JPH07124762A - Method for welding parts to plate of aluminum and the like - Google Patents

Abstract

PURPOSE:To weld parts of same quality or different quality to the plate of aluminum, etc., having an oxidized coating film to which it is almost impossible to weld parts by conventional industrial methods. CONSTITUTION:Plural projections 4a whose tip end parts are projecting are provided on the bottom of parts 4, the projections are brought to contact with the plate surface and held between a horn tip 2 and an anvil 3 of an ultrasonic welding equipment and welded applied with selected pressurizing force, electric force and vibrating time by which the projections 4a are allowed to almost completely collapse. At this time, to prevent sticking of the parts 4 and plate 5 to the pressurizing surfaces of the horn tip 2 and anvil 3, the pressurizing surfaces are given non-skid projecting and recessed patterns and both of them are welded in a held state by applying oil whose thickness does not prevent growing of the projecting surface to the parts 4 and plate 5 or mounting a film on the parts 4 and plate 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for welding nuts and bolts of the same material or different materials to a plate surface of a metal having an oxide film such as aluminum.

[0002]

2. Description of the Related Art Sheet materials such as aluminum, zirconium and alloys thereof are used in large quantities for structural purposes. However, the weldability required as a structural material is significantly inferior to that of mild steel. Aluminum has a poor thermal conductivity and a poor viscosity when melted, which is disadvantageous for fusion welding. Resistance welding is also not easy due to the presence of an oxide film having a large electric resistance and the phenomenon of picking up on a pressure electrode (a part of molten metal sticks to the electrode). Since welding between plates is also troublesome as described above, it is much more difficult to weld parts such as nuts to the plate surface because it is out of the applicable range of fusion welding and resistance welding.
The current situation is to leave the contrivances to adhesion and structural design.

[0003]

When a steel plate is used as the structural material, a projection nut can be placed on the plate surface and easily welded by an electric resistance (projection) welder. Therefore, nut welding on the plate surface is essential for assembly. It has become a technology. However, for aluminum plates, the above projection welding is extremely difficult. Even if the protrusions on the lower surface of the nut are melted off, the electrodes do not follow easily because they follow the electrode slowly. The inventors of the present invention have previously opened a way for ultrasonically welding structural aluminum plates that are difficult to resistance-weld to each other, but the present invention is more difficult to weld parts such as nuts to the plate surface. The development of technology was caught as an issue.

[0004]

[Means for Solving the Problems] Initially, an ordinary aluminum nut was placed on the surface of an aluminum plate, and various pressures, electric powers, and vibration times of the ultrasonic welding machine were changed and tested, but all were unsuccessful. Therefore, when the experiment was continued with the aluminum foil sandwiched between the plate surface and the nut, it was possible to tentatively weld. However, this is a kind of brazing, not welding, and the strength is weak. Therefore, when an aluminum nut with a lower surface protrusion having the same shape as that of a mild steel projection nut was experimentally manufactured and tested, it was possible to weld it by appropriately selecting welding conditions such as pressing force. Before the experiment, we thought that it would be difficult to join the nut and the plate surface by vibrating friction, because if the protrusion is provided on the lower surface of the nut, the relative slip is suppressed more than the anti-slip concave and convex pattern on the lower surface of the horn tip, but the result is the opposite. It was

The thus obtained method for welding parts to a plate surface of aluminum or the like according to the present invention is a method of welding parts of the same material or different materials to a plate surface of aluminum or the like having an oxide film. A plurality of pointed protrusions are provided on the surface to be welded, and the protrusions are applied to the plate surface, sandwiched between the horn tip of the ultrasonic welding machine and the anvil, and welded so that the protrusions are almost completely crushed. The feature is that welding is performed by selecting the pressing force of the machine, electric power, and vibration time. The pressing surface of the horn tip and anvil has a non-slip concave and convex pattern, and the convex surface has a thickness that does not prevent it from biting into the object to be welded. It is characterized by

[0006]

[Operation] The principle of welding a steel projection nut onto a steel plate, which is a well-known technique, is to concentrate a large current on the contact portion between the projection on the lower surface of the nut and the plate surface to raise the temperature in the vicinity.
The resistance is increased by the temperature rise, and the temperature is raised to the inside, and the projection base and the plate surface are pressure bonded. The reason why the principle is not applicable in the case of aluminum is that there is an oxide film on the surface of aluminum having high electric resistance, the melting point is low, the melting speed is high, and the resistance does not increase even if the temperature is raised. The projections on the bottom surface of the nut, which are extremely effective for resistance welding with steel plates, are worthless with aluminum plates and nuts.

