JP3632441B2 - Guard fence for vehicle - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a vehicle guard fence post that prevents falling from a road and minimizes damage to a driver or a passenger.
[0002]
[Prior art]
The vehicle protection fence is a guide for the driver during normal driving of the vehicle, and prevents the vehicle from falling from the road in the event of an abnormality such as contact or collision, and minimizes damage to the driver and passengers by absorbing collision energy Limit to the limit. The collision energy is absorbed by plastic deformation of the protective fence itself when a certain external force is applied. On the other hand, if the rigid body strength of the protective fence is too large, a vehicle that contacts or collides with the protective fence will be bounced back by the protective fence and spin on the roadway side, possibly causing a secondary disaster.
The protective fence has a structure in which a horizontal beam is bridged between columns that are erected on the road surface at a predetermined interval, and it is required that no obstacle appears on the roadway side from the horizontal beam.
[0003]
The inventors of the present invention have introduced a guard fence post having an aluminum alloy casting having such a basic structure and efficiently absorbing an impact in Japanese Patent Publication No. 57-42764. As shown in FIG. 1, this support column has an S-shaped support column body 1 erected on the road surface with anchor bolts 2. As shown in FIG. 1B showing a bb cross section, the column main body 1 has a substantially H-shaped horizontal cross section, and is provided with a curved concave portion 3 slightly depressed on the road shoulder side at the base.
Mounting seats 55a and 5b on which a plurality of cross beams 4a and 4b are installed are formed on the roadway side of the column main body 1. For example, the top rail 4 a having the cross-sectional shape shown in FIG. 1C is attached to the mounting seat 5 a by the bolt 6. In this way, the protective fence is constructed without an obstacle projecting on the side of the roadway from the lateral beams 4a and 4b (FIG. 1d).
[0004]
[Problems to be solved by the invention]
The guard fence has a shape that tends to warp to the road shoulder side starting from a curved recess 3 formed in the base of the column main body 1. When a vehicle touches or collides with the guard fence, the vehicle usually collides from an oblique direction within 15 degrees, so that the shock is first absorbed by crushing the cross beams 4a and 4b, and then the shock is absorbed by warping and deformation of the column body 1. Is done. As a result, the driver can guide the vehicle along the protective fence without taking a large damage.
1 is made of an aluminum alloy casting. However, as the material of the column main body 1, iron such as tough ductile cast iron may be used. Cast iron has higher mechanical strength than aluminum alloy castings, and also has high resistance to sag as seen in aluminum alloys. Furthermore, cast iron columns are less stretched than aluminum alloy castings.
[0005]
The difference in material means that the shape of FIG. 1 cannot be applied to a cast iron support as it is. If the cast iron support is designed in the shape shown in FIG. 1, the strength of the protective fence is too high, and there is a possibility that the vehicle that has contacted and collided will be bounced back to the roadway. Further, when a force directed toward the road shoulder is applied to the column main body 1 due to an impact at the time of contact / collision, and when the column main body 1 is deformed to the road shoulder side starting from the curved recess 3, a compression force is applied to the road shoulder side flange 7a. In addition, a tensile force is applied to the flange 7b on the roadway side. However, if the material is small in elongation, cracks occur in a part of the flange 7b and the web 7c on the roadway side. Once a crack occurs, the column main body 1 breaks starting from the crack, and the protective fence collapses suddenly on the road shoulder side without exhibiting the original material strength. As a result, a dangerous situation in which the vehicle jumps out of the roadway is caused.
[0006]
[Means for Solving the Problems]
The present invention has been devised to solve such problems. When the column body is made of cast iron, the design taking into account the material of the cast iron minimizes the damage to the driver and passengers. The purpose is to build a vehicle fence that can be used.
In order to achieve the object, the vehicle guard fence post according to the present invention includes a cast iron column main body having a substantially H-shaped horizontal cross section that connects the roadway side flange and the road shoulder side flange with a web. A pedestal part fixed to the protruding anchor bolt is formed in the lower part of the column body, a curved recess is formed in the place where the road shoulder side flange rises from the pedestal part, and in the vertical part of the roadway side flange rising from the pedestal part A plurality of mounting seats for laying the cross beam are provided, and the web connected to the roadway side flange where the greatest tensile force is applied at the time of a vehicle collision at a position higher than the curved recess is a thick part. The wall thickness is in the range of 1.2 to 1.4 times the web thickness without the thick part .
In the height range from the curved concave part to the thick part, it is preferable to make the width of the web excluding the thick part equal.
[0007]
Embodiment
The strut of the guard fence for vehicles according to the present invention is made of cast iron having good toughness such as ductile cast iron and has the shape shown in FIG.
