JPS6242815A - Plastic lens mold - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Field of application of the invention] 1゜ The present invention is a high-precision camera used in video cameras and the like.

Particularly related to molds for molding plastic lenses.

Plastic suitable for preventing the occurrence of burrs.

Related to lens molding molds.

[Background of the invention] 211
Conventional molds for molding plastic lenses.

resin as described in JP-A-58-94456.

High-precision lenses were obtained by pressurizing the material. However, the cavity that forms the lens shape.

The lens surface is mirror-finished.

It is composed of a large number of members such as a holding member.

Regarding the cracks that occur in the gaps between the members and in the gaps between the sliding parts due to pressurization of the resin.

It wasn't taken into consideration.

FIGS. 5 and 4 are sectional views of essential parts of a conventional mold for molding 1° plastic lenses.

Ru. The movable inserting piece 21 is fixed within the movable holding member 25 by a screw 26°, and the movable holding member 25 is slidably inserted into the movable sleeve 25 in the direction of the rotation center axis 52 of the lens surface. Also fixed type.

The piece 22 is fixed in a fixed holding member 24 with a screw 27.

has been done. In the conventional mold structure, there is no entry piece.

The outer periphery of the surface was made of a cylindrical surface, so it was a movable figure.

The distance between the piece 21 and the movable holding member 25 and between the fixed inserting piece 22 and the fixed holding member 24 is at least 10 μm due to the necessity of assembling the inserting piece and the holding member.

A gap of approximately 54.55 mm was created. Especially the lens.

In the case of Irikoma whose surface has a convex shape, the lens surface is a mirror.

During surface processing, a plane perpendicular to the rotation center axis of the lens surface that is directly connected to this is added to the outer periphery of the lens surface.
However, since it was difficult, the gap 54.55 was created. Moreover, between the movable holding member 25 and the movable sleeve 25,
A gap 55 of at least 10 μm or more required for sliding was created. As a result, the cab.

Tee 1 is filled with high temperature, highly fluid resin under high pressure.

In order to fill the gap, resin flows into the gaps 55, 54, and 55.

It gave rise to Paris. In addition, even if the lens surface has a concave shape, the movable insert piece 28 can be used.

A gap 56 is required between the movable sleeve 50 for sliding movement, and the same gap occurs as described above. ,.

These paris are defective as products and products.

After releasing from the mold, deburring is required. Also,.

This material digs into the sliding part and causes seizure of the sliding part.

It was the cause of this.

[Object of the invention] 2゜ The object of the present invention is to eliminate the drawbacks of the above-mentioned prior art.

For gaps and pressure between the members that make up the cavity.

A structure that prevents cracks from occurring due to gaps between sliding parts.

We provide molds for molding plastic lenses.

There is a particular thing.

[Summary of the invention]

In order to achieve the above object, the present invention provides an input piece and its holding member that are directly connected to the cavity.

The contact surface and the sliding surface for pressurization are the cavity side.

The member is made of a conical surface that opens in the opposite direction.

Eliminate or reduce gaps for sliding movement.

This prevents burrs from forming in the gap.

It was designed so that it could be done.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a plastic lens molding die according to the present invention. 1° is the cavity that forms the lens shape, and 2 is movable.

The frame, 5 is a fixed frame, 4 is a movable piece, and 5 is a fixed frame.

・　5　・ 6 is a movable holding member, and 7 is a fixed holding member.

8 is a movable sleeve, 9 is a hydraulic cylinder, and 10 is Z.

11 is an extrusion plate, and 12 is a molding machine (not shown).

The attached ejector rod 15 is the nozzle of the molding machine.

14 is the sprue, and 16.18 is the fixing screw.

This is an indication.

Here, the outer peripheral surface of the movable insert piece 4 and the movable holding member.

The inner circumferential surfaces of the movable retaining members 6 have the same taper toward the cavity 1, or the inner circumferential surface of the movable holding member 6 has the same taper as the outer circumferential surface of the movable inserting piece 4.

It is slightly thicker, 1/ in this example. Taper of.

It is machined with a conical surface, and is secured by screw 16.

It is pulled and fixed in the opposite direction to Bitty 1. .

Therefore, the outer peripheral surface of the movable insert piece 4 and the movable holding portion.

There is almost no gap in the contact surface 15 with the inner peripheral surface of the material 6.

It won't happen. Also, the inner peripheral surface of the movable holding member 6.

The taper is larger than the taper of the outer peripheral surface of the movable inserting piece 4.

The reason for this is that if the tapers of both are made equal.

Due to machining accuracy, the outer circumferential surface of movable insert piece 4 is slightly better.

2° only near the lens surface of movable entry piece 4
4.

By contacting the movable holding member 6, the lens is brought close to the surface.

This is to prevent the lens surface from deforming due to force acting only on the vicinity, and even in this case, the conventional circle.

than the contact surface 150 gap when configured with a cylindrical surface.

becomes smaller. Therefore, the nozzle 15 of the molding machine.

Sprue resin with good fluidity melted at high temperature.

14 and filled into the cavity 1 under high pressure.

Sometimes, there is almost no gap on the contact surface 15, so

No damage occurred. As described above, the movable entering pieces 4.

