JP4054101B2 - Automotive door reinforcement with excellent energy absorption at the time of collision - Google Patents
Automotive door reinforcement with excellent energy absorption at the time of collision Download PDFInfo
- Publication number
- JP4054101B2 JP4054101B2 JP07869998A JP7869998A JP4054101B2 JP 4054101 B2 JP4054101 B2 JP 4054101B2 JP 07869998 A JP07869998 A JP 07869998A JP 7869998 A JP7869998 A JP 7869998A JP 4054101 B2 JP4054101 B2 JP 4054101B2
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- Prior art keywords
- collision
- door reinforcement
- automobile door
- time
- tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Description
【0001】
【発明の属する技術分野】
本発明は、衝突時の吸収エネルギーに優れた自動車ドア補強材に関するものである。
【0002】
【従来の技術】
周知のごとく、自動車ドア補強材として、衝突時のエネルギーを吸収して安全を確保するため、自動車のドア内に補強材として丸型鋼管または角型鋼管あるいはH型鋼管を装着することが知られている。
【0003】
【発明が解決しようとする課題】
上記のごとく、自動車ドア補強材に丸型鋼管または角型鋼管を用いると、鋼管横断面の偏平変形により荷重負荷量が低下して、吸収エネルギーを低下させることになる。このような現象は、鋼管の板厚(肉厚)が外径に比べて小さくなるに従い、断面の偏平化が早期(荷重負荷量の発生初期)に発生する。即ち、一般に用いられている自動車ドア補強材の試験方法として図6に示すごとく、支点柱1、1a(頂部R12.5)間距離L600mmで、支点柱1、1a上に鋼管2(外径31.8mmの丸型鋼管、降伏応力YS:1200Mpa)を載置し、支点柱1、1a間中央部の鋼管2上からポンチ3のストローク(鋼管への押し込み量)を変化すると、図7に示すごとく鋼管の板厚tが小さくなるほど、横断面の偏平変形が早期(ポンチ3のストローク量が少ないうちに)に発生し、その後の荷重に耐えられない。従って、衝突時の吸収エネルギーを低下させることになる課題がある。また、角型鋼管またはH型鋼管においては、搬送及びドア内への取り付け、熱処理等を施すときに鋼管の外径等に応じた処理が必要になる。従って、コスト、生産性、作業性等において不利である等の課題もある。
【0004】
【課題を解決するための手段】
上記の課題を解決するためになされた本発明は、横断面をほぼ円形とする管の一部に対向する内向きの彎曲縁辺部を形成し、該両彎曲縁辺部と連続一体化して管内に凹部を形成した自動車ドア補強材であって、この凹部の底部を、管の内側直上の、衝突による荷重負荷の発生初期に管の内側と接触して断面形状変化を防止する位置に位置させたことを特徴とするものである。
【0005】
【発明の実施の形態】
本発明者等は、自動車ドア補強材として重負荷時(衝突時)に発生する最高荷重点以降の負荷荷重低下を抑制する形状について、種々検討した結果、最高荷重を抑えかつ、座屈後の耐荷重能力を向上すること、つまり座屈後の形状変化の少ない横断面形状にすることが、高い吸収エネルギーをもつ自動車ドア補強材の条件であることが明らかになった。その形状としては、図1のような横断面形状が最も高い吸収エネルギーをもつ自動車ドア補強材になり得ることを見出した。
この自動車ドア補強材4は、横断面をほぼ円形とする管5の一部に対向する内向きの彎曲縁辺部6、6aを形成する。このような両彎曲縁辺部6、6aと連続一体化して管5内に凹部7を形成する。
上記のごとき凹部7の底部は、管5の内側直上に位置させ若干の間隙を形成するごとく成形することによって、前記のごとく、衝突による座屈後の耐荷重の低下を抑制して、衝突エネルギーを確実に吸収することができるものである。
