JP2015175430A - Resin shock absorption member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-weight resin sock absorption member freely designing a shock absorption characteristic easily.SOLUTION: A resin shock absorption member includes a shock absorption part whose thickness is made substantially constant and which comprises a shock absorption base material. The shock absorption base material is configured such that a plurality of thermoplastic resin base materials having different compression strength in a shock absorption direction are connected.

Description

  The present invention relates to a resin impact absorbing member made of a resin material, and more particularly to a resin impact absorbing member using a thermoplastic resin.

  In a vehicle or the like, an impact absorbing member is generally used to prevent an impact applied to the vehicle at the time of a collision from being transmitted directly to the vehicle skeleton or the driver. For example, in a passenger car, an impact absorbing member is used inside a bumper at the front and rear of the vehicle. As such an impact absorbing member, conventionally, a metallic impact absorbing member made of a metal material has been used. As a structure of a metal shock absorbing member, for example, a steel material having a structure in which a steel material is press-molded and formed into a box shape by spot welding or the like and provided with a recess serving as a buckling start point (for example, Patent Document 1). In addition, from the viewpoint of weight reduction, it has a structure in which a box shape is formed using an extruded aluminum material instead of steel, a recess that becomes a buckling starting point is provided in post-processing, and a mounting portion with other parts is provided by welding. A thing is also known (for example, patent document 2).

  In recent years, with the progress of the development of electric vehicles and the like, it is desired to reduce the weight of the vehicle structure for the purpose of improving the fuel efficiency, and further reduction of the weight of the impact absorbing member is also desired. However, when the shock absorbing member is made of a metal material, there is a limit to the extent that the weight can be reduced in practice, and it has been pointed out that it is difficult to achieve further weight reduction.

  In view of the problem of such a metal impact absorbing member, investigation of a resin impact absorbing member made of a resin material is underway (for example, Patent Document 3). Since the resin shock absorbing member uses a light resin material instead of the conventional metal material, it has the advantage that the resin shock absorbing member can be significantly reduced in weight. It is expected as a means to further reduce weight.

Japanese Patent Laid-Open No. 2-175252 JP-A-2005-001462 JP 2005-247096 A

  By the way, since the resin shock absorbing member is made of a single resin material, there is a possibility that a sudden load is generated at the time of absorbing the shock or the shock absorbing performance as originally designed cannot be obtained. In addition, the shock absorbing characteristic is insufficient as compared with a metal shock absorbing member, such as an air bag actuation sensor that cannot perform the function of absorbing shock corresponding to at least two levels of collision speed. Due to the tendency, a problem has been pointed out that depending on the application of the impact absorbing member, the intended impact absorbing characteristic cannot be achieved with the resin impact absorbing member.

  In order to solve such problems, the shock absorbing characteristics of the resin shock absorbing member are optimized by making the strength of the rear end portion stronger than the strength of the tip portion to which the shock is applied in the resin shock absorbing member. A method is being considered. As a specific method, for example, a method in which the thickness of the rear end portion is made larger than the front end portion to which an impact is applied has been studied. However, in such an aspect in which the thickness is changed, (1) when a large impact or an impact from an oblique direction is applied, the boundary of the thickness becomes a starting point of destruction, and sufficient shock absorption characteristics cannot be exhibited. ) Since the thickness in the vicinity of the tip part that receives the impact is reduced, the attachment part with peripheral parts becomes fragile. (3) The resin-made shock absorbing member is generally manufactured by a press molding method. When changing the boundary of thickness or changing the overall thickness in order to cope with changes in the amount of energy to be applied, it is necessary to change the press molding die each time. It is difficult to change the design and manufacture. (4) When a large amount of fluid molding is performed using a fiber reinforced resin material mixed with fiber as the resin material, fiber orientation occurs during press molding. There has been a problem such as that performance can not be obtained.

  The present invention has been made in view of such problems, and it is mainly intended to provide a resin-made shock absorbing member that is made of a resin material and that is easy to design with light weight and shock absorbing characteristics. It is the purpose.

  In order to solve the above-mentioned problems, the present invention provides a resin-made shock absorbing member including a shock absorbing portion formed of a shock absorbing base material having a substantially constant thickness, wherein the shock absorbing base material has a shock absorbing direction. And a plurality of thermoplastic resin base materials having different compressive strengths are bonded to each other.

According to the resin shock-absorbing member of the present invention, when the shock is applied to the resin shock-absorbing member of the present invention, since the thickness of the shock-absorbing base material is substantially constant, Regardless of the direction, the boundary between a plurality of thermoplastic resin substrates having different compressive strengths in the shock-absorbing substrate can be prevented from becoming a starting point of fracture. For this reason, excellent impact absorbing performance can be exhibited regardless of the degree of impact applied to the resin impact absorbing member of the present invention, the direction in which the impact is applied, and the like.
Further, in the present invention, the shock absorbing base material is formed by combining a plurality of thermoplastic resin base materials having different compressive strengths, so that the thickness of the shock absorbing base material is not changed. Regions having different compressive strengths can be formed. For this reason, for example, the position of the boundary of the thermoplastic resin base material can be adjusted without changing the press die, and the design and control of the shock absorbing performance can be freely performed.

  In the resin shock absorbing member of the present invention, the plurality of thermoplastic resin base materials in the shock absorbing base material are arranged in order of increasing compressive strength from the front end side to the rear end side receiving the impact. It is preferable. As a result, the impact strength of the impact absorbing portion can be increased as the impact absorbing portion progresses, so when a load is applied to the impact absorbing portion, the failure begins gradually from the tip portion having a low compressive strength. This is because the fracture site can be propagated to the side with high compressive strength. In addition, since the portions having different compressive strengths can be compressed and destroyed in response to a plurality of compressive loads, it is possible to effectively suppress the impact absorbing portion from being completely collapsed by an external impact. is there. Further, it is possible to absorb the impact continuously while maintaining a substantially constant impact absorbing performance during the compressive load.

  In the resin impact absorbing member of the present invention, it is preferable that the plurality of thermoplastic resin substrates are made of a fiber reinforced thermoplastic resin composite material containing reinforcing fibers and a thermoplastic resin. This is because by using the fiber reinforced thermoplastic resin composite material, the resin impact absorbing member of the present invention can be further reduced in weight and the manufacturing cost can be reduced. When such a fiber-reinforced thermoplastic resin composite material is used, it is preferable that the plurality of thermoplastic resin base materials have different compressive strengths due to different volume contents of the reinforcing fibers.