A cavity is formed on the outer peripheral surface and the inner peripheral surface of the movable holding member 6].

Created by creating a conical surface that opens in one direction from the tee.

Mold disease does not occur on the molded product and is easy to assemble.

It can be made into a structure. Fixed entering piece 5 and fixed holding.

Member 7 should also have the same structure as above.

Accordingly, it is possible to prevent and eliminate cracks that have conventionally occurred on the contact surface 17. Also, the above mold structure was adopted.

Therefore, when assembling the mold, the lens surface of the insert piece.

The center axis of rotation can always be easily fixed at the same position.

There was also the advantage that

FIG. 2 shows the sliding movement of the movable insert piece 19 and the movable sleeve 21 for pressurizing and shaping the resin in the cavity 1.

The surface 58 is a beak with a conical surface open in one direction of the cavity.

FIG. .

The same parts as in FIG. 1 are given the same reference numerals. .

In insert piece-1, which has a concave lens surface like the fixed insert piece 20, a plane perpendicular to the 5 axes of rotation of the lens surface can be machined on the outer periphery of the lens surface, so it is possible to form a contact surface that directly connects to the cavity 1°. It does not have and causes Paris.

There's nothing wrong. However, in order to obtain a high-precision lens.

In the conventional metal 1° mold that pressurizes and shapes the resin in the cavity 1, a gap between the sliding surfaces is required for the pressurization.

There was a crack on this sliding surface. Therefore.

In the mold of the present invention, this sliding surface is formed of a conical surface that is open in the direction of 1° of the cavity, thereby achieving the above-mentioned condition.

A structure that prevents cracks that occur in the gaps between sliding surfaces.

Closed. In this embodiment, a movable entering piece 19 and a movable pickpocket.

- The sliding surface 58 with the pipe 21 is opened in the direction of the cavity 1.

It was constructed with a conical surface with a taper of 1150 mm. Cavite.

Highly fluid resin melted at high temperature in A1.

When filling with pressure, the movable entry piece 19 moves in the opposite direction to the cavity 1 due to the 2° resin pressure inside the cavity 1.

When pressed, the movable entry piece 19 is on the opposite side of the cavity 1.

As a result, the moving piece 19 moves backward.

The outer peripheral surface of the movable sleeve 21 had a taper.

It contacts the inner circumferential surface and eliminates the gap between the sliding surface 580. .

Next, the movable entry piece 19 is carried by the hydraulic cylinder 9.

Move the tree forward in the cavity 1 direction and move the tree inside cavity 1.

When pressurizing fat into shape, the temperature of the resin is controlled by the mold.

The fluidity of the resin increases because it has been cooled to some extent.

If the gap force of 5° caused by the advance of the movable inserting piece 19 is sufficiently small, no breakage will occur. Real truth.

In the example, the resin in the cavity 1 is pressurized.

The amount of advance of the movable inserting piece 19 during shaping is approximately 50 μm.

If the taper of the sliding surface 58 is 115o, then the sliding.

Since the gap created on the sliding surface 58 is sufficiently small, approximately 1 μm, no cracks will occur on the 1° sliding surface 58. As stated above.

Like, a circle with the sliding surface 5 days open in one direction of the cavity.

Sliding due to the mold structure consisting of conical surfaces.

It is possible to prevent cracks from occurring on the surface 38. Also,.

The movable insert piece 19 part is composed of the insert piece and its holding member, and the 9°
7. In this case, the same as the embodiment described using FIG.

It is a good idea to configure the contact surface between the two with a conical surface.

It is effective in preventing the occurrence of stains.

〔Effect of the invention〕

As explained above, the insert piece is directly connected to the cavity that forms the second shape of the plastic lens.

The length of the contact surface between the outer peripheral surface of the holding member and the inner peripheral surface of the holding member.

Sliding motion to pressurize and shape the resin inside the cavity.

The surface consists of a conical surface that opens toward the cavity.

Conventionally, this occurs on the contact surfaces and sliding surfaces.

This prevents flaking and requires deburring processing.

No plastic lenses are obtained, molded by Paris.

can prevent damage.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views of an i-1 mold showing an embodiment of the present invention, and FIGS. 5 and 4 are conventional molds. It is a sectional view of the main part of a mold. 1... Cavity, 2... Movable frame, 5... Fixed frame. Body, 4...Movable entering pieces, 5...Fixed entering pieces, 6...Movable holding pieces. Holding member, 7... Fixed holding member, 8... Movable sleeve, 11° 8 ゛9... Hydraulic cylinder, 15.17... Contact surface, 58
...Sliding surface. Figure 1 Figure 2

Claims (1)

[Claims] 1. A fixed insert piece and a movable insert piece, each having a mirror-polished surface forming a lens surface, are arranged in a fixed frame or a movable frame, respectively, directly or fixed to a holding member so that the lens surfaces face each other. In the mold for molding a plastic lens, the contact surface between the input piece and the frame, or between the input piece and the holding member, which is directly connected to the cavity that forms the shape of the plastic lens, is formed with a conical surface that opens toward the cavity. A plastic lens mold that features: