JP2013022622A - Aluminum alloy member for different material joining, different material joining member, and different material joining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform different material joining of a steel material and an aluminum alloy material by spot welding using steel-made pierce metal even for an aluminum alloy extruded hollow shape material in a three-dimensional hollow shape.SOLUTION: An aluminum alloy member 1 for different material joining comprises a 7000 series aluminum alloy extruded hollow shape material 6 provided with an opening 7 for work beforehand, the steel-made pierce metal 20 is caulked beforehand, and when performing different material joining with a steel-made member, the steel-made pierce metal 20 and the steel-made member are joined by steel-steel spot welding.

Description

  The present invention relates to an aluminum alloy member for joining different materials to a steel member, a different material joining member obtained by joining the aluminum alloy member to a steel member, or a method for joining different materials to a steel member of the aluminum alloy member.

  As a door beam material (door reinforcing material) for automobiles, an aluminum alloy extruded shape is used instead of the conventional steel in order to absorb excellent impact energy and reduce the weight.

  Such an aluminum alloy door beam material includes a pair (two) of inner and outer flanges arranged at intervals in parallel to each other, and a pair (two) arranged at intervals to connect them together. And an aluminum alloy extruded hollow member having a substantially rectangular cross section.

  Such door beam material is attached to a steel door inner panel, for example, as described in Patent Document 1, steel brackets for attachment are fixed in advance at both ends thereof, in the assembly process, This bracket part is fixed to the inner panel (inside the door) with bolts and nuts.

  However, this bracket-type door beam requires a large number of parts and requires processing of the bracket, which increases the number of manufacturing processes. These increase the cost of door beams made of extruded aluminum alloy hollow shapes, and are adopted for automobiles. It is a factor that obstructs.

  To fix this door beam inside the door, place the door beam between the outer panel and the inner panel of the door, place a nut in the hole of the bracket, tighten it with bolts from the inner panel side, and tighten the bracket part to the inner part. At this time, it is necessary to support the nut between the outer panel and the inner panel with a tool and tighten the bolt in that state. Therefore, the workability of the door beam assembly process is poor.

  On the other hand, for example, in Patent Document 2, pilot holes are made at both ends of the flange portion of the door beam material, and in order to increase the number of threads, burring is performed on the holes, and screw holes are drilled in the hole wall. It is described that the door beam material is directly clamped and fixed inside the door with bolts. Since this method is bracketless (no bracket is used), it is advantageous in terms of cost, and it is not necessary to support the nut with a tool in the assembly process, so that workability is improved.

  However, it is difficult to form a hole wall that can actually increase the number of threads by burring, especially when high-strength materials are used, and burring workability is poor. In addition, when using high-strength JIS7000 series aluminum alloys as door beam materials There is a possibility that the stress corrosion cracking resistance due to the residual stress applied during the burring process becomes a problem. Further, the accuracy of burring processing varies, and it is difficult to obtain a stable screw strength. In addition, instead of performing burring, it is possible to increase the number of threads by thickening only the central part where the screw hole of the flange part is processed, but the thick part over the entire length of the extruded material Since it is formed, it goes against weight reduction.

  Therefore, as Patent Document 3, there is no problem in terms of workability, weight reduction and screw strength in the assembly process on the premise of bracket-less that is advantageous in terms of cost with respect to automobile door beams, and JIS 7000 series aluminum alloys are also applicable. Inventions aimed at obtaining possible door beams have been proposed.

  The present invention relates to a bracketless door beam that is fixed to the inside of a door of an automobile with a bolt, in which a hole into which a fastening bolt can be loosely fitted is formed at an end of a door beam base body, and a nut into which the fastening bolt is screwed. The member is attached so that the screw hole is located inside the hole.

  That is, the base of the door beam is the above-described aluminum alloy hollow extruded shape. Then, both ends of the shape member (base) are cut obliquely from the outer flange (outer flange) to the inner flange (inner flange) to form an opening to the outside. A through hole (baka hole) is vertically formed in the center of the end of the inner flange at the cut portion, and a nut member is attached in advance to the vehicle outer side immediately above the through hole. And the screw hole of this nut member is located inside the said through hole, and the volt | bolt screwed together in this screw hole is loosely fitted in the said through hole.

  When this door beam is attached to the inner panel of an automobile door, the door beam is arranged at a predetermined position between the inner panel and the outer panel, and the bolt tip is inserted through the bolt hole formed in the inner panel from the back side of the inner panel (inside the vehicle). Then, the door beam is fastened and fixed to the inner panel by screwing into the screw hole of the nut member through the through hole of the base. At this time, as specific fixing means, for example, welding, caulking, adhesion using an adhesive or the like, fitting, or a combination thereof can be considered. The material of the nut member may be either iron or aluminum alloy, and as a countermeasure against electrolytic corrosion, the bolt and nut member are subjected to chemical conversion treatment such as dacrozide treatment, chromate treatment, electroplating treatment, painting, etc., and a door beam is attached. It is desirable to perform hot-dip Zn plating on the inner panel.

  On the other hand, unless all parts of the vehicle body are made of an aluminum alloy material, in a normal automobile body, the newly applied aluminum alloy material is combined with a steel material (steel member) such as a steel plate or mold steel that is originally used in general. Need to be used. For this reason, an aluminum alloy member such as a door beam inevitably needs to be joined with a steel material and an aluminum-iron dissimilar material.

  As such a rivet for joining different materials between a steel material and an aluminum alloy material, a steel pierced metal has been proposed in Patent Document 4, for example. This steel pierced metal is driven into the aluminum alloy material side by a press device or the like, penetrates (inserts) the aluminum alloy material, and penetrates the shaft portion that discharges the aluminum alloy material for this through hole to the outside. And a wide head that remains on the surface side of the aluminum alloy material.

