JP3565795B2 - Method and apparatus for producing flare for tube - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing a tube flare used for a fluorescent lamp, a high-pressure discharge lamp, a light bulb and the like.
[0002]
[Prior art]
Conventionally, as a method of manufacturing a tube flare, for example, a method using a heating means for a cylindrical valve and a first frame mold and a second frame mold for forming a flare is disclosed in JP-A-2000-215806. It is described in. In this manufacturing method, a cylindrical valve is disposed vertically on the lower first frame that is driven to rotate, and the upper side of the rotating valve is heated and softened by one burner, while the first valve is heated and softened. The flare is formed in a shape substantially equivalent to the flare shape of the frame, and finally the second frame is brought into contact with the valve from above to form a flare.
[0003]
[Problems to be solved by the invention]
However, in the above-mentioned conventional manufacturing method, although the valve is rotating, the end opening of the valve protruding from the first frame mold is pushed open by the heat of the burner at the same position, and the first frame is opened. Since it is formed in the flare shape of the mold, the expanded end opening is tapered, and when it fits in the tapered portion of the flare shape of the first frame mold, the excess glass tube thick portion is compressed. As a result, the tapered portion and the opening end become a fillet shape, and the final molding of the flare opening end portion by the second frame mold causes a strong compressive strain in the fillet, and when sealing with the tube container, There was a problem of causing a flare crack.
[0004]
In addition, when heating a valve with a burner, the heating direction and position of one burner are changed for each head position where the valve moves, so that it is possible to adjust the heating power at each position and feel the stability of the valve softening position. In addition, there is also a problem in that variations such as roundness of the shape of the opening end of the flare, dimensional accuracy, and deviation of the thickness at each flare portion occur.
[0005]
In addition, when the rotation of the valve is slow, the expansion of the opening of the valve can rely only on the thermal power of one burner. However, the position of one burner per head as the flare molding progresses. Variations in dimensions, shapes, distortions, and the like of the flare opening due to the difference in the direction occur, and there is also a problem of supplying an unstable quality flare at the time of sealing with the tube container.
[0006]
An object of the present invention is to solve the above-mentioned conventional problems and to obtain a flare having a stable performance without any abnormal shape, poor dimensional accuracy, uneven thickness, variation in distortion, and the like. That is, the present invention provides a manufacturing method and a manufacturing apparatus capable of reducing variations in the shape, dimensional accuracy, and the like of a flare opening or a tapered portion at the time of flare manufacturing, and preventing uneven thickness, thickening, and distortion.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a method for producing a tube flare according to the present invention comprises disposing a glass tube support pin slidable up and down on a shaft core tube portion of a rotatable flare forming die, A glass tube is placed in a forming die while being supported by the glass tube support pins, and the vicinity of the upper end of the glass tube is heated by a plurality of burners, and then engaged with the flare forming die to form a flare opening edge. A method of manufacturing a tube flare by pressing a pressing mold having a convex portion on a heated portion of the glass tube,
The glass tube, the glass tube support pin and the flare forming mold are heated by the burner while rotating, and the glass tube support is formed from the start of heating by the burner to the formation of a flare opening edge in the glass tube. The pin is lowered a plurality of times stepwise.
[0008]
As a result, it is possible to prevent flare in the vicinity of the tapered portion and the opening edge of the flare, so that the quality such as dimensional accuracy and glass strength is good, and a flare having a stable shape without uneven thickness and variation in distortion can be obtained. it can.
[0009]
In the manufacturing method of the present invention, it is preferable that the plurality of burners are arranged so as to heat at least two of an upper end surface, an outer wall surface near the upper side, and an inner wall surface of the glass tube.
[0010]
Thereby, the softening position of the glass tube at the time of flare formation becomes uniform, and a flare with few abnormal shapes and stable dimensional accuracy and shape can be obtained.
[0011]
Further, in the manufacturing method of the present invention, it is preferable that the pressing die has a protruding portion at a tip of the protruding portion. As a result, the uneven thickness of the glass in the tapered portion does not occur during flare formation, so that it is possible to manufacture a flare with less cracks and scratches, and since the opening of the flare and the cylindrical portion are coaxial, the flare shape is stabilized, The dimensional accuracy is also improved.
[0012]
In the manufacturing method of the present invention, it is preferable that the glass tube, the glass tube support pin, and the flare forming mold are rotated at 1000 RPM or more.
[0013]
As a result, the heated glass tube is spread in a flared funnel shape by centrifugal force. That is, at the time of flare formation, a stable performance and shape flare can be obtained by the synergistic effect of the opening widening action by the high-speed rotation centrifugal force of the glass tube and the appropriate heating action of the plurality of burners.
[0014]
Next, the tube flare manufacturing apparatus of the present invention is a rotatable flare forming mold in which a glass tube support pin slidable up and down is arranged on the shaft core tube portion,
A pressing mold having a convex portion capable of forming a flare opening edge by engaging with the mold ;
A plurality of burners for heating the glass tube near the upper end,
The method further comprises: the glass tube support pin that descends stepwise a plurality of times from the start of heating by the burner to the formation of a flare opening edge in the glass tube .
