JP2008180378A - Impact force buffer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impact force buffer device compactly and inexpensively manufactured and providing stable resistance characteristics. <P>SOLUTION: In this impact force buffer device, a buffering part is inserted between an external force receiving part and a fixed part which are arranged along a force buffering direction to thereby absorb impact force. The buffering part 6 is provided with shock absorbing members 8 which are so arranged that their front and rear surfaces are directed in the force buffering direction, and insertion rods 12 having each one end opposed to at least one of the front and rear surfaces of the shock absorbing members and parallel to the force buffering direction. One side of each of the shock absorbing members 8 and insertion rods 12 is interlocked with the external force receiving part 4, and also the other thereof is linked with the fixed part 16, thereby performing buffering. Therefore, when impact force is applied to the external force receiving part 4, the insertion rods 12 collides with a part of the front or rear surfaces of the shock absorbing members 8. The shock absorbing members 8 are made of materials into which the insertion rods can penetrate by cave-in of the collided portions. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an impact force shock absorber, in particular, a shock shock absorber between a vehicle (automobile or railcar) and a traffic road, or a shock absorber between an interior material inside a vehicle and a passenger's body.

  However, as a use other than this, the apparatus of the present invention can be used as various shock absorbing means such as a shock absorber in the case of an elevator dropping accident or a shock absorber between a building and a foundation in the event of an earthquake.

  Conventionally, in various parts of buildings and transportation facilities, shock absorbing means for absorbing impacts have been applied in order to minimize damage from accidents and disasters.

For example, to protect the vehicle occupants in a traffic accident, a plurality of shock absorbers and weights (inertial mass bodies) formed of expanded polystyrene or aluminum honeycomb bodies are repeatedly applied in the road direction at the end of the highway separation zone. It is known that they are juxtaposed for a long time, and the shock absorber is crushed by a vehicle collision to absorb energy (Patent Document 1 and Patent Document 2). Also known is a case in which a shock absorber case long in the road direction is formed of a rubber plate and energy is absorbed by the elastic force of the rubber (Patent Document 3).
Further, as a shock absorber mounted on a vehicle, one that is used for a bumper or the like that is formed by filling an inside of a honeycomb core with an elastic material is known (Patent Document 4). Furthermore, a shock absorber provided in such a manner that a rod body whose tip is bonded into the hole of the punch plate is recessed into the hole deeper by cutting the bonded part is embedded in a pillar (pillar) that supports the roof of the automobile. (Patent Document 5).
JP2003-64629 JP 2000-274472 A JP 2001-200513 Actual Kaihei 7-49095 JP-A-2005-219558

  As in Patent Documents 1 and 2, when a material having low strength and high deformation performance, such as foamed polystyrene or an aluminum honeycomb body, is used as a shock absorber for vehicle collision, input acceleration to the human body can be reduced. On the other hand, since the buffer is simply compressed, the amount of deformation is 70% or more of the original length. In order to secure a suitable crushing allowance, the entire apparatus becomes long and large, and it is difficult to make it compact. Further, when the material is formed in a honeycomb structure, the manufacturing cost is increased.

  On the other hand, when the adhesive part is cut by impact as in Patent Document 5 and the plug body is recessed into the hole, the acceleration at the initial stage of collision becomes excessively large, and conversely, an elastic material is used as in Patent Documents 3 to 4. Sometimes, the elastic force depends on the deformation rate, so that it is impossible to maintain a stable deformation resistance.

  An object of the present invention is to provide a shock absorbing device that is compact and can be manufactured at low cost, and that provides stable resistance characteristics.

The first means is
An impact force buffering device that reduces the absolute value of the maximum acceleration at the time of collision by inserting a buffer part between the external force receiving part and the fixed part arranged along the direction of buffering the force and absorbing the impact force,
The cushioning portion 6 is parallel to the force cushioning direction, with the cushioning material 8 arranged with the front and back surfaces facing each other in the force cushioning direction, and at least one end faced to one of the front and back surfaces of the cushioning material. A rush bar 12;
When one of the cushioning material 8 and the rush bar 12 is interlocked with the external force receiving portion 4 and the other is braked in cooperation with the fixing portion 16, an impact force is applied to the external force receiving portion 4. The entry bar 12 is provided so as to strike a part of the front surface or the back surface of the cushioning material 8;
The cushioning material 8 is formed of a material capable of penetrating the rush bar by the depression of the hitting portion.

