JP3611885B2

JP3611885B2 - Shock absorbing steering column and manufacturing method thereof

Info

Publication number: JP3611885B2
Application number: JP30989794A
Authority: JP
Inventors: 進今垣; 博美磯川; 周三平櫛
Original assignee: Koyo Seiko Co Ltd
Current assignee: Koyo Seiko Co Ltd
Priority date: 1994-11-18
Filing date: 1994-11-18
Publication date: 2005-01-19
Anticipated expiration: 2020-01-19
Also published as: JPH08142877A

Description

【０００１】
【産業上の利用分野】
本発明は、車両の衝突時において運転者に作用する衝撃を吸収するために用いられる衝撃吸収式ステアリングコラムとその製造方法に関する。
【０００２】
【従来の技術】
筒状の第１コラムに筒状の第２コラムを筒状のスペーサを介し圧入し、両コラムの軸方向相対移動によって衝撃エネルギーを吸収するようにした衝撃吸収式ステアリングコラムが提案されている（実開平１‐１７２９６５号公報参照）。そのスペーサにより両コラムが互いにこじれるのを防止し、両コラムの円滑な軸方向相対移動により衝撃エネルギーの吸収を図るものである。従来、そのスペーサの内周および外周は平坦な円筒面とされている。
【０００３】
【発明が解決しようとする課題】
上記構成の衝撃吸収式ステアリングコラムにおいては、第１コラムへの第２コラムのスペーサを介する圧入荷重が過大になると、両コラムの軸方向相対移動に要する荷重も過大になる。一方、その圧入荷重が小さくなり過ぎると、両コラムの軸方向相対移動に要する荷重も小さくなり過ぎる。すなわち、両コラムの軸方向相対移動に要する荷重を適正な範囲に設定することができなければ、大きな衝撃が運転者に作用してしまう。
【０００４】
そこで、両コラムとスペーサとの間の締めしろを管理することで、その両コラムの軸方向相対移動に要する荷重を適正範囲内に設定することが行なわれる。すなわち、図１４に示すように、第１コラムの内径から第２コラムの外径を差し引いた値を２で割ることで得られる両コラムの間の隙間寸法をＤ１、そのスペーサの圧入前の全厚み寸法をＤ２とする場合、その全厚み寸法と隙間寸法との差Ｄ２−Ｄ１に応じ圧入荷重が変化することから、その差Ｄ２−Ｄ１を管理することで、その両コラムの軸方向相対移動に要する荷重を適正範囲内に設定できる。
【０００５】
しかし、第１コラムの内径寸法、第２コラムの外径寸法およびスペーサの圧入前の全厚み寸法は、一定以上の加工公差が必要である。その公差に応じ、両コラムの間の隙間寸法Ｄ１およびスペーサの圧入前の全厚み寸法Ｄ２はばらつく。例えば、図１３における実線は、従来のスペーサの圧入前の全厚み寸法Ｄ２が一定であるとした場合における、両コラムの間の隙間寸法Ｄ１の設定値からのばらつきと軸方向相対移動に要する荷重との関係を示し、両コラムの間の隙間寸法Ｄ１は公差範囲±δ（例えば±０．０２５ｍｍ程度）でばらつき、そのばらつきに応じ荷重がばらつくのを確認できる。これは、図１４に示すように、両コラムの間の隙間寸法Ｄ１が±δの範囲でばらつく場合、そのばらつきに応じスペーサの圧入時の圧縮変形量が変動するためである。その荷重のばらつきは、実際にはスペーサの全厚み寸法もばらつくため、図１３に示すよりも大きくなる。特に、そのスペーサを合成樹脂材により型成形する場合、成形誤差が大きくなるため、その荷重を適正範囲内に設定することは困難であった。
【０００６】
本発明は、上記従来技術の問題を解決することのできる衝撃吸収式ステアリングコラムとその製造方法を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本件第１発明は、筒状の第１コラムに筒状の第２コラムが筒状のスペーサを介し圧入されている衝撃吸収式ステアリングコラムにおいて、そのスペーサは、合成樹脂材により形成されると共に外周および内周のうちの少なくとも一方に形成される複数の突条を有し、その第１コラムの内周および第２コラムの外周のうちの少なくとも一方は、それら突条を介しスペーサに接し、その突条を除けばスペーサの外周は第１コラムの内周に沿うと共にスペーサの内周は第２コラムの外周に沿うものとされ、両コラム間に圧入されているスペーサの突条の高さ寸法は、その突条を除いた部分の厚み寸法よりも小さくされ、そのスペーサの圧入前における突条を除いた部分の厚み寸法と突条の高さ寸法の和である全厚み寸法は、両コラム間の隙間寸法よりも大きくされ、そのスペーサの圧入前の全厚み寸法から突条の高さ寸法を差し引いた寸法は、両コラム間の隙間寸法よりも小さくされ、両コラムのスペーサを介する圧入状態では第１コラムの内周と第２コラムの外周とにより突条は圧縮変形されていることを特徴とする。
