JP4459220B2 - Manufacturing method of tubular member with flange - Google Patents

Description

The present invention relates to a method for manufacturing a flanged tubular member having a mounting flange at the shaft end of a shaft portion made of an aluminum alloy material.

  For example, bumper reinforcement is provided as a reinforcing member inside a bumper installed at the front end (front) and rear end (rear) of an automobile body such as a passenger car or a truck. The bumper reinforcement is a hollow member having a front wall and a rear wall that are generally perpendicular to the load direction, and a lateral wall that connects them, and is supported by a pair of bumper stays from the rear side. It is fixed to the tip of the side member (front or rear).

  Aluminum bumper stays can be broadly divided into vertical and lateral collapse types. As shown in FIG. 11A, the vertical crushing type bumper stay has plate-like mounting flanges 2 and 3 (bumper reinforcements 4 and side members 5 at the front and rear ends of the hollow extruded shape member constituting the shaft portion 1. The direction of the extrusion axis is directed to the longitudinal direction of the vehicle body (substantially perpendicular to the longitudinal direction of the bumper reinforcement 4). As shown in FIG. 11 (b), the lateral crush type bumper stay is composed of an extruded shape member 6 in which mounting flanges 7 and 8 are integrally formed at the front and rear ends, and the extrusion axis direction is the vehicle body vertical direction (bumper reinforcement). (Vertical to the longitudinal direction of 4). Examples of the lateral crush type bumper stay include the following Patent Documents 1 to 3.

JP-A-8-91154 JP 2000-318552 A JP 2001-294106 A

  The vertical crush type bumper stay is generally high in manufacturing cost because three parts are integrated by welding. Further, as shown in FIG. 11 (a), the end attachment portion of the bumper reinforcement is rearward with respect to the vehicle width direction. In the case of tilting to the side, there are problems such as a decrease in yield due to oblique cutting of the shaft extruded section, an increase in cutting cost, and welding cost. In addition, the lateral compression type bumper stay is inexpensive to manufacture and has the advantage that it can be easily accommodated even if the bumper reinforcement end mounting location is inclined or curved with respect to the vehicle width direction. Thus, there is a problem in that the weight-specific energy absorption amount is small, and an advantageous lightening effect cannot be obtained.

  On the other hand, the specifications and drawings of Japanese Patent Application Nos. 2002-240366, 2002-357820, and 2002-357721 are made of an aluminum alloy extruded material (pipe material) as shown in FIG. Bumper stays in which mounting flanges 12 and 13 are formed by electromagnetic forming at both ends are described.

  In this bumper stay, as shown in FIG. 12, an extruded aluminum material is cut to a predetermined length to form a material tube 14, and the periphery of the material tube 14 is surrounded by an electromagnetic forming die 15 (from a plurality of divided dies). The end portion of the material tube 14 protrudes from the end surfaces (molding surfaces) 16 and 17 of the mold 15 and is inserted into the electromagnetic forming coil 18 inserted into the material tube 14 at a high voltage. Manufactured by instantaneously charging (discharging) stored electrical energy (electric charge). Electromagnetic forming means that, by applying electric energy, the electromagnetic forming coil 18 forms a strong magnetic field for a very short time, and the workpiece (workpiece) placed in this magnetic field repels the magnetic field (the left hand of Fleming). In this example, the material tube 14 is strongly expanded by utilizing a plastic deformation at a high speed by receiving a strong expansion force or contraction force by a Lorentz force according to the law of The outer diameter direction (radial direction) is increased by force, the material tube 14 is pressed against the inner surface of the through hole 19 inside the end surfaces 16 and 17, and the material tube 14 is expanded outside the end surfaces 16 and 17. It strikes against the end faces 16,17.

