JP2019156128A - Impact absorption body - Google Patents

Abstract

To provide an impact absorption body which is excellent in absorption characteristics of energy and is lightweight.SOLUTION: An impact absorption body is an impact absorption body having a hollow cylindrical body portion formed of a continuous reinforcement fiber resin composite material containing a fiber bundle containing a continuous reinforcement fiber and a resin, and has an end whose angle α formed by an axial direction of the cylindrical body portion and a direction along an outer surface of the cylindrical body portion is 0.1-30° on one end in the axial direction of the cylindrical body portion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a shock absorber.

2. Description of the Related Art Conventionally, in vehicles such as automobiles, an impact absorber that absorbs an impact applied to the vehicle from the outside at the time of a collision is generally mounted. For example, in a passenger car, shock absorption is performed inside a bumper at the front or rear of the vehicle. A member is used. The shock absorber is formed in a cylinder, for example, and absorbs the shock by being compressed and broken in the axial direction upon receiving the shock. Conventionally, a metal shock absorber made of a metal material (for example, aluminum or iron) has been used as such a shock absorber. However, in recent years, it is desired to reduce the weight of the vehicle, and a fiber reinforced resin. The impact absorbing member made of a lighter material such as the above has been studied.
As an impact absorbing member using such a fiber reinforced resin, for example, Patent Document 1 includes a laminated fiber group including a compression direction fiber layer arranged so that a fiber bundle has a compression direction component, and a compression direction. An energy absorber in which the arrangement density of fiber bundles is changed from one side to the other is disclosed.

JP 2005-193755 A

  However, since the energy absorber described in Patent Document 1 has a fiber bundle arrangement in a direction perpendicular to compression, the energy absorption at the time of collision is mainly energy absorption in which the laminated fiber group delaminates, The present inventors have found that there is a problem that energy absorption due to tensile properties cannot be effectively exhibited. And in the energy absorber of patent document 1, in order to raise the absorbed amount of energy, it is necessary to increase the material which adheres a compression direction fiber layer, and it discovered that the effect of weight reduction was not fully acquired. It was.

  Accordingly, an object of the present invention is to provide a lightweight impact absorber excellent in impact absorbability.

  That is, the present invention is as follows.

[1]
A shock absorber having a hollow cylindrical body portion made of a continuous reinforcing fiber resin composite material containing a fiber bundle containing continuous reinforcing fibers and a resin,
One end of the cylindrical body portion in the axial direction is an end where an angle α between the axial direction of the cylindrical body portion and a direction along the outer surface of the cylindrical body portion is 0.1 to 30 °. A shock absorber characterized by having an end.

[2]
[1] The shock absorber according to [1], wherein the shape of the end portion of the cylindrical body portion is an n truncated pyramid (n is an integer of 3 or more) or a truncated cone.

[3]
The shock absorber according to [1] or [2], wherein the angle α is 0.1 to 30 ° from the one end in the axial direction to the other end in the axial direction.

[4]
The shock absorber according to any one of [1] to [3], wherein at least one of the fiber directions of the fiber bundle forms an angle greater than 0 ° and less than 90 ° with respect to the axial direction.

[5]
The impact absorber according to any one of [1] to [4], wherein the fiber bundle is oriented so that fiber bundles having different fiber directions are constrained by weaving, knitting, or braiding.

[6]
The shock absorber according to any one of [1] to [5], wherein at least a part of the plurality of continuous reinforcing fiber resin composite materials are laminated.

[7]
The shock absorber according to any one of [1] to [6], wherein the reinforcing fiber contained in the continuous reinforcing fiber is a fiber having no yield point.

  ADVANTAGE OF THE INVENTION According to this invention, the lightweight impact absorber which is excellent in impact absorptivity can be provided.

(A) (b) is the schematic (perspective view) which shows an example of the impact-absorbing body of this embodiment. It is the schematic (perspective view) which shows the cylindrical body part of FIG.1 (b). (A) is XX sectional drawing of FIG. (B), (c), and (d) are examples of a cross section of a cylindrical body portion of the shock absorber of another embodiment. FIG. 3A is an enlarged view of an example of one end 22 in the axial direction of FIG. 3A, and FIG. 3B is an enlarged view of an example of the one end 22 in the axial direction of FIG. It is an example of the side view which looked at the shock absorber of this embodiment from the direction perpendicular | vertical with respect to an axial direction. It is the schematic of the shock absorber of a comparative example. 1 is a schematic diagram of a mold used in Example 1. FIG.

  Hereinafter, an embodiment of the present invention (hereinafter, also referred to as “this embodiment”) will be described in detail, but the present invention is not limited to this embodiment.

<Shock absorber>
The shock absorber according to the present embodiment is a shock absorber having a hollow cylindrical body portion made of a continuous reinforcing fiber resin composite material including a fiber bundle including continuous reinforcing fibers and a resin. One end of the cylindrical body portion in the axial direction has an end portion where an angle α between the axial direction and a direction along the outer surface of the cylindrical body portion is 0.1 to 30 °.
The shock absorber 1 of the present embodiment may consist of only the cylindrical body portion 2 or may further include other portions such as the flat plate 3.
By having an end with an angle α of 0.1 to 30 °, the end starts to deform so that the cylindrical body part is taken into the hollow inner surface or opened outward at the initial stage of compression fracture. Even if compressive fracture progresses to the other end side in the axial direction, deformation that folds inward or deformation that opens outwardly can be continuously induced, and it does not bend in the middle. In addition, since the continuous reinforcing fiber is deformed so as to be folded inward or opened outward while breaking the continuous reinforcing fiber, the impact energy is absorbed mainly by the breaking of the continuous reinforcing fiber. Therefore, the impact energy can be stably and efficiently absorbed from the tip to the base of the shock absorber.

