JP7776408B2 - Vehicle impact absorbing components - Google Patents

Description

The present invention relates to an impact absorbing member for a vehicle.

Patent Document 1 discloses an energy absorption structure for a hollow cylindrical body made of metal or resin that is subjected to a compressive load. The hollow cylindrical body has a trigger, a hollow cylindrical portion, and multiple grooves. The trigger is located at the open end of the hollow cylindrical body and is inclined so that the closer it is to the open end, the more it is positioned toward the outer periphery. The hollow cylindrical portion is connected to the trigger on the side opposite the open end. The multiple grooves extend along the axial direction in the trigger and hollow cylindrical portion and are spaced apart from one another in the circumferential direction. The portions of the grooves formed in the hollow cylindrical portion do not penetrate the hollow cylindrical portion in the thickness direction.

When an axial load is applied to the hollow cylinder, a bending moment acts on the hollow cylindrical portion, and a tensile force acts in the circumferential direction to push open the groove. This causes cracks to form in the grooves of the hollow cylindrical portion. These cracks progress in the axial direction due to the action of the axial load. Furthermore, the trigger is bent from the open end toward the outer periphery by the action of the bending moment, causing it to deform in a spiral shape. In this way, energy is absorbed by the spiral deformation and the progression of the crack.

Japanese Patent Application Publication No. 10-19074

In the hollow cylindrical body described in Patent Document 1, the initial load increases rapidly when an axial load is applied, making the hollow cylindrical portion prone to buckling. Therefore, there is room for improvement in terms of energy absorption performance.

The vehicle impact absorbing component that solves the above problem has a main body portion extending in a first direction and a receiving portion that covers the tip of the main body portion in the first direction and receives the collision load, and the receiving portion has lower rigidity than the main body portion.

FIG. 1 is a cross-sectional view of an impact absorbing member for a vehicle according to an embodiment. FIG. 2 is a perspective view of the vehicle impact absorbing member of FIG. FIG. 3 is a perspective view of the vehicle impact absorbing member of FIG. FIG. 4 is a perspective cross-sectional view showing the layer structure of the main body of the impact absorbing member for a vehicle shown in FIG. FIG. 5(a) is a cross-sectional view of the impact absorbing member before deformation, and FIG. 5(b) is a cross-sectional view of the impact absorbing member after deformation. FIG. 6 is a graph showing the relationship between the displacement and the load of the impact absorbing members of this embodiment and the comparative example. FIG. 7 is a graph showing the relationship between the displacement and the load of the impact absorbing members of this embodiment and the comparative example. FIG. 10 is a perspective view of a first modified example of an impact absorbing member for a vehicle. FIG. 10 is a perspective view of a second modified example of an impact absorbing member for a vehicle. FIG. 10 is a perspective view of a shock absorbing member for a vehicle according to a third modified example.

Hereinafter, one embodiment of a shock absorbing member for a vehicle (hereinafter referred to as a shock absorbing member 20) will be described with reference to FIGS.
Hereinafter, the longitudinal direction of the vehicle will be referred to as the longitudinal direction L, the direction of the vehicle will be referred to as the vehicle width direction W, and the vertical direction of the vehicle when the vehicle is positioned on a horizontal plane will be referred to as the vertical direction Z. Furthermore, the front and rear sides in the longitudinal direction L will be referred to simply as the "front side" and the "rear side", respectively, and the upper and lower sides in the vertical direction Z will be referred to simply as the "upper side" and the "lower side", respectively.

As shown in FIG. 1, the front of the vehicle is provided with, in order from the front, a bumper reinforcement 10, an impact absorbing member 20, and a front side member 11. That is, the impact absorbing member 20 is sandwiched between the bumper reinforcement 10 and the front side member 11 in the fore-and-aft direction L.

