JP2023031426A - Mold assembly used for manufacturing fiber-reinforced resin structure, and method for manufacturing fiber-reinforced resin structure - Google Patents

Abstract

To provide a method for manufacturing a fiber-reinforced resin structure using a mold assembly capable of easily pressurizing an inner space of a mandrel in a mold.SOLUTION: A method for manufacturing a fiber-reinforced resin structure comprises: a mold assembly preparation step S200 for preparing a mold assembly; an intermediate body installation step S201 for installing an intermediate body being an intermediate body of the fiber-reinforced resin structure, and provided with a pressure introduction part for introducing a pressure into the intermediate body, in an inner space of a mold so as to communicate between the inside of the intermediate body and the outside of the mold via the pressure introduction part; an expansion step S202 for expanding the intermediate body by applying an inner pressure from the pressure introduction part to the intermediate body; and a molding step S203 for flowing resin into the mold to mold the fiber-reinforced resin structure.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a mold device and a method for manufacturing a fiber-reinforced resin structure used for manufacturing a fiber-reinforced resin structure.

Conventionally, as a method for manufacturing a fiber-reinforced resin structure, a prepreg in which carbon fiber is impregnated with a thermosetting resin is wound around a mandrel by the FW (filament winding) method to form an intermediate body of a fiber-reinforced resin structure in advance. Then, it is known to cure this by autoclave treatment (see, for example, Patent Document 1). In addition, as a method for manufacturing a fiber-reinforced resin structure, an intermediate body in which resin-unimpregnated carbon fibers are wound around a mandrel is placed in a mold, and the carbon fibers are impregnated with a thermosetting resin in the mold, An RTM (Resin Transfer Molding) method for curing this is disclosed (see Patent Document 2, for example). According to the manufacturing method described in Patent Document 2, compared with the manufacturing method described in Patent Document 1, the dimensional accuracy of the obtained molded product can be further improved.

JP 2003-127257 A JP-A-8-323870

However, in the manufacturing method of Patent Document 2, when the intermediate is placed in the mold, the carbon fibers may get caught in the joints between the split molds that constitute the mold. Therefore, in order to prevent the carbon fiber from getting caught in the split mold, after placing an intermediate body of a size that forms a clearance with the inner wall of the mold inside the mold, the internal pressure of the mandrel is increased. A possible manufacturing method is to expand the intermediate in a mold, fill the mold with a thermosetting resin, and cure the resin.
According to such a manufacturing method, it is possible to obtain a high-quality fiber-reinforced resin structure without generating burrs or the like due to the carbon fiber being caught, and at the same time, the expanded intermediate fills the mold with resin. By reducing the amount, it is possible to reduce the weight of the resulting fiber-reinforced resin structure.
Therefore, the intermediate having fibers can be expanded in the mold with a simple structure, and the resin can be effectively filled between the mold and the intermediate without leaking out of the mold. However, such a technique has not yet been specifically known.

An object of the present invention is to provide a mold apparatus capable of expanding a fiber-containing intermediate in a mold with a simple structure and effectively filling a space between the mold and the intermediate with a resin. and a method for manufacturing a fiber-reinforced resin structure using this mold apparatus.

The mold apparatus of the present invention, which has solved the above-mentioned problems, has an opening surface on the outside in the axial direction of the internal space of the mold in which the intermediate body of the fiber-reinforced resin structure composed of the mandrel on which the fibers are placed is arranged. and a sealing member arranged between the intermediate body and the mold so as to be adjacent to the opening surface when the intermediate body is arranged in the internal space of the mold. characterized by

Further, the method for manufacturing a fiber-reinforced resin structure according to the present invention, which solves the above problems, includes a mold device preparation step for preparing the mold device, and the fiber is installed after the mold device preparation step. The intermediate body of the fiber-reinforced resin structure made of the mandrel and provided with a pressure introduction part for introducing pressure into the intermediate body is placed between the inside of the intermediate body and the metal. an intermediate body installation step of installing the intermediate body in the internal space of the mold so as to communicate with the outside of the mold through the pressure introduction portion; and after the intermediate body installation step, applying an internal pressure from the pressure introduction portion to the intermediate body. characterized by having an expansion step of expanding the intermediate body by applying the intermediate, and a molding step of forming a fiber-reinforced resin structure by flowing a resin into the mold after the expansion step. do.

ADVANTAGE OF THE INVENTION According to the present invention, a mold device capable of expanding a fiber-containing intermediate in a mold with a simple structure and effectively filling a space between the mold and the intermediate with a resin. , and a method for manufacturing a fiber-reinforced resin structure using this mold apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS It is structure explanatory drawing of the structure made from a fiber reinforced resin produced with the manufacturing method of 1st embodiment of this invention. FIG. 4 is a process explanatory diagram of fabricating a fiber-reinforced resin structure by the manufacturing method of the first embodiment of the present invention. FIG. 3 is a vertical cross-sectional view of a mandrel prepared in a mandrel preparation process that constitutes the FW (Filament Winding) process shown in FIG. 2 ; FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3 and a transverse cross-sectional view of the mandrel. FIG. 3 is a vertical cross-sectional view of a connected body in which a metal member is connected to a mandrel in a metal member connecting step that constitutes the FW step shown in FIG. 2 ; FIG. 3 is a schematic diagram showing how a first fiber layer is formed on a mandrel in a fiber installation process that constitutes the FW process shown in FIG. 2 ; FIG. 3 is a schematic diagram showing how a second fiber layer is formed on a mandrel in a fiber installation process that constitutes the FW process shown in FIG. 2 ; FIG. 3 is a schematic diagram showing how a third fiber layer is formed on a mandrel in a fiber installation process that constitutes the FW process shown in FIG. 2 ; FIG. 3 is a configuration explanatory diagram of a mold device prepared in a mold device preparation process that constitutes the RTM (Resin Transfer Molding) process shown in FIG. 2 ; FIG. 3 is a schematic diagram showing how the internal space of the mandrel is pressurized in the mandrel expansion process that constitutes the RTM process shown in FIG. 2 ; FIG. 3 is a schematic diagram showing a state of an intermediate after undergoing a mandrel expansion process that constitutes the RTM process shown in FIG. 2 ; FIG. 3 is a schematic diagram showing a state in which a preformed body is obtained in a mold in a molding process that constitutes the RTM process shown in FIG. 2; FIG. 3 is a cross-sectional view of the preform after a mandrel removal step that constitutes the RTM step shown in FIG. 2; FIG. 4 is a process explanatory drawing for fabricating a fiber-reinforced resin structure by the manufacturing method of the second embodiment of the present invention. FIG. 12 is an enlarged cross-sectional view of a lower portion of the mold device used in the manufacturing method of the second embodiment shown in FIG. 11; FIG. 5 is an enlarged cross-sectional view of a lower part of the mold device, showing a modified example of the pressure introducing portion that constitutes the mold device.

