JPH0818141B2 - Butt welding method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a butt welding method, and more specifically,
For example, when trying to resistance-weld a similar linear second work to a linear first work having an insulating coating, a predetermined range of the first work is chucked in advance, and then, The first work is energized and heated under the action of Joule heat while applying a pressing force from the axial direction of the first work, thereby bulging and forming the portion other than the chucked portion to remove the insulating coating. It is intended to perform butt resistance welding between linear works by passing an electric current between the bulging part where the coating is removed and the second work, and thereby the production efficiency is high and the work is good. The present invention relates to a butt welding method which is excellent in its external shape even after welding and is suitable for use between works having different heat balances.

BACKGROUND OF THE INVENTION Conventionally, for example, in a cathode ray tube, a plurality of lead wires are exposed to the outside of the cathode ray tube to hermetically shut off the inside from the outside and supply a predetermined amount of current from the outside. That is, as shown in FIG. 1, the cathode ray tube has a large face plate portion 2 and a deflection coil portion 4.
And a neck portion 6. A grid 8, a first plate 10, a second plate 14, a focus plate 16 and the like are sealed in the neck portion 6, and a predetermined current is supplied to the deflection coil portion 4 to deflect the beam direction. Is configured to form an image inside.

On the grid 8 side of the neck portion 6, usually, a plurality of lead-in wires 18 are exposed to the outside and fitted into a socket (not shown) (see FIG. 2). This is to supply a predetermined current from the outside to the deflection coil unit 4 and the like. In this case, the lead-in wire 18 is made of glass 20 that insulates the outside from the inside of the neck portion 6 and plastically deforms to maintain airtightness.
Are carried. FIG. 3 illustrates a preferable structure of the introduction line 18. That is, the lead-in wire 18 is the first
Lead wire 30, Dumet wire 32 and the first lead wire
Similar to 30, the second lead wire 34 is made of nickel.

In fact, as you can easily see from the figure, the first lead wire
30, the dumet wire 32, and the second lead wire 34 are welded so as to extend coaxially with each other, and the long lead-in wire 18 is formed as a whole. Dumet wire 32, as shown in FIG.
The central part is generally made of steel 35, and its periphery is covered with copper 36 of several microns.
36 is covered with boron 38 which is an insulator. Here, the use of boron 38 is that the wettability with the glass 20 carrying the introduction line 18 is good and that the boron 38 has substantially the same coefficient of thermal expansion as the glass, so the introduction line to the glass 20 is used.
This is because, when carrying 18, no gap is formed between the glass 20 and the Dumet wire 32 after cooling with the glass 20, and there is an advantage of being highly airtight. Therefore, FIG. 5 shows the basic structure of the apparatus for welding the linear works coaxially with each other. That is, the Dumet wire 32 is
As described above, since the outer peripheral portion is covered with the insulating coating boron 38, the first lead wire 30 and the dumet wire 32 are coaxially butted to obtain an electrical contact state. That is, several micron of copper 36 or steel 35 exposed from both ends of the dumet wire 32 is transferred to the first lead wire 30.
Contact. In this case, the first lead wire 30 is connected to the electrodes 40a, 4
It is sandwiched by 0b, while the Dumet wire 32 is pressed by the electrode 42 in the arrow direction. Therefore, the electrode 40
When a current is passed between the electrodes a and 40b and the electrode 42, this welding current flows in the direction of the arrow, and Joule heat is generated at the joint between the first lead wire 30 and the Dumet wire 32 to perform resistance welding.

However, even if a welding current is applied in the above-described configuration, it is difficult to satisfy the welding strength because the first lead wire 30 and the Dumet wire 32 are particularly thin wires. Moreover, since the welding current is passed through the dumet wire 32, the dumet wire 32 itself is heated, and there is an inconvenience of melting the boron 38 covering the outer peripheral portion thereof. Further, by heating the Dumet wire 32 in this manner, the outer shape is also deformed. That is, a thermal deformation state is induced.

