JP2906015B2 - Apparatus and method for welding lead wire of cylindrical resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for welding a lead wire to a terminal cap of a cylindrical resistor. The present invention relates to a stable lead wire even when an AC power supply is used to apply a welding current. To improve the welding strength of the steel.

[0002]

2. Description of the Related Art A cylindrical resistor 1 as shown in FIG. 4 is manufactured through the following steps. Terminal caps 3 and 3 made of a conductive metal are fitted to both ends of a cylindrical body 2 having a resistor film formed on the peripheral surface to form a resistor body 4. After setting the resistance value by, for example, applying spiral cutting to the resistor film on the surface, the lead wire 5 is connected to the terminal cap 3 of the resistor body 4.
Are welded. Then, a protective coating 6 is applied to the surface of the resistor main body 4.

[0005] As shown in FIG. 5, the lead wire 5 is welded by a pair of welding chucks 7, 7.
And the welding chucks 7, 7 are advanced to press the lead wire 5 against the center of the terminal cap 3, and in this state, a predetermined welding current is applied between the welding chucks 7, 7 and the terminal cap 3 for a predetermined time. Shed. At this time, heat is generated in this portion due to the resistance of the contact surface (welding surface) between the terminal cap 3 and the lead wire 5, the tip of the lead wire 5 melts into the terminal cap 3, and the two are welded.

[0004]

In the meantime, for welding the lead wire 5 to the terminal cap 3 as described above, conventionally, it has been usual to use an AC power supply as it is and to apply a welding current. Then, the voltage of the welding current flowing between the lead wire 5 and the terminal cap 3 has a sine waveform as shown in FIG. In general, it is known that when the above-described alternating current flows through a conductor, the current tends to flow in a region limited to an annular shape in a cross section of an outer periphery of the conductor or a vicinity thereof. Conventional lead wire 5 described above
Also in welding the terminal cap 3 and the terminal cap 3, the AC welding current tends to flow unevenly in the outer periphery of the lead wire 5 or in a region limited to an annular shape in the vicinity thereof, and as a result, the following problems occur. .

First, if the voltage of the welding current is slightly higher than the optimum voltage, the penetration at the welding surface between the lead wire 5 and the terminal cap 3 becomes annular and penetrates the terminal cap 3. As shown in FIGS. 5 and 6, the lead wire immediately after welding comes off with a slight external force in such a manner that a hole is formed in the terminal cap 3.

Second, if the voltage of the welding current is set lower than the optimum voltage in order to avoid the first problem, the welding at the center of the welding surface is not performed correctly, and the terminal The welding strength to the cap 3 is insufficient.

As described above, when a welding current having an AC waveform is applied between the lead wire 5 and the terminal cap 3 using the conventional AC power supply as it is, it is extremely difficult to set the optimum voltage. If the optimum voltage is not set properly, a large amount of lead wire welding defects will occur.

As a third problem, since a large current flows in a deviated cross-sectional area near the outer periphery of the lead wire 5,
As shown in FIG. 5, the tips of the welding chucks 7, 7 may be severely worn, and the life of the welding chuck may be shortened. Solder peeled off from the surface of the lead wire easily adheres to the worn portion, and causes slippage with the welding chuck when the lead wire is pressed against the terminal cap. Then, the pressing force of the lead wire 5 against the terminal cap 3 becomes insufficient, which also leads to poor welding.

The present invention has been conceived in view of the above circumstances, and is intended for welding a lead wire to a terminal cap of a cylindrical resistor by applying a welding current using an AC power supply. Even so, heat is generated as evenly as possible over the entire welding surface between the lead wire and the terminal cap, so that the width of the optimum voltage of the welding current can be increased and stable welding strength can be obtained. The challenge is to do so.

[0010]

Means for Solving the Problems To solve the above problems, the present invention takes the following technical means. That is, the invention described in claim 1 of the present application is an apparatus for welding a lead wire to the terminal cap in a cylindrical resistor body in which terminal caps are fitted to both ends of a cylindrical element. ,

A support for supporting the resistor body, a welding chuck for holding the lead wire and pressing the tip of the lead wire to a terminal cap of the resistor body, a welding chuck and the terminal at a predetermined timing; A power supply device for supplying a welding current between the caps, the power supply device outputting only an AC power supply and a quarter wavelength or less portion sandwiching each positive or negative vertex of a voltage waveform of the AC power supply; And a control unit that performs the control.

