JP5355048B2 - Manufacturing method of bonded structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a bumper structure by joining a bumper stay to a bumper beam through electromagnetic molding, which can secure joining force required between the bumper beam and the bumper stay even when the front wall and the outer wall of the bumper beam are reduced in thickness and input energy during electromagnetic molding needs to be suppressed. <P>SOLUTION: A stay intermediate material 3A having a shaft flange 18 along a shape of a circumferential edge of an opening at a front surface side of a burring hole 13 is preliminarily generated by expanding one end of a cylindrical extruded member of an aluminum alloy. The burring hole 13 is formed at the crushed end of the bumper beam 2, a shaft part 15 of a stay stock 3A is passed through the burring hole 13 from a front side, and the shaft flange 18 is made to abut on the opening at the front surface side of the burring hole 13. The stay stock 3A is expanded by electromagnetic molding at that state, the shaft part 15 is stuck to the burring hole 13, and the rear side of the burring hole 13 is protruded in an outer diameter direction to form a protrusion 19. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  According to the present invention, a hole penetrating a metal member is formed, a tubular member made of a tubular aluminum alloy extruded material is inserted into the hole, and the tubular member is expanded by electromagnetic forming so that an inner periphery of the hole is formed. The present invention relates to a method for manufacturing a bonded structure by bringing the two into close contact with each other and bonding them together.

In Patent Documents 1 and 2, holes penetrating in the front-rear direction are formed in the front and rear walls of the left and right ends of a bumper beam made of an aluminum alloy extruded material having a closed cross section, and the holes made of a cylindrical aluminum alloy extruded material are formed in the holes. Insert the material, make the front end slightly protrude forward from the hole in the front wall, and in that state expand the stay material by electromagnetic forming and join it to the bumper beam to produce a bumper structure consisting of the bumper beam and bumper stay It is described to do.
In Patent Documents 3 to 5, a hole is formed in a flat flange member, a shaft member made of a tubular aluminum alloy extruded material is inserted into the hole, and the front end is slightly protruded forward from the hole. In addition, it is described that a shaft member is expanded by electromagnetic forming and joined to the metal member to produce a flanged shaft member.

In the bumper structures disclosed in Patent Documents 1 and 2, the stay material is expanded by electromagnetic forming, and is joined to the inner surface of the hole formed in the front and rear walls of the bumper beam so that the stay material is joined to the bumper beam. Is expanded in a flange shape, and the portions protruding between the front and rear walls and the rear side of the rear wall project in the outer diameter direction, thereby strengthening the joining. Even in the shaft members with flanges of Patent Documents 3 to 5, the shaft member is joined to the flange member by expanding the tube by electromagnetic forming and closely contacting the inner peripheral surface of the hole formed in the flange member. Further, the front end of the shaft member is Bonding is strengthened by expanding into a flange shape and projecting a portion protruding rearward from the flange member in the outer diameter direction.

JP 2007-284039 A JP 2004-237818 A JP 2005-152920 A JP 2005-313184 A JP 2005-262261 A

As shown in FIG. 19A, a tubular member 63 is inserted into a hole 62 formed in a metal member 61, its front end is projected from the hole 62, and in this state, the tubular member 63 is expanded by electromagnetic forming. Then, as shown in FIG. 19 (b), the front end of the cylindrical member 63 is expanded to form an expanded portion (shaft flange) 64, and at the same time, an overhanging portion on the rear side of the hole 62 of the metal member 61. 65 is formed. The input energy for electromagnetic forming at this time is set to a level at which the hole 62 formed in the metal member 61 is not substantially enlarged in diameter and the peripheral portion of the hole 2 is not substantially deformed. Is sufficiently large, the shaft flange can be expanded into a flat shape along the front-side opening peripheral edge 61a (portion indicated by the arrow) of the hole 62. On the contrary, if the input energy is small, the shaft flange 64 does not expand as much as the opening peripheral edge portion 61a, but only expands in a morning glory shape as shown in FIG. Even in this case, the overhanging portion 65 is formed.

As shown in FIG. 19, when the front end of the cylindrical member 63 is cut perpendicular to the axial direction, the shaft flange 64 can be expanded almost uniformly along the circumferential direction. When the front end of the cylindrical member (stay material) is cut obliquely as in the bumper structure described in 1), it is relatively difficult to uniformly expand the shaft flange along the circumferential direction. In other words, when a stay material with the front end inclined in the same way is inserted into a hole formed in the inclined end of the bumper beam and the stay material is expanded by electromagnetic forming, the acute angle side of the front end of the stay material (in the vehicle width direction of the bumper beam) In the central part), the eddy current generated during electromagnetic forming is weak, so that the shaft flange is difficult to expand on the acute angle side. Therefore, even if it expands almost flat on the obtuse angle side (the end of the bumper beam in the vehicle width direction), it may only expand in the morning glory shape on the acute angle side as shown in FIG.

Furthermore, when the front surface side of the metal member is not flat, for example, as described in Patent Document 4, even when there is a step in the opening periphery of the hole, the entire circumference of the shaft flange is the shape of the opening periphery. In many cases, it is difficult to form the shape along the shape.

