JP2017024029A - Different material structural member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a different material structural member that can joint an aluminum material to a steel material at high-mechanical strength and readily connected to other members.SOLUTION: The different material structural member 100 includes: the aluminum material 11 constituted of aluminum or an aluminum alloy; the steel material 13; and a joint part 15 for jointing the aluminum material to the steel material. The joint part 15 includes an insert casting part 17 where the aluminum material 11 and the steel material 13 are integrally fixed by insert casting with a molten aluminum alloy.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dissimilar material structural member in which dissimilar materials are joined to each other.

  As a method for producing a dissimilar material structure member in which dissimilar materials such as dissimilar joint structures are joined together, a method is known in which a steel material that is one material is cast with an aluminum alloy that is the other material (Patent Documents 1 to 3). 3). In this kind of dissimilar material structural member, an anchor is formed by filling and solidifying a molten aluminum alloy in a hole formed in a steel material at the time of casting a cast. This anchor increases the bonding strength between different materials.

  Patent Document 1 describes a method for joining dissimilar metal products in which products made of dissimilar metals having relatively different melting points such as steel and aluminum are joined together. In this joining method, a part of a joining material is cast in advance with a cast metal material, so that the cast metal material and the joining material are integrated to produce a joining member A made of different metals. The joining member A is joined to the joining member B made of a metal material having substantially the same melting point as the joining material via the joining material.

  Patent Document 2 describes that an anchor hole of a dissimilar joint structure is formed in a burring hole, and the diameter of the anchor hole is set small until the same tensile strength as in the case of a simple hole is obtained.

  Patent Document 3 describes a dissimilar joint structure in which a steel plate casting fitting is cast with an aluminum casting material, and the steel plate casting fitting is welded to a steel plate joining member. The cast metal fitting of the steel plate is formed of a high-tensile steel plate having a high tensile strength, and an anchor hole for mechanically joining the cast aluminum material is formed. Further, it is described that the surface of the high-tensile steel plate is subjected to a surface treatment that makes the cast aluminum material and the steel plate surface of the cast steel fitting of the steel plate non-contact.

JP 2006-312192 A JP 2010-214454 A JP 2011-235334 A

  However, although Patent Documents 1 to 3 described above are techniques for connecting different materials of an aluminum alloy material and a steel material, a steel material is used as an insert member, and the insert member is cast with an aluminum alloy material. Therefore, the aluminum alloy material is limited to a cast material (casting, die-cast material), and the tensile strength, elongation, and the like are limited as compared with the aluminum alloy expanded material. In addition, there is a problem that the cast material is difficult to weld, and when joining the dissimilar material structural member to another member, the joining method is limited.

  This invention is made | formed in view of the said matter, The objective is to provide the dissimilar-material structural member which can be joined to aluminum material and steel material with high mechanical strength, and can be easily connected with another member.

The present invention has the following configuration.
(1) A dissimilar material structural member comprising an aluminum material made of aluminum or an aluminum alloy, a steel material, and a joint portion for joining the aluminum material and the steel material,
The said joint part has a cast-in part where the said aluminum material and the said steel material are integrally cast with the aluminum alloy molten metal, and are fixed, The different-materials structural member characterized by the above-mentioned.
(2) The dissimilar material structural member according to (1), wherein the aluminum material is an aluminum alloy wrought material.
(3) The dissimilar material structural member according to (1) or (2), wherein a through-hole through which the molten aluminum alloy flows is formed in at least one of the aluminum material and the steel material.
(4) The aluminum material and the steel material are arranged to overlap,
The through hole is formed in both the aluminum material and the steel material,
The dissimilar material structural member according to (3), wherein the hole positions of the through holes of the aluminum material and the steel material coincide with each other in the overlapping direction.
(5) The dissimilar material structural member according to any one of (1) to (4), wherein the aluminum material and the steel material are disposed with a gap between the aluminum material and the steel material.
(6) The dissimilar material structural member according to (5), wherein a spacer that forms the gap is provided between the aluminum material and the steel material.

  According to the present invention, the aluminum material and the steel material can be joined with high mechanical strength, and can be easily connected to other members.