In this specification, the “axial direction” is a direction from one end 22 of the cylindrical body portion 2 to the other end 23, and the cylindrical body when the shock absorber receives a compressive load at one end. It is good also as a direction where a portion is compressed. The “angle α” is the smaller angle formed by the axial direction AD and the direction along the outer surface 24 of the cylindrical body portion in the cross section cut along the axis 26 of the cylindrical body portion 2 (FIG. 3). An angle in the range of 0 to 90 °. The direction along the outer surface may be the direction of the outer surface 24 passing through a point on the outer surface in the cross section (FIG. 3) (FIG. 3). Further, when the outer surface of the cylindrical body portion is a curved surface, the direction along the outer surface may be a tangential direction of a point on the outer surface. Here, the angle α shown in FIG. 3A is the angle α between the tip 22 and the end 21.
In the present specification, one end 22 in the axial direction of the cylindrical body portion may be referred to as a “tip”, and the other end 23 of the cylindrical body portion may be referred to as a “base end”.

The angle α is more preferably 1 ° to 15 ° from the viewpoint that the area of the impacted surface changes when the deformation progresses in the direction of the base end, so that energy can be more easily absorbed so as to suppress the change in the area. It is. When the angle α is within the upper limit, problems such as unstable energy input and buckling are unlikely to occur, and the energy absorption efficiency is excellent.
The angle α may be an angle formed by a straight line that is close to the shaft 26 at the tip 22 and further away from the shaft 26 toward the base end side and the axial direction AD (FIGS. 3A to 3C). The angle formed by a straight line that is farther from the shaft 26 at the tip 22 and closer to the shaft 26 toward the base end side and the axial direction AD (FIG. 3D). Especially, it is preferable that it is the angle which the straight line and axial direction which leave | separate from an axis | shaft make the base end side.

The end 21 is provided on at least a part including one end 22 in the axial direction of the cylindrical body portion.
In the cross section cut along the axis, the cross section (FIGS. 3A, 3C, and 3D) in which the angles α of the two opposing one ends 22 are both 0.1 to 30 ° and / or one There is preferably a cross section (FIG. 3B) in which the angle α of the one end 22 is 0.1 to 30 °. Especially, it is preferable that the said edge part 21 is provided in the whole said one end 22.
The angle β formed by the axial direction AD of the cylindrical body portion and the direction along the inner surface 25 of the cylindrical body portion is preferably the same as the angle α.

In the end portion 21, the angle α may satisfy the above range as a whole from one end 22 in the axial direction to the other end 23 in the axial direction (FIG. 3 (c)). The angle α may satisfy the above range (FIGS. 3A, 3B, and 3D). The angle α may be the same from one end 22 in the axial direction to the other end side 23 (FIG. 3C) or may be different (FIGS. 3A and 3D).
In addition, there is no point where the angle α changes greatly from one end 22 in the axial direction to the other end side 23 from the viewpoint that it is difficult to buckle during impact absorption and energy absorption due to tensile stress of the fiber is likely to occur. preferable.
Here, when the shock absorber of the present embodiment is used for a vehicle body, from the viewpoint of ease of joining with the vehicle body, the axial direction is crushed when a mounted vehicle body part (for example, a vehicle body frame) receives an impact. The direction is preferably the same as the direction.

From the viewpoint that the cylindrical body portion 2 can have a moderate size shock absorber, is not easily buckled at the time of shock absorption, and is likely to absorb energy mainly based on the tensile stress of the fiber. It is preferable that there is no portion exceeding 30 °.
Further, the shortest distance D (FIG. 3A) between the shaft 26 and the inner surface 25 may be longer or shorter from one end side toward the other end side. Further, there may be a portion having the same shortest distance D.

  In the cross section cut along the axis (FIG. 3), the two opposing end portions 21 have the same or longer shape as the shortest distance D goes from the tip side to the base end side, or the shortest distance D from the tip side. The shape is preferably the same or shorter as it goes toward the base end side.

At the tip 22 of the cross section cut along the axis (FIG. 3), a surface surrounded by the straight line connecting the outer surface side end 22a and the inner surface side end 22b of the cylindrical body portion and the outer surface side end 22a (for example, The angle δ (FIG. 4) in the range of 0 to 90 ° is 0 to 45 from the viewpoint of more easily absorbing energy at the time of impact. It is preferable that it is (degree), More preferably, it is 2-20 degrees, More preferably, it is 1-15 degrees.
4A is an enlarged view of an example of the tip 22 of FIG. 3A, and FIG. 4B is an enlarged view of an example of the tip 22 of FIG. 3D.

The shape of the end portion 21 is preferably an n-pyramidal frustum (n is an integer of 3 or more) (FIG. 3A) or a truncated cone.
Further, the shape of the cylindrical body portion may be a shape that matches the shape of the portion to which the cylindrical body portion is attached. A shape combining a prism (FIG. 3A), a shape combining a truncated cone and a cylinder, a truncated cone and an m prism (m is an integer greater than or equal to 3. n and m may be the same. And may be different), and a combination of an n-pyramidal frustum and a cylinder is preferable. In the above shape, n and m are preferably equal from the viewpoint of excellent shock absorption. For example, when the frame pipe of an automobile is a prism, a shape in which an n-pyramidal frustum and a prism are combined or a shape in which a frustum and a prism are combined can be used.
In addition, when the angle α of the end portion is a hollow n-prism or columnar shape less than 0.1 °, the outer wall of the end portion of the cylindrical body portion is taken into the hollow interior at the initial stage of compression fracture. It may be bent in the middle and folded inward or outward without being deformed or deformed to open outward. In addition, energy absorption due to the tensile stress of the fiber may be difficult to occur. Therefore, it is not preferable because efficient energy absorption cannot be performed.

One end 22 and / or the other end 23 may be closed from the viewpoint that the cylindrical body portion has high rigidity and easily absorbs energy without buckling during impact absorption. Here, closing the end means joining at least a part of the surface surrounded by the end by joining a cover covering the entire surface surrounded by the end, a lattice-shaped cover, a bar or the like.
In addition, the cylindrical body portion has high rigidity, and from the viewpoint of easily absorbing energy without buckling when absorbing the impact, the cylindrical body portion is provided between the one end 22 and the other end 23. A cover, a lattice-shaped cover, a bar, etc. covering the entire surface are joined to at least a part of a surface surrounded by points on the inner surface (preferably, a surface parallel to the impact surface, a surface parallel to the horizontal surface). Also good.
In addition, the cylindrical body portion has a high rigidity, and it is easy to absorb energy without buckling at the time of impact absorption, so that a rib may be provided between one end 22 and the other end 23. Good.
The lid and bar may be the same material as the cylindrical body part, or may be other materials such as metal, resin, wood, and the like.
The cylindrical body part preferably has a hollow hole extending from one end 22 to the other end 23.

