JP4039032B2 - Impact energy absorbing member - Google Patents

Description

【００２３】
【発明の効果】
本発明によれば、容易にかつ低コストで自動車衝突時のエネルギー吸収能が高い部材を製造することが可能であり、乗員の安全はもとより、車両の軽量化を図ることができるという優れた効果を奏する。
【図面の簡単な説明】
【図１】第１の発明部材の例を示す断面図である。
【図２】第２の発明部材の例を示す断面図である。
【図３】端部に他部材等接続用フランジを設けた本発明部材の例を示す模式図である。
【図４】第３の発明部材の例を示す側面図である。
【図５】第４の発明部材の例を示す側面図である。
【図６】フロントサイドフレームへの衝突荷重のかかり方を示す説明図である。
【図７】部材Ａ〜Ｄのエネルギー吸収量比を示すグラフである。
【図８】部材Ｅ〜Ｇのエネルギー吸収量比を示すグラフである。
【符号の説明】
１，１ａ，10 円管
２，２ａ 角管
３ フランジ
４ あて板
11，11ａ 第１の発明部材
20 フロントサイドフレーム
21 バンパ
22 衝突荷重（エネルギー）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a collision energy absorbing member, and more particularly, to a collision energy absorbing member that absorbs collision energy at the time of automobile collision among metal automobile body frame structural members.
[0002]
[Prior art]
Among the frame structural parts of an automobile body, a front side frame as shown in FIG. 6 and a rear side frame arranged at the rear of the vehicle have an important role as an energy absorbing member at the time of automobile collision. When an automobile collides, the front or rear side frames are structured so as to absorb the energy at the time of collision by appropriately collapsing into a bellows shape and to secure a passenger living space in the cabin. It is common. For example, in the front side frame 20 shown in FIG. 6, a collision load (energy) 22 input at the time of a collision in the front is transmitted to the front side frame 20 via the bumper 21, and at this time, the front side frame is appropriately If the crushing energy cannot be absorbed, the collision load is further transmitted to the rear cabin, causing damage to the passenger.
[0003]
Under such a background, a member having high energy absorption capability is demanded for a collision energy absorbing member such as a front side frame.
In response to such a request, for example, in Japanese Patent Laid-Open No. 4-310477, a basic member extruded into a closed cross-sectional structure with a light metal is fitted into the basic member and compressed to at least the tip of the same length. A member in which a double structure is formed with a reinforcing member provided with a deformation promoting portion, preferably a notch, has been proposed. In addition, in JP-A-11-29064 and JP-A-11-208519, ribs connected to the inner surface of the hollow material are provided on the surface passing through the central axis of the hollow material by extrusion processing of the light metal material. A frame structure of an automobile body characterized by this is proposed.
[0004]
All of these conventional techniques are for producing extruded parts of light metal materials typified by aluminum, so that the problem is that the parts themselves are expensive and the connecting method with adjacent parts is complicated. There was a problem.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a collision energy absorbing member for automobiles that is small and light, has a large amount of shock absorption energy, is inexpensive and has excellent productivity.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors considered as follows.
In order to increase the energy absorption amount at the time of collision, it is effective to increase the thickness of the material constituting the member. However, increasing the thickness of the component directly increases the weight of the vehicle body and directly leads to a deterioration in fuel consumption. From the viewpoint of global environmental conservation, CO ₂ emission reduction activities that are being deployed globally, that is, This is not preferable from the viewpoint of reducing the weight of the automobile.
[0007]
As another method for increasing the energy absorption amount, there is a method for optimizing the cross-sectional shape of the member. The optimization of the cross-sectional shape follows the trend of reducing the weight of automobiles in that the amount of energy absorption per unit weight of the member is increased without increasing the thickness of the member.
A member having a closed section structure having a partition wall formed by extrusion processing, such as a front side member by extrusion processing of a light metal material typified by aluminum according to the conventional proposal, has a simple closed section structure without the partition wall. Compared with the member, there is an advantage that the amount of energy absorption increases and the buckling shape is stabilized, whereby the amount of energy absorption and the buckling load during deformation are also stabilized. However, the extrusion processing of aluminum materials has a problem that the material and manufacturing cost are high and productivity is poor.
[0008]
In addition, using a steel material (for example, a thin steel plate) most commonly used as a frame material for an automobile body, it is possible to manufacture a closed cross-section structural member having a partition wall by a known method (for example, sheet metal processing). Although it is possible, there are problems in terms of manufacturing technology and cost because the processing is complicated and many steps are required.
