JP2008195298A - Body parts and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate-shaped vehicle body part that is lightweight but has high bending rigidity.
SOLUTION: Since a large number of small holes h are drilled in a panel 19 obtained by drawing a blank into a predetermined shape, the panel 19 is a solid panel having the same material and the same bending rigidity while having a high bending rigidity. It is lighter than that. The panel 19 having a large number of small holes h has a reduced tensile strength, but the outer periphery of the panel 19 is welded to the inner periphery of the frame members 13, 14, 16 to compensate for the lack of tensile strength and light weight. A highly rigid body part can be obtained. Further, if a large number of small holes h perforated in the panel 19 are covered with a sheet 20 with an adhesive and waterproofed, water leakage through the small holes h can be reliably prevented. Furthermore, if the panel 19 is disposed in a portion that is crushed at the time of a vehicle collision, an arbitrary shock absorbing performance can be exhibited by adjusting the diameter, number, arrangement interval, aperture ratio, and the like of the small holes h.
[Selection] Figure 2

Description

  The present invention relates to a plate-like vehicle body part that achieves both improvement in bending rigidity and weight reduction, and a method for manufacturing the vehicle body part.

A thin plate used for automobile structural materials is composed of a central layer in which a large number of through-holes are formed and two surface layers laminated on both sides thereof, and the area ratio of through-holes in the central layer is 20% to Patent Document 1 listed below discloses that the tension rigidity is increased by setting the average area of the through holes to 20 mm ² or less.
JP-A-4-89235

  However, since the thin plate is composed of a central layer in which a large number of through holes are formed and two surface layers laminated on both sides of the thin plate, the structure is complicated and the manufacturing cost is low. Since the position of the through hole is not visible from the outside, the position of the through hole may not be constant when the thin plate is finished into a product shape.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a plate-like vehicle body part that is lightweight and has high bending rigidity, and a method for manufacturing the same.

  In order to achieve the above object, according to the first aspect of the present invention, there is proposed a vehicle body part characterized in that a large number of small holes are perforated in at least a portion excluding the outer peripheral portion of the panel.

  According to the invention described in claim 2, in addition to the structure of claim 1, a vehicle body part is proposed in which a large number of small holes perforated in the panel are covered with a sheet with an adhesive. .

  According to the invention described in claim 3, in addition to the structure of claim 1, a vehicle body part is proposed in which the panel is arranged in a portion to be crushed at the time of a collision.

  According to the invention described in claim 4, in addition to the structure of claim 1, there is proposed a vehicle body part characterized in that the small hole of the panel is formed except for a portion requiring strength. The

  According to the invention described in claim 5, a blank process for punching a blank having a predetermined shape from a plate material, a drawing process for drawing the blank into a predetermined shape, and a large number of small holes in the panel subjected to the drawing process. A method of manufacturing a vehicle body part is proposed, which includes a piercing step for perforating, a trim step for cutting off unnecessary portions of the outer periphery of the pierced panel, and a fixing step for fixing the trimmed panel to the vehicle body. .

  According to the invention described in claim 6, a blank step of punching a blank of a predetermined shape from a plate material, a piercing step of punching a large number of small holes in the blank, and a pierced blank being squeezed into a predetermined shape Proposed is a method of manufacturing a vehicle body part, comprising: a drawing process for machining; a trimming process for cutting off unnecessary portions on the outer periphery of the drawn panel; and a fixing process for fixing the trimmed panel to the vehicle body. .

  According to the configuration of the first aspect, since a large number of small holes are perforated in a portion excluding at least the outer peripheral portion of the panel, the panel is a solid panel having the same material and the same bending rigidity while having a high bending rigidity. The weight can be reduced compared to the above. A panel with a large number of small holes drilled has a reduced tensile strength, but since there are no small holes drilled in the outer periphery of the panel, the lack of tensile strength is compensated to obtain a lightweight and highly rigid body part. be able to.

  According to the configuration of claim 2, since a large number of small holes perforated in the panel are covered with the sheet with the adhesive, water leakage through the small holes can be prevented and rust on the inner surface of the small holes can be prevented. it can.

  Further, according to the configuration of the third aspect, since the panel in which a large number of small holes are formed is disposed in the portion to be crushed at the time of collision, the diameter, number, arrangement interval, aperture ratio, etc. of the small holes can be adjusted arbitrarily. The shock absorbing performance can be exhibited.

