Welding methods and structures

Abstract

To reduce laser output needed for laser welding while suppressing a welding defect from occurring.SOLUTION: There is provided a welding method that performs laser welding on a first member and a second member one over the other through irradiation with laser light from a first member side, and that irradiates a thin part with the laser light from the first member side after forming the thin part which is thinner in thickness than other regions in a predetermined region of the first member.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a welding method and a structure.

Background Art

[0002] In recent years, in a cooling device composed of members formed using an aluminum material such as aluminum or an aluminum alloy, in order to join members formed using an aluminum material, it has been proposed to perform soldering or brazing. For example, the liquid-cooled cooling device described in Patent Document 1 is configured by brazing an aluminum inlet header to one end face of the inflow portion of the coolant flow body, brazing an aluminum outlet header to one end face of the outflow portion, and brazing an aluminum intermediate header to the other end face of the coolant flow body. Also, as a method for joining members formed using an aluminum material, Patent Document 2 proposes performing laser welding.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In manufacturing a cooling device that cools an object using a liquid such as a coolant, it is conceivable to overlap a first member and a second member, both made of aluminum, and join them by laser welding. For example, it is conceivable to irradiate the overlapping portion of the first and second members with laser light from the first member side and perform laser welding. Here, when performing laser welding, it is preferable to reduce the laser output from the viewpoint of energy saving. On the other hand, if the laser output is reduced, welding defects such as insufficient welding strength between the first and second members may occur. The present invention aims to reduce the laser power required for laser welding while suppressing the occurrence of welding defects. [Means for solving the problem]

[0005] For this purpose, the welding method to which the present invention is applied is: Including plate-like portion First member and A space is formed inside through which a refrigerant flows, and located above this space flat top surface Connecting to the space in question A welding method in which a second member having a hole is superimposed on a first member and laser welding is performed by irradiating the first member with laser light, wherein the first member The plate-shaped portion After forming a thin-walled section at the outer edge that is thinner than other areas, The plate-shaped portion of the first member is aligned with the direction of refrigerant flow in the aforementioned space. The hole in the second member is connected to the first member. the plate-like portion Covered by and 、 The first member is placed on top of the upper surface of the second member such that the side surface of the first member along the outer edge of the thin-walled portion does not face the second member, and laser light is shone on the thin-walled portion from the first member side, so that the width of the weld formed across the first member and the second member by the irradiation of the laser light is smaller than the width of the thin-walled portion, and the weld is formed in a position where it does not come into contact with the outer and inner edges of the thin-walled portion. Here, the thin-walled portion can be formed on the outer edge of the first member by press working. Furthermore, the thin-walled portion can be formed such that the area irradiated with the laser light becomes flat. Furthermore, the laser beam can be irradiated such that the spot diameter of the laser beam on the surface of the first member is smaller than the width of the thin-walled portion. Furthermore, from another perspective, the welding method to which the present invention is applied is: Including a plate-like portion, the plate-like portion A first member having a thin-walled portion at its outer edge that is thinner than other regions, A space is formed inside through which the refrigerant flows, and located above this space flat top surface Connecting to the space in question With respect to the second member in which a hole is formed, The plate-shaped portion of the first member is aligned with the direction of refrigerant flow in the space, and the plate-shaped portion is used The hole is covered and the side surface of the first member along the outer edge of the thin-walled portion is superimposed on the second member so that it does not face the second member. Laser welding is performed by irradiating the thin-walled portion from the first member side at the overlapping portion of the first member and the second member such that the width of the weld formed across the first member and the second member is smaller than the width of the thin-walled portion and the weld is formed in a position where it does not come into contact with the outer and inner edges of the thin-walled portion. Furthermore, from another perspective, the structures to which the present invention applies are: Including a plate-like portion, the plate-like portion A first member having a thin-walled portion at its outer edge that is thinner than other areas, A space is formed inside through which the refrigerant flows, and located above this space flat top surface Connecting to the space in question A hole is formed, The plate-shaped portion of the first member is positioned along the direction of refrigerant flow in the space, and the plate-shaped portion is used To cover the hole The The first member is superimposed on the second member which is not facing the side surface of the first member along the outer edge of the thin-walled portion, and the welded portion which is formed in the portion where the thin-walled portion of the first member and the second member overlap, in a position that does not contact the outer and inner edges of the thin-walled portion, and is narrower than the thin-walled portion, and joins the first member and the second member. [Effects of the Invention]

[0006] According to the present invention, the laser output required for laser welding can be reduced while suppressing the occurrence of welding defects. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view of a liquid-cooled cooling device according to an embodiment. [Figure 2]This is a diagram showing the disassembled components of the liquid-cooled cooling device. [Figure 3] This is a cross-sectional view of the III-III section of FIG. 1. [Figure 4] This is a cross-sectional view of the IV-IV section of FIG. 1. [Figure 5] (a) to (b) are diagrams for explaining the configurations of the inlet joint and the outlet joint to which other forms are applied. [Figure 6] (a) to (b) are diagrams for explaining the laser welding process in the overlapping portion between the inlet joint and the device body. [Figure 7] (a) to (b) are diagrams for explaining the configurations of the inlet joint and the outlet joint to which the present embodiment is applied. [Figure 8] (a) to (b) are diagrams for explaining the laser welding process in the overlapping portion between the inlet joint and the device body.

Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view of a liquid-cooled cooling device 1 according to an embodiment. FIG. 2 is a diagram showing the disassembled components of the liquid-cooled cooling device 1. FIG. 3 is a cross-sectional view of the III-III section of FIG. 1. FIG. 4 is a cross-sectional view of the IV-IV section of FIG. 1. The liquid-cooled cooling device 1 according to the embodiment includes a device body 10 as an example of a second member through which a coolant flows inside, and a changing member 20 that changes the flow direction of the coolant flowing through the device body 10. Further, the liquid-cooled cooling device 1 includes an inlet joint 30 as an example of a first member that allows the coolant to flow from the outside to the inside of the device body 10, and an outlet joint 40 as another example of a first member that allows the coolant to flow out from the inside to the outside of the device body 10.

[0009] (Device body 10) The device body 10 is a member with a rectangular parallelepiped general shape. The device body 10 is formed using an extruded material of JIS A6063 alloy formed by extrusion, and is formed such that the extrusion direction is the longitudinal direction. Also, as shown in FIG. 1, the lengths in the longitudinal direction and the short-side direction of the device body 10 are larger than the length in the vertical direction. Note that examples of the quality grades of JIS A6063 alloy can be T1, T5, and T6. Also, other quality grades may be used, but it is desirable that the hardness of the device body 10 be 42 (HV (Vickers hardness)) or more.

[0010] Inside the device body 10, a plurality of through holes 11 penetrating from one end to the other end in the longitudinal direction are formed. In the liquid-cooled cooling device 1 according to the present embodiment, as shown in FIG. 4, six through holes 11 are formed on the front side and six through holes 11 are formed on the back side of the central portion in the short-side direction, respectively.

[0011] The six through holes 11 on the front side function as an inflow-side flow path 111 through which the coolant flowing in through the inlet joint 30 and reaching the changing member 20 circulates. Adjacent inflow-side flow paths 111 are partitioned by an inflow-side wall 111a. On the other hand, the six through holes 11 on the back side function as an outflow-side flow path 112 through which the coolant flowing in after passing through the changing member 20 and reaching the outlet joint 40 circulates. Adjacent outflow-side flow paths 112 are partitioned by an outflow-side wall 112a.

[0012] Also, in the device body 10, two spaces 12 recessed from the upper surface are formed at the central portion in the longitudinal direction. One of the two spaces 12 is an inflow-side space 121 formed to communicate with the inflow-side flow path 111, and the other is an outflow-side space 122 formed to communicate with the outflow-side flow path 112. The inflow-side space 121 is a space formed by removing the upper wall 13 and the inflow-side wall 111a, for example by cutting, and is formed by a through-hole 121a through which the upper wall 13 has passed and a lower space 121b from which the inflow-side wall 111a has been removed. In the example shown in Figure 2, the inflow-side wall 111a is completely removed from top to bottom, but it is also possible for only a portion of the upper part to be removed and the lower part to remain. The outflow side space 122 is a space formed by removing the upper wall 13 and the outflow side wall 112a, for example by cutting, and is formed by a through hole 122a through which the upper wall 13 has passed and a lower space 122b from which the outflow side wall 112a has been removed. In the example shown in Figure 2, the outflow side wall 112a is completely removed from top to bottom, but it is also possible for only a portion of the upper part to be removed and the lower part to remain. As shown in Figure 2, the through holes 121a and 122a are generally rectangular in shape.

[0013] (Modified component 20) The modification members 20 are located at both ends in the longitudinal direction of the device body 10. The modified member 20 is a rectangular parallelepiped in shape, and has a recessed portion 21 formed on its end face on the device body 10 side. The recessed portion 21 connects the inflow channel 111 and the outflow channel 112. The modified member 20 is joined by laser welding at the abutting joint, with the end face on the device body 10 side and the longitudinal end face of the device body 10 being abutted together.

