JP7651515B2 - Vehicle impact absorbing components - Google Patents

Description

The present invention relates to a shock absorbing component for a vehicle.

Patent Document 1 describes an energy absorbing member. The energy absorbing member described in Patent Document 1 is formed by laminating multiple long fiber substrates. The long fiber substrate is formed by impregnating a reinforcing member made of multiple long fibers in a sheet shape with a matrix resin. The long fibers of the long fiber substrate cross at 90 degrees with the long fibers of other long fiber substrates adjacent to the long fiber substrate.

A cross section of each long fiber substrate perpendicular to the direction of energy input has a wave shape.
When a collision load is applied to the entire one end face of the energy absorbing member in a direction perpendicular to the same end face, peeling occurs between the long fiber substrates starting from each inflection point of the wave shape. In addition, the long fibers along the energy input direction are deformed, and the long fibers intersecting the long fibers at 90 degrees are broken. The collision energy is absorbed through such peeling and breaking.

JP 2010-138953 A

However, in the case of the energy absorbing member described in Patent Document 1, when a collision load is applied to the energy absorbing member, there is a risk that the locations where peeling occurs between the long fiber base materials may vary. As a result, the shock absorption properties of the energy absorbing member are not stable.

The vehicle impact absorbing component for solving the above problem has an end face configured to receive a collision load, and is provided with an inner part configured by welding together a plurality of fiber-reinforced resin layers formed by impregnating reinforcing fibers with a thermoplastic resin and stacking them in a stacking direction, two outer parts configured by welding together a plurality of fiber-reinforced resin layers formed by impregnating reinforcing fibers with a thermoplastic resin and stacking them in the stacking direction, sandwiching the inner part from both sides in the stacking direction, and two thermoplastic resin layers located between the inner part and the outer part and welded to the inner part and the outer part, respectively, and the direction perpendicular to the end face is perpendicular to the stacking direction.

FIG. 1 is a cross-sectional view of a shock absorbing member for a vehicle according to one embodiment. FIG. 2 is a perspective view of the vehicle impact absorbing member of FIG. FIG. 3 is an exploded perspective view of the shock absorbing member for a vehicle shown in FIG. FIG. 4 is a perspective cross-sectional view showing a layer structure of the main body of the impact absorbing member for a vehicle shown in FIG. FIG. 5 is a cross-sectional view of the main body of the vehicle impact absorbing member of FIG. 6(a) and 6(b) are cross-sectional views showing the operation of the impact absorbing member for a vehicle shown in FIG. FIG. 7 is an exploded perspective view of a laminate constituting the main body of the vehicle impact absorbing member of FIG. 8(a) and 8(b) are cross-sectional views showing a manufacturing process for the main body of the impact absorbing member for a vehicle shown in FIG. FIG. 9 is an exploded perspective view of a laminate constituting a main body of the impact absorbing member for a vehicle according to the first modified example. FIG. 10 is a cross-sectional view of a main body of a shock absorbing member for a vehicle according to a second modified example. FIG. 11 is a cross-sectional view of a main body of a shock absorbing member for a vehicle according to a third modified example. FIG. 12 is a cross-sectional view of a main body of a shock absorbing member for a vehicle according to a fourth modified example.

Hereinafter, one embodiment of a shock absorbing member for a vehicle (hereinafter, shock absorbing member 20) will be described with reference to FIGS. 1 to 8. FIG.
In the following description, the longitudinal direction of the vehicle is referred to as the longitudinal direction L, the width direction of the vehicle is referred to as the width direction W, and the vertical direction of the vehicle when the vehicle is positioned on a horizontal plane is referred to as the vertical direction Z.

In addition, the front and rear sides in the front-to-rear direction L will be referred to simply as the "front" and "rear", respectively, and the upper and lower sides in the vertical direction Z will be referred to simply as the "upper" and "lower", respectively.

As shown in FIG. 1, the front part of the vehicle is provided with, in order from the front side, a bumper reinforcement 10, a shock absorbing member 20, and a front side member 11. The shock absorbing member 20 is sandwiched between the bumper reinforcement 10 and the front side member 11 in the front-rear direction L.

As shown in Figures 1 to 3, the impact absorbing member 20 includes a fixed base 30 that is fixed to the front end surface of the front side member 11, and a main body portion 40 that is located between the fixed base 30 and the bumper reinforcement 10 and is fixed to the fixed base 30.

First, the main body 40 will be described.
The main body portion 40 has an end surface 41 that abuts against the rear surface of the bumper reinforcement 10. In other words, the main body portion 40 has the end surface 41 that is configured to receive a collision load.