The shaft flange formed at the end of the cylindrical member does not expand to a shape that follows the shape of the front-side opening peripheral edge of the hole of the metal member, but expands in a morning glory shape as shown in FIG. Even in the opened position, the joining of the metal member and the cylindrical member is ensured. However, it is more desirable that the shaft flange is expanded in a shape along the opening peripheral edge of the hole, because the joining of both can be made more reliable.
Further, the shaft flange (see FIG. 19B) that protrudes forward in a morning glory shape may be a cause of damage to other members or as an unnecessary protrusion. Further, when the joint structure is a bumper structure, if the shaft flange protrudes forward from the front wall of the bumper beam, the sharp tip may damage the bumper cover at the time of collision. These problems are solved by expanding the shaft flange into a shape along the opening periphery of the hole.

On the other hand, for example, in the case of a bumper structure, since the aluminum alloy extruded material can freely set the cross-sectional shape and the thickness distribution in the cross section, the range that satisfies the required impact energy absorption characteristics for the aluminum alloy extruded material of the bumper beam Among them, various cross-sectional shapes have been studied for reducing the weight of the vehicle body, and there is a current situation that the thickness is further reduced. As the bumper beam becomes thinner, the strength of the hole formed in the bumper beam naturally decreases. In order to prevent the hole with reduced strength from receiving pipe expansion of the cylindrical member (stay material) during joining by electromagnetic forming, and to prevent the hole itself from substantially expanding in diameter and from deforming the periphery of the hole, electromagnetic forming is introduced. It is necessary to reduce energy. Therefore, as the bumper beam is made thinner, a shaft flange that expands in a morning glory shape and an overhang can be formed during electromagnetic forming, but a shaft flange that expands into a shape along the peripheral edge of the hole is formed. It will be difficult to do. The orientation of the metal member to be thin (with light weight) is not limited to the bumper structure.

Further, as the metal member is further thinned, it may be difficult to form the shaft flange itself by electromagnetic forming at the time of joining. As mentioned earlier, when the thickness of the metal member is small and the strength of the hole drilled in the metal member is small, the hole does not easily expand during electromagnetic forming, or the hole periphery does not deform easily. Thus, it is necessary to set the input energy at the time of electromagnetic forming small, but the input energy that can still be joined, specifically, the input that can expand the end of the cylindrical member to form the shaft flange Energy is necessary. However, as shown in FIG. 20, the tubular member 63 is deformed into an irregular shape as if the low-periphery hole peripheral part 61a is turned up by the expanding force that acts on the peripheral part 61a of the metal member 61 during electromagnetic forming. It may occur that the tube flange 64 and the overhanging portion 65 (see FIG. 19B) are not formed by expanding the tube as a whole. Such a phenomenon is likely to occur particularly when the metal member is made of a material having good conductivity, for example, a 6000 series aluminum alloy.

The present invention has been made in view of the above-mentioned various problems that occur when a tubular structure is joined to a metal member by using electromagnetic forming, and the holes are mainly produced as the thickness is reduced. An object is to ensure that the metal member and the cylindrical member can be joined even when the strength is insufficient and therefore it is necessary to suppress the input energy during electromagnetic forming.

The present invention forms a hole penetrating through a metal member, inserts a cylindrical member made of a cylindrical aluminum alloy extruded material into the hole, expands the cylindrical member by electromagnetic forming, and forms an inner periphery of the hole. In connection with an improvement in a method of manufacturing a bonded structure by bonding the metal member and the cylindrical member to each other in close contact with the surface, one end of the cylindrical aluminum alloy extruded material is expanded in advance to form a shaft flange. A tubular member having the tubular member is inserted, the shaft portion of the tubular member is inserted into the hole, the shaft flange is brought into contact with the opening portion of the hole, and the tubular member is expanded by the electromagnetic forming in this state. It is characterized by that. In the present invention, the joint structure includes, for example, a bumper structure (see Patent Documents 1 and 2) and a shaft member with a flange (see Patent Documents 3 to 5). In addition to the aluminum alloy extruded material, the metal member includes a member formed from an aluminum alloy plate, an iron member, and the like.

The present invention can take the following specific forms, for example.
(1) The said shaft flange is expanded so that it may have a shape substantially along the shape of the opening peripheral part of the hole of the said metal member.
(2) The metal member is a plate-like member, and the tubular member is expanded by electromagnetic forming so that the shaft portion is brought into close contact with the inner peripheral surface of the hole, and at the same time from the plate-like member to the opposite side of the shaft flange. Project the protruding shaft part in the outer diameter direction. In this case, the hole is a burring hole that has been burred from the side on which the shaft flange abuts.
(3) The metal member has a closed cross section, and the cylindrical member is expanded by electromagnetic forming so that the shaft portion is in close contact with the inner peripheral surface of the hole. Project the shaft protruding to the opposite side in the outer diameter direction.
(4) Forming the shaft flange by expanding one end of the cylindrical aluminum alloy extruded material by electromagnetic forming. In this case, the shaft flange is further shaped by pressing.

Further, the present invention provides a cylinder-shaped hole in the bumper beam, which is formed of a closed cross-section having a front wall on the collision surface side and a rear wall on the vehicle body side, and has holes penetrating in the front-rear direction at both ends. A bumper stay tubular member made of an aluminum alloy extruded material is inserted, and the tubular member is expanded by electromagnetic forming to closely contact the inner peripheral surface of the hole, and the bumper beam and the tubular member are joined to form a bumper structure. Regarding the improvement of the method of manufacturing a body, a cylindrical member having a shaft flange is created by expanding one end of a cylindrical aluminum alloy extruded material in advance, and the shaft portion of the cylindrical member is formed from the front wall side. The shaft member is inserted into the hole, the shaft flange is brought into contact with the opening, and the tubular member is expanded by the electromagnetic forming in this state. In the present invention, regardless of the front side and the rear side of the vehicle, the collision surface side is the front and the opposite side is the rear.

The present invention can take the following specific forms, for example.
(5) The shaft flange is expanded so as to have a shape substantially along the shape of the opening peripheral edge of the hole on the front wall side.
(6) The shape of the closed section for the bumper beam is made of an aluminum alloy extruded material.
(7) The tubular member is expanded by electromagnetic forming so that the shaft portion is brought into close contact with the inner peripheral surface of the hole, and at the same time, the shaft portion protruding between the front and rear walls and the rear side of the rear wall is projected in the outer diameter direction. Make it.
(8) Both ends of the bumper beam are crushed in the front-rear direction, and the holes are punched in the front and rear walls overlapped by the crushing process. In this case, the hole is a burring hole and is formed by burring from the front side after punching.
(9) One end of the tubular aluminum alloy extruded material is expanded by electromagnetic forming to form the shaft flange. In this case, the shaft flange is further shaped by pressing.

According to the present invention, before the tubular member is expanded by electromagnetic forming and joined to the metal member, the end of the tubular member is expanded in advance to form the shaft flange. There is no need to form a new shaft flange in the molding, and therefore, the joining of the metal member and the cylindrical member is ensured even if the input energy during electromagnetic molding is suppressed.
In addition, since the shaft flange is formed in advance on the cylindrical member, the molding method can be freely selected, and the shape exactly along the shape of the opening peripheral edge of the hole for contacting the shaft flange, for example, a flat shape, It is easy to form into a stepped shape. Thus, by making the shaft flange a shape along the peripheral edge of the opening, the metal member and the cylindrical member can be more reliably joined. Further, in this case, the shaft flange can be prevented from causing damage to other members or being obstructed as a useless protrusion, and if the joint structure is a bumper structure, the shaft flange may damage the bumper cover. Also disappear.
Other functions and effects of the present invention will be specifically described in the following [Best Mode for Carrying Out the Invention] section.

First, with reference to FIGS. 1-11, the example of the manufacturing method of the junction structure (bumper structure) which concerns on this invention is demonstrated concretely.
A bumper structure 1 shown in FIG. 1 is bonded to both left and right ends of a bumper beam 2 made of an aluminum alloy extruded material having a closed cross-sectional shape shown in FIG. 2 and a cylindrical aluminum alloy extruded material. It consists of bumper stay 3.
As shown in FIG. 2, the cross section of the aluminum alloy extruded material constituting the bumper beam 2 is a front wall 4 on the collision surface side, a rear wall 5 on the vehicle body side, and an upper wall connecting the front wall 4 and the rear wall 5. 6 and a lower wall 7, and a bead 4 a (stepped portion) is formed at the center of the front wall 4 and protrudes to the front side. The bead 4 a of the front wall 4 and the upper and lower The part of the predetermined width and the central part of the rear wall 5 are considerably thinned.

The bumper beam 2 has a central portion in the vehicle width direction parallel to the vehicle width direction, and both end portions are bent rearward (vehicle body side) and inclined, and most of the inclined end portions are crushed in the front-rear direction by pressing. Has been processed. This crushing process is performed by placing the bumper beam 2 on the lower mold 8 having the receiving surface corresponding to the front side shape of the front wall 4 with the front wall 4 side facing downward, as indicated by phantom lines in FIG. And an upper mold having a punching surface that is slightly narrower than the vertical width of the front wall 4 and the rear wall 5 and corresponds to the shape of the rear side of the rear wall 5 when the rear wall 5 is brought into close contact with the front wall 4 9 is lowered (see the white arrow), the rear wall 5 is pushed between the upper wall 6 and the lower wall 7, and the rear wall 5 is moved forward from the rear side (vehicle body side) toward the front side (collision side). This is performed until the back surface of 4 is touched. That is, only the rear wall 5 side is pushed forward by the crushing process without changing the position of the front wall 4 side and before the crushing process.

Since this crushing process is performed inside the upper wall 6 and the lower wall 7, as shown in FIG. 3, the upper wall 6 and the lower wall 7 remain crushed in a slightly expanded state, and overlap the front wall 4. On the top and bottom of the rear wall 5, a rib-like portion 11 mainly constituted by the upper wall 6 and a rib-like portion 12 mainly constituted by the lower wall 7 are formed.
As shown in the end view of FIG. 3, in the crushed portion, the front wall 4 and the rear wall 5 overlap each other in the close contact state over almost the entire width in the vertical direction, and above and below the overlapped front wall 4 and rear wall 5. A rib-like portion 11 mainly constituted by the upper wall 6 and a rib-like portion 12 mainly constituted by the lower wall 7 are formed. A portion where the bumper beam 2 is crushed by the overlapped front wall 4 and rear wall 5 and the upper and lower rib-like portions 11 and 12 forms a groove shape whose rear side is opened as a whole. Moreover, each rib-shaped part 11 and 12 has a hollow cross section. As shown in FIG. 1, there is a transition region where the degree of crushing changes between a place where the front wall 4 and the rear wall 5 are overlapped and a place where the crushing process is not carried out.

Holes penetrating the front wall 4 and the rear wall 5 in the front-rear direction are punched from the front side or the rear side by press punching in the front and rear walls 4, 5 that are crushed and overlapped at both ends of the bumper beam 2. Further, burring is performed on the hole from the front side. Since the front wall 4 and the rear wall 5 are in close contact with each other at this location, it is possible to perform punching and burring by pressing from one side as if a single plate.
When performing such drilling and burring, it is desirable that the front wall 4 and the rear wall 5 are in close contact with each other, but some clearance is allowed between both walls (springback after crushing) May cause gaps). The point is that any gap that allows drilling and burring from one side without any problem is acceptable.

As shown in FIGS. 4 and 5, the formed burring hole 13 penetrates the front wall 4 and the rear wall 5 in the front-rear direction and has a diameter that exceeds the bead 4 a in the vertical direction. A hole flange 14 is formed to expand toward the side. The hole flange 14 includes a front wall 4 and a rear wall 5, and the front wall 4 and the rear wall 5 are in close contact with each other. If the gap is too large, the front wall 4 is easily gnawed by a punch (not shown) during burring. The wall 4 is separated from the rear wall 5, and the front wall 4 is deformed (disintegrated in shape) around the hole flange 14. However, if the gap is about ½ or less of the burring height (depth of the burring hole 13), drilling and burring can be performed without any particular trouble. When the front wall 4 and the rear wall 5 are thin, if burring is performed using a tapered punch, an outward curvature (curling) may occur in the formed hole flange. Such burring holes are also included in the burring holes referred to in the present invention.
The rear end of the hole flange 14 is substantially in the same plane, and the burring height is large at the portion of the front wall 4 that hangs on the bead 4a and is small at the portion of the front wall 4 that hangs on the flat portion 4b (up and down of the bead 4a).

The bumper stay 3 is made of a cylindrical aluminum alloy extruded material, and a shaft portion 15 facing in the longitudinal direction of the vehicle body has a substantially circular cross section, and is fixed to the front end of a side member (not shown) at the rear end of the shaft portion 15. A flange 16 is formed perpendicular to the longitudinal direction of the vehicle body.
As shown in FIG. 6, the front portion of the shaft portion 15 (the portion involved in the joining) is inserted into the burring hole 13 and expanded by electromagnetic forming to closely contact the inner peripheral surface of the burring hole 13 (the front side is A bulging portion 19 projecting in the outer diameter direction on the rear side of the rear end of the burring hole 13, and projecting forward of the burring hole 13 at the front end of the shaft portion 15. A shaft flange 18 that expands along the front surface is formed. Because the bumper stay 3 has the above structure, the bumper stay 3 is firmly joined to the bumper beam 2.

The manufacturing (joining) of the bumper structure including the bumper beam 2 and the bumper stay 3 is performed in the following procedure.
First, as shown in FIG. 7, a cylindrical aluminum alloy extruded material having an outer diameter close to the inner diameter of the burring hole 13 is widened, and a shaft flange 18 is formed at the front end of the shaft portion 15. A shaped member (stay intermediate material) 3A is prepared. The back surface side of the shaft flange 18 has a slightly complicated shape substantially along the shape of the inner peripheral surface where the burring hole 13 is expanded and the peripheral edge portion of the front wall side opening.

The shaft flange 18 of the cylindrical member 3A can be formed by a method described in, for example, Japanese Patent Application Laid-Open No. 2004-042066. Briefly, this method inserts a cylindrical aluminum alloy extruded material into a through hole of a mold for electromagnetic forming (divided mold that can be divided into a plurality of parts in the vertical direction), and the front end is an end face of the through hole. It can be formed by projecting a predetermined length from the main body and expanding a portion mainly projecting from the through hole by electromagnetic forming. The said end surface is also a molding surface, and is formed in the shape matched with the shape of the inner peripheral surface which the burring hole 13 expanded, and the front wall side opening peripheral part.
A portion of the aluminum alloy extruded material protruding from the through hole by electromagnetic forming expands instantaneously and is struck against the end face, thereby having a shaft flange 18 that is substantially perpendicular to the axial direction and flat at the front end of the shaft portion 15. A cylindrical member 3A is formed. If the shape of the peripheral edge of the opening on the front wall side of the burring hole 13 (having a flat portion or a stepped portion) cannot be accurately obtained only by electromagnetic forming, the shaft flange 18 can be obtained by appropriate means such as press forming using a mold. Can be appropriately shaped.

Next, as shown in FIGS. 8 and 9, the shaft portion 15 of the cylindrical member 3 </ b> A is inserted into the burring hole 13 from the front wall side, and the shaft flange 18 is brought into contact with the front wall side opening peripheral portion of the burring hole 13. In this state, an electromagnetic forming coil 21 (see FIG. 8) indicated by a virtual line is inserted into the cylindrical member 3A, and the range from the front end of the cylindrical member 3A to the rear side of the burring hole 13 is expanded by electromagnetic forming. . At this time, it is possible to surround the rear portion of the shaft portion 15 (the portion not involved in the joining) with a mold to prevent excessive tube expansion.
As shown in FIGS. 10 and 11, the shaft portion 15 of the cylindrical member 3 </ b> B after electromagnetic forming is in close contact with the inner peripheral surface of the burring hole 13 (contact portion 17), and in the outer diameter direction on the rear side of the burring hole 13. On the other hand, the shaft flange 18 is in close contact with the front wall side opening peripheral edge of the burring hole 13, and the tubular member 3 </ b> B is joined to the bumper beam 2.
In addition, the burring hole 13 has an effect of increasing the contact strength with the bumper stay 3 by increasing the contact area with the bumper stay 3 and an effect of increasing the strength and rigidity of the hole peripheral portion by the hole flange 14 as compared with a simple punching hole. Further, the fact that the burring hole 13 is formed at the location where the front wall 4 and the rear wall 5 overlap (the apparent plate thickness increases) also contributes to the strength and rigidity of the hole peripheral portion.

  In this electromagnetic forming, the shaft flange 18 does not need to be particularly formed, so that the input energy can be mainly suppressed to a level necessary for forming the overhang portion 19. In addition, since the burring hole 13 is overlapped with the front wall 4 and the rear wall 5, the burring hole 13 is formed by electromagnetic forming in spite of the small thickness of the front wall 4 and the rear wall 5. It is not necessary to substantially increase the diameter and deformation of the peripheral portion of the burring hole 13. Moreover, the shaft flange 18 is in close contact with the opening peripheral edge of the burring hole 13 having a stepped portion or a flat portion. 10 and 11 show a state in which the rear side (front end side) of the hole flange 14 after electromagnetic forming is slightly expanded in the outer diameter direction as compared with FIGS. The expansion of the hole flange 14 in the outer diameter direction is due to the applied pressure of the tubular member 3B expanded by electromagnetic forming, whereby the overhanging portion 19 of the shaft portion 16 is easily extended in the outer diameter direction, and An inward reaction force is applied from the elastically deformed hole flange 14 to the contact portion 17 of the cylindrical member 3B, and rather, the joining property between the cylindrical member 3B and the bumper beam 2 is improved.

After joining by electromagnetic forming, the mounting flange 16 is formed at the rear end of the tubular member 3B. The mounting flange 16 can be formed by expanding the pipe by electromagnetic forming in the same manner as the shaft flange 15 described above, and can be flattened together with press forming as necessary. The tubular member (bumper stay 3) after the mounting flange 16 is molded is shown in FIG. In this electromagnetic forming, it is not necessary to suppress the input energy (however, the input energy does not substantially reach the joint), and the mounting flange 16 that is substantially perpendicular to the axial direction of the cylindrical member 3B is provided. It can be set to a high level that can be molded.
The mounting flange 16 can be formed before joining by electromagnetic forming or simultaneously with joining by electromagnetic forming. As an alternative to the mounting flange 16, for example, as described in Patent Documents 3 to 5, a plate-like flange member can be joined to the rear end of the tubular member 3B.

Next, an example in which the mounting flange 16 is formed simultaneously with the joining by electromagnetic forming will be described with reference to FIG.
In FIG. 12, the cylindrical member 3 </ b> A (stay intermediate material) is created by expanding the end of the cylindrical aluminum alloy extruded material and expanding the entire length at the same time. It consists of a shaft flange 18 formed at the front end. The back surface side of the shaft flange 18 has a shape substantially in line with the shape of the inner peripheral surface where the burring hole 13 is expanded and the peripheral edge of the front wall side opening. This cylindrical member 3A can be created by electromagnetic forming or the like in the same manner as the cylindrical member 3A shown in FIG.

As shown in FIG. 12, the shaft portion 15 of this cylindrical member 3A is inserted into the burring hole 13 from the front wall side, the shaft flange 18 is brought into contact with the front wall side opening peripheral portion of the burring hole 13, and the state Then, the electromagnetic forming coil 21 indicated by the phantom line is inserted into the cylindrical member 3A, and the entire length of the cylindrical member 3A is expanded by electromagnetic forming. At this time, the rear portion (portion not involved in joining) of the cylindrical member 3A is surrounded by the electromagnetic molding die 22 having a through hole, and the rear end of the cylindrical member 3A protrudes from the end surface of the through hole by a predetermined length. Let me. In this case, the input energy for electromagnetic forming is set to a high level at which the mounting flange 16 can be formed.

Even if the input energy of electromagnetic forming is set to a high level, the distance between the coil 21 and the cylindrical member 3A is widened toward the front end. Therefore, in this electromagnetic forming, the front portion of the shaft portion 15 of the cylindrical member 3A. Only the tube expansion force at the level necessary for forming the overhanging part is mainly applied to the (parts involved in the joining), and the rear part of the shaft part 15 (part not involved in the joining), particularly the rear end part is for mounting It is possible to apply a large tube expansion force that enables the flange to be formed. Therefore, the diameter expansion of the burring hole 13 and the deformation of the peripheral portion of the burring hole 13 do not have to be substantially caused by electromagnetic forming.
Note that the mounting flange formed by electromagnetic forming can be shaped by pressing or the like as necessary.

