JP2726706B2 - Vehicle bumper device provided with FRP member - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle bumper device provided with an FRP member having a shock absorbing function.

[Related Art] In a bumper device used for a vehicle such as an automobile, the use of an FRP member as one means for improving shock absorbing performance has been studied. For example, in the prior art illustrated in FIG. 15, between the member 1 on the vehicle body side and the bumper body 2,
FRP member 3 with small radius of curvature formed in U or J shape
Is provided. One end 3a of the FRP member 3 is fixed to the vehicle body-side member 1 by a fastening part 4 such as a bolt.
The other end 3b of the bumper body 2 is
Is bound to.

In this type of bumper device, when a large load is applied to the bumper body 2 from the direction of arrow F (the front-rear direction of the vehicle body) due to a collision or the like, the impact is reduced by bending the FRP member 3. .

[Problems to be Solved by the Invention] In the above-mentioned bumper device, when various tests and the like for evaluating the performance were performed, the FRP member 3 having a small curvature radius and a large spring constant was found to have a load-deflection characteristic as designed and a predetermined value. In some cases could not exhibit the energy absorption performance. That is, when a large load in the F direction is applied to the FRP member 3, as the flexure of the FRP member 3 increases, the shear stress (stress in the direction along the reinforcing fibers) of the FRP member 3 becomes excessive, and interlayer shear fracture occurs. In some cases, the reaction force was abnormally increased before the FRP member 3 reached a predetermined flexure, and the vicinity of the mounting portion of the FRP member 3 and the fixing parts were damaged. Interlaminar shear fracture of the FRP member 3 is most remarkably observed at the center in the thickness direction of the FRP member 3.

After examining the cause of the above problem, the 3
It was found that both a and 3b were restrained in the vehicle width direction, which was a major factor.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a bumper device provided with an FRP member capable of exhibiting the original shock absorbing performance when the FRP member having a shock absorbing function receives a large load at the time of a collision or the like.

Means for Solving the Problems A bumper device developed by the present inventor to achieve the above object is formed into a substantially U- or J-shaped curved shape, one end of which is connected to a member on the vehicle body side and the other. FR whose end is connected to the bumper body and which bends in a direction to decrease the radius of curvature when a load along the front-rear direction of the vehicle body is applied to the bumper body
P member, provided between at least one of the FRP member and the bumper body or between the FRP member and the vehicle body side member, when the FRP member is bent in the above direction,
A lateral displacement absorbing mechanism that allows the RP member to be displaced in a direction intersecting the front-rear direction of the vehicle body.

[Operation] When a load is applied to the bumper body along the longitudinal direction of the vehicle body due to a collision or the like, the FRP member bends in a direction in which the radius of curvature is reduced. When the FRP member bends in the above direction, a part of the FRP member is slightly displaced also in a direction intersecting the longitudinal direction of the vehicle body. Since the FRP member used in the bumper device of the present invention is supported so that at least one end thereof can be displaced in the vehicle width direction or the like by the lateral displacement absorbing mechanism, the FRP member absorbs the lateral displacement generated in the FRP member. FRP members are mainly used for bending stress. For this reason, the occurrence of excessive shear stress or the like that causes the FRP member to be broken is suppressed, and the FRP member can exhibit predetermined performance according to design specifications.

[Embodiment] FIGS. 1 to 3 show a first embodiment of the present invention.
This will be described with reference to the drawings. Bumper device illustrated in FIG.
10 is a pair of left and right shock absorbers that also serve as bumper mounting stays
An FRP member 11 is provided. The bumper device 10 includes an FRP member 11 fixed to an end of a side member 12 as an example of a vehicle-side member, a bumper body 13 called an armature disposed on a front side of the FRP member 11, and A synthetic resin fascia 14 that covers the bumper body 13 and the like are provided. 15 is a tire. The bumper body 13 is a molded product made of fiber reinforced plastic as an example,
Press-formed sheet metal may be used. A pair of left and right convex portions 16 protruding toward the FRP member 11 is integrally provided on the rear surface side of the bumper main body 13.

The FRP member 11 is substantially U-shaped by a unidirectional reinforcing fiber 20 (only a part is shown) along a longitudinal direction and a well-known matrix resin 21.
Or J-shaped. The radius of curvature of the FRP member 11 is, for example, about 60 mm. Although a glass fiber bundle is used for the unidirectional reinforcing fibers 20, a carbon fiber bundle or an organic fiber bundle may be used in some cases. One end of the FRP member 11, that is, the vehicle-body-side mounting end 11a is fixed to the side member 12 by a fastening part 22 such as a bolt.

The FRP member 11 is used so as to receive a load F along the direction in which the radius of curvature decreases, that is, the longitudinal direction of the vehicle body. As an example, two FRP members 11, 11
The spring constant k of one FRP member 11 required to absorb 328 kgm of energy at a vehicle speed of 8 km / h at 1300 kg with a stroke of 50 mm is as large as 130 kgf / mm.