即ち、本発明の自動車ドア補強材は、図示のごとくaの部位に衝突(曲げ荷重方向)による座屈発生後に、図2のようにbの部位とcの部位とが接触して、衝突による荷重を確実に支え荷重に対して安定な形状となるため座屈後の耐荷重の低下を著しく抑制し、衝突時にエネルギーの吸収を高め安全性を確実に保持することができるものである。
【0006】
このような自動車ドア補強材の材質としては、鋼の他硬質アルミニウム、チタン合金等の非鉄合金等を用いることができるが、コスト的には鋼が最も有利である。鋼を素材とする場合は、車種等によって若干異なるが降伏応力500〜1300Mpa、引張強度600〜1600Mpa、肉厚1.0〜3.0mmで十分である。また、鋼板等の鋼材を用いる場合には、鋼の鋼組織やミクロ組織によらず、前記のごとき形状からなる補強材によれば、確実に衝突時のエネルギーを吸収することのできる自動車ドア補強材となる。更に、鋼板を用いる場合は、例えば熱延鋼板、冷延鋼板を用いることができる。
【0007】
次に、本発明の自動車ドア補強材の一例を挙げる。
図3において、まず、鋼板(帯)を素材として、一般に製造されている例えば電縫鋼管を用い、この横断面鋼管(イ)を成形ロールによって(イ)から順次成形して(ヘ)のごとく成形して自動車ドア補強材とする。
【0008】
【実施例】
次に、本発明の実施例による自動車ドア補強材とともに比較例を挙げる。
実施例1
図4に示す補強材形状
1)サイズ:外径36.0mm、肉厚:2.0mm(a:10mm、b:5mm、c:1mm)。
2)材質:降伏応力YP500Mpa、引張強度TS600Mpa(熱延鋼板)。
【0009】
実施例2
図4に示す補強材形状
1)サイズ:外径36.0mm、肉厚:2.0mm(a:10mm、b:5mm、c:1mm)。
2)材質:降伏応力YP500Mpa、引張強度TS600Mpa(冷延鋼板)。
【0010】
比較例
1)サイズ:外径50.8mm、肉厚:2.0mm丸型鋼管。
2)材質:降伏応力YP500Mpa、引張強度TS600Mpa(熱延鋼板)。
このような本発明の自動車ドア補強材と比較例の丸型鋼管を前記図6に示す試験方法により荷重試験を行ったところ、図5に示すごとくポンチストローク(ポンチ押し込み量)と曲げ荷重は、図示のように、本発明の自動車ドア補強材においては、ポンチ押し込み量が多くなっても大きな曲げ荷重に耐えることができ、衝突時の吸収エネルギーに優れた自動車ドア補強材であることが明らかである。
これに対して、比較例の丸型鋼管は、ポンチ押し込み量が20〜30mmの時点で急速に大きな荷重に耐えられなくなっている。このことは、丸型鋼管のポンチ当接部の横断面方向で大きく偏平変形して座屈が発生し、本発明の自動車ドア補強材に比べ著しく吸収エネルギーが低下していることが明らかである。
【0011】
【発明の効果】
本発明の自動車ドア補強材によれば、衝突時(荷重負荷時)の吸収エネルギーを向上して安全性を高めることができる。また、補強材を薄肉化しても確実に衝突時のエネルギーを吸収ができるので、車体の軽量化を図ることができる。更に補強材の形状によって衝突時のエネルギーを吸収ができるので、高強度金属による補強材を必要とせず、低コストの自動車ドア補強材を提供することができる。更にまた、製造に際しては、通常鋼管製造工程に成形ロール群を連設付加することによって、製造することができ設備的に安価にしかも作業能率を向上し、高い生産性を維持しつつ製造することができる等の優れた効果が得られる。
【図面の簡単な説明】
【図1】本発明による自動車ドア補強材の一例を示す横断面図である。
【図2】本発明による自動車ドア補強材の座屈状態を示す側面図である。
【図3】本発明による自動車ドア補強材の製造方法の一例を示す工程図である。
【図4】本発明による自動車ドア補強材の実施例のサイズを示す横断面図である。
【図5】本発明の実施例による自動車ドア補強材と比較例の自動車ドア補強材曲げ荷重とポンチ押し込み量との関係を示す図表である。
【図6】自動車ドア補強材の試験方法を示す側面図である。
【図7】ポンチ押し込み量と曲げ荷重と試験材板厚との関係を示す図表である。
【符号の説明】
4 自動車ドア補強材
5 管
6 彎曲縁辺部
6a 彎曲縁辺部
7 凹部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automobile door reinforcing material excellent in absorbed energy at the time of a collision.