  Although the said cylindrical body part may be formed combining several members, it is preferable that the fiber is continuing in the axial direction from a viewpoint of energy absorptivity. Moreover, it is preferable that the fibers are continuous in the circumferential direction of the shaft. For example, it is preferable that the fiber is continuous in the circumferential direction of the shaft in a portion (FIG. 3D) in which the shortest distance D is shortened from the tip side toward the base end side. When the fibers are not continuous in the circumferential direction of the shaft, it is preferable that the shortest distance D becomes longer from the distal end side toward the base end side.

<Structure of shock absorber>
The shock absorber of this embodiment preferably has a cylindrical body portion having a columnar shape or a frustum shape having an axis 26 along the predicted direction of impact. In addition, although it is not the impact absorber of this invention, as another impact absorber which consists of a below-mentioned continuous reinforcement fiber resin composite material, for example, in FIG. 6 (a), it is flat with the crease | fold along the direction of the estimated impact. An example of a shock absorber having a bent shape is shown. FIG. 6B shows an example of a cylindrical cylindrical shock absorber having an axis along the predicted direction of shock.
Fig.1 (a) is a figure which shows an example of the shock absorber of this embodiment. FIG. 1 (a) shows that two hexagonal frustum-shaped cylinders having axes along the predicted direction of impact are joined via a trapezoidal plane on one side of each, and each hexagonal frustum An example of a shock absorber having a structure in which a parallelogram-shaped plane is coupled to the side opposite to the above-mentioned side of the cylindrical body at its long side is shown. As shown in FIGS. 1 and 6, the ridgeline may have a shape such as a linear shape, a zigzag shape, or a wave shape. Moreover, you may have a rib inside a cylindrical body part.
The flat plate 3 that connects the cylindrical body portions may be the same material as the cylindrical body portion, or may be other materials such as metal, resin, wood, and the like. In addition, the number of flat plates connecting adjacent cylindrical body portions may be one (FIG. 1 (b)) or a plurality (FIG. 1 (a)). Moreover, one cylindrical body part may be connected to a plurality of cylindrical body parts through a flat plate.
In addition, the said flat plate is good also for the purpose of maintaining arrangement | positioning of the said cylindrical body part in the shock absorber of this embodiment. In this case, the flat plate is not limited to a plate shape. Moreover, the fiber bundle contained in the cylindrical body portion and the fiber bundle contained in the flat plate need not be continuously connected.

The thickness of the cylindrical body portion may be the same or different as a whole. When the angle δ is greater than 0 °, the thickness of the cylindrical body may be a thickness of a portion excluding a region between the outer surface side end 22a and the inner surface side end 22b.
The impact absorber of the present embodiment preferably has a structure in which a plurality of continuous reinforcing fiber resin composites are laminated at least in part from the viewpoint of adjusting the impact absorption balance. For example, in the case of an impact absorber that is installed inside a bumper in front of a vehicle of a passenger car, in order to reduce the impact on both the impact object outside the vehicle and the object inside the vehicle with respect to the impact from the front of the vehicle due to the impact object, It is desired that the impact object side of the shock absorber is easily collapsed and the object side inside the vehicle is difficult to collapse. That is, in the shock absorber, the part in front of the vehicle that receives the shock at the beginning collapses even with weak impact energy, but from the front to the rear of the vehicle so that a strong impact energy is gradually required for the collapse toward the rear part of the vehicle. An impact absorber having a structure in which the thickness is increased stepwise is desired. Such adjustment of the thickness of the shock absorber can be performed by partially changing the number of laminated continuous reinforcing fiber resin composites. Examples of the method for laminating the continuous reinforcing fiber resin composite include thermal welding and vibration welding.

<Orientation of fiber bundle in shock absorber>
The fiber direction of the fiber bundle of the cylindrical body part (especially, the fiber bundle restrained by weaving, knitting, or assembling from the viewpoint that the area changes with compression and the energy is easily absorbed by the tensile stress in the reinforcing fiber direction. At least one direction of the fiber direction) is preferably more than 0 ° and less than 90 ° with respect to the axial direction, more preferably 30 ° or more and less than 90 °, still more preferably 35 ° or more and less than 80 °, particularly Preferably, it is 40 ° or more and less than 60 °. In particular, it is preferable that at least one of the fiber bundles restrained by weaving, knitting, or braiding is in the above range. Especially, it is more preferable that the fiber direction of all the fiber bundles which comprise a cylindrical body part satisfy | fills the said range.
When 0 ° or 90 ° is not included in at least one direction of the fiber direction of the fiber bundle, delamination becomes difficult and energy absorption due to fiber tensile stress is likely to occur. In particular, by including a fiber direction in which the angle γ is 45 ° or more, delamination is further suppressed, and energy absorption due to fiber tensile stress is more likely to occur.
Here, an angle formed by at least one of the fiber directions of the fiber bundle with respect to the axial direction is an axial direction in a side view of the cylindrical body portion 2 viewed from a direction perpendicular to the axial direction AD. A small angle γ formed by AD and at least one direction of the fiber bundle, which is an angle in the range of 0 to 90 ° (FIG. 5). FIG. 5 is a side view of the cylindrical body portion of FIG. 1A viewed from a direction perpendicular to the axial direction, and is an example in which the direction of two woven fiber bundles exists.
Also, at least one of the fiber directions of the fiber bundle of the cylindrical body portion (particularly the fiber direction of the fiber bundle constrained by weaving, knitting, or pairing) and the axial direction of the cylindrical body portion of the shock absorber These directions may be parallel, and may be perpendicular or other angles. The angle in the case of forming a vertical or other angle may be 45 to 90 °, 60 to 90 °, or 80 to 90 °.

<Shock absorption energy of shock absorber>
The impact absorption energy (height: 120 mm) of the impact absorber of this embodiment is preferably 4.0 to 10 kJ, more preferably 6.0 to 10 kJ, and even more preferably 8.0 to 10 kJ. is there. When the energy of the shock absorber is 8.0 to 10 kJ, it can be used as a general automobile shock absorber, but even a shock absorber with low absorbed energy can be integrated by being dispersed. Necessary absorption energy. Having high energy absorption means that impacts can be absorbed with a small number, and therefore with low cost and low weight.
In the present disclosure, the shock absorption energy of the shock absorber can be measured by the method described in Examples described later.

