JPH1113806A - Shock energy absorbing member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock energy absorbing member having an excellent characteristic, which can be manufactured by a simple process. SOLUTION: In a shock energy absorbing member having a hollow cylindrical unit manufactured by injection molding of a thermoplastic resin, at least one of an orientation direction in inner/outer sides is different from an axial direction of the cylindrical unit. As the thermoplastic resin, a compound containing an aromatic ring included as a constitutional monomer, monomer contained in a main chain, thermotropic liquid crystal polymer, containing a fiber charging agent, etc., can be used. In the orientation direction, for instance, an orientation direction in one side of inner/outer side of the hollow cylindrical unit is 10 deg. or more relating to a center axis of the hollow cylindrical unit, and an orientation direction in the other side is almost parallel relating to the center axis of the hollow cylindrical unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION [0002] Transportation means in which the load is human, animal, dangerous goods, etc., is subjected to an unexpected impact.
A shock absorbing structural member for absorbing the shock energy is provided. The present invention relates to this shock absorbing structural member, and more particularly to a shock energy absorbing member obtained by injection molding of a thermoplastic resin, which irreversibly absorbs this energy in its own specific failure mode.

[0002]

2. Description of the Related Art An aircraft, a helicopter or an elevator breaks down as a shock absorber (for example, a bumper support member) for damping an impact of a moving body such as a vehicle or a ship colliding with a stationary body such as a quay or a pier. As a shock absorber for buffering the impact when landing at the ground, or as a shock absorber for buffering the impact when a nuclear fuel transportation device (cask) or a container containing radioactive waste (canister) falls. An impact energy absorbing member that reversibly absorbs impact energy is provided.

Conventionally, as these shock absorbing structural members, those using a liquid buffer mechanism utilizing the principle of converting and consuming shock energy into friction energy and then into heat energy, and "impact energy is subjected to plastic deformation of metal" Using a specific shape structure such as a tubular or honeycomb shape made of a specific strength metal material utilizing the principle of conversion and consumption into
Etc. are used.

However, these shock absorbing structural members have excellent characteristics as shock absorbing structural members themselves, but (1) have a complicated structure and are liable to break down (mechanical, corrosion, etc.) (2) high manufacturing costs ( (3) There are problems such as heavy (use of metal structural materials, etc.), and improvement in these points is desired.

[0005] In recent years, with respect to shock absorbing structural members mounted on vehicles, aircraft, elevators, and the like, there is an increasing demand for space saving and weight reduction with the trend toward lighter weight and higher functionality of these transporters. In order to respond to this demand, impact energy absorbing members with a high impact energy absorption per unit volume or impact energy absorbing members with a high impact energy absorption per unit weight have been studied from both material and structural aspects. I have.

[0006] Further, the cost of these transporters is strongly reduced, and from this aspect, studies are being made on both the materials and the structure. With these studies, the above-mentioned disadvantages of the conventional impact energy absorbing member have been recognized as an extremely large problem than ever before.

[0007] In order to overcome this problem, the development of impact energy absorbing members made of a fiber composite synthetic resin has been increasingly carried out, with particular emphasis on the development of impact energy absorbing members mounted on vehicles.

For example, Japanese Patent Application Laid-Open No. 57-12412 proposes a hollow structure having a clothing surface having a network structure composed of strips made of a fiber composite material. As an example of a strip, a No. 800 glass fiber roving impregnated with an epoxy resin is shown. However, although this method solves the above problems (1) and (3), the production is complicated, and further improvement of the above improvement (2) is desired. In addition, the adjustment related to various property requirements largely depends on the winding angle of the strip around the structure and the relative angle between the strips in addition to the material properties. There are problems with suitability for manufacturing structural members. Composite Science and Technology,
24 (1985), p. 275-298), suggests a possibility as a shock-absorbing structural member made of a fiber composite synthetic resin, but does not suggest an effective structure.