  In the resin impact absorbing member of the present invention, the impact absorbing base material is bonded so that adjacent thermoplastic resin base materials continuously change in the thickness direction at the boundary. It is preferable. When the adjacent thermoplastic resin base materials are bonded in such a manner, regardless of the magnitude of the impact or the direction of the impact, when the impact is applied to the resin impact absorbing member of the present invention in the impact absorbing direction. This is because the boundary of the thermoplastic resin base material can be further suppressed from becoming the starting point of destruction.

  Furthermore, in the resin shock absorbing member of the present invention, it is preferable that the shock absorbing portion has a cylindrical shape having a hollow structure. As a result, although it is light in weight, it is possible to cause breakage at the time of shock absorption in all parts over the entire circumference of the resin shock absorbing member, so that a large shock is absorbed by continuous and stable breakage. This is because the shock absorbing efficiency per member weight of the resin shock absorbing member is improved.

  The resin shock absorbing member of the present invention has an effect that it is lightweight and can freely design shock absorbing characteristics.

It is the schematic which shows an example of the resin impact-absorbing member of this invention. It is the schematic which shows an example of the coupling | bonding aspect of the thermoplastic resin base material in this invention. It is the schematic which shows an example of the aspect by which the thermoplastic resin base material is arrange | positioned in the impact-absorbing base material in this invention. It is the schematic which shows the other example of the coupling | bonding aspect of the thermoplastic resin base material in this invention. It is the schematic which shows an example in case the impact-absorbing part in this invention is plate shape. It is the schematic which shows an example in case the impact-absorbing part in this invention is cylindrical. It is the schematic which shows the other example of the resin-made impact-absorbing members of this invention. It is the schematic which shows the other example of the resin-made impact-absorbing members of this invention. It is the schematic of the impact-absorbing part in the resin-made impact-absorbing members of an Example.

The resin impact absorbing member of the present invention will be described below.
As described above, the resin-made shock absorbing member of the present invention is a resin-made shock absorbing member including a shock-absorbing portion composed of a shock-absorbing base material having a substantially constant thickness. A plurality of thermoplastic resin base materials having different compressive strengths in the absorption direction are combined.

  Here, the “impact absorption direction” in the present invention refers to a direction from the front end side where the shock absorbing portion receives an impact toward the rear end side when an impact is input from the outside to the resin shock absorbing member of the present invention. It means the direction of being crushed. When the shock absorbing portion in the resin shock absorbing member of the present invention has a cylindrical shape having a hollow structure, the shock absorbing direction is usually parallel to the axial direction of the hollow structure.

  Such a resin impact absorbing member of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an example of a resin impact absorbing member of the present invention. FIG. 1B is a cross-sectional view taken along line YY ′ of FIG. As illustrated in FIGS. 1A and 1B, a resin impact absorbing member 10 of the present invention includes an impact absorbing portion 12 composed of an impact absorbing base material 11 having a substantially constant thickness. The shock-absorbing substrate 11 is characterized in that a plurality of thermoplastic resin substrates 11a and 11b having different compressive strengths in the shock-absorbing direction X are combined. Here, the thermoplastic resin base materials 11a and 11b in FIG. 1 have mutually different compressive strengths (hereinafter the same in this specification).

  According to the resin shock-absorbing member of the present invention, the thickness of the shock-absorbing base material is substantially constant, so that the compressive strength is different in the shock-absorbing base material regardless of the magnitude or direction of the shock. It can prevent that the boundary of a some thermoplastic resin base material becomes a starting point of destruction. For this reason, excellent impact absorbing performance can be exhibited regardless of the degree of impact applied to the resin impact absorbing member of the present invention. Further, in the present invention, the shock-absorbing base material is formed by combining a plurality of thermoplastic resin base materials having different compressive strengths, so that the thickness of the shock-absorbing base material is not changed. Regions having different compressive strengths can be formed. For this reason, for example, it is possible to adjust the position of the boundary without changing the press die, and it is possible to freely design and control the shock absorbing performance. Furthermore, in the present invention, the impact-absorbing substrate is made of a thermoplastic resin substrate, so that the weight can be significantly reduced as compared with a metallic resin-made impact absorbing member. For this reason, according to the present invention, it is possible to obtain a resin-made impact absorbing member that can be designed with light weight and impact absorbing characteristics.

  The resin impact absorbing member of the present invention includes an impact absorbing portion having the above-described characteristics. Hereafter, each structure used for the resin impact-absorbing member of this invention is demonstrated in order.

1 Shock Absorbing Part First, the shock absorbing part in the present invention will be described. The impact absorbing portion in the present invention is composed of an impact absorbing base material.

(1) Shock Absorbing Base Material The shock absorbing base material of the present invention is characterized in that a plurality of thermoplastic resin base materials having substantially constant thickness and different compressive strengths in the shock absorbing direction are combined. To do.
In the present invention, “the thickness of the shock-absorbing base material is substantially constant” means that the average thickness of the plurality of thermoplastic resin base materials constituting the shock-absorbing base material is substantially constant. . As described above, since the average thickness of each thermoplastic resin base material is substantially constant, in the resin impact absorbing member of the present invention, when an impact is applied from the outside to the impact absorbing portion, the magnitude of the impact and the impact are reduced. Regardless of the direction, it is possible to suppress the boundary portion of the thermoplastic resin base material from being a starting point of breakage, and it is easy to attach the peripheral part.

  Further, the above “the thickness of the thermoplastic resin base material is substantially constant” does not mean that the thickness of each thermoplastic resin base material is completely the same, regardless of the magnitude or direction of the impact. When the impact is applied to the resin impact absorbing member of the present invention from the outside, due to the difference in the thickness of each thermoplastic resin base material, the boundary between the thermoplastic resin base materials does not become a starting point of destruction. This means that the average thicknesses of the thermoplastic resin substrates are close to each other.

  More specifically, the difference in average thickness of each thermoplastic resin substrate used in the present invention is preferably ± 10% or less, and more preferably ± 5% or less. When the difference in the average thickness of each thermoplastic resin substrate is within such a range, regardless of the magnitude of the impact and the direction of the impact, when an impact is applied to the resin impact absorbing member of the present invention from the outside. This is because it is possible to suppress the boundary between the thermoplastic resin substrates from becoming the starting point of destruction due to the difference in the average thickness of each thermoplastic resin substrate. Here, the average thickness of each thermoplastic resin base material is, for example, the caliper of the thickness at the three points of the front half, the middle part, and the rear half from the front end side to the rear end side receiving the impact of each thermoplastic resin base material. It can be determined by measuring with a micrometer or the like and determining the average value.

  The average thickness of each thermoplastic resin substrate used in the present invention can be appropriately determined within a range in which a desired shock absorbing characteristic can be realized according to the use of the resin shock absorbing member of the present invention. Although not particularly limited, it is usually preferably in the range of 1 mm to 10 mm, and more preferably in the range of 2 mm to 8 mm.

