JP2012072020A - Press forming die for reflection mirror base body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press forming die which is used for forming a reflection mirror base body having a concave curved surface and which effectively prevents the occurrence of shape defects or the like in the reflection mirror base body.SOLUTION: The thickness T from the press forming surface 41 of a plunger 4 to the inner wall surface of a flow passage 5 of a cooling medium for cooling the press forming surface 41 is formed nearly constant over the whole press forming surface 41. Thereby, the surface temperature of the press forming surface 41 of the plunger 4 is made uniform, and the concave curved surface C of the reflection mirror base body G is exactly formed in accordance with the shape of the press forming surface 41.

Description

  The present invention relates to a press-molding die for a reflecting mirror base, and more particularly to a press-molding die for press-molding a reflecting mirror base made of a glass material.

  A light source lamp of an illuminating device, a projector or the like generates more heat as it becomes brighter, and the temperature rise of the reflector used in combination with the light source lamp also increases. In particular, in recent years, the brightness of light source lamps and the miniaturization thereof have progressed in various fields, and the reflecting mirror portion has a high temperature exceeding 550 ° C. In general, a reflecting mirror is composed of a substantially bowl-shaped reflecting mirror substrate having a concave curved surface opened in one direction, and a reflective film coated on the concave curved surface, both of which need to have heat resistance characteristics that can withstand high temperatures. . Therefore, at present, a reflector substrate made of crystallized glass that can withstand higher temperatures has been used.

  As shown in FIG. 2, the glass reflector base G is provided with a molten glass lump (gob) (not shown) in a receiving mold 300 formed by combining a shell mold (ring mold) 200 on a bottom mold (bottom mold) 100. , And the molten glass lump is stretched by a pressing die comprising a plunger 400 and pressed into a predetermined shape.

  Usually, the press-molding surface 410 of the plunger 400 becomes high temperature due to contact with the molten glass, and causes problems such as seizure, so that sufficient cooling is required. Conventionally, as shown in FIG. 2, the cooling of the plunger is performed by circulating a cooling medium such as cooling water through a flow path 500 configured by inserting a supply pipe 520 into a cavity 510 formed in the plunger 400. Is going. That is, the flow path 500 of the plunger 400 includes an inner passage 530 in the pipe of the supply pipe 520, a cooling chamber 540 between the distal end portion of the supply pipe 520 and the inner surface of the distal end side of the plunger 400, and an outer surface of the supply pipe 520. The outer passage 550 between the inner surface of the plunger 400 and the inner passage 530, the cooling chamber 540, and the outer passage 550 are circulated in this order as shown by arrows in FIG. The press molding surface 410 of the plunger 400 is cooled.

  Conventionally, as the cooling structure of the plunger, those described in the following Patent Documents 1 to 3 are known. These are a non-uniform surface temperature of the press molding surface by arranging a good heat conduction layer and a heat insulating layer inside the plunger, and promoting or suppressing the heat transfer in the plunger in the direction along the press molding surface. To prevent the occurrence of defects such as the shape, cracks, and cracks of the glass molded product.

  However, these plungers described in Patent Documents 1 to 3 are intended for molding a relatively large glass molded product such as a TV cathode ray tube panel. Even if it is applied to the molding of a small glass molded product of about 30-100 grams like a mirror base, the occurrence of shape defects cannot be effectively prevented, and the concave curved surface of the reflector base is press-molded with a plunger. There was a difficulty that could not be accurately molded according to the shape of the surface. In other words, in the case of a small glass molded product such as a reflector substrate, since the total amount of heat of the molten glass to be molded is small, the influence of variations in the surface temperature of the plunger on the molded shape of the concave curved surface of the reflector substrate is remarkable. Therefore, the uniformity of the surface temperature of the plunger is more severely required for the press molding of the concave curved surface of the reflector substrate.

JP-A-7-220737 JP-A-9-227142 JP-A-9-202628

  The present invention was made in view of the above-mentioned drawbacks in conventional press molding dies, and the surface temperature of the plunger is made more uniform to effectively generate the shape defect of the reflector substrate. It is an object of the present invention to provide a press mold that can be prevented.

  As a result of intensive studies to make the surface temperature of the plunger that press-molds the reflector substrate more uniform, the present inventors have found that the total amount of heat of the molten glass lump used to mold the reflector substrate is small, and further the reflection Since the thickness of the mirror substrate is substantially constant, the heat distribution of the reflecting mirror substrate during press molding is noted to be substantially constant, and the present invention has been completed by actively utilizing this.

