JP3031110B2 - Method and apparatus for producing preform for fiber reinforced composite material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for producing a preform for a fiber-reinforced composite material. More specifically, the present invention relates to a method and an apparatus for manufacturing a preform for a fiber-reinforced composite material by suturing a laminated base material such as a carbon fiber fabric with a sewing thread such as carbon fiber or glass fiber.

[0002]

2. Description of the Related Art Carbon fiber fabrics are widely used in various fields as base materials for composite materials because of their excellent handleability. The fiber-reinforced fabric is rarely formed by one piece into a fiber-reinforced plastic (hereinafter referred to as FRP), and is mostly formed by laminating many pieces such as cross-lamination. However, in such a laminated textile substrate, when a slight external force acts, the lamination is displaced, so it must be handled very carefully, which is very troublesome. Is difficult to obtain. In addition, there is also a problem that the strength between layers is low because the sheet-like materials are laminated.

[0003] Such a problem is described in Japanese Patent Publication No. 64-114.
It is improved by stitching a sheet-like substrate with a sewing thread made of reinforcing fibers as proposed in Japanese Patent No. 55-55.

[0004] However, as a method of sewing a large number of laminated base materials with sewing threads, there is a method of performing single-ring sewing or lockstitching with a sewing machine. However, sewing can be performed only in a single line, and breakage such as carbon fiber breakage. When a brittle fiber having low elongation is used as a sewing thread, there is a problem that the fiber is easily broken. In addition, since the feeding mechanism of the base material is configured to feed the material by scratching with a sharp nail, there is also a problem that the reinforcing fibers on the base material side for the fiber-reinforced composite material are damaged.

[0005] As another means, there is known a method of simultaneously sewing a laminated base material with a large number of knitting yarns by a technique of sewing a base material by a warp knitting mechanism, and this method exhibits high productivity. However, since the winding is performed at a constant winding speed, the winding tension after forming the loop of the knitting yarn reaches the already formed loop, which tightens the substrate and disturbs the fiber orientation of the substrate. Or the knitting yarn has low elongation at break like carbon fiber,
In the case of brittle fibers, there is a problem that the fibers are easily broken.

[0006] As described above, there is no satisfactory technique for suturing a laminated base material for FRP, and particularly a satisfactory technique for suturing a laminated base material of carbon fiber reinforced plastic (hereinafter referred to as CFRP) as a conventional technique.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and is also applicable to a case where a laminated base material is stitched with a sewing thread of a low elongation and very brittle fiber such as a carbon fiber yarn or a glass fiber yarn. An object of the present invention is to provide a method for producing a preform for a fiber-reinforced composite material by stitching without cutting and without fastening to a substrate, and an apparatus therefor.

[0008]

According to the present invention, there is provided a method of manufacturing a preform for a fiber-reinforced composite material, which stitches a laminated base material while sequentially forming stitches with needles reciprocating at a constant width of movement. In the method of manufacturing a preform for a fiber reinforced composite material, the amount of sewing thread drawn in is determined.
With a spacer of predetermined thickness in the direction of needle movement.
With the position of the laminated substrate
When penetrating the material and hooking the sewing thread on the hook of the needle, the supply of the sewing thread is stopped and simultaneously the tension is applied to the sewing thread, and then the sewing thread is pulled from one side of the laminated base material to the other side by a predetermined stitch length. At the same time, when the sewing thread is pulled in, the supply is stopped and the tension is released to release a low tension state, and then the needle is moved in the direction of the laminated base material and the needle is stacked until the tip of the needle reaches the laminated base material. The method is characterized in that the base material is moved and stitches are formed while sequentially forming stitches.

[0009]

[0010] Further, the apparatus for manufacturing a preform for a fiber-reinforced composite material according to the present invention includes a needle for reciprocating at a constant movement width to stitch a laminated base material and a needle for guiding a sewing thread into a hook of the needle. In the apparatus for manufacturing a preform for a fiber-reinforced composite material, which is arranged with the guides facing each other, a brake mechanism for stopping the supply of the sewing thread when the sewing thread is hooked on the hook of the needle, and a sewing thread for hooking the sewing thread on the hook of the needle. Tensioning mechanism that applies tension to the needle and releases the tension when the sewing thread is pulled in by the needle, and the position of the laminated base material in the direction of needle movement.
The reciprocating motion with the constant movement width
The relative position between the moving end of the
A spacer that determines the stitch length of the stitch formed by the needle, and a mechanism that intermittently moves the laminated base material until the needle moves back and reaches the laminated base material after the needle draws in the maximum amount of sewing thread. Is provided.

In this device, for example, a brake mechanism for sandwiching a sewing thread in a thread path of the sewing thread and stopping the supply thereof, a tension applying mechanism for applying a tension to the sewing thread between the brake mechanism and a stitch portion, A buffer mechanism is provided to alleviate the impact during the application of the tension. The brake mechanism and the tension applying mechanism are activated when the sewing thread is supplied to the hook of the needle, and released when the needle is retracted.

The substrate in the present invention is not particularly limited, and includes a substrate having carbon fiber, glass fiber, polyaramid fiber (Kevlar) or the like as a reinforcing fiber. Is suitable for a warp and a weft or a laminate of a woven fabric substrate having a warp or a weft. As a method of laminating the substrates, the carbon fibers may be laminated so as to be in the same direction, or may be laminated while being shifted by 45 °. Further, it may be laminated together with another base material such as a mat. Further, the sewing thread is not particularly limited, but includes carbon fiber, glass fiber, and polyaramid fiber.The present invention is particularly applicable to a double thread sewing thread in which a carbon fiber thread or a carbon fiber thread has a lower twist and an upper twist. The effect appears more remarkably.

[0013]

In the method and the apparatus according to the present invention, the movement of the laminated base material is stopped, the sewing thread is drawn in by a predetermined stitch length (loop length) by the needle, and then the needle reaches the laminated base material until the needle reaches the laminated base material. Since the laminated base material is intermittently fed, it is possible to apply tension to the sewing thread only when the sewing thread is guided to the hook of the needle, and to make the tension state substantially zero when forming the loop. Even if small and brittle fibers are used as sewing thread, the fibers will not be damaged or cut, and the laminated base material can be stitched with high-strength reinforcing fibers such as carbon fiber, and high interlayer reinforcement can be easily achieved. it can. At the same time, by releasing the tension,
Since there is no tightening of the sewing thread to the base material, FRP that exhibits a high reinforcing effect without disturbing the fiber orientation of the base material,
In particular, CFRP is obtained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings for a laminated substrate in which the reinforcing fibers are carbon fibers (hereinafter abbreviated as a carbon fiber laminated substrate). FIG. 1 shows a stitching apparatus for a carbon fiber laminated base material according to an embodiment of the present invention, and 1 shows a carbon fiber laminated base material. Are supplied from the front and superimposed.

Reference numeral 3 denotes a needle, and a needle bed 9
And is moved up and down with a constant movement width by a cam mechanism (not shown). Reference numeral 4 denotes a guide, which guides the sewing thread 2 into the hook 3a of the needle 3 by performing a swing motion and a lapping motion in the same manner as the guide motion of the warp knitting machine when the needle 3 goes up through the base material 1. .

A large number of sewing threads 2 are mounted on a creel (not shown), and are passed through a nip roller 7 as a brake mechanism, a tension bar 6 as a tension applying mechanism, and a spring guide 8 as a buffering mechanism, and are inserted into holes of the guide 4. It is passed through each book.

Reference numeral 5 denotes a take-up roller for nipping the stitched laminated base material 1 with two rollers and taking up the laminated base material 1 while rotating intermittently. Reference numeral 10 denotes a spacer disposed on the lower surface side of the laminated base material 1.

[0018] Figure 2 shows the relationship between the movement of the movement and take-off of Ri roller 5 needle 3, the laminated base material 1 passes over surfaces of the spacer 10, the bottom surface of the spacer 10 is substantially needle tip of It is the lowest position. Fig. 2 (a)
Indicates a state in which the needle 3 has reached the lowest position, and the amount of the thread 2 pulled from the bottom surface of the laminated base material 1 is:
The thickness of the spacer 10 is selected so as to be equal to a predetermined stitch length, that is, equal to the length of the loop. That is,
As described above, the needle 3 is connected to the cam mechanism through the needle bed 9.
The needle moves up and down with a certain width
The lowest position at the end is always a fixed position. And the space
Passes through the upper surface of the spacer 10 according to the thickness of the spacer 10
Of the bottom surface of the laminated base material 1
The relative position of the needle 3 is determined.
Of the sewing thread 2 from the bottom surface of the laminated base material 1
The amount is determined for a predetermined stitch length.

As shown in FIG. 2B, the needle 3 starts to rise and is taken up until the tip of the needle 3 reaches the laminated base material 1 as shown in FIG. By rotating the roller 5, the laminated base material 1 is moved by an amount equal to the loop length.

By operating as described above, the sewing thread 2
When pulling in, the laminated base material 1 is stopped, and the sewing thread 2 can be pulled straight, so that the resistance applied to the sewing thread 2 can be minimized. Therefore, even if the sewing thread is made of a very brittle fiber, it does not break, and even when the laminated base material 1 is taken off, the sewing thread 2 is hardly tensioned. The sewing thread 2 is not cut.

These series of operations are intermittently repeated sequentially, stitched while forming a sequential loop, and the stitched laminated substrate 1 is intermittently fed by the take-up roller 5.

Next, a mechanism for applying a tension to a sewing thread will be described with reference to FIG. Put the sewing thread 2 on the hook 3 of the needle 3
When hooking the needle 2, the needle 3 must be guided to a slight gap between the stem of the needle 3 and the beard. On the other hand, it is preferable that the tension is low in order to pull the sewing thread 2 made of a brittle fiber such as a carbon fiber into the laminated base material 1 without breaking, or for forming a loop.

FIG. 3A shows an embodiment of a method of applying tension when the sewing thread 2 is hooked on the hook 3a of the needle 3. First, the nip roller 7 is closed, and a brake is applied to the sewing thread 2. When the supply is stopped and then the tension bar 6 is raised, tension is applied up to the laminated substrate 1. Since the spring guide 8 is provided between the tension bar 6 and the guide 4, the impact force at the time of applying the tension is reduced, and the sewing thread is not damaged by the application of the tension.

In this state, the sewing thread 2 is guided into the hook 3a of the needle 3. Then, as shown in FIG. 3 (b), when the sewing thread 2 is guided into the hook 3a of the needle 3 and then the needle 3 descends to draw the sewing thread 2,
By lowering the tension bar 6 at the same time releasing the nip roller 7, since it is the this draw suture 2 substantially without tension, sewing thread 2 hook 3 of the needle 3
No damage occurs as a result of being wrung with a.

[0025]

According to the method of the present invention, the laminated substrate is intermittently moved until the needle moves back and the needle tip reaches the bottom of the laminated substrate after the sewing thread is pulled in for a predetermined loop length when the laminated substrate is stopped. In this method, tension is applied to the sewing thread only when the sewing thread is guided to the needle hook, and no tension is applied when the loop is formed. Alternatively, without cutting, for example, the carbon fiber woven laminated substrate can be stitched with a high-strength reinforcing fiber such as carbon fiber, and high interlayer reinforcement can be easily achieved. At the same time, since there is no tightening of the sewing thread to the base material, a high reinforcing effect can be exhibited without disturbing the fiber orientation of the base material.

[Brief description of the drawings]

FIG. 1 is a perspective view of an apparatus for manufacturing a preform for a fiber-reinforced composite material according to an embodiment of the present invention.

FIG. 2 shows a state in which the needle is retracted in the apparatus shown in FIG.
(A)) and an enlarged partial longitudinal sectional view showing a state when the needle is raised (FIG. 2 (B)).

FIG. 3 shows a state before a sewing thread is hooked in the apparatus shown in FIG.
FIG. 4B is a schematic partial configuration diagram illustrating a state after the sewing thread is hooked (FIG. 3B).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carbon fiber laminated base material 2 Sewing thread 3 Needle 3a Needle hook 4 Guide 5 Take-up roller 6 Tension bar 7 Nip roller 8 Spring guide 9 Needle bed 10 Spacer

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP11-11455 (JP, B2) JP53-42979 (JP, B2) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 D05B 1/00-1/26

Claims (3)

(57) [Claims] 1. A method for producing a constant sutured for a fiber-reinforced composite material preforms laminated substrate while forming a sequential stitches by reciprocation to the needle by movement width, stitch
A spacer with a predetermined thickness that determines the amount of thread drawn in
The position of the laminated substrate in the direction of the
When the needle penetrates the laminated base material in a state and hooks the suture on the hook of the needle, the supply of the suture is stopped, and simultaneously the tension is applied to the suture, and then a predetermined amount is applied from one side of the laminated base material to the other side. When the sewing thread is pulled in by the length of the stitch, and when the sewing thread is pulled in, the supply is stopped and the tension is released to release a low tension state, and then the needle is moved in the direction of the laminated base material, and the tip of the needle reaches the laminated base material. A method for producing a preform for a fiber-reinforced composite material, wherein a stitch is formed while moving a laminated base material to form a stitch in sequence until the preform is formed. 2. A preform for a fiber-reinforced composite material comprising a needle for reciprocating at a constant movement width for stitching a laminated substrate and a guide for guiding a sewing thread into a hook of the needle facing each other. In the manufacturing apparatus of the above, a brake mechanism for stopping the supply of the sewing thread when the sewing thread is hooked on the hook of the needle, a tension is applied to the sewing thread when the sewing thread is hooked on the hook of the needle, and the tension is applied when the sewing thread is pulled by the needle. A tension applying mechanism to be released,
Determine the position of the laminated substrate in the direction of needle movement.
And the movement of the needle reciprocating with the constant movement width
A spacer that determines the relative positional relationship between the end and the laminated base material, thereby determining the stitch length of the stitch formed by the needle, and the needle moves back after the needle draws in the maximum amount of sewing thread and is laminated. An apparatus for manufacturing a preform for a fiber-reinforced composite material, further comprising: a mechanism for intermittently moving the laminated base material before reaching the base material. 3. A brake mechanism for sandwiching a sewing thread in a thread path of the sewing thread and stopping the supply of the sewing thread, a tension applying mechanism for applying a tension to the sewing thread between the brake mechanism and a stitch portion, and an impact at the time of applying the tension. The apparatus for producing a preform for a fiber-reinforced composite material according to claim 2, further comprising a buffer mechanism for reducing the pressure.