JP2010143446A - Body frame structure of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a body frame structure of a vehicle suppressing manufacturing cost while reducing weight, and moreover, stably absorbing a collisional energy with little secular variation. <P>SOLUTION: Excluding at least ridgelines 71-74 and mating faces, a plurality of pores 24 are opened in a frame member 25. To the mating face arranged in the backside of this frame member 25, a reinforcing member 26 is joined by welding. In this reinforcing member 26, long holes 61 directed in the longitudinal direction relative to a load input direction are opened. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement in a vehicle body frame structure.

As a conventional vehicle body frame structure, a structure in which a reinforcing plate is disposed in a closed cross-section structural member is known (see, for example, Patent Document 1).
JP-A-9-295160

1 and 2 of Patent Document 1 will be described with reference to FIGS. 8 and 9 below. In addition, the code | symbol was reassigned.
FIG. 8 is a perspective view showing a conventional vehicle body frame structure, in which flanges 102 and 103 are provided below a side member 101 having a hat-shaped cross section, and a closing plate 104 is attached to the flanges 102 and 103 with a plurality of spot welds 106. It is joined with.

  FIG. 9 is a cross-sectional view showing a conventional vehicle body frame structure, in which a reinforcing plate 107 is joined to the inner surface of the ceiling portion of the side member 101 by an adhesive joint 108 using spot welding.

  By joining the reinforcing plate 107 in a closed cross-section structural member composed of the side member 101 and the closing plate 104 by jointing with spot welding, the amount of energy absorbed at the time of a vehicle collision compared to the case of only welding alone. However, no special measures to reduce the weight are taken and the weight of the closed cross-section structural member increases.

Moreover, since an adhesive agent is used, the adhesive application process increases and the production cost increases.
Furthermore, considering the secular change such as deterioration due to the nature of the adhesive, there remains a problem in performance assurance when used for a collision member that absorbs collision energy.
An object of the present invention is to provide a vehicle body frame structure that can reduce the production cost while reducing the weight, and can stably absorb the collision energy with little secular change.

  In the invention according to claim 1, a plurality of fine holes are formed in the frame member except at least the ridge line and the mating surface, and the reinforcing member is joined to the mating surface provided on the back surface of the frame member by welding. The reinforcing member is characterized in that a long hole is formed in the longitudinal direction with respect to the load input direction.

By making a plurality of fine holes except for the ridgeline and the mating surface that tend to increase the load acting on the frame member, the weight can be reduced and the strength and rigidity of the frame member can be ensured.
In addition, when reinforcing by adding a reinforcing member to the frame member, the weight reduced by the long hole opened in the reinforcing member increases, and the longitudinal direction of the long hole faces the load input direction. For this reason, the cross-sectional area of the long hole in the direction orthogonal to the load input direction is reduced, and sufficient rigidity can be easily obtained with respect to the load input to the reinforcing member.
Furthermore, since the frame member and the reinforcing member are joined by welding, there is little change in strength and rigidity due to secular change as in the case of using a conventional adhesive.

  In the invention according to claim 1, a plurality of fine holes are formed in the frame member except at least the ridge line and the mating surface, and the reinforcing member is joined to the mating surface provided on the back surface of the frame member by welding. Since the reinforcing member has a long hole that faces the longitudinal direction with respect to the load input direction, it is possible to reduce the weight more effectively with the fine hole and the long hole of the frame member, and in the load input direction. On the other hand, by opening a long hole facing the longitudinal direction in the reinforcing member, a decrease in rigidity in the load input direction of the reinforcing member can be suppressed, and when the structural member is configured by the frame member and the reinforcing member, It is easy to ensure rigidity.

  In addition, since no adhesive is used for joining the frame member and the reinforcing member, changes in strength and rigidity due to secular change can be suppressed, and performance guarantee as a collision member can be satisfied.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the description, left, right, front, and rear indicate directions based on the driver who has boarded the vehicle. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a perspective view of an underbody showing a vehicle body frame structure according to the present invention, and an arrow (FRONT) in the figure represents the front of the vehicle (the same applies hereinafter).
The underbody 10 constitutes a part of the front floor panel 11, side sills 12 and 13 attached to the left and right ends of the front floor panel 11 so as to extend in the front-rear direction, and a part of the front floor panel 11. A structural member 17 attached to the left floor portion 14 and the right floor 16 which are divided in the left and right directions by a tunnel portion 11a formed to extend in the front-rear direction in the vehicle width direction central portion of the vehicle 11; 11a and left and right side sills 12 and 13, seat cross members 18 and 19 and middle floor frames 21 and 22 that are attached to the rear portion of the front floor panel 11 and joined to the rear ends of the structural members 17 and 17 Prepare. Reference numeral 23 denotes a dashboard lower joined to the front end of the front floor panel 11, and the front ends of the structural members 17, 17 are joined to the dashboard lower 23.

  FIG. 2 is an exploded perspective view showing a structural member according to the present invention. The structural member 14 is joined to a frame member 25 having a plurality of circular fine holes 24 for weight reduction and the inside of the frame member 25. The reinforcing member 26 is made of.

  The frame member 25 includes a frame main body 35 having hole dense portions 27 to 29 in which the fine holes 24 are dense, and the front floor panel 11 (see FIG. 1) and the dashboard lower 23 (see FIG. 1) on the left and right sides of the frame main body 35. Left flange 36 and right flange 37, which are integrally formed to join to the dashboard lower 23, a front flange 38 formed at the front end to join the dashboard lower 23, and middle floor frames 21, 22 (see FIG. 1). And a rear joint portion 39 formed at the rear end portion for joining to the rear end portion.

  The frame main body 35 includes an upper wall 43 and side walls 44 and 45 (only the reference numeral 44 on the front side is shown) extending downward from the left and right edge portions of the upper wall 43, and a plurality of hole dense portions 27 are formed on the upper wall 43. And a plurality of hole dense portions 28 and a hole dense portion 29 are provided on the side wall 44 and the side wall 45, respectively.

  The upper wall 43 has an endless shape connecting the upper wall base 47, a lower wall portion 48 formed one step lower than the upper wall base 47, and each of the upper wall base 47 and the lower wall portion 48. It consists of a slant wall 49.

The left flange 36 and the right flange 37 are formed such that the front end side is curved upward together with the lower portion of the front end of the frame main body 35.
The front flange 38 is a portion extending obliquely forward and upward from the front end of the upper wall 43 of the frame body 35.
The rear joint portion 39 is a portion formed in a U-shaped cross-sectional shape that has a narrowed cross-sectional shape and is smaller than the cross-sectional shape of the frame main body 35.

The reinforcing member 26 includes an upper wall 51 and side walls 52 and 53 extending downward from left and right end portions of the upper wall 51.
The upper wall 51 includes a left base portion 55 and a right base portion 56 that are formed so as to extend back and forth on the left and right end sides, a low wall portion 57 that is formed one step lower than the left base portion 55 and the right base portion 56, and a left base portion. 55 and the bottom base 57, the slant wall 58 connecting between the right base 56 and the low wall 57, and the bottom wall 57 have a longitudinal direction for weight reduction. It consists of a plurality of elongated holes 61 formed so as to face in the front-rear direction, and a plurality of upper raised portions 62 protruding upward and formed in the bottom wall portion 57 so as to be positioned between the elongated holes 61.
The upper raised portion 62 is joined by spot welding or the like to the upper wall 43 of the frame member 25, specifically, to the lower wall portions 48 of the non-hole forming portions 60, 63, 64 where the hole dense portions 27 of the upper wall 43 are not provided. It is a part to be done.

The side wall 52 includes a side base 65 and a plurality of side ridges 66 projecting laterally from the side base 65.
Similarly, the side wall 53 is composed of a side base 67 (see FIG. 3) and a plurality of side ridges 68 that protrude from the side base 67 to the side.

  The side raised portions 66 and 68 are formed in the non-hole forming portions 69 and 70 (the inner surfaces 44a and 45a (see FIG. 3) thereof) where the hole dense portions 28 and 29 of the side walls 44 and 45 of the frame member 25 are not provided, respectively. It is a part joined by spot welding or the like.

  3 is a cross-sectional view taken along the line 3-3 in FIG. 2. The structural member 14 includes a frame member 25 having a hat-shaped cross section and a reinforcing member 26 having a U-shaped cross section joined to the inside of the frame member 25. The frame member 25 is reduced in weight by providing a plurality of dense hole portions 27 to 29 (only reference numeral 27 is shown), and the reinforcement member 26 is reduced in weight by being provided with a plurality of elongated holes 61. The reinforcing member 26 reinforces the frame member 25 to reduce the weight of the structural member 14 and improve the strength and rigidity.

  The upper raised portion 62 of the reinforcing member 26 is joined to the lower surface 43 a of the lower wall portion 48 of the upper wall 43 in the frame member 25, and the side raised portions 66 and 68 of the reinforcing member 26 are the side walls 44 and 45 of the frame member 25. Are joined to the inner surfaces 44a and 45a, respectively.

A ridge line 71 is formed at the corner between the upper wall 43 and the side wall 44 of the frame member 25, and a ridge line 72 is formed at the corner between the upper wall 43 and the side wall 45. A ridgeline 73 is formed at a corner between the ridgeline 74 and a ridgeline 74 is formed at a corner between the side wall 45 and the right flange 36.
A ridge line 76 is formed at the corner between the upper wall 51 and the side wall 52 of the reinforcing member 26, and a ridge line 77 is formed at the corner between the upper wall 51 and the side wall 53.

4A to 4C are explanatory views for explaining a structural member according to the present invention.
(A) is a top view of the frame member 25, and the frame member 25 is formed so that the left and right widths become wider as the front part goes forward. That is, the left and right widths of the upper wall 43 gradually increase, and the side walls 44, 45, the left flange 36, and the right flange 37 extend forward so as to gradually spread outward in the vehicle width direction.
The rear joint portion 39 is not provided with the fine holes 24 for joining the middle floor frames 21 and 22 (see FIG. 1).
The imaginary line in the figure indicates the upper raised portion 62 and the side raised portions 66 and 68 of the reinforcing member 26 (see FIG. 4C) joined to the frame member 25 from below.

(B) is a plan view of the hole dense portion 27, in which the fine holes 24 are formed in parallel in the vertical and horizontal directions.
Assuming that the inner diameter of the fine holes 24 is D1 and the pitch between the fine holes 24 is P1, for example, D1 = 3 mm and P1 = 5 mm. The fine holes 24 are also formed in the other hole dense portions in the same manner as the hole dense portion 27.

  (C) is a top view of the reinforcing member 26, and the reinforcing member 26 is formed such that the left and right widths become wider as the front part moves forward. That is, the left and right widths of the upper wall 51 are gradually widened, and accordingly, the side walls 52 and 53 extend forward so as to gradually spread outward in the vehicle width direction.

  The long holes 61 and the upper raised portions 62 are provided at equal intervals in the front-rear direction. Further, the side raised portions 66 and the side raised portions 68 are also provided at equal intervals in the front-rear direction.

  FIG. 5 is an explanatory view showing another embodiment of the arrangement of the fine holes of the frame member according to the present invention. In the dense hole portion 27A, the fine holes 24 are formed in a staggered manner. That is, a triangle connecting the centers of the three fine holes 24 becomes a regular triangle.

  If the inner diameter of the micro holes 24 is D2, the distance between the centers of the adjacent micro holes 24 is P3, and the pitch between the micro holes 24 arranged vertically is P4, for example, D2 = 3 mm, P3 = 5 mm, P4 = √3 × P3 is there.

6 (a) and 6 (b) are operation diagrams for explaining the strength and rigidity of the structural member according to the present invention. Both (a) and (b) schematically show the frame member 25 and the reinforcing member 26. FIG. .
In (a), when the frame member 25 and the reinforcing member 26 are pulled or compressed in the longitudinal direction of the vehicle body, that is, in the longitudinal direction, as indicated by the white arrows, the fine holes 24 are formed at equal intervals in the frame member 25. Since the inner diameter of the fine hole 24 is small, the portion between the fine holes 24 and 24 is subjected to a tensile force or a compressive force, and the strength / rigidity is hardly lowered. In addition, the reinforcing member 26 has a long hole in the longitudinal direction. 61 is opened, but the cross-sectional area of the elongated hole 61 in the direction orthogonal to the longitudinal direction (that is, the vehicle width direction) is reduced, and further, the tensile force or the compressive force is applied to the left base portion 55 and the right base portion of the upper wall 51. 56, and there is little decrease in strength and rigidity.

  On the other hand, when the frame member 25 and the reinforcing member 26 are pulled or compressed in the vehicle width direction, that is, the direction orthogonal to the longitudinal direction, as shown by white arrows in FIG. Since the fine holes 24 are formed at equal intervals in the vertical and horizontal directions, as in the case of (a), there is little decrease in strength and rigidity, but in the reinforcing member 26, the long holes 61 are perpendicular to the longitudinal direction. When tensile force or compressive force is applied, the cross-sectional area of the elongated hole 61 in the direction perpendicular to the longitudinal direction becomes larger than in the case of (a), the deformation of the elongated hole 61 tends to be large, and the strength and rigidity are greatly reduced. Become.

  Therefore, as shown in (a), by opening the long hole 61 along the longitudinal direction in the reinforcing member 26, the strength and rigidity of the reinforcing member 26 are prevented from being lowered against the tension or compression in the longitudinal direction of the vehicle body. However, weight reduction can be achieved. Further, the frame member 25 can supplement the tensile force or the compressive force in the direction perpendicular to the longitudinal direction acting on the reinforcing member 26 with the strength and rigidity.

  FIG. 7 is a graph showing the relationship between an increase in displacement and a reduction in weight when a load is applied to the structural member according to the present invention. Here, a predetermined load is applied from the front to the front end of the structural member, and the front end of the structural member is shown. The result of measuring the displacement in the vertical direction is shown.

