JP2021171777A - Aluminum case and method for manufacturing aluminum case - Google Patents

Abstract

To provide an aluminum case that can suppress a blowhole that is exposed at an inner peripheral surface of a through-hole that is formed in an aluminum case, and to provide a method for manufacturing an aluminum case.SOLUTION: An aluminum case 1 includes: a junction part 13 in which a first member 11 and a second member 12, which are an aluminum alloy member formed by casting, are joined by friction stir welding; and a through-hole 17 formed across both of the first member 11 and the second member 12 while the junction part 13 is interposed therebetween. The through-hole 17 has an opening end 18 comprising a corner part 23a and round corner parts 21a, 22a along a circumferential direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to an aluminum case and a method for manufacturing an aluminum case.

In recent years, aluminum cases made of cast aluminum or its alloys have been widely used because of their advantages such as light weight, non-magnetism, and good thermal conductivity. Patent Document 1 shows a transmission case (casting case) as an example of such an aluminum case.

In the aluminum member constituting the aluminum case, casting defects such as cavities (hereinafter, also simply referred to as cavities) are likely to occur in the thick portion at the time of casting. In the casting case shown in Patent Document 1, a recessed cast portion (a lightening portion in Patent Document 1) is provided in a thick portion on the outer surface of the case in order to suppress the occurrence of cavities.

The aluminum case may be manufactured by joining a plurality of aluminum members. Patent Document 2 discloses a configuration in which aluminum plate-shaped members are joined by a friction stir welding method.

Japanese Unexamined Patent Publication No. 2005-59082 Japanese Unexamined Patent Publication No. 10-263852

In the friction stir welding method used to manufacture an aluminum case, two cast-molded aluminum members are butted against each other and the stirring rotor is brought into contact with a predetermined width (joining region) including the butted portion. The two members are agitated and joined. At this time, if the joint region is thin, when the stirring rotor is brought into contact with the joint region, the abutting portion is opened to form a gap, and internal defects are likely to occur in the joint region. Therefore, the joint region needs to be configured as a thick-walled portion, but as described above, cavities are likely to occur in the thick-walled portion. Here, in the aluminum case, a through hole may be formed in the joint region for internal ventilation, insertion of a member to be housed inside, or the like. Such a through hole is formed, for example, straddling two members. When the through hole is formed in the thick portion of the joint region, the cavities may be exposed on the inner peripheral surface (processed surface) of the through hole in the aluminum case. In the aluminum case, the through hole may receive a reaction force from the inside, so if there is a cavity on the inner peripheral surface of the through hole, stress concentration will occur in the cavity and the part around the through hole may be damaged. There is.

In view of the above circumstances, there is a demand for an aluminum case and a method for manufacturing the aluminum case, which can suppress the cavities exposed on the inner peripheral surface of the through hole formed in the aluminum case.

The characteristic configuration of the aluminum case according to the present invention is that the first member and the second member, which are aluminum alloy members formed by casting, have a joint portion joined by friction stir welding, and the joint portion is sandwiched between the first member and the second member. An aluminum case in which a through hole straddling both the first member and the second member is formed, and the open end of the through hole is a point composed of a corner portion and a rounded portion along the circumferential direction. be.

According to this configuration, the aluminum case is formed by joining the first member and the second member, and the open end of the through hole straddling both the first member and the second member across the joint portion of both members is formed. It consists of corners and rounded corners along the circumferential direction. Here, the corner portion corresponds to a right-angled portion formed by the peripheral surface of the through hole and the inner peripheral surface of the through hole. Such corner portions can be formed by processing through holes with, for example, a drill or the like. On the other hand, the rounded corner portion corresponds to a portion in which the corner portion of the open end of the through hole is rounded in an R shape in the penetrating direction of the through hole. Such a rounded corner portion can be formed by a cast portion provided at the time of casting if it is the first member and the second member formed by casting, and even after processing a through hole with a drill or the like. May remain. If a cast portion is formed during casting, the wall thickness in the vicinity of the cast portion becomes thin, and cavities are unlikely to occur. For this reason, when a through hole of the aluminum case is formed at a position close to the cast portion, a cavity is unlikely to occur in the vicinity of the cast portion, so that the cavity is suppressed from being exposed on the inner peripheral surface of the through hole. can do. Further, the rounded corners of the through holes of the aluminum case can also function as a guide portion when inserting various members into the aluminum case.

As another characteristic configuration, the corner portion straddles the first member and the second member across the joint portion, and is formed in a joint region joined by the friction stir welding, and the rounded corner portion is formed. , It is formed in a non-joint region continuous from the joint region to the first member and the second member, respectively.

According to this configuration, in the through hole formed in the aluminum case, a corner portion that can be formed by drilling with a drill or the like is formed in the joint region of the first member and the second member. The joining region is a region where the first member and the second member are joined by friction stir welding, and is a region where the rotor stirs at the time of friction stir welding. Therefore, in the first member and the second member, the portion to be the joint region needs to be thickened in order to secure the rigidity. Therefore, at the time of casting the first member and the second member, it is not possible to form a cast portion in a portion to be a joint region by friction stir welding to reduce the wall thickness. As a result, the open end of the through hole formed in the portion other than the cast portion becomes a corner portion. That is, the corner portion is formed in the joint region. On the other hand, since the non-bonded region is a region that is not affected by friction stir welding, it is not necessary to increase the wall thickness, and a cast portion can be provided in the region. Then, the open end of the cast portion can be formed with rounded corners. Therefore, the rounded corner portion of the open end of the through hole is a rounded corner portion formed in the cast portion in the non-joined region. That is, the rounded corner portion can be formed in the non-joined region. In this way, at the open end of the through hole, the corner portion is formed in the joint region and the rounded corner portion is formed in the non-joint region. It is possible to prevent the cavities from being exposed on the inner peripheral surface.

The characteristic configuration of the method for manufacturing an aluminum case according to the present invention is a casting step of forming a first member and a second member having a cast portion by casting, and the first member and the second member. A joining step of forming a joint portion by causing the first member and the second member to be joined by friction stir welding by causing a friction stir rotor to act on the contacted portion. It has a hole forming step of straddling the first member and the second member across the joint portion and forming a through hole at a position including at least a part of each of the cast portions. The through hole straddles the first member and the second member with the joint portion sandwiched between the joint region, which is a region joined by the friction stir welding, and the first member and the second member from the joint region. Each of the above has a non-bonded region which is a continuous region, and a portion of the open end of the through hole located in the non-bonded region is a point formed by the cast portion.

According to this configuration, an aluminum case having a through hole can be appropriately manufactured by performing a casting step, a joining step, and a hole forming step on the first member and the second member made of an aluminum alloy member. .. Here, the through hole straddles the first member and the second member and is formed in the joined region and the non-joined region, and the portion of the open end of the through hole located in the non-joined region is formed by the cast portion. There is. That is, the through hole formed in the aluminum case is formed in the non-joined region including a part of the cast portion. In the first member and the second member, the thickness near the cast portion is reduced, so that cavities are less likely to occur inside. Therefore, in the manufactured aluminum case, it is possible to prevent the cavities from being exposed on the inner peripheral surface of the through hole.

Another characteristic configuration is that the shape of the inner peripheral surface of the inner peripheral surface of the cast portion on the side far from the joint portion is substantially the same as the shape of the inner peripheral surface of the through hole.

According to this configuration, the shape of the inner peripheral surface of the inner peripheral surface of the cast portion on the side far from the joint is substantially the same as the shape of the inner peripheral surface of the through hole. It can be formed along the inner peripheral surface, and the hole forming step can be easily performed. Since the cast portion is a portion of the aluminum case in which the thickness of the member is thin, the strength of the through hole may decrease if there are many cast portions around the through hole. However, in this configuration, by forming the through holes along the inner peripheral surface of the cast portion, most of the cast portions of the first member and the second member can be removed by the through holes. .. As a result, the region of the cast portion remaining around the through hole in the aluminum case can be reduced. As a result, it is possible to suppress a decrease in strength of the peripheral portion of the through hole in the manufactured aluminum case.

It is a perspective view and a plan view of a main part of an aluminum case. FIG. 1 is a cross-sectional view taken along the line II-II of FIG. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. It is a main part plan view of the 1st member and the 2nd member. It is a cross-sectional view taken along the line VV of FIG. It is sectional drawing of the 1st member and 2nd member in the process of manufacturing an aluminum case. It is a top view of the main part of the 1st member and the 2nd member in the middle of manufacturing an aluminum case. It is sectional drawing of the 1st member and 2nd member in the process of manufacturing an aluminum case. It is a main part plan view of the 1st member and the 2nd member of another form. It is a main part plan view of the 1st member and the 2nd member of another form. It is sectional drawing of the 1st member and 2nd member of another form.

Hereinafter, the aluminum case and the method for manufacturing the aluminum case according to the embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of the aluminum case 1. The aluminum case 1 is formed by joining a bottomed square tubular first member 11 and a bottomed square tubular second member 12, which are aluminum alloys formed by casting. As shown in FIG. 1, in the aluminum case 1, the first member 11 and the second member 12 are joined and integrated at the joint portion 13. The first member 11 and the second member 12 are joined by friction stir welding, the first member 11 has a processed portion A1 which is thicker than the periphery, and the second member 12 is thicker than the periphery. It has a thick workpiece A2 (see FIG. 3). The joining region 14, which is a region where the rotor 3 used for friction stir welding (an example of a rotor for friction stir welding, see FIG. 6) is in contact and friction stir welded, straddles the workpiece A1 and the workpiece A2. It is formed. The processed portion A1 of the first member 11 has a joining region 14 and a non-joining region 15 which is a region other than the joining region 14. The processed portion A2 of the second member 12 has a joining region 14 and a non-joining region 16 which is a region other than the joining region 14.

As shown in FIGS. 1 to 3, the aluminum case 1 is formed with a through hole 17 formed by processing a drill or the like (not shown). The through hole 17 is formed so as to straddle the first member 11 and the second member 12 and extend from the joint region 14 to the non-joint regions 15 and 16. A corner portion 23a and rounded corner portions 21a and 22a are formed at the opening end 18 of the through hole 17. The substantially inner peripheral surface of the through hole 17 is a machined surface 23 machined by a drill or the like. The machined surface 23 is composed of straight portions 23b continuous from the corner portions 23a and the rounded corner portions 21a and 22a of the opening end 18. In the present embodiment, the cross section of the through hole 17 is circular. The cross section of the through hole 17 may be a circular shape such as an ellipse or an oval, or a square shape such as a rectangle.

The through hole 17 is provided on the side surface 2 of the aluminum case 1. The corner portion 23a of the opening end 18 of the through hole 17 straddles the first member 11 and the second member 12 with the joint portion 13 interposed therebetween, and is formed at two locations in the joint region 14 joined by friction stir welding. The rounded corner portions 21a and 22a of the open end 18 of the through hole 17 are formed in non-joining regions 15 and 16 continuous from the joining region 14 to the first member 11 and the second member 12, respectively. That is, the open end 18 of the through hole 17 is composed of two corner portions 23a and rounded corner portions 21a and 22a along the circumferential direction.

