JPS60210533A - Molding method of glass member - Google Patents

Abstract

PURPOSE:To obtain a thin-walled glass member capable of cutting off unnecessary parts easily by squeezing out one part of melted glass to an outflow part of specified molding mold and simultaneously forming a notch to the squeezed part. CONSTITUTION:Melted glass more than necessary quantity is supplied to a bottom mold 4 and a top mold 5 and a pressing mold 6 are descended and pressed by actuating a plunger to move the melted glass between said molds 4, 5 and a flange part 9 is formed with a stepped part 7 of surrounding edges of said force 4 and said mold 6 to squeeze out excess glass to an outflow part 12. After a projected line 14 having triangle-shaped cross section provided to said force 6 is abutted on a squeezed part 13 to form a notch cut along the outside face of the flange 9, the glass of said squeezed part of the formed glass member is cut off from the position of said notch with a cutter or a burner to obtain a desired molding member.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding glass members such as NI single-sided lenses and reflectors used in N1J lighting for automobiles and the like.

Conventionally, in the suppression molding method for glass members used in headlights of automobiles, etc., for example, the molding of a rectangular front lens is explained with reference to FIG. 1. Lower mold 1 with four parts formed according to the shape
an upper mold 2 having a convex portion having the inner surface shape of the front lens formed above the recessed portion 2, and a flange portion of the front lens that engages with the open periphery of the upper mold 2 and the lower mold 1; In this method, a compression molding device consisting of a presser mold 3 for molding is used, molten glass of a desired company is supplied to the lower mold 1, and compression molding is performed using an upper mold 2 and a presser mold 3.

When molten glass is compressed, the molten glass pressed by the convex part of the upper mold moves upward along the inner surface of the recessed part of the lower mold according to the compression stroke of the upper mold. Because the flow speed of the molten glass is different, the molten glass tends to flow concentrated in the thicker portions, and does not flow sufficiently into the thinner portions. The molten glass that has flowed upward through the thicker portion is then molded into a flange by the presser, and at the same time the excess glass is distributed over the thinner portion.

However, according to this compression molding method, the molten glass loses heat through the upper mold and the lower mold, and detours through the mold by the presser mold flea, so that the viscous resistance of the molten glass increases rapidly. Therefore, it was a national crisis to mold the wall to be thinner than a certain level.

BACKGROUND OF THE INVENTION In recent years, there has been a demand for lighter automotive headlamps, and it has become necessary to reduce the weight of glass members such as front lenses and reflectors used in headlamps, that is, to make the glass thinner.

Methods for forming the glass members of headlights into thinner walls include ■ changing the manufacturing method, ■ changing the shape of the product such as thickness distribution, and ■ changing the molding conditions. This change involves changing the materials of the melting furnace, four-house, spout, orifice, refractory plunger, etc., and there are various problems in practice.

Regarding the manufacturing method in item (2), Japanese Patent Publication No. 42-23951 discloses a method for molding a cathode ray tube for a television set as a method for molding a thin-walled glass container. That is, the molten glass supplied to the lower mold is compressed between the lower mold and the upper mold, and a part of the molten glass is made to protrude into an outflow portion provided at the contact edge of the lower mold and the upper mold. This is a method for forming thin-walled glass containers, in which the molded glass container is molded, and the protruding portion of the molded glass container is cut with grooves.

However, this molding method only uses an upper mold and a lower mold to form a glass container, so when it is applied to front-facing lenses for headlights, there is no presser mold to mold the flange part, so it is difficult to set the shape of the flange part. This method is particularly unsuitable for molding glass members that have complicated shapes and require precision, such as front lenses. Furthermore, in addition to the glass pressing process, a separate process of making cuts in the protruding portions is required.

The present invention has been made in view of the above circumstances, and uses an upper mold, a lower mold, and a presser mold to press molten glass, and causes a part of the molten glass to protrude onto the open periphery of the lower mold, and at the same time, to The present invention aims to provide a molding method that allows a thin glass member to be easily obtained by forming incisions.

The present invention presses the molten glass supplied to the lower die between the lower die, the upper die, and the presser die, and the molten glass is poured into an outflow portion provided between the peripheral edge of the lower die and the presser die. This method of molding a glass member is characterized in that a portion of the glass member is made to protrude, and at the same time, a cut is formed in the protruding portion by a protrusion formed on one or both of a lower die and a presser die.