[0002]
[Prior art]
As is well known, it is known to install a round steel pipe, a square steel pipe or an H-shaped steel pipe as a reinforcing material in an automobile door in order to absorb the energy at the time of collision and ensure safety as an automotive door reinforcing material. ing.
[0003]
[Problems to be solved by the invention]
As described above, when a round steel pipe or a square steel pipe is used for the automobile door reinforcement, the load load is reduced due to the flat deformation of the steel pipe cross section, and the absorbed energy is reduced. Such a phenomenon causes the flattening of the cross section to occur at an early stage (the initial stage of occurrence of the load load) as the plate thickness (thickness) of the steel pipe becomes smaller than the outer diameter. That is, as shown in FIG. 6 as a commonly used test method for automobile door reinforcement, a steel pipe 2 (outer diameter 31) is provided on the
[0004]
[Means for Solving the Problems]
In order to solve the above problems, the present invention forms an inwardly curved edge portion facing a part of a tube having a substantially circular cross section, and is continuously integrated with both the bent edge portions in the tube. A car door reinforcing material having a recess, and the bottom of the recess is positioned immediately above the inside of the pipe at a position where it contacts the inside of the pipe at the initial stage of load generation due to a collision and prevents a change in cross-sectional shape. It is characterized by that.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
As a result of various investigations on the shape that suppresses the load load drop after the maximum load point that occurs during heavy load (collision) as a car door reinforcement, the present inventors have suppressed the maximum load and have been able to It became clear that improving the load-bearing capacity, that is, making the cross-sectional shape with little shape change after buckling, is a condition for automobile door reinforcement with high absorbed energy. As the shape, it found that can be a motor vehicle door reinforcing material having the highest energy absorption is cross-sectional shape as shown in FIG. 1.
The
The bottom of the
That is, the automobile door reinforcement of the present invention is caused by the collision of the part b and the part c as shown in FIG. 2 after the occurrence of buckling due to the collision (bending load direction) at the part a as shown in FIG. Since the load is surely supported and has a stable shape with respect to the load, a decrease in the load resistance after buckling can be remarkably suppressed, energy absorption can be increased during a collision, and safety can be reliably maintained.
[0006]
As a material for such a car door reinforcement, non-ferrous alloys such as hard aluminum and titanium alloy can be used in addition to steel, but steel is most advantageous in terms of cost. When steel is used as a raw material, the yield stress is 500 to 1300 Mpa, the tensile strength is 600 to 1600 Mpa, and the wall thickness is 1.0 to 3.0 mm. In addition, when steel materials such as steel plates are used, automobile door reinforcement that can absorb energy at the time of collision reliably according to the reinforcing material having the shape as described above, regardless of the steel structure or microstructure of steel. Become a material. Furthermore, when using a steel plate, a hot-rolled steel plate and a cold-rolled steel plate can be used, for example.
[0007]
Next, an example of the automobile door reinforcement of the present invention will be given.
In FIG. 3, first, a generally manufactured, for example, ERW steel pipe is used with a steel plate (strip) as a raw material, and this cross-sectional steel pipe (A) is sequentially formed from (A) by a forming roll as shown in (F). Molded into automobile door reinforcement.
[0008]
【Example】
Next, a comparative example is given with the automobile door reinforcement material by the Example of this invention.