  The impact-absorbing base material in the present invention is formed by combining a plurality of thermoplastic resin base materials having different compressive strengths. The compressive strength of each thermoplastic resin base material is a desired impact-absorbing characteristic in the impact-absorbing portion. If it is in the range which can provide, it will not specifically limit, It can adjust suitably by design. Here, the compressive strength of the thermoplastic resin substrate can be measured by, for example, the method described in JIS K7076.

  The aspect in which a plurality of thermoplastic resin bases having different compressive strengths are combined in the impact-absorbing base is particularly limited as long as adjacent thermoplastic resin bases can be combined with a desired strength or more. It is not a thing. Examples of the bonding mode used in the present invention include, for example, a mode in which end faces of adjacent thermoplastic resin substrates are bonded to each other (bonding mode i), and a part of end portions of adjacent thermoplastic resin substrates are overlapped. A bonded mode (bonded mode iii), and a mode in which adjacent thermoplastic resin base materials are bonded so that the existence ratio in the thickness direction continuously changes at the boundary (bonded mode iii), etc. Can be mentioned. Each of these aspects will be described with reference to the drawings. FIG. 2 is a schematic diagram illustrating an example of each of the above coupling modes. As illustrated in FIG. 2, as an aspect in which the thermoplastic resin base material is bonded in the present invention, the end surfaces of the thermoplastic resin base materials 11 a and 11 b as illustrated in FIG. 2A are bonded to each other. The mode (bonding mode i) may be used, and the end portions of the thermoplastic resin base materials 11a and 11b as illustrated in FIGS. 2B and 2C are combined so as to be partially overlapped. (Bonding mode ii) may be used, or as shown in FIGS. 2D and 2E, the thermoplastic resin base materials 11a and 11b continuously change in the thickness direction at the boundary. It may be a mode (bonding mode iii) bound to.

  In the present invention, any of the above-described bonding modes can be preferably used, and among these, the bonding mode iii is preferably used. When the adjacent thermoplastic resin base material is bonded by the bonding mode iii, regardless of the magnitude of the impact or the direction of the impact, when an impact is applied to the resin impact absorbing member of the present invention from the impact absorbing direction, It is because it can further suppress that the boundary part of a thermoplastic resin base material becomes a starting point of destruction.

  In addition, about the method of implementing each said coupling | bonding aspect, the coupling | bonding aspect i prepares the 2 types of thermoplastic resin base materials from which compressive strength differs, for example, The mold which designed these 2 types of thermoplastic resin base materials previously An example is a method in which the end portion is brought into contact with a predetermined position in the inside and press-molded. The bonding mode ii is, for example, preparing two types of thermoplastic resin base materials having different compressive strengths, forming a step on the end surface of each thermoplastic resin base material, and then setting the end surface at a predetermined position in a pre-designed mold. An example is a method in which the steps are placed so as to overlap each other and press-molded. In addition, in the bonding mode iii, for example, two types of thermoplastic resin base materials having different compressive strengths are prepared, and the two end portions of the two thermoplastic resin base materials are overlapped at predetermined positions in a pre-designed mold. And a method of joining two kinds of thermoplastic resin base materials by causing the overlapping portion to flow during press molding. In either case, after the thermoplastic resin base materials having different compressive strengths are separately molded in advance, the welding is performed by thermal welding such as vibration welding or ultrasonic welding, or by a mechanical fastening method such as an adhesive, a bolt or a nut. Surfaces can also be combined.

  The impact-absorbing base material in the present invention is formed by combining a plurality of thermoplastic resin base materials having different compressive strengths in the shock absorbing direction, but as an aspect in which a plurality of thermoplastic resin base materials are arranged in the shock absorbing direction, The present invention is not particularly limited as long as it can provide desired shock absorption characteristics to the shock absorbing portion in the present invention. Especially, in this invention, the aspect arrange | positioned in order with a high compressive strength along a shock absorption direction is preferable. By arranging a plurality of thermoplastic resin base materials having different compressive strengths in this manner, the impact strength of the impact absorbing portion can be increased as the impact absorbing portion progresses. It is because it can suppress effectively that an absorption part collapses completely. Here, “the order in which the compressive strength increases along the shock absorption direction” is the order in which the compressive strength increases from the front end side receiving the impact toward the rear end side.

Such an arrangement mode of the thermoplastic resin base material will be described with reference to the drawings. FIG. 3 shows a case in which a plurality of thermoplastic resin base materials having different compressive strengths are arranged in the order of increasing compressive strength from the front end side to the rear end side receiving an impact in the shock absorbing base material of the present invention It is the schematic which shows an example. As illustrated in FIG. 3, in the shock-absorbing base material 11 according to the present invention, the thermoplastic resin base materials 11 a, 11 b, and 11 c are arranged in the order in which the compressive strength increases from the front end side receiving the impact toward the rear end side. It is preferable that they are arranged. In addition, the thermoplastic resin base materials 11a, 11b, and 11c in FIG. 3 shall have higher compressive strength in this order.
The type of the thermoplastic resin base material constituting the shock-absorbing base material in the present invention is not particularly limited as long as it is 2 or more. You can choose.

In the shock-absorbing substrate in the present invention, the boundary direction between the thermoplastic resin substrates may be any direction as long as it is a direction other than the direction parallel to the shock-absorbing direction, but is substantially perpendicular to the shock-absorbing direction. The direction is preferred. Thereby, the destruction at the time of impact absorption is transmitted equally to the entire circumference, and stable destruction continues continuously at all the parts, and a large impact can be absorbed. Further, the impact absorption efficiency per member weight of the resin shock absorbing member is improved.
Here, the boundary direction between the thermoplastic resin base materials is substantially perpendicular to the shock absorbing direction of the shock absorbing portion, as illustrated in FIG. 4, the thermoplastic resin in the shock absorbing base material 11. It means that the direction ZZ ′ of the boundary between the base materials 11a and 11b is substantially perpendicular to the shock absorption direction X.

(2) Thermoplastic resin base material Next, the thermoplastic resin base material which comprises the shock-absorbing base material used for this invention is demonstrated. The thermoplastic resin substrate used in the present invention contains at least a thermoplastic resin.

A. Thermoplastic resin The thermoplastic resin used for the thermoplastic resin base material is not particularly limited as long as it can impart desired shock absorbing characteristics to the shock absorbing portion depending on the application of the resin shock absorbing member of the present invention. It is not particularly limited. As the thermoplastic resin used in the present invention, one having a softening point in the range of 180 ° C. to 350 ° C. is usually used, but is not limited thereto.

