JP6084544B2 - Manufacturing method of frame member for automobile - Google Patents

Description

The present invention relates to a method for manufacturing an automobile frame member that hot three-dimensionally bends a metal hollow closed section member.

  A straight steel pipe is manufactured by welding welded flanges at both ends of a steel sheet bent into a closed cross section, and the steel pipe is bent while being heated with a coil through which a high-frequency current flows. An apparatus for manufacturing an A-pillar, a roof side rail, and a C-pillar of a continuous automobile is known from Patent Document 1 below.

WO2008 / 123506A1

  By the way, when a steel pipe having a closed cross section is bent by the three-dimensional bending apparatus described in Patent Document 1, a tensile load is applied to the outer part in the bending direction of the steel pipe, and a compressive load is applied to the inner part in the bending direction of the steel pipe. In addition, there was a problem in that the steel pipe buckled at the inner side in the bending direction where a compressive load was applied, causing wrinkles.

  The present invention has been made in view of the above-described circumstances, and prevents the inner closed portion of the hollow closed cross-section member from being wrinkled when hot three-dimensional bending is performed on the metal hollow closed cross-section member. With the goal.

In order to achieve the above object, according to the first aspect of the present invention, there is provided a method for manufacturing a frame member for an automobile, wherein a metal hollow closed cross-section member is hot three-dimensionally bent. member, an outer wall positioned in the curved outwardly, is configured in a triangular cross-section having a first inner wall and second inner wall positioned in the curved inward, during hot three-dimensional bending, section two of the hollow closed section member A tensile load is applied to the outer half of the outer wall and the second inner wall in the bending direction on the opposite side of the bending center of the hot three-dimensional bending process from the center of the second moment, and from the center of the sectional second moment. also the bending caused to act the first inner wall and compressive load to bend inward half of the second inner wall located on the center side, bending inward half portion of the first inner wall compressive load is applied and the second inner wall In Method of manufacturing an automotive frame member, wherein the hollow closed section bead groove cross-section recessed toward the inside cross section of the member is formed is proposed.

According to the second aspect of the present invention, in addition to the configuration of the first aspect, the hollow closed cross-section member is a roof side rail of an automobile, and a pair of the outer walls facing upward or in the vehicle width direction are provided on the outer wall. A method of manufacturing an automobile frame member is proposed, in which a groove portion having a U-shaped cross section having a side wall and a bottom wall is formed.

According to the invention described in claim 3, in addition to the configuration of claim 2, the first inner wall facing downward or the vehicle width direction outer side and the second inner wall facing the vehicle width direction inner side are continuous. on top, the form of the mounting surface of the bracket that supports the roof side outer panel covering the roof side rail, the manufacture of automotive frame member, characterized in that at least one of the bead was positioned adjacent the mounting surface A method is proposed.

According to the invention described in claim 4, in addition to the configuration of claim 3, a joint flange is provided at a joint portion between the outer wall and the second inner wall, and the roof side outer panel is provided on the upper surface of the joint flange. A first step portion that is bent downward in the vehicle width direction inner end and a second step portion that is bent downward in the vehicle width direction outer end of the roof panel, and an upper end of the first step portion is connected to the second step portion. The manufacturing method of the frame member for motor vehicles characterized by making it higher than the upper end of a step part is proposed.

According to the invention described in claim 5, in addition to the structure of any one of claims 2 to 4, the outer wall is located on the inner side in the vehicle width direction and has a first portion facing upward. A method for manufacturing an automobile frame member is proposed, comprising a second portion located outside in the vehicle width direction and facing upward or outward in the vehicle width direction.

According to a sixth aspect of the present invention, in addition to the configuration of the first aspect, the hollow closed cross-section member is a front pillar of an automobile, the outer wall facing the front or the vehicle width direction outside, and the rear or the vehicle. The vehicle includes a first inner wall facing outward in the width direction and a second inner wall facing inward in the vehicle width direction, and an outer end in the vehicle width direction of the windshield is bonded to a top portion where the outer wall and the second inner wall are connected. The manufacturing method of the frame member for motor vehicles characterized by providing the joining flange which is described above is proposed.

  The A-pillar upper 30 of the embodiment corresponds to the front pillar or the hollow closed section member of the present invention, and the roof side rail 33 of the embodiment corresponds to the hollow closed section member of the present invention. The flat portion 55 corresponds to the mounting surface of the present invention, and the lower wall 56c of the embodiment corresponds to the bracket of the present invention.