  This means proposes a shock absorber that can reduce the absolute value of the maximum acceleration at the time of collision and at the same time increase the arrival time to the maximum acceleration. For this purpose, a collision rod is opposed to a part of the buffer material, and the collision energy is absorbed by causing the shock rod to penetrate into the buffer material due to an impact. FIG. 6 shows a change in stress with respect to the deformation amount by a method of simply compressing the entire cushioning body such as a foam and a method of penetrating a plunge rod. In the former, the rise of stress at the initial stage of impact is large, and when the deformation exceeds a certain value, the compression limit is reached and the stress rapidly increases. In the latter case, the entry rod is a method of locally shearing and crushing the cushioning material, and if the size of the tip surface of the entry rod is appropriately designed, the material penetrates so as to break through the material. A gentle resistance characteristic can be obtained throughout. Therefore, when used as a buffer for transportation or facilities used by humans, the influence on the human body can be reduced.

  The “buffer material” has a function of absorbing kinetic energy by the penetration of the entry rod. “Penetration” includes penetration, but also includes the case where the tip of the penetration rod does not protrude from the opposite side of the buffer rod. The buffer material shall have sufficient strength against rapid deformation. The specific strength is set according to the application, but for vehicle collision buffering, it is desirable that the strength be about 2 to 60 MPa (more preferably about 4 to 30 MPa). In addition, as the material of the cushioning material, by hitting the plunging rod, the location will be depressed, and the cushioning material will not break or crack as a whole due to the penetration of the rushing rod, so that it can be broken locally . For example, a metal cell structure, a mortar material having pores, or various wood materials having a cell structure such as balsa, willow, and beech are applicable. FIG. 17 is an enlarged view of a cross section of a hinoki, which shows a hollow cell structure. The “metal cell structure” refers to a metal material having a porosity of about 70% or more.

  The “plunging bar” is at least harder than the buffer material and has a function of penetrating the buffer material. Suitable materials for the entry rod include iron (steel) and FRP (fiber reinforced plastic). In addition to being hard, it is desirable that consideration should be given to weight reduction, such as toughness (toughness) that does not buckle or break during penetration, and hollowing so that inertia is small. In the present specification, the “rod” is sufficient if it has the above penetration function and has a certain penetration length.

  The shape of the plunging rod may be designed so that it can smoothly penetrate the cushioning material over the entire length of the rod. For example, in addition to a round bar or a square bar, a rod having an arbitrary cross-sectional shape (for example, a cross) It may be a body. In addition, an ordinary straight bar having a flat end surface and a constant diameter may be used. However, as will be described later, a taper taper may be provided on the entire rod or the peripheral surface of the tip. Further, it may be a solid pin, but it may have a pipe shape with an open end. As will be described later, the initial acceleration at the time of collision is reduced in the order of a solid bar with a flat end → a solid bar with a taper → a hollow bar. An appropriate structure may be selected. For example, in the case of a shock absorber installed in a separation zone on a motorway, it is appropriate to use a tapered solid rod in consideration of both passenger safety and the amount of energy to be absorbed. For the unmanned elevator fall prevention device, it is sufficient to use a solid end flat solid bar.

  The number of rush bars, the rush length, and the diameter are designed according to the magnitude of the impact force to be buffered. It is considered that the resistance force (and the absorbed energy) when a suitable number of plunging rods having the same diameter and plunging length are plunged into one cushioning material increases in proportion to the number. The reason for this is that, according to the experiment, the deformation site formed as a result of the passing of the entry rod during buffering is limited in the direction perpendicular to the deformation, and hardly spreads to other regions. Therefore, if the resistance per rush bar is obtained by experiments, the required number of rush bars can be estimated from the required resistance value, which is convenient in design. The diameter (or cross-sectional area) of the plunging rod is large enough to prevent the plunging rod from breaking or bending due to penetration into the cushioning material, depending on the strength of the cushioning material, and to penetrate smoothly into a part of the cushioning material. Provide small. The diameter of the rush bar is preferably larger than the cell size. This is because it is preferable that the cell structure is continuously crushed according to the progress of the rush, rather than the rush proceeding only by the rupture of the cell wall.

The second means includes the first means, and the cushioning material 8 is formed of a perforated material or a cell structure including a hole smaller than the diameter of the entry rod 12, and
Moreover, the bumping portion is provided so that the bumping portion is locally crushed without being broken by the entire cushioning material 8 by the bumping of the rush rod.

  In this means, the cushioning material is made of a perforated material or a cell structure, so that it can be locally crushed with a rush bar. That is, only the hitting location can be crushed by destroying the cell wall portion of the material portion or structure other than the holes. The cell structure may be either an open cell or a closed cell, but the closed cell provides a higher resistance.

