JP2023147865A - Reinforcing structure of vehicle exterior material - Google Patents

Abstract

To stiffen vehicle exterior material with reinforcement material having various kinds of properties.SOLUTION: Reinforcing structure of vehicle exterior material is provided, comprising: exterior material (door outer panel 8) to be an exterior of a vehicle; and reinforcing material 20 fixed to the exterior material (8). In the reinforcing structure, the reinforcing material 20 is formed by laminating cellulosic fibers and includes: a proximal portion 21 forming an outer shape of the reinforcing material 20; and a plurality of hollow columnar convex portions 22 which rise from the proximal portion 21. A stationary portion 30 fixed to the exterior material (8) is arranged at one of a ceiling portion 220 that is a ceiling of the convex portion 22 and the proximal portion 21, and a rigidity portion 40 restricting deformation of the reinforcing material 20 is arranged at the other of the ceiling portion 220 that is the ceiling of the convex portion 22 and the proximal portion 21.SELECTED DRAWING: Figure 7

Description

The present invention relates to a stiffening structure for a vehicle exterior material, which includes an exterior material forming the exterior of a vehicle, and a reinforcing material fixed to the exterior material.

In the field of vehicles, the exterior material that forms the exterior of the vehicle is sometimes stiffened with a reinforcing material. For example, when the exterior material is partially thinned in order to reduce the weight of the vehicle, a reinforcing material is fixed to the thinned portion. However, when a resin plate is used as a reinforcing material, the thickness of the plate must be increased in order to ensure its rigidity, and this structure is not suitable for suppressing an increase in the weight of the exterior material. Furthermore, when a plate material is heat-sealed to a thinned portion of the exterior material, the exterior material may be distorted due to heat shrinkage of the resin, and it may take time to maintain an excellent appearance.

Here, in the technique disclosed in Patent Document 1, a dense plate material is fixed to the interior material of a vehicle. This dense plate material is composed of a pulp molded body formed by laminating cellulose fibers. Pulp molded articles have both appropriate rigidity and light weight, and are used in various fields. Therefore, it may be possible to stiffen the structure by fixing a dense plate material made of a pulp molded body to the exterior material.

Japanese Patent Application Publication No. 2008-280005

However, reinforcing materials for exterior materials are required to have higher rigidity than reinforcing materials for interior materials. For this reason, when a dense plate made of a pulp molded body is used, it is necessary to increase the thickness of the plate like a resin plate from the viewpoint of ensuring its rigidity, and there is a problem in that it is difficult to suppress an increase in weight. The present invention has been devised in view of the above-mentioned points, and the problem to be solved by the present invention is to stiffen the exterior material of a vehicle with a reinforcing material that has various performances.

As a means for solving the above problems, a stiffening structure for a vehicle exterior material according to a first aspect of the invention includes an exterior material forming the exterior of a vehicle, and a reinforcing material fixed to the exterior material. In this type of stiffening structure, it is desirable to be able to stiffen the exterior material with a reinforcing material that has various properties such as rigidity and lightness. Therefore, the reinforcing material of the present invention is formed by laminating cellulose fibers, and has a base portion forming the outer shape of the reinforcing material, and a plurality of hollow columnar convex portions rising from the base portion. A fixing part that is fixed to the exterior material is provided on one of the ceiling part and the base that forms the ceiling of the convex part, and a fixing part that is fixed to the exterior material is provided on either one of the ceiling part and the base that make up the ceiling of the convex part. On the other hand, a rigid portion is provided to restrict deformation of the reinforcing material. Since the reinforcing material of the present invention is formed by laminating cellulose fibers, it has excellent rigidity and lightness. Further, since the reinforcing material has a hollow convex portion rising from the base, it has a structure that makes it easier to ensure the desired lightness compared to a dense plate material. Then, the fixing part provided on one side of the convex part and the base and the rigid part provided on the other side of the convex part and the base are separated in the direction away from the exterior material, thereby reinforcing the This ensures the rigidity of the material.

A stiffening structure for a vehicle exterior material according to a second aspect of the invention is such that, in the stiffening structure for a vehicle exterior material according to the first invention, the rigid portion is formed continuously without interruption in the surface direction of the plate-shaped exterior material. . In the present invention, since the rigid portion is formed to extend in the plane direction of the exterior material, the tensile strength of the reinforcing material in the plane direction of the exterior material can be more reliably ensured.

A reinforcing structure for a vehicle exterior material according to a third invention is a reinforcement structure for a vehicle exterior material according to the second invention, in which the reinforcing structure portion as a rigid portion forms a ceiling portion of a convex portion different from one of the reinforcement structures. and the base. In the present invention, the tensile strength of the reinforcing material can be more reliably ensured by the reinforcing structure provided at the base or ceiling portion.

In the stiffening structure for a vehicle exterior material of the fourth invention, in the stiffening structure for a vehicle exterior material of the third invention, the reinforcing structure portion has better water resistance than the base portion and the convex portion. In the present invention, the performance of the reinforcing material can be more appropriately ensured by the reinforcing structure having water resistance and rigidity.

A reinforcing structure for a vehicle exterior material according to a fifth invention is a stiffening structure for a vehicle exterior material according to any one of the first to fourth inventions, wherein the fixing part is provided between the convex part and the exterior material. It is an adhesive layer. In the present invention, the exterior material and the reinforcing material can be more firmly fixed by the fixing portion made of the adhesive layer. Furthermore, in the present invention, the rigidity (tensile strength, etc.) of the rigid portion can be set in consideration of the balance with the adhesive strength of the fixed portion to the exterior material.

A stiffening structure for a vehicle exterior material according to a sixth aspect of the invention is such that in the stiffening structure for a vehicle exterior material according to the fifth invention, a hole portion into which an adhesive layer is inserted is provided in a ceiling portion forming a ceiling of the convex portion. It is formed to extend in the direction away from the material. In the present invention, the exterior material and the reinforcing material can be fixed even more firmly by the adhesive layer that has entered the hole of the convex portion.

According to the first aspect of the present invention, it is possible to stiffen the exterior material of a vehicle using a reinforcing material that has various performances. Moreover, according to the second invention, the rigidity of the reinforcing material can be ensured more reliably. Moreover, according to the third invention, the rigidity of the reinforcing material can be ensured even more reliably. Moreover, according to the fourth invention, the water resistance and rigidity of the reinforcing material can be ensured more reliably. Moreover, according to the fifth invention, the attachability and rigidity of the reinforcing member can be more appropriately ensured. According to the sixth aspect of the invention, it is possible to ensure the attachment of the reinforcing material even more reliably.

FIG. 2 is a perspective view of the vehicle. FIG. 2 is a perspective front view of the door outer panel showing a thin section. It is a schematic perspective view of a thin part and a reinforcement material. FIG. 3 is a schematic perspective view of a portion of the reinforcing material showing a convex portion. FIG. 3 is a schematic enlarged perspective view of a reinforcing material showing an enlarged convex portion. FIG. 3 is a schematic cross-sectional view of a thin wall portion and a reinforcing material. FIG. 3 is a schematic cross-sectional view of a thin walled portion and a reinforcing member under load. FIG. 7 is a schematic cross-sectional view of a reinforcing material of Modification 1. 7 is a schematic cross-sectional view of a portion of a reinforcing material of Modification Example 2. FIG. FIG. 7 is a schematic vertical cross-sectional view of a portion of a reinforcing material of Modification 3. It is a graph showing the results of a stiffness measurement test of an example and a comparative example.

Embodiments for carrying out the present invention will be described below with reference to FIGS. 1 to 11. For convenience, arrows indicating the longitudinal direction, vertical direction, and horizontal direction of the vehicle and the reinforcing material are appropriately shown in each figure based on the state in which the reinforcing material is disposed on the exterior material of the vehicle.

[Vehicle structure]
Before explaining the stiffening structure of the vehicle exterior material, first, the outline of the vehicle shown in FIG. 1 will be explained. In this vehicle 2, a front door opening 3 corresponding to a front seat and a rear door opening 4 corresponding to a rear seat are formed on a side surface of the vehicle body. Further, a roof panel 5 constituting a ceiling portion of the vehicle 2 is disposed on the upper side of the vehicle interior R in which the front seats and rear seats are installed. The front door opening 3 is configured to be openable and closable by a front door 6 that is rotatable around a door hinge (not shown). Further, the rear door opening 4 is configured to be openable and closable by a rear door 7 (described in detail later) that slides in the longitudinal direction of the vehicle.

Here, the rear door 7 shown in FIG. 1 is formed into a hollow closed cross-sectional shape by joining a metal plate-shaped door outer panel 8 and door inner panel 9 at their peripheral edges. Moreover, a plurality of pipe-shaped reinforcements (not shown) are arranged between the door outer panel 8 and the door inner panel 9 so as to extend in the vehicle longitudinal direction. The door outer panel 8 is a member corresponding to the exterior material of the present invention, and constitutes the exterior portion of the rear door 7. As shown in FIG. 2, this door outer panel 8 is formed into a generally rectangular shape when viewed from the front, and the vehicle longitudinal direction and vehicle vertical direction correspond to the surface direction of the door outer panel 8.

[Reinforcing structure of vehicle exterior material]
In the vehicle exterior material stiffening structure, the door outer panel 8 (exterior material) described above is stiffened with a reinforcing material 20 shown in FIGS. 2 and 3. That is, the door outer panel 8 is comprised of a door main body part 80 formed in a generally rectangular shape when viewed from the front as shown in FIG. 2, and a window frame part 81 provided at the upper part of the vehicle of the door main body part 80. A thin wall portion 10 is formed in the door body portion 80 from the viewpoint of weight reduction. The thin portion 10 is formed to extend in the longitudinal direction of the vehicle with a predetermined width dimension in the vehicle vertical direction, and has a smaller thickness dimension (horizontal dimension) than the other portions of the door outer panel 8. The thin wall portion 10 of the door outer panel 8 is stiffened by fixing the reinforcing material 20 as shown in FIG. It is desirable that this is ensured. Therefore, in this embodiment, the door outer panel 8 is stiffened using a reinforcing material 20 that has various performances described below. Hereinafter, details of the reinforcing material 20 for the door outer panel 8 will be explained.

