JP2004231127A

JP2004231127A - Steering device

Info

Publication number: JP2004231127A
Application number: JP2003024844A
Authority: JP
Inventors: Michiaki Yamaoka; 道明山岡; Takeshi Matsuda; 剛松田
Original assignee: Koyo Seiko Co Ltd
Current assignee: Koyo Seiko Co Ltd
Priority date: 2003-01-31
Filing date: 2003-01-31
Publication date: 2004-08-19
Anticipated expiration: 2023-01-31
Also published as: JP4085829B2

Abstract

<P>PROBLEM TO BE SOLVED: To easily correct unevenness of the sliding resistance between an inside cylinder and an outside cylinder forming a column housing, and to accurately realize desirable impact absorbing performance. <P>SOLUTION: The column housing 2 is provided with the inside cylinder 22 and the outside cylinder 23 engaged with each other over an appropriate length, and absorbs an impact of a secondary collision with the sliding resistance when both the cylinders slide in the axial direction. The inside cylinder 22 to be brought in pressure-contact with four resistant projections 24 and 24 projected from the inner peripheral surface of the outside cylinder 23, is formed to have an octagonal cross section provided with a set of four sides 25 and 25 corresponding to the number of parallel arrangement of the resistant projections 24 and 24 and a set of a plurality of sides 26 and 26, and formed to select an assembling that the sides 25 and 25 are brought into pressure-contact with the resistant projections 24 and 24, and an assembling that the sides 26 and 26 are brought into pressure-contact with the resistant projections 24 and 24, while forming a diameter D<SB>1</SB>of a circle inscribed with one sides 25 and 25 and a diameter D<SB>2</SB>of a circle inscribed with the other sides 26 and 26 different from each other. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、車両の衝突時にコラム軸に加えられる二次衝突の衝撃エネルギを、該コラム軸を支持する筒形のコラムハウジングが軸長方向に短縮することにより吸収する構成としてあるステアリング装置に関する。
【０００２】
【従来の技術】
車両の操舵は、車室の内部に配されたステアリングホイールに加えられる操舵トルクを、操舵用の車輪（一般的には前輪）の舵取りのために車室の外部に配された舵取機構に伝えて行われる。このような操舵を行わせるためのステアリング装置は、車室の内部に軸回りでの回転自在に支持されたコラム軸の上端部に、運転者に対面するようにステアリングホイールを取付け、また前記コラム軸の下端部を舵取機構に連結して構成されている。
