JP4328175B2 - Fiber reinforced plastic vehicle hood - Google Patents

Description

  The present invention relates to a vehicle hood made of fiber reinforced plastic.

  Conventionally, many metal hoods are used as vehicle hoods. This metal hood is composed of a frame facing the inner side of the vehicle body and a skin positioned on the upper side of the frame, and the frame is formed with a groove-shaped bent bead extending in the vehicle width direction. At the time of a collision, the hood is designed to be able to absorb the impact force at the time of collision by bending so that the hood is lifted upward from the bent bead (see, for example, Patent Document 1 and Patent Document 2).

In recent years, fiber reinforced plastics (hereinafter referred to as “FRP”), particularly carbon fiber reinforced plastics, have come to be used as members constituting the vehicle body in order to reduce vehicle weight. FRP is obtained by laminating fibers, which are generally reinforcing materials, in a mold except for SMC and BMC, and then curing a matrix resin impregnated in the fibers. Roughly classifying the molding method in the resin impregnation process, there are a method of laminating and molding a prepreg in which fibers are pre-impregnated into a fiber, and a method of molding by impregnating a resin after laminating fibers into a die . Since FRP has a higher specific rigidity and specific strength than other materials such as metal, it is possible to obtain a light and high-rigidity product and is used for exterior parts of vehicle bodies. Food is no exception, and FRP hoods that can be exchanged for genuine hoods are available in the aftermarket market.
Japanese Patent Laid-Open No. 10-129529 (paragraphs 0007 to 0012, FIG. 5, etc.) JP-A-11-198859 (paragraph 0013, etc.)

  However, the FRP hood is characterized by high tensile strength and difficulty in plastic deformation. For this reason, even if the metal vehicle body is greatly plastically deformed in the event of a vehicle collision, the FRP hood only elastically deforms, causing a problem of unbalance (or mismatch) in deformation.

In order to solve the above-mentioned problem, a method is considered in which a bent bead having the same degree as that of a metal hood frame is formed on the frame of the FRP hood so as to be a deformation starting point at the time of collision. However, this method has a problem that the tensile strength of the FRP hood is superior, and the skin (outside of the hood) where the bead is not formed is not bent and cannot be bent well.
And because the hood is not bent sufficiently, an excessive load is applied to the hinge that engages the hood with the hood at the rear end of the hood and the striker that engages the hood with the hood at the front end. Another problem is that the parts are damaged.
If the mechanical strength of the FRP hood is reduced by increasing the notch of the folded bead, the FRP hood can be deformed at a desired location in the event of a collision. There is also a risk that the mechanical strength of will not be satisfied.

  Another possible method is to make a cut extending in the vehicle width direction in the reinforcing fiber used in the FRP so that the portion is easily bent. However, in this method, the strength of the cut portion is reduced, and when a hood is manufactured by laminating reinforcing fibers, the fiber frays from the cut and the workability is deteriorated. .

  Accordingly, an object of the present invention is to solve the above-described problems and to provide an FRP vehicle hood that has sufficient strength in a normal use state and is deformed so as to absorb an impact force at the time of a collision.

In order to solve the above-mentioned problem, the invention according to claim 1 is a vehicle hood made of FRP formed by laminating a plurality of layers of reinforcing fibers ; A unidirectional material formed by arranging a plurality of fibers along the vehicle width direction, and the base material has a slit extending in the vehicle width direction, and the unidirectional material includes the slit. the is positioned across characterized Rukoto.

According to the first aspect of the present invention, in the FRP vehicle hood in which a plurality of layers of reinforcing fibers are laminated, at least one layer is a unidirectional material in which the fibers are arranged along the vehicle width direction. The tensile strength and bending strength in the front-rear direction are lowered. Therefore, for example, when the vehicle collides with the front, the front hood to which the present invention is applied is easy to bend in the vehicle front-rear direction starting from the laminated unidirectional material and the slit , and thus the bend is caused by the collision. Can absorb impact force.
Moreover, the FRP vehicle hood of the present invention can ensure sufficient mechanical strength even in a normal use state by laminating a plurality of layers of reinforcing fibers.
Examples of reinforcing fibers include those in which fibers are woven into a cloth shape.

Portions invention according to claim 2, in the FRP hood according to claim 1, the core material is interposed between the reinforcing fibers, the said core material to match the slit and the longitudinal direction of the vehicle Is provided with a thin-walled portion.

According to the second aspect of the invention, in addition to the action of the FRP vehicle hood according to the first aspect, the core material is provided with the thin portion, so that the mechanical strength of the portion is reduced. . Since the thin portion is provided in a portion that matches the unidirectional material and the slit has become hood easier bending starting from the position where the thin portion and the unidirectional material and the slits are overlapped to absorb the impact force due to the collision be able to. Further, sandwiching the core material forms a sandwich structure, increasing the thickness of the vehicle hood and improving the rigidity.
The “core material” is a material constituting the core of the hood. For example, foam material, honeycomb (made of paper, aramid fiber, aluminum alloy, etc.), hollow molded product (formed by blow molding, etc.) ) And the like. If a foam material is used as the core material, the weight of the hood can be reduced.

  The invention according to claim 3 is the FRP vehicle hood according to claim 1 or 2, wherein the one-way material is provided in a lower layer than an uppermost layer constituting an appearance. To do.

  According to the third aspect of the invention, in addition to the action of the FRP vehicle hood according to the first or second aspect, the unidirectional material is provided below the uppermost layer constituting the appearance of the vehicle hood. Therefore, the boundary is not visually observed, and the design of the vehicle hood is not impaired.

  According to the FRP vehicle hood described in claim 1, the unidirectional members are laminated, so that it is easy to be plastically deformed in the vehicle front-rear direction at the time of a collision, and an impact force can be absorbed.

According to the FRP vehicle hood according to claim 2, since the thin portion is provided in the core material, the core portion is more easily deformed at the position where the thin portion overlaps the one-way material and the slit. Power can be absorbed more reliably. Moreover, the sandwich structure can be formed by interposing the core material, and the overall rigidity can be improved.

  According to the vehicle hood described in claim 3, since the unidirectional material is not disposed in the uppermost layer, the boundary is not visually observed, and the design property is not impaired.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is a plan view of a front hood with a skin omitted, and FIG. 2 is an exploded perspective view of the front hood according to the present embodiment.

A front hood 1 shown in FIG. 1 is mounted in front of a vehicle (see FIG. 4A) and covers an engine room and the like.
As shown in FIG. 2, the front hood (vehicle hood) 1 includes a skin 10, a frame 20 positioned on the lower surface side of the skin 10, a core member 30 sandwiched between the skin 10 and the frame 20, The solid laminated portion 40 having a unidirectional material is integrally formed (see FIG. 4A).

The skin 10 constitutes the appearance of the vehicle, and the frame 20 faces the engine room or the like. The skin 10 and the frame 20 shown in FIG. 2 are formed in a substantially trapezoidal shape in plan view from an FRP obtained by impregnating and curing an epoxy resin that is a synthetic resin on a sheet in which carbon fibers that are reinforcing fibers are knitted in a cross shape. (See FIG. 1).
By using the carbon fiber as a reinforcing material knitted in a cross shape (bidirectional) in this way, the skin 10 and the frame 20 can improve the hood rigidity and strength in the vehicle longitudinal direction and the vehicle width direction, Weight reduction can be achieved. In addition to carbon fibers, examples of reinforcing fibers used in FRP include glass fibers, Kevlar fibers, polyethylene fibers, and polyamide fibers. Moreover, as a matrix resin used for FRP, an unsaturated polyester resin, a vinyl ester resin, a phenol resin, etc. other than an epoxy resin are mentioned.

