JP2004176605A

JP2004176605A - Rocker arm

Info

Publication number: JP2004176605A
Application number: JP2002342613A
Authority: JP
Inventors: Noriyuki Takeo; 則之竹尾
Original assignee: NSK Ltd
Current assignee: NSK Ltd
Priority date: 2002-11-26
Filing date: 2002-11-26
Publication date: 2004-06-24

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure easily enabling an operation for bending part of a second connecting portion 4a constituting a rocker arm 1a, to ensure the rigidity of the second connecting portion 4a, and to reduce weight of the rocker arm 1a. <P>SOLUTION: Both edge portions that are part of the second connecting portion 4a and at least includes a second engaging portion 7 have no pair of side wall portions 2a, 2a. A reinforcing portion 16 is provided by welding and fixing tip edges of arms 15, 15 extending from one edge of the both side wall portions 2a, 2a into part of a spherical convex part 18. Between the reinforcing portion 16 and the both side edges of the second connecting portion 4a, a clearance 19 is interposed. This structure makes it possible to solve the above problems. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
この発明は、エンジンの動弁機構に組み込み、カムシャフトの回転を弁体（吸気弁及び排気弁）の往復運動に変換する為のロッカーアームの改良に関する。
【０００２】
【従来の技術】
レシプロエンジン（往復ピストンエンジン）には、一部の２サイクルエンジンを除き、クランクシャフトの回転と同期して開閉する吸気弁及び排気弁を設けている。この様なレシプロエンジンでは、上記クランクシャフトの回転と同期して（４サイクルエンジンの場合には１／２の回転速度で）回転するカムシャフトの動きを、ロッカーアームにより、上記吸気弁及び排気弁に伝達し、これら吸気弁及び排気弁をそれぞれの軸方向に往復運動させる。
【０００３】
この様なエンジンの動弁機構に組み込むロッカーアームとして従来一般的には、鋳造品（鋳鉄品或はアルミニウムダイキャスト品）を使用していた。これに対して近年、鋼板等の金属板にプレス加工を施す事により上記ロッカーアームを造る事が考えられ、一部で実施されている。この様な金属板製のロッカーアームを使用する理由は、鋳造品は重量が嵩んだり（鋳鉄品の場合）、或は十分に強度を確保する為には容積が嵩張る（アルミニウムダイキャスト品の場合）他、一般的にはロストワックス法により造る為、製造コストが嵩む為である。
【０００４】
この様な事情で考えられた板金製のロッカーアームに関する従来技術として、特許文献１に記載されたものがある。図５〜１１は、この特許文献１に記載された、ロッカーアームとその製造方法とに関する発明を表している。尚、このロッカーアームとその製造方法に就いては、上記特許文献１等に詳しく記載されており、従来から知られている為、ここでは簡単に説明する。この従来のロッカーアーム１は、図５に示す様に、互いにほぼ平行な１対の側壁部２、２と、これら両側壁部２、２の幅方向一端縁同士を連結する第一の連結部３及び第二の連結部４とを有する。又、これら両側壁部２、２の長さ方向中間部に１対の円孔５、５を、互いに同心に形成し、これら両円孔５、５に、カムと係合するローラを回転自在に支持する為の支持軸の両端部を支持自在としている。上記第一の連結部３及び第二の連結部４のうち、第一の連結部３は、弁体の基端部を突き当てる為の第一の係合部６を、第二の連結部４は、ラッシュアジャスタ等の揺動支持部材の先端部を突き当てる為の第二の係合部７を、それぞれ有している。尚、図示は省略するが、第二の連結部にねじ孔を形成し、このねじ孔部分にアジャストねじを螺着する構造も、特許文献２等に記載されて、従来から広く知られている。
【０００５】
