JP3770031B2

JP3770031B2 - Steering wheel core

Info

Publication number: JP3770031B2
Application number: JP2000026496A
Authority: JP
Inventors: 健二森; 明彦園部; 一三志賀
Original assignee: Toyoda Gosei Co Ltd
Current assignee: Toyoda Gosei Co Ltd
Priority date: 2000-02-03
Filing date: 2000-02-03
Publication date: 2006-04-26
Anticipated expiration: 2020-02-03
Also published as: JP2001213329A

Description

【０００１】
【発明の属する技術分野】
本発明は、ステアリングホイールの芯金に係り、詳しくはリング部芯金の必要な剛性を確保しつつ、その軽量化を図ることができるステアリングホイールの芯金に関するものである。
【０００２】
【従来の技術】
一般に、ステアリングホイールは、所定の剛性を確保するためその内部に芯金を有している。この芯金を図１４により説明する。図１４は芯金を上下逆にした斜視図である。この芯金はリング部芯金１４と、その内側に連結された４本のスポーク部芯金１７〜２０と、各スポーク部芯金１７〜２０を連結する連結芯金２１に一体形成されたボス部２１ａとにより構成されている。
【０００３】
前記リング部芯金１４は所定の剛性を確保し、かつ軽量化を図るため、底壁部１４ａとその外内側に一体形成された外側壁部１４ｂ及び内側壁部１４ｃとにより構成され、その内部は横断面がＵ字状の溝部１４ｄとなっている。
【０００４】
又、スポーク部芯金１８も所定の剛性を確保し、かつ軽量化を図るため、底壁部１８ａとその外内側に一体形成された左側壁部１８ｂ及び右側壁部１８ｃとにより構成され、その内部は横断面がＵ字状の溝部１８ｄとなっている。
【０００５】
【発明が解決しようとする課題】
ところが、従来のステアリングホイールの芯金は、鋳造性と剛性のバランスを図るためリング部芯金１４の溝部１４ｄにノックピン等の座を設けるには制約があるので、ノックピン等の座は設けられておらず、全周にわたって横断面の形状及び断面積がほぼ一定になるように構成されていた。このため、溝部１４ｄを構成する底壁部１４ａ、外側壁部１４ｂ及び内側壁部１４ｃの肉厚が大きく設定され、リング部芯金１４の重量が増大するという問題があった。
【０００６】
一方、スポーク部芯金１８は、該芯金１８とリング部芯金１４との第１及び第２の連結部３１、３２において、鋳造時にアルミニウム合金の溶湯がスポーク部芯金１８から矢印で示すようにリング部芯金１４に流れ易くするため、溝部１８ｄのみが形成されていた。このため、前記連結部３１、３２の捻り剛性が低下し、それを確保するため底壁部１８ａ、左側壁部１８ｂ、右側壁部１８ｃの肉厚を大きくしなければならず、スポーク部芯金１８の重量が増大するという問題があった。
【０００７】
前述した連結部３１、３２における捻り剛性が低いと、自動車のアイドリング運転時に連結部３１、３２を中心にリング部芯金１４が振動し易く、この振動により連結部３１、３２が金属疲労して亀裂が生じ、耐久性が低下するので、それを回避するためにも肉厚を増大する必要があった。
【０００８】
本発明の第１の目的は、上記従来の問題点を解消して、芯金としての所定の剛性を確保しつつ、軽量化を図ることができるステアリングホイールの芯金を提供することにある。
【０００９】
本発明の第２の目的は、上記第１の目的に加えて、スポーク部芯金とリング部芯金の連結部における捻り剛性を向上することができるステアリングホイールの芯金を提供することにある。
【００１０】
【課題を解決するための手段】
上記問題点を解決するために、請求項１に記載の発明は、横断面がＵ字状の溝部を備えたリング部芯金と、上記リング部芯金の中心部に位置してステアリングシャフトに取り付けられるボス部と、前記ボス部とリング部芯金の間に連結され、かつ操舵基準状態において左右方向に延びる第１及び第２のスポーク部芯金と、同じく前記ボス部とリング部芯金の間に連結され、かつ操舵基準状態において運転席側から中心方向に傾斜状態で延びる第３及び第４のスポーク部芯金とを備えたステアリングホイールの芯金において、前記リング部芯金と第１〜第４のスポーク部芯金との第１〜第４の連結部により区画される運転席と反対側の長円弧部、運転席側の中円弧部及び運転席寄りの左右一対の短円弧部のうち、少なくとも前記左右一対の短円弧部に小径部をそれぞれ設けたことを要旨とする。
【００１１】
請求項２に記載の発明は、横断面がＵ字状の溝部を備えたリング部芯金と、上記リング部芯金の中心部に位置してステアリングシャフトに取り付けられるボス部と、前記ボス部とリング部芯金の間に連結され、かつ操舵基準状態において左右方向に延びる第１及び第２のスポーク部芯金と、同じく前記ボス部とリング部芯金の間に連結され、かつ操舵基準状態において運転席側から中心方向に延びる第３のスポーク部芯金とを備えたステアリングホイールの芯金において、前記リング部芯金と第１〜第３のスポーク部芯金の第１〜第３の連結部により区画される運転席と反対側の長円弧部、運転席側の左右一対の短円弧部のうち、少なくとも前記左右一対の短円弧部に小径部をそれぞれ設けたことを要旨とする。
【００１２】
請求項３に記載の発明は、請求項１又は２において、前記小径部は前記外側壁部及び内側壁部の外周縁部にそれぞれ形成された扁平凹状部により形成されていることを要旨とする。
【００１３】
請求項４に記載の発明は、請求項３において、前記四つの円弧部又は三つの円弧部には第１〜第４の小径部又は第１〜第３の小径部が形成され、前記長円弧部の外側壁部に形成された扁平凹状部のリング部芯金の中心に関する形成角は、前記内側壁部に形成された扁平凹状部の形成角よりも大きく設定され、中円弧部及び両短円弧部又は両短円弧部の外側壁部に形成された扁平凹状部の前記中心に関する形成角は、前記内側壁部にそれぞれ形成された扁平凹状部の形成角よりも大きく、かつ中円弧部及び両短円弧部のほぼ全域又は両短円弧部のほぼ全域にわたって設定されていることを要旨とする。
【００１４】
請求項５に記載の発明は、請求項３において、前記中円弧部及び両短円弧部の横断面積又は両短円弧部の横断面積は、前記長円弧部の横断面積よりも小さく設定されていることを要旨とする。
【００１５】
請求項６に記載の発明は、請求項１又は２において、前記小径部の溝部には補強リブが設けられていることを要旨とする。
【００１６】
請求項７に記載の発明は、請求項６において、前記補強リブは成形装置のノックピンの受け座を兼用するものであることを要旨とする。
請求項８に記載の発明は、請求項１又は２において、前記長円弧部の両基端部の溝部には補強ブロック部が設けられていることを要旨とする。
【００１７】
請求項９に記載の発明は、請求項１又は２において、前記左右方向に延びる第１及び第２のスポーク部芯金は、底壁部及び左右両側壁部により横断面が扁平Ｕ字状に成形され、両スポーク部芯金とリング部芯金との第１及び第２の連結部寄りの両スポーク部芯金の両側壁部には補強リブが形成され、該補強リブと、リング部芯金の内側壁部との間に箱状リブが形成されていることを要旨とする。
【００１８】
【発明の実施の形態】
以下、本発明のステアリングホイールの芯金を具体化した一実施形態を図１〜図１２に従って説明する。
【００１９】
図３に示すように、ステアリングホイール１１を構成するアルミニウム合金製の芯金１２の外周部には、リング部１３が設けられている。このリング部１３はリング部芯金１４と、その外周に型成形法により成形された軟質合成樹脂（例えば発泡ウレタン）製の被覆体１５とにより構成されている。前記リング部１３には複数のスポーク部１６〜１６が連結されている。各スポーク部１６〜１６は、前記リング部芯金１４に連結された第１〜第４のスポーク部芯金１７〜２０と、それらの外周部に対し前記被覆体１５の型成形と同時に成形された被覆体１５ａとにより構成されている。前記各スポーク部芯金１７〜２０の内端部は、ボス部２１ａを備えた連結芯金２０により一体的に連結されている。前記ボス部２１ａ内にステアリングシャフト２２が貫通され、ナット２３によりステアリングシャフト２２に芯金１２が固定される。
【００２０】
図１は芯金１２を上下逆にした斜視図であり、図２はその部分拡大斜視図である。図１に示すように前記第１のスポーク部芯金１７と第３のスポーク部芯金１９の間及び第２のスポーク部芯金１８と第４のスポーク部芯金２０の間には、連結バー２４がそれぞれ連結されている。両連結バー２４には取付板２４ａがそれぞれ設けられ、図３に示すステアリングホイール１１の中央部に収容されたパッド部２５を図示しないボルトにより締め付け固定している。なお、前記芯金１２の下部にはカバー２６が装着されている。
【００２１】
次に、リング部芯金１４の構造を図１、２、４を中心に説明する。
リング部芯金１４は剛性を確保し、軽量化を図るためほぼ全周にわたって横断面がＵ字状に形成されている。すなわち、円環状の底壁部１４ａと、その外周及び内周に一体形成された外側壁部１４ｂ及び内側壁部１４ｃによりＵ字状に形成され、その内部空間は溝部１４ｄとなっている。
【００２２】
図４は芯金１２を操舵基準状態において裏側からみた裏面図である。同図に示すように、リング部芯金１４と第１〜第４のスポーク部芯金１７〜２０とは、第１〜第４連結部３１、３２、３３、３４により一体的に連結されている。この実施形態では、操舵基準状態において、運転席と反対側に位置し、かつ前記第１連結部３１及び第２連結部３２の間に位置するほぼ半円弧状のリング部芯金１４を長円弧部１４ｅとし、運転席側に位置し、かつ第３連結部３３と第４連結部３４との間に位置する円弧状のリング部芯金１４を中円弧部１４ｆとし、第１連結部３１と第３連結部３３及び第２連結部３２と第４連結部３４の間の左右一対の円弧状のリング部芯金１４を短円弧部１４ｇ、１４ｇとする。
【００２３】
前記長円弧部１４ｅの中央部には第１小径部１４ｈが形成され、左側の短円弧部１４ｇには第２小径部１４ｉが形成され、右側の短円弧部１４ｇには第３小径部１４ｊが形成され、さらに中円弧部１４ｆには第４小径部１４ｋが形成されている。
【００２４】
前記溝部１４ｄには前記各小径部１４ｈ〜１４ｋと対応するように、補強リブ１４ｌがそれぞれ一体に形成されている。又、それ以外の溝部１４ｄにも補強リブ１４ｌが所定のピッチ（例えば５ｃｍ〜１０ｃｍ）で一体に形成されている。各補強リブ１４ｌは芯金１２の型成形時において、ノックピン受け座１４ｍの機能を兼用する。
【００２５】
前記長円弧部１４ｅの左右両側基端部には、溝部１４ｄを埋めるようにして、長円弧部１４ｅの左右両側の基端部における捻り剛性を向上するための補強ブロック部１４ｎ、１４ｎが一体に成形されている。
【００２６】
前記第１小径部１４ｈは、外側壁部１４ｂ及び内側壁部１４ｃの上端縁にそれぞれ扁平凹状部１４ｑを芯金１２の型成形時に成形することにより形成されている。前記扁平凹状部１４ｑは、両端部において滑らかに傾斜するように形成された傾斜面１４ｏ、１４ｏと、両傾斜面１４ｏ、１４ｏに滑らかに接続される水平面１４ｐとにより形成されている。前記第１小径部１４ｈの外側壁部１４ｂ側の扁平凹状部１４ｑのボス部２１ａの中心Ｏに関する形成角α１は、ほぼ１００度に設定され、内側壁部１４ｃの扁平凹状部１４ｑの前記形成角α１と同じ形成角β１は、ほぼ３０度に設定されている。
【００２７】
前記第２〜第４の小径部１４ｉ〜１４ｋの内側壁部１４ｃ側の扁平凹状部１４ｑの形成角β２、β３、β４は、それぞれほぼ３０度に設定され、外側壁部１４ｂ側の扁平凹状部１４ｑの形成角α２は、中円弧部１４ｆ及び短円弧部１４ｇ、１４ｇのほぼ全域にわたって約１７０度に設定されている。
【００２８】
図４に示すように、外側壁部１４ｂの扁平凹状部１４ｑの形成角α２とほぼ同じ領域においては、前記中円弧部１４ｆ及び短円弧部１４ｇの横断面積は、前記長円弧部１４ｅの横断面積よりも小さく設定されている。すなわち、図４の１−１線〜３−３線における断面を表す図５〜図７に示すように、長円弧部１４ｅの横断面積よりも、図４の４−４線〜７−７線における断面を表す図８〜図１１に示すように、中円弧部１４ｆ及び短円弧部１４ｇの横断面積が小さく設定されている。この理由は、中円弧部１４ｆと短円弧部１４ｇ側に第３及び第４のスポーク部芯金１９、２０が存在するので、長円弧部１４ｅの剛性と、中円弧部１４ｆ及び短円弧部１４ｇの剛性とのバランスを適正にするためである。
【００２９】
前記第１及び第２のスポーク部芯金１７、１８は同様に構成されているので、第２のスポーク部芯金１８側の構成について説明し、第１のスポーク部芯金１７は符号１７ａ〜１７ｆを付して説明を省略する。
【００３０】
図１及び図２に示すように、スポーク部芯金１８は、剛性を確保し、かつ軽量化を図るため、底壁部１８ａとその左右両側の側壁部１８ｂ、１８ｃとにより扁平Ｕ字状に形成され、内部に溝部１８ｄが形成されている。リング部芯金１４とスポーク部芯金１８の第２連結部３２付近において、前記溝部１８ｄには補強リブ１８ｅが一体に形成され、該補強リブ１８ｅ、両側壁部１８ｂ、１８ｃ及びリング部芯金１４の内側壁部１４ｃにより箱状リブ１８ｆが形成されている。
【００３１】
前記のように構成した芯金１２は、型成形装置のキャビティ内に例えばアルミニウム合金の溶湯を注入することにより成形される。この溶湯の注入はボス部２１ａ側から行われる。すなわち、図１に示す芯金１２がキャビティと想定すると、溶湯は連結芯金２１及びボス部２１ａの成形用キャビティから各スポーク部芯金１７〜１０のキャビティを矢印で示すように流れる。そして、第１〜第４のスポーク部芯金１７〜２０の成形用キャビティの下端部において、さらに水平方向に、かつリング部芯金１４の成形用キャビティ内で反対方向に分流する。その後、第１〜第４の小径部１４ｈ〜１４ｋの中央部に向かって溶湯が流動し、各中央部においてそれぞれ互いに融合される。
【００３２】
図１２は右側の短円弧部１４ｇ付近の型成形装置を示す部分断面図である。この図５に示すように、下型４１と上型４２はその型合わせ面において、上下に分離可能に接合され、上型４２にはノックピン４３が装着されている。短円弧部１４ｇには第３小径部１４ｊが設けられているので、その第３小径部１４ｊの中間部に向かって矢印で示すように互いに接近する方向に流動する溶湯は、その速度が速められた状態で補強リブ１４ｌにおいて融合され、この補強リブ１４ｌが融合部１４ｒとなる。
【００３３】
なお、キャビティ内の溶湯が凝固点温度以下に低下した後、下型４１と上型４２を離隔すると、芯金１２は上型４２とともに上昇する。そして、ノックピン４３を下方に移動すると、芯金１２が上型４２のキャビティから離れ、芯金１２の製造が終了する。
【００３４】
次に、前記のように構成したステアリングホイール１１の芯金１２について、その効果を構成とともに列記する。
（１）前記実施形態では、前記リング部芯金１４の複数箇所に第１〜第４の小径部１４ｈ〜１４ｋを設け、前記各小径部の溝部１４ｄに補強リブ１４ｌをそれぞれ設けたので、リング部芯金１４の剛性を所定値に確保しつつリング部芯金１４を軽量化することができる。
【００３５】
（２）前記実施形態では、第１〜第４のスポーク部芯金１７〜２０を備えたステアリングホイールの芯金１２において、リング部芯金１４の少なくとも左右一対の短円弧部１４ｇに小径部１４ｉ、１４ｊを設け、小径部１４ｉ、１４ｊの溝部１４ｄに補強リブ１４ｌを設けた。このため、両短円弧部１４ｇの剛性を所定値に確保しつつ、短円弧部１４ｇの軽量化を図ることができる。特に、両短円弧部１４ｇ、１４ｇは一対のスポーク部芯金１７、１９及び１８、２０間に位置しているので、長円弧部１４ｅ及び中円弧部１４ｆの剛性と同様に保持しなくてもよく、従って、リング部芯金１４の軽量化を適正に行うことができる。
【００３６】
（３）前記実施形態では、溝部１４ｄに設けた補強リブ１４ｌが成形装置のノックピン４３の受け座１４ｍを兼用しているので、型成形された後に、芯金１２をキャビティからノックピン４３により容易に分離することができる。
【００３７】
（４）前記実施形態では、第１〜第４の小径部１４ｈ〜１４ｋの中間部に補強リブ１４ｌを設けたので、型成形時において、互いに反対方向から合流するように流動する溶湯が体積の大きい補強リブ１４ｌの成形用キャビティにおいて融合し、融合部１４ｒの結合強度を向上することができる。
【００３８】
（５）前記実施形態では、スポーク部芯金１８を、横断面が扁平逆Ｕ字状になるように成形し、スポーク部芯金１８とリング部芯金１４との第１及び第２の連結部３１、３２寄りのスポーク部芯金１７、１８の溝部１７ｄ、１８ｄに対し補強リブ１７ｅ、１８ｅを形成し、該補強リブ１７ｅ、１８ｅとリング部芯金１４との間に箱状リブ１７ｆ、１８ｆを形成した。このため、リング部芯金１４に外力が作用した場合に、第１及び第２の連結部３１、３２におけるスポーク部芯金１７、１８の捻り剛性を向上することができる。そして、剛性を向上することができる分、スポーク部芯金１７、１８を小径化して軽量化することができる。
【００３９】
（６）前記実施形態では、第１〜第４の小径部１４ｈ〜１４ｋと対応する外側壁部１４ｂ及び内側壁部１４ｃに傾斜面１４ｏを設けた。このため、型成形時に溶湯が小径部１４ｈ〜１４ｋの中間部に向かって流れる際に、その通路断面積が小さくなるにつれて流速が速くなり、リング部芯金１４の鋳造性（一般に通路面積が小さくなると溶湯が冷え易く鋳造性が低下する）を低下させることなく適正に芯金１２を成形することができる。
【００４０】
（７）前記実施形態では、図４に示すように、外側壁部１４ｂ側の扁平凹状部１４ｑの形成角α１を、内側壁部１４ｃ側の扁平凹状部１４ｑの形成角β１よりも大きく設定した。このため、外側壁部１４ｂ及び内側壁部１４ｃに同じ形成角の扁平凹状部１４ｑを形成するのと比較して、長円弧部１４ｅの軽量化を効率的に行うことができる。
【００４１】
（８）前記実施形態では、図４に示すように、第２〜第４の小径部１４ｉ〜１４ｋと対応する内側壁部１４ｃ側の扁平凹状部１４ｑをそれぞれ独立して形成角β２〜β４に設定し、外側壁部１４ｂの扁平凹状部１４ｑの形成角α２を第２〜第４の小径部１４ｉ〜１４ｋを含むように大きく設定した。このため、外側壁部１４ｂ及び内側壁部１４ｃに形成角β２〜β４と同じ形成角の扁平凹状部１４ｑを形成するのと比較して、中円弧部１４ｆ及び短円弧部１４ｇの軽量化を効率的に行うことができる。
【００４２】
（９）前記実施形態では、長円弧部１４ｅの左右両側の基端部に補強ブロック部１４ｎ、１４ｎを形成したので、長円弧部１４ｅに作用する外力（図２の矢印Ｑ参照）による捻り剛性（図２の矢印Ｐ参照）を向上することができる。
【００４３】
（１０）前記実施形態では、外側壁部１４ｂの扁平凹状部１４ｑの形成角α２とほぼ同じ領域において、前記中円弧部１４ｆ及び短円弧部１４ｇの横断面積を、前記長円弧部１４ｅの横断面積よりも小さく設定した。このため、長円弧部１４ｅと中円弧部１４ｆ及び短円弧部１４ｇの剛性のバランスを実現し、リング部芯金１４の軽量化を図ることができる。
【００４４】
前記実施形態の芯金１２は、前述した（７）〜（１０）の構成に基づく特有の効果を奏するが、リング部芯金１４及びスポーク部芯金１７〜２０に求められる剛性上の要件は、解析シミュレーションの一つである有限要素法（ＦＥＭ；
Ｆinite Ｅlemente Ｍethod ）を活用して満足していることが確認できた。そして、従来のステアリングホイールの芯金と前記実施形態のステアリングホイールの芯金１２とを比較したところ、重量が約２００グラム軽減され、全重量に対し約２０％軽減することができた。
【００４５】
なお、上記実施形態は以下のように変更してもよい。
○ 図１３に示すように、スポーク部芯金１７、１８、１９Ａが全部で三本のいわゆる三芯タイプのステアリングホイール１１の芯金１２に具体化してもよい。
【００４６】
この実施形態では、芯金１２は前記ボス部２１ａとリング部芯金１４の間に連結され、かつ操舵基準状態において左右方向に延びる一対のスポーク部芯金１７、１８と、同じく前記ボス部２１ａとリング部芯金１４の間に連結され、かつ操舵基準状態において運転席側から中心方向に、かつ前後方向に延びる一本のスポーク部芯金１９Ａとを備えている。
【００４７】
上記の実施形態において、前記実施形態と同様の機能を有する部材については、同一の符号を付して説明を省略した。この実施形態では、前記実施形態の四芯タイプの芯金１２の効果（１）〜（１０）とほぼ同様の効果を奏する。
【００４８】
○ 前記実施形態では、扁平凹状部１４ｑのボス部２１ａの中心Ｏに関する形成角α１、β１、α２、β２、β３、β４を外側壁部１４ｂと内側壁部１４ｃで相違させたが、両形成角を内側壁部１４ｃ側の形成角に合わるようにしてもよい。この場合には形成角β１、β２、β３、β４を例えば３０度〜９０度の範囲で大きく設定してもよい。
【００４９】
○ 前記実施形態では、溶湯が互いに融合する融合部１４ｒに補強リブ１４ｌを設けたが、この位置を非融合部に変更してもよい。
○ 前記実施形態では、補強リブ１４ｌにノックピン受け座１４ｍとしての機能を兼用させたが、兼用しないようにしてもよい。
【００５０】
○ 前記実施形態の補強リブ１４ｌ、１７ｅ、１８ｅを省略してもよい。
○ 前記リング部芯金１４に設けた小径部１４ｈ〜１４ｋとして、扁平凹状部１４ｑを形成しないでＵ字状の溝部１４ｄの形状をそのまま縮小したものとしてもよい。
【００５１】
以下に、この発明と関連した技術について説明する。
この関連技術では、前記リング部芯金１４の構成は、従来のリング部芯金１４の構成と同一とし、第１及び第２のスポーク部芯金１７、１８の構成を前述した実施形態と同一の構成としている。又、リング部芯金１４に補強ブロック部１４ｎを設けている。
【００５２】
上記の関連技術からは、以下の技術思想が把握できる。
（技術思想１）
横断面が逆Ｕ字状の溝部１４ｄを備えたリング部芯金１４と、
上記リング部芯金１４の中心部に位置してステアリングシャフト２２に取り付けられるボス部２１ａと、
前記ボス部２１ａとリング部芯金１４の間に連結され、かつ操舵基準状態において左右方向に延びる第１及び第２のスポーク部芯金１７、１８と、
同じく前記ボス部２１ａとリング部芯金１４の間に連結され、かつ操舵基準状態において運転席側から中心方向に延びる中央部のスポーク部芯金１９Ａ又は左右一対のスポーク部芯金１９、２０と
を備えたステアリングホイールの芯金１２において、
前記左右方向に延びる一対のスポーク部芯金１７、１８は、横断面が扁平逆Ｕ字状に成形され、両スポーク部芯金１７、１８とリング部芯金１４との第１及び第２の連結部３１、３２寄りの一対のスポーク部芯金１７、１８の溝部１７ｄ、１８ｄには補強リブ１７ｅ、１８ｅが形成され、該補強リブ１７ｅ、１８ｅとリング部芯金１４との間に箱状リブ１７ｆ、１８ｆが形成されているステアリングホイールの芯金。
【００５３】
従って、技術思想１によれば、スポーク部芯金１７、１８の捻り剛性を向上することができるとともに、スポーク部芯金１７、１８を小径化して軽量化を図ることができる。
【００５４】
（技術思想２）
上記技術思想１において、長円弧部１４ｅの左右両側基端部の溝部１４ｄに補強ブロック部１４ｎ、１４ｎを一体に成形したステアリングホイールの芯金。
【００５５】
上記の技術思想２によれば、長円弧部１４ｅの基端部における捻り剛性を向上することができる。
【００５６】
【発明の効果】
以上詳述したように、請求項１〜９記載の発明は、リング部芯金の所定の剛性を確保し、その軽量化を図ることができる。
【００５７】
請求項１又は２記載の発明は、リング部芯金の短円弧部の所定の剛性を確保し、その軽量化を図ることができる。
請求項３記載の発明は、外側壁部及び内側壁部の外縁部に扁平凹状部を形成することにより小径部を容易に形成することができる。
【００５８】
請求項４記載の発明は、外側壁部に設けた扁平凹状部の形成角は、内側壁部に形成された扁平凹状部の形成角よりも大きく設定されているので、リング部芯金の軽量化を効率良く行うことができる。
【００５９】
請求項５記載の発明は、操舵基準状態において運転席側の中円弧部及び両短円弧部の横断面積又は両短円弧部の横断面積は、運転席と反対側の長円弧部の横断面積よりも小さく設定されているので、剛性のバランスを適正に保持し、リング部芯金の軽量化を効率的に行うことができる。
【００６０】
請求項６記載の発明は、小径部の溝部に補強リブが設けられているので、所定の剛性を確保し、軽量化を図ることができる。
請求項７記載の発明は、補強リブが成形装置のノックピンの受け座を兼用するので、成形後の製品の取り出しを容易に行うことができる。
【００６１】
請求項８記載の発明は、長円弧部の基端部の溝部に補強ブロック部が設けられているので、長円弧部の左右の基端部における捻り剛性を向上することができる。
【００６２】
請求項９記載の発明は、左右方向に延びる第１及び第２のスポーク部芯金に補強リブが形成され、該補強リブと、リング部芯金の内側壁部との間に箱状リブが形成されているので、第１及び第２のスポーク部芯金とリング部芯金の連結部の捻り剛性を向上し、剛性を一定に保持した場合には、スポーク部芯金の軽量化を図ることができる。
【図面の簡単な説明】
【図１】この発明のステアリングホイールの芯金を裏側から見た状態を示す斜視図。
【図２】芯金の要部を示す拡大斜視図。
【図３】ステアリングホイールの縦断面図。
【図４】芯金の裏面図。
【図５】図４の１−１線におけるリング部芯金の拡大断面図。
【図６】図４の２−２線におけるリング部芯金の拡大断面図。
【図７】図４の３−３線におけるリング部芯金の拡大断面図。
【図８】図４の４−４線におけるリング部芯金の拡大断面図。
【図９】図４の５−５線におけるリング部芯金の拡大断面図。
【図１０】図４の６−６線におけるリング部芯金の拡大断面図。
【図１１】図４の７−７線におけるリング部芯金の拡大断面図。
【図１２】リング部芯金の成形方法を説明する部分断面図。
【図１３】芯金の別例を示す裏面図。
【図１４】従来のステアリングホイールの芯金の斜視図。
【符号の説明】
α１，α２，β１〜β４…形成角、１２…芯金、１４… リング部芯金、１４ａ…底壁部、１４ｂ…外側壁部、１４ｃ…内側壁部、１４ｄ…溝部、１４ｅ…長円弧部、１４ｆ…中円弧部、１４ｇ…短円弧部、１４ｌ…補強リブ、１４ｍ…受け座、１４ｎ…補強ブロック部、１４ｑ…扁平凹状部、１４ｈ〜１４ｋ…第１〜第４の小径部、１７〜２０…第１〜第４のスポーク部芯金、１９Ａ…第３のスポーク部芯金、２１ａ…ボス部、２２…ステアリングシャフト、３１〜３４…第１〜第４の連結部、４３…ノックピン。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mandrel of a steering wheel, and more particularly to a mandrel of a steering wheel that can reduce the weight while ensuring the necessary rigidity of a ring core.
[0002]
[Prior art]
In general, a steering wheel has a metal core inside thereof in order to ensure a predetermined rigidity. This metal core will be described with reference to FIG. FIG. 14 is a perspective view of the core bar upside down. This metal core is a ring core metal 14, four spoke metal cores 17 to 20 connected to the inside thereof, and a boss integrally formed with a connection metal core 21 that connects each spoke metal core 17 to 20. It is comprised by the part 21a.
[0003]
