JP2003282004A - Manufacturing method of annular fluorescent lamp - Google Patents

Abstract

(57) [Problem] To manufacture a ring-shaped fluorescent lamp in which the strength of the side and bottom portions is prevented and the stable quality is obtained by synchronizing the pressing of the constricted portion forming member and the pressing of the concave portion forming member. Provide a way. SOLUTION: A lower end of a vertically held glass tube 1 is fused to form a closed end portion 10, and a constricted portion molding member is formed on a side surface near the closed end portion while the vicinity of the closed end portion 10 is in a softened state. 1
1 while pressing the recess forming member 13 against the bottom surface of the closed end, simultaneously forming the constricted portion 16 on the side surface near the closed end and the concave portion 17 on the bottom surface of the closed end. The glass tube 1 is sandwiched and wound up to form an annular glass tube. Since the pressing of the constricted portion forming member 11 and the pressing of the concave portion forming member 13 are synchronized with each other, the constricted portion can be formed while pushing the bottom upward, and the thickness of the constricted portion can be increased while the thickness of the bottom is made uniform. The prevention of thinning can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an annular fluorescent lamp for illumination, and more particularly to a method for manufacturing an annular fluorescent lamp in which annular glass tubes having different annular diameters are connected to each other to form a compact high output lamp.

[0002]

2. Description of the Related Art Conventionally, two types of annular glass tubes having different ring diameters are connected in a state of being arranged on the same plane or on two planes separated from each other to form a single discharge path, which has a small size and a high output. Double annular fluorescent lamps are known.

In the structure disclosed in, for example, JP-A-8-124525 and JP-A-8-236074, two annular glass tubes having different ring diameters are arranged on the same plane and on the same circle center. . And a stem with an electrode is sealed at one end of the glass tube, and a stem without an electrode is sealed at the other end,
One discharge path is formed by connecting the vicinity of the end portion where the stem without electrodes is sealed with a bridge.

FIG. 5 is a diagram showing an example of a conventional glass tube cyclization step. The straight glass tube 40 has the constricted portion 4 with the sealing portion side of the stem 41 with electrodes facing upward.
2 is sandwiched by the sandwiching member 43 and held vertically.
The glass tube 40 is softened by heating, and the lower end portion where the electrodeless stem 44 is sealed is supported by the receiving member 45. In this state, the constricted portion 47 near the lower end is held by the holding head 46 and rolled up to form an annular glass tube.

[0005]

However, the above-mentioned conventional method for manufacturing a double annular fluorescent lamp has the following problems. (1) The method of sealing the stem without an electrode at one end of the glass tube has an advantage that the sealing device used at the other end for sealing the stem with an electrode can be diverted, but the stem itself is required, so that the material cost is high. Was getting higher. (2) In the softened state due to heating, the glass tube hangs under its own weight, the deviation of the glass wall thickness becomes large in the vicinity of the sealing portion of the electrodeless stem 44, and distortion occurs, or the constricted portion 47.
When the glass thickness of No. 2 becomes thin, the constricted portion 47 may be peeled off during winding up by the holding head 46, making it impossible to wind up. (3) As shown in FIG. 5, due to the presence of the supporting thin tube 48 of the electrode-less stem 44, the receiving member 45 cannot be securely fitted into the recess 49, and the constricted portion 47 is displaced from the normal position. In some cases, the constricted portion 47 cannot be clamped by the clamping head 46. (4) Variation in flare diameter of the electrode-less stem 44,
If there is a partial crack at the peripheral edge of the flare, the strength of the sealing portion may be reduced, and the sealing portion may be cracked or the constricted portion may be peeled off at the time of winding. (5) As shown in FIG. 6, according to the method of closing the lower end of the glass tube 50 into a substantially flat shape or a substantially curved shape that bulges outward, there is no stem in the closed portion, so the above problem occurs. Disappears. However, in this case, when the glass tube 50 is heated and softened, the tube end portion 54 hangs by its own weight, but the contact position between the tube end portion 54 and the receiving member 56 deviates from the normal position, and the glass The pipe 50 may be tilted, and the pipe shaft 51 and the shaft 57 of the receiving member 56 may be displaced. In this case, since the position of the constricted portion 52 also shifts, it may not be possible to accurately perform the clamping by the clamping member 55. (6) According to the method of closing the lower end of the glass tube in a substantially flat shape or in a substantially curved shape which bulges outward without using a stem in the closing portion, the variation in the glass wall thickness in the vicinity of the tube end during the closing process is In some cases, the size of the glass tube becomes large and distortion occurs in the closed portion and the narrowed portion, peeling of the narrowed portion occurs when the glass tube is rolled up, and cracks occur in the closed portion when moving various processes or when the finished product is turned on.

