JPH0248431Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to the structure of a joint between iron and aluminum materials in an automobile body, chassis, etc.

(Prior Art) Conventionally, in order to reduce the weight of automobiles, for example, as described in "SAE Paper 830094",
The idea is to make the car body entirely out of aluminum.

In this case, the weight can be reduced, but the cross-sectional shape becomes large in order to ensure a predetermined strength, and the ground clearance and cabin space affect visibility.

Therefore, as a means of solving this problem, parts that require strength are made of iron-based metals, and parts that do not require relatively strength or where a large cross-sectional shape is acceptable are made of aluminum. A method of using a mixture of iron and aluminum materials has been considered.

(Problem that the invention aims to solve) However, when such iron and aluminum materials are mixed and used, if there is water adhering to the part where the two materials are joined, the potential difference between the two materials will cause problems between the two materials. There was a problem in that a current was generated (flowing from the aluminum material to the iron material) and the aluminum material corroded (electrolytic corrosion).

(Means for Solving the Problems) The present invention aims to prevent corrosion of the aluminum material at the joining site between the iron material and the aluminum material as described above by a simple means.

To achieve this objective, in the present invention, a non-conductive adhesive is applied between the contact portion of the iron material and the aluminum material to prevent direct contact between the two materials, and the two materials are fastened at the contact portion. The fixture is made of a ferrous material, and the surface of the fixture is coated with a non-conductive material.

(Function) To explain the means of joining the two materials in the joint structure of the iron material and aluminum material of the present invention, first, non-conductive adhesive is applied to the contact area of the two materials in the joint portion of the iron material and aluminum material. Apply the material and glue the contact areas of both materials together.

Next, this part is fastened with a fixture made of an iron-based material whose surface, at least in contact with the aluminum material, is coated with a non-conductive material.
Note that this fixture refers to members for fastening such as bolts, nuts, rivets, and bolts.

In the structure of the present invention that is connected in this way, even if water adheres to this part, the contact area between the iron material and the aluminum material is provided with a non-conductive adhesive between the two. No corrosion current occurs.

Further, since the surface of the fixture is coated between the fixture and the aluminum material, no corrosion current is generated between the fixture and the aluminum material.

By the way, when fastening the fastener, the fastening work is performed by rotating or hammering the fastener, so it is possible that the coating may be damaged by burrs around the hole and a part of the coating may be torn due to the fastening work. If the part where the coating is torn in this way is exposed to a corrosive environment due to water intrusion, etc.
Corrosion current flows from the aluminum material to the ferrous material fixture. However, the area of the fixture that accepts this corrosion current is smaller than that of the aluminum material, so the corrosion current that occurs there is That is, compared to the corrosion current flowing from a small-area fixture to a large-area iron material, the amount of corrosion current is extremely small, and corrosion of the aluminum material is extremely small.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the configuration of the embodiment will be explained.

FIG. 1 is a cross-sectional view showing the joint structure of iron and aluminum materials according to the first embodiment of the present invention. In the figure, 10 indicates a pillar (steel material), and this pillar 10 is a high-strength member at the rear of the vehicle body. It is installed in places where strength is required, and is made of iron plate (hereinafter referred to as steel plate) and is formed into a box cross-sectional shape as shown in the figure, and the surface is coated with cation electrophoresis to further improve corrosion resistance. Painted with paint.

A back panel (aluminum material) 20 is coupled to the flange portion 11 of this pillar 10.
This back panel 20 separates the vehicle interior 1 and the vehicle body space 2 behind it, and since it does not require comparatively high strength, it is made of aluminum, thereby reducing the weight of the vehicle body.

At the joint portion between the pillar 10 and the back panel 20, between the pillar-side contact portion 12 on the surface of the flange portion 11 of the pillar 10 and the back-panel side contact portion 21 of the back panel 20, there are both 12, 21.
An adhesive 30 is applied in layers to prevent direct contact between the two 12 and 21.