As shown in Figures 1 to 3, the impact absorbing member 20 has a main body portion 40 extending in a first direction and a receiving portion 50 that covers the tip of the main body portion 40 in the first direction and receives a collision load. The receiving portion 50 has lower rigidity than the main body portion 40. In this embodiment, the front-to-rear direction L corresponds to the first direction in [Means for Solving the Problems]. The impact absorbing member 20 also has a base portion 30 and a connecting portion 60.

Each component of the impact absorbing member 20 will be described in detail below.
<Main body 40>
4, the main body 40 is preferably in the form of a plate in which a plurality of fiber-reinforced resin layers 41 formed by impregnating reinforcing fibers 42 with resin 43 are stacked on one another in a plane direction perpendicular to the first direction (front-rear direction L). The main body 40 also preferably has a bent portion 44 that is bent in the plane direction.

The fiber-reinforced resin layer 41 is formed by impregnating a plurality of reinforcing fibers 42 arranged in a sheet shape with a thermoplastic resin 43. The plurality of reinforcing fibers 42 that make up the fiber-reinforced resin layer 41 are long fibers that extend in a single direction.

The reinforcing fibers 42 are preferably glass fibers, and the resin 43 is preferably polypropylene or nylon.
The plurality of fiber reinforced resin layers 41 are welded to one another. It is preferable that the reinforcing fibers 42 of adjacent fiber reinforced resin layers 41 extend perpendicular to one another.

The cross section of the main body 40 in the above-mentioned plane direction is preferably an open cross section.
2 and 3, the cross-sectional shape of the main body 40 in the above-mentioned planar direction is the same throughout the first direction (front-rear direction L). The cross-sectional shape of the main body 40 in this embodiment is approximately W-shaped. The main body 40 has a total of six bent portions 44a to 44f.

<Receiving portion 50>
1 to 3, the receiving portion 50 extends along the tip, i.e., the front end, of the main body portion 40. The receiving portion 50 is preferably provided over the entire extension direction of the tip of the main body portion 40. The receiving portion 50 in this embodiment is substantially W-shaped.

The receiving portion 50 has a cross-sectional shape that tapers toward the tip in the first direction, i.e., toward the front. Specifically, the receiving portion 50 has a tip surface 51 located at one end of the body portion 40 in the thickness direction, and an inclined surface 52 that continues to the other end of the tip surface 51 in the thickness direction. The tip surface 51 is located on a plane perpendicular to the first direction (front-to-back direction L). In this embodiment, the tip surface 51 is located on the outside of the W shape in the thickness direction.

The receiving portion 50 is preferably made of a thermoplastic resin, for example, the same as the resin 43.
<Base portion 30>
1 to 3, the base portion 30 is provided at the base end of the main body portion 40 in the first direction, i.e., at the rear end of the main body portion 40. The base portion 30 is preferably made of the same resin as the receiving portion 50.

The pedestal portion 30 has a base portion 31 , a support protrusion 32 , and a collar 34 .
The base portion 31 has a substantially rectangular plate shape.
The support protrusion 32 protrudes forward from the front surface of the base portion 31. The support protrusion 32 has a groove portion 33 in which the rear end portion of the main body portion 40 is received and fixed (see FIG. 1).

The base portion 31 and the support protrusion 32 are integrally molded from the above-mentioned resin.
Cylindrical collars 34 that penetrate in the front-rear direction L are integrally provided at the four corners of the base portion 31. Bolts (not shown) for fixing the pedestal portion 30 to the front end surfaces of the front side members 11 are inserted into the collars 34.

<Connection part 60>
2 and 3 , the connecting portion 60 connects the base portion 30 and the receiving portion 50. The connecting portion 60 is provided on the surface of the main body portion 40. The connecting portion 60 is preferably made of the same resin as the receiving portion 50.

The connecting portion 60 of this embodiment has two first connecting portions 61 and three second connecting portions 62 .
The first connecting portions 61 are provided at both ends of the extending direction of the main body portion 40 in the plane direction. The two first connecting portions 61 extend in the first direction.

