JP6838432B2 - Impact resistant parts of automobiles - Google Patents

Description

The present invention relates to an impact-resistant member, specifically, an impact-resistant member that suppresses deformation of a vehicle body at the time of a collision of an automobile.

The mainstream of automobile bodies is a monocoque structure. In the monocoque structure, a steel plate is usually press-molded into a part having a flange part called a hat part, and the flange parts of the hat part are joined by spot welding to form a box-shaped part, and then a plurality of box-shaped parts are formed. Is composed of being combined. For example, the structural members of the side members that make up the automobile body must have the ability to absorb shocks at the time of a collision, so-called shock absorption performance, and have the ability to suppress deformation in the room at the time of impact, so-called shock resistance performance. Needed.

The above-mentioned side member is in the vehicle length direction regardless of whether it is the front side member 100 arranged at the front end of the vehicle body as shown in FIG. 1 or the rear side member 200 arranged at the rear end of the vehicle body as shown in FIG. It is a long part. Of these members, the front side member front 101 receives an impact load from the front in the vehicle length direction in the event of a frontal collision, and the rear side member rear 201 receives an impact load from the rear in the vehicle length direction in the event of a rear collision. Entered. At this time, the impact is absorbed by the axial crushing deformation and bending deformation of the front side member front 101 and the rear side member rear 201. On the other hand, the front side member rear 102 and the rear side member front 202 have sufficient proof stress and do not significantly deform with respect to the input load, and suppress deformation in the room. In the present specification, members having a function of suppressing deformation in the room when an impact load is input, such as the front side member rear 102 and the rear side member front 202, are collectively referred to as "impact resistant members".

FIG. 3 is a conventional impact resistant member 20 provided on the front side of a vehicle such as the front side member rear 102. The impact resistant member 20 extends in the vehicle length direction L, and is formed so as to be inclined upward in the vehicle height direction V from the rear in the vehicle length direction to the front in the vehicle length direction by the bent portion 1a. That is, the center of curvature 1b of the bent portion 1a of the impact resistant member 20 is located above the bent portion 1a in the vehicle height direction V.

As shown in FIG. 4, the impact resistant member 20 is composed of a hat channel member 2 and a plate-shaped member 3 which are convex downward in the vehicle height direction V in a cross section perpendicular to the vehicle length direction L. The hat channel member 2 includes a lower surface portion 2a, a side wall portion 2b connected to the lower surface portion 2a and extending upward in the vehicle height direction V, and a flange portion 2c connected to the side wall portion 2b and extending in the vehicle width direction W. It is joined to the plate-shaped member 3 at the flange portion 2c.

When an impact load is input to the impact resistant member 20 from the front in the vehicle length direction, the load increases with deformation, but the maximum load is reached at a certain point. At this time, in the impact resistant member 20, the side wall portion 2b near the flange portion 2c is deformed inward in the cross section as shown in FIG. 5, and then buckled at the bent portion 1a shown in FIG.

FIG. 6 shows another form of the conventional impact resistant member 30. As shown in FIG. 7, the impact-resistant member 30 is formed by adding a hat channel-shaped reinforcing member 40 that is convex upward in the vehicle height direction V to the impact-resistant member 20. The reinforcing member 40 is joined to the plate-shaped member 3 and the hat channel member 2 at the flange portion.

When an impact load is input to the impact resistant member 30 from the front in the vehicle length direction, the load increases with deformation, but the maximum load is reached at a certain point. At this time, buckling occurs at the bent portion 1a as in the above-mentioned impact-resistant member 20, but the amount of deformation of the side wall portion 2b near the flange portion 2c immediately before buckling changes little with respect to the impact-resistant member 20. .. That is, the maximum load of the impact-resistant member 30 at the time of inputting the impact load is larger than that of the impact-resistant member 20, and the deformation of the room can be suppressed with respect to the impact-resistant member 20. However, since the reinforcing member 40 of the impact resistant member 30 has a hat channel shape that is convex upward in the vehicle height direction V, the interior space is narrowed.