[0014] For example, the modified member 20 may be formed by deep drawing a strip made of JIS A3000 series alloy of temper O. Alternatively, the modified member 20 may be formed by cutting a material made of JIS A3000 series alloy of temper H14 or JIS A1000 series aluminum of temper H14.

[0015] (Inlet joint 30) Figures 5(a) and 5(b) illustrate the configuration of the inlet joint 30 and outlet joint 40 to which this embodiment is applied. As will be described later, the inlet joint 30 and the outlet joint 40 have the same basic configuration, and in Figures 5(a) and 5(b), the reference numerals of each element constituting the inlet joint 30 are shown, and the reference numerals of each element constituting the outlet joint 40 are shown in parentheses. Figure 5(a) is a perspective view of the inlet joint 30 (outlet joint 40), and Figure 5(b) is a cross-sectional view of the VB-VB section of Figure 5(a). The inlet joint 30 has an inlet pipe 31 which is cylindrical and arranged so that its centerline direction is vertical, and a holding part 32 which is plate-shaped and extends radially outward from the lower end of the inlet pipe 31 to hold the inlet pipe 31. In the inlet joint 30 of this embodiment, when viewed from above, the inlet pipe 31 is positioned offset to the rear in the short direction from the center of the holding part 32.

[0016] The holding portion 32 has a rectangular shape when viewed from above. Furthermore, the holding portion 32 in this embodiment has a thin-walled portion 321 that is thinner in thickness (thickness in the vertical direction) compared to other areas. In this example, the thin-walled portion 321 is formed on the outer edge of the holding portion 32, and the overall shape of the thin-walled portion 321 when viewed from above is rectangular. In other words, the thickness of the outer edge of the holding portion 32 in this embodiment is thinner compared to other areas. The thickness of the thin-walled portion 321 is, for example, in the range of 30% to 80% of the thickness of other areas of the holding portion 32. Furthermore, as shown in Figures 5(a) to (b), the upper surface of the thin-walled portion 321 is flat.

[0017] The inlet joint 30 is formed integrally with the inlet pipe 31 and the holding part 32. The inlet joint 30 is formed using sheet metal of JIS A3003 alloy. Examples of JIS A3003 alloy grades include grade H12 or grade H18. Other grades are also acceptable, but it is desirable that the hardness of the holding part 32 be 35 (HV) or higher. The inlet joint 30 is formed by press-forming a sheet of JIS A3003 alloy. For example, by drawing a circular sheet of material, an inlet pipe 31 extending vertically from the center of the circular sheet is formed. Next, the circular sheet of material is cut into a rectangular shape by punching or the like to form a holding portion 32. Then, by thinning the outer edge of the holding portion 32 by press-forming to form a thin-walled portion 321, an inlet joint 30 having the shape shown in Figures 5(a) to (b) is obtained.

[0018] The inlet joint 30 is joined by laser welding with the lower end of the inlet pipe 31 facing the inlet-side space 121 of the device body 10 and the lower end surface of the holding part 32 resting on the upper surface of the device body 10 (the holding part 32 and the device body 10 are superimposed). More specifically, with the holding part 32 and the device body 10 superimposed, the inlet joint 30 is joined by a welded part 34 formed when laser light is irradiated onto the thin-walled part 321 from the holding part 32 side. The laser welding process will be explained in detail later.

[0019] (Exit joint 40) The outlet joint 40 is made of the same components as the inlet joint 30, and includes a cylindrical outlet pipe 41 positioned so that its centerline direction is vertical, and a plate-shaped holding portion 42 that extends radially outward from the lower end of the outlet pipe 41 and holds the outlet pipe 41. In the outlet joint 40 of this embodiment, when viewed from above, the outlet pipe 41 is positioned offset to the rear in the short direction from the center of the holding portion 42.

[0020] The holding portion 42 has a rectangular shape when viewed from above. Furthermore, the holding portion 42 in this embodiment has a thin-walled portion 421 that is thinner in thickness (thickness in the vertical direction) compared to other areas. In this example, the thin-walled portion 421 is formed on the outer edge of the holding portion 42, and the overall shape of the thin-walled portion 421 when viewed from above is rectangular. In other words, the thickness of the outer edge of the holding portion 42 in this embodiment is thinner compared to other areas. The thickness of the thin-walled portion 421 is, for example, in the range of 30% to 80% of the thickness of other areas of the holding portion 32. Furthermore, as shown in Figures 5(a) and 5(b), the upper surface of the thin-walled portion 421 is flat.