  In addition, when the groove shape D (see FIG. 4) is formed on the lower surface of the frame 20 along the stacking position of the unidirectional material 42 to be described later, the external force from the front of the vehicle is reduced. It becomes easy to undergo plastic deformation starting from the portion.

  The core material 30 shown in FIG. 2 is used to improve the rigidity of the entire hood, and is formed from urethane foam. The core material 30 has substantially the same shape as the skin 10 and the frame 20 in a plan view, but has an opening 31 at the center for weight reduction. Further, groove-shaped thin portions 32 are provided at both ends of the core material 30 in the vehicle width direction. For this reason, when an external force is applied in front of the vehicle, it is easy to bend with the thin portion 32 as a starting point. In addition, as a foaming material used as the core material 30, the foaming material etc. which consist of an acrylic, a polystyrene, and a polyimide other than foaming urethane are mentioned. By using a foam material, the weight of the front hood 1 can be reduced.

As shown in FIGS. 2 and 3, the solid laminated portion 40 is provided with a slit 41 a extending in the vehicle width direction on the base material 41, and a unidirectional material 42 is arranged along the vehicle width direction from above the slit 41 a. Configured.
The base material 41 is made of reinforcing fibers similar to those of the skin 10 and the frame 20 described above, is formed in a shape that matches the opening 31 of the core material 30, and is fitted into the opening 31. The slit 41a is provided in a portion that coincides with the thin portion 32 of the core material 30 in the vehicle front-rear direction. The slit 41a may be formed by completely dividing the base material 41 (gap), or may be formed by partially cutting the base material 41 in the vehicle width direction. Good.

  The unidirectional material 42 is formed by aligning a plurality of reinforcing fibers in one direction, and the reinforcing fibers cannot be unraveled by stitches or the like. The unidirectional material 42 has a high tensile strength in a direction parallel to the reinforcing fiber, and a low tensile strength and bending strength in a direction perpendicular to the reinforcing fiber. In other words, when the reinforcing fiber having a predetermined width is disposed along the vehicle width direction, the unidirectional member 42 is strong against an external force in the vehicle width direction and weak against an external force in the vehicle front-rear direction. In addition, what is used for FRP, such as above-mentioned skin 10, etc. can be applied as a reinforcing fiber and a synthetic resin.

According to the above, in the front hood 1 according to the present embodiment, the following operational effects can be obtained.
Since the front hood 1 has the unidirectional members 42 laminated in the vehicle width direction, the tensile strength and bending strength in the vehicle front-rear direction are low. Therefore, as shown in FIG. 4B, when an impact force F is applied from the front during a vehicle collision, stress concentrates on the unidirectional member 42 and plastic deformation is likely to occur. And the impact force by a collision can be absorbed by bending so that it may raise upwards from the unidirectional material 42 and the slit 41a . Incidentally, the unidirectional member 42 increases the mechanical strength in the vehicle width direction in order to increase the tensile strength in the vehicle width direction.
In addition, since the front hood 1 is formed by the skin 10 and the frame 20, sufficient mechanical strength can be ensured even in a normal use state (a state in which a large external force is not applied).

Furthermore, the thickness of the front hood 1 can be increased and the rigidity can be improved by interposing the core material 30 between the skin 10 and the frame 20 to form a sandwich structure. Since this core material 30 is provided with the thin-walled portion 32, the mechanical strength of that portion is low. Since the thin portion is provided in a portion that matches the unidirectional material and the slit, the position overlapping the thin portion and the unidirectional material and the slit has become front hood 1 is likely more bent starting from the, the impact force due to the collision Can be absorbed.

