JP6786468B2 - Structural members for vehicles - Google Patents

Description

本発明は、自動車その他の車両の荷重を負担する、閉断面構造の車両用構造部材に係り、特に、２枚の板材から構成された構造部材であって、衝突時の衝突エネルギーを吸収可能な車両用構造部材に関する。 The present invention relates to a structural member for a vehicle having a closed cross-sectional structure that bears the load of an automobile or other vehicle, and in particular, is a structural member composed of two plate members and can absorb collision energy at the time of a collision. Regarding structural members for vehicles.

近年、自動車分野では、環境問題に配慮した燃費向上のための車体軽量化と衝突安全性能の両立を目的として、高強度材の適用が進められている。自動車の衝突安全構造として、車両端部が適度に潰れて変形することで衝撃を吸収し、キャビン周りでは、乗員保護の観点からエネルギー吸収能の高い高強度材が求められる。
このような要望に対し、例えば残留オーステナイトを活用した耐衝突性に優れる鋼板が提案されている（特許文献１）。また部材断面のコーナー部を焼入れ強化した、耐衝突性に優れる鋼板が提案されている（特許文献２）。 In recent years, in the field of automobiles, the application of high-strength materials has been promoted for the purpose of achieving both weight reduction of the vehicle body and collision safety performance for improving fuel efficiency in consideration of environmental problems. As a collision safety structure for automobiles, a high-strength material having high energy absorption capacity is required from the viewpoint of occupant protection, which absorbs impact by appropriately crushing and deforming the end of the vehicle.
In response to such a demand, for example, a steel sheet having excellent collision resistance utilizing retained austenite has been proposed (Patent Document 1). Further, a steel plate having excellent collision resistance in which the corner portion of the cross section of the member is hardened and strengthened has been proposed (Patent Document 2).

このような高強度鋼板を使用した車両用構造部材は、一般に、特許文献１の図５、図６や特許文献２の図３、図６のように、薄板の高強度鋼板をハット形断面にプレス加工したハット形断面鋼板部材を主要部品とする。そして、特許文献１，２のように、そのハット形断面鋼板部材の開口部を塞ぐように第２の鋼板を設け、そのハット形断面鋼板部材の幅方向両側に存在する各フランジ部と第２の鋼板の幅方向端部とをそれぞれスポット溶接にて接合する。このような閉断面形状の構造部材とすることで、衝撃吸収能を具備させている。
このような車両用構造部材は、２つの部材の幅方向端部を、長手方向（軸方向）に沿ってスポット溶接にて接合することで閉断面構造とすることで衝撃吸収能を具備させている。このため、スポット溶接性が要求される。 A vehicle structural member using such a high-strength steel plate generally has a hat-shaped cross section of a thin high-strength steel plate as shown in FIGS. 5 and 6 of Patent Document 1 and FIGS. 3 and 6 of Patent Document 2. The main part is a press-processed hat-shaped cross-section steel plate member. Then, as in Patent Documents 1 and 2, a second steel plate is provided so as to close the opening of the hat-shaped cross-section steel plate member, and each flange portion and the second flange portion existing on both sides of the hat-shaped cross-section steel plate member in the width direction are provided. The widthwise ends of the steel sheets are joined by spot welding. By forming a structural member having such a closed cross-sectional shape, it is provided with an impact absorbing ability.
Such a structural member for a vehicle is provided with an impact absorbing ability by forming a closed cross-sectional structure by joining the widthwise end portions of the two members by spot welding along the longitudinal direction (axial direction). There is. Therefore, spot weldability is required.

しかし、このような車両用構造部材において、ハット形断面鋼板部材の鋼板強度を高める場合には、添加元素の増加を招く。このため、溶接部の硬化によって延性や靱性が低下、あるいは熱影響部の軟化による局所的な応力集中が発生し、接合部において継手強度の低下を招くおそれがある。すなわち、車体軽量化と衝突安全性能（衝撃吸収能）を共に向上させるために、上記のハット形断面鋼板部材を構成する鋼板の高強度化が進むほど、衝突の際の塑性変形に起因する、スポット溶接部を起点とした破断や割れが発生しやすくなって、衝突性能の低下が発生するおそれがある。
これに対し、特許文献３や４には、非溶接の接合として、従来のスポット溶接による接合に替えて接着剤を用いた接合技術が開示されている。 However, in such a structural member for a vehicle, when the steel plate strength of the hat-shaped cross-section steel plate member is increased, the number of additive elements increases. For this reason, the hardening of the welded portion may reduce ductility and toughness, or the softening of the heat-affected zone may cause local stress concentration, resulting in a decrease in joint strength at the joint portion. That is, in order to reduce the weight of the vehicle body and improve the collision safety performance (shock absorption capacity), the higher the strength of the steel plate constituting the hat-shaped cross-section steel plate member, the more the plastic deformation at the time of collision is caused. Breakage or cracking starting from the spot welded portion is likely to occur, which may lead to deterioration of collision performance.
On the other hand, Patent Documents 3 and 4 disclose a joining technique using an adhesive instead of the conventional spot welding joining as a non-welding joining.