Then, with reference to FIGS. 13-15, the example of the manufacturing method of another joining structure (bumper structure) which concerns on this invention is demonstrated.
A bumper structure 31 shown in FIG. 13 is similar to the bumper structure 1 shown in FIGS. 1 to 11 (see FIG. 6), and a bumper beam 32 made of an aluminum alloy extruded material having a closed cross-sectional shape, and a cylindrical aluminum alloy extruded material. The bumper stay 33 is made of a material and joined to both left and right ends of the bumper beam 32.

  The cross section of the aluminum alloy extruded material constituting the bumper beam 32 includes a front wall 34 on the collision surface side, a rear wall 35 on the vehicle body side, an upper wall (not shown) connecting the front wall 34 and the rear wall 35, and a lower wall. The front wall 34 and the rear wall 35 are substantially thin. As with the bumper beam 2 of the bumper structure 1 shown in FIGS. 1 to 11, the bumper beam 32 is inclined by bending the center portion in the vehicle width direction parallel to the vehicle width direction and bending both end portions to the rear side (vehicle body side). doing. At both ends of the bumper beam 32, holes 38 and 39 (see FIG. 14) penetrating the front wall 34 and the rear wall 35 are formed. In addition, the both ends of the bumper beam 32 are not crushed.

The bumper stay 33 is made of a cylindrical aluminum alloy extruded material, and a front portion (portion involved in joining) of the shaft portion 41 facing in the longitudinal direction of the vehicle body is inserted into holes 38 and 39 formed in the bumper beam 32, and the shaft A mounting flange 42 fixed to the front end of a side member (not shown) is formed at the rear end of the portion 41 so as to be perpendicular to the longitudinal direction of the vehicle body.
The front portion of the shaft portion 41 (the portion involved in the joining) is an outer portion between the front wall 34 and the rear wall 35 that is in close contact with the inner peripheral surface of the hole 38 on the front wall side and the hole 39 on the rear wall side. It has a projecting portion 44 projecting in the radial direction and a projecting portion 45 projecting in the outer diameter direction on the rear side of the rear wall 34, and projects forward from the hole 38 on the front wall side to the front end of the shaft portion 41. A shaft flange 43 that extends along the front surface of the wall 34 is formed. Since the bumper stay 33 has the above structure, the bumper stay 33 is firmly joined to the bumper beam 32.

The bumper structure 31 including the bumper beam 32 and the bumper stay 33 is manufactured (joined) in the following procedure.
First, as shown in FIG. 14, the end of the cylindrical aluminum alloy extruded material having an outer diameter close to the inner diameter of the holes 38 and 39 is expanded, and a shaft flange 43 is formed at the front end of the shaft portion 41. A cylindrical member (stay intermediate material) 33A is prepared. The back surface side of the shaft flange 43 has a flat shape substantially along the shape of the opening peripheral edge portion of the hole 38 on the front wall side. The cylindrical member 33A can be created by electromagnetic forming similarly to the cylindrical member 3A shown in FIG. Further, when the shape (flat surface) of the opening peripheral portion of the hole 38 on the front wall side cannot be accurately obtained only by electromagnetic molding, the shaft flange 43 is appropriately shaped by appropriate means such as press molding using a mold. can do.

Next, the shaft portion 41 of the cylindrical member 33A is inserted into the holes 38 and 39 from the front wall side, and the shaft flange 43 is brought into contact with the opening peripheral edge of the hole 38 on the front wall side. Is inserted into the cylindrical member 33A, and the range from the front end of the cylindrical member 33A to the rear side of the rear wall 35 is expanded by electromagnetic forming. At this time, the rear portion of the shaft portion 41 (portion that does not participate in joining) can be surrounded by a mold to prevent excessive tube expansion.
As shown in FIG. 15, the shaft portion 41 of the cylindrical member 33 </ b> B after electromagnetic forming is in close contact with the inner peripheral surface of the hole 38 on the front wall side and the hole 39 on the rear wall side, and the front wall 34 and the rear wall 35 are In the middle and on the rear side of the rear wall 35, it projects in the outer diameter direction (projections 44, 45). On the other hand, the shaft flange 43 is in close contact with the opening peripheral edge of the hole 38 on the front wall side, and the cylindrical member 33B is a bumper beam. 32.

In this electromagnetic forming, the shaft flange 43 does not have to be particularly formed, so that the input energy can be mainly suppressed to a level necessary for forming the overhang portions 44 and 45. Therefore, although the plate thickness of the front wall 34 and the rear wall 35 is small, the diameters of the holes 38 and 39 and the deformation of the hole peripheral portion are not substantially generated by electromagnetic forming. Moreover, the shaft flange 43 is flat and is in close contact with the opening peripheral edge of the hole 38 on the front wall side.
After joining by electromagnetic forming, a mounting flange 42 is formed at the rear end of the cylindrical member 33B. The mounting flange 42 can be formed by the same method as that performed on the tubular member 3B of the bumper structure 1 shown in FIG.