Next, a method for manufacturing a fiber-reinforced resin structure according to a mode (embodiment) for carrying out the present invention and a mold device used in this manufacturing method will be described in detail with appropriate reference to the drawings.
In the manufacturing method of the present embodiment, an example of manufacturing a propeller shaft to be mounted on an FF-based four-wheel drive vehicle will be described. However, the production method of the present invention is not limited to such elongated members that are elongated in one direction, and can be applied to the production of various three-dimensional structures made of fiber-reinforced resin. Moreover, such a three-dimensional structure is not limited to the field related to automobiles, but is applied to various fields such as aircraft, ships, industrial machinery, and sports/leisure.

<<First Embodiment>>
In the following, after an outline of a propeller shaft as a fiber-reinforced resin structure is described, a method for manufacturing a propeller shaft and a mold device used in this manufacturing method will be described in detail.

<Propeller shaft>
FIG. 1 is an explanatory diagram of the configuration of a propeller shaft 10 (structure made of fiber-reinforced resin). 1 shows the side shape of the propeller shaft 10 on the upper side of the paper with the central axis of the propeller shaft 10 as a boundary, and the cross-sectional shape along the central axis of the propeller shaft 10 on the lower side of the paper. Note that the front-rear direction indicated by an arrow in FIG. 1 corresponds to the front-rear direction of the vehicle on which the propeller shaft 10 is mounted.

As shown in FIG. 1, the propeller shaft 10 includes a substantially cylindrical tubular body 11 (pipe) extending in the longitudinal direction of the vehicle.
As shown in FIG. 1 , the tubular body 11 has a general portion 17 that occupies most of the tubular body 11 in the longitudinal direction of the propeller shaft 10 and extends in the front-rear direction with substantially the same diameter, and a general portion 17 that is disposed rearward of the general portion 17 . A small-diameter portion 18 having a smaller diameter than the portion 17 and extending in the front-rear direction, and a tapered portion 19 arranged to connect the general portion 17 and the small-diameter portion 18 and having a gradually reduced diameter toward the rear are provided.
It is assumed that the tubular body 11 in this embodiment is made of carbon fiber reinforced resin (CFRP), as will be described later. However, the fibers constituting the tubular body 11 are not limited to carbon fibers, and other fibers such as glass fibers, aramid fibers, boron fibers, alumina fibers, silicon carbide fibers, and cellulose fibers can also be used.

The propeller shaft 10 includes a base 12a of a stub yoke 12 forming a cardan joint (not shown) in front of the tube 11, and a collar connecting the base 12a and the front end of the tube 11 (general portion 17). It has a member 13 and a stub shaft 14 of a constant velocity joint (not shown) joined to the rear end of the tubular body 11 (small diameter portion 18).

The base portion 12a of the stub yoke 12 in this embodiment is formed in a columnar shape short in the front-rear direction, and the collar member 13 is formed in a cylindrical shape. The outer diameter of the collar member 13 is formed to be the same as the outer diameter of the base portion 12 a of the stub yoke 12 . The base portion 12a of the stub yoke 12 and the collar member 13 are coaxially connected to each other by laser welding or the like as described later.

Further, the outer diameter of the collar member 13 is formed to be the same as the outer diameter of the body portion 21 (see FIG. 3) of the mandrel 20 (see FIG. 3) which will be described later.
The outer peripheral surface of the rear end portion of the collar member 13 is connected to the inner peripheral surface of the front end portion of the tubular body 11 .
Although not shown, the inner peripheral surface of the collar member 13 may be formed with internal teeth spline-joined to a collar member fitting portion 23 (see FIG. 3) of the mandrel 20 described later.

The stub shaft 14 in this embodiment is formed of a rod-like body with a circular cross section that extends coaxially with the tubular body 11 . Specifically, the stub shaft 14 includes a joint portion 15 that is joined to the inner peripheral surface of the tubular body 11 (small diameter portion 18) and a rear extension portion 16 that has a smaller diameter than the joint portion 15 and extends rearward from the joint portion 15. and A joint portion 15 of the stub shaft 14 is formed with a concave portion 15a formed of a cylindrical space that opens forward. Although not shown, a key groove can be formed on the inner peripheral surface of the concave portion 15a so as to engage with a projecting portion 26 (see FIG. 3) of the mandrel 20, which will be described later.
Incidentally, the outer diameter of the joint portion 15 of the stub shaft 14 is formed to be the same as the outer diameter of the small diameter portion 22 (see FIG. 3) of the mandrel 20 (see FIG. 3) described later.

Such a propeller shaft 10 is connected to a transmission (not shown) mounted on the front portion of the vehicle body via a yoke portion (not shown) of the stub yoke 12 . The propeller shaft 10 is also connected via a stub shaft 14 to a final reduction gear (not shown) mounted on the rear portion of the vehicle body. When power (torque) is transmitted from the transmission to the propeller shaft 10, the propeller shaft 10 rotates around the central axis and transmits the power to the final reduction gear.