[0021] The outlet joint 40 is formed integrally with the outlet pipe 41 and the holding part 42. The outlet joint 40 is formed using sheet metal of JIS A3003 alloy. Examples of JIS A3003 alloy grades include grade H12 or grade H18. Other grades are also acceptable, but it is desirable that the hardness of the holding part 32 be 35 (HV) or higher. The outlet joint 40 is formed by press-forming a sheet of JIS A3003 alloy. For example, by drawing a circular sheet of material, an outlet pipe 41 extending vertically from the center of the circular sheet is formed. Next, the circular sheet is cut into a rectangular shape by punching or the like to form a holding portion 42. Then, the outer edge of the holding portion 42 is thinned by press-forming to form a thin-walled portion 421, thereby obtaining an outlet joint 40 having the shape shown in Figures 5(a) to (b).

[0022] The outlet joint 40 is joined by laser welding with the lower end of the outlet pipe 41 facing the outflow side space 122 of the device body 10 and the lower end surface of the holding part 42 resting on the upper surface of the device body 10 (the holding part 42 and the device body 10 are superimposed). More specifically, with the holding part 42 and the device body 10 superimposed, a laser beam is irradiated onto the thin-walled part 421 from the holding part 42 side to form a welded part 44, and the outlet joint 40 is joined by the welded part 44.

[0023] (Operation of liquid-cooled cooling device 1) In the liquid-cooled cooling device 1 configured as described above, the object to be cooled by the liquid-cooled cooling device 1 is placed on the upper surface of the device body 10, longitudinally outward from the area where the inlet joint 30 and outlet joint 40 are provided. An example of the object to be cooled is a battery pack 100 consisting of multiple rectangular cell units 101.

[0024] In the liquid-cooled cooling device 1, the coolant flows from the inlet pipe 31 of the inlet joint 30 into the inlet-side space 121 of the device body 10, passes through the inlet-side flow path 111, and reaches the recess 21 of the modification member 20. The coolant that reaches the recess 21 of the modification member 20 then passes through the outlet-side flow path 112 to the outlet-side space 122, and flows out from the outlet pipe 41 of the outlet joint 40. In this way, the coolant cools the battery pack 100 placed on the upper surface of the device body 10 while it flows through the inlet-side flow path 111 and the outlet-side flow path 112 of the device body 10.

[0025] (Method of manufacturing a liquid-cooled cooling device 1) The liquid-cooled cooling device 1 configured as described above is manufactured as follows. With the end faces of both longitudinal ends of the device body 10 and the end face of the modification member 20 on the device body 10 side butted together, a laser beam is continuously irradiated onto the butt joint. In this way, the modification member 20 is joined to both longitudinal ends of the device body 10 by laser welding. When a laser beam is shone onto the butt joint, a welded joint 22 (see Figure 3) is formed at approximately the same position as the butt joint.

[0026] Furthermore, prior to joining the inlet joint 30 to the device body 10, a thin-walled portion 321 is formed on the holding portion 32 of the inlet joint 30. Then, the lower end of the inlet pipe 31 of the inlet joint 30 is positioned opposite the inlet-side space 121 of the device body 10, and the lower end surface of the holding portion 32 of the inlet joint 30 is placed on the upper surface of the device body 10 (the holding portion 32 and the device body 10 are superimposed). With the holding portion 32 and the device body 10 superimposed, laser light is irradiated onto the thin-walled portion 321 formed on the holding portion 32, and laser light is irradiated around the inlet pipe 31. In this way, the inlet joint 30 is joined to the central part of the device body 10 by laser welding. When laser light is irradiated onto the thin-walled portion 321 of the holding portion 32, a welded portion 34 (see Figures 1, 3, etc.) is formed at approximately the same position as the irradiated area.

[0027] Similarly, prior to joining the outlet joint 40 to the device body 10, a thin-walled portion 321 is formed on the holding portion 32 of the outlet joint 40. Then, the lower end of the outlet pipe 41 of the outlet joint 40 is positioned opposite the outflow-side space 122 of the device body 10, and the lower end surface of the holding portion 42 of the outlet joint 40 is placed on the upper surface of the device body 10 (the holding portion 42 and the device body 10 are superimposed). With the holding portion 42 and the device body 10 superimposed, laser light is irradiated onto the thin-walled portion 421 formed on the holding portion 42, and laser light is irradiated around the outlet pipe 41. In this way, the outlet joint 40 is joined to the central part of the device body 10 by laser welding. When laser light is irradiated onto the thin-walled portion 421 of the holding portion 42, a welded portion 44 (see Figure 1) is formed at approximately the same position as the irradiated area.

[0028] (Thin part forming process) Next, the process of forming the thin-walled portion 321 and the thin-walled portion 421 on the holding portion 32 of the inlet joint 30 and the holding portion 42 of the outlet joint 40 will be described in detail. Since the inlet joint 30 and the outlet joint 40 have similar configurations, the process of forming the thin-walled portion 321 on the holding portion 32 of the inlet joint 30 will be described in detail here. As described above, the thin-walled portion 321 can be formed by press working. For example, a rectangularly cut holding portion 32 is sandwiched between a pair of molds having a predetermined shape and pressed. This forms a thin-walled portion 321 on the outer edge of the rectangular holding portion 32, which is thinner in thickness (vertical thickness) compared to other areas.

[0029] The thickness of the holding portion 32 of the entrance joint 30 is, for example, 0.9 mm to 1.2 mm. In this embodiment, press forming is performed so that the thickness of the thin-walled portion 321 is in the range of 30% to 80% of the thickness of the other areas of the holding portion 32. If the thickness of the thin-walled portion 321 is excessively thin, the strength of the thin-walled portion 321 may decrease. Also, if the difference in thickness between the thin-walled portion 321 and other areas of the holding portion 32 is small, the effect of the thin-walled portion 321, as described later, may not be fully obtained.

[0030] Here, the inlet joint 30 is formed using a plate material of JIS A3003 alloy. The holding portion 32 of the inlet joint 30 may have uneven thickness, or may have undulations or distortions depending on the condition of the plate material and the manufacturing process. When an inlet joint 30 having such a holding portion 32 is superimposed on the device body 10, a gap may occur between the holding portion 32 and the device body 10. Furthermore, when laser light is irradiated onto the superimposed portion in the laser welding process described later, the welding strength between the holding portion 32 and the device body 10 may be insufficient, resulting in welding defects. In contrast, as in this embodiment, by press-forming the holding portion 32 to form a thin-walled portion 321, uneven thickness, waviness, distortion, etc., in the thin-walled portion 321 are more easily eliminated. In other words, by forming the thin-walled portion 321, the area of ​​the holding portion 32 in which the thin-walled portion 321 is formed becomes flat. As a result, when laser light is irradiated onto the overlapping portion during the laser welding process, welding defects are less likely to occur. As will be explained in more detail later, it is preferable that the width of the thin-walled section 321 (W1 in Figure 6(a), which will be explained later) is larger than the spot diameter of the laser beam used in the laser welding process.

[0031] In this explanation, we have described a case where the inlet pipe 31 and the holding portion 32 of the inlet joint 30 are formed first, and then the thin-walled portion 321 is formed on the holding portion 32 by press working. However, the holding portion 32 having the thin-walled portion 321 and the inlet pipe 31 may be formed simultaneously by a single press working process. Furthermore, the thin-walled portion 321 may be formed by methods other than press working, such as cutting. However, from the viewpoint of eliminating the unevenness, waviness, and distortion of the thickness of the holding portion 32 described above, it is preferable to form the thin-walled portion 321 by press working.

[0032] (Laser welding process) Next, the laser welding process at the overlapping portion between the inlet joint 30 and the outlet joint 40 and the main body 10 of the device will be described in detail. Since the inlet joint 30 and the outlet joint 40 have the same configuration, the laser welding process at the overlapping portion between the inlet joint 30 (holding portion 32) and the main body 10 of the device will be described in detail here. Figures 6(a) and 6(b) illustrate the laser welding process at the overlapping section between the inlet joint 30 and the main body of the device 10. Figure 6(a) shows the state in which laser light L is irradiated onto the overlapping section, and Figure 6(b) shows the welded section 34 formed by the irradiation of laser light L. Figures 6(a) and 6(b) are cross-sectional views of the overlapping section and correspond to enlarged cross-sectional views of the liquid-cooled cooling device 1 shown in Figure 3.

[0033] When performing laser welding, laser light L is irradiated from the laser head 151 of the laser device 150 toward the overlapping portion between the entrance joint 30 and the device body 10. In this embodiment, the laser light L is irradiated toward the overlapping portion from the side of the holding portion 32. More specifically, as shown in Figure 6(a), the laser light L is irradiated toward the overlapping portion from the upper side of the thin-walled portion 321 formed on the holding portion 32. As described above, the thin-walled portion 321 is formed in a rectangular shape along the outer edge of the holding portion 32. Therefore, the laser light L is irradiated toward the overlapping portion while moving the laser head 151 along the shape of the thin-walled portion 321, or in other words, while moving the laser head 151 along the outer edge of the holding portion 32. As a result, by irradiating the thin-walled portion 321 with laser light L, a welded portion 34 is formed in a rectangular shape along the outer edge of the holding portion 32 on the overlapping portion.

[0034] Laser light L is irradiated from the laser head 151 of the laser device 150 onto the thin-walled portion 321 of the holding portion 32. The energy of the laser light L is converted into heat, causing the base material of the holding portion 32 and the device body 10, which constitute the overlapping portion, to melt, and then rapidly cool. This rapid heating and cooling causes a structural change in the welded portion 34, and the welded portion 34 is composed of a molten portion 34m that has melted and solidified, and a heat-affected zone 34h where structural changes have occurred due to the welding heat. The heat-affected zone 34h is composed of the heat-affected zone 32h of the holding portion 32 and the heat-affected zone 10h of the device body 10.

[0035] In this embodiment, a thin-walled portion 321 is formed in the holding portion 32, and by irradiating the overlapping portion with laser light L from the upper surface of the thin-walled portion 321, the intensity of the laser light (laser output) required for laser welding the overlapping portion can be reduced compared to the case where the holding portion 32 does not have a thin-walled portion 321. In other words, in order to ensure sufficient joint strength between the entrance joint 30 and the device body 10, the depth H of the welded portion 34 (molten portion 34m) in the device body 10 must be greater than or equal to a predetermined depth. In this embodiment, by irradiating the upper surface of the thin-walled portion 321 with laser light L, the distance from the upper surface of the holding portion 32 (thin-walled portion 321), which is the irradiation surface of the laser light L, to the device body 10 is reduced. As a result, even when the laser output is reduced, it becomes possible to form a welded portion 34 (molten portion 34m) of greater than or equal to a predetermined depth in the device body 10. The depth H of the welded portion 34 (molten portion 34m) can be, for example, greater than or equal to the width W3 of the molten portion 34m at the interface between the device body 10 and the holding portion 32 (thin-walled portion 321).

[0036] Furthermore, by reducing the laser output, it is possible to suppress the generation of strain caused by thermal contraction and deformation of the area irradiated with laser light L when the overlapping portion is irradiated with laser light L. This makes it possible to suppress defects such as warping of the liquid-cooled cooling device 1. Furthermore, by reducing the laser output, the generation of voids when the molten portion 34m is formed in the overlapping section can be suppressed. Furthermore, by irradiating the upper surface of the thin-walled portion 321 with laser light L, the size of the heat-affected zone 34h (especially the size of the heat-affected zone 32h) in the welded portion 34 formed in the overlapping portion can be reduced. This reduces the solidification and shrinkage associated with the formation of the heat-affected zone 34h. As a result, a decrease in the strength of the overlapping portion and welding defects can be suppressed.

[0037] In this embodiment, as shown in Figure 6(a), it is preferable to irradiate the overlapping portion with the laser beam L such that the spot diameter of the laser beam L is smaller than the width W1 of the thin-walled portion 321. Here, the width W1 of the thin-walled portion 321 is the distance between the outer edge and the inner edge of the rectangular thin-walled portion 321, and is the width of the thin-walled portion 321 in a cross-section cut by a plane perpendicular to the direction of movement of the laser head 151 that irradiates the thin-walled portion 321 with the laser beam L. The spot diameter of the laser beam L is the diameter of the irradiation area of ​​the laser beam L on the irradiation surface (in this example, the upper surface of the thin-walled portion 321) when the laser beam L is irradiated onto this irradiation surface. The spot diameter of the laser beam L varies depending on the material of the inlet joint 30 and the thickness of the thin-walled portion 321, but can be in the range of 20 μm to 80 μm, for example. Furthermore, in this embodiment, as shown in Figure 6(b), it is preferable to set the laser output, etc., so that the width W2 of the molten portion 34m on the surface of the thin-walled portion 321 is smaller than the width W1 of the thin-walled portion 321. The laser output varies depending on the material of the entrance joint 30, the thickness of the thin-walled portion 321, the spot diameter of the laser beam L, etc., but when using a fiber laser laser device 150, with a spot diameter of 50 (μm), nitrogen (N2) as the inert gas, and setting the focal point to match the material surface, the energy obtained by dividing the laser output by the laser's moving speed can be in the range of 10 J / mm to 30 J / mm.

[0038] The laser source of the laser device 150 is not particularly limited. Examples include a YAG laser, CO2 laser, fiber laser, disk laser, and semiconductor laser. Furthermore, the irradiation direction of the laser light L may be perpendicular to the surface of the holding portion 32 of the overlapping portion, or it may be inclined with respect to the perpendicular direction.