Here, the corner portion 23a corresponds to a right-angled portion formed by the upper surface 4 of the workpieces A1 and A2 around the through hole 17 in the joint region 14 and the inner peripheral surface (machined surface 23) of the through hole 17. do. Such a corner portion 23a can be formed by, for example, a drill for machining a through hole 17. On the other hand, the rounded corner portions 21a and 22a correspond to the portions where the open ends 18 of the through holes 17 in the non-joining regions 15 and 16 are rounded in an R shape. If the first member 11 and the second member 12 are aluminum alloy members formed by casting, the rounded corner portions 21a and 22a are cast portions 21 and 22 provided at the time of casting (see FIG. 3). Can be formed by. Here, the cast portions 21 and 22 are recesses formed in the thickness direction of the workpieces A1 and A2 of the first member 11 and the second member 12. By forming the cast portions 21 and 22, the wall thickness in the vicinity thereof can be reduced. Further, the shape of the inner peripheral surfaces 33b, 34b (see FIG. 4) on the side farther from the joint portion 13 of the inner peripheral surfaces 33, 34 of the cast portions 21 and 22 is substantially the same as the shape of the inner peripheral surface of the through hole 17. By forming the shape, the through hole 17 of the aluminum case 1 can be formed at a position close to the cast portions 21 and 22. Since the vicinity of the cast portions 21 and 22 is thin, it is difficult for cavities to occur, and it is possible to prevent the cavities from being exposed on the inner peripheral surface (processed surface 23) of the through hole 17 in the aluminum case 1. can.

As shown in FIG. 3, the through hole 17 is used when inserting various members 40 into the aluminum case 1 and for ventilation in the aluminum case 1. At this time, the rounded corner portions 21a and 22a can function as guide portions when inserting various members 40 into the aluminum case 1.

Further, in the aluminum case 1 of the present embodiment, a corner portion 23a capable of forming a hole by using a drill or the like in the through hole 17 is formed in the joint region 14 of the first member 11 and the second member 12. The joining region 14 is a region where the first member 11 and the second member 12 are joined by friction stir welding, and is a region where the rotor 3 (see FIG. 6) stirs during friction stir welding. Therefore, in the first member 11 and the second member 12, the portion to be the joint region 14 needs to be thickened in order to secure the rigidity. Therefore, at the time of casting the first member 11 and the second member 12, it is not possible to form cast portions 21 and 22 at the portion to be the joint region 14 by friction stir welding to reduce the wall thickness. As a result, the open end 18 of the through hole 17 formed at a portion other than the cast portions 21 and 22 becomes a corner portion 23a. That is, the corner portion 23a is formed in the joint region 14. On the other hand, the non-joining regions 15 and 16 continuous from the joining region 14 to the first member 11 and the second member 12 are regions that are not affected by friction stir welding, and therefore need not be thickened. Casting portions 21 and 22 can be provided in the region. The open ends 18A of the cast portions 21 and 22 can form rounded corner portions 21aA and 22aA (see FIGS. 5, 6 and 8). Therefore, the rounded corner portions 21a and 22a of the open end 18 of the through hole 17 are a part of the rounded corner portions 21aA and 22aA formed in the cast portions 21 and 22 in the non-joined regions 15 and 16. That is, the rounded corner portions 21a and 22a are portions after the rounded corner portions 21aA and 22aA are machined by a drill or the like in the hole forming step described later. In this way, at the open end 18 of the through hole 17, the corner portion 23a is formed in the joint region 14 and the rounded corner portions 21a and 22a are formed in the non-joint regions 15 and 16, so that the aluminum case 1 is joined. While ensuring the rigidity of the portion 13, it is possible to prevent the cavities from being exposed on the inner peripheral surface (machined surface 23) of the through hole 17.

Hereinafter, the manufacturing method of the aluminum case 1 will be described with reference to FIGS. 4 to 8. The manufacturing method of the aluminum case 1 includes a casting step, a joining step, and a hole forming step.

[Casting process]
In the casting step, the first member 11 which is made of an aluminum alloy member and has a cast portion 21 and the second member 12 which has a cast portion 22 are molded by casting. By the casting process, as shown in FIGS. 4 and 5, a cast portion 21 is formed in the machined portion A1 in the first member 11, and a cast portion 22 is formed in the machined portion A2 in the second member 12. Will be done. The cast portions 21 and 22 are formed as recesses extending in the thickness direction from the upper surface 4 of the first member 11 and the second member 12. Rounded corner portions 21aA and 22aA are formed at the open ends 18A of the cast portions 21 and 22, respectively, over the entire circumference. The rounded corner portions 21aA and 22aA are portions that are rounded from the upper surface 4 toward the bottom portions 31 and 32 of the cast portions 21 and 22 at the open ends 18A of the cast portions 21 and 22. A part of the rounded corner portions 21aA and 22aA formed at the open end 18A of the cast portions 21 and 22 becomes the rounded corner portions 21a and 22a of the open end 18 of the through hole 17.