<Manufacturing method and mold apparatus for propeller shaft>
FIG. 2 is a process explanatory view of manufacturing the propeller shaft 10 (structure made of fiber-reinforced resin) shown in FIG. 1 by the manufacturing method of the first embodiment.
As shown in FIG. 2, the manufacturing method of the first embodiment includes a FW (Filament Winding) process and an RTM (Resin Transfer Molding) process.

(FW process)
The FW process is a process of manufacturing an intermediate body of the propeller shaft 10 (see FIG. 1).
Specifically, the FW process includes a mandrel preparation process S100, a metal member connection process S101, and a fiber installation process S102, as shown in FIG.

In the mandrel preparation step S100, a mandrel is prepared as a core material when forming tubular body 11 (see FIG. 1) made of carbon fiber reinforced resin (CFRP).
FIG. 3 is a vertical cross-sectional view of the mandrel 20. FIG.
As shown in FIG. 3, the mandrel 20 is formed as a substantially cylindrical body elongated in one direction.

The mandrel 20 in this embodiment has a body portion 21 that occupies most of its longitudinal direction and extends with the same diameter, and a body portion 21 that is disposed on one end side of the body portion 21 in the longitudinal direction and has a diameter smaller than that of the body portion 21 in the longitudinal direction. An extending mandrel small-diameter portion 22 and a mandrel taper portion 24 arranged to connect the trunk portion 21 and the mandrel small-diameter portion 22 and gradually decreasing in diameter with distance from the trunk portion 21 are provided. The mandrel 20 is provided with a protruding portion 26 on the opposite side of the mandrel tapered portion 24 of the small diameter portion 22 and extending with the same diameter as the small diameter portion 22 .

The mandrel 20 is arranged on the other end side of the body portion 21 in the longitudinal direction, has a diameter smaller than that of the body portion 21, and extends in the longitudinal direction so that the collar member 13 (see FIG. 1) is fitted thereon. It comprises a collar member fitting portion 23 and a pressure introducing portion 25 which has substantially the same diameter as the projection portion 26 and protrudes axially outward from the collar member fitting portion 23 .

The mandrel 20 as described above serves as a core material for forming the propeller shaft 10 (see FIG. 1) as described above, and the body portion 21 of the mandrel 20 is the general shape of the tubular body 11 (see FIG. 1). The mandrel tapered portion 24 corresponds to the tapered portion 19 (see FIG. 1) of the tubular body 11 (see FIG. 1), and the mandrel smaller diameter portion 22 corresponds to the tubular body 11 (see FIG. 1). ) corresponds to the small diameter portion 18 (see FIG. 1).
Also, the projecting portion 26 of the mandrel 20 is formed to have an outer diameter that fits into the recess 15a (see FIG. 1) of the stub shaft 14 (see FIG. 1).
The internal space 28 of the mandrel 20 communicates with the inside and the outside through openings formed in the pressure introducing portion 25 and the projecting portion 26 .

The pressure introduction unit 25 supplies fluid to the internal space 28 of the mandrel 20 to expand the mandrel 20 in a mandrel expansion step S202 (see FIG. 2) described later. Further, the pressure introduction part 25 is used when depressurizing the internal space 28 of the mandrel 20 in the mandrel extraction step S204 (see FIG. 2) described later. It should be noted that the mandrel 20 in the first embodiment does not necessarily need to be provided with the projecting portion 26 .

Although not shown, external teeth (not shown) spline-connected to internal teeth (not shown) of the collar member 13 (see FIG. 1) are formed on the outer peripheral surface of the collar member inserting portion 23 . ing. Although not shown, the outer peripheral surface of the projecting portion 26 is provided with external teeth (not shown) spline-connected to the internal teeth (not shown) of the recess 15a (see FIG. 1) of the stub shaft 14. formed. The collar member 13 and the collar member inserting portion 23 do not necessarily have to be provided with the internal teeth and the external teeth for spline joining.

The trunk portion 21 has a plurality of grooves 27 (see FIG. 4) arranged at equal intervals in the circumferential direction on the outer peripheral side.
FIG. 4 is a cross-sectional view taken along line IV-IV of FIG.
As shown in FIG. 4, the grooves 27 formed in the mandrel 20 are formed so that the peripheral surface of the mandrel 20 is partially recessed in a semicircular shape toward the central axis when viewed in cross section of the mandrel 20. . Such a groove 27 extends along the body portion 21 in the axial direction. That is, the depth direction of each groove 27 coincides with the radial direction about the axis of the mandrel 20 when viewed in the axial direction. The peripheral surface of the mandrel 20 having such a plurality of grooves 27 has a bellows shape in the circumferential direction.
It is assumed that the mandrel 20 in this embodiment is made of the above thermoplastic resin.
Such a mandrel 20 is extracted from the inside of the molded tubular body 11 (see FIG. 1) in the mandrel extracting step S204 (see FIG. 2) described later. However, the propeller shaft (not shown) can also be configured with the mandrel 20 left inside the tubular body 11 . The material of the mandrel (not shown) intended to remain inside the tubular body 11 is not particularly limited as long as it has a predetermined rigidity, and various materials such as resin and metal can be used. be able to.

In addition, the material of the mandrel 20 (see FIG. 3) in this embodiment, which is to be extracted from the inside of the molded tubular body 11 (see FIG. 1), is, for example, due to energy such as heat, electricity, vibration, load, etc. It is assumed that it can be deformed, melted, decomposed, destroyed, or eluted with a predetermined eluent or the like. Specifically, the material of the mandrel 20 includes, for example, thermoplastic resins such as ABS resin, polypropylene, and polyethylene terephthalate, SMPs (Shape Memory Polymers) such as silicone-based shape memory polymers, and thin plates made of light metals such as aluminum alloys. Materials and the like can be cited, but are not limited to these as long as the state of the mandrel 20 (see FIG. 3) can be changed so that it can be taken out from the inside of the tubular body 11 (see FIG. 1).

