JPH01309846A - Bumper filled with foamed body and manufacture thereof - Google Patents

Abstract

PURPOSE:To increase bonding between a foamed member and a tubular body in a bumper in which the tubular body is embedded inside the foamed member installed inside a skin member by setting the foaming density of the foamed member higher on the periphery of the tubular body. CONSTITUTION:A bumper 1 is formed with a skin member 2, a foamed member 3 installed in the inside thereof, and a back plate 4. A tubular body 5 as a reinforcement which extends in the longitudinal direction is provided inside the foamed member 3 and the opening portions 51 on both ends thereof are bonded to the back plate 4. In this case, the foaming density of the foamed member 3 is set higher on the periphery of the tubular body 4 than in the vicinity of the skin member 2. At the time of the foaming of the foamed member 3, cooling air is allowed to flow inside the tubular body 5 to lower the foaming rate of the foamed member 3, increasing its foaming density. Thereby, the bonding strength between the tubular body 4 and the foamed member 3 can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a foam-filled bumper and a method of manufacturing the same.

(Prior art and its problems) In recent years, lightweight foam-filled bumpers have come into widespread use in place of metal bumpers. However, this type of foam-filled bumper lacks structural strength and has the problem of insufficient energy absorption performance in the event of a major collision. For this reason, reinforcement is used when attaching it to the body, but it lacks integrity and
While installation increases the number of man-hours, the reality is that it is not possible to improve energy absorption performance as much as expected. Therefore,
It is proposed that a reinforcement is integrally molded by embedding and fixing a tubular body extending in the longitudinal direction approximately in the center of a foamed member filled inside a skin member that forms the outer shape of the bumper. However, the problem remains that the bonding strength between the tubular body and the foam is insufficient.

(Problems to be Solved) In view of the above conventional problems, the present invention includes a skin member that forms the outer shape of a bumper, a foam member filled inside the skin member, and a foam member that extends in the longitudinal direction approximately at the center of the foam member. In manufacturing a bumper consisting of a tubular body embedded in a foam, an object of the present invention is to improve the energy absorption performance of the bumper by improving the bonding strength between the tubular body and the foam.

(Means for Solving the Problems) The present invention includes a skin member that forms the outer shape of a bumper, a foam member that is filled inside the skin member, and a tubular member that extends in the longitudinal direction and is embedded approximately in the center of the foam member. In a bumper consisting of a body, the foam density around the tubular body is higher than the foam density near the skin member. It can be manufactured by setting the tubular body and foaming the foam member so as to surround the tubular body, by circulating cooling air within the tubular body to reduce the foaming rate around the tubular body. Accordingly, the present invention provides a method of manufacturing a foam-filled bumper.

(Function) According to the present invention, the foam around the tubular body has low foaming, so that the tubular body is firmly held within the foam.

Hereinafter, the present invention will be explained in detail based on specific examples shown in the accompanying drawings.

(Example) Fig. 1 is a central vertical cross-sectional view of a foam-filled bumper according to the present invention, Fig. 2 is a cross-sectional view taken along the line II-II in Fig. 1, and the bumper 1 is a skin member 2 having a U-shaped cross section. The foamed member 3 is provided with a tubular body 5 extending in the longitudinal direction approximately at the center of the cross section, and the backplate 4 It has openings 51.degree. 51 at both ends, projects in an inverted U-shape as a whole, and is connected to the back plate 4 at its ends.

Therefore, as shown in FIG. 4, they may be integrally molded by blow molding, or they may be mechanically connected using bolts and nuts as shown in FIG. Furthermore, the tubular body 5 is not limited to a circular shape, but may have a polygonal shape such as a quadrangular shape, and a metal pipe or a synthetic resin pipe can be used.

The skin member 2 is usually manufactured from urethane, polypropylene, etc., while the foam member 3 is manufactured from urethane, polyethylene, etc.
Foamed resins such as polypropylene, polystyrene, polyethylene/polystyrene are used. Its foaming density is 3rd
As shown in the figure, the height is high around the tubular body 5 and near the skin member 2 and back plate 4;
The back plate 4 is firmly connected to the foam member 3.

The back plate 4 may be provided only at the position where it contacts the stay, and in this case, the structure will be as shown in FIG. 3. Identical members are given the same numbers and their explanations will be omitted.

The foam-filled bumper having the above structure is attached with the tubular body 5 in contact with the body frame near the opening 51 where the tubular body 5 is attached to the back plate 4.

The manufacturing process is as follows.

(2) Apply a degreasing primer to the inner surface of the skin member 2 and the outer surface of the tubular body 5.

(2) Next, the skin member 2 is closed with the back plate 4, and, for example, a two-component urethane mixture is filled inside and foamed.

(2)-H During the foaming reaction, cooling air is passed through the tubular body 5 to suppress foaming around the tubular body 5 and to harden it in a low foaming state. As a result, the density distribution of the foam in the cross section taken along line 1-1 in Figure 1 after foaming and curing was as shown in Figure 3.

(Effects of the Invention) As is clear from the above description, according to the present invention, the skin member forming the outer shape of the bumper, the foam member filled inside the skin member, and the foam member having a longitudinal direction approximately at the center thereof. In a bumper consisting of a tubular body extending in the direction and embedded, the foam density around the tubular body is made greater than the foam density near the skin member, so the tubular body is firmly fixed inside the foam member. As a result, it is possible to obtain a foam-filled bumper that has high energy absorption performance that cannot be obtained with foam even if a thin-walled pipe is used as the tubular body. Further, by attaching it to the stay via a tubular body, the attachment strength can be improved.

Further, according to the method of the present invention, a skin member forming the outer shape of the bumper, a foam member filled inside the skin member,
In manufacturing a bumper consisting of a tubular body extending longitudinally and embedded in approximately the center of a foamed member, cooling air is circulated through the tubular body used as reinforcement during the foaming reaction of the foamed member. Since the foaming rate around the tubular body can be reduced, the foam density around the tubular body can be easily adjusted to be higher than the foam density near the skin member, making it possible to fix the tubular body within the foam member. Assure.

[Brief explanation of the drawing]

FIG. 1 is a central vertical cross-sectional view of the foam-filled bumper according to the present invention, FIG. 2 is a horizontal cross-sectional view taken along the line ■-■, and FIG. FIG. 4 is a cross-sectional view showing another embodiment of the foam-filled bumper according to the present invention, and FIGS. 5 and 6 show the state of connection between the tubular body and the back plate. FIG. ■... Bumper, 2... Skin member, 3... Foamed member, 4... Back plate, 5... Tubular body patent applicant Daikyo Co., Ltd. Haka! Renowned patent attorney Aoyama Aoyama and 2 others - 4;

Claims (1)

[Claims] 1. A skin member forming the outer shape of the bumper, a foam member filled inside the skin member, and a tubular body extending longitudinally and embedded approximately in the center of the foam member. A foam-filled bumper characterized in that the foam density around the tubular body is greater than the foam density near the skin member. 2. A method for manufacturing a bumper comprising a skin member forming the outer shape of the bumper, a foam member filled inside the skin member, and a tubular body extending longitudinally and embedded in approximately the center of the foam member. , a foamed material characterized in that when a tubular body is set inside a skin member and the foamed member is foamed so as to surround the tubular body, the foaming rate around the tubular body is reduced by circulating cooling air within the tubular body. How to make a filled bumper.