JP2004066773A - Lens frame integrating mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens frame integrating mold in which the centering of a lens and a lens frame can be easily executed by simplifying a centering mechanism of the lens, and at the same time, which has no occurrence of defect parts of a resin on a lens storage wall of the lens frame. <P>SOLUTION: The lens frame integrating mold is for molding the lens frame by inserting the lens 7 and by filling the resin to the outer peripheral part of the lens 7. The mold is provided with a movable core 9 having nearly the same outer diameter as the outer periphery of the lens 7 and of which the tip is in a bell-clamp shape, a stationary core 2 arranged opposingly to the movable core 9 and of which the tip is in a bell-clamp shape, and an annular member 10 which is fitted to the movable core 9 and is movable back and forth in the direction parallel to the center shaft of the lens 7. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a so-called lens insert molding die for integrally molding a lens and a lens frame on an outer peripheral portion thereof.
[0002]
[Prior art]
A technique for integrally molding a lens and a lens frame with a resin after inserting the lens into a mold and automatically centering the lens is disclosed in, for example, Japanese Patent Application Laid-Open No. The technology disclosed in Japanese Patent No. 16820 is disclosed. In this prior art, the means for centering the lens installed in the molding apparatus is provided with a slide core movable in a plane perpendicular to the optical axis of the lens and supporting at least three points on the outer periphery of the lens. The centering is performed by bringing the lens into contact with the outer periphery of the lens. The means for preliminarily holding the lens includes a suction port in which the diameter regulating core in the upper cavity and the diameter regulating core in the lower cavity elastically hold the lens and communicate with the diameter regulating core in the lower cavity. The lens is adsorbed by the device.
[0003]
Means for moving the slide core for centering the lens will be described. A rotating annular slide plate is engaged with the three slide cores, and the slide core moves forward and backward due to a change in a position where a cam surface provided on the slide plate comes into contact with a cam surface of the slide core. The rotation of the slide plate is performed by a drive mechanism including a gear engraved on the outer periphery of the slide plate, an intermediate gear having a clutch that meshes with the gear, and a motor having a motor gear that meshes with the intermediate gear. The slide core is moved forward by driving the motor to rotate the slide plate via the clutch. The three slide cores in contact with the lens further advance, and when the lens pressing force of the slide core reaches a set value when the centering of the lens is completed, the clutch slips and the motor stops. The retraction of the slide core is performed by reversing the motor.
[0004]
[Problems to be solved by the invention]
However, the above prior art has the following problems. That is, since the centering mechanism of the lens is complicated, there are the following problems.
1. It is difficult to match the shape between the slide core and the lens in the lens support.
2.3 It is difficult to eliminate the axial displacement of the lens on the same plane by the lens support portions of the three slide cores.
3. Forming the cam shape of the slide plate for moving the slide core forward and backward is difficult in terms of mold processing and mold adjustment, and increases mold processing costs and mold adjustment costs.
4. Since the clutch slides when the slide core advances and abuts the outer periphery of the lens and the centering is completed, it is difficult to adjust the power of the clutch in the control method of stopping the intake device and the motor due to the slip of the clutch.
5. The complexity of the centering mechanism increases the molding cycle.
[0005]
6. Since the lens frame is formed while the slide core supporting the lens is in contact with the outer periphery of the lens, the portion of the lens housing wall has a shape in which the resin is missing, and there is a problem in lens frame quality as follows.
{Circle around (1)} Light leakage and irregular reflection occur at the missing portion of the resin.
{Circle around (2)} Smear coating is required to prevent irregular reflection of the missing portion of the resin.
{Circle over (3)} The molding shrinkage ratio between the missing portion and the filled portion of the resin changes, and it is difficult to ensure required accuracy such as roundness, interference fringes, and outer diameter of the lens-molded frame integrally molded product.