特開平１０−２７３７５２号公報Japanese Unexamined Patent Publication No. 10-273752 特許第３３４７９９４号公報Japanese Patent No. 3347994 特開２００５−１９９７４１号公報Japanese Unexamined Patent Publication No. 2005-199741 特開２００５−１９９７４３号公報Japanese Unexamined Patent Publication No. 2005-199743 特開２０１３−１８４１９８号公報Japanese Unexamined Patent Publication No. 2013-184198

車両における衝突安全基準の厳格化に伴い、求められる衝突性能は増加の一途を辿っていることから、構造部材に使用される材料がハイテン化する傾向にある。しかしながら、従来のスポット溶接による接合ではハイテン化による接合部の継手強度低下が、また接着剤による非溶接接合では、接着面の剥離による接合部の破断によって、衝突性能の低下や安定性が課題となる。 With the stricter collision safety standards for vehicles, the required collision performance is steadily increasing, so the materials used for structural members tend to be high-tensile. However, in the conventional spot welding joints, the joint strength of the joints is reduced due to high ten, and in the non-weld joints using adhesives, the joints are broken due to the peeling of the adhesive surface, resulting in a decrease in collision performance and stability. Become.

ここで、特許文献５に、パネル部品間をヘミング加工で接合することが記載されている。しかしながら、特許文献５は、パネル部品間の接合に関する技術であって、車両の荷重を負担する閉断面構造の車両用構造部材への適用について何ら考慮されていない。すなわち、外板であるアウタパネルは外観品質が求められることから、特許文献５に記載は、接合に、スポット溶接ではなく、外観品質が良好なヘミング加工を適用したものであり、衝撃による接合強度が要求される構造部材への適用について考慮されているとは言い難い。特に、特許文献５には、衝突時の衝突エネルギーを吸収可能な車両用構造部材への適用について何ら示唆がされていない。 Here, Patent Document 5 describes that panel parts are joined by hemming. However, Patent Document 5 is a technique relating to joining between panel parts, and does not consider the application of a closed cross-section structure that bears the load of a vehicle to a structural member for a vehicle. That is, since the outer panel, which is an outer panel, is required to have an appearance quality, the description in Patent Document 5 applies not spot welding but hemming processing having good appearance quality to the joint, and the joint strength due to impact is high. It is hard to say that consideration is given to the application to the required structural members. In particular, Patent Document 5 does not suggest any application to structural members for vehicles capable of absorbing collision energy at the time of collision.

本発明は、上記のような点に着目してなされたもので、第１の部材に第２の部材を接合してなる閉断面構造の車両用構造部材であって、衝突時の際の塑性変形に起因する接合部の破断や割れを抑制した衝撃吸収能の高い構造部材を提供することを目的する。 The present invention has been made by paying attention to the above points, and is a structural member for a vehicle having a closed cross-section structure in which a second member is joined to a first member, and plasticity at the time of a collision. It is an object of the present invention to provide a structural member having a high impact absorbing ability, which suppresses breakage and cracking of a joint due to deformation.

課題を解決するために、本発明の一態様の車両用構造部材は、第１の鋼板からなる第１の部材と、第２の鋼板からなる第２の部材とを備え、第１の部材の幅方向両側にある各フランジ部と第２の部材の幅方向端部とを接合する接合部を有することで閉断面形状を形成する車両用構造部材であって、上記第１の鋼板の引張強度は、上記第２の鋼板の引張強度よりも高く、上記接合部の接合構造を、上記第２の部材の幅方向端部を折り曲げ、その折り曲げ部で上記第１の部材のフランジ部を挟み込むヘミング加工部とし、且つ、上記折り曲げ部内において上記フランジ部と上記折り曲げ部内面とを接着剤で接着させた構造としたことを特徴とする。
ここで、第１の部材を構成する第１の鋼板の厚さは、０．８ｍｍ以上３．０ｍｍ以下の範囲が好ましい。 In order to solve the problem, the structural member for a vehicle according to one aspect of the present invention includes a first member made of a first steel plate and a second member made of a second steel plate, and the first member of the first member. A structural member for a vehicle that forms a closed cross-sectional shape by having a joint portion that joins each flange portion on both sides in the width direction and an end portion in the width direction of the second member, and the tensile strength of the first steel plate. Is higher than the tensile strength of the second steel plate, and hemming the joint structure of the joint portion by bending the widthwise end portion of the second member and sandwiching the flange portion of the first member with the bent portion. It is characterized in that it is a processed portion and has a structure in which the flange portion and the inner surface of the bent portion are bonded with an adhesive in the bent portion.
Here, the thickness of the first steel plate constituting the first member is preferably in the range of 0.8 mm or more and 3.0 mm or less.

本発明の一態様によれば、構造部材を構成する鋼板が高強度化することも考慮して、相対的に引張強度が低い第２の部材側の端部を折り曲げることで、閉断面構造を形成する第１の部材と第２の部材との接合部の構造をヘミング加工部で構成し、且つ、上記折り曲げ部内において上記フランジ部と上記折り曲げ部内面とを接着剤で接着させた構造を採用することで、衝突時の塑性変形によって発生する接合部での破断や割れを抑制出来る。
またこのとき、接合部をヘミング加工部とすることで、車両用構造部材に形成される外向きフランジの厚さが増加する。これによって、衝突時の変形箇所の曲げＲが大きくなるため、衝突時に発生するワレ抑制の効果が増大するという効果もある。 According to one aspect of the present invention, in consideration of increasing the strength of the steel plate constituting the structural member, the closed cross-sectional structure is formed by bending the end portion on the side of the second member having a relatively low tensile strength. A structure is adopted in which the structure of the joint portion between the first member and the second member to be formed is composed of a hemming processed portion, and the flange portion and the inner surface of the bent portion are bonded with an adhesive in the bent portion. By doing so, it is possible to suppress breakage and cracking at the joint portion caused by plastic deformation at the time of collision.
Further, at this time, by making the joint portion a hemming processed portion, the thickness of the outward flange formed on the structural member for the vehicle is increased. As a result, the bending R of the deformed portion at the time of collision becomes large, so that there is also an effect that the effect of suppressing cracks generated at the time of collision increases.