上述の様なロッカーアーム１を造る場合、先ず第一工程で、図６に示す様な形状を有する第一素板８を造る。続く第二工程で、この第一素板８の中央部に、図７（Ａ）に示す様に透孔９を形成して、第二素板１０とする。この第二素板１０には、続く第三工程で、曲げ加工等を施して、図８に示す様な第一中間素材１１とする。この第一中間素材１１は、幅方向に関して左右１対の側壁部２、２と、これら両側壁部２、２の幅方向｛図８（Ｃ）（Ｄ）の左右方向｝端縁同士を連結する湾曲部１２とから成る。そして、続く第四工程でこの湾曲部１２に押圧加工を施し、図９に示す様な第二中間素材１３とする。即ち、上記第四工程では、上記湾曲部１２を平板状に加工すると共に厚さを増大させて、第一の連結部３及び第二の連結部４とする。更に、次の第五工程でこれら第一の連結部３及び第二の連結部４に塑性加工若しくは切削加工、更には必要とする研削加工を施し、図１０に示す様に、上記第一の連結部３に第一の係合部６を、上記第二の連結部４に第二の係合部７を、それぞれ形成して、第三中間素材１４とする。
【０００６】
この様にして得られた第三中間素材１４には、次の第六工程で、１対の側壁部２、２の中間部で互いに整合する位置に、それぞれ円孔５、５を、プレス加工、或は旋削加工により形成して、図５、１１に示す様なロッカーアーム１として完成する。この様なロッカーアーム及びその製造方法は、ロッカーアームの強度や剛性の向上を図れるだけでなく、工数及び部品点数の削減により、コストの低減、精度の向上、設備の簡略化を図れる為、高品質のロッカーアームを低コストで実現できる。
【０００７】
【特許文献１】
特開２０００−１２０４１１号公報
【特許文献２】
特開２００１−５９４０７号公報
【０００８】
【発明が解決しようとする課題】
ところで、上述したロッカーアーム１の第一の連結部３と第二の連結部４とは、互いにほぼ平行（同一平面上）に形成されているが、これら第一の連結部３と第二の連結部４とを互いに平行でない状態に形成する（同一平面上に位置させない）場合がある。即ち、エンジンの設計上の理由により、この第一の連結部３に備えた上記第一の係合部６と係合する吸気弁或は排気弁である弁体と、上記第二の連結部４に備えた上記第二の係合部７と係合するラッシュアジャスタ等の揺動支持部材とが、互いに平行でない状態で設置される場合がある。特に、上記弁体と揺動支持部材との成す角度が大きい場合、上記弁体に対して上記第一の係合部６を、上記揺動支持部材に対して上記第二の係合部７を、それぞれ確実に係合させる為には、上記第一の連結部３と第二の連結部４との、少なくとも上記第一の係合部６と第二の係合部７とがそれぞれ存在する部分を、互いに平行でない状態とする必要がある。
【０００９】
この為に、上記第一、第二の連結部３、４のうちの一方の連結部の一部で上記第一の係合部６若しくは第二の係合部７が存在する部分を、この連結部の厚さ方向｛図１１（Ｂ）の上下方向｝に折り曲げる事が考えられる。しかし、上述したロッカーアーム１の場合、上記第一の連結部３若しくは第二の連結部４の一部を厚さ方向に折り曲げるには、これら第一の連結部３若しくは第二の連結部４の一部だけでなく、これら第一の連結部３若しくは第二の連結部４の両側縁部に存在する両側壁部２、２の端部｛図１１（Ａ）、（Ｂ）の右端部若しくは左端部｝も、同時に折り曲げる必要がある。この様に、これら両側壁部２、２の端部を上記第一、第二の連結部３、４の厚さ方向に折り曲げる作業は、難しく手間がかかる他、これら両側壁部２、２の端部を折り曲げる作業の際に、これら両側壁部２、２の一部に亀裂等の損傷が発生する場合がある。
本発明のロッカーアームは、この様な事情に鑑みて、連結部の一部を折り曲げる作業を、容易に行なえる構造を実現すべく発明したものである。
【００１０】
【課題を解決するための手段】
本発明のロッカーアームは、従来構造と同様に、金属板に塑性加工を施す事により造られ、１対の側壁部と、連結部とを備える。
このうちの両側壁部は、互いに間隔をあけて設けられている。
又、上記連結部は、上記両側壁部の幅方向一端縁同士を連結するものであり、弁体若しくは揺動支持部材と係合する係合部を有している。
又、上記連結部の一部で、少なくとも上記係合部が存在する部分の両側縁部には、上記両側壁部が存在しない。
又、上記両側壁部の長さ方向片端部から延出した腕部の先端縁を上記連結部の一部に突き当て固定する事により、この連結部の剛性を確保する為の補強部とすると共に、これら連結部の幅方向両側縁と補強部との間に隙間を介在させている。
【００１１】
【作用】
上述の様に構成される本発明のロッカーアームの場合には、連結部の一部で、少なくとも係合部が存在する部分の両側縁部には両側壁部が存在しない為、この連結部の一部を厚さ方向に折り曲げる作業が容易である。又、この連結部の剛性を確保すると共に、ロッカーアームの軽量化を図る事ができる。
【００１２】
【発明の実施の形態】
図１〜２は、本発明の実施の形態の１例を示している。尚、本例の特徴は、第二の連結部４ａの一部を折り曲げる作業を容易に行なう為に、この第二の連結部４ａの一部の両側縁部に１対の側壁部２ａ、２ａが存在しない構造とすると共に、この第二の連結部４ａの剛性を確保する点にある。ロッカーアーム１ａのその他の部分の構成は、前述の図５、１１に示した従来構造の場合と同様であるから、同等部分には同一符号を付して、重複する説明は省略若しくは簡略にし、以下、本発明の特徴部分を中心に説明する。
