JPH0710032A - Connected structure member excellent in collision performance - Google Patents

Abstract

PURPOSE:To improve an average load value while restraining an increase in the maximum load at the time of a vehicle collision by using a bonding agent, whose elastic modulus differs in the longitudinal direction after hardening, in those having the flange surfaces of a closed cross section structure connected together in combination use with the bonding agent and a point connecting method. CONSTITUTION:This connected structure member, which is a straight member with a hat cross section made by forming a soft steel plate, is formed by connecting, for example, a side member 1 to a closing plate 2, by spot welds 3, No.1 spot weld pitch part 4 where a bonding agent A is not applied and a connected portion 5 where the bonding agent is applied. More than one kind of a bonding agent, whose elastic modulus successively increases, after hardening, in the longitudinal direction from the end of the flange surface where input of the collision load starts is used as a bonding agent. The elastic modulus, after hardening, of the bonding agent applied to the furthest position from the end of the flange surface where input of the collision load starts is set from 150 to 450kg/cm<2> while that of the bonding agent applied on other positions is set from 5 to 150kg/cm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a member of an automobile body, and more particularly to a joining structure of member structures such as a front side member, a hood rich reinforcement, an extension member, a rear side member, a side sill and a cross member. More specifically, the present invention relates to a joint structure member in which a flange surface having a closed cross-section structure is jointly joined by using one or more adhesives and a spot joining method.

[0002]

2. Description of the Related Art Conventionally, when assembling side sills, pillars, etc. of an automobile body, mass production of a vehicle body having a joint structure in which spot welds and structural adhesives are used together and the joints and welds coexist on the same flange surface Has been done. As described above, the effect of greatly improving the rigidity of the vehicle body and the vibration of the vehicle body is obtained by using the adhesion and the spot welding together at the above-mentioned portion.

[0003]

However, when the above-described joining structure using both adhesive and spot welding is applied to a member such as a front side member or a rear side member that receives an impact load during a vehicle collision, the average load in the latter half of the crushing Although the value improves, the maximum load value in the first half of the crush also increases accordingly.

Due to the increase in the maximum load value in the first half of the crushing, the reaction force balance of the vehicle body is disturbed, and the destruction of the joint portion between the member and the cabin may occur faster than the crushing of the member, resulting in a significant adverse effect on the reaction force of the entire vehicle body. there were.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a joining structure member which suppresses an increase in the maximum load when the members are crushed and significantly improves the average load as compared with the spot welding member.

[0006]

A joint structure member having excellent collision performance according to the present invention, which has achieved the above object, has a flanged surface having a closed cross-section structure with one or more kinds of adhesives, and a spot joining method,
For example, in the case of joint structural members that are jointly joined by spot welding, mechanical joining, etc., the length from the end of the flange surface where collision load input starts or at a certain distance from the end toward the opposite end The adhesive is applied in such a manner that the elastic modulus of the adhesive after curing is increased in the direction.

The adhesive used in the joint structure member of the present invention has an elastic modulus after curing of the adhesive applied at the position farthest from the end of the flange surface where the input of the collision load starts is 150-.
It is preferably 450 kg / cm ² , and the elastic modulus after curing of the adhesive applied to the other positions is preferably 5 to 150 kg / cm ² , and when two or more adhesives are used, The elastic modulus of the adhesive is gradually increased toward the opposite end.

[0008]

In accordance with the present invention, the bonded structural member does not use adhesive for a certain distance from the end where the impact load first enters at the time of collision, or is low from the end to the opposite end. Adhesive with low elasticity and low adhesive strength is used, and the other parts have a structure that is joined by using a combination of ordinary spot welding and adhesive with high adhesive strength. Therefore, the average load can be effectively improved by hardening the adhesive joint without increasing the maximum load.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Example 1, Comparative Examples 1 and 2 FIG. 1 shows a bonded structural member of Example 1. The structural member shown is a straight member having a hat cross-section formed of a member formed of a mild steel plate, and the side member 1 and the closing plate 2 are spot welded portions 3 and a first spot weld pitch portion where the adhesive A does not exist. 4 and the adhesive portion 5 using the adhesive A. The adhesive A is a one-component thermosetting epoxy adhesive, and Table 1 shows the physical property values of the adhesive A.

Next, for comparison, FIG. 2 shows a joint structure member of Comparative Example 1. 1 except that the adhesive A is also used in the first spot welding pitch portion where the adhesive A does not exist in FIG.
Is the same as. Moreover, the structural member of the comparative example 2 is shown in FIG.
The procedure is the same as that of the first embodiment except that the adhesive portion 5 in the first embodiment is omitted and the joining is performed only by spot welding.

Next, the operation of Example 1 and Comparative Examples 1 and 2 will be described in comparison. FIG. 4 shows the results of the carriage collision test performed on the members of Example 1 and Comparative Examples 1 and 2. The truck collision test was carried out with a truck load of 1780 KG and a truck speed of 30 km / h.
The following trolley collision tests were all performed under these conditions. Comparative example 2
The improvement of the average load of Comparative Example 1 is recognized as compared with Comparative Example 1. However, the maximum load also increases at the same time, which may break the reaction force balance condition at the time of a vehicle collision.

The collapse mode during the collision test was observed, and the results are shown in Table 1. The judgment of the collapsed state is indicated by O when the bellows-like collapse is good, and by Δ when it is not so good. In Comparative Example 2, the spot welds are squeezed periodically in a bellows manner as nodes, whereas in Comparative Example 1, the side members and the closing plate are relatively displaced between the spot weld pitches. The power to do works. However, due to the presence of the adhesive, the reaction force against the deformation works, the deformation is not performed smoothly, and it becomes difficult to make a bellows-like crush, resulting in a bad crush for collision energy absorption without periodicity. There is. This results in an increase in maximum load that occurs at the initial failure point.
Therefore, in Example 1 (FIG. 1), the adhesive is not used for the first spot pitch portion 4 (FIG. 1) where the collision load is input first in order to cause the bellows-like crushing reasonably. This can reduce the effect of adhesive bonding, which causes an increase in maximum load in the initial collapse.

The adhesive used in the present invention will be described below. The type of the adhesive used in the present invention is not particularly limited, and any structural adhesive may be used, and epoxy-based, acrylic-based, urethane-based adhesives and the like can be used.

Embodiment 2 FIG. 5 shows a joined structural member of Embodiment 2. The structural member shown in the drawing is a straight member having a hat cross-section formed of a member formed of a mild steel plate, and the side member 1 and the closing plate 2 are spot welded portions 3, an adhesive portion 5 using an adhesive agent A, and an adhesive agent. It is joined by the adhesive portion 6 using B. The adhesive A and the adhesive B are one-component thermosetting epoxy adhesives, and Table 1 shows the physical property values of the adhesive A and the adhesive B. The elastic modulus of the adhesive B is smaller than that of the adhesive A. If this relationship is not satisfied, the effect of suppressing the maximum load and significantly improving the average load cannot be obtained.

Next, the operation will be described. When impact load is input Adhesive B with low shear strength is used in the first pitch portion of spot welding, so when impact load is input, smoother crushing is induced and more impact energy is absorbed, resulting in maximum load. It has become possible to efficiently suppress the increase in the load and improve the average load.

Example 3 FIG. 6 shows a joined structural member of Example 3. The structural member shown in the drawing is a straight member having a hat cross-section formed of a member formed of a mild steel plate, and the side member 1 and the closing plate 2 are spot welded parts 3, a part 4 which does not use an adhesive, and an adhesive A. They are joined by the adhesive portion 5 used and the adhesive portion 6 using the adhesive B. The adhesive A and the adhesive B are one-component thermosetting epoxy adhesives, and Table 1 shows the physical property values of the adhesive A and the adhesive B.

Embodiment 4 FIG. 7 shows a joined structural member of Embodiment 4. The structural member shown in the drawing is a straight member having a hat cross-section formed of a member formed of a mild steel plate, and the side member 1 and the closing plate 2 are spot welded parts 3, a part 4 which does not use an adhesive, and an adhesive A. They are joined by the adhesive portion 5 used, the adhesive portion 6 using the adhesive B, and the adhesive portion 7 using the adhesive C. The adhesive A, the adhesive B and the adhesive C are one-component thermosetting epoxy adhesives, and Table 1 shows the physical property values of the adhesive A, the adhesive B and the adhesive C.

Example 5 FIG. 8 shows a joined structural member of Example 5. The illustrated structural member is a straight member having a hat cross-section formed of a member formed of a mild steel plate, and the side member 1 and the closing plate 2 are spot-welded portions 3, an adhesive portion 5 using an adhesive agent 5, an adhesive agent. They are joined by an adhesive portion 6 using B and an adhesive portion 7 using an adhesive C. The adhesive A, the adhesive B and the adhesive C are one-component thermosetting epoxy adhesives, and Table 1 shows the physical property values of the adhesive A, the adhesive B and the adhesive C. Regarding the members of the above Examples 2 to 5, Example 1
Carry out a collision test similar to the above, observe the collapse mode,
It is also shown in Table 1.

[0019]

[Table 1] Next, the range of elastic modulus of the adhesive used will be described in Examples and Comparative Examples.

Examples 6 to 9 In Examples 6 to 9, the adhesive A and the adhesive B of Example 3 are shown in Table 2.
As shown in FIG. 5, a bonded structure member was produced in the same manner as in Example 2 except that the elastic modulus was changed within the preferable range defined by the present invention. Table 2 shows the results of the truck collision test.

