JPS6027059Y2 - car bumper - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an improvement of an automobile bumper.

BACKGROUND ART Conventionally, bumpers installed at the front and rear of an automobile are generally made of metal plates with an open rear part.

Recently, there has been a strong demand for lighter automobiles, and in order to meet this demand, consideration has been given to making bumpers made of plastic.

However, such plastic bumpers tend to warp easily and cannot retain their shape, so it is necessary to reinforce them by attaching a metal plate to the back, and this metal plate is used in conjunction with the bumper. Therefore, it is not possible to reduce the weight significantly, and there is also a risk that the metal plate may inhibit shock absorption in the event of a collision.

In addition, in order to enhance the effect of mitigating the impact in the event of a car collision, it has been proposed that a part of the material is made of elastic urethane rubber, but in this case, a metal plate is also used in order to maintain its shape. , it cannot promote weight reduction.

Therefore, as an improvement to plastic bumpers, it was considered to increase the shape retention by filling the inside of the non-foamed synthetic resin foam that serves as the skin with a plastic foam. If the bumper is made of ordinary hard or semi-hard synthetic resin, it is relatively easy to break and may break even in a slight collision, and if it breaks, it cannot be used and the bumper must be replaced.

Furthermore, the harder the molded body is, the worse the cushioning properties of the molded body itself will be.

In view of the above, the present invention was devised to provide a bumper that is lightweight, has good shape retention, is difficult to break in a minor collision, and has an excellent impact absorption effect. It is characterized in that a skin body made of an elastic material such as an elastic synthetic resin or rubber is wrapped around the outside of a foamed body formed by foaming resin particles copolymerized with a polyurethane resin.

Next, embodiments of the present invention will be described based on the drawings. 1 is a foamed article formed by foaming resin particles made of a copolymerized resin of a polyolefin resin and a vinyl aromatic monomer, and 2 is a urethane resin having elasticity. It is a skin body made of elastic materials such as resin, so-called elastic synthetic resin, rubber, etc., and is wrapped around the outside of the foam 1, and has a predetermined bumper shape as a whole suitable for an automobile. ing.

As a means for wrapping the skin 2 on the outside of the foam 1, a foam 1 corresponding to the internal shape of the skin 2 is molded, and a separately molded skin 2 is attached to the foam 1. In addition to the case where the skin body 2 is formed separately during the molding of the foam body 1.
The outer surface of the foam 1 can be covered with the skin 2 by so-called insert molding, in which the foam is placed in a mold.

In either case, the skin body 2 and the foam body 1 are preferably bonded and integrated by adhesive means.

The skin body 2 is formed to have an open rear part similar to a conventional metal bumper as in the embodiment shown in FIGS. 1 and 2, and a closed rear part as shown in FIGS. 3 and 4. In this case, the rear piece 3 can be molded integrally with the main piece 4 of the front piece (Fig. 3) or separately (Fig. 4). can.

In the case of the integral molding, if a part of the back piece 3 is cut out, the cut part can be opened and the foam body 1 can be attached to the part, and an opening can be formed in a part. The pre-expanded particles can then be filled through the opening to carry out heating and foam molding.

The copolymerized resin of a polyolefin resin and a vinyl aromatic monomer, which is the material of the foam 1, can be obtained by, for example, suspending polyolefin resin particles and a vinyl aromatic monomer in an aqueous medium, and then adding the monomer to the particles. This is a resin obtained by polymerizing both in the presence of a catalyst while absorbing them.

This resin combines shape retention very close to that of polystyrene resin foam, elasticity and toughness similar to polyolefin resin foam, and can exhibit excellent impact resistance.

In particular, when the thermoplastic resin is crosslinked and craft polymerized to a polyolefin resin with a gel concentration of 30 to 80%, the impact resistance of the material itself is further increased and the strength is improved.

In the above, as the polyolefin resin, an ethylene homopolymer or a copolymer mainly composed of ethylene is used, and as the vinyl aromatic monomer, styrene, methylstyrene, etherstyrene, halogenated styrene or these monomers are used. A mixture of a vinyl aromatic monomer and a copolymerizable monomer containing at least % by weight is used.

The foaming ratio of the foam 1 is preferably 10 to 50 times from the viewpoint of shape retention, amount of resin used, etc.

Furthermore, when molding the foam 1, a reinforcing wire mesh 5 such as metal lath is inserted along the inner surface of the mold or along the skin 2 set in the mold, as shown in FIG. A wire mesh 5 can be buried near the surface of the foam 1.

In this case, the shape retention and strength of the foam 1 are further enhanced by the wire mesh 5, making it possible to use a relatively soft resin foam.