One second connecting portion 62 is provided on each of the outer surfaces of the W-shape between bent portions 44a and 44b of the main body portion 40, between bent portions 44c and 44d of the main body portion 40, and between bent portions 44e and 44f of the main body portion 40. The three first connecting portions 61 extend in the first direction.

Next, a manufacturing procedure for the impact absorbing member 20 of this embodiment will be described.
First, the manufacturing procedure for the main body 40 will be described.
A laminate is formed by welding the plurality of fiber-reinforced resin layers 41 together. Then, the laminate is heated and pressed with a press mold (both not shown), thereby forming the main body 40 having a bent portion 44 that is bent in the planar direction.

Next, with the main body 40 and collar 34 inserted into the mold, molten resin (all not shown) is injected into the cavity formed by the molding surface of the mold and the main body 40 and collar 34. This results in the base 30, connecting portion 60, and receiving portion 50 being integrally molded onto the surface of the main body 40.

Next, the operation of this embodiment will be described.
When a vehicle collides head-on, the load associated with the collision (hereinafter referred to as the collision load) acts on the receiving portion 50 via the bumper reinforcement 10. Here, since the tip of the main body portion 40 is covered by the receiving portion 50, which has lower rigidity than the main body portion 40, the receiving portion 50 creates a starting point for fracture in the main body portion 40. As a result, the initial load when the collision load is received is reduced compared to when the tip of the main body portion 40 is not covered by the receiving portion 50. This makes it possible to suppress buckling of the main body portion 40.

Here, because the cross section of the main body portion 40 in the above-mentioned plane direction is an open cross section, the main body portion 40 deforms so as to open outward from the state shown in FIG. 5(a) to the state shown in FIG. 5(b). Note that the receiving portion 50 is not shown in FIG. 5(b).

Next, with reference to FIGS. 6 and 7, the results of a compression test on the relationship between displacement and load for the impact absorbing member 20 of this embodiment and an impact absorbing member of a comparative example will be described.
In Fig. 6, the load-displacement curve of the impact absorbing member 20 of this embodiment in a room temperature environment is shown by a solid line. Also in Fig. 6, the load-displacement curve of the impact absorbing member of the comparative example in a room temperature environment is shown by a dashed line. Also in Fig. 6, the load-displacement curve of the impact absorbing member of the comparative example when buckling occurs in a room temperature environment is shown by a dashed line. The impact absorbing member of the comparative example differs from the impact absorbing member of this embodiment in that it does not have the receiving portion 50 or the connecting portion 60.

As shown in FIG. 6, the impact absorbing member 20 of this embodiment can be said to reduce the initial load to about half that of the impact absorbing member of the comparative example.
In Figure 7, the load-displacement curve of the impact absorbing member 20 of this embodiment in a low-temperature environment is shown by a solid line. Also in Figure 7, the load-displacement curve of the impact absorbing member of the comparative example in a low-temperature environment is shown by a dashed line. Also in Figure 7, the load-displacement curve of the impact absorbing member of the comparative example in a normal temperature environment is shown by a broken line. The impact absorbing member of the comparative example differs from the impact absorbing member of this embodiment in that it does not have a receiving portion 50. Here, the low temperature in a low-temperature environment is minus 30 degrees. The normal temperature in a normal temperature environment is 23 degrees.

As shown in Figure 7, when comparing the load-displacement curve of the comparative example in a low-temperature environment with the load-displacement curve of the comparative example in a room-temperature environment, it can be said that the initial load is greater in a low-temperature environment than in a room-temperature environment. In contrast, with the impact absorbing member 20 of this embodiment, it can be said that the initial load is reduced compared to the impact absorbing member of the comparative example in a room-temperature environment.

Next, the effects of this embodiment will be described.
(1) The impact absorbing member 20 has a main body 40 extending in a first direction and a receiving portion 50 that covers the tip of the main body 40 in the first direction and receives a collision load. The receiving portion 50 has lower rigidity than the main body 40.