Example 1
Reinforcing
2) Material: Yield stress YP500 Mpa, tensile strength TS600 Mpa (hot rolled steel plate).
[0009]
Example 2
Reinforcing
2) Material: Yield stress YP500 Mpa, tensile strength TS600 Mpa (cold rolled steel sheet).
[0010]
Comparative Example 1) Size: outer diameter 50.8 mm, wall thickness: 2.0 mm Round steel pipe.
2) Material: Yield stress YP500 Mpa, tensile strength TS600 Mpa (hot rolled steel plate).
When a load test was performed on the automobile door reinforcing material of the present invention and the round steel pipe of the comparative example by the test method shown in FIG. 6, the punch stroke (punch push-in amount) and the bending load as shown in FIG. As shown in the figure, it is clear that the automobile door reinforcement of the present invention is an automobile door reinforcement that can withstand a large bending load even if the punch push-in amount is large and has excellent absorbed energy at the time of collision. is there.
On the other hand, the round steel pipe of the comparative example cannot quickly withstand a large load when the punch push-in amount is 20 to 30 mm. This clearly shows that buckling occurs due to large flat deformation in the cross-sectional direction of the punch contact portion of the round steel pipe, and it is clear that the absorbed energy is remarkably reduced as compared with the automobile door reinforcement of the present invention. .
[0011]
【The invention's effect】
According to the automobile door reinforcing material of the present invention, the absorbed energy at the time of a collision (at the time of loading) can be improved and safety can be enhanced. In addition, since the energy at the time of collision can be reliably absorbed even if the reinforcing material is thinned, the weight of the vehicle body can be reduced. Further, since the energy at the time of collision can be absorbed by the shape of the reinforcing material, a reinforcing material made of high-strength metal is not required, and a low-cost automobile door reinforcing material can be provided. Furthermore, when manufacturing, it is possible to manufacture by adding a group of forming rolls to the normal steel pipe manufacturing process, which can be manufactured inexpensively while improving work efficiency and maintaining high productivity. It is possible to obtain excellent effects such as
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an automobile door reinforcement according to the present invention.
FIG. 2 is a side view showing a buckled state of the automobile door reinforcement according to the present invention.
FIG. 3 is a process diagram showing an example of a method for manufacturing an automobile door reinforcement according to the present invention.
FIG. 4 is a cross-sectional view showing the size of an embodiment of an automobile door reinforcement according to the present invention.
FIG. 5 is a chart showing the relationship between the automobile door reinforcing material according to an embodiment of the present invention and the comparative example of the automobile door reinforcing material bending load and the punch push-in amount.
FIG. 6 is a side view showing a test method for automobile door reinforcement.
FIG. 7 is a chart showing a relationship among punch indentation amount, bending load, and test material plate thickness.
[Explanation of symbols]
4 Car
Claims (3)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP07869998A JP4054101B2 (en) | 1998-03-26 | 1998-03-26 | Automotive door reinforcement with excellent energy absorption at the time of collision |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP07869998A JP4054101B2 (en) | 1998-03-26 | 1998-03-26 | Automotive door reinforcement with excellent energy absorption at the time of collision |
Publications (2)
Publication Number | Publication Date |
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JPH11278055A JPH11278055A (en) | 1999-10-12 |
JP4054101B2 true JP4054101B2 (en) | 2008-02-27 |
Family
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Application Number | Title | Priority Date | Filing Date |
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JP07869998A Expired - Fee Related JP4054101B2 (en) | 1998-03-26 | 1998-03-26 | Automotive door reinforcement with excellent energy absorption at the time of collision |
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JP (1) | JP4054101B2 (en) |
Families Citing this family (1)
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JP4734129B2 (en) * | 2006-01-23 | 2011-07-27 | 新日本製鐵株式会社 | Automotive strength members with excellent impact characteristics |
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1998
- 1998-03-26 JP JP07869998A patent/JP4054101B2/en not_active Expired - Fee Related
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JPH11278055A (en) | 1999-10-12 |
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