WO2016035506A1

WO2016035506A1 - Vehicle body frame structure

Info

Publication number: WO2016035506A1
Application number: PCT/JP2015/072429
Authority: WO
Inventors: 明義加藤; 和章北口
Original assignee: 豊田鉄工株式会社
Priority date: 2014-09-03
Filing date: 2015-08-06
Publication date: 2016-03-10
Also published as: JP6177744B2; JP2016052829A

Abstract

The purpose of the present invention is to improve the performance of impact energy absorption of side impact loads. When subjected to a side impact load (F), a left side frame (14) is crushed first, and following the crushing of the left side frame (14), bent portions (22) of cross members (16), which are bent into a crank shape, buckle in a Z-like shape. Through these deformations, excellent impact energy absorption performance is achieved. In particular, since the manner in which the left side frame (14) is crushed and the cross member (16) buckles is different, tuning the deformation strengths thereof would allow the impact energy to be efficiently absorbed in a relatively short deformation stroke.

Description

Body frame structure

The present invention relates to a vehicle body frame structure, and more particularly to a vehicle body frame structure capable of obtaining excellent impact energy absorption performance against a side collision load.

(A) a side frame disposed along the vehicle longitudinal direction at an end in the vehicle width direction; and (b) disposed along the vehicle width direction and abutted against a side surface of the side frame on the vehicle inner side. A vehicle body frame structure having a cross member to be joined is known. The vehicle body frame structure described in Patent Document 1 is an example, and a weak portion is provided in a floor constituent material in a vehicle outer region of a side frame, and the floor constituent material is crushed and deformed at the time of a side collision to absorb impact energy. At the same time, the deformation of the side frame is suppressed.

Japanese Patent Laid-Open No. 7-81625

However, there are cases where sufficient impact energy absorption performance cannot always be obtained simply by providing an impact energy absorbing portion due to crushing deformation in the vehicle outer region of the side frame.

The present invention has been made against the background of the above circumstances, and its object is to improve the impact energy absorption performance against a side collision load.

In order to achieve such an object, the first invention includes (a) a side frame disposed along the vehicle longitudinal direction at an end in the vehicle width direction, and (b) disposed along the vehicle width direction. (C) the side frame has a closed cross-section that is crushed when a side collision load is applied. (D) The cross member has a closed cross-section hollow structure, and an end joined to the side frame is a bent portion bent in a crank shape, and the side collision load is applied. In this case, the bent portion is buckled following the crushing of the side frame.

Here, the crushing of the side frame is a deformation in which the side frame is crushed in a direction substantially perpendicular to the axial direction (vehicle width direction), and the buckling of the bent portion is Z-shaped in the axial direction of the cross member (vehicle width direction). It is a deformation that bends like this.
In addition, the specific mode in which the bent portion is buckled following the collapse of the side frame is not only the case where the bent portion starts to buckle after the side frame is completely collapsed, but at least the side frame is collapsed. The buckling of the bent portion may be started after the start, or the buckling of the bent portion may proceed in parallel from the middle of the side frame collapse.

The second invention is characterized in that, in the vehicle body frame structure of the first invention, the side frame is provided with a weak portion that induces crushing.

A third invention is characterized in that, in the vehicle body frame structure of the first invention or the second invention, a fragile portion for inducing buckling is provided in the bent portion of the cross member.

According to a fourth aspect of the present invention, in the vehicle body frame structure of the third aspect, the weakened portion is provided in a straight portion of an end portion of the crank-shaped bent portion that is joined to the side frame. To do.

A fifth aspect of the invention is the vehicle body frame structure according to any one of the first to fourth aspects of the invention. (A) The vertical dimension of the cross member is smaller than ½ of the vertical dimension of the side frame, The frame and the cross member are disposed so that lower end surfaces thereof are located on substantially the same plane. (B) The bent portion of the cross member is at an intermediate position including a central portion in the vertical direction of the side frame. It is bent in a crank shape upward so as to be joined.

A sixth aspect of the present invention is the vehicle body frame structure according to any one of the first to fifth aspects of the present invention, wherein the bent portion of the cross member includes the side frame and an end portion of a functional component for a vehicle disposed on the cross member. It is provided between.

In such a vehicle body frame structure, when a side collision load is applied, the side frame is first crushed, and following the crushing of the side frame, the bent portion of the cross member bent into a crank shape is seated. Therefore, excellent impact energy absorption performance can be obtained by such deformation. In particular, side frame crushing and cross member buckling are deformed differently so that the impact energy can be efficiently absorbed with a relatively short deformation stroke by adjusting (tuning) their deformation strength. can do.