Since electromagnetic forming is a high-speed deformation, it is possible to cope with a case where the machining shape is complicated, and there is an advantage that the shape accuracy is good because a predetermined shape is obtained by pressing against the molding surface of the mold. Therefore, by making the end surfaces (molding surfaces) 16 and 17 of the mold 15 into appropriate shapes, not only the flange (flange 13) having a surface perpendicular to the axial direction but also the surface perpendicular to the axial direction. A flange having a shape corresponding to the shape of the mounting surface of the bumper reinforcement or the side member, such as an inclined flange (flange 12) or a flange having a curved surface, can be formed.
In addition, electromagnetic shaping | molding itself is a well-known technique, as described in the following patent documents 4-7 and nonpatent literature 1.

Japanese Patent Laid-Open No. 58-4601 JP-A-6-31226 JP-A-7-116751 JP 2002-86228 A Mechanical Technology Research Institute Report No. 150 “Research on Plastic Working Using Electromagnetic Force” (published by Mechanical Technology Research Institute in March 1990)

  By the way, the conventional crush-type bumper stay consisting of three parts has the above-mentioned problems and the welded point is the intersection of the shaft part and the flange where the load is most applied at the time of collision. In this case, the material properties may deteriorate, and this may lead to an unexpected decrease in energy absorption properties.

On the other hand, if the both ends of the tubular aluminum alloy extruded material are expanded in diameter by electromagnetic forming or the like and the flange is integrally formed with the shaft portion, this problem is solved. However, in this case, the closer to the outer periphery of the flange, the greater the amount of tensile deformation in the circumferential direction, resulting in a decrease in wall thickness. This becomes more problematic as the outer diameter of the flange becomes larger than the diameter of the shaft portion of the aluminum alloy extruded material.
The problem of occurrence of cracks becomes particularly serious in the case of an aluminum alloy extruded material having a fiber structure. This is because the fiber structure has mostly grain boundaries parallel to the extrusion direction, and the diameter-enlarged forming force introduced by electromagnetic forming or the like acts in a direction to break (tear) the grain boundaries. In addition, the fiber structure generally has a small elongation in the direction perpendicular to the extrusion direction. As is well known, aluminum alloy extruded material with fiber structure is excellent in axial crushing performance, so it has great utility value as a bumper stay, but the moldability in the diameter expansion direction is inferior to that of equiaxed crystals, and the tube When a flange is formed at the end, cracks are particularly likely to occur, and it is extremely difficult to form a flange large enough to be connected to the bumper reinforcement and the side member.

  FIG. 13 shows a state in which the thickness of the flange 12 becomes thinner toward the outer peripheral side after the flange is formed by electromagnetic forming (the flange 13 is also the same). Because the direction has changed, even if the end surface (molding surface) 16 of the mold 15 is a flat surface, the front surface 12a of the flange 12 is not a flat surface. As a result, as shown in FIG. For example, when the flange 12 is fixed to the rear wall 4 a of the bumper reinforcement 4, a gap 19 is formed between the flange 12 and the rear wall 4 a of the bumper reinforcement 4. If there is this gap 19, the flange 12 is distorted when it is fixed by bolts, nuts or rivets, and when it is fixed by welding, the flange 12 is fixed in a state of being lifted from the rear wall 4a of the bumper reinforcement 7 ( The same applies to the case where the flange 13 is fixed to the tip of the side member). This problem also becomes more problematic as the outer diameter of the flange becomes larger than the diameter of the shaft portion of the aluminum alloy extruded material.

  The present invention has been made in view of the problems of the prior art, and the outer diameter of the shaft portion is not compared with the diameter of the shaft portion without causing the welding portion to be applied to the shaft portion and without excessively expanding the diameter. An object of the present invention is to obtain a flanged tubular member such as a bumper stay having a large flange.

The flanged tubular member disclosed in the present specification is as follows (1) to (3).
(1) A shaft member made of a tubular aluminum alloy material and a flange member joined to an end of the shaft member, and an end flange having a smaller area than that of the flange member is integrated with the end of the shaft member. The flange member is formed with a hole in which the shaft member is inserted and a cylindrical hole flange is formed at an edge of the hole, and the shaft member is inserted into the hole of the flange member, and an end portion thereof A flanged tubular member in which a flange is closely polymerized with the flange member . The end flange of the shaft member can be formed by electromagnetic forming or the like, and the shaft member and the flange member can be joined using welding or mechanical joining means (rivets or the like). As the tubular aluminum alloy material, it is possible to use an extruded material formed by winding a plate material into a tubular shape.