  Thereafter, in the spot welding apparatus, the other steel material to be joined is superimposed on the surface of the aluminum alloy material on the shaft tip end side of the rivet, and the shaft tip is brought into contact with the other steel material. A steel pierce metal (steel rivet) is sandwiched between a pair of electrodes and the electrode is energized while pressing the electrode toward the steel pierce metal and the steel material. Metal and steel can be joined by spot welding.

  Usually, when welding a dissimilar material between a steel material and an aluminum alloy material using fusion welding such as spot welding, a brittle Fe-Al intermetallic compound is generated at the joint interface between the aluminum alloy material and the steel material, It is difficult to perform welding joint with high joint strength. On the other hand, in spot welding using this steel pierced metal, the same kind of steel-steel is joined. For this reason, the brittle Fe-Al intermetallic compound which generate | occur | produces in the interface of an aluminum alloy material and steel materials at the time of dissimilar material welding joining of an aluminum alloy and steel is not produced | generated. Therefore, there is a feature that it is possible to perform dissimilar material joining between a steel material and an aluminum alloy material using spot welding.

Japanese Patent No. 2991843 Japanese Utility Model Publication No. 6-42344 JP 2001-301462 A JP 2010-207898 A

  However, even in the above-mentioned Patent Document 3, when the door beam is mounted, the bolt tip is inserted through the bolt hole formed in the inner panel from the back side (the vehicle inner side) of the inner panel, and the screw hole of the nut member is passed through the through hole of the door beam base. As many screws as the number of nuts provided on the door beam side are required to screw and fix the door beam to the inner panel. In other words, as long as these normal bolts and nuts are used for mechanical joining and fastening methods, the weight increases due to the increase in the number of parts, the cost increases, or the joint strength decreases due to space limitations (such as spacing) of the mounting nuts. Such problems are difficult to avoid.

  Furthermore, in the said patent document 3, there also exists a problem of the adhesion method to the inner flange of nut member itself attached beforehand. In Patent Document 3, this bonding method is not specifically described. However, as long as the nut member is temporarily fastened with an adhesive, it can be detached by an external force during the operation of fastening the door beam to the inner panel. There is sex. On the other hand, in order to firmly join the nut member by welding or the like, the labor and cost increase due to this welding cannot be ignored.

  Moreover, in the said patent document 4, it is only the example of joining of a planar aluminum alloy plate and a steel plate that becomes a joining object of steel piercing metal. That is, even if it sees the Example, steel pierce | metal piercing metal is driven into a 6000 series aluminum alloy plate (plate | board thickness 1.2mm), and it caulks to this aluminum alloy plate, Furthermore, steel pierce | metal piercing metal is made into steel plate SPCC ( Only an example of spot welding to a plate thickness of 1.0 mm is shown. For this reason, although the said patent document 4 is disclosing the example of dissimilar material joining using steel pierced metal, it is applicable only to the example of joining a planar aluminum alloy plate and a steel plate.

  An aluminum alloy extruded hollow member such as a door beam, which is a subject of the present invention, has a three-dimensional hollow shape having a closed cross section, as is well known, unlike a flat plate shape. For this reason, there is no planar plate-like part (space) which can pierce steel piercing metal. Moreover, even if steel pierced metal is driven in, there is no room or space for contacting an electrode for spot welding to the steel pierced metal. Therefore, Patent Document 4 cannot be applied to a case where an aluminum alloy extruded hollow member having a three-dimensional cross-sectional shape such as an automobile door beam and a steel member, which is a subject of the present invention, is joined as it is.

 In view of such circumstances, the object of the present invention is to provide a three-dimensional cross-sectional shape (hollow shape) aluminum alloy member (extruded hollow shape material) by spot welding using the steel piercing metal, It is to enable dissimilar material joining between a steel material and an aluminum alloy material. That is, the present invention provides an aluminum alloy member for dissimilar material joining to a steel member, a dissimilar material joining member obtained by joining the steel member and the aluminum alloy member, and a dissimilar material joining method of the aluminum alloy member to the steel member. The purpose is to provide.

  The gist of the aluminum alloy member for dissimilar material joining of the present invention to achieve the above object is an aluminum alloy member for dissimilar material joining with a steel member, and a pair of flanges of an inner side and an outer side parallel to each other, and It consists of a 7000 series aluminum alloy extruded profile having a hollow portion formed by a pair of webs connected to each other in the longitudinal direction, and corresponds to the joint portion of the extruded profile with the steel member on the inner flange A work opening is provided in advance in the outer flange portion, and a steel pierce metal comprising a head portion and a shaft portion is joined to the steel member of the inner flange through the work opening. Is driven from the hollow portion side of the extruded profile, and has a shaft portion penetrating the inner flange and a head portion remaining on the hollow portion side of the inner flange, Is that is fastened previously crimped with the inner flange.

  Further, the gist of the dissimilar material joining member of the present invention for achieving the above object is a dissimilar material joining member obtained by joining a steel member and an aluminum alloy member, and the aluminum alloy member includes an inner side and an outer side parallel to each other. And a pair of webs that connect the two to each other, and a hollow portion formed in a longitudinal direction of the 7000 series aluminum alloy extruded shape, and the steel in the inner flange of the extruded shape A working opening is provided in advance in a portion of the outer flange corresponding to a joint portion with the steel member, and a head portion is connected to the joint portion of the inner flange with the steel member through the work opening. A steel pierce metal comprising a shaft portion is driven from the hollow portion side of the extruded profile, and the shaft portion penetrating the inner flange and the middle of the inner flange In the hollow portion of the extruded shape member from the opening for working when the dissimilar material is joined to the steel member. One spot electrode inserted into the steel pierce metal and brought into contact with the head of the steel pierced metal and the other spot electrode brought into contact with a corresponding portion of the steel member are energized, and the steel pierce pierced The metal is spot welded to the corresponding part of the steel member, and the aluminum alloy member is joined to the steel member only by this spot welding other than the adhesive used selectively.