In the second invention, the side frame is provided with a weak portion that induces crushing, so that the side frame can be appropriately crushed by the side collision load, and its deformation strength (collapse start load) and load-deformation The characteristics can be adjusted by the weak part.

In the third aspect of the invention, since the weak part for inducing buckling is provided in the bent part of the cross member, the cross member can be appropriately buckled by the side collision load in combination with the crank shape, and the deformation strength thereof (Buckling start load) and load-deformation characteristics can be adjusted by the fragile part and the bending angle of the crank shape.

In the fourth aspect of the invention, since the weak portion is provided in the straight portion of the end portion of the crank-shaped bent portion that is joined to the side frame, the impact energy is appropriately absorbed by buckling of the weak portion. At the same time, the deformation stroke is suppressed at the high-strength portion on the inner side of the fragile portion, so that damage to components such as the vehicle functional component is appropriately suppressed.

5th invention is a case where it arrange | positions so that the lower end surface of a side frame and a cross member may be located in the substantially the same plane, and the bending part of a cross member joins to the intermediate position containing the center part of the up-down direction of a side frame. The side frame is properly supported from the inside of the vehicle by the cross member when a side collision load is applied to the side frame. The impact energy absorption performance by can be obtained appropriately. In other words, when the cross member is joined to the lower side portion of the side frame, there is a high possibility that the upper side portion of the side frame tilts so as to enter the inside of the vehicle when a side collision load is applied. The side frame may not be properly crushed and the impact energy absorption performance may be impaired.

In the sixth aspect of the invention, the bent portion of the cross member is provided in a portion between the functional component for a vehicle disposed on the cross member and the side frame, so that when a side collision load is applied, Since the impact energy is absorbed by deformation in a region outside the functional component, the vehicle functional component is prevented from being damaged.

It is a perspective view which shows one Example of this invention. FIG. 2 is an enlarged cross-sectional view taken along the line II-II in FIG. 1, that is, the vicinity of the joint between the side frame and the cross member. FIG. 2 is a cross-sectional view schematically illustrating a deformation mode when a side collision load F is applied in the vehicle body frame structure of FIG. 1. FIG. 2 is a perspective view for explaining a side collision test for examining a load-deformation characteristic by colliding a collision barrier with the vehicle body frame structure of FIG. 1. FIG. 5 is a diagram showing the load-deformation characteristics obtained by the side collision test of FIG. 4 in comparison with a conventional product. It is a figure explaining the conventional product of FIG. 5, and is a perspective view corresponding to FIG. FIG. 7 is an enlarged sectional view taken along the line VII-VII in FIG. 6. It is the schematic which showed the deformation | transformation state in deformation | transformation stroke ST1, ST2 part of FIG. 5 comparing the product of this invention and the conventional product. It is a figure explaining the other Example of this invention, and is sectional drawing corresponding to FIG.

The present invention relates to a vehicle body frame structure of an automobile, and both ends of a cross member are joined to a pair of left and right side frames, and it is desirable to apply the present invention to both the left and right, but it applies to either the left or right You can just do it. Moreover, you may apply only to some cross members of many cross members. Both the side frame and cross member have a hollow structure with a closed cross section, and a rectangular or square rectangular cross section is desirable, and a hollow extruded shape or pipe material made of a metal material is preferably used. A material etc. can also be used. If necessary, reinforcing parts such as ribs and partition plates can be provided inside the hollow structure. Reinforcing portions such as ribs and flanges can be provided outside the hollow structure. These side frames and cross members are disposed on a substantially horizontal floor panel, for example, but may be disposed separately from the floor panel. In general, a plurality of cross members are arranged at a predetermined interval in the vehicle front-rear direction, but only a single cross member may be provided.

In the side frame, for example, uneven parts such as irregular beads, holes, grooves, and notches are provided in the longitudinal direction, that is, in the longitudinal direction of the vehicle so that the cross member can be crushed before buckling of the cross member. When a side collision load is applied while maintaining the strength in the longitudinal direction of the vehicle, it is easily crushed in the width direction of the vehicle, but the wall thickness of the side wall is reduced over the entire circumference, or a relatively fragile material is used. It is also possible to make it easy to collapse. The cross member is provided with a crank-shaped bent portion that can be buckled following the crushing of the side frame. The bent portion is also provided with a weak portion such as a notch or a groove as necessary. When the cross member is manufactured by three-dimensional hot bending quenching, for example, the region other than the bent portion is hardened to increase the strength, but the whole or part of the bent portion is not quenched. In this way, it can be a relatively weak part. By strengthening by quenching, impact energy is appropriately absorbed by buckling of the bent portion, and the vehicle functional parts such as a generator disposed inside the vehicle from the bent portion are appropriately protected. be able to. 3D hot bending and quenching is a processing technology in which hollow steel materials such as pipes are locally heated and bent, and quenched by quenching with water, etc., and quenching is performed by controlling the heating and quenching sites. The range can be adjusted.