  In the flanged tubular member, it is desirable that the outer peripheral surface of the shaft member is in close contact with the inner surface of the hole flange of the flange member. Thereby, the flange member joined to the shaft member becomes more stable, and the alignment of both at the time of manufacture becomes easy. Further, it is desirable that an overhang portion is formed on the shaft member, and a hole flange of the flange member is sandwiched between the end flange of the shaft member and the overhang portion. In this case, the shaft member and the flange member are joined (a kind of caulking) without using welding or mechanical joining means, but welding or mechanical joining means can also be used together. If electromagnetic forming is used, this flanged tubular member can be easily manufactured by a single forming. Specifically, a plate-like flange member in which a cylindrical hole flange is formed at the hole and the edge of the hole, and a shaft member made of a tubular aluminum alloy material are prepared, and the shaft member is inserted into the hole of the flange member. The tip of the shaft member protrudes from the hole in the axial direction by a predetermined distance, and the shaft member is expanded in diameter by electromagnetic forming, whereby the shaft member is brought into close contact with the inner peripheral surface of the hole flange and at the same time The portion protruding from the hole is expanded and closely polymerized with the flange member, and at least the vicinity of the hole flange of the shaft member is projected in the outer diameter direction on the inner side in the axial direction from the hole flange. Thereby, the flange member is joined to the end of the shaft member.

(2) A shaft member made of a tubular aluminum alloy material and a flange member joined to an end portion of the shaft member, and an end flange having a smaller area than the flange member is integrated with the end portion of the shaft member. The flange member is formed with a hole into which the shaft member is inserted, the shaft member is inserted into the hole of the flange member, and an end flange thereof is closely overlapped with the flange member. Tubular member with flange . The end flange of the shaft member can be formed by electromagnetic forming or the like, and the shaft member and the flange member can be joined by welding or mechanical joining means.

  In the flanged tubular member, it is desirable that the outer peripheral surface of the shaft member is in close contact with the inner edge of the hole of the flange member. Thereby, the flange member joined to the shaft member becomes more stable, and the alignment of both at the time of manufacture becomes easy. Furthermore, it is desirable that an overhang portion is formed in the shaft member, and the peripheral edge of the hole of the flange member is sandwiched between the end flange of the shaft member and the overhang portion. In this case, the shaft member and the flange member are joined (a kind of caulking) without using welding or mechanical joining means, but welding or mechanical joining means can also be used together. If electromagnetic forming is used, this flanged tubular member can be easily manufactured by a single forming. That is, a plate-like flange member in which a hole is formed and a shaft member made of a tubular aluminum alloy material are prepared, the shaft member is fitted into the hole of the flange member, and the tip thereof is axially outward from the hole. The shaft member is protruded by a predetermined distance, and the diameter of the shaft member is increased by electromagnetic forming. Thereby, the shaft member is brought into close contact with the inner edge of the hole, and at the same time, the portion that protrudes from the hole of the shaft member is expanded. The flange member is closely polymerized, and at least the vicinity of the flange member of the shaft member is projected in the outer diameter direction on the inner side in the axial direction from the flange member. Thereby, the flange member is joined to the end of the shaft member.

(3) A shaft member made of a tubular aluminum alloy material and a flange member made of an aluminum alloy material joined to an end portion of the shaft member, and an annular projecting portion is formed in the vicinity of the end portion of the shaft member, A flanged tubular member in which a hole is formed in the flange member, the entire periphery of the edge is curled toward the shaft member side, and the tip is fitted into the protruding portion of the shaft member from the inside . This is a flanged tubular member according to the present invention. In this case, the shaft member and the flange member are joined (a kind of caulking) without using welding or mechanical joining means.
If electromagnetic forming is used, this flanged tubular member can be easily manufactured by a single forming. That is, a shaft member made of a tubular aluminum alloy material and a plate-like flange member made of an aluminum alloy in which a hole is formed are prepared, and the shaft member is positioned so that the hole is located at substantially the center of the cross section of the shaft member. The flange member is positioned at the end of the flange member, and the peripheral portion of the hole of the flange member is expanded by electromagnetic forming, and the vicinity of the end portion of the shaft member is annularly projected to the outer diameter side to form the flange member. The diameter-expanded portion is brought into close contact with the inner peripheral surface of the shaft member, and at the same time, the curled tip is fitted into the annularly projecting portion of the shaft member. Thereby, the flange member is joined to the end of the shaft member.