Therefore, the present inventors have repeatedly studied to solve these problems, and as a result, metal hollow members, particularly circular tubes (metal tubes having a circular cross-sectional shape), square tubes (metal having a cross-sectional shape of a polygon). It has been found that a closed cross-section structural member having an internal partition wall that can be easily and inexpensively manufactured by combining pipes in a nested manner, and has led to the present invention described below.
[0009]
(1) In a collision energy absorbing member that absorbs collision energy at the time of automobile collision by axial buckling of a metallic pipe member among metallic automobile body frame structural members, the metallic pipe material is inserted into the outer pipe and the outer pipe. The inner pipe is fixed to the outer pipe by welding or press fitting, and is used as the outer pipe.
(1-1) A circular tube and / or a square tube as a plurality of inner tubes inscribed in the circular tube, or
(1-2) One or more circular tubes and / or square tubes that are in contact with the inside of the circular tube over its entire length,
A collision energy absorbing member having a closed cross-sectional shape formed with a partition wall (first invention member).
(2) In a collision energy absorbing member that absorbs collision energy at the time of automobile collision by axial buckling of the metal pipe material among metal automobile body frame structural members, the metal pipe material is inserted into the outer tube and the outer tube. The inner pipe is fixed to the outer pipe by welding or press fitting, and is used as the outer pipe.
(2-1) A circular tube and / or a square tube as a plurality of inner tubes inscribed in the square tube, or
(2-2) One or more circular tubes and / or square tubes that are in contact with the inside of the square tube over its entire length,
A collision energy absorbing member having a closed cross-sectional shape having a partition wall (second invention member).
[0010]
(3) In the collision energy absorbing member that absorbs the collision energy at the time of the automobile collision by axial buckling of the metal pipe member among the metal automobile body frame structural members, the closed cross-sectional shape according to (1) or (2) A collision energy absorbing member (a third invention member), characterized in that a member having a shape and a circular tube or a square tube are connected in the tube axis direction.
(4) A collision energy absorbing member that absorbs collision energy at the time of automobile collision by axial buckling of a metal pipe member among metal automobile body frame structural members, wherein the closed cross-sectional shape according to (1) or (2) A collision energy absorbing member (: Fourth invention member), wherein a plurality of members having a plurality of members are connected to each other in the tube axis direction.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a cross-sectional view showing an example of a first invention member. In this figure, (a) shows three circular tubes 1a inserted in the inside of a circular tube 1 as an outer tube (meaning of a hollow portion, the same applies hereinafter), and (b) shows four inserted. Further, a square tube 2a may be inserted into the circular tube 1 as shown in (c) and (e), or a combination of the square tube 2a and the circular tube 1a is inserted as shown in (d). May be. Thereby, since the partition which consists of the tube wall of the circular tube 1a and / or the square tube 1a is formed in the inside of the circular tube 1, it has a partition easily, without using the conventional extrusion process and a complicated processing method. A member having a closed cross-sectional shape can be manufactured. Since this member has a closed cross-sectional shape with a partition formed inside, in addition to its high impact energy absorption capability, it has a high lateral bending rigidity, and therefore, when a collision load is input, the Euler seat extends laterally. It has the advantage that it does not easily buckle and buckles stably in the axial direction.
[0012]
The circular tube or the square tube inserted into the outer tube may be welded to the outer tube by laser welding or the like, or may be fixed by press-fitting.
Next, FIG. 2 is a sectional view showing an example of the second invention member. In the first invention member, a square tube 2 is used instead of the circular tube 1 as an outer tube. Like the first invention member, a large amount of energy is absorbed at the time of collision and stable in the axial direction. Buckle.
[0013]
The present invention member (first to fourth invention members) does not depend on the number of tubes used or the combination of shape types (: circular tube, square tube), but is a combination other than the illustrated ones. However, the same effect can be expected if it has a closed cross-sectional shape with a partition formed inside. The number of tubes to be used and the combination of shape types (circular tube, square tube) may be determined in consideration of the required amount of energy absorption and the weight of the member. The square tube is preferably square in cross-sectional shape from the viewpoint of ease of manufacture, but is not limited thereto.
[0014]
In addition, the member of the present invention can facilitate connection (welding or bolt fastening) to other frame parts or the vehicle body by providing a flange 3 at the end, as illustrated for the first invention member in FIG. . This flange is preferably formed in advance at the end of the outer tube before the circular tube or square tube is inserted.
