JP4755887B2 - Material joining method - Google Patents

Description

  The present invention relates to a method for joining materials.

  In recent years, in the automobile industry, lightweight materials such as aluminum have been actively adopted from the viewpoint of reducing the weight of vehicles with the aim of improving fuel efficiency, etc., which makes it difficult to weld different materials such as aluminum and iron. The importance of joining technology has increased, but conventionally, for joining different types of materials that are difficult to weld, means such as fastening with bolts, joining with mechanical clinch, and adhesion with adhesives have been used. ing.

Incidentally, as prior art document information related to the material joining method of the present invention described later, there is the following Patent Document 1 and the like.
JP 2004-136365 A

  However, for example, when fastening with bolts is adopted, bolts and nuts protrude as projections on the front and back surfaces of the materials to be joined, and therefore the space occupied by these projections must be ensured by design. There are restrictions, and there are also concerns about loosening and falling off when tightening with bolts, and when joining by mechanical clinch is adopted, joining of thin plates is the center, and heat is not applied to the material. Since joining is performed only by pressure, there is a problem that quality defects such as cracks and deformation are likely to occur.

  Furthermore, when adhesive bonding is used, in addition to the problem of poor workability and working environment, there is a problem of poor recyclability because it is difficult to separate the adhesive from the material during recycling. .

  The present invention has been made in view of the above-mentioned circumstances, and there is no need to worry about protrusions, loosening and dropping off of projections, which can be a design constraint, and bonding is possible in a wide range from thin plates to thick plates. It is another object of the present invention to provide a method for joining materials that can avoid the occurrence of quality defects such as cracks and deformation, and can perform joining with excellent recyclability while maintaining good workability and work environment. And

According to the present invention, a first material in which a joint hole is previously drilled and a groove is formed in advance on the inner surface of the joint hole is sandwiched between the second material and the third material so as to cover the joint hole, A joining tool having a pin part that can be inserted into the joining hole is arranged in correspondence with the joining hole, and the pin part is pressed against the second material while rotating the joining tool, and the second tool is placed between the second material and the pin part. The second material is locally softened in the solid state by the frictional heat generated in the first and then enters the first material in the joint hole, and is fitted into the groove on the second material side that has entered the joint hole. the rewritable forming crest, the pin portion also pressing said third material was allowed to locally soften remain in a solid phase state by frictional heat to the third material, wherein the second material intruded into the junction hole After stirring the boundary part with the third material, the joining tool is pulled out, and the boundary part Method of bonding material, characterized by joining the first material to cure the second material and the third material in three-ply and those of the.

  Thus, in this way, the second material that has entered and hardened into the joint holes of the first material is subjected to friction stir welding (abbreviated as FSW) to the third material. The first material is firmly held between the two materials and the third material, and the first material, the second material, and the third material can be satisfactorily joined in a three-layered manner.

  At this time, the second material entering the first material joining hole is merely friction stir welded to the third material side, and projections such as bolts and nuts in the case of bolt fastening do not protrude. Therefore, there is no design restriction such as securing an occupied space of this kind of projection, and there is no worry of loosening or dropping off when bolt fastening is employed.

  In addition, the friction material is softened by applying frictional heat to the second material by the pin portion of the joining tool, and then the first material enters the joint hole, and the boundary portion between the second material and the third material enters the joint hole. However, the first material, the second material, and the third material are completely agitated without applying excessive pressure on the first material side that is softened and stirred while applying frictional heat. It is possible to cope with a relatively large plate thickness, and bonding will be realized in a wide range from thin plates to thick plates, and quality defects such as cracks and deformation will occur in advance. It will also be avoided.

  Furthermore, since the first material, the second material, and the third material are firmly joined without an inclusion such as an adhesive, workability and a work environment as in the case of using an adhesive are deteriorated. It is not necessary to invite them, and in addition, a joining with excellent recyclability that facilitates separation work during recycling is realized.

