JPS61266214A - Manufacture of lense tube unit - Google Patents

Abstract

PURPOSE:To obtain the lense tube unit, capable of regulating a clearance between a male tube and a female tube arbitrarily and setting the magnitude of rotating torque arbitrarily, by a method wherein the effective engaging section of the male tube between the female tube to be molded is coated by a film consisting of a soluble material and the female tube is formed utilizing the coated male tube as a male mold. CONSTITUTION:The male tube 1, consisting of metallic material (stainless steel, aluminum alloy or the like) or a resin material (polycarbonate series), is dipped into solution prepared by melting the soluble material. Next, the male tube 1, whose soluble film 2 is cured already, is mounted in a casting mold to mold the female tube 3. The female tube 3 is formed with a screw transferred from the soluble film. The soluble film 2 is molten and removed from the molded form, whose molding is finished and taken out of the mold, whereby the tube unit having a clearance S may be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Description of the field to which the invention pertains The present invention relates to a method of manufacturing a pair of lens barrel units such as a male barrel and a female barrel.

(2) Explanation of conventional technology In unit barrels, which are a pair of male and female barrels used in camera lens barrels, when the male and female barrels are repeatedly moved relative to each other, optical precision and appropriate operation cannot be improved. Sensual precision in terms of weight is required. In order to satisfy this requirement, it is necessary to form a minute gap between the male cylinder and the female cylinder.

Conventionally, when manufacturing a unit cylinder consisting of a male cylinder and a female cylinder by molding, the method of forming this gap was to utilize the molding shrinkage of resin as disclosed in Japanese Patent Publication No. 60-4768. It is being To do this, a female cylinder (outer cylinder) was created in advance, then this was attached and held in a mold for a male cylinder (inner cylinder), and then resin was injected to form the male cylinder, resulting in a pair of male and female cylinders. The purpose is to manufacture unit tubes. In this case, the male cylinder undergoes molding shrinkage, thereby forming a minute gap between the male cylinder and the female cylinder. However, such a conventional example has the following drawbacks.

First, as long as we try to create gaps using molding shrinkage,
The process of molding a male based on a female cannot be avoided. In other words, the male is made of resin material, and metal materials cannot be used for the male. For this reason, it is difficult to apply this method to a male member that requires strength from the member itself, such as a thin-walled, long-tube male shown in FIG. 1, or a male with a thin diameter and long axis shown in FIG. 9.

Second, if you are trying to make a female by resin molding, please refer to Figure 2 1.
It is necessary to undercut the inner diameter of the knife as shown in 2a. As is known in the art, this undercutting process requires the provision of a mechanism that rotates the mold member 12 to remove it or mechanically contracts it in the central axis direction and removes it.

These mechanisms complicate the structure of the mold, making mold production labor-intensive and expensive.

Thirdly, the undercut treatment may be limited to treatment by shrinkage of the mold member. This is the case when the undercut on the inner diameter of the female cylinder does not have a screw-like shape, but has grooves that are axially symmetrical about the six axes in the cylinder. In this case, the inner diameter of the female cylinder must be dimensioned to allow for mold space for providing a complicated mechanism for contraction. For this reason, there is a limit to reducing the inner diameter of the knife cylinder due to the undercut, and there is a regulatory framework for product design. Furthermore,
In a camera lens barrel that has a male lens barrel that holds a lens optical system, etc., and a female lens barrel that is screwed into the male lens barrel,
A cylindrical part made of a meltable or crushable resin material is molded and welded to one end of the female lens barrel made of a metal or resin material, and then the female lens barrel with the cylindrical part molded and welded is attached to the female lens barrel made of a metal or resin material. It is used together with the cylindrical part as a molding jig, and the resin material of the male side lens barrel is injected into the cylindrical part and the inside of the female side lens barrel to form the male side lens barrel, and then the cylindrical part is melted. JP-A-57-8508 discloses a lens barrel characterized in that the female lens barrel and the male lens barrel are screwed together after removal by crushing or the like.

The lens barrel according to the above-mentioned publication includes a step of molding the cylindrical portion from a meltable or pulverizable resin material, making the mold structure and the molding material structure complicated.

(3) Purpose of the Invention An object of the present invention is to provide a method for forming a gap between a male tube and a female tube without using molding shrinkage of resin.

In particular, the object of the present invention is to coat the outer periphery of the male cylinder, especially the effective fitting part with the female cylinder to be molded, with a film made of a soluble material, and mold the female cylinder onto the coated male cylinder. It is an object of the present invention to provide a method for manufacturing a lens barrel unit consisting of a female barrel.

Furthermore, the present invention provides a method for manufacturing a lens barrel unit in which the clearance between the male barrel and the female barrel can be arbitrarily adjusted and the magnitude of the rotational torque can be arbitrarily set.

(4) Explanation of the structure and operation of the invention 3 to 6 show embodiments of the present invention.

FIG. 3 is a diagram showing a male cylinder 1 having a thread on its outer periphery, and a soluble film 2, which will be described later, formed on the outer periphery.