The crank-shaped bent portion is bent upward in a crank shape so as to be joined to an intermediate position including the central portion in the vertical direction of the side frame, for example, as in the fifth invention. Various modes are possible, such as being able to be bent in a crank shape or being bent in a crank shape in the longitudinal direction of the vehicle. By providing a crank-shaped bent portion, it becomes easy to buckle and deform into a Z-shape when a load is applied from the axial direction of the cross member, that is, from the side frame side. It may be a crank shape with a relatively large obtuse angle and a gentle bending angle. The deformation strength when the bent portion is buckled can be adjusted depending on the bending angle or the presence or absence of a fragile portion, etc., but the deformation strength of the bent portion is such that the bent portion is buckled following the collapse of the side frame. The deformation strength of the side frame is substantially the same as or higher than that. In the fifth aspect of the invention, the vertical dimension of the cross member is smaller than ½ of the vertical dimension of the side frame, but may be ½ or more of the vertical dimension of the side frame in implementing other inventions. Various aspects are possible.

The vehicle functional parts of the sixth invention are various parts originally mounted on the vehicle and exhibiting a predetermined function, such as an engine, an electric motor, a generator, a battery, a battery case, and a transmission. The generator is, for example, a motor generator of a hybrid vehicle having an engine and an electric motor as driving force sources. In implementing other inventions, the vehicle functional component and the bent portion may overlap in the vehicle width direction. The present invention can be applied to a body frame structure of various vehicles such as an engine-driven vehicle having only an engine as a driving force source.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the dimension of each part in the following Examples, a dimension ratio, an angle, a wall thickness, etc. are not necessarily represented correctly.

FIG. 1 is a schematic perspective view of a vehicle body frame structure 10 according to an embodiment of the present invention, showing a left half, and a right half (not shown) is also configured symmetrically. The vehicle body frame structure 10 is arranged on the left end portion of the substantially horizontal floor panel 12 along the vehicle front-rear direction, and on the floor panel 12 along the vehicle width direction. And a longitudinal cross member 16 provided, both of which are integrally welded to the floor panel 12. A plurality of cross members 16 are disposed apart from each other in the vehicle front-rear direction, and the left end portion of the cross members 16 abuts on the side surface on the vehicle inner side of the left side frame 14 so as to be integrally joined by welding. .

FIG. 2 is an enlarged cross-sectional view taken along the line II-II in FIG. 1, that is, the vicinity of the joint between the left side frame 14 and the cross member 16. As is apparent from FIG. 2, the left side frame 14 has a hollow structure with a rectangular closed cross section, and is composed of a hollow extruded shape member or pipe material made of a metal material, and the rectangular closed cross section is vertically It is arranged on the floor panel 12 in a vertically long posture in the direction. On substantially horizontal side walls positioned above and below the left side frame 14, beads 18 that are recessed inwardly in a U-shaped or V-shaped cross section are provided in the longitudinal direction, that is, in the longitudinal direction of the vehicle. The side collision load F is applied by the collision barrier 20 as shown in (a) “side collision load input” and (b) “side frame collapse (collapse)” in FIG. In this case, the left side frame 14 is easily crushed in the vehicle width direction starting from the bead 18. The bead 18 corresponds to a fragile portion that induces the left side frame 14 to be crushed in the vehicle width direction and to be crushed during a side collision.