The present invention solves the above-mentioned conventional problems, and prevents the strength reduction of the side surface portion and the bottom portion by synchronizing the pressing of the constricted part molding member and the pressing of the recessed part molding member. It is an object of the present invention to provide a method for manufacturing an annular fluorescent lamp that can obtain stable quality.

[0007]

In order to achieve the above-mentioned object, a method of manufacturing an annular fluorescent lamp according to the present invention is to hold a straight glass tube in a vertical direction and to fuse and close the lower end of the glass tube. While forming the end portion, while the vicinity of the closed end portion is in a softened state, while pressing the constricted portion molding member to the side surface near the closed end portion, press the concave portion molding member to the bottom surface of the closed end portion. And forming a constriction on the side surface near the closed end and a recess on the bottom surface of the closed end at the same time, sandwiching the constriction, and rolling up the glass tube to form an annular glass tube. .

According to the method for manufacturing the annular glass tube as described above, the pressing of the constricted part molding member and the pressing of the recessed part molding member are synchronized, so that the constricted part is formed while pushing the bottom part upward. You can Therefore, it is possible to prevent the necked portion from being thinned while making the bottom portion uniform in thickness. As a result, it is possible to prevent residual strain on the side surface portion and the bottom portion, to prevent a decrease in strength, and to increase the clamping strength of the constricted portion, while at the same time ensuring the strength to withstand impact.

In the method of manufacturing the annular fluorescent lamp, it is preferable that the closed end is formed by heating and melting the vicinity of the lower end of the glass tube and then removing the excess cullet. According to the method for manufacturing an annular glass tube as described above, the closed end can be formed more easily and reliably than in the case where the opening is directly closed.

Further, when the glass tube is rolled up, the concave portion is once supported by a receiving member having a convex portion corresponding to the concave portion, and the constricted portion has a clamping member having a convex portion corresponding to the constricted portion. It is preferable to release the support by the receiving member after sandwiching with. According to the method for manufacturing an annular glass tube as described above, since the recessed portion of the glass tube bottom is accurately and reliably supported by the receiving member, it is possible to prevent the inclination of the glass tube with respect to the tube axis, and to easily hold the constricted portion. It will be reliable, the glass tube winding work will be smooth,
Distortion of the annular glass tube after winding can also be prevented.

Further, it is preferable that two annular glass tubes having different ring diameters are arranged concentrically, and the vicinity of the constricted portion of each glass tube is bridge-connected to each other to form one discharge path. According to the method for manufacturing an annular glass tube as described above, when heating the connecting portion of the bridge, the temperature rises in the vicinity of the constricted portion, but in the vicinity of the constricted portion, the glass wall thickness is relatively uniform and the strength is high. Is also stable, so
Strain generation due to temperature rise will be suppressed. As a result, it is possible to prevent damage to the tube end portion in the vicinity of the constricted portion both during the manufacturing process and when lighting the finished product.

Further, it is preferable that the constricted portion molding member is formed of a plurality of members obtained by dividing an annular member having a projection formed along the inner periphery thereof. According to the method for manufacturing an annular glass tube as described above, it is possible to simultaneously open and close a plurality of annular members, so that the constricted portion can be formed efficiently and accurately.