[0039] (Regarding other forms of thin-walled sections) Next, other forms of the thin-walled portion formed in the inlet joint 30 or outlet joint 40 will be described. In the example described above, the thickness of the outer edge of the holding portion 32 (holding portion 42) of the inlet joint 30 (outlet joint 40) is reduced to form a thin-walled portion 321 (thin-walled portion 421), but the invention is not limited to this. Figures 7(a) and 7(b) illustrate the configurations of the inlet joint 30 and outlet joint 40 to which other configurations are applied. In Figures 7(a) and 7(b), the reference numerals of each element constituting the inlet joint 30 are shown, and the reference numerals of each element constituting the outlet joint 40 are shown in parentheses. Figure 7(a) is a perspective view of the inlet joint 30 (outlet joint 40), and Figure 7(b) is a cross-sectional view of the VIIB-VIIB section in Figure 7(a). Figures 8(a) and 8(b) illustrate the laser welding process at the overlapping section between the inlet joint 30 and the main body of the device 10. Figure 8(a) shows the state in which laser light L is irradiated onto the overlapping section, and Figure 8(b) shows the welded section 34 formed by the irradiation of laser light L. Figures 8(a) and 8(b) are cross-sectional views of the overlapping section and correspond to enlarged cross-sectional views of the liquid-cooled cooling device 1 shown in Figure 3. Here, the same reference numerals are used for components with the same configuration as the inlet joint 30 shown in Figures 5(a)-(b), 6(a)-(b), etc., and detailed explanations are omitted.

[0040] As shown in Figures 7(a) and 7(b), the holding portion 32 of the inlet joint 30 has a groove-shaped thin-walled portion 322 that extends rectangularly along its outer edge. As shown in Figure 7(b), the cross-sectional shape of the thin-walled portion 322 is a trapezoidal shape, with the width narrowing from top to bottom and a flat bottom. In the inlet joint 30 shown in Figures 7(a) and 7(b), the thickness (vertical thickness) at the bottom of the thin-walled portion 322 is thinner than in other areas. The thin-walled portion 322 can be formed by press working, similar to the thin-walled portion 321. For example, a rectangularly cut retaining portion 32 is sandwiched between a pair of molds having a predetermined shape and pressed. This forms a groove-shaped thin-walled portion 322 on the outer edge of the rectangular retaining portion 32.

[0041] When joining the overlapping portion of the entrance joint 30 and the main body of the device 10 by laser welding, laser light L is irradiated from the laser head 151 of the laser device 150. Specifically, as shown in Figure 8(a), the laser light L is irradiated onto the overlapping portion from the upper side of the thin-walled portion 322 to the bottom surface of the thin-walled portion 322. As described above, the thin-walled portion 322 is formed in a rectangular shape along the outer edge of the holding portion 32. Therefore, the laser light L is irradiated onto the overlapping portion while moving the laser head 151 along the shape of the thin-walled portion 322. By irradiating the thin-walled portion 321 with laser light L, a welded portion 34 is formed in a rectangular shape along the outer edge of the holding portion 32 in the overlapping portion.

[0042] In the configurations shown in Figures 8(a) and 8(b), a groove-shaped thin-walled portion 322 is formed in the holding portion 32, and by irradiating the overlapping portion with laser light L from the upper surface of the thin-walled portion 322, the intensity of the laser light (laser output) required for laser welding the overlapping portion can be reduced compared to the case where the holding portion 32 does not have a thin-walled portion 322. Here, as shown in Figure 8(a), it is preferable to irradiate the overlapping portion with the laser beam L such that the spot diameter of the laser beam L is smaller than the width W4 of the bottom surface of the thin-walled portion 322. Furthermore, as shown in Figure 8(b), it is preferable to set the laser output, etc., so that the width W5 of the molten portion 34m at the bottom surface of the thin-walled portion 322 is smaller than the width W4 of the bottom surface of the thin-walled portion 322.

[0043] As described above, the laser welding method according to this embodiment is a welding method in which an inlet joint 30 (outlet joint 40), which is an example of a first member, and a device body 10, which is an example of a second member, are superimposed and laser welding is performed by irradiating laser light L from the inlet joint 30 (outlet joint 40) side. Thin-walled portions 321, 322 (thin-walled portions 421, 422) that are thinner in a predetermined area of ​​the inlet joint 30 (outlet joint 40) compared to other areas are formed, and then laser light L is irradiated onto the thin-walled portions 321, 322 (thin-walled portions 421, 422) from the inlet joint 30 (outlet joint 40) side. As a result, it is possible to reduce the laser output required to join the inlet joint 30 (outlet joint 40) and the device body 10 compared to when laser light L is not irradiated onto the thin-walled portions 321, 322 (thin-walled portions 421, 422). Furthermore, from another perspective, the laser welding method according to this embodiment involves overlapping an inlet joint 30 (outlet joint 40), which is an example of a first member having thin-walled sections 321, 322 (thin-walled sections 421, 422) that are thinner than other areas, with a device body 10, which is an example of a second member. Laser welding is then performed by irradiating the thin-walled sections 321, 322 (thin-walled sections 421, 422) from the inlet joint 30 (outlet joint 40) side at the overlapping portion of the inlet joint 30 (outlet joint 40) and the device body 10. This makes it possible to reduce the laser output required to join the inlet joint 30 (outlet joint 40) and the device body 10 compared to a case where laser light L is not irradiated onto the thin-walled sections 321, 322 (thin-walled sections 421, 422).