[Reinforcement material]
The reinforcing member 20 shown in FIG. 3 is formed in a rectangular shape that is elongated in the longitudinal direction of the vehicle, and is adapted to be fitted into the thin wall portion 10. The reinforcing material 20 is provided with a base 21 forming the outer shape of the reinforcing material 20, and a plurality of convex portions 22 rising from the base 21 (in FIG. 22, and the other convex portions are given the common code (22)). As shown in FIG. 4, the reinforcing material 20 is formed with a plurality of rows C1 to C5 in which the convex portions 22 are arranged at predetermined intervals (equal intervals in FIG. 4) in the longitudinal direction of the vehicle. The plurality of rows C1 to C5 of the convex portions 22 are arranged in parallel at predetermined intervals (equal intervals in FIG. 4) in the vertical direction of the vehicle.

Here, since the convex portions 22 (22) shown in FIGS. 3 and 4 have roughly the same basic configuration, the details will be explained using one convex portion 22 as an example. As shown in FIG. 5, the convex portion 22 is a hollow columnar portion having an approximately truncated quadrangular pyramid shape, and protrudes from the base portion 21 in the thickness direction of the door outer panel 8 (in the left-right direction in each figure). A ceiling portion 220 that forms the ceiling of the convex portion 22 is formed into a rectangular plate shape in plan view, and is generally flat so that it can come into surface contact with the thin portion 10 described above. Note that in the convex portion 22, the base portion 21 is not disposed on the bottom side (the right side in each figure) of the ceiling portion 220, so that the convex portion 22 is in an open shape. Further, the convex portion 22 is formed into a hat shape when viewed in longitudinal section from the viewpoint of ensuring rigidity. That is, the paired circumferential parts of the convex portion 22 (the rear side part 221 and the front side part 222, the upper side part 223 and the lower side part 224) are inclined to gradually move away from each other as they move toward the base 21.

The reinforcing member 20 shown in FIGS. 3 and 4 has a base 21 formed to form the outer shape of the reinforcing member 20, and this base 21 is formed between adjacent convex portions 22. That is, the base portion 21 is formed to extend linearly in the longitudinal direction of the vehicle between rows (for example, C1 and C2) of convex portions 22 adjacent to each other in the vertical direction of the vehicle. Further, the base portion 21 is also formed between adjacent convex portions 22 (22) in the vehicle longitudinal direction so as to extend linearly in the vehicle vertical direction. In this way, the base portion 21 of the reinforcing member 20 is formed in a lattice shape in the vehicle longitudinal direction and the vehicle vertical direction, so that it continues seamlessly in the surface direction of the door outer panel 8 (exterior material).

[Material of reinforcing material]
Here, the reinforcing material 20 shown in FIGS. 3 to 5 is made of a material in which a plurality of cellulose fibers are integrated in a laminated state from the viewpoint of ensuring rigidity and lightness. Various types of cellulose fibers can be used as this type of cellulose fiber, such as plant fibers (natural fibers), regenerated fibers, refined fibers, and semi-synthetic fibers. Cellulose fibers can be suitably used. By using cellulose fibers obtained from pulp as the material for the reinforcing material 20, it is possible to contribute to the reduction of _CO2 emissions and environmental load in accordance with life cycle assessment (LCA). Furthermore, the surface of the reinforcing material 20 has appropriate rigidity and hardness due to the dense intertwining and integration of cellulose fibers, making it possible to appropriately insulate and absorb sound from inside and outside the vehicle. It becomes.

[Formation method of reinforcing material]
Further, the method of forming the reinforcing material 20 shown in FIGS. 3 to 5 can be set as appropriate depending on the material to be used. For example, in this embodiment, the reinforcing material 20 is formed of a material in which cellulose fibers are integrated in a laminated state by pulp molding using a mold (not shown). This mold has an outer shape that follows the outer shape of the reinforcing material 20, and a liquid suction port is formed at the appropriate location. In pulp molding, a mold covered with a net material is immersed in a liquid stock solution containing cellulose fibers (details will be described later). In this state, cellulose fibers can be laminated on the net material by sucking the undiluted liquid from the liquid suction part. After a desired amount of cellulose fibers are laminated on the net material, the mold is lifted from the raw solution, and the laminated cellulose fibers are dried and integrated.

Here, the method for forming the stock solution for pulp molding is not particularly limited, but as a general method, a predetermined amount (for example, an amount with a solid content of 0.5% by weight or more) of pulp is poured into water, and then An example of this method is to stir the mixture until it becomes a slurry. As the pulp, chemical pulp, mechanical pulp, waste paper pulp, and non-wood pulp can be used singly or in combination of two or more kinds, and it is particularly desirable to use waste paper pulp from the viewpoint of recyclability. Examples of this type of waste paper pulp include disintegrated waste paper pulp, defibrated/deinked waste paper pulp, and defibrated/deinked/bleached waste paper pulp.The raw materials for this waste paper pulp include wood-free paper, medium-quality paper, low-grade paper, newspaper, and leaflets. It can be obtained from sorted or unsorted waste paper such as magazines. Chemical pulps include softwood unbleached kraft pulp (NUKP), hardwood unbleached kraft pulp (LUKP), softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP), softwood semi-bleached kraft pulp (NSBKP), and hardwood semi-bleached kraft pulp (NSBKP). Examples include bleached kraft pulp (LSBKP), softwood sulfite pulp, and hardwood sulfite pulp. Examples of mechanical pulp include stone ground pulp (SGP), pressurized stone ground pulp (PGW), refiner ground pulp (RGP), thermoground pulp (TGP), chemical ground pulp (CGP), and thermomechanical pulp (TMP). can. Examples of non-wood pulp include pulps made from non-wood fibers such as kenaf, hemp, and reed.