  Furthermore, the gist of the dissimilar material joining method of the aluminum alloy member of the present invention for achieving the above object is a dissimilar material joining method of the aluminum alloy member to the steel member, wherein the aluminum alloy member is parallel to the inside and outside. And a pair of webs that connect them to each other, and a hollow portion formed in a longitudinal direction of the hollow portion, the inner flange of the extruded shape member. A working opening is provided in advance in a portion of the outer flange corresponding to a joint portion with the steel member, and through the work opening portion, a joint portion with the steel member of the inner flange is provided. A steel pierce metal comprising a head and a shaft is driven from the hollow portion side of the extruded profile, and the shaft and the inner furan that penetrate the inner flange. A head portion that remains on the hollow portion side, and is caulked and fastened in advance to the inner flange, and when the dissimilar material is joined to the steel member, the hollow portion of the extruded shape member is inserted from the working opening portion. The steel pierced metal is inserted into the steel pierced metal by passing through one spot electrode and the other spot electrode brought into contact with the corresponding part of the steel member. Spot welding is performed with a corresponding portion of the steel member, and the adhesive is selectively used, and the aluminum alloy member is joined to the steel member only by spot welding.

  According to the present invention, in the aluminum alloy member (aluminum alloy extruded profile), an opening for work opened to the outside is provided in advance in the outer flange portion corresponding to the caulking position of the steel pierce metal. .

This working opening serves as a working opening for driving steel pierce metal from the hollow side of the extruded profile into the joint portion of the inner flange with the steel member. Further, in the case of dissimilar material joining (spot welding) with the steel member, a spot electrode is inserted into the hollow portion of the extruded shape member from the work opening and is brought into contact with the head of the steel pierce metal. Acts as a working opening.
In other words, the working opening referred to in the present invention is an opening that can be used for both piercing metal driving work and spot welding work.

  As a result, even if it is an aluminum alloy extruded shape such as a door beam, which is a three-dimensional hollow shape having a closed cross section, such as an automobile door beam, the steel material and the aluminum alloy material are spot welded using the steel piercing metal. It is possible to perform the dissimilar material joining with.

  This spot welding is the joining of the same kind of steel-steel between the steel pierce metal and the steel member. For this reason, an Fe—Al intermetallic compound is not generated at the interface between the aluminum alloy member and the steel member. As a result of the excellent joint strength of spot welding as described above, other joining means such as mechanical joining and fusion welding are available in addition to adhesives that are used selectively or supplementally, including when not used at all. It is absolutely unnecessary. Therefore, basically, the aluminum alloy member can be joined to the steel member only by spot welding.

  Moreover, depending on the welding conditions, of course, depending on the welding conditions, it is possible to heat the joining portion of the inner flange, which has been pre-crimped with the steel piercing metal, so that the residual stress at this portion is reduced. is there. The residual stress introduced by pre-injecting and caulking the steel pierce metal is stress corrosion cracking at the joint portion of the inner flange, particularly depending on the 7000 series aluminum alloy composition and thickness conditions of the aluminum alloy member or the use environment. Promotes sexual anxiety. However, if the residual stress at the joint portion of the inner flange can be reduced, such anxiety about stress corrosion cracking characteristic peculiar to the 7000 series aluminum alloy can be eliminated, and the aluminum alloy member can be made thinner and lighter with the highest strength. It is possible to apply a 7000 series aluminum alloy that can be made into a metal.

It is a perspective view which shows one Embodiment of the aluminum alloy member for different material joining of this invention. It is a perspective view which shows other embodiment of the aluminum alloy member for different material joining of this invention. It is a longitudinal cross-sectional view which shows the steel piercing metal driving | running | working parts of FIG. It is a longitudinal cross-sectional view which shows the steel piercing metal driving | running | working parts of FIG. It is a longitudinal cross-sectional view which shows the aspect of implantation of the steel piercing metal of FIG. It is a longitudinal cross-sectional view which shows the aspect of implantation of the steel piercing metal of FIG. It is a longitudinal cross-sectional view which shows the resistance spot welding process in embodiment of the dissimilar material joining method of this invention. It is a longitudinal section showing the dissimilar material joined object joined by the dissimilar material joining method of the present invention. It is a cross-sectional view of an automobile door to which the aluminum alloy member of the present invention is applied as an automobile door beam.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, the example of the aluminum alloy member for different material joining of this invention is each shown using FIG.

Aluminum alloy member 1:
The aluminum alloy member 1 for dissimilar material bonding shown in FIGS. 1 and 2 is a JIS to AA 7000 series aluminum alloy extruded shape 6 having the same shape (closed cross-sectional shape, the same size and thickness). Become. Incidentally, the difference between the two is only the way of providing the working opening 7 and the steel piercing metal 20.

  1 and 2, an aluminum alloy member 1 for joining different materials to a steel member is made of a 7000 series aluminum alloy extruded profile 6 which is a material and has a uniform rectangular hollow closed cross-sectional shape in the longitudinal direction. . The aluminum alloy extruded profile 6 has a pair of flat (plate-like) flanges 2 and 3 on the inside and outside that are parallel to each other, and a pair of flat (plate-like) webs 4 and 5 that connect them to each other. doing. And the hollow part 8 which these paired flanges 2 and 3 and a pair of webs 4 and 5 comprise has as a uniform cross section over the longitudinal direction. Hereinafter, such an aluminum alloy extruded shape member 6 is also referred to as an aluminum alloy extruded hollow shape member 6.