The present invention will be explained with reference to an illustrated embodiment, taking as an example the molding of a front lens of a headlamp. In Figures 2 and 3, 4 is a lower mold with a substantially rectangular opening facing upward, and a convex part facing downward on the open side of the lower mold 4, facing the concave part of the lower mold 4. An upper mold 5 and a presser mold 6 that engages with the open peripheral edges of the upper mold 5 and the lower mold are provided. A stepped portion 7 is formed on the open peripheral edge of the lower die 4 and abuts against the flange portion 9 of the forward-facing lens 8 . A surface 10 of the presser die 6 that comes into contact with the flange portion 9 forms an outflow portion 12 of the protruding glass in correspondence with the peripheral edge surface 11 of the lower die 4 . Further, in order to form a cut in the protruding portion 13 along the outer surface of the flange portion 9, a protrusion 14 having a triangular cross section is provided on the presser die 6. 15 is a stopper of the presser die 6.

In the suppression molding apparatus configured in this way, the lower mold 4
After supplying a larger amount of molten glass than required, actuate the plunger (not shown) to lower and press the upper die 5 and the presser die 6, and the molten glass will be separated into the upper die 5 and the lower die 4. The flange portion 9 is formed by the stepped portion 7 on the periphery of the lower mold 4 and the holding die, and the excess glass protrudes into the outflow portion 12. The protruding portion 13 is connected to the flange portion 9 by the protrusion 14.
A groove or cut having a triangular cross-section is formed along the outer surface of the groove. The thickness of the glass at this cut part is 1 to 2 m.
The degree is appropriate.

The glass member formed by the above method can be cut out from the protruding portion of the glass by a known cutting method using a cutter, burner, etc. to obtain a desired product.

In this example, a protrusion was provided on the presser die to form the notch in the protruding part, but it is also possible to provide the protrusion on the peripheral edge of the lower die, or to provide the protrusion on the periphery of the lower die. Exactly the same effect can be obtained. FIG. 4 shows an example in which a protrusion is provided on the peripheral edge of the lower mold.

Next, the area where the molten glass protrudes in the compression molding of the present invention differs slightly depending on the shape of the glass member to be molded. For example, in the case of a front lens or reflector with a rectangular opening cross section, the four corners are generally molded to be thicker than the other parts, so when pressed, the viscous resistance will be reduced. The molten glass reaches the outflow part earlier than the other parts at the four small corners, and the mold is formed with the glass protruding from the four corners. % for glass parts for headlights
In the case of a hiJ surface lens, it is appropriate to make it protrude to the four corners or to the short side including the four corners, and in the case of a reflective mirror, it is made to protrude to the long side including the four corners, which is suitable for obtaining a desired thin glass member. In addition, in the case of the front lens of a circular sealed beam type headlamp, the wall thickness is almost uniform, so the lens protrudes over the entire periphery.

It has been confirmed that the thin glass member for headlights formed by the method of the present invention has practically no problems in terms of mechanical strength, heat resistance, and other properties.

Further, the molding method of the present invention is not limited to molding glass members for headlights, but can also be applied to molding glass containers such as P4IV of cathode ray tubes for televisions, funnels, and tableware. Similar effects can be obtained.

As described in detail above, the present invention provides a mold with a small flow resistance without imparting resistance to the molten glass that is pressed and flows upward by supplying an excess amount of molten glass to the mold. By allowing the material to protrude upward rather than sticking to a certain area, sufficient pressure can be applied to areas with low flow resistance, and the advantage is that the material can be compressed into a considerably thin wall.

Furthermore, since a cut is formed in the protruding glass at the same time as the suppression, there is an advantage that unnecessary protruding portions can be easily removed immediately after molding. In this way, a lightweight, ie, thin glass member can be obtained.

Further, the present invention has the effect that a desired thin-walled glass member can be molded without significantly changing the conventional suppression method and molding conditions, and without changing the thickness distribution and shape of the product.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an apparatus to which a conventional glass member forming method is applied, FIG. 2 is a cross-sectional view showing an embodiment of an apparatus using the glass member forming method of the present invention, and FIG. FIG. 4 is an enlarged cross-sectional view of the main part showing one embodiment of the cut of the milled part, and FIG. 4 is an enlarged one-plane view of the main part showing another embodiment. 1.4-...Lower mold, 2.5...Upper mold 3.6
-... Presser die, 12 -... Outflow part 13
・・・・・・Protruding part, 14・・・・・・・・・・・・
・Protrusions. Patent issued ji+, +i person Toshiba Glass Co., Ltd. drawing engraving (
(No change in content) Figure 1 Figure 2 Figure 3 Figure 4 Procedural amendment (voluntary) Commissioner of the Japan Patent Office 1 Indication of the case Patent application No. 64815 filed in 1982 Title of the invention Method for forming glass members 1 Interaction with the case of the person making the amendment Patent applicant's application, specification and drawings & contents of amendment

Claims (1)

[Claims] The molten glass supplied to the lower die is pressed between the lower die, the upper die and the presser die, and a part of the molten glass is poured into the outflow part provided between the peripheral edge of the lower die and the presser die. A method for molding a glass member, characterized in that, at the same time as the glass member is caused to protrude, a notch is formed in the protruding portion by a protrusion formed on one or both of a lower die and a presser die.