【００１３】
本例のロッカーアーム１ａは、揺動支持部材であるラッシュアジャスタと係合する第二の係合部７が存在する、上記第二の連結部４ａの中間部乃至先端部の両側縁部には、上記両側壁部２ａ、２ａが存在しない。従って、これら両側壁部２ａ、２ａの第二の連結部４ａ側の幅方向（図１の上下方向）一端縁部（図１の下端縁部）は、この第二の連結部４ａの基端部（図１、２の右端部）のみで連結されている。
【００１４】
又、本の場合には、上記第二の係合部７が存在する、上記第二の連結部４ａの中間部乃至先端部を、この第二の連結部４ａの厚さ方向片側（図１の下側）に折り曲げている。即ち、本例のロッカーアーム１ａは、例えば、エンジンの設計上の理由により、第一の係合部６と係合する弁体と、上記ラッシュアジャスタとが互いに平行でない状態で設けられた構造で、特にこれら弁体とラッシュアジャスタとの成す角度が大きい構造に使用される。従って、上記第二の係合部７が存在する、上記第二の連結部４ａの中間部乃至先端部を折り曲げる事により、この第二の係合部７が存在する部分と、第一の連結部３の一部で上記第一の係合部６が存在する部分とが互いに平行でない（同一平面上に位置しない）状態としている。尚、本例の場合には、上記第二の係合部７に揺動支持部材としてラッシュアジャスタを係合する例を示しているが、第二の連結部にねじ孔を形成し、このねじ孔部分にアジャストねじを螺着する構造に関しても、本発明を適用できる。
【００１５】
又、上記両側壁部２ａ、２ａの長さ方向（図１、２の左右方向）片端部（左端部）で幅方向他端縁（図１の上端縁）側から延出した腕部１５、１５の先端縁を上記第二の連結部４ａの一部に突き当て固定する事により、この第二の連結部４ａの剛性を確保する為の補強部１６としている。尚、本例の場合、上記ラッシュアジャスタの先端部を揺動変位自在に突き当てる為に上記第二の連結部４ａの片面（図１の下面）に、第二の係合部である球状凹部１７を形成している。又、この球状凹部１７の形成に伴い、この第二の連結部４ａの他面（図１の上面）には球状凸部１８を形成してる。更に、上記両側壁部２ａ、２ａの長さ方向片端部を上記第二の係合部７に対し、この第二の係合部７の他面側に折り曲げ形成している。そして、上記両側壁部２ａ、２ａの長さ方向片端部から延出した上記腕部１５、１５の先端縁を、上記第二の連結部４ａの一部である、上記球状凸部１８の一部に溶接固定する事により、上記補強部１６を構成している。又、本例では、上記第二の連結部４ａの幅方向（図２の上下方向）両側縁と補強部１６との間に隙間１９を介在させている。
【００１６】
上述の様に構成される本例のロッカーアーム１ａは次の様に形成される。先ず、前述した図６の様に、第一工程で第一素板８を形成する。続く第二工程で、図３に示す様に、この第一素板８の中央部に透孔９を形成する際に、上記ロッカーアーム１ａの完成状態で上記各側壁部２ａ、２ａとなる、１対の翼状部２０の長さ方向（図３の左右方向）片端部（左端部）に、それぞれ切り欠き２１を形成して、第二の裏板１０ａとする。即ち、上記各翼状部２０の長さ方向片端縁から、上記第二の連結部４ａの一部を折り曲げる起点となる鎖線αまでの部分を、これら各翼状部２０の長さ方向片端部の外側縁部を残して除去する事により、上記各切り欠き２１を形成する。この結果、上記第二素板１０ａを構成する基部２２の、ロッカーアーム１ａの第二の連結部４ａとなる部分の中間部乃至先端部と、上記各翼状部２０の長さ方向片端部とが、上記各切り欠き２１により隔てられて、連続しない状態となる。尚、図３では、前述した図７の場合と異なり、第二工程で上記各翼状部２０の長さ方向中央部に円孔５を形成している。
【００１７】
次に、上記各切り欠き２１を形成した上記第二素板１０ａに曲げ加工等を施す事により、図４に示す様な中間素材２３を形成する。この中間素材２３を形成する為に、上記各翼状部２０を曲げ起こして１対の側壁部２ａ、２ａとした時に、上記各切り欠き２１により連続しなくなった部分が、上記第二の連結部４ａの幅方向両側縁と補強部１６との間に存在する上記隙間１９となる。これに対して、上記各翼状部２０の片端部で上記各切り欠き２１を形成した残部である、これら各翼状部２０の片端部外側縁部が、前記各腕部１５、１５となる。そして、前記第二の係合部７が存在する、上記中間素材２３の第二の連結部４ａの中間部乃至先端部を、図１に示す様に、この第二の連結部４の厚さ方向片側（図１、４の下側）に折り曲げる。
【００１８】
上述の様に、第二の連結部４ａの一部を折り曲げたならば、上記各腕部１５、１５の先端部を前記球状凸部１８の一部に溶接固定して、前記補強部１６を形成する。即ち、図２に示す様に、上記各腕部１５、１５の中間部を上記球状凸部１８側に折り曲げる事により、これら各腕部１５、１５の先端部をこの球状凸部１８を挟持する様に突き当てる。そして、これら各腕部１５、１５の先端部とこの球状凸部１８との当接部を溶接する。この結果、図１、２に示す様なロッカーアーム１ａを得る事ができる。
【００１９】