  The inner side and the outer side of the flange are referred to as, for example, a flange that is disposed outside the vehicle body when applied as a door beam of an automobile, and is referred to as an outer flange 3, and a flange that is disposed inside the vehicle body is referred to as an inner flange 2. It is called for convenience. These flanges have flat (plate-like) projecting flanges 2a, 2b, 3a, 3b that project outward in the width direction of the flange (left-right direction).

  The left and right webs 4 and 5 that connect the flanges 2 and 3 in parallel with each other at an interval are arranged in parallel to each other, and together with the flanges 2 and 3 constitute the rectangular hollow closed cross-sectional shape. The webs 4 and 5 themselves do not have to be flat and flat as shown in FIGS. For example, in the longitudinal cross section, both the webs 4 and 5 are either outward from each other, inward from each other, or in the same direction so that the central portion and the like are deformed into a dogleg shape to easily absorb the collision energy. It may be bent in the shape of a dogleg or a bellows.

Material Aluminum alloy extrusion 6:
The closed cross-sectional shape and the size and thickness (plate thickness) of each part of the extruded aluminum alloy material 6 as described above are appropriately designed according to the use and required characteristics of the aluminum alloy member 1 as well as the presence or absence of the overhanging flange. Is done. Even within the same flange or web, the thickness (plate thickness) can be changed according to the part. And it is also an advantage that the material is made of an aluminum alloy extruded shape (extruded hollow shape) so that such selection can be freely made.

  For example, in the embodiment of FIGS. 1 and 2, a door beam of an automobile is intended as a specific application. For this reason, the flanges 2 and 3 are flat (plate-like) projecting toward the outside in the width direction of the flange (left and right direction) in order to improve impact energy absorption of the collision (side collision) as the door beam. The overhanging flanges 2a, 2b, 3a and 3b are provided. For the same purpose, the inner overhanging flanges 2a and 2b are wider than the outer flanges 3a and 3b. In order to absorb impact energy, the inner and outer flanges 2 and 3 and the overhanging flanges 2a, 2b, 3a, and 3b that face (confront) the collision energy direction at the time of a side collision have the same thickness. Is thicker than the webs 4 and 5 which are expected to be deformed.

  However, the thickness (plate thickness) t of the inner flange 2 is related to the length L of the steel piercing metal 20 (the thickness of the head 21 + the length of the shaft portion 22) L. In this respect, in order to obtain the necessary joint strength (joint strength) between the steel piercing metal 20 and the steel member 10 within the range of the normal spot welding conditions between steels, which will be described later, The length L is preferably 7 mm or less. Therefore, the thickness (plate thickness) t of the inner flange 2 of the aluminum alloy member 1 to which the steel piercing metal 20 is caulked is also naturally 7 mm or less, and considering the strength and rigidity as a reinforcing material, it is 1.0 mm or more. , Preferably within a range of 7 mm or less.

  In addition, the composition and tempering of the 7000 series aluminum are within the standards of JIS or AA or within the known composition range, and the strength and workability required for the use of the aluminum alloy member 1 or the corrosion resistance. The alloy billet is appropriately designed according to characteristics such as hot extrudability (productivity, extrusion efficiency) to the hollow shape member 6. 7000 series aluminum alloy composition composition is Al-Zn-Mg-Cu composition such as 7075 and Al-Zn-Mg composition not containing Cu such as 7N01. Heat treatment: T1 to T6 are appropriately designed.

  The aluminum alloy extruded hollow member 6 itself is partially covered with an insulating sealer layer and / or an adhesive layer (resin layer) for preventing electric corrosion between a steel piercing metal 20 and an aluminum alloy member 1 described later. Other than (application), a known anticorrosion coating or coating film is unnecessary. However, since the steel member and the dissimilar material joined body are configured as an automobile member or the like, the necessary coating on the steel material side may be applied in the same manner as the steel material after joining with the steel material.

Working opening 7:
The work opening portion 7 in FIG. 1 is an opening portion that performs both or both of the piercing metal driving operation and the spot welding operation together with the work opening portion 7 in FIG. 2. The working opening 7 in FIG. 1 is obtained by cutting the outer flange 3 and the webs 4 and 5 obliquely downward from the outer flange 3 side toward the inner flange 2 side, for example, by cutting. As a result, the joint portion 2c of the inner flange 2 to be described later with the steel member 10 or the upper part of the two piercing metal 20 staking (caulking) positions (2c) is directed to the outside (upward), and the entire surface Open.

  2 is provided with two circular openings (through holes) 7 in the outer flange 3 by drilling or the like, and a joint portion 2c of the inner flange 2 with a steel member 10 described later. Alternatively, the upper portion of the piercing (clamping) position (2c) of the two steel piercing metals 20 is opened toward the outside (upward).

  As described above, the working opening 7 provided on the outer flange 3 and opened to the outside is selected in shape, size and number according to the working conditions of both the piercing metal driving work and the spot welding work. Provide. That is, depending on the number of the joining portion 2c of the inner flange 2 with the steel member 10 or the position (2c) at which the steel piercing metal 20 is driven (2c), the size (diameter) of the steel piercing metal 20, etc. In addition, the size, shape, and number are designed according to the size (diameter) of the spot electrode 33 (FIG. 7 described later) to be inserted. More specifically, these steel pierced metal heads 21 and spot electrodes 33 are inserted into the hollow portion 8 from the outside, and the pierced metal heads 21 made of steel and The size exceeds the diameter of the spot electrode 33. However, the upper limit of the size and the number is naturally determined from the viewpoint of not deteriorating the characteristics such as strength and rigidity that are originally required for the reinforcing material such as the door beam of the aluminum alloy member 1.