【０００３】
このようなステアリング装置においては、近年、車両の前面衝突に伴って前方への慣性の作用によりステアリングホイールに衝突（二次衝突）する運転者に加わるダメージを軽減すべく、前記二次衝突の衝撃エネルギを吸収する衝撃吸収式のステアリング装置として構成されたものが実用化されている。
【０００４】
前記衝撃エネルギの吸収は、一般的に、前記コラム軸を回転自在に支持するコラムハウジングを利用して実現されており、適長に亘って内外に嵌め合わされ、二次衝突時の衝撃の作用によりテレスコピックに短縮する内筒及び外筒を備えて前記コラムハウジングを構成し、前記衝撃のエネルギを、前記内筒及び外筒の短縮時に両者の嵌合部に加わる摺動抵抗により吸収せしめるようになしてある（例えば、特許文献１参照）。
【０００５】
【特許文献１】
特開２００２−２９３２４９号公報
【０００６】
【発明が解決しようとする課題】
さて、以上の如く構成された衝撃吸収式のステアリング装置においては、ステアリングホイールに衝突する運転者に、内筒及び外筒間の摺動抵抗の反力が加わることから、前記運転者のダメージを軽減するという初期の目的を達成するために、前記摺動抵抗の値を予め設定された全長に亘って略一定の摺動抵抗下にて相対摺動せしめることが重要である。
【０００７】
前記特許文献１に記載されたステアリング装置は、外筒の周壁を軸長方向に適長離れた２位置にてかしめ、夫々の位置の内周面に内向きに突出する抵抗突起を各複数（４つ）並設し、これらの抵抗突起を内側に対向する円筒形の内筒の外周面に圧接させて、この圧接部において衝撃吸収のための摺動抵抗を付与するという簡易な構成の衝撃吸収構造を備えており、製品コストの低減を図っている。
【０００８】
しかしながらこの構成においては、内筒と外筒との間の摺動抵抗が、外筒のかしめにより形成される抵抗突起と円筒形をなす内筒の外周面との圧接強さに依存するが、この圧接強さには、抵抗突起の突出量、内筒の外径等、各部の寸法誤差が影響するため、内筒及び外筒の組み付け後に実際に得られる摺動抵抗にばらつきが生じることが避けられず、このばらつきを修正し、所望の衝撃吸収性能を精度良く実現するために、例えば、抵抗突起の手直し、又は内筒及び外筒の組み合わせを変えての組み直しが必要となり、組み付け工数の増大を招来し、構成の簡素化による満足すべきコストの低減効果が得られないという問題があった。
【０００９】
本発明は斯かる事情に鑑みてなされたものであり、コラムハウジングを構成する内筒と外筒との間に各部の寸法誤差の影響により発生する摺動抵抗のばらつきを簡易に修正可能とし、内筒と外筒との間に二次衝突時の衝撃吸収のために発生する摺動により、所望の衝撃吸収性能を高精度に実現し得るステアリング装置を提供することを目的とする。
【００１０】
【課題を解決するための手段】
本発明に係るステアリング装置は、ステアリングホイールの操舵トルクを舵取機構に伝達するコラム軸を、適長に亘って内外に嵌合された内筒及び外筒を備えるコラムハウジングの内部に支持し、前記外筒の内周面に周方向に略等配をなして配設された複数の抵抗突起を前記内筒の外周面に圧接させて、車両の衝突時に前記ステアリングホイールを介して前記コラム軸に加わる二次衝突の衝撃エネルギを、前記抵抗突起による付与抵抗下にて生じる前記内筒及び外筒の軸長方向の相対摺動により吸収するステアリング装置において、前記内筒は、前記複数の抵抗突起に同時に圧接可能な辺の組を複数組備える多角形断面を有しており、各組の辺の内接円の直径が相互に異ならせてあることを特徴とする。
【００１１】
本発明においては、外筒に嵌合される内筒を、外筒内周の抵抗突起の並設数の複数倍の辺を備える多角形断面を有する筒体とし、抵抗突起に同時に圧接可能な複数の辺の組に内接する円の直径を異ならせておき、外筒への組み付けに際し、この外筒に設けられた抵抗突起の実寸に対応する直径を有する辺の組を選定し、これらの辺の組を抵抗突起の突設位置に整合させ、抵抗突起との間に適正な圧接強さが得られるように組み付けを実施し、所望の衝撃吸収性能が得られるようにする。
【００１２】
【発明の実施の形態】
以下本発明をその実施の形態を示す図面に基づいて詳述する。図１は、本発明に係るステアリング装置の全体構成を示す模式図である。
【００１３】
図中１は、コラム軸であり、該コラム軸１は、円筒形をなすコラムハウジング２の内部に同軸的に支承され、該コラムハウジング２の中途部に固設されたアッパブラケット３とコラムハウジング２の一端部に固設されたロアブラケット４とにより、ロアブラケット４の側を前下方（図における左下方）に向けた傾斜姿勢にて車室の内部に支持されている。
