JPS63154336A - Multilayer structure resin molded form - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a multilayer resin molded product that is formed as a lens barrel in an optical device, a video device, for example, a photographing device, or a lens barrel in an office machine. In particular, it relates to molded products such as lens barrel parts that enable electrical continuity.

[Background of the invention]

To explain the following using a camera lens barrel as an example, conventionally, this type of plastic molded lens barrel product was only molded entirely from the same material, and multiple different materials were not laminated in a sandwich-like manner. Not yet. For example, PC-G
(Glass fiber polycarbonate), the entire body was molded with this PC-G-fl. In addition, when the part requires electrical conductivity, the entire part is molded from a single material such as PC-G material, which is a combination of PC-G and carbon.

A more specific explanation will be given with reference to FIG. 5, which shows the lens barrel structure of these cameras.

As shown in Figure 5, focusing lens upper 1 + variable magnification lens L2
．． In a configuration including a correction lens L3 and an imaging lens L4, a focusing lens LJlf is held in a focusing lens holder 1, and this focusing lens holder 1 is connected to a lens fixed lens barrel 2 by a helicoid coupling, and the focusing lens holder 1 By rotating the focusing lens L1, the focusing lens L1 is extended in the optical axis direction.

Further, the variable power lens L2 and the correction lens L3 are held by a lens holder 3 and a lens holder 4, respectively, and these lens holders 3. The lens holder 4 is guided by a guide bar 5 and the like using a well-known three-bar system so that it can move in the optical axis direction. The amount of movement of the variable magnification lens L and the correction lens L3 in the optical axis direction is determined by a cam lift 6a provided on a cam ring 6 rotatably held in the fixed lens barrel 2;
8b. The cam ring 6 is the lens fixed barrel 2
It is adapted to rotate in response to the rotational movement of a zoom operation ring 7 fitted on the outer periphery of the zoom ring 7. Moreover, the imaging lens L4 is
It is held in a rear fixed barrel 14 by an imaging lens holder 13 via an aperture 12 and fixed with screws 15 .

The cam ring 6 is held between a front mask plate 8 and a rear mask plate 9 that hold three guide bars 5 inside the lens fixed barrel 2.

In the above configuration, for example, the fixed lens barrel 2
Since this is a basic component of the lens barrel, it must have sufficient mechanical strength, and in order to guarantee the fitting diameter or overall length under temperature conditions, it must be made at a temperature close to that of metal. It is necessary to use materials with a coefficient of expansion. On the other hand, in cases where an electrical shielding effect is required as a u1wfJ member, a carbon-containing polycarbonate material mixed with carbon fiber is used, and the whole is molded as a molded product of a plastic material having electrically conductive properties. There is a need.

In this way, in order to mold a molded product from a single material while satisfying the required properties as a structural member or as a functional member such as conductivity,
For example, it is necessary to use a material made of polycarbonate mixed with glass fiber or carbon material.

However, when such a material containing glass fiber or carbon material is used, other problems may arise depending on the use of the molded product. For example, a focusing lens holder 1 that is connected to a lens fixed lens barrel 2 with a helicoid screw.
If glass fibers are protruding from the surface of the lens fixed barrel 2, sliding may occur at the threaded joint with the cam ring 6, the radial fitting portion with the zoom operation ring 7, etc. This may cause problems such as scratches during movement, or in severe cases, play in the fitting portion.

Therefore, there is a method to overcome some of the functionality required of such molded products, such as electrical conductivity, good surface smoothness, and low friction by forming the molded product as a layered structure of different materials. For example, it has been proposed in Japanese Patent Publication No. 50-2864. This is a method generally referred to as a sandwich molding method, and specifically, a resin molded article having a multilayer structure is formed in the following manner.

First, a polycarbonate resin material that will form the surface of the lens barrel is injected into the cavity of the mold, and then an electrically conductive material such as carbon (and glass fiber if necessary) is mixed in to form the core. By injecting resin material,
The surface layer (hereinafter referred to as skin layer) is a smooth resin layer,
A molded product is formed by using an electrically conductive (or even higher strength) resin layer as a core (hereinafter referred to as a core layer).

At Jinkoro, if we examine in more detail the uses and modes of use of multilayer resin molded products molded in this way, we find that, for example, it is possible to impart conductivity to the molded product for purposes such as electromagnetic shielding. Needless to say, in the case of a molded product, it is necessary to ensure not only the conductivity of the molded product itself but also the electrical continuity between the molded product and other members.

If it is possible to obtain a molded product that does not require special processing steps to ensure electrical continuity with other members, the effect in actual use will be extremely large.

(Objective of the Invention) The present invention has been made from this point of view, and its purpose is to form a layered structure of a conductive core layer and an insulating skin layer covering the surface thereof using a sandwich molding method. In a resin molded product configured to have a resin molded product, electrical continuity between the core layer of the molded product and other members can be automatically obtained in conjunction with other operations. The purpose of the present invention is to provide a multilayer structure resin molded product.

[Summary of the invention]

The multilayer structure resin molded product of the present invention, which was made for this purpose, is characterized by:
A prepared hole for screwing is formed to have a layered structure including a core layer made of a conductive material and a skin layer made of an insulating material covering the surface of the core layer, and has an inner surface covered with the skin layer by the molding. The inner diameter of the core layer covered with the skin layer in the pilot hole for screwing is the outer diameter of the thread of the screw member screwed into the pilot hole. It is located in a place where the diameter is smaller than the dimensions.

The core layer in the molded article has electrical conductivity, and
Of course, in addition to this, for example, glass fiber or the like may be blended to impart high strength properties.

As for the resin material constituting the molded article as described above, examples of the material for the core layer include glass fiber-filled polycarbonate, and examples of the material for the skin layer include natural polycarbonate.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 shows the lens barrel structure of a camera constructed using a lens fixed lens barrel 2, etc. as a molded product of the present invention, and the parts are substantially the same as those of the conventional example shown in FIG. are shown with the same reference numerals.

A focusing lens holder 1 holds a focusing optical system L1, and is connected to a helicoid portion of a fixed lens barrel 2 with a helicoid screw. 6 is a zoom cam ring, which is held in the inner diameter part.
The VfJ ring and C moving ring shown by 3 and 4 are used to change the direction of the optical axis according to the zoom cam lift, and the diameter fitting portions shown by 6d and 6e connect the lens fixed lens barrel 2. It is diametrically fitted to the inner diameter part and is rotatable and slidable. Reference numeral 7 denotes a zoom operation ring, which is rotatably fitted into the fixed lens barrel 2, and the zoom operation is performed by linking the inner protrusion 7a and the notch 6C of the cam ring 6. The rotational movement of the ring 7 is transmitted to the cam ring 6.

18 is a relay tube, and an afocal lens L5 is attached to the inner diameter part.
is held and screwed to the lens fixed lens barrel 2 with screws 17. Reference numeral 14 denotes a rear fixed barrel, which internally supports a lens holder 13 holding an imaging optical system L4 in its inner diameter part;
The relay tube 18 is tightened with a mounting screw 19.

Reference numeral 16 denotes a mount holder, to which an image pickup element unit 21 can be attached to the rear end surface 16b, and is coupled to the rear lens barrel with attachment screws 20.

In the above configuration, the lens barrel 2 of this example has a core layer 2
As a multilayer resin molded product having a skin layer 2b and a skin layer 2b,
Furthermore, the material of the core layer 2a contains 20% carbon fiber.
, a polycarbonate blended with 10% glass fiber is used, and the material of the skin layer 2b is a descending carbonate blended with no above blended material.

Also, the screw 17 of this lens fixed barrel 2 allows the middle 1! As shown in an enlarged view in FIG. 2, the screw fixing portion connected to the tray 18 has a self-tapping effect when the screw is screwed in to ensure electrical continuity between the screw 17 and the core layer 2a. It has the characteristics of

That is, at appropriate locations on the rear end surface portion 2C of the lens fixed lens barrel 2, pilot holes 2d for screws for connection with the relay tube 18 are formed in advance during sandwich molding.On the other hand, the relay tube 18 is also Similar to the fixed lens barrel 12, it is formed using a sandwich molding method to have a structure including a core layer 18a made of a polycarbonate material mixed with carbon and glass fibers, and a skin layer 18b made of a natural polycarbonate material. A plurality of blank holes 18c for the screws 17 are formed in advance. Middle@i#i1B
In the blank hole 18C, the core layer 18a is exposed on the surface during sandwich molding or by processing after the molding, so that electrical continuity with the screw 17 can be obtained when the screw 17 is fitted. Set it in The shape of the screw and the area around the pilot hole 2d is such that t<h, where t is the thickness of the skin layer on the inner surface of the pilot hole, and h is the thread height of the self-tapping screw 17, and the core of the pilot hole 2d is By making the inner diameter of the layer smaller than the thread system d of the screw 17, by screwing the screw 17 into the prepared hole 2d of the lens fixing barrel 2, the thread 17a of the screw 17 can be inserted into the skin layer 2b.
break and wedge into the core layer 2a of the lens fixed barrel 2,
Electrical continuity with the layer 2a can be ensured.

FIG. 2(b) shows a state in which the fixed lens barrel 2 and the relay barrel 18 are connected with the screw 17, and the core layer 2a of the lens fixed lens barrel 2 and the screw 17 are electrically connected via the screw thread 17a. The state in which the screw 17 and the core layer 18a of the relay tube 18 are electrically connected is shown.

Furthermore, in the same manner as the coupling structure between the lens fixed lens barrel 2 and the relay barrel 18 as described above, the relay barrel 18 and the rear part 1ti14 are connected to each other.
A coupling structure is provided in which electrical continuity is ensured through the screws 19 between the two.