Also, previously forming the groove on the inner surface of the joining hole of the first material, wherein since so as to form a peak portion of the groove and the fitting to the second material side which intruded into the junction hole, By fitting the groove on the first material side and the peak on the second material side, the effect of retaining and preventing rotation is achieved, and the first material, the second material, and the third material are more firmly joined. Will be.

  In the present invention, if the plate thickness of the second material to be superimposed on the first material is too thin and there is a possibility that the second material to be inserted into the joining hole is insufficient, the first material on the second material side It is possible to compensate for the material shortage by partially increasing the thickness of the position corresponding to the joint hole.

  Furthermore, the material joining method of the present invention may be such that the first material is sandwiched between the second material and the third material with the bifurcated ends of the same material. Three-layer joining of the material and the third material is realized.

  Alternatively, the first material may be spot-formed with a bonding hole, and the bonding tool may be positioned at one point corresponding to the bonding hole to perform spot bonding. The joining hole may be formed in a slit shape, and continuous joining may be performed by moving the joining tool in the longitudinal direction of the joining hole.

  According to the above-described material joining method of the present invention, since there is no protrusion of a projection such as a bolt or a nut in the case of bolt fastening, design restrictions can be greatly eased, and in the case of bolt fastening. It is possible to eliminate worries such as loosening and falling off, and it is possible to join in a wide range from thin plates to thick plates and to avoid the occurrence of quality defects such as cracks and deformations. Various excellent effects can be achieved, such as bonding with excellent recyclability while maintaining good performance and working environment.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 4 show an example of an embodiment for carrying out the present invention. In this embodiment, the first material 1 made of iron is sandwiched between the second material 2 and the third material 3 made of aluminum, and three layers are stacked. The case of spot joining is illustrated.

  As shown in FIG. 1, the first material 1 has a joining hole 4 penetrating in the thickness direction in a spot shape, and a spiral groove portion 5 is formed on the inner peripheral surface of the joining hole 4 by screw machining. In addition, a backing member 6 is disposed on the lower surface side (the anti-second material 2 side) of the third material 3 so as to correspond to the position of the joining hole 4.

  Further, on the upper side of the second material 2, a cylindrical joining tool 8 having a pin portion 7 that can be inserted into the joining hole 4 of the first material 1 at the lower end is disposed concentrically with the joining hole 4. It is supported so as to be rotatable and movable up and down by a joining device (not shown).

  In joining the first material 1, the second material 2 and the third material 3 thus overlapped with the joining tool 8, the joining tool 8 is rotated from the state shown in FIG. 1 as shown in FIG. 2. The pin portion 7 is lowered and pressed against the second material 2, and the second material 2 is locally kept in a solid state by the frictional heat generated between the second material 2 and the pin portion 7 of the welding tool 8. Soften and enter the joining hole 4 of the first material 1.

  Further, as shown in FIG. 3, when the joining tool 8 is lowered to a position where the shoulder portion 9 contacts the surface of the second material 2, the second material 2 that has entered the joining hole 4 is joined to the joining hole by plastic flow and press-fitting. 4, and a spiral (thread-like) peak 5 ′ is formed on the second material 2 side by fitting with the spiral groove 5 of the joint hole 4. A mechanical engagement with the one material 1 side is made.

  In addition, when the pin portion 7 of the welding tool 8 is pressed against the surface of the third material 3 and the third material 3 is locally softened in a solid state by frictional heat, the second material 3 entered the bonding hole 4 is obtained. The boundary portion 10 between the two materials 2 and the third material 3 is agitated, and then, as shown in FIG. 4, the joining tool 8 is pulled upward, and the peak portion 5 ′ and the boundary portion 10 are pulled out. Is cured, the second material 2 that has entered and hardened into the joint hole 4 of the first material 1 is friction stir welded to the third material 3 (Friction Stir Welding: abbreviated as FSW). However, the peak portion 5 ′ formed between the first material 1 and the first material 1 side has an effect of preventing slipping and rotation.