Comparative Examples 3 to 8 Comparative Examples 3 to 8 are the same as Example 3 except that the adhesive A and the adhesive B of Example 2 were changed out of the specified range of the present invention as shown in Table 2. A bonded structural member was produced. The results of the truck collision test are shown in Table 2 and described. In addition, when the crushed state was judged to be defective, it was marked with x.

According to the present invention, when two or more kinds of adhesives are used, the adhesives are arranged so that the elastic modulus of the adhesives increases from the end where the input of the impact load starts to the end on the opposite side. An adhesive having a range of elastic modulus shown in is desired. That is, it is desirable that the elastic modulus of the adhesive used in the region including the end opposite to the end where the impact load is input (hereinafter, the adhesive having the highest elastic modulus) is 150 to 450 kg / cm ² , more preferably It is 250 to 380 kg / cm ² . Also it is desirable range of the elastic modulus of the highest modulus adhesive other than the adhesive agent is 5~150kg / cm ^2, more preferably from 20~80kg / cm ^2. If the elastic modulus of the adhesive having the highest elastic modulus used in the present invention is less than 150 kg / cm ² , the shear strength required at this portion is insufficient and the average load improving effect cannot be obtained. Also, the elastic modulus of the adhesive used in this area is 450
If it exceeds kg / cm ² , brittle fracture of the adhesive layer is further promoted and the shear strength is remarkably lowered, so that the desired effect cannot be obtained.
In addition, the elastic modulus of the adhesives other than the adhesive having the highest elastic modulus is 5
If it is less than kg / cm ² , the shear strength is remarkably reduced and the maximum load can be reduced, but the average load cannot be effectively improved. Also, the elastic modulus of the adhesive used in this area
If it exceeds 150 kg / cm ² , since the shear strength near the end where the impact load is input is too large, the average load is improved but the maximum load is also increased.

Comparative Examples 9 and 10 Adhesives in Example 5 (Adhesive A: 5, Adhesive B:
6, a bonding structure member was produced in the same manner as in Example 5 except that the arrangement of the adhesive C: 7) was changed as shown in FIGS. Carrying collision test of these members, observing the collapsed state,
The results are shown in Table 2. If the arrangement of the adhesive is not specified in the present invention, the bellows crushing does not occur satisfactorily, and therefore it is not possible to both suppress the maximum load and improve the average load.

[0024]

[Table 2]

Further, in a member having a closed cross-section structure in which the flange surface of the present invention is bonded using both bonding and spot welding, rivets, bolts, mechanical clinches and projection welding can be used instead of spot welding used for the bonding surface. Is.

[0026]

As described above, according to the present invention, it is possible to obtain the joining structure capable of improving the average load value while suppressing the increase of the maximum load by the joining structure which maximizes the effect of the adhesive joining.

[Brief description of drawings]

FIG. 1 is a perspective view of a joint structure member having a hat cross section according to a first embodiment.

2 is a perspective view of a joint structure member having a hat cross section of Comparative Example 1. FIG.

3 is a perspective view of a joint structure member having a hat cross section of Comparative Example 2. FIG.

FIG. 4 is a graph showing the relationship between load and displacement in a carriage collision test of the joint structure members of Example 1 and Comparative Examples 1 and 2.

FIG. 5 is a perspective view of a joint structure member having a hat cross section of the second embodiment.

FIG. 6 is a perspective view of a joint structure member having a hat cross section of Example 3;

FIG. 7 is a perspective view of a joint structure member having a hat cross section of Example 4;

FIG. 8 is a perspective view of a joint structure member having a hat cross section of Example 5;

9 is a perspective view of a joint structure member having a hat cross section of Comparative Example 9. FIG.

10 is a perspective view of a joint structure member having a hat cross section of Comparative Example 10. FIG.

[Explanation of symbols]

1 Sand Member 2 Closing Plate 3 Spot Welding Part 4 First Spot Welding Pitch Part or Part without Adhesive 5 Adhesive with Adhesive A 6 Adhesive with Adhesive B 7 Adhesive with Adhesive C Department

Claims (2)

[Claims] 1. A joint structure member in which a flange surface having a closed cross-section structure is jointly joined by using one or more kinds of adhesives and a point joining method together, from or at the end of the flange surface where the input of a collision load starts. A bonded structural member having excellent collision performance, characterized in that an adhesive having an elastic modulus of the cured adhesive sequentially increased in the longitudinal direction is applied to the opposite end portion at a certain distance from the portion. . 2. The joined structural member according to claim 1, wherein
The elastic modulus after curing of the adhesive applied at the position farthest from the end of the flange surface where collision load input begins is 150 to 450 k.
g / cm ² , and the elastic modulus after curing of the adhesive applied to other positions is 5 to 150 kg / cm ² , a bonded structural member.