JPH0227133B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method for manufacturing a lens barrel unit, for example, a lens barrel unit having a male barrel and a female barrel or an intermediate barrel between the male and female barrels, and in particular, The present invention relates to an invention in which the lens barrel unit is made from a resin material using a molding technique.

More specifically, the present invention relates to a method of manufacturing a lens barrel unit in which the male tube and the female tube are integrally molded.

(Prior art to the invention) A technique for simultaneously manufacturing the male and female barrels of a lens barrel unit by molding them using a resin material was developed in the 1980s.
Publication No. 4768, JP-A-57-8508, or JP-A-57
-8509 publication is known.

(Problems with the prior art) In the case of the prior art, the female cylinder is made of a metal material or a resin material in advance, and the female cylinder is used as a molding material, and at least a part of the female threaded part of the female cylinder and a plurality of other parts are used. Form a predetermined molding space surrounded by the mold surface of the mold material, fill the molding space with a thermosoftening resin material, and after curing the thermosoftening resin material, remove the female cylinder. The object of the present invention is to manufacture a lens barrel unit in which the female barrel is screwed together and molded with the male barrel by removing other mold members.

In the case of interchangeable lens barrels for single-lens reflex cameras, lenses for intermediate cameras equipped with lens shutters, video camera lenses, or lens barrels for electronic still cameras, an intermediate barrel is provided between the male and female barrels. When manufacturing a lens barrel in which a male cylinder and a female cylinder are configured to rotate relative to each other on the inside and outside of the intermediate cylinder, a plurality of molds must be prepared if the conventional molding technique described above is used. In other words, when considering the case of using the technique disclosed in Japanese Patent Publication No. 60-4768, the female cylinder is made in advance using the first molding mold, and the female cylinder made using the first molding mold is then transferred to the second molding mold. As a result, two molds, the first and second molds, are required to make the male cylinder and the female cylinder.

Furthermore, in the case of the prior art, three molds are required to make a lens barrel with a three-layer structure in which an intermediate barrel is provided between a male barrel and a female barrel.

(Object of the present invention) The present invention provides three
The purpose of the present invention is to obtain a method for manufacturing a lens barrel unit that can inexpensively obtain a lens barrel with a complicated structure through a short manufacturing process using a mold that requires fewer molds when obtaining a lens barrel with a layered structure. shall be.

(Description of Embodiment) An embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4. FIG. 1 shows an intermediate cylinder provided between a male cylinder and a female cylinder to be described later, and the intermediate cylinder 1 is provided with a circumferential groove 1a on its inner periphery. Holes 1b are provided at a plurality of locations on the end face for holding the intermediate cylinder 1 in a mold to be described later.

Figure 2 shows the cross-sectional structure of the mold, where 2 is the movable core, 4 is the fixed core, 6 is the middle piece fixed to the outside of the movable core 2, and 8 is fixed to the outside of the fixed side 23-4. The fixed side mold member 10 is the middle piece 6
The movable side mold member fixed to the outside of each is shown.

The intermediate cylinder 1 shown in FIG. 1 is held by inserting a holding pin 6a provided at one end of the intermediate piece 6 into a hole 16 of the intermediate cylinder 1.

As shown in FIG. 2, when the intermediate cylinder 1 is held by the holding pin 6a of the middle piece 6 and the movable mold member 10 is closed,
A molding cavity 12 is formed around the intermediate cylinder 1 on the inside and outside of the intermediate cylinder 1 by the cores 2 and 4 and the movable and fixed mold members 10 and 8.

In the above state, molten resin is injected into the molding cavity through the injection ports 8a, 8a, the cavity is filled with the resin, and the injection is stopped after the cavity is completely filled with the resin.

The mold is then cooled to cool the injected resin.

After the cooling, the movable mold member 10 is opened in the direction of arrow B from the position _A1 - _A2 in FIG. 2, and the molded body 12 filled in the gap is taken out from the mold. FIG. 3 shows a sectional view of the molded body 12 containing the intermediate cylinder 1 taken out from the mold. In the state shown in FIG. 3, the inner molded body A of the intermediate cylinder 1 and the outer molded body 12B are connected to each other at a connecting portion 12C and are integrally formed.

Next, the connecting portion 12C of the molded body 12 shown in FIG. 3 is removed by cutting, melting, or the like to separate the inner molded body 12A and the outer molded body 12B. (4th
(See figure) In this state, as shown in FIG.
The intermediate cylinder 1 and the outer molded body 12B can rotate relative to each other on their relative contact surfaces. 5 to 8 show examples in which the present invention is applied to a lens barrel. FIG. 5 shows an axial cross-sectional view of the lens barrel, and in the figure, 20 is a fixed barrel having a mount member 20A at one end for coupling with a camera (not shown).

Reference numeral 22 denotes a female helioid cylinder, and a circumferential protrusion 20B formed on the outer periphery of the inner periphery of the fixed cylinder 20 is provided.
It has a circumferential groove 22A that engages with the lens holding cylinder 24, a helioid portion 22B that threadably engages with the lens holding cylinder 24, and a threaded hole that threadably engages the distance operation ring 26.

28 is a scale ring fitted around the outer periphery of the fixed cylinder 20.

30 is an exterior ring fixed to the lens holding cylinder 24.