さらに、フランジ部と折り曲げ部内面とを接着する接着剤が、接合部補強の役割を果たし、接合部の接合にヘミング加工部を採用しても、衝突の際の衝撃力による部材変形で、接合部が外れることを抑制できる。ここで、発明者らは、ヘミング加工部で接合しただけの接合部の場合、すなわち接着剤を設けない場合は、衝突時の衝撃により、折り曲げ部が開いて接合部で外れることで、衝突性能が低下することがあるという知見を得ている。
以上のように、本発明の一態様によれば、衝突時に発生する接合部の破断や割れを抑制可能な接合部を有した衝撃吸収能の高い車両用構造部材を提供することが可能となる。 Furthermore, the adhesive that adheres the flange and the inner surface of the bent portion plays a role of reinforcing the joint, and even if a hemming processed portion is used to join the joint, the member is deformed due to the impact force at the time of collision. It is possible to prevent the part from coming off. Here, the inventors have found that in the case of a joint portion that is simply joined by a hemming processed portion, that is, in the case where an adhesive is not provided, the bent portion opens due to the impact at the time of collision and comes off at the joint portion. It has been found that may decrease.
As described above, according to one aspect of the present invention, it is possible to provide a structural member for a vehicle having a joint portion capable of suppressing breakage or cracking of the joint portion that occurs at the time of a collision and having a high impact absorbing ability. ..

本発明に基づく実施形態に係る第１の部材と第２の部材との接合前の状態を説明する図である。It is a figure explaining the state before joining of the 1st member and 2nd member which concerns on embodiment based on this invention. 本発明に基づく実施形態に係る車両用構造部材を説明する斜視図である。It is a perspective view explaining the structural member for a vehicle which concerns on embodiment based on this invention. 本発明に基づく実施形態に係る接合部の構成を説明する断面図である。It is sectional drawing explaining the structure of the joint part which concerns on embodiment based on this invention. 接合部の構成の別例を説明する断面図である。It is sectional drawing explaining another example of the structure of a joint part. 接合部の構成の別例を説明する断面図である。It is sectional drawing explaining another example of the structure of a joint part. 実施例における第１の部材の寸法を説明する図である。It is a figure explaining the dimension of the 1st member in an Example. 荷重負荷方向を説明する図である。It is a figure explaining a load load direction. 最大荷重を説明する図である。It is a figure explaining the maximum load. 実施例における衝撃に対する荷重変化を示す図である。It is a figure which shows the load change with respect to the impact in an Example.

次に、本発明の実施形態について図面を参照して説明する。
（構成）
本実施形態の車両用構造部材は、図１に示すように、第１の鋼板からなり且つハット形断面形状の第１の部材１と、第２の鋼板からなり上記第１の部材１の開口部を塞ぐように第１の部材１に沿って配置される第２の部材２とを備える。そして、第１の部材１のフランジ部１Ｃと第２の部材２の幅方向端部２Ａとが接合されることで閉断面構造の部材となっている。第１の部材１の断面形状は、ハット形断面形状以外であっても構わない。第１の部材１と第２の部材２とで閉断面形状が構成可能であれば、本発明を適用することが出来る。 Next, an embodiment of the present invention will be described with reference to the drawings.
(Constitution)
As shown in FIG. 1, the vehicle structural member of the present embodiment is composed of a first member 1 having a hat-shaped cross-sectional shape and made of a first steel plate, and an opening of the first member 1 made of a second steel plate. It includes a second member 2 arranged along the first member 1 so as to close the portion. Then, the flange portion 1C of the first member 1 and the widthwise end portion 2A of the second member 2 are joined to form a member having a closed cross-section structure. The cross-sectional shape of the first member 1 may be other than the hat-shaped cross-sectional shape. The present invention can be applied if a closed cross-sectional shape can be formed by the first member 1 and the second member 2.

そして、本実施形態では、図２に示すように、第１の部材１の幅方向両側に存在する各フランジ部１Ｃと第２の部材２の幅方向端部２Ａとを接合する接合部の接合構造を、相対的に引張強度が低い第２の部材２側の幅方向端部２Ａを折り曲げ、その折り曲げ部２Ｃで、第１の部材１のフランジ部１Ｃを挟み込んだヘミング加工部とし、且つ、図３に示すように、上記折り曲げ部２Ｃ内において、上記フランジ部１Ｃと上記折り曲げ部２Ｃの内面とが接着剤３で接着した構造とした。接着剤３は、熱硬化型樹脂を有する接着剤３であることが好ましい、
第１の鋼板は、例えば引張強度が９８０ＭＰａ以上の高強度材からなり、第１の鋼板の引張強度は、第２の鋼板の引張強度よりも高い。 Then, in the present embodiment, as shown in FIG. 2, a joint portion for joining the flange portions 1C existing on both sides in the width direction of the first member 1 and the width direction end portion 2A of the second member 2 is joined. The structure is such that the widthwise end 2A on the side of the second member 2 having a relatively low tensile strength is bent, and the bent portion 2C sandwiches the flange portion 1C of the first member 1 as a hemming processed portion. As shown in FIG. 3, in the bent portion 2C, the flange portion 1C and the inner surface of the bent portion 2C are bonded with an adhesive 3. The adhesive 3 is preferably an adhesive 3 having a thermosetting resin.
The first steel plate is made of, for example, a high-strength material having a tensile strength of 980 MPa or more, and the tensile strength of the first steel plate is higher than the tensile strength of the second steel plate.

＜第１の部材１＞
第１の部材１は、図１や図２に示すように、高強度鋼板からなるブランク材をハット形断面にプレス加工することで作製されたハット形断面鋼板部材であり、且つ長手方向に延在する構造部材である。第１の部材１は、必ずしも長手方向（軸方向）に直線状に延びている必要はなく、例えば、左右方向に湾曲した形状であっても良いし、長手方向に沿って高さや幅が変化するようなハット形断面形状の部材であっても良い。但し、第１の部材１は、長手方向が想定される衝撃吸収方向に沿って延在した形状の部材であることが好ましい。 <First member 1>
As shown in FIGS. 1 and 2, the first member 1 is a hat-shaped cross-section steel plate member produced by pressing a blank material made of a high-strength steel plate into a hat-shaped cross section, and extends in the longitudinal direction. It is an existing structural member. The first member 1 does not necessarily have to extend linearly in the longitudinal direction (axial direction), and may have a shape curved in the left-right direction, for example, and the height and width change along the longitudinal direction. A member having a hat-shaped cross-sectional shape may be used. However, it is preferable that the first member 1 is a member having a shape extending in the longitudinal direction along the assumed shock absorbing direction.

この第１の部材１は、強度的に車両用構造部材の主要部品をなす。第１の部材１は、天板部１Ａの幅方向両側が、側壁部１Ｂを介してフランジ部１Ｃに連続している。
この第１の部材１となる第１の鋼板は、軽量化と衝突安全性能（衝撃吸収能）の両方を確保するために、引張強度が９８０ＭＰａ以上の高強度材が好ましい。より好ましくは、１１８０Ｍｐａ以上の高強度材である。また、第１の部材１は、例えば厚さが０．８ｍｍ以上３．０ｍｍ以下の範囲の薄鋼板からなる。
このような、高強度材からなり、且つ厚さが上記のような厚さ範囲であれば、想定される衝突時の衝突エネルギーを吸収可能な車両用構造部材を提供可能となる。 The first member 1 is a main component of the structural member for a vehicle in terms of strength. In the first member 1, both sides of the top plate portion 1A in the width direction are continuous with the flange portion 1C via the side wall portion 1B.
The first steel plate to be the first member 1 is preferably a high-strength material having a tensile strength of 980 MPa or more in order to secure both weight reduction and collision safety performance (impact absorption capacity). More preferably, it is a high-strength material of 1180 Mpa or more. Further, the first member 1 is made of, for example, a thin steel plate having a thickness in the range of 0.8 mm or more and 3.0 mm or less.
If it is made of such a high-strength material and the thickness is in the above-mentioned thickness range, it is possible to provide a structural member for a vehicle capable of absorbing the expected collision energy at the time of a collision.

＜第２の部材２＞
第２の部材２は、図１に示すように、ハット形断面を有する第１の部材１の開口部側に配置され、当該第１の部材１の長手方向に沿って延在している。第２の鋼板の幅方向寸法は、第１の部材１の幅方向寸法よりも広い板形状からなる。
第２の部材２は、例えば普通鋼からなり、その厚さが、例えば０．８ｍｍ以上３．０ｍｍ以下の薄鋼板である。 <Second member 2>
As shown in FIG. 1, the second member 2 is arranged on the opening side of the first member 1 having a hat-shaped cross section, and extends along the longitudinal direction of the first member 1. The width direction dimension of the second steel plate has a plate shape wider than the width direction dimension of the first member 1.
The second member 2 is made of, for example, ordinary steel, and is a thin steel plate having a thickness of, for example, 0.8 mm or more and 3.0 mm or less.

＜接合部＞
図１のように、第１の部材１のフランジ部１Ｃの下面（開口部側の面）には、第２の鋼板（第２の部材２）の幅方向端部２Ａが対向して配置される。第２の鋼板の幅方向端部２Ａにおける、第１の部材１のフランジ部１Ｃよりも幅方向に張り出した部分がフランジ部１Ｃ側に折り曲げられることで、図２のような折り曲げ部２Ｃが形成されると共に、その折り曲げ部２Ｃ内にフランジ部１Ｃが挟み込まれて、ヘミング加工部による接合部が形成される（図２参照）。なお、フランジ部１Ｃの全幅が折り曲げ部２Ｃ内に挟み込まれる必要はない。 <Joint>
As shown in FIG. 1, the widthwise end 2A of the second steel plate (second member 2) is arranged to face the lower surface (opening side surface) of the flange portion 1C of the first member 1. To. A bent portion 2C as shown in FIG. 2 is formed by bending a portion of the widthwise end portion 2A of the second steel plate that projects in the width direction from the flange portion 1C of the first member 1 toward the flange portion 1C. At the same time, the flange portion 1C is sandwiched in the bent portion 2C to form a joint portion by the hemming processed portion (see FIG. 2). It is not necessary that the entire width of the flange portion 1C is sandwiched in the bent portion 2C.

