JPS61176479A - Method and device for butt resistance welding of thin plate - Google Patents

Abstract

PURPOSE:To increase a welding strength with preventing buckling at the butt end part of a thin plate by impressing the butt load of high pressure of the second step further in case of performing a resistance welding with impressing the initial stage butt load of the first step on the butt end part. CONSTITUTION:The initial stage butt load is impressed on the butt part 3 of a thin plate 2 simultaneously with setting by a fixed clamp 5, mobile clamp 7 and weight 19. When a welding current is passed to the projecting part of the butt part 3 thereof, the fixed york 12 of the electromagnetic pressurizing device 11 which is provided in this electric system is excited and the magnetic force to attract the mobile york 14 is actuated. And the load of the second step of the electromagnetic pressure in addition to the initial stage load of the first step by the weight 19 is impressed on the slider 9 of the mobile clamp 7 against the fixed clamp 5. The plastic flow of the molten metal is thus caused on the butt part 3 and the residual components of the molten metal of oxides, etc. are pushed out to the side part of the butt part 3 and high welding strength is obtd.

Description

[Detailed description of the invention] Industrial application field> The disclosed technology is applicable to a plate having a width of 10 mm and a thickness of 0.5 mm. It belongs to the technical field of butt welding thin steel plates such as Ies by resistance welding.

Thus, the invention of this application is used, for example, in continuously variable transmissions for automobiles. A method of resistance welding by creating plastic flow of molten metal at the butt portions of the thin plates at both ends, when butt welding the ends of thin plates used for power transmission steel belts, etc. ,as well as,
The invention relates to an apparatus directly used in the method, and in particular,
The abutting ends of the pair of thin plates are held by a fixed clamp and a movable clamp, and an initial load is applied between the butt and the fixed clamp by the first stage load application device, and then the two thin plates are A method for butt resistance welding of thin plates in which a welding current is applied to the butt portion and a second high-voltage butt load is applied using an electromagnetic pressure device or the like to generate plastic flow and obtain high welding strength, and the method This invention relates to a device that is directly used for.

<Prior art 5 As is well known, there are various methods of welding metals together, but for example, when welding thin plates together, surface welding due to polymerization creates a stepped portion and is not suitable for the intended use of the parts. For example, belts for power generation of automobiles, which have recently been developed as a new technology, such as steel belts used in continuously variable transmissions, have a plate width of 5 to 20 mm.
For plates with a thickness of approximately 0.1 to 0.3 mm, there is a restriction that lap welding cannot be performed at both ends, so naturally butt welding must be performed, and the steel as a product Considering the high tensile stress during belt operation, the strength of the butt weld must be considerably high.

As mentioned above, laser beam welding or electron beam welding can be applied under the special conditions of the above-mentioned size for butt welding of thin plates whose thickness is extremely thin compared to the width of the plate, and welding joints are possible. However, since this type of welding is a type of fusion welding, the solidified structure of the molten metal remains after welding, and in order to satisfy the high strength requirements of steel belts as mentioned above, it is difficult to Processing such as ring roll rolling and heat treatment are required in the process.

Therefore, even if it is possible to obtain the desired required strength for single products, there are problems in that the number of processing steps is large and production efficiency is low.Furthermore, there are problems in strength such as blowholes, etc. The drawback is that reproducibility with the same precision cannot be expected.

<Problems to be solved by the invention> To solve this problem, it is possible to use butt resistance welding to conduct a large current in an extremely short period of time to achieve instantaneous bonding, but the prerequisite is that the sheet width is If the pressure is extremely thin compared to the
Even if the resistance welding is performed at m, the initially applied high pressure necessary for resistance welding causes buckling of the abutted ends, making it impossible to perform butt resistance welding.

For example, as shown in the invention disclosed in Japanese Patent Publication No. 56-53465, plastic flow is caused in the molten metal of the butt resistance welded part of the metal material after welding current conduction, so that the solidified composition of the molten metal remains. Even if we try to apply a technology that produces almost no welding distortion, has high reproducibility, and has good productivity, as mentioned above, very thin plates will buckle due to the large initial applied load. The negative point was that it was unavoidable and could not be applied in practice.

The purpose of the invention of this application is to solve the technical problem of butt resistance welding of thin plates whose thickness is extremely thin compared to the plate width based on the above-mentioned prior art, and Utilizing instantaneous plastic flow technology,
In addition, we have developed an excellent butt resistance welding method for thin plates, which causes this by applying a load that mimics the conduction current of resistance welding, and which is beneficial to the application of metal thin plate technology in various machine manufacturing industries, and an apparatus that can be directly used in the method. This is what we intend to provide.

<Means/effects for solving the problem> In order to solve the above-mentioned problem, the structure of the invention of this application, which is based on the scope of the above-mentioned patent claims, is to solve the above-mentioned problem. When performing butt resistance welding, the other end is supported by butting with a fixed clamp, and first, with the initial load of the first stage applied, a predetermined large current is conducted for a momentary and extremely short period of time. The ends of both thin plates are joined by generating molten metal and causing plastic flow in the molten metal by means such as second-stage electromagnetic pressure and extruding it to the side near the butt part. Therefore, the butt resistance welding part has little welding distortion and no solidified composition of the molten metal remains, so that a sound weld with high welding strength can be obtained. Although the protrusion amount is short at both ends, technical measures have been taken to prevent buckling.

<Embodiment - Configuration> Next, one embodiment of the invention of this application will be described below with reference to the drawings.

Reference numeral 1 denotes a butt resistance welding device for thin plates, which constitutes the gist of the invention of this application, and in this embodiment, it performs resistance welding of butts 3 of thin plates 2 forming a steel belt of a continuously variable transmission of an automobile. The thin plate 2 is, for example,
It is a thin tape-like material with a width of 5 to 20 mm and a thickness of 0.1 to 0.3 nm.

On one side of the plate 4 provided on the base (not shown), a fixing clamp 5 for the thin plate 2 has an upper clamp 6 for tightening and fixing the thin plate, which can be freely removed with a bolt. A movable clamp 7 is attached to the fixed clamp 5, and as shown in FIG. It can be tightened freely.

Therefore, as shown in FIGS. 1 and 1.2, the thin plate 2 is tightened and fixed to the stationary clamp 5 and the movable clamp 7 with their abutments 3 facing each other in a loop shape.

Further, as shown in the figure, the movable clamp 1 can be freely moved toward and away from the fixed clamp 5 by a small distance via a slider 9.

An electromagnetic pressurizing device 11 is provided at a set distance from the fixed clamp 5 in the length direction, and a fixed yoke 12 provided on the plate 4 has an excitation part 13. On the other hand, a movable yoke 19 is provided at a set distance from the fixed yoke 12 so as to be able to move toward and away from the plate 4 via rollers, and a wire 15 having one end fixed to the movable yoke 14 is attached to the plate 4. It is engaged with the roller 17 of a roller assembly W116 installed upright at the other end, extends, bends and hangs down, and is loosely inserted into the insertion hole 18 of the plate 4, and the other end is connected to the weight 19.

Further, another wire 15 has its tip connected and fixed to the movable yoke 14, and the other wire 15 loosely inserts into a guide hole 20 formed in the fixed clamp 5 in the longitudinal direction. As shown in FIG. 2, the proximal end thereof is connected and fixed to the slider 9 of the movable clamp 7.

Therefore, a force is always applied to the slider 9 of the movable clamp 7 by the weight 19 via the movable yoke 14 and the wire 15.15 so that it approaches the fixed clamp 5 side. As shown in FIG. 5, an initial butt load is applied to the abutting portion 3 at the same time as setting.

In this case, the protrusion at the butt portion 3 of the thin plate 2 is 0.
It is extremely small at 2 to 0.5 mm, and is designed so that buckling or the like does not occur in the butt portion 3 due to the initial load due to the weight 19.

In the butt resistance welding equipment@1, the fixed clamp 5, the movable clamp 7, and the fixed yoke 13 of the electromagnetic pressurizing device 11 are It is connected to the excitation coil 23, and therefore, when welding current is applied to this circuit, the welding current is applied to the protrusion of the butt 3 of the thin plate 2 via the fixed clamp 5 and the movable clamp 7, and the electromagnetic pressure device The fixed yoke 12 of 11 is excited and a magnetic force that attracts the movable yoke 14 acts, and the slider 9 of the movable clamp 7 relative to the fixed clamp 5 is subjected to the initial load of the first stage by the weight 19 and the first stage of electromagnetic pressure. The second stage load is applied, and in this state, as shown in Fig. 7, for the applied welding current i, the second stage load is The electromagnetic pressure load F is applied in accordance with the welding current.

<Embodiment - Effect> In the above-described configuration, the thin plate 2 is press-clamped to the slider 9 of the fixed clamp 5 and the movable clamp 7 via the upper clamp 6.10, respectively, and the abutting portion 3 is set, for example, by a protrusion amount of 0. 2 to 0.5 em, and the weight 19 is suspended from the tip of the wire 15 at time t1 on the horizontal axis time t in FIG. Apply f to set.

In Fig. 7, the circuit is closed at 12:00 and a large resistance welding current i of 1 to 3 KA/1I112 is applied during a short period of time from 2 to t3, for example, from 4 to 8+e+a seconds.
are electrically connected, and butt resistance welding is performed on the butt portion 3 of the thin plate 2.