  According to the fourth aspect of the present invention, since the small holes are formed except for the portion that requires the strength of the panel, it is possible to minimize the decrease in the strength of the panel due to the small holes.

  Further, according to the configuration of claim 5, since the blank punched out from the plate material into a predetermined shape is drawn into a predetermined shape, and a large number of small holes are drilled therein, the unnecessary portion on the outer periphery is cut off. While having high bending rigidity, the weight can be reduced compared to a solid panel made of the same material and having the same bending rigidity.

  Further, according to the structure of the sixth aspect, since a large number of small holes are punched in a blank punched out from a plate material into a predetermined shape, and the outer peripheral unnecessary portion is cut out after being drawn into a predetermined shape, the panel Compared to a solid panel made of the same material and having the same bending rigidity, it can be reduced in weight while having a high bending rigidity.

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

  1 to 9 show a first embodiment of the present invention. FIG. 1 is a perspective view of a vehicle body frame of an automobile, FIG. 2 is a two-way enlarged view of FIG. 1, and FIG. Fig. 4 is an enlarged sectional view taken along line 3-3, Fig. 4 is an explanatory diagram of the manufacturing process of the panel, and Fig. 5 is a diagram for explaining the influence of the panel thickness and the aperture ratio of the small holes on the panel weight, tensile rigidity and bending rigidity. FIG. 6 is a graph showing the characteristics of tensile rigidity and bending rigidity with respect to the weight of the panel having different plate thicknesses and aperture ratios of the small holes, FIG. 7 is an enlarged view in the 7 direction of FIG. 1, and FIG. An arrow view and FIG. 9 are figures which show the back surface of a bonnet food | hood.

  As shown in FIG. 1, the vehicle body frame includes left and right front side frames 11 and 11, a dashboard 12, left and right side sills 13 and 13, a middle cross member 14, a center cross member 15, a center tunnel 16, and a rear floor panel 17. The left and right rear side frames (not shown), rear cross members (not shown), and the like.

  Four openings 18 partitioned in a “field” shape by left and right side sills 13 and 13 and a center tunnel 16 extending in the longitudinal direction of the vehicle body, a dashboard 12, a middle cross member 14 and a center cross member 15 extending in the vehicle width direction. In addition, four panels 19 constituting the front floor, which is the floor on the lower surface of the passenger compartment, are mounted. Further, three panels 19 are mounted in three openings 20 formed in the rear floor panel 17 connected to the rear of the front floor.

  Since these seven panels 19 have substantially the same structure with a slightly different planar shape, the manufacturing process of the one panel 19 will be described below.

  In a first blank process shown in FIG. 4A, a blank 19 ′ having a predetermined shape is cut from a strip-shaped steel plate by a blank mold, and in the subsequent draw process shown in FIG. 4B, the blank 19 is cut by a draw mold. ′ Is drawn. Since the panel 19 is substantially flat, the draw molding is a process of forming flanges f on the outer periphery of the blank 19a. In the subsequent piercing step shown in FIG. 4 (C), a large number of small holes h (for example, about 3 mm in diameter) are formed in the blank 19 'by a piercing die (see FIG. 2). Then, in a trim step shown in FIG. 4D, unnecessary portions on the outer periphery of the blank 19 ′ are cut out by a trim mold to complete the panel 19. The outer peripheral surface of the flange f of the panel 19 is fitted to the inner peripheral surface of the opening 18 or the opening 21 and is integrally coupled by welding (see FIG. 3). On the upper surfaces of these panels 19 are adhered sheets 21 with an adhesive provided with an adhesive layer on one side of a synthetic resin sheet, thereby preventing water from entering from the small holes h and so on. Rust on the inner peripheral surface of the hole h is prevented.

  FIG. 5 shows how the tensile stiffness and bending stiffness change when the thickness of the steel plate is reduced and when a large number of small holes h are formed in the steel plate. is there.

  FIG. 5 (A) shows a solid steel plate (having no small holes h) as a base, with a plate thickness of 1.2 mm, and its tensile stiffness and bending stiffness are each 100%.

  Fig. 5 (B) shows the plate thickness reduced from 1.2mm to 1.0mm. The weight decreases by 16% as the plate thickness decreases, and the tensile rigidity decreases by 16% to 84% of the base. The bending stiffness is reduced by 42% to 58% of the base. Thus, when the plate thickness is reduced, the weight is reduced, but naturally the tensile rigidity and bending rigidity are also reduced.