  Examples of the thermoplastic resin used in the present invention include polyolefin resin, polystyrene resin, thermoplastic polyamide resin, polyester resin, polyacetal resin (polyoxymethylene resin), polycarbonate resin, (meth) acrylic resin, polyarylate resin, polyphenylene. Examples include ether resins, polyimide resins, polyether nitrile resins, phenoxy resins, polyphenylene sulfide resins, polysulfone resins, polyketone resins, polyether ketone resins, thermoplastic urethane resins, fluorine-based resins, and thermoplastic polybenzimidazole resins. .

  Examples of the polyolefin resin include polyethylene resin, polypropylene resin, polybutadiene resin, polymethylpentene resin, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, and polyvinyl alcohol resin. Examples of the polystyrene resin include polystyrene resin, acrylonitrile-styrene resin (AS resin), acrylonitrile-butadiene-styrene resin (ABS resin), and the like. Examples of the polyamide resin include polyamide 6 resin (nylon 6), polyamide 11 resin (nylon 11), polyamide 12 resin (nylon 12), polyamide 46 resin (nylon 46), polyamide 66 resin (nylon 66), and polyamide 610. Resin (nylon 610) etc. can be mentioned. Examples of the polyester resin include polyethylene terephthalate resin, polyethylene naphthalate resin, boribylene terephthalate resin, polytrimethylene terephthalate resin, and liquid crystal polyester. Examples of the (meth) acrylic resin include polymethyl methacrylate. Examples of the modified polyphenylene ether resin include modified polyphenylene ether. Examples of the thermoplastic polyimide resin include thermoplastic polyimide, polyamideimide resin, polyetherimide resin, and the like. Examples of the polysulfone resin include a modified polysulfone resin and a polyethersulfone resin. Examples of the polyetherketone resin include polyetherketone resin, polyetheretherketone resin, and polyetherketoneketone resin. As said fluororesin, polytetrafluoroethylene etc. can be mentioned, for example.

  The thermoplastic resin used in the present invention may be only one type or two or more types. In the present invention, as an aspect of using two or more types of thermoplastic resins in combination, for example, an aspect in which thermoplastic resins having different softening points or melting points are used in combination, an aspect in which thermoplastic resins having different average molecular weights are used in combination, etc. This is not a limitation.

(A) Fiber reinforced thermoplastic resin composite material The thermoplastic resin base material used in the present invention may be one in which an arbitrary reinforcing material is used for the thermoplastic resin. As an example of the thermoplastic resin material containing a reinforcing material, for example, a fiber reinforced thermoplastic resin composite material containing a reinforced fiber and a thermoplastic resin can be given. In this invention, it is preferable that such a fiber reinforced thermoplastic resin material is used as a material which comprises a thermoplastic resin base material. The fiber reinforced thermoplastic resin composite material has excellent strength and shock absorption performance while being lightweight, so it can achieve the desired strength with a small amount of material, and further reduce the weight of the resin shock absorbing member of the present invention. It is because it can plan.
Hereinafter, such a fiber reinforced thermoplastic resin composite material will be described in detail.

(A) Reinforcing fibers (types of reinforcing fibers)
The type of the reinforcing fiber used in the fiber reinforced thermoplastic resin composite material can be appropriately selected according to the type of the thermoplastic resin and the degree of the shock absorbing property imparted to the shock absorbing portion, and is particularly limited. It is not a thing. For this reason, as the reinforcing fiber used in the present invention, any of inorganic fibers and organic fibers can be preferably used.

  Examples of the inorganic fibers include carbon fibers, activated carbon fibers, graphite fibers, glass fibers, tungsten carbide fibers, silicon carbide fibers (silicon carbide fibers), ceramic fibers, alumina fibers, natural fibers, mineral fibers such as basalt, and boron fibers. , Boron nitride fiber, boron carbide fiber, and metal fiber. Examples of the metal fiber include aluminum fiber, copper fiber, brass fiber, stainless steel fiber, and steel fiber. As said glass fiber, what consists of E glass, C glass, S glass, D glass, T glass, quartz glass fiber, borosilicate glass fiber, etc. can be mentioned. Examples of the organic fibers include fibers made of resin materials such as polybenzazole, aramid, PBO (polyparaphenylene benzoxazole), polyphenylene sulfide, polyester, acrylic, polyamide, polyolefin, polyvinyl alcohol, and polyarylate. it can.

  In the present invention, two or more kinds of reinforcing fibers may be used in combination. In this case, a plurality of types of inorganic fibers may be used in combination, a plurality of types of organic fibers may be used in combination, or inorganic fibers and organic fibers may be used in combination. As an aspect which uses multiple types of inorganic fiber together, the aspect which uses together a carbon fiber and a metal fiber, the aspect which uses a carbon fiber and glass fiber together, etc. can be mentioned, for example. On the other hand, examples of the mode in which a plurality of types of organic fibers are used in combination include a mode in which aramid fibers and fibers made of other organic materials are used in combination. Furthermore, as an aspect using together an inorganic fiber and an organic fiber, the aspect which uses together a carbon fiber and an aramid fiber can be mentioned, for example.

  The reinforcing fiber used in the present invention is preferably at least one selected from the group consisting of carbon fiber, glass fiber, metal fiber, ceramic fiber, polybenzazole fiber and aramid fiber, and in particular, carbon fiber. Is preferred. By using carbon fiber, light weight and high strength and rigidity can be secured. For example, when the resin impact absorbing member of the present invention is applied to an automobile, there is an advantage that fuel efficiency can be improved and driving performance can be improved. is there.

The carbon fibers are generally polyacrylonitrile (PAN) based carbon fibers, petroleum / coal pitch based carbon fibers, rayon based carbon fibers, cellulosic carbon fibers, lignin based carbon fibers, phenol based carbon fibers, and vapor growth systems. Although carbon fiber etc. are known, in the present invention, any of these carbon fibers can be suitably used.
The reinforcing fiber used in the present invention may have a sizing agent attached to the surface. When using the reinforcing fiber to which the sizing agent is attached, the type of the sizing agent can be appropriately selected according to the types of the reinforcing fiber and the thermoplastic resin, and is not particularly limited.

(Fiber length of reinforcing fiber)
The fiber length of the reinforcing fiber used in the present invention can be appropriately determined so that a desired compressive strength can be imparted to the thermoplastic resin base material according to the type of the reinforcing fiber, the type of the thermoplastic resin, or the like. It is not particularly limited. Therefore, in the present invention, continuous fibers may be used or discontinuous fibers may be used depending on the purpose. When using discontinuous fibers, the average fiber length is usually preferably in the range of 1 mm to 100 mm, more preferably in the range of 5 mm to 75 mm, and further in the range of 10 mm to 50 mm. It is particularly preferred.