<Impregnation rate of resin in shock absorber>
In the impact absorber of the present embodiment, the resin impregnation rate with respect to the fiber bundle is preferably 94% or more. When the impregnation ratio of the resin is 94% or more, an impact absorber having a high tensile strength can be obtained. When the shock absorber has a flat plate portion, the resin impregnation rate in the flat plate portion is preferably 94 to 100% in the thickness direction from the flat plate surface, more preferably 98 to 100%, and 99. More preferably, it is -100%.
In the present disclosure, the impregnation rate of the resin with respect to the fiber bundle in the shock absorber can be measured by the method described in Examples described later.

<Tensile strength of shock absorber>
When the continuous reinforcing fiber resin composite is a woven fabric, the tensile strength of the impact absorber of this embodiment is preferably 350 to 800 MPa, and more preferably 400 to 500 MPa. When the continuous reinforcing fiber resin composite is a knitted fabric, it is preferably 280 MPa or more, more preferably 350 MPa or more. Moreover, when a continuous reinforcement fiber resin composite material is a braid, it is preferable that it is 340 Mpa or more, and it is more preferable that it is 400 Mpa or more.
In the present disclosure, the tensile strength of the shock absorber can be measured by the method described in Examples described later.

<Rigidity of shock absorber>
The rigidity of the shock absorber (particularly the cylindrical body portion) of the present embodiment is preferably 10 to 40 GPa, more preferably 20 to 40 GPa. If the rigidity exceeds 40 GPa, other parts of the vehicle body (for example, the frame) may be destroyed when the vehicle receives an impact, causing damage to the person on board. Further, when the rigidity is 40 GPa or less, energy absorption due to the tensile stress of the fiber is likely to occur without buckling.
The said rigidity can be adjusted with the kind of resin, content, impregnation rate, the kind of continuous reinforcement fiber, etc., for example.
In addition, the said rigidity means the value measured by the method based on JISK7171.

<Method for producing shock absorber>
The impact absorber of the present embodiment can be manufactured by placing a continuous reinforcing fiber resin composite material, which will be described later, on a mold and heating and pressing.
It is preferable that the temperature of the mold is set to be equal to or higher than the melting point of the resin contained in the continuous reinforcing fiber-resin composite or the glass transition temperature, and is always adjusted to a constant temperature. The mold clamping pressure is not particularly limited, but is preferably 1 MPa or more, more preferably 3 MPa or more.

  The number of continuous reinforcing fiber resin composites to be installed in the mold can be adjusted depending on the thickness of the intended shock absorber. The portions of the shock absorber that are partially different in thickness can also be adjusted by partially increasing or decreasing the number of continuous reinforcing fiber resin composites installed in the mold. That is, the thickness can be adjusted by installing a larger number of continuous reinforcing fiber resin composites in the thick part than in the thin part. Further, the change in the thickness of the shock absorber can be adjusted by flowing the melt of the thermoplastic resin by the compression molding pressure even when the number of continuous reinforcing fiber resin composites is the same.

  The same type of continuous reinforcing fiber resin composite material installed in the mold may be stacked, but depending on the target strength of the resulting shock absorber, different types of continuous reinforcing fiber resin composite materials may be stacked. It may be installed in a mold. For example, a continuous reinforcing fiber resin composite material made of continuous glass fiber and thermoplastic resin and a continuous reinforcing fiber resin composite material made of continuous aramid fiber and thermoplastic resin may be stacked. Furthermore, it is also possible to overlap a resin film etc. as needed.

  The shock absorber of this embodiment is composed of a continuous reinforcing fiber resin composite material including a fiber bundle containing continuous reinforcing fibers and a resin, and the fiber bundles are fibers having different fiber directions by weaving, knitting, or assembling. It is preferred that the bundles are oriented so as to constrain each other.

<Continuous reinforced fiber resin composite>
The continuous reinforcing fiber resin composite material constituting the shock absorber of the present embodiment includes a fiber bundle including continuous reinforcing fibers and a resin. The whole or part of the fiber bundle is preferably impregnated with 40 to 70%, more preferably 50 to 65% by volume of the resin, and it is preferable that the fiber bundle is solidified.

《Fiber bundle》
The fiber bundle included in the continuous reinforcing fiber resin composite material preferably includes continuous reinforcing fibers and is oriented so that fiber bundles having different fiber directions are constrained by weaving, knitting, or braiding. .
The fiber bundle preferably has a plurality of bundles of a plurality of continuous reinforcing fibers, and preferably has a bundle of continuous reinforcing fibers having 30 to 15000 single yarns from the viewpoint of easy impregnation and handling. Here, the fiber bundle can be confirmed as a region where the continuous reinforcing fibers in the cross section of the continuous reinforcing fiber resin composite material are densely packed. For example, the fiber bundle may be a region where the outer periphery of the dense continuous reinforcing fiber is tied.

[Continuous reinforcing fiber]
The continuous reinforcing fiber may be formed from a reinforcing fiber alone, a mixed yarn in which a thermoplastic resin fiber is entangled with a reinforcing fiber by an interlace or the like, and a reinforcing fiber is used as a core material, and a thermoplastic braid is formed around it. A string-like composite substrate (microblading yarn) coated with resin fibers, a string-like composite substrate (covering yarn) coated with thermoplastic resin fibers in the form of a twisted string around a reinforcing fiber as a core material, Alternatively, the composite yarn may be in any form of a coated yarn in which a reinforcing fiber is coated with a thermoplastic resin, or an impregnated yarn in which a reinforcing fiber is impregnated with a thermoplastic resin. In terms of handling, from the viewpoint of preventing damage and fraying of the continuous reinforcing fiber bundle, when the fiber bundle is made into a woven fabric or knitted fabric, it is preferably a coated yarn in which the glass fiber is not exposed. A coated yarn is preferred.

[[Reinforcing fiber]]
The reinforcing fiber contained in the continuous reinforcing fiber is preferably a fiber having no yield point from the viewpoint of obtaining an impact absorber having a higher absorbed energy amount.
Further, from the viewpoint of impact absorbability, the tensile elastic modulus of the reinforcing fiber measured according to JIS K7127 is preferably 15 GPa or more.
Moreover, from the viewpoint of energy absorption at the time of destruction, the tensile strength of the reinforcing fiber measured in accordance with JIS K7161 is preferably 350 MPa or more.
In the present disclosure, “having no yield point” refers to a curve in which stress continues to increase as strain increases in a stress-strain curve diagram, and fibers having no yield point break. If the load is removed, the original shape is restored.

  Specific examples of such reinforcing fibers include glass fibers, aramid fibers, ultra-high strength polyethylene fibers, liquid crystal polyester fibers, polyketone fibers, ceramic fibers, and polycarbonate fibers. Among these, glass fiber is preferable from the viewpoints of heat resistance, nonflammability, flexibility, cost, handleability, and the like.

When glass fiber is selected as the reinforcing fiber, a sizing agent may be used, and the sizing agent is preferably composed of a silane coupling agent, a lubricant, and a binding agent.
There is no restriction | limiting in particular about the kind of sizing agent used for glass fiber and glass fiber, A well-known thing can be used. Specifically, for example, those described in JP-A-2015-101794 can be used.

  Even when other reinforcing fibers are used, the type and amount of sizing agent that can be used for the glass fibers can be appropriately selected and used according to the characteristics of the reinforcing fibers.

  The number of single yarns of the reinforcing fibers is preferably 100 or more per one from the viewpoint of productivity, and the fineness of the reinforcing fibers is preferably 2000 dtex or more from the viewpoint of productivity. However, this does not exclude out of scope.

[[Thermoplastic resin]]
The thermoplastic resin that may be contained in the fiber bundle is not particularly limited, and examples thereof include polyolefin resins such as polyethylene and polypropylene; polyamide resins such as polyamide 6, polyamide 66, and polyamide 46; polyethylene terephthalate and polybutylene terephthalate. Polyester resins such as polytrimethylene terephthalate; Polyacetal resins such as polyoxymethylene; Polycarbonate resins; Polyether ketones; Polyether ether ketones; Polyether sulfones; Polyphenylene sulfides; Thermoplastic polyether imides; Examples thereof include thermoplastic fluororesins such as ethylene copolymers, and modified thermoplastic resins obtained by modifying these. Among these thermoplastic resins, crystalline resins are preferable, for example, polyolefin resins, polyamide resins, polyester resins, polyether ketones, polyether ether ketones, polyether sulfones, polyphenylene sulfides, thermoplastic polyether imides, In view of mechanical properties and versatility, polyolefin resins, modified polyolefin resins, polyamide resins, and polyester resins are more preferable. From the viewpoint of thermal properties, polyamides are preferable. Of these, polyester resins and polyester resins are more preferable. Further, from the viewpoint of durability against repeated load loading, a polyamide-based resin is more preferable, and polyamide 66 can be suitably used.
These resins may be used alone or as a mixture of two or more.

-Polyester resin-
The polyester-based resin means a high molecular compound having a —CO—O— (ester) bond in the main chain. For example, polyethylene terephthalate, polybutylene terephthalate, polytetramethylene terephthalate, poly-1,4-cyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate and the like can be mentioned, but are not limited thereto. .
Regarding the details of other polyester resins, those described in JP-A-2015-101794 can be used as appropriate.

-Polyamide resin-
The polyamide-based resin means a polymer compound having a —CO—NH— (amide) bond in the main chain. Examples thereof include polyamides obtained by ring-opening polymerization of lactam, polyamides obtained by self-condensation of ω-aminocarboxylic acid, polyamides obtained by condensing diamine and dicarboxylic acid, and copolymers thereof. It is not limited to.
As the polyamide, one kind may be used alone, or two or more kinds may be used as a mixture.
Regarding the details of the other lactam, diamine (monomer), and dicarboxylic acid (monomer), those described in JP-A-2015-101794 can be used as appropriate.

  Specific examples of the polyamide include, for example, polyamide 4 (poly α-pyrrolidone), polyamide 6 (polycaproamide), polyamide 11 (polyundecanamide), polyamide 12 (polydodecanamide), and polyamide 46 (polytetramethylene adipa). Amide), polyamide 66 (polyhexamethylene adipamide), polyamide 610, polyamide 612, polyamide 6T (polyhexamethylene terephthalamide), polyamide 9T (polynonamethylene terephthalamide), and polyamide 6I (polyhexamethylene isophthalamide) And copolymerized polyamides containing these as constituents.

  Examples of the copolymerized polyamide include a copolymer of hexamethylene adipamide and hexamethylene terephthalamide, a copolymer of hexamethylene adipamide and hexamethylene isophthalamide, and hexamethylene terephthalamide and 2-methylpentanediamine terephthalate. Examples include amide copolymers.

The manufacturing method of the said mixed fiber is not restrict | limited in particular, A well-known mixed fiber method can be utilized. For example, after opening by external force due to electrostatic force, pressure by fluid spraying, pressure applied to rollers, etc., then opening and combining yarns in which the reinforcing fiber and thermoplastic resin fiber are opened and aligned, Or the fluid entanglement (interlace) method is mentioned. Among them, a fluid entanglement method that can suppress damage to the reinforcing fibers, has excellent fiber opening properties, and can be mixed uniformly is preferable. As the fluid entanglement method, two or more vortex turbulent zones by fluids such as air, nitrogen gas and water vapor are made almost parallel to the yarn axis, and fibers are guided to this zone so that loops and crimps do not occur. Non-bulky yarn under tension, method of fluid entanglement after opening only reinforcing fibers, or after opening both reinforcing fibers and thermoplastic resin fibers (fluid entanglement method after opening) Is mentioned. In particular, it is preferable that the thermoplastic resin fiber is subjected to false twisting in a process including thermal processing alone, and then continuously blended by the fluid entanglement method in the same apparatus.
In addition, about the detail of the fiber mixing method, the method of Unexamined-Japanese-Patent No. 2015-101794 can be used suitably.

  Moreover, the manufacturing method of the said micro braiding thread | yarn, a covering thread | yarn, a coating thread | yarn, and an impregnation thread | yarn is not restrict | limited, A well-known method can be utilized. The coating and impregnation may be performed at the time of manufacturing the continuous reinforcing fiber bundle, or may be performed in a separate process after the continuous reinforcing fiber bundle is manufactured.