According to the configuration of claim 1, during hot three-dimensional bending of a metal hollow closed cross-section member, the side opposite to the center of bending of the hot three-dimensional bending than the center of the secondary moment of section of the hollow closed cross-section member A tensile load acts on the outer half of the outer wall and the second inner wall in the bending direction, and compression is applied to the inner half of the first inner wall and the second inner wall in the bending direction with respect to the center of the second moment of section. Since the load acts, wrinkles are likely to occur in the inner half of the first inner wall and the second inner wall in the bending direction, and the inner half of the first inner wall and the second inner wall in the bending direction are closed. Since the groove-shaped cross-section bead that is recessed toward the cross-section of the cross-sectional member is formed, out-of-plane deformation of the first inner wall and the second inner wall can be suppressed by the bead, and generation of wrinkles can be prevented.

  According to the second aspect of the present invention, the hollow closed cross-section member is a roof side rail of an automobile, and the outer wall facing the upper side of the roof side rail or the outside in the vehicle width direction has a U-shape having a pair of side walls and a bottom wall. Since the groove of the cross section is formed, even if a load is applied to the roof side rail when the car rolls over due to an accident, the rigidity of the roof side rail is enhanced by the groove of the U-shaped cross section, and the roof side rail is difficult to deform. Become.

  According to the configuration of claim 3, the roof side rail is arranged at the top where the first inner wall facing the lower side of the roof side rail or the outer side in the vehicle width direction and the second inner wall facing the inner side in the vehicle width direction of the roof side rail are continuous. Since the mounting surface of the bracket that supports the roof side outer panel that covers the surface is formed, wrinkles are likely to occur on the mounting surface during hot three-dimensional bending, but at least one of the beads is disposed adjacent to the mounting surface. The bead can suppress out-of-plane deformation of the mounting surface and prevent wrinkles.

  According to the fourth aspect of the present invention, the first flange is provided with a joint flange for joining the outer wall of the roof side rail and the second inner wall, and the inner end in the vehicle width direction of the roof side outer panel is bent downward on the upper surface of the joint flange. Since the stepped portion and the second stepped portion where the outer end of the roof panel in the vehicle width direction is bent downward are connected, the upper end of the first stepped portion is made higher than the upper end of the second stepped portion. When the part is viewed, the roof side outer panel and the joined part of the roof panel are difficult to see behind the first step part of the roof side outer panel, and the molding that covers the joined part can be eliminated.

  According to the fifth aspect of the present invention, the outer wall of the roof side rail is located on the inner side in the vehicle width direction and faces upward, and the outer wall of the roof side rail is located on the outer side in the vehicle width direction and faces upward or outward in the vehicle width direction. Since it consists of two parts, the cross-sectional area of a roof side rail can be expanded and bending rigidity can be improved.

  According to the configuration of claim 6, the hollow closed cross-section member is a front pillar of an automobile, an outer wall facing forward or in the vehicle width direction, a first inner wall facing rearward or in the vehicle width direction, and an inner side in the vehicle width direction. The direction of the line of sight of the occupant in the vehicle interior is substantially parallel to the first inner wall and the second inner wall, so that the occupant's field of view can be maximized without being blocked by the front pillar. it can. Moreover, since the joint flange to which the outer end in the vehicle width direction of the windshield is bonded is provided at the top where the outer wall and the second inner wall are connected, the joint flange is originally attached to the outer end in the vehicle width direction of the windshield that obstructs the sight of the occupant. By overlapping, it is possible to avoid a reduction in visual field due to the provision of the joint flange.

The perspective view of the body frame of the side part of a motor vehicle. FIG. 2 is an enlarged sectional view taken along line 2-2 in FIG. 1. FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. 1. Explanatory drawing of a three-dimensional hot bending apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In the present specification, the front-rear direction, the left-right direction (vehicle width direction), and the up-down direction are defined with reference to an occupant seated in the driver's seat.

  As shown in FIG. 1, the vehicle body frame on the side portion of the automobile includes a pair of left and right side sills 13 disposed in the front-rear direction on the outer side in the vehicle width direction. A pair of left and right A-pillars (front pillars) lowers 24 and 24 rise from the front ends of the left and right side sills 13 and 13, and a pair of left and right B pillars (center pillars) 25 and 25 rise from the middle in the front-rear direction of the left and right side sills 13 and 13. Rises, a pair of left and right C pillars (rear pillars) 26, 26 stand from the rear ends of the left and right side sills 13, 13, and a pair of left and right D pillars 27, 27 stand from the rear ends of the left and right rear side frames 14, 14. To do.