As a conventional impact resistant member, there is also one described in Patent Document 1. Patent Document 1 discloses an invention in which the proof stress is enhanced by forming the floor panel into a convex shape among the front side member and the floor panel constituting the closed cross-sectional structure of the front side member rear of the automobile.

JP-A-2009-166718

The impact resistant member is required to improve the yield strength without narrowing the indoor space. However, the impact-resistant member of Patent Document 1 has a convex shape upward in the vehicle height direction, and has a problem of narrowing the interior space. Further, in the bent portion where the center of curvature exists above in the vehicle height direction, the effect of suppressing the deformation inward in the cross section in the vicinity of the flange is not sufficient, so that the proof stress cannot be sufficiently increased.

The present invention has been made in view of the above circumstances, and (a) a bent portion is formed so as to extend along the vehicle length direction and incline in the vehicle height direction from the middle, and the center of curvature of the bent portion is formed. When an impact load is applied to the impact-resistant member existing above the bent portion in the vehicle height direction, (b) the interior space is not narrowed, and (c) the cross-sectional deformation of the bent portion is suppressed. , The purpose is to increase the bearing capacity.

In order to solve the above problems, the present inventors diligently examined the occurrence of cross-sectional deformation of the bent portion, and as a result, arranged a convex reinforcing member in a closed cross-sectional space formed by a hat channel member and a plate-shaped member. The present invention was completed with the finding that is effective.

That is, the present invention is as listed below.
(1) The resistance of an automobile in which a bent portion is formed so as to extend in the vehicle length direction of the automobile and incline in the vehicle height direction from the middle, and the center of curvature of the bent portion is above the bent portion in the vehicle height direction. A plate-shaped member that is an impact member and is joined to a hat channel member that is convex downward in the vehicle height direction and a flange portion of the hat channel member to form a closed cross section with the hat channel member in a cross section perpendicular to the vehicle length direction. And a reinforcing member having an upper surface portion extending in the vehicle length direction so as to follow the shape of the plate-shaped member and a side wall portion extending downward in the vehicle height direction from both ends of the upper surface portion. Provided in a space having a closed cross section, the side wall portion of the reinforcing member and the side wall portion of the hat channel member are joined to each other, and the reinforcing member is provided at the bent portion and the bent portion of the reinforcing member is bent. The relationship between the inner circumferential length L1 and the length L2 from the curvature stop of the curved portion to the end of the straight portion of the reinforcing member is formed so as to satisfy 0.27 ≦ L2 / L1 ≦ 0.67. The shock-resistant material of automobiles .
(2 ) A joint portion extending in the longitudinal direction of the member is formed from the end of the side wall portion of the reinforcing member in the longitudinal direction of the member, and the joint portion and the side wall portion of the hat channel member are joined to each other ( 1). ) Is the shock-resistant member of the automobile.
( 3 ) The impact-resistant member of an automobile according to (1) or 2 , which is used for a front side member.
( 4 ) The impact-resistant member of an automobile according to (1) or 2 , which is used for a rear side member.

According to the present invention, it is possible to improve the yield strength of the impact-resistant member of an automobile.

It is a figure which shows the example of the front side member of an automobile. It is a figure which shows the example of the rear side member of an automobile. It is a side view which shows the schematic shape of the conventional impact resistant member. FIG. 3 is a cross-sectional view taken along the line AA in FIG. It is sectional drawing which shows the deformed state of the conventional impact resistant member. It is sectional drawing which shows the schematic shape of another conventional impact resistant member. FIG. 6 is a cross-sectional view taken along the line BB in FIG. It is a side view which shows the schematic shape of the impact resistant member which concerns on 1st Embodiment of this invention. FIG. 8 is a cross-sectional view taken along the line CC in FIG. It is a side view which shows the schematic shape of the reinforcing member which concerns on 1st Embodiment of this invention. It is a side view which shows the schematic shape of the impact resistant member which concerns on 2nd Embodiment of this invention. It is a side view which shows the schematic shape of the reinforcing member which concerns on 2nd Embodiment of this invention. It is a perspective view which shows the schematic shape of the reinforcing member which concerns on 3rd Embodiment of this invention. It is a figure which compared the load characteristic of the conventional impact resistant member and the impact resistant member which concerns on this invention. The ratio (L2 / L1) of the length L2 from the curvature stop of the reinforcing member curved portion of the impact resistant member to the end of the straight portion and the circumferential length L1 inside the bending of the reinforcing member curved portion according to the present invention. It is a figure which shows the relationship with the maximum load / member weight.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted. Further, in the following description, the impact resistant member arranged on the front of the vehicle body will be described as an example, but in the following description, "front" will be read as "rear" and "rear" will be read as "front". An impact resistant member arranged at the rear of the vehicle body can be configured.

<First Embodiment>
As shown in FIG. 8, the impact resistant member 1 according to the first embodiment extends in the vehicle length direction L, and is inclined upward in the vehicle height direction V from the rear to the front in the vehicle length direction L by the bent portion 1a. It is formed to do. That is, the impact resistant member 1 has a bent portion 1a formed so as to be long in the vehicle length direction L and inclined in the vehicle height direction from the middle, and the curvature center 1b of the bent portion 1a is larger than the bent portion 1a. It is located above the vehicle height direction V.

The impact resistant member 1 is composed of a hat channel member 2 that is convex downward in the vehicle height direction V and a plate-shaped member 3 in a cross section perpendicular to the vehicle length direction L as shown in FIG. The hat channel member 2 is formed by press working, and is connected to the lower surface portion 2a, the side wall portion 2b connected to the lower surface portion 2a and extending upward in the vehicle height direction V, and connected to the side wall portion 2b in the vehicle width direction W. It has a flange portion 2c to be stretched. The hat channel member 2 and the plate-shaped member 3 are joined by a flange portion 2c, whereby a closed cross section is formed. Laser welding, arc welding, or spot welding may be used for joining the flange portion 2c and the plate-shaped member 3, but spot welding is usually used.

As shown in FIG. 9, a reinforcing member 4 is provided in the closed cross-sectional space 5 formed by the hat channel member 2 and the plate-shaped member 3. The reinforcing member 4 has an upper surface portion 4a extending in the vehicle length direction so as to follow the shape of the plate-shaped member 3, and a side wall portion 4b extending downward from both ends of the upper surface portion 4a in the vehicle height direction V. As shown in FIG. 10, the reinforcing member 4 is formed so as to be along the longitudinal direction of the member of the impact resistant member 1, and the curved portion 4c having the same position as the center of curvature 1b of the bent portion 1a of the impact resistant member 1 as the center of curvature. And a straight portion 4d extending linearly from the curved portion 4c in the longitudinal direction of the member. In the present specification, the “member longitudinal direction” refers to the position of the center of gravity (center of gravity) of the minute cross section of the impact resistant member 1 which is a cross section perpendicular to the vehicle length direction L at one end of the impact resistant member 1 in the vehicle length direction L. It is the direction of the line obtained by connecting from to the other end. Further, the term "straight line" of the reinforcing member 4 in the present specification includes not only a strict straight line but also a substantially straight line concept.

As shown in FIG. 9, the reinforcing member 4 is fixed by joining the side wall portion 4b and the side wall portion 2b of the hat channel member 2 to each other. The side wall portion 2b of the hat channel member 2 and the side wall portion 4b of the reinforcing member 4 may be joined by any of laser welding, arc welding, and spot welding, but spot welding is usually used.