The main body 40 comprises an inner portion 50, two outer portions 60 sandwiching the inner portion 50 from both sides in the stacking direction A, and two resin layers 80 positioned between each of the inner portion 50 and the outer portion 60.

The direction perpendicular to the end surface 41 and the stacking direction A are perpendicular to each other.
<Inner portion 50>
As shown in Fig. 4, the inner portion 50 is configured by welding a plurality of fiber reinforced resin layers 51 to each other and stacking them in a stacking direction A. The fiber reinforced resin layer 51 is made of long fibers extending in a single direction, and is formed by impregnating a plurality of reinforcing fibers 52 arranged in a sheet shape with a thermoplastic resin. The inner portion 50 has, for example, four fiber reinforced resin layers 51. The reinforcing fibers 52 are preferably glass fibers. The resin constituting the fiber reinforced resin layer 51 is preferably polypropylene.

It is preferable that the reinforcing fibers 52 of adjacent fiber reinforced resin layers 51 are perpendicular to each other.
<Outer portion 60>
As shown in FIG. 4, the outer portion 60 is configured by laminating a plurality of fiber-reinforced resin layers 61 that are welded together. The fiber-reinforced resin layer 61 is made of long fibers extending in a single direction, and is formed by impregnating a plurality of reinforcing fibers 62 arranged in a sheet shape with a thermoplastic resin. The fiber-reinforced resin layer 61 has the same configuration as the fiber-reinforced resin layer 51 that constitutes the inner portion 50. In this case, the number of fiber-reinforced resin layers 61 that constitute the outer portion 60 is preferably smaller than the number of fiber-reinforced resin layers 51 that constitute the inner portion 50. The outer portion 60 has, for example, two fiber-reinforced resin layers 61. The reinforcing fibers 62 are preferably glass fibers. The resin that constitutes the fiber-reinforced resin layer 61 is preferably polypropylene.

It is preferable that the reinforcing fibers 62 of adjacent fiber reinforced resin layers 61 are perpendicular to each other.
<Resin layer 80>
As shown in Fig. 4, the resin layer 80 is formed of a thermoplastic resin. The resin layer 80 is welded to each of the inner portion 50 and the outer portion 60. The resin constituting the resin layer 80 is preferably a resin having a higher elongation than the resin constituting the inner portion 50 and the resin constituting the outer portion 60. The resin constituting the resin layer 80 is preferably polypropylene.

As shown in FIG. 5, the shape of a cross section S1 of the main body 40 parallel to the end face 41 is uniform throughout in the front-rear direction L.
The shape of the cross section S1 is preferably an open cross-sectional shape.

The cross section S1 is preferably substantially W-shaped.
Next, the cross-sectional shape of the main body 40 of this embodiment will be described in detail.
As shown in Figure 5, cross section S1 has a first extension portion 43, a second extension portion 44, a third extension portion 45, a first connecting portion 46, a second connecting portion 47, a first side portion 48, and a second side portion 49, all of which extend in a straight line.

Here, two imaginary lines that are parallel to each other and are located on an imaginary plane V that includes the cross section S1 are defined as a first imaginary line V1 and a second imaginary line V2. In addition, a virtual line that is located on the imaginary plane V and perpendicular to the first imaginary line V1 and the second imaginary line V2 is defined as a third imaginary line V3.

The cross section S1 has a symmetric shape in the extending direction of the first virtual straight line V1.
The first extension portion 43 and the second extension portion 44 extend along the first virtual straight line V1 on the first virtual straight line V1 and are arranged at a distance from each other in the extension direction of the first virtual straight line V1 (the left-right direction in the same figure).

The third extension portion 45 extends along the second virtual straight line V2 on the second virtual straight line V2 and is located between the first extension portion 43 and the second extension portion 44 in the extension direction of the first virtual straight line V1.

The first connecting portion 46 connects the first end 43a of the pair of ends 43a, 43b of the first extending portion 43 that is closer to the third extending portion 45, and the first end 45a of the pair of ends 45a, 45b of the third extending portion 45 that is closer to the first extending portion 43. The first connecting portion 46 is inclined with respect to the third imaginary line V3 so that the closer it is to the third extending portion 45 in the extension direction of the third imaginary line V3 (the up-down direction in the figure), the further away it is from the first extending portion 43 in the extension direction of the first imaginary line V1.

The second connecting portion 47 connects the second end 44b of the pair of ends 44a, 44b of the second extending portion 44 that is closer to the third extending portion 45, and the second end 45b of the pair of ends 45a, 45b of the third extending portion 45 that is closer to the second extending portion 44. In more detail, the second connecting portion 47 is inclined with respect to the third imaginary line V3 so that the closer it is to the third extending portion 45 in the extension direction of the third imaginary line V3, the further away it is from the second extending portion 44 in the extension direction of the first imaginary line V1.