Steel piercing metal 20:
As shown in FIGS. 1 and 2, a steel pierce metal 20 is driven from the hollow 8 side of the extruded hollow member 6 into a joint portion 2 c of the inner flange 2 of the aluminum alloy member 1 with a steel member 10 described later. . Here, 21 is a steel pierce metal head, which is shown in FIGS. 3 and 4 and is an upper part of the shaft portion 22 penetrating the inner flange 2 and remains on the surface of the inner flange 2 (hollow 8 side). It is the head of pierced metal.

  3 and 4 show a longitudinal section of a portion where the steel pierce metal 20 is driven in the aluminum alloy member 1 for joining different materials shown in FIGS. The difference between FIG. 3 and FIG. 4 is only the cross-sectional shape of the steel piercing metal 20 composed of the head and the shaft. 3 and 4 are common to both types of the aluminum alloy member 1 for joining different materials shown in FIGS.

  3 and 4, a steel pierced earring is formed through a work opening 7 (illustrated in the type of FIG. 2) of the outer flange 3 in a joint portion 2 c of the inner flange 2 of the aluminum alloy member 1 with a steel member 10 described later. A metal 20 is driven from the hollow 8 side. And it has the shaft part 22 which penetrated the inner side flange 2, and the head 21 which remains on the surface (hollow 8 side) of the inner side flange 2 by the caulking method mentioned later, and is crimped by the inner side flange 2 beforehand, and is fastened. ing.

  A steel piercing metal 20 shown in FIGS. 3 and 4 includes a disc-shaped head 21 and a shaft 22 formed coaxially with the center of the head 21. Although the shaft portion 22 has the same diameter in the axial direction, the diameter (cross-sectional area) may be greatly widened from the proximal end on the head portion 21 side toward the distal end 23 side of the shaft portion 22.

  In FIGS. 3 and 4, in common, the central portion is shaped like a tip 23 of the shaft portion 22 so that it is raised (sharpened) from the peripheral portion. This is for the purpose of improving the spot weldability by contacting and energizing only with the tip 23 and for facilitating driving into the surface of the inner flange 2. Incidentally, the difference between FIGS. 3 and 4 is only the cross-sectional shape of the tip 23 of the steel piercing metal 20, and the tip 23 of FIG. 4 is sharpened more than the tip 23 of FIG. The tip 23 is gently curved from the peripheral edge 25 of the shaft portion toward the center tip 23, but the curvature and the shape of the curve are arbitrary.

  A groove 24 is formed on the surface of the head 21 of the steel piercing metal 20 that overlaps the aluminum alloy member 1 (inner flange 2) so as to surround the shaft portion 22. In this groove 24, a portion of the aluminum alloy (inner flange 2) that was pressed during the piercing and caulking of the steel piercing metal 20 described later in FIGS. 5 and 6 was formed around the shaft portion of the head 21. It is a groove for plastically flowing into and entering the groove 35.

Placing and caulking steel piercing metal 20:
Next, a method for driving, caulking, and fastening the steel pierce metal 20 will be described with reference to FIGS. 5 and 6 are cross-sectional views showing a process for driving the steel piercing metal 20. These FIGS. 5 and 6 are common to both types of the aluminum alloy member 1 for joining different materials shown in FIGS.

  First, as shown in FIG. 5, the inner flange 2 of the aluminum alloy member 1 is placed on a cylindrical support base 32. Then, the steel pierce metal 20 sandwiches the inner flange 2 from the hollow 8 side through the working opening 7 (illustrated in the type of FIG. 2) of the outer flange 3, and the later-described steel member 10 of the inner flange 2 is inserted. It arrange | positions on the junction site | part 2c. The steel piercing metal 20 is driven toward the aluminum alloy member 1 (inner flange 2) by the punch 31 inserted from the working opening 7 of the outer flange 3 described above.

  Specifically, as shown in FIG. 6, when the punch 31 is lowered as indicated by an arrow and the steel piercing metal 20 is pushed into the aluminum alloy member 1 (inner flange 2), the shaft portion of the steel piercing metal 20. The aluminum alloy material 2d portion corresponding to 21 is punched by the shaft portion 21 so that the punched portion 2d falls into the cylinder of the support base 32.

  Here, the steel piercing metal 20 is pressed toward the inner flange 2 by the punch 31. For this reason, the axial part 22 penetrates the inner side flange 2, and the front end surface 23 is exposed to the lower surface side (steel member 10 side mentioned later) of the inner side flange 2. FIG. Further, in the groove 24 around the shaft portion 22 on the lower surface of the head portion 21, the aluminum alloy material (of the inner flange 2) sandwiched between the head portion 21 and the support base 32 is plastically flowed, invade. As a result, the steel piercing metal 20 is caulked to the inner flange 2 of the aluminum alloy member 1 and is firmly fastened (joined and fixed) prior to spot welding.

  Accordingly, the groove (recess) 24 is an annular groove (recess) along the periphery of the shaft portion 22 on the lower surface of the head portion 21 and the aluminum alloy material is intruded by plastic flow so that the steel pierce metal 20 is placed inside. It becomes a key for caulking and fastening to the flange 2. The groove 24 does not need to be a continuous annular groove, and may be an intermittent annular groove with an interval, but if the depth or width of the groove is too small or the groove itself does not exist, There is no or insufficient caulking mechanism, and the caulking strength is insufficient.