According to the present invention, there is provided a tubular member with a flange such as a bumper stay having a flange whose outer diameter is larger than the diameter of the shaft portion without causing the welding portion to be applied to the shaft portion and without excessively expanding the diameter. Obtainable. Furthermore, the flanged tubular member can be manufactured by joining the shaft member and the flange member by a kind of caulking by one electromagnetic forming without using welding or mechanical joining means as required.
In addition, since it is not necessary to perform excessive diameter expansion, an aluminum alloy extruded material having a fiber structure can be used as the shaft member. If this is used as, for example, a bumper stay, excellent crushing characteristics can be obtained.

Hereinafter, a flanged tubular member and a manufacturing method thereof according to the present invention (including a reference example) will be described with reference to FIG. 1 to FIG. 10 (FIGS. 1 to 8 are reference examples), taking a bumper stay as an example.
The bumper stay shown in FIG. 1 includes a shaft member 21 made of a tubular aluminum alloy extruded material, and flange members 22 joined to both ends of the shaft member 21. An end flange 23 having a smaller outer diameter than the flange member 22 is integrally formed at both ends of the shaft member 21, and the vicinity of the end in the axial direction is the small diameter portion 24, and the diameter is the smallest. A large-diameter portion 25 is projected over the outer diameter side. The flange member 22 is formed with a hole 26 into which the shaft member 21 is fitted and inserted at the center, and a cylindrical hole flange 27 at the edge of the hole 26. The shaft member 21 is inserted into the hole 26 of the flange member 22, and the end flange 23 is tightly overlapped with the outer surface of the flange member 22, while the protruding end 25 a of the large-diameter portion 25 is the end of the hole flange 27. As a result, the hole flange 27 is sandwiched between the end flange 23 and the large diameter portion 25. The outer peripheral surface of the small diameter portion 26 is in close contact with the inner peripheral surface of the hole flange 27.
Further, a stepped portion 28 substantially corresponding to the thickness of the end flange 23 is formed in the flange member 22 so that the end flange 23 just fits into a lowered portion on the inner peripheral side. Accordingly, the portion of the outer surface of the end flange 23 of the shaft member 21 and the outer surface of the flange member 22 that is not overlapped with the end flange 23 is substantially flush (same height).

The bumper stay manufacturing method (electromagnetic forming method) will be described with reference to FIGS.
The flange member 22 has the same shape as that shown in FIG. 1, and at the same time a pilot hole is formed in the center of a circular blank (plate material), a stepped portion 28 is formed in an annular shape, and then the pilot hole is subjected to burring. The cylindrical hole flange 27 can be manufactured by molding. The tube material 31 used for electromagnetic forming is made of an aluminum alloy extruded material having an outer diameter substantially the same as or slightly smaller than the inner diameter of the hole flange 27.
A mold 32 used for electromagnetic forming is composed of a plurality of vertically divided molds, and a through hole 33 is formed at the center when closed as shown in FIGS. The through hole 33 has a small diameter in the vicinity of both ends in the axial direction of the mold 32 within the range of the length of the hole flange 27 (small diameter portion 33a). The inner diameter of the small diameter portion 33a is such that the hole flange 27 fits in the inside. The outer diameter of the hole flange 27 is almost the same as that of the hole flange 27, and the diameter is larger than that of the small-diameter portion 33a (large-diameter portion 33b). Further, a stepped portion 34 a is formed on both end surfaces 34 of the mold 32, and the flange member 22 is just fitted into the end surface 34.