A bumper main body 13 is attached to the other end of the FRP member 11, that is, a free end 11b via a lateral displacement absorbing mechanism 30. As shown in FIG. 2, the lateral displacement absorbing mechanism 30 has a metal plate holder 31 having a U-shaped cross section when viewed from the side.
And a friction member 32 made of a rubber-like elastic body press-fitted between the inner surface of the holder 31 and the FRP member 11, and coupling parts 33 and 34 made of pins or bolts for attaching to the holder 31 and the bumper body 13. And the like. Holder 31
, The front end 16a of the convex portion 16 of the bumper body 13 is in contact with the front side of the FRP member 11. The FRP member 11 also serves as a stay for attaching the bumper body 13 to the side member 12.

Next, the operation of the bumper device 10 having the above configuration will be described.

Under normal use conditions (non-collision), the bumper body 13
Is restrained at a predetermined position via the FRP member 11, the holder 31, and the friction member 32, so that the bumper body 13 does not move carelessly.

When a large load F is applied to the bumper body 13 due to a collision or the like, the FRP member is connected to the bumper body 13 via the projection 16 and the connecting parts 33 and 34.
The force to bend 11 from the front is input. By this force
The FRP member 11 bends in a direction in which the radius of curvature is reduced, and the unidirectional reinforcing fibers 20 and the matrix resin 21 cooperate to store energy. The vehicle body side mounting end 11a of the FRP member 11 is a side member 12
When the FRP member 11 bends in the above direction, the free end 11b of the FRP member 11 tends to be displaced to some extent in the vehicle width direction. The displacement in this direction is absorbed by the lateral displacement absorbing mechanism 30. That is, since the FRP member 11 is relatively movable in the vehicle width direction with respect to the holder 31 via the friction member 32, the displacement of the FRP member 11 in the above direction is allowed. Therefore, the FRP member 11 is mainly subjected to bending in the longitudinal direction of the vehicle body, and it is possible to suppress the generation of stress in the direction along the reinforcing fibers 20 that causes interlayer shear failure.

4 and 5 show a second embodiment of the present invention.
The lateral displacement absorbing mechanism 30 of this embodiment is held by the holder 40 having a shape in which the free end 11b side of the FRP member 11 is closed in a B shape,
The holder 40 is drawn toward the bumper body 13 by a connecting part 41 such as a bolt, and is tightened.
The FRP member 11 is connected. The other end, that is, the fixed end side, of the FRP member 11 is fixed to a member (side member or the like) on the vehicle body side using fixing parts such as bolts, similarly to the first embodiment. Also in the second embodiment, when the FRP member 11 bends in the longitudinal direction of the vehicle body, the free end 11b side of the FRP member 11 can be allowed to be displaced in the vehicle width direction. Note that a friction member 32 similar to that described in the first embodiment may be interposed between the holder 40 and the FRP member 11.

6 and 7 show a third embodiment of the present invention.
In this embodiment, the FRP member 11 is attached to the bumper body 13 by sandwiching the free end 11b side between the protrusion 16 of the bumper body 13 and the holder 45. For the holder 45, a pin-shaped component or a bolt, a part of the bumper body 13, or the like is used. The fixed end side of the FRP member 11
It is fixed to a member on the vehicle body side as in the first embodiment. In addition,
Between the FRP member 11 and the convex portion 16, and between the FRP member 11 and the holder 45
Between them, a friction member 32 similar to that described in the first embodiment may be interposed.

In the fourth embodiment of the present invention shown in FIG.
By providing a lateral displacement absorbing mechanism 30 at the vehicle body side mounting end 11a of the P member 11, the mounting end 11a can be displaced in the vehicle width direction. That is, in this embodiment, the mounting end 11a of the FRP member 11 is held by a metal plate holder 50, and the holder 50 is fixed to the side member 12 by a fixing part 51 such as a bolt. A friction member 32 made of a rubber-like elastic body is press-fitted between the holder 50 and the FRP member 11. The other end side of the FRP member 11 is restricted to the bumper body 13 by pins and brackets as in the conventional product,
Alternatively, a lateral displacement absorbing mechanism similar to the first to third embodiments.
Install via 30. In the case of the fourth embodiment, the FRP member 1
The displacement in the vehicle width direction that occurs in a part of the FRP member 11 when the member 1 is bent in the longitudinal direction of the vehicle body is absorbed between the holder 50 and the mounting end 11a via the friction member 32. For this reason, as in each of the above embodiments, the FRP member 11 mainly acts on the bending stress, and the FRP
It is possible to suppress the occurrence of excessive shear stress that may cause the member 11 to break.

The lateral displacement absorbing mechanism 30 of the fifth embodiment shown in FIG.
Is provided with a long hole 53 in the vehicle width direction in the bumper body 13 and a pin 54 provided at the free end 11b of the FRP member 11 with the long hole 53.
The free end 11b can also be displaced in the vehicle width direction when the FRP member 11 bends in the front-rear direction. The pin 54 is fixed to the FRP member 11 by a plate 55.

It should be noted that, instead of providing the long hole 53, a portion extending over a length l
The portion 56 may be made thinner than the other portions, and the pin 54 may move in the 1 direction while breaking the thin portion 56 at the time of collision to absorb the lateral displacement. By doing so, the relative position between the free end 11b of the FRP member 11 and the bumper main body 13 can be reliably regulated, which is effective in preventing the occurrence of "play" in the mounting.