During this time, as shown in FIG. 7, while the butt resistance welding of the butt portions 3 is being performed, the electromagnetic pressurizing device 11 also operates the movable yoke because the fixed yoke 13 is excited by the coil 23. A second stage electromagnetic pressure F is applied to 14, and the molten metal of the abutting portion 3 is instantly
A large load of +1/am2 is applied to.

Therefore, as shown in Fig. 6, plastic flow of the molten metal occurs at the abutment part 3 and is pushed out to the side of the abutment 3, and residual components of the molten metal such as oxides are pushed out to the side. It will be.

Incidentally, since the electromagnetic pressure F is applied instantaneously and in the second stage, only the molten metal flows plastically and is pushed out to the side.

Then, when the welding current flowing through the circuit is cut off and disappears, the second stage electromagnetic pressure load F applied to the welded part butt 3 disappears following this, as shown in Fig. 7. However, only the initial load of the first stage due to the weight 19 is applied.

The initial load by this first stage weight 19 assists in curing the weld metal of the butt portion 3.

Therefore, by applying the electromagnetic pressure in the second stage, the joint surface of the abutting portion 3 is expanded, the temperature distribution is averaged, the joint surface becomes flat, the plastic flow acts greatly, and as a result, the Welding strength will be obtained.

After the butt resistance welding is completed, the weight 19 is removed from the wire 15, and the fixing clamp 5 and the electromagnetic pressure 7 are removed.
The loop-shaped thin plate 2 which has been welded and joined at the abutting part 3 is removed, and the molten metal that is pushed out and protruding from the abutting part 3 by plastic flow is removed by a suitable cutting means such as a grinder, so that the entire surface has the same cross section. A loop-shaped steel belt can be obtained.

In the above embodiment, an electromagnetic pressure device was used as the second stage high voltage butt load application device, but in this embodiment, the second stage high voltage butt load was applied following the welding current conduction. However, the second-stage high-voltage butt load application device or means is mechanical insofar as its response characteristics approximate the welding current to be conducted. A wide variety of means can be adopted.

<Effects of the Invention> As described above, the invention of this application is basically superior in butt resistance welding of thin plates such as steel belts for power transmission used in continuously variable transmissions of automobiles, etc. While performing butt resistance welding, it is possible to increase the welding strength without creating residual structures in the molten metal while preventing buckling at the butt ends, and also guarantees high precision reproducibility. This has the excellent effect of increasing mass productivity and improving work efficiency.

Furthermore, it is possible to generate a large amount of plastic flow near the butt joint surface, which makes the temperature distribution of the joint surface uniform, leaves no solidification structure, and is dependent on the surface shape of the joint surface of the thin plates. The excellent effect of reducing welding distortion and welding distortion is achieved.

Therefore, while applying the first stage initial butt load to the butt ends, by applying the second stage high pressure butt load during butt resistance welding, buckling does not occur and only the molten metal becomes plastic. It can be made to flow and extruded to the side. Therefore, even if the thickness of the thin plate is extremely thin compared to its width, no solidified structure of the molten metal remains without welding distortion, resulting in uniform, high-precision, and sound welding. The excellent effect of

In addition, by using an electromagnetic pressure device when applying the high-voltage butt load in the second stage, it is possible to apply a large high-voltage butt load that mimics the large current applied during butt resistance welding electrically and mechanically. This has the excellent effect of being able to control the initial load, so that only the initial load is applied without causing buckling, and only the molten metal flows plastically and is pushed out to the side, resulting in the above-mentioned The excellent effect of being able to obtain highly accurate welded joints is achieved.

[Brief explanation of the drawing]

The drawing is an explanatory diagram of one embodiment of the invention of this application, and the drawing is a first embodiment of the invention of this application.
The figure is an overall schematic plan view of the device, the second figure is a vertical sectional view of the same, and the third figure is a schematic plan view of the entire device.
．． Figure 4 is a cross-sectional view of Figure 2 m-m and IV-rV, Figure 5 is a plan view of the clamp at the butt part of the thin plates, Figure 6 is a plan view of the molten metal plastic flow state at the butt part of the thin plates, and Figure 7 is a graph showing the relationship between applied current and applied load for butting thin plates. 2... Thin plate, 3... Butt portion, f... Initial butt applied load, F... Second stage high pressure butt load,

Claims (2)

[Claims] (1) In a method of resistance welding by creating plastic flow in the butt portion when performing butt resistance welding of thin plates, initial butt pressure is applied and then current is applied to perform resistance welding, in addition to the initial butt pressure. A method for butt resistance welding of thin plates, characterized in that a second stage of high-pressure butt load is applied to generate plastic flow. (2) In a device used for butt resistance welding of thin plates, a fixed clamp and a movable clamp are provided for the butt ends of a pair of thin plates, and the movable clamp is connected to a first-stage load application device and a second-stage load application device. A butt resistance welding device for thin plates, characterized in that it is connected to an electromagnetic pressurizing device.