversion device according to the tenth embodiment.

Embodiment 1.
Hereinafter, the first embodiment will be described with reference to the drawings. In each drawing, the same reference numerals indicate the same or corresponding parts.

FIG. 1 is a schematic cross-sectional view for explaining a method of manufacturing a cooler according to the first embodiment, and shows a heat dissipation base plate and a jacket before friction stir welding. Further, FIG. 2A is a schematic cross-sectional view showing the cooler according to the first embodiment, showing the cooler in a state where burrs are attached to the exposed surface of the joint portion joined by friction stir welding. Further, FIG. 2B is a schematic cross-sectional view showing the cooler according to the first embodiment, showing the cooler in a state where burrs due to cutting are attached to the exposed surface of the joint portion joined by friction stir welding. 3A and 3B are schematic cross-sectional views showing the cooler according to the first embodiment. Further, the schematic cross-sectional view in each drawing is drawn centering on the left side of the paper surface, and the illustration is omitted on the right side of the paper surface. The structure on the right side of the paper is symmetrical with the structure on the left side of the paper.

As shown in FIG. 1, in the method of manufacturing the cooler 3 of the first embodiment, for example, a jacket 2 containing metal and a heat dissipation base plate 1 containing metal, for example, are prepared, and a heat dissipation base is formed on a step portion 2a of the jacket 2. The plates 1 are placed one on top of the other. Then, as shown in FIGS. 2A and 2B, the friction stir welding portion 4 is formed by friction stir welding the overlapping portion of the jacket 2 and the heat dissipation base plate 1, and a cooler 3 such as a heat sink is formed. As shown in FIGS. 2A and 2B, in the cooler 3 according to the first embodiment, the exposed surface 4a of the friction stir welding portion 4 is formed by the friction stir welding, and the burrs 5a due to the friction stir welding adhering to the exposed surface 4a are formed. appear.

As shown in FIG. 3A, the cooler 3 according to the first embodiment is coated with a sealing agent 6 so as to cover the exposed surface 4a of the friction stir welding portion 4 and the burr 5a by the friction stir welding, and the burr by the friction stir welding. Seal and fix 5a so that it does not fall off from the exposed surface 4a of the friction stir welding joint 4. As shown in FIG. 3A, the cooler 3 according to the first embodiment forms the sealant 6 along the friction stir welding joint line 9 so as to cover the friction stir welding joint 4. By covering the exposed surface 4a of the friction stir welding portion 4 and the burrs 5a generated by the friction stir welding with the sealing agent 6, the burrs 5a containing metal fall off due to external factors such as vibration, for example, the power module 7 described later. It is possible to prevent the terminal 8 from adhering to the terminal 8.

Further, when the burr 5a generated by friction stir welding is large, it is usually removed by cutting. At that time, as shown in FIG. 2B, burrs 5b are generated by cutting processing smaller than the burrs 5a by friction stir welding. Also in this case, as shown in FIG. 3B, the sealant 6 is applied along the joint line 9 of the friction stir welding portion 4 so as to cover the exposed surface 4a of the friction stir welding portion 4 and the burr 5b by cutting. ..
In the method for manufacturing a cooler according to the first embodiment, in addition to the above-mentioned steps, a step of removing burrs 5a generated on the exposed surface 4a of the friction stir welding portion 4 by cutting, and a step of removing the burrs after the removing step are performed. The present invention includes a step of applying the sealing agent 6 to the exposed surface 4a of the friction stir welding portion 4 including the above. As a result, it is possible to prevent the burr 5b containing metal from falling off due to an external factor such as vibration and adhering to the terminal 8 of the power module 7 described later, for example.

In the cooler 3 of the first embodiment, the sealant 6 uses, for example, a silicone-based adhesive having an insulating property and airtightness having a viscosity of 400 to 800 CPS. By using an adhesive having a viscosity of 400 to 800 CPS as the sealant 6, it spreads immediately after the sealant 6 is applied and only prevents the burrs 5a and 5b to be contained from being exposed from the sealant 6. However, since it is easy to apply the sealing agent 6, the productivity is improved.

As described above, the cooler 3 according to the first embodiment prevents the burrs 5a and 5b from falling off by applying the sealing agent 6 which is coagulated later so as to cover the region where the burrs 5a and 5b are present. .. By suppressing burrs 5a and 5b, it is not necessary to increase the size of the friction stir welding tool, which leads to miniaturization of the product and increases in value. Further, by using the sealant 6, the reworking itself becomes unnecessary and the productivity is improved. According to the cooler 3 according to the first embodiment, the sealing agent 6 is applied so as to include the burrs 5a and 5b generated in the joint wire 9 to seal and fix the burrs 5a and 5b, thereby suppressing the burrs 5a and 5b from falling off. , The burrs 5a and 5b can prevent a short circuit of, for example, the power conversion device 100 for a vehicle.

