JP2025085661A - Optical equipment and manufacturing method of optical equipment - Google Patents

Abstract

To provide a lens barrel part that is formed of carbon fiber reinforced resin, is excellent in strength including impact resistance performance, is reduced in size or weight and thickness, and has high-quality appearance.SOLUTION: Carbon fiber braid layers 3 and 5 assembled in a cylindrical shape and endlessly in a circumferential direction of the cylindrical shape, and a one-directional prepreg sheet layer 4 formed of carbon fiber oriented in one direction, are solidified and coupled to each other with thermoplastic resin to form a cylindrical body 1. The braid layer 3 and 5 are braided in an endless cylindrical shape on a mandrel in a circumferential direction of the mandrel, with the one-directional prepreg sheet layer 4 located therebetween.SELECTED DRAWING: Figure 1

Description

The present invention relates to a lens barrel part made of carbon fiber reinforced resin, an optical device, and a manufacturing method for the lens barrel part.

Conventionally, interchangeable camera lenses, such as telephoto lenses with focal lengths exceeding 300 mm, have been large and can weigh on the order of several kilograms. Even for optical devices with such a focal length range, there is a demand for products that are lightweight and strong, from the standpoint of ease of portability and improved operability when taking pictures.

Conventionally, the lens barrels of these types of large optical devices have been made of aluminum alloys or magnesium alloys because of their impact resistance. Furthermore, the hoods attached to these lenses have also been made of aluminum alloys because of their impact resistance. However, even though this type of metal material is a light metal, there are limitations to how light it can be made.

In recent years, therefore, it has been considered to manufacture lens barrels and hoods using carbon fiber reinforced resin (CFRP), which is carbon fiber impregnated with a thermosetting resin such as epoxy. When manufacturing lens barrel parts using carbon fiber reinforced resin (CFRP), for example, the shape is formed using a manufacturing method called the sheet winding method (SW method), in which a unidirectional prepreg sheet, in which carbon fibers are aligned in one direction, is wound around a cylindrical mold called a mandrel. The carbon fibers are then impregnated with a thermosetting resin such as epoxy and hardened in an autoclave or the like.

However, depending on the direction in which the carbon fibers are aligned and the combination of layers, there are cases where the resulting strength differs and the desired impact resistance cannot be achieved. To solve this problem, one should first laminate or stack unidirectional prepreg sheets in both the axial and circumferential directions of the lens barrel, integrating them into a single layer or multiple layers. A configuration has been proposed in which the final unidirectional prepreg sheet in the circumferential direction is then wrapped around the outside of the unidirectional prepreg sheet in the axial direction to obtain impact resistance (Patent Document 1 below).

Patent No. 4813619

As described above, in the SW method in which a unidirectional prepreg sheet is wrapped around a mandrel, a seam is inevitably generated in the manufacturing process, and there is a possibility that the strength varies at the seam, for example, that the impact resistance performance may decrease. Therefore, a countermeasure can be considered in which the unidirectional prepreg sheet is wrapped around the mandrel in multiple layers, and the position of the seam is shifted at that time. However, it becomes necessary to compensate for the deterioration of strength due to the seam by increasing the number of layers, and there is a concern that the effect of weight reduction will be reduced. In addition, the presence of the seam may cause a difference in cure shrinkage between the seam and other parts during the sintering process in which the impregnated resin is hardened and the shape is formed, and as a result, the roundness of the telescope barrel may not be obtained. In addition, if the impregnated resin is a thermosetting resin such as epoxy that has a long hardening time, there is a concern that productivity will decrease.

The objective of the present invention is to provide a lens barrel component that is made of carbon fiber reinforced resin, has excellent strength including impact resistance, is small or thin and lightweight, and has a high-quality appearance.

A first aspect of the present invention is an optical device configured to be detachable from an imaging device, the optical device comprising: a cylindrical body including a first carbon fiber layer which is a cylindrically braided layer, and a cylindrical second carbon fiber layer located on the outer circumferential side of the cylindrical body with respect to the first carbon fiber layer, the first carbon fiber layer and the second carbon fiber layer being bonded together by a thermoplastic resin which is an integrated combination of a first thermoplastic resin impregnated in the first carbon fiber layer and a second thermoplastic resin impregnated in the second carbon fiber layer; and an optical element, wherein the first carbon fiber layer is arranged so that the carbon fibers of the first carbon fiber layer are braided in a twill weave pattern inclined with respect to the axial direction of the cylindrical body and are endless in the circumferential direction of the cylindrical body, and the second carbon fiber layer is a sheet-shaped carbon fiber layer.
A second aspect of the present invention is an optical device configured to be detachable from an imaging device, the optical device comprising: a cylindrical body including a first carbon fiber layer which is a cylindrically braided layer, and a cylindrical second carbon fiber layer located on the inner circumferential side of the cylindrical body with respect to the first carbon fiber layer, the first carbon fiber layer and the second carbon fiber layer being bonded together by a thermoplastic resin which is an integrated combination of a first thermoplastic resin impregnated in the first carbon fiber layer and a second thermoplastic resin impregnated in the second carbon fiber layer; and an optical element, wherein the first carbon fiber layer is provided so that the carbon fibers of the first carbon fiber layer are braided in a twill weave pattern inclined with respect to the axial direction of the cylindrical body and are endless in the circumferential direction of the cylindrical body, and the second carbon fiber layer is a sheet-like carbon fiber layer.
A third aspect of the present invention is a method for manufacturing a cylindrical body, comprising the steps of: crossing and braiding a plurality of carbon fibers on a mandrel into a cylindrical shape to form a first carbon fiber layer impregnated with a first thermoplastic resin; forming a second carbon fiber layer on the mandrel impregnated with a second thermoplastic resin; and bonding the first carbon fiber layer and the second carbon fiber layer with the thermoplastic resin by heat treating them, wherein the bonding step is performed under pressure using an outer mold; in the step of forming the first carbon fiber layer, the first carbon fiber layer is provided such that the carbon fibers of the first carbon fiber layer are braided in a twill weave pattern inclined with respect to the axial direction of the cylindrical body and are endless in the circumferential direction of the cylindrical body; and in the step of forming the second carbon fiber layer, the second carbon fiber layer is a sheet-like carbon fiber layer.

The above configuration makes it possible to provide a lens barrel component that is made of carbon fiber reinforced resin, has excellent strength including impact resistance, is small or thin and lightweight, and has a high-quality appearance.

1A and 1B show the structure of a cylindrical body according to an embodiment of the present invention, in which FIG. 1A is a plan view of the cylindrical body, and FIG. FIG. 1 is a perspective view showing a braiding device according to an embodiment of the present invention. 1A and 1B show the structure of a cylindrical body according to an embodiment of the present invention, in which FIG. 1A is a plan view of the cylindrical body, and FIG. 4A and 4B show different structures of a cylindrical body according to an embodiment of the present invention, where FIG. 4A is a plan view of the cylindrical body, FIG. 4B is a cross-sectional view of the cylindrical body, and FIG. 4C is a cross-sectional view showing an enlarged portion of the cylindrical body. 1A and 1B show yet another different structure of the cylindrical body according to an embodiment of the present invention, where (a) is a plan view of the cylindrical body, (b) is a cross-sectional view of the cylindrical body, and (c) is a cross-sectional view showing an enlarged portion of the cylindrical body. 5A to 5D are explanatory diagrams showing how insert molding is performed on a cylindrical body according to an embodiment of the present invention. 1A and 1B show yet another different structure of the cylindrical body according to an embodiment of the present invention, where (a) is a plan view of the cylindrical body, (b) is a cross-sectional view of the cylindrical body, and (c) is a cross-sectional view showing an enlarged portion of the cylindrical body. 5A to 5D are explanatory diagrams showing how insert molding is performed on a cylindrical body according to an embodiment of the present invention. 1A and 1B show an experimental form according to an embodiment of the present invention, in which (a) is a plan view of a sample, (b) is a cross-sectional view of a joint, and (c) is an enlarged cross-sectional view of a part of the joint.

Below, a description will be given of an embodiment of the present invention with reference to the attached drawings. Note that the configuration shown below is merely an example, and those skilled in the art can appropriately change the detailed configuration, for example, without departing from the spirit of the present invention. Also, the numerical values used in this embodiment are for reference only and do not limit the present invention.

<Embodiment 1>
1(a) and (b) show a cylindrical continuous carbon fiber reinforced resin molded body (cylindrical body) constituting a lens barrel part in this embodiment in a plan view and a cross-sectional view. The cylindrical body 1 in FIG. 1(a) and (b) is a cylindrical body forming a lens barrel part in an optical device such as an interchangeable lens of a camera, for example, a lens hood, a focus ring, a body part of a lens barrel, etc., and is configured as a cylindrical continuous carbon fiber reinforced resin molded body. Here, the lens hood is a light-shielding part that blocks unnecessary light other than the shooting light from entering the shooting optical system, and is configured to be detachable from the tip of an optical device (imaging device) such as a camera. In addition, the lens barrel parts such as the outer tube, inner tube, and focus ring of the lens barrel can be considered as lens barrel parts that constitute the body part of the lens barrel that holds or adjusts optical elements such as lenses and mirrors.

The cylindrical body 1 in FIG. 1 is a fiber layer (sometimes called the first fiber layer) consisting of the carbon fiber braid layers 3 and 5 solidified with resin. For example, the resin for solidification is preliminarily contained in the fiber layer in the form of impregnation or coating. In other words, an intermediate body 2 is prepared in which a plurality of continuous carbon fibers are preliminarily impregnated with the resin for solidification in the form of impregnation or coating. The intermediate bodies 2 are crossed and assembled into a cylindrical shape to form fiber layers (first fiber layers) such as the braid layer 3 and the braid layer 5. At this time, it is preferable that the plurality of intermediate bodies 2 are assembled at an angle to the axial direction of the cylindrical body. In addition, a second fiber layer (one-directional prepreg sheet layer) may be formed together with the fiber layer (first fiber layer). In other words, the first fiber layer and the second fiber layer may be solidified with resin to form the cylindrical body 1. In that case, for example, it is preferable that the resin for solidification is preliminarily contained in the one-directional prepreg sheet layer 4 as the second fiber layer in the form of impregnation or coating.

In the cylindrical body 1 in Figures 1(a) and (b), a unidirectional prepreg sheet layer 4 (second fiber layer) is positioned between braided layers 3 and 5 (first fiber layers) each braided from a carbon fiber intermediate body 2. In this case, for example, the braided layer 5 (first fiber layer) is first braided (knitted) on a mandrel (Figure 2) using a braiding device, and then the outer braided layer 3 (first fiber layer) is braided using the braiding device with the unidirectional prepreg sheet layer 4 (second fiber layer) positioned therebetween.

The carbon fiber braided layers 3, 5 (first fiber layer) are braided, for example, into a cylindrical body that is endless in the circumferential direction from an intermediate body 2 made of thread-like or tape-like carbon fiber by a braiding device (Figure 2). In this case, the intermediate body 2 that constitutes the braided layers 3, 5 (first fiber layer) is braided in a direction inclined to the axial direction of the cylindrical body. In this embodiment, at least one layer of this carbon fiber braided layer may be braided. For example, the inner braided layer 5 may be omitted, and the outer braided layer 3 may be braided with the unidirectional prepreg sheet layer 4 (second fiber layer) sandwiched on the mandrel.

As shown in FIG. 1(b), to position a unidirectional prepreg sheet layer 4 (second fiber layer) between carbon fiber braided layers 3 and 5 (first fiber layer), for example, first braid a small amount of the end of the outer peripheral braided layer 3 on top of the inner peripheral braided layer 5. Then, insert the tip of the carbon fiber material of the unidirectional prepreg sheet layer 4 there. Also, if possible, a method may be used in which the required length of the outer peripheral braided layer 3 is braided on top of the inner peripheral braided layer 5, and then the carbon fiber material of the unidirectional prepreg sheet layer 4 is inserted from one end between the carbon fiber braided layers 3 and 5 (first fiber layer).

As described above, in this embodiment, when the cylindrical body 1 constituting the lens barrel part is manufactured from carbon fiber reinforced resin, the layer structure includes at least one layer of a braided layer (first fiber layer: 5, 3) of carbon fibers braided to form an endless form in the circumferential direction. That is, the braided layer (first fiber layer: 5, 3) of this embodiment is endless in the circumferential direction, and there is no seam of the carbon fiber layer that necessarily occurs in a structure in which only a one-directional prepreg sheet is wound around a mandrel as in a conventional structure. Therefore, there is no strength deterioration due to the seam of the carbon fiber sheet as in the conventional structure, and it is possible to construct a lens barrel part with excellent strength such as rigidity and impact resistance. In addition, since the braided layer (first fiber layer: 5, 3) can be braided in an endless form in the circumferential direction, there is no unevenness in the peripheral structure of the cylindrical body 1 due to the seam. For example, in the case of a cylindrical lens barrel part, a lens barrel part with excellent roundness can be obtained.

In this embodiment, when the cylindrical body 1 constituting the lens barrel part is manufactured from carbon fiber reinforced resin, at least one layer of braided carbon fiber layer (first fiber layer) that is braided to form an endless form in the circumferential direction may be used. For example, in the example of Fig. 1 (a) and (b), the unidirectional prepreg sheet layer 4 is disposed between the braided layers 3 and 5, but the unidirectional prepreg sheet layer 4 may be omitted and the cylindrical body 1 may be constructed with two braided layers 3 and 5. The braided layer 5 on the inner circumference side in Fig. 1 (a) and (b) may be changed to a unidirectional prepreg layer. Also, the unidirectional prepreg sheet layer 4 may be changed to a braided layer, in which case the cylindrical body 1 is formed by three braided layers. Also, one or several braided layers may be braided on the outer circumference of the braided layer 3.

The carbon fiber used as the material for the unidirectional prepreg sheet layer 4 is a filament-shaped carbon fiber bundle or, for example, a rectangular carbon fiber sheet, which contains carbon fibers oriented in one direction, for example, along the axial or circumferential direction of the cylindrical body 1. Carbon fibers oriented in the axial direction of the cylindrical body 1 are preferably easier to handle during manufacturing, and may provide good strength to lens barrel components used in a nearly horizontal position. The unidirectional prepreg sheet layer 4 may also be constructed by arranging several carbon fiber tapes separated into several pieces along the axial direction of the cylindrical body 1 along multiple axes. In this case, it is preferable that there are no gaps between the arranged tapes, but gaps are acceptable.

As described above, in this embodiment, in the cylindrical body 1 constituting the lens barrel component, in addition to the carbon fiber braided layers 3 and 5, a unidirectional prepreg sheet layer 4 containing fibers oriented in the axial direction of the cylindrical shape is arranged. This makes it possible to ensure strength and rigidity in the longitudinal direction, for example, in a long focal length, long (large), and heavy imaging optical system.

To solidify the cylindrical body 1 into the finished shape of the lens barrel part, after the braiding process is completed, the mandrel or the layered structure of the cylindrical body 1 is reattached to another mold that corresponds to the finished shape, and then the resin is impregnated and solidified. To solidify the resin, for example, heating with a heater or pressurizing with an autoclave is used. When sintering the resin for solidification, the shape can be regulated by applying pressure from the outside of the mandrel with another mold, if necessary.

For the resin impregnation and solidification, for example, a carbon fiber material that is pre-impregnated with a resin for solidification is used for the thread- or tape-shaped intermediate body 2 of the braided cord layers 3 and 5, or the unidirectional prepreg sheet layer 4. Alternatively, carbon fiber material that is not prepregged with resin may be used for these layers, and the resin for impregnation and solidification may be applied later by coating or spraying.

After solidification, the molten and solidified resin is distributed between the carbon fiber braid layers 3, 5 (first fiber layer) and the unidirectional prepreg sheet layer 4 (second fiber layer), bonding these layers together.

The solidification resin can be, for example, a thermoplastic resin such as polycarbonate, which is previously impregnated into the continuous carbon fibers of the braided layers 3 and 5 (first fiber layer) and the unidirectional prepreg sheet layer 4 (second fiber layer). Note that a thermoplastic resin is not necessarily a required material for the solidification resin, and those skilled in the art may change the solidification resin to a thermosetting resin or photocurable resin, etc., as necessary.

For example, in the case of the unidirectional prepreg sheet layer 4 (second fiber layer), the resin-impregnated carbon fiber material can be produced by processing a continuous carbon fiber sheet material having unidirectional orientation with a thermoplastic resin film using a heated roll or the like to integrate the material, thereby obtaining a prepreg sheet. The prepreg sheet can also be cut into threads or tapes to produce the intermediate body 2 for the braided layers 3 and 5 (first fiber layer). For example, the resin-impregnated carbon fiber material of the intermediate body 2 for the braided layers 3 and 5 (first fiber layer) can be a mixed fiber yarn made by mixing continuous carbon fiber and thermoplastic resin yarn. The continuous carbon fiber can also be impregnated by electrostatically attaching thermoplastic resin powder to it.

It is not easy to impregnate the intermediate body 2 with thermoplastic resin so that no small voids remain inside, and it is necessary to give flexibility to the intermediate body 2 when forming the braided layers 3 and 5, so the degree of impregnation of the thermoplastic resin into the continuous carbon fibers is preferably in a semi-impregnated state. A preferred semi-impregnated state is one in which the VF (fiber volume fraction) value set for the intermediate body 2 is 100% theoretically void-free, and the density of the resin is, for example, about 40% to 70% of the impregnated state.

In addition, in the thermoplastic resin impregnation process, a sizing agent may be used to increase the affinity between the carbon fiber and the thermoplastic resin. For example, by attaching an epoxy emulsion-based sizing agent to the carbon fiber, the interfacial adhesion between the carbon fiber and the thermoplastic resin can be increased. In this case, it is also desirable that the carbon fiber bundles are opened to obtain good resin impregnation.

The cylindrical body 1 shown in Figures 1(a) and (b) may be considered to have, for example, a cylindrical shape with a circular cross section, but the cylindrical shape is arbitrary. Any shape can be adopted, such as a cone shape, a cone shape in which the inclination angle of the cone shape changes in the axial direction, a horn shape, or a constricted shape. Furthermore, the shape of the cylindrical body 1 is not limited to a cone shape, but may also have a pyramid shape, etc. Furthermore, in a cone shape or constricted shape in which the inclination angle changes in the axial direction, an R shape can be given to the point where the inclination angle changes.

In this embodiment, the thermoplastic resin with which the carbon fibers are pre-impregnated is polycarbonate. The impact resistance of polycarbonate itself improves the toughness of the cylindrical body 1, and a high-strength lens barrel component can be obtained. In applications such as this embodiment, the viscosity average molecular weight of polycarbonate as the thermoplastic resin for solidification is preferably in the range of approximately 18,000 to 25,000. If the viscosity average molecular weight of polycarbonate is 18,000 or less, the toughness decreases, and if it is 25,000 or more, the melt viscosity tends to be high, and there is a possibility that the impregnation ability during the solidification (sintering) process may decrease.

Figure 2 shows the structure of a braiding device 6 that can be used in the braiding process of the carbon fiber braid layers 3 and 5 in Figure 1. In Figure 2, the braiding device 6 has an annular frame 7 with a through hole 9. The mandrel 8 is inserted near the axis of the through hole 9 of the annular frame 7 and positioned by a means not shown. The annular frame 7 has carriers 10 and 11 wound with braided threads 12 and 13 that constitute the intermediate body 2 of the braided layers 3 and 5. The carriers 10 and 11 are driven by a driving means not shown to move around the annular frame 7 in opposite directions while moving on an eight-shaped track 14 formed around the pipe body 15. As a result, the braided layers 3 or 5 of the cylindrical body 1 in Figure 1 are braided from the braided threads 12 and 13 by, for example, a braiding method. In Figure 2, 16 is a simplified illustration of a cylindrically braided fiber layer.

Each carrier 10, 11 is fitted with a bobbin (details not shown) on which the braided threads 12, 13 of the intermediate body 2 are wound. Each carrier 10, 11 also has a mechanism (details not shown) that uses a spring force or the like to generate tension for winding the braided threads 12, 13 around the mandrel 8. The movement directions of the carriers 10 and 11 are opposite to each other. That is, the carriers 10, 11 move in opposite directions along a figure-of-eight track 14 formed on the annular frame 7. The movement of the carriers 10, 11 forms a braided layer (3 to 5: Figure 1) on the mandrel 8.

For the sake of simplicity, only two sets of braids 12, 13 are shown in FIG. 2, but the corresponding braids are supplied from the adjacent sets of carriers 10, 11 on the annular frame 7 to the braiding position on the mandrel 8. Also, in FIG. 2, the number of carriers 10, 11 on the annular frame 7 is assumed to be 36, but the number of carriers 10, 11 can be arranged corresponding to the number of braids required depending on the size and shape of the intended telescope barrel parts. Note that a configuration in which multiple pipe bodies 15 are arranged in a ring shape on the annular frame 7, and braids are supplied from these pipe bodies 15 toward the mandrel 8 to form a cylindrically braided fiber layer 16 may also be used.

The fiber layer 16, which is wound around the mandrel 8 and assembled into a cylindrical shape, is heated using a heating means (such as a heater) (not shown), and if necessary, pressure is applied using an autoclave or the like to sinter and solidify the impregnated resin. At this time, molding pressure can be applied by pressing the outer mold or by the tension of the metal tape or the like. This sintering process advances the degree of impregnation of the carbon fiber and thermoplastic resin in the intermediate body 2, and then cooling, core removal from the mandrel 8, cutting of the ends, and the like are performed to manufacture the cylindrical body 1 as a lens barrel part. In this embodiment, since a thermoplastic resin (polycarbonate) is used as the impregnated resin, there is an advantage that the sintering process time is shorter than that of, for example, a thermosetting resin, and productivity can be improved. In order to smoothly core the cylindrical body 1 from the mandrel 8, a release agent can be applied to the mandrel in advance, or a surface treatment such as hard Cr plating or polytetrafluoroethylene film formation can be performed.

Figures 3(a) and (b) show a structure in which a ring-shaped resin part is provided as a covering part 17 at the end part 18 of the cylindrical body 1 as a lens barrel part configured as described above. The covering part 17 constitutes, for example, a mechanism or part thereof for fixing the cylindrical body 1 to another lens barrel part, or, if the cylindrical body 1 is a lens hood or the like, for attaching and detaching it to and from the other lens barrel part.

In the structure shown in Figures 3(a) and (b), at least one end 18 of the cylindrical body 1 is covered with a resin part formed as a covering portion 17. The covering portion 17 can be formed, for example, by insert injection molding a thermoplastic resin. For example, the cylindrical body 1 manufactured as described above is inserted into an injection molding die, and a thermoplastic resin containing fibers is injection molded to form the covering portion 17, which is integrated with the cylindrical body 1. This insert molding process is shown in detail in Figure 6, which will be described later.

In order to obtain sufficient strength for use as a fixing part or a detachable part of a telescope tube component, the covering part 17 is preferably made of a thermoplastic resin containing fibers. For example, the thermoplastic resin that constitutes the covering part 17 may be polycarbonate. In the case of polycarbonate, due to its own excellent impact resistance, it is possible to obtain a telescope tube component with improved toughness in the mounting part formed by the covering part 17.