Next, the metal member connection step S101 (see FIG. 2) will be described.
FIG. 5 is a cross-sectional view of a connecting body 41 in which the collar member 13 and the stub shaft 14 are connected to the mandrel 20. As shown in FIG. The collar member 13 and the stub shaft 14 in this embodiment correspond to the "metal member" in the claims.

In this metal member connecting step S101, as shown in FIG.
Specifically, the collar member 13 is splined to the collar member insert 23 of the mandrel 20 as described above. Also, the joint 15 of the stub shaft 14 is splined to the protrusion 26 of the mandrel 20 as described above.

That is, in this connecting body 41, the rotation of the collar member 13 in the circumferential direction of the collar member insertion portion 23 is suppressed, but the displacement of the collar member 13 in the axial direction of the collar member insertion portion 23 is possible. It's becoming Further, in this connecting body 41, rotation of the joint 15 of the stub shaft 14 in the circumferential direction of the projecting portion 26 is suppressed, but displacement of the joint 15 in the axial direction of the projecting portion 26 is allowed. there is

Next, the fiber placement step S102 (see FIG. 2) will be described.
In this fiber installation step S102, the carbon fibers are arranged to correspond to the tubular body 11 shown in FIG. ) on the peripheral surface of the connecting body 41 (see FIG. 5).
That is, at the connecting portion between the collar member 13 (metal member) and the mandrel 20 , the carbon fibers are installed so as to straddle at least part of the collar member 13 (metal member) and the mandrel 20 . Moreover, at the connecting portion between the mandrel 20 and the stub shaft 14 (metal member), the carbon fibers are installed so as to straddle the mandrel 20 and at least part of the stub shaft 14 (metal member).
Specifically, on the peripheral surface of the connecting body 41 (see FIG. 5), the following first fiber layer 30a (see FIG. 6A), second fiber layer 30b (see FIG. 6B) and third fiber layer 30c ( 6C) are formed in this order, the carbon fibers 31 (see FIGS. 6A to 6C). In the first embodiment, dry carbon fibers 31 that are not impregnated with resin are used.

FIG. 6A is a schematic diagram showing how the first fiber layer 30a is formed on the connecting body 41 in the fiber installation step S102 (see FIG. 2). FIG. 6B is a schematic diagram showing how the second fiber layer 30b is formed on the connecting body 41 in the fiber installation step S102 (see FIG. 2). FIG. 6C is a schematic diagram showing how the third fiber layer 30c is formed on the connecting body 41 in the fiber installation step S102 (see FIG. 2).
6A to 6C show only part of the carbon fibers 31 installed on the peripheral surface of the connecting body 41 for convenience of drawing.

As shown in FIG. 6A, the first fiber layer 30a is formed by being placed on the peripheral surface of the connecting body 41 so that the carbon fibers 31 are oriented at 0 degrees (deg) with respect to the axial direction of the connecting body 41. be. In the step of forming the first fiber layer 30a, a plurality of first fiber layers 30a are formed on the peripheral surface of the connecting body 41 moving in the axial direction by carbon fibers pulled out from a bobbin of a braider (not shown). be done.

Next, in this fiber installation step S102 (see FIG. 2), the second fiber layer 30b (see FIG. 6B) is formed on the first fiber layer 30a (see FIG. 6A).
As shown in FIG. 6B, the second fiber layer 30b is formed by being placed on the peripheral surface of the connecting body 41 so that the carbon fibers 31 are oriented at 45 degrees (deg) with respect to the axial direction of the connecting body 41. be done. In the step of forming the second fiber layer 30b, a plurality of bobbins moving in the circumferential direction on the inner peripheral side of an annular braider (not shown) installed around the connecting body 41 and moving in the axial direction of the connecting body 41 A plurality of second fiber layers 30b are provided on the peripheral surface of the connecting body 41 by carbon fibers drawn out from (not shown).

Next, in this fiber installation step S102 (see FIG. 2), the third fiber layer 30c (see FIG. 6C) is formed on the second fiber layer 30b (see FIG. 6B).
As shown in FIG. 6C, the third fiber layer 30c is installed on the peripheral surface of the connecting body 41 so that the carbon fibers 31 are oriented at −45 degrees (deg) with respect to the axial direction of the connecting body 41. It is formed. In the step of forming the third fiber layer 30c, the carbon fibers fed from a plurality of bobbins (not shown) that move in a direction opposite to the step of forming the second fiber layer 30b (see FIG. 6B) rotate the connecting body 41 around the connecting body 41. A plurality of third fiber layers 30c are installed on the surface.

Incidentally, each of the first fibrous layer 30a, the second fibrous layer 30b, and the third fibrous layer 30c has a so-called non-crimp structure in which constituent fibers do not crimp.
In the following description, the first fiber layer 30a, the second fiber layer 30b, and the third fiber layer 30c are not particularly distinguished from each other, and the first fiber layer 30a, the second fiber layer 30b, and the first fiber layer 30a, the second fiber layer 30b, and The layered body of carbon fibers 31 made up of the third fiber layer 30c may be simply referred to as the fiber layer 30 in some cases.

In such a fiber placement step S102 (see FIG. 2), the inside of the mandrel 20 (see FIG. 5) is filled with a fluid such as air through the pressure introduction part 25 (see FIG. 5), and the internal pressure of the mandrel 20 is increased. can also be increased. As a result, when torque (load) is applied to the mandrel 20 in the process of placing the carbon fibers 31 on the mandrel 20, the rigidity of the mandrel 20 is increased due to the increase in internal pressure. This prevents deformation of the mandrel 20 .
Upon completion of the FW process, the intermediate 42 (see FIG. 7) of the propeller shaft 10 (see FIG. 1) to be supplied to the next RTM process is completed.

(RTM process)
The RTM process includes a process of filling a thermosetting resin in the mold 51 (see FIG. 7) of the present embodiment in which the intermediate body 42 (see FIG. 7) is placed and curing the propeller shaft 10 (see FIG. 7). (See FIG. 1).
Specifically, as shown in FIG. 2, the RTM process includes a mold apparatus preparation process S200, an intermediate body installation process S201, a mandrel expansion process S202, a molding process S203, and a mandrel removal process S204. are doing.

In the mold apparatus preparation step S200 (see FIG. 2), a mold 51 (see FIG. 7) having an internal space 53 in which the intermediate 42 (see FIG. 7) is arranged is prepared.
FIG. 7 is an explanatory diagram of the configuration of the mold device 50 prepared in the mold device preparation step S200 (see FIG. 2).
As shown in FIG. 7, the mold device 50 of the present embodiment includes a mold 51 composed of a first split mold 51a and a second split mold 51b, and an opening surface 55, which will be described later, of the mold 51. A sealing member S that seals between the mold 51 and the intermediate 42 at the position where the and have In addition, in FIG. 7, the pressure application unit 60 is indicated by an imaginary line (a two-dot chain line) for convenience of drawing.

The mold 51 of the present embodiment forms an inner space 53 in which the intermediate 42 is arranged when the first split mold 51a and the second split mold 51b are put together. This internal space 53 forms a cavity having the same shape as a preformed body 43 (see FIG. 10), which will be described later.
The mold 51 also has an opening surface 55 through which the internal space 53 of the mold 51 faces the outside. The opening surface 55 is formed on one side in the extending direction of the axis Ax of the internal space 53 of the mold 51 (hereinafter sometimes simply referred to as "axis Ax direction"). And the other side is closed. Specifically, the opening surface 55 is formed at a portion of the internal space 53 of the mold 51 where the portion corresponding to the pressure introduction portion 25 of the intermediate body 42 (mandrel 20) faces the outside.
That is, the intermediate body 42 (mandrel 20) is installed in the internal space 53 of the mold 51 so that the inside of the intermediate body 42 (mandrel 20) and the outside of the mold 51 communicate with each other via the pressure introducing portion 25. . A portion of the pressure introducing portion 25 in this embodiment is exposed to the outside of the mold 51 through the opening surface 55 . However, the pressure introduction part 25 is not limited to one exposed to the outside of the mold 51 through the opening surface 55, as will be described later in detail.

The mold 51 also has a resin supply path 58 and a resin discharge path 57 that communicate with the internal space 53 . The resin discharge path 57 faces the lower end portion of the fiber layer 30 of the intermediate body 42 placed in the mold 51 via the resin reservoir 59 . Also, the resin supply path 58 faces the upper end portion of the fiber layer 30 of the intermediate body 42 via a resin reservoir 59 .
As shown in FIG. 7, the mold apparatus 50 of the present embodiment is assumed to be placed vertically, in which the axis Ax extends along the vertical direction. It is also possible to adopt a so-called horizontal configuration in which the are arranged along the horizontal direction.

The sealing member S is arranged between the intermediate body 42 and the mold 51 in the radial direction of the intermediate body 42, as shown in FIG. Specifically, the sealing member S is arranged between the outer peripheral surface of the pressure introducing portion 25 of the intermediate body 42 (mandrel 20 ) and the inner wall of the mold 51 .
The seal member S in the present embodiment is arranged substantially in the center of the area in the interior space 53 of the mold 51 in which the pressure introducing portion 25 is arranged in the direction of the axis Ax. However, the arrangement position of the sealing member S may be arranged so as to be adjacent to the opening surface 55 in the direction of the axis Ax as described above. It may be in the vicinity of the end.
The sealing between the intermediate body 42 (the pressure introducing portion 25) and the mold 51 by the sealing member S in this embodiment is performed either before or after the expansion of the mandrel 20 in the mandrel expansion step S202 described later. achieved at some point.

Next, the pressure application unit 60 (see FIG. 7) that constitutes the mold device 50 will be described.
In FIG. 7, the pressure application unit 60 indicated by the imaginary line (double-dot chain line) is the pressure introducing portion 25 of the intermediate 42 placed in the mold 51 in the intermediate installation step S201 (see FIG. 2) described later. , and fixed to the mold 51 by a fixture (not shown).

As shown in FIG. 7, the pressure applying unit 60 includes a connecting hole 63 that connects the pressure introducing portions 25 in an airtight and liquid-tight manner, a pressure regulating chamber 61 facing the tip of the connected pressure introducing portion 25, a compressor (not shown), and a and a pressure medium flow path 62 having one end connected to the vacuum suction device and the other end communicating with the pressure regulating chamber 61 .

Following the mold apparatus preparation step S200 (see FIG. 2) for preparing the mold apparatus 50 as described above, the intermediate installation step S201 (see FIG. 2) is performed in the manufacturing method of the present embodiment.
In the intermediate installation step S201, as shown in FIG. 7, the first split mold 51a and the second split mold 51b are horizontally arranged (horizontal direction of the paper surface of FIG. 7) so as to sandwich the intermediate 42 inside. can be matched. As a result, the intermediate body 42 is installed in the internal space 53 of the mold 51 so that the stub shaft 14 is positioned above and the collar member 13 is positioned below.
The pressure introducing portion 25 of the intermediate 42 (mandrel 20) is exposed to the outside of the mold 51 through the opening surface 55 as described above.
Also, the trunk portion 21 of the intermediate 42 placed in the internal space 53 of the mold 51 forms a clearance CL with the inner wall of the mold 51 .
In FIG. 7, reference numeral 52 denotes a seam between the first split mold 51a and the second split mold 51b.

Next, the mandrel expansion step S202 (see FIG. 2) will be described.
FIG. 8A is a schematic diagram showing how the internal space 28 of the mandrel 20 is pressurized in the mandrel expansion step S202 (see FIG. 2). FIG. 8B is a schematic diagram showing the state of the intermediate 42 after undergoing the mandrel expansion step S202 (see FIG. 2).
In this mandrel expansion step S202, a pressurized medium is supplied to the internal space 28 of the mandrel 20 by the pressure application unit 60 shown in FIG.

As a result, the intermediate 42 expands within the internal space 53 of the mold 51 as the mandrel 20 expands, as shown in FIG. 8A.
At this time, the mandrel 20 formed in a bellows shape in the circumferential direction by the plurality of grooves 27 expands in diameter together with the fiber layer 30 .
Then, as shown in FIG. 8B, the preform 42 after undergoing the mandrel expansion step S202 (see FIG. 11) is expanded by expanding the diameter of the expanding mandrel 20 while eliminating the grooves 27 (see FIG. 14A). 30 is brought close to or in close contact with the inner wall of mold 51 .

Next, the molding step S203 (see FIG. 2) of the propeller shaft 10 (structure made of fiber-reinforced resin) by the mold device 50 will be described.
In this molding step S203 (see FIG. 2), first, after the inside of the mold 51 is vacuumed through the resin discharge path 57, as shown in FIG. Supply curable resin. Also, excess thermosetting resin is discharged out of the mold 51 through the resin discharge path 57 . As a result, the thermosetting resin is efficiently impregnated from above to below while eliminating air bubbles in the fiber layer 30 of the expanded intermediate body 42 placed in the mold 51 .
Examples of thermosetting resins include, but are not limited to, epoxy resins, phenol resins, unsaturated polyester resins, and polyimide resins.

Next, in this molding step S203 (see FIG. 2), the mold 51 is heated by a predetermined heat source (not shown). As a result, the thermosetting resin supplied into the mold 51 is cured.
FIG. 9 is a schematic diagram showing how the preformed body 43 is obtained in the mold 51 in the molding step S203 (see FIG. 2).
As shown in FIG. 9, the preform 43 of the propeller shaft 10 (see FIG. 1) includes a mandrel 20, a tubular body 11 made of carbon fiber reinforced resin (CFRP) formed on the outer peripheral surface of the mandrel 20, and a heat exchanger. A collar member 13 (see FIG. 7) integrated with the tubular body 11 by hardening the curable resin, and a stub shaft 14 (see FIG. 7) integrated with the tubular body 11 are provided.
Although not shown in FIG. 2, after the preformed body 43 (see FIG. 9) is removed from the mold 51 (see FIG. 9) by mold opening, it is formed in the resin pool 59 (see FIG. 7). The resin layer (not shown) is removed. Examples of the method for removing the resin layer include cutting methods such as grinder and lathe processing, but are not limited thereto. Note that the removal of this resin layer is not always necessary.

Next, the mandrel extraction step S204 (see FIG. 2) will be described.
FIG. 10 is a cross-sectional view of the preform 43 (see FIG. 9) after the mandrel removing step S204 (see FIG. 2). In addition, in FIG. 10, the mandrel 20 that has been pulled out is indicated by an imaginary line (a two-dot chain line).

As shown in FIG. 10, in the mandrel removing step S204 (see FIG. 2), the mandrel 20 is removed from the end opening 13a side of the collar member 13 to the outside of the tubular body 11 in the direction indicated by the two-dot chain arrow. .
At this time, the mandrel 20 (see FIG. 10) is deformed, melted, decomposed, destroyed, or eluted from the inside of the tubular body 11 according to the methods described above depending on the material used. taken out. As a result, the weight of the propeller shaft 10 (see FIG. 1) can be reduced.

Further, when the mandrel 20 (see FIG. 10) is deformed and taken out from the end opening 13a (see FIG. 9), for example, the internal space 28 of the mandrel 20 is decompressed so that the mandrel is pulled out from the end opening 13a. A method of contracting 20 to a smaller size and extracting it from tubular body 11 (see FIG. 10) can be adopted.
Specifically, for example, the pressure introduction part 25 of the preform 43 (see FIG. 10) taken out from the mold 51 (see FIG. 9) is connected to the pressure applying unit 60 shown in FIG. A vacuum suction device (not shown) connected to the flow path 62 may be used to draw a vacuum.
Such an extracting method can be preferably carried out by plasticizing the mandrel 20 made of thermoplastic resin by heating or the like. Further, such an extraction method can also be suitably applied to a mandrel 20 made of an aluminum thin plate that has undergone bellows-like processing or diamond-cutting, which will be described later, for example.

Then, as shown in FIG. 1, the base 12a of the stub yoke 12 is joined to the collar member 13 by laser welding or the like to complete the propeller shaft 10 of the present embodiment.
In addition, in the manufacturing method of this embodiment, the mandrel extraction step S204 (see FIG. 2) can be omitted. According to such a manufacturing method, the propeller shaft 10 (see FIG. 1) is obtained in which the mandrel 20 (see FIG. 10) is left inside the tubular body 11 (see FIG. 1).

Next, the effects of the first embodiment will be described.
In general, in the RTM molding method in which the fibers of the intermediate are impregnated with a thermosetting resin in a predetermined mold, when placing the intermediate in the mold, The fibers of the position can get caught in this seam.

In contrast, the manufacturing method using the mold apparatus 50 of the present embodiment has a mandrel expansion step S202 for expanding the mandrel 20 before the molding step S203.
According to such a manufacturing method, the clearance CL is formed between the inner wall of the mold 51 and the intermediate 42 in the intermediate installation step S201 for installing the intermediate 42 in the mold 51 . This more reliably prevents the carbon fibers 31 of the intermediate body 42 from getting caught in the seams 52 between the split dies 51 .

Further, in the mold device 50 of the present embodiment, the mold 51 has an opening surface 55 in which one end portion of the internal space 53 in the direction of the axis Ax is opened. When the intermediate body 42 formed by placing the carbon fibers 31 on the mandrel 20 is placed in the mold 51 , the pressure introducing portion 25 of the mandrel 20 is exposed from the opening surface 55 . As a result, there is no need to separately form a flow path for the pressure medium in the thickness direction of the meat portion of the mold 51 .
Therefore, according to this embodiment, the mold 51 that can easily apply pressure to the mandrel 20 can be constructed.

Further, the mold device 50 of this embodiment has a seal member S that seals between the mold 51 and the intermediate body 42 so as to be adjacent to the opening surface 5 .
According to such a mold device 50, in the molding step S203 in which resin is filled into the mold 51 through the resin supply path 58, leakage of resin from the opening surface 55 is more reliably prevented. That is, the mold device 50 is configured to provide both the opening surface 55 in the mold 51 to apply pressure to the inside of the mandrel 20 and to prevent the resin from leaking out from the inside of the mold 51. It has become. According to such a mold device 50, it is possible to maintain excellent quality stability of the obtained propeller shaft 10 (structure made of fiber-reinforced resin).

Further, the fiber-reinforced resin structure obtained by the manufacturing method of the present embodiment is a tubular body made of fiber-reinforced resin, and the intermediate 42 is formed by placing the carbon fibers 31 around the mandrel 20. It is Then, in the mandrel expansion step S<b>202 , the intermediate 42 is expanded inside the mold 51 via the pressure introducing portion 25 of the mandrel 20 .
In this manufacturing method, since the internal space 28 of the mandrel 20 can be directly pressurized, the intermediate 42 can be efficiently expanded within the mold 51 . According to such a manufacturing method, it is possible to efficiently obtain a high-quality fiber-reinforced resin structure that is lightweight and has excellent mechanical strength.

In addition, in the manufacturing method of the present embodiment, the intermediate body 42 connects the collar member 13 and the stub shaft 14 as metal members to the mandrel 20, and at least one of the mandrel 20 and the collar member 13 (metal member). and at least part of the stub shaft 14 (metallic member) are provided with carbon fibers 31 (fibers). That is, in the intermediate body 42 , the carbon fibers 31 are installed so as to straddle the joint portion 15 of the stub shaft 14 from the collar member 13 so as to correspond to the tubular body 11 .
According to such a manufacturing method, the connection strength between the mandrel 20 and the metal members (the collar member 13 and the stub shaft 14) in the intermediate body 42 is further improved.

Moreover, the manufacturing method of the present embodiment further includes a mandrel removing step S204 for removing the mandrel 20 from the propeller shaft 10 (fiber-reinforced resin structure) after the molding step S203.
According to such a manufacturing method, it is possible to reduce the weight of the resulting propeller shaft 10 (structure made of fiber-reinforced resin).

In the manufacturing method of the present embodiment, in the mandrel removing step S204, the internal space 28 of the mandrel 20 is depressurized, and then the mandrel is contracted and removed.
According to such a manufacturing method, the mandrel 20 can be easily removed from the propeller shaft 10 (fiber-reinforced resin structure) without damaging the tubular body 11 or the like arranged adjacent to the mandrel 20 .

The mandrel 20 used in the manufacturing method of this embodiment has grooves 27 formed on its surface.
According to such a manufacturing method, it is possible to increase the amount of expansion compared to the mandrel 20 that does not have the grooves 27 . Accordingly, in the intermediate installation step S201 for installing the intermediate 42 in the mold 51, a larger clearance CL is ensured between the inner wall of the mold 51 and the intermediate 42. As a result, the carbon fibers 31 of the intermediate 42 are more reliably prevented from being caught in the seams 52 between the split dies 51 .

Moreover, in the manufacturing method of this embodiment, the mandrel 20 can be made of resin.
According to such a manufacturing method, the mandrel 20 with excellent dimensional accuracy can be mass-produced at low cost by injection molding or the like, and the dimensional accuracy of the obtained propeller shaft 10 can be improved and the manufacturing cost can be reduced.
In addition, in the manufacturing method of the present embodiment, by forming the mandrel 20 from resin, it becomes easier to remove the mandrel 20 from the tubular body 11 in the mandrel removing step S204.

<<Second embodiment>>
Next, a method for manufacturing the propeller shaft 10 (fiber-reinforced resin structure) according to the second embodiment and a mold device 50 used in this manufacturing method will be described.
FIG. 11 is a process explanatory drawing of the manufacturing method of the second embodiment. FIG. 12 is an enlarged cross-sectional view of the lower part of the mold device 50 used in the manufacturing method of the second embodiment. In addition, in FIG.11 and FIG.12, the same code|symbol is attached|subjected about the component similar to 1st embodiment, and the detailed description is abbreviate|omitted.

As shown in FIG. 11, in the manufacturing method of the second embodiment, the pressing step S300 is performed prior to the mandrel expansion step S202. and the mandrel expansion step S202 are performed in parallel. In other words, the pressing step S300 and the mandrel expansion step S202 may be performed at the same time or slightly shifted from each other. Although not shown, the pressing step S300 can be performed after the mandrel expansion step S202.
In this pressing step S300, the pressing mechanism 70 (see FIG. 12) of the mold device 50 (see FIG. 12) according to the second embodiment presses a part of the intermediate 42 exposed from the opening surface 55 of the mold 51, That is, it is performed by urging the pressure introducing portion 25 toward the inner space 53 side of the mold 51 .

As shown in FIG. 12 , the pressing mechanism 70 is configured with an elastic coil spring 73 arranged in a spring chamber 61 formed in the pressure applying unit 60 .
The spring chamber 61 has a larger diameter than the pressure introducing portion 25 of the mandrel 20 and is formed as a columnar space formed coaxially with the axis Ax. Further, the depth defined in the direction along the axis Ax of the spring chamber 61 is deeper than the length of the pressure introduction portion 25 exposed from the opening surface 55 of the mold 51, and the pressure introduction portion 25 is provided in the spring chamber 61. and a part of the extended portion 25a of the pressure introducing portion 25, which will be described below, are accommodated in the direction of the axis Ax.