Further, by covering the upper surface of the friction stir welding joint 4 with the sealing agent 6, even if a minute leak should occur in the friction stir welding joint 4, water leakage from the cooler 3 can be reduced, which is reliable. The sex can be improved. Further, by using the silicone adhesive as the sealing agent 6, the solidified sealing agent 6 can contain the water pressure below a certain level, and the coolant of the cooler 3 leaks out and damages the circuit. Can be prevented. Furthermore, as a measure against burrs, the size of the friction stir welding tool has been increased, the need for additional processes or visual inspections has been eliminated, and the miniaturization not only increases the value of the product, but also improves productivity and reduces costs. can.

In the first embodiment, the cooler 3 has been described as an example of a joining structure having a friction stir welding portion 4 formed by friction stir welding. However, for example, a power conversion device 100 for a vehicle having a cooler 3 Is also a bonding structure having a friction stir welding portion 4 formed by friction stir welding.
The bonded structure according to the first embodiment is a first member having a stepped portion 2a, for example, a jacket 2, and a second member, for example, a heat radiating base plate 1 arranged so as to overlap the stepped portion 2a of the first member. A joining line 9 of a friction stir welding portion 4 formed by friction stir welding of a member and an overlapping portion of a first member and a second member, and a friction stir welding joint 4 so as to cover the friction stir welding joint 4. A sealing agent 6 having an insulating property, which is formed along the above, is provided.

Further, the method for manufacturing the joint structure according to the first embodiment includes a step of preparing a first member having a stepped portion 2a, for example, a jacket 2, and a stepped portion 2a of the first member, for example, a heat radiation base plate 1. A step of arranging a second member in an overlapping manner, a step of forming a friction stir welding portion 4 by friction stir welding of an overlapping portion of a first member and a second member, and a step of covering the friction stir welding portion 4. As described above, a step of applying an insulating sealing agent 6 along the joint line 9 of the friction stir welding portion 4 is provided.
According to the bonded structure and the method for manufacturing the bonded structure according to the first embodiment, the productivity can be improved and the decrease in reliability can be suppressed.

Embodiment 2.
4 and 5 are schematic cross-sectional views showing the cooler according to the second embodiment. Regarding the description of the cooler 3 according to the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted as appropriate.
As shown in FIG. 4, a power module 7 having a built-in power device is already mounted on the heat dissipation base plate 1 of the cooler 3 according to the second embodiment. In the second embodiment, as shown in FIG. 5, the heat radiation base plate 1 on which the power module 7 is mounted and the jacket 2 are joined by friction stir welding, and then the burr 5b containing the metal generated by the cutting removal process is sealed. It is covered with a stopper 6.
In the second embodiment, since the distance between the exposed surface 4a of the friction stir welding portion 4 and the signal terminal 8 is short, it is possible to solve the conventional problem that deburring and the like cannot be repaired, and the workability and friction can be solved. It is possible to improve the degree of freedom as a processing method for friction stir welding.

Embodiment 3.
FIG. 6 is a perspective view of the power conversion device according to the third embodiment. In the power conversion device 100 which is the joint structure of the third embodiment, a plurality of power modules 7 are mounted on the surface of the heat dissipation base plate 1. Further, the joint line 9 of the friction stir welding portion 4 is formed in a rectangular shape on the surface of the heat radiation base plate 1, and the sealing agent 6 is provided at the corner of the joint line 9 of the friction stir welding joint 4. ing. In the third embodiment, the sealing agent 6 is applied to a portion of the joining wire 9 where burrs 5a and 5b are likely to be generated or adhered. The places where burrs 5a and 5b are likely to be generated or adhered are places where the traveling direction of the friction stir welding tool changes, for example, corners of the joining line 9. In the power conversion device 100 of the third embodiment, the burrs 5a and 5b can be efficiently sealed with the sealant 6, and the productivity can be improved.

Embodiment 4.
FIG. 7 is a perspective view of the power conversion device according to the fourth embodiment. In the power conversion device 100 of the fourth embodiment, a plurality of power modules 7 are mounted on the surface of the heat dissipation base plate 1. Further, on the surface of the heat dissipation base plate 1, the joint line 9 of the friction stir welding portion 4 is formed in a rectangular shape. The power module 7 has a terminal 8, and the sealant 6 is provided on a friction stir welding portion 4 formed at a position facing the terminal 8 of the power module 7. In the power conversion device 100 according to the fourth embodiment, only the portion of the junction wire 9 near the terminal 8 of the power module 7 is covered. In the fourth embodiment, when the heat dissipation base plate 1 on which the power module 7 is mounted and the jacket 2 are friction-stir welded, reworking itself such as deburring of a portion near the terminal 8 of the power module 7, which was difficult in the past, becomes unnecessary. It is possible to improve the degree of freedom in design.