In the present invention, when discontinuous fibers are used as the reinforcing fibers, reinforcing fibers having different fiber lengths may be used in combination. In other words, the reinforcing fiber used in the present invention may have a single peak in average fiber length, or may have a plurality of peaks. Here, the average fiber length (La) of the reinforcing fibers is measured, for example, by measuring the fiber length (Li) of 100 fibers randomly extracted from the fiber reinforced thermoplastic resin composite material to the 1 mm unit using calipers or the like. And can be obtained based on the following equation. Extraction of reinforcing fibers from the fiber-reinforced thermoplastic resin composite material is performed, for example, by subjecting the fiber-reinforced thermoplastic resin composite material to a heat treatment of about 500 ° C. for about 1 hour and removing the resin in a furnace. be able to.
La = ΣLi / 100

(Fiber diameter of reinforcing fiber)
The fiber diameter of the reinforcing fiber used in the present invention may be appropriately determined according to the type of the reinforcing fiber, and is not particularly limited. For example, when carbon fiber is used as the reinforcing fiber, the average fiber diameter is usually preferably in the range of 3 μm to 50 μm, more preferably in the range of 4 μm to 12 μm, and in the range of 5 μm to 8 μm. More preferably.
On the other hand, when glass fiber is used as the reinforcing fiber, the average fiber diameter is usually preferably in the range of 3 μm to 30 μm. Here, the said average fiber diameter shall point out the diameter of the single yarn of a reinforced fiber. Therefore, when the reinforcing fiber is in the form of a fiber bundle, it refers to the diameter of the reinforcing fiber (single yarn) constituting the fiber bundle, not the diameter of the fiber bundle. The average fiber diameter of the reinforcing fibers can be measured, for example, by the method described in JIS R-7607.

(Reinforcing fiber state)
Regardless of the type, the reinforcing fiber used in the present invention may be a single yarn consisting of a single yarn, or may be a fiber bundle consisting of a plurality of single yarns. In addition, the reinforcing fiber used in the present invention may be only a single yarn, may be a fiber bundle, or a mixture of both. When using fiber bundle-shaped reinforcing fibers, the number of single yarns constituting each fiber bundle may be uniform or different in each fiber bundle. When the reinforcing fibers used in the present invention are in the form of fiber bundles, the number of single yarns constituting each fiber bundle is not particularly limited, but is usually in the range of 1000 to 100,000.

  Generally, carbon fibers are in the form of fiber bundles in which thousands to tens of thousands of filaments are gathered. When carbon fibers are used as the reinforcing fibers, if the carbon fibers are used in the form of fiber bundles, the entangled portions of the fiber bundles are locally thick and it is difficult to obtain a thin fiber reinforced thermoplastic resin composite material. There is a case. For this reason, when using a carbon fiber as a reinforcing fiber, it is preferable to widen or open the fiber bundle.

When the carbon fiber bundle is opened and used, the opening degree of the carbon fiber bundle after opening is not particularly limited, but the opening degree of the fiber bundle is controlled, and the carbon fiber bundle consists of a specific number or more of carbon fibers. It is preferable to include a carbon fiber bundle and a carbon fiber (single yarn) or a carbon fiber bundle less than that. In this case, specifically, the carbon fiber bundle (A) constituted by the number of critical single yarns or more defined by the following formula (1) and the other opened carbon fibers, that is, the state of the single yarn or the criticality It is preferably composed of a fiber bundle composed of less than a single yarn.
Critical number of single yarns = 600 / D (1)
(Where D is the average fiber diameter (μm) of the carbon fiber)

  Furthermore, in the present invention, the ratio of the carbon fiber bundle (A) to the total amount of carbon fibers in the fiber-reinforced thermoplastic resin composite material is preferably more than 0 Vol% and less than 99 Vol%, and may be 20 Vol% or more and less than 99 Vol%. More preferably, it is 30 Vol% or more and less than 95 Vol%, More preferably, it is 50 Vol% or more and less than 90 Vol%. Thus, the carbon fiber in the fiber reinforced thermoplastic resin composite material can be obtained by coexisting a carbon fiber bundle composed of carbon fibers of a specific number or more and other opened carbon fibers or carbon fiber bundles in a specific ratio. This is because it is possible to increase the abundance, that is, the fiber volume content (Vf).

  The degree of opening of the carbon fiber can be set within a target range by adjusting the opening condition of the fiber bundle. For example, when the fiber bundle is opened by blowing air onto the fiber bundle, the degree of opening can be adjusted by controlling the pressure of the air blown onto the fiber bundle. In this case, by increasing the air pressure, the degree of opening is increased (the number of single yarns constituting each fiber bundle is small), and by reducing the air pressure, the degree of opening is reduced (constituting each fiber bundle). The number of single yarns to be increased).

When carbon fiber is used as the reinforcing fiber in the present invention, the average number of fibers (N) in the carbon fiber bundle (A) can be appropriately determined within a range not impairing the object of the present invention, and is particularly limited. It is not a thing.
In the case of carbon fiber, the N is usually within the range of 1 <N <12000, but more preferably satisfies the following formula (2).
0.6 × 10 ⁴ / D ² <N <6 × 10 ⁵ / D ² (2)
(Where D is the average fiber diameter (μm) of the carbon fiber)

(A) Thermoplastic resin As the thermoplastic resin used in the present invention, one or two or more types can be appropriately selected from those described above.

(C) Fiber reinforced thermoplastic resin composite material The presence state of the reinforced fiber in the fiber reinforced thermoplastic resin composite material is particularly limited as long as the compressive strength of the thermoplastic resin substrate can be within a desired range. Instead, it can be determined appropriately according to the fiber length of the reinforcing fiber. For example, when the reinforcing fiber is a discontinuous fiber, the presence state of the reinforcing fiber can be exemplified by random orientation, unidirectional orientation, or a combination thereof. Moreover, when a reinforced fiber is a continuous fiber, a unidirectional orientation or a textile form can be illustrated.

  The abundance of the thermoplastic resin in the fiber-reinforced thermoplastic resin composite material used in the present invention can be appropriately determined according to the type of the thermoplastic resin, the type of the reinforcing fiber, etc., and is particularly limited. Although it is not a thing, normally, it shall be in the range of 3 mass parts-1000 mass parts with respect to 100 mass parts of reinforced fiber.