  Fig. 5 (C) shows the plate thickness reduced from 1.2mm to 0.85mm. The weight decreases by 30% as the plate thickness decreases, and the tensile rigidity decreases by 30% to 70% of the base. The bending stiffness is reduced by 66% to 34% of the base.

  FIG. 5D shows a case where small holes h having a diameter of 3 mm are formed at an opening ratio of 30% while the plate thickness is maintained at 1.2 mm which is the same as that of the base. Since the aperture ratio of the small holes h is 30%, the weight is naturally reduced by 30% with respect to the base. Also, the tensile rigidity is reduced by 34% to 66% of the base, and the bending rigidity is reduced by 36% to 64% of the base.

  FIG. 5C in which the plate thickness is reduced with respect to the base to reduce the weight by 30%, and FIG. 5D in which the small holes h are formed in the base to reduce the weight by 30%. As is clear from comparison with (C), the tensile rigidity of (D) is slightly lower than that of (C), but the bending rigidity is significantly increased (about 1.9 times).

  That is, if the small holes h are formed while maintaining the plate thickness instead of reducing the plate thickness to reduce the weight, high bending rigidity can be secured with the same weight and the same tensile rigidity.

  As described above, the panel 19 of the present embodiment can be reduced in weight as compared with a solid panel made of the same material and having the same bending rigidity while having high bending rigidity. Further, the tensile strength of the panel 19 in which a large number of small holes h are perforated decreases. However, by welding the outer periphery of the panel 19 to the inner periphery of the frame member, the shortage of the tensile strength is compensated to reduce the weight. A rigid body part can be obtained. In addition, since the position of the small holes h can be visually confirmed from the outside, it is possible to reliably find a manufacturing defect such as a positional deviation of the small holes h.

  FIG. 6 is a graph of the above description. When the weight is reduced by 30% compared to the base, the solid panel and the panel 19 formed with the small holes h are not much different in tensile rigidity. It can be seen that the bending rigidity of the panel 19 formed with the small holes h is about 1.9 times the bending rigidity of the solid panel.

  These panels 19 are slightly lower in tensile rigidity than solid panels having the same weight, but the outer peripheral surfaces of the panels 19 are side sills 13, 13, a center tunnel 16, a dashboard 12, a middle cross member 14, By welding to the inner peripheral surface of the frame member constituted by the center cross member 15 or the like, the decrease in the tensile rigidity can be sufficiently compensated.

  As shown in FIGS. 1 and 7, of the top, bottom, left, and right surfaces of the front side frame 11, the outer surface to which the connecting member 23 connected to the upper member 22 is connected, and the lower surface to which the front bulkhead 24 is connected. Square-shaped openings 11a and 11a are formed on the upper surface and the inner surface except for and the outer peripheral surfaces of the panels 19 and 19 having the same structure as the panels 19 and 19 described above on the inner peripheral surfaces of these openings 11a and 11a. Are welded.

  According to this structure, the panel 19 having the small holes h can be crushed by the collision load input to the front side frames 11 and 11 when the vehicle collides, and the collision load can be effectively absorbed. At that time, by adjusting the diameter, number, arrangement interval, aperture ratio, and the like of the small holes h, it is possible to arbitrarily adjust the absorption characteristics of the collision load, and of course, to reduce the weight of the front side frames 11, 11. Can also contribute.

  As shown in FIGS. 1 and 8, a bracket 26 that supports the inner surface of the front fender 25 is provided on the upper surface of the upper member 22. The bracket 26 is formed by bending a belt-shaped steel plate into a gate shape, and the lower surfaces of both legs are welded to the upper surface of the upper member 22, and the upper surface is welded to the inner surface of the front fender 25. The outer peripheral surfaces of the panels 19, 19 having the same structure as the panels 19, 19 described above are welded to the openings 26 a, 26 a formed at both legs of the bracket 26.

  According to this structure, while the front fender 25 is reliably supported by the upper member 22 via the bracket 26 at the normal time, when the pedestrian or the like collides with the front fender 25, the panel 19 of the bracket 26 is crushed and collided. The load can be absorbed effectively. Also in this case, the load absorption characteristics can be arbitrarily adjusted by adjusting the diameter, number, arrangement interval, aperture ratio, and the like of the small holes h.