折り曲げ部２Ｃ（フランジ部１Ｃを挟み込む部分）の幅方向の長さは、例えば１０ｍｍ以上５０ｍｍ以下である。好ましくは１０ｍｍ以上２０ｍｍ以下である。折り曲げ部２Ｃの長さは、長くするほど外れ難くなるが、その分、車両用構造部材に形成される外向きフランジが大きくなることで、車両用構造部材の質量が重くなり軽量化の点で好ましくない。 The length of the bent portion 2C (the portion sandwiching the flange portion 1C) in the width direction is, for example, 10 mm or more and 50 mm or less. It is preferably 10 mm or more and 20 mm or less. The longer the bent portion 2C is, the more difficult it is to come off. However, the outward flange formed on the vehicle structural member becomes larger by that amount, so that the mass of the vehicle structural member becomes heavier and the weight is reduced. Not preferable.

また本実施形態では、折り曲げ部２Ｃの内面とフランジ部１Ｃとの間が接着剤３で接着されている（図３参照）。接着剤３は、折り曲げ部２Ｃを形成する前に塗布し、ヘミング加工部とした後に硬化させる。
使用する接着剤３としては、エポキシ系やアクリル樹脂系などの樹脂製の硬化型接着剤が好ましい。硬化成分として光硬化成分と熱硬化成分とあるが、接着剤３を折り曲げ部２Ｃ内に塗布し、折り曲げてから硬化させるため、熱硬化成分の方が好ましい。 Further, in the present embodiment, the inner surface of the bent portion 2C and the flange portion 1C are bonded with the adhesive 3 (see FIG. 3). The adhesive 3 is applied before forming the bent portion 2C, formed into a hemmed portion, and then cured.
As the adhesive 3 to be used, a curable adhesive made of a resin such as an epoxy-based adhesive or an acrylic resin-based adhesive is preferable. There are a photo-curing component and a thermosetting component as curing components, but the thermosetting component is preferable because the adhesive 3 is applied into the bent portion 2C and then bent and then cured.

また接着剤３としては、剥離強度が高く且つ耐衝撃用の接着剤を採用することが好ましい。
剥離強度としては、例えば１５００Ｎ／ｍ以上、好ましくは２０００Ｎ／ｍ以上、更に好ましくは５０００Ｎ／ｍ以上である。せん断強度としては、例えば２０ＭＰａ以上、好ましくは３０ＭＰａ以上である。
なお、接着剤３の剥離強度向上のために、接着剤３を塗布して接着する面部分を予め粗面にしておいても良い。 Further, as the adhesive 3, it is preferable to use an adhesive having high peel strength and impact resistance.
The peel strength is, for example, 1500 N / m or more, preferably 2000 N / m or more, and more preferably 5000 N / m or more. The shear strength is, for example, 20 MPa or more, preferably 30 MPa or more.
In addition, in order to improve the peel strength of the adhesive 3, the surface portion to which the adhesive 3 is applied and adhered may be roughened in advance.

（動作その他）
本実施形態における、車両荷重を負担する閉断面形状の車両用構造部材は、荷重を受ける主要部品である第１の部材１用の鋼板（第１の鋼板）としてハイテン材を使用することで、軽量化を図りつつ耐衝撃性を向上させることができる。
この車両用構造部材が、その軸を、車両前後方向に沿った方向で車体に組み込まれ、且つ前面衝突など車両前側に車両前後方向に向かう所定以上の大きさの衝突力が入力された場合を想定する。この場合、車両用構造部材が軸方向に座屈変形することで衝突エネルギーを吸収する。この変形による軸圧壊では、車両用構造部材の断面全周が内側、外側と交互に折り畳まれる、いわゆる蛇腹状に変形が進行することで衝撃を吸収する。 (Operation and others)
In the present embodiment, the vehicle structural member having a closed cross-sectional shape that bears the vehicle load uses a high-tensile steel as the steel plate (first steel plate) for the first member 1 which is the main component that receives the load. Impact resistance can be improved while reducing weight.
When the shaft of this structural member for a vehicle is incorporated into the vehicle body in a direction along the front-rear direction of the vehicle, and a collision force of a predetermined magnitude or more toward the front-rear direction of the vehicle is input to the front side of the vehicle such as a frontal collision. Suppose. In this case, the structural member for the vehicle buckles and deforms in the axial direction to absorb the collision energy. In the shaft crushing due to this deformation, the entire circumference of the cross section of the structural member for the vehicle is folded alternately inside and outside, that is, the deformation progresses in a so-called bellows shape to absorb the impact.

このとき、第１の部材１と第２の部材２とをスポット溶接によって接合した場合には、第１の部材１を構成する第１の鋼板にハイテン材を使用するなど鋼板強度を高めようとすると、第１の鋼板に対する添加元素の増加を招くことから、溶接部の硬化によって延性や靱性が低下、あるいは熱影響部の軟化による局所的な応力集中が発生し、接合部において継手強度の低下を招くおそれがある。すなわち、ハット形断面鋼板部材を構成する第１の部材１を構成する鋼板の高強度化が進むほど、衝突の際の座屈変形による、スポット溶接部を起点とした破断、割れが発生しやすくなって、衝突性能の低下が発生するおそれがある。 At this time, when the first member 1 and the second member 2 are joined by spot welding, the strength of the steel plate is increased by using a high-tensile material for the first steel plate constituting the first member 1. Then, since the number of additive elements to the first steel plate increases, the ductility and toughness decrease due to the hardening of the welded portion, or local stress concentration occurs due to the softening of the heat-affected portion, and the joint strength decreases at the joint portion. May lead to. That is, as the strength of the steel plate constituting the first member 1 constituting the hat-shaped cross-section steel plate member increases, breakage and cracking starting from the spot welded portion due to buckling deformation at the time of collision are likely to occur. As a result, the collision performance may deteriorate.

これに対し、本実施形態では、第１の部材１と第２の部材２の接合部に溶接を採用しないことから、第１の部材１の鋼板強度を高めて、軽量化と耐衝撃性の両方を向上させても、衝突時の際の座屈による塑性変形に伴う、溶接に起因する上記のような接合部の破断や割れを抑制可能となる。
また接着剤だけでの接合では、要求される衝突荷重に対する接着強度が十分とは言えず、接着面の剥離による衝突性能の低下を招くおそれがある。 On the other hand, in the present embodiment, since welding is not adopted at the joint portion between the first member 1 and the second member 2, the steel plate strength of the first member 1 is increased to reduce the weight and impact resistance. Even if both are improved, it is possible to suppress the above-mentioned fracture and cracking of the joint due to welding due to plastic deformation due to buckling at the time of collision.
Further, in the case of joining with only an adhesive, the adhesive strength against the required collision load is not sufficient, and the collision performance may be deteriorated due to the peeling of the adhesive surface.

すなわち、本実施形態では、ハット形断面鋼板部材である第１の部材１と第２の部材２との接合部の構造にヘミング加工部（ヘム構造）とし、且つ、ヘミング加工による折り曲げ部内においてフランジ部と折り曲げ部内面とを接着剤で接着させた構造を採用することで、衝突時の部材変形によって発生する接合部での破断、割れを抑制出来る。
またヘミング加工部を形成する際に、荷重を受ける主要部品である第１の部材１側ではない、第２の部材２側の端部を折り曲げることで、確実にヘミング加工部のための折り曲げを確実に確保しながら、車両用構造部材としての強度が担保される。 That is, in the present embodiment, the structure of the joint portion between the first member 1 and the second member 2 which are the hat-shaped cross-sectional steel plate members is a hemmed portion (hem structure), and the flange is formed in the bent portion by the hemming process. By adopting a structure in which the portion and the inner surface of the bent portion are bonded with an adhesive, it is possible to suppress breakage and cracking at the joint portion caused by deformation of the member at the time of collision.
Further, when forming the hemmed portion, by bending the end portion on the second member 2 side, which is not the first member 1 side, which is the main component that receives the load, the bending for the hemmed portion is surely performed. While ensuring certainty, the strength as a structural member for vehicles is guaranteed.

またこのとき、接合部をヘミング加工部とすることで、車両用構造部材の幅方向に有する外向きフランジの厚さが増加する。これによって、衝突時の変形箇所の曲げＲが大きくなるため、衝突時に発生するワレ抑制の効果が増大するという効果もある。
さらに、フランジ部１Ｃと折り曲げ部２Ｃ内面とを接着する接着剤３は、接合部補強の役割を果たし、接合部の接合にヘミング加工部を採用しても、衝突の際の衝撃力による座屈変形で、接合部が外れることを抑制する。ここで、発明者らは、ヘミング加工部で接合しただけの接合部の場合、すなわち接着剤３を設けない場合は、衝突時の衝撃による座屈変形により、折り曲げ部２Ｃが開いて接合部が外れ、その分、衝突性能が低下するという知見を得ている。 Further, at this time, by making the joint portion a hemming processed portion, the thickness of the outward flange held in the width direction of the structural member for the vehicle is increased. As a result, the bending R of the deformed portion at the time of collision becomes large, so that there is also an effect that the effect of suppressing cracks generated at the time of collision increases.
Further, the adhesive 3 that adheres the flange portion 1C and the inner surface of the bent portion 2C plays a role of reinforcing the joint portion, and even if a hemming processed portion is adopted for joining the joint portion, buckling due to an impact force at the time of collision Suppresses the joint from coming off due to deformation. Here, the inventors have found that in the case of a joint portion simply joined by a hemming processed portion, that is, in the case where the adhesive 3 is not provided, the bent portion 2C is opened due to buckling deformation due to the impact at the time of collision, and the joint portion is opened. It has been found that the collision performance is reduced by that amount.

以上のように、本実施形態によれば、衝突時に発生する接合部の破断、割れを抑制可能な接合部を有した衝撃吸収能の高い車両用構造部材を提供することが可能となる。
なお、上記の車両用構造部材は、例えば、上記の接合部や第１の部材の天板部などが、他の部材と結合して組み付けられる。 As described above, according to the present embodiment, it is possible to provide a structural member for a vehicle having a joint portion capable of suppressing breakage and cracking of the joint portion that occurs at the time of a collision and having a high impact absorbing ability.
The above-mentioned structural member for a vehicle is assembled by combining, for example, the above-mentioned joint portion and the top plate portion of the first member with other members.