Further, it is preferable that the recess molding member is provided with a substantially frustoconical projection. According to the method for manufacturing an annular glass tube as described above, the glass tube can be stably and reliably supported.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A method for manufacturing a double annular fluorescent lamp according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a process diagram of a method for manufacturing an annular fluorescent lamp according to this embodiment.

FIG. 1A shows an open end 6 at the lower end of the glass tube 1.
The state before the blockage on the side is shown. At the top of the glass tube 1,
The stem 3 with the electrode 2 is sealed. Glass tube 1
A constricted portion 4 is formed on the outer periphery of the upper end of the concavity 4, the outer peripheral surface of which is recessed in the circumferential direction. The holding body 5 holds the constricted portion 4, and vertically supports the glass tube 1 with the open end 6 facing downward. Reference numeral 18 is a lead wire, and 19 is an exhaust thin tube. The opening end 6 side is closed by heating and softening the planned closing portion 7 with a gas burner 8 as a heating means.

FIG. 1B shows a state after the opening end 6 side is closed. In the state of this figure, the excess cullet 9 has been removed, and the scheduled closing portion 7 is fused and the closed end portion 10 is removed.
Are formed. The closed end portion 10 is provided with a reservoir having an increased thickness of the glass material. As described above, since one end of the glass tube 1 forms the closed end portion 10 without sealing the stem, the stem itself becomes unnecessary,
It is possible to improve productivity and reduce costs. Further, according to the method of removing the excess cullet 9 and forming the closed end portion 10, the closed end portion 10 can be formed more easily and more reliably than the method of directly closing the opening. This method is an effective method when the closed end is formed while the glass tube 1 is vertically supported as in the present embodiment.

FIG. 1C shows a step of forming a constricted portion and a concave portion at the lower end of the glass tube 1. The neck is
In the subsequent annularizing process of the glass tube 1, the glass tube 1 is a portion for sandwiching the glass tube 1, and the recess is a portion for supporting the glass tube 1. While the vicinity of the closed end 10 of the glass tube 1 maintains the softened state, the constriction molding member 11 is pressed against the side surface of the glass tube 1 near the closed end 10, while the recess molding member is formed on the bottom surface 12. 13 is pressed and pressed. That is, the pressing of the molding member 11 and the pressing of the molding member 13 are synchronized.

Here, the constricted portion molding member 1 is shown in FIG.
1 shows an enlarged perspective view of one embodiment, and FIG. 2B shows an enlarged perspective view of one embodiment of the recess molding member 13. Figure 2
The constricted portion molding member 11 shown in FIG.
A protrusion 15 for constriction molding is formed along the inner circumference of the divided semi-annular members 11a and 11b.

By using the constricted portion molding member 11 as described above, the constricted portion 16 in which the outer circumference of the glass tube 1 is depressed in the circumferential direction can be formed so that the shape thereof does not vary. Moreover, since the pair of semi-annular members 11a and 11b are used, simultaneous opening and closing are possible, and the constricted portion can be efficiently and accurately molded.

The recess molding member 13 shown in FIG.
Since the shape of the protrusion 14 is a substantially truncated cone shape with good releasability,
The shape of the recess 17 can be formed accurately and accurately.

By thus forming the constricted portion 16 and the recessed portion 17, the constriction of the constricted portion 16 and the support of the recessed portion 17 become safe and reliable in the subsequent annularizing step.

FIG. 1D shows a state after pressing by the molding members 11 and 13. The constricted portion 16 is formed at the lower end of the glass tube 1 by the pressing force of each molding member 11, 13.
Thus, the recess 17 is formed at the same time.

Since the pressing of the molding member 11 and the pressing of the molding member 13 are synchronized with each other, the constricted portion 16 is formed while pushing the bottom portion upward. For this reason,
It is possible to form the constricted portion 16 before the progress of thinning of the side surface portion due to its own weight while dispersing and equalizing the thickness of the bottom portion where the meat reservoir is formed. That is, it is possible to prevent the thinning of the constricted portion 16 while making the thickness of the bottom portion uniform.