The adhesive material 30 is applied to a width of approximately 3 to 5 mm wider than both contact portions 12 and 21, and is made of a non-conductive material.

Further, the pillar 10 and the back panel 20 are
Coupling holes 13 and 22 in both contact parts 12 and 21
are formed, and rivets (fixing tools) 40 are caulked into these holes 13 and 22 to connect them. This rivet 40 is made of iron or a ferrous material such as steel or stainless steel, the surface of which is coated with a coating material 50 made of a non-conductive material, the head 41 is in contact with the back panel, and the pillar 2
The tip 42 on the 0 side is caulked.

FIG. 2 is a sectional view showing the coating material 50 of the rivet 40.
0 is composed of a base layer 51 formed on the side of the rivet 40 and made of an inorganic material mixed with particles of aluminum or zinc, and a surface layer 52 formed on the outside thereof made of an organic resin material.

Next, the operation of the embodiment will be explained.

(a) At the time of joining To explain the joining of the pillar 10 and the back panel 20 step by step, the pillar side contact portion 12 and the back panel side contact portion 21 are bonded in an area approximately 3 to 5 mm wider than both contact portions 12 and 21. Apply material 30,
Both 12 and 21 are glued together.

Next, the rivet 40 is inserted into the coupling holes 13 and 22 of both 10 and 20, and the tip 42 of the rivet 40 on the pillar 10 side is caulked to couple the two.

(b) When water enters the joint In the joint structure of this embodiment, even if this part is exposed to a corrosive environment due to adhesion of water, the steel pillar-side contact part 12 and the aluminum back panel-side contact part 21 can be easily connected. Since a non-conductive adhesive 30 is applied between them, no corrosion current is generated between them 12 and 21. In addition, since the adhesive 30 is applied over a wider area than both contact parts 12 and 21, even if water adheres to the tip of the flange part 11 of the pillar 10 or the end face of the back panel 20, corrosion current will not be generated. is difficult to occur.

Furthermore, since the surface of the rivet 40 is coated with a non-conductive coating material 50 between the rivet 40 and the back panel 20, no corrosion current is generated between the two.

By the way, the coating material 50 may be torn due to the work of caulking the rivet 40, but in this embodiment, since the coating material 50 is caulked from the pillar 10 side,
Even if the coating material 50 on the 0 side is torn, no corrosion current will occur because the rivet 40 and the pillar 10 are both iron-based and have approximately the same potential.

In addition, as shown in Figure 3a, if the rivet 4
0's back panel 20 side has tears 53, 53, 53
occurs, and when this tear 53 is exposed to a corrosive environment, a corrosion current i flows from the aluminum back panel 20 side to the iron-based rivet 40 side. However, since the area of the rivet 40 that accepts this corrosion current i is smaller than that of the back panel (aluminum material) 20, the corrosion current i will flow from the large area side to the small area side, and the flow of the corrosion current i will be very small, causing corrosion. Progress is extremely slow.

Incidentally, in FIG. b, contrary to the embodiment, a small-area rivet 400 is formed of aluminum, and a tear 5 in the coating 500 is formed from this rivet 400.
This shows a case where a corrosion current i is generated in a large-area iron material 100 through
The corrosion current i flows endlessly, and the aluminum-based rivet 400 corrodes and disappears.

As explained above, in the structure of the joint between the iron material and the aluminum material in the first embodiment, the contact portions 12 and 21 between the pillar 10 and the back panel 20 are
An adhesive 30 is provided between them, and a rivet 40 is provided between them.
Since the coating material 50 is provided on the surface of the aluminum back panel 20, corrosion current will flow from the aluminum back panel 20 to the iron-based pillars 10 and rivets 40 even if this joint is exposed to a corrosive environment due to water infiltration. Therefore, the effect of preventing corrosion of the back panel 20 can be obtained.

In addition, in case the rivet 40 has a coating material of 50
Even if a tear 53 occurs and the rivet 40 is exposed to a corrosive environment, since the rivet 40 is made of iron-based material, the corrosion current i generated there is extremely small and corrosion can be suppressed. Effects can be obtained.

