JPS61297112A - Manufacture of specular barrel for drawing-out of lens - Google Patents

Abstract

PURPOSE:To obtain accuracy of a specular barrel easily and to omit a process requiring manhour, by a method wherein a plurality of pieces of spheres is made to abut against a cylindrical surface of a forerunner of the specular barrel by a supporting member at predetermined positions and a resin layer is formed by casting and curing resin into a void between the forerunner of the specular barrel and the cylindrical surface. CONSTITUTION:A stationary cylinder 20 of a specular barrel for drawing-out of a lens is inserted into a main body 8 of a casting mold for positioning. The a positioning block 18 of a fixing pin is fitted to a predetermined position and steel balls 9-11 are inserted into the block 18 by fitting them to the tip of magnetized fixing pins 12-14. Then a holding plate 19 of the pin is fitted by inserting press springs 15-17. Hereupon, the steel balls 9-11 are positioned at positions of fitting in a multiple flighted thread groove of a rotating cylinder of a specular barrel for drawing-out of the lens. To fix the steel balls 9-11 on a cylindrical surface, epoxy series resin is cast through a resin casting port 25 and the stationary cylinder 20 is unloaded by removing a jig after completion of cure. Accuracy of the specular barrel is obtained easily by keeping the positioning block of the pin processed by improving accuracy of the same.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a lens barrel for extending a lens.

2. Description of the Related Art Traditionally, video cameras, still cameras, etc. have been equipped with a fixed barrel and a rotating barrel within the lens barrel, and the focusing lens is supported by the rotating barrel, and the focusing lens is rotated by rotating the rotating barrel. A lens extension mechanism that performs focusing is known.

An example of the structure of the above-mentioned conventional lens feeding mechanism and its manufacturing method will be described below with reference to the drawings.

FIG. 6 shows a lens extending mechanism of a conventional lens barrel. In Fig. 6, 1 is a fixed barrel, 2 is a rotating barrel that supports focusing lenses 3 to 5, 1a is a multi-threaded thread in the circumferential direction (male thread), and 2a is a multi-threaded thread in the circumferential direction ( 6 is a lens spacer, and 7 is a lens fixing ring.

In the lens barrel configured as described above, when focusing, the rotating barrel 2 is rotated manually or driven to rotate by a motor, and the rotating barrel 2 is reciprocated in the axial direction to achieve focusing. Let's do it.

Next, a first method of manufacturing a conventional lens barrel feeding mechanism will be described. Aluminum or wood 3,
.

Attach the fat cylindrical member to a lathe or helicoid lathe,
Multi-thread grooves are machined on both the rotating and fixed cylinders. After processing is completed, the rotating cylinder and fixed cylinder are combined and wrapped for final finishing.

The problem that the invention aims to solve However, in the above configuration, the rotating cylinder.

When machining multi-thread grooves on the fixed cylinder, accurate shape accuracy of both the concave and convex portions is required, so the machining is highly difficult. In addition, it is necessary to perform lapping processing by combining both the thread grooves after processing the thread grooves, which has the problem of requiring a lot of man-hours.

In view of the above-mentioned problems, the present invention provides a method for manufacturing a lens barrel for extending a lens, which is easy to manufacture, easy to achieve accuracy, and can reduce the number of man-hours.

Means for Solving the Problems In order to solve the above-mentioned problems, the method of manufacturing a lens barrel for feeding out a lens according to the present invention includes a mold member that forms a cylindrical surface and a mold member that fits into the mold member. A lens barrel precursor having a cylindrical surface spaced from the mold device at a distance smaller than the diameter of the sphere is placed in a mold device having a plurality of spherical support members provided in the circumferential direction and capable of advancing and retracting from the mold device. A plurality of spheres are supported coaxially with the cylindrical surface of the molding device, and a plurality of spheres are brought into contact with the cylindrical surface of the lens barrel precursor at predetermined positions by the support member, thereby forming a gap between the lens barrel precursor and the cylindrical surface of the molding device. Inject resin into.

It solidifies to form a resin layer.

action The effect of this technical means is as follows.

That is, by ensuring the precision of the sphere, the precision of the cylinder, and the precision of the mold member, it becomes possible to easily and accurately provide a spherical protrusion at a predetermined position on the cylinder. As a result, helicoid lathe processing, which was conventionally performed when manufacturing the lens feeding mechanism, was adopted.

It becomes possible to omit processes that require many man-hours, such as wrapping.

Examples Below, regarding the manufacturing method of the lens barrel of the present invention,
This will be explained with reference to the drawings.

FIG. 1 is a cross-sectional view of the main parts of a casting mold for manufacturing a fixed tube of a lens barrel according to an embodiment of the present invention, in which 8 is a casting mold body, 9 to 11 are steel balls, 12 to 14 are magnetized steel ball fixing pins, 15 to 17 are presser springs for fixing the steel balls, 18 is a positioning block for the steel ball fixing pins, 1
9 is inside the steel ball.

FIG. 2 is a perspective view of the casting mold, in which 22 to 24 are holes into which steel ball fixing bottles are inserted, 25 is a resin injection port, and 26 is a perspective view of the casting mold.
．． 27 is a block forming the resin injection port. FIG. 3 shows a fixed barrel of a lens barrel for extending a lens manufactured according to an embodiment of the present invention, and FIG. 4 shows a fixed barrel of a lens barrel for extending a lens produced according to an embodiment of the present invention. FIG. 1 is a sectional view of a main part of a lens extending mechanism using a lens barrel manufactured according to an embodiment of the present invention.