The ring cored bar 14 has a bottom wall part 14a and an outer wall part 14b and an inner wall part 14c integrally formed on the outer and inner sides in order to ensure a predetermined rigidity and reduce the weight. Has a U-shaped groove portion 14d.
[0004]
In addition, the spoke cored bar 18 also includes a bottom wall part 18a and a left side wall part 18b and a right side wall part 18c that are integrally formed on the outer and inner sides in order to ensure a predetermined rigidity and reduce the weight. The inside is a groove portion 18d having a U-shaped cross section.
[0005]
[Problems to be solved by the invention]
However, since the core of the conventional steering wheel has a restriction in providing a seat such as a knock pin in the groove 14d of the ring core 14 in order to balance castability and rigidity, the seat such as a knock pin is provided. In other words, the cross-sectional shape and cross-sectional area are almost constant over the entire circumference. For this reason, there is a problem that the thickness of the bottom wall portion 14a, the outer wall portion 14b, and the inner wall portion 14c constituting the groove portion 14d is set large, and the weight of the ring core metal 14 is increased.
[0006]
On the other hand, the spoke core metal 18 is shown by an arrow from the spoke core metal 18 at the first and second connecting portions 31 and 32 between the core metal 18 and the ring core metal 14 at the time of casting. In order to facilitate the flow to the ring core 14, only the groove 18 d is formed. For this reason, the torsional rigidity of the connecting portions 31 and 32 is lowered, and in order to secure it, the thickness of the bottom wall portion 18a, the left side wall portion 18b, and the right side wall portion 18c must be increased. There was a problem that the weight of 18 increased.
[0007]
If the torsional rigidity in the connecting portions 31 and 32 is low, the ring core metal 14 easily vibrates around the connecting portions 31 and 32 during the idling operation of the automobile, and this connection causes the connecting portions 31 and 32 to be fatigued by metal. Since cracks occur and durability deteriorates, it was necessary to increase the wall thickness in order to avoid them.
[0008]
A first object of the present invention is to provide a steering wheel core bar that can reduce the weight while eliminating the above-mentioned conventional problems and ensuring a predetermined rigidity as the core bar.
[0009]
In addition to the first object, a second object of the present invention is to provide a metal core for a steering wheel that can improve the torsional rigidity at the connecting portion between the spoke metal core and the ring metal core. .
[0010]
[Means for Solving the Problems]
  In order to solve the above problem, the invention according to claim 1A ring cored bar having a U-shaped cross section, a boss positioned at the center of the ring cored bar and attached to the steering shaft, and connected between the boss and the ring cored bar. And the first and second spoke cores extending in the left-right direction in the steering reference state, and also connected between the boss portion and the ring core, and in the steering reference state from the driver seat side toward the center. In a steering wheel core metal including third and fourth spoke metal cores extending in an inclined state, the first to fourth couplings of the ring metal core and the first to fourth spoke metal cores. A small-diameter portion is provided on at least the pair of left and right short arc portions among the long arc portion on the side opposite to the driver seat divided by the portion, the middle arc portion on the driver seat side, and the pair of left and right short arc portions near the driver seat. TheThis is the gist.
[0011]
  The invention described in claim 2A ring cored bar having a U-shaped cross section, a boss positioned at the center of the ring cored bar and attached to the steering shaft, and connected between the boss and the ring cored bar. And the first and second spoke cores extending in the left-right direction in the steering reference state, and also connected between the boss portion and the ring core, and in the steering reference state from the driver seat side toward the center. In a steering wheel core metal having a third spoke core metal bar that extends, a driver's seat is defined by the ring core metal and the first to third connecting parts of the first to third spoke metal cores. A small-diameter portion is provided on at least the pair of left and right short arc portions among the long arc portion on the opposite side and the pair of left and right short arc portions on the driver's seat side.This is the gist.
[0012]
  The invention according to claim 3In Claim 1 or 2, the said small diameter part is formed of the flat concave part formed in the outer-periphery edge part of the said outer side wall part and an inner wall part, respectively.This is the gist.
[0013]
  The invention according to claim 4In Claim 3, the said 1st-4th small diameter part or the 1st-3rd small diameter part was formed in the said 4 circular arc part or three circular arc parts, and it was formed in the outer wall part of the said long circular arc part. The formation angle of the center of the ring-shaped cored bar of the flat concave part is set to be larger than the formation angle of the flat concave part formed on the inner wall part, and the outside of the middle arc part and both short arc parts or both short arc parts The angle of formation of the flat concave portion formed on the wall portion with respect to the center is larger than the angle of formation of the flat concave portion formed on the inner wall portion, respectively, and substantially the entire or both of the middle arc portion and the short arc portions. Set over almost the entire short arcThis is the gist.
[0014]
  The invention described in claim 5In Claim 3, the cross-sectional area of the said middle circular arc part and both short arc parts, or the cross-sectional area of both short arc parts is set smaller than the cross-sectional area of the said long arc part.This is the gist.
[0015]
  The invention described in claim 63. A reinforcing rib is provided in the groove portion of the small diameter portion according to claim 1 or 2.This is the gist.
[0016]
  The invention described in claim 77. The reinforcing rib according to claim 6, which also serves as a receiving seat for a knock pin of a molding apparatus.This is the gist.
  The invention according to claim 8 provides:In Claim 1 or 2, the reinforcement block part is provided in the groove part of the both base end parts of the said long circular arc part.This is the gist.
[0017]
  The invention according to claim 9 is:3. The first and second spoke cores extending in the left-right direction according to claim 1, wherein the cross section is formed into a flat U-shape by the bottom wall part and the left and right side wall parts. Reinforcing ribs are formed on both side walls of the spoke cores close to the first and second connecting portions with the ring core, and between the reinforcing ribs and the inner wall of the ring core. Box-shaped ribs are formedThe gist.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the core of the steering wheel of the present invention is embodied will be described with reference to FIGS.
[0019]
As shown in FIG. 3, a ring portion 13 is provided on the outer periphery of an aluminum alloy cored bar 12 that constitutes the steering wheel 11. The ring portion 13 is composed of a ring cored bar 14 and a cover 15 made of a soft synthetic resin (for example, urethane foam) formed on the outer periphery thereof by a molding method. A plurality of spoke parts 16 to 16 are connected to the ring part 13. Each spoke part 16-16 is shape | molded simultaneously with the shaping | molding of the said covering 15 with respect to the 1st-4th spoke part metal cores 17-20 connected with the said ring part metal core 14, and those outer peripheral parts. And the covering 15a. The inner ends of the spoke part cores 17 to 20 are integrally connected by a connection core bar 20 provided with a boss part 21a. A steering shaft 22 is passed through the boss portion 21 a, and the core metal 12 is fixed to the steering shaft 22 by a nut 23.
[0020]
FIG. 1 is a perspective view of the cored bar 12 upside down, and FIG. 2 is a partially enlarged perspective view thereof. As shown in FIG. 1, there is a connection between the first spoke core metal 17 and the third spoke core metal 19 and between the second spoke core metal 18 and the fourth spoke core metal 20. Bars 24 are connected to each other. Each of the connecting bars 24 is provided with a mounting plate 24a, and a pad portion 25 accommodated in the central portion of the steering wheel 11 shown in FIG. A cover 26 is attached to the lower part of the cored bar 12.
[0021]
Next, the structure of the ring core 14 will be described with reference to FIGS.
The ring cored bar 14 has a U-shaped cross section over substantially the entire circumference in order to ensure rigidity and reduce weight. That is, it is formed in a U shape by an annular bottom wall portion 14a, an outer wall portion 14b and an inner wall portion 14c that are integrally formed on the outer periphery and inner periphery thereof, and the inner space is a groove portion 14d.
[0022]
FIG. 4 is a back view of the cored bar 12 viewed from the back side in the steering reference state. As shown in the figure, the ring core 14 and the first to fourth spoke cores 17 to 20 are integrally connected by the first to fourth connecting portions 31, 32, 33, and 34. Yes. In this embodiment, in the steering reference state, the ring-shaped cored bar 14 that is located on the side opposite to the driver's seat and located between the first connecting portion 31 and the second connecting portion 32 is a long arc. The ring-shaped cored bar 14 located on the driver's seat side and located between the third connecting part 33 and the fourth connecting part 34 is defined as a middle arc part 14f, and the first connecting part 31 A pair of left and right arc-shaped ring cores 14 between the third connecting portion 33 and the second connecting portion 32 and the fourth connecting portion 34 are referred to as short arc portions 14g and 14g.
[0023]
A first small diameter portion 14h is formed at the center of the long arc portion 14e, a second small diameter portion 14i is formed at the left short arc portion 14g, and a third small diameter portion 14j is formed at the right short arc portion 14g. Further, a fourth small diameter portion 14k is formed in the middle arc portion 14f.
[0024]
Reinforcing ribs 141 are integrally formed in the groove portion 14d so as to correspond to the respective small diameter portions 14h to 14k. Further, reinforcing ribs 141 are integrally formed at a predetermined pitch (for example, 5 cm to 10 cm) in the other groove portion 14d. Each reinforcing rib 14l also functions as a knock pin receiving seat 14m when the core bar 12 is molded.
[0025]
Reinforcing block portions 14n and 14n for improving torsional rigidity at the left and right base end portions of the long arc portion 14e are integrally formed at the left and right base end portions of the long arc portion 14e so as to fill the groove portion 14d. Molded.
[0026]
The first small diameter portion 14h is formed by molding a flat concave portion 14q at the upper end edge of the outer wall portion 14b and the inner wall portion 14c, respectively, when the cored bar 12 is molded. The flat concave portion 14q is formed by inclined surfaces 14o, 14o formed so as to be smoothly inclined at both ends, and a horizontal plane 14p smoothly connected to both inclined surfaces 14o, 14o. The formation angle α1 related to the center O of the boss portion 21a of the flat concave portion 14q on the outer wall portion 14b side of the first small diameter portion 14h is set to approximately 100 degrees, and the formation angle of the flat concave portion 14q of the inner wall portion 14c is set. The same formation angle β1 as α1 is set to approximately 30 degrees.
[0027]
The formation angles β2, β3, β4 of the flat concave portion 14q on the inner wall portion 14c side of the second to fourth small diameter portions 14i-14k are respectively set to approximately 30 degrees, and the flat concave portion on the outer wall portion 14b side. The formation angle α2 of 14q is set to about 170 degrees over almost the entire area of the middle arc portion 14f and the short arc portions 14g and 14g.