As a result, it is possible to prevent residual strain on the side and bottom portions, and also to prevent the strength from decreasing. Therefore, in the process of annularizing the glass tube 1, peeling-off and loss of the constricted portion 16 can be prevented, and the constricted portion 16 can be prevented. It is possible to increase the clamping strength when clamping the. Further, it is possible to prevent the occurrence of cracks or damages on the tube end of the glass tube during transportation in the manufacturing process or during lighting of the finished product. Further, in this cyclization step, the glass tube 1 hangs down slightly due to its own weight and is supported by the receiving member of the concave portion 17, but it is possible to secure sufficient strength to withstand the impact at this time.

On the other hand, when the pressing by the molding member 11 and the pressing by the molding member 13 are separately performed without synchronizing the molding member 11 and the molding member 13, the thickness of both the side surface portion and the concave portion is In some cases, the thickness may be reduced, the thicknesses of both sides may be extremely varied, or the constricted portion 16 or the recessed portion 17 may be finished in an irregular shape, so that a predetermined shape cannot be obtained. In this case, the constricted portion 16 and the recessed portion 17 cannot serve as a pinch or a support.

FIG. 3 is a diagram for explaining the step of circularizing the glass tube 1. The annularizing step is a step of forming the tubular glass tube 1 having the constricted portion 16 and the recessed portion 17 into an annular shape by a winding means through the steps of FIG. First, FIG.
As shown in (a), the glass tube 1 is held by the holding body 5.
It is vertically supported with the recess 17 facing downward. After this, the temperature at which the glass tube 1 can be rolled (about 660-6
Heat to 80 ° C.) to soften.

The softening of the glass tube 1 causes the glass tube 1 to hang downward due to its own weight. The concave portion 17 is once supported by the receiving member 20 in a state where the hanging amount of the lower end of the glass tube 1 is h (about 30 to 40 mm). Next, the constricted portion 16 is held by the holding head 21 which is a pair of semi-annular members.

FIG. 3 (b) schematically shows a state in which the recess 17 is supported by the receiving member 20 and the constricted portion 16 is sandwiched by the sandwiching head 21. From this state, the receiving member 2
The support of the concave portion 17 by 0 is released, that is, the receiving member 20 is moved in the arrow direction, and the glass tube 1 is rolled up. In the winding step, the glass tube 1 is wound around a roller jig and the glass tube 1 is circularized while the holding head 21 holds the necked portion 16.

Here, the concave portion 16 is previously provided with the receiving member 2
Since it is formed into a shape that fits into 0, the receiving member 20
With the concave portion 17 supported by, the inclination of the glass tube 1 with respect to the regular position can be prevented, and the accuracy of fitting the holding head 21 and the constricted portion 16 can be improved. As a result, the work of circularizing the glass tube 1 proceeds smoothly, and it is possible to suppress the generation of defective products due to the deformation of the glass tube 1 or the inability to be rolled up.

FIG. 4 shows a plan view of a double annular fluorescent lamp according to an embodiment of the present invention. The double annular fluorescent lamp 25 shown in this figure is formed by arranging two annular glass tubes 22 and 23 having different annular diameters concentrically and in the same plane. Each annular glass tube 2
2 and 23 are formed through the steps as shown in FIGS. The annular glass tube 22 and the annular glass tube 23 are connected by a bridge 24 in the vicinity of the constricted portion 16, and one discharge path is formed.

When connecting the bridge 24, the connecting portion is heated by a heating means such as a gas burner, and the temperature in the vicinity of the constricted portion 16 rises. However, in the vicinity of the constricted portion 16 formed through the above-described steps, the glass thickness is relatively uniform and the strength is stable, so that the strain generation due to the temperature rise can be suppressed. As a result, it is possible to prevent damage in the vicinity of the constricted portion 16 including the pipe end portion during transportation of the manufacturing process and during lighting of the finished product.

The arrangement of the annular glass tubes is not limited to the example shown in the figure. For example, the planes formed by the two annular glass tubes may be separated from each other, and set appropriately according to the user's light distribution performance requirements. do it.