Additives that contribute to improving the performance of the reinforcing material 20 shown in FIGS. 3 to 5 can be added to the stock solution. These types of additives include sizing agents, paper strength enhancers such as dry paper strength agents and wet paper strength agents, PH adjusters, freeness improvers, antifoaming agents, bulking agents, retention agents, antibacterial agents, Examples include antifungal agents, fillers, and dyes. Among these, sizing agents that prevent water from penetrating and contribute to improved water resistance, dry paper strength agents that contribute to improving breaking strength (strength) in dry conditions, and wet paper strength agents that contribute to improved strength when wet. Preferably, at least one of the agents is added to the stock solution. Examples of sizing agents include rosin-based sizing agents, AKD-based sizing agents, alkenyl succinic anhydride (ASA)-based sizing agents, petroleum-based sizing agents, and neutral rosin sizing agents. Examples of dry paper strength agents include polyacrylamide polymers such as anionic polyacrylamide resins, polyvinyl alcohol polymers, cationic starches, various modified starches, urea/formalin resins, and melamine/formalin resins. Further, as a wet paper strength agent, a polyamide polyamine epichlorohydrin resin (or a modified product thereof) can be exemplified. Note that the amount of each additive added to the stock solution is not particularly limited as long as desired performance can be imparted to the reinforcing material 20. For example, the sizing agent can be added in an amount of 0.5% to 5% by weight, and preferably 1.0% by weight or more. The dry paper strength agent can be added in an amount of 0.5% to 5% by weight, and preferably 3.0% by weight or more. Further, the wet paper strength agent can be added in a range of 2% by weight to 15% by weight, and preferably 4.0% by weight or more.

[Characteristics of reinforcing material]
The reinforcing material 20 after molding shown in FIGS. 3 to 5 has appropriate rigidity as described above, and the rigidity can be defined by Young's modulus. Here, Young's modulus can be measured by a tensile test based on "JIS K 7113". The reinforcing material 20 made of a pulp molded body typically has a tightness (apparent specific gravity) corresponding to density in the range of 300 kg/m ³ to 400 kg/m ³ and a Young's modulus of 0.2 GPa to 0.2 GPa. It has an excellent stiffness in the range of 8 GPa. Further, by subjecting the base 21 to compression treatment, the tensile strength of the base 21 can be improved. For example, by pressing the base 21, the tension of the base 21 can be made larger than 400 kg/m ³ , for example, from 450 kg/m ³ to 800 kg/m ³ . The tensile strength of the base portion 21 is 1 MPa to 6 MPa before pressing, and 2 MPa to 15 MPa after pressing.

Moreover, since the reinforcing material 20 after molding is composed of a laminate of cellulose fibers, it is lighter than the metal door outer panel 8. The average thickness dimension of the reinforcing material 20 (average stacked amount of cellulose fibers after drying) is not particularly limited as long as it can ensure appropriate rigidity of the reinforcing material 20, but it is necessary to make it larger than necessary from the viewpoint of ensuring lightness. There isn't. For example, the average thickness of the reinforcing material 20 can typically be set in the range of 0.2 mm to 15 mm from the viewpoint of ensuring its rigidity, and may be set within the range of 1.0 mm to 8.0 mm from the viewpoint of ensuring desired lightness and rigidity. It can also be set to a range. When the reinforcing material 20 has an appropriate thickness, the layer of cellulose fibers acts as a buffer layer against vibrations and heat, and has predetermined vibration damping and heat insulation properties.

[Reinforcing material placement method (formation of fixed part and rigid part)]
Next, a method of fixing the reinforcing material 20 to the thin wall portion 10 of the door outer panel 8 will be described with reference to FIGS. 5 and 6. First, the convex portion 22 (22) of the reinforcing member 20 is arranged so as to face the thin wall portion 10, and the ceiling portion 220 of this convex portion 22 is fixed to the thin wall portion 10. At this time, the method of fixing the reinforcing material 20 is not particularly limited, but by using a liquid adhesive or a sheet adhesive, a predetermined adhesive strength (details will be described later) can be provided between the ceiling portion 220 and the thin wall portion 10. An adhesive layer 15 can be formed. In this embodiment, the adhesive layer 15 between the ceiling portion 220 and the thin wall portion 10 corresponds to the fixing portion 30 fixed to the door outer panel 8 (exterior material). Examples of the adhesive component of the adhesive and the adhesive include a heat-curable adhesive component, a non-heat-curable adhesive component, and an adhesive component with vibration damping properties.