【０００８】
本件第２発明は、本件第１発明の衝撃吸収式ステアリングコラムを製造するに際し、そのスペーサの圧入前における突条を除いた部分の厚み寸法と突条の高さ寸法の和である全厚み寸法を両コラムの間の隙間寸法よりも大きくし、そのスペーサの圧入前の全厚み寸法から突条の高さ寸法を差し引いた寸法を両コラムの間の隙間寸法よりも小さくし、各突条を圧縮変形させつつ第１コラムに第２コラムをスペーサを介し圧入することを特徴とする。
【０００９】
【発明の作用および効果】
本件発明によれば、両コラムとスペーサとの間の締めしろを管理することで、両コラムの軸方向相対移動に要する荷重を適正範囲内に設定することができる。すなわち、図１２に示すように、第１コラムの内径から第２コラムの外径を差し引いた値を２で割ることで得られる両コラムの間の隙間寸法をＤ１、そのスペーサの圧入前の全厚み寸法をＤ２とする場合、その全厚み寸法と隙間寸法との差Ｄ２−Ｄ１に応じ圧入荷重が変化し、その圧入荷重は両コラムの軸方向相対移動に要する荷重に対応する。その両コラムの軸方向相対移動に要する荷重のばらつきは、その第１コラムの内径寸法、第２コラムの外径寸法およびスペーサの圧入前の全厚み寸法の加工公差に応じ、両コラムの間の隙間寸法Ｄ１およびスペーサの圧入前の全厚み寸法Ｄ２がばらついたとしても、従来よりも小さくできる。これは、図１２に示すように、そのスペーサの圧入前の全厚み寸法Ｄ２を両コラムの間の隙間寸法Ｄ１よりも大きくし、そのスペーサの圧入前の全厚み寸法Ｄ２から突条３ｄの高さ寸法Ｈを差し引いた寸法Ｄ３を両コラムの間の隙間寸法Ｄ１よりも小さくすることで、スペーサの圧入時の圧縮変形量が従来よりも小さくなることによる。すなわち、両コラムの間の隙間寸法Ｄ１が±δの公差範囲でばらついたとしても、そのばらつきによるスペーサの圧入時の圧縮変形量の変動は、従来のようにスペーサの内外周が平坦な円筒面である場合よりも小さくなる。これにより、両コラムの軸方向相対移動に要する荷重を適正範囲内に設定し、適正に衝撃エネルギーを吸収することができる。なお、スペーサの圧入前の全厚み寸法Ｄ２がばらついたとしても、Ｄ２＞Ｄ１＞Ｄ３の関係が成立して適正に衝撃エネルギーを吸収できるように、スペーサの圧入前の全厚み寸法Ｄ２および突条３ｄの高さ寸法Ｈは設定される。
【００１０】
両コラム間に圧入されている状態でのスペーサの突条の高さ寸法を、突条の形成されていない部分の厚み寸法よりも小さくすることで、そのスペーサが合成樹脂材製で金属等に比べ変形し易いものであっても、衝撃作用時における突条の変形による両コラムの相対的な傾きを小さくし、また、その突条の形成されていない変形し難い部分により両コラムを軸方向相対移動するように案内できるので、両コラムを円滑に軸方向相対移動させて適正に衝撃エネルギーを吸収できる。
【００１１】
【実施例】
以下、図面を参照して本発明の実施例を説明する。
【００１２】
図１〜図６に示す衝撃吸収式ステアリングコラム１は、筒状の金属製第１コラム２ａと、この第１コラム２ａに筒状のスペーサ３を介し圧入される金属製第２コラム２ｂとを備える。その第１コラム２ａは、ベアリング４を介し筒状の第１ハンドルシャフト５を支持する。その第１ハンドルシャフト５の一端にステアリングホイール（図示省略）が連結され、他端に第２ハンドルシャフト７の一端が挿入され、その第２ハンドルシャフト７はベアリング６を介し第２コラム２ｂにより支持される。そのベアリング４は、第１コラム２ａの内周に形成された段差と第１ハンドルシャフト５の外周に取り付けられた止め輪１２とにより、第１コラム２ａと第１ハンドルシャフト５とに対する軸方向相対移動が規制される。
【００１３】
図２に示すように、その第２ハンドルシャフト７の外周に一対の周溝８が形成され、その周溝８に連通する通孔９が第１ハンドルシャフト５に形成され、その通孔９と周溝８とに樹脂６０が充填される。衝撃が作用すると、その樹脂６０が破断され、第１ハンドルシャフト５と第２ハンドルシャフト７とは軸方向相対移動する。第１ハンドルシャフト５の内周形状と第２ハンドルシャフト７の外周形状とは非円形とされることで、第１ハンドルシャフト５と第２ハンドルシャフト７とは回転伝達可能に連結されている。
【００１４】