The cross member 16 has a hollow structure with a rectangular closed cross section, and is composed of a hollow extruded shape member or pipe material made of a metal material, and the rectangular closed cross section is a horizontally long posture in the vehicle longitudinal direction. Arranged on the panel 12. The vertical dimension of the cross member 16 is about 1/4 that is sufficiently smaller than 1/2 of the vertical dimension of the left side frame 14. A bent portion 22 bent in a crank shape is provided so as to be spaced apart from each other, and is joined to an intermediate position including the central portion C in the vertical direction of the left side frame 14. When the side collision load F is applied, the bent portion 22 is formed by the cross member 16 following the crushing of the left side frame 14 as shown in (c) “Cross member buckling (Z folding)” in FIG. In order to be able to buckle in a Z-shape in the axial direction, in this embodiment, the two bending angles are formed into a gentle crank shape with a relatively large obtuse angle, and a predetermined deformation strength, that is, impact energy absorption performance. Can be obtained. In addition, the cross member 16 is manufactured by three-dimensional hot bending quenching and is strengthened by quenching. However, the straight portion of the end portion on the side joined to the left side frame 14 in the crank-shaped bent portion 22 is used. The fragile portion 22a is provided with a relatively fragile portion so as not to be quenched, and the fragile portion 22a is buckled in the axial direction following the collapse of the left side frame 14, and the bent portion 22 is Buckled in a Z shape. The deformation strength of the bent portion 22 including the buckling of the fragile portion 22a can be adjusted by the bending angle of the crank shape, the range of the fragile portion 22a, etc., so that it can be buckled following the collapse of the left side frame 14, It is higher than the deformation strength when the left side frame 14 is crushed.

The bent portion 22 is provided at a portion of the vehicle functional component that is disposed on the cross member 16 so as to protrude outward from the generator 24 in the vehicle width direction. While absorbing, it is possible to appropriately protect the generator 24 disposed in the intermediate region of the cross member 16 that has been strengthened by quenching. The generator 24 is a motor generator having functions of both a generator and an electric motor, for example, and the vehicle body frame structure 10 of this embodiment is used for a hybrid vehicle or an electric vehicle having a motor generator as a vehicle functional component. .

Here, as shown in FIG. 4, a side collision test is performed in which a collision barrier 20 having a semicircular tip is collided from the side substantially perpendicular to the left side frame 14, and the body frame structure 10 is analyzed by FEM analysis. The results of examining the load-deformation characteristics will be described. For comparison, in addition to the product of the present invention (body frame structure 10), the conventional body frame structure 30 shown in FIGS. 6 and 7 was also tested under the same conditions. The left side frame 32 of the vehicle body frame structure 30 is the same as that of the present invention in that it has a hollow structure with a rectangular closed cross section, but the bead 18 is not provided. Further, the cross member 34 has a hat cross-sectional shape in which a flange extends outward from both ends of the dish-shaped (shallow U-shaped) opening side, and the flange is in contact with the floor panel 12 in the longitudinal direction. It is fixed to the floor panel 12 over its entire length, its end is abutted against the lower end portion of the left side frame 32 and welded, and a reinforcing stay 36 is placed on the upper corner of the end on the left. It is fixed across the side frame 32 and the cross member 34.

FIG. 5 is a diagram comparing the load-deformation characteristics of the product of the present invention and the conventional product. In the product of the present invention, the bent portion 22 of the cross member 16 is buckled following the collapse of the left side frame 14. As a result, the load is stably maintained at a high level, and excellent impact energy absorption performance can be obtained. The integrated value of the load in the load-deformation characteristic graph shown in FIG. 5 corresponds to the absorbed energy. In contrast, the conventional product can accept a high load at the initial stage of deformation, but as the deformation stroke increases, the load decreases rapidly and the deformation proceeds easily, and sufficient impact energy absorption performance is achieved. I can't get it.

FIG. 8 is a schematic view showing the deformation state in the deformation strokes ST1 and ST2 of FIG. 5 in comparison with the product of the present invention and the conventional product. In the product of the present invention, the collapse of the left side frame 14 and the cross member 16 are shown. Deformation proceeds while maintaining a high load level due to buckling (Z-bending). In contrast, the conventional product can obtain a high load until the end of the cross member 34 is bent without the left side frame 32 being crushed, but the load is applied when the end of the cross member 34 is bent near the deformation stroke ST1. Decreases rapidly. Further, in the conventional product, since the cross member 34 is joined to the lower side portion of the left side frame 32, the upper portion of the left side frame 32 is accompanied by the bending of the cross member 34 regardless of the presence of the reinforcing stay 36. Is tilted so as to enter the inside of the vehicle, and in the vicinity of the deformation stroke ST2, the load is further reduced, and impact energy absorption performance is hardly obtained. In the product of the present invention, the bent portion 22 of the cross member 16 is bent upward in a crank shape and joined to an intermediate position including the central portion C of the left side frame 14 in the vertical direction. The side frame 14 is appropriately supported from the inside of the vehicle, and the left side frame 14 is appropriately crushed to absorb impact energy.