Next, a second embodiment shown in FIGS. 4 and 5 will be described. Incidentally, in explaining the second embodiment, the explanation of the same structure and operation as the first embodiment will be omitted.

FIG. 4 is a perspective view showing a portion employing the structure of the second embodiment, and 60 indicates a member of the vehicle body made of steel. An aluminum bumper reinforcement 70 is attached to a bolt 81 on an iron mounting bracket 61 provided at the tip of this member 60.
and a nut 82.

FIG. 5 is a cross-sectional view taken from FIG. Holes 63 and 72 are opened.

Further, the bolt 81 and the nut 82 are made of iron, and the surfaces are coated with the same coating as in the first embodiment, and between the head 83 of the bolt 81 and the bumper reinforcement 70, there is a A washer 84 whose surface is coated with the same coating material 50 as in the example is interposed.

The bolt 81 and nut 82 are fastened by rotating the nut 82 on the mounting bracket 61 side, which is made of iron. This makes it difficult for the coating material 50 of the washer 84 to be torn during the fastening operation.

Furthermore, even if the threaded part or the plating of the nut breaks when tightening the nut 82 to the bolt 81, the mounting bracket 61, the bolt 81, and the nut 82 are all made of iron, so no corrosive current will be generated between them, and the aluminum Bumper reinforcement 7 made by
The above method is more effective than performing the fastening work on the 0 side because there is no risk of the plating being torn and a corrosive current being generated from that part.

Bumper reinforcement 70 as in the first embodiment
Since corrosion current is prevented from flowing from the mounting bracket 61 to the bolt 81 and washer 84, corrosion of the bumper rear face 70 is prevented. Moreover, even if the coating material 50 is torn, the corrosion current generated therein is extremely small, and the progress of corrosion is extremely slow. Note that since the washer 84 is coated, there is no zinc-based washer interposed in the part in contact with aluminum, so sacrificial corrosion of zinc does not occur and no looseness occurs in the joint.

Although the embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment. Although we have shown examples in which the devised structure is applied, the invention is not limited to this.
For example, it can be applied to other parts such as the connection between a vehicle body panel and a side sill.

Furthermore, the coating material is not limited to those shown in the examples as long as it is non-conductive.

(Effects of the invention) As explained above, in the joint structure of the invention between iron and aluminum materials, the adhesive applied between the contact parts of the two materials prevents corrosion current from flowing between the contact parts. In addition, the non-conductive material coated on the fixture prevents corrosion current from flowing between the ferrous material fixture and the aluminum material, thereby preventing the aluminum material from corroding. At the same time, even if the coating of the fixing device is torn during the fastening process,
Since the fixture is made of iron-based material so that the corrosion current generated between the aluminum material and the fixture is small, the effect that corrosion does not easily occur in the aluminum material can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the joint structure of iron and aluminum materials in the first embodiment of the present invention, and Fig.
3 is a cross-sectional view showing the main part (coating material) of the structure of the embodiment, FIG. 3 is an explanatory diagram explaining the function of the structure of the first embodiment, and FIG. A perspective view showing the vehicle body attachment part,
FIG. 5 is a sectional view (FIG. 4-) showing the structure of the second embodiment. 10... Pillar (iron material), 20... Back panel (aluminum material), 30... Adhesive material, 40...
...Rivet (fixing device), 50...Coating material,
61...Mounting bracket (iron material), 70...Bumper reinforcement (aluminum material), 81...
Bolt (fixing tool), 82... Nut (fixing tool).

Claims (1)

[Claims for Utility Model Registration] A non-conductive adhesive is applied between the contact portion of the iron material and the aluminum material to prevent direct contact between the two materials, and a fixture is provided to fasten the two materials at the contact portion. ,
A joint structure of iron and aluminum materials, characterized in that it is made of iron-based material and that the surface of the fixture is coated with a non-conductive material.