JPH06333709A - Lead welder for cylindrical type resistor - Google Patents

Abstract

PURPOSE:To solve trouble, in which the diameter of a lead welded by a device for welding the lead to the terminal cap of a cylindrical type resistor body is increased in the resistor body side, in the device. CONSTITUTION:A lead welder for a cylindrical type resistor is constituted in such a manner that a pair of welding chucks 7a, 7b holding a lead 5 extending over specified length are moved forward in the axial direction of the lead and abutted against a terminal cap 3 in the lead 5 and welding is carried out by conducting electricity among the terminal cap 3 and the welding chucks 7a, 7b. Each welding chuck 7a, 7b can be opened and closed relatively, and is connected at or toward a holding application point 19 to the lead 5 respectively to a pair of support members 12a, 12b capable of being forward moved or retreated in the axial direction of the lead.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for welding a lead wire to a terminal cap of a cylindrical resistor.

[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 are fitted to both ends of a cylindrical element body 2 having a resistor film formed on its circumferential surface to form a resistor body 4, and the resistor body 4 is cut on the resistor film on the surface of the element body. After setting the resistance value, the lead wire 5 is welded to both terminal caps 3 of the resistor body 4. A protective exterior coating 6 is applied to the surface of the resistor body 4.

In the welding of the lead wire 5, as shown in FIG. 5, the lead wire is sandwiched by a pair of welding chucks 7 and 7, and as shown in FIG. The tip of is pressed against the terminal cap 3, and a large current is passed between the welding chuck 7 and the terminal cap 3 in that state. At this time, heat is generated in the contact portion between the terminal cap 3 and the lead wire 5 and the lead wire 5 is melted. As a result, the lead wire 5 and the terminal cap 3 are melted.
It is welded and joined.

[0004]

In this type of cylindrical resistor 1 having a basic form as shown in FIG. 4, both lead wires 5 are bent on the user side as shown in FIG. It is inserted and mounted on a predetermined circuit board.

By the way, it has been found that when the lead wire 5 is bent as described above, unevenness is conventionally observed in the bent portion. For example, as shown in FIG. 7, it has been found that a case where the bent portions of the left and right lead wires have different radiuses may occur. Such a variation in the bending process of the lead wire 5 causes a defect such as a mounting defect in the mounting process on the circuit board. In particular, recent automatic mounting devices have been accelerated in speed, and for this reason, the accuracy of the interval between the lead wires 5 and 5 extending from both ends of the resistor 1 and bent is more required.

Conventionally, such bent lead wires 5,
As a result of various studies on the cause of the non-uniformity of the intervals of No. 5, the following was found. That is, the radius of the bent portion is large like the lead wire on the right side of the cylindrical resistor 1 in FIG. 7 because the lead wire 5 is slightly thicker at that portion.

Since the wire diameter of the lead wire material is uniform at various points in the longitudinal direction, such an increase in the diameter of the lead wire occurs during welding to the resistor body.

That is, in the welding device, the lead wire 5
The reason is that the pair of welding chucks 7, 7 for sandwiching the part of the welding chuck 7 open with the front side open as shown in FIG. The pair of welding chucks 7, 7 is usually attached to a pair of supporting members that open and close relative to each other, but even if such attachment is surely made in the initial stage, the operation is repeated over a long period of time. It is considered that rattling occurs at the connecting portion between the welding chuck and the supporting member.

Further, it has been found that if the welding chucks 7, 7 are left in the front open state as shown in FIG. 6, the following problems will occur. That is, when the welding chucks 7, 7 are moved forward in the state of holding the lead wire to press the tip end portion of the lead wire 5 against the terminal cap 3 of the resistor main body, this is directly caused by the inclination of the welding chuck 7 itself. 3, the welding current flows in a short circuit between the welding chuck 7 and the terminal cap 3. A sufficient welding current does not flow through the lead wire 5, and as a result, defective welding may occur.

The present invention has been devised under the circumstances described above, and a welding current is caused to flow by pressing a lead wire sandwiched by a pair of welding chucks to the resistor body, and the resistor body of the lead wire is pressed. It is easy to avoid the occurrence of the front open state of the welding chuck over time, and to avoid the thickening of the lead wire after welding or the poor welding of the lead wire to the resistor body. The task is to achieve by the configuration.

[0011]

In order to solve the above problems, the present invention takes the following technical means. That is, the present invention provides a pair of welding chucks for holding a lead wire for a predetermined length with respect to the terminal cap in the main body of the cylindrical resistor in which the terminal caps are fitted to both ends of the cylindrical body. A lead wire welding device for a cylindrical resistor configured to be advanced by advancing in the axial direction of a lead wire so as to abut against the terminal cap, and weld by energizing between the terminal cap and the welding chuck, Each of the above welding chucks can move relative to each other,
It is characterized in that it is connected to a pair of support members that can move back and forth in the axial direction of the lead wire, respectively, at the clamping action point on the lead wire or at the front side thereof.

[0012]

The welding chuck according to the present invention is connected to the supporting member at the nipping point of the lead wire or at the front side of the nipping point. Therefore, the moment that the front side of each of the welding chucks is opened does not act on the welding chucks due to the reaction force when the pair of welding chucks clamps the lead wire by driving the supporting members so as to reduce the distance between them, or it is applied. Moments are significantly reduced.

Therefore, even if play or rattling occurs in the connecting portion between the welding chuck and the supporting member while the welding operation of the lead wire is repeated, a pair of lead wires are held when the lead wire is clamped. The front sides of the welding chucks do not open to each other, or the tendency thereof is remarkably reduced.

As a result, the conventional problem that the front side of the welding chuck is opened when the lead wire is clamped and the lead wire becomes thicker in the vicinity of the resistor body is eliminated or alleviated. When the lead wire is bent for mounting on the substrate, the bending quality is constant, and the distance between the pair of lead wires in the bent state is uniform. Further, even when a cylindrical resistor having a lead wire welded by the device of the present invention is mounted on a circuit board at a high speed, this can be performed without any inconvenience.

Furthermore, since the welding chuck is not tilted, it does not come into direct contact with the terminal cap, and a short circuit between the welding chuck and the terminal cap loses much of the welding current and the problem that welding strength is significantly reduced is solved. To be done.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below.
A specific description will be given with reference to the drawings.

The basic construction of the lead wire welding apparatus 10 for a cylindrical resistor of the present invention is the same as the conventional one. That is,
As shown in FIGS. 1 and 2, a pair of terminal caps 3 and 3 of the resistor body 4 are sequentially sent to a fixed position for lead wire welding by a transport holding mechanism 11 such as an indexing mechanism. Welding chucks 7a, 7
The front end of the lead wire 5 clamped by b is pressed, and in this state, a welding current is passed between the welding chucks 7a, 7b and the terminal cap 3, and the front end of the lead wire 5 is melted by this welding current. Is connected to the terminal cap 3.

Therefore, the welding chucks 7a and 7b are required to open and close each other and reciprocate in the axial direction of the resistor body 4.

The pair of welding chucks 7a and 7b are attached to the support base B or the support member 12 attached thereto. In the embodiment shown in the drawing, one support member 12a is fixedly or integrally provided with the support base B, and the other support member 12b swings about the shaft 13 with respect to the support base B. It is provided in. More specifically, the other support member 12b is
It is formed in an arm shape that swings around the shaft 13, and one of the welding chucks 7b is attached to this arm-shaped support member.

The swing arm-shaped support member 12b is swung by a cam drive mechanism or the like (not shown), and the welding both chucks 7a and 7b are closed as shown by the solid line in FIG. Both welding chucks 7a, 7
The open state of b can be selected.

Further, a support base B for supporting the support members 12a, 12b and the welding chucks 7a, 7b.
Are reciprocally driven in the axial direction of the resistor body 4 by a guide mechanism (not shown).

Each of the welding chucks 7a, 7b has a block shape with a rectangular cross section, and the opposing surfaces 14, 14 have
A chuck groove 15 having a cylindrical inner surface for holding the lead wire 5 in a fitting shape over a predetermined length is provided in an opposed shape. The rear sides of the facing surfaces of the two welding chucks 7a and 7b are guide surfaces 16 and 16 formed so that the distance between them gradually increases toward the rear, and lead wires sent from the rear side. 5 can be smoothly guided between the chuck grooves 15, 15.

A member of the transport holding mechanism 11 that contacts the terminal cap 3 and the welding chucks 7a,
A welding power source is provided between the switch 1 and the switch 7b.
By closing 8, the terminal cap 3
A welding current can be passed between the welding chucks 7a and 7b.

Now, in the present invention, the welding chucks 7a, 7b are supported by the support member 12 for supporting them.
The contact points a and 12b are connected to the lead wire 5 at the clamping action point or at the front side thereof. In the embodiment shown in the drawings, the chuck groove 15 having a cylindrical inner surface is formed over a length of about two-thirds on the front side of the facing surface of each of the welding chucks 7a and 7b. The substantially central portion in the direction can be regarded as the nipping action point 19.

In the present invention, the welding chucks 7a, 7b and the support members 12a, 12b for supporting them are connected at the clamping action point 19 or in front of the clamping action point 19 in the axial direction of the lead wire 5. Of. Each welding chuck 7a, 7b and supporting member 12a, 12
The connection with b can be made, for example, by a mounting screw 20.

The lead wire welding apparatus 10 having the above structure operates as follows. First, between the pair of welding chucks 7a and 7b in the open state at the resistor main body 4 held at a predetermined position or at the position where the resistor main body 4 is retracted with respect to the expected position to be conveyed. The lead wire 5 is sent out for a predetermined length, and the welding chucks 7a, 7b
Mutually close to clamp the front end portion of the lead wire 5. When the lead wire 5 is cut from its front end to a predetermined length, the support bases that support the welding chucks 7a and 7b or the entire support member that supports the welding chucks 7a and 7b move forward at a predetermined pressure,
The front end of the lead wire 5 is pressed against the surface of the terminal cap 3 of the resistor body 4. In this state, a welding current is passed between the terminal cap 3 and the welding chucks 7a and 7b for a certain time. Then, due to the resistance of the contact portion between the terminal cap 3 and the lead wire 5, the contact portion generates heat, and the tip portion of the lead wire 5 melts as shown in FIG.
Connected to. During this time, since the pressing force in the forward direction is continuously applied to the support base B, the tip melting portion of the lead wire 5 is shaped like a so-called nail head as shown in FIG. 3, and the terminal has a relatively large area. It will be welded to the cap 3.

When the above welding operation is completed, the welding chucks 7a and 7b are opened and the lead wire 5 is
Is retracted in the axial direction of. The resistor 1 to which the lead wire 5 is welded is carried out by the indexing rotation of the carrying and holding mechanism 11, and then the above-described welding operation is repeated.

Needless to say, the pair of lead wires 5 are welded to the terminal caps 3, 3 at both ends of the resistor body 4 in synchronization with each other on both sides of the resistor body 4 as described above.

By the way, in the present invention, as described above, the welding chucks 7a, 7b are connected to the support members 12a, 12b for supporting the welding chucks 7a, 7b at the clamping point 19 for the lead wire or in front of it. ing. Therefore, the support members 12a, 12 that move relative to each other are opened and closed.
The closing clamping force applied from b to each of the welding chucks 7a, 7b acts on the clamping action point 19 on the lead wire 5 or in front of it. Therefore, when the lead wire 5 is sandwiched by the welding chucks 7a and 7b, no moment is exerted on the respective welding chucks 7a and 7b to open their front end sides from each other, or such moment is significantly reduced. To be Therefore, if the welding chucks 7a, 7b and the support members 12a,
Even if rattling with time occurs in the connecting portion with 12b, the front end sides of both welding chucks 7a and 7b will not be opened unintentionally when the lead wire 5 is clamped. Or it is significantly reduced.

Therefore, as in the conventional case, while the welding operation is repeatedly performed for a long period of time, both welding chucks 7a, 7a are
It is almost impossible for b to open at the front end side thereof and the lead wire 5 becomes thicker near the resistor body due to this.

From the above, in the cylindrical resistor 1 in which the lead wire 5 is welded by the device of the present invention, when the lead wire is bent as shown in FIG. 7, uniformity of the bent form is ensured. The distance between the pair of bent lead wires is made constant. Therefore, when the lead wire is bent into the form shown in FIG.
It is possible to provide a resistor suitable for high-speed mounting in which the accuracy of lead wire spacing is strictly required.

Further, since the welding chucks 7a, 7b do not inadvertently incline as in the conventional example shown in FIGS. 5 and 6, the welding failure caused by the direct contact between the welding chucks 7a, 7b and the terminal cap 3. Will never happen.

Of course, the scope of the present invention is not limited to the above embodiments. Welding chucks 7a, 7
The specific shape of b, the mechanism for supporting and opening / closing these, and the like are not limited in any way.

Further, the connection of the welding chucks 7a and 7b to the support members 12a and 12b may be performed by one mounting screw as in the embodiment, or may be performed by a plurality of mounting screws. The problem is the welding chuck 7a, 7
If the welding chucks 7a and 7b are connected to the support members 12a and 12b at the clamping action point 19 of the lead wire 5 with respect to the lead wire 5 or in front thereof, even if the welding chucks 7a and 7b are connected to other portions. All are included in the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view of an embodiment of the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a partial cross-sectional side view showing an operating state of the embodiment shown in FIG.

FIG. 4 is a sectional view showing a general structure of a cylindrical resistor.

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

FIG. 6 is an operation explanatory view of a conventional example.

FIG. 7 is a side view of a cylindrical resistor in which a lead wire is bent and formed.

[Explanation of symbols]

 3 Terminal Cap 4 Resistor Body 5 Lead Wire 7a Welding Chuck 7b Welding Chuck 10 Lead Wire Welding Device 12a Supporting Member 12b Supporting Member 19 Clamping Point

Claims (1)

[Claims] 1. A pair of welding chucks for holding a lead wire with respect to the terminal cap in a main body of a cylindrical resistor having terminal caps fitted to both ends of a cylindrical element for a predetermined length. A lead wire welding device for a cylindrical resistor, which is configured to be advanced in the axial direction of a wire so as to abut against the terminal cap, and to weld by energizing between the terminal cap and the welding chuck. Each welding chuck is capable of relative opening and closing movement, and with respect to a pair of support members that can move back and forth in the axial direction of the lead wire,
A lead wire welding device for a cylindrical resistor, characterized in that they are connected to each other at a clamping action point on the lead wire or at a front side thereof.