With this configuration, the tip of the main body 40 is covered by the receiving portion 50, which has lower rigidity than the main body 40. Therefore, when a collision load acts on the receiving portion 50, the receiving portion 50 becomes the starting point of destruction in the main body 40. As a result, the initial load when a collision load is applied is reduced compared to when the tip of the main body 40 is not covered by the receiving portion 50. This makes it possible to prevent the main body 40 from buckling. Therefore, energy absorption performance can be improved.

(2) The main body portion 40 is in the form of a plate in which multiple fiber-reinforced resin layers 41 formed by impregnating reinforcing fibers 42 with resin 43 are stacked on top of each other in a plane direction perpendicular to the first direction, and has bent portions 44 that are bent in the plane direction. The cross section of the main body portion 40 in the plane direction is an open cross section.

With this configuration, the cross section of the main body 40 in the planar direction is an open cross section, so that when subjected to a collision load, the main body 40 deforms and opens outward. This increases the amount of displacement of the main body 40 in the first direction when subjected to a collision load, i.e., the stroke. This further improves energy absorption performance.

(3) The receiving portion 50 has a cross-sectional shape that tapers toward the tip end in the first direction.
With this configuration, when a collision load acts on the tip of the receiving portion 50, the main body 40 deforms in the thickness direction of the main body 40 toward the side where the tip of the receiving portion 50 is located. This promotes the deformation of the main body 40 so that it opens outward, thereby further improving the energy absorption performance.

(4) The receiving portion 50 is made of a thermoplastic resin.
According to this configuration, the receiving portion 50 can be formed by insert molding, eliminating the need for a step of attaching the receiving portion 50 to the main body 40. Therefore, the impact absorbing member 20 can be easily formed.

(5) The base portion 30 is provided at the base end of the main body portion 40 in the first direction and is made of the same resin as the receiving portion 50. It also has a connecting portion 60 that connects the base portion 30 and the receiving portion 50 and is made of the same resin as the receiving portion 50. The connecting portion 60 is provided on the surface of the main body portion 40.

This configuration allows the base portion 30 and the receiving portion 50 to be formed simultaneously by insert molding. Furthermore, because the base portion 30 and the receiving portion 50 are connected via the connecting portion 60, the receiving portion 50 can be firmly fixed to the main body portion 40 and the base portion 30.

<Example of change>
The above embodiment can be modified as follows: The present embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

Either the first connecting portion 61 or the second connecting portion 62 may be omitted.
Both the first connecting portion 61 and the second connecting portion 62, i.e., the connecting portion 60, may be omitted.

The receiving portion 50 may be made of a material other than resin, such as rubber. In short, the receiving portion 50 may be made of any material as long as it has lower rigidity than the main body portion 40.
8, the tip surface 151 of the receiving portion 150 may be provided on the inside of the W-shape in the plate thickness direction. The receiving portion 150 has an inclined surface 152 on the opposite side of the tip surface 151 in the plate thickness direction of the main body 40.

- The receiving portion 50 is not limited to having a cross-sectional shape that tapers toward the tip in the first direction. For example, as shown in FIG. 9, the tip surface 251 of the receiving portion 250 may have a notch 253 in the portion that overlaps with the bent portions 44a to 44f in the first direction. In this case, the notch 253 in the tip surface 251 of the receiving portion 250 becomes the starting point of fracture, promoting deformation of the main body portion 40 so that it opens outward. This further improves energy absorption performance.

As shown in FIG. 10, the thickness of the receiving portion 350 in the first direction may be increased toward the center of the W-shape in the width direction.
In the above embodiment and each modified example, the cross-sectional shape of the main body portion 40 is exemplified as being W-shaped with two Vs lined up, but the cross-sectional shape of the main body portion can also be a "VVV" shape with three or more Vs lined up, or can be appropriately changed to a V-shape, U-shape, etc.