上述の様に構成される本発明のロッカーアーム１ａの場合には、上記第二の連結部４ａの一部（中間部乃至先端部）で、上記第二の係合部７が存在する部分の両側縁部には上記両側壁部２ａ、２ａが存在しない為、この第二の連結部４ａの一部を厚さ方向片側に折り曲げる作業が容易である。即ち、前述の図５、１１に示した従来構造のロッカーアーム１の場合、第二の連結部４の一部で第二の係合部７が存在する部分の両側縁部に両側壁部２、２が存在する為、この第二の連結部４の一部を厚さ方向に折り曲げる際にこれら両側壁部２、２も折り曲げる必要がある。これに対して本例の場合、上記第二の連結部４ａの一部で第二の係合部７が存在する部分の両側縁部に両側壁部２ａ、２ａが存在しない為、この第二の連結部４ａの一部を厚さ方向に折り曲げる際にこれら両側壁部２ａ、２ａを折り曲げる必要がない。従って、上記第二の連結部４ａの一部を折り曲げる作業が容易である。
【００２０】
又、本例の様に、第二の連結部４ａの中間部乃至先端部の両側縁部に上記両側壁部２ａ、２ａが存在しない構造とした場合、この第二の連結部４ａの剛性が低くなる。従って、このままでは、使用時に前記ラッシュアジャスタとの係合により上記第二の係合部７に作用する応力により上記第二の連結部４ａが変形する。この為、本例では、上記補強部１６を設けてこの第二の連結部４ａの剛性を確保している。
【００２１】
更に、本例の場合、上記第二の連結部４ａの幅方向両側縁と上記補強部１６との間に上記隙間１９を介在させている為、上記ロッカーアーム１ａの軽量化を図る事ができる。この様にロッカーアーム１ａの軽量化を図る事は、このロッカーアーム１ａを高速で揺動させる為には好ましい。即ち、ロッカーアーム１ａをエンジンに組み込んで使用する場合、このロッカーアーム１ａを揺動させて吸気弁或は排気弁である弁体の開閉を行なう。このロッカーアーム１ａはクランクシャフトの回転と同期して回転するカムシャフトにより揺動する。従って、このロッカーアーム１ａはエンジンの回転数の上昇に伴い高速で揺動する。この為、このロッカーアーム１ａを軽量化して慣性質量を小くすれば、このロッカーアーム１ａを高速で揺動させ易くなる。
【００２２】
尚、本例では、上記第二の連結部４ａ側の両側壁部２ａ、２ａが存在しない場合に就いて説明したが、本発明は、吸気弁或は排気弁である弁体と係合する第一の係合部６を有する第一の連結部３側の両側壁部２ａ、２ａが存在しない構造としても良い。この様な構造は、上述した本例の構造と比べて、ロッカーアームを高速で揺動させ易くなる。即ち、ロッカーアームの使用時は、第二の連結部に形成した第二の係合部とラッシュアジャスタ等の揺動支持部材との係合部分を揺動中心として、上記ロッカーアームが揺動する。従って、この揺動中心から離れた上記第一の連結部３側が軽量化されれば、上記ロッカーアームをより高速で揺動させ易くなる。
【００２３】
【発明の効果】
本発明は、以上に述べた通り構成され作用するので、ロッカーアームの連結部の一部を折り曲げる作業を容易にできると共に、この連結部の剛性を確保できる構造を実現できる。又、ロッカーアームの軽量化にも寄与できる。
【図面の簡単な説明】
【図１】本発明の実施の形態の１例を示す、図２のＡ−Ａ断面図。
【図２】同じく平面図。
【図３】本発明のロッカーアームを得る為の第二素板を示す部分平面図。
【図４】同じく中間素材を示す、図１と同様の図。
【図５】従来から知られているロッカーアームの斜視図。
【図６】従来から知られているロッカーアームの製造方法の第一工程により得られる第一素板を示しており、（Ａ）は平面図、（Ｂ）は（Ａ）のａ−ａ断面図、（Ｃ）は（Ａ）のｂ−ｂ断面図、（Ｄ）は（Ａ）のｃ−ｃ断面図。
【図７】同第二工程により得られる第二素板を示しており、（Ａ）は平面図、（Ｂ）は（Ａ）のａ−ａ断面図、（Ｃ）は（Ａ）のｂ−ｂ断面図、（Ｄ）は（Ａ）のｃ−ｃ断面図。
【図８】同第三工程により得られる第一中間素材を示しており、（Ａ）は平面図、（Ｂ）は（Ａ）のａ−ａ断面図、（Ｃ）は（Ａ）のｂ−ｂ断面図、（Ｄ）は（Ａ）のｃ−ｃ断面図。
【図９】同第四工程により得られる第二中間素材を示しており、（Ａ）は平面図、（Ｂ）は（Ａ）のａ−ａ断面図、（Ｃ）は（Ａ）のｂ−ｂ断面図、（Ｄ）は（Ａ）のｃ−ｃ断面図。
【図１０】同第五工程により造られる第三中間素材を示しており、（Ａ）は平面図、（Ｂ）は（Ａ）のａ−ａ断面図、（Ｃ）は（Ａ）のｂ−ｂ断面図、（Ｄ）は（Ａ）のｃ−ｃ断面図。
【図１１】同第六工程を経て完成したロッカーアームを示しており、（Ａ）は平面図、（Ｂ）は（Ａ）のａ−ａ断面図、（Ｃ）は（Ａ）のｂ−ｂ断面図、（Ｄ）は（Ａ）のｃ−ｃ断面図。
【符号の説明】
１、１ａロッカーアーム
２、２ａ側壁部
３第一の連結部
４、４ａ第二の連結部
５円孔
６第一の係合部
７第二の係合部
８第一素板
９透孔
１０、１０ａ第二素板
１１第一中間素材
１２湾曲部
１３第二中間素材
１４第三中間素材
１５腕部
１６補強部
１７球状凹部
１８球状凸部
１９隙間
２０翼状部
２１切り欠き
２２基部
２３中間素材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in a rocker arm that is incorporated in a valve mechanism of an engine and converts rotation of a camshaft into reciprocating motion of a valve body (an intake valve and an exhaust valve).