（変形例）
ここで、図３では、折り曲げ部２Ｃ内に差し込まれたフランジ部１Ｃの両面に接着剤３が介在する場合を例示しているが、図４に示すように、折り曲げ部２Ｃ内に差し込まれたフランジ部１Ｃの片面側だけに接着剤３を介在させても良い。但し、図３のように両面に接着剤３を設けた方が、接合部補強効果が高い。 (Modification example)
Here, FIG. 3 illustrates a case where the adhesive 3 is interposed on both sides of the flange portion 1C inserted into the bent portion 2C, but as shown in FIG. 4, the adhesive 3 is inserted into the bent portion 2C. The adhesive 3 may be interposed only on one side of the flange portion 1C. However, the effect of reinforcing the joint portion is higher when the adhesive 3 is provided on both sides as shown in FIG.

また、接着剤３の塗布前、又は接着剤３の硬化前に、接合部に対して図５のようなビード１ａ，２ａを形成するプレス加工を施しても良い。ビード形成のプレス加工は、ヘミング加工を行う前でもヘミング加工後であっても良い。この場合、衝突時の部材変形に対し、接合部がより外れにくくなる。 Further, before the adhesive 3 is applied or before the adhesive 3 is cured, the joint may be pressed to form beads 1a and 2a as shown in FIG. The bead forming press working may be performed before or after the hemming process. In this case, the joint portion is more difficult to come off due to the deformation of the member at the time of collision.

次に、本発明に基づき実施例について説明する。
（実施例）
実施形態で説明したもの（図１〜図３参照）と同様な形状に、第１の部材１および第２の部材２で閉断面を形成し、且つ接合部を、ヘミング加工部と接着剤での接着構造とで構成して実施例（表２のＮＯ．１）の車両用構造部材を作製した。 Next, Examples will be described based on the present invention.
(Example)
A closed cross section is formed by the first member 1 and the second member 2 in the same shape as that described in the embodiment (see FIGS. 1 to 3), and the joint portion is formed by a hemming processed portion and an adhesive. The structural member for a vehicle of Example (No. 1 in Table 2) was produced by constructing the adhesive structure of.

図６に第１の部材１の断面寸法を示す。なお、第１の部材１の軸長は２００ｍｍとした。また折り曲げ部２Ｃの幅（フランジ部を挟み込む幅）を１５ｍｍとした。また表１に、第１の部材１および第２の部材２に使用した各鋼板の引張強度（ＴＳ）その他の諸元を示す。 FIG. 6 shows the cross-sectional dimensions of the first member 1. The shaft length of the first member 1 was set to 200 mm. Further, the width of the bent portion 2C (the width of sandwiching the flange portion) was set to 15 mm. Table 1 shows the tensile strength (TS) and other specifications of each steel plate used for the first member 1 and the second member 2.

接着剤３としては、株式会社スリーボンドホールディングス製の高剥離・耐衝撃用接着剤であるThreeBond2249G（液状加熱硬化型エポキシ配合樹脂）を使用した。
接着剤３の塗布位置は、図３と同じ位置である。そして、接着剤３を塗布後し、ヘム構造に加工後、熱処理を施して接着剤３を硬化させた。熱処理条件は、１７０℃×２０分である。 As the adhesive 3, ThreeBond2249G (liquid heat-curable epoxy-blended resin), which is an adhesive for high peeling and impact resistance manufactured by ThreeBond Holdings Co., Ltd., was used.
The coating position of the adhesive 3 is the same as that in FIG. Then, the adhesive 3 was applied, processed into a heme structure, and then heat-treated to cure the adhesive 3. The heat treatment conditions are 170 ° C. × 20 minutes.

（比較例１）
また、第１の部材１のフランジ部１Ｃと第２の部材２の幅方向端部２Ａとを従来と同様にスポット溶接にて接合して接合部を形成した。スポット溶接は４５ｍｍ間隔で実施した。その他は実施例と同様にして比較例１（表２のＮＯ．２）の車両用構造部材を作製した。 (Comparative Example 1)
Further, the flange portion 1C of the first member 1 and the widthwise end portion 2A of the second member 2 were joined by spot welding as in the conventional case to form a joint portion. Spot welding was performed at 45 mm intervals. Other than that, the structural members for vehicles of Comparative Example 1 (No. 2 in Table 2) were produced in the same manner as in Examples.

（比較例２）
接合部に接着剤３を使用しない以外は実施例と同様にして比較例２（表２のＮＯ．３）の車両用構造部材を作製した。
（衝突性能評価）
実施例および各比較例の車両用構造部材に対し、図７のような、所定の衝突速度（１０ｍｍ／ｍｉｎ）で軸方向荷重を負荷したときの最大荷重を測定した。 (Comparative Example 2)
The structural member for a vehicle of Comparative Example 2 (No. 3 in Table 2) was produced in the same manner as in Example except that the adhesive 3 was not used for the joint.
(Collision performance evaluation)
The maximum load when an axial load was applied at a predetermined collision speed (10 mm / min) as shown in FIG. 7 was measured for the vehicle structural members of the examples and each comparative example.

具体的には、図８に示すような荷重―ストローク曲線で評価し、荷重を負荷したときの最初のピーク荷重を最大荷重とした。これは衝撃吸収能を評価するためである。
その評価結果を表２に示す。

Specifically, it was evaluated by a load-stroke curve as shown in FIG. 8, and the first peak load when the load was applied was set as the maximum load. This is to evaluate the shock absorption capacity.
The evaluation results are shown in Table 2.