  FIG. 9 shows the back surface of the hood hood 27, and the stiffener of the hood hood 27 is constituted by the panel 19 having the small holes h of the present embodiment. The outer peripheral portion of the panel 19 is fixed to the outer peripheral portion of the back surface of the bonnet hood 27 by caulking, and the edges of the four openings 19 a formed in the middle of the panel 19 are bonded to the back surface of the bonnet hood 27.

  The bonnet hood 27 is formed with small holes h only in the outer peripheral portion and a portion excluding the vicinity of the opening 19a, and the tensile strength is provided between the outer peripheral portion in which the small holes h are not formed and the opening 19a. Can be secured.

  Even with this structure, the hood hood 27 is reinforced by the panel 19 that normally functions as a stiffener, and when the pedestrian or the like collides with the hood hood 27, the panel 19 is crushed to effectively absorb the collision load. Can do. Also in this case, the load absorption characteristics can be arbitrarily adjusted by adjusting the diameter, number, arrangement interval, aperture ratio, etc. of the small holes h, and this contributes to the reduction in the weight of the stiffener of the hood hood 27. Can do.

  FIG. 10 shows another embodiment of the panel 19.

  In these embodiments, the small holes h are not formed at least on the outer peripheral portion of the panel 19, and the tensile strength of the panel 19 is secured at that portion. Further, even in the portion excluding the outer peripheral portion of the panel 19, small holes h are not formed in the portion that requires strength, so that both the weight reduction and the bending rigidity of the panel 19 are more effectively achieved. Can be made.

  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, in the embodiment, the panel 19 is applied to the floor of the vehicle body, the front side frame, the bracket that supports the front fender, and the stiffener of the bonnet hood, but the application portion is arbitrary.

  Further, the diameter, number, arrangement interval, aperture ratio, and the like of the small holes h of the panel 19 can be changed as appropriate according to the portion used. Of course, the diameter, number, arrangement interval, aperture ratio, etc. of the small holes h may be changed for each part of the panel 19.

  In addition, the order of the draw process and the piercing process may be interchanged, and the piercing process may be performed simultaneously with the process behind the draw process and the piercing process.

  The means for fixing the panel 19 to the vehicle body is not limited to welding, and any means such as bolting, adhesion, caulking, etc. can be employed.

Perspective view of car body frame 2 direction enlarged view of FIG. 3-3 enlarged sectional view of FIG. Illustration of panel manufacturing process Diagram illustrating the effect of panel thickness and small hole aperture ratio on panel weight, tensile stiffness and bending stiffness Graph showing the characteristics of tensile stiffness and bending stiffness with respect to the weight of panels with different plate thicknesses and aperture ratios of small holes 7 direction enlarged arrow view of FIG. 8 direction enlarged arrow view of FIG. Illustration showing the back of the hood The figure which shows other embodiment of a panel

Explanation of symbols

19 Panel 19 ′ Blank 21 Adhesive sheet h Small hole

Claims (6)

  A vehicle body part characterized in that a large number of small holes (h) are perforated in a portion excluding at least the outer peripheral portion of the panel (19).   The vehicle body part according to claim 1, characterized in that a large number of small holes (h) drilled in the panel (19) are covered with a sheet (21) with adhesive.   Car body part according to claim 1, characterized in that the panel (19) is arranged in a part that collapses in the event of a collision.   The body part according to claim 1, wherein the small hole (h) of the panel (19) is formed except for a portion requiring strength. A blank process of punching a blank (19 ') of a predetermined shape from a plate material;
A drawing step of drawing the blank (19 ′) into a predetermined shape;
A piercing step of drilling a number of small holes (h) in the drawn panel (19);
A trim step of cutting off unnecessary portions of the outer periphery of the pierced panel (19);
A fixing step of fixing the trimmed panel (19) to the vehicle body;
A method of manufacturing a vehicle body part comprising: A blank process of punching a blank (19 ') of a predetermined shape from a plate material;
A piercing step of drilling a number of small holes (h) in the blank (19 ');
A drawing process of drawing a pierced blank (19 ') into a predetermined shape;
A trim step of cutting off unnecessary portions on the outer periphery of the panel (19) that has been drawn;
A fixing step of fixing the trimmed panel (19) to the vehicle body;
A method of manufacturing a vehicle body part comprising:

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