JPH0261891B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a manufacturing method for simultaneously manufacturing a lens barrel unit, particularly a lens barrel unit in which a plurality of helicoid tubes are screwed together, by molding.

(Prior Art to the Invention) One of the techniques of the present invention is that in a lens barrel unit consisting of a combination of a plurality of barrels, for example, a male barrel and a female barrel, when one barrel is made, the other barrel is This relates to a molding technique used as a mold member for molding. Japanese Patent Publication No. 4768/1986 is a useful document regarding this technology.

Another technique of the present invention relates to a technique of removing an intermediate member after forming an intermediate member when molding a lens barrel unit; There is a public gazette No. 57-8508.

(Problems with the prior art) In the prior art described above, in the case of a technique in which the other cylinder made in advance is used as a mold for molding one cylinder, the male cylinder is used as the mold and the female cylinder is used as the mold. When molded with resin, the shrinkage of the male cylinder as it cools causes the helicoid threaded part of the female cylinder to shrink, eliminating the gap between the helicoid threaded parts of the male cylinder and female cylinder, and causing the threaded part of the male cylinder and female cylinder to tighten. A biting phenomenon occurs, making it difficult to obtain smooth relative rotation. It is very difficult to determine the dimensions and materials of each part of the cylindrical member, as well as the cooling temperature control and mold pressure control, in order to set the gap caused by this shrinkage to an optimal screwed state.

(Object of the invention) The object of the invention is to fit or screw together a plurality of lens barrels,
In a method of manufacturing a lens barrel unit made by using one of the rotating bodies that screw or slide together as a mold and molding another rotating body, the gap between the fitting or screwing parts is filled with the fitting or screwing part. The object of the present invention is to provide a manufacturing method that can obtain preferred dimensions for.

(Description of Embodiments) FIG. 1 shows a lens barrel incorporating a double helicoid barrel unit made according to the present invention.
In the figure, 1 is a fixed cylinder, 2 is a mount member screwed to the fixed cylinder 1, and 4 is a double helicoid cylinder with helicoids formed on the inner and outer peripheries.
A is screwed into the fixed cylinder, and the inner helicoid 4B is screwed into the helicoid 6A of the lens holding cylinder 6, respectively. A linear keyway 6B is formed on the outer periphery of the lens holding cylinder 6, and a key member 2A fixed to the mount member 2 is engaged with the keyway 6B. L ₁ to _{L 6} are focus lenses held in the lens holding cylinder 6. 8
is an exterior ring fixed to the tip of the lens holding tube 6. 10
is a distance ring fixed to the tip of the double helicoid cylinder 4 with a screw 12. When the lens barrel configured as described above rotates the distance ring 10 around the optical axis, the lens barrel 6 rotates together with the double helicoid barrel.
The focus adjustment is performed by moving straight in a direction parallel to the optical axis 0 ₁ -0 ₂ depending on the relationship between the keyway and the key.

2 to 6 show a double helicoid tube unit consisting of a fixed tube 1, a lens holding tube 6, and a double helicoid tube 4 of the lens barrel shown in FIG.
An example will be shown in which the fixed tube 1 and the lens holding tube 6 are manufactured simultaneously using one mold.

Of the lens unit, the double helicoid cylinder 4 is made in advance from a metal material or a resin material, as shown in FIG. One end of the helicoid cylinder 4 is provided with a plurality of screw holes 4C for the screw 12 and a plurality of holding holes 4d, which will be described later. The helicoid tube 4 made in advance is held in the mold shown in FIG. 3, but before being held in the mold, the outer helicoid portion 4A of the helicoid tube 4 is removed as shown in FIGS. 4A and 4B.
A soluble solvent 14 is applied to the surface. FIG. 4B shows a partial cross section of the helicoid portion 4A with the solvent 14 applied on its outer periphery.

The soluble solvent 14 is coated or sprayed with a solution of a neutral polysaccharide in which maltotriose is regularly bonded with α-1.6, and the film is dried to a constant film thickness. The film thickness is set so that the helicoid coupling between the helicoid cylinder 4 and the lens holding cylinder 6 can be smoothly performed.

The helicoid tube 4 covered with the soluble membrane 14 is the third
Hold in the mold shown in the figure. In Figure 3, 16
23 and 18 are fixed side mold members, 20 is a movable side 23, 22 is a mold member that holds the helicoid cylinder 4, 24 is a movable side mold member, and 26 is a mold member for the hissing hole of the fixed cylinder, respectively. show.

The helicoid tube 4 is held in the mold by a holding pin 22A extending from the holding mold member 22 and a holding pin 18A extending from the stationary mold member 18.

Inside and outside of the helicoid tube 4 in the mold are the helicoid tube 4 and mold members 16, 18, 2.
A hollow ring-shaped gap 28 is formed by the mold members 18, 22, 24, and 26, and a hollow ring-shaped gap 30 is formed by the mold members 18, 22, 24, and 26. The stationary mold member 18 is provided with a gate 18a that communicates with the void 28, and a gate 18a that communicates with the void 30.
8b are provided respectively. Molten resin material is injected into each of the gaps 28 and 3 from an injection unit (not shown) connected to the mold shown in FIG.
Inject into 0.