  A roof side rail 33 extends rearward from the rear end of the A pillar upper 30. The A-pillar upper 30 and the roof side rail 33 according to the present embodiment are integrally formed by bending one straight steel pipe 40 with a hot three-dimensional bending apparatus. As shown in FIG. 1 in an enlarged manner, the steel pipe 40 constituting the A pillar upper 30 and the roof side rail 33 has a closed cross section by bending a single steel sheet by roll forming and welding W1 at both ends of the flange. Composed.

  FIG. 4 shows a hot three-dimensional bending apparatus for bending and heat treating a steel pipe 40 having a closed cross section. The hot three-dimensional bending apparatus has a well-known structure, and is provided at the outlet of the steel pipe delivery apparatus 41 and the steel pipe delivery apparatus 41 that sends out the steel pipe 40 formed in a closed cross section by roll forming in the longitudinal direction thereof. The bending fulcrum member 42, the high-frequency heating coil 43 provided on the downstream side of the bending fulcrum member 42, the cooling device 44 provided on the downstream side of the high-frequency heating coil 43, and the downstream side of the cooling device 44. And a bending device 45 formed of a robot. The steel pipe 40 is a linear member having a constant cross section in the longitudinal direction, and a bending moment is applied by a bending device 45 in a state where the steel pipe 40 is heated by a high-frequency heating coil 43, so that the steel pipe 40 is positioned downstream of the bending fulcrum member 42. After being bent into a predetermined shape, quenching can be performed by quenching with cooling water ejected from the cooling device 44.

  FIG. 2 shows a cross section of the roof side rail 33. The roof side rail 33 obtained by bending the steel pipe 40 has a triangular cross section composed of an outer wall 51, a first inner wall 52, and a second inner wall 53. The joining flange 51a provided at the end of the outer wall 51 and the joining flange 53a provided at the end of the second inner wall 53 are overlapped and welded W1. The outer wall 51 faces upward or in the vehicle width direction, the first inner wall 52 faces downward or in the vehicle width direction, the second inner wall 53 faces inward in the vehicle width direction, and the joint flanges 51a and 53a are inward in the vehicle width direction. It extends to.

  A portion where the outer wall 51 and the first inner wall 52 are continuous is formed with a first flat portion 54 facing outward in the vehicle width direction, and a portion where the first inner wall 52 and the second inner wall 53 are continuous is formed with a second flat portion 55 facing downward. It is formed. A groove portion 51b having a U-shaped cross section recessed inward of the cross section is formed at the inner end of the outer wall 51 in the vehicle width direction. The first inner wall 52 is formed with two beads 52 a and 52 b having an arcuate cross-section recessed inside the cross section, and one of the beads 52 b is adjacent to the second flat portion 55. The second inner wall 53 is formed with a single bead 53b having an arcuate cross section that is recessed inside the cross section.

  The outer side in the vehicle width direction of the roof side rail 33 is covered with a roof side outer panel 56 having a U-shaped cross section having an upper wall 56a, a side wall 56b, and a lower wall 56c, and the inner end in the vehicle width direction of the upper wall 56a is the roof side. It is overlapped on the upper surfaces of the joining flanges 51a and 53a of the rail 33 and welded W2. And the front-end | tip of the 1st step part 56e which bent the vehicle width direction inner end of the upper wall 56a of the roof side outer panel 56 downward, and the front-end | tip of the 2nd step part 57a which bent the vehicle width direction outer end of the roof panel 57 downward And are welded W3 in the vicinity of the weld W2. The height of the upper end of the first step portion 56 e of the roof side outer panel 56 is higher than the height of the upper end of the second step portion 57 a of the roof panel 57. Further, the inner end in the vehicle width direction of the lower wall 56c of the roof side outer panel 56 is welded W4 to the second flat portion 55 of the roof side rail 33.

  A side airbag device 60 including an inflator 58 and a folded airbag 59 is provided on the inner surface in the vehicle width direction of the second inner wall 53 of the roof side rail 33, and the side airbag device 60 and the roof panel 57 are roofed. 61.