As shown in FIG. 2, the flange member 22 is set on both end surfaces 34 of the mold 32 so that the hole flange 27 faces the inner side in the axial direction, and the tube material 31 is inserted inside the hole flange 27. At this time, both end portions of the tube material 31 are projected from the flange member 22 by a predetermined distance. As shown in FIG. 1, the protrusion distance is adjusted so that the outer periphery of the end flange 23 that is electromagnetically formed is located on the inner periphery side of the step portion 28 of the flange member 27 (the protrusion distance is such a length). The tube material 31 is cut so that
Subsequently, when the electromagnetic forming current-carrying coil body 35 is inserted into the tube material 31 and electric energy stored and charged at a high voltage is applied to an impact current generator (not shown), a magnetic repulsive force is generated in the tube material 31. The pipe material 31 is instantaneously expanded in diameter, the end protruding from the flange member 22 is greatly expanded to hit the flange member 22, and the inner surface of the hole flange 27 is located at a position corresponding to the small diameter portion 33 a of the through hole 33. The large diameter portion 33b of the through hole 33 strikes the inner surface of the through hole 33. The electromagnetic forming energizing coil body 35 is formed by embedding a forming coil in an electrical insulator.

Thereby, the bumper stay shown in FIG. 1 is formed. After molding, the mold 32 is divided and the bumper stay is taken out.
In this bumper stay, as the diameter of the pipe material 31 is increased, the molded shaft member 21 (its small diameter portion 24) is pressed against the hole flange 27, and at the same time, the shaft member 21 (its end flange 23 and large diameter portion 25) is pressed. As a result, the hole flange 27 of the flange member 22 is sandwiched in the axial direction, so that the flange member 22 is firmly joined to both ends of the shaft member 21. Due to the presence of the hole flange 27, the contact area with the shaft member 21 is large, which also contributes to the improvement of the bonding strength. The flange member 22 has a sufficient outer diameter as a bumper stay, and on the other hand, it is not necessary to enlarge the outer diameter of the end flange 23 of the shaft member 21 so as to prevent the occurrence of cracks during electromagnetic forming. It is also possible to use an aluminum alloy extruded material having a fiber structure.

In the above example, the hole 26 of the flange member 22 has a circular shape, but it has an elliptical shape or an asymmetrical shape (for example, most of the edge of the hole is circular but partly recessed). A hole or a hole in which most of the edge of the hole is circular but partly straight). Such a cross-sectional shape has a function of preventing the shaft member 21 and the flange member 22 from rotating. In either case, the tube material can be of a circular cross section, and even if a circular cross section is used, the cross section of the portion pressed against the inner surface of the hole flange by electromagnetic forming is the shape of the hole. It is imitated.
The shaft member 21 (tube material 31) formed by this electromagnetic forming is made of an aluminum alloy extruded material having high electrical conductivity and a strong magnetic repulsive force. However, since the flange member 22 is not substantially deformed, aluminum is used. An alloy plate or a steel plate may be used. In terms of ease of burring, steel plates are preferred. When a steel plate is used as the flange member 22, in order to prevent galvanic corrosion due to contact with the shaft member 21, which is an aluminum alloy, at least the side in contact with the shaft member 21 is subjected to surface treatment for preventing erosion, such as aluminum plating. It is desirable to do.
Further, since the steel plate has high strength, low electrical conductivity, and little expansion force due to electromagnetic forming is applied, the steel plate flange member 22 has a strength sufficient to receive the expansion force when the pipe material 31 is expanded, and Electromagnetic molding can be performed without using the mold 32 as long as the positioning can be reliably performed so that the flange member 22 does not cause a positional shift or the like during the molding.

Subsequently, other bumper stays and flanged tubular members will be described below.
The bumper stay shown in FIG. 4 is substantially the same as the bumper stay shown in FIG. 1 except that the shaft member 21 and the flange member 22 are welded to join the shaft member 21 and the flange member 22 more firmly. is there. The weld location 36 is the outer peripheral edge of the end flange 23. Since the welded portion 36 is away from the shaft portion 37 (corresponding to the small diameter portion 24 and the large diameter portion 25 in FIG. 1) of the shaft member 21 in the outer diameter direction, the deterioration of the material properties due to the thermal effect does not reach the shaft portion 37. In addition, an unexpected decrease in energy absorption characteristics can be prevented.