[0028]
As shown in FIG. 4, in the region substantially the same as the formation angle α2 of the flat concave portion 14q of the outer wall portion 14b, the cross-sectional area of the middle arc portion 14f and the short arc portion 14g is the cross-sectional area of the long arc portion 14e. Is set smaller than. That is, as shown in FIGS. 5 to 7 representing cross sections taken along lines 1-1 to 3-3 in FIG. 4, lines 4-4 to 7-7 in FIG. As shown in FIG. 8 to FIG. 11 representing the cross sections, the cross-sectional areas of the middle arc portion 14f and the short arc portion 14g are set small. This is because the third and fourth spoke cores 19 and 20 are present on the side of the middle arc portion 14f and the short arc portion 14g, so that the rigidity of the long arc portion 14e and the middle arc portion 14f and the short arc portion 14g It is for making the balance with the rigidity of the proper.
[0029]
Since the first and second spoke metal cores 17 and 18 are configured in the same manner, the configuration of the second spoke metal core 18 will be described. The first spoke metal core 17 is denoted by reference numerals 17a to 17a. The description is omitted with 17f.
[0030]
As shown in FIGS. 1 and 2, the spoke core metal 18 has a flat U-shape formed by a bottom wall portion 18a and left and right side wall portions 18b and 18c in order to ensure rigidity and reduce weight. The groove 18d is formed inside. In the vicinity of the second connecting portion 32 between the ring core 14 and the spoke core 18, a reinforcing rib 18 e is formed integrally with the groove 18 d, and the reinforcing rib 18 e, both side walls 18 b and 18 c, and the ring core A box-shaped rib 18f is formed by the 14 inner wall portions 14c.
[0031]
The core metal 12 configured as described above is formed by, for example, injecting a molten aluminum alloy into the cavity of the mold forming apparatus. The molten metal is injected from the boss portion 21a side. That is, assuming that the cored bar 12 shown in FIG. 1 is a cavity, the molten metal flows from the forming cores of the connecting cored bar 21 and the boss part 21a to the cavities of the spoke part cored bars 17 to 10 as indicated by arrows. And in the lower end part of the shaping | molding cavity of the 1st-4th spoke part metal cores 17-20, it shunts further in the horizontal direction and in the opposite direction within the shaping | molding cavity of the ring part metal core 14. FIG. Thereafter, the molten metal flows toward the central portion of the first to fourth small diameter portions 14h to 14k and is fused with each other at each central portion.
[0032]
FIG. 12 is a partial cross-sectional view showing the mold forming device near the right short arc portion 14g. As shown in FIG. 5, the lower die 41 and the upper die 42 are joined to each other on the die mating surface so as to be separated in the vertical direction. Since the short arc portion 14g is provided with the third small diameter portion 14j, the speed of the molten metal flowing in the directions approaching each other as shown by the arrows toward the intermediate portion of the third small diameter portion 14j is increased. In this state, the reinforcing ribs 14l are fused, and the reinforcing ribs 14l become the fused portions 14r.
[0033]
When the molten metal in the cavity is lowered below the freezing point temperature and the lower mold 41 and the upper mold 42 are separated from each other, the core metal 12 rises together with the upper mold 42. When the knock pin 43 is moved downward, the cored bar 12 moves away from the cavity of the upper mold 42, and the manufacturing of the cored bar 12 is completed.
[0034]
Next, the effects of the core metal 12 of the steering wheel 11 configured as described above will be listed together with the configuration.
(1) In the above embodiment, since the first to fourth small diameter portions 14h to 14k are provided at a plurality of locations of the ring core metal 14, and the reinforcing ribs 141 are provided to the groove portions 14d of the respective small diameter portions, the ring The ring core metal 14 can be reduced in weight while ensuring the rigidity of the core metal 14 at a predetermined value.
[0035]
(2) In the above embodiment, in the core 12 of the steering wheel provided with the first to fourth spoke cores 17-20, the small diameter portion 14i is formed on at least the pair of left and right short arcs 14g of the ring core 14. 14j, and reinforcing ribs 141 are provided in the grooves 14d of the small diameter portions 14i, 14j. For this reason, weight reduction of the short arc part 14g can be achieved, ensuring the rigidity of both the short arc parts 14g to a predetermined value. In particular, since both the short arc portions 14g and 14g are positioned between the pair of spoke cores 17, 19, 18 and 20, it is not necessary to hold the same as the rigidity of the long arc portion 14e and the middle arc portion 14f. Therefore, the weight of the ring core 14 can be appropriately reduced.
[0036]
(3) In the above embodiment, the reinforcing rib 141 provided in the groove portion 14d also serves as the receiving seat 14m of the knock pin 43 of the molding device, so that the core metal 12 can be easily removed from the cavity by the knock pin 43 after being molded. Can be separated.
[0037]
(4) In the above embodiment, since the reinforcing ribs 141 are provided in the middle portion of the first to fourth small diameter portions 14h to 14k, the molten metal that flows so as to merge from opposite directions at the time of mold forming has a volume. It is possible to improve the bonding strength of the fusion part 14r by fusing in the molding cavity of the large reinforcing rib 14l.
[0038]
(5) In the said embodiment, the spoke part metal core 18 is shape | molded so that a cross section may become a flat reverse U shape, and the 1st and 2nd connection of the spoke part metal core 18 and the ring part metal core 14 is carried out. Reinforcing ribs 17e, 18e are formed on the groove portions 17d, 18d of the spoke cores 17, 18 near the portions 31, 32, and a box-shaped rib 17f, between the reinforcing ribs 17e, 18e and the ring cored bar 14, 18f was formed. For this reason, when external force acts on the ring core metal 14, the torsional rigidity of the spoke metal cores 17 and 18 in the first and second connecting portions 31 and 32 can be improved. And since the rigidity can be improved, the spoke cores 17 and 18 can be reduced in diameter and reduced in weight.
[0039]
(6) In the said embodiment, the inclined surface 14o was provided in the outer side wall part 14b and the inner wall part 14c corresponding to the 1st-4th small diameter parts 14h-14k. For this reason, when the molten metal flows toward the intermediate portion of the small diameter portions 14h to 14k at the time of molding, the flow velocity increases as the passage cross-sectional area decreases, and the castability of the ring core metal 14 (generally the passage area is small). In this case, the cored bar 12 can be appropriately formed without lowering the molten metal that is easy to cool and the castability is reduced.
[0040]
(7) In the above embodiment, as shown in FIG. 4, the formation angle α1 of the flat concave portion 14q on the outer wall portion 14b side is set larger than the formation angle β1 of the flat concave portion 14q on the inner wall portion 14c side. . For this reason, compared with forming the flat concave part 14q of the same formation angle in the outer side wall part 14b and the inner side wall part 14c, the weight reduction of the long circular arc part 14e can be performed efficiently.
[0041]
(8) In the said embodiment, as shown in FIG. 4, the flat concave-shaped part 14q by the side of the inner wall part 14c corresponding to the 2nd-4th small diameter parts 14i-14k is each independently made into formation angle (beta) 2-beta4. The formation angle α2 of the flat concave portion 14q of the outer wall portion 14b was set to be large so as to include the second to fourth small diameter portions 14i to 14k. For this reason, compared with the formation of the flat concave portion 14q having the same formation angle as the formation angles β2 to β4 on the outer wall portion 14b and the inner wall portion 14c, the weight reduction of the middle arc portion 14f and the short arc portion 14g is more efficient. Can be done automatically.
[0042]
(9) In the above embodiment, since the reinforcement block portions 14n and 14n are formed at the left and right base ends of the long arc portion 14e, the torsional rigidity due to the external force (see arrow Q in FIG. 2) acting on the long arc portion 14e. (See arrow P in FIG. 2).
[0043]
(10) In the embodiment, in the region substantially the same as the formation angle α2 of the flat concave portion 14q of the outer wall portion 14b, the cross-sectional area of the middle arc portion 14f and the short arc portion 14g is set to the cross-sectional area of the long arc portion 14e. Was set smaller. For this reason, the rigidity balance of the long circular arc part 14e, the middle circular arc part 14f, and the short circular arc part 14g is implement | achieved, and the weight reduction of the ring core metal 14 can be achieved.
[0044]
The cored bar 12 of the above embodiment has a specific effect based on the above-described configurations (7) to (10), but the rigidity requirements for the ring cored bar 14 and the spoked cored bar 17-20 are as follows. The Finite Element Method (FEM), one of the analytical simulations
We were able to confirm that we were satisfied using Finite Elemente Method). Then, when the metal core of the conventional steering wheel and the metal core 12 of the steering wheel of the above embodiment were compared, the weight was reduced by about 200 grams, and the weight could be reduced by about 20% with respect to the total weight.
[0045]
In addition, you may change the said embodiment as follows.
As shown in FIG. 13, the spoke part cores 17, 18, and 19 </ b> A may be embodied in a total of three so-called three-core type steering wheels 11.
[0046]
In this embodiment, the cored bar 12 is connected between the boss part 21a and the ring part cored bar 14 and extends in the left-right direction in the steering reference state, and also the bossed part 21a. And a ring cored bar 14 and a single spoked cored bar 19A extending in the center direction from the driver's seat side and in the front-rear direction in the steering reference state.
[0047]
In the above embodiment, members having the same functions as those in the above embodiment are given the same reference numerals and description thereof is omitted. In this embodiment, there are substantially the same effects as the effects (1) to (10) of the four-core type cored bar 12 of the above embodiment.
[0048]
In the above embodiment, the formation angles α1, β1, α2, β2, β3, and β4 related to the center O of the boss portion 21a of the flat concave portion 14q are different between the outer wall portion 14b and the inner wall portion 14c. May be adjusted to the forming angle on the inner wall portion 14c side. In this case, the formation angles β1, β2, β3, and β4 may be set large in a range of 30 degrees to 90 degrees, for example.
[0049]
In the above embodiment, the reinforcing ribs 141 are provided in the fusion part 14r where the molten metal is fused together, but this position may be changed to a non-fusion part.
In the above embodiment, the reinforcing rib 14l is also used as the function of the knock pin receiving seat 14m, but it may not be used.
[0050]
(Circle) you may abbreviate | omit the reinforcing ribs 141, 17e, and 18e of the said embodiment.
As the small diameter portions 14h to 14k provided in the ring core metal 14, the shape of the U-shaped groove portion 14d may be reduced as it is without forming the flat concave portion 14q.
[0051]
Hereinafter, techniques related to the present invention will be described.
In this related technology, the configuration of the ring cored bar 14 is the same as that of the conventional ring cored bar 14, and the configurations of the first and second spoke cored bars 17 and 18 are the same as those of the above-described embodiment. The configuration is as follows. Further, a reinforcing block portion 14 n is provided on the ring core metal 14.
[0052]
The following technical idea can be grasped from the above related technology.
(Technology 1)
A ring cored bar 14 having a groove 14d having an inverted U-shaped cross section;
A boss portion 21a attached to the steering shaft 22 at the center of the ring core 14;
First and second spoke cores 17, 18 connected between the boss 21 a and the ring core 14 and extending in the left-right direction in the steering reference state;
Similarly, a central spoke part metal core 19A or a pair of left and right spoke metal cores 19, 20 connected between the boss part 21a and the ring core metal bar 14 and extending in the center direction from the driver's seat in the steering reference state.
In the steering wheel core 12 with
The pair of spoke metal cores 17 and 18 extending in the left-right direction are formed in a flat inverted U shape in cross section, and the first and second spoke metal cores 17 and 18 and the ring metal core 14 are first and second. Reinforcing ribs 17e and 18e are formed in the groove portions 17d and 18d of the pair of spoke cores 17 and 18 near the connecting portions 31 and 32, and a box shape is formed between the reinforcing ribs 17e and 18e and the ring cored bar 14. A metal core for a steering wheel on which ribs 17f and 18f are formed.
[0053]
Therefore, according to the technical idea 1, the torsional rigidity of the spoke cores 17 and 18 can be improved, and the spoke cores 17 and 18 can be reduced in diameter to reduce the weight.
[0054]
(Technology 2)
In the above technical idea 1, the steering wheel core bar in which the reinforcing block portions 14n and 14n are integrally formed in the groove portions 14d at the left and right base ends of the long circular arc portion 14e.
[0055]
According to said technical thought 2, the torsional rigidity in the base end part of the long circular arc part 14e can be improved.
[0056]
【The invention's effect】
  As detailed above, claims 1 to9The described invention can ensure the predetermined rigidity of the ring core and can reduce its weight.
[0057]
  Claim1Or2The described invention can ensure the predetermined rigidity of the short arc portion of the ring core and can reduce the weight thereof.
  Claim3In the described invention, the small-diameter portion can be easily formed by forming the flat concave portion in the outer edge portion of the outer wall portion and the inner wall portion.
[0058]
  Claim4In the described invention, the formation angle of the flat concave portion provided on the outer wall portion is set to be larger than the formation angle of the flat concave portion formed on the inner wall portion. Can be done well.
[0059]
  Claim5In the described invention, in the steering reference state, the cross-sectional area of the middle arc portion and both short arc portions on the driver's seat side or the cross-sectional area of both short arc portions is set smaller than the cross-sectional area of the long arc portion on the side opposite to the driver seat. Therefore, the balance of rigidity can be appropriately maintained, and the weight of the ring core can be reduced efficiently.
[0060]
  Claim6In the described invention, since the reinforcing rib is provided in the groove portion of the small diameter portion, the predetermined rigidity can be ensured and the weight can be reduced.
  Claim7In the described invention, since the reinforcing rib also serves as a receiving seat for the knock pin of the molding apparatus, the product after molding can be easily taken out.
[0061]
  Claim8In the described invention, since the reinforcing block portion is provided in the groove portion at the base end portion of the long arc portion, the torsional rigidity at the left and right base end portions of the long arc portion can be improved.
[0062]
  Claim9In the described invention, a reinforcing rib is formed on the first and second spoke cores extending in the left-right direction, and a box-shaped rib is formed between the reinforcing rib and the inner wall of the ring core. Therefore, when the torsional rigidity of the connecting portion between the first and second spoke cores and the ring core is improved and the rigidity is kept constant, the spoke core can be reduced in weight. .
[Brief description of the drawings]
FIG. 1 is a perspective view showing a state in which a metal core of a steering wheel of the present invention is viewed from the back side.
FIG. 2 is an enlarged perspective view showing a main part of a cored bar.
FIG. 3 is a longitudinal sectional view of a steering wheel.
FIG. 4 is a back view of the cored bar.
5 is an enlarged cross-sectional view of the ring cored bar taken along line 1-1 of FIG.
6 is an enlarged cross-sectional view of the ring cored bar taken along line 2-2 in FIG. 4;
7 is an enlarged cross-sectional view of a ring cored bar taken along line 3-3 in FIG.
8 is an enlarged cross-sectional view of the ring cored bar taken along line 4-4 of FIG.
FIG. 9 is an enlarged cross-sectional view of a ring cored bar taken along line 5-5 in FIG. 4;
10 is an enlarged cross-sectional view of the ring cored bar taken along line 6-6 in FIG. 4;
11 is an enlarged cross-sectional view of the ring cored bar taken along line 7-7 in FIG. 4;
FIG. 12 is a partial cross-sectional view illustrating a method for forming a ring cored bar.
FIG. 13 is a back view showing another example of the cored bar.
FIG. 14 is a perspective view of a metal core of a conventional steering wheel.
[Explanation of symbols]
α1, α2, β1 to β4 ... Forming angle, 12 ... Core, 14 ... Ring core, 14a ... Bottom wall, 14b ... Outside wall, 14c ... Inside wall, 14d ... Groove, 14e ... Long arc part , 14f ... medium arc part, 14g ... short arc part, 14l ... reinforcing rib, 14m ... receiving seat, 14n ... reinforcing block part, 14q ... flat concave part, 14h-14k ... first to fourth small diameter parts, 17 ~ DESCRIPTION OF SYMBOLS 20 ... 1st-4th spoke part core, 19A ... 3rd spoke part core, 21a ... Boss part, 22 ... Steering shaft, 31-34 ... 1st-4th connection part, 43 ... Knock pin.

Claims

A ring cored bar (14) having a groove (14d) having a U-shaped cross section;
A boss portion (21a) which is located at the center of the ring core metal (14) and is attached to the steering shaft (22);
First and second spoke cores (17, 18) connected between the boss (21a) and the ring core (14) and extending in the left-right direction in the steering reference state;
Similarly, the third and fourth spoke metal cores (19, 19) connected between the boss part (21a) and the ring metal core (14) and extending in an inclined state from the driver seat side toward the center in the steering reference state. 20) and
In the steering wheel mandrel (12) with
The length opposite to the driver's seat defined by the first to fourth connecting portions (31 to 34) of the ring portion core (14) and the first to fourth spoke cores (17 to 20). Of the arc portion (14e), the middle arc portion (14f) on the driver's seat side, and the pair of left and right short arc portions (14g, 14g) near the driver seat, at least the pair of left and right short arc portions (14g, 14g) have a small diameter. Steering wheel core bar provided with each portion (14i, 14j).

A ring cored bar (14) having a groove (14d) having a U-shaped cross section;
A boss portion (21a) which is located at the center of the ring core metal (14) and is attached to the steering shaft (22);
First and second spoke cores (17, 18) connected between the boss (21a) and the ring core (14) and extending in the left-right direction in the steering reference state;
Similarly, a third spoke core (19A) connected between the boss (21a) and the ring core (14) and extending in the center direction from the driver seat side in the steering reference state.
In the steering wheel mandrel (12) with
Opposite to the driver's seat defined by the ring part core (14) and the first to third connecting parts (31, 32, 33) of the first to third spoke part cores (17, 18, 19A). Of the left long arc portion (14e) and the pair of left and right short arc portions (14g, 14g) on the driver's seat side, at least the pair of left and right short arc portions (14g, 14g) are provided with small diameter portions (14i, 14j), respectively. Steering wheel core bar provided.

In Claim 1 or 2, the said small diameter part (14i, 14j) is formed of the flat concave part (14q) formed in the outer-periphery edge part of the said outer side wall part (14b) and an inner wall part (14c), respectively. Steering wheel core metal.

In claim 3, the four arc portions or the three arc portions are formed with first to fourth small diameter portions (14h to 14k) or first to third small diameter portions (14h, 14i, 14j), The formation angle (α1) of the flat concave portion (14q) formed on the outer wall portion (14b) of the long arc portion (14e) with respect to the center (O) of the ring core metal 14 is the inner wall portion (14c). Is set larger than the forming angle (β1) of the flat concave portion (14q) formed on the outer side of the middle arc portion (14f) and both short arc portions (14g, 14g) or both short arc portions (14g, 14g). The formation angle (α2) related to the center (O) of the flat concave portion (14q) formed in the wall portion (14b) is the formation angle of the flat concave portion (14q) formed in the inner wall portion (14c). Larger than (β2 to β4, β2, β3), and the middle arc portion 14f) and both short arc portions (14 g, almost the entire or the core metal of the steering wheel which is set over substantially the entire region of both short arc portions (14g, 14g) of 14 g).

The cross sectional area of the middle arc portion (14f) and both short arc portions (14g, 14g) or the cross sectional area of both short arc portions (14g, 14g) is the cross sectional area of the long arc portion (14e). Steering wheel core metal that is set smaller than.

3. The steering wheel core bar according to claim 1, wherein a reinforcing rib (141) is provided in the groove (14d) of the small diameter portion (14i, 14j).

The steering wheel core bar according to claim 6, wherein the reinforcing rib (14l) also serves as a receiving seat (14m) of a knock pin (43) of a molding apparatus.

The groove part of both the base end parts of the said long circular arc part (14e) in Claim 1 or 2 (14d) is a steering wheel core bar provided with reinforcing block portions (14n, 14n).

3. The first and second spoke cores (17, 18) extending in the left-right direction according to claim 1 or 2, wherein the first and second spoke cores (17, 18) are a bottom wall (17a, 18a) and left and right side walls (17b, 17c, 18b, 18c). ), The cross section is formed into a flat U-shape, and both spokes near the first and second connecting portions (31, 32) between the spoke core metal (17, 18) and the ring core metal (14). Reinforcing ribs (17e, 18e) are formed on both side wall portions (17b, 17c, 18b, 18c) of the cored bar (17, 18). The reinforcing ribs (17e, 18e) and the ring cored bar (14 ) Of the steering wheel in which box-like ribs (17f, 18f) are formed between the inner wall portion (14c).