[0002]
[Prior art]
The reciprocating engine (reciprocating piston engine) is provided with an intake valve and an exhaust valve that open and close in synchronization with the rotation of the crankshaft, except for some two-stroke engines. In such a reciprocating engine, the movement of the camshaft rotating in synchronization with the rotation of the crankshaft (at a rotation speed of １／ in the case of a four-cycle engine) is controlled by the rocker arm using the intake valve and the exhaust valve. To reciprocate the intake and exhaust valves in their respective axial directions.
[0003]
Conventionally, a cast product (a cast iron product or an aluminum die-cast product) has been generally used as a rocker arm to be incorporated in such a valve operating mechanism of an engine. On the other hand, in recent years, it has been considered that the rocker arm is manufactured by pressing a metal plate such as a steel plate or the like, and this is partially implemented. The reason for using such a rocker arm made of a metal plate is that the cast product is heavy (in the case of a cast iron product), or the volume is bulky in order to secure sufficient strength (for the aluminum die-cast product). Case) In addition, since it is generally manufactured by the lost wax method, the production cost increases.
[0004]
As a prior art relating to a sheet metal rocker arm considered under such circumstances, there is one described in Patent Document 1. 5 to 11 show an invention related to a rocker arm and a method for manufacturing the same described in Patent Document 1. FIG. The rocker arm and the method of manufacturing the rocker arm are described in detail in Patent Literature 1 and the like, and have been known in the related art. As shown in FIG. 5, the conventional rocker arm 1 has a pair of side walls 2 and 2 which are substantially parallel to each other, and a first connecting portion which connects one edge in the width direction of the side walls 2 and 2 to each other. 3 and a second connecting portion 4. Further, a pair of circular holes 5, 5 are formed concentrically with each other in the longitudinally intermediate portions of the side walls 2, 2, and rollers engaging with a cam are rotatable in the circular holes 5, 5. The both ends of the support shaft for supporting the support shaft can be freely supported. The first connecting portion 3 of the first connecting portion 3 and the second connecting portion 4 includes a first engaging portion 6 for abutting a base end portion of the valve body, and a second connecting portion. Reference numerals 4 each include a second engaging portion 7 for abutting the tip of a swing support member such as a lash adjuster. Although not shown, a structure in which a screw hole is formed in the second connecting portion and an adjusting screw is screwed into this screw hole portion is also described in Patent Document 2 and the like, and has been widely known. .
[0005]
When manufacturing the rocker arm 1 as described above, first, in a first step, a first raw plate 8 having a shape as shown in FIG. 6 is manufactured. In a subsequent second step, a through hole 9 is formed in the center of the first base plate 8 as shown in FIG. In the subsequent third step, the second base plate 10 is subjected to bending or the like to form a first intermediate material 11 as shown in FIG. The first intermediate material 11 connects a pair of left and right side walls 2 and 2 with respect to the width direction and ends of the side walls 2 and 2 in the width direction {right and left direction in FIGS. 8C and 8D}. And a curved portion 12. Then, in a subsequent fourth step, the curved portion 12 is subjected to a pressing process to obtain a second intermediate material 13 as shown in FIG. That is, in the fourth step, the curved portion 12 is processed into a flat plate shape and the thickness thereof is increased to form the first connecting portion 3 and the second connecting portion 4. Further, in the next fifth step, the first connecting portion 3 and the second connecting portion 4 are subjected to plastic working or cutting, and further necessary grinding, and as shown in FIG. The first engaging part 6 is formed on the connecting part 3 and the second engaging part 7 is formed on the second connecting part 4, respectively, to form the third intermediate material 14.
[0006]
In the third intermediate material 14 thus obtained, in the next sixth step, circular holes 5, 5 are respectively formed by pressing at positions where they are aligned with each other at the intermediate portion between the pair of side wall portions 2, 2. Alternatively, it is formed by turning to complete a rocker arm 1 as shown in FIGS. Such a rocker arm and its manufacturing method can not only improve the strength and rigidity of the rocker arm but also reduce costs, improve accuracy, and simplify equipment by reducing man-hours and the number of parts. A quality rocker arm can be realized at low cost.
[0007]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-120411 [Patent Document 2]
JP 2001-59407 A
[Problems to be solved by the invention]
By the way, the first connecting portion 3 and the second connecting portion 4 of the rocker arm 1 described above are formed substantially in parallel with each other (on the same plane). There is a case where the connecting portion 4 and the connecting portion 4 are formed so as not to be parallel to each other (not positioned on the same plane). That is, due to the design of the engine, a valve body that is an intake valve or an exhaust valve that engages with the first engagement portion 6 provided in the first connection portion 3 and the second connection portion In some cases, the swing support member such as a lash adjuster that engages with the second engagement portion 7 provided in the fourth member 4 is not parallel to each other. In particular, when the angle between the valve body and the swing support member is large, the first engagement portion 6 is attached to the valve body, and the second engagement portion 7 is attached to the swing support member. In order to ensure that the first and second connecting portions are engaged, at least the first and second engaging portions 6 and 7 of the first and second connecting portions 3 and 4 respectively exist. Parts that do not have to be parallel to each other.