[0015]
As a result, it is possible to prevent flare from forming near the tapered portion and the edge of the opening, and to stabilize the quality, glass strength, and flare shape.
[0016]
Further, in the manufacturing apparatus of the present invention, it is preferable that the plurality of burners are arranged so as to heat at least two surfaces of an upper end surface, an outer wall surface near the upper side, and an inner wall surface of the glass tube.
[0017]
Thereby, the softening position of the glass tube at the time of flare formation becomes uniform, and various characteristics of the flare are stabilized.
[0018]
Further, in the manufacturing apparatus of the present invention, it is preferable that the glass tube supporting pin and the flare forming die include a unit that rotates at 1000 RPM or more.
[0019]
Thereby, when forming the flare, the synergistic effect of the opening widening action of the glass tube by the high-speed rotational centrifugal force and the appropriate heating action of the plurality of burners is exhibited, so that the performance and shape of the flare are stabilized.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
1 to 9 are process diagrams showing one example of a method for producing a tube flare of the present invention.
[0022]
In the step a shown in FIG. 1, 1 is a glass tube for flare, 2 is a glass tube supporting pin which vertically supports the glass tube 1 and is slidable up and down. Are arranged in combination with the shaft core tube portion of the flare forming mold 3. After the annealing step (FIG. 8) and the flare removal step (FIG. 9) after the flare formation in the previous step are completed, the flare forming mold 3 and the glass tube supporting pin 2 which have been heated to some extent are subjected to the process b ( In FIG. 2), a glass tube 1 having a predetermined length is vertically inserted and supported. When the glass tube 1 is inserted, there is a sufficient distance from the lower end of the opening edge of the flare forming mold 3 to the upper end of the glass tube support pin 2 to support the glass tube 1.
[0023]
In steps C, D, E, and F (FIGS. 3 to 6), the glass tube 1, the glass tube support pin 2, and the flare forming mold 3 perform a flare forming operation while maintaining rotation. In the flare forming step, two or more burners 5 for heating the vicinity of the upper end of the glass tube 1 are used. In step (FIG. 7), the flare opening edge pressing die 6 is used to press the flare opening edge to form a tapered portion of the flare in the softened glass tube. After the formation of the flare is completed, the process proceeds to the process (FIG. 8) and the process (FIG. 9) after the annealing process. In particular, in the middle of the flare forming step (FIGS. 3 to 7), the glass tube support pin 2 and the glass tube 1 are moved stepwise at least twice or more in a downward direction, so that the tapered portion of the flare 7 Prevents formation of glass wall and thickness deviation near the edge.
[0024]
In the flare forming steps C to F (FIGS. 3 to 6), the number of the plurality of heating burners 5 may be two or more, and the number is not particularly limited, but is usually two to four. According to the progress of the flare formation, the number of burners and the heating direction are optimally selected to supply a heating power for obtaining uniform softening of the glass tube and equalization of the flare shape.
[0025]
In the flare forming steps C to F, the glass tube 1, the glass tube support pin 2, and the flare forming mold 3 maintain a rotation speed of 1000 RPM or more, preferably in a range of 1000 to 1400 RPM. By the synergistic action of the centrifugal force of the flare forming mold 3 and the heating by the plurality of burners, the work of expanding the opening can be stably performed, and the uniformity of the flare taper can be reliably obtained.
[0026]
After annealing the flare 7 in step H (FIG. 8), the glass tube 1 and the glass tube support pin 2 are moved upward, and the flare 7 is taken out by the chuck 9 in step S (FIG. 9). Move to
[0027]
In the embodiment of the present invention, the flare opening edge pressing mold 6 shown in the flare forming step (FIG. 7) has a substantially funnel-like shape in which the tapered portion of the flare 7 is lightly assisted at its tip. , But this projection may be omitted. In the case of using the mold having the protruding portion, since the uneven thickness of the glass of the tapered portion does not occur at the time of forming the flare, it is possible to manufacture a flare with less cracks and scratches, and the opening portion and the cylindrical portion of the flare are formed. Because it is coaxial, the flare shape is stabilized. Further, as shown in an example in FIG. 7, the protruding portion is preferably formed in a cylindrical shape along the flare tube portion. Thereby, the flare taper shape is further stabilized, and the dimensional accuracy can be further improved.
[0028]
Further, the shapes and dimensions of the mold, the glass tube support pin, and the flare, the number of burners, the burner angle, the number of steps, and the like are not limited to the above description, and an optimum range can be appropriately selected.
[0029]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.
[0030]
(Example 1)
An experiment for forming a flare of a glass tube was performed based on the embodiment of the present invention. In the steps shown in FIGS. 1 to 9, the number of burners is set to two in step C, three in step D, four in step E, and three in step F. Then, the gas flame from the nozzle of the burner is sprayed toward the inner wall surface, and the flare forming mold 3 of 12 frames is moved between steps C and F, and is supported once in each of the steps D and F on the way. The pin 2 and the glass tube 1 were slightly lowered downward. The experiment was performed at a rotational speed of 1300 RPM of the glass tube 1, the support pin 2, and the flare forming mold 3 from the flare forming process C to F.