[0044] Furthermore, from another perspective, the structure according to this embodiment is a liquid-cooled cooling device 1 comprising: an inlet joint 30 (outlet joint 40), which is an example of a first member having thin-walled portions 321, 322 (thin-walled portions 421, 422) that are thinner than other areas; a device body 10, which is an example of a second member onto which the inlet joint 30 (outlet joint 40) is superimposed; and a welded portion 34 (welded portion 44) formed at the overlapping portion of the thin-walled portions 321, 322 (thin-walled portions 421, 422) of the inlet joint 30 (outlet joint 40) and the device body 10, which joins the inlet joint 30 (outlet joint 40) and the device body 10.

[0045] Although embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Various modifications and combinations are permitted as long as they do not contradict the spirit of the present invention. [Explanation of Symbols]

[0046] 1...Liquid-cooled cooling device, 10...Device body, 20...Modification part, 30...Inlet joint, 31...Inlet pipe, 32...Holding part, 34...Welded part, 40...Outlet joint, 41...Outlet pipe, 42...Holding part, 44...Welded part, 321, 322, 421, 422...Thin-walled part

Claims

1. A welding method comprising superimposing a first member including a plate-like portion and a second member having a space through which a refrigerant flows, and having a hole communicating with the space formed on a flat upper surface located above the space, and performing laser welding by irradiating the first member from the side, After forming a thin-walled portion on the outer edge of the plate-like portion of the first member, the hole in the second member is covered with the plate-like portion of the first member so that the plate-like portion of the first member is aligned with the direction of refrigerant flow in the space, and the first member is superimposed on the upper surface of the second member so that the side surface of the first member along the outer edge of the thin-walled portion does not face the second member, and a laser beam is irradiated onto the thin-walled portion from the first member side. A welding method in which laser light is irradiated such that the width of the weld formed across the first member and the second member by irradiation of the laser light is smaller than the width of the thin-walled portion, and the weld is formed in a position where it does not come into contact with the outer edge and inner edge of the thin-walled portion.

2. The welding method according to claim 1, characterized in that the thin-walled portion is formed on the outer edge of the first member by press working.

3. The welding method according to claim 1, characterized in that the thin-walled portion is formed such that the area irradiated with the laser light becomes a flat surface.

4. The welding method according to any one of claims 1 to 3, characterized in that the laser beam is irradiated on the surface of the first member such that the spot diameter of the laser beam on the surface of the first member is smaller than the width of the thin-walled portion.

5. A first member, which includes a plate-like portion and has a thin-walled portion on the outer edge of the plate-like portion that is thinner than other areas, is superimposed on a second member, which has a space formed inside through which a refrigerant flows and a hole formed on the flat upper surface located above the space that communicates with the space, such that the plate-like portion of the first member is aligned with the direction of refrigerant flow in the space, the hole is covered by the plate-like portion, and the side surface of the first member along the outer edge of the thin-walled portion does not face the second member. A welding method in which a laser beam is irradiated from the first member side onto the thin-walled portion at the overlapping portion of the first member and the second member, such that the width of the weld formed across the first member and the second member is smaller than the width of the thin-walled portion, and the weld is formed in a position where it does not come into contact with the outer and inner edges of the thin-walled portion.

6. A first member comprising a plate-like portion and having a thin-walled portion on the outer edge of the plate-like portion that is thinner in thickness than other regions, A space through which refrigerant flows is formed inside, a hole communicating with the space is formed on a flat upper surface located above the space, the plate-like portion of the first member is aligned with the direction of refrigerant flow in the space, and the first member is superimposed such that the plate-like portion covers the hole, and a second member is located on the side of the first member that does not face the outer edge of the thin-walled portion, A welded portion is formed in the area where the thin-walled portion of the first member and the second member overlap, in a position that does not contact the outer and inner edges of the thin-walled portion, and is narrower than the thin-walled portion, and joins the first member and the second member. A structure equipped with the following features.

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