JP6089993B2 - Shock absorbing member - Google Patents

Description

  The present invention relates to an impact absorbing member for an automobile body that absorbs collision energy at the time of automobile collision.

  In order to secure a living space in the passenger compartment in the event of a car crash, an impact absorbing member that absorbs the collision energy at the time of collision is attached to the body of the car while collapsing in the axial direction.

  For example, Patent Document 1 discloses an impact absorbing member that is buckled and deformed in a stable state to increase the amount of energy absorbed during a collision. The shock absorbing member is interposed between a straight tube portion having a substantially constant inner diameter, a tapered tube portion formed in a tapered shape, and the other end portion of the straight tube portion and the tapered tube portion. Both have the intermediate cylinder part connected on the same axis.

JP 2011-11661 A

  However, the impact absorbing member described in Patent Document 1 must be manufactured by welding a plurality of members. Therefore, there is a problem that the structure is complicated and the manufacturing cost increases. In addition, since the shock absorbing member described in Patent Document 1 starts to be crushed from the intermediate tube portion, the start of the crushing of the tapered tube portion attached to the tip side of the intermediate tube portion is the crushing process of the shock absorbing member. The impact energy absorbed is reduced accordingly.

  An object of the present invention is to solve such a problem of the prior art, and an impact absorbing member having an increased amount of impact energy absorbed by stably collapsing in the axial direction over the entire impact absorbing member. It is intended to provide.

In order to achieve the above-mentioned object, according to the present invention, in an automobile impact absorbing member that receives impact energy from a tip and is crushed in the axial direction, the impact absorbing member is coupled to a vehicle body portion that forms an automobile cabin. The first member having the same moment of inertia and the same maximum buckling strength in an arbitrary vertical cross section from 47 to 50% of the total length in the length direction from the base end portion to be continuously formed with the first member connecting, and said proximal portion a hollow columnar member made of a second member having a distal portion for receiving the impact load on the opposite side, cross a vertical direction in the front end portion of the second member, said A cross section when a vertical cross section b at the base end portion of one member and an arbitrary vertical cross section of the second member between the distal end portion and a portion where the first member and the second member are connected are defined as a cross section ci. The second moment M is Ma <Mci and Ma <0. Has a relationship of 80 Mb, further, the maximum buckling force F Fa <Fci, and the shock absorbing member characterized by having a relationship of Fa <0.85Fb is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the impact-absorbing member which can be crushed over the whole impact-absorbing member while buckling stably from a front-end | tip part is provided.

1 is a schematic view of an impact absorbing member according to a first embodiment. 3 is a schematic view of an impact absorbing member according to a second embodiment. It is a graph which shows the section moment of inertia of the shock absorption member used by simulation. It is a graph which shows the maximum buckling strength of the impact-absorbing member used by simulation. FIG. 5 is a schematic diagram showing positions where the horizontal axis coordinates of the graph of the sectional moment of inertia and the maximum buckling strength graph shown in FIGS. It is a figure which shows the simulation result which calculated | required the start of the crushing process when the impact load was given from the front-end | tip of the impact-absorbing member which has the cross-sectional secondary moment and the maximum buckling proof shown in FIG. It is the same graph as FIG. 4 which shows the cross-sectional secondary moment of the impact-absorbing member used by the further simulation. It is the same graph as FIG. 5 which shows the maximum buckling proof stress of the impact-absorbing member used by the further simulation. It is a figure which shows the simulation result which calculated | required the crushing process of the impact-absorbing member which does not satisfy | fill the requirements of this invention by numerical analysis. It is a figure which shows the simulation result which calculated | required the crushing process of the impact-absorbing member by this invention by numerical analysis. It is a graph which shows the change of the reaction force with respect to the displacement of the impact-absorbing member in a crushing process. It is a graph which shows the change of the energy amount absorbed with respect to the displacement of the impact-absorbing member in a crushing process.

A preferred embodiment of the present invention will be described below with reference to FIGS.
A shock absorbing member 10 according to the first embodiment shown in FIG. 1 is a quadrangular prism-shaped member, and includes a first member having a base end portion 10b welded to a vehicle body 100 forming a passenger compartment of an automobile, and a base end portion 10b. And a second member having a tip portion 10a on the opposite side. In particular, in FIG. 1, the shock absorbing member 10 is directly coupled to the front edge portion of the vehicle body 100 forming the passenger compartment of the automobile at the base end portion 10b. In the frontal collision of the automobile, the impact absorbing member 10 starts to be crushed from the tip portion 10a, and the crushing process proceeds stably in the axial direction. The shock absorbing member 10 may be coupled to the rear edge of the vehicle body 100.

The impact absorbing member 20 according to the second embodiment shown in FIG. 2 is also a quadrangular prism-like member. In this embodiment, the impact absorbing member 20 is a vehicle body 100 that forms a passenger compartment of an automobile, particularly the front edge of the vehicle body 100. The base member 24 welded to the vehicle part and the intermediate member 22 extending obliquely in the width direction of the automobile are offset inward in the width direction of the automobile and coupled to the vehicle body 100 forming the passenger compartment of the automobile Has been. The shock absorbing member 20 includes a first member having a base end portion 20b welded to the intermediate member 22, and a second member having a tip end portion 20a opposite to the base end portion 20b. At the time of a frontal collision of the automobile, the impact absorbing member 20 starts to be crushed from the front end portion 20a, and the crushing process proceeds stably in the axial direction. The shock absorbing member 20 may be coupled to the rear edge of the vehicle body 100.