It is a figure for demonstrating embodiment of this invention, and is a perspective view of the dissimilar material structural member of a 1st structural example. It is the sectional view on the AA line of FIG. It is a perspective view of the dissimilar material structural member of the 2nd example of composition. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is a perspective view of the dissimilar material structural member of the 3rd example of composition. It is CC sectional view taken on the line of FIG. It is a perspective view of the dissimilar material structural member of the 4th example of composition. It is the DD sectional view taken on the line of FIG. It is a perspective view of the dissimilar material structural member of the 5th example of composition. FIG. 10 is a plan view of the dissimilar material structural member shown in FIG. 9. It is the EE sectional view taken on the line of FIG. It is a perspective view of the dissimilar material structural member of the 6th example of composition. It is a top view of the dissimilar material structural member shown in FIG. It is the FF sectional view taken on the line of FIG. It is a perspective view of the dissimilar material structural member of the 6th example of composition. It is a top view of the dissimilar material structure member shown in FIG. It is the GG sectional view taken on the line of FIG. It is a perspective view of the dissimilar material structural member of the 8th example of composition. It is a top view of the dissimilar material structural member shown in FIG. It is the HH sectional view taken on the line of FIG. It is sectional drawing which shows the other spacer which forms a height direction clearance gap between an aluminum material and steel materials. It is a perspective view of the dissimilar material structure member of the 9th structural example. It is a perspective view which shows the frame | skeleton member before casting of a different material structural member. It is the II sectional view taken on the line of FIG. It is a top view of the dissimilar material structure member shown in FIG. It is the JJ sectional view taken on the line of FIG. It is a perspective view of the front sub-frame for motor vehicles.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First configuration example>
FIG. 1 is a diagram for explaining an embodiment of the present invention, and is a perspective view of a dissimilar material structural member of a first configuration example, and FIG. 2 is a cross-sectional view taken along line AA of FIG.

  The dissimilar material structural member 100 includes a plate-shaped aluminum material 11 made of aluminum or an aluminum alloy, a plate-shaped steel material 13, and a joint portion 15 that joins the aluminum material 11 and the steel material 13. The joint portion 15 includes a cast-in portion 17 that is fixed by integrally casting the aluminum material 11 and the steel material 13 with molten aluminum alloy. The aluminum material 11 and the steel material 13 of this structure are arrange | positioned along one axis | shaft, and are fixed in the state which faced | matched the end surfaces of both the end parts 11a and 13a in the axial direction.

  In this specification, the longitudinal direction of the aluminum material 11 and the steel material 13 which are longitudinal materials is referred to as the axial direction, the thickness direction of the longitudinal materials is referred to as the height direction, and the direction perpendicular to the longitudinal direction and the thickness direction is referred to as the width direction. .

  The aluminum material 11 can be a rolled material, an extruded material, a forged material, an aluminum alloy stretched material such as an aluminum clad material, or pure aluminum, and a plate thickness of 1.2 mm to 3.0 mm can be adopted. For example, JIS standard 6000 series, 5000 series, 7000 series, 2000 series, 3000 series aluminum alloy materials can be used.

  The steel material 13 can be a bare material, a galvanized steel plate, an aluminized steel plate, or the like, and can be a high strength steel having a tensile strength of 270 to 980 MPa and a thickness of 0.8 mm to 2.4 mm.

  The cast-in part 17 is an aluminum alloy casting AC4C, AC4CH, AC2B (JIS H 5202) or ADC12 (JIS H 5302), and is formed so as to cover the entire circumference of the aluminum material 11 and the steel material 13 in a cross section orthogonal to the axial direction. Is done. Further, the cast-in part 17 covers the one end parts 11 a and 13 a of the aluminum material 11 and the steel material 13, and the other end parts 11 b and 13 b opposite to the one end parts 11 a and 13 a are exposed to the outside of the cast-in part 17. ing.

  The other end portion 11b of the aluminum material 11 exposed to the outside of the cast-in portion 17 and the other end portion 13b of the steel material 13 are joined portions subjected to machining such as cutting, grinding, drilling, or joined by welding. And is joined to another member (not shown).

