JP2004352598A - Press-molding device for optical lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press-molding device for an optical lens which can assure the precision of the optical lens with highly precise mold clamping when the optical lens is press-molded. <P>SOLUTION: The press-molding device is equipped with an upper die unit 1 fixing an upper die 3, a lower die unit 21 provided with a driving means 8 to travel a driving table 6 on which a lower shaft 2 attached with a lower die 4 is fitted in the vertical direction, and a guide mechanism 5 to guide the travelling of the driving table 6, and a column 10 to which the upper die unit 1 and the lower die unit 21 are oppositely fitted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

TECHNICAL FIELD OF THE INVENTION
[0001]
The present invention relates to an optical lens press molding apparatus used for manufacturing an optical lens by press molding.
[0002]
[Prior art]
An optical element such as an optical lens is formed by press-molding a glass material using an upper mold and a lower mold. In a molding apparatus used for such molding, it is important to accurately match the center axes of the upper mold and the lower mold in order to improve the optical characteristics of the optical element to be molded.
[0003]
For this reason, conventionally, an optical lens press molding apparatus shown in FIG. 4 has been developed. FIG. 4 is a cross-sectional view of a main part of the press forming apparatus, and FIG. 5 is a cross-sectional view for explaining a method of positioning an upper die and a lower die (for example, see Patent Document 1).
[0004]
In FIG. 4, a molding chamber 111 is formed by a casing 101, and an upper die 105 is fixed to an upper ceiling surface 101 b in the molding chamber 111 via a plate 103. A lower mold 106 is arranged at the upper end of the press shaft 104 so as to face the upper mold 105. The press shaft 104 is fixed to a slider 107, and the slider 107 is slidably installed in the bracket 102 via a high-precision guide device 108.
[0005]
The bracket 102 is attached to a lower bottom surface 101a of the housing 101, and is suspended by a support column 110 attached to the lower bottom surface 101a of the housing 101 without being in contact with other portions. A hydraulic cylinder 109 is fixed to a lower portion of the bracket 102, and a rod end of the hydraulic cylinder 109 is connected to a slider 107 via a swivel joint 115. Then, the hydraulic cylinder 109 pushes up the slider 107 to push up the press shaft 104 fixed to the slider 107, and the lower mold 106 is pressed against the upper mold 105 to clamp the optical lens to press-mold the optical lens.
[0006]
[Patent Document 1]
Japanese Patent Publication No. 7-55837 (page 2-3, FIG. 1, FIG. 5)
[0007]
[Problems to be solved by the invention]
However, the press forming apparatus shown in FIG. 4 has a structure in which the casing 101 and the bracket 102 connecting the upper mold 105 and the lower mold 106 are formed of different members, and the bracket 102 is suspended in the casing 101. Therefore, when positioning the upper die 105 and the lower die 106, the processing errors and the assembly errors of the constituent members are piled up, and the error of the entire apparatus becomes large. In order to reduce this error, it is necessary to manufacture each member with high accuracy and to assemble and adjust with high accuracy, so that a large number of man-hours are required, and the manufacture of the device is troublesome, There is a problem that the cost of the molding apparatus rises.
[0008]
In addition, since the housing 101 and the bracket 102 are formed of different members, the connection accuracy of the components cannot be maintained due to the expansion due to heat or the influence of the pressing force, and a change occurs. Cannot be done.
[0009]
Furthermore, since the housing 101 has a box shape, it is difficult to ensure processing accuracy (flatness, straightness, surface roughness) of the upper ceiling surface 101b on which the upper die 105 is mounted. Thus, it is difficult to ensure high relative accuracy between the upper ceiling surface 101b on which the upper die 105 is mounted and the lower bottom surface 101a of the housing 101 serving as the mounting reference for the lower die 106. For this reason, there occurs a problem that the axis of the upper mold 105 and the lower mold 106 is tilted, and the eccentricity of the processed lens deteriorates. Further, since the box-shaped casing 101 has poor heat dissipation, heat during molding by a heating means (not shown) is trapped in the casing 101, and the heat causes the casing 101 to be deformed. As described above, the press forming apparatus shown in FIG. 4 has a problem that the mold matching accuracy cannot be ensured.
[0010]
On the other hand, as shown in FIG. 5, a positioning hole 114 is provided in the upper die 105, and a positioning pin 113 fitted in the positioning hole 114 is fixed to the lower die 106, as shown in FIG. That has been done. In this structure, the positioning accuracy of the upper die 105 and the lower die 106 is ensured by inserting the positioning pins 113 into the positioning holes 114 at the time of die clamping.
[0011]
However, even in the case of the structure shown in FIG. 5, due to the clearance between the positioning holes 114 and the positioning pins 113 and their shape change due to heat, they are not sufficient for high-precision processing. .