According to a second aspect of the present invention, there is provided a method for welding a lead wire to a terminal cap of a cylindrical resistor body in which terminal caps are fitted to both ends of a cylindrical body. When a welding current is applied between the lead wires in a state where the tips of the lead wires are pressed against the terminal cap, the welding current sandwiches each positive or negative vertex of the voltage waveform of the AC power supply. 1/4
It is characterized in that only the portion below the wavelength is used.

[0013]

According to the present invention, the voltage waveform of the AC power supply is not directly applied as the welding current, but the positive or negative peak of the voltage waveform is sandwiched.
Only the portion of / 4 wavelength or less is given as the welding current.
Therefore, the welding current flowing between the lead wire and the terminal cap has DC characteristics, and the problem of applying a welding current having an AC waveform is eliminated or reduced. In particular, in the present invention, as described above, only the portion having a wavelength of 以下 wavelength or less is given as the welding current. Because of this, the degree of improvement of the problem in the case where the welding current having the AC waveform is applied is further improved.

That is, in the present invention, the welding current is given by using the AC power supply, but the welding current actually flowing between the lead wire and the terminal cap has a characteristic of DC or close to DC. Therefore, the welding current does not flow to the outer periphery of the lead wire or the annular region near the lead wire, and the equalized welding current flows to the entire welding surface between the lead wire and the terminal cap. Therefore, the first and second problems described in the section of the prior art are solved, and stable welding strength between the lead wire and the terminal cap can be obtained.

Further, even if the welding current flows at a voltage higher than the predetermined voltage, the penetration of the lead wire does not penetrate through the terminal cap as in the prior art, and as a result, the width of the appropriate voltage is reduced. Is expanded more than before. This means that an appropriate voltage can be set much more easily than in the past, and that stable welding strength can be obtained.

Furthermore, since the penetration of the lead wire into the terminal cap can be averaged over the entire welding surface, welding defects do not occur even if the terminal cap is made thinner as compared with the prior art. The cost of the terminal cap material can be reduced.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.
This will be specifically described with reference to FIGS. As shown in FIG. 4, the resistance is set by fitting the terminal caps 3 and 3 to both ends of the cylindrical element body 2 and setting the resistance value by cutting the resistor film on the element body surface. The container body 4 has both ends, that is, both terminal caps 3, 3
Is supported on a support 8 to weld the lead wire 5 to the center of the outer end face in the axial direction. For example, the supporting body 8 may adopt a form in which holding grooves 9 are provided at equal intervals on the outer periphery of a disk-shaped member having a predetermined thickness which is rotated by indexing about a horizontal axis. The resistor main body 4 mounted in each holding groove 9 via a feeder (not shown) at a suitable portion on the rear side in the rotation direction of the support 8 is carried to the welding position as the support 8 rotates.

Welding chucks 7, 7 are arranged on both sides in the axial direction of the resistor main body 4 which has been carried to the welding position by the support member 8 rotating by indexing. In FIGS. 1 and 2, Only the right welding chucks 7, 7 are shown. A pair of the welding chucks 7 is supported by a welding head (not shown) so as to be openable and closable with each other. Further, the welding head supporting the welding chucks 7, 7 moves forward and backward.

When the welding head is in the retracted position and the welding chucks 7, 7 are moving toward each other, a lead wire material 5 is introduced between the welding chucks 7, 7 in the horizontal direction for a predetermined length. Then, the welding chucks 7, 7 close each other to pinch the lead wire material 5, and at the rear of the welding chucks 7, 7, the cutter 10 cuts the lead wire material from the tip to a predetermined length. At this time, the tip of the lead wire 5 is protruded from the tip of the welding chuck 7, 7 by a certain length (FIG. 1).

Next, the welding head advances and presses the lead wire 5 clamped by the welding chucks 7 against the center of the outer surface of the terminal cap 3 of the resistor body 4 on the support 8 with a predetermined pressure. At that timing, a predetermined welding current flows between the terminal cap 3 and the lead wire 5 (FIG. 2).

The welding chucks 7 and 7 are formed of a conductor, and a portion of the support 8 where the terminal cap 3 comes into contact is also formed of a conductor. Between the wirings 11, 11
The power supply device 12 is provided via the power supply device. In the present invention, the power supply device 12 includes an AC power supply 13 and a control unit 14.

In the present invention, the AC power supply 13
A lamp power supply of 0 or 60 Hz and a frequency of the lamp power supply of, for example, 15 Hz using an AC / AC inverter, for example.
This is a concept that includes any of the power sources obtained by changing the above.