Japanese Patent Application Laid-Open No. Hei 5-118370 proposes a hollow structure containing fibers inclined at 0 to 45 ° with respect to the hollow body axis, and having both or one of the tip portions chamfered. I have. However, even with this method, although the problems of the above-mentioned improvements (1) and (3) have been solved, the production is complicated by using a prepreg or using a special mold, and the above-mentioned improvement (2) is not considered. Further improvement is desired. Further, the adjustment relating to various property requirements largely depends on the prepreg properties in addition to the material properties. Considering the complexity of the manufacturing method, there is a problem in suitability for manufacturing various shock absorbing structural members. JP-A-6-264949 proposes a short fiber reinforced hollow structure in which the thickness gradually increases from a first end to a second end, and the first end is curved outward. This method solves the above problems (1) and (3) by making the reinforcing fibers short fibers, and also makes it possible to manufacture by ordinary injection molding.
Problem (2) has been solved. However, since the impact energy absorption of the resin-made impact-absorbing structural member largely depends on the relationship between the orientation angle of the filled reinforcing fiber and the applied impact, this method, in which the orientation control is not sufficient, requires that the impact energy absorption per unit volume be different. It is smaller than the resin shock absorbing structural member. Therefore, in addition to the installation of the thick part, the installation of the reinforcement part, a complicated change in the thickness structure, and the like are required, and eventually, the structure becomes complicated and the weight of the product increases.

Japanese Unexamined Patent Publication No. Hei 6-300688 proposes a fiber-reinforced hollow structure having a plurality of structures having different elastic moduli from the reinforcing fibers, but solves the above problems (1) and (3). However, the prepreg is complicated and the above improvements
As for (2), the complexity of the structure and the manufacturing method is further increasing, and further improvement is desired. In addition, adjustments for various characteristic requirements largely depend on prepreg characteristics in addition to material characteristics, and considering the complexity of the manufacturing method,
There is a problem in compatibility with the manufacture of various shock absorbing structural members.

[0011]

The impact energy absorbing member made of a synthetic resin has been studied with a prepreg (long fiber) / thermosetting resin. It is evaluated by the characteristic curve of the generated stress.

At this time, the relative angle between the orientation direction of the prepreg fibers contained in the hollow cylindrical body and the axis of the hollow cylindrical body (the direction coincides with the direction in which the compressive load is applied) greatly affects this characteristic. Has been confirmed to give. Composite Science and Technology
According to e Science and Technology, 24 (1985) p. 275-298), an example showing the best value when this angle is 90 ° is given. This is because although the impact energy absorption of the prepreg (long fiber) / thermosetting resin-based material is complicated, the best value can be obtained by maximizing the impact energy absorption due to fiber breakage in the impact energy absorption. Can be interpreted. In addition, this is because the prepreg (long fiber) / thermosetting resin can provide an excellent hollow cylindrical impact energy absorbing member because of a factor that greatly affects the impact energy absorption, that is, the filler fiber. It shows that the orientation depends on being arbitrarily controllable. However, as described above, this proper orientation control is possible only through a complicated process.

A thermoplastic resin or a short fiber / thermoplastic resin whose orientation is controlled also exhibits a large impact energy absorbing property with respect to impact energy applied from a direction whose orientation is controlled and a direction of 90 °. It is known. This can be confirmed from the fact that even in a normal injection-molded article, a portion called a skin layer, which is oriented to the strength of the molded article, exhibits excellent properties against impact energy applied from a direction of 90 °. Also, the orientation at this time, both the orientation of the thermoplastic resin molecules themselves and the orientation of the filler, and,
It refers to the synergistic effect, and is significantly different from thermosetting resin in that the orientation of the resin molecules themselves occurs.

However, when a hollow cylindrical body is injection-molded with these thermoplastic resin materials, the resin molecules injected from the gate or the orientation of the filler satisfy the conditions of high-speed filling and rapid solidification. Except for parts, it shows only a very weak orientation. In particular, the orientation is extremely weak inside a molded product called a core portion.

Therefore, despite the fact that the thermoplastic resin is extremely excellent in moldability, when the impact energy absorbing member of a hollow cylindrical body is molded by a usual injection molding method, a factor that greatly contributes to the impact energy absorption, that is, , The orientation of the resin molecules, and the orientation of the filler is small,
There is no method that can arbitrarily control the orientation. This is considered to be the reason why it is impossible to manufacture an excellent impact energy absorbing member made of a hollow cylindrical body made of a thermoplastic resin material.

[0016]

SUMMARY OF THE INVENTION The present invention has solved the problems relating to a shock energy absorbing member made of a thermosetting resin while maintaining the superiority of a synthetic resin shock absorbing structural member over a conventional shock energy absorbing member. The present invention relates to an impact energy absorbing member made of a thermoplastic resin.