  According to the dissimilar material structural member 100 of this configuration, since the aluminum material 11 and the steel material 13 are joined together in the axial direction, the positioning of the aluminum material 11 and the steel material 13 is simplified. And when the aluminum material 11 is comprised with an aluminum alloy extending | stretching material, compared with an aluminum cast material, tensile strength is high, elongation becomes large, and it can improve mechanical strength. Moreover, high material quality without defects (such as sinks and nests) and high dimensional accuracy can be realized, and the dissimilar material structural member 100 can be joined to other members with high strength and high accuracy.

  That is, the aluminum material 11 can be cast in a state in which the other end portion 11b is previously machined into a desired shape. In that case, the dissimilar material structural member 100 after the cast-in joining can be directly joined to another member without post-processing. For example, if a bolt hole or a rivet hole is formed in the other end portion 11b, it can be easily fastened to another member on the other side. Moreover, if the other end part 11b of the aluminum material 11 is processed in advance as a welded part, it can be welded to other members as it is after the cast-in joining, so that the joining process does not become complicated.

  In the illustrated example, the end surfaces of the one end portions 11a and 13a of the aluminum material 11 and the steel material 13 have an axially vertical surface, but the end surface shapes of the one end portions 11a and 13a are not limited thereto. For example, the end surfaces of the one end portions 11a and 13a may have other forms such as a slope inclined from the axial direction, a slope inclined from the height direction, or an uneven surface engaging each other.

<Second configuration example>
FIG. 3 is a perspective view of the dissimilar material structural member of the second configuration example, and FIG. 4 is a cross-sectional view taken along line BB of FIG. In the following description, the same members or corresponding members are given the same reference numerals, and the description thereof is simplified or omitted.

  In the dissimilar material structural member 110 of this configuration, the aluminum material 11 and the steel material 13 are joined in a state of overlapping and contacting each other in the height direction. As shown in FIG. 4, the region where the aluminum material 11 and the steel material 13 overlap is a region W at the axial center of the cast-in portion 17, and the respective one end portions 11 a and 13 a are disposed inside the cast-in portion 17. Is done.

  According to the dissimilar material structural member 110 having this configuration, the aluminum material 11 and the steel material 13 are overlapped with each other in contact with each other. Therefore, the parallelism of both members can be obtained easily. Therefore, positioning at the time of casting of a cast hole becomes easy.

  In addition, in the example of illustration, although the opposing surface of the one end parts 11a and 13a of the aluminum material 11 and the steel material 13 has shown the form contact | abutted by flat surfaces, the opposing surface shape of the one end parts 11a and 13a is not restricted to this. . Instead of a flat surface, the opposing surfaces of the one end portions 11a and 13a may have other forms such as an inclined surface whose thickness changes along the axial direction or the width direction, and an uneven surface that engages with each other.

<Third configuration example>
FIG. 5 is a perspective view of the dissimilar material structural member of the third configuration example, and FIG. 6 is a cross-sectional view taken along the line CC of FIG.
In the dissimilar material structural member 120 of this configuration, the aluminum material 11 and the steel material 13 are arranged along one axis, and a predetermined axial gap Ca is provided between the one end portion 11a of the aluminum material 11 and the one end portion 13a of the steel material 13. Provided. That is, as shown in FIG. 6, the aluminum material 11 and the steel material 13 are joined with an axial gap Ca inside the cast-in part 17 without abutting each other.

  According to the dissimilar material structural member 120 of this configuration, both the one end portions 11a and 13a are cast with the predetermined gap Ca in the axial direction. That is, at the time of casting of the cast hole, the molten aluminum alloy flows in the axial gap Ca between the aluminum material 11 and the steel material 13, and the aluminum alloy cast material is reliably filled in the axial gap Ca.

  As a result, the aluminum material 11 and the steel material 13 increase the surface area in the cast-in part 17, that is, the area contributing to joining, and the joint strength between the aluminum material 11, the steel material 13, and the cast-in part 17 is improved. To do. Further, since there is an axial gap Ca between the aluminum material 11 and the steel material 13, an unintended gap (defect) does not occur as compared with the case where the aluminum material 11 and the steel material 13 are brought into contact with each other. . As a result, the overall strength of the dissimilar material structural member 120 can be improved.