The first side portion 48 extends from the second end 43b opposite the first end 43a of the first extension portion 43 and faces the first connecting portion 46. The first side portion 48 is inclined with respect to the third virtual line V3 so that the closer it is to the third extension portion 45 in the extension direction of the third virtual line V3, the further it is from the first extension portion 43 in the extension direction of the first virtual line V1.

The second side portion 49 extends from the first end 44a opposite the second end 44b of the second extension portion 44 and faces the second connecting portion 47. The second side portion 49 is inclined with respect to the third virtual line V3 so that the closer it is to the third extension portion 45 in the extension direction of the third virtual line V3, the further it is from the second extension portion 44 in the extension direction of the first virtual line V1.

A tip 48a of the first side portion 48 and a tip 49a of the second side portion 49 are located on a second imaginary straight line V2.
Here, the length of the first extension portion 43 along the first imaginary straight line V1, the length of the second extension portion 44 along the first imaginary straight line V1, and the length of the third extension portion 45 along the second imaginary straight line V2 are respectively designated as W1, W2, and W3. In addition, the distance between the tip 48a of the first side portion 48 and the tip 49a of the second side portion 49, and the length of the cross section S1 along the third imaginary straight line V3 are respectively designated as W4 and H.

At this time, it is preferable that the following (Equation 1), (Equation 2), and (Equation 3) are established.
W4=H...(Formula 1)
W1=W2...(Formula 2)
W3/W1=1.1~1.4...(Formula 3)
In addition, in formula 3, it is more preferable that W3/W1=1.4.

As shown in FIGS. 2 and 3 , the fixed base 30 has a connecting plate 31 and a support portion 32 .
The connecting plate 31 extends in the vehicle width direction W and the up-down direction Z. The connecting plate 31 is provided with a plurality of holes 31a penetrating in the front-rear direction L. Bolts that connect the connecting plate 31 to the front end surfaces of the front side members 11 are inserted into the holes 31a.

The support portion 32 protrudes from the front surface of the connecting plate 31. A groove portion 32a is formed in the front surface of the support portion 32, into which the rear end portion of the main body portion 40 is inserted and fixed.
Next, a manufacturing procedure for the main body 40 of the impact absorbing member 20 will be described.

First, a strip-shaped raw material (not shown) is cut to a predetermined length to form the fiber reinforced resin layers 51, 61.
Moreover, a strip-shaped raw material (not shown) is cut to a predetermined length to form the resin layer 80 .

Next, as shown in FIG. 7, from the bottom up, two fiber-reinforced resin layers 61, one resin layer 80, four fiber-reinforced resin layers 51, one resin layer 80, and two fiber-reinforced resin layers 61 are stacked to form a laminate 90.

Next, as shown in FIG. 8( a ), the laminate 90 is heated and placed between a first die 101 and a second die 102 of a molding die 100 .
Next, as shown in FIG. 8B, the first die 101 is clamped to the second die 102, whereby the laminate 90 is press-molded.

Then, through a trimming step (not shown), the main body 40 is manufactured.
Next, the operation of this embodiment will be described.
As shown by the arrow in FIG. 6A , when a vehicle undergoes a frontal collision, a collision load is applied to the end surface 41 of the main body portion 40 of the impact absorbing member 20 .

Then, as shown in FIG. 6(b), the two resin layers 80, which are weaker than the fiber-reinforced resin layers 51, 61, break preferentially. As a result, peeling occurs between the inner portion 50 and the two outer portions 60, while the inner portion 50 buckles and the two outer portions 60 bend. In this way, according to this embodiment, the locations where peeling occurs are consistent.

Next, the effects of this embodiment will be described.
(1) The main body portion 40 of the impact absorbing member 20 is located between the inner portion 50 and the outer portion 60, and is provided with a thermoplastic resin layer 80 that is welded to the inner portion 50 and the outer portion 60, respectively.

With this configuration, the above-mentioned effects are achieved, and therefore the variation in the shock absorbing properties of the shock absorbing member 20 can be reduced.
(2) The shape of the cross section S1 parallel to the end surface 41 is an open cross-sectional shape.

With this configuration, the laminate 90, in which the inner portion 50, the two outer portions 60, and the two resin layers 80 are stacked, is heated and pressed to form the main body 40 of the shock absorbing member 20. This makes it easy to manufacture the main body 40, and therefore the shock absorbing member 20.