According to the present invention, the impact absorbing members 10 and 20 according to the first and second embodiments have the same moment of inertia in an arbitrary vertical cross section from 47 to 50% of the total length in the length direction from the base end. And a first member having the same maximum buckling strength, and a second member having distal end portions 10a and 20a that are continuously connected to the first member and form a collision end opposite to the base end portion. A hollow columnar member comprising a vertical section a at the distal end of the second member , a vertical section b at the proximal ends 10b and 20b of the first member , the distal sections 10a and 20a , When the arbitrary cross section of the second member between the first member and the second member is defined as the cross section ci, the cross sectional secondary moment M has a relationship of Ma <Mci and Ma <0.80 Mb. Furthermore, the maximum buckling strength F has a relationship of Fa <Fci and Fa <0.85Fb. The

Hereinafter, simulation (numerical analysis) results of various impact absorbing members in which the cross-sectional secondary moment and the maximum buckling strength are changed will be described.
First, the crushing behavior was simulated for the four shock absorbing members T0, T1, T3, and T4. The sectional moment of inertia and the maximum buckling strength of the four shock absorbing members T0, T1, T3, and T4 are as shown in FIGS. FIG. 5 shows a position where the horizontal axis coordinates of the graph of the sectional moment of inertia and the maximum buckling strength graph shown in FIGS.

  Referring to FIG. 6, which is a simulation result, the crush start position when an impact load is applied to the tip portions of the four impact absorbing members T0, T1, T3, and T4 is apparent. It will be understood from FIG. 6 that the impact absorbing members T1 and T3 that satisfy the conditions of the present invention start crushing from the tip.

  Furthermore, the crushing behavior was simulated for the two shock absorbing members T6 and T7. The cross-sectional secondary moments and the maximum buckling strength of the four shock absorbing members T6 and T7 are as shown in FIGS. The coordinates of the horizontal axis of the graph of the sectional moment of inertia and the maximum buckling strength shown in FIGS. 7 and 8 are as shown in FIG.

  9 and 10, which are simulation results, show the crushing process when an impact load is applied to the tip of each of the two shock absorbing members T6 and T7. 9 and 10, the impact absorbing member T6 that does not satisfy the conditions of the present invention starts crushing from the tip portion, but is buckled obliquely, resulting in an unstable crushing process. It will be understood that the shock absorbing member T7 that satisfies the above condition is buckled evenly in the circumferential direction from the tip, and is a stable crushing process.

  FIG. 11 shows the change in the reaction force with respect to the displacement during the crushing process, and FIG. 12 shows the change in the amount of impact energy absorbed. From FIG. 11, in the impact absorbing member T7 exhibiting a stable crushing process, the reaction force increases as the crushing process proceeds. However, in the shock absorbing member T6 in which the crushing process is unstable, the base of the shock absorbing member T6 is shown. It will be appreciated that the reaction force has fallen sharply since the end begins to buckle. Also, from FIG. 12, the shock absorbing members T6 and T7 absorb the shock absorbing energy in the same way until the middle of the crushing process, but are also absorbed from the time when the base end of the shock absorbing member T6 starts to buckle. It will be understood that the amount of impact energy is low.

Further, Table 1 is a table showing whether or not sufficient impact energy can be absorbed for a plurality of impact absorbing members N0 to N9 in which the sectional moment of inertia and the maximum buckling load are changed in the longitudinal direction. is there. Table 1 shows the cross-sectional secondary moment and the maximum buckling load when the distance from the base end of the shock absorbing member is 0 mm (base end), 310 mm, 460 mm, and 660 mm. It is shown as a ratio to the load. In Table 1, ◯ indicates an impact absorbing member that starts deformation from the tip (collision end) where a sufficient amount of energy absorption can be confirmed, and × indicates sufficient energy that is deformed from other than the tip (collision end). An impact absorbing member whose absorption amount could not be secured is shown.

  From Table 1, it will be understood that according to the present invention, the impact absorbing member can absorb higher impact absorbing energy than the impact absorbing member that is not.

  The present invention can be used for an impact absorbing member of an automobile.

DESCRIPTION OF SYMBOLS 10 Shock absorption member 10a Tip part 10b Base end part 20 Shock absorption member 20a Tip part 20b Base end part 100 Car body

Claims (4)

In the impact absorbing member of an automobile that receives impact energy from the tip and collapses in the axial direction,
The shock absorbing member has the same moment of inertia and the same maximum buckling in an arbitrary vertical section up to 47 to 50% of the total length in the longitudinal direction from the base end portion coupled to the vehicle body part forming the passenger compartment of the automobile. A hollow columnar member composed of a first member having a proof stress and a second member having a distal end portion that receives an impact load opposite to the base end portion and is continuously connected to the first member ,
A vertical section a at the distal end of the second member , a vertical section b at the proximal end of the first member, and between the distal end and the portion where the first member and the second member are connected . When an arbitrary vertical cross section of the second member is a cross section ci, the cross sectional secondary moment M has a relationship of Ma <Mci and Ma <0.80 Mb, and the maximum buckling strength F is Fa <Fci. And the impact-absorbing member characterized by having the relationship of Fa <0.85Fb.   2. The impact absorbing member according to claim 1, wherein the impact absorbing member is directly coupled to a front edge portion of a vehicle body part forming a passenger compartment of an automobile at a base end portion thereof.   The shock absorbing member is formed on the inner side in the width direction of the automobile through a base member coupled to a front edge portion of a vehicle body part forming a passenger compartment of the automobile and an intermediate member extending obliquely in the width direction of the automobile. The impact-absorbing member according to claim 1, wherein the impact-absorbing member is offset.   The impact absorbing member according to claim 1, wherein the impact absorbing member is a prism.