JPS6056345A - Coil filament for bulb - Google Patents

Abstract

PURPOSE:To obtain a coil filament which does not result in missing of core wire and tangle of filament by holding a core wire through compression of fine lead at the end portion of a secondary coil. CONSTITUTION:A fine lead 3 consisting of a high melting point metal such as W is wound with an interval around a core lead 1 consisting of a high melting point metal such as W to form the primary coil 4 and further it is wound to form a secondary coil. The fine lead 3 is partly flatened at the several turns in both ends 51 of said secondary coil 5 and these flatened portions hold the core lead 1 from both sides. Therefore, the end portion 51 of secondary coil 5 is compressed and thereby the external diameter becomes small. Thereby, the core lead is not removed and tangle of filament can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a coil filament for a tube that prevents the core wire made of a high-melting point metal such as tungsten from coming off and entangling the filaments with each other due to this phenomenon.

[Technical background of the invention]

A coil filament for a tube, for example a coil filament for a fluorescent lamp, is made of a core wire made of a high melting point metal such as tungsten, attached to a primary mandrel, and surrounded by a core wire made of a high melting point metal. 4! +l wire is wound to form a transmission coil,
This secondary coil A is wound around a secondary mantle to form a secondary coil, which is then cut to a desired length and then removed by melting both mandrels.

The filament obtained in this manner remains as a gap after the L-order mandrel is removed, and the core wire extends in a floating state in the -order coil.

Such filaments have advantages over ordinary coiled filaments, such as being able to hold more electron-emitting materials and being relatively easy to manufacture, and are rapidly becoming popular.

[Problems with background technology]

Because the core wire is in a floating state, vibrations during manufacturing or transportation may cause the core wire to pull out several turns from the transmission coil, which causes the filaments to become entangled with each other, which causes problems in tube manufacturing. The downside is that the workability of folding decreases with age.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a coil filament for a tube without the risk of core wires falling out or entanglement of filaments with each other.

[Summary of the invention]

The thin wire is crushed at the end of the secondary coil to sandwich the core wire, thereby fixing the core wire inside the transmission coil.

[Embodiments of the invention]

The details of the present invention will be explained by way of examples. This example shows an example of a coil filament for a fluorescent lamp to which the present invention is applied. Among them, (1) is a core wire made of a high melting point metal such as tungsten, (3) is a thin wire made of a high melting point metal such as tungsten wound around this core wire (1) with a gap, and (4) is a core wire made of a high melting point metal such as tungsten. The transmission coil (5) is formed by winding the thin wire (3), and the secondary coil (5) is formed by further winding the secondary coil (4).

The feature of this filament is that the thin wire (3) is locally crushed in several turns at both ends I5D of the secondary coil (5), as shown in enlarged views of the main parts in Figures 3 to 5. This crushed part C31) and C3υ become the core wire (
1) is sandwiched from both sides. As a result, the end portion 61) of the secondary coil (5) is compressed and has a smaller outer diameter.

To manufacture this filament, as shown in FIG. (r
This secondary coil (4) is then connected to the secondary mandrel (6).
to form a secondary coil (5). This secondary coil (5) is cut (8), (8). By this crushing, the thin wire (3) is strongly pressed between the punch (7) and the secondary mandrel (6) and is crimped onto the core wire (1). Then,
The thin wire (3) is locally crushed and flattened, and is sandwiched between the core wires (11) from both sides. In this state, it becomes permanently deformed and the core wire (1) is fixed. Soak to chemically dissolve and remove Mandre, Q12+, (6).

However, as mentioned above, the thin wire (3) is crushed and flattened [7] and is sandwiched between the core wires, so the -order mandrel (21
(removed) Also later, the pressure field parts 6υ and Qll are stuck to the core wire (1) due to permanent distortion, and the vibration 71! It will not leave due to h etc. Therefore, the core wire (1) is -
The filaments do not have to be pulled out from the next coil (41), and the filaments do not get entangled with each other due to the coil (1).

Finally, go to the top C] 8 drums of filament deformation by crushing and li of the core wire (1)! +I investigated the correlation with the eyebrow effect, 5
As a result, if the core wire (1) is not crushed properly, the core wire (1) is not fully solidified and easily comes off when shaken.On the other hand, if the core wire (1) is crushed too much, cracks or dents occur in the thin wire (3). There is a drawback that the disconnected parts become entangled.

Therefore, we created a mathematical formula for the appropriate amount of crushing.

The diameter of the tungsten core wire (1) is dliil-The diameter of the mandrel (2)'i-d2rs
) is the diameter of d31ffl.The outer diameter of the secondary coil (5) is D
If the outer diameter of the secondary coil (5) after crushing is dm, then D-
d shows a deformed sweet due to crushing. Also, −order mandrel (
The diameter of 2) can be calculated empirically from the filament dimensions using the conversion formula described below.

According to experiments, when the following formula holds true, the core wire (1)
Good adhesion of 5 and no cracks or breaks in thin m(3).

ds+ (dz d+)≦1)−d≦2d.

Next, the formula for calculating the diameter of the -order mandrel (2) is shown below.

d2-=(i4(lL+2dx)) where d4 is the major diameter of the transmission coil Next, the incidence of entanglement was actually measured for the following various coil filaments.The specifications of the filaments are shown in the following table.

(Left below) In general, in order for such a coil filament to retain a large amount of electron radioactive material, it is better to
Moreover, they are almost a mesh of coiled filaments for fluorescent lamps for general lighting, and once d and d2 are determined, other dimensions are determined automatically in most cases.

At the same time, the trial filaments shown in the above table were crushed under various amounts of deformation, and the incidence of entanglement of the filaments at that time was investigated, and the results are shown in FIGS. 8 to 12.

In both of these figures, the horizontal axis shows the deformation r, +CDct) in units of cod, and the vertical axis shows the entanglement incidence in units of chi. Filament No. 2, Figure 10 is filament No. 3, No. 11
The figure shows the correlation for the 4 Mi filament, and Figure 12 shows the correlation for the No. 5 filament.

As is clear from these figures, regardless of the dimensions of the filament, the deformation j (D-d) is ds +
It can be seen that if the diameter is smaller than (dt d+), tangles occur frequently due to core wire pull-outs, and if it is larger than 2d, tangles occur frequently due to cracks or breaks in the thin wire. fact,
(D - d ) ) 2 d 2 (t(,') There was a probability of 80 cracks in the thin wire.

In addition, in the present invention, the above-described structure can be obtained even if, for example, a bench is inserted into the secondary coil and a part of the coil at several turns at the end is crushed. The part to be crushed may be only a part of the coil on one side of the secondary coil. Furthermore, the portion to be crushed may be a few turns at the end of the T-order coil, which can be crushed by 3 to 3 turns. It's a shame, the core wire and thin wire could be made of molybdenum.

〔Effect of the invention〕

The coil filament for tubes of the present invention is formed by winding a thin high-melting point metal wire around a high-melting point metal core wire through a gap, and further winding a part of the coil to form a secondary coil. Since the thin wire is crushed at the end of the wire to sandwich the core wire, the core wire will not be pulled out, and there will be no entanglement of the filaments with each other due to this.

[Brief explanation of drawings]

FIG. 1 is a front view of one embodiment of the coiled filament for a tube according to the present invention, FIG. 2 is a partially enlarged front view, FIG. 3 is an explanatory cross-sectional view of the end, and FIG. 4 is a thick section. FIG. 5 is an enlarged front view, FIG. 5 is a sectional view of the portion shown in FIG. 4, FIGS. 6 and 7 are explanatory diagrams explaining the manufacturing method step by step, and FIGS. It is a graph which determines the appropriate value of the amount of deformation due to crushing. (1)... Core wire (2+...- next mandrel (3+...
...Thin wire (4)...-Secondary coil (5+...Secondary coil (6)...-Secondary-endrel 6υ...Crushed part A Fig. 1 Fig. 2 Fig. 4 Fig. 5 Interval 6 Figure 7 Figure 8 Figure 9 - (D-d) mnt ” (D-cl)/l?/le 1st
Figure 0 ■ Eye distance-“D-d) mm

Claims (2)

[Claims] (1) A transmission coil formed by winding a fine high melting point metal wire around a high melting point metal core wire through a gap is further wound to form a secondary coil, and the end portion of the secondary coil is A coil filament for a sphere, characterized in that the a+ wire is crushed and pinches the core wire. (2) The diameter of the tungsten core wire is +11, the diameter of the −order mandrel is d2, and the diameter of the tungsten thin wire is f.
:(fs, the outer diameter of the secondary coil is D, and the crushed outer diameter of the secondary coil is d, then a3+(d, d
The coil filament for a tube according to claim 1, characterized in that the following relationship holds true: +)<,D-d(2d.