その第１コラム２ａにアッパーブラケット１１が溶接されている。そのアッパーブラケット１１は、図３、図４、図５（１）に示すように、第１コラム２ａの径方向外方に延び出る一対の支持部１１ａを有する。各支持部１１ａの一端から第１コラム２ａの軸方向に直角に延び出る側壁部１１ｄと、各側壁部１１ｄの一端から第１コラム２ａの軸方向に平行に延び出る突出部１１ｅとを有する。各支持部１１ａに、ステアリングホイール側において開口する切欠１１ｂが形成されている。各切欠１１ｂに連結部材２０が挿入されている。図５の（２）に示すように、各連結部材２０は、各切欠１１ｂの内面に入り込む上部２０ａと、各切欠１１ｂの周囲の下面に沿う下部２０ｂとを有する。各支持部１１ａの切欠１１ｂの周縁に沿う部分に複数の通孔が形成され、各通孔に通じる通孔２０ｃが連結部材２０の下部２０ｂに形成され、それら通孔に合成樹脂製のピン６１が挿通される。各ピン６１は、各切欠１１ｂの周囲の上面に沿う保持部材６１′に一体化されている。各連結部材２０と各保持部材６１′の上面に、板金製プレート６３が沿わせられ、そのプレート６３と各連結部材２０に形成される通孔６３′、２０′に、車体側部材４５に植え込まれるネジ軸４０が挿通される。そのネジ軸４０にねじ合わされるナット４１と車体側部材４５とで、そのプレート６３と保持部材６１′と支持部１１ａと連結部材２０とが挟み込まれる。なお、そのプレート６３と連結部材２０の通孔６３′、２０′は、コラム軸方向が長手方向の長孔とされ、製作誤差による各部材相互の位置ずれに対応可能とされている。衝撃が作用すると、そのピン６１が破断され、そのアッパーブラケット１１は第１コラム２ａと共にプレート６３と保持部材６１′と連結部材２０とに対し相対移動する。
【００１５】
各プレート６３は、保持部材６１′と車体側部材４５とで挟み込まれる上部６３ａと、その上部６３ａの一端から第１コラム２ａの軸方向に直角に延び出る中間部６３ｂと、その中間部６３ｂの一端から第１コラム２ａの軸方向に平行に延び出る下部６３ｃとを有する。各中間部６３ｂはアッパーブラケット１１の各支持部１１ａに形成される開口１１ｆに挿入されると共に各側壁部１１ｄに沿い、各下部６３ｃは突出部１１ｅに沿う。各下部６３ｃと突出部１１ｅとにリング６４が嵌合される。これにより、衝撃が作用してアッパーブラケット１１がプレート６３に対し相対移動すると、そのアッパーブラケット１１の開口１１ｆの内面によりプレート６３の中間部６３ｂが押され、図６に示すように、プレート６３が塑性変形する。
【００１６】
図１に示すように、その第２コラム２ｂにロアブラケット１０が溶接され、そのロアブラケット１０を介し第２コラム２ｂは車体に取り付けられる。
【００１７】
図７、図８の（１）、（２）に示すように、前記スペーサ３は例えばナイロン等の合成樹脂材により円筒形に型成形され、軸方向に沿う割り溝３ａを有することで径方向に弾性変形可能とされ、また、一端に内向きに突出するフランジ３ｂを有する。そのフランジ３ｂは第２コラム２ｂの端面に接する。そのスペーサ３は、その外周の周方向に間隔をおいた複数の領域に、軸方向に沿って形成された複数の突条３ｄを有する。その突条３ｄの形成されていない外周領域３ｅは平坦な円筒面とされている。これにより、第１コラム２ａの内周面は各突条３ｄを介しスペーサ３に接する。図８の（３）に示すように、両コラム２ａ、２ｂ間に圧入された状態でのスペーサ３の突条３ｄの高さ寸法ｈは、突条３ｄの形成されていない部分３ｆの厚み寸法Ｄ３よりも小さくされている。
【００１８】
図１２に示すように、そのスペーサ３の圧入前の全厚み寸法Ｄ２は両コラム２ａ、２ｂの間の隙間寸法Ｄ１よりも大きく、そのスペーサ３の圧入前の全厚み寸法Ｄ２から突条の高さ寸法Ｈを差し引いた寸法Ｄ３は両コラム２ａ、２ｂの間の隙間寸法Ｄ１よりも小さくされる。その圧入前のスペーサ３は第２コラム２ｂの外周に嵌合され、その一端のフランジ３ｂは第２コラム２ｂの端面に当接される。そのスペーサ３の外周に第１コラム２ａが圧入され、その圧入の際に各突条３ｄが圧縮変形される。なお、スペーサ３の圧入前の全厚み寸法Ｄ２がばらついたとしても、Ｄ２＞Ｄ１＞Ｄ３の関係が成立して適正に衝撃エネルギーを吸収できるように、スペーサ３の圧入前の全厚み寸法Ｄ２および突条３ｄの高さ寸法Ｈが設定される。
【００１９】
上記構成において、車両の衝突により衝撃力が作用すると、樹脂６０、６１が剪断されて衝撃エネルギーが吸収され、両コラム２ａ、２ｂが軸方向相対移動することによってプレート６３が塑性変形することで衝撃エネルギーが吸収され、両コラム２ａ、２ｂを軸方向相対移動させるのに要する荷重に応じた衝撃エネルギーが吸収される。
【００２０】
上記実施例によれば、スペーサ３の圧入前の全厚み寸法Ｄ２は両コラム２ａ、２ｂの間の隙間寸法Ｄ１よりも大きく、そのスペーサ３の圧入前の全厚み寸法Ｄ２から突条３ｄの高さ寸法Ｈを差し引いた寸法Ｄ３は両コラム２ａ、２ｂの間の隙間寸法Ｄ１よりも小さいので、スペーサ３の圧入時における圧縮変形量は、従来のようにスペーサの内外周が平坦な円筒面である場合よりも小さくなる。これにより、加工公差に応じ両コラム２ａ、２ｂの間の隙間寸法Ｄ１およびスペーサ３の圧入前の全厚み寸法Ｄ２がばらついたとしても、そのばらつきによるスペーサ３の圧入時の圧縮変形量の変動は従来より小さくなり、その圧入荷重に対応する両コラム２ａ、２ｂの軸方向相対移動に要する荷重のばらつきも従来より小さくできる。図１３における２点鎖線は、上記実施例のスペーサ３の圧入前の全厚み寸法Ｄ２が一定であるとした場合における、両コラム２ａ、２ｂ間の隙間寸法Ｄ１の設定値からのばらつきと軸方向相対移動に要する荷重との関係を示し、その隙間寸法Ｄ１のばらつきに対する荷重のばらつきは、実線で示した従来のスペーサの荷重のばらつきよりも小さくなるのを確認できる。これにより、両コラム２ａ、２ｂの軸方向相対移動に要する荷重を適正範囲内に設定し、適正に衝撃エネルギーを吸収できる。
【００２１】
また、両コラム２ａ、２ｂ間に圧入されている状態でのスペーサ３の突条３ｄの高さ寸法ｈを、突条３ｄの形成されていない部分３ｆの厚み寸法Ｄ３よりも小さくすることで、そのスペーサ３が合成樹脂材製で金属等に比べ変形し易いものであっても、衝撃作用時における突条３ｄの変形による両コラム２ａ、２ｂの相対的な傾きを小さくし、また、その突条３ｄの形成されていない変形し難い部分３ｆにより両コラム２ａ、２ｂを軸方向相対移動するように案内できるので、両コラム２ａ、２ｂを円滑に軸方向相対移動させて適正に衝撃エネルギーを吸収できる。
【００２２】
なお、本発明は上記実施例に限定されない。例えば、上記実施例ではスペーサ３を円筒形状としたが、図９に示すように、円筒形の一端において開口する複数の切欠３ｇを有する形状とし、その切欠３ｇを除く外周全域に突条３ｄを設けてもよい。また、上記実施例では円筒形のスペーサ３の外周の周方向に間隔をおいた複数の領域に突条３ｄを形成したが、図１０に示すように、外周の全領域に突条３ｄを形成してもよい。なお、この場合はスペーサ３の圧入時の圧縮変形量は従来よりは少ないが上記実施例よりも多くなるため、図１３において破線で示すように、両コラム２ａ、２ｂ間の隙間寸法Ｄ１の設定値からのばらつきに対する両コラム２ａ、２ｂの軸方向相対移動に要する荷重のばらつきは、実線で示した従来のスペーサよりも小さくなるが、上記実施例よりは大きくなる。また、上記実施例ではスペーサ３の一端から内向きに突出するフランジ３ｂを第２コラム２ｂの端面に当接させたが、図１１に示すように、スペーサ３の一端から外向きに突出するフランジ３ｈを第１コラム２ａの端面に当接させてもよく、この場合、突条はスペーサ３の内周に設ける。また、スペーサ３の内周と外周の両方に突条を設けてもよい。また、上記実施例ではスペーサ３の軸方向に沿って突条３ｄを設けたが、スペーサの周方向に沿って突条を設けてもよい。また、上記実施例ではスペーサ３の突条３ｄの断面形状が略三角形のものについて説明したが、その断面形状を略台形としてもよい。
【図面の簡単な説明】
【図１】本発明の実施例のステアリングコラムの断面図
【図２】そのステアリングコラムの部分断面図
【図３】そのステアリングコラムの部分側面図
【図４】そのステアリングコラムの部分平面図
【図５】そのステアリングコラムの（１）は部分断面図、（２）は連結部材と保持部材の斜視図
【図６】そのステアリングコラムの衝撃作用後の側面図
【図７】そのステアリングコラムのスペーサの斜視図
【図８】そのスペーサの（１）は縦断面図、（２）は横断面図、（３）は両コラム間への圧入状態での部分断面図
【図９】本発明の変形例のスペーサの斜視図
【図１０】本発明の変形例のスペーサの斜視図
【図１１】本発明の変形例のステアリングコラムの部分断面図
【図１２】本発明のステアリングコラムの作用説明図
【図１３】両コラム間の隙間のばらつきと両コラムを軸方向相対移動させるのに要する荷重との関係を示す図
【図１４】従来のステアリングコラムの作用説明図
【符号の説明】
２ａ第１コラム
２ｂ第２コラム
３スペーサ
３ｄ突条[0001]
[Industrial application fields]
The present invention relates to an impact absorption type steering column used for absorbing an impact acting on a driver at the time of a vehicle collision and a method for manufacturing the same.
[0002]
[Prior art]
An impact-absorbing steering column has been proposed in which a cylindrical second column is press-fitted into a cylindrical first column via a cylindrical spacer, and the impact energy is absorbed by the axial relative movement of both columns ( (See Japanese Utility Model Publication No. 1-172965). The spacers prevent the columns from being twisted with each other, and the impact energy is absorbed by the smooth axial relative movement of the columns. Conventionally, the inner periphery and the outer periphery of the spacer are flat cylindrical surfaces.
[0003]
[Problems to be solved by the invention]
In the shock absorbing steering column having the above-described configuration, when the press-fit load through the spacer of the second column to the first column becomes excessive, the load required for the relative movement of both columns in the axial direction also becomes excessive. On the other hand, if the press-fitting load becomes too small, the load required for the axial relative movement of both columns also becomes too small. That is, if the load required for the relative movement of both columns in the axial direction cannot be set within an appropriate range, a large impact will act on the driver.
[0004]
Therefore, by managing the interference between the two columns and the spacer, the load required for the axial relative movement of the two columns is set within an appropriate range. That is, as shown in FIG. 14, the gap dimension between both columns obtained by dividing the value obtained by subtracting the outer diameter of the second column from the inner diameter of the first column by 2 is D1, and the total of the spacers before press-fitting of the spacers. When the thickness dimension is D2, the press-fitting load changes in accordance with the difference D2-D1 between the total thickness dimension and the gap dimension. By managing the difference D2-D1, the relative movement in the axial direction of the two columns is achieved. Can be set within an appropriate range.
[0005]
However, the inner diameter dimension of the first column, the outer diameter dimension of the second column, and the total thickness dimension before press-fitting the spacer need to have a certain processing tolerance. Depending on the tolerance, the gap dimension D1 between both columns and the total thickness dimension D2 before press-fitting of the spacer vary. For example, the solid line in FIG. 13 shows the variation from the set value of the gap dimension D1 between the columns and the load required for the axial relative movement when the total thickness dimension D2 before press-fitting of the conventional spacer is constant. The gap dimension D1 between both columns varies within a tolerance range ± δ (for example, about ± 0.025 mm), and it can be confirmed that the load varies according to the variation. This is because, as shown in FIG. 14, when the gap dimension D1 between both columns varies within a range of ± δ, the amount of compressive deformation at the time of press-fitting of the spacers varies according to the variation. The variation in the load is actually larger than that shown in FIG. 13 because the total thickness of the spacer varies. In particular, when the spacer is die-molded with a synthetic resin material, a molding error increases, and it is difficult to set the load within an appropriate range.
[0006]
An object of the present invention is to provide an impact-absorbing steering column that can solve the above-described problems of the prior art and a method for manufacturing the same.
[0007]
[Means for Solving the Problems]
The first aspect of the present invention is an impact absorption type steering column in which a cylindrical second column is press-fitted into a cylindrical first column via a cylindrical spacer. The spacer is formed of a synthetic resin material and has an outer periphery. And a plurality of ridges formed on at least one of the inner circumferences, at least one of the inner circumference of the first column and the outer circumference of the second column is in contact with the spacer via the ridges, and Except for the ridges, the outer circumference of the spacer is along the inner circumference of the first column and the inner circumference of the spacer is along the outer circumference of the second column. The height dimension of the ridge of the spacer press-fitted between both columns Is smaller than the thickness dimension of the portion excluding the ridge, and the total thickness dimension, which is the sum of the thickness dimension of the portion excluding the ridge and the height dimension of the ridge before press-fitting the spacer, The gap dimension between The dimension obtained by subtracting the height dimension of the ridge from the total thickness dimension before press-fitting of the spacer is made smaller than the gap dimension between both columns, and in the press-fitted state via the spacers of both columns, The protrusion is compressed and deformed by the inner periphery and the outer periphery of the second column .
[0008]
In the second invention of the present invention, when manufacturing the shock absorbing steering column of the first invention of the present invention , the total thickness dimension which is the sum of the thickness dimension of the portion excluding the protrusion and the height dimension of the protrusion before the spacer is press-fitted. Is larger than the gap between the two columns, and the dimension obtained by subtracting the height of the ridge from the total thickness of the spacer before press fitting is made smaller than the gap between the two columns. The second column is press-fitted into the first column through a spacer while being compressed and deformed.
[0009]
Operation and effect of the invention
According to the present invention, by managing the interference between the two columns and the spacer, it is possible to set the load required for the relative movement of the two columns in the axial direction within an appropriate range. That is, as shown in FIG. 12, the dimension of the gap between the two columns obtained by dividing the value obtained by subtracting the outer diameter of the second column from the inner diameter of the first column by 2 is D1, and the total size before press-fitting the spacer When the thickness dimension is D2, the press-fit load changes according to the difference D2-D1 between the total thickness dimension and the gap dimension, and the press-fit load corresponds to the load required for the relative movement in the axial direction of both columns. The variation in the load required for the axial relative movement of the two columns depends on the machining tolerances of the inner diameter of the first column, the outer diameter of the second column, and the total thickness of the spacer before press-fitting the spacer. Even if the gap dimension D1 and the total thickness dimension D2 before the press-fitting of the spacer vary, it can be made smaller than before. As shown in FIG. 12, the total thickness dimension D2 before press-fitting of the spacer is made larger than the gap dimension D1 between both columns, and the height of the protrusion 3d is increased from the total thickness dimension D2 before press-fitting of the spacer. This is because the amount of compressive deformation at the time of press-fitting of the spacer becomes smaller than the conventional one by making the dimension D3 obtained by subtracting the dimension H smaller than the gap dimension D1 between both columns. That is, even if the gap dimension D1 between the two columns varies within a tolerance range of ± δ, the variation in the amount of compressive deformation during the press-fitting of the spacer due to the variation is a cylindrical surface where the inner and outer circumferences of the spacer are flat as in the prior art. It becomes smaller than the case. Thereby, the load required for the axial relative movement of both columns can be set within an appropriate range, and impact energy can be absorbed appropriately. In addition, even if the total thickness dimension D2 before press-fitting of the spacer varies, the total thickness dimension D2 before press-fitting of the spacer and the ridge are formed so that the relationship of D2>D1> D3 is established and the impact energy can be appropriately absorbed. A height dimension H of 3d is set.
[0010]
By making the height of the protrusion of the spacer in a state where it is press-fitted between both columns smaller than the thickness of the portion where no protrusion is formed, the spacer is made of a synthetic resin material and is made of metal, etc. Even if it is easy to deform, the relative inclination of both columns due to the deformation of the ridge during impact action is reduced, and both columns are axially moved by the portion where the ridge is not formed and difficult to deform. Since it can be guided so as to move relative to each other, both columns can be smoothly moved relative to each other in the axial direction to appropriately absorb impact energy.
[0011]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
1 to 6 includes a cylindrical metal first column 2a and a metal second column 2b that is press-fitted into the first column 2a via a cylindrical spacer 3. Prepare. The first column 2 a supports a cylindrical first handle shaft 5 via a bearing 4. A steering wheel (not shown) is connected to one end of the first handle shaft 5, and one end of the second handle shaft 7 is inserted to the other end, and the second handle shaft 7 is supported by the second column 2 b via a bearing 6. Is done. The bearing 4 is axially relative to the first column 2 a and the first handle shaft 5 by a step formed on the inner periphery of the first column 2 a and a retaining ring 12 attached to the outer periphery of the first handle shaft 5. Movement is restricted.
[0013]
As shown in FIG. 2, a pair of circumferential grooves 8 are formed on the outer periphery of the second handle shaft 7, and a through hole 9 communicating with the circumferential groove 8 is formed in the first handle shaft 5. Resin 60 is filled in circumferential groove 8. When the impact is applied, the resin 60 is broken, and the first handle shaft 5 and the second handle shaft 7 move relative to each other in the axial direction. Since the inner peripheral shape of the first handle shaft 5 and the outer peripheral shape of the second handle shaft 7 are non-circular, the first handle shaft 5 and the second handle shaft 7 are coupled so as to be able to transmit rotation.
[0014]
The upper bracket 11 is welded to the first column 2a. The upper bracket 11 includes a pair of support portions 11a extending outward in the radial direction of the first column 2a, as shown in FIGS. 3, 4, and 5A. Each of the support portions 11a has a side wall portion 11d that extends perpendicularly to the axial direction of the first column 2a, and a protruding portion 11e that extends from one end of each side wall portion 11d in parallel to the axial direction of the first column 2a. Each support portion 11a is formed with a notch 11b that opens on the steering wheel side. A connecting member 20 is inserted into each notch 11b. As shown in (2) of FIG. 5, each connecting member 20 has an upper portion 20a that enters the inner surface of each notch 11b, and a lower portion 20b that extends along the lower surface around each notch 11b. A plurality of through holes are formed in a portion along the periphery of the notch 11b of each support portion 11a, and a through hole 20c communicating with each through hole is formed in the lower portion 20b of the connecting member 20, and a synthetic resin pin 61 is formed in each through hole. Is inserted. Each pin 61 is integrated with a holding member 61 'along the upper surface around each notch 11b. A plate 63 made of sheet metal is placed on the upper surface of each connecting member 20 and each holding member 61 ′, and planted on the vehicle body side member 45 in the through holes 63 ′ and 20 ′ formed in the plate 63 and each connecting member 20. The screw shaft 40 to be inserted is inserted. The plate 63, the holding member 61 ', the support portion 11a, and the connecting member 20 are sandwiched between the nut 41 and the vehicle body side member 45 that are screwed together with the screw shaft 40. The plate 63 and the through-holes 63 'and 20' of the connecting member 20 are elongated holes in the column axis direction so as to be able to cope with misalignment between members due to manufacturing errors. When the impact is applied, the pin 61 is broken, and the upper bracket 11 moves relative to the plate 63, the holding member 61 ', and the connecting member 20 together with the first column 2a.
[0015]
Each plate 63 includes an upper part 63a sandwiched between the holding member 61 ′ and the vehicle body side member 45, an intermediate part 63b extending from one end of the upper part 63a at right angles to the axial direction of the first column 2a, and an intermediate part 63b A lower portion 63c extending from one end in parallel to the axial direction of the first column 2a. Each intermediate portion 63b is inserted into an opening 11f formed in each support portion 11a of the upper bracket 11 and extends along each side wall portion 11d, and each lower portion 63c extends along the protruding portion 11e. A ring 64 is fitted to each lower portion 63c and the protruding portion 11e. Thus, when an impact is applied and the upper bracket 11 moves relative to the plate 63, the intermediate portion 63b of the plate 63 is pushed by the inner surface of the opening 11f of the upper bracket 11, and the plate 63 is moved as shown in FIG. Plastic deformation.
[0016]
As shown in FIG. 1, the lower bracket 10 is welded to the second column 2 b, and the second column 2 b is attached to the vehicle body via the lower bracket 10.
[0017]
As shown in FIGS. 7 and 8 (1) and 8 (2), the spacer 3 is formed into a cylindrical shape by a synthetic resin material such as nylon, for example, and has a dividing groove 3 a along the axial direction. And has a flange 3b protruding inward at one end. The flange 3b contacts the end surface of the second column 2b. The spacer 3 has a plurality of protrusions 3d formed along the axial direction in a plurality of regions spaced in the circumferential direction of the outer periphery. The outer peripheral region 3e where the protrusion 3d is not formed is a flat cylindrical surface. Thereby, the inner peripheral surface of the first column 2a is in contact with the spacer 3 via each protrusion 3d. As shown in FIG. 8 (3), the height dimension h of the protrusion 3d of the spacer 3 in a state where it is press-fitted between both columns 2a and 2b is the thickness dimension of the portion 3f where the protrusion 3d is not formed. It is made smaller than D3.
[0018]
As shown in FIG. 12, the total thickness D2 both columns 2a before press-fitting of the spacer 3, greater than the gap dimension D1 between 2b, the ridge from the total thickness D 2 of the previous press-fitting of the spacer 3 The dimension D3 obtained by subtracting the height dimension H is made smaller than the gap dimension D1 between the columns 2a and 2b. The spacer 3 before press-fitting is fitted to the outer periphery of the second column 2b, and the flange 3b at one end thereof is in contact with the end surface of the second column 2b. The first column 2a is press-fitted into the outer periphery of the spacer 3, and each protrusion 3d is compressed and deformed during the press-fitting. In addition, even if the total thickness dimension D2 before the press-fitting of the spacer 3 varies, the total thickness dimension D2 before the press-fit of the spacer 3 and the relationship of D2>D1> D3 are established and the impact energy can be appropriately absorbed. The height dimension H of the protrusion 3d is set.
[0019]
In the above configuration, when an impact force is applied due to a vehicle collision, the resins 60 and 61 are sheared and the impact energy is absorbed, and the plates 63 are plastically deformed by the relative movement of both the columns 2a and 2b. The energy is absorbed, and the impact energy corresponding to the load required to move both the columns 2a and 2b in the axial direction is absorbed.
[0020]
According to the above embodiment, the total thickness dimension D2 of the spacer 3 before press-fitting is larger than the gap dimension D1 between the columns 2a and 2b, and the height of the protrusion 3d is higher than the total thickness dimension D2 of the spacer 3 before press-fitting. Since the dimension D3 obtained by subtracting the dimension H is smaller than the gap dimension D1 between the columns 2a and 2b, the amount of compressive deformation at the time of press-fitting the spacer 3 is a cylindrical surface where the inner and outer circumferences of the spacer are flat as in the prior art. Smaller than some cases. As a result, even if the gap dimension D1 between both the columns 2a and 2b and the total thickness dimension D2 before press-fitting of the spacer 3 vary depending on the processing tolerance, the variation in the amount of compressive deformation at the time of press-fitting of the spacer 3 due to the variation is The variation in the load required for the relative movement in the axial direction of both the columns 2a and 2b corresponding to the press-fit load can be reduced as compared with the conventional case. The two-dot chain line in FIG. 13 indicates the variation from the set value of the gap dimension D1 between the columns 2a and 2b and the axial direction when the total thickness D2 before press-fitting of the spacer 3 of the above embodiment is constant. The relationship with the load required for relative movement is shown, and it can be confirmed that the variation in the load with respect to the variation in the gap dimension D1 is smaller than the variation in the load of the conventional spacer indicated by the solid line. Thereby, the load required for the axial relative movement of both the columns 2a and 2b can be set within an appropriate range, and impact energy can be absorbed appropriately.
[0021]
Further, by making the height dimension h of the protrusion 3d of the spacer 3 in a state where it is press-fitted between both the columns 2a and 2b, smaller than the thickness dimension D3 of the portion 3f where the protrusion 3d is not formed, Even if the spacer 3 is made of a synthetic resin material and is more easily deformed than metal or the like, the relative inclination of both the columns 2a and 2b due to the deformation of the protrusion 3d at the time of impact is reduced, and the protrusion Since both columns 2a and 2b can be guided so as to move relative to each other in the axial direction by the portion 3f which is not formed with the stripe 3d, the two columns 2a and 2b are smoothly moved relative to each other in the axial direction to appropriately absorb the impact energy. it can.
[0022]
In addition, this invention is not limited to the said Example. For example, in the above embodiment, the spacer 3 has a cylindrical shape. However, as shown in FIG. 9, the spacer 3 has a shape having a plurality of notches 3g opened at one end of the cylindrical shape, and the protrusion 3d is provided on the entire outer periphery excluding the notches 3g. It may be provided. In the above embodiment, the protrusions 3d are formed in a plurality of regions spaced in the circumferential direction of the outer periphery of the cylindrical spacer 3. However, as shown in FIG. 10, the protrusions 3d are formed in the entire outer region. May be. In this case, the amount of compressive deformation at the time of press-fitting of the spacer 3 is smaller than that in the prior art, but is larger than that in the above embodiment. Therefore, as shown by the broken line in FIG. The variation in the load required for the relative movement in the axial direction of both the columns 2a and 2b with respect to the variation from the value is smaller than that of the conventional spacer shown by the solid line, but is larger than that in the above embodiment. In the above embodiment, the flange 3b projecting inward from one end of the spacer 3 is brought into contact with the end surface of the second column 2b. However, as shown in FIG. 11, the flange projecting outward from one end of the spacer 3 is used. 3h may be brought into contact with the end surface of the first column 2a. In this case, the protrusion is provided on the inner periphery of the spacer 3. Further, protrusions may be provided on both the inner periphery and the outer periphery of the spacer 3. Moreover, in the said Example, although the protrusion 3d was provided along the axial direction of the spacer 3, you may provide a protrusion along the circumferential direction of a spacer. Moreover, although the said Example demonstrated that the cross-sectional shape of the protrusion 3d of the spacer 3 was a substantially triangular shape, it is good also considering the cross-sectional shape as a substantially trapezoid.
[Brief description of the drawings]
FIG. 1 is a sectional view of a steering column according to an embodiment of the present invention. FIG. 2 is a partial sectional view of the steering column. FIG. 3 is a partial side view of the steering column. 5 is a partial sectional view of the steering column, and FIG. 6 is a perspective view of the connecting member and the holding member. FIG. 6 is a side view of the steering column after the impact action. FIG. 8 is a longitudinal sectional view of the spacer, (2) is a transverse sectional view, and (3) is a partial sectional view in a state of being press-fitted between both columns. FIG. 9 is a modification of the present invention. FIG. 10 is a perspective view of a spacer according to a modification of the present invention. FIG. 11 is a partial sectional view of a steering column according to a modification of the present invention. 13] Both columns Figure 14 is a view illustrating the operation of a conventional steering column showing the relationship between the load required the gap variation and both columns to move axially relative to EXPLANATION OF REFERENCE NUMERALS
2a First column 2b Second column 3 Spacer 3d Projection

Claims

In the shock absorption type steering column in which the cylindrical second column is press-fitted into the cylindrical first column via the cylindrical spacer,
The spacer is formed of a synthetic resin material and has a plurality of protrusions formed on at least one of the outer periphery and the inner periphery,
At least one of the inner periphery of the first column and the outer periphery of the second column is in contact with the spacer via the protrusions,
Except for the protrusions, the outer periphery of the spacer is along the inner periphery of the first column and the inner periphery of the spacer is along the outer periphery of the second column.
The height of the protrusion of the spacer press-fitted between both columns is made smaller than the thickness of the portion excluding the protrusion ,
The total thickness dimension, which is the sum of the thickness dimension of the portion excluding the protrusions before press-fitting of the spacer and the height dimension of the protrusions, is made larger than the gap dimension between both columns,
The dimension obtained by subtracting the height dimension of the ridge from the total thickness dimension before press-fitting the spacer is made smaller than the gap dimension between both columns,
An impact-absorbing steering column, wherein the protrusions are compressed and deformed by the inner periphery of the first column and the outer periphery of the second column in a press-fitted state through the spacers of both columns .

In manufacturing the shock absorbing type steering column according to claim 1, the total thickness dimension, which is the sum of the thickness dimension of the portion excluding the protrusion and the height of the protrusion before the spacer is press-fitted, is set between the two columns. The dimension obtained by subtracting the height dimension of the ridge from the total thickness dimension before press-fitting of the spacer is made smaller than the gap dimension between both columns, and each ridge is compressed and deformed. A method for manufacturing an impact-absorbing steering column, wherein a second column is press-fitted into one column via a spacer.