Further, in the reinforcing member 20 fixed to the thin wall portion 10 shown in FIG. 6, the base portion 21 thereof is spaced away from the door outer panel 8 (in the left-right direction in FIG. 6). Therefore, by forming the base 21 continuously in the longitudinal direction of the vehicle as described above, the tensile strength (details will be described later) of the reinforcing material 20 provided with the base 21 in the longitudinal direction of the vehicle etc. is ensured. It becomes like this. That is, in this embodiment, the base 21 of the reinforcing material 20 itself corresponds to the rigid portion 40 that restricts the deformation of the reinforcing material 20. Furthermore, in the reinforcing material 20, the base portion 21 as the rigid portion 40 is formed in a lattice shape and is continuous in the longitudinal direction of the vehicle and the vertical direction of the vehicle, so that the tensile strength of the reinforcing material 20 is further ensured. Become. In the above-described configuration, the fixed part 30 and the rigid part 40 are arranged apart from each other, so that the reinforcing material 20 forms a sandwich structure with excellent rigidity, and the thin part 10 of the door outer panel 8 can be properly fixed. It becomes possible to stiffen.

[Relationship between fixed part and rigid part]
Next, the adhesive strength in the shear direction (direction perpendicular to the left-right direction in FIG. 6) of the adhesive layer 15 as the fixing part 30 shown in FIG. 6 and the tensile strength of the base part 21 as the rigid part 40 will be described. The adhesive strength in the shear direction of the adhesive layer 15 and the tensile strength of the base 21 are not particularly limited as long as the performance required for the reinforcing material 20 can be ensured, but it is important to balance them so that either one does not become extremely strong. desirable. That is, if the adhesive strength of the adhesive layer 15 in the shear direction is extremely strong, stress will be concentrated on the base 21 when a load is applied to the door outer panel 8, making it easy to buckle or break. Furthermore, if the tensile strength of the base portion 21 is extremely high, stress will be concentrated on the adhesive layer 15 when a load is applied to the door outer panel 8, making it easy to peel off. Therefore, the adhesive strength of the adhesive layer 15 in the shear direction is set in the range of 10 N/cm ² to 100 N/cm ² , more preferably in the range of 40 N/cm ² to 80 N/cm ² . Further, the tensile strength of the base portion 21 is set in the range of 1 MPa to 15 MPa, more preferably in the range of 2 MPa to 8 MPa. In this way, by setting the adhesive strength of the adhesive layer 15 in the shear direction and the tensile strength of the base 21 within the above ranges, it is possible to balance both strengths. Note that the adhesive strength of the adhesive layer 15 in the shear direction can be measured in accordance with "JIS K 6850:1999".

Further, with reference to FIGS. 4 to 6, the total area of the ceiling portion 220 of the convex portion 22 (22) and the total area of the base portion 21 are not particularly limited as long as the performance required of the reinforcing material 20 can be ensured. It is desirable to set it in consideration of the balance between the adhesive strength and tensile strength described above. For example, when the total area of the ceiling part 220 is 1, the area of the base 21 is set in the range of 0.3 to 3, more preferably in the range of 0.6 to 2.0, thereby achieving the above adhesive strength and tensile strength. Easier to balance strength. If the area ratio of the base 21 to the ceiling portion 220 is less than 0.3, the thickness of the base 21 must be increased from the viewpoint of ensuring tensile strength, and it may take time to suppress an increase in weight. Furthermore, if the area ratio of the base 21 to the ceiling portion 220 exceeds 3, it may take time to select an adhesive or the like from the viewpoint of securing adhesive strength, and there is a risk that costs may increase.

[Function of reinforcing material]
In the above-described stiffening structure for vehicle exterior materials, stiffening is achieved by fixing a reinforcing material 20 to the thin wall portion 10 of the door outer panel 8, as shown in FIGS. 3 to 6. Since the reinforcing member 20 has a plurality of hollow convex portions 22 (22) formed on the base 21, it has appropriate rigidity and is lighter than the door outer panel 8. Since the reinforcing material 20 has a sandwich structure with excellent rigidity as described above, it is possible to appropriately stiffen the thin wall portion 10 of the door outer panel 8. Therefore, as shown in FIG. 7, when a load F is applied to the door outer panel 8 from the outside in the vehicle width direction, the reinforcing material 20 can suppress the bending deformation of the thin wall portion 10 of the door outer panel 8 as much as possible. In addition, since the reinforcing material 20 is made of cellulose fiber, it has excellent properties such as rigidity and lightness (sound absorption, sound insulation, vibration damping, heat insulation, etc.), and can be made from pulp, etc. It is a member with low environmental impact (low LCA). Therefore, in the stiffening structure of the vehicle exterior material, by fixing the reinforcing material 20 that ensures various performances more appropriately to the thin wall portion 10, the door outer panel 8 provided with the thin wall portion 10 can be more appropriately stiffened. It becomes like this.