On the other hand, the pressure introduction portion 25 of the mandrel 20 applied to the mold device 50 of the second embodiment further has an extension portion 25a extending along the direction of the axis Ax.
The extension portion 25a has a diameter smaller than that of the pressure introduction portion 25, which is the base end portion, and extends with the same diameter in a direction away from the base end portion side.
The extension portion 25a is inserted through an extension portion insertion hole 63 formed in the lower portion of the pressure application unit 60 so as to be coaxial with the axis Ax, and the tip of the extension portion 25a protrudes outside the pressure application unit 60. ing.
The pressure applied to the internal space 28 of the mandrel 20 in the mandrel expansion step S202 is performed through the pressure medium flow path 62 of the extension portion 25a.
Incidentally, when the pressing step S300 is performed after the mandrel expanding step S202 as described above, the pressing mechanism 70 described below is attached to the mold 51 that has undergone the mandrel expanding step S202.

In FIG. 12, reference numeral 73a denotes an upper spring seat of the resilient coil spring 73 formed by a stepped portion between the pressure introduction portion 25 which is the base end portion and the extension portion 25a, and reference numeral 73b denotes the spring chamber 61. It is a lower spring seat of the resilient coil spring 73 formed around the extension insertion hole 63 at the bottom of the .
Incidentally, the urging means for urging the pressure introducing portion 25 toward the inner space 53 of the mold 51 is not limited to the resilient coil spring 73, and various elastic members can be used.

According to the manufacturing method using the mold device 50 having such a pressing mechanism 70, when the intermediate body 42 is expanded by the pressure applying unit 60, the intermediate body 42 is deformed so as to extend in the direction of the axis Ax as well. , the elastic coil spring 73 restrains the extension of the intermediate body 42 by the block body 71 .
As a result, the intermediate 42 can effectively adhere to the inner wall of the mold 51 in the mandrel expansion step S202. In other words, the effective reduction of the clearance CL prevents the mandrel 20 from being filled with more resin than necessary. The resulting propeller shaft 10 (structure made of fiber-reinforced resin) can more reliably achieve weight reduction.

Although the first embodiment and the second embodiment of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.
As shown in FIG. 7, the intermediate 42 of the first embodiment is installed in the internal space 53 of the mold 51 so that the pressure introducing portion 25 is exposed from the opening surface 55 of the mold 51. As shown in FIG. However, it is sufficient that the intermediate 42 is installed in the internal space 53 of the mold 51 so that the inside of the intermediate 42 (mandrel 20 ) and the outside of the mold 51 communicate with each other via the pressure introducing portion 25 . FIG. 13 referred to here is an enlarged cross-sectional view of a lower portion of a mold device 50 showing a modified example of the pressure introducing portion 25. As shown in FIG. In addition, in FIG. 13, the same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 13, the pressure introducing portion 25 according to the modification is not exposed from the opening surface 55 of the mold 51, unlike the pressure introducing portion 25 shown in FIG. Specifically, the tip of the pressure introducing portion 25 is flush with the lower end surface 54 of the mold 51 .
Although not shown, the pressure introducing portion 25 can also take a form in which the tip thereof retreats toward the seal member S side in the direction of the axis Ax.

10 propeller shaft (fiber reinforced resin structure)
11 tube 13 collar member (metal member)
14 stub shaft (metal member)
20 mandrel 25 pressure introduction part 27 groove of mandrel 28 internal space of mandrel 30 fiber layer 30a first fiber layer 30b second fiber layer 30c third fiber layer 31 carbon fiber (fiber)
42 Intermediate 50 Mold device 51 Mold 51a First split mold 51b Second split mold 52 Seam 53 Interior space of mold 55 Opening surface 70 Pressing mechanism S Seal member S100 Mandrel preparation step S101 Metal member connection step S102 Fiber installation step S200 Mold device preparation step S201 Intermediate body installation step S202 Molding step S203 Mandrel expansion step S204 Mandrel withdrawal step

Claims (7)

an opening surface having an opening axially outside the internal space of the mold in which the intermediate body of the fiber-reinforced resin structure composed of the mandrel on which the fibers are placed is arranged;
a seal member arranged between the intermediate body and the mold so as to be adjacent to the opening surface when the intermediate body is arranged in the internal space of the mold;
A mold device comprising: A mold device preparing step for preparing the mold device according to claim 1;
After the mold device preparation step, the intermediate body of the fiber-reinforced resin structure made of the mandrel on which the fibers are installed, and a pressure introduction part for introducing pressure into the intermediate body is provided. an intermediate installation step of installing the obtained intermediate in the internal space of the mold such that the inside of the intermediate and the outside of the mold communicate with each other through the pressure introducing portion;
an expansion step of expanding the intermediate by applying internal pressure from the pressure introducing portion to the intermediate after the intermediate installing step;
a molding step of, after the expansion step, injecting a resin into the mold to mold a fiber-reinforced resin structure;
A method for manufacturing a fiber-reinforced resin structure, comprising: The mold further comprises a pressing mechanism that urges the pressure introduction part from the opening surface side toward the internal space of the mold,
3. The fiber-reinforced resin according to claim 2, further comprising a pressing step of pressing the intermediate against the inner wall of the mold by connecting the pressing mechanism to the pressure introducing portion after the intermediate installing step. method of manufacturing structures. The fiber-reinforced resin structure is a tubular body made of fiber-reinforced resin,
The fiber-reinforced resin according to claim 2 or 3, wherein the intermediate is formed by placing fibers around a tubular mandrel, and the mandrel is provided with the pressure introduction part. method of manufacturing structures. The intermediate includes a mandrel preparation step of preparing the mandrel;
a connecting step of connecting a metal member to the mandrel;
a fiber placement step of placing fibers on the mandrel and at least a portion of the metal member;
The method for manufacturing a fiber-reinforced resin structure according to claim 4, wherein the structure is manufactured by 6. The method for manufacturing a fiber-reinforced resin structure according to claim 5, further comprising a removing step of removing the mandrel from the fiber-reinforced resin structure after the molding step. 7. The method of manufacturing a fiber-reinforced resin structure according to claim 6, wherein in the extracting step, the mandrel is contracted and removed after reducing the pressure in the inner space of the mandrel.

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