In the above embodiment and each modified example, the bent portion is embodied as the bent portion 44, but the bent portion may not be bent.
The cross section of the main body in the plane direction may be a closed cross section such as a circle.

Each of the above embodiments includes the configurations described in the following supplementary notes.
[Appendix 1]
An impact absorbing member for a vehicle, comprising: a plate-shaped main body portion extending in a first direction; and a receiving portion covering the tip of the main body portion in the first direction and receiving a collision load, wherein the receiving portion has lower rigidity than the main body portion.

[Appendix 2]
The main body portion is a plate-like member in which a plurality of fiber-reinforced resin layers formed by impregnating reinforcing fibers with resin are stacked on top of each other, and has a bent portion that is curved in a planar direction perpendicular to the first direction, and a cross section of the main body portion in the planar direction is an open cross section. [Appendix 1] An impact absorbing member for a vehicle.

[Appendix 3]
The bending portion is a bending portion having a shape bent in the planar direction, and the tip surface of the receiving portion has a notch in the portion overlapping with the bending portion in the first direction. [Appendix 2] An impact absorbing member for a vehicle described in.

[Appendix 4]
The impact absorbing member for a vehicle according to [Appendix 2] or [Appendix 3], wherein the receiving portion is tapered toward the tip end in the first direction as it extends further outward from the open cross section.

[Appendix 5]
The impact absorbing member for a vehicle according to any one of [Appendix 2] to [Appendix 4], wherein the receiving portion is made of resin.

[Appendix 6]
An impact absorbing member for a vehicle as described in [Appendix 5], comprising: a base portion provided at the base end of the main body portion in the first direction and made of the same resin as the receiving portion; and a connecting portion connecting the base portion and the receiving portion and made of the same resin as the receiving portion, wherein the connecting portion is provided on the surface of the main body portion.

DESCRIPTION OF SYMBOLS 10... Bumper reinforcement 11... Front side member 20... Impact absorbing member 30... Base portion 31... Plate portion 32... Support protrusion 33... Groove portion 34... Collar 40... Main body portion 41... Fiber reinforced resin layer 42... Reinforced fiber 43... Resin 44a to 44f... Bent portion 50, 150, 250, 350... Receiving portion 51, 151, 251... Tip surface 52, 152... Inclined surface 60... Connecting portion 61... First connecting portion 62... Second connecting portion 253... Notch portion

Claims (3)

a main body portion extending in a first direction;
a receiving portion that covers a tip of the main body portion in the first direction and receives a collision load,
the receiving portion has lower rigidity than the main body portion,
The main body portion has a plate shape in which a plurality of fiber-reinforced resin layers formed by impregnating reinforcing fibers with resin are stacked on each other in a plane direction perpendicular to the first direction, and has a bending portion having a shape bent in the plane direction,
a cross section of the main body in the planar direction is an open cross section,
The bent portion is a bent portion having a shape bent in the surface direction,
a tip end surface of the receiving portion having a notch at a portion overlapping the bent portion in the first direction ;
Impact absorbing components for vehicles. a main body portion extending in a first direction;
a receiving portion that covers a tip of the main body portion in the first direction and receives a collision load,
the receiving portion has lower rigidity than the main body portion,
The main body portion has a plate shape in which a plurality of fiber-reinforced resin layers formed by impregnating reinforcing fibers with resin are stacked on each other in a plane direction perpendicular to the first direction, and has a bending portion having a shape bent in the plane direction,
a cross section of the main body in the planar direction is an open cross section,
the receiving portion is made of a thermoplastic resin,
a base portion provided at a base end of the main body portion in the first direction and made of the same resin as the receiving portion;
a connecting portion that connects the base portion and the receiving portion and is made of the same resin as the receiving portion,
The connecting portion is provided on the surface of the main body portion .
Impact absorbing components for vehicles. The receiving portion has a cross-sectional shape that tapers toward a tip end in the first direction.
The impact absorbing member for a vehicle according to claim 1 or 2.