Hereinafter, the present invention will be described in more detail by explaining the experimental results. The glass tube used for the experiment is shown in FIG.
This is a glass tube used for manufacturing the double annular fluorescent lamp 25 as shown in FIG. The outer diameter of the two long and short glass tubes is 2
When the double ring fluorescent lamp is completed, the ring outer diameter is 400 mm, the ring inner diameter is 314 mm, and the rated power is 97 W.

The experiment was conducted for three kinds of manufacturing methods.
In each manufacturing method, the lower end of the vertically supported glass tube was sealed and closed, and the glass tube was circularized.
Two annular glass tubes are connected via a bridge to manufacture a double annular fluorescent lamp having one discharge path.

The first embodiment is a manufacturing method as shown in FIGS. 1 to 3, in which a concave portion molding member 13 and a constricted portion molding member 11 are formed.
And the constricted part and the recessed part were formed. Comparative Example 1
Forms a constricted part using the constricted part molding member 11,
No recess was formed by the recess molding member 13. Also,
In Example 1 and Comparative Example 1, the stem was not sealed at the lower end of the glass tube.

Comparative Example 2 is a manufacturing method in which the lower end of the glass tube is sealed with a stem without an electrode and then the constricted portion is formed by using the constricted portion molding member 11. The concave portion formed by the concave portion molding member 13 is not formed. . The electrode-less stem used in Comparative Example 2 has the same structure as the electrode-equipped stem for a double ring fluorescent lamp with a rated power of 97 W, and has a structure in which no electrode is attached to the lead wire, and the exhaust pipe is closed to prevent the stem flare. Tear off,
Moreover, the lead wire was also cut in the stem flare and used for sealing.

In each experiment, the constricted portion molding member 11 was shared. As the constricted portion molding member 11, a pair of semi-annular member molds made of stainless steel which is a heat-resistant material is used, and the inner peripheral surface of each semi-annular member has a height of 2.5 mm and a width of 3 mm.
A protrusion with a rounded tip is formed.

Further, the recess forming member 13 used in the first embodiment.
Was a mold made of stainless steel which is a heat-resistant material, having a truncated cone-shaped projection having a short diameter of 2 mm, a long diameter of 8 mm, and a height of 10 mm.

The setting conditions and the experimental results are summarized in Table 1 below.

[0040]

[Table 1]

In Comparative Example 1, after the excess cullet was removed, when the constricted part molding member was pressed against the side surface of the glass tube, the lower end of the glass tube, which was the free end, was slightly inclined, and A constricted part was formed which was inclined with respect to. For this reason, there occurs a defect that it is impossible to hold the constricted portion before winding.

In Comparative Example 1, since the recess molding member 13 was not used, the bottom of the softened glass tube drooped slightly due to its own weight, and some roundedness was formed on the bottom of the glass tube. It was In this case, although the glass tube bottom part is in contact with the supporting member for the glass tube bottom part in an inclined manner and the constricted part is formed in a regular shape, there is also a problem that the constricted part cannot be clamped by the constricted part clamping head. did.

In Comparative Example 2, distortion occurred due to the thickness deviation between the sealed portion at the end of the glass tube and the constricted portion in the vicinity thereof. As a result, the strength of the constricted portion was lowered, and the constricted portion peeled off during winding, resulting in unwinding. Further, in Comparative Example 2, since the bottom of the glass tube is sealed by the stem, as shown in FIG. 5, there is the remaining supporting thin tube 48 in the recess 49, so that the receiving member 45 ensures the recess of the stem. There is also a problem in that the glass tube cannot be fitted in 49, the position of the constricted portion 47 and the position of the constricted portion clamping head 46 are displaced, and it becomes impossible to clamp the glass tube for winding. Further, since the stem is used, the strength of the sealing portion is lowered due to the presence of variations in the flare diameter of the stem and the lack of the flare peripheral edge, which causes problems such as cracks and peeling off of the necked portion during winding.

In contrast to Comparative Examples 1 and 2, in Example 1, the wall thickness deviation between the closed portion at the lower end of the glass tube and the constricted portion in the vicinity thereof was small, and no strain was generated. For this reason,
No peeling off of the constricted portion at the time of winding, cracking of the closed portion, and the like, the nipping of the constricted portion by the nipping head was also reliable, and the problems as occurred in Comparative Examples 1 and 2 did not occur.