As explained above, since the reinforcing material 20 of this embodiment is formed by laminating cellulose fibers, it has excellent rigidity and lightness. Further, since the reinforcing material 20 has a hollow convex portion 22 rising from the base 21, the reinforcing material 20 has a structure that makes it easier to ensure the desired lightness compared to a dense plate material. By separating the fixed part 30 provided on one convex part 22 side and the rigid part 40 provided on the other base 21 side in the direction away from the door outer panel 8 (exterior material), the reinforcing material 20 rigidity can be ensured. Therefore, according to this embodiment, the door outer panel 8 of the vehicle 2 can be stiffened using the reinforcing material 20 that has various performances.

Furthermore, in this embodiment, since the rigid portion 40 is formed to extend in the surface direction of the door outer panel 8, the tensile strength of the reinforcing material 20 in the surface direction of the door outer panel 8 can be ensured more reliably. In this embodiment, the door outer panel 8 and the reinforcing material 20 can be more firmly fixed by the fixing portion 30 made of the adhesive layer 15. Furthermore, in this embodiment, the rigidity (tensile strength, etc.) of the rigid part 40 can be set in consideration of the balance with the adhesive strength of the fixing part 30 to the door outer panel 8.

[Modification 1]
Here, the configuration of the reinforcing material may take various configurations in addition to the configuration described above. For example, a reinforcing member 20A of modification example 1 shown in FIG. 8 differs from the embodiment in that a reinforcing structure part 41 as a rigid part 40 is provided on the base 21 side. The reinforcing structure portion 41 serving as the rigid portion 40 is provided continuously in the vehicle longitudinal direction (and vehicle vertical direction) on the base portion 21 side without interruption, and extends in the surface direction of the door outer panel 8 . The reinforcing structure portion 41 is constructed by integrating film materials, plate materials, net materials, pillar materials (including wire materials), etc. as separate members, which will be described later, to the outer surface of the base 21 (the right side in FIG. 8). Can be formed. Further, the reinforcing structure portion 41 can also be formed of a resin layer formed by applying liquid resin to the outer surface of the base portion 21 and then solidifying it.

Here, as the reinforcing structure part 41 as a separate member shown in FIG. 8, materials such as a fiber laminate, a resin or metal member, and a thick paper material can be exemplified. It is desirable that there be. In addition to the fibers exemplified in the reinforcing material 20A, the fiber laminate can be made of high-strength fibers such as carbon fibers such as carbon nanofibers, glass fibers, ceramic fibers, metal fibers, boron fibers, and activated carbon fibers. . The reinforcing structure part 41 can be integrated with the base part 21 by a method such as adhesion or fusion, or can be embedded in the base part 21 during the above-described pulp molding. It is also desirable that the reinforcing structure portion 41 as a resin layer has a rigidity equal to or greater than that of the base portion 21. Examples of this type of resin include polyolefin resins such as polypropylene and polyethylene, ABS (acrylonitrile-butadiene-styrene) resins, acrylic resins, polyester resins, polyurethane resins, polystyrene resins, polyamide resins, polyvinyl chloride resins, fluororesins, polycarbonate resins, etc. Examples include thermosetting resins such as thermoplastic resins, urethane resins, silicone resins, epoxy resins, phenol resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, and thermosetting polyimide resins.

Further, it is desirable that the reinforcing structure portion 41 shown in FIG. 8 has better water resistance (water repellency) than the base portion 21. In addition to the case where the reinforcing structure part 41 itself has water resistance, the water resistance can also be improved by applying water resistance treatment to the reinforcing structure part 41. For example, the surface of the reinforcing structure part 41 can be coated with a coating layer having excellent water resistance. can be formed. Examples of materials for the reinforcing structure portion 41 or the covering layer having this type of water resistance include polyolefin resin, polyamide resin, vinyl chloride resin, fluororesin, acrylic resin, and silicone resin.

According to the reinforcing material 20A of Modification Example 1 shown in FIG. 8, the stiffness (tensile strength of the base 21) of the reinforcing material 20A can be ensured more reliably by the reinforcing structure part 41 as the rigid part 40. Further, the reinforcing structure portion 41 having water resistance and rigidity allows the performance of the reinforcing material 20A to be more appropriately ensured. In the above configuration, the rigidity of the reinforcing member 20A can be ensured by the reinforcing structure part 41 as the rigid part 40, so that it is possible to increase the degree of freedom in selecting the shape of the base part 21. For example, the base portion 21 may meander in the vehicle longitudinal direction (or the vehicle vertical direction), or the base portion 21 may be formed intermittently in the vehicle longitudinal direction. Further, the bottom side of the convex portion 22 may be covered with the reinforcing structure portion 41, and a through hole (not shown) may be provided at an appropriate position of the convex portion 22. By thus communicating the inside and outside of the convex portion 22 (closed space) through the through hole, sound absorption using the Helmholtz resonance principle becomes possible, and the sound absorption properties of the reinforcing material 20A can be more reliably ensured.