The cast portions 21 and 22 have a symmetrical shape with respect to the contact portion B in which the first member 11 and the second member 12 are brought into contact with each other, and are formed on both sides of the bow-shaped portions 21b and 22b and the bow-shaped portions 21b and 22b. It has extension portions 21c and 22c to be formed. The extension portions 21c and 22c are formed by extending only the arc portion from the bow-shaped portions 21b and 22b. The bow-shaped portion 21b of the first member 11 and the bow-shaped portion 22b of the second member 12 are evenly separated from the contact portion B, and the distance W3 between them is larger than the width W1 of the joint region 14. On the other hand, the distance W2 between the extension portion 21c and the extension portion 22c is set to be substantially the same as the width W1 of the joint region 14. That is, the cast-out portion 21 and the cast-out portion 22 are provided with an extension portion 21c so that the distance W2 between them is substantially the same as the width W1 of the joint region 14.

As shown in FIGS. 4 and 5, the cast portions 21 and 22 are provided along the contact portion B (joint portion 13 after joining), and abut on the inner peripheral surfaces 33 and 34 thereof. There are inner peripheral surfaces 33a and 34a on the side closer to the portion B (joint portion 13 after friction stir welding) and inner peripheral surfaces 33b and 34b on the far side from the contact portion B (joint portion 13 after joining). do. Here, the inner peripheral surfaces 33b and 34b have substantially the same shape as the inner peripheral surface of the through hole 17 (dashed line) formed in the subsequent hole forming step (arc shape having substantially the same radius as the radius of the through hole 17). ) Is formed.

In the vicinity of the inner peripheral surface (machined surface 23) of the through hole 17, when the cavities are exposed from the inner peripheral surface, stress concentration occurs in the cavities, and the portion around the through hole 17 may be damaged, resulting in a thin wall. Therefore, the cast portions 21 and 22 are formed. However, if the vicinity of the contact portion B is thin, when the rotor 3 is brought into contact with the contact portion B, the contact portion B opens to form a gap, and an internal defect occurs in the joint portion 13. It is preferable to make it thick. In order to solve this contradictory problem, the cast portions 21 and 22 are composed of arch-shaped portions 21b and 22b and extension portions 21c and 22c. That is, since the inner peripheral surfaces 33b and 34b are in the vicinity of the inner peripheral surface of the through hole 17, the extension portions 21c and 22c are provided to reduce the wall thickness, and the thin wall portion is formed up to the distance W2 near the contact portion B. ing. On the other hand, since the inner peripheral surfaces 33a and 34a are portions that are removed by processing the through hole 17, there is no problem even if there is a cavity in the vicinity thereof. Therefore, the distance between the inner peripheral surfaces 33a and 34a is set to W3, and the wall thickness is made thicker than the distance W2 in the plan view shown in FIG. As a result, it is possible to prevent the contact portion B from opening and forming a gap even in the joining step by friction stir welding, which will be described later.

[Joining process]
Next, in the joining step, the first member 11 and the second member 12 are joined. In the joining step, friction stir welding is used. Friction stir welding involves butting the workpieces by sliding the rotor 3 containing the probe 3a, which is harder than the workpieces (first member 11 and second member 12), against the workpiece while rotating it. The portions (contact portion B) are joined.

As shown in FIG. 6, the probe 3a projecting from the axial center of the rotating rotor 3 is pressed against the abutting portion B of the first member 11 and the second member 12 that are abutted against each other, and remains in this pressed state. The rotor 3 is moved along the extension direction (longitudinal direction in FIG. 4) of the contact portion B. As a result, the probe 3a is embedded in the contact portion B and proceeds along the contact portion B in this embedded state. Then, the portion through which the probe 3a has passed is cured in a state where the aluminum alloy which is the material of the first member 11 and the second member 12 is agitated and kneaded and completely integrated, so that the probe 3a is other than the contact portion B. The first member 11 and the second member 12 are joined together when they are separated from the end side.