The impact resistant member 1 of the first embodiment is configured as described above. When an impact load is input to the end portion of the impact resistant member 1 in the vehicle length direction, even if the side wall portion 2b near the flange portion 2c tries to deform inward in the cross section as shown in FIG. 5, the side wall portion near the flange portion 2c The deformation of the reinforcing member 4 arranged in the portion 2b is suppressed, and the proof stress can be improved. That is, the maximum input load at the time of impact load can be increased. Further, since the reinforcing member 4 is arranged in the closed cross-section space 5, the interior space is not narrowed as in the impact resistant member 30 shown in FIG. Therefore, according to the impact resistant member 1, it is possible to improve the proof stress without narrowing the indoor space.

<Second Embodiment>
As shown in FIG. 11, unlike the first embodiment, the impact resistant member 1 of the second embodiment is provided with the reinforcing member 4 only in the vicinity of the bent portion 1a, not in the entire longitudinal direction of the member. Although it is possible to improve the proof stress even if the reinforcing member 4 is provided in a portion other than the bent portion in the longitudinal direction of the member, the deformation of the side wall portion 2b of the hat channel member 2 as shown in FIG. Since it occurs remarkably in the vicinity of the bent portion 1a, it is preferable that the reinforcing member 4 is provided at least in the bent portion 1a. Thereby, the yield strength can be effectively improved. In particular, if the reinforcing member 4 is provided only in the vicinity of the bent portion 1a as in the second embodiment, the proof stress can be improved while reducing the weight.

From the viewpoint of mass efficiency with respect to the maximum load input to the impact resistant member 1, as shown in Examples described later, the bending inner circumferential length L1 of the curved portion 4c of the reinforcing member 4 shown in FIG. 12 It is preferable that the relationship with the length L2 from the curvature stop 1c of the curved portion 4c to the end of the straight portion 4d satisfies 0.27 ≦ L2 / L1 ≦ 0.67. As a result, the effect of improving the proof stress against the increase in weight when the reinforcing member 4 is provided can be efficiently obtained.

<Third Embodiment>
In the third embodiment, the reinforcing member 4 has a shape as shown in FIG. Specifically, a joint portion 4e extending from the end of the side wall portion 4b of the reinforcing member 4 in the member longitudinal direction, that is, the end of the straight portion 4d in the member longitudinal direction is formed. Since the reinforcing member 4 is provided with such a joint portion 4e, when the joint portion 4e and the side wall portion 2b of the hat channel member 2 are spot welded, it becomes easy to sandwich the joint portion 4e with the electrodes of the spot weld, and the spot weld is performed. Easy to assemble.

Although the embodiments of the present invention have been described above, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical idea described in the claims, and of course, the technical scope of the present invention also includes them. It is understood that it belongs to.

A model of a conventional impact-resistant member and an impact-resistant member according to the present invention was created, and a simulation was performed in which an impact load was input from the end of the impact-resistant member in the vehicle length direction.

The conventional impact-resistant members used in the simulation have a structure in which a closed cross section is formed by a hat channel member and a plate-shaped member as shown in FIG. 4 (Comparative Example 1), and a hat channel as shown in FIG. The structure is such that a closed cross section is formed by the member and the plate-shaped member, and a reinforcing member that is convex upward in the vehicle height direction is provided above the plate-shaped member (Comparative Example 2). The hat channel members of Comparative Examples 1 and 2 are 980 MPa class and have a plate thickness of 2.0 mm, and the plate-shaped members are 270 MPa class and have a plate thickness of 1.2 mm. The reinforcing member of Comparative Example 2 is a 590 MPa class and has a plate thickness of 1.2 mm.

The impact-resistant member according to the present invention used in the simulation has a structure in which a closed cross section is formed by a hat channel member and a plate-shaped member as shown in FIG. 9, and a reinforcing member is provided in the closed cross section space (Example). 1). In Example 1, as in the comparative example, the hat channel member is 980 MPa class and has a plate thickness of 2.0 mm, the plate-shaped member is 270 MPa class and has a plate thickness of 1.2 mm, and the reinforcing member is 590 MPa class and has a plate thickness of 1.2 mm.