(3) Because the main body 40 of the shock absorbing member 20 has a W-shaped cross section, the perimeter of the cross section of the shock absorbing member 20 can be made longer than if the cross section were U-shaped. This improves the cross-sectional strength and cross-sectional efficiency.

(4) W4=H, W1=W2, and W3/W1=1.1 to 1.4.
In the impact absorbing member 20 having a W-shaped cross section where W4=H and W1=W2, the cross-sectional strength is maximum when W3/W1 is in the range of 1.1 to 1.4, and the cross-sectional strength decreases as W3/W1 deviates from the range of 1.1 to 1.4.

Therefore, by setting W3/W1 to 1.1 to 1.4, the cross-sectional strength of the impact absorbing member 20 having a W-shaped cross section where W4 = H and W1 = W2 can be maximized.

<Example of change>
This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

The fixing base 30 may be omitted, and the main body 40 may be directly fixed to the front end surface of the front side member 11 .
The relationship W1>W2 may be satisfied, or W1<W2 may be satisfied. In other words, the cross section S1 may have an asymmetric shape in the extending direction of the first virtual straight line V1.

The positions of the tip 48a of the first side portion 48 and the tip 49a of the second side portion 49 may be set at positions away from the first extension portion 43 and the second extension portion 44 with respect to the second virtual straight line V2.
The shape of the cross section S1 may be U-shaped as shown in Fig. 10 or S-shaped as shown in Fig. 11. The shape of the cross section S1 may be zigzag as shown in Fig. 12.

The shape of the cross section S1 parallel to the end surface 41 may be a closed cross-sectional shape.
As shown in FIG. 9 , the inner portion 50 and the outer portion 60 may include a portion in which the reinforcing fibers 52 (62) of adjacent fiber reinforced resin layers 51 (61) are parallel to each other.

The reinforcing fibers 52 and 62 may be carbon fibers.
Although polypropylene is used as the resin forming the inner portion 50, the outer portion 60, and the resin layer 80, other thermoplastic resins including polyamides such as nylon 6 can be used.

10... bumper reinforcement 11... front side member 20... impact absorbing member (vehicle impact absorbing member)
30... Fixing base 31... Connection plate 31a... Hole 32... Supporting part 32a... Groove part 40... Main body part 41... End face 43... First extending part 43a... First end 43b... Second end 44... Second extending part 44a... First end 44b... Second end 45... Third extending part 45a... First end 45b... Second end 46... First connection part 47... Second connection part 48... First side part 49... Second side part 50... Inner part 51... Fiber reinforced resin layer 52... Reinforced fiber 60... Outer part 61... Fiber reinforced resin layer 62... Reinforced fiber 80... Resin layer 90... Laminated body 100... Molding mold 101... First mold 102... Second mold

Claims (3)

A vehicle shock absorbing member having an end surface configured to receive a collision load,
An inner portion configured by welding a plurality of fiber reinforced resin layers formed by impregnating reinforced fibers with a thermoplastic resin to each other and stacking them in a stacking direction;
A plurality of fiber-reinforced resin layers formed by impregnating reinforcing fibers with a thermoplastic resin are welded to each other and stacked in the stacking direction, and two outer parts sandwiching the inner part from both sides in the stacking direction;
two thermoplastic resin layers located between the inner portion and the outer portion and welded to the inner portion and the outer portion, respectively;
a direction perpendicular to the end surface and the stacking direction are perpendicular to each other,
The resin layer does not contain the reinforcing fibers .
Impact absorbing components for vehicles. The shape of a cross section parallel to the end surface is an open cross-sectional shape.
The shock absorbing member for a vehicle according to claim 1 . The cross section is
a first extension portion and a second extension portion that extend along a first virtual line on a virtual plane including the cross section and are spaced apart from each other in an extension direction of the first virtual line;
a third extension portion that extends along a second virtual line parallel to the first virtual line on the virtual plane and is located between the first extension portion and the second extension portion in the extension direction of the first virtual line;
a first connecting portion connecting a first end of the pair of ends of the first extension portion that is closer to the third extension portion and a first end of the pair of ends of the third extension portion that is closer to the first extension portion;
a second connecting portion connecting a second end of the pair of ends of the second extension portion closer to the third extension portion and a second end of the pair of ends of the third extension portion closer to the second extension portion;
a first side portion extending from a second end of the first extension portion opposite the first end and facing the first connection portion;
a second side portion extending from a first end of the second extension portion opposite the second end and facing the second connection portion;
The shape is symmetrical in the extending direction of the first virtual straight line.
The shock absorbing member for a vehicle according to claim 2 .

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