Next, a method of manufacturing the lens barrel for extending the lens will be explained.

First, go to the casting mold body 8 shown in Figs. 1 and 2.
/ Insert and position the fixed tube 2o of the lens barrel for extending the lens. Next, the fixing bottle positioning block 18 is attached to a predetermined position, and the steel balls 9 to 11 are attached to the magnetized fixing pin 12.
~14 and inserted into the positioning block 18. Then, the presser springs 16 to 17 are inserted, and the retaining plate 19 of the steel ball fixing pin is attached. Here steel ball 9-1
1 is positioned at a position where it fits into a multi-threaded thread groove on a rotating barrel of a lens barrel for extending the lens. In order to fix the steel balls 9 to 11 on the cylindrical surface, epoxy resin is poured through the resin injection port 25 and cured at room temperature or by heating. After hardening is completed, the steel ball fixing retaining plate 19. Presser springs 15-17. Remove the fixing pins 12 to 14, remove the fixing cylinder 2o from the casting mold body 8 while keeping the blocks 26 and 27 forming the resin injection port 26 and the fixing positioning block 18 in close contact with the resin, and finally Blocks 26 and 27 having resin injection ports are divided into two parts and removed from the fixed cylinder 2o, and the positioning block 18 is also removed from the fixed cylinder.

Fixing the lens barrel for extending the lens as described above 7.
-7 Once the cylinder is manufactured, the accuracy of the lens barrel can be easily obtained by processing the pin positioning block with high precision, and the manufacturing method is also easy, and the rotating cylinder has multiple female threads. A lens extension mechanism can be manufactured by combining it with a tube. Further, since the lapping process required when manufacturing the lens feeding mechanism is not necessary, the number of man-hours can be reduced.

In addition, in the description of the above embodiment, epoxy/based resin is used to fix the steel ball to the cylindrical surface, but it is also possible to use other thermosetting resin instead.

Furthermore, if a two-component type reactive liquid material (for example, a reactive nylon material) is used as the material for fixing the steel ball to the cylindrical surface, the following effects can be obtained.

(1) A lens feeding mechanism having good impact strength and heat resistance can be manufactured.

(2) Thermosetting materials require 20 minutes or more to complete solidification after injection, whereas two-component reactive injection molding nylon can be solidified in about 3 minutes.

(3) For thermosetting materials, the viscosity at the time of injection is 2000-5
000 centipoise, whereas two-component reactive injection molding nylon has a viscosity of 10 to 20 centipoise during injection.
Due to its low centipoise, it works well even when the cylindrical surface is wide or the gap for forming the resin layer is narrow.
injection.

It is possible to fill and solidify.

This two-component type reactive injection molding nylon contains ε-caprolactam and various polyols, or a copolymer of ε-caprolactam and polyol and ε-caprolactam.
High molecular weight nylon can be obtained in about 3 minutes by anionic polymerization at 0°C to 160'C, and the trade names of specific materials include UX-B and U manufactured by Ube Industries, Ltd.
X-cs etc. can be used.

Effects of the Invention As described above, the present invention provides support for a mold member that forms the surface of a cylindrical surface, and a plurality of spheres that fit into the mold member, are movable toward and away from the cylindrical surface, and are provided in the circumferential direction. A lens barrel precursor having a cylindrical surface spaced from the molding device at a distance smaller than the diameter of the sphere 91, -7 is coaxially supported with the cylindrical surface of the molding device in a molding device having a member. A plurality of spheres are brought into contact with the cylindrical surface of the steel ball at predetermined positions by the supporting member, and a resin is injected and solidified into the gap between the lens barrel precursor and the cylindrical surface of the molding device to form a resin layer. This method manufactures a lens barrel for fixed lens extension, and the following effects can be obtained.

(1) Since it is easy to ensure the accuracy of the position of the steel ball, the accuracy of the lens barrel can be easily obtained.

(2) The lens barrel can be manufactured easily.

(3) In combination with a rotary tube having multiple threads, a lens feeding mechanism can be easily obtained.

(4) Since finishing processing by lapping is not required, the number of man-hours can be reduced.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a main part of a casting mold for manufacturing a fixed barrel of a lens barrel for lens feeding in the first embodiment of the present invention, Fig. 2 is a perspective view of Fig. FIG. 4 is a perspective view of a fixed barrel manufactured according to an embodiment of the invention, FIG. 4 is a cross-sectional view of the main part of the lens barrel b10 page feed mechanism of the lens barrel in implementation ρ1 of the present invention, and FIG. FIG. 3 is a sectional view of a main part of a lens feeding mechanism. 2...Rotating barrel of lens barrel, 3-5...
Lens, 8...Casting mold body, 9-11...
... Steel ball, 12-14 ... Steel ball fixing pin, 1
6 to 17...presser foot, 2o...fixing cylinder, 21...casting resin layer. Name of agent: Patent attorney Toshio Nakao and 1 other person
~14-11 Steel ball U foot pin tS~/7---Press bar winter Fig. 2 Fig. 4 3rd rlA Fig. Suisha

Claims (1)

[Claims] fitting into a mold member forming a cylindrical surface and the mold member;
a lens barrel precursor having a cylindrical surface spaced from the mold device at a distance smaller than the diameter of the sphere; a plurality of spheres are brought into contact with the cylindrical surface of the lens barrel precursor at predetermined positions by the support member, and the lens barrel precursor and the mold device are A method of manufacturing a lens barrel for extending a lens, which involves injecting resin into the gap between the cylinder surface and solidifying it to form a resin layer.