In friction stir welding, the aluminum alloy, which is the material of the first member 11 and the second member 12, is put into a plasticized state by frictional heat in the front side of the bonding region 14 in the traveling direction of the probe 3a, and the probe 3a is kneaded while stirring. It gradually shifts to the rear side in the traveling direction, loses frictional heat on the rear side in the traveling direction of the probe 3a, and rapidly cools and solidifies.

In the contact portion B, of the cast portions 21 and 22, only the portion where the extension portions 21c and 22c are formed has a distance W2 in the plan view shown in FIG. 4, and is thin, but that portion is the contact portion. Since it is extremely small with respect to the entire B and the other portions are thick, it is possible to prevent the contact portion B from opening and forming a gap even when the rotor 3 is pressed against the rotor 3.

[Hole forming process]
Next, in the hole forming step, a through hole 17 is formed at a position that straddles the first member 11 and the second member 12 with the joint portion 13 interposed therebetween and includes at least a part of each of the cast portions 21 and 22. do. Specifically, as shown in FIGS. 7 and 8, through holes shown by alternate long and short dash lines are provided for the first member 11 and the second member 12 which are joined by forming a joining mark 14a in the joining region 14. 17 (see FIG. 8) is formed. The through hole 17 is formed by processing such as a drill. As shown in FIG. 8, the through hole 17 (dashed-dotted line) is formed by leaving a part of rounded corner portions 21aA and 22aA at the opening end 18A in the cast portions 21 and 22. In FIG. 8, the radius of the through hole 17 is slightly larger than the radius of the inner peripheral surfaces 33b and 34b, but the radius of the inner peripheral surfaces 33b and 34b may be the same as the radius of the through hole 17.

As described above, the aluminum case 1 (see FIG. 1) having a through hole 17 is formed by performing a casting step, a joining step, and a hole forming step on the first member 11 and the second member 12 made of an aluminum alloy member. It can be manufactured properly. Here, the through hole 17 straddles the first member 11 and the second member 12, is formed in the joined region 14 and the non-joined region 15, 16, and is formed in the non-joined region 15, 16 of the open end 18 of the through hole 17. The location is formed by cast portions 21 and 22. That is, the through hole 17 formed in the aluminum case 1 is formed in the non-joined regions 15 and 16 in the region including a part of the cast portions 21 and 22. In the first member 11 and the second member 12, the thickness of the cast portions 21 and 22 is reduced, so that cavities are less likely to occur inside. Therefore, it is possible to prevent the cavities from being exposed on the inner peripheral surface (processed surface 23) of the through hole 17.

Further, in the present embodiment, the inner peripheral surfaces 33b and 34b of the cast portions 21 and 22 in the casting step have substantially the same shape as the inner peripheral surface of the through hole 17 formed in the hole forming step (through hole 17). It is formed in an arc shape with almost the same radius as the radius of. Therefore, in the hole forming step, the through hole 17 can be formed along the inner peripheral surfaces 33b and 34b of the cast portions 21 and 22, and the through hole 17 can be formed. Since the cast parts 21 and 22 are thin parts in the aluminum case 1, if there are many cast parts 21 and 22 around the through holes 17, the peripheral parts of the through holes 17 in the aluminum case 1 The strength of the aluminum may decrease. However, in this configuration, by forming the through holes 17 along the inner peripheral surfaces 33b and 34b of the cast portions 21 and 22, the cast portions 21 and 22 of the first member 11 and the second member 12 are formed. Can remove most of the aluminum case 1 through the through holes 17. As a result, the region of the cast portions 21 and 22 remaining around the through hole 17 in the aluminum case 1 can be reduced. As a result, it is possible to suppress a decrease in strength of the peripheral portion of the through hole 17 in the manufactured aluminum case 1.