Reference numeral 32 denotes a linear guide cylinder fixed to the fixed cylinder 20, and a key protrusion 32A is provided from the inner diameter thereof, and the key 32A engages with the linear groove 24A of the lens holding cylinder 24. _L1〜
L ₆ is a focus lens held in the lens holding tube 24 . In the lens barrel configured as shown in FIG. 5, by rotating the operating ring 26 in a direction around the optical axis, the helioid tube 22 is rotated around the optical axis due to the relationship between the circumferential protrusion 20B and the circumferential groove 22A with the fixed tube 20. Accordingly, the lens holding cylinder 24 is moved straight in a direction parallel to the optical axis by the linear key and keyway, and focus adjustment is performed.

In the structure of the lens barrel shown in FIG. 5, an example in which the fixed barrel 20, scale ring 28, and helioid barrel 22 are manufactured according to the present invention shown in FIGS. 1 to 4 is shown in FIGS. 6 to 8. Shown. FIG. 6 shows a fixed tube 20 made in advance from a metal material or a resin material. 2
0C is a holding hole in the mold, 20d is a key cylinder 32
This is a screw hole for fixing with a screw.

A stepped portion 20C is provided on the outer periphery of the fixed cylinder 20 to fit and hold a scale ring 28, which will be described later.

FIG. 7 shows a sectional view of the mold with the fixed cylinder 20 held in the mold, and 34A, 34B are 23-, 3
Reference numeral 6 indicates a fixed mold member, and 38, 40, and 42 designate movable mold members. The inside and outside of the fixed cylinder 20 in the radial direction are 2
3-34B and the fixed side mold member 36, and in the thrust direction, the holding pin 42A extending from the movable side mold member 42 engages and holds the aforementioned hole 20C, thereby holding the fixed cylinder 20 in the mold. do. In the configuration of the mold shown in FIG.
6, 38, 40, 42 form gaps 44, 46. Gates 38a,
Molten resin material injected from an injection unit (not shown) is injected from 42a. A helioid portion 34B is formed on the outer periphery of the 23-34A. A resin is injected into the void, and after cooling, the molded body is taken out from the mold. As shown in FIG. 8, the molded body taken out from the mold has a molded part in the area of the void 44.
The helioid tube 22 shown in the figure becomes the molded part of the gap 46, which becomes the scale ring 28. As the cooling of the molded resin progresses, a gap is created between the fixed tube 20 and the helioid tube 22 due to cooling contraction of the helioid tube 22, and the rotation of the helioid tube 22 is maintained by this gap. Further, the scale ring 28 is contracted by cooling and is fixed to the stepped portion of the fixed cylinder 20 by contracting. It is fixed to form a fixed barrel of the lens barrel shown in FIG. The embodiments shown in FIGS. 9 to 12A and 12B show examples in which the fixed cylinder serving as the intermediate cylinder is divided into a plurality of bodies.

In the example of FIG. 5, the fixed cylinder 20 serves as an intermediate cylinder.
is shown as a single integral member, but in the case of long lenses such as long focal length lenses, the fixed tube will also be long, and if such a fixed tube is fixed to the mold as an integral member, the mold structure will also become large, which is inconvenient. It is. The example shown in FIG. 9 and subsequent figures shows a case where the fixed tube is divided into parts in view of the above-mentioned problem. The same reference numerals as in FIGS. 5 to 8 indicate the same members. 50 is the fixed cylinder 20 and screw 52
The figure shows an intermediate cylinder that is integrally connected with the cylinder, and has a circumferential projection 50A, a screw hole 50B, and a holding hole 50C on the inner periphery. (FIG. 10) FIG. 11 is a sectional view of the intermediate cylinder 50 held in the mold. FIG. 12A shows the molded product taken out from the mold, and FIG. 12B shows the molded product with a portion C connecting the scale ring and helioid tube removed.

A fixed cylinder is attached to the intermediate cylinder 50 of the unit formed as shown in FIG. Since it can be integrally formed as a cylinder, the number of molds used to obtain the three-layer lens barrel structure can be reduced compared to when conventional techniques are used.

Further, the engaging portions 1b, 12 between the intermediate cylinder 1 and the inner cylinder 12A
It is also possible for a to be a screw connection.

[Brief explanation of drawings]

1 to 4 show the first embodiment, and the fifth embodiment shows the first embodiment.
8 to 8 show the second embodiment, and FIGS. 9 to 12A and 12B show the third embodiment, respectively.
FIGS. 1, 6, and 10 are cross-sectional views of an intermediate barrel that is a lens barrel component and is made in advance and used as a mold member. FIG. 2, FIG. 7, and FIG. 11 are sectional views of the main parts of the mold. FIGS. 3, 8, and 12 A and B are cross-sectional views of the molded bodies molded inside and outside the intermediate cylinder, taken out from the mold. FIG. 4 is an explanatory diagram in which the connection between the inside and outside of the intermediate cylinder 1 is removed. FIGS. 5 and 9 are sectional views of main parts of the lens barrel. 1, 20, 50...Intermediate tube, 22...Menuhelioid tube, 24...Lens holding tube, 26...Operation ring.

Claims (1)

[Claims] 1. An intermediate cylindrical member made of a metal material or a resin material is held in a mold so that gaps for resin injection are provided inside and outside the intermediate member, and a resin is injected into the gaps. A method for manufacturing a lens barrel unit, characterized in that a molded body is produced by molding, and then taken out from the mold, and a part of the molded body is removed to separate the molded body inside and outside of the intermediate cylinder member. .