  FIG. 3 shows a cross section of the A pillar upper 30 integrally extending from the front end of the roof side rail 33 shown in FIG. 2 toward the front lower side, and the cross section of the roof side rail 33 and the cross section of the A pillar upper 30 are the same. . However, while the roof panel 57 is connected to the inside of the roof side rail 33 in the vehicle width direction, the windshield 63 is connected to the joint flanges 51a and 53a at the inner end in the vehicle width direction of the A pillar upper 30 via the adhesive 62. The outer end of the vehicle width direction is bonded.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  As is apparent from FIG. 2, when the steel pipe 40, which is the material of the roof side rail 33 (or A pillar upper 30), is bent by a hot three-dimensional bending apparatus, the roof side rail 33 is bent with respect to the bending center Q. The outer wall 51 is located on the radially outer side, and the first inner wall 52 and the second inner wall 53 are located on the radially inner side. Accordingly, a tensile load acts on the upper half of the outer wall 51 and the second inner wall 53 located on the opposite side of the bending center Q from the center P of the sectional secondary moment of the roof side rail 33, A compressive load acts on the lower half of the second inner wall 53 and the first inner wall 52 located on the bending center Q side with respect to the center P.

  In the portion where the tensile load is applied, the plate material of the roof side rail 33 is not easily stretched and deformed and wrinkles are not generated. However, in the portion where the compressive load is applied, the plate material of the roof side rail 33 is easily buckled. May occur. In particular, wrinkles are likely to occur in a portion where the amount of compressive deformation is large because it is close to the bending center Q, that is, a portion where the first inner wall 52 and the second inner wall 53 are connected. However, according to the present embodiment, the beads 52a, 52b, and 53b having arc-shaped cross sections are formed on the first inner wall 52 and the second inner wall 53 on which the compressive force acts when the roof side rail 33 is bent. The beads 52a, 52b, and 53b can increase the rigidity of the first inner wall 52 and the second inner wall 53, and can effectively prevent wrinkles during bending.

  Further, the second flat portion 55 where the lower wall 56c of the roof side outer panel 56 is connected to the roof side rail 33 is closest to the bending center Q, so that the amount of compressive deformation is maximized, but is adjacent to the second flat portion 55. Secondly, since the bead 52b of the first inner wall 52 is formed, the out-of-plane deformation of the second flat portion 55 can be suppressed and the generation of wrinkles can be prevented.

  Further, when a load is applied to the outer wall 51 of the roof side rail 33 due to an accident or the like, the groove 51b having a U-shaped cross section having a pair of side walls and a bottom wall is formed on the outer wall 51. The deformation of the roof side rail 33 can be suppressed by increasing the rigidity of the outer wall 51 by the pair of side walls extending in the direction of the movement. Furthermore, the outer wall 51 of the roof side rail 33 includes a first portion 51c located on the inner side in the vehicle width direction and facing upward, and a second portion 51d located on the outer side in the vehicle width direction and facing upward or outward in the vehicle width direction. Since it is formed, the outer wall 51 of the roof side rail 33 can be curved outward to increase the cross-sectional area, and the bending rigidity can be further increased.

  The vicinity of the first step portion 56e at the inner end in the vehicle width direction of the roof side outer panel 56 and the vicinity of the second step portion 57a at the outer end in the vehicle width direction of the roof panel 57 are overlapped and welded W3. Since the upper end of the first step portion 56e is made higher than the upper end of the second step portion 57a, when the roof portion is viewed from the outside of the automobile, it is hidden behind the first step portion 56e of the roof side outer panel 56. It becomes difficult to see the joint where the roof side outer panel 56 and the roof panel 57 are welded W3, and the molding for covering the joint can be eliminated to reduce the cost.

  As apparent from FIG. 3, since the A pillar upper 30 also has the same cross-sectional shape as the roof side rail 33, the same effect as the roof side rail 33 can be achieved. The unique effect of the pillar upper 30 can be achieved.

  That is, the A-pillar upper 30 includes an outer wall 51 that faces the front or the vehicle width direction outside, a first inner wall 52 that faces the rear or the vehicle width direction, and a second inner wall 53 that faces the vehicle width direction inside. The direction of the line of sight of the occupant is substantially parallel to the first inner wall 52 and the second inner wall 53, so that the occupant's field of view can be maximized without being blocked by the A-pillar upper 30. Moreover, since the joint flanges 51 a and 53 a to which the outer end in the vehicle width direction of the windshield 63 is bonded are provided at the top where the outer wall 51 and the second inner wall 53 are connected, the front of the occupant's line of sight is originally blocked by the adhesive 62. By overlapping the joining flanges 51a and 53a on the outer end of the glass 63 in the vehicle width direction, it is possible to avoid a reduction in visual field due to the provision of the joining flanges 51a and 53a.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, the hollow closed cross-section member of the present invention is not limited to the roof side rail 33 or the A pillar upper 30 of the embodiment.