  By such caulking action of the aluminum alloy member 1 by the steel piercing metal 20, the aluminum alloy member 1 is formed on the spot welded portion of the steel-steel same material between the steel piercing metal 20 and the steel member 10. Further, a joining force (mechanical joining force) due to caulking with the steel pierce metal 20 is further applied. For this reason, the joint strength as a dissimilar material joined body can be increased to, for example, 5 kN or more by a synergistic effect of both joints of spot welding and caulking.

  Such steel piercing metal 20 can be driven using a general-purpose press. At this time, by selecting the optimum press forming conditions, the steel pierce metal 20 is driven into (injected into or embedded in) the aluminum alloy member 1 in accordance with the shape and thickness (diameter) of the shaft portion 22 of the steel pierce metal 20. ) And the occurrence of cracking on the aluminum alloy member 1 (inner flange 2) side can be prevented.

  Here, the shape, cross-sectional shape, size, or strength (hardness) related to the steel composition and heat treatment of the head 21, the shaft 22, the tip 23, and the groove 24 of the steel piercing metal 20 is driven and caulked. It is suitably designed according to the hardness and thickness of the extruded aluminum alloy material 6 to be obtained, or the required caulking strength before spot welding or the dissimilar material joining strength after spot welding. For example, the steel piercing metal 20 itself is normally manufactured (processed) from a steel wire, but the material steel wire may be high strength steel (high tensile) or ordinary steel.

  More specifically, the length (the thickness of the head 21 + the length of the shaft portion 22) L of the steel piercing metal 20 is the thickness (plate thickness) of the inner flange 2 of the aluminum alloy member 1 as described above. According to t, it is preferable to set it as the range of 1.0 mm or more and 7 mm or less. Moreover, it is preferable to select the diameter of the head 21 from the range of 4-10 mm larger than the diameter mentioned later of the spot welding electrode 33 which contacts and supplies this with the point which obtains joining strength and electroconductivity. Furthermore, the diameter of the shaft 22 is preferably selected from a range of 3 to 9 mm in diameter from the energization at the time of spot welding and the driveability according to the thickness (plate thickness) t of the inner flange 2. This is because the thickness (plate thickness) t of the inner flange 2 of the aluminum alloy member 1 to be joined is 1.0 mm or more and 6 mm or less, and the thickness t of the steel member 10 is 0.3 to 5 described later. It is assumed that the required joint strength is obtained by spot welding the steel piercing metal 20 to the steel member 10 within a range of 0.0 mm.

  Here, in order to prevent electrolytic corrosion between the steel piercing metal 20 and the aluminum alloy member 1, it is preferable not to directly contact them. For this purpose, an insulating sealer layer and / or an adhesive layer (resin layer) 30 is coated (applied) on the lower surface of the disc-shaped head portion 21 and the surface of the shaft portion 22 of the steel piercing metal 20. Thus, it is preferable that the steel piercing metal 20 is caulked (contacted and overlapped) with the inner flange 2 of the aluminum alloy member 1 through the insulating layer 30. Such an insulating sealer layer and / or adhesive layer (resin layer) 30 selects a commercially available (known) resin and an optimum coating amount (coating thickness) determined by each resin.

Production of dissimilar material joints by spot welding:
A method of joining different materials between the aluminum alloy member 1 and the steel member 10 will be described with reference to FIGS.

  First, as shown in FIG. 7, when different materials are joined between the aluminum alloy member 1 (inner flange 2) and the steel member 10, first, the aluminum alloy member 1 (inner flange 2) and the steel member 10 are joined. Overlapping. Then, the spot electrode 33 is inserted into the hollow 8 through the working opening 7 (illustrated in the type of FIG. 2) of the outer flange 3 and is brought into contact with the head 21 of the steel piercing metal 20. Then, the spot electrode 33 and the other spot electrode 34 brought into contact with the corresponding portion 10a on the steel member 10 side corresponding to the joining portion 2c of the inner flange 2 are energized and spot-welded.

  Thus, as shown in FIG. 8, the steel pierce metal 20 at the position of the joint part 2 c of the inner flange 2 of the aluminum alloy member 1 is spot-welded 35 to the corresponding part 10 a of the steel member 10. In addition, although the above aspect was shown about the type of the aluminum alloy member 1 of the said FIG. 2, even if the opening part for work like the said FIG. 1 is a notch type, it becomes the completely same joining procedure.

  Such spot welding is performed by resistance spot welding. The spot electrodes 33 and 34 are driven so as to approach each other, and the steel piercing metal 20 (the inner flange 2 of the aluminum alloy member 1) and the steel member 10 A clamping force is applied between the two. Then, resistance spot welding is performed by applying a pulse current between the spot electrodes 33 and 34. At this time, since the shaft portion 22 penetrates the steel pierce metal 20, the tip 23 of the shaft portion 22 and the steel member 10 come into contact with each other.

  At this time, when the tip 23 is formed in a shape in which the central portion is raised (pointed) as compared with the peripheral portion as shown in FIGS. Can touch. For this reason, since the energizing current flows only on the tip surface 23, the steel pierce metal 20 and the steel member 10 are joined in a region centered on the center tip surface 23 or the axial center of the shaft portion 22. Can do.

  Further, when the axis of each of the steel pierce metal 20 and the spot electrodes 33 and 34 coincides, the energized current flows through these axes. For this reason, during spot welding, the aluminum alloy material of the inner flange 2 around the shaft portion 22 of the steel pierce metal 20 is not excessively heated, and the aluminum alloy material is not softened or melted. The obtained joint strength does not decrease. This is the same even when the tip 23 of the steel piercing metal 20 is pointed or flat as shown in FIGS.

