JPS6348145B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the method of fixing an electrical terminal to the tip of the outer conductor of a tube-shaped light bulb.

Tube-shaped light bulbs, such as double-ended iodine bulbs and bromine bulbs, generally have an incandescent filament 2 stretched inside a quartz tube 1, and both ends of the incandescent filament 2 are attached to both ends of the quartz tube 1, as shown in FIG. Press seal part 3a,
While connecting to the metal foils 4a and 4b in 3b,
Electrical terminals 6a, 6b are fixed to the tips of outer conductive wires 5a, 5b, one end of which is connected to the metal foils 4a, 4b, and the other end of which protrudes from the press seal portions 3a, 3b. 7a and 7b are insulating covers fitted around the electrical terminals 6a and 6b. In addition, in such a structure, the outer conductors 5a and 5b are usually made of a high melting point metal such as molybdenum or tungsten, and the electric terminals 6a and 6b are made of a low melting point metal such as nickel. It is normal to have

By the way, in such a tube-shaped light bulb, the outer conductor 5
There have been various methods of fixing the electrical terminals 6a, 6b to the tips of the terminals a, 5b.
Typical examples thereof are shown in FIGS. 2 to 4.

In the device shown in FIG. 2, a tongue piece 8 is integrally formed at a suitable position on the back surface of the electric terminal 6, and the tip of the outer conductor 5 is welded to this tongue piece 8. However, in such a structure, if the tongue piece 8 is formed at the center of the back of the electrical terminal 6, the electrical terminal 6
When fixed to the outer conductor 5, the center of the electrical terminal 6 is shifted from the center line X-X' of the outer conductor 5 and the incandescent filament as shown in the figure. Also,
Even if the tongue piece 8 is formed at a position offset from the center of the back surface of the electrical terminal 6 in order to eliminate this drawback, it is difficult to set the position, and even if it can be set accurately, the outer conductor 5 may not be on the center line. Otherwise, the same problem as above will occur.

This drawback becomes a fatal defect when the tube-shaped light bulb is used in applications where the socket and reflector must be placed in precise positions, for example, when used in optical equipment such as copying machines.

Figure 3 shows that in order to eliminate the above-mentioned defects, a cylindrical protrusion 9 is formed at the center of the back of the electrical terminal 6, and the tip of the outer conductor 5 is inserted into this part and welded or soldered. It is something. According to this structure, since the center of the electric terminal 6 coincides with the outer conductor 5, there is an advantage that the electric terminal 6 will not deviate from the center line if the outer conductor 5 is in an accurate position. However, if the position of the outer conductor 5 is shifted, the second
A similar problem arises to the structure shown in the figure. In addition, in both this structure and the structure shown in FIG. 2, the cylindrical protrusion or tongue piece is intentionally formed on the back surface of the electrical terminal 6, which requires time and effort to process the electrical terminal, resulting in high material costs. It has the disadvantage of becoming

FIG. 4 shows an example of a structure in which no tongue piece or protrusion is provided on the back surface of the electrical terminal. A through hole 10 is provided in the center of the electrical terminal 6, and the tip of the outer conductor 5 is inserted into the through hole 10. It was inserted and soldered. but,
With such a structure, it is difficult to obtain a good finish because the tip of the outer conductor protrudes through the through hole 10 to the contact recess of the electrical terminal 6 during assembly, and the solder leaks out.

FIGS. 5 and 6 illustrate an example of the most preferred method of securing electrical terminals, although this has not been practiced to date.

That is, the electrical terminal 6 is directly fixed to the tip of the outer conductor 5 by butt welding. With this structure, even if the outer conductor 5 is in the normal position as shown in FIG.
The electrical terminal 6 can always be placed and fixed on the center line X-X' of the incandescent filament even if it is in a deviated position. Furthermore, there is no need to form a tongue protrusion on the back surface of the electrical terminal 6 or to provide a through hole in the electrical terminal.

However, until now, it has been difficult to actually adopt the structure shown in FIGS. 5 and 6.
The reason for this is that when attempting to butt weld an outer conductor made of a high-melting point metal and an electrical terminal made of a low-melting point metal, the temperature of the outer conductor rises to an extreme level due to the difference in heat capacity caused by the materials and volumes of the two. This is because the internal structure of the metal changes from a fine fiber structure to coarse crystals and becomes brittle, making it impossible to obtain the required mechanical strength.

For this reason, as a method of butt welding an electric terminal to an outer conductor, as shown in FIG. Measures such as butt welding the tip of the terminal 11 to the electrical terminal 6 have been adopted (Japanese Patent Laid-Open No. 55-91561).

However, since this method uses a hollow connecting rod 11, it not only requires a large number of parts, resulting in high cost, but also has the disadvantage that it requires a lot of effort to assemble.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a practical method for directly fixing an electric terminal to the tip of the outer conductor of a tube-shaped light bulb by butt welding.

To carry out the present invention, first, as shown in FIG.
At the same time, the electric terminal 6 is set in the movable holder 13 located at a position facing the tip of the outer conductor 5.

The embedding length l of the outer conductive wire 5 into the electrical terminal 6 is usually approximately 0.3 to 0.6 mm. Further, the set position of the electric terminal 6 with respect to the tip of the outer conductor 5 can be appropriately stabilized by slightly moving the movable holder 13 in the horizontal direction.

Next, as shown in FIG. 9, the movable holder 13 is pushed up to bring the electric terminal 6 into contact with the tip of the outer conductor 5, and while a welding current is passed between them, the electric terminal 6 is attached at a weight of 2 to 7 kg. Press it against the tip of the outer conductor 5 with a pressure of . Then, the portion of the electrical terminal 6 that is in contact with the outer conductor 5 melts, and the tip of the outer conductor 5 is almost completely embedded in this portion.

Then, the power is turned off and the welded part is removed from the device.

Note that resistance welding or arc welding may be used to perform the above-mentioned butt welding, but in any case, it is desirable to apply a constant current or constant electric power to the welded portion in order to stabilize the welding. In the examples, resistance welding was used and the welding current was controlled within the range of 300 to 600 amperes.

FIG. 10 shows a fixed portion of an electrical terminal assembled by the method described above. The tip of the outer conductor 5 is completely embedded in the back surface of the electrical terminal 6, and the mechanical strength of this portion is extremely high.

The reason why the above effects can be obtained in the present invention is as follows.

In other words, during butt welding, the tip of the outer conductor is made to protrude from the outer conductor holder by only the embedding length into the electrical terminal, and the protruding part is almost completely embedded in the electrical terminal, so that the tip of the outer conductor is not added to the outer conductor during welding. Heat and heat accumulated in electrical terminals mainly escape through the outer conductor holder.
It is possible to prevent the temperature of the outer conductor from rising rapidly, and therefore it is possible to prevent the welded portion from becoming brittle. Furthermore, since the length of the external conductor embedded in the electrical terminal is constant, there is also the advantage that the total length of the tube-shaped light bulb can be made constant. Furthermore, this method has the advantage that it can be easily assembled automatically by a machine and is suitable for mass production of raw products.

The optimal implementation values of the present invention are as follows.

A Outer conductor material Molybdenum Outer conductor diameter 0.6 to 0.8 mm C Electrical terminal material Nickel or copper-nickel alloy E Outer conductor protrusion length 0.3 to 0.6 mm E Butt pressure 2 to 7 kg F Resistance welding current 300 to 600 A Based on the above explanation As is clear, in the present invention, the tip of the outer conductor of a tube-shaped light bulb is set in the outer conductor holder with the tip protruding by the length of embedding into the electric terminal, and then the electric terminal is brought into contact with the tip and the distance between the two is set. The electrical terminal is weighed between 2 and 7 kg while applying welding current to
The electric terminal is directly fixed to the tip of the outer conductor by pressing it against the tip of the outer conductor with a pressure of The most desirable structure as shown in FIG. 6 and FIG. 6 can be put into practical use.

[Brief explanation of the drawing]

Fig. 1 is a side view of a tube-shaped light bulb, Figs. 2 to 4 and 7 are side views of conventional electrical terminal fixing parts, and Figs. 5 and 6 are side views of the most desirable electrical terminal fixing part. , FIG. 8 and FIG. 9 are explanatory diagrams of the assembly work when carrying out the present invention, and FIG. 10 is a sectional view of the electric terminal fixing part assembled according to the present invention.

Claims (1)

[Claims] 1. After setting the tip of the outer conductor of the tube-shaped light bulb into the outer conductor holder with the tip protruding by the embedded length relative to the electric terminal, an electric terminal made of a low-melting point metal is brought into contact with the tip of the outer conductor, and then these An electrical terminal is attached to the tip of the outer conductor by pressing the electric terminal against the tip of the outer conductor with a pressure of 2 to 7 kg while applying a welding current to embed the tip of the outer conductor almost completely in the electric terminal. A method for fixing electrical terminals of tube-shaped light bulbs, which is characterized by direct fixation.