A molten resin material is filled into each of the voids 28 and 30 to fill the voids and produce a molded body. Thereafter, the mold is cooled to cool the resin material. After cooling the molten resin, move the mold member on the movable side to take out the helicoid cylinder 4, the fixed cylinder 1 and the lens holding cylinder 6 as molded bodies inside and outside the helicoid cylinder 4 from the mold, as shown in Figure 5. .

In the mold shown in FIG. 3, the inner peripheral side of the cavity 30 is filled with a molding resin via a soluble film 14 covering the helicoid portion 4A of the helicoid cylinder 4.

FIG. 5A shows a partial cross section of the helicoid tube 4, the lens holding tube 6, and the fixed tube 1.

After taking out the molded body shown in Figure 5 from the mold,
The molded body is immersed in water to dissolve and remove the maltotriose 14 in the soluble film. FIG. 6B shows the cross section after dissolution and removal.

By removing the soluble film 14, a clearance 32 is formed between the helicoid tube 4 and the fixed tube 1. Further, between the helicoid cylinder 1 and the lens holding cylinder 6, the lens holding cylinder 6 contracts in the radial direction due to the cooling contraction effect of the lens holding cylinder 6, and a clearance 34 is formed between the helicoid cylinder 1 and the helicoid cylinder.

These clearances 32 and 34 enable the inner lens holding tube 6 and the outer fixed tube 1 to rotate smoothly with the helicoid tube 4 in between.

The double helicoid tube unit consisting of the helicoid tube 4, the fixed tube 1, and the lens holding tube 6 explained with reference to FIGS.
The clearance 32 can be adjusted appropriately by selecting the film thickness of
can be determined. Therefore, even when the double helicoid tube unit is assembled into the lens barrel shown in the first figure, the double helicoid tube 4 rotates smoothly due to the rotation of the operating ring 10. The embodiments shown in FIGS. 1 to 6A and B show examples in which the helicoid tube 4 is short, but as shown in FIG.
Even when using a tube 40 that is integrally composed of a double fitting portion 40A for fitting a lens barrel and a bayonet portion 40B such as a bayonet tube for attaching a lens barrel to a camera as a fixed tube, the fixed tube 40 can be prepared in advance. It can be made by holding it in the mold shown in FIG. 8 in the same manner as in FIG. 3.

As described above, according to the present invention, the inner cylinder and the outer cylinder are simultaneously molded on the inside and outside of the intermediate cylinder made in advance using a single mold, and the outer cylinder and the outer cylinder due to shrinkage due to the molding process are This solves the problem of lack of rotational smoothness due to contraction and tightening that occurs between the intermediate cylinders, and allows molding and assembly of at least three parts in one process, reducing the number of molding dies. It enables a significant reduction in manufacturing costs by shortening the work process.

In particular, according to the present invention, by adopting a configuration in which the outer periphery of the intermediate cylinder (helicoid cylinder 4) used as a mold member is coated with the soluble film 14, the clearance between the intermediate cylinder and the outer cylinder can be adjusted, and helicoidal coupling can be achieved. The rotation of the rotating part can be guaranteed, and the effort of post-processing of the actual product due to the unsmoothness of the rotating part can be saved.

[Brief explanation of the drawing]

FIG. 1 shows a lens barrel incorporating a double helicoid barrel unit manufactured by the manufacturing method according to the present invention. 2 to 6A and 6B are diagrams explaining the manufacturing process of the double helicoid barrel unit, and FIG. 2 is a sectional view of a helicoid barrel as an intermediate barrel prepared in advance. Figure 3 is a sectional view of the main parts of the mold.
FIG. 4A is a cross-sectional view of the helicoid cylinder 4 coated with a soluble film. FIG. 4B is an enlarged partial view of FIG. 4A. FIG. 5 is a cross-sectional view of a molded article formed by the mold shown in FIG. 3. FIG. 6A is a partial cross-sectional view of the double helicoid lens barrel unit with the soluble film remaining. FIG. 6B is a partial cross-sectional view of the double helicoid lens barrel unit after the soluble film has been removed. 7th
FIG. 8 is a diagram showing another embodiment. 1... Fixed tube (outer tube), 4... Helicoid tube (intermediate tube), 6... Lens holding tube (inner tube), 14...
...Soluble membrane.

Claims (1)

[Scope of Claims] 1. A double helicoid cylinder made of a metal material or a resin material and having helicoid threaded parts on the inner and outer peripheries, and a soluble film coated on the helicoid threaded parts on the outer periphery, is placed in a mold. Holding the double helicoid tube, molding voids are provided inside and outside of the helicoid screw portions on the inner and outer peripheries of the double helicoid tube, and resin is injected into the void of the molding mold to form molding holes inside and outside the double helicoid tube. A molded body is made, and then the double helicoid tube and the molded body are taken out, the inner molded body and the outer molded body of the double helicoid tube are separated, and the outer helicoid threaded portion of the double helicoid tube and the outer molded body are separated. The soluble film between the double helicoid tubes is removed, and the inner cylinder made of the inner molded body is screwed into the inner peripheral helicoid threaded part of the double helicoid cylinder, and the outer cylinder made of the outer molded body is screwed into the outer peripheral helicoid threaded part. A method for manufacturing a double helicoid lens barrel unit characterized by: