JP2009280106A - Vehicle frame structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain inertial shift of a fuel tank upon offset collision against a side rail on a fuel tank side. <P>SOLUTION: A frame structure is provided with side rails 16 extending in the vehicle lengthwise direction on both sides in a vehicle cross direction, and a cross member 14 which is configured such that each of both the side rails 16 is connected in the vehicle cross direction and the fuel tank 10 is supported in such a state as to be moved to one side in the vehicle cross direction, and which includes a maximum section modulus on the fuel tank 10 side. Thus, deformation of the cross member 14 on the fuel tank 10 side can be restrained when offset collision occurs against the side rail 16 on the fuel tank 10 side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle frame structure.

As a lower body structure of an automobile, side frames extending in the longitudinal direction of the vehicle body are provided on both sides of the vehicle body, and are provided at the same position of the left and right side frames in at least one of the front half or the rear half of the vehicle body. The distance between the left and right side frames is reduced toward the rear, and in the latter half, the distance between the left and right side frames is reduced toward the rear end, and the vehicle width is provided on the vehicle body front and rear end sides. A first cross member that extends between the bent portion and the bent portion on the side where the distance between the left and right side frames is small, and is extended in the vehicle body width direction, and is extended in the vehicle body width direction and has a large distance between the left and right side frames. A structure is disclosed that includes a second cross member that connects the bent portions on the side and an impact absorbing portion provided on the first cross member (see Patent Document 1).
JP-A-8-268326 JP 2003-26049 A JP-A-11-78959

  Generally, in a vehicle with a frame, the fuel tank is held at a position close to the cross member below the vehicle and one side rail.

  However, in the above-described conventional example, the main object is to convert the load in the longitudinal direction of the vehicle body into the load in the vehicle body width direction and absorb it, and no consideration is given to the offset collision with the side rail on the fuel tank side. Not.

  An object of the present invention is to suppress the inertial movement of the fuel tank at the time of an offset collision with the side rail on the fuel tank side in view of the above fact.

  The invention according to claim 1 is a state in which the side rails extending in the vehicle longitudinal direction on both sides in the vehicle width direction and the side rails on both sides are connected in the vehicle width direction, respectively, and the fuel tank is brought close to one side in the vehicle width direction. And a cross member whose section modulus is maximized on the fuel tank side.

  In the vehicle frame in which the fuel tank is supported on one side of the cross member in the vehicle width direction, when an offset collision with the side rail on the fuel tank side occurs, the inertia of the fuel tank is placed on the fuel tank side of the cross member. Force is input.

  At this time, in the vehicle frame structure according to the first aspect, since the cross section coefficient of the cross member is maximized on the fuel tank side, deformation of the cross member on the fuel tank side can be suppressed. For this reason, the inertial movement of the fuel tank at the time of an offset collision with the side rail on the fuel tank side can be suppressed.

  According to a second aspect of the present invention, in the vehicle frame structure according to the first aspect, a reinforcing member is provided at an end of the cross member on the fuel tank side.

  In the vehicle frame structure according to the second aspect, the reinforcing member is provided at the end of the cross member on the fuel tank side, and the section modulus of the end is increased by the reinforcing member. As a result, the end of the cross member on the fuel tank side of the cross member can be reinforced at a low cost, and the inertial movement of the fuel tank at the time of an offset collision to the fuel tank side can be suppressed.

  According to a third aspect of the present invention, in the vehicle frame structure according to the second aspect, the reinforcing member is fixed to the end portion of the cross member and the side rail on the end portion side.

  In the vehicle frame structure according to claim 3, since the reinforcing member is fixed to the end of the cross member on the fuel tank side and the side rail on the end side, the end of the cross member on the fuel tank side The joint strength between the portion and the side rail can be further increased. Thereby, the inertial movement of the fuel tank at the time of an offset collision with the side rail on the fuel tank side can be more stably suppressed.

  According to a fourth aspect of the present invention, in the vehicle frame structure according to any one of the first to third aspects, the cross-section coefficient of the cross member is minimized at the center in the vehicle width direction.

  In the vehicle frame structure according to claim 4, since the cross-sectional modulus of the cross member is minimized at the center portion in the vehicle width direction, the cross member in the vehicle width direction at the time of an offset collision with the side rail on the fuel tank side The central portion can be relatively easily deformed by the inertia force of the fuel tank. For this reason, the moment which acts on a cross member by the inertial force of a fuel tank can be suppressed, and the attitude change of a fuel tank can be controlled.

  The invention according to claim 5 is the vehicle frame structure according to claim 4, wherein the vehicle width direction center portion of the cross member has a curved shape so as to protrude toward the vehicle upper side.

  In the vehicle frame structure according to claim 5, since the vehicle width direction center portion of the cross member is curved so as to protrude toward the vehicle upper side, the vehicle width direction center portion is further weakened. The section modulus is also set lower. For this reason, at the time of an offset collision with the side rail on the fuel tank side, the center part in the vehicle width direction of the cross member is more easily deformed, and the moment acting on the cross member is suppressed, and the change in the posture of the fuel tank is further suppressed. can do.

  As described above, according to the vehicle frame structure according to claim 1 of the present invention, it is possible to suppress the inertial movement of the fuel tank at the time of an offset collision with the side rail on the fuel tank side. Excellent effect is obtained.

  According to the vehicle frame structure of the second aspect, the end of the cross member on the fuel tank side is reinforced at a low cost to suppress inertial movement of the fuel tank at the time of an offset collision to the fuel tank side. An excellent effect is obtained.

  According to the vehicle frame structure of the third aspect, an excellent effect is obtained that inertial movement of the fuel tank at the time of offset collision with the side rail on the fuel tank side can be more stably suppressed. It is done.

  According to the vehicle frame structure of the fourth aspect, an excellent effect is obtained in that the moment acting on the cross member by the inertia force of the fuel tank can be suppressed, and the change in the posture of the fuel tank can be suppressed. .

  According to the vehicle frame structure of the fifth aspect, in the event of an offset collision with the side rail on the fuel tank side, the center portion in the vehicle width direction of the cross member is more easily deformed to suppress the moment acting on the cross member. And the outstanding effect that the attitude | position change of a fuel tank can be suppressed further is acquired.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, a vehicle frame structure S according to the present embodiment relates to a frame structure in a vehicle with a frame (not shown), and includes a side rail 16 and a cross member 14.

  The side rails 16 are skeleton members that extend in the vehicle front-rear direction on both sides in the vehicle width direction, and a pair of side rails 16 are provided on the left and right sides of the vehicle frame structure S. As shown in FIG. 3, the side rails 16 are joined with, for example, steel materials having a U-shaped cross section facing each other in the vehicle width direction, and have a hollow and rectangular closed cross section. As shown in FIG. 1, the distance between the left and right side rails 16 in the front portion 16F is narrower than the center portion 16C in consideration of the arrangement of front wheels (not shown). For this reason, in the region from the front portion 16F to the central portion 16C of the side rail 16, for example, bent portions 16A and 16B exist. In a plan view of the vehicle, the center of curvature (not shown) of the bent portion 16A is located on the outer side in the vehicle width direction than the side rail 16, and the center of curvature (not shown) of the bent portion 16B is closer to the vehicle than the side rail 16. Inside in the width direction.

  As shown in FIG. 1, the left and right side rails 16 are connected by a front suspension member 18 and a plurality of cross members 11, 12, 13, 14, 15, etc., so that the vehicle frame structure S is ladder-shaped. It is configured. The components provided on the side rail 16 include a cab mount bracket 20 that protrudes outward in the vehicle width direction between the bent portions 16A and 16B, and a front suspension that protrudes outward in the vehicle width direction at the front portion 16F. There are a mounting bracket 22 and the like. A bumper reinforcement 26 is provided at the front end of the front portion 16F of the side rail 16 via a so-called crash box 23.

  The cross member 14 is configured to connect, for example, the central portion 16C of the side rails 16 on both sides in the vehicle width direction, and to support the fuel tank 10 in a state of being brought close to one side in the vehicle width direction, for example, the left side of the vehicle. This is a skeleton member having a maximum section modulus on the fuel tank 10 side. The cross member 14 is located, for example, at the fourth position from the cross member 11 on the most front side of the vehicle. The cross member 14 is formed by press-molding a steel plate into a reverse hat shape in cross section, for example.

  A reinforcing member 24 is provided at the end 14A of the cross member 14 on the fuel tank 10 side. A part corresponding to the reinforcing member 24 is not provided at an end portion 14B of the cross member 14 on the opposite side of the fuel tank 10 (right side of the vehicle in the illustrated example). Thereby, the cross-section coefficient of the cross member 14 is set to be maximum at the end portion 14A on the fuel tank 10 side.

  As shown in FIGS. 3 and 4, the end 14 </ b> A on the fuel tank 10 side of the cross member 14 is the vehicle width of the general portion 14 </ b> D extending in the vehicle width direction when viewed from the vehicle front-rear direction. It extends obliquely downward from the outer side end portion toward the outer side in the vehicle width direction, and is joined to the lower portion of the side wall portion 16D on the inner side in the vehicle width direction of the side rail 16 at the flange 14G. The same applies to the end portion 14B opposite to the fuel tank 10.

  As shown in FIG. 2 to FIG. 4, the reinforcing member 24 is, for example, a steel plate patch, and the general portion 24A is connected to the front and rear flange portions 14F of the end portion 14A on the fuel tank 10 side of the cross member 14. It is overlapped and joined from the upper side of the vehicle. That is, the end portion 14A has a partially closed cross-sectional structure. Thereby, the section modulus of the end portion 14A is increased. For example, the general portion 24A of the reinforcing member 24 extends not only to the region of the end portion 14A but also to the region of the general portion 14D, and is joined to the flange portion 14F. This is because the bent portion 14E extending from the end portion 14A to the general portion 14D is reinforced to increase the section modulus of the bent portion. For example, a substantially V-shaped notch 24K is formed at the inner edge in the vehicle width direction of the general portion 24A. The notch 24K is provided to reduce the weight of the reinforcing member 24.

  As shown in FIGS. 3 and 4, the reinforcing member 24 is fixed to the side rail 16 on the end portion 14 </ b> A side in addition to the end portion 14 </ b> A of the cross member 14. Specifically, in the reinforcing member 24, an extended portion 24B extending outward in the vehicle width direction is provided at the end of the general portion 24A on the outer side in the vehicle width direction. A flange 24 </ b> C is bent at the vehicle width direction end edge of the extended portion 24 </ b> B in the vehicle vertical direction, and the flange 24 </ b> C is joined to the upper portion of the side wall portion 16 </ b> D of the side rail 16.

  On the other hand, as shown in FIGS. 3 and 4, the center portion 14 </ b> C in the vehicle width direction of the cross member 14 has a curved shape so as to protrude toward the vehicle upper side. The vehicle width direction center portion 14C is set such that the vehicle vertical direction dimension (height dimension) is smaller than, for example, the end portion 14A and the general portion 14D. As a result, the cross-section coefficient of the cross member 14 is minimized at the center 14C in the vehicle width direction. The means for reducing the section modulus of the central portion 14C in the vehicle width direction is not limited to the curved shape and height dimension, and is a configuration that weakens the central portion 14C in the vehicle width direction by providing beads, grooves, holes, and the like. May be.

  As shown in FIGS. 1 and 2, the fuel tank 10 uses a tank band (not shown) and the front side portion 10F is held by, for example, the fourth cross member 14, and the rear side portion 10R is 5%. The second cross member 15 holds it. As shown in FIGS. 3 and 4, the fuel tank 10 is disposed on the vehicle lower side of the cross member 14. In addition, the fuel tank 10 has, for example, a shape along a general portion 14D extending in the vehicle width direction in the cross member 14 and an end portion 14A inclined with respect to the general portion 14D. This is to stabilize the holding state of the fuel tank 10 in the cross member 14.

  A groove-shaped recess corresponding to the tank band or the cross members 14 and 15 may be provided on the surface of the fuel tank 10. This is because the holding state of the fuel tank 10 in the cross members 14 and 15 is further stabilized.

(Function)
This embodiment is configured as described above, and the operation thereof will be described below. In FIG. 5, in the vehicle frame in which the fuel tank 10 is supported on one side of the cross member 14 in the vehicle width direction, an offset collision occurs on the side rail 16 on the fuel tank 10 side, that is, on the left side of the vehicle. When the collision load F is input to 16, the inertia force of the fuel tank 10 is input to the front side of the vehicle on the fuel tank 10 side of the cross member 14.

  In the vehicle frame structure S according to the present embodiment, of the front cross member 14 that holds the fuel tank 10, the end 14 </ b> A on the fuel tank 10 side is reinforced by the reinforcing member 24. Since the section modulus is maximized at the end 14A on the fuel tank 10 side, deformation of the cross member 14 on the fuel tank 10 side can be suppressed. In particular, the reinforcing member 24 is fixed not only to the end 14A on the fuel tank 10 side of the cross member 14 but also to the side rail 16 on the end 14A side, so that the end of the cross member 14 on the fuel tank 10 side is fixed. The coupling strength between the portion 14A and the side rail 16 can be further increased. By using the reinforcing member 24 to reinforce the end portion 14A, the cross member 14 can be formed in a symmetrical shape in the vehicle width direction, and the end portion 14A can be reinforced at low cost.