[Modification 2]
Further, the configuration of the convex portion can also be changed as appropriate. For example, in the reinforcing material 20B of Modified Example 2 shown in FIG. ) is different from the embodiment. That is, a hole 22H serving as a through hole is formed in the ceiling portion 220 of the convex portion 22B so as to extend in the left-right direction, and the adhesive layer 15 is inserted into the hole 22H and fixed thereto. According to the above configuration, the adhesive layer 15 that has entered the hole 22H of the convex portion 22B functions as an anchor that restricts the movement of the reinforcing material 20B with respect to the door outer panel 8 in the shear direction. Thereby, the door outer panel 8 and the reinforcing material 20B can be fixed even more firmly by the adhesive layer 15 that has entered the hole 22H of the convex portion 22B. Note that the hole portion 22H does not necessarily need to penetrate the ceiling portion 220, and may be a non-through hole or a groove-shaped hole provided in the ceiling portion 220. Further, when a plurality of convex portions are provided on the base, a plurality of holes or a single hole can be provided in all or part of the convex portions.

[Modification 3]
Moreover, the shape of the base can also be changed as appropriate. For example, the reinforcing material 20C of Modified Example 3 shown in FIG. (The depth direction corresponds to the vehicle longitudinal direction). In this modification, the rigidity (tensile strength) of the reinforcing material 20C can be more appropriately ensured by the base 21C formed in a convex curved shape with excellent rigidity.

[Test example]
The present embodiment will be described below based on test examples, but the present invention is not limited to the test examples. [Table 1] below shows the stiffness (test force and displacement slope in the test force range of 10 N to 20 N) of each Example and each Comparative Example.

[Example]
In Example 1, the reinforcing material was manufactured by pulp molding. In addition, in pulp molding, a slurry-like stock solution was used in which a predetermined amount of waste paper pulp was added to water. As shown in FIG. 4, the reinforcing material had a plurality of convex portions formed at approximately equal intervals relative to the base. Further, the average thickness of the reinforcing material was set to 2.0 mm, and the weight was set to 26 g. Further, the internal volume of each convex portion was 9.68 cm ³ . In addition, the total area of the ceiling part of the convex part was set to 67.5 ^cm2 , and the total area of the base part was set to 90 ^cm2 (when the total area of the ceiling part is 1, the area of the base part is set to 1.33 ). Then, the ceiling portion of the convex portion was adhesively fixed to an iron plate (width 150 mm, length 200 mm, thickness 0.4 mm, 118 g) corresponding to the exterior material to create a test piece of Example 1. At this time, the adhesive strength of the adhesive layer was set to 60 N/cm ² and the tensile strength of the base was set to 6.0 MPa.

Further, in Example 2, a reinforcing material was manufactured using the same procedure as in Example 1. In Example 2, a test piece of Example 2 was created by turning the exterior material upside down and adhesively fixing the base to the above-mentioned iron plate.

[Comparative example]
As a test material for Comparative Example 1, a test piece of an iron plate (width 150 mm, length 200 mm, thickness 0.7 mm, 202 g) was prepared. Further, as a test material for Comparative Example 2, a test piece of an iron plate (width 150 mm, length 200 mm, thickness 0.4 mm, 118 g) was prepared. As a test material for Comparative Example 3, an iron plate (width 150 mm, length 200 mm, thickness 0.4 mm, 118 g) in which a dense plate-shaped pulp molded body was adhesively fixed was prepared. In Comparative Example 3, the pulp molded product had an average thickness of 3.0 mm and a weight of 45 g.

[Stiffness measurement test]
The rigidity of the test materials of each Example and each Comparative Example was measured using a compression tester (manufactured by Shimadzu Corporation, trade name: AUTOGRAPH AG-X). The test method was based on the three-point bending test method of "JIS K7171 ISO178", the distance between the supports was 150 mm, and the test speed was 10 mm/min. Then, a load was applied from the side of the iron plate corresponding to the exterior material, and the amount of displacement of each test piece with respect to the test force (load) was measured.

[Results and discussion]
Referring to FIG. 11 and [Table 1], the test piece of Comparative Example 2 has lower rigidity (inclination of test force and displacement) than the test piece of Comparative Example 1, and in the test force range of 10N to 20N, the stiffness is lower than that of the test piece of Comparative Example 1. It decreased to 1/5. Furthermore, although the test piece of Comparative Example 3 had higher rigidity than the test piece of Comparative Example 2, it was found that it was necessary to increase the plate thickness in order to further improve the rigidity.

On the other hand, referring to FIG. 11 and [Table 1], it was found that the test pieces of Example 1 and Example 2 had higher rigidity than the test piece of Comparative Example 2. In particular, it was found that the test piece of Example 1 had higher rigidity than the test piece of Comparative Example 1, and had excellent rigidity. Furthermore, the test piece of Example 2 had higher rigidity than the test piece of Comparative Example 3 in the test force range of 10N to 20N. Here, the test force in the range of 10N to 20N corresponds to external force (water pressure or force applied from a car wash brush) applied to the exterior material during car washing. Therefore, it was found that the test piece of Example 2 was superior in rigidity to the test piece of Comparative Example 3 within the range of external force applied to the exterior material under normal conditions. The above results are considered to be due to the fact that the fixed part and the rigid part were separated from each other to form a sandwich structure in the reinforcing material. In addition, the test pieces of Examples 1 and 2 have a hollow convex portion rising from the base, so they have the desired lightness compared to the test piece of Comparative Example 3 (dense plate material). The configuration was easy to secure. From the weight difference between the test pieces of Examples 1 and 2 and the test pieces of Comparative Examples 1 to 3, it was found that the configurations of Examples 1 and 2 ensured rigidity while suppressing the weight increase. From the above test results, it was found that the reinforcing materials of Examples 1 and 2, which have various performances, can stiffen the exterior material of a vehicle.