Also, as in the sixth embodiment shown in FIG.
May be positioned on the front side in the thickness direction of the FRP member 11 so that the plate 55 is less likely to be deformed when a load for bending the FRP member 11 is applied via the pin 54.

FIG. 11 to FIG. 13 show a seventh embodiment of the present invention. In this embodiment, the FRP member 11 is mounted on the side member 12 via the spacer 59 so that the vehicle body side mounting end 11a of the FRP member 11 can be inclined to some extent in the front-rear direction of the vehicle body, and between the FRP member 11 and the side member 12. An auxiliary shock absorber 60 is interposed. The auxiliary shock absorber 60 is made of a metal or FRP pipe or the like. As shown in FIG. 12, a load F is applied to the FRP member 11.
When the FRP member 11 is loaded, the mounting end 11a of the FRP member 11 warps backward and tilts to some extent, thereby absorbing the displacement of the free end 11b in the vehicle width direction, and the auxiliary shock absorber 60
It is crushed by being sandwiched between the member 11 and the side member 12.
Therefore, load-displacement characteristics as shown in FIG. 13 are exhibited, and a part of impact energy can be effectively absorbed.

The eighth embodiment shown in FIG. 14 is different from the eighth embodiment in that an elastic spacer 61 made of an elastomer is interposed between the vehicle body side mounting end 11a of the FRP member 11 and the side member 12.
The mounting end 11a can be inclined to some extent in the vehicle longitudinal direction. In this case, when the FRP member 11 is bent by the load F, the displacement of the free end 11b in the vehicle width direction is absorbed by the mounting end 11a being inclined to the elastic spacer 61 side to some extent.

The specific mode such as the mounting direction of the FRP member 11 may be other than the above embodiment. For example, both ends 1 of the FRP member 11
The FRP member 11 may be attached in such a direction that at least one of 1a and 11b can be displaced in the vertical direction of the vehicle body.

[Effects of the Invention] According to the present invention, when a large load due to a collision or the like is applied to an FRP member having a small radius of curvature interposed between a vehicle body and a bumper main body, excessive force other than bending stress is applied to the FRP member. It is possible to suppress the occurrence of a large stress and to make the FRP member exhibit a predetermined shock absorbing performance.

[Brief description of the drawings]

FIG. 1 is a perspective view of a part of a bumper device showing a first embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the bumper device shown in FIG. 1, and FIG. 3 is shown in FIG. FIG. 4 is a plan view of a bumper device shown in FIG. 4, FIG. 4 is a perspective view of a part of the bumper device showing a second embodiment of the present invention, FIG. 5 is a longitudinal sectional view of the bumper device shown in FIG. Is a perspective view of a part of a bumper device showing a third embodiment of the present invention, FIG. 7 is a longitudinal sectional view of the bumper device shown in FIG. 6, and FIG. 8 shows a fourth embodiment of the present invention. FIG. 9 is a perspective view of a part of a bumper device, FIG. 9 is a plan view of a part of a bumper device showing a fifth embodiment of the present invention, and FIG. 10 is a part of a bumper device showing a sixth embodiment of the present invention. FIG. 11 is a plan view of a part of a bumper device showing a seventh embodiment of the present invention, and FIG.
FIG. 11 is a plan view showing the state of the bumper device shown in FIG. 11 when absorbing shock, FIG. 13 is a diagram showing the shock absorption characteristics of the bumper device shown in FIG. 11, and FIG. 14 is an eighth embodiment of the present invention. FIG. 15 is a plan view showing a part of a bumper device showing an example, and FIG. 15 is a plan view showing a conventional bumper device. 10 bumper device, 11 FRP member, 12 side member (body side member), 13 bumper body, 30 lateral displacement absorption mechanism, 31 holder, 32 friction member, 40, 45, 50 holder , 60
... Auxiliary shock absorber.

Claims (3)

(57) [Claims] 1. A body which is formed in a substantially U or J curved shape and has one end connected to a member on the vehicle body side and the other end connected to the body of the pamper, so that a load along the front-rear direction of the car body is reduced. A FRP member that bends in a direction in which the radius of curvature is reduced when loaded on the FRP member, and the FRP member is provided on at least one of between the FRP member and the bumper body or between the FRP member and a vehicle body-side member. A lateral displacement absorbing mechanism that allows the FRP member to be displaced in a direction intersecting the front-rear direction of the vehicle body when the FRP member is deflected in the above direction, for a vehicle equipped with an FRP member. Bumper equipment. 2. A holder mounted on a vehicle body-side member or a bumper body and holding an end of the FRP member so as to be movable in a direction intersecting the front-rear direction of the vehicle body. 2. A friction member comprising a rubber-like elastic body interposed between the holder and the FRP member.
A vehicle bumper device provided with the FRP member described in the above. 3. An FRP is provided between the FRP member and a member on the vehicle body side.
2. A vehicle bumper device having an FRP member according to claim 1, further comprising an auxiliary shock absorber that absorbs collision energy by crushing the member when the member is bent by a load along the front-rear direction of the vehicle body.