また、衝撃直後からの車両用構造部材での荷重変化の履歴の例を図９に示す。
表２および図９から分かるように、接合部をヘム構造（ヘミング加工部）だけで構成したＮｏ．３の比較例２では、接合部をスポット溶接で構成したＮｏ．１の比較例１と比較して、同等の最大荷重になっていると共に、平均荷重が高くなっていることから衝撃吸収性が良いことが分かる。 Further, FIG. 9 shows an example of the history of the load change in the structural member for the vehicle immediately after the impact.
As can be seen from Table 2 and FIG. 9, No. 2 in which the joint portion is composed of only a heme structure (hemming processed portion). In Comparative Example 2 of No. 3, No. 3 in which the joint portion was formed by spot welding. Compared with Comparative Example 1 of No. 1, the maximum load is the same and the average load is higher, which indicates that the shock absorption is good.

更に、実施例（Ｎｏ．１）と比較例２（Ｎｏ．３）の評価から分かるように、本発明に基づく発明例では最大荷重および平均荷重ともに大きく向上していることが分かる。すなわち、ヘム構造に対し接着剤３を塗布するだけで、衝突性能が向上していることが分かる。
ここで、上記の実施例及び比較例では、車両用構造部材を構成する第１の部材の引張強度を１２５０ＭＰａで実施した場合であるが、第１の部材の引張強度を９８０ＭＰａに変更して同様の評価をしても、実施例の方が良好であったことを別に確認している。 Further, as can be seen from the evaluations of Example (No. 1) and Comparative Example 2 (No. 3), it can be seen that both the maximum load and the average load are greatly improved in the invention example based on the present invention. That is, it can be seen that the collision performance is improved only by applying the adhesive 3 to the heme structure.
Here, in the above Examples and Comparative Examples, the tensile strength of the first member constituting the structural member for a vehicle is 1250 MPa, but the same applies by changing the tensile strength of the first member to 980 MPa. It was confirmed separately that the examples were better even after the evaluation of.

１ 第１の部材
１Ａ 天板部
１Ｂ 側壁部
１Ｃ フランジ部
２ 第２の部材
２Ａ 幅方向端部
２Ｃ 折り曲げ部
３ 接着剤 1 First member 1A Top plate part 1B Side wall part 1C Flange part 2 Second member 2A Width direction end part 2C Bending part 3 Adhesive

Claims (3)

第１の鋼板からなる第１の部材と、第２の鋼板からなる第２の部材とを備え、第１の部材の幅方向両側にある各フランジ部と第２の部材の幅方向端部とを接合する接合部を有することで閉断面形状を形成する車両用構造部材であって、
上記第１の鋼板の引張強度は、上記第２の鋼板の引張強度よりも高く、
上記接合部の接合構造を、上記第２の部材の幅方向端部を折り曲げ、その折り曲げ部で上記第１の部材のフランジ部を挟み込むヘミング加工部とし、且つ、上記折り曲げ部内において上記フランジ部と上記折り曲げ部内面とを接着剤で接着させた構造とし、
上記接着剤は、少なくとも上記第２の部材における上記折り曲げの位置よりも端部側の部分と、当該折り曲げの位置よりも端部側の部分と対向した上記フランジ部との間に設けられ、
上記ヘミング加工部における上記接着剤が設けられた部分と重なる位置であって、上記第２の部材における上記折り曲げの位置よりも端部側の部分の位置、上記折り曲げの位置よりも端部側の部分と対向した上記フランジ部の位置、及び上記フランジ部に対向した上記第２の部材における上記折り曲げの位置よりも内側の部分の位置に、ビードが形成されている、
ことを特徴とする車両用構造部材。 A first member made of a first steel plate, a second member made of a second steel plate, each flange portion on both sides in the width direction of the first member, and a widthwise end portion of the second member. It is a structural member for a vehicle that forms a closed cross-sectional shape by having a joint portion for joining.
The tensile strength of the first steel sheet is higher than the tensile strength of the second steel sheet.
The joint structure of the joint portion is a hemming processed portion in which the widthwise end portion of the second member is bent and the flange portion of the first member is sandwiched between the bent portions, and the flange portion is formed in the bent portion. The structure is such that the inner surface of the bent portion is bonded with an adhesive.
The adhesive is provided between at least a portion of the second member on the end side of the bent position and a flange portion facing the end side of the bent position.
The position of the hemming processed portion that overlaps with the portion where the adhesive is provided, the position of the portion of the second member on the end side of the bending position, and the position of the end side of the bending position. Beads are formed at the position of the flange portion facing the portion and at the position of the portion inside the bending position of the second member facing the flange portion .
A structural member for a vehicle, characterized in that. 上記接着剤は、熱硬化型樹脂を有することを特徴とする請求項１に記載した車両用構造部材。 The vehicle structural member according to claim 1, wherein the adhesive has a thermosetting resin. 上記第１の鋼板は、引張強度が９８０ＭＰａ以上の高強度材からなることを特徴とする請求項１又は請求項２に記載した車両用構造部材。 The vehicle structural member according to claim 1 or 2, wherein the first steel plate is made of a high-strength material having a tensile strength of 980 MPa or more.

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