  That is, according to the structure in which the first material 1 is firmly held between the second material 2 and the third material 3 as described above, the axial direction of the joint hole 4 (vertical direction in FIG. 4). The relative displacement of the first material 1, the second material 2, and the third material 3 toward the surface is fixed to obtain a retaining effect, and the relative displacement in the axial direction is fixed in this way. Prevents rotation around the axis with relative displacement in the same direction (the groove 5 of the joint hole 4 and the ridge 5 'on the second material 2 side are in a threaded state), making it impossible to rotate. The first material 1 is firmly held between the second material 2 and the third material 3, and the first material 1, the second material 2 and the third material 3 are stacked in three layers. Good bonding is realized.

  In fact, in the verification experiment by the present inventor, the first material 1 having a thickness of 5 mm is sandwiched between the steel plates SS400 as an intermediate plate, the second material 2 having a thickness of 5 mm and aluminum 6000 is stacked on the upper plate, and the aluminum 6000 system is stacked on the lower plate. It was confirmed that a tensile shear strength of about 12.26 kN can be obtained in the joining when the third material 3 having a thickness of 4 mm is stacked.

  In addition, although the case where the spiral groove part 5 was screw-processed on the internal peripheral surface of the joining hole 4 was illustrated here, this groove part 5 is not necessarily limited to forming in a spiral shape, for example, ring shape It is possible to obtain the effect of retaining and preventing rotation by a combination of the groove portion 5 and the spline-like groove portion 5 (a combination of the spiral groove portion 5 and the spline-like groove portion 5 is also possible).

  Further, in the present embodiment, the second material 2 entering the joining hole 4 of the first material 1 is merely friction stir welded to the third material 3, such as a bolt or nut in the case of bolt fastening. Since the protrusions do not overhang, there is no design restriction such as securing the space occupied by this kind of protrusions, and there are concerns about loosening and falling off when using bolt fastening. Also disappear.

  In addition, the second material 2 is softened by applying frictional heat to the second material 2 by the pin portion 7 of the joining tool 8, and then enters the joining hole 4 of the first material 1. Since the boundary portion 10 with the three materials 3 is also softened and stirred while applying frictional heat, the first material 1 side that is not particularly softened is joined without applying excessive pressure on the first material 1 side. It is possible to cope with the relatively large plate thickness of the first material 1, the second material 2, and the third material 3, and the bonding can be realized in a wide range from a thin plate to a thick plate. Further, the occurrence of quality defects such as cracks and deformations can be avoided in advance.

  In addition, the plate | board thickness of the 2nd material 2 piled up on the 1st material 1 is too thin, and the 2nd material 2 which should enter into the joining hole 4 is insufficient, The pin part 7 and the joining hole 4 with this 2nd material 2 When a situation occurs in which the gap is not fully filled, as shown in FIG. 5, a raised portion 2a is integrally formed on the surface on the second material 2 side immediately above the joint hole 4 of the first material 1. Or another piece of second material (not shown) is added as the raised portion 2a to partially increase the plate thickness, thereby compensating for the material shortage between the pin portion 7 and the joint hole 4. What is necessary is to make sure that the gap is filled with the second material 2.

  At this time, if the size of the raised portion 2a is accommodated within the outer diameter D of the shoulder portion 9 of the welding tool 8, the shoulder portion 9 softens and flattens the raised portion 2a without remaining, The final top surface shape of the second material 2 can be made flat.

  Furthermore, since the first material 1, the second material 2 and the third material 3 are firmly joined without an inclusion such as an adhesive, workability and working environment as in the case where an adhesive is used. In addition, it is possible to realize a joining with excellent recyclability that facilitates separation work during recycling.