As a result, the insulating film required for the Dumet wire 32 is destroyed, and when the glass is apt to be airtightly supported by being inserted into the portion of the glass 20 due to thermal deformation and dust, the glass is not supported. It has the drawbacks of poor matching, poor strength, and difficulty in ensuring airtightness.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned inconvenience, and previously chucks the body portion of the Dumet wire over a wide range with a chucking member, and then both ends of the Dumet wire. Current is applied while pressing the electrode from the portion, and the insulating film such as boron coated on the Dumet wire is peeled off by bulging a portion of the Dumet wire other than the chucking portion by heat generated by the applied pressure and electricity. , Then, another work such as nickel is coaxially joined to the Dumet wire, and the Joule heat is applied between the Dumet wire and the work by energizing the bulging part from which the insulating coating is removed and this work. It is an object of the present invention to provide a butt welding method, which is characterized in that the Dumet wire and the work are welded by this.

[Means for Achieving the Purpose] In order to achieve the above-mentioned object, the present invention uses a chuck member to chuck a predetermined range excluding the end portion of a linear first work having an insulating coating on its peripheral surface. By squeezing and pressing the first work from at least one side and energizing between the end parts, a bulging part from which the insulating film is removed is formed in a part other than the chucked part. A linear second workpiece is coaxially contacted with the bulging portion side of the workpiece, and electric current is applied between the chuck member and the second workpiece through the bulging portion so that the first workpiece and the second workpiece It is characterized by welding the workpiece.

[Embodiment] Next, a preferred embodiment of the butt welding method according to the present invention will be given and described in detail below with reference to FIG.

Generally, the Dumet wire 50 has a diameter of about 0.5 mm. Therefore, the Dumet wire 50 is sandwiched by the first electrode 52 and the second electrode 54 made of copper over substantially the entire length thereof. At that time, the coil spring 56 is attached to the first electrode 52, while the second electrode 54 is placed on the support 58. Therefore, when the Dumet wire 50 is sandwiched between the first electrode 52 and the second electrode 54, the first electrode 52 is pressed by the coil spring 56, so that the Dumet wire 50 moves toward the second electrode 54 side. It will be pressed through the electrode 52. Although not shown in the figure, at that time, the first electrode 52 and the second electrode 54 respectively sandwich the dumet wire 50 via the outer peripheral portion thereof,
It is preferable to define a recess for receiving the Dumet wire 50 in the electrode tip. Thus, the first electrode 52
After sandwiching the dumet wire 50 between the second electrode 54 and the second electrode 54, the third electrode 60 and the fourth electrode 62 are further brought into contact with both ends of the dumet wire 50.

Also in this case, like the first electrode 52, the coil spring 64 is provided at the tail end of the third electrode 60, and the coil spring 66 is provided at the tail end of the fourth electrode 62. . Therefore, the third electrode 60 and the fourth electrode 62 press the Dumet wire 50 from its axial direction. In such a state, a predetermined current is passed between the third electrode 60 and the fourth electrode 62. As a result, the Dumet wire 50 generates heat and is pressed in the direction of the arrow under the action of the coil springs 64 and 66. Therefore, as shown in FIG. 7, the portion not sandwiched by the first electrode 52 and the second electrode 54. That is, bulged portions 70a and 70b are formed at both ends of the Dumet wire 50. The formation of the bulged portions 70a and 70b means that the boron, which is an insulating coating of several microns covering the outer peripheral portion of the Dumet wire 50, is peeled off.

Therefore, from the bulged portions 70a and 70b, copper and steel portions of several microns shown in FIG. 4 are exposed to the outside. At that time, the bulging portions 70a and 70b are connected to the first electrode 52,
To the extent that the second electrode 54 and a part thereof contact each other, the third electrode 6
0, it is preferable to press the fourth electrode 62 (see FIG. 7).

In this way, the bulging portions 70a and 70b are connected to the Dumet wire 50.
Then, the first lead wire 72 made of nickel is coaxially contacted with the Dumet wire 50. Then, the first lead wire 72 is sandwiched between the fifth electrode 74 and the sixth electrode 76. Also at this time, like the first electrode 52, a coil spring 78 is attached to the tail end portion of the fifth electrode 74, and this is pressed toward the sixth electrode 76 side. Furthermore, the first lead wire 72 is pressed by the coil spring 80 toward the Dumet wire 50. In such a state, the fifth electrode 74 and the sixth electrode
A predetermined welding current is passed between 76 and the first electrode 52 and the second electrode 54.