  In addition, the end surface of the end portions 11a and 13a of the aluminum material 11 and the steel material 13 may be changed from a flat surface to an uneven surface to further increase the contact area with the cast-in portion 17. In that case, the joint strength between the aluminum material 11 and the steel material 13 can be further improved.

<Fourth configuration example>
FIG. 7 is a perspective view of the dissimilar material structural member of the fourth configuration example, and FIG. 8 is a sectional view taken along the line DD of FIG.
As shown in FIG. 7, the dissimilar material structural member 130 of this configuration includes the aluminum material 11 and the steel material 13 that are spaced apart from each other in the height direction from the state shown in FIG. 4. That is, as shown in FIG. 8, the aluminum material 11 and the steel material 13 are joined with a gap Cb in the height direction inside the cast-in part 17 without contacting each other.

  A region where the aluminum material 11 and the steel material 13 overlap in the height direction is a region W at the center in the axial direction of the cast-in portion 17, and the respective one end portions 11 a and 13 a are disposed inside the cast-in portion 17.

  According to the dissimilar material structural member 130 of this configuration, both the one end portions 11a and 13a are cast with the predetermined height direction gap Cb in the height direction. The molten aluminum alloy flows in the gap Cb during casting of the cast aluminum due to the presence of the height direction gap Cb between the aluminum material 11 and the steel material 13, and the gap Cb is reliably filled with the aluminum alloy cast material. Is done.

  Therefore, the aluminum material 11 and the steel material 13 increase the surface area in the cast-in part 17, that is, the area contributing to the joining, and the joint strength among the aluminum material 11, the steel material 13, and the cast-in part 17 is improved. . As a result, the overall strength of the dissimilar material structural member 130 can be improved.

  The facing surfaces 11c and 13c on the one end portions 11a and 13a side of the aluminum material 11 and the steel material 13 may be changed from a flat surface to an uneven surface or the like to further increase the contact area with the cast-in portion 17. In that case, the bonding strength can be further improved.

<Fifth configuration example>
9 is a perspective view of the dissimilar material structure member of the fifth configuration example, FIG. 10 is a plan view of the dissimilar material structure member shown in FIG. 9, and FIG. 11 is a cross-sectional view taken along line EE of FIG.
The dissimilar material structural member 140 of this structure is the same structure as the dissimilar material structural member 120 except that the through hole 19 in which the molten aluminum alloy flows is formed in the steel material 13 of the dissimilar material structural member 120 shown in FIG.

  In the steel material 13, at least one through-hole 19 (three places in the illustrated example) penetrating in the height direction is formed on the one end 13 a side in the cast-in part 17. The molten aluminum alloy flows into the through-hole 19 of the steel material 13 when casting the cast-in, and the through-hole 19 is reliably filled with the aluminum alloy cast material.

  As a result, the cast-in portions 17 formed on the front and back surfaces of the steel material 13 are connected to each other through the through hole 19. By filling the through-hole 19 with the aluminum alloy casting material, the bonding strength between the steel material 13 and the cast-in part 17 is improved, and the mechanical strength such as the tensile strength of the dissimilar material structural member 140 is increased.

  The optimal joint strength can be obtained by appropriately adjusting the number of the through-holes 19, the arrangement location, and the hole diameter φds according to the intended use and application site of the dissimilar material structural member 140.

<Sixth configuration example>
12 is a perspective view of the dissimilar material structure member of the sixth configuration example, FIG. 13 is a plan view of the dissimilar material structure member shown in FIG. 12, and FIG. 14 is a sectional view taken along line FF in FIG.
The dissimilar material structural member 150 of this configuration is the same as the dissimilar material structural member 140 except that the aluminum material 11 of the dissimilar material structural member 140 shown in FIG. 9 has the through holes 21 through which the molten aluminum alloy flows.

  In the aluminum material 11, at least one through-hole 21 (three places in the illustrated example) penetrating in the height direction is formed on the one end 11 a side in the cast-in part 17. The molten aluminum alloy flows into the through hole 21 of the aluminum material 11 during casting of the cast-in, and the aluminum alloy cast material is surely filled into the through hole 21.

