JPH04287742A - Bumper fitting structure - Google Patents

Abstract

PURPOSE:To improve the shock absorbing performance by forming inner and outer vertical walls in the vehicle width direction at the fitting end section of a vehicle body strength member, folding the inner vertical wall inward by the preset angle in the vehicle width direction, forming an escape section for the outer vertical wall on the outside face of the fitted end section of a bow- shaped bumper stay, and rotatably fitting the fitted end section to the fitting end section. CONSTITUTION:An inner vertical wall section 6a and an outer vertical wall section 6b are formed near the inside and near the outside respectively in the vehicle width direction at a fitting end section 6 to the bumper stay 2 of a vehicle body strength member 5. The fitted end section 3 of the bumper stay 2 is inserted between the inner and outer vertical wall sections 6a, 6b and rotatably fitted with a bolt 8. When a bumper 1 is made nearly linear at the time of a collision of a vehicle body, the inner vertical wall section 6a is bent so that the inner contact section 3b of the fitted end section 3 is brought into no contact. An R'-shaped escape section 7 is formed on the inner contact section 3b of the fitted end section 3 so that it is brought into no contact with the outer vertical wall section 6b when the bumper 1 is deformed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved structure for attaching a substantially arcuate bumper to a vehicle body.

0002

2. Description of the Related Art In recent years, many automobiles have curved front and rear portions of the vehicle body, and bumpers are also formed in a substantially arcuate shape following this curve.

As shown in FIG. 6, this bumper 1 is composed of a bumper armature 1a and a bumper fascia (not shown), and is supported by a vehicle body strength member 3 via a pair of bumper stays 2 (one not shown). There is.

As shown in FIG. 7, the vehicle body strength member 3 has a closed cross-sectional structure in which a closing plate 3b is joined to a front side member 3a.

[0005] An attached end 5 of the bumper stay 2 is inserted into the attachment end 4 at the tip of the vehicle body strength member 3, and is attached by bolts 6 and nuts 7 extending in the vertical direction.

On the other hand, as another structure, as shown in FIGS. 8 and 9, the end of the attached end 5 of the bumper stay 2,
In some cases, flange portions F are formed at the mounting end portions 4 of the vehicle body strength member 3, and these flange portions F are fixed by tightening bolts.

[0007]

[Problem to be solved by the invention] However, FIG.
As shown in the middle (A), when an impact force in the direction of the arrow is applied to the bumper 1 due to a vehicle collision, the substantially arcuate bumper 1 becomes substantially straight as shown from the two-dot chain line to the solid line in the figure. With this deformation of the bumper 1, the bumper stay 2 attached to the bumper 1 changes its direction outward in the vehicle width direction. Since the bumper stay 2 and the vehicle body strength member 3 are attached via the bolts 6, the vehicle body strength member 3 is bent outward in the vehicle width direction. When an impact force is further applied to the bent vehicle body strength member 3, as shown in (B) in FIG.
Since a large bending moment M acts on this vehicle body strength member 3, buckling is likely to occur. Therefore, the vehicle body strength member 3 is made larger to maintain its ability to absorb impact force. In addition, in the case of the conventional example shown in (A) in FIG.
As shown in B), buckling is likely to occur at several locations due to the action of the bending moment M, so the vehicle body strength member 3 is made larger in this case as well. Such an increase in the size of the vehicle body strength member 3 causes an increase in vehicle weight and manufacturing cost.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to generate an impact force and a bending moment that bends the vehicle body strength member outward in the vehicle width direction without increasing the size of the vehicle body strength member;
The impact force is divided into a force that generates a bending moment that bends the vehicle body strength member inward in the vehicle width direction, and the resultant force becomes a compressive load that crushes the vehicle body strength member, and the impact force is applied to the vehicle body strength member. To provide an automobile bumper mounting structure capable of sufficiently absorbing impact force by inducing crushing of a vehicle body strength member when the vehicle is hit.