In the column main body 10, a pedestal portion 20 installed on a road surface and a mounting seat 30 to which a cross beam 41 is mounted are integrally formed by casting. There are three (FIG. 2) or two (FIG. 3) column main bodies 10 according to the number of mounting seats 30 attached.
The column main body 10 has a substantially H-shaped horizontal cross section (FIG. 2 c) in which the road shoulder side flange 11 and the roadway side flange 12 are connected by a web 13, and a curved recess 14 is formed in a portion close to the pedestal portion 20. The roadway side flange 12 has a shape that stands vertically from the road surface as shown in FIG.
[0008]
The vertical portion 16 of the roadway side flange 12 is advantageous when the number of mounting seats 30 is set according to needs. For example, a basic structure can be designed using the same wooden mold, and a model can be made by combining splints corresponding to the required number of mounting seats 30, and a mold such as a sand mold can be easily produced.
A part of the web 13 is a thick portion 15. The thick wall portion 15 is set to a location where the largest pulling force is applied to the roadway side flange 12 when the column main body 10 is about to fall to the road shoulder side starting from the curved concave portion 14 due to a vehicle collision. The portion where the thick portion 15 is formed is roughly determined from the material mechanics considering the shape and is determined by a plurality of experiments, but is usually slightly higher than the curved concave portion 14 of the road shoulder side flange 11 at the roadside side. The web 13 is set adjacent to the flange 12. The strength of the column main body 10 is partially increased by the thick-walled portion 15 at the location where cracks and breakage start.
[0009]
The thickness t of the thick portion 15 is preferably in the range of t = (1.2 to 1.4) × t ₀ where the thickness of the web 13 without the thick portion 15 is the reference value t _0. . If the thick portion 15 is too thick, the rigid body strength of the thick portion 15 becomes too high, and an excessive impact is given to a vehicle that contacts or collides. On the contrary, if the thickness t is less than 1.2 × t ₀ , the action of the thick portion 15 is not sufficient, and the roadway side flange 12 is likely to crack.
The shape of the thick portion 15 is preferably determined so that the width w (FIG. 2d) of the web 13 without the thick portion 15 is substantially equal in the vertical direction. By equalizing the width w, the force when the column main body 10 is about to fall to the road shoulder side is equally received by the web 13, and stress concentration at a specific location can be avoided. That is, the impact at the time of vehicle contact / collision is dispersed throughout the web 13 and local breakage of the web 13 is suppressed.
[0010]
The pedestal portion 20 has a seat surface 21 spreading in the horizontal direction, and a bolt insertion hole 22 is formed in the seat surface 21. An anchor bolt 24 fixed to an anchor plate 23 (FIG. 3) embedded in the roadbed protrudes from the road surface, and a bolt insertion hole 22 is fitted to the protruding portion of the anchor bolt 24 so that the seat surface 21 is seated on the road surface and a nut. Tighten with 25. A reinforcing rib 26 extends to the road shoulder flange 11 on the road shoulder side of the seat surface 21.
The mounting seat 30 includes a fitting receiving portion 31 that is curved with a curvature equal to the outer peripheral curvature of the transverse beams 41 to 43 to be installed. Since the vertical portion 16 is formed on the roadway side flange 12, the fitting receiving portion 31 is provided at an appropriate position according to the number of the horizontal beams 41 to 43 without changing the shape of the column main body 10.
A bolt insertion hole 32 is formed in the fitting receiving portion 31. The bolts 33 (FIG. 3) inserted through the bolt insertion holes 32 are inserted into the tube walls of the horizontal beams 41 to 43 and tightened with nuts, so that the horizontal beams 41 to 43 are fixed to the column main body 10 via the fitting receiving portions 31. The
[0011]
The effect | action and effect by having provided the thick part 15 are clear from the result of the strength test demonstrated below.
Ductile cast iron (FCD450-10 defined in JIS G5502) having a thickness of t = 8 mm, a web 13 having a thickness of t ₀ = 6 mm, a width of w = 60 mm, and a height of 80 cm. ) The column main body 10 was installed on the test bed 50 as shown in FIG. A load cell 53 was incorporated into a rod 52 extending from the hydraulic ram 51, and a wire 54 was stretched between the rod 52 and the cross beam 41 fixed to the column body 10. Further, a stand 55 is disposed on the opposite side of the hydraulic ram 51, and a displacement meter 56 provided on the stand 55 is connected to the cross beam 41 by a string 57.