[0009]
For this reason, the part where the first engagement part 6 or the second engagement part 7 is present in a part of one of the first and second connection parts 3 and 4 is It is conceivable that the connecting portion is bent in the thickness direction {vertical direction in FIG. 11B}. However, in the case of the rocker arm 1 described above, in order to bend a part of the first connecting portion 3 or the second connecting portion 4 in the thickness direction, the first connecting portion 3 or the second connecting portion 4 is required. Of the first connecting portion 3 or the second connecting portion 4, the ends of the side walls 2, 2 which are present on both side edges of the first connecting portion 3 or the second connecting portion 4 {right end portions in FIGS. Alternatively, it is necessary to bend the left end｝ at the same time. As described above, the work of bending the end portions of the side wall portions 2 and 2 in the thickness direction of the first and second connection portions 3 and 4 is difficult and time-consuming, and the operation of bending the side wall portions 2 and 2 is difficult. During the work of bending the ends, damages such as cracks may occur in a part of these side walls 2, 2.
In view of such circumstances, the rocker arm of the present invention has been invented in order to realize a structure that can easily perform a work of bending a part of the connecting portion.
[0010]
[Means for Solving the Problems]
The rocker arm according to the present invention is formed by subjecting a metal plate to plastic working, similarly to the conventional structure, and includes a pair of side walls and a connecting portion.
Of these, both side walls are provided with an interval therebetween.
The connecting portion connects one edge in the width direction of the both side wall portions, and has an engaging portion that engages with the valve body or the swing support member.
In addition, the side wall portions do not exist at least on both side edges of a portion of the connection portion where the engagement portion exists.
Further, the distal end edges of the arms extending from one longitudinal end of the both side walls are abutted and fixed to a part of the connecting portion, thereby forming a reinforcing portion for securing the rigidity of the connecting portion. At the same time, a gap is provided between both side edges of these connecting portions in the width direction and the reinforcing portion.
[0011]
[Action]
In the case of the rocker arm of the present invention configured as described above, since both side walls do not exist at least on both side edges of the portion where the engagement portion exists, a part of the connection portion. The work of bending a part in the thickness direction is easy. Further, the rigidity of the connecting portion can be ensured, and the weight of the rocker arm can be reduced.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 show an example of an embodiment of the present invention. The feature of this example is that a pair of side wall portions 2a, 2a are provided on both side edges of a part of the second connecting portion 4a so as to easily bend the part of the second connecting portion 4a. And the second connecting portion 4a is secured. The other parts of the configuration of the rocker arm 1a are the same as those of the conventional structure shown in FIGS. 5 and 11 described above. Therefore, the same reference numerals are given to the same parts, and the overlapping description is omitted or simplified. Hereinafter, the description will focus on the features of the present invention.
[0013]
The rocker arm 1a of this example has a second engaging portion 7 that engages with a lash adjuster that is a swing support member. , The two side walls 2a, 2a do not exist. Therefore, one end edge (lower edge in FIG. 1) of the width direction (vertical direction in FIG. 1) of the two side walls 2a, 2a on the side of the second connecting portion 4a is the base end of the second connecting portion 4a. It is connected only at the portion (right end in FIGS. 1 and 2).
[0014]
Further, in the case of a book, the middle to the front end of the second connecting portion 4a where the second engaging portion 7 exists is connected to one side in the thickness direction of the second connecting portion 4a (FIG. 1). Beneath). That is, the rocker arm 1a of the present embodiment has a structure in which, for example, the valve element that engages with the first engagement portion 6 and the lash adjuster are provided in a state where they are not parallel to each other for reasons of engine design. In particular, it is used for a structure in which the angle between the valve body and the lash adjuster is large. Accordingly, by bending the intermediate portion or the tip portion of the second connecting portion 4a where the second engaging portion 7 exists, the portion where the second engaging portion 7 exists and the first connecting portion 4a are connected. A portion of the portion 3 where the first engagement portion 6 exists is not parallel to each other (not located on the same plane). In the case of this example, an example is shown in which a lash adjuster as a swing support member is engaged with the second engaging portion 7. However, a screw hole is formed in the second connecting portion, and the screw hole is formed. The present invention can be applied to a structure in which an adjusting screw is screwed into a hole.