  By filling the aluminum alloy casting material into the through holes 19 and 21, the cast parts 17 formed on the front and back surfaces of the aluminum material 11 and the steel material 13 are connected to each other through the through holes 19 and 21. . Thereby, the joining strength of the aluminum material 11 and the steel material 13 and the cast-in part 17 is improved, and the mechanical strength such as the tensile strength of the dissimilar material structural member 150 is further increased.

  The number of the through holes 19 and 21, the arrangement location, the hole diameter φds of the through hole 19, and the hole diameter φda of the through hole 21 are appropriately adjusted according to the use application and application site of the dissimilar material structural member 150, so Can be obtained. The above is the same for each of the following configuration examples.

<Seventh configuration example>
15 is a perspective view of the dissimilar material structure member of the sixth configuration example, FIG. 16 is a plan view of the dissimilar material structure member shown in FIG. 15, and FIG. 17 is a sectional view taken along the line GG of FIG.
In the dissimilar material structural member 160 of this configuration, the through hole 19 through which the molten aluminum alloy flows is formed in the steel material 13 of the dissimilar material structural member 130 shown in FIG. 7, and the through hole 21 through which the molten aluminum alloy flows is formed in the aluminum material 11. Except for this, the structure is the same as that of the dissimilar material structural member 130.

  According to the dissimilar material structural member 160 of this configuration, the cast aluminum parts 17 are formed in the front and back surfaces of the aluminum material 11 and the steel material 13 by filling the through holes 19 and 21 with the aluminum alloy cast material. The front and back are connected through the through holes 19 and 21. Thereby, the joining strength of the aluminum material 11 and the steel material 13 and the cast-in part 17 is further improved, and the mechanical strength such as the tensile strength of the dissimilar material structural member 150 is further increased.

<Eighth configuration example>
18 is a perspective view of the dissimilar material structure member of the eighth configuration example, FIG. 19 is a plan view of the dissimilar material structure member shown in FIG. 18, and FIG. 20 is a cross-sectional view taken along line HH in FIG.

  In the dissimilar material structural member 170 of this configuration, a through hole 19 through which the molten aluminum alloy flows is formed in the steel material 13 of the dissimilar material structural member 130 shown in FIG. The hole positions of the through hole 21 of the aluminum material 11 and the through hole 19 of the steel material 13 coincide with the overlapping direction of the aluminum material 11 and the steel material 13. Further, a gap is formed between the aluminum material 11 and the steel material 13 in the height direction. This height direction gap is provided on the facing surface 11 c of the aluminum material 11, and is formed by a protrusion 23 that protrudes toward the steel material 13. Other configurations are the same as those of the dissimilar material structural member 130.

  The protrusion 23 functions as a spacer, and the height direction gap between the aluminum material 11 and the steel material 13 can be arbitrarily set by adjusting the protrusion height. The protrusion 23 may be provided on the steel material 13 side in addition to the aluminum material 11 side. As shown in FIG. 19, in this configuration example, the protrusions 23 are provided at three locations. However, the number of the protrusions 23, the location of the protrusions 23, the size and the height of the protrusions 23 are different depending It can be set accordingly. Further, when the aluminum material 11 or the steel material 13 is a thin plate, the protrusion 23 can be easily processed by forming it by sheet metal processing such as bending or extrusion.

  Further, the protrusion 23 may be a metal fitting embedded in at least one of the aluminum material 11 or the steel material 13. If the protruding height of the screw mechanism or the like can be adjusted arbitrarily, the metal fitting can freely and easily change the height direction gap between the aluminum material 11 and the steel material 13, and there is no need to change the design. .

  The protrusion 23 may be provided separately from the aluminum material 11 and the steel material 13 in addition to being provided integrally with the aluminum material 11 or the steel material 13. FIG. 21 is a cross-sectional view showing another spacer that forms a gap in the height direction between the aluminum material 11 and the steel material 13.

  A spacer 25 shown in FIG. 21 is formed of a member separate from the aluminum material 11 and the steel material 13, and is interposed between the aluminum material 11 and the steel material 13. Specific examples of the spacer 25 include rivets and pins, or nuts and washers that engage with bolts that penetrate the aluminum material 11 and the steel material 13.