Reference numeral 6 denotes an attachment member to the automobile body B, which is set in the mold and integrally fixed when the foam 1 is molded, similarly to the wire mesh 5 described above.

This attachment member is not necessary if some other attachment means are provided.

The automobile bumper A according to the present invention has an elastic material such as an elastic synthetic resin, rubber, etc. on the outside of the foam body 1, which is formed by foaming resin particles made of a copolymerized resin of a polyolefin resin and a vinyl aromatic monomer, as described above. Since it is made by enclosing a skin body 2 molded from a raw material, the whole body is filled with the internal lumpy foam 1, and this internal foam 1 can maintain sufficient shape-retaining power. Even though the skin body 2 has elasticity, it is possible to prevent deformation such as warpage that is inconvenient when installing it on an automobile body.

Since the shape is maintained by the foam 1 in this way, there is no problem even if the skin 2 has elasticity as in the present invention, and the thickness of the skin 2 can be made thinner.

Although the present invention has a solid internal structure, it is much lighter than those made of metal plates because it is mostly made of foam 1 and does not require reinforcement with metal plates. It has become a thing.

Moreover, since the bumper A of the present invention is made of a foam body 1 with a molded interior and the skin body 2 on the outside thereof has elasticity itself, the elasticity of the skin body 2 and the elasticity of the foam body 1 are combined in the event of a collision. Due to its properties, it can effectively absorb impact energy and exhibit excellent cushioning effects.

In particular, in the case of the present invention, since the internal foam 1 is foam-molded from copolymerized resin particles of a polyolefin-based resin and a vinyl aromatic monomer, the material is a combination of the polyolefin-based resin foam and polyethylene. It has properties intermediate to those of polystyrene foam, is neither brittle like polystyrene foam nor too flexible like polyethylene foam, and has moderate shape retention similar to polystyrene foam.
In particular, it has sufficient shape retention to maintain its shape as a bumper, and is also slightly harder than polyolefin resin foam, possessing sufficient elasticity (resilience) and toughness, and therefore has good impact resistance. The outer skin body 2 is also made of an elastic material such as elastic synthetic resin or rubber, which itself has toughness and excellent impact resistance. Therefore, it not only has an excellent impact absorption effect as Bumper A, but also will not be destroyed by a relatively minor impact, for example, a collision that causes partial denting or bending, and will not cause dents or damage at the collision location. The bending is immediately restored and disappears due to the elasticity of the foam 1 and the skin 2, and the durability of this type of bumper A can be increased.

Moreover, if the foam is made of the copolymer resin, there is no risk of rainwater or the like penetrating even if there are holes in the skin.

Furthermore, since the skin 2 is wrapped around the outside of the foam 1, the foam 1 can be protected by the skin 2, and the surface is less likely to be scratched, maintaining a good appearance.

If the skin body 2 is made of urethane resin,
It has excellent weather resistance and there is no risk of discoloration or deterioration.

Furthermore, it is not difficult to wrap the skin body 2 on the outside of the foam body 1, and the wrapping work is easy to perform, and the shape of the skin body 2 can be freely selected, thereby improving the aesthetic appearance of the bumper. Can be done.

As described above, the present invention has great industrial utility as a bumper for automobiles that is lightweight, has good shape retention, is resistant to breakage under slight impacts, and has excellent impact resistance and shock absorption effects. It is.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of the same, and FIGS. 3 to 5 are sectional views showing different embodiments. 1... Foam, 2... Skin body, 5...
...Wire mesh, A...Bumper, B...
・Car body.

Claims (1)

[Claims for Utility Model Registration] 1. A bottom-shaped skin made of an elastic material such as an elastic synthetic resin or rubber on the outside of a foam formed from copolymerized resin particles of a polyolefin resin and a vinyl aromatic monomer. A car bumper that is characterized by covering the body. 2. The automobile bumper according to claim 1, wherein the skin body is molded from an elastic urethane resin. 3. The automobile bumper according to claim 1, wherein the polyolefin resin is an ethylene homopolymer or a copolymer mainly composed of ethylene. 4 Utility model registration claims that are a mixture of a vinyl-1 group monomer, styrene, methylstyrene, ethylstyrene, halogenated styrene, or a vinyl aromatic monomer containing 50% by weight or more of these monomers and a copolymerizable monomer. The bumper of the automobile described in paragraph 1. 5. Any of the claims 1, 2, 3, or 4 for which the foam is formed by embedding a wire mesh such as metal lath in the vicinity of the skin of the automobile as defined in paragraph 1. bumper.