  When the fiber bundle is composed of a composite yarn of reinforcing fiber and thermoplastic resin, the content of the reinforcing fiber in the composite yarn is not particularly limited, but is preferably in the range of 40 to 70% in volume fraction. It can be set appropriately according to the desired strength and rigidity.

[Other additives]
You may make the said fiber bundle contain an additive as needed. The fiber bundle includes, for example, an anti-aging agent, an antioxidant, a weathering agent, a metal deactivator, a light stabilizer, a heat stabilizer, an ultraviolet absorber, an antibacterial / antifungal agent, a deodorant, a conductivity imparting agent, Dispersant, softener, plasticizer, crosslinking agent, co-crosslinking agent, vulcanizing agent, vulcanization aid, foaming agent, foaming aid, colorant, flame retardant, vibration damping agent, nucleating agent, neutralizing agent, You may contain additives, such as a lubricant, an antiblocking agent, a dispersing agent, a fluid improvement agent, and a mold release agent.
The content of the additive may be 10% by mass or less with respect to 100% by mass in total of the continuous reinforcing fiber and the thermoplastic resin.

《Fiber bundle structure》
The fiber bundle has a structure in which fiber bundles having different fiber directions are oriented so as to constrain each other by weaving, knitting, or braiding.
The constraint between the fiber bundles is preferably such that the average density at the point where the fiber bundles intersect is 3 to 13 / cm ^{2 when} viewed from any direction. When the fiber bundle has a planar portion by weaving, knitting, or braiding, it is viewed from the thickness direction of the plane.

When the structure of the fiber bundle is formed by weaving, a woven structure in which the fiber bundle forming the warp and the fiber bundle forming the weft intersect according to a certain rule is obtained. By this intersection, fiber bundles (warp and weft) having different fiber directions are constrained to each other.
The weaving method is not particularly limited, and known methods such as plain weaving, twill weaving, satin weaving, weaving weaving, and wrinkling can be used. A twill weave is preferred from the viewpoint of elasticity and less wrinkling.
The warp density is preferably 30 to 35 yarns / inch, and the weft density is preferably 30 to 35 yarns / inch.

When the above structure of the fiber bundle is formed by knitting, it is formed by continuously forming a loop with one or several fiber bundles and then hooking the next fiber bundle onto the loop to form a new loop. Knitting structure. By this loop, it becomes a structure where the fiber bundle which has a mutually different fiber direction restrains each other.
The method of knitting is not particularly limited, and examples thereof include known methods such as weft knitting, warp knitting, and Raschel knitting. Raschel knitting is preferred from the viewpoint of elasticity and less wrinkling.
The basis weight of the knitted structure is preferably 550 to 650 g / m ² .

When the above-described structure of the fiber bundle is formed by a braid, a braid structure in which three or more fiber bundles are alternately crossed obliquely according to a certain rule. Due to this oblique intersection, fiber bundles having different fiber directions are constrained to each other.
The method of assembling is not particularly limited, and examples thereof include known methods such as round punching, square punching, and flat punching.
The crossing angle of the fiber bundles in the braided structure is preferably 45 to 90 degrees.

  The content of the fiber bundle with respect to 100% by mass of the continuous reinforcing fiber resin composite material is preferably 60 to 85% by mass, and more preferably 70 to 80% by mass.

"resin"
The resin contained in the continuous reinforcing fiber resin composite is not particularly limited as long as the effects of the present invention are not impaired, and may be a thermoplastic resin or a thermosetting resin.

  There is no restriction | limiting in particular as a thermoplastic resin which can be contained in the said continuous reinforcement fiber resin composite material, The thing similar to the thermoplastic resin which may be contained in the above-mentioned fiber bundle can be used suitably.

  The thermosetting resin that can be included in the continuous reinforcing fiber resin composite is not particularly limited. For example, epoxy resin, thermosetting modified polyphenylene ether resin, thermosetting polyimide resin, urea resin, allyl resin, silicon resin , Benzoxazine resin, phenol resin, unsaturated polyester resin, bismaleimide triazine resin, alkyd resin, furan resin, melamine resin, polyurethane resin, aniline resin, other industrially available resins, and two types of these resins Examples thereof include resins obtained by mixing the above. Of these, phenol resin resins and epoxy resin resins are preferred from the viewpoints of heat resistance and flame retardancy.

  The resin content relative to 100% by mass of the continuous reinforcing fiber resin composite material is preferably 25 to 40% by mass, and more preferably 20 to 30% by mass.

《Other additives》
The continuous reinforcing fiber resin composite material may contain an additive as necessary. The continuous reinforcing fiber resin composite material is, for example, anti-aging agent, antioxidant, weathering agent, metal deactivator, light stabilizer, heat stabilizer, ultraviolet absorber, antibacterial / antifungal agent, deodorant, conductive Property-imparting agent, dispersant, softener, plasticizer, crosslinking agent, co-crosslinking agent, vulcanizing agent, vulcanization aid, foaming agent, foaming aid, colorant, flame retardant, vibration damping agent, nucleating agent, You may contain additives, such as a neutralizing agent, a lubricant, an antiblocking agent, a dispersing agent, a fluidity improver, and a mold release agent.
The content of the additive may be 10% by mass or less with respect to 100% by mass of the continuous reinforcing fiber resin composite material.

<Method for producing continuous reinforcing fiber resin composite>
For example, when the continuous reinforcing fiber resin composite material is manufactured as a woven fabric obtained by weaving a composite yarn composed of reinforcing fibers and thermoplastic resin fibers, a shuttle loom, a rapier loom, an air jet A loom such as a loom or a water jet loom can be used as long as it includes at least a composite yarn composed of a reinforcing fiber and a thermoplastic resin. Preferably, it may be obtained by driving a weft into a warp in which fibers including a composite yarn are arranged.
In addition, when producing a continuous reinforcing fiber resin composite material as a knitted fabric knitted with a composite yarn composed of reinforcing fibers and thermoplastic resin fibers, for example, a knitting machine such as a circular knitting machine, a flat knitting machine, a tricot knitting machine, a Raschel knitting machine, etc. It is only necessary that at least a part of the fiber includes a composite yarn composed of a reinforcing fiber and a thermoplastic resin.
When manufacturing a continuous reinforcing fiber resin composite material as a braid made of a composite yarn composed of a reinforcing fiber and a thermoplastic resin fiber, for example, a braid of a tubular braiding machine or the like for 8 strokes, 16 strokes, hammering, etc. It is sufficient that at least a part of the machine includes a fiber including a composite yarn composed of a reinforcing fiber and a thermoplastic resin.
These are heated to melt only the thermoplastic resin, and the reinforcing fibers are impregnated with the resin.
The continuous reinforcing fiber resin composite material is obtained by impregnating a fiber base material obtained by weaving, knitting, or stringing a fiber bundle made of reinforcing fibers with a thermoplastic resin and / or a thermosetting resin. It may be manufactured. The impregnation method of the resin is not particularly limited, and any known method may be used as long as a good impregnation property is obtained.

  Hereinafter, the contents of the present invention will be described more specifically with reference to examples and comparative examples. The present invention is not limited to these examples.

<material>
The materials used in Examples and Comparative Examples are as follows.

-Reinforcing fiber-
・ Glass fiber (GF) (fineness: 685 dtex, number of single yarns: 400)

-Resin-
Polyamide 66 fiber (PA66-1) (trade name: Leona (registered trademark) 470 / 144BAU, manufactured by Asahi Kasei Fibers, fineness: 470 dtex, number of single yarns: 144, melting point: 265 ° C.)
Polyamide 66 fiber (PA66-2) (trade name: Leona (registered trademark) 56/96 SLM, manufactured by Asahi Kasei Fibers, fineness: 56 dtex, number of single yarns: 96, melting point: 265 ° C.)

-Bundling agent-
-Sizing agent A: It has the following composition (solid content conversion).
Silane coupling agent: 0.6% by mass of γ-aminopropyltriethoxysilane (trade name: KBE-903, manufactured by Shin-Etsu Chemical Co., Ltd.)
・ Lubricant: 0.1% by weight of wax (trade name: Carnauba wax, manufactured by Yoko Kato)
・ Binder: 5% by mass of acrylic acid / maleic acid copolymer salt (trade name: Aqualic TL, manufactured by Nippon Shokubai Co., Ltd.)

<Measurement and evaluation method>
The measurement and evaluation methods used in Examples and Comparative Examples are as follows.

(1) Shock absorption energy of shock absorber The shock absorption energy (kJ) of the shock absorbers obtained in Examples and Comparative Examples was measured according to JIS K7211-1; Specifically, the measurement was performed under the following conditions.
・ Test environment: 23 ℃
・ High-speed impact tester: Shimadzu HYDRO SHOT HITS-P10 (manufactured by Shimadzu Corporation)
-Specimen shape: 60mm square flat plate, wall thickness 2mm
Test speed: 4.4 mm / s
An impact was applied in the axial direction from the tip side.

(2) Impregnation rate of resin in impact absorber The cross section of the impact absorber was cut out, embedded in an epoxy resin, and polished while taking care not to damage the continuous reinforcing fiber. The cross section is observed with a microscope, and the occupied area of each of the fiber bundle, the thermoplastic resin, and the void in the fiber bundle is obtained from the obtained image, and the ratio (%) of the area of the void to the area of the fiber bundle (not yet) The area ratio of the impregnated portion was calculated. Then, the impregnation ratio (%) of the resin was calculated from “100—area ratio of unimpregnated portion”.

(3) Tensile strength of shock absorber According to JIS K7161, a strip-shaped test piece having a length of 70 mm, a width of 10 mm, and a thickness of 2 mm is cut out from an injection molded product, and the test piece is longitudinally measured with an Instron universal testing machine. The sample was chucked at intervals of 30 mm, and the tensile strength (MPa) was measured in a 5 mm / min speed, 23 ° C., 50% RH environment.

[Example 1]
Two bundles of glass fibers to which 1.0% by mass of sizing agent A are adhered and two bundles of polyamide 66 fibers (PA66-1) are combined, aligned, and then supplied substantially vertically to the fluid entanglement nozzle. Fluid entanglement was performed under the following conditions to obtain a composite yarn (Vf of glass fiber: 50%).
-Heat set: Immediately before the alignment, the polyamide fiber was heat-set with a heater at 1 m and a heater at 240 ° C.
-Since the polyamide fiber shrinks due to heat setting, the overfeed amount was adjusted.
・ Since the reinforcing fiber has a small expansion / contraction ratio and yarn swinging easily, the yarn path was adjusted to reduce the yarn swinging.
-Fluid entanglement nozzle: Kyocera KC-AJI-L (1.5 mm diameter, propulsion type)
・ Air pressure: 2kg / cm ²
Processing speed: 100 m / min. Indoor atmosphere was adjusted to 25 ° C. and humidity 50%. Dry air was passed through the winding part to prevent polyamide from absorbing moisture.
A rapier weaving machine was used to weave the twill weave using the composite yarn as warp and weft. The weave density was adjusted so that the basis weight was 630 g / m ² .
Next, the woven fabric obtained above has a shape obtained by halving a regular hexagonal top surface having a side length of 20 mm, a regular hexagonal bottom surface having a side length of 50 mm, a regular hexagonal frustum having a height of 130 mm and a thickness of 2 mm. The above mold was put into a hydraulic molder (50t heating / cooling molding machine manufactured by Shoji Co., Ltd.) which was put into the upper and lower molds (FIG. 7) and heated to 300 ° C., and pressurized and heated under a pressure of 5 MPa.
After the internal temperature reaches 300 ° C. and held for 10 minutes, after cooling to 20 ° C. with water cooling, the mold is put into a hydraulic molding machine and cooled until the internal temperature becomes 30 ° C. or lower. Opened and the molded product was taken out. The obtained molded product was joined by thermocompression bonding to obtain the molded product of FIG.
The regular hexagonal frustum which is the end of the cylindrical body portion had an angle α of about 12 °. Each fiber direction of the fiber bundle in the shock absorber was an angle of 90 ° with respect to the axial direction.
Table 1 shows the physical properties of the shock absorber of Example 1.

[Example 2]
Two bundles of glass fibers to which 1.0% by mass of sizing agent A are adhered and two bundles of polyamide 66 fibers (PA66-1) are combined, aligned, and then supplied substantially vertically to the fluid entanglement nozzle. Fluid entanglement was performed under the following conditions to obtain a composite yarn (Vf of glass fiber: 50%).
-Fluid entanglement nozzle: Kyocera KC-AJI-L (1.5 mm diameter, propulsion type)
・ Air pressure: 2kg / cm ²
・ Processing speed: 3 m / min Five mixed yarns obtained are aligned and used as a braid. Using a 96-pipe tubular braid machine (product name: 101-M, manufactured by Kokbun Limited), the inner diameter is 25 mm. The braid was formed at a braid angle of 45 ° to obtain a hollow braid-like continuous reinforcing fiber resin composite.
Next, after inserting a silicone tube inside the continuous reinforcing fiber resin composite obtained above, a regular hexagonal top surface with a side length of 20 mm, a regular hexagonal bottom surface with a side length of 50 mm, and a height of 40 mm They were placed in an outer mold having an internal dimension in which a regular hexagonal frustum, a top surface and a bottom surface with a side length of 50 mm, and a regular hexagonal column with a height of 90 mm were combined, and heated to 300 ° C. Air of 8 kg / cm ² was sent into the silicone tube to expand the tube, and the composite material was pressed against the outer mold and molded for 30 minutes. After cooling in a pressurized state to room temperature, the molded product is taken out, and the outer surface has a regular hexagonal top surface with a side length of 20 mm, a regular hexagonal bottom surface with a side length of 50 mm, a regular hexagonal frustum with a height of 40 mm, An impact absorber (FIG. 2) consisting only of a hollow cylindrical body portion formed by combining a top surface and a bottom surface with a length of 50 mm on one side and a regular hexagonal column with a height of 90 mm was obtained.
The regular hexagonal frustum that is the end of the cylindrical body portion had an angle α of 15 °. Each fiber direction of the fiber bundle in the shock absorber was at an angle of 45 ° with respect to the axial direction.
Table 1 shows the physical properties of the shock absorber of Example 1.

[Example 3]
A molded body having the shape of FIG. 1A was obtained in the same manner as in Example 1 except that the continuous reinforcing fiber resin composite material obtained in Example 2 was used instead of the woven fabric.
The regular hexagonal frustum which is the end of the cylindrical body portion had an angle α of about 12 °. Each fiber direction of the fiber bundle in the shock absorber was an angle of 90 ° with respect to the axial direction.
Table 1 shows the physical properties of the shock absorber of Example 1.

[Comparative Example 1]
A silicone tube was inserted into the inside of a continuous reinforcing fiber resin composite similar to that in Example 2, and then placed in a cylindrical outer mold having an outer diameter of 90 mm and a height of 130 mm, and heated to 300 ° C. Air of 8 kg / cm ² was sent into the silicone tube, the tube was expanded, the braid was pressed against the outer mold, and molded for 30 minutes. After cooling in a pressurized state to room temperature, the molded product is taken out, and as shown in FIG. 6 (b), a hollow cylindrical shape with outer surface dimensions of an outer diameter of 90 mm, a height of 130 mm, and an angle α of 0 °. A cylindrical body part (impact absorber) was obtained. Each fiber direction of the fiber bundle in the shock absorber was 45 ° with respect to the axial direction.
Table 1 shows the physical properties of the shock absorber of Comparative Example 1.
The shock absorber of Comparative Example 1 was buckled in the middle of measurement of shock absorption energy.

[Comparative Example 2]
Using a continuous reinforcing fiber resin composite material similar to that in Example 2, a molded product having a shape of FIG. 6A having a thickness of 2 mm was obtained.
The shock absorber of Comparative Example 2 buckled in the middle of the measurement of shock absorption energy.

  Also, using the composite yarn of Example 1 above as the fiber bundle and the binding yarn, and the polyamide 66 as the resin, 9 layers of fiber layers in the compression direction (fiber direction having an angle γ of 0 °) and 8 layers of 90 ° fiber layers ( A shock absorber having the same shape and fiber distribution as in FIG. 2 of JP-A No. 2005-193755 was produced, which was composed of a binding yarn and an angle γ of 90 °. When the impact energy test of the above (1) shock absorber was conducted, each layer was peeled off, and the energy absorption was mainly delamination.

  The shock absorber of this embodiment is excellent in shock absorption and lightweight, and is particularly suitable for application to vehicles such as automobiles equipped with bumper beams and the like on the front and rear sides.

DESCRIPTION OF SYMBOLS 1 Shock absorber 2 Hollow cylindrical body part 21 End part 22 One end (tip) of an axial direction
22a Outer surface side end 22b Inner surface side end 23 Axial other end (base end)
24 Outer surface 25 Inner surface 26 Axis 3 Flat plate AD Axial direction

Claims (7)

A shock absorber having a hollow cylindrical body portion made of a continuous reinforcing fiber resin composite material containing a fiber bundle containing continuous reinforcing fibers and a resin,
One end of the cylindrical body portion in the axial direction is an end where an angle α between the axial direction of the cylindrical body portion and a direction along the outer surface of the cylindrical body portion is 0.1 to 30 °. A shock absorber characterized by having an end.   The shock absorber according to claim 1, wherein the shape of the end portion of the cylindrical body portion is an n-pyramidal frustum (n is an integer of 3 or more) or a truncated cone.   The shock absorber according to claim 1 or 2, wherein the angle α is 0.1 to 30 ° from the one end in the axial direction to the other end in the axial direction.   The impact absorber according to any one of claims 1 to 3, wherein at least one of the fiber directions of the fiber bundle forms an angle greater than 0 ° and less than 90 ° with respect to the axial direction.   The impact absorber according to any one of claims 1 to 4, wherein the fiber bundles are oriented such that fiber bundles having different fiber directions are constrained by weaving, knitting, or braiding.   The impact absorber according to any one of claims 1 to 5, wherein at least a part of the plurality of continuous reinforcing fiber resin composite materials are laminated.   The impact absorber according to any one of claims 1 to 6, wherein the reinforcing fiber contained in the continuous reinforcing fiber is a fiber having no yield point.

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