    The third means includes the second means, and the shock absorbing material 8 has an impact pressure strength of 2 to 60 MPa at a collision speed of 5 to 120 km / hour.

In this means, it is proposed that the impact pressure strength is increased to reduce the volume of the buffer material and to make the buffer device compact. For example, by using an alloy having a composition of Al-3.0 (wt%) Mg-1.4 (wt%) Ca-1.4 (wt%) Ti (+ unavoidable impurities), the strength of at least 10 to 30 MPa is achieved. can get. The following table shows a comparison between the strength of this composition and the strength of known buffer materials, and the greater the strength, the greater the amount of energy absorption. In the present invention, a resistance force is obtained by local destruction of the buffer material by the piercing of the entry rod. Therefore, it is important that each part of the buffer material has a large deformation resistance. In order to further increase the strength to 30 to 60 MPa, the concentration of each alloy element may be increased or, more simply, the porosity may be decreased.

The fourth means has any one of the first means to the third means, and the tip of the penetration rod 12 for penetrating into the cushioning material 8 has a tapered shape that narrows toward the tip. .

  In this means, the entry rod is tapered to prevent the initial acceleration from increasing in the process of entering the buffer material 8, and the arrival time up to the maximum acceleration can be controlled longer. FIG. 6 shows the result of an experiment on the characteristics of acceleration between an entry rod with a tapered tip and an entry rod with a flat tip surface, and it can be seen that the acceleration is actually reduced. This experiment will be described later. In addition to the shape in which only the tip portion is a tapered end portion, the tapered piercing rod includes a shape in which a taper is gradually tapered from the root to the tip. Further, when the entry rod is a round bar or a square bar, the tapered tip may be formed into a cone (cone or pyramid) or a frustum shape. In this case, the tapered tip portion may be formed in a wedge shape when viewed from the left and right sides. The taper angle (the angle formed between the surface perpendicular to the entry rod and the taper surface) is designed according to the application of the shock absorber. When the collision speed is low, the taper angle can be made smaller.

    In general, the tip portion of the cone shape is more easily pierced than that of the truncated cone shape, and is effective in reducing the initial impact force. However, if it is too sharp, the contacting cell wall is easily broken and penetrated, which may cause a reduction in strength as a shock absorber. In addition, the size of the cone- and frustum-shaped tapers determines the intensity of how the cells are divided. Deformation resistance is determined by their interaction, and it is necessary to balance each action.

The fifth means includes any one of the first means to the fourth means, and a plurality of parallel entry rods are arranged on at least one of the front and back sides of the cushioning material 8 as the entry rod, and the external force receiving When the impact force is applied to the portion 4, the buffer rods 8 are provided so that the plurality of protruding rods 12 penetrate from one side to the inside thereof.

  In the present invention, a stable deformation resistance is obtained by the penetration of the entry rod into the cushioning material. However, the resistance force obtained from one entry rod is smaller than when the same type of cushioning body is compressed as a whole. Therefore, in this means, an appropriate buffer performance can be obtained by adjusting the number of rush bars. These entry rods are preferably arranged so that the sum of the impact force transmitted from each rod passes through the vicinity of the center of gravity of each cushioning material.

Here, the density at which the rush bar is arranged will be mentioned. When two adjacent plunge bars advance through each cell, the cells in the path are completely crushed and become a state without a void (dense state). At that time, between the two entry rods, the densified cells from each rod side further crush the cell structure between the rods. If it demonstrates using numerical formula, the densification distortion | strain at this time will be given by (epsilon) = 1-1.4 * ((rho) ^* / (rho) _s ). Here, ρ ^* is the density of the cell structure, ρ _s is the density of the bulk material having the same composition, and (ρ ^* / ρ _s ) is the relative density of the cell (ratio of the density of the bulk material having the same composition to the cell structure). ). When (ρ ^* / ρ _s ) = 0.2 to 0.3, ε _p = 0.72 to 0.58. That is, since the cells in the area of 10 mm radius of the push rod 20φ are densified after being deformed by 7.2 to 5.8 mm, the remaining cells of 2.8 mm to 4.2 mm are pushed out from the outline of the rod. It will be. Since this phenomenon occurs from both sides of the adjacent rods, if used this time cells, it comes to it there is a clearance A _C of 5.6～8.4Mm. This is expressed by an equation: A _C = r × (1−εp) × 2. Where r is the radius of the bar. 1-ε _p is called compression limit strain.