【００１４】
コラムハウジング２の上部に突出するコラム軸１の上端部には、車室内部の運転者に対面するようにステアリングホイール１０が嵌着固定され、同じく下部に突出するコラム軸１の下端部は、両端にユニバーサルジョイント５０，５０を備える中間軸５を介して舵取機構６の入力軸６０に連結されている。以上の構成により、運転者により操舵のためにステアリングホイール１０に加えられる操舵トルクは、コラム軸１及び中間軸５を介して舵取機構６の入力軸６０に伝達され、該舵取機構６の動作により操舵が実行される。
【００１５】
なお図１に示すステアリング装置は、コラムハウジング２の下端部近傍に取付けられた操舵補助用のモータ２０を備え、また該モータ２０よりも上位置のコラムハウジング２の内部にトルクセンサ２１を備え、該トルクセンサ２１により、ステアリングホイール１０に加えられる操舵トルクを検出し、この検出トルクに基づいて駆動されるモータ２０の回転力をコラムハウジング２内部のコラム軸１に伝えて、前述の如く行われる操舵を補助する電動パワーステアリング装置として構成されているが、本発明に係るステアリング装置は、運転者によりステアリングホイール１０に加えられる操舵トルクのみによって操舵を行わせるマニュアル式のステアリング装置であってもよく、また舵取機構６に付設された油圧シリンダの発生力により操舵を補助する油圧パワーステアリング装置であってもよい。
【００１６】
本発明に係るステアリング装置において、トルクセンサ２１の内蔵部分の上位置に連続するコラムハウジング２の上半部は、適長に亘って内外に嵌合され、軸長方向への相対移動可能に組み合わされた内筒２２及び外筒２３を備えている。コラムハウジング２の上部を車体に支持するアッパブラケット３は、外筒２３の中途部に固設されており、コラムハウジング２に下向きに加わる所定限度を超える力の作用により、車体側の固定部にカプセル３０を残して下方に離脱する公知のブレークアウエイブラケットとして構成されている。
【００１７】
図２は、内筒２２及び外筒２３の嵌合部の一部破断側面図である。上側に位置する外筒２３は、薄肉の円筒体であり、この外筒２３の内周面には、内筒２２の嵌め込み口が開口する下端部近傍と、下端部から上方に適長離れた位置とに、周方向に等配をなして各複数の抵抗突起２４，２４…が突設され、内側に嵌合された内筒２２の外周面に圧接されている。
【００１８】
図３は、内筒２２及び外筒２３の嵌合部近傍の分解斜視図である。本図に示す如く外筒２３の下端近傍の抵抗突起２４，２４…は、外筒２３の周壁を外側からかしめ、内周面に所定の突出量を有して形成されている。これらの抵抗突起２４，２４…は、周方向に４つ並設されているが、これらの並設数は、３つであってもよく、５つ以上であってもよい。また外筒２３の下端近傍から離れた位置の抵抗突起２４，２４…も、同様の形成態様にて、同数並設されている。
【００１９】
本発明に係るステアリング装置の特徴は、以上の如き抵抗突起２４，２４…を備える外筒２３に内嵌される内筒２２の構成にあり、該内筒２２は、図３に示す如く、抵抗突起２４，２４…の並設数の２倍、即ち、８つの辺を有する８角形断面の筒体としてある。
【００２０】
図４は、図２のＩＶ−ＩＶ線による内筒２２及び外筒２３の嵌合部の横断面図であり、前述の如く８角形断面を有する内筒２２は、周方向に１つ置きに位置する４つの辺の組を２組（辺２５，２５…及び辺２６，２６…）備えており、いずれか一方の組を外筒２３の内周面に突設された抵抗突起２４，２４…の周方向位置に整合させ、この状態で外筒２３に圧入せしめることにより、図４（ａ）に示す如く、辺２５，２５…の夫々に抵抗突起２４，２４…を圧接させた組み付けと、図４（ｂ）に示す如く、辺２６，２６…の夫々に抵抗突起２４，２４…を圧接させた組み付けとが可能である。
【００２１】
ここで、一方の組の辺２５，２５…は、これらに内接する円の直径がＤ_１となるように、他方の組の辺２６，２６…は、同様に内接する円の直径がＤ_２となるように形成されており、これらの直径Ｄ_１，Ｄ_２を相互に異ならせ、例えば、Ｄ_１＞Ｄ_２となるように設定してある。従って、図４（ａ），（ｂ）に夫々示す組み付けを同一の外筒２３に対して実施した場合、内筒２２の外周面に対する抵抗突起２４，２４…の圧接強さは、図４（ａ）に示す組み付け状態において大きく、図４（ｂ）に示す組み付け状態において小さくなる。
【００２２】
このように内筒２２は、外筒２３の４つの抵抗突起２４，２４…と同時に当接可能な２組の辺２５，２５…及び辺２６，２６…を備え、各組の内接円の直径Ｄ_１，Ｄ_２を相互に異ならせてある８角形断面を有することから、係合突起２４，２４…の圧接強さを２通りに変えた組み付けが可能となり、いずれの組み付けを行うかを、例えば、組み付け対象となる外筒２３に設けられた係合突起２４，２４…の実寸に応じて選定すれば、適正な圧接強さでの組み付けを簡易に実現することができる。
【００２３】
ここで内筒２２は、外筒２３に設けられる抵抗突起２４，２４…の数の整数倍の辺を有する多角形断面とすればよく、前述の如く、外筒２３が４つの抵抗突起２４，２４を備える場合、８角形断面の外に、１２角形断面、１６角形断面等、４の複数倍の辺を有する多角形断面とすることができる。
【００２４】
なお、１２角形断面を採用した場合、係合突起２４，２４…の圧接強さを３通りに変えた組み付けが、１６角形断面を採用した場合、同じく４通りに変えた組み付けが可能となり、組み付けの自由度が増すが、辺の数を多くした場合、各辺の長さが短くなり、抵抗突起２４，２４…との間に十分な圧接幅を確保することが難しくなるため、過度に多くの辺を有する多角形断面の採用は好ましくない。
【００２５】
また、外筒２３が３つの抵抗突起２４，２４…を備える場合、６角形断面、９角形断面、１２角形断面等、３の整数倍の辺を有する多角形断面を有する内筒２２を用いればよく、外筒２３が５つの抵抗突起２４，２４…を備える場合、５角形断面、１０角形断面等、５の整数倍の辺を有する多角形断面を有する内筒２２を用いればよいことは言うまでもない。
【００２６】
以上の如き内筒２２及び外筒２３を備えるコラムハウジング２には、車両の前面衝突時に、前方への慣性の作用によりステアリングホイール１０に運転者が衝突（二次衝突）したとき、図１中に白抜矢符にて示す如く、軸長方向の下向きに衝撃力が加わる。
【００２７】
このとき、前述の如くブレークアウエイブラケットとして構成されたアッパブラケット３が車体から離脱し、該アッパブラケット３による拘束が解かれた外筒２３は、前記押圧力の作用により内筒２２に対して摺動しつつ、図１中にＳとして示す摺動ストローク間にて下方に相対移動し、この相対移動によるコラムハウジング２の短縮により二次衝突に伴う衝撃のエネルギが吸収される。
【００２８】
このようになされる衝撃吸収動作において、ステアリングホイール１０に衝突した運転者には、内筒２２と外筒２３との間の摺動抵抗、より詳しくは、外筒２３に設けられた抵抗突起２４，２４…と内筒２２の外周面との圧接部における摺動抵抗が反力として加わる。ここで本発明に係るステアリング装置においては、前述した多角形断面を有する内筒２２の採用により、抵抗突起２４，２４…の圧接強さが適正に保たれた組み付けがなされているため、前記摺動抵抗を高精度に設定することができ、摺動ストロークＳ間の摺動により所望の衝撃吸収性能を確実に実現することが可能となり、この間運転者は、大なるダメージを受けることなく保護される。
【００２９】
なお、図４においては、説明の都合上、内筒２２の一方の組の辺２５，２５…の内接円の直径Ｄ_１と、他方の組の辺２６，２６…の内接円の直径Ｄ_２との差を大きくしてあるが、これらの差の実際値は、外筒２３の内径、抵抗突起２４，２４…の突出量等、関連する各部における寸法公差の範囲内において設定される微小な値である。
【００３０】
【発明の効果】
以上詳述した如く本発明に係るステアリング装置においては、外筒の内周面に突設された抵抗突起に、多角形断面を有する内筒の複数組の辺のいずれかを選択的に圧接させて組み付けを行うことにより、二次衝突時の衝撃吸収のために内筒と外筒とが軸長方向に摺動する際の摺動抵抗の適正化を簡易に実施でき、所望の衝撃吸収性能を高精度に実現することが可能となる等、本発明は優れた効果を奏する。
【図面の簡単な説明】
【図１】本発明に係るステアリング装置の全体構成を示す模式図である。
【図２】内筒及び外筒の嵌合部の一部破断側面図である。
【図３】内筒及び外筒の嵌合部近傍の分解斜視図である。
【図４】図２のＩＶ−ＩＶ線による内筒及び外筒の嵌合部の横断面図である。
【符号の説明】
１コラム軸
２コラムハウジング
６舵取機構
１０ステアリングホイール
２２内筒
２３外筒
２４抵抗突起
２５辺
２６辺[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steering device configured to absorb the impact energy of a secondary collision applied to a column shaft at the time of a vehicle collision by shortening in a shaft length direction a cylindrical column housing supporting the column shaft.