[0009]

[Means for Solving the Problems] In order to solve the above-mentioned problems, a bumper mounting structure according to the present invention provides a vehicle body strength that extends in the vehicle longitudinal direction through at least a pair of bumper stays. In a bumper mounting structure that is attached to a mounting end of a member, the mounting end has an inner standing wall portion located inward in the vehicle width direction and an outer standing wall portion located outside in the vehicle width direction, and the mounting end portion has an inner standing wall portion located closer to the outside in the vehicle width direction, and the mounting end portion has an inner standing wall portion closer to the outside in the vehicle width direction, and the mounting end portion has an inner standing wall portion closer to the inner side in the vehicle width direction and an outer standing wall portion closer to the outer side in the vehicle width direction. has a cross-sectional shape into which an attached end portion of the bumper stay is inserted, and the attached end portion has an inner abutting portion facing the inner vertical wall portion and an outer abutting portion facing the outer vertical wall portion. The bumper stay is rotatably attached via an axis in the vertical direction in a state where the attached end portion of the bumper stay is inserted into the attachment end portion of the vehicle body strength member, and the inner vertical wall portion of the attachment end portion is , the bumper is bent at a predetermined angle so that the inner abutting portion of the attached end comes into contact when the bumper is in a substantially straight state during a vehicle collision, and the outer abutting portion of the attached end has the It is characterized in that a relief portion is formed so that the mounting end portion does not come into contact with the outer vertical wall portion in the event of a vehicle body collision.

0010

[Function] According to the bumper mounting structure according to the present invention, when a vehicle collision occurs, the substantially arcuate bumper becomes substantially straight, the bumper stay also moves accordingly, and the impact force is transmitted through the bumper stay. Input to the vehicle body strength member. At this time, the attached end of the bumper stay rotates about the axis relative to the attached end of the vehicle body strength member. During this rotation, the relief portion formed in the bumper stay outer contact portion prevents the outer contact portion from coming into contact with the outer vertical wall portion of the vehicle body strength member. When the bumper is in a substantially straight state, the inner abutting portion of the bumper stay abuts the inner vertical wall portion of the vehicle body strength member. A load acts on the vehicle body strength member through this contact portion. As a result, the impact force is decomposed into a force transmitted to the vehicle body strength member through the shaft and a force transmitted to the vehicle body strength member through the contact portion. The former force acts as a bending moment that deflects the vehicle body strength member outward in the vehicle width direction, and the latter force acts as a bending moment that deflects the vehicle body strength member inward in the vehicle width direction. Due to the bending moments in these different directions, the bending moment acting on the vehicle body strength member is smaller than in the past, and the impact load mainly acts in a direction that compresses the vehicle body strength member. Therefore,
Since the car body strength member is prevented from breaking and can absorb impact force by collapsing due to compression, impact force can be effectively absorbed without increasing the size of the car body strength member as in the past. On the other hand, if a slight impact force is applied in a light vehicle collision and the roughly arcuate bumper is deformed to a substantially straight state before the impact force is released, the inside abutting part of the bumper stay will It does not come into contact with the inner abutting part of the strength member, or even if it does, it only applies a small amount of force. Therefore, the vehicle body strength members are not damaged, and only the bumper needs to be replaced.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the bumper mounting structure according to the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a bumper, and the bumper 1 has a substantially arcuate shape with an angle α between its longitudinal centerline and the vehicle width direction. A bumper stay 2 is attached to the bumper 1. An attached end portion 3 is provided at the end of the bumper stay 2 . As shown in FIG. 2, the attached end portion 3 is provided with a screw hole 4 extending in the vertical direction.

Reference numeral 5 denotes a vehicle body strength member extending in the longitudinal direction of the vehicle. As shown in FIG. The flange portion F is joined to form a closed cross-sectional structure. A mounting end 6 is provided at the distal end of the vehicle body strength member 5. The front side member 5 is located at the inner side of the mounting end 6 in the vehicle width direction.
The inner wall portion 6a is formed by the wall portion a. An outer vertical wall portion 6b is formed by a wall portion of the closing plate 5b at a portion of the mounting end portion 6 closer to the outer side in the vehicle width direction. Screw holes 7 are bored in the top and bottom parts of the mounting end 6.