The bumper stay shown in FIG. 5 differs from the bumper stay shown in FIG. 1 in that the large-diameter portion (bead-like protruding portion) 38 of the shaft member 21 is formed only in the vicinity of the hole flange 27. Are virtually identical. As in the bumper stay shown in FIG. 1, the small diameter portion 24 of the shaft portion 37 is pressed against the hole flange 27, and at the same time, the hole flange 27 is sandwiched between the end flange 23 and the large diameter portion 38. 22 is firmly joined to both ends of the shaft member 21.
In manufacturing the bumper stay shown in FIG. 5, an electromagnetic forming die 39 in which a tubular concave portion 39 a is formed at a location corresponding to the large diameter portion 38 may be used as indicated by a virtual line. The tube material freely expands (extends and deforms) in the recess 39a according to the expansion force applied during electromagnetic forming.

The bumper stay shown in FIG. 6 joins the flange member 22 only to one end portion of the shaft member 21, and uses the end flange 41 integral with the shaft member 21 as the mounting flange of the other end portion. is there. The bumper stay mounting flange generally requires a larger diameter on the side member side, which requires a separate flange member 22, but the bumper reinforcement mounting flange requires a smaller diameter. In some cases, this can be handled by an end flange 41 having an enlarged diameter at the end of the shaft member 21. In such a case, such a bumper stay can be used.
FIG. 6 shows a tube material 31 for molding the electromagnetic forming die 42 and the shaft member 21 with virtual lines.

The flanged tubular member shown in FIG. 7 is obtained by joining the flange member 22 to one end of the shaft member 51. This flange member 22 has the same shape as the flange member 22 in FIG. 1 and the like, but the shaft member 51 is formed integrally with an end flange 52 at one end, and there is no flange at the other end. Also, no overhanging portion or the like is formed.
In this flanged tubular member, the shaft member 51 is fitted into the hole 26 of the flange member 22, the end flange 52 closely overlaps with the outer surface of the flange member 22, and the outer peripheral surface of the shaft portion 53 is the hole flange 27. It is in close contact with the inner peripheral surface. The flange member 22 is formed with a stepped portion 28 substantially corresponding to the thickness of the end flange 52, the end flange 52 just fits into a lower portion on the inner peripheral side, and the outer peripheral edge of the end flange 52 is a welded portion. Thus, the shaft member 51 and the flange member 22 are joined. Further, a portion of the outer surface of the end flange 52 of the shaft member 51 and the outer surface of the flange member 22 that is not overlapped with the end flange 52 is substantially flush.
Also in this tubular member with flange, similarly to the bumper stay shown in FIG. 4, the welded portion 54 is away from the shaft portion 53 of the shaft member 51 in the outer diameter direction. There are advantages over

When this flanged tubular member is formed by electromagnetic forming, the flange member 22 is set on the end surface 57 of the electromagnetic forming die 56 (see the phantom line in FIG. 7) so that the hole flange 27 faces inward in the axial direction. Inside the flange 27, a tube material 58 (see a virtual line in FIG. 7) made of a tubular aluminum alloy extruded material is inserted. At this time, the end of the tube material 58 is projected from the flange member 22 by a predetermined distance. This protrusion distance is adjusted in the same manner as described above with reference to FIG. The end face 57 of the mold 56 has the same shape as the mold 32 shown in FIG. 3, and the through hole of the mold 56 has a large diameter in the vicinity of the end face 57 within the range of the length of the hole flange 27. Here, the outer diameter of the hole flange 27 is substantially the same so that the hole flange 27 fits in, and the outer diameter of the pipe material 58 is substantially the same as or slightly larger at other locations.
Subsequently, when the electromagnetic forming is performed in the same procedure as described above, the pipe material 58 is instantaneously expanded in diameter, the end portion protruding from the flange member 22 is greatly expanded and hits the flange member 22, and the die 56 The inside of the through hole is pressed against the inner peripheral surface of the hole flange 27 and the through hole.
Note that the end flange 52 can be formed using press forming (press tube expansion). Further, the shaft member 51 may be fitted into the flange member 22 after the end flange 52 is molded, or the end flange may be molded after the pipe material 58 is fitted into the flange member 22.