[0012]
The present invention has been made in view of such a conventional problem, and can ensure high precision at the time of mold clamping for press-molding an optical lens. It is an object of the present invention to provide an optical lens press molding device capable of ensuring the precision of the optical lens.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, a press molding apparatus for an optical lens according to the first aspect of the present invention includes an upper mold unit to which an upper mold is fixed, a lower shaft to which a lower mold is attached, and a drive table. It is characterized by comprising a lower mold unit having a driving mechanism for moving vertically and a guide mechanism for guiding the movement of the drive table, and a column in which the upper mold unit and the lower mold unit are attached to face each other. I do.
[0014]
According to the first aspect of the present invention, the upper mold unit and the lower mold unit are mounted to face the column, and the lower shaft having the lower mold is guided by the guide mechanism. Since the axial center can be easily maintained with high accuracy, and the influence of heat during molding can be suppressed, the molding accuracy of the optical lens to be molded can be improved.
[0015]
According to a second aspect of the present invention, there is provided the optical lens press-molding apparatus according to the first aspect, wherein each axis of the lower mold, the lower shaft, the drive table, and the drive means is arranged on the same plane. Features.
[0016]
According to the second aspect of the present invention, since the lower mold, the lower shaft, the drive table, and the drive means, which constitute the lower mold unit, are arranged on the same plane, they can be positioned with high accuracy. .
[0017]
According to a third aspect of the present invention, there is provided the optical lens press forming apparatus according to the first aspect, wherein the guide mechanism is a linear guide.
[0018]
By using the linear guide in this way, the lower shaft can be moved with extremely high accuracy, and thus the mold can be clamped while maintaining the relative position accuracy between the upper die and the lower die with high accuracy.
[0019]
According to a fourth aspect of the present invention, there is provided the optical lens press forming apparatus according to the first or second aspect, wherein the driving means is a linear servomotor.
[0020]
According to the present invention, the use of the linear servomotor as the driving means eliminates the need for a bearing portion for receiving a load as compared with the case where a ball screw is used, so that the positioning accuracy caused by the rigidity of the bearing portion does not decrease.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to an embodiment. FIG. 1 is a front view of an optical lens press forming apparatus according to an embodiment of the present invention, and FIG. 2 is a side view thereof.
[0022]
The press forming apparatus according to the present embodiment includes an upper mold unit 1, a lower mold unit 21, and a column 10 for attaching the same, and the column 10 is fixed upright on a base 11. ing. The upper unit 1 is attached to the upper part of the column 10, and the lower unit 21 is attached to the lower part of the column 10 so as to face the upper unit 1.
[0023]
The upper die 3 is fixed to the upper die unit 1 with high accuracy. The upper unit 1 is mounted on a column mounting surface 10a of the column 10. The upper die unit 1 is mounted after being adjusted with high accuracy so that the upper axis is parallel to the column mounting surface 10a.
[0024]
The lower die unit 21 has a lower die 4, and the lower die 4 is attached to the lower shaft 2 with high accuracy, and the lower shaft 2 is attached to the slide table 6 as a drive table. The slide table 6 is mounted on the column mounting surface 10a of the column 10 via the guide mechanism 5. As shown in FIG. 1, the guide mechanism 5 has two sliding shafts 5a parallel to each other and attached to the column mounting surface 10a, and the slide table 6 is vertically moved along the sliding shaft 5a. Moving.
[0025]
A driving device 8 as driving means is connected to a lower portion of the slide table 6 via a high-precision ball screw 7 to operate the table 6 in a vertical direction. The driving device 8 is fixed to a bracket 9, and the bracket 9 is fixed to a mounting surface 10 a of the column 10. In this case, a servomotor with a brake is used as the driving device 8.
[0026]
With the above-described configuration, in this embodiment, the upper die unit 1, the slide table 6, and the driving device 8 are mounted using the column mounting surface 10a of the column 10 as a common reference. Can be positioned with high precision with respect to the column mounting surface 10a of the reference surface. That is, the respective axes of the lower mold 4, the lower shaft 2, the slide table 6, and the driving device 8 are arranged on the same plane with respect to the column mounting surface 10a of the column 10.
[0027]
In addition, the periphery of the upper mold unit 1 and the lower mold unit 21 has a structure in which only one surface is surrounded by the column mounting surface 10a of the column 10, and the other three surfaces are open. The column 10 to which the upper mold unit 1 and the lower mold unit 21 are attached has an upright posture by being fixed on the base 11.