To apply the impact load, apply the rigid body wall to one end of the impact resistant member in the vehicle length direction (impact load input side end), and then move the rigid wall toward the other end (cabin side end) in the vehicle length direction. Do it by letting it do. Then, the displacement amount and the input load of the rigid body wall at that time are measured.

FIG. 14 shows a diagram comparing the relationship between the displacement of the rigid body wall and the load. The vertical axis in the figure shows the load ratio obtained by dividing the measured load by the maximum load of Comparative Example 1. It can be seen that the load increases from the start of deformation at all levels and tends to reach the maximum load at some point. The maximum load is higher in Comparative Example 2 than in Comparative Example 1. However, Comparative Example 2 has a drawback of narrowing the indoor space as compared with Comparative Example 1. On the other hand, Example 1 has a higher maximum load than Comparative Example 2. In addition to this, Example 1 does not narrow the indoor space as compared with Comparative Example 2. From the above, according to the impact-resistant member according to the present invention, the maximum load, that is, the proof stress can be increased without narrowing the indoor space.

Table 1 below shows the amount of deformation of the side wall of the hat channel member in the vicinity of the flange immediately before the maximum load. The amount of deformation is represented by the change ΔW in the width between the opposing side wall portions. The numerical value in the table is the ΔW ratio divided by ΔW in Comparative Example 1.

The ΔW ratio is the smallest in Example 1. From this, it was shown that the impact-resistant member according to the present invention suppresses the deformation of the side wall portion of the hat channel member in the vicinity of the flange portion inward in the cross section. From the above, it has been shown that according to the present invention, deformation of the side wall portion of the hat channel member in the vicinity of the flange portion is suppressed and the maximum load, that is, the proof stress is increased.

Next, as the impact-resistant member according to the present invention, a model having a structure in which the reinforcing member is provided only in the vicinity of the bent portion as shown in FIG. 11 is created, and the straight portion is formed from the curvature stop of the reinforcing member curved portion shown in FIG. A simulation was carried out in which the length L2 was changed to the end of. The materials and thickness of the hat channel member, the plate-shaped member, and the reinforcing member are the same as those in the first embodiment.

The vertical axis of FIG. 15 is the mass efficiency with respect to the maximum load obtained by dividing the maximum load input to the impact resistant member by the weight, and is standardized by the value of Comparative Example 1. The horizontal axis of FIG. 15 is the ratio of the length L2 from the curvature stop of the reinforcing member bent portion to the end of the straight portion extending toward the impact load input side and the circumferential length L1 inside the bending of the reinforcing member bent portion. .. In this simulation, the length from the curvature stop of the bending portion of the reinforcing member to the end of the straight portion extending toward the passenger compartment is also set to L2.

As shown in FIG. 15, the value of mass efficiency increases from 0 to 0.27 for L2 / L1. It can be seen that there is almost no change in mass efficiency when L2 / L1 is from 0.27 to 0.67, and it decreases after that. From this, from the viewpoint of mass efficiency with respect to the maximum load, the ratio of the length L2 from the curvature stop of the reinforcing member bending portion to the end of the straight portion and the circumferential length L1 inside the bending of the reinforcing member bending portion is It is preferable to satisfy 0.27 ≦ L2 / L1 ≦ 0.67. If a reinforcing member is provided so as to satisfy this, the effect of improving the proof stress against the increase in weight can be efficiently obtained.

Next, as the impact-resistant member according to the present invention, a model (Example 2) having a structure in which a joint portion for spot welding is provided on the reinforcing member as shown in FIG. 13 and a conventional impact-resistant member are shown in FIG. A structural model (Comparative Example 3) was created, and a simulation of applying an impact load was carried out. The materials and thickness of the hat channel member, the plate-shaped member, and the reinforcing member of the second embodiment and the third comparative example are the same as those of the above simulation.