Spot welding conditions:
Since the present invention is not the steel-aluminum dissimilar material joining but the same kind of joining between the steels, it is an advantage that the milder spot welding conditions generally used between the steels can be applied as they are. In other words, the present invention has a great advantage in that, although it is an aluminum-iron dissimilar material joining, the conditions commonly used for spot joining of the same kind of normal steel-steel materials can be applied.

  As a preferable condition for each welding spot of such spot welding, it is preferable that the applied pressure between the electrodes is in the range of 1.0 to 5.0 kN. Further, the current between the electrodes may be in the range of 5 to 13 kA (preferably 7 to 8 kA), and the current may be applied for a time of 200 × t (msec) or less in relation to the thickness t (mm) of the steel plates to be joined. preferable.

This is because the thickness t ₂ of the inner flange 2 of the aluminum alloy member 1 to the length of the steel piercing metal 20 (the thickness of the head 21 + the length of the shaft portion 22) L is 5 mm or less, and is made of steel. When the plate thickness of the member 10 is 3 mm or less, and a “dome-shaped” electrode (diameter 10 to 20 mm, radius of curvature of the tip surface is 20 mm or more) made of an ordinary chromium copper alloy tip R is used as the spot electrode Is the optimal range.

Steel - For dissimilar metals joint of aluminum, for example, for the pressure applied during spot welding, as a guide for obtaining the required bonding strength, applying a relatively high pressure of ^{_{2 × t 2 0.5 kN~4 × t}} 2 0.5 kN There is a need to. However, as described above, in the present invention, welding is possible with a lower pressing force. Also, the current during spot welding must be a relatively high current of 10 × t ₂ ^{0.5 to} 20 × t ₂ ^0.5 kA in relation to the thickness t ₂ of the inner flange 2 of the aluminum alloy member 1. It is. However, as described above, in the present invention, welding is possible even at a lower current.

Residual stress reduction:
On the other hand, at the time of this spot welding, it is preferable that the joining part 2c of the inner flange 2 that has crimped the steel pierce metal 20 is heated so that the residual stress at this part is reduced. When the steel piercing metal 20 is driven or caulked as shown in FIGS. 3 and 4, the aluminum alloy material around the shaft portion 22 of the steel piercing metal 20 at the joint portion 2c of the inner flange 2 is inevitably used. Residual stress is applied.

  Incidentally, as described above, residual stress is applied even in burring processing for making pilot holes at both ends of the flange portion of the door beam material and increasing the number of threads as in Patent Document 2. Such residual stress is hardly a problem in other aluminum alloys such as 6000 series, but 7000 series aluminum alloy that contains Zn and the like at a high concentration and ensures high strength is highly susceptible to stress corrosion cracking. . For this reason, it cannot be denied that such residual stress may lead to a problem of stress corrosion cracking in a usage mode such as a door beam material.

  For this reason, when such residual stress becomes a problem, the steel pierce metal 20 is caulked during the spot welding, and the residual stress at this portion is reduced at the joint portion 2c of the inner flange 2 that is fastened. To heat. Such heating is performed by welding conditions such as the shape (size), thickness, and diameter of the steel pierce metal 20, the inner flange 2 of the aluminum alloy member 1, the steel member 10, and the like, as well as the welding current and energization time. Design and select the spot welding conditions. However, the design and selection are made so as not to lower the weld joint strength (joint strength) or to soften or melt the aluminum alloy material. As a measure of this heating, the temperature of the aluminum alloy member 1 (inner flange 2) within 10 mm around the steel pierce metal head 21 is 100 to 500 ° C. as the instantaneous maximum temperature during spot welding. It is preferable to be heated to a degree.

Example of dissimilar material joint:
FIG. 9 shows an example in which the dissimilar material joined body shown in FIG. 8 is applied to an automobile door. That is, an example of an automobile door in which the steel piercing metal 20 of the inner flange 2 of the aluminum alloy member 1 is spot welded 35 to the steel member 10 is shown. In FIG. 9, 12 is a steel door outer panel, 1 is a door beam (door reinforcing material) made of an aluminum alloy material, and 10 is a door inner panel of a steel member 10 to be joined to the door beam. In addition, although this aspect was shown about the type of the aluminum alloy member 1 of the said FIG. 2, even if the opening part for work like the said FIG. 1 is a notch type, it becomes the completely same joining procedure.

  When the door beam 1 is attached to the inner panel 10 of the automobile door, the door beam 1 is disposed at a predetermined position (attachment position 10a) of the inner panel 10 as shown in FIG. Then, the steel pierce metal 20 of the inner flange 2 of the aluminum alloy member 1 is spot-welded to the steel member 10 in the manner described above with reference to FIG. At this time, the outer panel 12 may be joined to the inner panel 10 to which the door beam 1 is previously attached. The outer panel 12 is joined to the inner panel 10 first, and the door beam 1 is connected to the inner panel 10 from a work port provided in the outer panel 12. You may attach to.

  By the way, usually (conventionally), the bolt 9 is inserted through the bolt hole 13 formed in the inner panel 10 from the back side (the vehicle inner side) of the inner panel 10, and through the bolt hole formed in the inner flange 2 of the door beam 1. A complicated operation of screwing and fixing the door beam 1 with the nut member is required. Even when the bracket is attached to the door beam 1, the mounting procedure using the bolts and nuts of the bracket is the same, and complicated work is required.