That is, a first aspect of the present invention is that a hollow cylindrical body produced by injection molding of a thermoplastic resin, characterized in that at least one of the orientation directions inside and outside is different from the axial direction of the cylindrical body. And a shock energy absorbing member comprising:

According to a second aspect of the present invention, in the first aspect of the present invention, the thermoplastic resin contains a compound containing an aromatic ring as a main constituent monomer, and the monomer is contained in a main chain. And an impact energy absorbing member.

A third aspect of the present invention is the first or second aspect of the present invention.
, Wherein the plastic resin is a liquid crystal polymer.

A fourth aspect of the present invention relates to the impact energy absorbing member according to any one of the first to third aspects of the present invention, wherein the thermoplastic resin contains a fiber filler.

According to a fifth aspect of the present invention, in the first to fifth aspects of the present invention, the orientation direction of one of the inner side and the outer side of the hollow cylindrical body is 10 ° or more with respect to the center axis of the hollow cylindrical body. The present invention relates to an impact energy absorbing member, wherein the orientation direction on the other side is substantially parallel to the central axis of the hollow cylindrical body.

According to a sixth aspect of the present invention, in the first aspect of the present invention,
The present invention relates to an impact energy absorbing member, wherein the thermoplastic resin is a thermotropic liquid crystal polymer.

The hollow cylindrical body as the impact energy absorbing member of the present invention is used in a state where the hollow cylindrical body is attached so that a compressive strain is generated from the axial direction of the cylindrical portion.

That is, the impact energy absorber of the present invention comprises a cylindrical body produced by injection molding a thermoplastic resin, and either the orientation inside the cylinder or the orientation outside the cylinder is the same as that of the cylindrical body. By being different from the axial direction, when the cylindrical body is irreversibly destroyed by receiving a compressive load from the axial direction of the cylinder, smooth and continuous crushing is ensured. Only the outer or inner orientation may be different from the axial direction, and the other side orientation may be the same as the axial direction.
The outer orientation and the inner orientation are in the same direction, but may be different from the axial direction. In any case, any one of the inner orientation and the outer orientation may be different from the axial direction of the cylindrical body.

An aromatic member containing a compound containing an aromatic ring as a main constituent monomer and a thermoplastic resin containing the monomer in the main chain has high orientation and therefore high absorption strength and high absorption energy. can do. Further, this is more highly achieved by employing a thermotropic liquid crystal polymer as a thermoplastic resin as a material of the member of the present invention.

If a fiber filler is added to the thermoplastic resin, the strength becomes higher and the level of absorbed energy becomes higher.

In order to obtain a structure in which the orientation directions of the inner surface and the outer surface are different from each other, specifically, the orientation direction of one of the inner side and the outer side of the cylindrical body is set with respect to the center axis of the hollow cylindrical body. It is preferable that the angle is 10 ° or more, and the orientation direction on the other side is substantially parallel to the central axis of the hollow cylindrical body. Hereinafter, the present invention will be described in detail.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The impact energy absorbing member of the present invention has a hollow cylindrical structure whose both ends are open, so that it can absorb irreversible impact energy against a compressive load applied in the axial direction of the cylinder. Can be performed effectively. Therefore, it is the most effective form as such a member for absorbing impact energy. Further, a shape partially deformed by a known deformation method in order to increase the absorption of impact energy while maintaining a hollow cylindrical structure having both open ends is also within the scope of the present invention. That is, for example, 1) attaching a bottom plate to one end of a cylinder,
2) A continuous or discontinuous arbitrary thickness change is applied to the thickness of the cylinder. 3) The areas of the openings at both ends of the cylinder are made different from each other (that is, in this case, the cross-sectional shape along the axis is changed). Becomes a trapezoidal shape and becomes a hollow frustoconical body),
4) Design changes, such as increasing the impact energy absorption known in the art, such as installing ribs in the circumferential direction, are possible. In the present invention, since a thermoplastic resin is used as a main material, these arbitrary design changes can be made freely. It is also possible to easily provide a known trigger shape at the end.

The impact energy absorbing member of the present invention is made of a thermoplastic resin. These thermoplastic resins can be formed into hollow cylindrical bodies having different orientation directions between the inside and the outside by injection molding, and serve as an impact energy absorbing member excellent in impact energy applied from a specific direction.