FIG. 4 shows a mold structure for molding a female cylinder based on a male cylinder having a soluble membrane on the outer periphery.

Reference numeral 1 denotes a male cylinder held in a mold, and has a soluble film 2 on its outer periphery. 3a is a cavity for forming a female cylinder, and is formed by mold member 1, 10, 11, 14, and soluble film 2. 13a and 13b are runners for injecting resin into the cavity 3a.

FIG. 5 is a view of the female cylinder taken out from the mold after completion of molding. A male cylinder 1 and a female cylinder 3 are integrated with a soluble membrane 2 in between.

FIG. 6 shows the completed unit cylinder, in which the soluble film has been removed and a minute gap S has been formed between the male cylinder 1 and the female cylinder 3.

Next, the manufacturing process in this example will be described. A male tube 1 made of pre-fabricated metal material (e.g. stainless steel, aluminum alloy, etc.) or resin material (polycarbonate)
is immersed in a solution containing a soluble material. In this case, make sure that only the threaded part on the outer periphery of the male cylinder is immersed in the solution. Rotate the male tube so that the film coats the entire circumference of the screw, then slowly pick up the male tube. Next, this male cylinder is dried with hot air to solidify the thin film of soluble material attached to the outer circumference of the screw. Figure 3 shows the result of the above steps.

The film thickness can be controlled by the viscosity of the solution in which the soluble material is dissolved and the conditions for taking up the solution from the male cylinder 1. Note that the film forming method is not limited to immersion alone.

Next, the male tube 1 with the solidified soluble film is placed in a mold as shown in FIG. 4, and the female tube 3 is formed. The female cylinder 3 has a screw transferred from the soluble film formed on its inner diameter. In this case, since the female cylinder is molded based on the male cylinder, there is no need for an undercut processing mechanism for the internal diameter thread of the female cylinder, which was conventionally necessary, in the female cylinder mold.

The molded product taken out from the mold after the above molding is completed is shown in FIG.

Next, the molded body shown in FIG. 5 is subjected to a predetermined treatment to dissolve and remove the soluble film 2, thereby obtaining a unit cylinder in which the gap S shown in FIG. 6 is formed.

As an example of the material used for the soluble membrane, a neutral polysaccharide in which water-soluble maltotriose is regularly α-1,6 may be used.

After being formed as a structural member, this material has heat resistance and strength suitable for injection molding, and also has water-soluble properties.

The removal of the membrane 2 of the molded bodies shown in FIG. 5 is carried out by immersing the molded bodies 1, 2, and 3 in water and stirring.

In the lens barrel of this example, in order to ensure screw precision,
Also, set the gap between the male tube and the female tube to, for example, 1/OO~
Since it is necessary to keep the dimensions to a microscopic range of about 10/100 mm, the thickness of the film itself must also be miniaturized. Fortunately, the reason for this is that since the film is thin and the amount is very small, it can be dissolved and removed in a short time.

On the other hand, the gap amount S shown in FIG. 6 can be appropriately set depending on the film thickness of the soluble film, the selection of resin material for forming the female tube 3, and the molding conditions. It is possible to minimize the play when repeatedly moving relative to each other, and to fully satisfy sensory accuracy such as optical accuracy and appropriate operating weight.

This embodiment is not limited to the screw unit cylinder, but the seventh
The present invention can be easily applied to an axisymmetric fitting unit tube including the part shown in FIG. 8, or a unit consisting of a shaft and a bearing as shown in FIG.

According to this embodiment, the gap between the male tube and the female tube can be formed without relying on molding shrinkage of the resin. (1) Even if the female tube is molded based on the male tube, the engagement accuracy is A unit tube that satisfies sensory accuracy and sensory accuracy can be obtained.

(2) The male tube can be made of resin or metal. As a result, the range of strength selection for the male cylinder is widened, and it can be used as a unit cylinder in a wide range of applications.

(3) Even when the female cylinder mold has an undercut shape such as a screw on the inner diameter of the female cylinder, there is no need for any undercut processing mechanism, and the mold can be manufactured at low cost.

(4) The internal diameter of the female cylinder is no longer restricted by the undercut processing mechanism of the female cylinder mold, allowing molding to be performed even with smaller dimensions, allowing for more freedom in product design than before.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a unit cylinder in which the male cylinder is a thin-walled long cylinder. Fig. 2 is a sectional view of a conventional female cylinder mold. Figs. 3 to 6 are sectional views of the present embodiment. Fig. 9 is a cross-sectional view of a unit cylinder to which this embodiment is applied. 1 is a male cylinder, 2 is a membrane 3.3α and 3β made of a soluble material, a female cylinder, S is a minute gap 3a, and a cavity 12a is an undercut shaped part u-th. [8

Claims (1)

[Claims] A male cylinder made of a metal material or a resin material with a film made of a soluble material formed on at least a portion of its outer periphery is mounted and held in a mold, resin is injected, and the film is sandwiched between the male cylinder and the male cylinder. A lens barrel unit characterized in that the female barrel is shaped as shown in FIG. Production method.