The sixth means includes any one of the first means to the fifth means, and the buffer section 6 includes a plate-shaped buffer material 8 perpendicular to the force buffering direction, and a front surface or a back surface of the buffer material. A buffer unit 10 composed of a protruding bar portion facing at right angles to a part of the buffer unit 10 is provided so as to be movable in the buffer direction in tandem with the buffer direction;
Of the series of shock absorbing units, the shock absorbing member 8 or the penetrating rod portion of the first unit is connected to the external force receiving portion 4, and the shock absorbing member 8 or the penetrating rod portion of the last unit is connected to the fixing portion 16, respectively.
When an impact propagates from the external force receiving portion 4 to the fixed portion 16 through each buffer unit 10, reaction force is obtained from an adjacent unit on the fixed portion 16 side in each shock unit, and the rush rod 12 enters the buffer material 8. To penetrate.

  In this means, a larger shock can be absorbed by connecting a plurality of buffer units. In each buffer unit, the buffer material may be formed so that the piercing bar penetrates only from one side of the front and back surfaces, or may be provided so that the piercing bar penetrates from both sides as described later. . In this specification, the buffer unit refers to a unit of a mechanism for buffering and absorbing force for each buffer material, and is formed by at least the buffer body itself and a piercing bar portion penetrating into the buffer body. Yes. Here, the term “rush bar portion” rather than the “rush bar” is because a case is assumed in which one half and the other half of one rush bar are part of another buffer unit. This will be described later.

The seventh means includes the sixth means, and the buffer unit 10 is formed by the buffer material 8 and a plurality of piercing rod portions respectively arranged on both the front surface side and the back surface side of the buffer material 8. In addition, the rush rods 12 are arranged on different axes so that the cross sections of the rush rod on the front surface side and the rush rod on the rear surface side do not overlap when viewed from the force buffering direction.

  In this means, the shock absorbing device has a simple and compact structure by inserting the sticking rods from both sides of the shock absorbing material. In other words, when penetrating rods are inserted from both sides of the cushioning material, the number of penetrating rods that can be penetrated for each cushioning material increases, and the amount of energy absorption increases, so the required amount of shock is buffered with a small number of buffering units. it can. Of course, it is not impossible to penetrate a large number of rods even from one side of the shock absorber, but if the gap between the rods is excessively small, the simple compression method of the shock absorber will be approached and the acceleration at the beginning of the collision will increase. Become big.

The invention according to the first means has the following effects.
○ Since the rush bar 12 pierces a part of the cushioning material and penetrates while scraping the material, it can maintain a stable deformation resistance in the entire range of the penetration stroke. For example, when used as a vehicle collision buffer device Less shock to the passenger's body.
-It can be manufactured at a lower cost than those using a honeycomb structure as a buffer material.

  According to the invention relating to the second means, since the buffer material 8 is easily formed by local crushing with the perforated material or the cell structure, the entire buffer material 8 is cracked by the penetration of the entry rod 12, and this destruction It is possible to prevent the deformation resistance from becoming unequal before and after.

  According to the third aspect of the invention, by using a material having high strength and excellent deformation performance, energy absorption characteristics are improved, and the bulk of the cushioning material 8 is reduced.

    According to the invention relating to the fourth means, since the end of the penetrating rod 12 for penetrating into the cushioning material 8 is a tapered tapered end, the initial acceleration during the process of penetrating into the cushioning material 8 is increased. Can be suppressed.

  According to the fifth aspect of the invention, an appropriate shock absorbing performance can be obtained by adjusting the number of the penetrating rods, and the impact force can be distributed to the entire cushioning material by adjusting the position of the penetrating rods. The material can be prevented from cracking at once.

  According to the sixth aspect of the invention, since a plurality of buffer units are provided, a large impact can be absorbed.

According to the seventh aspect of the invention, the following effects are obtained.
○ By penetrating the entry rods 12 from both sides of the cushioning material 8, a large number of entry rods can penetrate into one cushioning material and a large amount of energy can be absorbed, so that the apparatus can be made compact as a whole.
○ Since an appropriate number of piercing rods are inserted from both the front and back sides of the cushioning material 8, the compression stress of the cushioning material portion on the rushing surface side is increased compared to when the same number of rushing rods are pierced from only one side. Therefore, an increase in acceleration at the beginning of the collision can be suppressed.

  1 to 11 show a first embodiment of an impact force buffering device according to the present invention.

  First, a conventionally known part of the configuration of the impact force buffering device will be described. The device is formed by the support 2, the external force receiving unit 4, the buffering unit 6, the fixing unit 16, and the cover 18. The support base 2 extends long along the direction of the road in the vicinity of the branch portion on the road surface of the expressway. And the external force receiving part 4, the buffer part 6, and the fixing | fixed part 16 are mounted on the support stand in order from the side which a motor vehicle approaches. At least the external force receiving portion 4 and the buffer portion 7 are formed on the support base 2 so as to be slidable by a vehicle collision. Further, the cover 18 is formed so as to be crushed by a car collision.

  In the present invention, the external force receiving portion 4 that is a receiving plate and the fixing portion 16 that is a fixing plate are each formed of a tough material such as a steel plate, and are each made of steel in the opposite direction from each steel plate. A number of one entry rods 12A are integrally projected. The protruding lengths of the respective protruding rods are the same, and the tip portions of the protruding rods are formed at the tapered end portion 14.

  Further, a plurality of thick plate-like cushioning materials 8 are juxtaposed at equal intervals between the external force receiving portion 4 and the fixed portion 16. The outer rod of the outermost shock absorbing material is placed in close proximity to the above-described external force receiving portion 4 and the protrusion rod 12 protruding from the fixing portion 16. Further, between the cushioning materials, a steel second entry rod 12B having a length about twice as long as the first entry rod 12A is installed. In the example shown in the drawing, both end portions of the piercing rod are formed in the tapered end portions 14 and these end portions are fitted in the recessed portions formed in the respective cushioning materials, but the structure can be changed as appropriate. it can.

  In FIG. 2, the leftmost shock absorber 8, the first entry rod 12 </ b> A, and the left half of the second entry rod 12 </ b> B form one shock absorber unit 10. The material 8, the first entry rod 12 </ b> A, and the right half of the second entry rod form another buffer unit 10. Further, the inner cushioning material, the right half of the left entry rod 12B and the left half of the right entry rod 12B constitute a buffer unit. And the buffer part 6 is formed by connecting these buffer units.

  In the illustrated example, the first entry rods 12A are planted vertically and horizontally on the opposing surfaces of the receiving plate and the fixed plate, and the second entry rods 12B are similarly arranged vertically and horizontally. Further, as shown in FIG. 3, the rush rods 12 are arranged in a staggered manner so as not to collide with each other when penetrating into the cushioning material.

  Each buffer material 8 is formed of an Al—Mg alloy cell structure having a strength that allows the rush rods 12 </ b> A and 12 </ b> B to penetrate due to an impact caused by an automobile collision.

  In the above configuration, when the automobile collides with the external force receiving portion 4 in FIG. 3, the first entry rod 12A moves to the surface of the shock absorbing material 8 on the left side of the drawing (the left surface in the drawing) together with the external force receiving portion. Since the second entry rod 12B is in contact with the back surface of 8, the reaction force from the entry rod (or the adjacent cushioning material) is obtained, and the entry rod 12 penetrates the front surface or the back surface of the cushioning material 8, respectively. To do. In the same manner, the rush rods sequentially penetrate the other cushioning materials 8 and are compressed as shown in FIG.

  FIG. 6 shows the relationship between the amount of deformation and the stress in the method of the present invention in which the tip-shaped piercing rod penetrates the buffer material made of the cell structure described above and the simple compression method. In the simple compression method, since the entire cushioning material is compressed, a large stress is generated at the beginning of the collision. However, when the tapered piercing bar penetrates, the initial stress is small. In the simple compression method, when all of the cushioning material is crushed, the stress suddenly increases at a relatively early stage and the stress rapidly increases. Stable and constant stress can be maintained. The material compressed in the figure is the aforementioned Al-3.0 (wt%) Mg-1.4 (wt%) Ca-1.4 (wt%) Ti alloy.

FIG. 7 shows the results of a compression test on the aforementioned Al—Mg—Ca—Ti cell structure and a normal Al—Ca—Ti cell structure. According to this result, the former absorbs about 10 times as much energy. In addition, this experiment showed the result implemented by strain rate 10 < ^-3 > s < ^-1 > by the simple compression system (what is called a uniaxial compression test) instead of the spike system like this invention. From the known report example, at the impact deformation speed (for example, 20 to 60 km / hour), the stress is 1.0 to 2.0 times the static speed.