By forming the covering portion 17 on the end portion 18 of the cylindrical body 1, it is possible to provide the lens barrel components with rings and other parts for use as attachments or detachable parts, which cannot be created during the weaving or solidification process of the cylindrical body 1. In addition, by using a thermoplastic resin containing fiber, the strength of the attachment portion and other parts formed by the covering portion 17 can be maintained. The fiber referred to here is not particularly limited as long as it is fibrous, but is generally short-fiber glass fiber or carbon fiber, or both, with a length of 1 mm or less. In this case, the fiber content is not particularly limited, but a range of about 20% to 40% is preferable.

The covering portion 17 can be molded into any shape and size depending on the performance, specifications, dimensions, etc. required for use as a fixing portion or a detachable portion of a lens barrel part. In the structure of Figures 3(a) and (b), the covering portion 17 is molded to cover the circumference of one end portion 18 of the cylindrical body 1, and a flange portion 17a protruding in the inward direction is formed on the inside of the end portion 18. When the cylindrical body 1 is the body of the lens barrel, the flange portion 17a is used as a support portion for an optical element or a focus ring. Also, for example, when the cylindrical body 1 is a lens hood that can be attached and detached to the main body of a photographic optical system, the resin part configured as the covering portion 17 can be used as part of a mechanism for attaching and detaching the lens hood.

Figures 4(a), (b), and (c) show different structures for providing a ring-shaped resin part as a covering part 17 on the end part 18 of the cylindrical body 1 as a lens barrel part configured as described above. Figures 4(a) and (b) are plan views and cross-sectional views in the same format as Figures 3(a) and (b), and Figure 4(c) is a cross-sectional view showing an enlarged view of the circled part in Figure 3(b).

In Figure 4, 20 is a circumscribing circle consisting of the thickest part of the cylindrical body 1, and the diameter of this circumference is diameter φ. The configuration in Figure 4 differs from Figure 3 in that, as shown in a particularly enlarged view in Figure 4(c), the circumference of the covering part 17 as a resin part is located inside the circumference of the cylindrical body 1 (circumscribing circle 20), and this part becomes the exposed part 21 of the end part 18 of the cylindrical body 1. The exposed amount 22 of the exposed part 21, i.e., the distance between the circumference of the covering part 17 and the circumference of the cylindrical body 1 (circumscribing circle 20), is set to a distance greater than the thickness distribution that occurs when the braided layers 3 and 5 described below are braided, and is at least 0.1 mm or more.

The reason for this structure is to facilitate insert molding of the covering portion 17. For example, when the braided layers 3 and 5 are weaved, unevenness occurs in the overlapping portions of the intermediate body 2, resulting in a distribution of thick and thin portions in the tubular body 1. For example, in FIG. 2, in the process of winding the fiber layer 16 around the mandrel 8, gaps are more likely to form between the braided threads of the intermediate body 2 in the braided layer 3 of the mandrel 8 than in the braided layer 5 on the inner side of the mandrel 8. In the case of a standard carbon fiber material, this variation in thickness of the tubular body 1 occurs by about 0.1 mm at the height of the circumferential surface of the tubular body 1.

Due to the characteristics of the braided layers 3 and 5, a part of the outer surface of the cylindrical body 1 is formed with a thinner thickness than the other parts. When the cylindrical body 1 is set in an injection molding die for insert molding of the covering portion 17, a gap is generated between the die and the part of the cylindrical body 1 where the thickness of the outer surface is thin. For example, as shown in FIG. 3, in a structure in which the exposed portion 21 does not exist at the end 18 of the cylindrical body 1, the cavity for the covering portion 17 and the gap between the die and the part of the cylindrical body 1 where the thickness of the outer surface is thin are connected. Therefore, when the resin of the covering portion 17 is injected into the cavity, the thermoplastic resin may enter the gap between the outer surface of the cylindrical body 1 and the die, and burrs may occur on the outer surface near the end 18 of the cylindrical body 1. In particular, if burrs occur on the outer surface of the cylindrical body 1 used as a lens barrel part as described above, the appearance quality of the lens barrel part will be deteriorated.

In response to this, as shown in FIG. 4, the shape of the covering portion 17 is determined so that the exposed portion 21 is formed at the end 18 of the cylindrical body 1 with an exposed amount 22 equal to or greater than the amount of thickness distribution (0.1 mm), and an injection molding die for insert molding the covering portion 17 is formed. As a result, even if there is variation in the thickness distribution of the peripheral surface of the end 18 of the cylindrical body 1 caused by the braiding of the braid layers 3 and 5, the exposed amount 22 of the exposed portion 21 is set to be greater than that. Therefore, the die reliably seals the edge portion 19 (FIG. 4(c)) of the peripheral surface of the end 18 of the cylindrical body 1 so that resin does not get into the peripheral surface. As a result, compared to the structure without the exposed portion 21 in FIG. 3, burrs caused by insert molding of the covering portion 17 on the peripheral surface of the end 18 of the cylindrical body 1 can be effectively suppressed. Therefore, it is possible to manufacture a lens barrel part with good dimensional accuracy and beautiful appearance.

<Embodiment 2>
Below, a modified example of the first embodiment will be described with reference to Figures 7(a), (b) and (c). Below, the same reference numerals are used for the same or equivalent configurations as those described above, and detailed description thereof will be omitted unless otherwise necessary. Figures 7(a) and (b) respectively show the side and cross section of the cylindrical body 1 having the completed covering portion 17, and Figure 7(c) shows in detail the cross section of the part circled in Figure 7(b).

In the configuration of FIG. 7, the covering portion 17 is also formed, for example, by insert injection molding a thermoplastic resin. For example, the cylindrical body 1 is inserted into an injection molding die, and the covering portion 17 is formed by injection molding a thermoplastic resin containing fibers, and is integrated with the cylindrical body 1. This insert molding process is shown in detail in FIG. 8, which will be described later.

This embodiment is characterized by the formation of a resin layer 40 on the surface of the cylindrical body 1. In FIG. 7(c), 40 denotes the resin layer of this embodiment, and 41 in the figure denotes an extremely thin resin layer with a very small thickness. This extremely thin resin layer 41 originates from the intermediate body 2 that constitutes the braided cord layers 3 and 5. That is, the resin that has been pre-impregnated into the intermediate body 2 is used to form an extremely thin resin layer 41 of 5 to 15 μm on the surface layer of the cylindrical body 1 through a solidification process. This extremely thin resin layer 41 serves to prevent strength deterioration caused by the carbon fiber material being exposed on the outer surface.

However, this extremely thin resin layer 41 is relatively fragile, and there is concern that it may affect the bond strength between the cylindrical body 1 and the covering portion 17. For example, it is conceivable that the extremely thin resin layer 41 may be divided due to the intrusion of carbon fibers that are unable to completely cover the extremely thin resin layer 41, resulting in a deterioration in the bond strength. In this regard, by providing the resin layer 40, the divisions in the extremely thin resin layer 41 can be filled, and the deterioration of the bond strength can be prevented.

In addition, for example, if the adhesion between the ultra-thin resin layer 41 and the carbon fiber is insufficient, the bonding strength may deteriorate. In this regard, the resin layer 40 provides an insulating effect, which causes heat storage from the resin during injection molding when forming the coating 17, increasing the activation energy between the ultra-thin resin layer 41 and the carbon fiber. Then, the pressure when forming the coating 17 can be used to firmly bond the ultra-thin resin layer 41 and the carbon fiber.

In this case, in order to utilize the insulating effect, the thickness of the resin layer 40 needs to be 50 μm or more and 200 μm or less. If the thickness of the resin layer 40 is 50 μm or less, the insulating effect cannot be exhibited, and heat from the resin escapes to the mold side through the cylindrical body 1, and the desired temperature rise cannot be expected between the ultra-thin resin layer 41 and the carbon fiber. Furthermore, if the thickness is 200 μm or more, the resin layer 40 is too thick, and due to its own heat capacity, the desired temperature rise cannot be expected between the ultra-thin resin layer 41 and the carbon fiber. Furthermore, if the thickness is 200 μm or more, it is not suitable from the perspective of weight reduction, which is the original purpose.

In consideration of the above, a thermoplastic resin such as polycarbonate is used as the resin for the resin layer 40. Also, considering the insert molding process of the covering portion 17, it is preferable that the resin layer 40 and the covering portion 17 are made of resins that have a high affinity with each other, and it is particularly preferable that they are the same resin. It is also desirable that the resin layer 40 and the resin that is pre-impregnated into the intermediate body 2 that constitutes the braided layers 3 and 5 have a high affinity with each other, and preferably are the same resin. By combining such materials, it is possible to increase the bonding strength between the resin layer 40 and the covering portion 17 and the ultra-thin resin layer 41.

In this embodiment, the resin layer 40 is polycarbonate. In applications such as this embodiment, the viscosity average molecular weight of this polycarbonate is preferably in the range of approximately 18,000 to 25,000. For example, if the viscosity average molecular weight of polycarbonate is 18,000 or less, the toughness decreases, and if it is 25,000 or more, the melt viscosity tends to be high, and there is a possibility that the bonding strength between the resin layer 40 and the ultra-thin resin layer 41 will deteriorate during the impregnation process.

As a method for forming the resin layer 40, for example, a film-like thermoplastic resin that will become the resin layer 40 is wrapped around the fiber layer 16 in which the intermediate body 2 is assembled in a cylindrical shape. Then, the intermediate body 2 and the wrapped thermoplastic resin are heated (and pressurized as necessary) to form the extremely thin resin layer 41 of 5 to 15 μm on the surface of the cylindrical body 1 and the resin layer 40. As a method for wrapping this film-like thermoplastic resin, for example, after manufacturing the fiber layer 16 in which the intermediate body 2 is assembled in a cylindrical shape, a winding method is given in which a filament of thermoplastic resin processed from a film into a tape shape is filament-wound. In addition, as another method, for example, after manufacturing the fiber layer 16 in which the intermediate body 2 is assembled in a cylindrical shape, a method may be used in which the thermoplastic resin film in a tape shape is wound around the fiber layer 16 in which the intermediate body 2 is assembled in a cylindrical shape.

As another method, after manufacturing a cylindrical body 1 with a 5-15 μm ultra-thin resin layer 41 formed on the surface, a filament of thermoplastic resin processed from a film into a tape is wound on the ultra-thin resin layer 41 by filament winding. After winding, the thermoplastic resin is heated (and pressurized as necessary) to form a resin layer 40 on the 5-15 μm ultra-thin resin layer 41 on the surface of the cylindrical body 1.

As another method, for example, after manufacturing a cylindrical body 1 with a 5-15 μm ultra-thin resin layer 41 formed on the surface, a tape-shaped thermoplastic resin film is wound around the cylindrical body 1 by weaving it onto the ultra-thin resin layer 41. Then, after winding, the thermoplastic resin is heated (and pressurized as necessary) to form a resin layer 40 on the 5-15 μm ultra-thin resin layer 41 on the surface of the cylindrical body 1.

Then, the cylindrical body 1 on which the resin layer 40 has been formed is inserted into a mold, and the coating portion 17 is formed on the resin layer 40 by injection molding, and they are integrated together. Alternatively, a method may be used in which the film that will become the resin layer 40 is wound to a specified thickness or more, the resin layer 40 is formed, and then the resin layer 40 is shaved to the specified thickness.

If the surface of the cylindrical body 1 has unevenness due to the assembly of the intermediate body 2, for example, when applying a coating for the purpose of heat insulation to the lens barrel parts, the appearance quality may be reduced. However, as in this embodiment, the resin layer 40 is formed by wrapping a film that becomes the resin layer 40 with a thickness of 50 μm or more and 200 μm or less, or by further grinding the resin layer 40 to a specified thickness, the resin layer 40 other than the coating part 17 to be painted can be finished smoothly. This can significantly improve the appearance quality of the paint. It is also possible to adopt a method in which the resin layer 40 is formed to a specified thickness only in the area where the coating part 17 is formed, and the other resin layer 40 is ground down to a specified thickness or less. This maintains the thickness of the resin layer 40 due to the bonding strength, while the other appearance quality parts can be ground down to a smooth surface, and also contributes to weight reduction.

Example 1
Figures 5(a), (b), and (c) show the configuration of the covering portion 17 which is further modified from Figures 4(a), (b), and (c). Figures 6(a) to (d) show the state of insert molding of the covering portion 17 into the cylindrical body 1. Below, the configuration of the cylindrical body 1 and the details of the manufacturing process will be described in detail with reference to Figures 5 and 6.

In Figure 5(a), 23 indicates the braiding angle of the intermediate body 2 that constitutes the braided layer (3 or 5). In other words, the intermediate bodies 2 that constitute the braided layers 3 and 5 are braided in a direction inclined at the braiding angle 23 to the axial direction of the tubular body. As shown in Figure 5(b) or (c), the layered structure of the tubular body 1 is a three-layer structure consisting of a braided layer 3, a unidirectional prepreg sheet layer 4, and a braided layer 5 from the inner periphery, as described above.

The intermediate 2 for braiding the braided layer (3 or 5) is, for example, a prepreg sheet made by electrostatically attaching thermoplastic resin powder to an opened carbon fiber sheet material and heating it, and then cutting it into a tape shape. The sheet material for the unidirectional prepreg sheet layer 4 is, for example, wrapped around the braided layer 5 before braiding the third braided layer 3, and is positioned between the layers as the braided layer 3 is braided.

The VF of the intermediate 2 of the braided layer (3 or 5) and the unidirectional prepreg sheet are both set to, for example, 50%, and the impregnating resin for both is polycarbonate with a viscosity average molecular weight of 20,000. The theoretical thickness of the intermediate 2 when 100% impregnated is 0.115 mm, and the density of the thermoplastic resin in the semi-impregnated state of the intermediate 2 when the braided layers 3 and 5 are formed is set to 50% to 60%. The cylindrical body 1, which is made of three layers of braided layer 3, unidirectional prepreg sheet layer 4, and braided layer 5 made of such materials and manufactured by the process described below, is assumed to have a theoretical thickness of approximately 0.575 mm (Table 1 below).

The braiding angle 23 of the intermediate body 2 and the orientation direction of the carbon fibers in the unidirectional prepreg sheet are determined taking into consideration the strength and rigidity in the completed state when used as a lens barrel part. For example, different braiding angles (23) may be used, such as a braiding angle of 30° for the inner braided layer 3 and a braiding angle of 60° for the outer braided layer 5. The orientation direction of the carbon fibers in the unidirectional prepreg sheet is made to approximately match the direction along the cylindrical axis of the tubular body 1.

The cylindrically assembled fiber layer 16 (FIG. 2) is braided (first step) on the mandrel 8 using the braiding device 6 in FIG. 2, and then heated using a heating means (such as an autoclave, not shown) to solidify the impregnated thermoplastic resin (second step). Although this differs depending on the specifications of the lens barrel components that make up the cylindrical body 1, for example, a cylindrical mandrel 8 with a diameter of about Φ69 mm is used. In addition, the mandrel 8 is given a surface treatment, such as polytetrafluoroethylene plating, to facilitate easy demolding.

In the solidification process, molding pressure is applied from the outer periphery of the cylindrically assembled fiber layer 16. For example, applying pressure by the tension of wrapping a metal tape can promote the impregnation, bonding, and solidification of the carbon fibers and thermoplastic resin in the intermediate body 2. In addition, in the solidification process, it is also possible to use inner and outer molds of a shape different from the mandrel 8 to form the final shape of the cylindrical body 1 (for example, a truncated pyramid shape).