Further, in Example 1, the glass wall thickness of the bottom portion due to the closing of the lower end of the glass tube is equalized by the pressing of the recess molding member, and no distortion occurs, so that there is no impact when it is supported by the receiving member. Even so, no inconvenience such as breakage occurred.

Further, when an experiment was carried out in which the pressing by the constricted part molding member and the pressing by the recessed part molding member were preceded by each other, the time in the heat-softened state was prolonged, and the constricted part and the concavity part were recessed. Was not suitable for practical use because of the irregular shape, deformation, and variation in wall thickness.

The manufacturing method according to the present invention is not limited to the setting of the processing conditions, dimensions, materials, shapes, types, etc. described in each of the above-mentioned embodiments and examples, and may be arbitrarily set. .

[0048]

As described above, according to the present invention, since the pressing of the constricted portion molding member and the pressing of the recessed portion molding member are synchronized, the constricted portion can be formed while pushing the bottom portion upward. it can. Therefore, it is possible to prevent the necked portion from being thinned while making the bottom portion uniform in thickness. As a result, it is possible to prevent residual strain on the side surface and the bottom, prevent a decrease in strength, and increase the clamping strength of the necked portion,
It is possible to secure sufficient strength to withstand impact.

[Brief description of drawings]

FIG. 1 is a process diagram of a method for manufacturing an annular fluorescent lamp according to an embodiment of the present invention.

FIG. 2A is a perspective view of a constricted portion molding member according to an embodiment of the present invention. FIG. 2B is a perspective view of a recessed molding member according to an embodiment of the present invention.

FIG. 3 is a process diagram of processes up to setting for circularization according to an embodiment of the present invention.

FIG. 4 is a plan view of a double annular fluorescent lamp according to an embodiment of the present invention.

FIG. 5 is a diagram showing an example of a conventional glass tube cyclization step.

FIG. 6 is a view showing another example of a conventional glass tube cyclization step.

[Explanation of symbols]

1 glass tube 2 electrodes 3 stems 4,16 constriction 10 closed end 11 Constricted part molding 11a semi-annular member 13 Support recessed parts 14, 15 protrusions 17 recess 20 Receiving member 21 clamping head 24 bridge 25 double ring fluorescent lamp

Claims (6)

[Claims] 1. A straight glass tube is held vertically, a lower end of the glass tube is fused to form a closed end, and the closed end is in a softened state near the closed end. While pressing the constricted part molding member on the side face in the vicinity, pressing the recessed part molding member on the bottom surface of the closed end, the constricted part on the side surface near the closed end part and the recessed part on the bottom surface of the closed end part at the same time. A method for manufacturing an annular fluorescent lamp, which comprises forming the annular tube by sandwiching the constricted portion and rolling up the glass tube. 2. The method for manufacturing an annular fluorescent lamp according to claim 1, wherein the closed end is formed by heating and melting the vicinity of the lower end of the glass tube and then removing the excess cullet. 3. When the glass tube is rolled up, the concave portion is temporarily supported by a receiving member having a convex portion corresponding to the concave portion, and the constricted portion is provided with a clamping member having a convex portion corresponding to the constricted portion. The method for manufacturing an annular fluorescent lamp according to claim 1 or 2, which is carried out after the support member is released after being clamped by. 4. The two glass tubes having different ring diameters are arranged concentrically, and the vicinity of the constricted portion of each glass tube is connected to each other by a bridge to form one discharge path. 4. The method for manufacturing an annular fluorescent lamp according to any one of 3 to 3. 5. The annular fluorescent lamp according to claim 1, wherein the constricted portion molding member is formed of a plurality of members obtained by dividing an annular member having a protrusion formed along an inner circumference thereof. Production method. 6. The method for manufacturing an annular fluorescent lamp according to claim 1, wherein the recess molding member includes a substantially frustoconical projection.