  As the inner panel 10 or the outer panel 1 as the steel member 10, a molded product obtained by press-molding a high strength steel (high-tensile steel) or a thin steel plate of ordinary steel is used as in a normal automobile panel or door panel. The thickness t of these panels is also in the normal range of 0.3 to 5.0 mm. As usual, metal plating film such as zinc or zinc alloy, organic resin film such as paint, lubricant, and / or lubricating oil. In general, a known film applied to the steel sheet can be formed. These may be used alone or in combination with a plurality of coatings. Moreover, you may coat | cover either a single layer or a multilayer.

  According to the present invention, even if it is an aluminum alloy extruded hollow member having a three-dimensional hollow shape having a closed cross section such as a door beam of an automobile, the steel material and the aluminum alloy material are spot-welded by using the steel piercing metal. Aluminum alloy member for dissimilar material joining with steel member, dissimilar material joining member joining steel member and this aluminum alloy member, dissimilar material with steel member of this aluminum alloy member A bonding method can be provided. Therefore, it is suitable when attaching the reinforcing material which consists of the said aluminum alloy extrusion hollow shape material to the steel panel structure body of a motor vehicle.

1: Aluminum alloy member for joining different materials, 2: Inner flange, 3: Outer flange, 4, 5: Web, 6: Aluminum alloy extruded hollow member, 7: Work opening, 8: Hollow (part), 10: Steel member, 20: Steel pierced metal, 21: Steel pierced metal head, 22: Steel pierced metal shaft, 23: Steel pierced metal tip, 24: Steel pierced metal groove (part), 25: Steel pierced metal corner, 30: Sealer, 31: Punch, 32: Support base (jig), 33, 34: Spot electrode,

Claims (11)

An aluminum alloy member for joining dissimilar materials to a steel member, and having a hollow portion in the longitudinal direction formed by a pair of flanges of an inner side and an outer side parallel to each other and a pair of webs connecting them to each other. 7000 series aluminum alloy extruded profile, and a work opening is provided in advance in a portion of the outer flange corresponding to a joint portion with the steel member in the inner flange of the extruded profile. A steel pierce metal consisting of a head portion and a shaft portion is driven from the hollow portion side of the extruded shape member into the joint portion of the inner flange with the steel member through the opening, and penetrates the inner flange. And a head portion remaining on the hollow portion side of the inner flange, and is caulked and fastened to the inner flange in advance. Aluminum alloy member.   The aluminum alloy member for joining dissimilar materials according to claim 1, wherein the steel pierced metal is caulked in advance on the inner flange via an insulating sealer layer and / or an adhesive layer.   The aluminum alloy member for joining different materials according to claim 1 or 2, wherein the aluminum alloy member is an automobile door beam, and the steel member is a door inner panel. A dissimilar material joining member obtained by joining a steel member and an aluminum alloy member, the aluminum alloy member comprising a pair of flanges of an inner side and an outer side which are parallel to each other, and a pair of webs which connect them to each other A working opening in a portion of the outer flange corresponding to a joint portion with the steel member in the inner flange of the extruded shape member. Is provided in advance, and a steel pierce metal comprising a head portion and a shaft portion is driven from the hollow portion side of the extruded shape member into the joint portion of the inner flange with the steel member through the working opening. And having a shaft portion that penetrates the inner flange and a head portion that remains on the hollow portion side of the inner flange, and is caulked in advance on the inner flange. One spot that is fastened and inserted into the hollow portion of the extruded shape member from the working opening and brought into contact with the head of the steel pierce metal during the dissimilar material joining with the steel member The electrode and the other spot electrode brought into contact with the corresponding part of the steel member are energized, and the steel pierce metal is spot-welded with the corresponding part of the steel member and selectively used. The aluminum alloy member is joined to the steel member only by this spot welding in addition to the adhesive.   The dissimilar material joining member according to claim 4, wherein a portion for joining the inner flange, in which the steel pierced metal is caulked in advance, is heated by the spot welding so that residual stress at the portion is reduced.   The dissimilar material joining member according to claim 4 or 5, wherein the steel pierced metal is caulked in advance on the inner flange via an insulating sealer layer and / or an adhesive layer.   The dissimilar material joining member according to any one of claims 4 to 6, wherein the aluminum alloy member is an automobile door beam, and the steel member is a door inner panel. A method of joining dissimilar materials of an aluminum alloy member to a steel member, wherein the aluminum alloy member has a hollow portion formed by a pair of inner and outer flanges parallel to each other and a pair of webs connecting them together. It is made of a 7000 series aluminum alloy extruded shape having a longitudinal direction, and a working opening is provided at a portion of the outer flange corresponding to a joint portion with the steel member in the inner flange of the extruded shape. A steel pierce metal consisting of a head portion and a shaft portion is driven from the hollow portion side of the extruded shape member into the joint portion with the steel member of the inner flange through the working opening. A shaft portion penetrating the inner flange and a head portion remaining on the hollow portion side of the inner flange, and caulked and fastened to the inner flange in advance, Correspondence between the steel member and one spot electrode which is inserted into the hollow of the extruded shape member from the working opening and brought into contact with the head of the steel pierce metal when joining different materials to the member The other spot electrode brought into contact with the part to be energized is spot-welded to the corresponding part of the steel member by spot welding the steel pierce metal. The aluminum alloy member is joined to the steel member by a method for joining different materials of an aluminum alloy member.   9. The dissimilar material joining method according to claim 8, wherein a part for joining the inner flange, in which the steel pierced metal is caulked in advance, is heated by the spot welding so that residual stress in the part is reduced.   The dissimilar material joining method according to claim 8 or 9, wherein the steel pierced metal is caulked to the inner flange in advance via an insulating sealer layer and / or an adhesive layer.   The dissimilar material joining method according to any one of claims 8 to 10, wherein the aluminum alloy member is an automobile door beam and the steel member is a door inner panel.

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