Embodiment 5.
FIG. 8 is a perspective view of the power conversion device according to the fifth embodiment. In the power conversion device 100 of the fifth embodiment, a plurality of power modules 7 are mounted on the surface of the heat dissipation base plate 1. Further, a joint line 9 of the friction stir welding portion 4 is formed in a rectangular shape on the surface of the heat radiation base plate 1, and the heat radiation base plate 1 and the jacket 2 are formed by friction stir welding at the central portion of the cooler 3. A central junction (not shown) is provided. The sealant 6 is provided in the central portion of the cooler 3 so as to cover the central joint portion.

The central joint formed by friction stir welding the heat radiation base plate 1 and the jacket 2 is required when the size of the cooler 3 such as a heat sink is large. The sealant 6 is applied to a central joint portion which is a friction stir welding joint formed in the central portion of the cooler 3. In the fifth embodiment, it is possible to eliminate the burrs 5a and 5b of the central joint portion in the center of the heat dissipation base plate 1, which was difficult to remove when the power module 7 is already mounted, and the productivity can be improved. can.

Embodiment 6.
FIG. 9 is a perspective view of the power conversion device according to the sixth embodiment. In the power conversion device 100 of the sixth embodiment, a plurality of power modules 7 are mounted on the surface of the heat dissipation base plate 1. The sealant 6 is formed on the entire circumference of the joint line 9 of the friction stir welding portion 4. Further, as shown in the eighth embodiment, the sealing agent 6 may be provided in the central portion of the cooler 3 so as to cover the central joint portion. In the ninth embodiment, by covering all of the joint line 9 and the central joint portion where the burrs 5a and 5b containing metal can be generated, it is not necessary to perform the reworking process, and the production efficiency can be improved.

Embodiment 7.
FIG. 10A is a schematic cross-sectional view showing the method of manufacturing the cooler according to the seventh embodiment, and FIG. 10B is a schematic cross-sectional view showing the cooler according to the seventh embodiment. As shown in FIG. 10A, the heat radiation base plate 1 is provided with a groove or a step 10 in advance at a position where the jacket 2 overlaps with the step portion 2a. In the cooler 3 according to the seventh embodiment, a groove or a step 10 is provided in advance on the track that becomes the joint line 9 of the friction stir welding portion 4 formed by the friction stir welding. Since the sealant 6 is provided in a state of being accumulated inside the groove or the step 10, the cooler 3 of the seventh embodiment suppresses the spread of the sealant 6 and a relatively small amount as shown in FIG. 10B. Sealing is possible by using the sealing agent 6 of.

Embodiment 8.
11A to 11C are schematic cross-sectional views showing a method of manufacturing a cooler according to the eighth embodiment. In the method for manufacturing a cooler according to the eighth embodiment, as shown in FIG. 11A, first, the friction stir welding portion 4 is formed by friction stir welding the overlapping portion of the jacket 2 and the heat radiation base plate 1. Then, as shown in FIGS. 11A and 11B, the region including the exposed surface 4a of the friction stir welding portion 4 is pressed by the press device 11 to crush the burrs 5a or 5b. After crushing the burrs 5a or 5b by press working, the sealant 6 is applied to the cooler 3 having the exposed surface 4a containing the crushed burrs 5c as shown in FIG. 11c. In the method for manufacturing the cooler 3 according to the eighth embodiment, the height of the burrs is reduced by the press by the press device 11 to prevent the burrs from squeezing out from the sealant 6, and the processing or inspection step is performed. Sealing is possible by applying a relatively small amount of the sealing agent 6 without any addition.

Embodiment 9.
12A to 12C are schematic cross-sectional views showing a method of manufacturing a cooler according to a ninth embodiment. As shown in FIG. 12A, in the ninth embodiment, for example, a jacket 2 containing metal and a heat radiating base plate 1 containing metal, for example, are prepared, and the heat radiating base plate 1 is arranged so as to overlap the stepped portion 2a of the jacket 2. An outer wall 12a is provided on the outer periphery of the jacket 2. Further, the heat radiation base plate 1 is provided with an inner wall 12b configured to surround the friction stir welding portion 4 together with the outer wall 12a. The outer wall 12a and the inner wall 12b serve as a wall portion of the sealing agent 6. As shown in FIG. 12B, the friction stir welding portion 4 is formed by friction stir welding the overlapping portion of the jacket 2 and the heat dissipation base plate 1, and a cooler 3 such as a heat sink is formed. As shown in FIG. 12B, in the cooler 3 according to the ninth embodiment, the exposed surface 4a of the friction stir welding portion 4 is formed by the friction stir welding, and burrs 5a are generated by the friction stir welding adhering to the exposed surface 4a.