Therefore, if a thermoplastic resin having a molecular structure in which a high elastic modulus appears by orientation is used, an extremely large effect can be exhibited, and it is preferable as a material of the impact energy absorbing member of the present invention. For this reason, a typical thermoplastic resin as a preferable resin includes a compound containing an aromatic ring as a main constituent monomer, the monomer is contained in a main chain, and has a rigid molecular structure. Specific examples of the monomer compound containing an aromatic ring as such a main constituent monomer include bisphenol A, metaxylylenediamine, terephthalic acid, 2,
Monomers such as 6-naphthalenedicarboxylic acid and dihydric phenol are exemplified.

The compound containing an aromatic ring is contained as a main constituent monomer, and the monomer is contained in a main chain;
Resins having a rigid molecular structure can be easily obtained from commercially available resins. For example, a polyamide containing metaxylylenediamine as a main constituent monomer (for example, MXD nylon resin (trade name) manufactured by Mitsubishi Gas Chemical Company); a polyester containing terephthalic acid as a main constituent monomer (for example, polyethylene terephthalate resin) Polyester containing 2,6-naphthalenedicarboxylic acid as a main constituent monomer (for example, PEN resin); polycarbonate and polyester containing bisphenol A as a main constituent monomer; polyphenylene sulfide; polyphenylene oxide; Polysulfone; 2
Polyarylate containing polyhydric phenol as a main constituent monomer (for example, U-polymer resin (trade name) manufactured by Unitika)
Polyether ketone; polyether ether ketone; p-hydroxybenzoic acid, hydroxynaphthoic acid,
Thermotropic liquid crystal polymers exhibiting optical anisotropy when melted using dihydric phenol or biphenol as a main constituent monomer (for example, Sumika Super (trade name) manufactured by Sumitomo Chemical Co., Zyder (trade name) manufactured by Amoco, DuPont) Xenite (trade name), Hoechst-Celanese Corporation, Vectra (trade name), Toray Siberus (trade name), Unitika Rod Run (trade name), and the like.

Among these, thermotropic liquid crystal polymers have an extremely rigid molecular structure, exhibit an effect called self-reinforcement by being aligned, and have an extremely large elastic modulus in the alignment direction. Is preferable.

The thermoplastic resin may be used alone or in a mixture of a plurality. It is effective to add a fiber filler to the thermoplastic resin for the purpose of increasing the elastic modulus in the orientation direction during orientation. For example, glass fiber,
Examples thereof include carbon fiber, aromatic polyamide fiber (for example, Kevlar (trade name) manufactured by DuPont), silicon carbide fiber, boron fiber, and phenol resin fiber (for example, Kainol (trade name) manufactured by Gunei Chemical Co., Ltd.).

The impact energy absorber of the present invention comprises a cylindrical body produced by injection-molding the above-mentioned thermoplastic resin, and one of the orientation inside the cylinder and the orientation outside the cylinder is the same as that of the cylinder. By being different from the axial direction, when the cylindrical body is irreversibly destroyed by receiving a compressive load from the axial direction of the cylinder, smooth and continuous crushing is ensured. Note that only the outer or inner orientation is different from the axial direction, and the other side orientation can be the same as the axial direction. The outer orientation and the inner orientation are in the same direction, but may be different from the axial direction. In any case, any one of the inner orientation and the outer orientation may be different from the axial direction of the cylindrical body. The preferred orientation of the hollow cylindrical body of the present invention is such that the orientation directions are different between the inside and the outside.

It is preferable that the orientation of any one of the thermoplastic resin on the inner surface and the outer surface of the hollow cylindrical body is different from the center axis of the hollow cylindrical body by 10 ° or more. Also,
When this angle is set to 30 ° or more, an impact energy absorbing member having better characteristics can be obtained. Upper limit is 90 °
However, those oriented to this extent are difficult to manufacture,
Usually it is up to 80 °. In addition, as the state of orientation,
The orientation of the inner surface of the hollow cylinder is axial, and the orientation of the outer surface can be inclined by 10 ° or more with respect to it, and conversely, the orientation of the outer surface of the hollow cylinder is axial. And the orientation of the inner surface is 10
It can be tilted more than °. Either embodiment can be used.

The difference between the inside and outside orientations of the hollow cylindrical body can be confirmed by various measuring methods. For example, the hollow cylindrical body can be cut into slices, and the orientation can be measured and confirmed over the thickness direction by X-ray diffraction according to a conventional method. In addition, simply, the flow state on each surface inside and outside the hollow cylindrical body,
For example, it can be confirmed by observing the flow mark and observing the direction of each flow. Depending on the coloring state of the resin, it may be difficult to observe the flow state of the surface. In such a case, for example, in the case of a black blend, the orientation direction on each surface can be confirmed by mixing a small amount of a white pellet in a resin pellet and observing the flow direction of the color.