Further, in Examples 1 and 2, no buckling deformation of the base or peeling of the adhesive layer occurred in the test force range of 10N to 20N. From this, it was found that in Examples 1 and 2, the adhesive strength of the adhesive layer in the shear direction and the tensile strength of the base were well balanced. When the total area of the ceiling portion is 1, it was easily inferred that by setting the area of the base in the range of 0.3 to 3, it would be easier to balance the adhesive strength and tensile strength described above.

The reinforcing structure of the vehicle exterior material of this embodiment is not limited to the embodiment described above, and may take various other embodiments. In this embodiment, although the structure of the reinforcing material is illustrated, it is not intended to limit the structure of the reinforcing material. For example, the rigid portion can be provided on either the base or the convex portion. That is, a rigid portion can be provided on the ceiling side of the convex portion, and a fixing portion can be provided at the base. In this case, the ceiling part of the convex part itself may be a rigid part, or a reinforcing structure part as a rigid part may be provided in the ceiling part. Further, it is desirable that the base portion is continuous in at least one direction of the surface of the exterior material, and for example, in the form shown in FIG. 3, it is desirable that the base portion be continuous in at least one of the vehicle longitudinal direction and the vehicle vertical direction. In addition to being formed linearly, the base may be formed to be inclined in the longitudinal direction of the vehicle and in the vertical direction. Further, when the base is flat, a rib extending in the longitudinal direction of the vehicle or the like can be provided on the base. Further, a coating layer that contributes only to water resistance may be provided on the rigid portion (either the base portion or the convex portion).

Further, when forming a plurality of convex portions, the shape of each convex portion can be set independently. The shapes of this type of convex portion include shapes such as a truncated quadrangular pyramid, rectangular parallelepiped, and cube, shapes such as a cylinder, truncated cone, and hollow cylinder, and various hollow columnar shapes such as a hemisphere. can. Further, the convex portion can be formed to extend in the surface direction of the exterior material. For example, all the convex portions in a row extending in the longitudinal direction of the vehicle shown in FIG. 3 may be connected to form one convex portion extending in the longitudinal direction of the vehicle.

Further, in this embodiment, although the configuration of the exterior material is illustrated, this is not intended to limit the configuration of the exterior material. For example, the exterior materials can include various parts that make up the exterior of the vehicle, including rear doors, front doors, roof panels, exterior panels such as pillars that support the roof panels, and exterior panels that make up the exterior of the vehicle. Examples include various exterior materials for (QTR panels, etc.). Furthermore, the exterior material does not necessarily have to be plate-shaped. Further, the exterior material can be stiffened at appropriate locations with reinforcing materials, and the locations to be stiffened do not necessarily have to be thin-walled portions. The configurations of the embodiment and each modification can be combined as appropriate.

2 Vehicle R Compartment 3 Front door opening 4 Rear door opening 5 Roof panel 6 Front door 7 Rear door 8 Door outer panel (exterior material of the present invention)
80 Door main body part 81 Window frame part 9 Door inner panel 10 Thin part 15 Adhesive layer 20 Reinforcement material 21 Base part 22 Convex part 30 Fixing part 40 Rigid part 220 Ceiling part 221 Back part 222 Front part 223 Upper part 224 Bottom Side part 20A (Modification 1) Reinforcement 41 Reinforcement structure 20B (Modification 2) Reinforcement 22H Hole 20C (Modification 3) Reinforcement 21C (Modification 3) Base

Claims (6)

A stiffening structure for a vehicle exterior material comprising an exterior material forming the exterior of a vehicle and a reinforcing material fixed to the exterior material,
The reinforcing material is formed by laminating cellulose fibers, and has a base forming the outer shape of the reinforcing material, and a plurality of hollow columnar convex parts rising from the base,
A fixing portion fixed to the exterior material is provided on either one of the ceiling portion forming the ceiling of the convex portion and the base, and a ceiling portion forming the ceiling of the convex portion different from the one. and a rigid portion for regulating deformation of the reinforcing member on the other of the base portions. The stiffening structure for a vehicle exterior material according to claim 1, wherein the rigid portion is formed continuously in a surface direction of the plate-shaped exterior material. 3. The reinforcing structure for a vehicle exterior material according to claim 2, wherein the reinforcing structure as the rigid portion is provided on the other of the base and a ceiling portion forming the ceiling of the convex portion that is different from the one. structure. 4. The reinforcing structure for a vehicle exterior material according to claim 3, wherein the reinforcing structure has better water resistance than the base and the convex portion. The stiffening structure for a vehicle exterior material according to any one of claims 1 to 4, wherein the fixing portion is an adhesive layer provided between the convex portion and the exterior material. 6. The reinforcement of a vehicle exterior material according to claim 5, wherein a hole portion into which the adhesive layer is inserted is formed in a ceiling portion forming a ceiling of the convex portion so as to extend in a direction away from the exterior material. structure.

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