The attached end portion 3 is provided with an inner abutting portion 3a at a portion facing the inner vertical wall portion 6a, and an outer abutting portion 3b at a portion facing the outer vertical wall portion 6b. There is.

The attached end 3 is inserted into the attaching end 6 so that the screw hole 4 and the screw hole 7 face each other, and is attached to the vehicle body strength member 5 via a bolt 8 and a nut 9 along the vertical direction. It is rotatably mounted.

As shown in FIG. 3, the inner vertical wall portion 6a of the mounting end portion 6 comes into contact with the inner abutting portion 3a of the attached end portion 3 when the bumper 1 is in a substantially straight state during a vehicle collision. It is bent inward in the vehicle width direction at a predetermined angle θ (see FIG. 1). This angle θ is the angle α formed between the longitudinal center line of the bumper 1 and the vehicle width direction, and the angle α between the longitudinal center line of the bumper 1 and the vehicle width direction, This is preset as the sum of the deflection angle β that occurs. Note that the deflection angle β can be estimated by calculation based on beam bending theory. Further, the bending starting point K of the inner vertical wall portion 6a is the intersection of a line in the vehicle width direction passing through the axial center of the bolt 8 and the wall portion of the front side member 5a.

The outer abutting portion 3b of the attached end portion 3 has a shape shown in FIG.
As shown in FIG.
An R-shape T is formed as a relief part so that it slides into contact with b without coming into contact with it. This R shape T is a circular arc centered on the axial center of the bolt 8.

Next, the operation of the automobile bumper mounting structure constructed as described above will be explained.

As shown in FIG. 3, when a vehicle has a frontal collision, the bumper 1 is in a substantially straight state, but as the bumper 1 deforms, the bumper stay 2 attached to the bumper 1 is moved in the vehicle width direction. Turn outward. Since the bumper stay 2 and the vehicle body strength member 5 are attached via bolts 8, the vehicle body strength member 5 bends outward in the vehicle width direction, and the bumper stay 2 tends to rotate around the axis of the bolt 8. be. Here, the inner contact portion 3a of the attached end portion 3
is set at a predetermined angle θ (Fig. 1
Since the bumper stay 2 is bent inward in the vehicle width direction at the angle (see ), the bumper stay 2 rotates inward in the vehicle width direction until the inner contact portion 3a and the inner vertical wall portion 6a abut against each other.

On the other hand, as shown in FIG. 3, the outer contact portion 3b of the attached end portion 3 is provided with a relief portion so as to slide into contact with the outer vertical wall portion 6b of the attachment end portion 6 without contacting it in the event of a vehicle collision. Since the R-shaped T is formed, this bumper stay 2
There is no restriction on inward rotation in the vehicle width direction.

Here, the impact force f transmitted from the bumper 1 to the vehicle body strength member 5 immediately after the collision is the force f1 transmitted to the vehicle body strength member 5 side via the bolt 8, and the force f1 transmitted to the vehicle body strength member 5 side via the bolt 8, and the force f1 transmitted to the body strength member 5 side via the bolt 8, The force f2 is transmitted to the vehicle body strength member through the contact portion with the vertical wall portion 6a. The former force f
1 causes a bending moment that bends the vehicle body strength member 5 outward in the vehicle width direction, and the latter force f2 causes the vehicle body strength member 5 to bend outward in the vehicle width direction.
This creates a bending moment that bends the vehicle inward in the vehicle width direction. The bending moments acting on the vehicle body strength member 5 due to the bending moments in these different directions are smaller than in the past, and the impact force f mainly acts in a direction that compresses the vehicle body strength member 5. Therefore, buckling of the vehicle body strength member 5 is suppressed, and as shown in FIG.
As shown in B), since the impact force can be absorbed by the collapse of the vehicle body strength member 5 due to compression, the impact absorption can be improved compared to the conventional technology without increasing the size of the vehicle body strength member 5. This is shown in the graph of FIG. In the figure, the broken line is the impact energy absorption curve of the vehicle body strength member in the conventional bumper mounting structure, and the solid line is the impact energy absorption curve of the vehicle body strength member in the bumper mounting structure according to the present invention. In other words, it is possible to absorb a larger amount of impact energy than before by the area of the shaded area.