On the other hand, as one of the ideas for energy absorption at the time of automobile collision, there is an idea of controlling a portion to be buckled (a portion that absorbs energy) according to the degree of collision. The main point of this idea is, for example, in the case of the front side frame of FIG. 6, in the case of a collision at low speed, only the tip (vehicle front side) portion of the member is actively crushed to absorb energy, and the engine behind it Protects the room and reduces the cost of repairs as much as possible. In the case of a high-speed collision, the entire member is crushed to absorb a large amount of collision energy, and only the portion connected to the cabin is solid and the occupant's survival. In order to realize this, it is necessary to control the position of the portion to be crushed in the member in accordance with the collision speed (energy at the time of collision).
[0015]
The third and fourth invention members are provided as members suitable for performing the crushing site control in such a member.
FIG. 4 is a side view showing an example of the third invention member, and this example shows the first invention member 11 having the form shown in FIG. A circular tube 10 having no partition wall (and therefore relatively low strength) is used as a connecting element member, and these are connected in the tube axis direction. The first invention member 11 and the circular pipe 10 were connected by applying flanges 3 provided at their respective end portions to each other via a plate 4 and welding or bolting. In the arrangement in the vehicle, the circular tube 10 was set to the vehicle front end side (bumper side).
[0016]
According to this, when the input speed of the collision load 22 is relatively low, the relatively low-strength portion composed of the circular tube 10 disposed on the bumper side is preferentially crushed, and the subsequent first invention member 11 can protect the engine room without deformation. When the input speed of the collision load 22 is relatively high, the subsequent portion of the first invention member 11 is also crushed, and this portion can absorb a large amount of collision energy, thereby suppressing the deformation of the cabin.
[0017]
FIG. 5 is a side view showing an example of the fourth invention member. This example shows the first invention member 11 in the form shown in FIG. 1A (the number of internally inserted tubes: 3). The first invention member 11a in the form shown in FIG. 1B (the number of internally inserted tubes: 4) is used as a connecting element member, and these are connected in the tube axis direction. The first invention members 11 and 11a were connected to each other by welding the flanges 3 provided at the respective end portions to each other via the plate 4 or by bolting. In the arrangement in the vehicle, the portion of the first invention member 11 having a small number of internal insertion tubes (and therefore relatively low strength) was set as the vehicle front end side (bumper side). Also with this fourth invention member, the crushing part control according to the degree of collision is possible, as with the third invention member. In the fourth invention member, the energy absorption amount of each part in the member can be finely adjusted by changing the number of the internal insertion tubes, the thickness, the material strength, and the like.
[0018]
【Example】
Example 1
Members A to D shown in FIG. 7 were produced. The material of the steel pipe used was a hot-rolled steel sheet with a plate thickness of 1.2 mm and a tensile strength of 440 MPa. The length of each fabricated member in the direction of collision load input was 300 mm. Member A is a comparative example which is a circular tube having a diameter of 100 mm and does not have an internal partition. The members B to D are examples of the present invention having a closed cross-sectional shape in which one or a plurality of other circular tubes or square tubes are inserted into a circular tube as an outer tube, and an internal partition is formed by these inserted tubes (first invention) Examples of members). The insertion tube is inserted by press fitting and is not welded to the outer tube. The circumferences of the outer tube and the insertion tube forming the members B to D were set so that the same weight as that of the member A was obtained.
[0019]
About these members, the weight was made to collide at a speed of 50 km / h, the load generated at the time of collision was measured with a load cell, the displacement of the end of the member hit directly by the weight was measured with a laser displacement meter, and the obtained load − The amount of energy absorbed until the deformation reached 150 mm was calculated by integrating the load with the displacement using the displacement curve. FIG. 7 shows the energy absorption amount ratio of the members A to D (: relative value to the member A). It can be seen that the energy absorption amount increases in the order of A <B <C <D, and the energy absorption capacity of the first invention member is high.
(Example 2)
Members E to G shown in FIG. 8 were produced. The steel pipe material used and the length of each produced member in the collision load input direction were the same as those in Example 1. The member E is a comparative example having a square cross section with a side of 100 mm and having no internal partition. The members F and G are examples of the present invention having a closed cross-sectional shape in which one or a plurality of circular tubes are inserted into a square tube having a square cross section as an outer tube, and an internal partition is formed by these inserted tubes (second invention member) Example). The insertion tube is inserted by press fitting and is not welded to the outer tube. The circumferences of the outer tube and the insertion tube forming the members F and G were set so as to obtain the same weight as the member E.
[0020]
For these members, the amount of energy absorbed until the deformation reached 150 mm was calculated in the same manner as in Example 1.
FIG. 8 shows the energy absorption amount ratio (: relative value to the member E) of the members E to G. It can be seen that the energy absorption amount increases in the order of E <F <G, and the energy absorption capacity of the second invention member is high.