[0028]
In the molding of the optical lens according to the present embodiment, first, an appropriate amount of a glass material (not shown) for molding into an optical lens is placed on the lower mold 4 by a carrying device (not shown). Subsequently, the servomotor with the brake used as the driving device 8 is rotated, and the slide table 6 is raised via the high-precision ball screw 7. As the slide table 6 rises, the lower mold 4 on which a glass material (not shown) is placed also rises, and mold clamping is performed between the lower mold 4 and the opposing upper mold 3 to form an optical lens.
[0029]
In such an embodiment, since the upper die unit 1 having the upper die 3 and the lower die unit 21 having the lower die 4 are attached to the column 10, the axes of the upper die 3 and the lower die 4 can be precisely formed. Coaxiality can be ensured. Further, since the three surfaces other than the mounting surface 10a of the column 10 to which the upper die 3 and the lower die 4 are mounted can be released, the heat radiation efficiency is improved, and the upper die unit 1, the lower die unit 21, and these The influence of heat during molding on the column 10 to which the units 1 and 21 are attached is reduced. Thereby, the precision can be maintained for a long time, and the upper mold 3 and the lower mold 4 can be clamped with high precision without using a positioning member or the like. Specifically, high-precision molding with a shift error of within ± 10 μm and a tilt error of within ± 0.5 minutes can be maintained for a long time. Further, since the structure is extremely simple, the cost of the molding machine can be reduced, and the manufacturing cost of the optical lens can be reduced.
[0030]
In this embodiment, a servomotor with a brake is used as the driving device 8, but a hydraulic / pneumatic cylinder, a torque motor, or the like may be used.
[0031]
In order to move the slide table 6, the guide mechanism 5 and a linear servomotor may be combined and driven. By using a linear servomotor in this way, there is no need for a bearing portion to receive a load, as compared with the case where a ball screw is used. Therefore, there is an advantage that the positioning accuracy does not decrease due to the rigidity of the bearing portion.
[0032]
Further, in this embodiment, the axes of the driving device 8, the lower shaft 2, the lower die 4, the upper die 3, and the upper die unit 1 are coaxially arranged on a plane parallel to the column mounting surface 10a. Although only the sliding shaft 5a of the guide mechanism 5 is on another plane, an arrangement as shown in FIG. 3 can be performed. That is, in FIG. 3, the sliding shaft 5a of the guide mechanism 5 is arranged on the same plane as the axis of the driving device 8, the lower shaft 2, the lower die 4, the upper die 3, and the upper die unit 1. By doing so, a load acting during molding is not received as an eccentric load.
[0033]
【The invention's effect】
According to the first aspect of the present invention, high precision coaxiality of the axis can be ensured with an inexpensive structure, and the three surfaces can be released, so that the influence of heat during molding is reduced, and the molding of the optical lens is reduced. High accuracy can be maintained for a long time.
[0034]
According to the second aspect of the invention, in addition to the effect of the first aspect, the lower mold, the lower shaft, the drive table, and the drive means constituting the lower mold unit can be positioned with high accuracy.
[0035]
According to the third aspect of the invention, in addition to the effects of the first aspect, the mold can be clamped while maintaining the relative positional accuracy of the upper mold and the lower mold with high accuracy.
[0036]
According to the fourth aspect of the present invention, in addition to the effects of the first and second aspects of the present invention, it is possible to prevent the occurrence of an eccentric load due to a load caused by molding, so that a highly accurate optical lens can be molded. .
[Brief description of the drawings]
FIG. 1 is a front view of a press forming apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a side view of the press forming apparatus.
FIG. 3 is a plan view of a lower mold unit in another press molding apparatus.
FIG. 4 is a front view of a conventional press forming apparatus.
FIG. 5 is an enlarged view of a positioning portion of a conventional mold.
[Explanation of symbols]
Reference Signs List 1 Upper die unit 2 Lower shaft 3 Upper die 4 Lower die 5 Guide mechanism 6 Slide table 7 High precision ball screw 8 Drive unit 9 Bracket 10 Column 10a Column mounting surface 21 Lower die unit

Claims (4)

An upper mold unit to which the upper mold is fixed, a lower shaft to which the lower mold is attached are attached to the drive table, and a lower unit including a drive unit for moving the drive table in the vertical direction and a guide mechanism for guiding the movement of the drive table. A press molding apparatus for an optical lens, comprising: a mold unit; and a column in which an upper mold unit and a lower mold unit are mounted so as to face each other. 2. The optical lens press-forming apparatus according to claim 1, wherein respective axes of the lower mold, the lower shaft, the drive table, and the drive unit are arranged on the same plane. 2. The apparatus according to claim 1, wherein the guide mechanism is a linear guide. 3. The optical lens press forming apparatus according to claim 1, wherein said driving means is a linear servomotor.

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