JPH0658842B2 - Lead wire welding method for resistors - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistor lead wire welding method for welding a lead wire to a resistor electrode.

2. Description of the Related Art Conventionally, this type of lead wire welding machine has a structure as shown in FIG. 3 and a timing chart as shown in FIG.

In FIG. 3, 1 is a resistor having resistor electrodes 2 on both ends, 3 is a lead wire to be welded to the resistor electrode 2, 4 is a wire chuck for holding the lead wire 3, and one terminal of a welding power source. The cable 5 connected to is connected. 6
Is a fixed electrode that is in contact with the resistor electrode 2, to which the cable 7 connected to the other terminal of the welding power source is connected. Reference numeral 8 is a movable electrode that supports the fixed electrode 6 and the resistor electrode 2.

As the power source, various constant voltage constant time energizing methods are used, and the primary voltage of the welding transformer is changed by visual inspection or by performing a destructive test to inspect the welding strength of the welded part and the welding condition. The quality of welding was judged by monitoring the voltage waveform, and it was judged as a good product or a defective product.

Problems to be Solved by the Invention In such a conventional configuration, the specific resistance value of the electrode wire chuck that holds the lead wire changes due to heating during welding, or the lead wire is removed from the electrode due to the softening wear phenomenon due to heat. The length of the lead wire to be melted (spreading margin) changes in the direction that it becomes longer, and the change in the contact resistance due to the change in the cut surface due to the wear of the blade cutting the lead wire greatly affects the welding strength, The method of monitoring the waveform has a problem in that it cannot be detected until the welding is over-welded to a completely abnormal state and cannot be judged until a defective product is produced.

The present invention solves such a problem, and a welding current energy value is controlled so that the amount of displacement of a lead wire is detected by a sensor as an analog displacement amount and the amount of melting is always constant, and stable welding is performed. The purpose is to obtain strength.

Means for Solving the Problems In order to solve this problem, the present invention uses a DC constant power source as a power source when welding a lead wire to a resistor electrode, and the amount of melting of the lead wire is analog. It is characterized in that the welding current is controlled while being directly detected as a displacement amount by a sensor and compared with a welding target current curve stored in a computer in advance.

Function With this method, the welding target current curve that considers the heat balance between the resistor electrode and the lead wire is stored in the computer so that the lead tip part (extending margin) is optimally melted. The welding current curve is such that the current value is always detected separately on the left and right, and if the amount of melting is small, the current value is increased, and if the speed of melting is too fast, the current value is decreased. The current can be controlled.

Embodiment FIG. 1 and FIG. 2 are timing charts of a lead wire welding method for a resistor according to an embodiment of the present invention, in which a welding start signal is applied to a DC current power source after cutting the lead wire to connect the lead wire 3 and the resistor. In order to confirm the contact with the electrode 2, a weak current is applied to the wire chuck 4 and the fixed electrode 6 through the cables 5 and 7 in FIG. Wire chuck 4
After the contact between the tip lead wire 3 of the and the resistor electrode 2 is detected by the displacement sensor individually on the left and right lead wires 3,
It was confirmed that the welding wire welding curve in Fig. 2 stopped changing temporarily when welding current started to flow, and the tip of the lead wire 3 in Fig. 2 was optimized with a delay of several msec until the lead wire 3 started to melt. The welding target current curve stored in advance in the computer in consideration of the heat balance between the resistor electrode 2 and the lead wire 3 so as to ensure proper melting and the amount of the lead wire 3 melted for each of the left and right lead wires 3 are analog of the displacement sensor. The welding current is controlled while comparing the displacement amount (lead wire penetration curve shown in FIG. 2). When the displacement amount stops, the welding is completed, and the current value is returned to 0 while supplying the cooling current. This will be repeated.

EFFECTS OF THE INVENTION As described above, according to the present invention, the welding current value is controlled while directly detecting the melted amount of the lead wire as an analog displacement amount. Therefore, the lead wire welding strength is irrespective of the state of the cut surface of the lead wire tip. While maintaining a stable state,
Since it does not supply excessive electric energy, it does not wear the wire chuck, fixed electrode, and movable electrode, and minimizes the amount of electric power to complete economical lead wire welding of resistors with excellent welding accuracy. it can.

[Brief description of drawings]

1 and 2 are timing charts of a lead wire welding method for a resistor according to an embodiment of the present invention, and FIG. 3 is a schematic view showing the construction of the same embodiment and a conventional welding machine, and FIG.
The figure is a timing chart of a conventional lead wire welding method for a resistor.

Claims (1)

[Claims] 1. When welding a lead wire to a resistor electrode, a DC constant current power source is used as a power source, and the amount of the lead wire melted is directly detected by a sensor as an analog displacement amount and stored in a computer in advance. A method for welding a lead wire of a resistor, comprising controlling a welding current value while comparing it with a welding target current curve.