And since the unidirectional material 42 is arrange | positioned between the skin 10 and the flame | frame 20, the boundary is not visually recognized on the external appearance, and designability is not impaired.
When the front hood 1 is manufactured, the unidirectional members 42 need only be arranged and laminated in the vehicle width direction as a starting point of bending, so that there is no fraying of the reinforcing fibers and the workability is improved. be able to.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment.
Figure 5 is a reference example.
For example, in the present embodiment, the solid laminated portion 40 is configured such that the unidirectional material 42 having a predetermined width is disposed on the base material 41. However, as illustrated in FIG. You may make it laminate | stack. In this way, the alignment work at the time of laminating the unidirectional material 42 becomes unnecessary, and workability is improved. Further, in the core material 50 that does not have the opening 31, the unidirectional material 44 having a predetermined width may be laminated on the frame 20 as shown in FIG. 5B, or as shown in FIG. In addition, the unidirectional material 45 may be laminated on the entire surface of the frame 20. Furthermore, in the configuration shown in FIGS. 5B and 5C, the core material 30 having the opening 31 can be applied instead of the core material 50.

  In the present embodiment, the unidirectional material 42 is provided in the solid laminated portion 40 located in the intermediate layer, but it may be provided on the skin 10 constituting the appearance.

In the present embodiment, the skin 10, the frame 20, and the solid stacked portion 40 are stacked one by one, but a plurality of layers may be stacked. A desired rigidity can be obtained by laminating a plurality of sheets. Further, a plurality of the unidirectional members 42 may be laminated, or the unidirectional members may be laminated with a predetermined width or the entire surface.
In the present embodiment, the core material 30 is interposed between the skin 10 and the frame 20, but the core material 30 may not be interposed.

In this embodiment, first, reinforcing fibers for skin shape formation are laminated on a mold, then a core material is set, and finally reinforcing fibers for frame shape formation are laminated, and then impregnated and cured with a matrix resin. The front hood 1 is manufactured by integral molding. In addition, the front hood 1 may be manufactured by integral molding after the reinforcing fibers are impregnated with the matrix resin at the time of lamination, or after the prepreg impregnated with the matrix resin is laminated.
Further, the front hood 1 can be manufactured by individually molding the skin 10, the frame 20, the solid laminated portion 40, and the like and then bonding them.

  In addition, in this embodiment, although applied to the front hood, it can also be applied to the rear hood. By applying to the rear hood, the impact force can be absorbed by bending the rear hood in the vehicle width direction even in a collision (rear collision) from the rear of the vehicle.

It is a top view of the front hood which abbreviate | omitted skin. It is a disassembled perspective view of the front hood which concerns on embodiment. It is FRP laminated structure sectional drawing of a vehicle front-back direction. It is a figure explaining how a front hood bends. It is an exploded perspective view showing a reference example of a front hood of implementation forms.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front hood 10 Skin 20 Frame 30 Core material 31 Opening part 32 Thin part 40 Solid laminated part 41 Base material 41a Slit 42,43,44,45 Unidirectional material 50 Core material D Groove shape

Claims (5)

In a vehicle hood made of fiber reinforced plastic formed by laminating multiple layers of reinforcing fibers,
A base material in which reinforcing fibers are knitted in a cross shape;
A unidirectional material formed by arranging a plurality of fibers along the vehicle width direction ,
The base material has a slit extending in the vehicle width direction,
The unidirectional material is fiber reinforced plastic hood, it characterized that you have been positioned across the slit. Wherein the core material is interposed between the reinforcing fibers, fiber reinforced plastic according to claim 1 in the core material, wherein a thin portion is provided in a portion matching with the slit and the longitudinal direction of the vehicle Vehicle hood.   3. The fiber reinforced plastic vehicle hood according to claim 1, wherein the unidirectional material is provided in a lower layer than an uppermost layer constituting an appearance. 4. The substrate is formed by dividing into two parts,
4. The fiber-reinforced plastic vehicle hood according to claim 1, wherein the slit is formed with a gap between the two base materials. 5. The core material has an opening in the center,
The fiber reinforced plastic vehicle hood according to claim 2, wherein the base material is formed in a shape that matches the opening, and is fitted into the opening.

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