As described above, in the vehicle body frame structure 10 of the present embodiment, when the side collision load F is applied, the left side frame 14 is first crushed, and following the collapse of the left side frame 14, Since the bent portion 22 of the cross member 16 bent in the shape of the cross member 16 is buckled in a Z-shape, excellent impact energy absorption performance can be obtained by such deformation. In particular, the deformation of the left side frame 14 and the buckling of the cross member 16 are different in deformation form. Therefore, by adjusting (tuning) the deformation strength, the impact energy is efficiently absorbed with a relatively short deformation stroke. become able to.

Further, since the left side frame 14 is provided with a bead 18 as a weak portion that induces crushing, the left side frame 14 can be appropriately crushed by the side collision load F and its deformation strength (crushing) The starting load) and load-deformation characteristics can be adjusted by the depth and width of the bead 18.

Further, since the bending portion 22 of the cross member 16 is provided with a weak portion 22a that induces buckling by being relatively low strength without quenching, the cross member 16 is coupled with the crank shape so that the side member is subjected to a side collision load. It becomes possible to buckle appropriately by F, and its deformation strength (buckling start load) and load-deformation characteristics can be adjusted by the range of the fragile portion 22a, the bending angle of the crank shape, and the like.

Moreover, since the linear part of the edge part joined to the left side frame 14 among the crank-shaped bending parts 22 is made into the weak part 22a, impact energy is absorbed appropriately by buckling of the weak part 22a. In addition, damage to the generator 24 is appropriately suppressed by suppressing the deformation stroke at the high-strength portion inside the fragile portion 22a.

In the present embodiment, the left side frame 14 and the cross member 16 are disposed on the common floor panel 12, but the bent portion 22 of the cross member 16 includes the center C in the vertical direction of the left side frame 14. Since it is bent upward in a crank shape so as to be joined to the intermediate position, when the side collision load F is applied to the left side frame 14, the left side frame 14 is appropriately secured from the inside of the vehicle by the cross member 16. As a result, the impact energy absorbing performance by the crushing of the left side frame 14 is appropriately obtained.

Further, the bent portion 22 of the cross member 16 is provided at a portion between the generator 24 and the left side frame 14 that are functional parts for the vehicle, that is, a portion protruding from the generator 24 to the outside in the vehicle width direction. When the side impact load F is applied, the generator 24 is prevented from being damaged by being deformed in the region outside the generator 24 and absorbing the impact energy. In particular, since the cross member 16 of this embodiment is manufactured by three-dimensional hot bending quenching and is hardened except for both ends, the impact energy is appropriately adjusted by buckling of the bent portion 22. The generator 24 disposed in the middle region of the cross member 16 that has been strengthened by quenching can be appropriately protected.

In the above embodiment, the entire area of the straight portion at the end joined to the left side frame 14 in the crank-shaped bent portion 22 is the weakened portion 22a without quenching, but as shown in FIG. Further, the weakened portion 22a without quenching may be provided intermittently alternately with the high strength portion with quenching.

As mentioned above, although the Example of this invention was described in detail based on drawing, these are one embodiment to the last, and this invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.

10: Body frame structure 14: Left side frame (side frame) 16: Cross member 18: Bead (fragile part) 22: Bending part 22a: Fragile part 24: Generator (functional part for vehicle) F: Side impact load C: Center

Claims

A side frame disposed along the vehicle longitudinal direction at an end in the vehicle width direction;
A cross member that is disposed along the vehicle width direction and is abutted against and joined to a side surface of the side frame on the vehicle inner side;
Body frame structure having
The side frame is a closed cross-section hollow structure that is crushed when a side collision load is applied,
The cross member has a hollow structure with a closed cross section, and an end joined to the side frame is a bent portion bent in a crank shape, and when the side collision load is applied, the side frame A vehicle body frame structure characterized in that the bent portion is buckled following crushing.
The vehicle body frame structure according to claim 1, wherein the side frame is provided with a weak portion that induces crushing.
The vehicle body frame structure according to claim 1, wherein a weakened portion that induces buckling is provided in the bent portion of the cross member.
4. The vehicle body frame structure according to claim 3, wherein the fragile portion is provided in a straight portion of an end portion of the crank-shaped bent portion that is joined to the side frame.
The vertical dimension of the cross member is smaller than ½ of the vertical dimension of the side frame, and the side frame and the cross member are disposed so that the lower end surfaces thereof are located on substantially the same plane,
The bent portion of the cross member is bent upward in a crank shape so as to be joined to an intermediate position including a central portion in the vertical direction of the side frame. The vehicle body frame structure according to item 1.
The bent portion of the cross member is provided between the side frame and an end portion of a vehicle functional component disposed on the cross member. The vehicle body frame structure described in the paragraph.