However, it has been found that the projections on the lower surface of the nut, which have no value in resistance welding, work fine in ultrasonic welding. That is, since the nut is made of a harder material than the plate material, the protrusions on the lower surface crush the oxide film on the plate surface and soften it by frictional heat after scratching. Even if it is softened and crushed, it is interposed between the plate and the nut to mediate friction and heat the two so that they can be joined. In addition, when welding an aluminum welded object with an ultrasonic welding machine, there was a problem that the welded object was fixed to the horn tip or anvil of the welding machine, but this is the horn tip, the pressure surface of the anvil has an uneven pattern, Lightly apply oil as an organic layer on it, or put it in the form of a film,
It can be solved by holding the object to be welded. If the oil or film is thin, hold the anti-slip action of the uneven pattern,
Sticking can be prevented by organic substances.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the implementation of the present invention. 1 in the figure
Is a horn of an ultrasonic welding machine, 2 is a horn tip (tool), 3 is an anvil, 4 is a hexagonal nut made of aluminum with a protrusion as a component, and 5 is an aluminum plate. The nut 4 is shown in FIGS. 2 and 3, and the appearance thereof is similar to that of a steel projection nut, and projections 4a are provided at three positions. The protrusion 4a in this example is composed of an extension portion of the side surface of the nut and a conical inclined surface rising from the lower surface of the nut.

The experimental data will be described later, but the nut 4 is shown in FIG.
The surface of the aluminum plate 5 peeled off after welding is shown. The welding position of the nut 4 is indicated by a chain line as 4 '. The peeling marks 6 (recesses) on the three protrusions 4a are projected from the nut welding position 4'to the outside. This is because the lower surface of the nut with the projection 4a spreads outward during welding. It is not always the case that the peeling marks 6 are always welded equally, and in the experiment, one peeling mark 6 was merely a depression once every three times, and it was not a rough surface peeled after welding. However, in subsequent experiments, it was found that if the projections 4a on the lower surface of the nut were made slightly smaller and the number was increased to 6, the welding would always occur at all projection positions.

Between the peeling traces 6 of the protrusions of FIG. For some reason, it is slightly separated from the protrusion peeling mark 6, but it is certainly a rough surface that is once welded and peeled off. Although the illustration is omitted, the peeling surface on the nut side is the same. The area of the peeled mark 7 on the flat welded portion varied from experiment to experiment. A protrusion 4 having a different shape from the protrusion 4a on the bottom surface of the nut
b is shown in FIGS. The protrusion 4b rises from the lower surface of the nut 4 like an arcuate mountain range. The welding result is shown in Fig. 4.
This is almost the same as the above except that the peeling trace 6 of the protruding portion is slightly moved to the inner side and becomes elongated, and the peeling trace 7 of the flat weld portion is narrowed. It is not possible to make the arc-shaped projection 4b into a completely circular shape that is not divided, and it seems that the projection should not be too large. It may depend on the welding conditions.

The horn tip 2 and the anvil 3 shown in FIG. 1 are made of heat-treated high-speed steel or cemented carbide.
These are often the case where the product is stuck and difficult to remove even if an aluminum product is held and welded and then the product is taken out. This is called a chip stick or a sticking phenomenon. In order to prevent this, the non-slip concavo-convex pattern as shown in FIG. 7 is provided on the pressing surface of the horn tip 2 or the anvil 3 by the method previously developed by the present inventors for welding aluminum plates to each other, and the projections The part cuts into the object to be welded to suppress the friction due to the relative movement, and the sticking phenomenon is prevented by applying oil or interposing an organic material layer on which a film is placed so as not to hinder the above-mentioned cutting. FIG. 8 is an enlarged cross-sectional view of an example of the concavo-convex pattern 8, in which the organic layer 9 coated with oil is shown by a solid line and the chain is shown by an organic layer 10 on which a film is placed. The best oil for preventing the sticking phenomenon was soybean oil and press oil, and the film for the organic material layer 10 was cellophane tape.

The experiment was conducted with an American ultrasonic welding machine (15 KH
Z, 4500 W), but a typical one is described below. The nut is the hexagonal nut shown in FIGS. 2 and 3, and the material is JIS A6061 T-6 heat treated or work hardened. The dimensions are diagonal length 15 mm, height 6 mm, and protrusion 4
The height of a is 1.5 m. The material of the aluminum plate is JI
S A5182P-0, plate thickness 2.0 mm. Welding conditions are applied pressure of 40 PSI (2.8 kg / cm ² ) and joining (vibration)
The time of 2.0 seconds is common and only 2500W is used.
3 pieces of 2300W, 5 pieces of 2200W, 2000W
14 welding test pieces were prepared, and the torque test and the peeling test were performed. In the torque test, the nut is twisted off the plate surface, and in the peeling test, the nut is peeled off vertically.

The results of the torque test are shown in Table 1.

[Table 1]

The results of the peel test are shown in Table 2.

[Table 2]

In the above test results, one having weak strength is one in which three of the protrusion peeling marks 6 are not welded. However, since the welding area of the peeled trace 7 of the flat welded portion also varies, it is considered that the variation in strength has increased as described above. There may have been a problem in the selection of welding conditions due to inexperience. As described above, when a few test nuts were made by slightly welding the nut projections 4a shown in FIGS. 2 and 3 at all six corners instead of the three corners, the welding test showed that the strength was stable. The peeled surface was shown, but the data was not in time for this application. Summing up the above,
The method of welding parts to a plate surface of aluminum or the like of the present invention is
It can be judged that it is practically possible in the future. The embodiments of the present invention are not limited to the above-mentioned embodiments, and needless to say, can be variously modified and applied, and the plate material can be a plate with zirconium or other oxide film, and the parts can be different materials capable of ultrasonic welding. It can be applied to bolts, bolts and similar parts.

[0016]

INDUSTRIAL APPLICABILITY The present invention can be applied to both fusion welding and resistance welding.
For the first time, it was possible to weld parts to aluminum plates, which was nearly impossible in the industry, by adopting ultrasonic welding. Protruded parts are well known for mild steel projection welding nuts, but they are limited to mild steel nuts, and no engineer was conceived of an aluminum prominent nut. However, this invention has demonstrated that the projection of the nut enables welding of the aluminum plate and the nut by ultrasonic welding. It is thought that the projections of parts that are harder than aluminum plates have a large effect of destroying the oxide film on the plate surface, but the projections that do not work in resistance welding work unexpectedly in ultrasonic welding. The present invention also disclosed a simple method for avoiding the fixing of an aluminum product that is easily fixed to the horn tip or anvil of an ultrasonic welding machine. This invention is only a starting point, and it is expected that ultrasonic welding will greatly expand in the future as a means for welding parts to the plate surface.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an example of an implementation device of the present invention.

FIG. 2 is a vertical sectional view of an embodiment of a nut with a protrusion.

FIG. 3 is a bottom view of FIG.

FIG. 4 is a plan view of a welding nut peeling trace.

FIG. 5 is a vertical sectional view of another embodiment of the nut with protrusion.

6 is a bottom view of FIG.

FIG. 7 is a plan view of an example of a non-slip uneven pattern.

8 is an enlarged sectional view of FIG.

[Explanation of symbols]

 4 Nuts (parts) 4a Protrusion 4b Protrusion 5 Aluminum plate

Front page continued (72) Inventor Hisao Matsuoka 2-15-5 Sotokanda, Chiyoda-ku, Tokyo Nakakatani Co., Ltd. (72) Inventor Hiroshi Suguri 2-15-5 Sotokanda, Chiyoda-ku, Tokyo Stock company In Nakatani (72) Inventor Hitoshi Kamtake 2-15-5 Sotokanda, Chiyoda-ku, Tokyo Inside Nakatani Co., Ltd.

Claims (2)

[Claims] 1. A method for welding parts of the same material or different materials to a plate surface such as aluminum having an oxide film, wherein a plurality of pointed projections are provided on the planned welding surface of the parts, and these projections are provided. Aluminium, which is applied to the plate surface, sandwiched between the horn tip of an ultrasonic welding machine and an anvil, and the welding pressure, power, and vibration time of the welding machine are selected so that the projections are almost completely crushed. How to weld parts to plate surface. 2. The welding method according to claim 1, wherein the pressing surface of the horn tip and the anvil has a non-slip uneven pattern, and the convex surface has a thickness that does not prevent it from biting into the object to be welded. A method for welding a component to a plate surface of aluminum or the like, which comprises coating or placing a layer and sandwiching the plate and the component.