JPH11351300A - Shock absorbing body, and impact absorbing method using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impact absorbing body which is compact and lightweight, and simple in structure, absorbs the large energy compared with the reaction, and is available in a maintenance-free manner both on the ground and in the sea, and is excellent in energy absorption. SOLUTION: In this hollow cylindrical impact absorbing body formed of a resin of not less than 500 kgf/cm<2> in bending modulus of elasticity, the impact energy is absorbed by the deformation of a hollow cylindrical part 1 possible for large deformation, and the reaction-compression ratio curve during the compression in the longitudinal direction of the hollow cylindrical body satisfies the inequalities of the yield strength >=1,000 tf/m<2> , the compression energy absorption per unit volume >=200 tf.m/m<3> , and the degree of the deformation of an end part of the hollow cylindrical body in the direction orthogonal to the longitudinal direction of the hollow cylindrical body is <=1/2 of the degree of deformation of a center part of the part 1 for possible large deformation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin shock absorbing member which can be applied to a part which needs to absorb or mitigate an impact, for example, a side wall of a road or a quay, a floor or a wall of a building, and a collision buffer of a vehicle. The present invention relates to a shock absorbing structure using the same.

[0002]

2. Description of the Related Art Conventionally, as a shock absorbing means, a metal spring, a friction type shock absorber, a hydraulic type shock absorber, a rubber molded body, and the like have been used, and when any of these is used in combination. is there. Although the metal spring has excellent shock absorbing performance, it hardly absorbs collision energy.
In addition, the above-mentioned friction type shock absorber and hydraulic type shock absorber generally have a complicated structure, have a very large dependency on a deformation speed in a spring constant, and have problems such as lack of restorability.

[0003] The rubber molded article has a characteristic of good resilience, but the elastic modulus of the material is low. Therefore, in order to secure a satisfactory shock absorption, it is necessary to use a large amount of the material. However, there is a disadvantage that the weight of the member increases and the size of the member increases.

As a shock absorbing means using a resin molded article, the present inventors have made a resin molded article having a cushioning property in which a plurality of arch-shaped, dome-shaped or honeycomb-shaped compressed deformation portions are erected on a perforated or non-perforated flat plate. We have proposed a shock absorber made of a body. However, the shock absorber has a characteristic of exhibiting a uniform cushioning performance over a wide area such as a road side wall or a floor of a building, but is difficult to be applied when it must be installed in a very limited space. There was a problem.

Further, as a shock absorber made of a resin molding,
There has been disclosed a technique for manufacturing a resin molded article characterized in that a hollow molded article using a thermoplastic elastomer is compressed in the axial direction to give a permanent set in advance (Japanese Patent Publication No. Sho 61-12).
No. 779), but there is a problem that the resin molded article according to this technique has an excellent cushioning performance, but has a poor ability to absorb collision energy.

The present invention has been made in view of the above-described problems of the shock absorbing device, and has as its object the purpose of the present invention is to provide a small-sized, light-weight and simple structure that can significantly reduce the energy generated by an impact. An object of the present invention is to provide a shock absorbing device that absorbs, is excellent in rust prevention, waterproofing, and weather resistance, and can be used maintenance-free regardless of underground or underwater.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems of the conventional shock absorbing means, and has as its object a small, lightweight and simple structure. An object of the present invention is to provide a resin shock absorber having a large amount of compressive energy absorption as compared to a force and having excellent energy absorption ability.

[0008]

That is, the present invention relates to a hollow cylindrical shock absorber formed of a resin having a flexural modulus of 500 kgf / cm ² or more, and a seat for the large cylindrical deformable portion. Absorbs shock energy by bending deformation,
Reaction force during compression in the length direction of the hollow cylindrical body;
Using a resin shock absorbing material characterized in that the compression ratio curve satisfies the following (a) and (b), a direction perpendicular to the longitudinal direction of the hollow cylindrical body: Wherein the end of the hollow cylindrical body is easily deformed with respect to the central portion of the large deformable portion is equal to or less than half the deformability of the central portion of the large deformable portion. body. (A) The yield strength is 1,000 tf / m ² or more. (b) Compressed energy absorption per unit volume is 200
tf · m / m ³ or more. It is characterized by having excellent impact mitigation performance by reducing the ease of deformation of the end portion by various methods, such as a method of forming a flange portion on the opening side at the end portion of the hollow cylindrical body, for example. It is a shock absorbing structure.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The shock absorbing structure according to the present invention has a hollow cylindrical structure (resin shock absorbing material made of resin) formed of a resin having a flexural modulus of 500 kgf / cm ² or more. The elastic modulus is 500 kgf / cm ²
The above resins include various thermoplastic and thermosetting resins. Among them, particularly preferred are thermoplastic polyester elastomers and polyolefin elastomers having excellent weather resistance and water resistance, but the types thereof are not particularly limited as long as the flexural modulus falls within the above range.

Incidentally, the flexural modulus is 500 kgf / c.
If the resin is less than m ^2, the resin is elastically deformed and deformed immediately when an impact force is applied. In other words, the energy absorption amount is very small, so that satisfactory energy absorption performance cannot be provided.

On the other hand, the flexural modulus is 500 kgf /
If a resin of cm ² or more is used, the rise of the reaction force of the resin shock absorber can be accelerated as necessary, or the yield reaction force can be reduced by changing the shape of the large deformable part of the hollow cylinder described later. Because it can be made larger, it can be made into a small and lightweight shock absorber without making the thickness extremely thick like a conventionally used rubber molded body, and it is easy to break when compressed No more.

The shock absorbing material used in the present invention is made of a resin that satisfies the above requirements of the bending elastic modulus and is formed into a shape and a structure as described in detail below, so that the shock absorbing material can be totally absorbed. To be configured. 1 and 2 illustrate the structure of the shock absorber according to the present invention. FIG.
Then, flanges 2 are provided at both ends of the hollow large deformation movable portion 1.

In the shock absorber having the structure shown in the figure, the large deformable portion 1 is an elastic deformation or a buckling deformation or a buckling deformation portion for relaxing or absorbing an impact force. There is no restriction on the shape as long as it can be formed into various shapes and structures.

Further, the shock absorber used in the present invention is
In practical use, the number of installed shock absorbers can be arbitrarily set according to the degree of shock absorption energy required according to the application place. The yield strength confirmed by the reaction force-compression ratio curve when compressed in the direction of the arrow is 1000 tf /
m ² or more and the compression energy absorption is 200 tf · m
/ M ³ or more.

Here, the reaction force-compression ratio curve (hereinafter sometimes referred to as SS curve) is, for example, a reaction force (compression force / pressure receiving force) when a resin shock absorber is compressed in the direction of impact. 7 is a graph showing the correlation between the area and the compression ratio. In the initial stage of the compression, the SS curve rises sharply in proportion to the compression ratio, and then gradually becomes gentle (flat portion). Reaches the yield point at which the maximum reaction force is reached, where the resin shock absorber yields in the large deformation movable part, but the displacement of the reaction force generated in the entire compression area in the compression process is always positive Thereby, the impact relaxation effect can be further improved. In this compression process, if there is a part where the amount of displacement of the reaction force generated in the entire compression area becomes negative, the reaction force weakens during the compression deformation when receiving an impact, so a sudden deformation occurs and the impact is This makes it difficult to buffer. When the compression is further continued, the load-compression ratio curve rises sharply again due to the decrease in the gap, and the reaction force sharply increases with a slight increase in the compression ratio.

The yield strength in the SS curve of the present invention means a reaction force value which shows a maximum in a flat portion after the first rise, and the compression energy absorption amount per unit volume is substantially the maximum compressibility. It means a value obtained by dividing the amount of absorbed energy indicated by the area surrounded by the SS curve (shaded region in FIG. 3) when the compression is performed to the volume of the shock absorbing material.

Although the yield strength in the present invention does not always coincide with the maximum reaction force value in the entire SS curve of the shock absorbing structure, the impact object receives the impact force when the shock absorbing structure receives an impact force. This value is close to the maximum reaction force, and is considered as a guide for the maximum reaction force value. When the yield strength is insufficient, the function of the impact energy absorber is not substantially exerted. On the other hand, when the yield strength is too large, the reaction force generated at the time of impact becomes large and the impact cannot be satisfactorily reduced. In order to efficiently absorb impact energy, it is effective to make the first rise of the SS curve as sharp as possible and to minimize the decrease in the reaction force after passing the yield point.

As a result of examining the cushioning material according to the present invention from such a viewpoint, it is necessary to obtain a yield strength of 10 to sufficiently absorb the impact force without giving an excessive reaction force to the collision object.
00tf / m ² or more compression energy absorption amount 200t
cushioning material is required to have a f · m / m ³ or more capabilities.
In that respect, it is clear that the hollow cylindrical cushioning material of the present invention sufficiently satisfies the required characteristics.

In the case of a conventionally known shock absorbing material such as a rubber molded product, the rise of the SS curve is slow as shown in FIG. You have to use a lot of materials,
The weight of the member is increased, and the size must be increased.

On the other hand, a resin molded article which is obtained by compressing a hollow molded article using a thermoplastic elastomer disclosed in Japanese Patent Publication No. 61-12779 and applying a permanent strain thereto in the axial direction does not substantially undergo buckling deformation. Such a molded product exhibits an SS curve similar to that of a rubber molded product, and has poor ability to absorb collision energy.

On the other hand, the shock absorber structure of the present invention in which the bending elastic modulus of the resin is specified and its shape and structure are determined as described above, as shown in the schematic diagram of FIG. Not only is the initial rise steep, but after showing a moderate yield strength, the reaction force remains almost constant (flat portion) for a while even if the compression ratio is further changed, and then the final sudden rise Show, as a result, 200tf · m /
It has a very high compression energy absorption of at least m ³ . Further, in this compression process, the amount of displacement of the reaction force generated in the entire compression region needs to be always positive. When there is a negative portion of the displacement of the reaction force, when compression occurs due to impact, the deformation may occur rapidly, and sufficient energy cannot be absorbed.

There are no particular restrictions on the shape, structure, wall thickness, etc. of the large deformable portion in the form of a hollow cylinder, and it can be appropriately changed according to the application and purpose, as described above. But,
In order to secure the above-mentioned yield strength and compression energy absorption, the ratio of the large deformable portion height H to the outer shape R is R / H = 0,
It is preferable to select the shape so as to be in the range of 3 to 1,5. When R / H is less than 0 or 3, the large deformable portion becomes insufficient in height and the amount of energy absorbed by buckling deformation decreases, while when R / H exceeds 1, 5, the large deformable portion becomes irregular. This is because there is a tendency that the vehicle falls down easily in the direction.

In order for the above-mentioned SS curve to exhibit a substantially constant (flat portion) reaction force, it is desirable that the cavity portion of the large deformable portion does not undergo irregular deformation as described above. This can be prevented by making the end of the hollow cylindrical body easier to deform than half the central portion of the large deformable portion of the hollow cylindrical body. The ease with which the ends of the hollow cylindrical body can be deformed is preferably 1/3 or less, more preferably 1/5 or less, at the center of the large deformable portion of the hollow cylindrical body. Examples of the method of making the deformability of the end portion of the hollow cylindrical portion less than half of the central portion of the large deformable portion include, for example, a method of attaching a flange to the end of the hollow cylindrical portion, and an end of the hollow cylindrical portion. , A method of increasing the thickness of the end of the hollow cylindrical portion, and a method of attaching a reinforcing member (for example, a metal or resin ring) made of a material having a larger elastic modulus than the deformable portion to the end of the hollow cylindrical portion. This can be achieved by a method of attaching a plate having a convex portion that matches the inner shape of the tube at the end of the hollow cylindrical portion or a plate having a concave portion that matches the shape of the end of the hollow cylindrical portion.

For example, the flange will be described as an example. If there is no appropriate flange, the hollow portion falls down in the process of deformation of the large deformable portion and the displacement of the reaction force in the process of compressing the SS curve is reduced. I can't do it. There is no limitation on the shape or structure of the flange as long as it does not cause irregular deformation inside. As a flange, when molding the shock absorber with the same material as the shock absorber, it may be molded as a molded body having a flange, as well as fixed separately with an adhesive or a bolt after molding, A completely different material may be used as the flange and fixed to the shock absorber.

As described above, a desired SS curve cannot be obtained when there is no flange. However, when a flange cannot be formed due to restrictions such as installation space, a ring-shaped outer or inner end is formed. There is a method of attaching and inserting a reinforcing member. For example, if the method of preventing irregular deformation of the end of the hollow portion by a method such as directly winding a fibrous material around the hollow body or press-fitting a metal ring, the thickness of the ring-shaped reinforcing member, There are no restrictions on the restraining method and material. However, in order to secure the amount of compression energy per unit volume, the length of the ring is preferably 以下 or less, preferably １ ／ or less with respect to the height H of the large deformable portion. The outer shape of the ring-shaped reinforcing portion and the portion in contact with the hollow cylindrical portion are preferably at least 以上, preferably at least ６, the radius of the inner diameter of the hollow portion of the large deformable portion.

In short, the shock absorber, which is a resin-made cylindrical molded body, is used, and irregular deformation such as bending inward at the cavity of the large-deformable portion of the cylindrical molded body, particularly at the end, is not caused. The shock absorbing structure thus devised is the present invention, and in order to prevent the irregular deformation from occurring, the hollow cylindrical end is easily deformed by one of the central portions of the large deformable portion. / 2 or less. Preferably it is 1/3 or less, more preferably 1/4 or less. The ease with which the hollow cylindrical body is easily deformed is measured as follows. Using a Tensilon compression tester, the shock absorbing structure was sandwiched between stainless steel jigs (up and down) having a contact surface with the sample of 10 × 300 mm and compressed at a speed of 20 mm / min. The distance between the jigs at the moment when the load is detected (that is, the outer diameter of the measuring point of the hollow cylindrical body when there is no load) is (a), and the distance between the jigs when a load of 5 kgf is (b) is , ((A)-
(B)) / (a) × 100 is used as an index of the ease of deformation at that location. Large deformable part center: Midpoint from both ends of flange and reinforcing part Deformability of end: 10 mm away from flange and reinforcing part In measurement, the shock absorber was incorporated into a large-scale structure and Tensilon was used. When the measurement cannot be performed with a compression tester, a model that functions as a shock absorbing structure substantially similar to a real product may be formed using the same resin shock absorber, and the measurement may be performed. Further, in a state where the shock absorbing structure is incorporated in the structure, a load of 5 kgf may be applied to the shock absorbing structure using a jig similar to the Tensilon compression measuring instrument, and the load may be calculated from the displacement amount of the shock absorbing structure.

The impact absorbing material used in the present invention is provided with a dash pot and a spring-like energy absorption behavior by combining the viscoelastic properties of a resin having a moderate bending elasticity and its shape as described above. Thus, the impact energy can be absorbed very efficiently.

As a method for producing the resin shock absorber according to the present invention, any method such as injection molding, extrusion molding or press molding can be adopted. In addition, the resin shock absorber of the present invention can adopt a normal mounting method, for example, a method of mounting the shock absorber on another structure through a hole provided in a flat plate portion constituting the shock absorber. Is not limited at all.

The preferred types of the resin used in the present invention are as described above, and these resins may be added to various stabilizers such as, for example, a thermal antioxidant and an ultraviolet absorber according to the application or purpose. Fillers such as dyes and pigments, carbon black, talc and glass beads, fibrous reinforcing agents such as metal fibers, glass fibers and carbon fibers, antistatic agents, plasticizers, flame retardants, foaming agents, mold release agents, etc. It is also possible to modify by adding an additive.

[0030]

The present invention is configured as described above.
Use a resin with a specified flexural modulus, and
By specifying the structure, it is possible to provide an impact structure having excellent impact absorption characteristics due to the elastic properties of the resin and the buckling deformation of the molded body, and exhibiting high impact energy absorption capacity while being compact and lightweight. is what happened. The shock absorber can be widely applied to, for example, the side wall of a road or quay, the floor or wall of a building, and the shock absorbing portion of a vehicle by utilizing its excellent characteristics.

[0031]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following Examples and is not limited to the following Examples. Any of the modifications is included in the technical scope of the present invention.

Example 1 Using a polyester elastomer "Perprene P-55B" manufactured by Toyobo Co., Ltd.
The hollow cylindrical cushioning material shown in FIG. 1 (height 100 mm, outer diameter 8
0 mm). Table 1 shows the results of compression in the following evaluation method. Example 2 Using a polyester elastomer "Perprene P-55B" manufactured by Toyobo Co., Ltd., a hollow cylindrical cushioning material (height 100 mm, outer diameter 80 m) shown in FIG.
m) was used. Table 1 shows the results of compression in the following evaluation method.

[Comparative Example 1] A polyester elastomer "Perprene P-55B" manufactured by Toyobo Co., Ltd. was used.
The hollow cylindrical cushioning material (height 100 mm, outer diameter 8
0 mm). Table 1 shows the results of compression in the following evaluation method. The ease of deformation of the end of the hollow cylindrical body / the ease of deformation of the center of the large deformable part is 2
/ 1. [Comparative Example 2] Table 1 shows the result of cutting a commercial rubber ingot having a hardness of 63A in the same shape and size as in Example 1 and compressing it. The ease of deformation of the end of the hollow cylindrical body / the ease of deformation of the center of the large deformable portion was 1/7.

[Evaluation method] Flexural modulus: commonly used ASTM-D79
Measured by 0. Impact receiving surface area: Refers to the flat plate contact area at the end of the large deformable portion. Yield strength: The unit area of the impact force receiving surface when the reaction force-compression ratio curve rises almost in proportion to the compression ratio at the beginning of compression, and then gradually becomes gentle (flat portion) to reach the maximum reaction force. It refers to the strength around. Compressive energy absorption per unit volume: Refers to the energy absorption per unit volume of the shock absorber when compressed to substantially the maximum compression in the reaction force-compression ratio curve. Ease of deformation: Using a Tensilon compression tester, the shock absorbing structure was sandwiched between stainless steel jigs (up and down) having a contact surface with a sample of 10 × 300 mm and compressed at a speed of 20 mm / min. The distance between the jigs at the moment when the load is detected (that is, the outer diameter of the measuring point of the hollow cylindrical body when there is no load) is (a), and the distance between the jigs when a load of 5 kgf is (b) is , ((A)-(b)) / (a) × 100 was used as an index of the easiness of deformation at that location. (Easiness of deformation of Examples and Comparative Examples is described in Table 2.) Center of large deformable portion: Midpoint from both ends of flange and reinforcement portion Deformability of end portion: Location 10 mm away from flange and reinforcement portion

Table 1 shows the results of the evaluation of the shock absorbing structures of Examples 1 and 2 and Comparative Examples 1 and 2.

[0036]

[Table 1]

As is clear from Table 1, the shock absorbing body of the present invention is much more excellent in absorbing shock energy than the conventional shock absorbing body. Moreover, this device can be used in the air and in the sea without any trouble,
It has excellent water resistance and weather resistance and is maintenance-free.

FIG. 6 shows the SS curves of the shock absorbers of Examples 1 and 2 and Comparative Example 1. The SS curves of Comparative Example 1 do not show a substantially constant reaction force. Energy absorption efficiency is poor as compared with the SS curve.

FIG. 8 shows that the shock absorber of Example 1 and the shock absorber of Comparative Example 2 have a slow rise of the SS curve and thus have poor shock absorbing ability. It has a yield strength, does not exert an extreme reaction force on the colliding object, and has an SS curve that is closer to a rectangle than that of Comparative Example 2 and has extremely excellent energy absorption efficiency. It can be seen that it is.

[Brief description of the drawings]

FIG. 1 is a sketch showing a typical example of a shock absorbing material according to the present invention.

FIG. 2 is a schematic view illustrating another absorbent material according to the present invention.

FIG. 3 is an explanatory diagram illustrating a load (reaction force) -compression ratio curve of the shock absorber of the present invention.

FIG. 4 is an explanatory diagram illustrating a load (reaction force) -compression ratio curve of a normal rubber elastic body.

FIG. 5 is a sketch illustrating the shock absorber of Comparative Example 1.

FIG. 6 is an explanatory diagram showing load-compression ratio curves obtained in Examples 1 and 2 and Comparative Example 1.

FIG. 7 is an explanatory diagram illustrating a load (reaction force) -compression ratio curve of the shock absorber of the present invention.

FIG. 8 is an explanatory diagram showing load-compression ratio curves obtained in Example 1 and Comparative Example 2.

[Explanation of symbols]

 1 Large deformable part 2 Flange 3 Reinforcement

Claims (8)

[Claims] 1. A hollow cylindrical shock absorber formed of a resin having a flexural modulus of 500 kgf / cm ² or more, wherein the hollow cylindrical large deformable portion deforms to absorb impact energy, The reaction force / compression rate curve at the time of compression in the length direction of the cylindrical body is shown in the following (a) and (b).
Using a resin shock absorber characterized by being configured to satisfy the following, the end of the hollow cylindrical body with respect to a direction perpendicular to the longitudinal direction of the hollow cylindrical body Ease of deformation is half of the ease of deformation at the center of the large deformable part
A shock absorbing structure characterized by the following. (A) The yield strength is 1,000 tf / m ² or more. (b) Compressed energy absorption per unit volume is 200
tf · m / m ³ or more. 2. The shock absorbing structure according to claim 1, wherein a flange portion is formed on an end opening side of the hollow cylindrical body. 3. The shock absorbing structure according to claim 1, wherein the end of the hollow cylindrical body is closed. 4. The shock absorbing structure according to claim 1, wherein the thickness of the end of the hollow cylindrical body is larger than the thickness of the hollow cylindrical portion. 5. The shock absorbing structure according to claim 1, wherein a reinforcing member made of a material having a higher elastic modulus than the large deformable portion is attached to an end of the hollow cylindrical body. 6. The shock absorbing structure according to claim 1, wherein a portion having a convex portion that matches the inner shape of the tube at the end of the hollow cylindrical body is attached. 7. The shock absorbing structure according to claim 1, wherein a concave portion and / or a portion having a concave portion corresponding to the shape of the end of the hollow cylindrical portion are attached. 8. The method of claim 1, 2, 3, 4, 5, 6, or 7.
A method for absorbing a shock using the shock absorbing structure according to any one of the above.