  The spacer 25 is preferably made of a material having a melting point lower than that of the aluminum alloy casting that forms the cast-in part 17. In that case, the spacer 25 in which the gap between the aluminum material 11 and the steel material 13 is set is melted by the molten aluminum alloy at the time of casting, and the position of the spacer 25 is also filled with the aluminum alloy casting. Therefore, the inside of the cast-in part 17 is uniformly filled with the aluminum alloy casting, and no extra space (defect) is generated. As a result, high bonding strength can be maintained.

  Further, by providing the through hole 21 of the aluminum material 11 and the through hole 19 of the steel material 13 at a position that coincides with the overlapping direction of the aluminum material 11 and the steel material 13, it is possible to simplify the inspection after casting the cast-in. . That is, when inspecting whether or not each of the through holes 19 and 21 is filled with an aluminum alloy casting, the inside of the through holes 19 and 21 is subjected to a nondestructive inspection such as an ultrasonic flaw detection test in the overlapping direction. Can be inspected at once. Therefore, the number of inspection points can be reduced, and the performance of the dissimilar material structural member can be easily evaluated.

<Ninth configuration example>
Next, an example in which the above-described dissimilar material structural member is applied to an automobile frame member will be described.
22 is a perspective view of the dissimilar material structural member of the ninth configuration example, FIG. 23 is a perspective view of the skeleton member before casting of the dissimilar material structural member, FIG. 24 is a cross-sectional view taken along the line II of FIG. 24 is a plan view of the dissimilar material structural member shown in FIG.

  As shown in FIG. 22, the dissimilar material structural member 180 of the present configuration example is a skeleton member 31 in which an aluminum material 11 that is two types of plate materials different from each other and each end of a steel material 13 are overlapped with a gap. And the above-mentioned cast-in part 17 formed by casting in the area | region where each board | plate material was piled up is provided. The cast-in part 17 becomes a joint part 15 that joins the aluminum material 11 and the steel material 13.

  As shown in FIG. 23, the steel material 13 is a hat-shaped panel member having a substantially inverted U-shaped cross section, and the flanges 33 are formed on both sides in the width direction (X direction). The aluminum material 11 is a hat-shaped panel member having a substantially inverted U-shaped cross section that is slightly larger than the steel material 13, and the flange portions 35 are formed on both sides in the width direction (X direction). The aluminum material 11 is arranged so that the flange portion 35 is spaced apart from the flange portion 33 of the steel material 13 by a predetermined distance in the height direction and covers a part of the outer side of the steel material 13.

  That is, as shown in FIG. 24, one end 11a in the axial direction (Y direction) of the aluminum material 11 and one end 13a in the axial direction (Y direction) of the steel material 13 are the same as the aluminum material 11 and the steel material shown in FIG. 13 are overlapped with each other with a gap Cc.

  The gap Cc between the aluminum material 11 and the steel material 13 is formed by a protrusion 23A provided on the aluminum material 11 in this configuration example. The protrusion 23A is provided around a through hole (a through hole 21A on the steel material 13 side and a through hole 19A on the aluminum material 11 side) that penetrates the aluminum material 11 and the steel material 13, and the aluminum material 11 has an inverted U shape. It can be molded simultaneously with press molding.

  In addition to the protrusion 23A, the gap Cc may be formed by arranging a plurality of rivets between the aluminum material 11 and the steel material 13 and using these rivets. As a fixing method using rivets, for example, methods disclosed in Japanese Patent Application Laid-Open Nos. 7-214338 and 2010-207898 can be appropriately used.

  As shown in FIGS. 23 to 25, the aluminum material 11 and the steel material 13 are provided with the projections 23A described above on the flange portions 35, 33, the top surface portions 37, 39, and the side surface portions 41, 43 connecting them. At the same time, through holes 21A and 19A are formed. In addition to the position of the protrusion 23A, a plurality of other through holes 21B and 19B are formed. These through-holes 19A, 19B, 21A, and 21B serve as a flow path for the molten aluminum alloy when casting the cast-in.