  Therefore, according to the above embodiment, since there is no projection of a projection such as a bolt or a nut in the case of bolt fastening, the design restrictions can be relieved greatly, and the looseness or drop-off as in the case of bolt fastening can be achieved. In addition, it is possible to eliminate the occurrence of quality defects such as cracks and deformation, as well as workability and work environment. It is possible to achieve an excellent effect of being able to perform bonding with excellent recyclability while maintaining good.

  Further, the material joining method of the present invention may be configured such that the first material 1 is sandwiched between the second material 2 and the third material 3 as the bifurcated end portions of the same material, as shown in FIG. In this case, the joint of the first material 1 connected with the same thickness is formed by forming the end of the first material 1 into a convex shape that fits into the bifurcated shape of the second material 2 and the third material 3. It is possible to make a structure.

  In each of the embodiments described above, the bonding hole 4 is formed in a spot shape in the first material 1, and the bonding tool 8 is positioned at one point corresponding to the bonding hole 4 to perform spot bonding. As described above, the bonding hole 4 in FIGS. 1 to 6 is formed in a slit shape extending in a direction perpendicular to the drawing, and the bonding tool 8 is moved in the longitudinal direction of the bonding hole 4. It is also possible to perform continuous joining.

  In such continuous joining, the joining tool 8 moves while rotating so that the space between the joining start end and the joining end is filled with the softened second material 2 sequentially. In the end, it is only necessary to leave a hole at the end, and the finish is relatively good.

  The material joining method according to the present invention is not limited to the above-described embodiment. The first material, the second material, and the third material may not necessarily be different materials. Even if the two materials and the third material are the same type of material, the same joining method may be applied, and the first material may be any material as long as the joining hole can be drilled, The second material and the third material may be any material that can be locally softened in a solid state by frictional heat, and other than the metal material, a polymer material or the like can be appropriately employed, and other aspects of the present invention. Of course, various changes can be made without departing from the scope of the invention.

It is sectional drawing which shows an example of the form which implements this invention. It is sectional drawing which shows the state which descended, rotating the joining tool of FIG. It is sectional drawing which shows the state which the pin part of the joining tool of FIG. 2 reached | attained 3rd material. It is sectional drawing which shows the state which pulled up the joining tool from the state of FIG. It is sectional drawing which shows the example which formed the protruding part in the surface of the 2nd material side. It is sectional drawing of the example which used the bifurcated edge part of the same material as the 2nd material and the 3rd material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st material 2 2nd material 2a Raised part 3 3rd material 4 Joining hole 5 Groove part 5 'Mountain part 6 Recessed part 7 Pin part 8 Joining tool 9 Shoulder part 10 Boundary part

Claims (5)

A first material in which a joint hole is previously drilled and a groove portion is formed in advance on the inner side surface of the joint hole is sandwiched between the second material and the third material so as to cover the joint hole. Friction generated between the second material and the pin portion by placing a joining tool having an insertable pin portion corresponding to the joining hole, pressing the pin portion against the second material while rotating the joining tool The second material is softened locally in the solid state by heat to enter the first material joining hole, and a crest that fits with the groove is formed on the second material side that has entered the joining hole. be Rutotomoni, the pin portion also said third material brought remain localized softening of the solid phase by frictional heat against the third material, the second material in which penetrate into the joint hole and the third material After stirring the boundary part, pull out the welding tool and harden the boundary part. First material and the bonding method of the second material and material, characterized by joining the third material in three-ply Te. The material joining method according to claim 1, wherein a portion corresponding to the joining hole of the first material on the second material side is partially increased in thickness to compensate for material shortage. The material joining method according to claim 1 or 2, wherein the first material is sandwiched by using a bifurcated end portion of the same material as a second material and a third material. 4. The spot bonding is performed by spotting a joining hole in the first material in a spot shape and positioning a joining tool at one point corresponding to the joining hole. Material joining method. The material according to claim 1, 2, or 3, wherein a bonding hole is formed in a slit shape in the first material, and continuous bonding is performed by moving a bonding tool in a longitudinal direction of the bonding hole. Joining method.

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