The control means 14 is a phase control means including, for example, an SCR, and outputs only a partial wavelength of the voltage sine waveform generated by the AC power supply 13 sandwiching the positive or negative peak. As illustrated in FIG. 3, the control unit 14 cuts out and outputs a 部分 wavelength (a portion indicated by a solid line) sandwiching the positive vertex 0 from the sine waveform. In order to enjoy the advantage of the direct current of the welding current output or a characteristic close to the direct current in the present invention, as described above, one of the sinusoidal waveforms that sandwiches the apex is used.
It is preferable to cut out and output a wavelength of / 4 or less.

As described above, when the lead wire 5 is pressed against the terminal cap 3, the control means 1
When the welding current controlled by 4 flows between the lead wire 5 and the terminal cap 3, heat is generated due to the resistance of the contact portion (welding surface) between the lead wire 5 and the terminal cap 3,
The lead wires 5 are melted into the terminal cap 3 and the lead wires 5 and the terminal cap 3 are welded. Although the present invention uses an AC power supply as the power supply, FIG.
Since only the waveform portion indicated by the solid line, that is, only the portion of 1/4 wavelength or less sandwiching the peak of the sine waveform is actually output as the welding current, this welding current has a small peak value variation, DC or DC. It has similar characteristics.

Therefore, the welding current flows uniformly across the cross section of the lead wire, and the penetration of the lead wire into the terminal cap is also uniformed over the entire welding surface as shown in FIG.

When the above welding is completed, the two welding chucks 7, 7 are opened to release the pinching of the welded lead wire, and then the welding head is retracted and the support 8 is opened.
Rotates by one pitch for indexing, and carries the next resistor body 4 to the welding position. Hereinafter, by repeating the above-described operation, the welding of the lead wire 5 to the resistor body 4 that is successively carried to the welding position on the support 8 is continuously performed.

As described above, according to the present invention,
Lead wire 5 on terminal cap 3, 3 of cylindrical resistor body 4
When welding is performed, a welding current having substantially the characteristics of direct current can be flowed between the lead wire 5 and the terminal caps 3 and 3 despite the use of an AC power supply.
Therefore, various problems in the case of using an alternating current as a welding current are solved, the welding strength of the lead wire 5 is stabilized, the width of an appropriate voltage is extended, and the wear of the welding chuck is suppressed to extend the life. Can be achieved.

Further, at the time of welding, it is possible to suppress a problem in which the lead wire 5 melts into the terminal cap 3 unevenly on the welding surface and penetrates through the terminal cap 3. As a result, the material cost of the terminal cap can be reduced.

Of course, the present invention is not limited to the embodiment described above. The specific configuration of the support for supporting the resistor body and the welding head including the welding chuck is not limited at all.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is an operation explanatory view of one embodiment of the present invention.

FIG. 3 is a waveform diagram of a welding current in the present invention.

FIG. 4 is a partial cross-sectional side view showing a general configuration of a cylindrical resistor.

FIG. 5 is an explanatory diagram of a conventional example.

FIG. 6 is an explanatory diagram of a conventional example.

FIG. 7 is a waveform diagram of a conventional welding current.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical resistor 4 Resistor main body 5 Lead wire 7 Welding chuck 8 Support body 12 Power supply device 13 AC power supply 14 Control means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01C 17/28 H01G 13/00 B23K 11/00

Claims (2)

(57) [Claims] An apparatus for welding a lead wire to a terminal cap of a cylindrical resistor body in which terminal caps are fitted to both ends of a cylindrical element body, the apparatus supporting the resistor body. A support, a welding chuck that clamps the lead wire and presses the tip of the lead wire to a terminal cap of the resistor main body, and a power supply that supplies a welding current between the welding chuck and the terminal cap at a predetermined timing. The power supply device comprises: an AC power supply; and a control unit configured to output a quarter wavelength or less portion sandwiching each positive or negative vertex of the voltage waveform of the AC power supply. A lead wire welding device for a cylindrical resistor, characterized in that it is formed to include. 2. A method for welding a lead wire to said terminal cap in a cylindrical resistor body in which terminal caps are fitted to both ends of a cylindrical element body, said method comprising: When a welding current is passed between these while the tip of the lead wire is pressed,
The method for welding a lead wire of a cylindrical resistor, wherein the welding current uses only a portion having a quarter wavelength or less sandwiching each positive or negative vertex of the voltage waveform of the AC power supply.