  At the time of casting, the skeleton member 31 in which the aluminum material 11 and the steel material 13 are joined is set in a molding die (not shown) and defined in the overlapping region W of the aluminum material 11 and the steel material 13. The molten aluminum alloy is supplied to the cavity.

  Although not shown, the molding die has an outer frame body and a core inserted into the outer frame body. The skeletal member 31 is set between the inner peripheral surface of the outer frame and the core, and the cast aluminum part 17 shown in FIG. 22 is formed by flowing and filling the molten aluminum alloy into the cavity. .

  26 is a cross-sectional view taken along line JJ in FIG. As shown in FIG. 26, the cavity of the molding die is composed of a plurality of gap spaces defined around the aluminum material 11 and the steel material 13. That is, the gap space CB1 between the inner peripheral surface of the outer frame body of the molding die and the aluminum material 11, the gap space CB2 between the aluminum material 11 and the steel material 13, and the axial direction (Y direction) inside the steel material 13 ) And the gap CB3 formed between the outer peripheral surface of the core inserted along the steel material 13 and the steel material 13, and the gap space CB4 between the inner peripheral surface of the outer frame body of the molding die and the outer peripheral surface of the core. Including. These gap spaces CB <b> 1 to CB <b> 4 are filled with the molten aluminum alloy, and a cast-in part 17 is formed.

  As shown in FIG. 22, the dissimilar material structural member 180 after casting of the cast-in part is formed with a cast-in part 17 covering the end face of the one end part 11 a of the aluminum material 11 and the end face of the one end part 13 a of the steel material 13.

  As shown in FIG. 26, the molten aluminum alloy is also filled in the through holes 19A (19B) and 21A (21B). The aluminum alloy cast material filled in the through holes 19A, 19B, 21A, and 21B functions as an engagement portion between the aluminum material 11 and the steel material 13, and is difficult to come out from the hole. Moreover, the aluminum alloy casting material filled in each of the gap spaces CB1 to CB4 is connected to the cast-in portion 17 material by the engagement portion. For this reason, the whole casting part 17, the aluminum material 11, and the steel material 13 are integrated. By these actions, the rigidity and load resistance of the dissimilar material structural member 180 can be improved without increasing the weight.

  Further, end surfaces of the one end portions 11 a and 13 a of the aluminum material 11 and the steel material 13 are covered with the cast-in portion 17. Therefore, the cast-in part 17 is protected from moisture ingress, and rust, corrosion, and electrolytic corrosion are less likely to occur. A resin film may be formed at least at the boundary between the steel material 13 and the cast-in part 17 by applying an adhesive, applying a resin tape, or the like. Thereby, the electric corrosion produced by the electric potential difference of the cast-in part 17 and the steel material 13 can be prevented reliably.

  The surface of at least the overlapping region W of the aluminum material 11 and the steel material 13 may be either a smooth surface or a roughened surface. When the surface is roughened, the bonding strength with the aluminum alloy can be further increased. Examples of the roughening method include blasting, etching, brush polishing, and cutting. Since the roughening treatment removes oxides, organic substances, and the like that cause casting defects, casting defects can be prevented. Further, the overlapping region W may be formed by an embossed surface. By filling the embossed gap with the aluminum alloy cast material, the aluminum material 11 and the steel material 13 can be joined to each other with improved load resistance in the longitudinal direction.

  The thickness of the aluminum alloy cast material filled between the aluminum material 11 and the steel material 13 is the thinnest part from the viewpoint of the fluidity of the molten aluminum alloy at the time of casting and the strength of the composite member. The thickness is preferably about 1.8 to 3 mm.

  According to the dissimilar material structural member 180 of this configuration example, the aluminum material 11 and the steel material 13 are arranged with a gap in the height direction, and this gap is filled with the aluminum alloy casting material. The plurality of through holes 19A, 19B, 21A, 21B are also filled with an aluminum alloy cast material. Thereby, the aluminum material 11 and the steel material 13 are joined with high strength through the cast-in part 17. And since the aluminum material 11 and the steel material 13 are integrally joined by one casting of casting, a manufacturing process can be simplified.