  FIG. 8 shows the result of an impact load measurement experiment using a flat end portion and a tapered end portion when the rush bar is inserted into the cushioning material. One of the specimens has a flat end surface with a diameter of 20 mm, and the other has a shape with a diameter of 2 mm on the tip surface through a taper of 90 mm and a diameter of 20 mm. As an experimental device, as shown in FIG. 9, a device for driving a rush rod into a test body was used. In addition, the speed immediately before the entry measured using the non-contact displacement type was 57 km / hour when a rod having a weight of 0.85 kg was used. FIG. 10 is a sketch of the cross-sections of two specimens after impact pressing. According to this, when the flat end portion is pierced, the cell portion pushed by the end face is crushed (FIG. (A)), whereas when the tapered end portion is pierced, the end portion The size of nearby cells is not much different from the outside (Fig. (B)). Thus, it can be seen that the plunge bar with the tapered end penetrates the cell structure. Further, according to this experiment, the maximum load is 8.8 kN for the flat end portion, and 6.06 kN for the tapered end portion. The maximum load reached by collapsing the cell structure can be reduced by about 30% of the impact load applied under the same conditions, and at the same time, the time required to reach the maximum load can be increased by about 4 times. Thus, it can be seen that this is effective from the viewpoint of energy absorption corresponding to collision safety.

  However, it is not essential that the end be tapered as a constituent requirement of the present invention. If it is a means of transportation other than passengers, the standard of 20G is not an absolute condition, and if the diameter of the rush bar can be reduced from the beginning, the standard may be cleared. However, in the case of automobile shock buffering, it is simply not easy to secure the required strength with the diameter.

  FIG. 11 is a modification of the first embodiment. In this example, a plurality of entry rods 12 are connected and connected to one surface of a plate material (connection plate) 20. The structure is the same as the structure in which the rush bar protrudes from one surface of the right plate which is the external force receiving portion.

[Example]
A configuration is designed for a case where an automobile with a vehicle weight of 1500 kg collides at 55 km / h to suppress the impact acceleration to 20 G or less.

  As the buffer material, four Al-Mg-Ca-Ti cell structures having a width of 600 mm, a length of 400 mm, and a thickness of 200 mm are used.

  A receiving plate and a fixing plate having a width of 600 mm and a length of 400 mm are used. 4 × 6 = 24 entry rods are attached to the inner surface of each plate. Each entry rod has a length of 160 mm, a thickness of 20 mm, a tip with a taper of 90 °, and a diameter of the tip surface of 2 mm. The length of the pin between the cushioning materials is 320 mm or more. A similar number of rush bars are also arranged between each cushioning material. Further, it is sufficient that the buffering direction of the device force is about 2100 mm. When a conventional aluminum honeycomb is used, a length of about 3000 mm is necessary to give the same performance, and the apparatus can be made more compact than that. In this specific example, the kinetic energy (175 kJ) when a vehicle weighing 1500 kg is running at a speed of 55 km / h is absorbed by the eight layers of buffer, so the absorbed energy per layer (21.9 kJ) Is calculated. The number of pins required per layer was determined by dividing the depth of penetration of the pins into the cushioning material, that is, the absorbed energy per location derived from the relationship between the deformation amount and the absorbed load (FIG. 8). It should be noted that the maximum acceleration generated when 48 tip 90 ° taper / push-in rods are used by the above method is 19.8G, and the maximum acceleration when a flat plunge rod is used with the same arrangement. It can be seen that the safety standard is satisfied for 28.7G.

  FIG. 12 shows a second embodiment of the present invention. In this embodiment, the shock absorbing device of the present invention is incorporated in the support structure of the safety board B in the automobile. That is, the safety board is connected to the fixed plate that is the fixed portion 16 via the receiving plate that is the external force receiving portion 4 at the edge of the safety board, a plurality of protruding rods that protrude from the receiving plate, and one cushioning material 8. . This fixing plate may be connected to a proper position on the inner surface of the automobile. As the material of the buffer material 8, a soft material that guarantees acceleration that does not damage the brain is used. Specifically, a material having a low plateau stress (steady state stress appearing after yielding), for example, a polymer material is suitable. is there. Moreover, when using a metal cell structure, it is preferable to simply use a metal cell structure having a porosity as high as about 95%. In the illustrated example, an elastic plate 22 is interposed between the safety board B and the external force receiving portion 4 to further weaken the impact, and the outside of the shock absorber is covered with a flexible hood 24.