[0002]
[Prior art]
The steering of the vehicle is performed by applying a steering torque applied to a steering wheel disposed inside the vehicle compartment to a steering mechanism disposed outside the vehicle compartment for steering a steering wheel (generally, a front wheel). It is done by telling. A steering device for performing such steering is provided with a steering wheel attached to an upper end portion of a column shaft rotatably supported around an axis in a vehicle interior so as to face a driver. The lower end of the shaft is connected to a steering mechanism.
[0003]
In recent years, such a steering apparatus has been designed to reduce the impact of the secondary collision on the driver who collides with the steering wheel (secondary collision) due to the action of inertia in front due to the frontal collision of the vehicle. 2. Description of the Related Art A device configured as a shock absorbing steering device that absorbs energy has been put to practical use.
[0004]
Generally, the absorption of the impact energy is realized by using a column housing that rotatably supports the column shaft, is fitted inside and outside over an appropriate length, and is acted upon by an impact at the time of a secondary collision. The column housing is provided with an inner cylinder and an outer cylinder that are shortened to telescopic, and the energy of the impact is absorbed by sliding resistance applied to a fitting portion between the inner cylinder and the outer cylinder when the inner cylinder and the outer cylinder are shortened. (For example, see Patent Document 1).
[0005]
[Patent Document 1]
JP 2002-293249 A
[Problems to be solved by the invention]
By the way, in the shock absorbing type steering device configured as described above, the reaction force of the sliding resistance between the inner cylinder and the outer cylinder is applied to the driver colliding with the steering wheel. In order to achieve the initial purpose of reducing the sliding resistance, it is important that the sliding resistance is relatively slid under a substantially constant sliding resistance over a preset length.
[0007]
In the steering device described in Patent Document 1, the peripheral wall of the outer cylinder is swaged at two positions that are appropriately spaced apart in the axial direction, and a plurality of inwardly projecting resistance protrusions are formed on the inner peripheral surface at each position ( 4) An impact having a simple configuration in which the resistance protrusions are arranged side by side and pressed against the outer peripheral surface of a cylindrical inner cylinder opposed to the inside to provide sliding resistance for absorbing the shock at the pressure contact portion. Equipped with an absorption structure to reduce product costs.
[0008]
However, in this configuration, the sliding resistance between the inner cylinder and the outer cylinder depends on the pressure contact strength between the resistance protrusion formed by caulking the outer cylinder and the outer peripheral surface of the cylindrical inner cylinder, Since the dimensional error of each part such as the amount of protrusion of the resistance protrusion and the outer diameter of the inner cylinder influences the pressure contact strength, the sliding resistance actually obtained after assembling the inner cylinder and the outer cylinder may vary. Inevitably, in order to correct this variation and accurately realize the desired shock absorption performance, for example, it is necessary to reconfigure the resistance protrusions or reassemble by changing the combination of the inner cylinder and the outer cylinder, and the number of assembly steps is reduced. However, there is a problem that a satisfactory cost reduction effect cannot be obtained by simplification of the configuration.
[0009]
The present invention has been made in view of such circumstances, and enables to easily correct a variation in sliding resistance generated due to an influence of a dimensional error of each part between an inner cylinder and an outer cylinder constituting a column housing, It is an object of the present invention to provide a steering device capable of realizing a desired shock absorbing performance with high precision by sliding generated between an inner cylinder and an outer cylinder for absorbing a shock in a secondary collision.