  The through holes 19, 19 A, 19 B, 21, 21 A, and 21 B are not limited to the round holes in the illustrated example, and may have any shape such as a square hole or a long hole. In addition to the cylindrical shape, the hole cross section may have a shape in which the area in the hole is increased or an inclined surface is provided, such as a taper shape or a shape in which a middle portion in the thickness direction protrudes inward. In this case, the bonding strength between the hole inner wall surface and the aluminum alloy cast material is further increased, and the rigidity of the dissimilar material structural member 180 can be further improved.

  Next, a configuration in which the dissimilar material structural member 180 having the above configuration is applied to a front subframe for an automobile will be described. FIG. 27 is a perspective view of a front subframe for an automobile.

  The front subframe 200 is one of vehicle frame structures, and a steel front member 51 disposed in front of the vehicle and an aluminum rear member 53 on which an engine or the like is mounted are formed by a pair of different-material structural members 180. It has a shape joined together.

  The front member 51 includes a front cross member 55 extending in the vehicle width direction (X direction) and a pair of support columns 57. The front cross member 55 and the pair of support columns 57 are made of steel. The pair of struts 57 are connected to both ends of the front cross member 55 in the vehicle width direction (X direction) and extend upward. The rear member 53 includes an aluminum alloy rear cross member 59 extending in the vehicle width direction (X direction).

  The pair of different material structural members 180 are joined between the front cross member 55 and the rear cross member 59. That is, one end of the pair of different-material structural members 180 is welded to the vehicle rear side at both ends in the vehicle width direction (X direction) of the front cross member 55, and the other end is in the vehicle width direction of the rear cross member 59. (X direction) It welds to the vehicle front side of both ends.

  As a result, the pair of dissimilar material structural members 180 are integrally connected to the front cross member 45 and the rear cross member 49, and are configured as one part of the front subframe 200.

  One end of the front cross member 55 and the dissimilar material structural member 180 are both made of steel, and the other end of the rear cross member 59 and the dissimilar material structural member 180 are both made of aluminum. Therefore, the front cross member 55 is welded to the steel material 13 made of the same material, and the rear cross member 59 is welded to the aluminum material 11 made of the same material. Therefore, since the dissimilar material structural member 180 is welded by the same material, a welding process is simplified and welding strength is also improved.

  According to the front subframe 200 configured as described above, the rear cross member 59 and the dissimilar structural member 180 on the rear cross member 59 side are made of aluminum, thereby reducing the weight and contributing to improving the fuel consumption of the vehicle. it can.

  As described above, the present invention is not limited to the above-described embodiments, and those skilled in the art can make changes and applications based on combinations of the configurations of the embodiments, descriptions in the specification, and well-known techniques. This is also the scope of the present invention, and is included in the scope of seeking protection.

DESCRIPTION OF SYMBOLS 11 Aluminum material 11a One end part 13 Steel material 13a One end part 15 Joint part 17 Cast-in part 19, 19A, 19B Through-hole 21,21A, 21B Through-hole 23 Protrusion 25 Spacer 100,110,120,130,140,150,160, 170,180 Different material structural members

Claims (6)

A dissimilar material structural member comprising an aluminum material made of aluminum or an aluminum alloy, a steel material, and a joint part for joining the aluminum material and the steel material,
The said joint part has a cast-in part where the said aluminum material and the said steel material are integrally cast with the aluminum alloy molten metal, and are fixed, The different-materials structural member characterized by the above-mentioned.   The dissimilar material structure member according to claim 1, wherein the aluminum material is an aluminum alloy wrought material.   3. The dissimilar material structure member according to claim 1, wherein a through-hole through which the molten aluminum alloy flows is formed in at least one of the aluminum material and the steel material. The aluminum material and the steel material are arranged to overlap,
The through hole is formed in both the aluminum material and the steel material,
The dissimilar material structural member according to claim 3, wherein the hole positions of the through holes of the aluminum material and the steel material coincide with each other in the overlapping direction.   5. The dissimilar material structural member according to claim 1, wherein the aluminum material and the steel material are disposed with a gap between the aluminum material and the steel material.   The dissimilar material structural member according to claim 5, wherein a spacer that forms the gap is provided between the aluminum material and the steel material.

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