Furthermore, when a slight impact force is applied in a light vehicle collision and the bumper 1 is deformed to a substantially straight state before the impact force is released, the attached end 3 of the bumper stay 2 The inner contact portion 3a of the vehicle body strength member 5 does not contact the inner contact portion of the vehicle body strength member 5, or even if the inner contact portion 3a contacts the vehicle body strength member 5, the inner contact portion 3a of the vehicle body strength member 5
Only a small force acts on it. Therefore, there is no damage to the vehicle body strength members, and it is only necessary to replace the bumper 1 or the fascia (not shown). In this embodiment, the bumper attachment structure at the front of the vehicle body has been described, but it goes without saying that a similar configuration can be applied to the bumper attachment structure at the rear of the vehicle body.

It is more effective if the bumper 1 (armature) is made of a resin material such as a PP material mixed with glass fiber.

[0024]

As described above, according to the automobile bumper mounting structure according to the present invention, the impact force caused by a collision can be absorbed by moving the vehicle body strength member outward in the vehicle width direction without increasing the size of the vehicle body strength member. A force that generates a bending moment that tends to deflect the vehicle body strength member, and a force that generates a bending moment that tends to deflect the vehicle body strength member inward in the vehicle width direction.
By making the resultant force a compressive load acting in the axial direction of the vehicle body strength member, it is possible to induce crushing of the vehicle body strength member and improve the amount of shock absorption.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an automobile bumper mounting structure according to the present invention.

FIG. 2 is a perspective view of an automobile bumper mounting structure according to the present invention.

FIG. 3 is an explanatory diagram of the operation of the automobile bumper mounting structure according to the present invention.

FIG. 4 is an explanatory diagram of the operation of the automobile bumper mounting structure according to the present invention.

FIG. 5 is a diagram comparing the impact force absorption performance of the automobile bumper mounting structure according to the present invention with the impact force absorption performance of a conventional automobile bumper mounting structure.

FIG. 6 is an explanatory diagram of a conventional automobile bumper mounting structure.

FIG. 7 is an explanatory diagram of a conventional automobile bumper mounting structure.

FIG. 8 is an explanatory diagram of a conventional automobile bumper mounting structure.

FIG. 9 is an explanatory diagram of a conventional automobile bumper mounting structure.

FIG. 10 is an explanatory diagram of the operation of a conventional automobile bumper mounting structure.

FIG. 11 is an explanatory diagram of the operation of a conventional automobile bumper mounting structure.

[Explanation of symbols]

1 Bumper 2 Bumper stay 3 Attached end portion 3a Inner contact portion 3b Outer contact portion 5a Front side member (vehicle body strength member) 5b
Closing plate (vehicle body strength member) 6 Mounting end 6a Inner standing wall 6b Outer standing wall 8 Bolt (vertical axis) T R shape (relief part) θ Predetermined angle

Claims (1)

[Claims] Claims: 1. A bumper mounting structure in which a substantially arcuate bumper is attached to a mounting end of a vehicle body strength member extending in the vehicle longitudinal direction via at least a pair of bumper stays, wherein the mounting end is attached to a mounting end of a vehicle body strength member extending in the vehicle longitudinal direction. It has an inner standing wall part closer to the inside and an outer standing wall part closer to the outside in the vehicle width direction, and has a cross-sectional shape in which an attached end of the bumper stay is inserted between the two standing walls, and the attached end The part has an inner abutting part facing the inner vertical wall part and an outer abutting part facing the outer vertical wall part, and the mounted end of the bumper stay is inserted into the mounting end of the vehicle body strength member. in a state where
It is rotatably attached via an axis in the vertical direction, and the inner vertical wall portion of the mounting end is such that the inner abutting portion of the attached end comes into contact when the bumper is in a substantially straight state in the event of a vehicle collision. The mounting end portion is bent at a predetermined angle so as to be in contact with the mounting end portion, and a relief portion is formed in the outer contact portion of the attached end portion to prevent the mounting end portion from coming into contact with the outer vertical wall portion of the mounting end portion in the event of a collision with the vehicle body. Bumper mounting structure.