JPH0227134B2 - - Google Patents

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) Description of conventional technology In unit tubes used in camera lens barrels, which consist of a pair of male and female tubes, when the male and female tubes are repeatedly moved relative to each other, it is difficult to achieve optical accuracy and proper operation. 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 the resin, as disclosed in Japanese Patent Publication No. 60-4768. It is being To do this, a female cylinder (outer cylinder) is made in advance, and then this is attached and held in a mold for a male cylinder (inner cylinder), and then resin is injected to form the male cylinder, resulting in a pair of male and female cylinders. The purpose is to manufacture unit cylinders. In this case, the male cylinder undergoes molding shrinkage, thereby forming a minute gap between the male cylinder and the female cylinder. However, such conventional examples have the following drawbacks.

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

Second, if the knife is to be made by resin molding, it is necessary to undercut the inner diameter of the knife as shown in FIG. 12a. As is well known, this undercutting process requires the provision of a mechanism for rotating the mold member 12 or mechanically shrinking it in the direction of the central axis.

These mechanisms complicate the structure of the mold, making it difficult to manufacture the mold and resulting in an expensive mold.

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 is not shaped like a screw, but has a groove that is axially symmetrical with respect to the central axis of 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. Therefore, there is a limit to reducing the inner diameter of the female cylinder with an undercut, and there are restrictions on 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, the lens barrel may be made of a metal material or a resin material. A cylindrical part is molded and welded to one end of the female lens barrel using a meltable or crushable resin material, and then,
The female lens barrel with the cylindrical portion molded and welded is used together with the cylindrical portion as a molding jig, and the resin material of the male lens barrel is injected into the cylindrical portion and the inside of the female lens barrel to form the male side. Japanese Unexamined Patent Publication No. 1983-1999 discloses a lens barrel characterized in that a lens barrel is molded, the cylindrical portion is removed by melting or crushing, and a female lens barrel and a male lens barrel are screwed together.
It is known as Publication No.-8508.

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) Object of the invention An object of the invention is to provide a method for forming a gap between a male cylinder and a female cylinder without using molding shrinkage of resin.

In particular, the object of the present invention is to coat the outer periphery of a 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 of 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 mold members 1, 10, 11,
14 and a soluble film 2. 13a, 13
b is a runner 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 in advance of a metal material (for example, stainless steel, aluminum alloy, etc.) or a 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 is coated all around the screw, and 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 treatment 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.

Examples of materials used for the soluble film include:
Water-soluble maltotriose is regularly α-1,
A neutral polysaccharide prepared under 6 may be used. After being formed as a structural member, the material has heat resistance and strength that can withstand injection molding, and also has water-soluble properties. Film 2 of the molded body in Fig. 5
The removal is carried out by immersing the molded bodies 1, 2, and 3 in water and stirring them. In the lens barrel of this example, in order to ensure screw precision and because it is necessary to keep the gap between the male barrel and female barrel very small, for example, between 1/00 and 10/100 mm, the film is It is also necessary to reduce the thickness of the film itself. 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. It is possible to minimize the play when the cylinder is repeatedly moved relative to the cylinder, and to fully satisfy sensory accuracy such as optical accuracy and appropriate operating weight.

The present embodiment is not limited to a screw-fitting unit cylinder, but can also be applied to an axially symmetrical fitting unit cylinder including the parts shown in Figs. 7 and 8, or a unit consisting of a shaft and a bearing as shown in Fig. 9. can also be easily applied.

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. A unit tube that satisfies both sensory accuracy and sensory accuracy can be obtained.

(2) You can choose whether the male tube is made of resin material or resin material. This widens the range of strength selection for the male cylinder, allowing it to be used in a wide range of applications as a unit cylinder.

(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 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 this embodiment, and Fig. 7 Figures 9 to 9 are cross-sectional views of unit cylinders to which this embodiment is applied. 1 is a male cylinder, 2 is a membrane made of a soluble material, 3, 3
α and 3β are female cylinders, S is a minute gap, 3a is a cavity, and 12a is an undercut shaped part.

Claims (1)

[Claims] 1. A male cylinder made of a metal or 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, and resin is injected to form the film between the male cylinder and the male cylinder. A lens barrel unit characterized by forming a female barrel in a sandwiching manner, then taking it out of the mold, and dissolving and removing only the film outside the mold to form a minute gap between the male barrel and the female barrel. manufacturing method.