  13 to 17 show a third embodiment of the present invention. In this embodiment, a wood material is used as the cushioning material 8. In particular, conifers such as cedar and cypress are preferred. This is because conifers are long, dense and soft. FIG. 17 is a plane crossing the wood at right angles to the fiber direction. In FIG. 17, the fibers of the wood extend perpendicular to the paper surface. Moreover, in FIG.13 and FIG.14, the fiber is represented by the thin line. The advantages of wood materials are that they have the same or better strength than aluminum alloy cell structures, but are overwhelmingly cheaper than aluminum alloy cell structures, and can use waste materials such as thinned wood. Contributing to the effective use of resources and being environmentally friendly because it is a natural material. On the other hand, since wood is formed of fibers, there is a possibility that it will be torn by inserting the rush rod 12. In order to prevent this, it is preferable to use a metal having a sharp tip compared to that used for the metal cell structure. In the illustrated example, a diameter of 20 mm, a tip surface diameter of 2 mm, and a tip angle of 60 degrees are used. The plunge rod 12 may be plunged in the direction of the fiber as shown in FIG. 13, or may be plunged in the direction perpendicular to the fiber as shown in FIG. The experimental data as the basis for this will be shown below.

  FIG. 15 shows the result of a static compression experiment using the cushioning material 8 as wood. An experiment was conducted for each of the cases of compressive deformation in a direction perpendicular to the fibers of the wood and the case of compression deformation in a direction parallel to the fiber direction. As a result, the following was found. First, there is a plateau region that is stable up to near compression strain of 0.6 in both the fiber direction and the fiber orthogonal direction. This is because wood is also a cell structure. Secondly, the strength of the wood in the fiber direction is large and not much different from the aluminum alloy cell structure, but the strength in the direction perpendicular to the fiber is small. This indicates that wood has material anisotropy.

  However, when a wooden cushioning material is pierced with a plurality of piercing rods 12 as in the present invention, it should be noted that the difference in performance obtained between the fiber orthogonal direction and the fiber direction is very small as shown in FIGS. 16 (A) and (B). An effect is obtained. In addition, the figure (C) is the data of the aluminum alloy cell structure shown in FIG. 8 taken for comparison. In the system in which the cushioning material 8 is skewered by the plurality of piercing rods 12 as in the present invention, it is considered that the deformation due to the penetration of the rod and the widening deformation in the radial direction can be introduced simultaneously. In either case, a sudden rise in load can be suppressed, and a performance that is substantially equal to or better than that of the aluminum alloy cell structure can be obtained. For the same reason, the same effect can be obtained even when the entry rod 12 enters obliquely with respect to the fiber direction.

  Needless to say, raw wood that is not compressed is included as wood (woody material), but compressed wood may be used, and wood chips hardened with resin, particle boards, etc. are also candidates. enter. The advantages of resin hardened and particle board are that the material anisotropy of wood due to the difference in fiber direction is homogenized by random orientation, and also local fracture (hardness to propagate cracks throughout the material) Is also good. However, if the strength is slightly too high, it is necessary to appropriately adjust the tip shape, tip angle and material of the skewer type skewer.

  It is desirable that the cushioning material 8 formed of wood is subjected to waterproofing or antiseptic treatment, or the entire device including the wooden cushioning material is waterproofed.

  In the above-described configuration, in the embodiment in which the wood rods are oriented in parallel with the wood rod 12 as shown in FIG. 13, when an external force is applied from the state shown in FIG. The wood fibers are plunged into the buffer body 8 while being scraped and crushed. Further, in the embodiment in which the entry rod is oriented perpendicular to the wood fibers as shown in FIG. 14, when an external force is applied from the state shown in FIG. 14 (A), the entry rod 12 as shown in FIG. It rushes into the shock absorber 8 while cutting and crushing. With a soft material such as cypress, even when the rush bar 12 is plunged in a direction perpendicular to the fiber direction, a load close to that when the rush bar 12 is plunged in the fiber direction can be obtained. In particular, the load at the beginning of entry is almost the same.

  In addition, when comparing the case where the rush rod 12 is plunged into the fiber direction of the wood and the case where the plunging rod 12 is rushed into the metal cell structure, the load at the beginning of the rush is almost the same, but the maximum value of the load after that is Wood is bigger. Therefore, in this experimental example, it can be seen that a large amount of momentum can be received by inserting the piercing rod in the fiber direction of the wood.

  Each of the above embodiments is merely a preferred example of the present invention, and the scope of the invention is limited by the numerical values, materials, and other specific matters listed therein, unless they are contrary to the essence of the present invention. It is not something.