[0015]
Also, an arm 15 extending from one end (left end) in the length direction (left / right direction in FIGS. 1 and 2) of the both side walls 2a, 2a from the other end in the width direction (upper end in FIG. 1). The reinforcing portion 16 for securing the rigidity of the second connecting portion 4a is obtained by abutting and fixing the leading edge of the second connecting portion 15 to a part of the second connecting portion 4a. In the case of this example, a spherical concave portion as a second engaging portion is provided on one surface (the lower surface in FIG. 1) of the second connecting portion 4a so as to abut the tip of the lash adjuster so as to be swingably displaceable. 17 are formed. Along with the formation of the spherical concave portion 17, a spherical convex portion 18 is formed on the other surface (the upper surface in FIG. 1) of the second connecting portion 4a. Further, one end in the length direction of the both side walls 2a, 2a is bent toward the other surface of the second engaging portion 7 with respect to the second engaging portion 7. The distal ends of the arms 15, 15 extending from one end in the length direction of the side walls 2a, 2a are connected to the spherical projections 18, which are a part of the second connecting portion 4a. The reinforcing portion 16 is formed by welding and fixing to the portion. In this example, a gap 19 is interposed between the reinforcing portion 16 and both side edges of the second connecting portion 4a in the width direction (vertical direction in FIG. 2).
[0016]
The rocker arm 1a of the present example configured as described above is formed as follows. First, as shown in FIG. 6, the first base plate 8 is formed in the first step. In the subsequent second step, as shown in FIG. 3, when the through hole 9 is formed in the central portion of the first raw plate 8, the rocker arm 1a becomes the completed side walls 2a and 2a when the rocker arm 1a is completed. A notch 21 is formed at one end (left end) of the pair of wings 20 in the length direction (the left-right direction in FIG. 3) to form a second back plate 10a. That is, a portion from one longitudinal edge of each of the wings 20 to a chain line α serving as a starting point for bending a part of the second connecting portion 4a is located outside of one longitudinal end of each of the wings 20. The above-mentioned notches 21 are formed by removing the edge portions. As a result, the middle portion or the tip portion of the base portion 22 constituting the second base plate 10a to be the second connecting portion 4a of the rocker arm 1a and one end in the length direction of each wing portion 20 are formed. , Are not continuous with each other separated by the notches 21. In FIG. 3, unlike the case of FIG. 7 described above, the circular hole 5 is formed at the center in the length direction of each wing 20 in the second step.
[0017]
Next, an intermediate material 23 as shown in FIG. 4 is formed by performing a bending process or the like on the second base plate 10a having the cutouts 21 formed thereon. In order to form the intermediate material 23, when each of the wings 20 is bent and raised to form a pair of side walls 2a, 2a, a portion that is discontinued due to each of the cutouts 21 is formed by the second connecting portion. The gap 19 is present between the reinforcing member 16 and both side edges in the width direction of 4a. On the other hand, the outer edge of one end portion of each wing portion 20, which is the remaining portion where the notch 21 is formed at one end portion of each wing portion 20, becomes the arm portion 15, 15. Then, as shown in FIG. 1, the thickness of the second connecting part 4 is changed from the middle part to the tip part of the second connecting part 4a of the intermediate material 23 where the second engaging part 7 exists. Fold it in one direction (the lower side in FIGS. 1 and 4).
[0018]
As described above, when a part of the second connecting portion 4a is bent, the distal ends of the arms 15 and 15 are fixed by welding to a part of the spherical convex portion 18, and the reinforcing portion 16 is fixed. Form. That is, as shown in FIG. 2, by bending the intermediate portion of each of the arms 15, 15 toward the spherical convex portion 18, the distal ends of the arms 15, 15 sandwich the spherical convex portion 18. Hit it. Then, the contact portions between the distal end portions of the arms 15 and the spherical convex portions 18 are welded. As a result, a rocker arm 1a as shown in FIGS. 1 and 2 can be obtained.
[0019]
In the case of the rocker arm 1a of the present invention configured as described above, a part (intermediate to distal end) of the second connecting portion 4a corresponds to a portion where the second engaging portion 7 exists. Since the side walls 2a, 2a do not exist on both side edges, it is easy to bend a part of the second connecting portion 4a to one side in the thickness direction. That is, in the case of the rocker arm 1 having the conventional structure shown in FIGS. 5 and 11 described above, the side wall portions 2 are formed on both side edges of a part of the second connecting portion 4 where the second engaging portion 7 exists. Since both the second connecting portion 4 and the second connecting portion 4 are bent in the thickness direction, it is necessary to also bend these side walls 2 and 2. On the other hand, in the case of the present example, since the side walls 2a and 2a do not exist on both side edges of the portion where the second engaging portion 7 is present in a part of the second connecting portion 4a, It is not necessary to bend these side walls 2a, 2a when bending a part of the connecting portion 4a in the thickness direction. Therefore, the operation of bending a part of the second connecting portion 4a is easy.
[0020]
Further, as in this example, when the structure is such that the side walls 2a and 2a do not exist on the both side edges of the intermediate portion or the distal end portion of the second connection portion 4a, the rigidity of the second connection portion 4a is reduced. Lower. Therefore, in this state, the second connecting portion 4a is deformed by the stress acting on the second engaging portion 7 due to the engagement with the lash adjuster during use. For this reason, in the present example, the rigidity of the second connecting portion 4a is secured by providing the reinforcing portion 16.