[0006]
The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention according to claim 1 or 2 is to simplify a centering mechanism of a lens, to facilitate centering between a lens and a lens frame. It is another object of the present invention to provide a lens frame integral molding die in which resin missing portions do not occur on the lens housing wall of the lens frame.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 or 2 is a lens barrel integral molding die in which a lens is inserted and a resin is filled in an outer peripheral portion of the lens to form a lens barrel. A movable core having an outer diameter substantially the same as the outer diameter and having a bell-clamp tip at the tip, a fixed core having a bell-clamp tip disposed opposite to the movable core and fitted to the movable core; And an annular member capable of moving back and forth in a direction parallel to a central axis of the lens.
[0008]
In the lens frame integral molding die according to the first or second aspect of the present invention, a movable core having an outer diameter substantially the same as the outer circumference of the lens and having a bell-clamp-shaped tip is disposed to face the movable core. In addition, a fixed core having a bell clamp shape at the tip and an annular member fitted to the movable core and capable of moving back and forth in a direction parallel to the central axis of the lens are provided, so that the annular member is raised in the central axis direction of the lens Then, align the outer circumference of the lens with the inner diameter of the lens, insert the lens, and place the lens on the tip of the bell clamp shape of the movable core. Hold the lens in between and fix it.
[0009]
In the lens-mold-integrated mold according to the second aspect of the invention, in addition to the above operation, the fixed core is urged by the elastic member in the direction of the movable core, and a suction device is provided at the center of the movable core. Is provided with a suction passage communicating with the movable core, the suction device sucks the lens mounted on the movable core through the suction passage to maintain the centered lens position, and further closes the mold. Sometimes, the lens is fixed by the fixed core and the movable core urged by the elastic member, and the centering position of the lens does not change due to the resin flowing into the cavity.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a specific embodiment will be described.
[0011]
(Embodiment 1)
1 to 7 show a first embodiment, FIG. 1 is a longitudinal sectional view of a lens barrel integral molding die, FIG. 2 is an explanatory view of a main part of a molding die in a state where a mold is opened and a sleeve is pushed out, and FIG. Is an explanatory view of a state in which the lens is inserted into the sleeve, FIG. 4 is an explanatory view of a state in which the lens is mounted on the movable core, and FIG. 5 is a state in which the sleeve is retracted and the lens is held on the movable core. FIG. 6 is an explanatory view of a state in which a lens is fixed by a fixed core and a movable core by closing a mold, and FIG. 7 is an explanatory view of a state in which a mold is opened after molding and a molded product is extruded from a cavity. It is.
[0012]
In FIG. 1, a lens frame integral molding die 51 is one of the classes of a vertical injection molding die, and includes a fixed die 52 disposed above and a movable die 53 disposed below. The fixed mold 52 is fixed to a molding machine (not shown), and the movable mold 53 moves up and down, thereby closing and opening the mold. The parting line 6 indicates a surface where the fixed mold 52 and the movable mold 53 come into contact with each other. The outside of the fixed mold 52 is composed of the fixed mold plate 1, the slide member 21 and the fixed mounting plate 22, and the slide member 21 and the fixed mold plate 1 are integrated with the guide posts 23 implanted on the fixed mounting plate 22. ing. At the center of the fixed mold plate 1, a fixed core 2 in contact with a lens 7 is fitted by being urged downward by a coil spring 4 as an elastic member at a position facing a movable core 9 described later. The distal end 2a of the fixed core 2 is formed in a bell-clamped sharp annular shape, and abuts on the upper surface of the lens 7, and the annular distal end 2a is a cavity for forming a projection of a lens frame holding the lens 7. 13.
[0013]
A fixed abutment plate 3 having a runner 3a and a part 3b of a pin gate is disposed in the upper center of the fixed mold plate 1. A space 5 is formed between the fixed core 2 and the fixed abutment plate 3 so that the fixed core 2 can retreat when the lens thickness is increased when the mold closing is completed. A pin gate 1a is formed in the fixed mold plate 1 so as to be continuous with a part 3b of the pin gate of the fixed abutment plate 3, and communicates with the cavity 13. Further, a sprue bush 24 having a sprue 24 a is fixed to the slide member 21 and the fixed mounting plate 22, and the sprue 24 a communicates with the runner 3 a of the fixed abutment plate 3.