The bumper stay shown in FIG. 8 includes a shaft member 61 and flange members 62 joined to both ends thereof. An end flange 63 having an outer diameter smaller than that of the flange member 62 is integrally formed at both ends of the shaft member 61, and the vicinity of the axial end portion is a small diameter portion 64, and the diameter is the smallest. The large-diameter portion 65 projects to the outer diameter side. The flange member 62 is formed with a hole 66 into which the shaft member 61 is inserted in the center. The shaft member 61 is inserted into the hole 66 of the flange member 62, and the end flange 63 closely adheres to the outer surface of the flange member 62, while the end 65 a of the protruding large diameter portion 65 is located inside the flange member 62. As a result, the periphery of the hole 66 is sandwiched between the edge flange 63 and the large diameter portion 65. The outer peripheral surface of the small diameter portion 64 is in close contact with the inner edge of the hole 66. In short, the flange member 62 is different from the flange member 22 shown in FIG. 1 in that the hole flange 27 is not formed, and accordingly, the shape of the shaft member 61 is also different from that of the shaft member 21 shown in FIG. This is the only difference from the bumper stay shown in. Also in this case, the shaft member 61 and the flange member 62 can be welded as shown in FIG.
In FIG. 8, the electromagnetic forming die 67 and the tube material 68 are indicated by phantom lines.

The flanged tubular member shown in FIG. 9 relates to the present invention, and includes a shaft member 71 made of a tubular aluminum alloy extruded material and a flange member 72 joined to an end of the shaft member 71. An annular projecting portion 73 is formed near the end of the shaft member 71, a hole 74 is formed in the center portion of the flange member 72, and the entire periphery of the edge curls toward the shaft member 71. The tip of 75 is fitted into the projecting portion 73 from the inside and contacts the bottom thereof, and the outer peripheral surface of the curled portion 75 is in close contact with the inner peripheral surface of the end portion of the shaft member 71.

A manufacturing method (electromagnetic forming method) of the flanged tubular member will be described with reference to FIG.
The tube material 76 is made of a cylindrical aluminum alloy extruded material, and the flange material 77 is made of an aluminum alloy plate having a hole 78 (a hole smaller in diameter than the hole 74) in the center, and one surface of the flange material 77 is The hole 78 is in contact with the end face of the tube material 76, and is located at the center of the cross section of the tube material 76. Further, the vicinity of the edge of the hole 78 of the flange material 77 is inclined toward the tube material 76 side.
A mold used for electromagnetic forming is composed of a main mold 81 and a presser mold 82. The main mold 81 is composed of a plurality of vertically divided molds. When closed, as shown in FIG. 10, a through hole 83 is formed in the center, and an annular recess 83a is formed near the end of the through hole 83. Is formed. The inner diameter of the through hole 83 is substantially the same as the outer diameter of the tube material 76 except for the recess 83a. A through hole 84 is also formed in the center of the presser mold 82.

As shown in FIG. 10, the tube material 76 is inserted into the main mold 81 and positioned so that the end surface (upper end) thereof substantially coincides with the end surface 85 of the main mold 81. The flange material 77 is placed, the upper part is pressed by a pressing die 82, and then the electromagnetic forming energizing coil body 86 is inserted into the flange material 77 and the tube material 76, and electric energy is input. As a result, the peripheral edge of the hole 78 of the flange material 77 (the portion within the cross section of the tube material 76) and the tube material 76 are instantaneously expanded in diameter, and the vicinity of the edge of the hole 78 is greatly expanded. 9 is struck against the inner peripheral surface in the vicinity of the end of the material 76, while the vicinity of the end of the tube material 76 projects into the recess 83a to form the projecting portion 73. As a result, as shown in FIG. A curled portion 75 is formed at the edge of 74, and the outer periphery of the curled portion 75 is in close contact with the inner peripheral surface of the end portion of the shaft member 71, and at the same time, the curled tip is fitted into the protruding portion 73 of the shaft member 71 from the inside. . Thereby, the shaft member 71 and the flange member 72 are joined.
In this flanged tubular member, neither the shaft member 71 nor the flange member 72 needs to be enlarged so much that it can prevent cracking during electromagnetic forming, and the shaft member 71 has a fiber structure. The use of an aluminum alloy extruded material is also possible.