[0021]
Further, in the case of the present example, since the gap 19 is interposed between the both side edges of the second connecting portion 4a in the width direction and the reinforcing portion 16, the weight of the rocker arm 1a can be reduced. . It is preferable to reduce the weight of the rocker arm 1a in order to swing the rocker arm 1a at high speed. That is, when the rocker arm 1a is used by being incorporated into an engine, the rocker arm 1a is swung to open and close a valve body that is an intake valve or an exhaust valve. The rocker arm 1a is swung by a camshaft that rotates in synchronization with the rotation of the crankshaft. Accordingly, the rocker arm 1a swings at a high speed as the engine speed increases. Therefore, if the rocker arm 1a is reduced in weight and inertia mass is reduced, the rocker arm 1a can be easily swung at high speed.
[0022]
In this example, the case where the both side walls 2a, 2a on the side of the second connecting portion 4a are not described has been described. However, the present invention engages with a valve element which is an intake valve or an exhaust valve. It is good also as a structure which does not have the both side walls 2a and 2a by the side of the 1st connection part 3 which has the 1st engagement part 6. Such a structure makes it easier to rock the rocker arm at a higher speed than the above-described structure of the present example. That is, when the rocker arm is used, the rocker arm swings around an engagement portion between the second engagement portion formed on the second connecting portion and a swing support member such as a lash adjuster as a swing center. . Therefore, if the weight of the first connecting portion 3 away from the swing center is reduced, the rocker arm can be easily swung at a higher speed.
[0023]
【The invention's effect】
Since the present invention is configured and operates as described above, the operation of bending a part of the connecting portion of the rocker arm can be easily performed, and a structure that can secure the rigidity of the connecting portion can be realized. Also, it can contribute to the weight reduction of the rocker arm.
[Brief description of the drawings]
FIG. 1 is a sectional view taken along the line AA of FIG. 2, showing one example of an embodiment of the present invention.
FIG. 2 is a plan view of the same.
FIG. 3 is a partial plan view showing a second base plate for obtaining the rocker arm of the present invention.
FIG. 4 is a view similar to FIG. 1, showing an intermediate material.
FIG. 5 is a perspective view of a conventionally known rocker arm.
6A and 6B show a first base plate obtained by a first step of a conventionally known method of manufacturing a rocker arm, where FIG. 6A is a plan view and FIG. 6B is a sectional view taken along line aa of FIG. (C) is a bb cross-sectional view of (A), and (D) is a cc cross-sectional view of (A).
7A and 7B show a second raw plate obtained by the second step, wherein FIG. 7A is a plan view, FIG. 7B is a cross-sectional view taken along line aa of FIG. 7A, and FIG. FIG. 4B is a cross-sectional view, and FIG. 4D is a cc cross-sectional view of FIG.
8A and 8B show a first intermediate material obtained by the third step, wherein FIG. 8A is a plan view, FIG. 8B is a cross-sectional view taken along line aa of FIG. FIG. 4B is a cross-sectional view, and FIG. 4D is a cc cross-sectional view of FIG.
9A and 9B show a second intermediate material obtained by the fourth step, wherein FIG. 9A is a plan view, FIG. 9B is a cross-sectional view taken along line aa of FIG. 9A, and FIG. FIG. 4B is a cross-sectional view, and FIG. 4D is a cc cross-sectional view of FIG.
10A and 10B show a third intermediate material produced by the fifth step, wherein FIG. 10A is a plan view, FIG. 10B is a cross-sectional view taken along line aa of FIG. 10A, and FIG. FIG. 4B is a cross-sectional view, and FIG. 4D is a cc cross-sectional view of FIG.
11A and 11B show a rocker arm completed through the sixth step, wherein FIG. 11A is a plan view, FIG. 11B is a cross-sectional view taken along line aa of FIG. 11A, and FIG. (b) sectional drawing, (D) is cc sectional drawing of (A).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 1a Rocker arm 2, 2a Side wall part 3 First connection part 4, 4a Second connection part 5 Circular hole 6 First engagement part 7 Second engagement part 8 First base plate 9 Through hole 10 Reference numeral 10a Second base plate 11 First intermediate material 12 Curved portion 13 Second intermediate material 14 Third intermediate material 15 Arm portion 16 Reinforcement portion 17 Spherical concave portion 18 Spherical convex portion 19 Gap 20 Wing portion 21 Notch 22 Base portion 23 Intermediate material

Claims

A pair of side walls formed by performing plastic working on the metal plate and provided at an interval from each other, and a connecting portion for connecting one edge in the width direction of the both side walls are provided. , And an engagement portion that engages with the valve element or the swing support member, and the side wall portions are present at least on both side edges of a portion of the connection portion where the engagement portion exists. Instead, by abutting and fixing the distal end edges of the arms extending from one end in the longitudinal direction of these side walls to a part of the connecting portion, a reinforcing portion for securing rigidity of the connecting portion is provided. A rocker arm characterized in that a gap is interposed between both side edges of these connecting portions in the width direction and the reinforcing portion.

The engaging portion is a spherical concave portion formed on one surface of the connecting portion to oscillate the tip of the lash adjuster, which is a swing supporting member, so as to be freely displaceable. On the other hand, a bent portion is formed on the other surface side of the engaging portion, and the tip portions of a pair of arms extending from these side wall portions are opposite to the engaging portion on the other surface of the connecting portion. The rocker arm according to claim 1, wherein the rocker arm is welded and fixed to a part of the protruding spherical convex portion to form a reinforcing portion.