The manufacturing method of the hollow cylindrical body in the impact energy absorber of the present invention is not particularly limited as long as the hollow cylindrical body has the above orientation. For example, the orientation of such a hollow cylindrical body is determined by filling a mold or a core portion constituting the inside or outside of the hollow cylindrical body of the mold while rotating the mold around a shaft, thereby filling the molten resin. Can be caused by entrainment caused by frictional resistance from the rotating wall.

More specifically, for example, in injection molding of a hollow cylindrical body composed of an outer mold and a rotating core, a gate is provided near the end of the hollow cylindrical body forming portion (cavity) in the mold. If the resin is injected while rotating the rotating core,
In the process in which the thermoplastic resin is flow-filled into the shaft method of the hollow cylindrical body, the molten resin flows in the same direction as the shaft due to the pressure applied from the injection molding machine, and between the rotating motion part of the rotating core and the molten resin. And the flow of the molten resin in the direction of 90 ° coexists due to the frictional resistance, and the actual molten resin is oriented in a direction in which these are balanced. If manufactured in this way,
The whole hollow cylindrical body is oriented in a direction different from the axial direction. Of course, the orientation also includes its surface state. Note that a method in which the core is stationary and injection molding is performed while rotating the outer mold is also effective. In addition, although both the rotating core and the outer mold are rotated, they can be manufactured by a method in which the rotating direction, speed, and the like are made different.

Usually, the orientation of the thermoplastic resin inside and outside the hollow cylindrical body is 10 ° with respect to the center axis of the hollow cylindrical body.
The rotational motion is applied so as to be controlled in different directions.
For this purpose, the number of rotations of the rotating part should be determined experimentally and empirically in relation to the shape of the hollow cylindrical body, the time required for filling, the desired orientation angle, the frictional resistance between the rotating part and the molten resin, etc. Is appropriate. This is due to the mold surface roughness, material properties,
This is because frictional resistance is greatly affected by molding conditions and the like. Normally, outer diameter 20mm, wall thickness 1mm, height 5c
m, the time required for filling is 1 second, and the desired orientation angle is 45 ° in the case of a hollow cylindrical body. When the rotating portion is the inner forming portion of the hollow cylindrical body, the standard of the number of rotations is 200 to 400 rpm.
m.

Next, one method of manufacturing the impact energy absorber of the present invention will be described with reference to FIG. 1 in the figure
Is an injection molding machine, 2 is a path of a molten polymer, 3 is a runner, 4 is a rotating core, 5 is an outer mold, and 6 is a forming section of a cylindrical body formed by the rotating core 4 and the outer mold 5 ( Cavity). 7 is a bearing for holding the rotation of the core, 8 is a chain for driving the core, 9 is a motor, and 10 is a protruding pin. The molten resin is injected from the injection molding machine 1 and is injected into the cavity 6 from the molten resin passage 2 and the runner 3. In the case of molding a cylindrical body having the above dimensions, the rotation speed of the rotating core portion is rotated in the range of 100 to 400 rpm, preferably 200 to 400 rpm. The molten resin injected into the cavity is rotated and rotated along with the wall by the rotation of the rotating core, and is oriented. If the bearing 7 is made of an elastic material, there is little risk of seizing during rotation of the core.

The thermotropic liquid crystal polyester resin is a thermotropic liquid crystal copolyester resin having repeating units each derived from phthalic acid / isophthalic acid / 4-hydroxybenzoic acid / 4,4-dihydroxydiphenyl, Each molar ratio is 0.75 /
0.25 / 3/1. When the optical anisotropy was observed using a polarizing microscope equipped with a hot stage, it showed optical anisotropy in a molten state at 340 ° C. or higher.

Using a composition containing 30% by weight (based on the whole composition) of glass fiber in this resin, an apparatus having an outer diameter of 20 mm, a wall thickness of 1 mm, a length of 150 mm, and a weight of 15 was obtained by the apparatus shown in FIG.
g was injection molded. The injection time was about 5 seconds and the cooling time was about 10 seconds, which required a total of about 15 seconds. Observing each of the outer surface and the inner surface of the obtained cylindrical body and confirming the direction of the resin flow from the flow mark, the direction of the resin flow on the outer surface substantially coincides with the axial direction of the cylindrical body. The direction of the resin flow on the inner surface was inclined about 33 ° with respect to the axial direction of the cylindrical body.