[0014]
The outside of the movable mold 53 includes a movable mold plate 8, two spacer blocks 25, and a movable mounting plate 12, and is fixed to each other by bolts (not shown). A guide bush 27 into which the guide post 23 implanted in the fixed mounting plate 22 fits is buried in the movable mold plate 8. When the mold is closed, the guide post 23 and the guide bush 27 fit together to fix the guide bush 27. The mold 52 and the movable mold 53 are positioned. In the center of the movable mold 53, the movable core 9 is attached to the movable mounting plate 12 by bolts 29 via the core mounting plate 26. Like the fixed core 2, the tip 9 a of the movable core 9 is formed in a bell-clamped sharp annular shape, abuts against the lower surface of the lens 7, and the annular tip 9 a is a mirror holding the lens 7. It constitutes a part of the cavity 13 for forming the projection of the frame. A suction passage 14 is formed in the center of the movable core 9 and the movable mounting plate 12 corresponding to the center, and the suction passage 14 communicates with an external suction device 15.
[0015]
The outer diameter of the movable core 9 is finished to be substantially the same as the outer circumference of the lens 7, and a sleeve 10 as an annular member is fitted to this outer diameter so as to be movable up and down. The sleeve 10 is sandwiched between two extrusion plates 11, and is moved upward by an extrusion bar 16 of a molding machine (not shown) inserted through the movable mounting plate 12 and the core mounting plate 26. This is performed by pushing up the plate 11, and the downward retreat is performed by the elastic force of the coil spring 17 mounted around the guide pin 28 that is sandwiched by the pushing plate 11 and slides inside the movable mold plate 8. . At the upper center of the movable mold plate 8, a main part of a cavity 13 for forming the outer peripheral shape of the lens frame is formed. A cavity 13 is configured by the fixed mold plate 1, the fixed core 2, the movable mold plate 8, the movable core 9, and the sleeve 10.
[0016]
Next, a lens frame integral molding method using the lens lens frame integral molding die 51 having the above configuration will be described. In FIG. 1, when the lens frame integral molding die 51 is opened and the extrusion plate 11 is advanced by the extrusion bar 16, the tip of the sleeve 10 is flush with the parting line 6, as shown in FIG. ing. Next, as shown in FIG. 3, the outer periphery of the lens 7 is inserted into the sleeve 10 by using a suction pad or the like (not shown). At this time, since the outer periphery of the lens 7 is centered on the optical axis by centering or the like, the cavity 13 is inserted into the inner diameter of the sleeve 10 having a diameter slightly larger than the outer periphery of the lens 7. The central axis of the inner peripheral wall 13a for molding the lens barrel outer periphery 16a of the molded article 16 (see FIG. 7) coincides with the optical axis of the lens 7. When the lens 7 is placed on the tip of the movable core 9 while maintaining this state, the state shown in FIG. 4 is obtained.
[0017]
Next, in FIG. 1, when the lens 7 is sucked by the suction device 15 through the movable core 9 and the suction passage 14 provided in the movable mounting plate 12, the lens 7 is attracted to the movable core 9. When the pushing bar 16 is retracted, the pushing plate 11 is retracted by the elastic force of the coil spring 17, and the sleeve 10 is also retracted at the same time, and the state shown in FIG. 5 is obtained. Since the lens 7 is attracted to the movable core 9, the position does not change even if the sleeve 10 is retracted. Further, as shown in FIG. 1, the movable mold 53 moves forward, contacts the fixed mold 52 at the parting line 6, and is integrated. At this time, as shown in FIG. 6, the lens 7 is held between the movable core 9 and the fixed core 2 by the elastic force of the coil spring 4. The resilience of the coil spring 4 is set to such an amount that the horizontal displacement does not occur and the lens 7 is not scratched or cracked even when receiving the injection pressure of the resin at the time of molding. After closing the mold, the suction device 15 (see FIG. 1) is stopped, and the suction force of the lens 7 is not generated.