[0010]
[Means for Solving the Problems]
The steering device according to the present invention supports a column shaft that transmits a steering torque of a steering wheel to a steering mechanism inside a column housing including an inner cylinder and an outer cylinder fitted in and out over an appropriate length, A plurality of resistance protrusions arranged substantially equidistantly in the circumferential direction on the inner peripheral surface of the outer cylinder are pressed against the outer peripheral surface of the inner cylinder, and the column shaft is provided via the steering wheel during a vehicle collision. In the steering device, the impact energy of the secondary collision applied to the inner cylinder is absorbed by the relative sliding of the inner cylinder and the outer cylinder in the axial direction generated under the applied resistance by the resistance projection, the inner cylinder includes the plurality of resistances. It has a polygonal cross-section having a plurality of sets of sides that can be pressed against the projection at the same time, and the diameters of the inscribed circles of the sides of each set are different from each other.
[0011]
In the present invention, the inner cylinder fitted to the outer cylinder is a cylindrical body having a polygonal cross section having a side multiple times the number of juxtaposed resistance projections on the inner periphery of the outer cylinder, and can be pressed against the resistance projections simultaneously. The diameter of the circle inscribed in the plurality of sets of sides is made different, and when assembling to the outer cylinder, a set of sides having a diameter corresponding to the actual size of the resistance protrusion provided on the outer cylinder is selected, and these are set. The set of sides is aligned with the protruding position of the resistance protrusion, and the assembly is performed so as to obtain an appropriate pressure contact strength with the resistance protrusion, so that a desired shock absorbing performance is obtained.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments. FIG. 1 is a schematic diagram showing an entire configuration of a steering device according to the present invention.
[0013]
In the figure, reference numeral 1 denotes a column shaft. The column shaft 1 is coaxially supported inside a column housing 2 having a cylindrical shape, and an upper bracket 3 and a column housing fixed to an intermediate portion of the column housing 2. The lower bracket 4 is fixed to one end of the second bracket 2 and is supported in the interior of the vehicle cabin with the lower bracket 4 side inclined downward and forward (to the lower left in the drawing).
[0014]
A steering wheel 10 is fitted and fixed to an upper end of the column shaft 1 protruding above the column housing 2 so as to face a driver in the vehicle interior. It is connected to an input shaft 60 of the steering mechanism 6 via an intermediate shaft 5 having universal joints 50 at both ends. With the above configuration, the steering torque applied to the steering wheel 10 by the driver for steering is transmitted to the input shaft 60 of the steering mechanism 6 via the column shaft 1 and the intermediate shaft 5, and Steering is performed by the operation.
[0015]
The steering device shown in FIG. 1 includes a steering assist motor 20 mounted near the lower end of the column housing 2 and a torque sensor 21 inside the column housing 2 located above the motor 20. The torque sensor 21 detects the steering torque applied to the steering wheel 10 and transmits the torque of the motor 20 driven based on the detected torque to the column shaft 1 inside the column housing 2 to perform the operation as described above. Although configured as an electric power steering device that assists steering, the steering device according to the present invention may be a manual steering device that performs steering only with the steering torque applied to the steering wheel 10 by the driver. Also, the steering is performed by the force generated by a hydraulic cylinder attached to the steering mechanism 6. The may be a hydraulic power steering device for assisting.
[0016]
In the steering device according to the present invention, the upper half of the column housing 2 that is continuous with the upper part of the built-in portion of the torque sensor 21 is fitted inside and outside over an appropriate length, and is combined so as to be relatively movable in the axial direction. The inner cylinder 22 and the outer cylinder 23 are provided. The upper bracket 3 for supporting the upper part of the column housing 2 on the vehicle body is fixedly provided in the middle part of the outer cylinder 23, and the upper bracket 3 is fixed to the vehicle body side fixed portion by the action of a force applied to the column housing 2 downward beyond a predetermined limit. It is configured as a known breakaway bracket that detaches downward while leaving the capsule 30.
[0017]
FIG. 2 is a partially broken side view of a fitting portion between the inner cylinder 22 and the outer cylinder 23. The outer cylinder 23 located on the upper side is a thin cylindrical body, and the inner peripheral surface of the outer cylinder 23 is near the lower end where the fitting opening of the inner cylinder 22 opens, and is separated from the lower end by an appropriate length upward. A plurality of resistance protrusions 24 are provided at equal positions in the circumferential direction so as to protrude, and are pressed against the outer peripheral surface of the inner cylinder 22 fitted inside.
[0018]
FIG. 3 is an exploded perspective view in the vicinity of a fitting portion between the inner cylinder 22 and the outer cylinder 23. As shown in the figure, the resistance projections 24, 24,... Near the lower end of the outer cylinder 23 are formed so as to crimp the peripheral wall of the outer cylinder 23 from the outside and have a predetermined projection amount on the inner peripheral surface. .. Are arranged side by side in the circumferential direction, but the number of these arranged may be three or may be five or more. The resistance protrusions 24, 24,... At positions away from the vicinity of the lower end of the outer cylinder 23 are arranged in the same number and in the same manner.
[0019]
The feature of the steering device according to the present invention lies in the structure of the inner cylinder 22 fitted inside the outer cylinder 23 having the above-described resistance protrusions 24, 24,..., As shown in FIG. The number of the projections 24 is twice the number of juxtapositions, that is, a cylinder having an octagonal cross section having eight sides.
[0020]
FIG. 4 is a cross-sectional view of the fitting portion of the inner cylinder 22 and the outer cylinder 23 taken along the line IV-IV in FIG. 2. As described above, the inner cylinders 22 having an octagonal cross section are alternately arranged in the circumferential direction. Two sets of four sides are located (sides 25, 25 ... and sides 26, 26 ...), and one of the sets is provided with resistance projections 24, 24 protruding from the inner peripheral surface of the outer cylinder 23. Are fitted to the outer cylinder 23 in this state, and as shown in FIG. 4 (a), the resistance protrusions 24, 24 are pressed against the sides 25, 25, respectively. As shown in FIG. 4 (b), assembly is possible in which the resistance protrusions 24, 24,.
[0021]
Here, the edges 25, 25 are one set, as the diameter of a circle inscribed in these is D _1, the set of edges 26, 26 on the other hand, the circle inscribed in the same manner diameter D ₂ The diameters D ₁ and D ₂ are different from each other, and are set so that, for example, D ₁ > D ₂ . 4 (a) and 4 (b) are applied to the same outer cylinder 23, the pressing strength of the resistance projections 24, 24... Against the outer peripheral surface of the inner cylinder 22 is as shown in FIG. It is large in the assembled state shown in FIG. 4A and small in the assembled state shown in FIG.
[0022]
As described above, the inner cylinder 22 includes the two sets of sides 25, 25, and the sides 26, 26, which can be simultaneously contacted with the four resistance protrusions 24, 24, of the outer cylinder 23. Since it has an octagonal cross section in which the diameters D ₁ and D ₂ are different from each other, it is possible to assemble the engagement projections 24 with different press-contact strengths of the engagement projections 24, 24. For example, if it is selected according to the actual size of the engagement protrusions 24 provided on the outer cylinder 23 to be assembled, it is possible to easily realize the assembly with an appropriate press-contact strength.
[0023]
Here, the inner cylinder 22 may have a polygonal cross section having sides that are an integral multiple of the number of the resistance projections 24 provided on the outer cylinder 23. As described above, the outer cylinder 23 includes the four resistance projections 24, 24,. When 24 is provided, in addition to the octagonal cross-section, a polygonal cross-section having a multiple of four sides, such as a dodecagonal cross-section or a hexagonal cross-section, can be provided.
[0024]
When a dodecagonal cross section is adopted, assembling in which the pressure contact strength of the engagement protrusions 24, 24... Is changed in three ways is possible. In a case where a hexagonal cross section is adopted, assembling in four different ways becomes possible. However, when the number of sides is increased, the length of each side becomes short, and it becomes difficult to secure a sufficient pressure contact width between the resistance protrusions 24, 24. It is not preferable to use a polygonal cross section having the side of.
[0025]
When the outer cylinder 23 has three resistance projections 24, 24,..., The inner cylinder 22 having a polygonal cross section having an integral multiple of 3, such as a hexagonal cross section, a non-decagonal cross section, or a dodecagon cross section, is used. Of course, when the outer cylinder 23 has five resistance projections 24, 24,..., It is needless to say that the inner cylinder 22 having a polygonal cross section having an integer multiple of 5, such as a pentagonal cross section or a 10-sided cross section, may be used. No.
[0026]
When the driver collides with the steering wheel 10 (secondary collision) due to the inertia in the front at the time of a frontal collision of the vehicle, the column housing 2 including the inner cylinder 22 and the outer cylinder 23 as described above is shown in FIG. As shown by a white arrow, an impact force is applied downward in the axial direction.
[0027]
At this time, the upper bracket 3 configured as a breakaway bracket as described above separates from the vehicle body, and the outer cylinder 23 released from the restraint by the upper bracket 3 slides on the inner cylinder 22 by the action of the pressing force. While moving, it relatively moves downward during a sliding stroke shown as S in FIG. 1, and the energy of the impact accompanying the secondary collision is absorbed by the shortening of the column housing 2 due to this relative movement.
[0028]
In the shock absorbing operation performed in this manner, a driver colliding with the steering wheel 10 is provided with a sliding resistance between the inner cylinder 22 and the outer cylinder 23, more specifically, a resistance protrusion 24 provided on the outer cylinder 23. , 24... And the outer peripheral surface of the inner cylinder 22 at the press contact portion as a reaction force. Here, in the steering device according to the present invention, the inner cylinder 22 having the above-described polygonal cross section is used to assemble the resistance projections 24, 24,. The dynamic resistance can be set with high accuracy, and the desired shock absorbing performance can be reliably realized by sliding between the sliding strokes S. During this time, the driver is protected without receiving any serious damage. You.
[0029]
In FIG. 4, for convenience of explanation, the one set of sides 25, 25 the diameter D ₁ of the inscribed circle of the inner cylinder 22, the diameter of the other set of sides 26, 26 inscribed circle of Although is made larger the difference between D _2, the actual values of these differences, the inner diameter of the outer cylinder 23, the resistance protrusions 24, 24 ... protruding amount of the is set within a range of dimensional tolerance in the relevant respective parts This is a minute value.
[0030]
【The invention's effect】
As described in detail above, in the steering device according to the present invention, any one of a plurality of sets of sides of the inner cylinder having a polygonal cross section is selectively pressed against the resistance projection projecting from the inner peripheral surface of the outer cylinder. By assembling it, it is possible to easily optimize the sliding resistance when the inner cylinder and outer cylinder slide in the axial direction to absorb the impact in the event of a secondary collision, and achieve the desired impact absorption performance The present invention has an excellent effect, for example, it is possible to realize the method with high accuracy.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of a steering device according to the present invention.
FIG. 2 is a partially cutaway side view of a fitting portion between an inner cylinder and an outer cylinder.
FIG. 3 is an exploded perspective view of the vicinity of a fitting portion between an inner cylinder and an outer cylinder.
FIG. 4 is a cross-sectional view of a fitting portion of the inner cylinder and the outer cylinder taken along line IV-IV in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Column shaft 2 Column housing 6 Steering mechanism 10 Steering wheel 22 Inner cylinder 23 Outer cylinder 24 Resistance protrusion 25 Side 26 Side

Claims

A column shaft for transmitting the steering torque of the steering wheel to the steering mechanism is supported inside a column housing including an inner cylinder and an outer cylinder fitted in and out over an appropriate length, and provided on an inner peripheral surface of the outer cylinder. A plurality of resistance protrusions arranged substantially equally in the circumferential direction are pressed against the outer peripheral surface of the inner cylinder, and the impact energy of a secondary collision applied to the column shaft via the steering wheel during a vehicle collision In the steering device that absorbs by the relative sliding in the axial direction of the inner cylinder and the outer cylinder generated under the applied resistance by the resistance protrusion,
The inner cylinder has a polygonal cross-section including a plurality of sets of sides that can be pressed against the plurality of resistance protrusions at the same time, and the diameters of inscribed circles of the sides of each set are different from each other. Characteristic steering device.