Then, the mandrel 8 and the cylindrical body 1 are cooled, the cylindrical body 1 is removed from the mandrel 8, and the end portion 18 is appropriately cut and shaped to complete the cylindrical body 1.

The properties of the cylindrical bodies manufactured under the above conditions and the comparative examples are shown in Table 1. Table 1 shows the results of compression tests conducted in the cylindrical axial direction on the cylindrical bodies manufactured under the above conditions (left side of Table 1: Examples) and the cylindrical bodies (right side of Table 1: Comparative Examples).

The cylindrical body of the embodiment (left side of Table 1) is composed of the braided layers 3 and 5 and the unidirectional prepreg sheet layer 4 (Fig. 5 (b) and (c)). The cylindrical body of the comparative example (right side of Table 1) is made by repeatedly stacking and solidifying six layers of unidirectional prepreg sheets impregnated with hydrogenated bisphenol A type epoxy resin while changing the orientation direction of the fibers in the cylindrical axial direction and circumferential direction of the cylindrical body. Unlike the cylindrical body of the present embodiment described above, the cylindrical body of the comparative example (right side of Table 1) does not use a cylindrical braided layer, but is formed by wrapping a unidirectional prepreg sheet. The theoretical thickness of the cylindrical body of the comparative example (right side of Table 1) is 0.84 mm. In contrast, the theoretical thickness of the cylindrical body of the present embodiment (left side of Table 1) is 0.575 mm, which is thinner and therefore lighter. Moreover, the cylindrical body of the present embodiment (left side of Table 1) is thinner than the cylindrical body of the comparative example (right side of Table 1), but it is able to achieve a compressive fracture strength equal to or greater than that of the comparative example.

In the following, referring to FIG. 6, a detailed description will be given of a configuration for insert-molding a resin part as the coating 17 on the end 18 of the cylindrical body 1 that has undergone the solidification process, and an example of the insert molding process. Here, as described in FIG. 5, a coating 17 is formed having an exposed portion 21 with an exposure amount 22 of 0.1 mm from a circumscribed circle 20 consisting of the maximum thickness. In this example, as shown in FIGS. 5(b) and (c), the edge portion 19 on the end 18 of the cylindrical body 1 is lightly chamfered to 0.05 mm or less. The chamfering of this edge portion 19 can be formed, for example, by cutting before the coating 17 is insert-molded.

Figures 6(a) to (d) show, in the order of steps, cross sections of a mold for insert-molding a resin part as a covering part 17 onto the end part 18 of the cylindrical body 1 that has undergone a solidification process. In Figures 6(a) to (d), the insert-molding mold 24 is made up of a fixed mold 25 and a movable mold 26, and is mounted on an injection molding machine 30.

As shown in Fig. 6(a) and (b), the fixed mold 25 and the movable mold 26 have a cavity 28 formed to accommodate the solidified cylindrical body 1. As shown in Fig. 6(a), the solidified cylindrical body 1 is accommodated in this cavity 28, and the mold is clamped as shown in Fig. 6(b). In this state, a mold shape 27 for molding the covering portion 17 is provided at the position of the fixed mold 25 corresponding to the end portion 18 of the cylindrical body 1, with a structure as shown in Fig. 5(b) and (c). This mold shape 27 is shaped to seal the edge of the cylindrical body 1 in the fixed mold 25 so that the exposed portion 21 is formed. This mold shape 27 can effectively prevent the resin from overflowing from the cavity 28 on the inner periphery side of the end portion 18 of the cylindrical body 1 toward the outer periphery of the cylindrical body 1 and becoming a burr when the molding resin 32 is poured as shown in Fig. 6(c).

In the insert molding process of the covering portion 17, the cylindrical body 1 is first set in the cavity 28 of the movable die 26 of the insert molding die 24 as shown in FIG. 6(a), and then the fixed die 25 and the movable die 26 of the insert molding die 24 are clamped together as shown in FIG. 6(b).

As shown in FIG. 6(c), the injection molding machine 30 injects and fills the molten molding resin 32 through the spool, runner, and gate (31: FIG. 6(a)) of the insert molding die 24. In this embodiment, the fixed die 25 seals the end 18 so that the exposed portion 21 is formed at the end 18 of the cylindrical body 1 by the mold shape 27, so that the molding resin 32 is prevented from leaking from the cavity 28 toward the outer periphery of the cylindrical body 1 and causing burrs. For example, polycarbonate containing 30% glass fiber is used for the molding resin 32. After that, the molding resin 32 is hardened through mold cooling, etc., so that the cylindrical body 1 and the molding resin 32 are integrated, and the ring- and flange-shaped covering portion 17 as described above can be molded at the end 18 of the cylindrical body 1.

Then, the injection molding machine 30 is driven to separate the fixed mold 25 and the movable mold 26 as shown in FIG. 6(d), and the cylindrical body 1 and the portion of the runner 33 molded within the gate by the molding resin 32 are demolded by a demolding means (not shown). In this way, it is possible to manufacture a lens barrel part consisting of the cylindrical body 1 equipped with a resin part (coating portion 17), which has a high-quality appearance without burrs on the outer periphery.

Example 2
As another example, the configuration and manufacturing process of the cylindrical body 1 described as the second embodiment will be described in detail with reference to Figs.

As shown in Figure 7 (b) or (c), the laminated structure of the cylindrical body 1 is the same as described above, consisting of three layers from the inner circumference side: braided layer 3, unidirectional prepreg sheet layer 4, and braided layer 5. The intermediate body 2 for braiding the braided layer (3 or 5) is made of a prepreg sheet cut into a tape shape, which is made by electrostatically attaching thermoplastic resin powder to an opened carbon fiber sheet material and heating it.

The sheet material for the unidirectional prepreg sheet layer 4 is, for example, wrapped around the braided layer 5 before the third braided layer 3 is assembled, and is positioned between the layers while the braided layer 3 is being assembled. The VF of the intermediate 2 of the braided layer (3 or 5) and the unidirectional prepreg sheet are both, for example, 50%, and the impregnating resin for both is polycarbonate with a viscosity average molecular weight of 20,000.

The theoretical thickness of the intermediate body 2 when 100% impregnated is 0.115 mm, and the density of the thermoplastic resin in the semi-impregnated state of the intermediate body 2 when the braided layers 3 and 5 are formed is set to 50% to 60%. The cylindrical body 1, which is made of three layers of braided layer 3, unidirectional prepreg sheet layer 4, and braided layer 5 made of such materials and manufactured by the process described below, is expected to have a theoretical thickness of approximately 0.575 mm.

The braiding device 6 in Figure 2 is used to braid (first step) the cylindrically braided fiber layer 16 (Figure 2) onto the mandrel 8.

Next, a tape-shaped polycarbonate film is placed on one of the carriers 10 of the braiding device 6, and filament winding is performed to wrap the polycarbonate film around the cylindrically assembled fiber layer 16.

The polycarbonate film used was pre-slit to a width of 5 mm. The viscosity average molecular weight of the polycarbonate film used was 20,000.

Next, the cylindrically assembled fiber layer 16 wrapped with the polycarbonate film is heated using a heating means to solidify the thermoplastic resin impregnated therein (second process). Although this differs depending on the specifications of the lens barrel components that make up the cylindrical body 1, for example, a cylindrical mandrel 8 with a diameter of about Φ69 mm is used. In addition, the mandrel 8 is given a surface treatment, such as polytetrafluoroethylene plating, to facilitate demolding.

In the solidification process, molding pressure is applied from the outer periphery of the polycarbonate film wrapped around the cylindrically assembled fiber layer 16. For example, pressure is applied by the tension of wrapping a metal tape, which promotes the impregnation, bonding, and solidification of the carbon fibers and thermoplastic resin in the intermediate body 2, while integrating them with the polycarbonate film wrapped around the surface.

Then, the mandrel 8 and the cylindrical body 1 are cooled, and the cylindrical body 1 is de-cored from the mandrel 8, and the end portion 18 is appropriately cut and shaped to complete the cylindrical body 1 with a resin layer 40 formed on the surface.

At that time, the resin layer 40 on the surface was ground to a predetermined thickness. Below, with reference to Figure 8, a detailed explanation will be given of the configuration for insert-molding a resin part as the coating portion 17 into the resin layer 40 on the surface of the cylindrical body 1 that has undergone the solidification process, and an example of the insert molding process.

Here, the thickness 42 of the covering portion 17 shown in Figure 7 is set to 1.5 mm. Figures 8(a) to (d) show, in the order of steps, cross sections of a mold for insert molding a resin part as the covering portion 17 into the resin layer 40 on the surface of the cylindrical body 1 that has undergone a solidification process. In Figures 8(a) to (d), the insert molding mold 24 is made up of a fixed mold 25 and a movable mold 26, and is attached to an injection molding machine 30.

As shown in Figs. 8(a) and (b), a cavity 28 is formed in the fixed die 25 and the movable die 26 to accommodate the solidified cylindrical body 1. As shown in Fig. 8(a), the solidified cylindrical body 1 is accommodated in this cavity 28, and the die is clamped as shown in Fig. 8(b). In this state, a die shape 27 for forming the covering portion 17 is provided.

In the insert molding process of the covering portion 17, first, as shown in FIG. 8(a), the cylindrical body 1 on which the resin layer 40 has been formed is set in the cavity 28 of the movable die 26 of the insert molding die 24, and then, as shown in FIG. 8(b), the fixed die 25 and the movable die 26 of the insert molding die 24 are clamped together. Then, as shown in FIG. 8(c), the molten molding resin 32 is injected and filled through the spool, runner, and gate (31: FIG. 8(a)) of the insert molding die 24.

The molding resin 32 is made of, for example, polycarbonate containing 30% glass fiber.
Thereafter, the molded resin 32 is hardened after cooling the mold, etc., so that the cylindrical body 1 and the molded resin 32 are integrated, and the covering portion 17 as described above can be molded on the resin layer 40 of the cylindrical body 1.

Then, the injection molding machine 30 is driven to separate the fixed mold 25 and the movable mold 26 as shown in FIG. 8(d), and a demolding means (not shown) is used to demold the cylindrical body 1 and the portion of the runner 33 molded within the gate by the molding resin 32. In this way, a lens barrel part consisting of the cylindrical body 1 equipped with a resin part (coating portion 17) is obtained. Then, by painting the surface, a lens barrel part with a high-quality appearance can be manufactured.

In addition, for a given thickness of the resin layer 40, the actual strength relative to the thickness cannot be measured in the form of the cylindrical body 1, so a tensile test was performed to confirm the joint strength. Figures 9(a) to (c) show the shape of the sample used in this tensile test. Figure 9(a) is a plan view of the sample, Figure 9(b) is a cross-section of the joint, and Figure 9(c) shows the cross-sectional structure of the circled part in Figure 9(b) in detail. In Figures 9(a) to (c), 50 is an experimental piece, 51 is a continuous carbon fiber reinforced resin molded body with a resin layer 40 (Figures 9(b) and 9(c)), and 52 and 53 are the length and width of the continuous carbon fiber reinforced resin molded body 51. In addition, 54 and 55 in the figure indicate the length and width of the coating part 17, and 56 and 57 in the figure indicate the length and width of the joint between the continuous carbon fiber reinforced resin molded body 51 and the coating part 17.

Here, the lengths 52 and 54 are both 75 mm, and the widths 53 and 55 are both 25 mm. The length 56 of the joint is 25 mm, and the width 57 is 25 mm. The laminated structure of the continuous carbon fiber reinforced resin molded body 51 is a three-layer structure consisting of a twill layer 58, a unidirectional prepreg sheet layer 59, and a twill layer 60. The VF of the twill layer (58 or 60) and the unidirectional prepreg sheet is, for example, both 50%, and the impregnated resin in both is polycarbonate with a viscosity average molecular weight of 20,000. The theoretical thickness of the intermediate body 2 when 100% impregnated is 0.115 mm, and the density of the thermoplastic resin in the semi-impregnated state of the intermediate body 2 when the twill layers 58 and 60 are formed is set to 50% to 60%.

The continuous carbon fiber reinforced plastic molding 51 is made of three layers of material, a twill weave layer 58, a unidirectional prepreg sheet layer 59, and a twill weave layer 60, and is manufactured by the process described below. The theoretical thickness of the molding is assumed to be approximately 0.575 mm.

The twill layer was prepared by twill-weaving the intermediate 2, and a unidirectional prepreg sheet layer 59 was placed between the twill layers 58 and 60, and a polycarbonate film was laminated on the twill layer 58 side. The viscosity average molecular weight of the polycarbonate film used was 20,000.

Next, the continuous carbon fiber reinforced resin molded body 51 with the polycarbonate film laminated thereon is heated using a heating means to solidify the thermoplastic resin impregnated therein (second process). In this solidification process, molding pressure is applied to the continuous carbon fiber reinforced resin molded body 51 using a flat mold and a press device (not shown).

By applying pressure, the carbon fibers in the intermediate body 2 can be integrated with the polycarbonate film laminated on the surface while promoting the impregnation, bonding, and solidification of the thermoplastic resin.
Thereafter, the mold and the continuous carbon fiber reinforced resin molded body 51 are cooled, and then the mold is released and cut to complete the continuous carbon fiber reinforced resin molded body 51 having the surface resin layer 40 formed thereon. At this time, the surface resin layer 40 is processed to a predetermined thickness by grinding.

Then, a resin part was insert-molded as a covering part 17 into the resin layer 40 on the surface of the continuous carbon fiber reinforced resin molded body 51 that had undergone the solidification process, to create an experimental piece 50 as shown in FIG. 9. Here, the thickness of the covering part 17 shown in FIG. 9 was set to 1.5 mm.

The characteristics of the bonding strength depending on the thickness of the resin layer 40 of the continuous carbon fiber reinforced resin molded body 51 manufactured under the above conditions are shown in Table 2 below. This Table 2 shows the results of a tensile test performed on the experimental piece 50 (Example) manufactured under the above conditions. At this time, an electromechanical universal material testing machine manufactured by Instron was used, and the experimental piece 50 was chucked at both ends of 25 mm with the testing machine and the tensile test was performed. In Table 2, the thickness of the resin layer 40 is a value obtained by subtracting the thickness dimension calculated from the theoretical thickness of the continuous carbon fiber reinforced resin molded body without the resin layer 40 from the actual thickness dimension of the continuous carbon fiber reinforced resin molded body 51 with the resin layer 40.

As shown in Table 2, if the thickness of the resin layer 40 is between 50 μm and 200 μm, a tensile strength of 5 MPa or more can be obtained. It can also be seen that a structure in which a resin layer 40 having a thickness of 50 μm or more and 200 μm or less is provided on the surface of the cylindrical body is preferable. With such a structure, a lens barrel part with excellent bonding strength can be obtained.

1...Cylindrical body, 2...Intermediate body, 3, 5...Braid layer, 4...Unidirectional prepreg sheet layer, 6...Braiding device, 7...Annular frame, 8...Mandrel, 9...Through hole, 10, 11...Carrier, 12, 13...Braid, 14...Figure-of-eight track, 15...Pipe body, 17...Covering portion, 18...End portion, 19...Edge portion, 20...Circumscribed circle, 21...Exposed portion, 22...Exposed amount, 23...Braiding angle, 24...Insert molding die, 25...Fixed die, 26...Movable die, 28...Cavity, 40...Resin layer, 41...Ultra-thin resin layer.

A first aspect of the present invention is an optical device including an optical element and a barrel that holds or adjusts the optical element , the optical device comprising a cylindrical body that is a barrel component , the cylindrical body including a cylindrical first carbon fiber layer and a cylindrical second carbon fiber layer located on the outer circumferential side of the cylindrical body with respect to the first carbon fiber layer, the first carbon fiber layer being a braided layer in which a plurality of carbon fibers of the first carbon fiber layer are braided to cross each other and form a cylindrical shape and are provided so as to be endless in the circumferential direction of the cylindrical body, the first carbon fiber layer being impregnated with resin, the second carbon fiber layer being a braided layer in which a plurality of carbon fibers of the second carbon fiber layer are braided to cross each other and form a cylindrical shape and are provided so as to be endless in the circumferential direction of the cylindrical body , and the second carbon fiber layer being impregnated with resin .
A second aspect of the present invention is a manufacturing method for an optical device including an optical element and a lens barrel for holding or adjusting the optical element, wherein a manufacturing process for a tubular body which is a lens barrel component of the optical device includes a step of forming a first carbon fiber layer impregnated with a first thermoplastic resin on a mandrel, a step of forming a second carbon fiber layer impregnated with a second thermoplastic resin on the first carbon fiber layer on the mandrel, and a step of heating the first thermoplastic resin and the second thermoplastic resin to bond the first carbon fiber layer and the second carbon fiber layer together. and in the step of forming the first carbon fiber layer, the first carbon fiber layer is a braided layer in which the multiple carbon fibers of the first carbon fiber layer are braided into a cylindrical shape at an angle with respect to the axial direction of the cylindrical body and are provided endless in the circumferential direction of the cylindrical body, and in the step of forming the second carbon fiber layer, the second carbon fiber layer is a braided layer in which the multiple carbon fibers of the second carbon fiber layer are braided into a cylindrical shape at an angle with respect to the axial direction of the cylindrical body and are provided endless in the circumferential direction of the cylindrical body .

Claims (20)

An optical device configured to be detachably attached to an imaging device,
a cylindrical body including a first carbon fiber layer which is a cylindrically braided layer, and a cylindrical second carbon fiber layer which is located on the outer circumferential side of the cylindrical body with respect to the first carbon fiber layer, the first carbon fiber layer and the second carbon fiber layer being bonded together by a thermoplastic resin which is an integrated combination of a first thermoplastic resin impregnated into the first carbon fiber layer and a second thermoplastic resin impregnated into the second carbon fiber layer;
an optical element;
The first carbon fiber layer is provided so that the carbon fibers of the first carbon fiber layer are inclined with respect to the axial direction of the cylindrical body and woven in a twill pattern, and are endless in the circumferential direction of the cylindrical body,
The second carbon fiber layer is a sheet-shaped carbon fiber layer.
An optical instrument characterized by: An optical device configured to be detachably attached to an imaging device,
a cylindrical body including a first carbon fiber layer which is a cylindrically braided layer, and a cylindrical second carbon fiber layer located on the inner circumferential side of the cylindrical body with respect to the first carbon fiber layer, the first carbon fiber layer and the second carbon fiber layer being bonded together by a thermoplastic resin in which a first thermoplastic resin impregnated in the first carbon fiber layer and a second thermoplastic resin impregnated in the second carbon fiber layer are integrated;
an optical element;
The first carbon fiber layer is provided so that the carbon fibers of the first carbon fiber layer are inclined with respect to the axial direction of the cylindrical body and woven in a twill pattern, and are endless in the circumferential direction of the cylindrical body,
The second carbon fiber layer is a sheet-shaped carbon fiber layer.
An optical instrument characterized by: The cylindrical body is formed by integrally bonding the first carbon fiber layer impregnated with the first thermoplastic resin and the second carbon fiber layer impregnated with the second thermoplastic resin by heat treatment under pressure using an outer mold.
3. The optical device according to claim 1 or 2. The second carbon fiber layer is a sheet-shaped carbon fiber layer along the circumferential direction of the cylindrical body, the sheet-shaped carbon fiber layer being provided so as to have a seam in the circumferential direction of the cylindrical body.
4. An optical instrument according to claim 1, wherein the optical instrument is a casing. A first resin layer having a thickness of 5 μm to 15 μm is provided on a side of the second carbon fiber layer opposite to the first carbon fiber layer and on a side of the first carbon fiber layer opposite to the second carbon fiber layer,
5. An optical instrument according to claim 1, wherein the optical instrument is a casing. The carbon fibers of the second carbon fiber layer are oriented in the axial direction of the cylindrical body, and do not include any carbon fibers inclined with respect to the axial direction of the cylindrical body.
6. An optical instrument according to claim 1, wherein the optical instrument is a casing. a third carbon fiber layer which is a cylindrical braided layer located on the opposite side of the second carbon fiber layer from the first carbon fiber layer, and the second carbon fiber layer and the third carbon fiber layer are bonded to each other by a resin;
7. An optical instrument according to claim 1, wherein the optical instrument is a casing. The carbon fibers of the third carbon fiber layer are arranged at an angle to the axial direction of the cylindrical body.
8. An optical instrument according to claim 7. A braiding angle of the carbon fibers in the first carbon fiber layer with respect to the axial direction of the tubular body is different from a braiding angle of the carbon fibers in the third carbon fiber layer with respect to the axial direction of the tubular body.
9. An optical instrument according to claim 7 or 8. the third carbon fiber layer being a twill layer;
10. Optical instrument according to claim 7, characterized in that A ring-shaped resin coating portion is attached to an end of the cylindrical body.
11. An optical instrument according to claim 1 . The resin of the coating portion is a thermoplastic resin containing fibers.
12. The optical instrument according to claim 11. The peripheral surface of the cylindrical body is located 0.1 mm or more inside the peripheral surface of the covering portion, and the end of the cylindrical body forms an exposed portion exposed from the covering portion in that portion.
13. An optical instrument according to claim 11 or 12. The thermoplastic resin is polycarbonate.
14. Optical instrument according to any one of claims 1 to 13. The optical element includes at least one of a lens or a mirror.
15. Optical instrument according to any one of claims 1 to 14. The cylindrical body constitutes a body part of a lens barrel that holds or adjusts an optical element.
16. Optical instrument according to any one of claims 1 to 15. The optical device according to any one of claims 1 to 16, characterized in that the cylindrical body is a lens barrel part that constitutes at least one of a lens hood, an outer barrel, an inner barrel, and a focus ring, and is configured to be detachable from the imaging device. forming a first carbon fiber layer impregnated with a first thermoplastic resin by crossing and braiding a plurality of carbon fibers on a mandrel into a cylindrical shape;
forming a second layer of carbon fiber on the mandrel, the second layer being impregnated with a second thermoplastic resin;
and bonding the first carbon fiber layer and the second carbon fiber layer with a thermoplastic resin by heat treating the first carbon fiber layer and the second carbon fiber layer.
The bonding step is carried out under pressure using an outer mold,
In the step of forming the first carbon fiber layer, the first carbon fiber layer is provided so that the carbon fibers of the first carbon fiber layer are woven in a twill pattern inclined with respect to the axial direction of the cylindrical body and are endless in the circumferential direction of the cylindrical body,
A method for manufacturing a cylindrical body, wherein in the step of forming the second carbon fiber layer, the second carbon fiber layer is a sheet-shaped carbon fiber layer. The method for manufacturing a cylindrical body described in claim 18, characterized in that the degree of impregnation of the first carbon fiber layer with the first thermoplastic resin and the degree of impregnation of the second carbon fiber layer with the second thermoplastic resin are such that the resin density is 40% to 70%. A step of producing a cylindrical body by the production method according to claim 18 or 19;
and mounting an optical element on the cylindrical body.
A manufacturing method for manufacturing an optical device configured to be detachably attached to an imaging device.

Images