Moreover, the volume content (Vf) of the reinforced fiber in the fiber reinforced thermoplastic resin composite material is
If it is in the range which can make the compressive strength of a thermoplastic resin base material into a desired grade, it will not specifically limit, According to the kind of reinforcement fiber, the average fiber length of a reinforcement fiber, etc., it can determine suitably. In particular, in the present invention, the lower limit of the volume content (Vf) of the reinforcing fibers is preferably 10% or more, more preferably 20% or more, and further preferably 30% or more. On the other hand, the upper limit of the volume content of the reinforcing fibers is preferably 70% or less, more preferably 60 or less, and even more preferably 50% or less. When the volume content (Vf) of the reinforcing fiber is within such a range, for example, when a plurality of thermoplastic resin base materials having different compressive strengths are bonded by press molding, the fiber reinforced heat is appropriately increased during pressing. This is because there is an advantage that the thermoplastic resin composite material can be flowed and it becomes easy to bond the thermoplastic resin base materials to each other.

  As described above, the fiber-reinforced thermoplastic resin composite material used in the present invention contains at least reinforcing fibers and a thermoplastic resin, but various additions are made as necessary as long as the object of the present invention is not impaired. An agent may be included. The various additives used in the present invention are particularly limited as long as they can impart a desired function or property to the fiber-reinforced thermoplastic resin composite material depending on the use of the fiber-reinforced thermoplastic resin composite material. It is not a thing. Examples of such various additives include, for example, melt viscosity reducing agents, antistatic agents, pigments, softeners, plasticizers, surfactants, conductive particles, fillers, carbon black, coupling agents, foaming agents, lubricants, Corrosion inhibitors, crystal nucleating agents, crystallization accelerators, mold release agents, stabilizers, UV absorbers, colorants, anti-coloring agents, antioxidants, flame retardants, flame retardant aids, anti-dripping agents, lubricants, fluorescence Examples include brighteners, phosphorescent pigments, fluorescent dyes, flow modifiers, inorganic and organic antibacterial agents, insecticides, photocatalytic antifouling agents, infrared absorbers, and photochromic agents.

C. Form of thermoplastic resin base material The thermoplastic resin base material used in the present invention may be composed of a single layer, or may be a laminate formed by being laminated in a plurality of layers. . As an aspect in which the thermoplastic resin substrate is a laminate, for example, an aspect in which a discontinuous fiber layer and a continuous fiber layer are laminated can be exemplified. Specific examples of such an embodiment include a sandwich laminate in which a discontinuous fiber layer is laminated in a core layer and a continuous fiber layer is laminated in a skin layer, or a sandwich in which a discontinuous fiber layer is laminated in a skin layer and a continuous fiber layer is laminated in a core layer. A laminate or a laminate obtained by laminating the continuous fiber layer while changing the angle for the purpose can be given. Another embodiment in which the thermoplastic resin base material is a laminate is a laminate in which discontinuous fiber layers having different compressive strengths are laminated. In particular, in the present invention, when the thermoplastic resin base material of the discontinuous fiber layer and the continuous fiber layer is used as a laminate, the discontinuous fiber layer is laminated on the skin layer, the continuous fiber layer is laminated on the core layer, and the lamination ratio is set to the thickness. A sandwich laminate that is symmetric in the direction is preferred. This is because warping of the thermoplastic resin substrate can be prevented. In addition, if the continuous fiber layer is used for the skin layer, the continuous fiber may be damaged at the time of impact absorption, and the performance as designed may not be obtained. This is because there are fewer concerns. Here, the “continuous fiber layer” refers to a thermoplastic resin base material containing continuous fibers as reinforcing fibers, and the “discontinuous fiber layer” refers to a thermoplastic resin containing discontinuous fibers as reinforcing fibers. Refers to the substrate.

D. A mode in which a plurality of thermoplastic resin base materials are used In the present invention, an impact-absorbing base material in which a plurality of thermoplastic resin base materials having different compressive strengths are combined is used. The difference in the compressive strength of the material is not particularly limited as long as it is within a range in which desired impact absorbing characteristics can be imparted to the resin impact absorbing member of the present invention. Especially in this invention, it is more preferable that the difference of the compressive strength of an adjacent thermoplastic resin base material exists in the range of 50 MPa-350 MPa, and it is further more preferable in the range of 100 MPa-250 MPa. When the difference in compressive strength between the adjacent thermoplastic resin base materials is within the above range, the impact is applied to the resin impact absorbing member of the present invention regardless of the magnitude of the impact or the direction of the impact. This is because it is possible to prevent the shock absorbing property from being damaged by the boundary of the thermoplastic resin base material being the starting point of destruction.

The aspect in which the compressive strength is different between the respective thermoplastic resin substrates is not particularly limited as long as it is an aspect other than the aspect in which the thickness is different. As such an aspect, when the thermoplastic resin base material is composed of only a thermoplastic resin, for example, an aspect in which the kind of the thermoplastic resin is different or an aspect in which the average molecular weight of the thermoplastic resin is different can be exemplified. . Further, when the thermoplastic resin base material is composed of the above-described fiber reinforced thermoplastic resin composite material, for example, a mode in which the types of the reinforcing fibers are different, a mode in which the average fiber length of the reinforcing fibers is different, a mode in which the orientation state of the reinforcing fibers is different The aspect etc. from which the volume content rate (Vf) of a reinforced fiber differs can be mentioned.
Moreover, the aspect etc. from which the laminated structure of a thermoplastic resin base material differs can be mentioned irrespective of the material which comprises a thermoplastic resin base material. As such an aspect, for example, an embodiment in which a thermoplastic resin base material composed of a single layer and a thermoplastic resin base material having a laminated structure are used in combination, or a thermoplastic resin base material having a laminated structure having a different structure is combined. Can be used.
Furthermore, the aspect which compounded each aspect mentioned above in this invention can also be used. Examples of such an embodiment include an embodiment in which the average fiber length of the reinforcing fibers and the volume content (Vf) of the reinforcing fibers are different, and an embodiment in which the types and laminated structures of the reinforcing fibers are different. is not.

In the case where the thermoplastic resin base material is composed of the above-described fiber-reinforced thermoplastic resin composite material, for example, the orientation state of the reinforcing fibers is different. For example, the thermoplastic resin base material in which the reinforcing fibers are randomly oriented and the reinforcing fiber are Examples include a mode in which a thermoplastic resin base material oriented in one direction is assembled, and a mode in which thermoplastic resin base materials having different degrees of orientation isotropic (anisotropy) are combined. Here, as the latter aspect, for example, an aspect in which thermoplastic resin base materials having different tensile elastic modulus ratios (Eδ) are combined can be exemplified. The tensile modulus ratio (Eδ) is determined by performing a tensile test based on an arbitrary direction of the thermoplastic resin substrate and a direction orthogonal thereto, and measuring the tensile modulus. The ratio (Eδ) obtained by dividing the larger value by the smaller value.
In addition, the aspect in which the volume content (Vf) of the reinforcing fibers is different is not particularly limited as long as it is within a range in which a desired degree of difference is provided in the compressive strength of the adjacent thermoplastic resin base material. Is preferably 10% or more, more preferably in the range of 5% to 60%, and more preferably in the range of 10% to 40%. preferable.
Furthermore, the aspect in which the average fiber length of the reinforcing fibers is different is not particularly limited as long as it is within a range in which a desired degree of difference can be provided in the compressive strength of the adjacent thermoplastic resin base material. The difference between the average fiber lengths of the reinforcing fibers in the adjacent thermoplastic resin base materials is preferably in the range of 5 mm to 90 mm, and more preferably in the range of 10 mm to 50 mm.

(3) Shock absorption part The shock absorption part in this invention consists of the said shock-absorbing base material. The shape of the impact absorbing portion in the present invention is not particularly limited as long as it can achieve a desired impact absorbing characteristic according to the use of the resin impact absorbing member of the present invention. For this reason, as a shape of the impact-absorbing part in this invention, the plate shape which consists of an impact-absorbing base material may be sufficient, for example, and the cylinder shape which has a hollow structure may be sufficient.

The shapes of these shock absorbing parts will be described with reference to the drawings. FIG. 5 is a schematic view showing an example in which the impact absorbing portion in the present invention has the plate shape. As illustrated in FIGS. 5A, 5 </ b> B, and 5 </ b> C, the impact absorbing portion 12 in the present invention may be a plate made of the impact absorbing base material 11. 5A, 5B, and 5C, the shock-absorbing base material 11 is made of thermoplastic resin base materials 11a and 11b having different compressive strengths.
Here, as an aspect in which the impact absorbing portion is plate-shaped, an aspect in which the impact-absorbing base material is bent as illustrated in FIGS. 5A and 5B may be used. As illustrated in c), the impact-absorbing base material may be bent into a curved surface. Furthermore, although illustration in a drawing is abbreviate | omitted, the flat form in which the shock-absorbing base material is not bent or bent may be sufficient.
FIG. 6 is a schematic view showing an example in which the impact absorbing portion in the present invention is the above-described cylindrical shape. As illustrated in FIGS. 6A and 6B, the impact absorbing portion 12 in the present invention may be cylindrical. In this case, as illustrated in FIGS. 6A and 6B, the wall portion of the cylindrical impact absorbing portion 11 is made of the thermoplastic resin base materials 11a and 11b.

  When the shock absorbing portion used in the present invention is cylindrical, the cross-sectional shape in the direction orthogonal to the shock absorbing direction of the shock absorbing portion is not particularly limited, and for example, a circle, an ellipse, a triangle Any shape of a polygon such as a rectangle may be used. As an example in which the cross-sectional shape is circular, for example, the embodiment illustrated in FIG. Moreover, as an example in which the cross-sectional shape is a polygon, for example, the mode illustrated in FIG.

Further, the aspect in which the impact absorbing portion used in the present invention is cylindrical may be an aspect composed of a single cylindrical body, or may be an aspect in which a plurality of cylindrical bodies are connected. Good. The case where the impact absorbing portion in the present invention is an aspect in which a plurality of cylindrical bodies are connected will be described with reference to the drawings. FIG. 7 is a schematic view showing an example of such an embodiment. As shown in FIGS. 7A and 7B, the impact absorbing portion used in the present invention may have a configuration in which a plurality of circular cylindrical bodies are connected, or a polygonal cylindrical body may be used. A plurality of connected modes may be used.
In addition, as an aspect formed by connecting a plurality of cylindrical bodies, the impact absorbing portion used in the present invention may be an aspect in which individually formed cylindrical bodies are connected afterwards (for example, FIG. 7 (a)), or a mode in which a plurality of cylindrical bodies are connected by, for example, combining a plurality of parts having concave portions (for example, FIG. 7B).

  The shape of the impact absorbing portion in the present invention can be suitably used regardless of the plate shape or the cylindrical shape, but the cylindrical shape is preferable. Due to the cylindrical shape of the shock absorbing portion, breakage at the time of shock absorption occurs in all parts over the entire circumference of the shock absorbing portion, and continuous stable breakage can be sustained to absorb a large shock. Therefore, the impact absorption efficiency per member weight of the resin impact absorbing member of the present invention can be improved. In addition, the cylindrical shape can improve the rigidity of the shock absorbing portion more than the plate shape, and can prevent a difference in shock absorption characteristics depending on the angle at which the shock is input. .

2 Resin Shock Absorbing Member The resin impact absorbing member of the present invention includes at least the impact absorbing portion, but may have other configurations as necessary. Other configurations used in the present invention include, for example, a bottom formed so as to be connected to the rear end with respect to the shock absorbing direction of the shock absorbing portion, and a lid formed so as to be connected to the front end. In order to ensure the shape rigidity of the resin shock absorbing member, a plate-like insertion member can be used.
FIG. 8 is a schematic view showing an example in which a bottom and a lid are used as the other configuration. As illustrated in FIG. 8, the shock absorbing portion 10 of the present invention may have a bottom portion 13 formed so as to be connected to the rear end portion with respect to the shock absorbing direction of the shock absorbing portion 12. Furthermore, you may have the cover part 14 formed so that it might be connected to a front-end | tip part.

3. Method for Producing Resin Impact Absorbing Member The resin impact absorbing member of the present invention can be produced, for example, by the following method. That is, first, two types of thermoplastic resin base materials having different compressive strengths, in which a thermoplastic resin and a reinforcing fiber are integrated in advance, are prepared, and the two types of thermoplastic resin base materials are preliminarily designed in a mold. The two thermoplastic resin substrates are bonded simultaneously with the press molding. The molded article of the shock-absorbing base material thus obtained is fastened by vibration welding so that the concave portions face each other to form a closed cross section, thereby forming a resin shock-absorbing member having a cylindrical shock-absorbing portion. . In addition to the vibration welding, it is also possible to use ultrasonic welding, adhesion, rivets, bolts and nuts, etc. as the fastening method of the molded product.

4. Use of Resin Impact Absorbing Member The resin impact absorbing member of the present invention can be used as, for example, an impact absorber that is incorporated in a vehicle skeleton structure and absorbs and reduces the impact at the time of a vehicle collision. In particular, it can be used for a vehicle body structure such as a support member inside a bumper equipped in an automobile, a shock absorbing member installed inside a pillar or a side sill, a side member, or a cross member.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the technical idea described in the claims of the present invention has substantially the same configuration and exhibits the same function and effect regardless of the mode. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described more specifically by showing examples and comparative examples.

[Example]
Carbon fiber “Tenax (registered trademark)” STS40-24KS (average fiber diameter 7 μm) manufactured by Toho Tenax Co., Ltd. cut to an average fiber length of 20 mm was used as the reinforcing fiber, and nylon 6 resin manufactured by Unitika Co., Ltd. was used as the thermoplastic resin. Using A1030 (breaking elongation 50%), carbon fibers are two-dimensionally randomly oriented in the in-plane direction, and mixed so that the fiber volume content relative to the entire fiber reinforced resin material is 20 Vol% and 35 Vol%. In a press apparatus heated to 280 ° C., heat-compressed with a pressure of 2.0 MPa for 5 minutes, the thermoplastic fiber base material A having an average fiber length of about 20 mm and a fiber volume content of about 20 Vol% and heat of 35 Vol% A plastic resin substrate B was prepared. As a result of measuring the compressive strength of the thermoplastic resin substrates A and B, they were 150 MPa and 300 MPa, respectively.

After heating the obtained thermoplastic resin base materials A and B to 280 ° C., the end portions of the thermoplastic resin base materials A and B are partially overlapped, and cold press molding is performed, and the rear side from the tip side that receives an impact A shock-absorbing group in which the compressive strength increases toward the end side, the thermoplastic resin base materials A and B are bonded in this order, and the ratio of the lengths of the two thermoplastic resin base materials A and B is 1: 4. A molded product of the material was obtained. At this time, the average thickness of the thermoplastic resin substrate A was 1.6 mm, and the average thickness of the thermoplastic resin substrate B was 1.6 mm. Moreover, the thermoplastic resin base materials A and B were bonded so that the existence ratio in the thickness direction continuously changed at the boundary. The shape of the molded product was as shown in FIG. 9A, and the dimensions of each part were a = 50 mm, b = 100 mm, c = 12 mm, d = 80 degrees, and e = 150 mm. Next, the flange portion of the shock-absorbing base material was vibration welded to produce a resin shock-absorbing member comprising a hexagonal shock-absorbing portion as shown in FIG.
The resin shock absorbing member produced as described above was set in a falling rock impact tester so that the shock absorbing direction was vertical, and a compressive load of 500 J was applied in the same direction as the shock absorbing direction. The load was 34.4 kN, and the displacement required for shock absorption was 39.4 mm.

[Comparative Example 1]
The fiber reinforced resin material B of Example 1 was heated to 280 ° C. and subjected to cold press molding to obtain a molded article of an impact-absorbing base material. Subsequently, the flange part of the molded article of the said shock-absorbing base material was vibration welded, and the resin-made impact-absorbing member which consists of a hexagonal-type impact-absorbing part of the same shape as Example 1 was produced. The prepared resin shock absorbing member was set on a falling-drop impact tester so that the shock absorbing direction was vertical, and a compressive load of 500 J was applied in the same direction as the shock absorbing direction. The initial shock load was 48.6 kN. The displacement required for impact absorption was 63.0 mm.

[Comparative Example 2]
A5052 (aluminum) consisting of a hexagonal shock absorbing portion having the same shape as in Example 1 and a uniform outer cylinder thickness of 1.5 mm is formed by press-forming A5052 (aluminum) and spot welding the flange portion. An impact-absorbing member made was produced. The prepared aluminum shock absorbing member was set in a falling rock impact tester so that the shock absorbing direction was vertical, and a compressive load of 500 J was applied in the same direction as the shock absorbing direction, and the initial shock load was 108.3 kN. The displacement required for shock absorption was 10.9 mm.

[Reference example]
The fiber reinforced resin material B of Example 1 is heated to 280 ° C., and the thickness of the shock-absorbing base material is 1.3 mm and 1.6 mm from the front end side receiving the impact to the rear end side in advance, and the front end receiving the impact The molded product of the impact-absorbing base material was obtained by putting into a mold designed to have a length ratio of 1: 4 from the side toward the rear end side and cold press molding. Subsequently, the flange part of the molded article of the said shock-absorbing base material was vibration welded, and the resin-made impact-absorbing member which consists of a hexagonal-type impact-absorbing part of the same shape as Example 1 was produced. The prepared resin shock absorbing member was set in a drop impact tester so that the shock absorbing direction was vertical, and a compressive load of 500 J was applied in the same direction as the shock absorbing direction. The initial shock load was 35.9 kN. The displacement required for shock absorption was 38.5 mm.

  From the results of the above examples and comparative examples, the resin impact absorbing member of the present invention has an initial impact as compared with the resin impact absorbing member using the impact absorbing substrate made of a single thermoplastic resin substrate. It was confirmed and verified that the load can be kept low and the displacement required for shock absorption can be kept low. In addition, the resin shock absorbing member of the present invention can obtain almost the same performance as a resin shock absorbing member (reference example) having a change in thickness in order to change the compressive strength. The resin impact absorbing member of the present invention had a weight of about one half compared to the impact absorbing member of Comparative Example 2 made of A5052 (aluminum). The impact absorbing member of Comparative Example 2 has a small maximum displacement, but the entire specimen was buckled and deformed. On the other hand, the resin impact absorbing member of the present invention has a fracture that occurs at the tip and spreads to the adjacent portion. Since it becomes possible to absorb impact by progressively breaking in the direction, it is possible to effectively use the full length of the resin shock absorbing member as much as the overlap of thermoplastic resin base materials does not occur. It was found that can be shortened.

  The resin impact absorbing member of the present invention can be used for an energy absorbing device such as a vehicle.

DESCRIPTION OF SYMBOLS 10 Resin-made impact-absorbing member 11 Shock-absorbing base material 11a, 11b, 11c Thermoplastic resin base material 12 Shock-absorbing part 13 Bottom part 14 Cover part

Claims (6)

A resin shock absorbing member having a shock absorbing portion composed of a shock absorbing base material having a substantially constant thickness,
The impact-absorbing base material is a resin-made impact-absorbing member comprising a plurality of thermoplastic resin base materials having different compressive strengths in the direction of impact absorption.   2. The shock absorbing base material according to claim 1, wherein the plurality of thermoplastic resin base materials are arranged in order of increasing compressive strength from a front end side to a rear end side where the impact is received. Resin shock absorbing member.   The resin-made impact absorbing member according to claim 1 or 2, wherein the plurality of thermoplastic resin base materials are made of a fiber-reinforced thermoplastic resin composite material containing reinforcing fibers and a thermoplastic resin. .   The resin-made impact absorbing member according to claim 3, wherein the plurality of thermoplastic resin base materials have different compressive strengths due to different volume contents of the reinforcing fibers.   The shock-absorbing base material is bonded so that adjacent thermoplastic resin base materials continuously change in the thickness direction at the boundary thereof. The resin shock absorbing member according to any one of the above.   The resin impact absorbing member according to any one of claims 1 to 5, wherein the impact absorbing portion has a cylindrical shape having a hollow structure.

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