  On the other hand, at the time of the offset collision, the fuel tank 10 tends to rotate relative to the cross member 14 in the clockwise direction (arrow R direction) with respect to the cross member 14 due to inertia. A moment will act. At this time, in the vehicle frame structure S according to the present embodiment, the center part 14C in the vehicle width direction of the cross member 14 is curved so as to protrude upward in the vehicle, and the cross-section coefficient of the cross member 14 is Since it is the smallest in the vehicle width direction center portion 14C, the vehicle width direction center portion 14C of the cross member 14 can be relatively easily deformed by the inertial force of the fuel tank 10, as shown in FIG. it can.

  When the center part 14C in the vehicle width direction of the cross member 14 is deformed, the moment around the vehicle right direction acting on the cross member 14 is canceled out. As a result, the fuel tank 10 that is about to rotate relative to the cross member 14 around the right side of the vehicle is rotated relative to the left side of the vehicle (in the direction of arrow L). As a result, the posture change of the fuel tank 10 is suppressed, and the holding state of the fuel tank 10 in the cross member 14 is stably maintained.

  Thus, in the vehicle frame structure S according to the present embodiment, by using the reinforcing member 24, the end 14A of the cross member 14 on the fuel tank 10 side is reinforced at a low cost, and the fuel tank 10 side of the fuel tank 10 side is thus reinforced. The inertial movement of the fuel tank 10 at the time of an offset collision with the side rail 16 can be stably suppressed.

  The reinforcing member 24 is not limited to the above configuration and the illustrated example. For example, the reinforcing member 24 may be joined only to the end portion 14A of the cross member 14 and not joined to the side rail 16. Further, a member corresponding to the reinforcing member 24 may be added to the cross member 15 that holds the rear side portion 10 </ b> R of the fuel tank 10. This is because the holding state of the fuel tank 10 at the time of the offset collision is further stabilized.

  Although the state where the fuel tank 10 is moved toward the left side of the vehicle has been described, the present invention is not limited to this, and a configuration where the fuel tank 10 is moved toward the right side of the vehicle may be employed.

  In the cross member 14, it has been described that the section modulus of the end portion 14 </ b> A located on the fuel tank 10 side is maximized and the section modulus of the center portion 14 </ b> C in the vehicle width direction is minimized. As long as the inertial movement of the fuel tank 10 can be suppressed at the time of an offset collision with the rail 16, the section coefficient of the center portion 14C in the vehicle width direction need not be set to the minimum. That is, the section modulus of the central portion 14C in the vehicle width direction may be set as appropriate according to the configuration and arrangement of the fuel tank 10, the deformation mode of the cross member 14, etc. May be.

It is a top view which shows the frame structure for vehicles. FIG. 2 is an enlarged plan view showing a fuel tank attachment site in a vehicle frame structure. It is a perspective view which shows the attachment site | part of a fuel tank in the frame structure for vehicles. FIG. 2 is a rear view showing a fuel tank attachment site as seen from the vehicle rear side in the vehicle frame structure. It is a top view which shows the initial behavior of a fuel tank when the offset collision to the side rail on the fuel tank side has occurred. It is a top view which shows the state by which the attitude | position change of a fuel tank is suppressed by deform | transforming the vehicle width direction center part by which the section modulus is made into the minimum among cross members.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel tank 14 Cross member 14A Fuel tank side edge part 14C Vehicle width direction center part 16 Side rail 24 Reinforcement member S Vehicle frame structure

Claims (5)

Side rails extending in the vehicle longitudinal direction on both sides in the vehicle width direction,
A cross member configured to connect the side rails on both sides in the vehicle width direction and to support the fuel tank in a state of being brought close to one side in the vehicle width direction, and having a maximum section modulus on the fuel tank side; ,
A vehicle frame structure.   The vehicle frame structure according to claim 1, wherein a reinforcing member is provided at an end of the cross member on the fuel tank side.   The vehicle frame structure according to claim 2, wherein the reinforcing member is fixed to the end portion of the cross member and the side rail on the end portion side.   The vehicle frame structure according to any one of claims 1 to 3, wherein a cross-section coefficient of the cross member is minimized at a center portion in a vehicle width direction.   5. The vehicle frame structure according to claim 4, wherein a central portion of the cross member in the vehicle width direction is curved so as to protrude toward the vehicle upper side.

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