That is, the present invention comprises a receiving mold in which a shell mold is combined on a bottom mold, and a plunger that presses a molten glass lump supplied to the receiving mold to press-mold a reflector substrate having a predetermined shape. A molding die for a reflector substrate comprising a pressing die,
A flow path for a cooling medium that cools a press-molded surface that comes into contact with molten glass during press molding among the outer surfaces of the plunger is provided inside the plunger, from the press-molded surface of the plunger to the inner wall surface of the flow path Is characterized by being substantially constant over the entire pressing surface.

  Further, the present invention is characterized in that the flow path is configured by inserting a supply pipe into a hollow portion formed in the plunger.

  Further, the present invention is characterized in that the cooling medium flowing through the flow path is water.

  According to the molding press mold of the reflector base according to the present invention, the thickness of the plunger is formed substantially constant over the entire press molding surface, so that the press molding surface is cooled by the cooling medium flowing through the flow path. The entire surface of the can be evenly cooled. Therefore, the surface temperature of the press-molding surface that receives heat almost uniformly from the molten glass having a substantially constant heat distribution can be made more uniform, and the concave curved surface of the reflector substrate can be accurately matched to the shape of the press-molding surface of the plunger. Can be molded.

  In addition, if a flow path is configured by inserting a supply pipe into the cavity formed in the plunger, and water is used as a cooling medium for circulating the flow path, the cooling structure of the plunger can be simplified. In particular, it is suitable as a relatively small plunger cooling structure for press-molding a small reflector substrate.

It is a longitudinal cross-sectional view of the shaping | molding press metal mold | die of the reflector base body of this embodiment. It is a longitudinal cross-sectional view of the shaping | molding press metal mold | die of the conventional reflective mirror base | substrate.

  As shown in FIG. 1, a reflector press mold 10 for reflecting mirror substrate of the present embodiment is mainly supplied to a receiving mold 3 in which a shell mold 2 is combined on a bottom mold 1 and supplied to the receiving mold 3. A pressing die composed of a plunger 4 for press-forming a reflecting mirror base G having a predetermined shape by extending a molten glass lump (not shown) from above, and a flow path 5 for circulating a cooling medium for cooling the press-forming surface 41 of the plunger 4. , Is composed of.

  The bottom mold 1 has a concave press-molding surface 11 having a predetermined shape on the upper part thereof, and the outer surface of the reflector substrate G is molded by the press-molding surface 11.

  The shell mold 2 has a substantially annular shape, and has a press-molding surface 21 at a lower portion of the inner edge, and is reflected by the press-molded surface 21 while being placed on the upper surface of the bottom mold 1. The upper edge portion of the mirror base G is molded.

  The plunger 4 has a convex press-molding surface 41 having a predetermined shape at the tip thereof, and the concave curved surface C of the reflecting mirror base G is molded by the press-molding surface 41.

  Thus, by the molding press mold 10 of the present embodiment, the substantially mirror-shaped reflector substrate G having the concave curved surface C opened in one direction and having a substantially constant thickness is press-molded. Thereafter, in a separate process, a reflective film is coated on the concave curved surface C of the reflector base G to form a reflective surface. The concave curved surface C of the reflecting mirror base G is constituted by, for example, a parabolic surface, an elliptical surface, another curved surface, or a combination thereof.

  Further, on the outer surface of the plunger 4 above the press molding surface 41, a facing surface 42 is formed which faces the shell mold 2 at the time of press molding. That is, as shown in FIG. 1, the outer surface of the plunger 4 includes a press molding surface 41 that comes into contact with the molten glass during press molding, and a facing surface 42 that faces the shell mold 2 during press molding.

  The flow path 5 is provided inside the plunger 4. The flow path 5 of the present embodiment includes a cavity 51 formed in the plunger 4 and a supply pipe 52 inserted into the cavity 51. That is, the flow path 5 of the present embodiment includes an inner passage 53 in the pipe of the supply pipe 52, a cooling chamber 54 between the distal end portion of the supply pipe 52 and the inner surface on the distal end side of the plunger 4, and the outer surface of the supply pipe 52. And an outer passage 55 between the plunger 4 and the inner surface of the plunger 4. As shown by the arrows in FIG. 1, the plunger 4 that receives heat by contact with the molten glass by circulating a cooling medium made of cooling water in the order of the inner passage 53, the cooling chamber 54, and the outer passage 55. The entire molding surface 41 is cooled.

  The plunger 4 is formed so that the thickness T from the press molding surface 41 to the inner wall surface of the flow path 5 is substantially constant over the entire press molding surface 41. That is, the shortest distance between the press molding surface 41 and the inner wall surface of the flow path 5 is substantially constant at any position on the press molding surface 41. The thickness T is formed to be smaller than the radius of curvature at any position on the press molding surface 41.

  As described above, according to the molding press mold 10 of the reflecting mirror substrate of the present embodiment, the thickness T of the plunger 4 is formed substantially constant over the entire press molding surface 41, so that the circulation channel 5 is circulated. The entire surface of the press molding surface 41 can be uniformly cooled by the cooling water. Accordingly, the surface temperature of the press-molding surface 41 that receives heat almost uniformly from the molten glass having a substantially constant heat distribution can be made more uniform, and the concave curved surface C of the reflector substrate G can be made to be It can be accurately molded according to the shape.

  In the present invention, “the thickness T of the plunger 4 is formed to be substantially constant over the entire press molding surface 41” means from the press molding surface 41 of the plunger 4 to the inner wall surface of the flow path 5. It means that the maximum value and the minimum value of the wall thickness T are within a range of ± 10% with respect to the average wall thickness of the plunger 4.

  In addition, the reflector base molding press die 10 of the present embodiment is configured such that the supply path 52 is inserted into the cavity 51 formed in the plunger 4 to form the distribution path 5 and the cooling medium that distributes the distribution path 5. Since water is employed, the cooling structure of the plunger 4 can be simplified. Therefore, it is suitable as a cooling structure for the relatively small plunger 4 for press-molding a relatively small reflector substrate G of about 30 to 100 grams.

  As mentioned above, although the press mold 10 for glass forming of this embodiment was demonstrated, this invention can be implemented also with another form.

  For example, in the above embodiment, the thickness of the facing surface 42 of the plunger 4 is the same as the thickness T of the press-molding surface 41, but the present invention is not limited to this, and the facing of the plunger 4 is not limited to this. The wall thickness on the surface 42 may be larger than the wall thickness T on the press molding surface 41. This is because the amount of heat received by the facing surface 42 via the shell mold 2 is smaller than the amount of heat directly received by the press-molded surface 41 from the molten glass.

  Moreover, in the said embodiment, although water is employ | adopted as a cooling medium which distribute | circulates the flow path 5, this invention is not limited to this, Gases, such as other liquids and air, are employ | adopted as a cooling medium. May be.

  The present invention can be carried out in other modes without various modifications, modifications, and variations based on the knowledge of those skilled in the art without departing from the spirit of the present invention. In addition, any invention-specific matters may be replaced with other technologies within a range where the same action or effect occurs, and the integrally-configured invention-specific matters are constituted by a plurality of members. Alternatively, the invention specific items configured by a plurality of members may be implemented in an integrated configuration.

DESCRIPTION OF SYMBOLS 10 Forming press die 1 of reflecting mirror base 1 Bottom die 2 Shell die 3 Receiving die 4 Plunger 41 Press molding surface 5 Flow path 51 Cavity 52 Supply pipe G Reflector base T From press molding surface to inner wall surface of flow path Wall thickness

Claims (3)

A receiving mold comprising a combination of a shell mold on a bottom mold, and a pressing mold comprising a plunger that presses a molten glass lump supplied to the receiving mold to press-mold a reflector substrate of a predetermined shape. A molding press mold for a reflector substrate,
Inside the plunger, a flow path of a cooling medium for cooling a press-molded surface that comes into contact with the molten glass at the time of press molding of the outer surface of the plunger is provided,
A molding press mold for a reflector substrate, wherein the thickness of the plunger from the press molding surface to the inner wall surface of the flow path is formed substantially constant over the entire press molding surface.   The said flow path is comprised by inserting a supply pipe | tube in the cavity formed in the said plunger, The shaping press metal mold | die of the reflector base | substrate of Claim 1 characterized by the above-mentioned.   The molding die for a reflector substrate according to claim 1 or 2, wherein the cooling medium flowing through the flow path is water.

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