Next, with reference to FIGS. 16-18, the example of the manufacturing method of another joining structure (shaft member with a flange) which concerns on this invention is demonstrated.
The flanged shaft member shown here is a bumper stay 51, and as shown in FIG. 16, is composed of a plate-like member 52 and a cylindrical member 53 joined thereto by electromagnetic forming. The plate-like member 52 is a flange that is bolted, for example, to the front end of the side member of the automobile body, and the mounting flange 54 that is formed at one end of the cylindrical member 53 is a flange that is bolted, for example, to the rear wall of the bumper beam. is there.

The plate-like member 52 is made of a thin plate material, and a recess is press-formed concentrically at the center, and a burring hole 55 is formed from the front side toward the rear side at the center. In addition, let the side in which the shaft flange mentioned later is located be the front, and the other side is the back.
The cylindrical member 53 is made of a cylindrical aluminum alloy extruded material, a front portion of the shaft portion 56 (portion involved in joining) is inserted into the burring hole 55, and the mounting flange 54 is provided at the rear end of the shaft portion 56. It is formed perpendicular to the axial direction.
The front portion of the shaft portion 56 (the portion involved in joining) includes a close contact portion 56 that is in close contact with the inner peripheral surface of the burring hole 55 of the plate-like member 52 and a tension that protrudes in the outer diameter direction on the rear side of the plate-like member 52. A shaft flange 58 having a protruding portion 59 and projecting forward from the burring hole 55 and expanding along the front surface of the plate-like member 52 is formed at the front end of the shaft portion 56. Since the cylindrical member 53 has the above structure, the cylindrical member 53 is firmly joined to the plate member 52.

Manufacture (joining) of the bumper stay 51 including the plate-like member 51 and the tubular member 53 is performed in the following procedure.
First, as shown in FIG. 17, the end of the cylindrical aluminum alloy extruded material having an outer diameter close to the inner diameter of the burring hole 55 is expanded, and a shaft flange 58 is formed at the front end of the shaft portion 56. A cylindrical member 53A is created. The rear surface side of the shaft flange 58 has a shape along the shape of the concave portion (opening peripheral edge portion of the burring hole 55) on the front surface side of the plate-like member 52. The cylindrical member 53A can be created by electromagnetic forming similarly to the cylindrical member 3A shown in FIG. Further, when the shape (flat surface) of the opening peripheral portion of the burring hole 55 cannot be accurately obtained only by electromagnetic forming, the shaft flange 58 can be appropriately shaped by appropriate means such as press forming using a mold. it can.

Subsequently, as shown in FIG. 18, the shaft portion 56 of the cylindrical member 53A is inserted into the burring hole 55 from the front, and the shaft flange 58 is brought into contact with the opening peripheral edge of the burring hole 55. The electromagnetic forming coil is inserted into the cylindrical member 53A, and the range from the front end of the cylindrical member 53A to the rear side of the plate member 52 is expanded by electromagnetic forming. At this time, the rear portion of the shaft portion 56 (portion that does not participate in joining) can be surrounded by a mold to prevent excessive tube expansion.
As shown in FIG. 18, the shaft portion 56 of the cylindrical member 53 </ b> B after electromagnetic forming is in close contact with the inner peripheral surface of the burring hole 55, and projects in the outer diameter direction on the rear side of the plate-shaped member 52 (projected portion 58. On the other hand, the shaft flange 58 of the tubular member 53B is in close contact with the opening peripheral edge of the burring hole 55, and the tubular member 53B is joined to the plate member 52.

In this electromagnetic forming, the shaft flange 58 does not have to be particularly formed, so that the input energy can be mainly suppressed to a level necessary for forming the overhang portion 59. Therefore, even though the plate-like member 52 is thin and has low strength and rigidity, it is not necessary to cause the diameter expansion of the burring hole 55 or the deformation of the hole peripheral portion by electromagnetic forming. Moreover, the shaft flange 58 is flat and is in close contact with the opening peripheral edge of the burring hole 55 formed in the plate-like member 52.
After joining by electromagnetic forming, a mounting flange 54 is formed at the rear end of the cylindrical member 53B. The mounting flange 54 can be formed by the same method as that performed on the tubular member 3B of the bumper structure 1 shown in FIG.

  The bumper structure generally has a bolt hole for fixing the mounting flange to the side member and a work hole used when bolting the mounting flange to the side member. And omitted in the drawings. Bolt holes are also formed in the bumper stay flanges (plate members, mounting flanges), which are omitted in the above description and drawings. If necessary, the bolt holes and work holes may be formed at an appropriate stage of the manufacturing process.