(Example 3)
A connecting member corresponding to the third or fourth invention member was produced under the member combination conditions shown in Table 1. The material of the steel pipe used was a hot-rolled steel sheet with a plate thickness of 1.2 mm and a tensile strength of 440 MPa. Each of the connecting element members had an outer tube size of diameter: 80 mm and length: 300 mm, and flanges were provided at both ends as shown in FIG. In the connection, as shown in FIG. 4 or FIG. 5, a connecting plate (hot rolled steel plate having a tensile strength of 440 MPa, plate thickness 2 mm) was sandwiched between the connecting element members, and both flanges were joined by spot welding.
[0021]
About these connection members, the weight was made to collide with the collision speed shown in Table 1, and the site | part in which buckling generate | occur | produced and its deformation | transformation stroke were investigated. The results are shown in Table 1. From the same table, the distribution of the deformation amount in the axial direction (collision load input direction) of each connecting member changes according to the collision speed. From this, according to the third and fourth invention members, the connecting element It can be seen that by appropriately setting the cross-sectional shape of the member, it is possible to control the crushing site and the deformation amount according to the collision speed (energy at the time of collision).
[0022]
[Table 1]

[0023]
【The invention's effect】
According to the present invention, it is possible to easily and inexpensively manufacture a member having a high energy absorption capacity at the time of a car collision, and it is possible to reduce the weight of the vehicle as well as the safety of the occupant. Play.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a first invention member.
FIG. 2 is a cross-sectional view showing an example of a second invention member.
FIG. 3 is a schematic view showing an example of the member of the present invention in which a flange for connecting other members or the like is provided at the end.
FIG. 4 is a side view showing an example of a third invention member.
FIG. 5 is a side view showing an example of a fourth invention member.
FIG. 6 is an explanatory diagram showing how a collision load is applied to the front side frame.
FIG. 7 is a graph showing a ratio of energy absorption amounts of members A to D.
FIG. 8 is a graph showing a ratio of energy absorption amounts of members E to G.
[Explanation of symbols]
1, 1a, 10 round tube 2, 2a square tube 3 flange 4
11, 11a First invention member
20 Front side frame
21 Bumper
22 Impact load (energy)

Claims (6)

In a collision energy absorbing member that absorbs collision energy at the time of automobile collision by axial buckling of a metal pipe material among metal automobile body frame structural members, the inner pipe in which the metal pipe material is inserted into the outer pipe and the outer pipe The inner tube is fixed to the outer tube by welding or press-fitting, and has a closed cross-sectional shape in which a plurality of circular tubes and / or square tubes as inner tubes are inscribed in the circular tube as the outer tube. The collision energy absorption member characterized by the above-mentioned. In a collision energy absorbing member that absorbs collision energy at the time of automobile collision by axial buckling of a metal pipe material among metal automobile body frame structural members, the inner pipe in which the metal pipe material is inserted into the outer pipe and the outer pipe The inner pipe is fixed to the outer pipe by welding or press-fitting, and has a closed cross-sectional shape in which a plurality of circular pipes and / or square pipes as inner pipes are inscribed in the square pipe as the outer pipe. The collision energy absorption member characterized by the above-mentioned. In a collision energy absorbing member that absorbs collision energy at the time of automobile collision by axial buckling of a metal pipe material among metal automobile body frame structural members, the inner pipe in which the metal pipe material is inserted into the outer pipe and the outer pipe The inner pipe is fixed to the outer pipe by welding or press-fitting, and a partition wall is formed by one or a plurality of inner pipes and / or square pipes that are in contact with the entire length of the outer pipe. A collision energy absorbing member having a closed cross-sectional shape formed. In a collision energy absorbing member that absorbs collision energy at the time of automobile collision by axial buckling of a metal pipe material among metal automobile body frame structural members, the inner pipe in which the metal pipe material is inserted into the outer pipe and the outer pipe The inner pipe is fixed to the outer pipe by welding or press-fitting, and a partition wall is formed by one or a plurality of inner pipes and / or square pipes that are in contact with the entire length of the outer pipe. A collision energy absorbing member having a formed closed cross-sectional shape. 5. A collision energy absorbing member that absorbs collision energy at the time of automobile collision by axial buckling of a metal pipe member among metal automobile body frame structural members, and has a closed cross-sectional shape according to any one of claims 1 to 4. A collision energy absorbing member comprising a member and a circular tube or a square tube connected in the tube axis direction. 5. A collision energy absorbing member that absorbs collision energy at the time of automobile collision by axial buckling of a metal pipe member among metal automobile body frame structural members, and has a closed cross-sectional shape according to any one of claims 1 to 4. A collision energy absorbing member comprising a plurality of members connected to each other in the tube axis direction.

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