  The present invention has been specifically described above mainly using a bumper stay as an example. However, the present invention is a flange member attached to another member, such as a tubular member with another flange, for example, a reinforcement for an instrument panel for a vehicle, in the same form. It can be widely applied to the attached tubular member. Further, whether the flange member is joined to both ends of the shaft member or the flange member is joined to one end portion can be arbitrarily selected according to the usage mode of the flanged tubular member. Further, in the above example, the shaft member and the flange member are joined such that the shaft center line of the shaft portion of the flanged tubular member and the flange are perpendicular to each other. However, as in the bumper stay shown in FIG. Those in which the axial center line of the portion and the flange are inclined, those in which the flange is curved, or combinations thereof are also included in the present invention and can be manufactured by the same method as described above. .

It is sectional drawing of a bumper stay (reference example) . It is sectional drawing explaining the method to manufacture the bumper stay of FIG. 1 by electromagnetic forming. It is sectional drawing of the metal mold | die for electromagnetic forming used for the method. It is sectional drawing of another bumper stay (reference example) . Furthermore, it is sectional drawing of another bumper stay (reference example) . Furthermore, it is sectional drawing of another bumper stay (reference example) . It is sectional drawing of a tubular member with a flange (reference example) . Furthermore, it is sectional drawing of another bumper stay (reference example) . It is a cross-sectional view of the flanged tubular member about the present invention. It is sectional drawing explaining the method to manufacture the tubular member with a flange of FIG. 9 by electromagnetic forming. It is a top view which shows a bumper stay of various types, and its attachment state. It is sectional drawing explaining the method to manufacture the bumper stay of FIG.11 (c) by electromagnetic forming. It is an expanded sectional view of the flange part of the bumper stay. It is sectional drawing explaining the attachment state to the bumper reinforcement of the bumper stay.

Explanation of symbols

21, 51, 61, 71 Shaft member 22, 62, 72 Flange member 23, 41, 63 End flange 25, 38, 65 Large diameter portion (overhang portion)
26, 66, 74 Hole 27 Hole flange 28 Step part 31, 58, 68, 76 Pipe material 32, 39, 42, 56, 67, 81, 82 Electromagnetic forming die 35, 86 Electromagnetic forming coil body 36, 54 Welding point 73 Overhang 75 Curl 77 Flange material 78 Hole

Claims (3)

A plate-like flange member made of an aluminum alloy in which a hole is formed at the end of a shaft member made of a tubular aluminum alloy material is positioned so that the hole is located at substantially the center of the cross section of the shaft member, and electromagnetic forming The diameter of the peripheral edge of the hole of the flange member is increased by the above, and the vicinity of the end of the shaft member is annularly projected to the outer diameter side, and the diameter-enlarged portion of the flange member is the inner peripheral surface of the shaft member A method of manufacturing a flanged tubular member, wherein the flange member is joined to an end portion of the shaft member by fitting the curled tip into an annular projecting portion of the shaft member. The manufacturing method of the flanged tubular member according to claim 1 , wherein a peripheral portion of the hole of the flange member is inclined in advance toward the shaft member. When closed, it consists of a plurality of vertically divided molds, a main mold in which a through hole is formed at the center is closed, the shaft member is inserted into the through hole, and the end surface is the end surface of the main mold positioned so as to substantially coincide, placing the flange member to the end face of the main die, according to claim 1 in which the top supported by the support die and and performs enlarged by electromagnetic forming in this state Or the manufacturing method of the tubular member with a flange described in 2 .

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