Filling structure

Abstract

A filling structure 10 is a structure in which a filling material 12 having a higher impact energy absorbing performance is inserted into the inner part of a hollow member 11, and the filling material 12 so inserted is fixed to the hollow member 11 with an adhesive layer 13 resulting when the filling material 12 is heated to expand and is cooled to set thereafter.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a filling structure which is preferable for application to a vehicle body frame, in particular, to a bumper, a front side member and a pillar. [0003] 2. Description of the Related Art [0004] In recent years, there have been made attempts to improve the collision energy absorbing performance at the location of a certain vehicle body structural member by filling a material having a superior energy absorbing performance in the inner part of the structural member such as disclosed in JP-A-8-164869 [0005] The patent literature of JP-A-8-164869 discloses a technique described in its paragraph [0015] such as to state, “according to an embodiment shown in FIG. 1, an impact absorbing frame member 5 made up of the frame portion 51 constituted by an angular pipe stock and an expanded aluminum 52 filled in the inner part thereof is constructed by adding predetermined amounts of a thickener and a...

AI Technical Summary

Benefits of technology

[0010] It is an object of this invention to provide a filling structure which allows a filling material such as expanded aluminum to be bonded rigidly to a hollow member whereby secures corrosion resistance thereof.

[0011] According to a first aspect of the invention, there is provided a filling structure comprising a hollow member and a filling material filled in the inner part of the hollow member, the filling material having a higher impact energy absorbing performance, wherein the filling material is fixed to the hollow member with an adhesive having a property that the adhesive expands when heated.

[0020] According to the second aspect of the invention, since the adhesive is adopted which has the property that the adhesive melts and expands by being heated for 10 to 30 minutes at a temperature of 140° C. to 190° C. and sets when cooled thereafter, the adhesive is allowed to melt, expand and set in the process of drying the coating film in a drying oven after the electro-deposition coating. As a result, there is provided an advantage that the process of the adhesive can be implemented by making use of the existing drying oven without providing an additional heating unit.

[0021] According to the third aspect of the invention, since the adhesive is adopted which has the property that the adhesive expands in volume by at least 10%, in a case where an adhesive is additionally provided in a filling material, so that the filling material is then inserted into a hollow member, a gap in a sufficient size can be secured between the hollow member and the filling material. As a result, a treatment liquid is allowed to easily flow between the hollow member and the filling material while a corrosion protection treatment is being carried out so as to ensure the formation of a film to which the corrosion protection treatment has been applied, thereby making it possible to secure the corrosion resistance on the inner part surfaced of the hollow member.

[0022] According to the fourth aspect of the invention, since the sheet-like adhesive is adopted, the handling of the adhesive becomes easy, and a required size of adhesive can be affixed to a required location on the filling material in an easy fashion.

Problems solved by technology

Therefore, when the force is applied thereto, the surface tends to be damaged, and the joining force is decreased, whereby a gap might be formed between the frame portion 5 and the expanded aluminum 52 after a long time period of use.

Under such an environment or a corrosion environment where the water containing the snow-melting salt penetrates between the filling material and the hollow member, there is a possibility that corrosion might occur in the sheet-steel member where said corrosion propagates from the inner part of the member, which ends up being an open hole rust, unless any appropriate corrosion protection treatment, such as formation treatment, or electro-deposition coating, is applied to the sheet steel member, specifically, to the hollow member thereof.

Furthermore, there is also a possibility that a galvanic corrosion might be made due to the contact of a non-treated sheet steel with an aluminum filling material a serious functional deterioration might occur in the aluminum filling material.

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