It is a top view of the bumper structure concerning the present invention. It is AA sectional drawing of FIG. It is a BB end view of FIG. It is CC sectional drawing (before bumper stay joining) of the bumper beam of the bumper structure shown in FIG. FIG. 3 is an end plan sectional view of the bumper beam of the bumper structure shown in FIG. 1 (before bumper stay joining). It is a plane sectional view of the bumper structure shown in FIG. It is a perspective sectional view of the cylindrical member used for manufacture of the bumper structure shown in FIG. It is sectional drawing (DD cross section of FIG. 1) explaining the manufacturing method of the bumper structure shown in FIG. It is a plane sectional view explaining the manufacturing method of the bumper structure shown in FIG. It is sectional drawing (DD cross section of FIG. 1) explaining the manufacturing method of the bumper structure shown in FIG. It is a plane sectional view explaining the manufacturing method of the bumper structure shown in FIG. It is sectional drawing (DD cross section of FIG. 1) explaining another manufacturing method of the bumper structure shown in FIG. It is a plane partial sectional view of the edge part of another bumper structure concerning the present invention. FIG. 14 is a partial cross-sectional view illustrating a method for manufacturing the bumper structure shown in FIG. 13. FIG. 14 is a partial cross-sectional view illustrating a method for manufacturing the bumper structure shown in FIG. 13. It is sectional drawing of the joining structure (bumper stay) which concerns on this invention. It is sectional drawing explaining the manufacturing method of the joining structure shown in FIG. It is sectional drawing explaining the manufacturing method of the joining structure shown in FIG. It is sectional drawing before the electromagnetic forming (a) explaining the deformation | transformation form at the time of joining a metal member and a cylindrical member by electromagnetic forming, and (b) after electromagnetic forming. It is sectional drawing before the electromagnetic forming (a) explaining the deformation | transformation form at the time of joining a metal member and a cylindrical member by electromagnetic forming, and (b) after electromagnetic forming.

Explanation of symbols

1,31 Bumper structure 2,32 Bumper beam 3,33 Bumper stay 4,34 Bumper beam front wall 5,35 Same rear wall 6 Same upper wall 7,37 Same lower wall 13,55 Burring hole 15,41,56 Axes Portions 18, 43, 58 Shaft flanges 19, 44, 45, 59 Overhang 38, 39 holes

Claims (13)

A hole penetrating the metal member is formed, a cylindrical member made of a cylindrical aluminum alloy extruded material is inserted into the hole, and the cylindrical member is expanded by electromagnetic forming so as to adhere to the inner peripheral surface of the hole. In the method of manufacturing a joined structure by joining the metallic member and the tubular member, one end of the tubular aluminum alloy extruded material is expanded in advance by electromagnetic forming to form a shaft flange. A cylindrical member having a shaft flange is created, the shaft portion of the cylindrical member is inserted into the hole, the shaft flange is brought into contact with the opening of the hole, and the cylindrical member is electromagnetically molded in that state. The manufacturing method of the junction structure characterized by expanding by this. The method for manufacturing a joined structure according to claim 1 , further comprising shaping the shaft flange by press working. The method for manufacturing a joint structure according to claim 1 , wherein the shaft flange is expanded so as to have a shape substantially along a shape of an opening peripheral edge portion of the hole. The metal member is a plate-like member, and the cylindrical member is expanded by the electromagnetic forming so that the shaft portion is brought into close contact with the inner peripheral surface of the hole, and at the same time, the plate-like member is opposite to the shaft flange. The method of manufacturing a joined structure according to any one of claims 1 to 3, wherein a shaft portion protruding sideward is projected in an outer diameter direction. The method for manufacturing a joined structure according to claim 4 , wherein the hole is a burring hole that is burred from the side on which the shaft flange abuts. The metal member has a closed cross section, and the tubular member is expanded by the electromagnetic forming so that the shaft portion is in close contact with the inner peripheral surface of the hole, and at the same time, the shaft flange extends from the inside of the closed cross section and the closed cross section. The method of manufacturing a joined structure according to any one of claims 1 to 3, wherein a shaft portion projecting to the opposite side of the outer wall is projected in an outer diameter direction. It is made of a cylindrical aluminum alloy extruded material in the hole of the bumper beam, which is made of a closed cross-sectional shape having a front wall on the collision surface side and a rear wall on the vehicle body side, and has holes penetrating in the front-rear direction at both ends. In a method of manufacturing a bumper structure by inserting a cylindrical member for a bumper stay, expanding the tubular member by electromagnetic forming, closely contacting the inner peripheral surface of the hole, and joining the bumper beam and the tubular member advance one end of the cylindrical aluminum alloy extruded material by molding the flared shaft flange by electromagnetic forming to create a tubular member having the shaft flange, the shaft front wall side of the tubular member And the shaft flange is brought into contact with the opening of the hole on the front wall side, and the tubular member is expanded by the electromagnetic forming in this state. . The bumper structure manufacturing method according to claim 7 , further comprising shaping the shaft flange by press working. 9. The joint structure according to claim 7 , wherein the shaft flange is expanded so as to have a shape substantially along a shape of an opening peripheral edge portion of the hole on the front wall side. Method. The method for manufacturing a bumper structure according to any one of claims 7 to 9, wherein the shape of the closed section is made of an aluminum alloy extruded material. The tubular member is expanded by the electromagnetic forming so that the shaft portion is in close contact with the inner peripheral surface of the hole, and at the same time, the shaft portion protruding between the front and rear walls and the rear side of the rear wall is projected in the outer diameter direction. A method for manufacturing a bumper structure according to any one of claims 7 to 10 . The bumper structure according to any one of claims 7 to 10 , wherein both end portions of the bumper beam are crushed in the front-rear direction, and the holes are punched in the front and rear walls overlapped by the crushing process. Manufacturing method. The method for producing a bumper structure according to claim 12, wherein the hole is a burring hole, and is formed by burring from the front side after punching.

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