[0018]
In the state shown in FIG. 6, a cavity 13 is formed by the fixed mold plate 1, the fixed core 2, the movable mold plate 8, the movable core 9, and the sleeve 10. This cavity 13 is injected and filled with a molten resin, and after cooling and solidification, the mold is opened. As shown in FIG. 7, a lens frame is formed integrally with the lens frame on the outer periphery of the lens 7. The molded article 16 is in a state where the sleeve 10 is pushed out of the cavity 13. When the molded product 16 is discharged by a robot hand or the like (not shown), the state shown in FIG. 2 is obtained, and the following operation is repeatedly performed.
[0019]
According to the present embodiment, the lens can be centered by the sleeve, and during the molding, the fixed core and the movable core do not cause horizontal displacement even when receiving the injection pressure, and the lens is not scratched. The lens is sandwiched with the amount of force that does not cause cracks, so the centering mechanism of the lens is simplified, the centering of the lens and the lens frame can be easily done, and the resin storage part of the lens housing wall of the lens frame is missing No lensing occurs, and a lens frame integral molded product with good centering accuracy can be obtained.
[0020]
In the present embodiment, a coil spring is used for holding the lens and returning the sleeve, but another elastic member such as urethane rubber may be used as long as an appropriate force and an expansion / contraction distance can be obtained. Although the lens 7 has the shape of a biconcave lens, the present embodiment can be applied to a biconvex lens and a meniscus lens.
[0021]
【The invention's effect】
According to the first or second aspect of the present invention, the annular member is raised in the center axis direction of the lens, and the center is centered by inserting the outer periphery of the lens with the inner diameter thereof, and the movable core has a bell clamp shape. The lens is placed on the tip, and when closing the mold, the lens is sandwiched and fixed between the fixed core and the bell-clamp-shaped tip, so the centering mechanism of the lens is simplified, and the lens In addition, it is possible to obtain a molded lens-lens frame integral product in which the centering of the lens-lens frame can be easily performed, and the resin storage wall of the lens frame does not have a missing portion of resin.
According to the invention according to claim 2, in addition to the above effects, the lens mounted on the movable core is suctioned by the suction device via the suction passage to maintain the centered lens position, and the mold is further formed. When the lens is closed, the lens is fixed by the fixed core and the movable core urged by the elastic member, and the centering position of the lens is not changed by the inflow of resin into the cavity, so that the centering accuracy is good. A lens barrel integral molded product can be obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a lens frame integral molding die according to a first embodiment.
FIG. 2 is an explanatory view of a main part of a molding die in a state where a mold opening sleeve of the first embodiment is pushed out.
FIG. 3 is an explanatory diagram illustrating a state where a lens is inserted into the sleeve according to the first embodiment;
FIG. 4 is an explanatory diagram of a state where the lens according to the first embodiment is mounted on a movable core.
FIG. 5 is an explanatory diagram of a state in which the sleeve of the first embodiment is retracted and the lens is held on the movable core.
FIG. 6 is an explanatory diagram of a state in which the lens is fixed by a fixed core and a movable core by closing the mold according to the first embodiment;
FIG. 7 is an explanatory view showing a state in which the mold is opened after molding and the molded product is pushed out of the cavity according to the first embodiment.
[Explanation of symbols]
2 Fixed core 7 Lens 9 Movable core 10 Sleeve

Claims (2)

In a lens frame integral molding die in which a lens is inserted, and a resin is filled in an outer peripheral portion of the lens to form a lens frame,
A movable core having an outer diameter substantially the same as the outer circumference of the lens and having a bell-clamped tip and a fixed core disposed opposite to the movable core and having a bell-clamped tip; An annular member fitted to the child and capable of moving back and forth in a direction parallel to the central axis of the lens. The fixed core is urged by an elastic member in the direction of the movable core, and a suction passage communicating with a suction device is formed at the center of the movable core. Item 2. A lens frame integral molding die according to Item 1.

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