Here, for example, when the rotational torque is insufficient, the rotating member slips, and the entrainment of the peripheral molten resin may become insufficient. Further, the viscosity of the molten resin, which affects the rotational torque, greatly changes depending on the resin temperature, the mold temperature, and the heat generated by shearing during injection molding, and the frictional resistance in the molding process changes accordingly. For this reason, it is preferable that the rotation of the rotary core portion 4 be an optimal and stable frictional resistance force in each molding process in order to obtain an optimal orientation. In order to make the orientation stable and optimal as described above, for example, as disclosed in Japanese Patent No. 2537131, it is possible to detect the torque of the rotating part and control it to an arbitrary set value. is there. In this way, the frictional resistance between the rotating part and the molten resin is controlled, and as a result, stable and optimal orientation control can be performed.

As described above, the orientation in the hollow cylindrical body produced by the injection molding method in which the rotating core, the outer mold or both are rotated is the same as the axis caused by the pressure applied from the injection molding machine. The direction is determined by the balance between the flow of the molten resin in the direction and the flow of the molten resin in the 90 ° direction with respect to the axis caused by the frictional resistance between the rotary motion part and the molten resin. Therefore, if there is a difference in the rotational movement between the part forming the inside and the outside of the hollow cylindrical body of the mold (for example, when only the part forming the inside is rotated), the thickness of the hollow cylindrical body is increased. Since the balance between the two parts in the direction changes continuously, the orientation also changes continuously. As a result, the orientation of each part in the thickness direction is different. This orientation is a continuous orientation unique to the present invention, and since it is continuous, a smooth absorption of impact energy can be achieved. Such a smooth absorption is an absorption mode that is difficult to obtain by a conventional orientation combination of a laminated prepreg in a hollow cylindrical impact energy absorbing member made of a prepreg (long fiber) / thermosetting resin material.

Also, this feature is that the method of manufacturing the impact energy absorbing member of the hollow cylindrical body according to the present invention has various external impact energy absorption by controlling the rotational movement of the mold while having the same external dimensions. This shows that the method can manufacture a member.

The use form of the impact energy absorbing member according to the present invention is not limited. For example, it can be used alone or in combination of two or more, and may be used in combination with other impact energy absorbing members, structural members, and the like.

[0047]

According to the hollow cylindrical body of the present invention, either the outer surface or the inner surface of the hollow cylindrical body is oriented in a direction different from the axial direction of the cylindrical body. When the cylindrical body is irreversibly destroyed by receiving a compressive load from, smooth and continuous crushing is ensured, and as a result,
It is possible to absorb impact energy effectively and with high absorption levels. Further, the orientation of the hollow cylindrical body of the present invention is a continuous orientation, and since it is continuous, smooth absorption of impact energy can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram of a manufacturing apparatus for manufacturing an absorber made of a cylindrical body of the present invention by injection molding using a rotating core.

[Explanation of symbols]

1: injection molding machine, 2: molten polymer passage, 3: runner, 4: rotating core, 5: outer mold, 6: cylindrical body forming portion (cavity), 7: bearing, 8: chain, 9:
Motor 10, protruding pin.

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Claims (5)

[Claims] 1. An impact energy absorbing member having a hollow cylindrical body manufactured by injection molding of a thermoplastic resin, wherein at least one of the orientation directions inside and outside is different from the axial direction of the cylindrical body. . 2. The impact energy absorbing member according to claim 1, wherein the thermoplastic resin contains a compound containing an aromatic ring as a main constituent monomer, and the monomer is contained in a main chain. . 3. The impact energy absorbing member according to claim 1, wherein the thermoplastic resin is a thermotropic liquid crystal polymer. 4. The impact energy absorbing member according to claim 1, wherein the thermoplastic resin contains a fiber filler. 5. The orientation direction of one side of the inside and the outside of the hollow cylindrical body is 10 ° or more with respect to the center axis of the hollow cylindrical body, and the orientation direction of the other side is the center of the hollow cylindrical body. The impact energy absorbing member according to any one of claims 1 to 4, wherein the impact energy absorbing member is substantially parallel to an axis.