1 is an overall configuration diagram of an impact force buffering device according to a first embodiment of the present invention. 2 is a longitudinal section of the device of FIG. 2 is a cross section of the device of FIG. 2 is a cross-sectional view after compression of the apparatus of FIG. It is a figure which shows the example of installation of the apparatus of FIG. It is a graph showing the result of the collision acceleration experiment by the system similar to the apparatus of FIG. 1, and a simple compression system. It is a graph showing the result of the static compression experiment with the buffer material of the apparatus of FIG. 1, and a comparative product. It is a graph which shows the result of having changed the shape of the edge part of the rush bar of the apparatus of FIG. It is an example of a structure of the apparatus used for the test of FIG. It is a figure which shows the state of the test body which applied the impact using the experimental apparatus of FIG. It is a figure which shows the modification of the apparatus of FIG. It is a whole block diagram of the impact-force buffer apparatus which concerns on the 2nd Embodiment of this invention. As a first example of the third embodiment of the present invention, a method of penetrating in a direction parallel to the wood fiber is shown. As a second example of the embodiment, a method of penetrating in a direction orthogonal to the wood fiber is shown. The result of the compression experiment which supports the same embodiment is shown. The result of the impact experiment which supports the embodiment is shown. It is a trace of the microscope picture of the cell structure of wood.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Support stand 4 ... External force receiving part 6 ... Buffer part 8 ... Buffer material 10 ... Buffer unit 12 ... Entry rod 14 ... Tapered end part 16 ... Fixed part 18 ... Cover 20 ... Connecting plate 22 ... Elastic board

Claims (7)

An impact force buffering device that reduces the absolute value of the maximum acceleration at the time of collision by inserting a buffer part between the external force receiving part and the fixed part arranged along the direction of buffering the force and absorbing the impact force,
The cushioning portion 6 is parallel to the force cushioning direction, with the cushioning material 8 arranged with the front and back surfaces facing each other in the force cushioning direction, and at least one end faced to one of the front and back surfaces of the cushioning material. A rush bar 12;
When one of the cushioning material 8 and the rush bar 12 is interlocked with the external force receiving portion 4 and the other is braked in cooperation with the fixing portion 16, an impact force is applied to the external force receiving portion 4. The entry bar 12 is provided so as to strike a part of the front surface or the back surface of the cushioning material 8;
The shock absorbing device is characterized in that the cushioning material 8 is made of a material that can penetrate a plunge rod when the hitting portion is depressed. The cushioning material 8 is formed of a perforated material or a cell structure including at least a hole smaller than the diameter of the entry rod 12, and
2. The impact force buffering device according to claim 1, wherein the impacting shock absorber is provided so that the impacting portion is locally crushed without being broken by the shock absorbing material 8 as a whole.     The impact buffering device according to claim 2, wherein the shock absorbing material 8 has an impact pressure strength of 2 to 60 MPa at a collision speed of 5 to 120 km / hour.   The impact force buffering device according to any one of claims 1 to 3, wherein a tip portion of the penetrating rod 12 for penetrating into the cushioning material 8 is tapered toward the tip. .   As the plunging bar, a plurality of parallel plunging bars are arranged on at least one of the front and back sides of the cushioning material 8, and when an impact force is applied to the external force receiving portion 4, the plurality of the plunging rods are moved from one side to the inside thereof. The impact force buffering device according to any one of claims 1 to 4, wherein the impact rod 12 is provided so as to penetrate therethrough. The shock absorber 6 includes a shock absorber unit 10 comprising a plate-like shock absorber 8 perpendicular to the force shock absorbing direction and a protruding bar portion opposed to the front surface or a part of the back surface of the shock absorber at right angles. It is provided so as to be movable in the buffering direction in tandem with the buffering direction,
Of the series of shock absorbing units, the shock absorbing member 8 or the penetrating rod portion of the first unit is connected to the external force receiving portion 4, and the shock absorbing member 8 or the penetrating rod portion of the last unit is connected to the fixing portion 16, respectively.
When an impact propagates from the external force receiving portion 4 to the fixed portion 16 through each buffer unit 10, reaction force is obtained from an adjacent unit on the fixed portion 16 side in each shock unit, and the rush rod 12 enters the buffer material 8. The impact force buffering device according to any one of claims 1 to 5, wherein the shock absorbing device is made to penetrate. The buffer unit 10 is formed by the buffer material 8 and a plurality of plunging bar portions respectively arranged on both the front surface side and the back surface side of the cushioning material 8, 7. The impact force buffering device according to claim 6, wherein the entry rods 12 are arranged on different axes so that the cross sections of the entry rods on the back side do not overlap.