FIGS. 3(a) and 3(b) show other structural examples of the prepared hole portion for screwing the molded product according to the present invention.

In this example, the shape of the pilot hole 50d for the screw of the sandwich molded product is changed to 50a, 50a,
This is an example in which a projecting portion such as 50b is provided. This allows the skin layer material 50b to escape more when the core layer material 50a is injected, so that the screw pilot hole S
This makes it possible to further reduce the thickness t of the skin layer around the od. In addition, in Fig. 3(b), screw 5
1, the skin layer around the screw pilot hole is torn by the screw thread 51a, and the screw 51 and the core material 50a are electrically connected to each other by biting into the core layer 50a. FIG. 2B is a diagram illustrating a state substantially similar to that in FIG. 2(b).

Next, an example of manufacturing a multilayer resin molded product having a pilot hole for screwing as described above will be described.

In the molding apparatus shown in FIG. 4, 30.31 is a fixed plate, and the fixed plate 30.31 is connected to the first injection cylinder 32A for injecting the skin layer resin material and the second injection cylinder 328 for injecting the core layer resin material. It has sprues 30a and 30b for connection. 34 is a runner plate having a runner 34a, and 36 and 38 are molds provided with molding gaps.

The gate 34b for injecting the molten resin from the runner plate 34 into the molding gap is the lens fixed lens barrel 2 of the molded product shown in FIG.
A disk gate is provided at the center of the distal end surface 2e of the disk.

The operation of the molding device begins with injecting a predetermined amount of skin material from the first injection cylinder 32A into the gap through the sprue, runner, and gate. Polycarbonate resin or the like is used as the skin material. After injecting a predetermined amount of the skin material, the core material is injected from the second injection cylinder through the gate. By injecting the core material, the skin material previously injected into the void is pressed against the peripheral wall of the void by the core material, resulting in a molded product having a skin layer on the surface and a core layer in the core.

In particular, in the fixed lens barrel of this example, as shown in FIG. ,
Compared to the entire skin layer of the fixed lens barrel 2, the wall thickness is t.
It becomes thin like this. Therefore, since the skin layer of the pilot hole 2d of the lens fixed lens barrel 2 of this example is thin, the skin layer is easily broken by the self-tapping action of the screw, ensuring electrical continuity between the screw 17 and the core layer 2a. The effect is that it is easy to do.

〔Effect of the invention〕

As described above, the resin molded product of the present invention is made by sandwich molding, for example, a lens fixed lens barrel, which is a component of a camera lens barrel, into a laminated structure of a skin layer and an electrically conductive core layer. In some cases, the pilot hole for a self-tapping screw for attaching another component has a structure that automatically establishes electrical continuity between the screw and the core layer when the screw is screwed in. As a product, it has the effect of having good assembly properties.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a diagram showing an outline of the configuration of a lens barrel of a camera incorporating a molded product according to the present invention, and Fig. 2 (a),
FIG. 3(b) is a diagram for explaining a state when a screw member is screwed into a pilot hole portion for screwing the molded product according to the present invention, and FIG. 3(a). (b) is a diagram for explaining the state when a screw member is screwed into the pilot hole for screwing of another example of the molded product of the present invention, and FIG. FIG. 5 is a diagram showing an example of a molding apparatus used for manufacturing the lens barrel, and FIG. 1... Focusing lens holder 2... Lens fixed lens barrel 2a... Core layer 2b... Skin layer 2C
... Rear end surface part 2d ... Pilot hole for screwing 2e ... Tip 2f ... Skin layer 2g
... Bottom flame peripheral part 3.4 ... Lens holder 5 ... Guide bar 6 ...
・Cam ring 1ia, [ib...cam lift 6
d, 6e...Diameter fitting part 7...Zoom operation ring 7
a... Inner protrusion 8... Front mask plate 9.
... Rear mask plate 12 ... Diaphragm 13 ... Lens holder 14 ... Rear fixed tube 15 ... Screw
16... Mount holder 17... Screw
17a... Thread 18... Relay tube 18a.
...Core layer 18b...Skin layer 18c...1
9... Screw 20... Screw 21... Imaging element unit 30.31... Fixing plate 30a, 30b... Sprue 32A... First injection cylinder 32B... Second injection cylinder 34. ...Runner plate 34a...Runner 34b...Gate 36.
38...Mold 50...Molded product 50a...Core layer material 50b...Skin layer material 50d...Prepared hole for screw 51...Screw 51a...Thread thread Φ ^ Fig. 2 Figure 4

Claims (1)

[Claims] A screw that is formed by a sandwich molding method to have a layered structure including a core layer made of a conductive material and a skin layer made of an insulating material covering the surface of the core layer, and has an inner surface covered by the skin layer by the molding. The resin molded product is formed to have a pilot hole for screwing, and the inner diameter of the core layer covered with the skin layer in the pilot hole for screwing is the same as that of the screw member screwed into the pilot hole. A multilayer resin molded product characterized by having a diameter smaller than the outer diameter of the thread.