[Another Embodiment]
(1) In the above embodiment, an example is shown in which the cast portions 21 and 22 formed on the first member 11 and the second member 12 are composed of a bow-shaped portion 21b and an extension portion 21c. As shown in FIG. 9, each of the cast portions 21 and 22 may have a bow shape. In the example shown in FIG. 9, the distance W2 between the cast portion 21 and the cast portion 22 is constant in the direction along the contact portion B, and is equal to the width W1 of the joint region 14. As shown in FIG. 10, each of the cast portions 21 and 22 may have an arc shape. In the example shown in FIG. 10, the distance W2 between both ends of the arcuate cast portion 21 of the first member 11 and both ends of the cast portion 22 of the second member 12 facing the cast portion 21 is the distance W2 of the joint region 14. Equal to width W1. Also in the cast portions 21 and 22 shown in FIGS. 9 and 10, the shapes of the inner peripheral surfaces 33b and 34b on the inner peripheral surfaces 33 and 34 of the cast portions 21 and 22 far from the joint portion 13 are through holes. The shape is substantially the same as the shape of the inner peripheral surface of 17. Although not shown, the cast portions 21 and 22 have inner peripheral surfaces 33a and 34a on the side close to the joint portion 13 so that the central portion is close to the joint portion 13 in addition to both end sides of the arc portion shown in FIG. In addition, the central portion of the inner peripheral surfaces 33a and 34a may be formed by recesses facing the joint portion 13.

(2) In the above embodiment, as shown in FIG. 5, the cast portions 21 and 22 are formed only on the front surface side (side surface 2 side) of the aluminum case 1 (first member 11 and second member 12). An example is shown. However, as shown in FIG. 11, the cast portions 21 and 22 may be provided on both sides of the first member 11 and the second member 12. Further, although not shown, the cast portions 21 and 22 may be formed only on the back surface side (opposite side of the side surface 2) of the first member 11 and the second member 12.

The present invention can be widely used in an aluminum case and a method for manufacturing an aluminum case.

1: Aluminum case 2: Side surface 11: First member 12: Second member 13: Joint portion 14: Joint region 15, 16: Non-joint region 17: Through hole 18: Open end 21 and 22: Cast portions 21a, 22a : Rounded corner 23: Processed surface (inner peripheral surface)
23a: Corner portion 23b: Straight portion 33, 34: Inner peripheral surfaces A1, A2: Processed portion B: Contact portion W1: Width of joint region W2: Distance between two cast portions

Claims (4)

The first member and the second member, which are aluminum alloy members formed by casting, have a joint portion joined by friction stir welding, and both the first member and the second member sandwich the joint portion. It is an aluminum case with a through hole that straddles the
The open end of the through hole is an aluminum case composed of a corner portion and a rounded corner portion along the circumferential direction. The corner portion straddles the first member and the second member with the joint portion interposed therebetween, and is formed in a joint region joined by the friction stir welding.
The aluminum case according to claim 1, wherein the rounded corner portion is formed in a non-joint region continuous from the joint region to the first member and the second member, respectively. A casting process in which a first member and a second member, which are made of an aluminum alloy member and have a cast portion, are formed by casting.
The first member and the second member are brought into contact with each other, and a friction stir rotor is allowed to act on the contacted portion to join the first member and the second member by friction stir welding. The joining process to form the joint and
It has a hole forming step of straddling the first member and the second member across the joint portion and forming a through hole at a position including at least a part of each of the cast portions.
The through hole straddles the first member and the second member with the joint portion sandwiched between the joint region, which is a region joined by the friction stir welding, and the first member and the second member from the joint region. Each member has a non-junction region, which is a continuous region,
A method for manufacturing an aluminum case in which a portion of the open end of the through hole located in the non-joining region is formed by the cast portion. The method for manufacturing an aluminum case according to claim 3, wherein the shape of the inner peripheral surface of the inner peripheral surface of the cast portion on the side far from the joint portion is substantially the same as the shape of the inner peripheral surface of the through hole. ..

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