Further, as a conventional impact-resistant member, a plate-shaped member is used as compared with Comparative Example 1, an impact-resistant member having a hat channel member of 980 MPa class and a plate thickness of 2.3 mm (Comparative Example 4), and Comparative Example 1. A model of an impact-resistant member (Comparative Example 5) having a 270 MPa class and a plate thickness of 1.8 mm was created, and a simulation of applying an impact load was carried out.

The results of comparing the maximum load and weight at that time are shown in Table 2 below. In addition, each is standardized by the value of Comparative Example 1.

The maximum load ratio is the highest in Example 2, and the weight ratio is the smallest in Example 2. From this, it was shown that the present invention can increase the light weight and the maximum load, that is, the proof stress.

According to the result of this embodiment, a bent portion is formed so as to extend along the vehicle length direction and incline in the vehicle height direction from the middle, and the center of curvature of the bent portion is upward in the vehicle height direction with respect to the bent portion. It is shown that when an impact load is input to the impact-resistant member existing in the above, the proof stress is improved by suppressing the cross-sectional deformation of the bent portion without narrowing the indoor space.

In the present invention, a bent portion is formed so as to extend along the vehicle length direction and incline in the vehicle height direction from the middle, and the center of curvature of the bent portion exists above the bent portion in the vehicle height direction. Applicable to members.

1 Impact resistant member 1a Bending part 1b Center of curvature of bending part 1c Curvature stop of bending part 2 Hat channel member 2a Lower surface part 2b Side wall part 2c Flange part 3 Plate-shaped member 4 Reinforcing member 4a Upper surface part 4b Side wall part 4c Curved part 4d Straight line Part 4e Joint 5 Closed section space 20 Conventional impact resistant member 30 Conventional impact resistant member 40 Conventional reinforcing member 100 Front side member 101 Front side member Front 102 Front side member Rear 200 Rear side member 201 Rear side member Rear 202 Rear side member Front L Vehicle length direction L1 Circumferential length inside the bending of the reinforcing member bending part L2 Length from the curvature stop of the reinforcing member bending part to the end of the straight part V Vehicle height direction W Vehicle width direction

Claims (4)

An impact-resistant member of an automobile in which a bent portion is formed so as to extend in the vehicle length direction of the automobile and incline in the vehicle height direction from the middle, and the center of curvature of the bent portion exists above the bent portion in the vehicle height direction. There,
A hat channel member that is convex downward in the vehicle height direction,
A plate-shaped member that is joined to the flange portion of the hat channel member and forms a closed cross section with the hat channel member in a cross section perpendicular to the vehicle length direction.
It is provided with an upper surface portion extending in the vehicle length direction so as to follow the shape of the plate-shaped member, and a reinforcing member having side wall portions extending downward in the vehicle height direction from both ends of the upper surface portion.
The reinforcing member is provided in the space of the closed cross section, and the side wall portion of the reinforcing member and the side wall portion of the hat channel member are joined to each other .
The reinforcing member is provided at the bent portion, and has a circumferential length L1 inside the bent portion of the bent portion of the reinforcing member and a length from the curvature stop of the bent portion to the end of the straight portion of the reinforcing member. An automobile impact resistant member, characterized in that the relationship with L2 is formed so as to satisfy 0.27 ≦ L2 / L1 ≦ 0.67. A joint portion extending in the longitudinal direction of the member is formed from the end of the side wall portion of the reinforcing member in the longitudinal direction of the member, and the joint portion and the side wall portion of the hat channel member are joined to each other. The impact resistant member of the automobile according to claim 1. The impact-resistant member of an automobile according to claim 1 or 2 , characterized in that it is used for a front side member. The impact-resistant member of an automobile according to claim 1 or 2 , characterized in that it is used for a rear side member.

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