  The samples are roughly classified into (1) frame member + reinforcing member (that is, a member in which the reinforcing member is joined) and (2) only the reinforcing member.

  More specifically, in the frame member + reinforcing member of (1), the example is a combination of the frame member 25 and the reinforcing member 26 of the present embodiment, and the base material has fine holes 24 formed in the example. The combination of the frame member and the reinforcing member in which the long hole 61 is not opened compared to the embodiment, and the comparative example is a combination of the frame member and the reinforcing member whose thickness is reduced relative to the base material. is there.

  With only the reinforcing member (2), the example is the reinforcing member 26 of the present embodiment, the base material is not provided with the long hole 61 as compared with the example, and the comparative example is a plate with respect to the base material. The thickness is reduced.

  The vertical axis of the graph is the displacement increase rate (ratio of the increased displacement amount of each sample to the displacement amount of the base material (unit:%)), and the horizontal axis is the weight reduction rate (ratio of the weight reduction weight of each sample to the weight of the base material) (Unit is%)). A large displacement increase rate on the vertical axis means that the displacement increase with respect to the base material is large and the rigidity is small.

  In the case of only the reinforcing member, for example, when it is assumed that the displacement increase rate of the comparative example increases linearly as the weight reduction rate increases, the displacement increases when the example and the comparative example have the same weight reduction rate. The rate is smaller in the example than in the comparative example. That is, even if the weight reduced is the same, the increase in displacement (that is, the decrease in rigidity) is smaller in the embodiment, and it is easier to ensure a predetermined rigidity.

  In the case of the frame member + reinforcing member, the same tendency as in the case of only the reinforcing member is observed, and the displacement increase rate of the example is smaller than the displacement increase rate of the comparative example. In other words, compared to reducing the thickness by reducing the plate thickness as in the comparative example, it is easier to ensure rigidity and reducing the weight by opening fine holes and elongated holes as in the example, which is more effective. It can be said that this is a lightweight method.

  2 and 3, the frame member 25 has at least ridge lines 71 to 74, and a lower surface 43a and inner surfaces 44a and 45a as mating surfaces of the non-hole forming portions 60, 63, 64, 69, and 70. A plurality of fine holes 24 are formed except for the above, and the reinforcing member 26 is welded to the lower surface 43a and the inner surfaces 44a, 45a of the non-hole forming portions 60, 63, 64, 69, 70 provided on the back surface of the frame member 25. And the reinforcing member 26 is provided with a long hole 61 that is oriented in the longitudinal direction with respect to the load input direction. Therefore, the fine hole 24 and the long hole 61 of the frame member 25 can reduce the weight more effectively. It is possible to reduce the rigidity of the reinforcing member 26 in the load input direction, and the frame member 25 and the reinforcing member 2 can be prevented by opening the reinforcing member 26 with the long hole 61 that is oriented in the longitudinal direction with respect to the load input direction. When configuring the structural member 14 in a can easily secure a predetermined rigidity of the structural member 14.

  In addition, since no adhesive is used for joining the frame member 25 and the reinforcing member 26, changes in strength and rigidity due to aging can be suppressed, and the performance guarantee of the structural member 14 as a collision member can be satisfied. .

  In the embodiment, as shown in FIGS. 4A and 4C, the elongated hole 61, the upper raised portion 62, and the side raised portions 66 and 68 are provided at equal intervals. It may be changed.

  The vehicle body frame structure of the present invention is suitable for a four-wheeled vehicle.

It is a perspective view of the underbody which shows the vehicle body frame structure which concerns on this invention. It is a disassembled perspective view which shows the structural member which concerns on this invention. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. It is explanatory drawing explaining the structural member which concerns on this invention. It is explanatory drawing which shows another embodiment of arrangement | positioning of the fine hole of the frame member which concerns on this invention. It is an effect | action figure explaining the intensity | strength and rigidity of the structural member which concerns on this invention. It is a graph which shows the relationship between the increase in displacement when a load acts on the structural member which concerns on this invention, and weight reduction. It is a perspective view which shows the conventional vehicle body frame structure. It is a cross-sectional view showing a conventional body frame structure.

Explanation of symbols

  24 ... fine hole, 25 ... frame member, 26 ... reinforcing member, 43a, 44a, 45a ... mating surface (lower surface, inner surface, inner surface), 61 ... elongated hole, 71-74 ... ridgeline.

Claims (1)

  A plurality of fine holes are formed in the frame member except at least the ridge line and the mating surface, and a reinforcing member is joined to the mating surface provided on the back surface of the frame member by welding. A vehicle body frame structure characterized in that a long hole facing the longitudinal direction is formed.

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