As shown in FIG. 12c, the cooler 3 according to the ninth embodiment forms the sealant 6 along the friction stir welding joint line 9 so as to cover the friction stir welding joint 4. The sealant 6 is filled in the internal space surrounded by the walls of the outer wall 12a and the inner wall 12b. In the cooler 3 of the ninth embodiment, the spread of the sealant 6 can be restricted by providing wall portions on the heat radiating base plate 1 and the jacket 2 respectively. In the ninth embodiment, since the spread-restricted sealant 6 fills the internal space between the walls, a relatively small amount of the sealant 6 is applied without additional processing or inspection steps. Sealing is possible.

Embodiment 10.
FIG. 13 is a schematic cross-sectional view of the power conversion device according to the tenth embodiment. As shown in FIG. 13, the power conversion device 100 according to the tenth embodiment is provided between the support resin 13 provided above the sealant 6 and the support resin 13 and the terminal 8 of the power module 7. It has a support bus bar 14.
In the power conversion device 100 of the tenth embodiment, the support resin 13 to be attached later is assembled from above before the sealing agent 6 solidifies. Even in the conventional assembly process of the power conversion device 100, when the support resin 13 is assembled to the cooler 3, an adhesive is applied between them. In the tenth embodiment, the encapsulant 6 acts as an adhesive between the support resin 13 and the cooler 3, so that the number of steps can be reduced and the productivity can be increased.

Although the present application describes various exemplary embodiments and examples, the various features, embodiments, and functions described in one or more embodiments are applications of a particular embodiment. It is not limited to, but can be applied to embodiments alone or in various combinations.
Therefore, innumerable variations not illustrated are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

1 Heat dissipation base plate, 2 jacket, 2a stepped part, 3 cooler, 4 friction stir welding part, 4a exposed surface, 5a, 5b, 5c burr, 6 sealant, 7 power module, 8 terminal, 9 joint line, 10 Groove or step, 11 press device, 12a outer wall, 12b inner wall, 13 support resin, 14 support busbar, 100 power converter

Claims (14)

The first member having a stepped portion and
A second member arranged so as to overlap the step portion of the first member, and
A joint formed by friction stir welding the overlapping portion of the first member and the second member,
A joint structure comprising an insulating sealing agent formed along a joint line of the joint so as to cover the joint. On the surface of the second member, the joint line of the joint portion is formed in a rectangular shape.
The bonding structure according to claim 1, wherein the sealing agent is provided at a corner portion of the bonding portion. The joint structure according to claim 1 or 2, wherein the sealant is formed on the entire circumference of the joint line of the joint portion. The second member is provided with a groove or a step at the position of the overlapping portion.
The bonded structure according to any one of claims 1 to 3, wherein the sealing agent is provided in a state of being accumulated inside the groove or the step. The first member and the second member are each provided with a wall portion surrounding the joint portion.
The bonded structure according to any one of claims 1 to 4, wherein the sealing agent is filled in an internal space surrounded by the wall portion. The first member is a jacket of a cooler having a refrigerant inside, and the second member is a heat dissipation base plate.
The joint structure according to any one of claims 1 to 5, wherein a power module having terminals is mounted on the heat radiation base plate. The joint structure according to claim 6, wherein the sealant is provided at the joint portion facing the terminal of the power module. A central joint formed by friction stir welding the heat radiation base plate and the jacket is provided in the central portion of the cooler.
The joint structure according to claim 6 or 7, wherein the sealant is provided in the central portion of the cooler so as to cover the central joint portion. A support resin provided above the sealant and
The bonded structure according to any one of claims 6 to 8, further comprising a bus bar provided between the support resin and the terminal of the power module. The process of preparing the first member having a stepped portion and
A step of superimposing the second member on the step portion of the first member and arranging the second member.
A step of forming a joint portion by friction stir welding the overlapping portion of the first member and the second member.
A method for producing a joint structure, comprising: a step of applying an insulating sealing agent along a joint line of the joint so as to cover the joint. A process of removing burrs generated on the exposed surface of the joint by cutting and
The method for manufacturing a bonded structure according to claim 10, wherein after the removing step, the sealing agent is applied to the exposed surface of the bonded portion including the cut portion. The method for producing a joint structure according to claim 10 or 11, wherein the sealant is applied to the entire circumference of the joint line of the joint portion. The method for manufacturing a bonded structure according to claim 10, wherein the burrs formed on the exposed surface of the bonded portion are crushed by press working, and then the sealing agent is applied. The first member is a jacket of a cooler having a refrigerant inside, and the second member is a heat dissipation base plate.
The method for manufacturing a bonded structure according to any one of claims 10 to 13, wherein a power module incorporating a power device is mounted on the heat radiation base plate.

Images