[0031]
In the process, the rotation of the glass tube 1, the support pin 2, and the flare forming die 3 was stopped, and the flare opening edge pressing die 6 without rotation was lowered to complete the flare 7.
[0032]
The flare 7 obtained by the method of the first embodiment also has a glass wall thickness of the tapered portion 10 and the opening edge 8 which is substantially uniform, distortion due to a wall-thickness, and a normal roundness and dimension of the flare shape. Was.
[0033]
(Comparative Example 1)
A flare 7 was produced in the same manner as in Example 1 except that the glass tube 1 and the support pins 2 were not lowered in the flare forming step.
[0034]
(Comparative Example 2)
Flare 7 was produced in the same manner as in Example 1 except that the number of burners 5 was changed to one in the flare forming step.
[0035]
(Comparative Example 3)
A flare 7 was produced in the same manner as in Example 1 except that in the flare forming step, the number of the burners 5 was one and the rotation speed of the glass tube 1 was 900 RPM.
[0036]
All of the flares 7 obtained by the methods of Comparative Examples 1 to 3 were not suitable for sealing with a tube container. That is, the roundness and dimension of the tapered portion 10 and the opening edge 8 of the flare 7 are not normal, and the flare 7 is not practical for lamp production due to the presence of uneven wall thickness and distortion.
[0037]
【The invention's effect】
As described above, according to the present invention, the glass tube is lowered stepwise a plurality of times while heating with a plurality of burners. It is possible to prevent the accumulation of meat near the edge of the opening. Therefore, it is possible to obtain a flare having normal and stable characteristics excellent in dimensional accuracy and shape of the flare, and also excellent in productivity. Therefore, it is suitable for sealing with a tube container and has a large practical effect.
[Brief description of the drawings]
FIG. 1 is a process chart (step a) showing an example of a method for producing a tube flare of the present invention.
FIG. 2 is a process chart (step B) showing an example of the method for producing a tube flare of the present invention.
FIG. 3 is a process diagram (process C) showing an example of the method for producing a tube flare of the present invention.
FIG. 4 is a process chart (step 2) illustrating an example of the method for producing a tube flare of the present invention.
FIG. 5 is a process diagram (process step E) showing an example of the method for producing a tube flare of the present invention.
FIG. 6 is a process chart (to steps) showing an example of the method for producing a tube flare of the present invention.
FIG. 7 is a process chart (process step) showing an example of the method for producing a tube flare of the present invention.
FIG. 8 is a process diagram (process step) showing an example of the method for producing a tube flare of the present invention.
FIG. 9 is a process diagram (process step) showing an example of the method for producing a tube flare of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Glass tube 2 Glass tube support pin 3 Flare forming die 4 Shaft core tube part 5 Burner 6 Flare opening edge pressing die 7 Flare 8 Opening edge 9 Chuck 10 Tapered portion

Claims (7)

A glass tube support pin slidable up and down is arranged on the shaft core tube portion of the rotatable flare forming mold, and a glass tube is arranged on the flare forming mold while being supported by the glass tube supporting pin, After heating the vicinity of the upper end of the glass tube with a plurality of burners, a pressing mold having a projection for engaging with the flare forming mold and forming a flare opening edge is applied to a heated portion of the glass tube. A method for producing a tube flare by pressing,
The glass tube, the glass tube support pin and the flare forming mold are heated by the burner while rotating, and the glass tube support is formed from the start of heating by the burner to the formation of a flare opening edge in the glass tube. A method of manufacturing a tube flare, comprising lowering a pin stepwise a plurality of times. The method for producing a tube flare according to claim 1, wherein the plurality of burners are arranged to heat at least two of an upper end surface, an outer wall surface, and an inner wall surface near an upper side of the glass tube. The method for producing a tube flare according to claim 1 or 2, wherein the pressing die has a protruding portion at a tip end of the protruding portion. The method for producing a tube flare according to any one of claims 1 to 3, wherein the glass tube, the glass tube supporting pin, and the flare forming mold are rotated at 1000 RPM or more. A rotatable flare forming mold in which a glass tube supporting pin slidable up and down is arranged in a shaft core tube portion,
A pressing mold having a convex portion capable of forming a flare opening edge by engaging with the mold ;
A plurality of burners for heating the glass tube near the upper end,
A flare manufacturing apparatus for a tube, comprising: the glass tube support pin that descends stepwise a plurality of times from the start of heating by the burner to the formation of a flare opening edge in the glass tube . The flare manufacturing apparatus for a bulb according to claim 5, wherein the plurality of burners are arranged so as to heat at least two of an upper end surface, an outer wall surface, and an inner wall surface near an upper side of the glass tube. 7. The apparatus for producing a flare for a tube according to claim 5, wherein the glass tube support pin and the flare forming mold are provided with means for rotating at 1000 RPM or more.

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