In this case, the fifth electrode 74 and the sixth electrode 76 can be displaced in the Dumet wire 50 direction under the pressing action of the coil spring 80. As a result, the Joule heat generated between the first lead wire 72 and the bulging portion of the Dumet wire 50 melts them to obtain a joined state. Then, as described above, the fifth electrode 7
4. Since the sixth electrode 76 is displaced in the Dumet wire 50 direction, this pressing force is not released until the bulging portions 70a, 70b. In this case, the first electrode 52 and the second electrode 54 cause welding current to flow from the bulging portions 70a and 70b to the first lead wire 72 side, so that resistance welding is performed here.

Next, the second lead wire 82 is again joined to the bulged portion 70b side by the same method as described above. As a result, the lead-in wire in which the Dumet wire and the nickel wire are joined as shown in FIG. 9 is obtained.

[Effects of the Invention] As described above, according to the present invention, when it is attempted to resistance-weld a linear work, such as a Dumet wire, whose outer peripheral portion is provided with an insulating coating, and another linear work, With respect to the linear work on which the insulating coating is applied, chucking is performed in advance over a predetermined range, and then the insulating coating is removed by applying a pressing force from the axial direction while energizing, A bump-shaped bulge to secure heat balance is formed, and then the electrode is contacted by using this bulge from which the insulating coating is removed, and another linear work is brought into contact with this Dumet wire. Then, resistance welding is performed between the two by energizing them.

As a result, welding is performed over a wide area between the bulging portion of the Dumet wire and the first lead wire, and further, the bulging portion and the first lead from which the insulating coating has been removed in advance. Since the current-carrying action is performed between the wire and the wire, the current-carrying region is expanded, and the Dumet wire itself cannot be heated to a considerable temperature. Therefore, it is possible to avoid that the insulating coating, that is, boron, which is covered by the outer peripheral portion is not melted and the linear work is thermally deformed.

Therefore, the introduction line obtained in this way is, for example,
Even when it is attached to a vacuum tube, a Braun tube, or the like, it has good wettability with the glass portion carrying it, and it is possible to ensure airtightness and obtain an aesthetically pleasing lead wire.

Although the present invention has been described above with reference to the preferred embodiment, the present invention is not limited to this embodiment, and is not limited to a Dumet wire, for example, a linear work provided with another insulating coating. Similarly, resistance welding can be performed, and when forming the bulging portion, chucking can be performed by using a dedicated jig instead of the electrode. It is needless to say that various improvements and design changes can be made without departing from the gist of the present invention, for example, pressurization by another elastic member or an actuator such as a cylinder is possible instead.

[Brief description of drawings]

FIG. 1 is an explanatory view of a longitudinal section of a cathode ray tube using an introduction line, FIG. 2 is an explanatory view of a longitudinal section of a neck portion of the cathode ray tube shown in FIG. 1, FIG. 3 is a plan view of an ideal introduction line, and FIG. Fig. 3 is a vertical cross-sectional view of the lead-in wire shown in Fig. 3, Fig. 5 is a schematic explanatory view of an apparatus according to the prior art for resistance welding a lead wire made of nickel and a dumet wire constituting the lead-in wire, and Fig. 6 is a book FIG. 7 is an explanatory view showing a basic structure of an apparatus for carrying out the method of the invention, FIG. 7 is an explanatory view showing a state where a bulging portion is formed with respect to the Dumet wire after being chucked, and FIG. 8 is a bulging portion being formed. Fig. 9 is a basic explanatory view showing a state in which the first lead wire made of a nickel wire is joined to the formed Dumet wire, and Fig. 9 is a plan view showing a state in which the Dumet wire and another work are joined using the method of the present invention. is there. 50 …… Dumet wire, 52, 54, 60, 62 …… Electrodes 70a, 70b …… Swelling part, 72 …… Lead wire 74, 76 …… Electrode, 82 …… Lead wire

Claims (2)

[Claims] 1. A chucking member chucks a predetermined range excluding an end portion of a linear first work having an insulating coating on its peripheral surface, and presses the first work from at least one of the end portions. A bulging portion from which the insulating coating has been removed is formed on a portion other than the chucked portion by energizing the second portion, and the linear second work is coaxially provided on the bulging portion side of the first work. Abutting against, and energizing through the bulging portion between the chuck member and the second work,
A butt welding method comprising welding the first work and the second work. 2. The butt welding method according to claim 1, wherein the second work is welded by being pressed and displaced relative to the first work while being energized.