It is assumed that the force that pulls the column main body 10 to the right in FIG. 4 by the hydraulic ram 51 corresponds to the impact force that deforms the column main body 10 at the time of vehicle contact / collision, and the tensile force applied to the column main body 10 and the column main body 10 The relationship with the upper displacement was investigated.
[0012]
FIG. 5 shows the test results when the three column main bodies 10 are pulled. As seen in FIG. In any of the test bodies 1 to 3, even when the upper displacement of the column main body 10 reached 30 cm, the road shoulder side flange 11 cracked and the web 13 buckled in part, but the entire column was broken. I couldn't. Further, the displacement amount-load curve gradually changed until the upper displacement amount reached 30 cm, and a sudden load drop indicating a crack or fracture of the material was not detected. Further, it can be seen that the column has a characteristic that the load corresponding to the upper displacement amount of 30 cm is as large as 30 KN or more and can sufficiently withstand the impact load at the time of vehicle contact / collision.
[0013]
For comparison, a tensile test was performed under the same conditions except that the thick-walled portion 15 was not provided and the column main body 10 having the same shape was used as a test body. In this case, as seen in the test results of FIG. 1 and no. In No. 3, the displacement amount-load curve changed gently. In the test body No. 2, the roadway side flange 12 broke when the upper displacement exceeded 20 cm. This indicates that when the thick portion 15 is not present, the column main body 10 may be broken without exhibiting the original material strength, and is not reliable. Specimen No. 1 and no. 3 means that the load corresponding to the upper displacement amount of 30 cm is about 20 KN, which means that the load is greatly deformed with a relatively small load.
As is clear from this comparison, by forming the thick portion 15 on the web 13 of the column main body 10 having an H-shaped cross section, the strength of the roadway side flange 12 is increased, and it is broken even by an impact received during vehicle contact / collision. The shape is difficult to do. Therefore, the original characteristics of the material are utilized, and damage to the driver or the passenger of the vehicle that has come into contact or collided is minimized.
[0014]
【The invention's effect】
As described above, in the present invention, when using cast iron having a small elongation as compared with an aluminum alloy casting as a column main body, the roadway side flange to which the largest tensile force is applied by the impact of the vehicle contact or collision is provided. Reinforced by the thick part of the web. As a result, struts that utilize the original material strength of cast iron can be obtained, and vehicles that come into contact with or collide with cross beams will not fall from the road, and the impact on the vehicles will be mitigated, minimizing damage to drivers and passengers. It is done. Moreover, since the mounting seat of the cross beam is provided in the vertical part of the roadway side flange rising from the pedestal portion, it can be manufactured using the same mold even when the number of cross beams is changed.
[Brief description of the drawings]
FIG. 1 is a view of an aluminum alloy guard fence post proposed by the present applicant (a), a cross section (b) of the support body, a lateral beam (c) attached to the support post, and a roadway (d) provided with a guard rail.
FIG. 2A is a side view of a column main body according to the present invention, FIG. 2B is a side view of the column main body, FIG. 2C is a cross-sectional view of the column main body, and a lower part of the column main body provided with a curved recess and a thick part. d)
FIG. 3 is a side sectional view of a column installed on the road surface (a) and a view of a guard fence from the roadway side (b).
FIG. 4 is a diagram for explaining a strength test of a column. FIG. 5 is a displacement-load curve diagram of a column main body provided with a thick portion on a web according to the present invention. -Load curve [Explanation of symbols]
10: Prop body 11: Roadside flange 12: Roadside flange 13: Web 14: Curved recess 15: Thick part 16: Vertical part 20: Base part 21: Seat surface 22: Bolt insertion hole 23: Anchor plate 24: Anchor Bolt 25: Nut 26: Rib 30: Mounting seat 31: Fitting receiving part 32: Bolt insertion hole 41-43: Cross beam

Claims (2)

It has a cast iron strut body with a substantially H-shaped horizontal cross section that connects the roadway side flange and the road shoulder side flange with a web, and a pedestal that is fixed to anchor bolts protruding from the road surface is formed at the bottom of the strut body The curved recess is formed at the location where the road shoulder side flange rises from the pedestal, and a plurality of mounting seats are provided to stretch the horizontal beam on the vertical part of the roadway side flange rising from the pedestal, which is higher than the curved recess The web connected to the flange on the roadway where the greatest tensile force is applied at the time of a vehicle collision at the position is a thick portion, and the thickness of the thick portion is 1.2 to 1.1 of the web thickness without the thick portion. A guard fence for vehicles that is 4 times the range . 2. The protective fence post for a vehicle according to claim 1, wherein the width of the web excluding the thick portion is equal in the height range from the curved concave portion to the thick portion.

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