  In addition, the cross-sectional shape of the bead of the present invention is not necessarily an arc shape, and an arbitrary groove shape such as a triangular shape or a trapezoidal shape can be adopted. However, an arc-shaped bead easily disperses a load and is processed. Is excellent in that it is easy.

30 A pillar upper (front pillar, hollow closed section member)
33 Roof side rail (hollow closed section member)
51 outer wall 51a joining flange 51b groove 51c first part 51d second part 52 first inner wall 52a bead 52b bead 53 second inner wall 53a joining flange 53b bead 55 second flat part (mounting surface)
56 Roof side outer panel 56c Lower wall (bracket)
56e First step portion 57 Roof panel 57a Second step portion 63 Windshield
Center of P- section secondary moment
Q hot three-dimensional bending of the bending center

Claims (6)

A method for manufacturing an automobile frame member for hot three-dimensional bending of a metal hollow closed cross-section member (33, 30),
The hollow closed cross-section members (33, 30) are configured to have a triangular cross section having an outer wall (51) positioned on the outer side in the bending direction, and a first inner wall (52) and a second inner wall (53) positioned on the inner side in the bending direction. In the hot three-dimensional bending process, the hollow closed cross-section member (33, 30) is positioned on the opposite side of the bending center (Q) of the hot three-dimensional bending process from the center (P) of the secondary moment of section. A tensile load is applied to the outer half of the outer wall (51) and the second inner wall (53) in the bending direction, and the bending moment (Q) is located closer to the bending center (Q) than the center (P) of the second moment of section. by applying a compressive load to bend inward half of the first inner wall (52) and said second inner wall (53), the bending direction of the compressive load is applied first internal wall (52) and said second inner wall (53) the hollow closed section member on the inner half ( Bead (52a of the grooved cross-section recessed toward the inside cross section of the 3, 30), 52 b, a manufacturing method of an automotive frame member characterized by 53b) are formed. The hollow closed cross-section member (33) is a roof side rail (33) of an automobile, and a groove portion having a U-shaped cross section having a pair of side walls and a bottom wall on the outer wall (51) facing upward or in the vehicle width direction. (51b) is formed , The manufacturing method of the frame member for motor vehicles of Claim 1 characterized by the above-mentioned. A roof side outer panel covering the roof side rail (33) at the top where the first inner wall (52) facing downward or the vehicle width direction outside and the second inner wall (53) facing the vehicle width direction inner side are continuous. 56), a mounting surface (55) of the bracket (56c) for supporting is formed, and at least one of the beads (52a, 52b, 53b) is disposed adjacent to the mounting surface (55). The manufacturing method of the frame member for motor vehicles of Claim 2. A joint flange (51a, 53a) is provided at a joint between the outer wall (51) and the second inner wall (53), and a vehicle width of the roof side outer panel (56) is provided on the upper surface of the joint flange (51a, 53a). A first step portion (56e) bent at the inner end in the direction and a second step portion (57a) bent at the outer end in the vehicle width direction of the roof panel (57); The method for manufacturing a vehicle frame member according to claim 3, wherein the upper end of (56e) is made higher than the upper end of the second step portion (57a). The outer wall (51) includes a first portion (51c) positioned on the inner side in the vehicle width direction and facing upward, and a second portion (51d) positioned on the outer side in the vehicle width direction and facing upward or on the outer side in the vehicle width direction. The manufacturing method of the frame member for motor vehicles according to any one of claims 2 to 4 characterized by becoming. The hollow closed cross-section member (30) is a front pillar (30) of an automobile, the outer wall (51) facing the front or the vehicle width direction outside, and the first inner wall (52) facing the rear or the vehicle width direction outside. And the second inner wall (53) facing inward in the vehicle width direction, and the outer end in the vehicle width direction of the windshield (63) is at the top where the outer wall (51) and the second inner wall (53) are connected. The method for manufacturing a frame member for an automobile according to claim 1, wherein bonding flanges (51 a, 53 a) to be bonded are provided.

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